Boilers for Plant Waste-Rajavel
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Transcript of Boilers for Plant Waste-Rajavel
1
Steam generators using
Industrial waste as Fuel
J. Rajavel
Thermax Ltd
Outline
Type of Industrial Waste
Characteristics of Waste
Thermax Incineration route
Challenges in the Boiler design
Overall benefits to customer
Type of Industrial waste
Distillery Plant waste
Coffee Plant waste
Steel Plant waste
Paper Plant waste
Viscose Plant waste
Refinery Plant waste
Oil Mill / Oil extraction
plant waste
Saw mill plant waste
Tyre plant waste
Poultry waste
Other coal / coke
washery plant waste
Distillery Plant waste as fuel
Spent Wash - Spent wash fired boiler
Biogas – Bio-gas fired boiler
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Raw Spentwash-The Back end What is Spentwash?
All spirits go through at least two procedures -
fermentation and distillation. Fermentation is where
all alcohol is created, distillation is where the alcohol
is separated and removed. In order for fermentation
to occur, two things are needed
YEAST + SUGAR(molasses) = ALCOHOL + CO2
Spent wash is a brown liquid-waste that is generated
as a by-product during the distillation of fermented
molasses
A typical distillery generates 8 to 15 litres of spent
wash per litre of alcohol
Spentwash Characteristics Vs Issues
Varying solids content in raw spent wash.Acidic in nature
•Highly viscous at solid concentration >60%Spentwash concentration required is 55-60%solids to ensure bed stability and energy economics.
•High alkali content in ash leading to fouling of
heat transfer surfaces
High amount of chlorides leading to high temperature corrosion of super heater
Process Waste
High Moisture
High Alkali
High Chlorine
CHARACTERISTICS ISSUES
Mode of Disposal
3
Disposal Methods
Bio Methanation
Higher residual Liquid Discharge
70% energy conversion in Biogas
Composting
Huge area requirement
Land pollution due to leaching
Poor Commercial returns
Disposal problem during rainy season(open yard operation)
Incineration
100% SPW disposal
Steam to Process
Power Generation
Marketable Potash rich Ash
Why spent wash boiler
Zero Liquid Discharge norm has been implemented
Existing methods unable to meet ZLD
Bio-methanation
Bio-composting
Ministry of Environment and Forests
EIA study and pollution control methods
Spent Wash Characteristics
HighMoisture
HighDust
ProcessWaste
HighAlkali
HighChlorine
Design Considerations
Zero effluent discharge
Bed agglomeration
Spentwash spray system
Residence time
Online scale removal
NOx, CO reduction
Deep fluidised bed combustion
Proper proportioning of coal for
reducing the base-to-acid ratio
Location, cone-angle, droplet size
Two-pass furnace
Mechanical rapping
Suitable sizing and positioning of
secondary air, tertiary air ports
Challenges Solutions
4
Concentrated Spentwash Analysis
Ash Analysis
(%)Silica as SiO2 20.91
Iron oxide as Fe2O3 1.81
Calcium oxide as CaO 8.24
Magnesium oxide as MgO 6.95
Sulphate as SO3 8.41
Phosphate as P205 1.64
Potassium oxide as K2O 43.19
Sodium oxide as Na2O 2.76
Aluminium oxide as Al2O3 0.08
Titanium oxide as Tio2 0.01
Chlorides 6%
Ultimate Analysis (%)
Carbon 22.93
Hydrogen 2.21
Oxygen 15.22
Nitrogen 1.91
Sulphur 0.60
Moisture 40.00
Mineral matter 17.11
GCV 1,860 (kcal/kg)
Basic concepts...
Spent wash concentration - 60% solids
Spent wash to coal ratio - 20% by weight
Why coal as support fuel
General Arrangement Pressure part arrangement
To bag filter
5
Spentwash Boiler at Bannari Amman
Sugars-Mysore
ASH REMOVAL BY RAPPING
MECHANISM
Concentrator
Spray cap
Roof Jumpers
I pass rear wall header
Spentwash firing Arrangement
Cooling air Conn. From SA header
Spent wash gun
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CFD based Spray/Emission optimizationSpentwash Spray System Design of spentwash spray system for its spray gun location in furnace, spray cone shape and droplet size through pilot testing/CFD
Emission ControlOFA system optimization and furnace temp. prediction through CFD/KED modeling
Benefits to Customer
Customer meeting ZLD norms
Generation of captive power and steam to run Distillery
Continuos distillery operation with continuos consumption of
Spentwash
Alkali rich Flyash being shall be disposed to fertilizer
companies/Farmers
Every kilogram of concentrated spent wash replaces nearly 0.33
kg of Indian coal,CDM benefits to Customer
Byproduct from ETP, lowers fuel costs as it
replaces more expensive fuels
What is Biogas Distillery Plant waste- Biogas
Biogas composition
Methane CH4 - 50-55%
H2 S - 2.7%
CO2 - 35 -40 %
Moisture - 2- 10%
Heating Value – 4000 – 5100 Kca/Nm3
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Bio-Gas Characteristics Vs Issues
Varying Heating value of biogas.Acidic in nature
•Sustaining the Flame / Flame stability Oil support required and energy economics.
•Leads to corrosion in the pipes
•High acid dew point temperature
Lower Heating Value leads to suppression Flame
Process Waste
High Moisture
Sulfur
Lower GCV
CHARACTERISTICS ISSUES
Supply pressure from holder low and unsteady. Makes
burner operation unsteady.
During burner OFF cycle, biogas either is vented to
atmosphere or taken to a storage tank. This tank is an extra
capital investment.
Lean (low CV) gas means low radiant heat. Boiler/heater
need larger convection banks than normal. Oil-fired boiler or
heater may not give rated output on biogas firing
Design consideration- Biogas
When biogas & oil are burnt together, oil supplementing balance heat, flame interference causes unstable & incomplete combustion. Burner must be designed suitably
H2S & moisture in biogas corrode gas train & burner components. To prevent corrosion, stainless steel & plastics are required
Dew-point corrosion affects boiler/heater pressure part, duct & chimney
High moisture content in fuel means more heat loss through stack & lower output
Design consideration- Biogas
Thermax has supplied exclusive Biogas fired boilers . Combustion through dedicated burners
Thermax installations are there in biogas combustion in AFBC boiler in combinations with Coal firing in both In – bed nozzle design and Burner design
Thermax has supplied Traveling grate / Dumping grate
Bagasse fired boiler with Biogas burners.
Distillery Plant waste- Biogas
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Steel Plant waste as fuel
Char - Char fired AFBC / CFBC boilers
Blast furnace gas –
Coke oven Gas-
Corex Gas
Char / Dolochar - as fuel
What is Char-
Sponge iron Kiln byproduct
Steel Plant waste- Char
CHAR Ultimate Analysis
Carbon – 16.0 to 26.0% Volatile matter – 2 to 7%
Hydrogen- 0.20 to 0.75% Iron content in ash – 0.5 to 4%
Nitrogen- 0.25 to 0.75%
Oxygen 2.0 to 4.5%
Ash - 60.0 to 70 %
Moisture – 3.0 to 9.0%
Sulfur dioxide -0.20 to 0.30%
Heating Value – 1100 to 2300 Kcal /Kg
Char Characteristics Vs Issues
Varying Calorific value of Char.
•De-fluidization of bed
• Accelerate the erosion in furnace zone
•Difficult to combust
Bed / Bottom ash disposal
Process Waste
Iron content
Lower Volatile
High Ash
CHARACTERISTICS ISSUES
9
Design Considerations- Char
Disposal of Char
Bed agglomeration
Combustion system
Sustaining the combustion / Bed
temperature
Erosion in pressure parts
Frequent bed drain
Ash disposal system
Deep fluidised bed combustion
Proper sizing of char and monitoring the iron
content in the char
Hopper bottom AFBC / CFBC technology
Blending with high volatile solid fuel
Studded arrangement / refractory
Open hopper bottom design
Water cooled bed ash coolers / Pneumatic bed
ash coolers
Challenges Solutions
Open hopper bottom
AFBC
Open hopper bottom
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SALIENT FEATURES OF
HOPPER BOTTOM DESIGN1. REGULATED / CONTROLLED DRAIN.
2. BED DRAINING CAPABILITY FROM THE ENTIRE
BED AREA.
3. HEAVIER PARTICLES LIKE IRON CAN BE REMOVED
FROM THE RUNNING BOILER
4. BED DEFLUIDISATION AVOIDED.
5. BED PACKING IS AVOIDED DUE TO DRAINING
FROM ALL THE AREAS OF BED.
SALIENT FEATURES OF
HOPPER BOTTOM DESIGN6. LOWER BED DRAIN RATES. LESS BED MATERIAL
MAKEUP.
7. HIGHER SIZE CLINKERS ALSO CAN BE REMOVED-
4”-5” FROM THE RUNNING UNIT.
8. ENLARGEMENT OF CLINKERS CONTROLLED.
9. STARTUP CLINKERS CAN BE REMOVED.
SALIENT FEATURES OF
HOPPER BOTTOM DESIGN10.HIGH MOISTURE FUELS ARE ACCEPTABLE.
11. VARIETY OF FUELS CAN BE FIRED
12. ENTIRE BOTTOM IS OPEN, FOR MAINTENANCE IT
IS MADE SIMPLE.
Steam generator- Char as fuel
Thermax supplied more than 25 steam generators
with Hopper bottom AFBC boilers for the
incineration of Char.
Thermax Char fired CFBC boiler is under
construction.
11
Blast Furnace Gas (BFG)
• TBW and B & W have rich experience of supplying
Boilers for the Steel industry.
• These Boilers are designed to handle typical Steel
industry lean Gases like Blast furnace Gas,Coke
oven Gas, Corex Gas, LD Gas.
• Capacity range: 10 TPH - 500 TPH.
• Pressure range: 10- 100 kg/cm2.
• Temperature range: upto 560 Deg C.
Steel Plant Waste –BFG / Coke oven Corex gas
Characteristics of Blast Furnace Gas
VERY LOW COMBUSTIBLES & CALORIFIC VALUE
SLOW BURNING
UNDETECTABLE FLAME
LOW FLAME TEMPERATURE AND EMISSIVITY
WIDE VARIATIONS DUE TO PROCESS CHANGES IN:
- Pressure
- flow
- Calorific value
LOW SUPPLY PRESSURE
HEALTH HAZARD DUE TO TOXICITY.
DUST AND MOISTURE LOADING FROM
GAS CLEANING PLANT
Salient Features of TBW Boilers
TIME
-VERY LOW VOLUMETRIC HEAT RELEASE RATE:
(LOWER THAN 25000 BTU/HR ft3)
- Ensures complete combustion
-Provides higher residence time in furnace
-Enhances life of the boiler pressure parts.
TEMPERATURE
FURNACE REFRACTORY LINING:
-Ensures temperature necessary for stable combustion of
BFG.
TURBULENCE SCROLL BURNER
- Provides high mixing energy of air & BFG mixing for
efficient combustion
- Provides “spin” to ensure adequate mixing energy.
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Salient Features of TBW Boilers
B&W DESIGN BURNER:
- Own manufactured burners ensuring perfect matching and
integration with furnace geometry.
RICH EXPERIENCE:
- More than 50 similar boilers in operation world wide by B&W.
- 22 operating installation in India by TBW on BFG & other
Lean Gases.
Higher excess air for combustion of BFG.
Zero support fuel within 70-100% MCR with uninterrupted
supply of BFG at constant pressure/ calorific value.
Oil firing back-up if required by Customer.
Highest reliability.
JSW 200 TPH BFG Fired Boiler
TISCO 100 TPH BFG Fired Boiler Photos JSW 80 TPH BFG Fired Boiler Photos
13
Burners for 100 TPH BFG fired Boiler at TISCO, Jamshedpur
Burners for 80 TPH BFG fired Boiler at JVSL, Bellary
Paper Plant waste- ETP
Ultimate Analysis
Carbon – 12 to 14%
Hydrogen- 1.20 to 2.00%
Nitrogen- 0.25 to 0.35% Chlorine in fuel - 0.3 – 0.6%
Oxygen 10.0 to 13.5%
Ash - 20.0 to 30 %
Moisture – 45.0 to 55.0%
Sulfur dioxide -0.01 to 0.03%
Heating Value – 750 to 1200 Kcal /Kg
ETP Characteristics Vs Issues
Varying Heating value wrt moistre.
• Quenching the bed combustion / Flame stability
•Fuel feeding / stickiness in the feeder
•Corrosion of super heater tubes
Flame stability
Process Waste
High Moisture
High Chlorine
Very low GCV
CHARACTERISTICS ISSUES
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Design Considerations - ETP
Combustion of ETP
Flame Stability
Agglomeration property of ETP
Fuel feeding due to high moisture
Soot deposition
Chlorine corrosion in SH tubes
Hopper bottom AFBC technology
Blending of good fuels to maintain the bed
temperature
Hopper bottom AFBC gives flexibility to drain
the clinkers
Shaft less screw and live bottom bin with
stainless screw
Soot blowers
Inconel alloy material construction tubes
Challenges Solutions
CLIENT: - M/S SABAH FOREST INDUSTRIES SDN. BHD. , MALAYSIA
CLIENT: - M/S SABAH FOREST INDUSTRIES SDN. BHD. , MALAYSIA
Viscose Plant Waste - ETPS
Effluent sludge from Viscose plants
Fuel Analysis and its charatecristics
15
Viscose Plant waste- ETP
Ultimate Analysis
Carbon – 4 to 6 %
Hydrogen - 0.5 to 0.7%
Nitrogen- 0.25 to 0.35%
Oxygen 2.00 to 3.5%
Ash - 13.0 to 15.0 %
Moisture – 55.0 to 75.0%
Sulfur dioxide -0.5 to 0.7%
Heating Value – 350 to 450 Kcal /Kg
ETP Characteristics Vs Issues
Varying Heating value wrt moistre.
• Quenching the bed combustion / Flame stability
•Fuel feeding / stickiness in the feeder
•Dew point temperature
Flame stability
Process Waste
High Moisture
High sulfur
Very low GCV
CHARACTERISTICS ISSUES
Design Considerations - ETP
Disposal of ETP
Combustion system
Fuel feeding and storage
system
Flame stability
Deep fluidised bed combustion
Hopper bottom AFBC / CFBC
technology
Slurry type conveying system
and Special type screw feeder
Continuous other fuel support
Challenges Solutions
16
Oil Mill / Solvent Extraction
Plant Waste -
De oiled bleach oil earth ( Palm oil plant waste)
De-oiled cake fired boiler
De –Oiled Bran fired boiler
Palm wastes – Empty fruit bunch , Palm shell, Palm
fiber fired boilers
Palm oil Plant waste- Spent earth
Ultimate Analysis
Carbon – 11.53 %
Hydrogen - 2.65 %
Nitrogen- 0.09 %
Oxygen 3.8%
Ash - 74.0 %
Moisture – 7.0%
Sulfur dioxide -0.65%
Heating Value – 1100 to 1500 Kcal /Kg Fuel size – 100% less than 0.08 mm
ETP Characteristics Vs Issues
Varying Heating value wrt oil content.
• Quenching the bed combustion / Flame stability
•Fuel feeding / stickiness in the Furnace
•Fouling of pressure parts
Flame stability
Process Waste
High Ash
Fineness
Very low GCV
CHARACTERISTICS ISSUES
Design Considerations - DOBE
Disposal of DOBE
Combustion system
Fine ash deposition
Flame stability
Deep fluidised bed
combustion
AFBC technology
Soot blower
Intermittent other fuel
support
Challenges Solutions
17
Oil Solvent Extraction Plant –
De-oiled bran Ultimate Analysis DOB
Carbon – 35.81 %
Hydrogen - 2.68 %
Nitrogen- 1.09 %
Oxygen 26.5%
Ash - 16.31 %
Moisture – 11.0%
Sulfur dioxide -0.01%
Heating Value – 2600 Kcal /Kg
Design Considerations - DOB
Combustion system
Ash fouling on heating
surfaces
Fuel feeding and flow ability
AFBC Technology both Flat
bed and Open hoper bottom
design
Soot blower
Special type fuel feeder with
over bed feed system
Challenges Solutions
18
Coffee Plant Waste
Effluent from Coffee plants (NESTLE)
Spent Coffee ground (SCG)
Roasted Chaff
Green coffee waste
Coffee waste water
Coffee plant waste – Fuel
characteristics
Coffee waste Characteristics Vs
Issues
Varying Heating value wrt Moisture content.
• Flame / Self sustaining combustion stability
•Fuel feeding / stickiness in the Furnace
• Fouling of pressure parts
Lower IDT / Bed agglomeration
Process Waste
High Moisture
Powdery Fineness
High Alkali content
CHARACTERISTICS ISSUES
Design Considerations - SCG
Disposal of SCG
Combustion system
Fine ash deposition
Agglomeration /
Clinkerisation
Fuel storage / Feeding
system
Fluidized bed incinerator
AFBC technology
Soot blower
Sub- stochiometric combn
Live bottom bin with table
feeder system
Challenges Solutions
19
Oil refinery Waste - Petcoke
What is Pet coke-
Pet coke is the byproduct of crude oil distillation in
Petroleum refinery plants.
High Sulfur & High Fixed carbon .
Refinery Plant waste- Pet coke
Ultimate Analysis
Carbon – 86.7 % Volatile matter – 5 to 7%
Hydrogen- 3.18% Fixed carbon – 80 -87%
Nitrogen- 0.25 to 0.75%
Oxygen 1.16%
Ash - 1.0 %
Moisture – .0.8%
Sulfur dioxide -6 to 8%
Heating Value – 7800 to 8500 Kcal /Kg
Char Characteristics Vs Issues
Varying Sulfur content .
• Sox production is higher.
•Difficult to combust
Combustion temperature band width
Process Waste
High sulfur
Lower Volatile
IDT
CHARACTERISTICS ISSUES
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Design Considerations- Char
Combustion System
Bed agglomeration
Load fluctuation
HIGH TEMPERATURE /
SULFUR CORROSION
AFBC / CFBC technology
Proper maintaining bed
temperature and blending with
low IDT coal
High volatile fuel support for
quick response.
Lime stone addition and Special
grade SS material construction
Challenges Solutions
110 TPH CFB Boiler at Sourashtra cements
21
Other Industrial waste –
Palm shell / palm kernel/ Palm empty fruit bunch fired boilers-
Pusher grate boilers supplied by Thermax
Saw Dust / Sander dust fired boilers – AFBC boilers have
been supplied by Thermax
Coir Industry waste – Coconut Frond, coir waste fired TG /
AFBC boilers have been supplied by Thermax.
Other Industrial waste -
Oil Mill / Oil extraction
plant waste
Saw mill plant waste
Tyre plant waste
Poultry waste
Other coal / coke
washery plant waste
Thanks for the
attention