OVERVIEW OF SUPERCRITICAL THERMAL POWERPLANT , DPSTS

Welcome

OVER VIEW OF 2*800 MW SRI DAMODARAM SANJEEVAIAH THERMAL

POWER STATION

contents

Location Nellore, Andhra

Pradesh

Status Under Construction

Construction cost 8432/- crores

Owner(s) APPDCL

Operator(s) APGENCO

Primary fuel Coal-fired

Units operational 1*800 MW

Name plate capacity 1600 MW

Fuel

• Domestic washed coal & imported coal in 70:30 ratio with 27.5% Ash

• GCV(gross calorific value) of 4,800 kCal/kg shall be used as a fuel during normal operation

• LDO(light diesel oil) as well as HFO(heavy fuel oil) shall be used as a startup as well as support fuel

Fuel • Coal is mined from Kalinga ghat , Talcher Coalfield,

Angul district , Orissa

• shipped to krishnapatnam port by MGR trains and Coal barges and loaded to conveyer belt by stacker

stacker

Fuel

Pulverisation Fine powder of coal ,grinded by millers is fed

into furnace by hot air(primary air). Secondary air is fed into furnace to complete

combustion. Amount of primary air depends on load(>3%) High thermal efficiency Better control over load fluctuations Free from clinker and slagging troubles

MILLSA Mill is a mechanical device for the grinding coal upto

desired finenessThere are 6 mills , located adjacent to furnace at ‘0’ M

level

Furnace• Tangential firing-flame envelope rotates ensuring

through mixing within the furnace

• Heat energy is transferred through radiation (80%) and convection(20%).

Furnace

• Heat generating rates of 1.5x 106 kJ/m3/hr can be achieved

• Maximum amount of coal can be achieved with min . space and time

• Through tip(vertical arc) temperature can be varied upto 1000c

• So constant superheat temperature can be maintained

Ash handling plant

• Ash generated is about 30-40%of fuel consumption.

• Must be removed time to time • due to hotness , difficult to handle

Bottom ash removal system• Non combustible residue of combustion of furnace is

bottom ash• Bottom ash falls from furnace to ash sluice trench and discarded to ash pond after mixing with water

Electrostatic precipitator An ESP is a filtration device that removes fine

particles from a flowing gas using the force of an induce electrostatic charge minimally impeding the flow of gases through the unit.

Electrostatic precipitator• Dirt particles are negatively charged

• They are attracted to the positively charged plates and stick there

• From time to time, the collecting plates are shaken to empty away the soot (rapping mechanism)

ESP

• collected in ESP hoppers

• We have 8X8 hoppers

Fly ash removal system

Fly ash removal system• Pneumatically send to silo and then to trucks• Fly ash is used in 1.production of cement clinkers, concrete, ceilings 2.structural fills , agricultural purposes, floor etc

Water treatment plant

• Through ion exchange process , RO and filtration by resin beds water is demineralised

Water treatment plant

DEMINERALISED(DM) Waterparameter valueConductivity <0.2 μS / Cm at 25 Deg.C

pH value 9 - 10 at 25 Deg.c

Total silica <0.02 ppm as SiO2

Iron as Fe Not detectable as per ASTM methods

Free CO2 ppm (as CO2 )

“

Total Hardness “

Sea water

PARAMETERS AS VALUE

pH - 7.6

Turbidity NTU 10

P-alk / M- alk as CaCO3 ppm 98

Ca hardness as CaCO3 ppm 1100

Mg hardness as CaCO3 ppm 5050

Chloride as Cl % 1.89

Silica SiO2 ppm 3.8

Babcock and Wilcox boiler• Boiler is a device for generating steam for power,

processing and heating purposes• Supercritical boiler operates above critical point

Supercritical boiler• steam turbine efficiency improves significantly

compared to the typical subcritical cycle.

• The load change rate capability of the system is not restricted by the turbine

• Steam temperature at the inlet and outlet of the reheater is nearly constant over a wide load range

• The boiler feedwater pump power is significantly reduced at lower loads

• Short startup times

Classification Supercritical boiler

UP

Universal Pressure (UP®) boiler.• The original B&W boiler for supercritical applications was the

Universal Pressure (UP®) boiler. • These boilers, nine of which are in operation, are among the largest

capacity fossil fuel boilers in the world. SPECIFICATIONS• Capacity, steam output: 700,000 lb/h (90 kg/s)• Pressure: Subcritical, usually 1800 to 2400 psi throttle pressure with 5%

overpressure capability. • Superheater and reheater outlet temperatures: 538 to 566C • Fuel:Pulverized coal.

SWUP

Spiral Wound Universal Pressure Boiler

• Designed for both base load and variable pressure load cycling operation as well as on-off cycling operation.

• The unique feature of this boiler, compared to other boilers, is that the tubes in the furnace, from the lower furnace inlet headers to a location near the furnace arch, are wound around the furnace circumference rather than being vertical.

• This design allows the fluid in the tubes to pass through the various heat flux zones around the furnace providing a more uniform outlet enthalpy.

Spiral Wound Universal Pressure Boiler

SPECIFICATIONS• Capacity, steam output: From 2,000,000 lb/h (252 kg/s) to more than

10,000,000 lb/h (1260 kg/s).

• Operating pressure: 3500 psi (24.1 MPa) throttle pressure with 5%

overpressure; higher pressures available.

• Superheater steam temperatures: As required, currently in the 595C range.

• Fuel:Pulverized coal.

Vertical Tube Universal Pressure Boiler

• A once-through boiler, applied to systems with a capacity of 400 MW or larger

SPECIFICATIONS

• Capacity, steam output: 252 kg/s to more than 1260 kg/s. • Operating pressure: 3500 psi throttle pressure with 5% overpressure;

higher pressures available. • Superheater steam temperatures: currently in the 595C range. • Fuel:Pulverized coal.

BOILER

Main steam flow..........2600 T/hr SH steam press..............255 kg/cm2 (g) SH steam temp..............568° C Feedwater temp............307° C RH steam flow...............2052 T/hr RH steam press.............57.8 kg/cm2 (g) RH steam temp..............596° CHeight............................

BOILER

Fuel Design RangeGCV, kCal/kg 4800 4000-5000

Moisture, % 9.5 6.0-20.0

Ash, % 27.5 25.0-34.0

Volatile matter,% 28.5 20.0-33.0

Fixed carbon,% 34.5 24.0-40.0

HGI 50 5-55

Boiler accessories Economizer Waste heat of the flue gases is utilized for heating the

feed water Air Pre-heater Transfers heat from flue gases to primary/secondaryAir by means of rotating heating surface elements

Super heater Increases the temperature of the steam above its

saturation point

Boiler accessories P.A.Fan (two per unit-50% capacity each) designed for handling atmospheric air upto a

temperature of 500c

F.D.Fan (two per unit-50% capacity each) designed for handling secondary air for the boiler

I.D.Fan (two per unit-50% capacity each) 1. located between ESP and chimney. 2.used for sucking flue gas from furnace

Boiler accessories• SCR technology 1.Converts NOX into N 2 and water . 2.Anhydrous/aqueous NH3 or urea is added to

stream of ………flue gases and is adsorbed onto a catalyst

4NO + 4NH3 + O2 → 4N2 + 6H2O

3.They reduce NOx by 70-95%

SCR

• SCR incorporating Ammonia Injection Grid (AGI) and IsoSwirl Mixing system

economizer

Steam Turbine• Being a form of engine , requires in order to function a

suitable working fluid a source of high grade energy and sink of low grade energy

Low presure module of sft 100 alstom

Steam Turbine• Greater heat drop• Absence of internal lubrication(no filters)• Develops many times the power compared to

reciprocating engines

3 stage turbine(tandem compounded)

Steam Turbine• The cylinder(stator) contains fixed blades , vanes and

nozzles that direct steam into moving blades(rotor)

• The rotor are completely enclosed in a alloy steel outer case (one capable of withstanding high pressures and temperatures).

Steam Turbine• The rotor of large steam turbine consists of large ,

intermediate and low pressure sections.• change in direction of motion gives rise to a change of

momentum or force• this is driving force of the primemover

Four Cylinder Turbines

Turbine name plate details

Output 800,000kW Speed 3000rpm HP STEAM PRESS. 24.2MPa(a) HP STEAM TEMP 565 deg

Cooling tower(hyperbolic)

• Required when positive control of temperature is required

• Rate of evaporation of water depends on 1 amount of water surface area exposed 2 time of exposure and R .H of air 3 (inlet air WBT-water inlet temperature)

Cooling tower(hyperbolic)• It is necessary to precool the hot water from condenser

So (Two-Ts ) Is high • Vacuum at condenser can be maintained

• It comprises of 30% of budget

• Due to large base , withstands hurricanes

• No fanes are needed

• Chimney shape creates it own draught • No Ground fogging and warm air recirculation

Cooling tower(hyperbolic)• Height = Plan------circular• Diameter= Profile---hyperbolic

• (inside)

Cooling tower(hyperbolic)• Steel reinforced concrete structure

• Mostly hollow inside• Bottom is 10m above air-intake

• Force causing air to flow F=H(w0-wi)

Active power – 604.35MWReactive power – 46.35MVAR

Generator kV : R-Y – 24.32kV : Y-B – 24.32kV : B-R – 24.23kV Generator Amps : R-ph – 14.14kA : Y-ph – 14.33kA : B-ph – 14.61kA

Frequency : 49.97Hz P.F : 1.00

GENERATOR PARAMETERS

FIELD PARAMETERS

• Field voltage : 288.33V• Field current : 3452.6A• Rotor temperature : 65.13’c• POS 90R(AUTO) : 101.36%• POS 70E(MANUAL) : 147.89%

Fig. 19 Switchyard

Switchyard is a part of electrical generation, transmission and distribution

system.

Switchyard generally have circuit breakers, CT’s ,PT’s, Bus bars,

Transformers, Protection control equipments, Switches etc.,.

Fig. 20 Circuit Breaker

Circuit breaker: A circuit breaker is an automatically operated electrical

switch designed to protect an electrical current from damage caused by

overload or short circuit. The basic function of CB is to detect a fault

condition and, by interrupting continuity to immediately discontinue

electrical flow.

Fig. 21 Lightning arrester

Insulators: The insulators provide necessary insulation between line

conductors and supports and thus prevent any leakage current from

conductors to earth.

Lightning Arrester: It is a device used on electrical power systems and

telecommunication systems to protect insulation and conductors of the

system from the damaging effects of lightning.

Fig. 22 Voltage transformer

Voltage transformer: These are necessary for isolating the protection,

control and measurement equipment from the high voltages of the power

system. These are used to supply appropriate values of voltages to the

equipment.

Fig. 23 Current transformer

Current transformer: To feed the current circuits in protection systems

employing secondary relays current transformers are used.

Bus coupler: Two different bus sections of two different power

transformers are connected by means of a bus coupler.

Relay: It gives a tripping signal in case of any irregularity or faults.

Thank you by

HARSHA.S