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.

5

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

24

• 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

25

Emissions can be made cleaner than natural gas

emissions from domestic household gas stoves.