Developments in Industrial Boilers, WHR and Power Boilers

CHEEMA BOILERS LIMITED

Welcomes ALL Delegates to

National Workshop on

Efficient O&M of Boilers

Venue: Visakhapatnam

Time: 7th & 8th December 2015

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Use of steam : Utility for Power Or Process

Assembly :Shop assembled/Site assembled

Nature of support : Bottom /Top supported

Steam condition: Saturated/Superheated

Firing system : Oil/ Gas fired

Solid fuel fired fixed grate, Dumping grate, Reciprocating grate, Traveling grate

Pulverized fuel fired, Fluidized bed, AFBC and CFBC

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BI–DRUM AFBC WATER TUBE BOILER

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BI-DRUM WATER TUBE TRAVELING GRATE BOILER

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DUMPING GRATE WATER TUBE BI-DRUM BOILER

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Fire tube boilers

Water tube boilers

Fire cum Water tube boilers

Heat source : Coal, Oil, Gas, Bio-Mass, Waste heat

Construction : Bi-drum, Single drum, Multi-drum, Shell & Tube

Installation : Out door / In door

Circulation : Natural / Forced/Once throw

Draft: natural/forced/induced/balanced

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Super Heater Coil

Membrane

Membrane

Bank Tubes

Boiler parameters

Capacity, Steam outlet pressure , Steam outlet temperature , Feed water inlet temperature

Fuel characteristics

Boiler efficiency

Ambient conditions

Other statutory and auxiliary stipulations

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Ambient temperature

Relative humidity

Site elevation

Seismic zone

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Boiler efficiency = Heat Output / Heat Input i.e.

Steam Enthalpy x Steam Output Fuel Input x Fuel Enthalpy

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Dry flue gas loss : Enthalpy difference between flue gas leaving boiler and ambient air multiplied by dry flue gas quantity

Fuel moisture loss : Heat taken by the fuel moisture to become water vapour

Moisture due to combustion of hydrogen loss : Every unit of hydrogen in fuel produces 9 units of moisture. Heat taken by this moisture to become water vapour

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Contd…..

Air moisture loss : enthalpy difference in moisture brought in by combustion air between flue gas temperature and ambient temperature

Unburnt carbon loss : heat lost due to incomplete combustion of carbon in fuel

Unaccounted losses : small losses which can not be accurately calculated like heat loss in blow down water , heat going with ash , heat loss by radiation from boiler openings etc.

Radiation loss : heat loss from boiler external surface to atmosphere

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Contd…..

Considerations

Initial cost vs. Running fuel cost

Energy conservation

Waste fuel utilization

Governing factors

Excess air

Flue gas outlet temp.

Moisture and hydrogen content in fuel

Ambient temperature and moisture

Completeness of combustion

Effectiveness of insulation

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Mechanical Dust Collector. - Can be single or multi-cyclone. - Dust collection efficiency between 90% to 95%. - Dust separates due to centrifugal action. - Good for large particle sizes. - Draft loss around 75-100 mmwc.

Wet Scrubbers : - Uses moisture to capture dust. - Used in boilers using low ash fuels like bagasse. - Water is an essential pre-requisite. - Draft loss 75 to 100 mmwc. - Converts air pollution to water pollution.

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Contd…..

Electro-static precipitators: Ionizes the gases and dust captured on the cathodes Efficiency as high as 99.9% Can capture finer dust Draft loss only 25 mmwc High voltage used as elements to be electrically charged Used for large solid fuel fired boilers and cement plants

Bag filters : Uses cloth as filters Generally used in low erosive dust Efficiency above 99.9% High draft loss 75 to 150 mmwc and hence high ID fan power

consumption Bags needs frequent maintenance and replacement

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Contd…..

C + O2 CO2 + Heat

2H2 + O2 2H2O + Heat

S +O2 SO2 + Heat

I kg of C requires 2.667 kg of Oxygen

1 kg of H2 requires 8 kgs of Oxygen

1 kg of Sulphur requires 1 kg of Oxygen

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Stoichiometric air is the quantity of air theoretically required to complete the combustion of fuel.

Practically stoichiometric air quantity is not sufficient to complete the combustion due to fuel particle size and homogeneity of fuel and air is not good.

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Excess air is the quantum of air that is required over and above stoichiometric air quantity to have satisfactory completion of combustion.

Solid fuels require more excess air than liquid fuels.

Liquid fuels require more excess air than gaseous fuels.

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Fixed grate / Reciprocating grate: 40-50 %

Dumping grate : 35-40 %

Traveling grate : 35%

Traveling grate with spreader stoker : 30-35 %

Fluidized bed : 20-25 %

Pulverized fuel firing : 20%

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Design Consideration And Optimizations for Biomass Fuel Fired Boilers

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Charateristics of Bio-mass fuels BIOMASS CONTAINS ALKALIES NORMALLY CONCENTRATION

OF POTASSIUM & SODIUM OXIDE LOWEST ASH FUSION TMP. TO 950C.

PRESENCE OF SILICA WITH ALKALIES CREATES

AGGLOMORATION & FOULING ON HEATING SURFACES SILICA IN FLY ASH CAUSE EROSION OF HEATING SURFACES CHLORIDE COMPOUNDS OF RDF CAUSE CORROSION OF

HEATING SURFACES. BIOMASS COMBUSTION PRODUCTS CONTAINS SO2/SO3 THAT

CAUSE ACID DEW POINT CORROSION.

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Ultimate Analyses of Coal & bio-mass fuels

Analysis Paddy husk G N shell Julia Flora Indian Coal Cotton Stalk Bagasse

Carbon (%) 36.67 49.36 36.45 37.10 44.90 23.50

Hydrogen 04.57 04.34 04.39 02.30 07.50 03.00

Nitrogen 01.25 00.48 02.12 00.70 01.20 01.18

Sulphur 00.18 00.32 00.28 00.30 00.00 00.18

Moisture 09.44 10.05 25.00 08.00 06.93 50.00

Ash 15.01 01.89 02.34 45.00 04.00 01.50

Oxygen 32.88 33.56 29.52 06.60 35.47 20.64

GCV(kcal/Kg) 3275 4190 3400 3500 4400 2272

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For Coal :

Manual stoking with fixed grate Gravity feeding with chain grate Spreader stoker with traveling grate Spreader stoker with fixed or dump grate Pulverized fuel firing (for coal/lignite) Fluidized bed combustion

For Palm Fibre/ Bagasse/ Other Cellulose

Reciprocating/ fixed grate with gravity feeding Spreader stoker with fixed / dumping grate

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Emissions are generally of two types : 1. Air emissions 2. Liquid emissions The various air emissions from a boiler are : 1. Particulates 2. Nitrogen oxides ( NO,NO2), generally referred as Nox 3. Sulphur gases ( SO2 , SO3) , generally referred as Sox 4. Carbon monoxide ( CO) Normal Particulate Emission Limits : 1. Upto 2 TPH Boilers : 1200 - 1500 mg/N.M3 2. 2 TPH TO 10 TPH : 300 - 600 mg/N.m3 3. Above 10 TPH : 50 - 150 mg/N.m3 The various liquid emissions from a boiler plant are : 1. Back-washed water from water treatment plants 2. Blow down water 3. Water from wet scrubbers

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TEST RESULTS OF POULTRY LITTERS

S. No.

Characteristics

Unit

VALUES

I. Proximity Analysis

1. Moisture content

2. Volatile matter

3. Ash content

4. Fixed carbon

5. Calorific value

(%)

(%)

(%)

(%)

(K Cal / Kg

16.96

53.03

21.82

8.19

2760

II. Ultimate Analysis

1. Carbon

2. Hydrogen

3. Nitrogen

4. Oxygen

5. Sulphur

6. Phosphorus

(%)

(%)

(%)

(%)

(%)

(%)

32.77

1.16

2.82

24.32

0.05

0.10

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TEST RESULTS OF POULTRY LITTERS

S. No.

Characteristics

Unit

VALUES

III. Ash Analysis

1.Silica as SiO2

2.Calcium as CaO

3.Magnesium as MgO

4.Iron as Fe2O3

5.Sodium as Na

6.Potassium As K

7.Sulphate as SO4

8.Phosphorus as P

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

5.10

8.03

0.60

0.01

0.42

0.60

0.01

1.02

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Ist POULTRY LITTER BASED POWER PLANT DETAILS

NETT ELECTRICAL OUTPUT - 10 MW

FUEL CUNSUMPTION - 14 T/Hr

STEAM CONDITION - 62 Bar / 500 C

HEAT VALUE - 50 % OF COAL

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S. No.

DESCRIPTION

POULTRY LITTER FIRED BOILER

1. Type of furnace

FBC

2. Furnace Volume

50 % EXTRA Volume to ensure low flue gas velocity

3. Furnace Temp.

About 150 °C Less to accommodate high potash

content.

4. Furnace Height

About 1.5 times extra Height in Furnace which provides

high furnace volume and longer residence time for fuel

5. Bed Area

Lesser grate area especially designed to accommodate

the above fuel

6. Heat release rate

Lower heat release is considered to keep the furnace

temp. under control

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7. Air Distribution Over fire air distribution uniform for better combustion of fuel.

8. Tube spacing Extra Tube pitch to take care of choking of tubes

9. Boiler Bank Single pass to prevent choking

10. Fuel bunker SS lining in slope area to ensure better flow of fuel

11. Ash collection Hoppers Extra slope to avoid bridging of ash

12. Soot Blowers Soot blowers are required at different locations to prevent sticking of ash on the tube surfaces.

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Electricity from Municipal Solid Waste

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(MSW) refers to the stream of garbage collected through community sanitation services. Medical wastes from hospitals and items that can be recycled are generally excluded

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MSW consists mainly of renewable resources such as food, paper, and wood products and nonrenewable materials derived from fossil fuels, such as tires and plastics

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Recyclable materials are separated out, and the remaining waste is fed into a combustion chamber to be burned. The heat released from burning the MSW is used to produce steam, which turns a steam turbine to generate electricity

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Burning MSW produces nitrogen oxides and sulfur dioxide as well as trace amounts of toxic pollutants, such as mercury compounds and dioxins. Although MSW power plants do emit carbon dioxide.

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MSW power plants reduce the need for landfill capacity because disposal of MSW ash requires less land area than does unprocessed MSW.

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MSW

URBAN

RURAL

INDUSTRIAL

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URBAN

RESIDENTIAL

COMMERCIAL

CONSTRUCTION ACTIVITY

BIOMEDICAL TREATMENT

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METHODS OF FIRING OF MSW

CAN BE FIRED AS FUEL

CAN BE PROCESSED AND FIRED AS RDF

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ENERGY CONTENT (DVLONG’S FORMULA)

145 C + 610 [ H2 - O2 / 8 ] + 40S + 10 N

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Municipal Solid Waste

Defined as anything that can be picked up from the road

Lot of segregating to be carried out

Heat value varies from 600Kcals/Kg to 1200Kcals/Kg

Segregating process has to be at garbage collection point

Establishing RDF (Refuse derived fuel) plants at economical operation

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The Hard Water can cause such Scaling in

boiler resulting in loss of efficiency and

life of boiler.

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Drum Operating Pressure

bar(g) Upto 20 21-40 41-60 Remarks

Hardness max- ppm 1.0 0.5 NIL Note 4

PH at 25°C 8.8 – 9.2 8.8 – 9.2 8.8 – 9.2 Note 1

Oxygen max –ppm 0.02 0.02 0.01

Total iron max- ppm 0.05 0.02 0.01

Total Copper max-ppm 0.01 0.01 0.01

SiO2 max-ppm 1.0 0.3 0.1 Note 4

Conductivity at 25°C (µs/cm) 10.0 5.0 2.0 Note 4

Hydrazine residual-ppm NIL NIL 0.02- 0.04

an energy recovery heat exchanger that recovers heat from a hot gas stream producing steam that can be used in a process (cogeneration) or used to drive a

steam turbine (combined cycle).

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WHRB FOR SPONGE IRON PLANT

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Revamps & Retrofits User friendly re-designing

Capacity enhancement

Fuel firing changes

Efficient accessories / fittings addition

Overall cycle efficiency improvements

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WE CONVERT THE SUGAR MILL INTO A POWER HOUSE

We all are aware that Sugar mill boilers and turbine work during the

sugar season and remain idle during off sugar season which is a long time of 6 – 8 months.

CBL has carried out an experiment at Dhampur Sugar Mills, Dhampur two years back. Where they have converted their 80 TPH 65 Kg/cm2 bagasse fired dumping grate boiler to a Fludised Bed furnace which can burn rice husk, mixture of rice husk and bagasse, saw dust and lower grade coal with as high as 82% efficiency.

The same boiler can be converted back to dumping grate and can work on 100% bagasse as fuel during sugar season and can be re-converted to Fluidised Bed during off season. The conversion time both ways takes 3 – 4 days.

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With this upgradation, the 20 MW power plant has worked during

entire year. Thereby, this break through hasl made a way for every

sugar mill to become a power house during off season.

The same organization has awarded CBL the contract for similar

conversions for their 2 mills, i.e., DSM Sugar Mills, Rozagaon and

Asmoli. Hence it is proved that the system is perfect and viable.

The above fact have been studied by “Word Alliance for Deceralised

Energy” in 2004 and have confirmed that upto 25% power demand of

India can be met by Sugar Mills with the above arrangement. Copy of

the report is available.

The schematic diagram for the above system is enclosed.

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SCHEMATIC DIAGRAM FOR CONVERTING A DUMPING GRATE BOILER TO FLUIDISED BED DURING OFF SUGAR SEASON AND VICE VERSA

THANKS FOR YOUR

CONCENTRATION

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