Plasma Gasification - Inputs & Outputs
Updated: Apr 11, 2018
Virtually any material, including low-level radioactive waste under certain conditions, can be reduced using plasma gasification.
Materials that can be safely and effectively treated include coal, sludge, incinerator ash, hazardous fly ash, medical waste, pathological wastes, paper, cardboard, plastics, fiberglass insulation and other products, asbestos, wood, glass, ceramics, rubber, tires, asphalt shingles, used roadway asphalt, oil sands, sewage sludge, Portland cement manufacturing waste, composite materials containing resins, plastic piping, solvents, paints, and other carbon-containing materials including mixed solid waste. The system will also handle such materials as steel beams and rebar, copper piping, steel, aluminum, and copper wire, and even concrete, stone and bricks. Plasma gasification will also handle treated wood and even contaminated soils – both a problem currently for both landfill and incineration operations.
The principal product of plasma gasification is a low to medium calorific value synthesis gas composed of carbon monoxide and hydrogen. The clean syngas can be converted into a wide variety of energy products including:
1. Electricity, through gas turbines, reciprocating engines and in the future, fuel cells
2. Heat and steam, and Summary of Qualifications 5 Confidential Information
3. Liquid fuels including: a) Ethanol; b) Jet fuel; c) Diesel/Naptha; d) Methanol; e) Propanol
Solid wastes from plasma gasification include a vitrified, glass-like, inert slag and small volumes of other solids that come from cleaning of filters and disposal of chemicals collected in the gas scrubbing process. The volume of solid wastes is variously reported as in the range of 5-15% the volume of the incoming waste stream, with the volume of slag determined by the proportion of non-organics in the material being treated. In recently built plasma waste-to-energy plant, the slag is used as aggregate for concrete products. While the slag material is potentially marketable, development of profitable markets is not a given and cannot be taken for granted.
The production of products other than syngas and slag is dependent upon the nature of the waste stream. For instance, source separation ahead of the plasma arc could yield various recyclable materials. In addition, metals sent through the process can be collected in molten form for subsequent processing in smelters, provided that the volume of metal is large enough to warrant separation. Small volumes of non- economically recoverable metals wind up as part of the vitrified slag. Chlorine and sulfur can also be collected as by-products, in the form of hydrochloric and sulfuric acids, respectively.
A plasma gasification combined cycle power plant or reciprocating engine plant is completely different than an incineration plant from an emissions perspective. Where incineration technology literally burns waste to create energy, plasma technology uses extreme heat to break down the waste to its molecular constituents including hydrogen and carbon monoxide, the two building blocks of syngas. In a combined cycle or reciprocating engine application, syngas is cleaned up to a specification similar to natural gas. It is this clean syngas that is burned in a gas turbine or reciprocating engine to make power. Emissions from this sort of plant will be very similar to a natural gas fired power plant. The emissions from a plasma treatment plant will be substantially lower than traditional mass burn or other processes commonly used in the waste to energy industry. Diversion of waste from landfills (where the potent greenhouse gas methane is formed) will result in substantial net decreases in greenhouse gas emissions as CO2 equivalent. Since the proposed organic feed stocks are post consumer waste streams, the project represents a renewable and sustainable clean energy resource