incineration (energy recovery through ii.pdf · air plasma gasification is not combustion ... air...
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Incineration (energy recovery through complete oxidation)
Mass Burn
Refuse Derived Fuel
Pyrolysis
Gasification
• Technology proven in 1989 at General Motors, Defiance Ohio
• Waste to Energy in 2001 at Hitachi Metals Eco-Valley, Utashinai, Japan
• WPC gasifier vessel 15 feet in diameter and over 50 feet tall
• Up to six (6) WPC plasma torches per gasifier
• Multiple feedstock capability
• Re-usable inert vitreous slag by-product (road construction, insulation)
• Syngas clean up using off the shelf proven commercial equipment
WPC Plasma Gasification
Reactor Cross Section
Partial oxidation process using air, pure oxygen, oxygen enriched air, hydrogen, or steam
Produces electricity, fules (methane, hydrogen, ethanol, synthetic diesel), and chemical products
Temperature > 750 oC
More flexible than incineration, more technologically complex than incineration or pyrolysis.
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Product yields (dry feed basis) for pyrolysis of wood.
A.V.Bridgwater
Mode Conditions Liquid Char Gas
Fast pyrolysisModerate temperature,
short residence time 75% 12% 13%
Slow PyrolysisLow temperature, very
long residence time30% 35% 35%
GasificationHigh temperature, long
residence time. 5% 10% 85%
The Syngas is mainly H2 and CO
Variety of Feedstocks Flexible Process Variety of Energy Products
Feed Handling
Air/Oxygen
Steam
Gas Clean-up
Slag
Aggregate
Syngas
Steam
Electric Power
GasifierBoiler
Gas Turbine
Optional Syngas Uses
Application: Power Generation
MSW
Coal
Biomass
Thermoselect
(http://www.thermoselect.com/index.cfm)
What is Gasification?
• Process that converts carbon-containing materials (MSW, biomass, coal, etc.) into a synthesis gas
• Syngas = carbon monoxide and hydrogen
• Syngas is a “cleaner” fuel than the original solid feedstock, resulting in cleaner emissions (reduced NOx, SO2)
What is Plasma?
• Man-made Plasma is created by passing electricity through a gas (air) causing a change in the state of the gas and a significant temperature increase often exceeding 10,000oF.
• Atoms of ionized gas have lost one or more electrons and have become positive charged
• Sun and lightning are natural plasma
• Superheated gas where positive and negative charges are separated (ionized)
Heating Technique using electrical arc Used for combustion, pyrolysis,
gasification, metals processing Originally developed by SKF Steel in
Sweden for reducing gas foriron manufacturing
Temperatures (> 1400oC) sufficient to slag ash
Plasma power consumption 200-400 kWh/ton
Plasma
Torch
System
Plasma
(5,540o)
Electricity
Air
Plasma Gasification is not combustion
Plasma Gasification converts solid fuel or
organic waste into a clean gaseous fuel
Refuse receipt/storage
Refuse feeding
Grate system
Air supply
Furnace
Boiler
WasteFlue Gas
Energy Loss (Radiation)
Mass Loss (unburned
C in Ash)
Particulates
Acid Gases
NOx
CO
Organic Hazardous Air Pollutants
Metal Hazardous Air Pollutants
Solid Condensable
Causes Too low of a comb T (incomplete comb) Insufficient oxygen or overabundant EA (too high T) Insufficient mixing or residence time Too much turbulence, entrainment of particulates
Control Cyclones - not effective for removal of small particulates Electrostatic precipitator Fabric Filters (baghouses)
From Cl, S, N, Fl in refuse (in plastics, textiles, rubber, yd waste, paper)
Uncontrolled incineration - 18-20% HCl with pH 2
Control
Acid gas scrubber (SO2, HCl, HFl) usually ahead of ESP or baghouse Wet scrubber
Spray dryer
Dry scrubber injectors
Source removal to avoid fuel NOx production
T < 815 C to avoid thermal NOx
selective catalytic reaction via injection of
ammonia
Remove certain waste components
Good Combustion Practices
Emission Control Devices
Electrostatic Precipitator
Baghouses
Acid Gas Scrubbers
Wet scrubber
Dry scrubber
Chemicals added in slurry to neutralize acids
Activated Carbon
Selective Non-catalytic Reduction
Bottom Ash – recovered from combustion chamber
Heat Recovery Ash – collected in the heat recovery system (boiler, economizer, superheater)
Fly Ash – Particulate matter removed prior to sorbents
Air Pollution Control Residues – usually combined with fly ash
Combined Ash – most US facilities combine all ashes
Construction fill
Road construction
Landfill daily cover
Cement block production
Treatment of acid mine drainage
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• Plasma Arc Gasification
• Conventional Gasification
- Fixed/Fluidized Bed Technologies
• Pyrolysis & Gasification
- Thermoselect Technology
• Pyrolysis
- Mitsui R21 Technology
• Incineration
- Mass Burn Technology
Process (1)
816
685
685
571
544
Net Electricity to Grid
(kWh/ton MSW) (2)
-
20%
20%
40%
50%
Plasma Advantage
Reference: EFW Technology Overview, The Regional Municipality
of Halton, Submitted by Genivar, URS, Ramboll, Jacques
Whitford & Deloitte, Ontario, Canada, May 30, 2007
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Emissions can be made cleaner than natural gas
emissions from domestic household gas stoves.