FLUE GAS DESULPHURISATION (FGD) SYSTEM - Chettinad Power Limited

2X660MW SUPER CRITICAL THERMAL POWER PLANT AT

THARANGAMBADINAGAPATTINAM DIST.TAMIL NADU

CONSULTANT

DEVELOPMENT CONSULTANTS PRIVATE LIMITED 191, ANNA SALAI, CHENNAI - 600006

BID SPECIFICATION NO. : 11Z02SPCG001

MMAAIINN PPLLAANNTT PPAACCKKAAGGEE

[[BBOOIILLEERR TTUURRBBIINNEE GGEENNEERRAATTOORR]]

VVOOLLUUMMEE :: IIII II

FFLLUUEE GGAASS DDEESSUULLPPHHUURRIISSAATTIIOONN ((FFGGDD)) SSYYSSTTEEMM

CPCPL-Super Critical TPP-Tharangambadi [2 x 660 MW] Main Plant Package CONTENTS DCPL-11Z02

MMAAIINN PPLLAANNTT PPAACCKKAAGGEE

[[BBOOIILLEERR TTUURRBBIINNEE GGEENNEERRAATTOORR]]

OVERALL CONTENTS

VOLUME-I : COMMERCIAL & GENERAL CONDITIONS OF CONTRACT

VOLUME-II : TECHNICAL SPECIFICATION VOLUME-III : BID PROPOSAL SHEETS [TECHNICAL PART]


CONTENTS VOLUME : II TECHNICAL SPECIFICATIONS VOLUME II-A : LEAD SPECIFICATION VOLUME II-B : SPECIFICATIONS FOR STEAM GENERATOR & AUXILIARIES VOLUME II-C : SPECIFICATIONS FOR TURBINE-GENERATOR, AUXILIARIES &

OTHER FEED CYCLE EQUIPMENT VOLUME II-D : SPECIFICATIONS FOR POWER CYCLE & OTHER PIPING,

VALVES & SPECIALTIES VOLUME II-E : SPECIFICATIONS FOR CONTROLS & INSTRUMENTATION VOLUME II-F/1 & : SPECIFICATIONS FOR ELECTRICAL EQUIPMENT & VOLUME II-F/2 ACCESSORIES [IN TWO VOLUMES] VOLUME II-G : SPECIFICATIONS FOR ELEVATORS VOLUME II-H : SPECIFICATIONS FOR MAIN, AUXILIARY & CLOSED CIRCUIT

COOLING WATER SYSTEMS & ACCESSORIES & MISCELLANEOUS SYSTEMS.

VOLUME II-I : FLUE GAS DESULPHURISATION (FGD) SYSTEM VOLUME II-J : TENDER DRAWINGS


VVOOLLUUMMEE :: IIII -- II

FFLLUUEE GGAASS DDEESSUULLPPHHUURRIISSAATTIIOONN ((FFGGDD)) SSYYSSTTEEMM


CONTENTS CLAUSE NO. DESCRIPTION

1.00.00 INDUCED DRAFT FANS

2.00.00 WET LIMESTONE EQUIPMENT

3.00.00 SULFUR DIOXIDE ABSORBER

4.00.00 GYPSUM DEWATERING EQUIPMENT

5.00.00 MECHANICAL AGITATORS

6.00.00 DUCTWORK

7.00.00 GAS-GAS HEAT EXCHANGER






13.00.00 DUCTWORK







20.00.00 DUCTWORK



CPCPL-Super Critical TPP-Tharangambadi [2 x 660 MW] Main Plant Package

VOL-II-I-SEC-I - 1

DCPL-11Z02

SECTION-I

FGD SYSTEM


1.01.00 SUMMARY:

1.01.01 Provide induced draft fans as required for proper operation of the plant.

1.01.02 All fans shall be complete with all accessories and auxiliaries specified.

1.02.00 REFERENCES:

1.02.01 Applicable Codes and Standards:

1.02.02 Design, construct, test, and erect equipment in accordance with applicable codes and standards including, but not limited to, the following:

1.02.02.01 American Society of Mechanical Engineers (ASME):

• Boiler and Pressure Vessel Code.

• B31.1 Code for Pressure Piping.

1.02.02.02 Anti-Friction Bearing Manufacturers Institute (AFBMA).

1.02.02.03 American Society for Testing and Materials (ASTM).

1.02.02.04 Heat Exchange Institute (HEI).

1.03.00 SUBMITTALS:

1.03.01 Submittals shall include the following:

1.03.01.01 General arrangement and outline information.

1.03.01.02 Foundation design information.

1.03.01.03 Erection information.

1.03.01.04 Piping connection information.

1.03.01.05 Instrumentation information.

1.03.01.06 Certified performance data, including at least the following:

• Performance curves showing flow vs. head, efficiency, and brake horsepower from zero flow to at least 120% of maximum design flow.

• For variable speed fans, submit performance curves as described above for maximum speed, minimum recommended speed, and at least 5 intermediate speeds.


VOL-II-I-SEC-I - 2

DCPL-11Z02

1.04.00 QUALITY ASSURANCE:

1.04.01 Experience:

1.04.01.01 All Equipment and appurtenances shall have an acceptable history of satisfactory reliable service in central station use for a period of at least three years at comparable temperature, pressure, voltage, and design stress levels.

1.04.01.02 Newly developed equipment with less than three years' actual service may be considered from established manufacturers, only if it has been adequately tested, meets requirements of this Contract, and is approved by the Owner.

1.04.01.03 Factory inspection shall be performed as follows:

1.04.01.04 Prior to shipment, manufacturer shall thoroughly inspect all parts of Equipment furnished by him to ensure sound material and first class workmanship. All rivets shall be tight, and welds shall be full thickness and without undercutting. Keys shall fit snugly, and rotors shall be secured firmly to shafts.

1.04.01.05 Welding on rotors for fans shall be examined by magnetic particle inspection. Magnetic particle inspection shall be performed on root pass and finished surfaces of all welds. On full penetration welds, the backside of root base shall be examined by magnetic particle inspection before depositing weld from backside. Welds shall be free from undercutting in excess of 0.4 millimeters in depth and free of cracks and fissures in excess of 6 millimeters in length.

1.04.01.06 The manufacturer shall furnish to Owner the Submittals and procedures for nondestructive testing which shall be performed on welds or base material of fans. Inspection of fans for compliance may be made by Owner.

1.04.01.07 Notify Owner at start of assembly and welding of fan rotors, so that they may have a representative present to inspect fan rotors during fabrication, if desired. This inspection will include:

• Manufacturer's nondestructive testing facilities.

• Examination of weld groove preparations on material being joined in assembly of fan wheels.

• Witness actual welding being performed on fan wheels.

• Witness nondestructive testing being performed on welds and base material of fan wheel.

• Verify that all other subassemblies are fabricated properly and in accordance with manufacturer's drawings and specifications.

1.04.02 Factory Tests:

1.04.02.01 Perform all manufacturers’ standard factory tests on equipment and material.

1.04.02.02 Perform all tests required by applicable codes and these Specifications.

1.04.02.03 Fan wheels with tip speeds exceeding 125 meters per second and which are not identical to fan wheels in successful commercial operation, shall be given an overspeed test as follows:


VOL-II-I-SEC-I - 3

DCPL-11Z02

• If operating temperature of fan is less than 94°C, the wheel shall be spun at 10% above maximum operating speed for a period of not less than three minutes.

• If operating temperature of fan is 94°C or more, the wheel shall be spun for a period of not less than three minutes at the speed calculated from the following formula:

Test speed = A*B/C

Where:

A = 110% of maximum operating speed

B = allowable stress at 38°C

C = allowable stress at operating temperature

• There shall be no permanent deformation of any part of wheel as a result of the overspeed test. After the test, all welds shall be examined for cracks by magnaflux or dye penetrant check.

1.04.02.04 Notify Owner when factory tests are to be made, so that they may have a representative present, if desired.

1.04.02.05 Factory test shall include mechanical balancing of all rotating parts.

1.04.02.06 Submit certificates of completion of factory tests as Submittals.

1.05.00 GENERAL PRODUCTS:

1.05.01 Lubrication systems shall operate in common between a fan and its driver and lubricated coupling system, if applicable, to ensure they operate to concurrently to protect the rotating equipment under all conditions.

1.05.02 Induced-Draft Fans:

1.05.02.01 Provide 2 x 50% capacity induced draft fans as required for the proper

operation of the plant.

1.05.02.02 The induced draft fans shall be designed and constructed to meet the following requirements: • The combined design capacity of all fans shall be 120% of the net flue

gas produced. The net flue gas produced is defined as the flue gas resulting from combustion at the maximum rating of the steam generator at the design excess air and using the “Design Coal” with the highest air demand, plus the air heater leakage specified above, plus all other leakages.

• Design static pressure shall be 140% of the static pressure required to withdraw the net flue gas produced.

• Design capacity and design static pressure shall be calculated assuming inlet gas temperature to be 25°C higher than the maximum operating inlet gas temperature.

1.05.02.03 Each induced draft fan shall be equipped with dampers as follows:

• Shutoff damper on outlet of fan.


VOL-II-I-SEC-I - 4

DCPL-11Z02

1.05.02.04 Each induced draft fan shall have inlet silencers; (if needed) to limit sound pressure level of operating fan and motor assembly in a free field.

1.05.02.05 Induced draft fan and motor bearings shall include vibration transducers.

1.06.00 CENTRIFUGAL FANS:

1.06.01 General:

1.06.01.01 Inlet guide vane control of the ID fans will not be allowed. Centrifugal ID fans shall utilize variable speed control.

1.06.01.02 Fans shall be designed and constructed to ensure reliability with a minimum number of scheduled outages for repairs and maintenance.

1.06.01.03 Fans shall be suitable for continuous operation at full or part load.

1.06.01.04 Fans and their ducts and flow regulating devices, dampers, vanes, or speed changing devices, shall be coordinated to give an installation which will be capable of providing parallel or single operation of any of the fans, without excessive vibration or fan noise as defined herein. This satisfactory performance shall be required throughout entire load range of fans, including operation at minimum flow settings with cold air.

1.06.01.05 Fans shall be double inlet, double width, shall be two-bearing design with rotor suspended between bearings with no overhung wheels.

1.06.01.06 Fan housing shall be as follows:

• Split so rotor is accessible and removable for normal maintenance without disconnecting housing from inlet or outlet ducts or foundation and without moving motor.

• Shaped for maximum streamline flow from inlet to outlet.

• Constructed from mild steel plate not less than 10 millimeters thick.

• Braced with structural steel welded to housing and designed for sufficient strength to prevent warping and excessive vibration under all operating conditions.

• Provided with airtight inspection doors where required.

• Provided with inlet and outlet connections of structural angle flanges for the following:

o Welding to similar flanges on ductwork with alignment bolts only provided, or

o Connections to similar flanges on ductwork by means of gaskets and bolts. Bolts shall be spaced not more than 65 millimeters apart.

• Provided with a 50 millimeter drain pipe connection welded to lowest point of fan scroll. Provide nipple and cap.

• Supported from concrete or structural steel base.

• Designed so a minimum distance of 300 millimeters will exist between bottom of housing and foundation to permit application of insulation and access to housing drain connection.


VOL-II-I-SEC-I - 5

DCPL-11Z02

1.06.02 Fan rotors shall be as follows:

1.06.02.01 Designed and constructed to keep stresses from rotation or temperature differential at a safe and conservative level.

• Fan rotors operating at temperatures below 260°C shall be designed so maximum calculated stress at any point on rotor, under any normal condition such as continuous operation or starting acceleration, will not exceed 50% of minimum ultimate tensile strength of rotor material at maximum operating temperature.

• Fan rotors operating at temperature above 260°C shall be designed so maximum calculated stress at any point on rotor, under any normal condition such as continuous operation or starting acceleration shall not exceed the smallest of the following values:

o 50% of yield strength of rotor material at maximum operating temperature.

o 80% of stress required to produce a secondary creep rate in rotor material of 1 percent in 100,000 hours at design temperature.

o 80% of stress required to produce rupture of rotor material in 100,000 hours at design temperature.

• Have center plates and shroud plates of mild or alloy steel. Tie rods between plates or blades will not be permitted.

• Balanced statically and dynamically so that vibration displacement at bearings measured on shaft at full load and full speed with a clean rotor will not exceed the following:

Maximum Vibration

Rotor Speed, rpm Displacement, Millimeters

Up to 600................................................. 0.05

600 to 900 ............................................... 0.03

Weight adjustment for balancing shall be by either addition or removal of metal.

• Constructed so that while rotor is turning, the run-out of similar points on rotor structure will not deviate from the median path by more than 0.375% of the wheel diameter.

• Designed and constructed so that the first critical speed of rotor is not less than 33% above normal operating speed for fans operating at temperatures up to 94°C and not less than 50% above normal operating speed for fans operating at temperatures of 94°C and above.

1.06.02.02 Fan shafts shall be as follows:

• Forged and heat-treated steel, accurately machined, with ground and polished journal and thrust bearing surfaces.

• Provided with seals to minimize leakage where the shaft penetrates the housing. Fans handling flue gas and having a positive pressure in the inlet box shall have a pressurized air-sealing arrangement where the shaft


VOL-II-I-SEC-I - 6

DCPL-11Z02

penetrates the housing. This sealing system shall be furnished with all blowers, motors, ducts, dampers, and any other equipment required to provide a complete system.

1.06.02.03 Bearings shall be suitable for continuous heavy-duty service and shall be as follows:

• Self-aligning, sleeve-type journal bearings designed with adequate lubrication for coast down without an external oil supply.

• Installed in a horizontal split housing or pedestal of structural steel or cast iron. Pedestals shall allow removal of bearings without removing rotor and shall be suitable for shimming.

• Located external to inlet boxes.

• Designed to withstand thrust unbalance resulting from shutoff of one inlet of a double inlet fan while the other inlet is open.

• Protected from weather on outdoor installations with a suitable rain hood and sun shield as recommended by manufacturer.

• Each bearing shall have bearing temperature thermocouple.

• Bearings shall have vibration transducers.

1.06.02.04 Lubrication of bearings shall be by an air- or water cooled forced circulating lube oil system as follows:

• Provide a separate skid-mounted lubrication system for each fan.

• Designed to meet the bearing lubrication and cooling requirements for fan and drive motor.

• Each lubrication system shall consist of mounting frame; one oil reservoir; reservoir ac immersion heaters; dual filters, changeable during operation with transfer valve; two 100% pumps with motors; two 100% oil coolers; two 100% cooling fans with motors if air-cooled, acoustic/thermal treatment; piping and instruments as required.

• Each pump, cooler, and cooler fan shall have adequate capacity to supply oil at the proper pressure and temperature to fan and drive motor.

• If bearings are not designed to have adequate lubrication for coast down after a failure of ac lube oil circulating pumps, provide a full-capacity emergency dc motor driven oil pump to supply oil during coast down, arranged for automatic starting and manual shutdown. Make provisions for manual start-up for testing.

• If bearings receive oil during start-up and coast down by means of splash, dip, or oil ring lubrication from a bearing oil reservoir, this reservoir shall not completely drain and shall retain sufficient oil for starting and stopping.

• Piping from reservoir to fans and back shall include flexible connections where required. Oil return lines from bearings to reservoir shall be designed with as much slope as possible, but in no case less than 40 mm per meter. All oil piping shall be traced with heating cable and insulated; heating cable shall be wired to terminal box on oil reservoir for connection the power supply. Provide thermostat for heating cable control.


VOL-II-I-SEC-I - 7

DCPL-11Z02

• Lubrication system shall be designed and fabricated in accordance with the following:

o Lubrication system shall be shop-fabricated, cleaned, flushed and protected with suitable rust-preventive coating.

o As far as practicable, this lubrication system shall be shop-assembled and shipped with equipment.

o Lubrication system piping 25 millimeters and smaller shall be stainless steel socket weld pipe or stainless-steel tubing with tubing fittings.

o Lubrication system piping over 25 millimeter in size shall be prefabricated welded stainless steel with flanged joints for field connections so no field welding is required.

o Provide connections and make provisions for field flushing.

o Provide connections for drainage and filling of the system with 125-mesh strainer on fill connection.

• System shall include all equipment necessary for heating and circulating oil prior to starting the fan and to maintain oil at the proper temperature during operation over the range of ambient temperatures specified in.

• Provide the following for each system.

o Pressure transmitters, temperature elements, and flow transmitters as required for alarms and interlocks.

o Pressure gauges and thermometers as required.

o Level sight glass on reservoir.

o Supervisory control of the skid will be through the distributed control system.

o Equipped with adequately sized integral lube oil reservoir.

1.06.02.05 Equipped with immersion heaters designed to continuously maintain lube oil in the bearing at starting temperature at the ambient temperature specified. Immersion heaters shall be complete with a thermostat located to accurately control lube oil temperature. Bearing pedestals, mounting plates, and soleplates shall be furnished as required to mount the equipment on the concrete foundation.

1.06.02.06 Each fan shall be equipped with a flexible coupling between the fan and motor.

1.06.02.07 Submit fan performance curves with proposal for range of operation from 0 to 120% of unit capacity.

1.06.02.08 Provide motor-operated turning gear for each fan specified or recommended to have one by fan manufacturer as follows:

• Turning gear shall be capable of turning a hot fan and motor.

• Turning gear shall be capable of starting the fan & motor from a dead stop

• Turning gear shall be mounted on fan or on stub shaft on back end of motor. Provide mounting plates as required.


VOL-II-I-SEC-I - 8

DCPL-11Z02

• Provide the following controls for each turning gear:

o Zero speed device to prevent engagement while rotor is turning.

o Electrically separate alarm contacts for turning gear disengaged.

• Provide motor drive complete with coupling and clutches required for automatic operation from the DCS.

1.07.00 AXIAL FANS:

1.07.01 General:

1.07.02 Fans shall be designed and constructed to ensure reliability with a minimum number of scheduled outages for repairs and maintenance.

1.07.03 Fans shall be suitable for continuous operation at full or part load.

1.07.04 Fans and their ducts, flow regulating devices, dampers, vanes, or speed changing devices, shall be coordinated to give an installation which will be capable of providing parallel or single operation of any of the fans, without excessive vibration, fan noise, or air or gas vibrations. This satisfactory performance shall be required throughout the entire load range of the fans, including operation at minimum flow settings with cold air.

1.07.05 Fans shall be axial flow with blade pitch variable during operation.

1.07.06 Fans shall be provided with vertical inlet and horizontal discharge.

1.07.07 Fans shall be mechanically balanced statically and dynamically for all operating conditions.

1.07.08 Fans shall be designed so that inlet box, rotor housing, diffuser, and recovery section form a one piece continuous structure when assembled.

1.07.09 Fan inlet, recovery, and diffuser sections shall be as follows:

1.07.09.01 Constructed of mild steel not less than 10 millimeter thick and of greater thickness if specified herein for a particular fan, and shall be continuously welded at all joints.

1.07.09.02 Braced with structural steel bracing welded to the structure and designed for sufficient strength to prevent warping and vibration under all operating conditions.

1.07.09.03 Provided with drilled flanges at inlet and outlet for bolted connections to similar flanges on ductwork and rotor housing by means of gaskets and bolts. Bolts shall be spaced not more than 65 millimeters apart.

1.07.09.04 Designed for airtight attachment to fan rotor housing.

1.07.09.05 Inlet box shall contain a welded hollow section through which motor shall connect to fan rotor.

1.07.09.06 Nose piece shall be properly contoured to provide even flow to fan wheel.

1.07.09.07 Provide a hinged access door of heavy construction on inlet and recovery sections. Doors shall be air and dust tight.

1.07.09.08 Provide a 150 millimeter drain pipe connection welded to lowest point on inlet section. Provide nipple and cap.


VOL-II-I-SEC-I - 9

DCPL-11Z02

1.07.09.09 Provide lifting lugs or eye bolts on all sections to facilitate erection and repair.

1.07.09.10 Provide stationary blades (stators) immediately after fan wheel to eliminate the spin the wheel imparts to air.

1.07.09.11 Diffuser and recovery section assembly shall provide a gradual transition from stationary blade section to discharge outlet with a maximum angle of 8° giving the greatest conversion of velocity head to static head with minimum loss.

1.07.10 Fan evase section, if required, shall be as specified follows:

1.07.10.01 Provided with lifting lugs or eye bolts as necessary to facilitate erection and repair.

1.07.10.02 Total included angle of section shall not exceed 16° and provide greatest conversion of velocity head to static head with minimum loss.

1.07.10.03 Expansion joints, if required shall be installed between diffuser outlet and evase section.

1.07.11 Fan rotor housing shall be as follows:

1.07.11.01 Split so rotor is accessible and removable for normal maintenance without removing drive motor:

1.07.11.02 Contractor shall make all special provisions required for removal of the rotor.

1.07.11.03 Shaped for maximum streamline flow from inlet to outlet.

1.07.11.04 Constructed from mild steel plate not less than 20 millimeter thick.

1.07.11.05 Braced with structural steel welded to housing and designed for sufficient strength to prevent warping and vibration under all operating conditions.

1.07.11.06 Housing section about fan wheel shall be accurately machined to assure required tolerance is maintained between blade tip and housing section.

1.07.11.07 Provided with airtight inspection doors for blade access, inspection, repair, and removal.

1.07.11.08 Provided with a 50 millimeter pipe connection welded to lowest point on fan housing. Provide nipple and cap.

1.07.11.09 Designed so a minimum distance of 300 millimeters will exist between bottom of housing and foundation to permit application of insulation and access to housing drain connection.

1.07.11.10 Provide sufficient lifting lugs or eye bolts on all sections as necessary to facilitate erection and repair.

1.07.12 Fan rotors shall be as follows:

1.07.12.01 Designed and constructed to keep stresses from rotation or temperature differential at a safe and conservative level.

• Fan rotors operating at temperatures below 260°C shall be designed so maximum calculated stress at any point on rotor, under any normal condition such as continuous operation or starting acceleration, will not exceed 50% of minimum ultimate tensile strength of rotor material at maximum operating temperature.


VOL-II-I-SEC-I - 10

DCPL-11Z02

• Fan rotors operating at temperature above 260°C shall be designed so maximum calculated stress at any point on rotor, under any normal condition such as continuous operation or starting acceleration, shall not exceed smallest of the following values:

o 80% of stress required to produce a secondary creep rate in rotor material of 1 percent in 100,000 hours at design temperature.

o 80% of stress required to produce rupture of rotor material in 100,000 hours at design temperature.

1.07.12.02 Balanced statically and dynamically. Weight adjustment for balancing shall be either by means of fused addition or removal of metal.

1.07.12.03 Constructed so that while rotor is turning, the run-out of similar points on rotor structure will not deviate from median path by more than 3 millimeters.

1.07.12.04 Designed and constructed so first critical speed of rotor is not less than 33% above normal operating speed for fans operating at temperatures up to 94°C and not less than 50% above normal operating speed for fans operating at temperatures of 94°C and above.

1.07.13 Fan shafts shall be as follows:

1.07.13.01 Forged and heat-treated steel, accurately machined, with ground and polished journal and thrust bearing surfaces.

1.07.13.02 Provided with seals to minimize leakage where shaft penetrates inlet box. Fans handling flue gas and having a positive pressure in inlet box shall have a pressurized air-sealing arrangement where shaft penetrates housing. This sealing system shall be furnished with all blowers, motors, ducts, dampers, and any other equipment required to provide a complete system.

1.07.13.03 Be statically and dynamically balanced.

1.07.13.04 First critical speed shall be at least 1.25 times the design operating speed.

1.07.13.05 Provide machined and drilled mounting for axial motion probe to determine shaft position.

1.07.14 Bearings shall be suitable for continuous heavy-duty service and shall be as follows:

1.07.14.01 Self-aligning, sleeve-type, journal bearings or anti-friction bearings designed with adequate lubrication for coast down without an external oil supply.

1.07.14.02 Bearings external to fan shall be protected from weather on outdoor installations with a suitable rain hood and sun shield as recommended by manufacturer.

1.07.14.03 Each bearing or group of bearings except blade shaft bearings shall have bearing temperature thermocouples as.

1.07.14.04 Bearings on specified fans shall include vibration transducers. Provide suitable means for routing vibration probe wiring to fan exterior in a safe, protected, and long life manner, subject to approval by Owner.

1.07.14.05 Thrust bearings and their housing shall be capable of taking thrust of all fan operating conditions from shutoff to test block.


VOL-II-I-SEC-I - 11

DCPL-11Z02

1.07.14.06 Anti-friction bearings shall be rated AFBMA 100,000-hour minimum life at maximum vibration, unbalance, and thrust conditions.

1.07.14.07 Blade shaft bearings shall be ball thrust bearings and shall be as follows:

• Designed for oscillating movement and a thrust rating of at least 1.5 times maximum thrust.

• Permanently lubricated with a high load lubricant and provided with seals to prevent infiltration of dirt and dust.

• Contractor shall describe in his Proposal the procedure for inspection, relubrication, and replacement of blade shaft bearings.

1.07.15 Fan blades and blade shafts shall be made of either forged or cast aluminum, forged or cast steel, cast iron or nodular iron, and shall be as follows:

1.07.15.01 Fan blades operating at temperatures above 94°C shall be wear-resistant forged or cast steel.

1.07.15.02 Cast or forged aluminum fan blades shall not be used for operating at temperatures above 94°C.

1.07.15.03 Blade shafts shall be designed to support blade under all operating conditions of speed, load, and temperature.

1.07.16 Fan variable pitch blade control system shall be as follows:

1.07.16.01 Each variable pitch blade control system shall be capable of adjusting the blade pitch angle from maximum to zero in 30 seconds or less.

1.07.16.02 System shall consist of a hydraulically-operated mechanism mounted completely within fan inner housing assembly.

1.07.16.03 Oil used in servo motor may be from lube oil system serving fan bearings or may be from a separate system. If a separate system, then it shall meet all Specifications for lubrication system.

1.07.16.04 All interconnecting hydraulic piping and hoses for mechanism inlet and discharge oil shall be provided. Piping shall be all stainless steel.

1.07.16.05 Blade pitch control arms shall be attached to blade shafts in a positive and secure manner without welding and shall be designed so that allowable stress is at least 1.5 times the maximum operating stress. Contractor shall supply details of attachment with Proposal.

1.07.16.06 Designed so that upon loss of control or power, the blades will remain in their last set position.

1.07.17 Lubrication of bearings shall be by an air or water cooled forced circulating lube oil system as follows:

1.07.17.01 Provide a separate skid-mounted lubrication system for each fan.

1.07.17.02 Designed to meet the bearing lubrication and cooling requirements for fan and drive motor.

1.07.17.03 Each lubrication system shall consist of mounting frame; one oil reservoir; reservoir ac immersion heaters; dual filters, changeable during operation with transfer valve; two 100% pumps with motors; two 100% oil coolers; two 100%


VOL-II-I-SEC-I - 12

DCPL-11Z02

cooling fans with motors, if air-cooled, acoustic/thermal treatment; piping and instruments as required.

1.07.17.04 Each pump, cooler, and cooler fan shall have adequate capacity to supply oil at the proper pressure and temperature to fan and drive motor.

1.07.17.05 If bearings are not designed to have adequate lubrication for coast down after a failure of ac lube oil circulating pumps, provide a full-capacity emergency dc motor driven oil pump to supply oil during coast down, arranged for automatic starting and manual shutdown. Make provisions for manual start-up for testing.

1.07.17.06 If bearings receive oil during start-up and coast down by means of splash, dip, or oil ring lubrication from a bearing oil reservoir, this reservoir shall not completely drain and shall retain sufficient oil for starting and stopping.

1.07.17.07 Piping from reservoir to fans and back shall include flexible connections where required. Oil return lines from bearings to reservoir shall be designed with as much slope as possible, but in no case less than 40 mm per meter. All oil piping shall be traced with heating cable and insulated; heating cable shall be wired to terminal box on oil reservoir for connection to the power supply. Provide thermostat for heating cable control.

1.07.17.08 Lubrication system shall be designed and fabricated in accordance with the following:

• Lubrication system shall be shop-fabricated, cleaned, flushed and protected with suitable rust-preventive coating.

• As far as practicable, this lubrication system shall be shop-assembled and shipped with equipment.

• Lubrication system piping 25 millimeters and smaller shall be stainless steel socket weld pipe or stainless-steel tubing with tubing fittings.

• Lubrication system piping over 25 millimeter in size shall be prefabricated welded stainless steel with flanged joints for field connections so no field welding is required.

• Provide connections and make provisions for field flushing.

• Provide connections for drainage and filling of the system with 125-mesh strainer on fill connection.

1.07.17.09 System shall include all equipment necessary for heating and circulating oil prior to starting the fan and to maintain oil at the proper temperature during operation over the range of ambient temperatures specified.

1.07.17.10 Provide the following for each system.

• Pressure transmitters, temperature elements, and flow transmitters as required for alarms and interlocks.

• Pressure gauges and thermometers as required.

• Level sight glass on reservoir.

• Supervisory control of the skid will be through the distributed control system.


VOL-II-I-SEC-I - 13

DCPL-11Z02

1.07.17.11 Equipped with adequately sized integral lube oil reservoir.

1.07.17.12 Equipped with immersion heaters designed to continuously maintain lube oil in the bearing at starting temperature at the ambient temperature specified. Immersion heaters shall be complete with a thermostat located to accurately control lube oil temperature.

1.07.18 Bearing pedestals, mounting plates, and soleplates shall be furnished as required. Contractor design an economical and stable foundation, including all imbalance dynamic loads, lateral loads, mass and stiffness requirements, and foundation bolts torque requirements.

1.07.19 Each fan shall be furnished with a single-speed motor drive.

1.07.20 Each fan shall be equipped with a flexible coupling between the fan and motor drive.

1.07.21 Each fan shall be provided with all instruments and controls.

1.07.22 Provide motor-operated turning gear if required, for each fan specified as follows:

1.07.22.01 Turning gear shall be capable of turning a hot fan and motor.

1.07.22.02 Turning gear shall be capable of starting fan and motor from a dead stop.

1.07.22.03 Turning gear shall be mounted on fan or on stub shaft on back end of motor. Provide mounting plates as required.

1.07.22.04 Provide the following controls for each turning gear:

• Zero speed device to prevent engagement while rotor is turning.

• Electrically separate alarm contacts for turning gear disengaged.

1.07.22.05 Provide motor drive complete with coupling and clutches required for automatic operation from the DCS.

1.07.23 Provide sealing/cooling system for each fan specified or recommended to have one by fan manufacturer as follows:

1.07.23.01 System shall provide a source of clean, filtered, pressurized air to seal and cool rotor, hub, and blade pitch change mechanism.

1.07.23.02 System shall be complete with filters, blowers, silencers, acoustic treatment, motors and instruments, and controls as required for a complete system.

1.07.23.03 System shall be suitable for remote location, above grade, if not an integral part of fan.

1.07.24 Stall curve of each fan shall be verified by Contractor as follows:

1.07.24.01 By operation of installed fans under actual or simulated operating conditions at the following blade angle settings:

• Test block.

• 120% of test block or maximum that fan, motor, and/or system can operate continuously without damage, whichever is smaller.

• 100%, 80%, 60%, 30%, and 20% of plant rated load.


VOL-II-I-SEC-I - 14

DCPL-11Z02

1.07.24.02 Provide a test engineer to direct test.

1.07.24.03 Provide all instrumentation required, if station instrumentation is not acceptable.

1.07.24.04 Tests shall be completed and report issued no later than 120 days after commercial operation.

1.07.25 Submit fan performance curves with Proposal for range of operation from 0 to 120% of unit capacity.

1.07.26 Provide a stall protection package to give positive indication/prevention of fan stall.


2.01.00 SUMMARY:

2.01.01 Furnish and deliver the following as required and specified for the Flue Gas Desulfurization (FGD) System:

2.01.01.01 Two ball mills

2.01.01.02 Mill motors,

2.01.01.03 Gear reducers,

2.01.01.04 Ball charge,

2.01.01.05 Air clutch,

2.01.01.06 Classifiers,

2.01.01.07 Mill product tanks,

2.01.01.08 Mill product pumps,

2.01.01.09 Agitators,

2.01.01.10 Feed chute,

2.01.01.11 Discharge chute,

2.01.01.12 Instruments and controls.

2.02.00 REFERENCES:

2.02.01 Design, fabricate and test equipment and materials in accordance with manufacturers' procedures and the following applicable codes and standards:

2.02.01.01 American Gear Manufacturers Association (AGMA).

2.02.01.02 American Institute of Steel Construction (AISC): Manual of Steel Construction.

a. Manual of Steel Construction.

b. Quality Criteria and Inspection Standards.

2.02.01.03 American Iron and Steel Institute (AISI).


VOL-II-I-SEC-I - 15

DCPL-11Z02

2.02.01.04 American National Standards Institute (ANSI):

a. B16.5 - Steel Pipe Flanges and Flanged Fittings.

b. B31.1 - Power Piping.

c. C1 – National Electrical Code (NEC).

d. C42.1 – Definition of Electrical Terms, Group 10 Rotating Machinery.

2.02.01.05 American Society of Testing and Materials (ASTM):

a. A36 – Structural Steel.

b. A48 – Gray Iron Castings.

c. A240 - Standard Specification for Heat-Resisting Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels.

2.02.01.06 American Welding society (AWS):

a. D1.1 – Code for Arc and Gas Welding.

2.02.01.07 Anti-Friction Bearing Manufacturer's Institute (AFBMA).

2.02.01.08 Heat Exchange Institute (HEI).

2.02.01.09 National Electrical Manufacturer’s Association (NEMA).

2.02.01.10 Tubular Heat Exchanger Manufacturer's Association (TEMA).


2.03.01 All Equipment and appurtenances of the Limestone Grinding system (including all subassemblies there of) shall have an acceptable history of satisfactory reliable service in central station use for a period of at least three years at comparable temperature, pressure, and design stress levels.

2.03.02 Factory inspection shall be performed as follows:

2.03.02.01 Prior to shipment, manufacturer shall thoroughly inspect all parts of equipment furnished to ensure sound material and first class workmanship. All fasteners shall be tight, and welds shall be full thickness and without undercutting. Keys shall fit snugly, and rotors shall be secured firmly to shafts.


2.03.03.01 Perform all manufacturer's standard factory tests on equipment and material.


2.03.03.03 Notify Owner when factory tests are to be performed, so that they may have a representative present, if desired.

2.03.03.04 Factory tests shall include mechanical balancing of all rotating parts.


2.04.00 WET BALL MILLS:

2.04.01 General:


VOL-II-I-SEC-I - 16

DCPL-11Z02

2.04.01.01 Each ball mill shall be sized to process the maximum daily limestone required by Unit 1 and Unit 2 in a 12 hour grinding period.

2.04.01.02 Design system to operate continuously at rated output on a 24-hour basis or in daily start-stop operation.

2.04.01.03 All gears and bearings shall have a 30-year minimum design life.

2.04.01.04 Ball charge shall be suitably designed, sized, and selected hardened steel balls to accomplish the desired limestone size reduction and minimize ball consumption.

2.04.01.05 Adjust all rotating parts which may be subjected to excessive vibration due to lack of balance for static and dynamic balance at the normal operating speed. All rotating parts shall be designed to safely withstand all acceleration forces which may occur.

2.04.01.06 All parts subject to heavy wear shall be designed so that they may be replaced.

2.04.01.07 Provide flow measurement for mill supply.

2.04.01.08 Provide density measurement for the following points.

a. Hydrocyclone Feed

b. Limestone return to the reagent feed tank

2.04.01.09 Provide manual valves and sample connections for the following point.

a. Hydrocyclone Overflow

b. Hydrocyclone Underflow

2.04.01.10 The mill product tank shall be designed with an agitator to keep solids from settling.

2.04.02 Mill shall be as follows:

2.04.02.01 Have horizontal shaft configuration.

2.04.02.02 All portions subject to the process liquid shall be rubber-lined a minimum of 1/4-inch thickness to protect from corrosion and abrasion.

2.04.02.03 Be provided with inlet feed chutes with flanged connection.

a. Shall have labyrinth and seals as required to prevent leakage.

b. Shall include ball charging system consisting of a ball hoist, access and ball loading chute. Configure ball charging system to be able to operate with one operator.

2.04.02.04 Mill Shell:

a. Shall be of steel plate conforming to ASTM A36 or ASTM equivalent material as approved by Owner.

b. Provide with two reinforced manholes located 180 degrees apart. Construct openings large enough to pass all wearing parts or 18” x 28” whichever is larger. Construct manhole doors watertight and provide with ASTM A197 Gr. B7 bolts.

2.04.02.05 Mill Liner: Molded rubber with steel reinforcement.


VOL-II-I-SEC-I - 17

DCPL-11Z02

2.04.02.06 Mill Heads:

a. Shall be cast steel, Mechanite or cast “GM” type.

b. Heads shall be machined for a male-female fit with shell flanges. Flanges shall be bolted.

2.04.02.07 Mill Discharge Arrangement:

a. Mill discharge shall be overflow type.

b. Discharge shall be provided with a reverse helix to return balls, rocks, etc., to the mill.

c. Provide 317L stainless steel discharge screen and housing with quick-opening access door a minimum of 24” x 24”.

d. Provide rubber lined discharge chutes and tramp material chutes for each mill.

2.04.03 Trunnions and Bearings:

2.04.03.01 Trunnions shall be cast integral with mill heads for mills that are trunnion supported.

2.04.03.02 Trunnion bearing assemblies shall be self-aligning type, with 120-degree arc surface bearing minimum and provided with adequate seals to prevent oil leakage.

2.04.03.03 Shell supported mill bearing assemblies shall be supported at the periphery by self-aligning slide shoes.

2.04.03.04 Bearing surface of bearing inserts shall be Babbitt metal or SAG-67 bronze.

2.04.03.05 Provide with bearing thermocouples.

2.04.03.06 Bearing Lubrication:

a. Provide a skid-mounted lubrication system for each ball mill. The system shall provide low-pressure oil to lubricate the bearings during operation and a high-pressure oil supply to “float” the mills during start-up.

b. Each lubrication system shall consist of a lube oil pump, a hydrostatic pump, oil reservoir with heater, filter, pressure relief valves, air cooled oil coolers, piping, valves and instrumentation. The system shall be factory assembled, piped and wired. Arrange so that any piece of equipment can be easily removed.

c. Oil for the hydrostatic pumps shall be provided from the lube oil pumps downstream of the oil filter. Normally the hydrostatic pumps will be operated only for the mill start-up; however, design the system for continuous operation of both hydrostatic and lube oil pumps.

d. The oil reservoirs shall have a minimum capacity from low to normal operating levels of three months’ oil consumption. Equip oil reservoir with a level indicator, low level switch, and temperature-controlled electric heaters. Heaters shall be 400-volt, 3-phase, 50-hertz. Provide drain and fill piping connections to a location where lube oil system can be conveniently drained, flushed and refilled.


VOL-II-I-SEC-I - 18

DCPL-11Z02

e. Provide a full-capacity stainless-steel oil filter for each system. The filters shall have a minimum open area of six times the pipe area. Provide a local filter differential pressure indication and include provisions for easy cleaning of the filter.

f. Provide a full-capacity air cooled oil cooler for system. The oil cooler tube material shall be stainless steel. Cooler shall be readily dismantled for cleaning.

g. Oil piping shall be as follows:

(1) Use stainless tubing and stainless-steel Swagelok fittings for all piping systems one inch and smaller.

(2) Piping larger than one inch shall be stainless steel, welded or flanged prefabricated and assembled so that no field welding is required for assembly.

(3) Adequately support oil piping to prevent mechanical failure due to thermal stresses, vibration and all other causes.

(4) Include flexible connections where required. Design oil return lines with as much slope as possible.

(5) Provide field piping between lube oil system and bearings. Piping at bearings and lube oil system shall be brought to a single return connection.

2.04.03.07 Provide instrumentation for the lubrication system including the following and as required for proper operation:

a. Pressure Switches:

(1) Lube oil pump discharge pressure low.

(2) Hydrostatic pump discharge pressure low.

(3) Low lube oil pressure at each bearing.

(4) Low hydrostatic oil pressure at each bearing for permissive to start mill.

(5) Oil filter high differential pressure.

b. Flow Switches:

(1) Low lube oil flow at each bearing.

(2) Low hydrostatic oil flow at each bearing.

c. Temperature Switches:

(1) Lube oil temperature high.

(2) Lube oil temperature low.

d. Thermocouples: Provide a pipe thermocouple at the discharge of the oil cooler for remote indication of oil temperature.

e. Lube oil temperature control systems to automatically maintain lube oil temperature at the set point.

f. Provide containment for oil and grease as required.


VOL-II-I-SEC-I - 19

DCPL-11Z02

2.04.04 Girth Gear and Pinions:

2.04.04.01 Pinions shall be of forged steel, with shaft forged integral with pinion.

2.04.04.02 Pinion shaft bearings shall be self-aligning, antifriction (spherical roller) bearings. Both shall be symmetrically constructed so they may be reversed in their mountings to expose a new wearing surface.

2.04.04.03 Pinions and girth gear shall be reversible and conform to AGMA 321.05.

2.04.04.04 Provide dust-tight enclosure.

2.04.04.05 Locate pinion and girth gear on discharge ends of mills.

2.04.04.06 Provide thermocouples in each bearing.

2.04.04.07 Gears with teeth cut into shaft will not be allowed.

2.04.04.08 Provide an automatic gear spray lubrication system. This system shall include an air-operated barrel pumping unit, air filter pressure regulator, panel, timers, hydraulic control valves, pressure indicators, metering valves, spray nozzles and other equipment and controls required to make a complete system. Provide all interconnecting piping and hoses.

2.04.05 Provide air operated clutch assembly for disengaging the mill from the motor. Clutch shall be designed to provide a minimum of 140 percent of the motor horsepower rating at an air supply pressure of 60 psig.

2.04.06 Provide electric motors and couplings.

2.04.07 Speed Reducers for Gear and Pinion Drives:

2.04.07.01 Parallel shaft, enclosed-type helical gear reducers with roller bearings and dual-lip seals in accordance with AGMA standards 151.02, 271.03 and 420.03.

2.04.07.02 Size for a service factor of 1.75 based on mill design horsepower, but not less than that required for the motor starting torque.

2.04.07.03 Bearings shall be AFBMA 60,000-hour minimum L10 life.

2.04.07.04 Chain drives will not be permitted.

2.04.07.05 Cover unused shaft extensions.

2.04.07.06 Reducer/motor support frame shall be as follows:

a. Fabricated of structural steel and heavy plate extending the full length of reducer and driver.

b. Designed to adequately support equipment under all operating conditions without grout fill inside of the frame.

c. Not be covered with a thin steel plate which requires grouting under the plate. Grout shall be required under the basic frame only.

d. The reducer dowelled to the frame in the shop; the driver will be dowelled in the field.

e. Furnished with all bolts or screws for attaching reducer and motor drive to the support frame.

2.04.08 Sole Plates:


VOL-II-I-SEC-I - 20

DCPL-11Z02

2.04.08.01 Provide sole plates which are separate from the equipment, to permit all bearing housings, gear reducers, motors and accessories to be removed and replaced without regrouting and to permit realignment by shimming and redoweling.

2.04.08.02 Separately anchor to the concrete foundation and provide with jacking screws for ease of alignment.

2.04.08.03 Be fully machined on the top surface and have a thickness of not less than 1/24 of the greatest dimension of the sole plate.

2.04.08.04 Be cast iron or steel, with static loads not exceeding 14,000 kPa on the grout and dynamic plus static loads not exceeding 20,000 kPa.

2.05.00 CLASSIFIERS:

2.05.01 Provide a radial manifold classifier assembly for each mill, complete with cyclone classifiers, overflow and underflow launders, valves, pressure gauges, vents and all internal piping.

2.05.02 Provide heavy-duty, rubber lining in all parts of the system exposed to slurry.

2.05.03 Provide cyclone linings of rubber to be easily replaced with either rubber or ceramic.

2.05.04 Design of classifier assembly shall be such that each assembly will have a feed connection and overflow and underflow connections for a total of three connections.

2.05.05 All connections shall be flanged.

2.05.06 Provide removable covers for the underflow launder.

2.05.07 Provide test ports to sample feed, underflow and overflow from each hydrocyclone set.

2.05.08 Classifiers shall have no moving parts.

2.05.09 Each classifier assembly shall have two spare cyclones (minimum). All cyclones shall have inlet knife-gate isolation valves.

2.06.00 MILL PRODUCT TANKS:

2.06.01 Provide one rubber-lined mill product tank per ball mill

2.06.02 Provide each tank with an agitator.

2.06.03 Provide internal baffles as recommended by the mixer manufacturer.

2.06.04 Provide flanged connections for mill discharge, tank overflow, drain, cleanout, pump suction and reclaim water inlet.

2.07.00 FEED AND DISCHARGE CHUTES:

2.07.01 Provide the following connecting chutes for each mill:

2.07.01.01 Mill feed chute to connect the weigh feeder to the ball mill. This chute shall include flanged connections for the classifier underflow and the addition of reclaim water.

2.07.01.02 Mill discharge chute to the mill product tank and tramp material chute.

2.07.01.03 Ball loading chutes to add grinding balls to the mills.


VOL-II-I-SEC-I - 21

DCPL-11Z02

2.07.02 The connecting chutes shall be standard weight piping or 6 mm steel. Chute materials shall be selected to provide long service life considering erosion and corrosion conditions. Chute material shall be subject to Owner’s approval.

2.07.03 Provide flexible connections as required.


3.01.00 SUMMARY:

3.01.01 Furnish and erect the following as required and specified for the unit.

3.01.01.01 Absorbers and reaction tanks complete with inlet and outlet flanges.

3.01.01.02 Mechanical agitators.

3.01.01.03 Recycle pumps, piping, spray headers and nozzles.

3.01.01.04 Mist eliminators and mist eliminator wash systems.

3.01.01.05 Oxidation air blowers, air saturation systems, piping and injection pipes.

3.01.01.06 Absorber inlet quench systems.

3.01.01.07 Absorber and reaction tank support steel.

3.01.01.08 Arrangement and access for maintenance, monitoring and operation.

3.01.01.09 Instrumentation.

3.01.01.10 Field services for erection and startup.

3.01.02 Design of the absorber shall be based on meeting the performance conditions specified with a completely mechanical system design and shall not include the use of any organic additives to achieve the performance guarantees.

3.02.00 REFERENCES:

3.02.01 Design, fabricate and test equipment and materials in accordance with manufacturers' procedures and the following applicable codes and standards:

3.02.01.01 American Institute of Steel Construction (AISC): Manual of Steel Construction.

a. Manual of Steel Construction.

b. Quality Criteria and Inspection Standards.

3.02.01.02 American National Standards Institute (ANSI):

a. B16.5 - Steel Pipe Flanges and Flanged Fittings.

b. B31.1 - Power Piping.

c. C2 - National Electrical Safety Code.

3.02.01.03 American Petroleum Institute (API):

a. 650 - Welded Steel Tanks for Oil Storage.



VOL-II-I-SEC-I - 22

DCPL-11Z02

a. Boiler and Pressure Vessel Code:

(1) Section V - Nondestructive Examinations.

(2) Section IX - Welding and Brazing Qualifications.

3.02.01.05 American Society of Nondestructive Testing (ASNT).

3.02.01.06 American Society of Testing and Materials (ASTM):

a. A240 - Standard Specification for Heat-Resisting Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels.

b. A380 - Standard Recommended Practice for Cleaning and Descaling Stainless Steel Parts, Equipment and Systems.

c. B581 - Standard Specification for Nickel-Chromium-Iron-Molybdenum-Copper Alloy Rod.

d. B582 - Standard Specification for Nickel-Chromium-Iron-Molybdenum-Copper Alloy Plate, Sheet and Strip.

e. B691 - Iron-Nickel-Chromium-Molybdenum Alloys (UNS N08366 and UNS N08367) Rod, Bar, and Wire.

f. D4385 – Standard Practice for Classifying Visual Defects in Thremosetting Reinforced Plastic Pultruded Products.

g. E84 – Standard Test Method for Surface Burning

h. E674 - Standard Specification for Industrial Perforated Plate and Screens (Round Opening Series).

i. G4 - Conducting Plant Corrosion Tests.

3.03.00 SUBMITTALS:

3.03.01 Arrangement drawings, outline drawings, materials of construction, and bills of material.

3.03.02 Complete material and water balances, including water required for absorber quench system.

3.03.03 Drawings of all module internals including mist eliminators, mist eliminator wash system, recycle spray system, perforated trays (if provided), oxidation sparger and absorber quench header.


3.04.01 All Equipment and appurtenances of the FGD System (including all subassemblies there of) shall have an acceptable history of satisfactory reliable service in central station use for a period of at least three years at comparable temperature, pressure, and design stress levels.




VOL-II-I-SEC-I - 23

DCPL-11Z02







3.04.04 Field Testing:

3.04.04.01 The absorbers and reaction vessels shall be field tested for tightness including smoke tests as specified for ductwork.

3.05.00 MANDATORY SPARE PARTS:

3.05.01 Provide spare parts as follows:

3.05.02 Ten (10) percent extra recycle spray nozzles.

3.05.03 Ten (10) percent extra mist eliminator wash nozzles.

3.05.04 Ten (10) percent extra nuts and bolts for absorber module, for the recycle spray headers, perforated trays (if provided), and mist eliminator wash headers.

3.06.00 GENERAL DESIGN:

3.06.01 Provide stairs, walkways, platforms, etc., required to provide access to areas requiring periodic maintenance or inspection.

3.06.01.01 Design Loads:

a. Dead-Loads:

(1) Operating dead-load shall be the weight of the vessel complete with all appurtenances including contents and internal linings.

(2) Test dead-load shall be the operating dead-load of the vessel.

b. External Loads:

(1) Design vessels, along with all components, for seismic loads as specified.

(2) Design vessels, along with all components, for wind loading as specified.

c. Equipment loads shall consist of loads resulting from piping, pumps, ductwork, platforms, ladders and other appurtenances reaction forces on the vessels.

(1) Design Conditions: All vessels, their supports and appurtenances shall be designed to resist the following forces and loads or any combination thereof.

(a) Tests:

1) Test dead-load.


VOL-II-I-SEC-I - 24

DCPL-11Z02

2) Test contents.

3) Test pressure.

(b) Operation:

1) Operating dead-load.

2) Live load.

3) Design pressures as specified the ductwork

4) Variable operating conditions such as vibration, temperature, etc.

(c) Wind or earthquake force, whichever is the larger.

3.06.02 No internal supports or other internal protrusions (except baffles, turning vanes, spray headers, perforated trays, mist eliminators (including supports and wash piping), agitators, oxidation piping, and safety lugs) shall be permitted in the absorber design.

3.06.03 Vessels shall be shop fabricated in the largest sections practical and limited only by shipment and erection constraints so as to minimize field welding. Field splices shall be shown on submittal drawings.

3.06.04 The FGD Systems shall be designed to maintain acid gas emission rates as specified at all times that fuel is being burned in the steam generator (boiler), including start-up and shutdown. The FGD System shall be designed to attain the removal efficiency for SO2 specified herein under all operating conditions.

3.06.05 The Contractor shall design the Flue Gas Desulfurization Systems to limit chloride concentrations to 20,000 ppm with excursions not to exceed 25,000 ppm.

3.06.06 The Contractor shall include an Oxidation Air System as part of the Flue Gas Desulfurization system. The Oxidation Air System shall oxidize a minimum of 99% of the calcium sulfite hemihydrate (CaSO3• ½H2O) formed upon the reaction of calcium carbonate (CaCO3) with the absorbed sulfur dioxide (SO2), to calcium sulfate dihydrate (CaSO4•2H2O).

3.06.07 The Contractor shall design the FGD system for disposal of absorber waste slurry through the dewatering system. Reclaimed water shall be returned from the dewatering system for reuse in the FGD system.

3.06.08 The Contractor shall guarantee the maximum flue gas pressure drop across the FGD systems while operating in ranges specified and burning any fuel or combination of fuels within ranges specified, including the following scenarios:

3.06.08.01 All absorber recycle pumps in service.

3.06.08.02 One absorber recycle pump out of service.

3.07.00 ABSORBER:

3.07.01 Provide one (1) absorber for each unit (one per boiler)

3.07.02 The absorber shall be designed to meet the SOx removal guarantee with one of the spray levels out of service and the gas-gas heat exchanger leakage at


VOL-II-I-SEC-I - 25

DCPL-11Z02

its maximum. See the gas-gas heat exchanger leakage requirements specified in Clause 7 of this Section VII.

3.07.03 The minimum liquid to gas ratios (based on saturated gas volume, maximum total gas flow) to obtain guaranteed SO2 removal shall be based on Contractor’s experience but not be less than 10 liters/actual cubic meter for an open spray tower and 8.6 liters/actual cubic meter for absorbers that include a contact tray. Contractor shall provide written justification for the L/G ratio taking into account process variables such as gas volume flow, SO2 concentration, chloride concentration, and SO2 removal performance.

3.07.04 The absorption system shall have a maximum system stoichiometry as guaranteed.

3.07.05 The Contractor shall design the absorber module for a maximum superficial gas velocity of 4.3 m/sec based on the saturated gas condition corresponding to the maximum gas flow.

3.07.06 Provide 100 mm diameter instrument test ports in the absorber vessel with blind flanges to measure duct pressure at the inlet and outlet of each mist eliminator level.

3.07.07 Provide at least four (4) 100 mm diameter instrument test port with blind flange at the absorber inlet nozzle.

3.07.08 The absorber shall be of counter current vertical spray tower design. Designs using perforated trays to enhance gas/liquid contact are acceptable. Perforated trays shall be as specified. Packed towers are not acceptable.

3.07.09 Absorber vessel shall be all welded construction and shall be designed in accordance with API 650 Welded Steel Tanks for Oil Storage.

3.07.10 Design to ASME allowable stresses for operating conditions specified with allowable one third overstress for wind or seismic loading. Yield strength shall be reduced as required for elevated temperature conditions.

3.07.11 Absorber, reaction vessel, mist eliminators, spray nozzles, and piping shall be designed to minimize erosion, corrosion, cementation, and plugging.

3.07.12 Furnish complete with inlet nozzle, inlet ductwork, outlet ductwork, support steel, mist eliminators, external recycle piping, oxidation air sparger, all internal spray nozzles, internal piping, and connections as specified.

3.07.13 The inlet nozzle is the section of absorber module and inlet duct exposed to the wet/dry interface. Design the inlet nozzle so that the wet/dry interface is within the inlet nozzle. As a minimum, the inlet nozzle shall include a 1 meter wide section inside the absorber module surrounding the perimeter of the module entrance, and inlet duct from the module entrance to 4 meter upstream of the module entrance. The inlet nozzle floor shall be sloped to cause slurry to drain to the absorber. The inlet nozzle shall also include an inlet duct hood that projects a minimum of 0.5 meter into the absorber on the top side of the inlet duct to prevent slurry from entering the inlet duct. Design the hood with a drainage system to route slurry around the module entrance. Construct the inlet duct hood of the same materials as the rest of the inlet nozzle.

3.07.14 Connections:


VOL-II-I-SEC-I - 26

DCPL-11Z02

3.07.14.01 Provide flanged connections for all instruments and piping interface points on the absorber. Connection piping and flanges shall be the same material as the absorber.

3.07.14.02 Module inlet and outlet flue gas connections shall be round, square or rectangular flanged connections. Expansion joint bolt holes shall be on maximum 150 mm centers.

3.07.14.03 Provide connections as required and as specified.

3.07.15 Access:

3.07.15.01 Provide access doors in sufficient number to allow entry into all areas of the absorber including absorber inlet and outlet nozzles, recycle spray nozzles and headers, perforated trays (if provided), absorber quench header, mist eliminators and mist eliminator spray levels. Access shall be adequate to allow removal of internals, nozzles, pipe, mist eliminators, etc. Provide means for maintenance personnel to access the recycle spray nozzles on all spray headers. The means of providing access to the nozzles on the bottom header shall allow workers access to the nozzles from a temporary work platform without requiring drainage of the reaction tank.

3.07.15.02 Provide a permanent rail-type barrier system at the absorber inlet and absorber outlet ducts for personnel protection.

3.07.15.03 Provide permanently installed supports for a temporary integrated work platform designed to be installed in the absorber below the bottom spray header. Provide a temporary work platform that can be installed by two workers in less than 8 hours. The platform shall be capable of supporting ladders, workers, tools and equipment necessary to perform maintenance on the absorber system. The platform shall be designed to store in a compact area near the absorber access entrance. Work platform shall be designed in accordance with applicable sections of the Occupational Safety and Health Standards Subpart D – Walking-Working Surfaces, 29 CFR 1910, Subpart D (Current Edition). The platform section shall be lightweight (FRP, etc.) and shall be easily carried by one person. The platform design shall be approved by Owner.

3.07.15.04 Provide safety lugs for hanging protection net required during maintenance. Provide a safety net in accordance with applicable sections of Occupational Safety and Health Regulations for Construction; Personal Protective and Life Saving Equipment, 29 CFR Part 1926 Section 1926.502.C – Safety Net Systems (Current Edition).

3.07.16 Materials of Construction:

3.07.16.01 Use materials of construction suitable for the intended service and designed to provide service for the anticipated life of the Air Pollution Control System. Specified materials shall be considered as a minimum requirement. Contractor shall supply suitable material proven to be acceptable in this service given the physical and chemical operating conditions. Materials of construction shall be suitable for continuous operation at 20,000 ppm chlorides.

3.07.16.02 All materials of construction shall be subject to approval by the Owner.

3.07.16.03 Absorber materials of construction shall be suitable for the service.


VOL-II-I-SEC-I - 27

DCPL-11Z02

a. Absorber module from base through mist eliminator section – solid 25 percent chromium duplex ferritic-austenitic stainless steel alloy 255, (UNS S32550).

b. Absorber inlet nozzle (including wet/dry interface zone) – solid Alloy C-276 (UNS N10276).

c. Absorber module above final stage mist eliminator, outlet transition, and outlet nozzle – roll clad Alloy C-276.

d. Absorber inlet nozzle turning vanes, internal bracing (only if needed), and end flanges – solid Alloy C-276.

e. Absorber reaction tank – solid 25 percent chromium duplex ferritic-austenitic stainless steel (UNS S32550) or suitable alloy with equivalent or better corrosion resistance, as approved by Owner.

f. Absorber outlet ductwork – roll clad Alloy C-276.

g. Absorber outlet ductwork turning vanes, internal bracing (only if needed), liquid collection gutters, and end flanges – solid Alloy C-276.

h. Drain connections and piping for liquid collection associated with the absorber outlet ductwork, nozzle, and module – solid Alloy C-276.

i. Absorber quench header – solid Alloy C-276 or suitable alloy with equivalent or better corrosion resistance, as approved by Owner.

j. Internal absorber recycle header and mist eliminator support beams, brackets, and attachments – solid 25 percent chromium duplex ferritic-austenitic stainless steel (UNS S32550).

k. Ductwork expansion joint frames, bolts, nuts, and washers associated with the absorber inlet awning and the absorber outlet ductwork – solid Alloy C-276.

l. Nozzles and flanges attached to the absorber module – solid 25 percent chromium duplex ferritic-austenitic stainless steel (UNS S32550).

m. Nozzles and flanges attached to the absorber inlet nozzle and outlet ductwork – solid Alloy C-276.

3.07.16.04 All remaining areas of absorber, from the base, through mist eliminator section, shall be fabricated of solid Alloy 255 or suitable alloy with equivalent or better corrosion resistance as approved by the Owner.

a. All bolting materials, nuts, washers, shall be UNS N10276 iron-nickel-chromium-molybdenum alloy in accordance with ASTM B574 or suitable alloy with equivalent or better corrosion resistance as approved by the Owner.

b. External horizontal stiffeners on clad carbon steel shall be carbon steel. External horizontal stiffeners on solid Alloy C-276 and solid Alloy 255 shall be Type 304 stainless steel. Drill drain holes in horizontal stiffeners that otherwise would collect and hold liquid.

3.07.16.05 All internal supports, braces, etc. shall be solid nickel alloy or duplex stainless steel material that matches the inside surface material of the absorber or duct in which they are installed.


VOL-II-I-SEC-I - 28

DCPL-11Z02

3.07.17 Absorber Quench Header:

3.07.17.01 Provide emergency quench header in the inlet nozzle ductwork to lower temperature of flue gas entering the absorber during upset conditions so that physical damage or decreased service life to the absorber module and related components, and Owner’s stack liner, does not occur.

3.07.17.02 The absorber inlet quench system shall be designed to operate upon loss of recycle pump flow or failure of the steam generator’s air pre-heater.

3.07.17.03 The absorber inlet quench system shall provide adequate liquid flow to saturate the maximum gas flow at all conditions. The source of this absorber quench water supply shall be the service water or fire protection system.

3.07.17.04 The absorber inlet quench system shall be designed to be non-plugging.

3.07.17.05 Location of absorber inlet quench header and spray nozzles shall be placed to avoid or minimize interference with the proper operation of the recycle spray header and related nozzles.

3.07.17.06 The absorber inlet quench system shall be designed with only the quench header exposed to flue gas. Quench header and piping connections shall be flanged for maintenance.

3.07.18 Contacts for the following alarm points shall be provided, as a minimum:

3.07.18.01 High/low reaction tank pH.

3.07.18.02 High/low reaction tank density.

3.07.18.03 High/low reaction tank level.

3.07.18.04 Reaction tank agitation system trip.

3.07.18.05 Recycle pump high bearing temperature.

3.07.18.06 Recycle pump high lube oil temperature.

3.07.18.07 High/Low agitation system amps.

3.07.18.08 High/low recycle pump amps.

3.07.18.09 High/low oxidation air pressure.

3.07.18.10 High/low oxidation air temperature.

3.08.00 MIST ELIMINATORS:

3.08.01 General:

3.08.01.01 The mist eliminator wash system shall be designed to minimize the potential for mist eliminator pluggage throughout the design operating ranges for the FGD System. Wash system design shall be capable of cleaning mist eliminators during upset conditions of calcium sulfate saturation in absorber liquor, poor limestone utilization, and high dissolved calcium concentrations in liquor entering the mist eliminator.

3.08.01.02 The mist eliminator wash control system shall be automatic and allow for wide variations in wash cycle timing and wash duration.

3.08.01.03 Design wash system to minimize number of control valves.


VOL-II-I-SEC-I - 29

DCPL-11Z02

3.08.01.04 System shall be designed to supply water to fixed grid sprays at the required flow and pressure determined by Contractor.

3.08.01.05 System shall be designed to allow the wash cycles and sequences to be easily modified, such that the optimum wash rates can be determined and set based on operational requirements.

3.08.01.06 The Mist Eliminator Wash Tanks and Pumps shall be enclosed. Provide one Mist Elinimator Wash Tank and two Mist Elinimator Wash Pumps minimum.

3.08.02 Design:

3.08.02.01 Mist eliminators shall be vane-type constructed of FRP or polysulfone high temperature thermoplastic, with a slick surface finish consistent with ASTM D4385, Level I surface finish.

3.08.02.02 Mist eliminators shall be capable of withstanding 150oCcontinuously and excursions up to 200oC for short durations (30 minutes) without permanent damage.

3.08.02.03 Solids and moisture droplet carry-over from the FGD System shall be minimized through the use of a vane type mist eliminator.

3.08.02.04 Mist eliminators shall be of the vertical flow design located in the top of the FGD SO2 absorber module above the final spray level.

3.08.02.05 At least two stages of mist eliminator media shall be provided.

3.08.02.06 The mist eliminators shall be furnished complete with assembly hardware, support materials, hold-down clips, blanking plates, bolting materials, nuts, and washers.

3.08.02.07 Design shall provide for adequate drainage of collected liquid without re-entrainment.

3.08.02.08 The mist eliminator design shall provide for easy cleaning. Designs that allow the blade sections to be easily disassembled shall be provided.

3.08.02.09 Blade sections shall be designed so that the largest sections will fit through the access doors provided. Sections shall be designed for ease of handling and installation.

3.08.02.10 Mist eliminators shall be of durable sturdy construction, capable of withstanding high-pressure type water washing. Design shall be such that blades and mist eliminator sections do not flutter or vibrate during operation.

3.08.02.11 For structural integrity, design each independently supported mist eliminator section to withstand a pressure drop at least five times the guaranteed absorber module pressure drop at maximum gas flow or an evenly distributed weight equivalent to complete pluggage with 725 kg/m2 material, whichever is greater. Blade surface shall also be capable of supporting a 225 kg

concentrated load, as might be experienced during inspections, while fully plugged with solids. Provide anchors, spacers and supports to securely hold mist eliminators and prevent shifting during operation.

3.08.03 Mist Eliminator Wash System:

3.08.03.01 The mist eliminator wash system shall be a fixed grid type.


VOL-II-I-SEC-I - 30

DCPL-11Z02

3.08.03.02 Mist eliminator spray headers and nozzles internal to the absorber shall be FRP and piping supports shall be fabricated in accordance with this Section.

3.08.03.03 Mist eliminator wash system shall be designed and installed to permit washing all required sections including the top and bottom of mist eliminator sections. During normal operation the bottom and top of the first stage mist eliminator and the bottom of the second stage mist eliminator shall be washed on a frequent basis. Provide a header for manually washing the top of the second stage mist eliminator on an infrequent basis as required.

3.08.03.04 Mist eliminator wash nozzles shall be as follows:

a. Solid cone or square type with uniform distribution.

b. Have male screw connections.

c. Nozzle connections to wash headers shall be by threadolets. Threadolets shall be welded to wash headers using full-penetration weld after grinding a bevel around the hole in the wash header pipe.

d. Have a minimum free passage of 6 mm.

e. Designed to maximize free passage to prevent plugging.

f. Designed for ease of cleaning.

g. Alternate nozzle designs to simplify piping systems, improve system performance, and/or reduce maintenance requirements are acceptable, subject to review and approval by Owner.

3.08.04 Mist Eliminator Support System:

3.08.04.01 The design of the mist eliminator support system shall be based on the following loads:

a. Dead load: The actual chevron load or 300 kg/m2 uniform load on the beam supports at each level, whichever is greater.

b. Live loads:

(1) Evenly distributed weight equivalent to complete pluggage of each mist eliminator level with 725 kg/m2 material.

(2) 225 kg point load at the center point between two beam supports to allow for walking directly on bulk entrainment and/or mist eliminator sections.

c. If the wash system is to be held up by these supports, these loads must also be included in the design.

3.08.04.02 Design to AISC allowable stresses. Maximum allowable bending stress for support members shall be 60% of the yield strength at 175oC.

3.08.04.03 Maximum allowable deflection for the support members shall be L/360.

3.08.04.04 Support beams for the mist eliminator sections shall be deep web girders or I-beam design. Supports shall be solid duplex stainless steel material that matches the inside surface material of the absorber walls where the mist eliminators are located.

3.08.04.05 If deep web girders are furnished, provide field splices with erection bolts. Splices shall be designed as complete-penetration butt joints.


VOL-II-I-SEC-I - 31

DCPL-11Z02

3.08.04.06 Provide access openings through all deep web girders.

3.08.05 Description of Operation:

3.08.05.01 The wash water pumps supply wash water to the module wash water headers which are used to keep the mist eliminator chevron vanes clean.

3.08.05.02 The mist eliminator wash cycle will normally be initiated automatically through the control system. The operator will also have the capability to initiate the sequence through the control system. Wash water control valves will automatically sequence through the module to complete the cycle. Wash frequency duration and sequence will be adjustable.

3.08.05.03 Wash cycle controls will be interlocked with reaction tank level and the absorber in service.

3.08.05.04 Service water will be used for mist eliminator wash tank makeup.

3.08.05.05 Mist eliminator wash water flow and pressure shall be monitored by the DCS control system.

3.08.05.06 Wash pumps will be started automatically. Should a pump fail, the spare pump will be started by the operator after the appropriate valves are manually adjusted.

3.08.05.07 The mist eliminator wash system shall be designed to protect the mist eliminators by starting all mist eliminator wash pumps and opening all mist eliminator wash valves on the affected absorber in the event of loss of all recycle pumps (if required for absorber design).

3.08.05.08 The mist eliminator wash system control valves shall be designed to fail in place on loss of control air pressure or control power.

3.08.05.09 Wash pumps will automatically trip on low mist eliminator wash tank level.

3.08.05.10 The following alarms will be provided as a minimum:

a. Low/high mist eliminator wash tank level.

b. Low system wash water pressure.

c. High system wash water pressure.

d. Low system wash water flow.

e. Sequence failure.

f. Mist eliminator wash pump trip.

g. Mist eliminator wash pump high motor amps.

h. Mist eliminator wash pump high motor temperature.

i. Mist eliminator service air pressure low.

3.09.00 RECYCLE SPRAY HEADERS AND NOZZLES:

3.09.01 Provide dedicated spray header for each recycle pump.

3.09.02 All connections shall be flanged.

3.09.03 Spray header piping shall have flanged connections for maintenance.


VOL-II-I-SEC-I - 32

DCPL-11Z02

3.09.04 Locate bottom header such that the spray pattern does not spray into the inlet duct during low flue gas flow conditions. The nozzle outlets for adjacent spray levels shall be separated by a minimum of 1.5 meters. Locate top spray header at a minimum of 1.8 meters below bottom of mist eliminator.

3.09.05 The first spray header above the tray shall be located such that the spray nozzle outlet is a minimum of 1.5 meters above the tray.

3.09.06 Recycle spray nozzles shall be as follows:

3.09.06.01 Right angle hollow cone type, one-piece construction.

3.09.06.02 Fabricated of silicon carbide refractory material.

3.09.06.03 Victaulic type couplings with Alloy C-276 fasteners.

3.09.06.04 Nozzles shall have a minimum 50 mm free passage to minimize pluggage potential.

3.09.07 Spray headers inside the absorber shall be the same material that match the inside surface material of the absorber where they are located and shall be self-supporting such that no internal hangers, brackets, supports, etc., are required.

3.09.08 Each spray level shall be designed to provide complete saturation of the flue gas and provide 100% spray coverage at a maximum of 1 meter below the nozzle. Provide overlapping coverage within each spray level as necessary to meet this requirement. Voids in the slurry coverage, where flue gas can pass through the spray level without contacting the slurry, are not acceptable.

3.09.09 Contractor shall provide a drawing showing the spray coverage for each spray level at the Contractor’s design distance below each spray level for maximum spray coverage. Each drawing shall indicate the elevation depicted in the drawing and the distance between the spray level shown and plane of the respective drawing. One drawing shall be provided for each spray level. For FGD SO2 absorbers designed with a perforated plate, the Contractor shall also provide a cross section of the absorber indicating the perforated plate, any dividers and the spray coverage for each spray level above and below the perforated plate.

3.10.00 PERFORATED TRAYS (IF PROVIDED):

3.10.01 Tray Material:

3.10.01.01 Tray material shall be solid nickel alloy material that matches the inside surface material of the absorber at the location where they are installed.

3.10.01.02 Trays shall be bolted to the tower. Each bolting set shall include a hex head bolt with hex nut and washer.

3.10.02 Fabrication:

3.10.02.01 Maximum deviation of main flat portion of each fabricated tray from a true flat surface shall not exceed 6 mm at any point. The main flat portion of each tray is the area inside the perimeter defined by the bolt holes.

3.10.02.02 Perforations shall be round openings. Dimensional tolerances on openings and bars shall conform to ASTM E674. Holes shall be punched so that when tray fabrication is complete the punch side is the bottom surface of the tray.


VOL-II-I-SEC-I - 33

DCPL-11Z02

After perforation is completed, a deburring operation shall be performed on the die side of each plate to remove burrs formed during perforation.

3.10.02.03 Punch shall be of a material that will not contaminate the plate material.

3.10.02.04 Tolerance on bolt hole locations shall be maintained within 1.5 mm. Deburr all bolt holes after punching.

3.10.02.05 Bend and form the perforated sheets after completion of all other fabrication operations.

3.10.02.06 Support and reinforce plates as required to provide a rigid surface that will not move, warp or deflect excessively. Plates shall support loads of sludge, 300 mm deep, formed during upset conditions plus maintenance personnel and equipment required to remove the sludge. Maximum allowable deflection shall be L/360.

3.11.00 REACTION TANK:

3.11.01 General:

3.11.01.01 The Reaction Tanks shall be integral with the absorber module (common vessel).

3.11.01.02 The Reaction Tanks shall be all welded construction and be designed and constructed in accordance with API 650.

3.11.01.03 The Reaction Tanks shall be designed to withstand all operating conditions (temperature, pressure, corrosion, abrasion, agitation, etc.) within the tank.

3.11.01.04 The Reaction Tanks shall be cylindrical.

3.11.01.05 The Reaction Tank floors shall be sloped 1% to clean out doors.

3.11.01.06 Each reaction tank shall provide a minimum solids residence time of 12 hours and a minimum liquid residence time of 5 minutes, whichever is more stringent. Solids residence time shall be calculated for each design operating condition.

3.11.01.07 Beams, stiffeners, etc., for the Reaction Tanks shall be located external to tank such that inside of tank is smooth flat plate. External structural members shall be constructed of Type 304 stainless steel. Provide drain holes in horizontal stiffeners that otherwise would hold and collect liquid.

3.11.01.08 Venting flue gas from the reaction tanks to the atmosphere is prohibited.

3.11.01.09 The Reaction Tanks shall be designed for a minimum of 1.2 times the design specific gravity of the liquid, as determined by the Contractor. Walls shall be designed for full hydrostatic head at the level of the tank overflow.

3.11.01.10 The Reaction Tanks shall be provided with a grade level access door of sufficient size for the entry of rubber-tired excavation equipment into the tank during cleanout operations. The Reaction Tanks shall be designed to withstand normal mechanical abuse and vehicle and equipment loads from this activity. The Contractor shall coordinate the door size with the Owner, to assure meeting this condition.

3.11.01.11 Provide reaction tanks with side entering agitators of adequate size to maintain the suspension of all solids. Reaction tanks shall be provided with baffles as recommended by the agitator manufacturer.


VOL-II-I-SEC-I - 34

DCPL-11Z02

3.11.01.12 The reaction tank and agitation system shall be designed to achieve the specified oxidation levels. Oxidation air shall be introduced to the reaction tank using an injection port type oxidation system. Designs that include internal oxidation air spargers or piping that needs internal tank supports are not acceptable.

3.11.02 Connections:

3.11.02.01 Provide instrument connections for each reaction tank for all instrumentation provided.

3.11.02.02 Provide 150 lb (minimum) flanged connections for recycle pumps, overflow, bleed pumps, oxidation air, limestone slurry, gravity drain, hydrocyclone/ thickener overflow return, reclaim water piping, and all other required piping.

3.11.02.03 Provide clear access for FGD SO2 absorber bleed piping.

3.11.02.04 Provide a gravity overflow connection on each reaction tank. Overflow shall be designed to prevent venting of flue gas and siphoning of slurry from the reaction tank.

3.11.03 Cleanouts, Access and Manholes (per reaction tank):

3.11.03.01 Provide one 600 mm x 600 mm flanged clean-out opening flush with bottom per API 650.

3.11.03.02 Provide at least one flanged manhole with davits on side of manhole. Clean out openings are not considered as access.

3.11.04 Tank Grounding: Provide four tank grounding connections equally spaced around each tank perimeter.

3.11.05 Reaction Tank Sampling and Analysis:

3.11.05.01 Provide a dedicated sample/analysis piping loop to facilitate on-line reaction tank analysis and grab sampling as follows:

a. Continuously recirculate a slurry stream through the sampling loop with discharge back to the reaction tank to provide a measurable stream, representative of reaction tank contents.

b. Provide the necessary arrangement of valves and parallel piping to facilitate using either of two redundant density instruments, each installed on a different recycle pump (if required for absorber design). The design shall include the means for alternating between the two instruments, and isolating one for maintenance with the other in service.

c. Provide an insertion-type pH probe.

d. Provide slurry sample connection in the vicinity of the pH probe to permit intermittent "grab sampling" for detailed analysis. The grab sample valve and sample discharge shall be no more than 1.5 meters above a main access level. Provide a stainless steel sample sink directly under the sample connection for the collection of excess slurry and all piping and connections necessary to return the excess slurry to the absorber area trench. Provide a service water connection with valve and faucet at the sample sink. Provide a 600 mm x 900 mm work area for sample preparation and instrument maintenance adjacent to the sample sink. Provide enclosed water-tight lockable storage under the work area for secure storage of equipment and tools. The interior volume of the


VOL-II-I-SEC-I - 35

DCPL-11Z02

lockable storage unit shall be 1 cubic meter minimum. Provide an electrical circuit suitable for the service and environment to power a vacuum pump and portable instruments and equipment. Provide overhead lighting for the area. Provide an eye wash station at a location approved by Owner. Protect the area from wash-down and tank overflows if necessary.

e. Contractor shall design the FGD System to maintain slurry linear velocity past installed instruments greater than 1.5 m/sec, but less than 2.5 m/sec.

3.11.05.02 Sample/analysis piping systems shall be designed to accommodate the specific requirements of the installed instruments, per the manufacturers' recommendations as well as the ability to gather manual samples of the absorber recycle slurry. Requirements of the instruments include, but are not limited to:

a. Ensuring that operating density instruments are completely filled with process fluid.

b. Ensuring that idle density instruments can be completely drained and placed into the manufacturer-recommended standby condition.

c. Ensuring that pH probes are continuously immersed in process fluid.

d. Alternately, the pH probes may be located in the recycle pump suctions (if required for absorber design). A minimum of two probes shall be provided. Provisions shall be included so each probe can be easily relocated to another pump should a pump be out of service. Provide slurry sample connections to meet the requirements specified above.

3.12.00 REACTION TANK AGITATION SYSTEM:

3.12.01 Coordinate design and location with recycle pumps, recycle piping, oxidation air injection systems and the design of the reaction tank.

3.12.02 Design the reaction tank agitation system to:

3.12.02.01 Keep solids from settling to the tank bottom with all absorber pumps shutdown.

3.12.02.02 Be capable of resuspending settled solids after a period of 24 hours with all absorber pumps shutdown and all agitators off-line.

3.12.02.03 Agitation system shall be as specified.

3.12.02.04 Provide a tank agitation model study to confirm system design.

3.12.02.05 Provide a complete agitation system incorporating results from the agitation system modeling results.

3.12.03 Reaction tank agitation system shall be capable of a remote start from the DCS or locally by the FGD System operator.

3.12.04 The agitation system controls shall include a system trip upon an alarm for low reaction tank level.

3.13.00 RECYCLE PUMPS:

3.13.01 Contractor shall furnish recycle pumps of the number, size and capacity necessary to optimize the absorption system design. The maximum capacity


VOL-II-I-SEC-I - 36

DCPL-11Z02

of a recycle pump shall be 4000 liters/sec. The design shall include one installed spare pump and spray level. The performance guarantees shall be met with any pump/spray level out of service. Minimum number of recycle pumps shall be four.

3.13.02 The absorber module shall be capable of continuous operation with one, or all, recycle pumps in operation (including the spare), or any combination of recycle pumps.

3.13.03 Recycle pumps shall have a vertical discharge and shall be provided with a dedicated spray header such that the pump discharge is not interconnected with any other pump discharge.

3.13.04 Recycle pumps shall be high-chrome alloy slurry pumps.

3.13.05 Each pump shall have its own dedicated suction line with a motor-actuated suction isolation valve located as close as possible to the reaction tank.


VOL-II-I-SEC-I - 37

DCPL-11Z02

3.13.06 Recycle pumps shall be individually controlled. The FGD System operator shall be able to manually initiate start and stop sequences, as needed for online maintenance or operational control. Following a manually initiated start, the recycle pumps shall start automatically after proper valve positioning is confirmed.

3.13.07 Recycle piping and pumps shall be automatically drained upon shut down to prevent settling of solids in the piping and equipment. Permanent piping and valve shall be provided so the operator can manually flush piping and pumps on shutdown.

3.13.08 Recycle pumps shall trip on a low reaction tank level alarm. Adequate tank level and agitator operation shall be a start permissive.

3.13.09 Recycle pump motor amps shall be continuously monitored and reported to the FGD System control system.

3.13.10 The FGD System shall be designed to allow shutdown of one or more recycle pumps when the absorber module is operating at reduced gas flows or reduced inlet sulfur dioxide loadings. The FGD System shall also be capable of continuous operation with any recycle pump running. The Contractor will not be allowed to designate which pump is the standby spare.

3.14.00 OXIDATION AIR INJECTION SYSTEM:

3.14.01 Provide two (2), each 100% capacity, centrifugal type blowers. Blowers shall be installed in sound-mitigating and ventilated enclosures by this Contract.

3.14.02 Blowers shall be designed for operating and transient conditions as specified for the ductwork.

3.14.03 Margins for the oxidation air blowers shall be as follows:

3.14.03.01 Design capacity of the blower system shall be 120% of maximum air demanded.

3.14.03.02 Design static pressure shall be 130% of the static pressure required to deliver the air to the absorber at the maximum rating of the Unit.

3.14.04 Design capacity and design static pressure shall be calculated at an inlet air temperature equal to the maximum specifeid ambient air temperature.

3.14.05 Design injection piping so that it does not plug on deenergization of the agitators and/or oxidation air blowers. Injection piping shall be a minimum height of 600 mm above the reaction tank floor. If holes in injection piping are utilized, locate holes on the pipe bottom so that slurry drains out of the pipe into the reaction tank.

3.14.06 Oxidation air piping interior to the absorber and exterior of the absorber upto the reaction tank liquid level shall be Alloy 255 (UNS 32550).

3.14.07 The injection piping and agitator designs shall be coordinated to achieve appropriate air distribution in the reaction tank with the recycle pumps in or out of service.

3.14.08 Injection piping shall be flanged to expedite removal.

3.14.09 Oxidation air supply piping shall be flanged to expedite removal.


VOL-II-I-SEC-I - 38

DCPL-11Z02

3.14.10 Oxidation air piping shall include provisions for external cleanout, washing, and flushing with the unit on-line.

3.14.11 The reaction tank and agitation system shall be designed to achieve the specified oxidation levels. Oxidation air shall be introduced to the reaction tank using an injection port type oxidation system. Designs that include internal oxidation air spargers or piping that needs internal tank supports are not acceptable.

3.14.12 Oxidation air shall be saturated with service water prior to injection.

3.15.00 LIMESTONE SLURRY PUMPS:

3.15.01 Provide two 100% capacity limestone slurry transfer pumps for each limestone slurry loop.

3.15.02 Pumps shall operate in a continuous transfer loop from the limestone slurry feed tank to the absorber reaction tank and back to the limestone slurry feed tank.

3.15.03 Pumps shall be sized to comply with specified pipeline velocities everywhere in the transfer system, including the return line to the limestone slurry tank, while operating under any unit load condition.

3.15.04 A pressure control valve or orifice (if required) shall maintain system pressure. Pressure shall be monitored downstream of takeoff to the reaction tank.

3.15.05 One pump serves as a standby spare and shall be started by the operator if the primary pump trips or fails to start.

3.15.06 Pumps shall have automatic start and shutdown sequences initiated by the operator, wherein suction and discharge valves automatically open and close as required for the particular sequence. Proper valve position shall be established before the pumps can be started.

3.15.07 Pumps shall automatically trip on low tank level.

3.16.00 LIMESTONE SLURRY TANK AND AGITATORS:

3.16.01 General:

3.16.01.01 Tank level shall be continuously monitored.

3.16.01.02 The agitator(s) shall operate continuously in order to maintain solids suspension.

3.16.01.03 Agitator shall trip on low level in limestone slurry tank.

3.16.02 Alarm Points: The following alarm points shall be provided as a minimum:

3.16.02.01 Pump trips.

3.16.02.02 Low/High limestone slurry tank level.

3.16.02.03 Low/High limestone slurry tank density.

3.16.02.04 Agitator trip.

3.16.02.05 Low limestone slurry pump discharge pressure.

3.16.02.06 Pump start-up sequence failure.


VOL-II-I-SEC-I - 39

DCPL-11Z02

3.16.03 Instrumentation:

3.16.03.01 Pressure Gauges.

3.16.03.02 Pressure Transmitter.

3.16.03.03 Level Element/Switch.

3.16.03.04 Level Element, Indicator and Transmitter.

3.16.03.05 Density Element and Transmitter.

3.16.03.06 Flow Element and Transmitter.

3.16.03.07 Pressure Switch.

3.16.03.08 Temperature Indicator and Transmitter.

3.16.03.09 Current Transmitter.

3.17.00 RECLAIMED WATER SYSTEM:

3.17.01 Reclaim Water Tank:

3.17.01.01 Provide one (1) Reclaim Water Tank. The Contractor shall determine the appropriate live storage capacity required for proper operation.

3.17.01.02 Provide top-entering agitator(s) for the Reclaim Water Tank.

3.17.01.03 Provide a service water supply to each RW Tank to automatically maintain minimum tank level.

3.17.02 Reclaim Water Feed Pumps:

3.17.02.01 Provide two (2) 100 percent capacity Reclaim Water Feed Pumps per Reclaim Water Tank. The Contractor shall determine the appropriate pump capacity required for proper operation.

3.17.02.02 Reclaim Water Feed Pumps shall be of type and materials of construction suitable for the expected conditions and duty.

3.17.02.03 Reclaim Water Feed Pumps’ piping shall arranged so that either Reclaim Water feed pump can operate individually or both can operate simultaneously.

3.18.00 ABSORBER BLEED:

3.18.01 Provide sampling isolation valves in the absorber bleed discharge line.

3.18.02 The sample valves and sample discharges shall be no more than 5 feet above a main access level. Provide an 450 mm by 450 mm stainless steel sample sink directly under each sample connection for the collection of excess slurry and all piping and connections necessary to return the excess slurry to the absorber area trench. Provide a service water connection with valve and faucet at the sample sink. Provide a 600 mm by 900 mm work area for sample preparation and instrument maintenance near the sample sink. Provide enclosed water-tight lockable storage under the work area for secure storage of equipment and tools. The interior volume of the lockable storage unit shall be 1 cubicn meter minimum. Provide an electrical circuit suitable for the service and environment to power a vacuum pump and portable instruments and equipment. Provide overhead lighting for the area. Provide


VOL-II-I-SEC-I - 40

DCPL-11Z02

an eye wash station at a location approved by Owner. Protect the area from wash-down and tank overflows if necessary.

3.18.03 Absorber Bleed Pumps:

3.18.03.01 Provide two- 100 percent capacity bleed pumps.

3.18.03.02 A dedicated suction line shall be provided for each pump with a motor-actuated suction isolation valve located as close as possible to the Absorber Reaction Tank.

3.18.03.03 Absorber Bleed pumps shall be metal-lined slurry pumps.

3.18.03.04 Bleed pumps and piping shall automatically drain on pump shutdown.

3.18.03.05 A flush connection to flush the bleed piping and pumps shall be provided and piped to the service water system.

3.19.00 PIPING AND VALVES:

3.19.01 Ball Mill System and Limestone Slurry:

3.19.01.01 Provide one dedicated limestone slurry transfer loop from the limestone slurry storage tank to the absorber.

3.19.01.02 Slurry lines shall be sized to maintain a minimum of 1.5 m/s to prevent settling of solids and a maxium of 2 m/s velocity to minimize wear due to abrasion.

3.19.01.03 Easily removable sections of piping shall be provided at equipment connections to facilitate maintenance operations.

3.19.01.04 Provide isolation valves to facilitate pump and equipment maintenance without interrupting system operation.

3.19.01.05 Provide minimum 50 mm flush line connections.

3.19.01.06 Provide expansion joints at all equipment connections and as required to accommodate thermal movement.

3.19.01.07 Each slurry line and pump shall be automatically flushed and drained when a pump shuts down. Flush time shall be adjustable.

3.19.01.08 Slurry lines shall be sloped to drain. Provide manual flush connections, high point vents and low point drains for limestone slurry transfer loop piping systems. Reclaimed water shall be piped to the flush connection. The drains shall be piped to the nearest trench.

3.19.01.09 Pumps shall have individual suction lines directly connected to the Limestone Slurry Tank.

3.19.02 Absorber and Absorber Bleed Systems:

3.19.02.01 Provide absorber recycle piping as required to interconnect reaction tanks, recycle pumps and recycle spray headers for each absorber.

3.19.02.02 Piping shall be sized to keep solids in suspension while at the same time minimizing wear due to abrasion. Velocity shall be limited to 1.5 to 2.5 m/sec in recycle lines and headers.

3.19.02.03 Provide valves and instrument connections as specified and required.

3.19.02.04 Provide motor actuated knife gate valves on each recycle pump suction line.


VOL-II-I-SEC-I - 41

DCPL-11Z02

3.19.02.05 Provide easily removable sections of pipe at pumps and at absorber spray header connections to facilitate maintenance operations.

3.19.02.06 The pump supply piping shall be arranged such that any of the pumps can be isolated and maintained while the absorber is operating. Absorber recycle pump discharge piping design shall include a means (such as a blanking plate) a positive seal to prevent flue gas from entering an isolated recycle pump piping when a pump is isolated for maintenance.

3.19.02.07 Expansion joints shall be installed at each recycle pump suction and discharge flange, at each absorber module spray header connection and additional locations as required to accommodate thermal expansion of piping and module and to isolate the piping from the absorber vessel and equipment vibrations.

3.19.02.08 Provide minimum 100 mm flanged drain connections to drain recycle lines on recycle pump trip or shut down. Valves and piping to control and convey drainage to the absorber area trench drainage system shall be provided and installed by the Contractor.

3.19.02.09 Provide flanged flush water piping connections at the discharge of each pump.

3.19.02.10 Provide a sample connection complete with valves and piping on each recycle pump discharge line.

3.19.02.11 Except for modulating control service, all control valves shall be line size.

3.20.00 INSTRUMENTATION:

3.20.01 Pressure gauges shall be provided at each of the following locations at a minimum:

3.20.01.01 Each recycle pump suction line.

3.20.01.02 Each recycle pump discharge.

3.20.01.03 Each recycle spray header elevation (one gauge for each spray header).

3.20.02 Local Level Indicators shall be provided at each of the following locations at a minimum:

3.20.02.01 Each reaction tank.

3.20.02.02 Each recycle pump oil level.

3.20.02.03 Each recycle pump gear box

3.20.02.04 Each reaction tank agitator gear box oil level.

3.20.03 Level Transmitters shall be provided at each of the following locations at a minimum:

3.20.03.01 Each reaction tank.

3.20.04 pH Analyzers and Transmitters shall be provided at each of the following locations at a minimum:

3.20.04.01 Each reaction Tank Sample/Analysis piping loop.


VOL-II-I-SEC-I - 42

DCPL-11Z02

3.20.05 Density Instruments and Transmitters shall be provided at each of the following locations at a minimum:

3.20.05.01 Each reaction Tank Sample/Analysis piping loop.

3.20.06 Limit Switches (Proximity Type) shall be provided for each of the following locations at a minimum:

3.20.06.01 Open/closed position of all control valves.

3.20.07 Temperature Switches shall be provided at each of the following locations at a minimum:

3.20.07.01 Each recycle pump/lube oil reservoir.


4.01.00 SUMMARY:

4.01.01 The dewatering equipment includes hydrocyclones, rotary drum vacuum filters, and supporting equipment. Furnish and deliver the following as required and specified for Flue Gas Desulfurization System:

4.01.02 Hydrocyclones shall include, but not be limited to:

4.01.02.01 Hydrocyclones.

4.01.02.02 Inlet manifold assembly.

4.01.02.03 Overflow and underflow launders.

4.01.02.04 Support structure.

4.01.02.05 Piping and valves.

4.01.02.06 Linings and coatings.

4.01.03 Rotary drum vacuum filters shall include:

4.01.03.01 Filter drums.

4.01.03.02 Slurry vats.

4.01.03.03 Agitators.

4.01.03.04 Filter cloths.

4.01.03.05 Vacuum pumps.

4.01.03.06 Vacuum receivers.

4.01.03.07 Filtrate pumps.

4.01.03.08 Support frames and base plates.

4.01.03.09 Electric motors and couplings.

4.01.03.10 Piping and valves.

4.02.00 REFERENCES:

4.02.01 Design, fabricate, assemble, and test equipment and materials in accordance with manufacturer's recommended procedures and following applicable codes and standards.


VOL-II-I-SEC-I - 43

DCPL-11Z02

4.02.01.01 American Gear Manufacturer’s Association (AGMA).

4.02.01.02 American Iron and Steel Institute (AISI):

a. Carbon Steel: Hot-Rolled and Cold Finished Bars.

4.02.01.03 American Society for Testing and Materials (ASTM).

4.02.01.04 American Welding Society (AWS).

4.02.01.05 Anti-Friction Bearing Manufacturers Association (AFBMA):

a. 9 - Load Ratings and Fatigue Life for Ball Bearings.

b. 11 - Load Ratings and Fatigue Life for Roller Bearings.

4.02.01.06 Institute of Electrical and Electronic Engineers (IEEE).

4.02.01.07 National Electric Manufacturers Association (NEMA).

4.02.01.08 Occupational Safety and Health Administration (OSHA)

4.02.01.09 Society for Protective Coatings (SSPC).

4.02.01.10 Standards of the Hydraulic Institute 14th Edition.

4.03.00 SUBMITTALS:

4.03.01 Complete manufacturer’s data and detailed drawings for all equipment and material which shall include complete descriptive data to define materials, size, capacities, manufacturer, type, model, accessories, terminal points, operational features, etc.

4.03.02 The Contractor shall submit for approval complete wiring diagrams and control schematics with terminal information.

4.03.03 The Contractor shall submit a complete material balance for the overall gypsum dewatering system.

4.03.04 Provide power requirements of all electrical devices.

4.03.05 Instruction manuals, complete with operating and start-up procedures, maintenance procedures, and control logic.

4.03.06 Contractor shall submit for approval complete piping and instrument diagrams including sufficient detail to identify all required instrumentation and control loops for start-up, shutdown and normal operation for all systems and subsystems that comprise the overall Gypsum Dewatering System.

4.03.07 Recommended spare parts list with an estimated frequency of replacement and unit pricing.

4.03.08 List of operational tests and analyses that must be performed during normal operation of the equipment.

4.03.09 Foundation loads including static and dynamic loads (equipment capacity and operating weights). Foundation loads shall include all loads for start-up, operating and shutdown conditions. Anchor bolt requirements including location, size, and projection of all anchor bolts.


VOL-II-I-SEC-I - 44

DCPL-11Z02


4.04.01 All Equipment and appurtenances of the Gypsum Dewatering system (including all subassemblies there of) shall have an acceptable history of satisfactory reliable service in central station use for a period of at least three years at comparable temperature, pressure, and design stress levels.









4.04.04 Field Testing:

4.04.04.01 Tanks and vessels shall be field tested for tightness.

4.05.00 DELIVERY, STORAGE AND HANDLING:

4.05.01.01 Adequately crate, block, anchor and protect material for shipment. Items damaged during shipment shall be replaced without expense to the Owner.

4.05.01.02 Adequately seal and protect equipment to be stored outdoors prior to shipment. Flanged connections shall be covered with minimum ½ inch thick plywood covers bolted to the flange with not less than four bolts. All other connections shall be plugged or capped with standard pipe plugs or pipe caps.

4.05.01.03 Provide lifting lugs to facilitate loading, unloading, and installation.

4.05.01.04 Apply manufacturer's standard preservatives to protect equipment and materials during shipment and storage at the plant site. Protect all bearings with grease packing or lubrication oil.

4.05.01.05 Ship equipment as completely assembled as possible, consistent with shipping facilities and construction requirements at the Owner's plant site. Optimize shop-fabricated assemblies to reduce overall costs.

4.05.01.06 Factory tube and wire all panel boards and install control devices in panel boards wherever possible.

4.05.01.07 Protect motors, electrical equipment and machinery of all kinds against corrosion, moisture deterioration, mechanical injury, and accumulation of dirt or other foreign matter during shipment.


VOL-II-I-SEC-I - 45

DCPL-11Z02

4.05.01.08 Vacuum filters, hydrocyclones, and miscellaneous equipment shall be stored in a manner acceptable to the manufacturer. Store the vacuum system units, filter drives, motors, instruments and controls in a dry, weatherproof warehouse

4.06.00 VACUUM FILTER:

4.06.01 General:

4.06.01.01 Provide 3 – 100% capacity vacuum filters shall be provided, each sized for the gypsum production of one unit.

4.06.01.02 Vacuum filters shall be the rotary drum type.

4.06.01.03 All parts subject to heavy wear shall be designed and arranged for complete access for maintenance and/or replacement.

4.06.02 Slurry vat:

4.06.02.01 Shell and heads shall be rubber-lined ASTM A36 carbon steel, welded construction.

4.06.02.02 External frame and support members shall be ASTM A36 carbon steel.

4.06.02.03 Connections to be provided shall include:

a. Feed inlet(s).

b. Overflow(s).

c. Drain(s).

d. Cleanout port(s).

4.06.02.04 Feed inlet(s) shall provide even distribution across the vat.

4.06.02.05 Provide a continuous level transmitter for indication of liquid level.

4.06.03 Agitator:

4.06.03.01 Agitator shall be reciprocating paddle type with agitator supports fixed at the drum bearings.

4.06.03.02 Non-wetted surfaces shall be ASTM A36 welded steel plate or tubing construction.

4.06.03.03 All liquid contact surfaces shall be rubber-lined.

4.06.03.04 Adequate agitation shall be provided so as not to allow accumulation of solids in the bottom of the slurry vat.

4.06.03.05 Agitator paddles shall extend the full length of the vat.

4.06.04 Filter Drum:

4.06.04.01 Filter drum shell and heads shall be rubber-lined ASTM A36 carbon steel or 317L stainless steel, welded construction.

4.06.04.02 Provide two maintenance man ways, one on each drum head, 180° apart.

4.06.04.03 Drain lines and vacuum tubing shall be Alloy 255 or 317 L (with 3.75% Mo) stainless steel with a 1-inch minimum diameter.

4.06.04.04 Filter media shall be polypropylene fabric.


VOL-II-I-SEC-I - 46

DCPL-11Z02

4.06.04.05 Each vacuum filter system shall be provided with a separate wire winding assembly. Wire shall be synthetic type rather than metal type.

4.06.04.06 All internal surfaces for carbon steel filter drums shall be coated with a corrosion resistant epoxy coating.

4.06.05 Deck:

4.06.05.01 Drainage grid shall be injection molded polypropylene, waffle construction, snap-in type.

4.06.05.02 Division and end strips shall be molded rubber construction.

4.06.06 Valve Assembly:

4.06.06.01 Valve assembly shall be ultra-high molecular weight (UHMW) polypropylene.

4.06.06.02 Valve and drive hub bearings shall be cast iron with replaceable phenolic lining.

4.06.06.03 Wear plate shall be replaceable type of polypropylene construction.

4.06.06.04 Outlets shall include:

a. Pickup port(s) for cake formation.

b. Dewatering port(s) for cake drying.

4.06.06.05 Inlets shall include:

a. Air connection for cake blowback.

4.06.07 Drum Drive:

4.06.07.01 Provide motor complete with variable-speed drive, couplings and guards.

4.06.07.02 Provide enclosed worm gear reducer.

4.06.08 Discharge:

4.06.08.01 Designed for cake blowback and scraper discharge removal.

4.06.08.02 Scraper Assembly:

a. Shall include a polypropylene scraper blade and Alloy 255 or equivalent apron.

b. Shall be designed to allow adjustment of clearance between the scraper blade and the filter drum.

4.06.08.03 Blowback:

a. Filter shall provide for air blowback prior to scraper discharge to loosen the dried cake from the filter cloth.

b. Blowback system shall be designed to operate with 60 psig plant service air.

4.06.08.04 The gypsum handling conveyors and chute work shall by furnished by Contractor.

a. Allow adequate space for conveyor transfers and maintenance.


VOL-II-I-SEC-I - 47

DCPL-11Z02

4.07.00 VACUUM FILTER ACCESSORY SKIDS:

4.07.01 General:

4.07.01.01 Provide a shop assembled vacuum filter accessory skids for each vacuum filter.

4.07.01.02 Accessory skids shall include vacuum pumps, vacuum receivers, filtrate pumps, instrumentation, wiring, controls, piping, valves, etc.

4.07.01.03 Skid components shall be as specified below.

4.07.02 Vacuum pumps:

4.07.02.01 Vacuum pumps shall be single-stage rotary, liquid ring, vacuum pumps.

4.07.02.02 Provide one 100% vacuum pump for each vacuum filter.

4.07.02.03 Cast iron / ductile iron construction.

4.07.02.04 Impeller shall be eccentrically mounted in pump body casing and statically balanced.

4.07.02.05 Design shall include connections for continuous draining of small solid particles which otherwise could cause damage due to erosion.

4.07.02.06 Provide any screens, strainers, or accessories in seal water lines as required for plant service water characteristics.

4.07.02.07 Provide all connections and fittings as may be required by Manufacturer for diagnostic and troubleshooting the vacuum pump.

4.07.02.08 Bearings:

a. Anti-friction type rated at AFBMA 60,000-hour minimum L-10 life.

b. Oil or grease lubricated, provided with drain and fill piping to a location where bearing can be conveniently flushed, drained, and refilled; and oil level sight glasses located so they can be readily and conveniently observed.

c. Accessible with minimum pump disassembly.

4.07.02.09 Provide Gear Reducers as follows:

a. General:

(1) Gear reducer shall be parallel shaft, single reduction, and enclosed-type helical gear reducers in accordance with AGMA Standards.

(2) Selection based on a 24-hour per day continuous duty with a 2.0 service factor (times the pump demand horsepower at the design point). In no case shall the reducer thermal horsepower rating be less than the rated motor horsepower.

(3) Gear reducer units shall be identical.

b. Construction:

(1) Cast iron, cast steel or fabricated steel cases.


VOL-II-I-SEC-I - 48

DCPL-11Z02

(2) Reducer roller bearings rated at AFBMA 60,000-hour minimum L-10 life based on pump demand horsepower. Bearing seals shall be of the dual-lip seal type.

(3) Provide lifting lugs on cases.

c. Lubrication:

(1) Use oil splash type.

(2) Forced external cooling, if required, shall be provided by shaft mounted cooling fans.

d. Coupling: Use double-engagement gear type.

4.07.02.10 Furnish all accessories including soleplates for pump and motor, gear reducer coupling guard, etc.

4.07.02.11 Provide inlet and outlet manifolds for each vacuum pump. Inlet manifolds shall include integral vacuum relief device.

4.07.02.12 Each vacuum pump shall be factory tested under full load operating conditions.

4.07.02.13 Vacuum pumps shall include suction spray nozzles for condensation of saturated feed vapors.

4.07.02.14 Each vacuum pump shall include a seal water feed piping assembly including all control valves, regulators, etc. for control of seal water flow to the vacuum pump.

4.07.02.15 Provide tamper-proof seal water valves designed so that the valve position can be locked.

4.07.03 Vacuum Receivers:

4.07.03.01 Provide one vacuum receiver for each vacuum filter.

4.07.03.02 Receiver to be designed so that no liquid flow is directed to toward the receiver inlet.

4.07.03.03 Receivers shall extract greater than 99 percent of the free liquid.

4.07.03.04 Rubber-lined carbon steel construction or suitable alloy with satisfactory corrosion resistance as approved.

4.07.03.05 Provide all necessary flanged connections including:

a. Filtrate inlet(s).

b. Filtrate outlet(s).

c. Drain.

d. Vacuum outlet.

e. Vacuum gauge.

f. Glass sight gauge.

g. Additional connections as required for safety or control instrumentation.

4.07.03.06 Provide steel support legs as required.


VOL-II-I-SEC-I - 49

DCPL-11Z02

4.07.04 Water-Trap Silencers:

4.07.04.01 Provide vacuum pump exhaust water-trap silencers.

4.07.04.02 Alloy or stainless steel construction suitable for application.

4.07.04.03 Flat bottom design for mounting on accessory skid.

4.07.04.04 Vapor exhaust to be piped outside.

4.07.04.05 Provide all necessary flanged connections including:

a. Vacuum inlet.

b. Drain.

c. Vapor outlet.

d. Overflow.

e. Glass sight gauge.

f. Additional connections as required for safety or control instrumentation.

4.07.05 Filtrate Pumps:

4.07.05.01 Provide one 100% capacity filtrate pump for each vacuum filter. Furnish one complete uninstalled spare filtrate pump.

4.07.05.02 Filtrate pumps shall be end suction, single stage, and single suction type. Pumps shall be capable of continuous operation under zero flow conditions.

4.07.05.03 Type 316L stainless steel construction.

4.07.05.04 Furnish complete with base plate, coupling, and coupling guard.

4.07.05.05 Provide sampling cock.

4.08.00 INSTRUMENTATION AND CONTROLS:

4.08.01 Provide Vacuum Gauges:

4.08.01.01 Located on each filter valve outlet and vacuum pump inlet.

4.08.02 Provide Vacuum Filter Control Units:

4.08.02.01 To be mounted on vacuum filter.

4.08.02.02 Control panel to include:

a. Drum rotation speed controls with run and stop lights for each.

b. Vacuum level alarm light interconnected to vacuum gauge.

c. Alarm acknowledgement.

4.08.03 Provide Vacuum System Control Units:

4.08.03.01 To be mounted on each vacuum pump arrangement.

4.08.03.02 Control to include:

a. Vacuum pump run and stop lights with push-button operation.

b. Loss of vacuum pump seal water alarm light.


VOL-II-I-SEC-I - 50

DCPL-11Z02

c. Alarm acknowledgement.

d. Filtrate pump run and stop lights with emergency push-button operation.

4.08.04 Provide contacts wired to terminal blocks for external signals and controls.

4.08.05 All control switches shall be of the H-O-A type.

4.08.06 Enclose all electrical equipment and components in enclosures as specified.

4.08.07 Equipment shall be designed for a wet environment.

4.09.00 VALVES:

4.09.01 Valves 2 inch or larger shall be knife-gate.

4.09.02 Vat drain valve shall be air operated with local control.

4.10.00 PIPING AND HOSES:

4.10.01 Nylon-reinforced Rubber Hose Requirements:

4.10.01.01 Special features required:

a. Backup rings for flanged connections.

b. Type and material of hose suitable for application.

4.10.01.02 Installation requirements:

a. Install hose with piping anchored and guided according to the manufacturer's recommendations.

4.10.02 Rubber Lining:

4.10.02.01 Rubber line all hydrocyclone inlet feed headers, all piping, overflow and underflow collection launderers.


5.01.01 GENERAL:

5.01.02 The agitators shall consist of, but not be limited to, the following equipment:

5.01.02.01 Agitator housing, impeller and impeller shaft.

5.01.02.02 Motor.

5.01.02.03 Couplings, gear reducers and all required guards.

5.01.02.04 Mounting base and supports.

5.01.02.05 Mechanical seals for side entering agitators.

5.01.02.06 Special tools required.

5.01.02.07 Other equipment and tools as required to provide a complete agitator.

5.01.03 Design all components of the mixers for continuous operation at the conditions specified.

5.01.04 Flow patterns from the impeller and tank baffling shall be capable of maintaining solids in suspension with and without recirculating flow from the tank. The flow pattern shall be capable of re-suspending solids after a shutdown. "High-efficiency" axial flow impellers shall be provided.


VOL-II-I-SEC-I - 51

DCPL-11Z02

5.01.05 Contractor shall confirm the number and placement of the components making up each agitator system for each agitated vessel. The confirmation process may be accomplished by means of physical or mathematical modeling. Contractor shall notify Owner two weeks before testing/modeling is performed.

5.01.06 Motors and couplings shall be adequately protected from the slurry. Motors shall be mounted perpendicularly to the mixer shafts for top entering agitators. Provide outboard motor supports when recommended by the agitator manufacturer.

5.01.07 For top entering agitators, the agitator shaft and all components that could be splashed by the mixed fluid, shall be rubber coated (except where rubber coating is not possible). The coating shall be selected for abrasion and chemical resistance. The rubber coating on the mixer shaft shall be a minimum of 6 mm thick. The impeller shall be rubber-lined a minimum of 6 mm thickness with a minimum of 12 mm thickness on the impeller leading edges and other high wear areas. Final material selection is subject to the Owner’s approval. All coated parts shall be tested by a searching electrode with a minimum potential of 10,000 volts. Any defects found shall be properly repaired. Notify Owner at least two weeks in advance of the spark test so that he may be present to witness.

5.01.08 Wetted components for side-entering agitators shall be constructed of stainless steel selected for the service conditions. Alloy 255 (UNS 32550) is the minimum material that shall be considered. Final material selection is subject to the Owner’s approval.

5.01.09 Impellers and shaft shall be easily removable without disturbing the speed reducers or the motor. The shaft shall be able to be disconnected from the mixer housing with a coupling located as near as practical to the housing.

5.01.10 Side-entering agitators shall include a shut-off feature to allow maintenance on the agitators including replacement of mechanical seals without draining of the tank.

5.01.11 The agitator shaft shall be provided in a minimum of two sections of approximately equal length for top entering mixers if the shaft length is greater than 6 meters.

5.01.12 Provide reducing drive gears designed in accordance with American Gear Manufacturers Association (AGMA). All drives should be rated in accordance with the most conservative AGMA standards, and should be designed for service with mechanical mixers. The service factor shall be a minimum of 1.5. Design of the gear box shall incorporate the following features:

5.01.12.01 Internal shafting and bearings shall minimize the internal shaft deflections produced by torque, bending moments and shock.

5.01.12.02 Lubrication of gear drive shall be splash type. Oil pumps will not be allowed. No lubrication shall be allowed to leak into the tank. The drive on top-entering mixers shall be equipped with a dry-well seal so that retention of lubricating oil in the drive does not depend on oil seals.

5.01.12.03 Provide a sight glass or dip stick to check level in oil reservoir.


VOL-II-I-SEC-I - 52

DCPL-11Z02

5.01.13 Mechanical Seals (Side Entering Mixers):

5.01.13.01 Type of seals recommended by the mixer manufacturer for the application subject to Owner’s approval.

5.01.13.02 Seal faces shall be silicon carbide.

5.01.14 Bearings shall have a minimum AFBMA L-10 rating life of 80,000 hours.

6.00.00 DUCTWORK

6.01.01 Provide all ductwork connecting the gas path and other interfaces, through the precipitators, and to the adjoining Subcontract’s interface points. This includes transitions, expansion joints, structural slide bearings, turning vanes, lagging, insulation, and support steel.

6.01.02 Design ductwork and support steel such that no loads will be applied to ductwork provided by others at interface points unless effectively coordinated. Expansion joints, bolts, nuts, backing bars, and gasketing at interfaces to connections shall be by this Contract.

6.01.03 Provide expansion joints at interface points of ductwork within this Contract to ensure that no stresses in ductwork and supports are transmitted to other equipment.

6.01.04 Design ductwork and expansion joints for wind loading, snow loading, and seismic zone specified in this Contract.

6.01.05 Provide instrument connections as specified and required.

6.01.06 Ductwork shall be designed in accordance with NFPA 85 – Boiler and Combustion Systems Hazards Code and Clause 10.00.00 of the Boiler and Auxiliaries Specification Volume and the following:

6.01.06.01 Install 100 mm test ports upstream and downstream, as required by local and regional authorities, of each precipitator and as approved by Owner.

a. Locate all test ports in top of ductwork if gas flow is horizontal.

b. Test ports shall be Schedule 40 pipe with flanges and EDPM or fluoroelastomer gaskets.

c. Install test port pipes and flanges as indicated.

6.01.06.02 Provide a Unistrut monorail and trolley located directly above and in line with each row of test ports and capable of supporting a 136 kg concentrated load at any point along the monorail. Monorail height shall be at least 3 meters higher than the sum of the duct depth and the test port length. Provide access ladder to a platform 1.5 meters below and at one side of monorail. Provide an eyebolt attached to trolley for connection of Owner's tackle for lifting test apparatus.

6.01.06.03 Provide all connections for temperature and pressure measurements as specified.

6.01.06.04 Provide internal ladder rungs for access to all sections of ductwork.


VOL-II-I-SEC-I - 53

DCPL-11Z02


7.01.00 GENERAL

7.01.01 Provide a gas-gas heat exchanger to utilize hot flue gas to reheat the flue gas discharge from the FGD system.

7.01.02 The gas-gas heat exchanger shall have a design life of 30 years.

7.02.00 REFERENCES:

7.02.01 Applicable Codes and Standards:

7.02.01.01 Design, construct, test, and erect equipment in accordance with applicable codes and standards including, but not limited to, the following:

7.02.01.02 American Institute of Steel Construction (AISC):

a. Steel Construction Manual.


a. Boiler and Pressure Vessel Code.

7.02.01.04 National Fire Protection Association (NFPA):

a. 85 – Boiler and Combustion Systems Hazards Code.

7.02.01.05 Directorate for Standards, Metrology, and Quality (STAMEQ/TCVN)

a. 7740-2007 – Boiler – Technical requirement of design, construction, manufacture, installation, operation, maintenance

7.03.00 SUBMITTALS:

7.03.01 Submittals required shall include the following:

7.03.01.01 Arrangement and outline information.

7.03.01.02 Performance information.

7.03.01.03 Materials of construction

7.03.01.04 Painting specifications.


7.04.01 Experience:

7.04.01.01 All equipment and appurtenances furnished by Contractor shall have an acceptable history of satisfactory reliable service in central station use for a period of at least three years at comparable temperature, pressure, materials of construction, corrosion, and design stress levels.

7.04.01.02 Shops utilized by Contractor to fabricate pressure parts shall have provided similar fabricated parts that have an acceptable history of satisfactory reliable service in central station use for a period of at least three years.

7.04.01.03 Newly developed equipment with less than three years of actual service may be considered from established manufacturers, only if it has been adequately tested, meets the requirements of this Contract, and is approved by Owner.


VOL-II-I-SEC-I - 54

DCPL-11Z02


7.04.02.01 Perform all manufacturers’ standard factory tests on Equipment and Material.


7.04.02.03 Notify Owner when factory tests are to be made, so that they may have a representative witness the tests, if desired.



7.05.01 The gas-gas heat exchanger shall utilize heat from the flue gas at the inlet to the FGD system to reheat the flue gas leaving the FGD system.

7.05.02 The gas-gas heat exchanger shall be designed to reheat the flue gas to 90ºC prior to discharging to the stack.

7.05.03 The gas-gas heat exchanger shell design shall be in accordance with the duct design requirements stated in Volume II-B, Section I, Clause 10.

7.05.04 The gas-gas heat exchanger shall be one of the following types.

7.05.04.01 Regenerative (such as a Ljungström type air heater). The regenerative heater design shall be generally in accordance with the requirements stated in Volume II-B, Section I, Clause 8.

7.05.04.02 Tubular.

7.05.04.03 Cross flow plate type.

7.05.05 The required SOx emission rate shall not be exceeded with a gas-gas heat exchanger leakage in accordance with the following. This is to allow the plant to continue to operate until the next scheduled outage when leaks occur.

7.05.05.01 For the regenerative gas-gas heat exchanger the guaranteed SOx emission rate shall not be exceeded when the gas-gas heat exchanger leakage (on an inlet flow basis) is equal to the larger of (1) 10%, or (2) 5% greater than the initial guaranteed leakage rate.

7.05.05.02 For the tubular and plate type gas-gas heat exchanger the guaranteed SOx emission rate (on an inlet flow basis) shall not be exceeded when the gas-gas heat exchanger leakage is equal to 5%.

7.06.00 MATERIALS

7.06.01 All materials subject to corrosion shall be in accordance with the following:

7.06.01.01 The materials shall be suitable for operating in the acid corrosion environment for a period of 30 years with nominal maintenance required. This requirement can be met with either of the following.

a. Corrosion resistant materials, such as 316 SS, 317 SS, graphite, Alloy C-276 (UNS N10276), etc.

b. Low alloy materials protected with a suitable coating.


VOL-II-I-SEC-I - 55

DCPL-11Z02

7.06.01.02 The materials proposed shall be clearly stated in the proposal. The proposal shall also include material upgrade options and the price to incorporate the upgrade materials. A paper explaining why the selected materials are suitable for the service, including expected corrosion rate, expected rate of repair, and anticipated life shall be provided.

7.06.02 Final material selection shall be acceptable to the Owner.

7.07.00 CLEANING

7.07.01 A means of maintaining the cleanliness of the gas-gas heat exchangers shall be provided. This is anticipated to be either soot blowing or water washing, or a combination of the two.

7.07.01.01 Soot blower design shall be in general accordance with the requirements stated in Volume II-B, Section I, Clause 9.

7.07.01.02 Water washing design shall be in general accordance with the requirements stated in Volume II-B, Section I, Clause 8.

Documents

FLUE GAS DESULPHURISATION (FGD) SYSTEM - Chettinad Power Limited