BIOwaste Blog: Plasma Gasification and Incineration Compared

http://biowaste.blogspot.hk/2007/01/plasma-gasification-and-incineration.html

Plasma Gasification and Incineration Compared

One of the common objections to the use of gasification to effect waste-to-energy conversions is the irrational claim that “gasification is just another name for incineration.” This is an old, false distortion of fact relating to controversy surrounding the use of waste-to-energy incinerators and the “Keep America Beautiful” program of the 1980’s. As related by Ratical.Org:

In 1980 DOE projected that by 1987 there would be 160,000 tons-per-day of incineration capacity in the U.S. and double this by 1992. But in reality in 1988 incineration capacity was only 50,000 tons per day, and it was expanding at a snail’s pace. In 1985 there were 42 new incinerators ordered, but by 1987 it was down to 25 and by 1989 new orders has dropped to 10. In 1987, for the first time in recent memory, more capacity was canceled (35,656 tons per day) than was ordered (20,585 tons per day). The incineration industry had hit a wall.

That wall was made up of local grass-roots citizens concerned about many aspects of solid waste incineration: dollar cost, hazardous air pollution, toxic ash, destruction of material resources, waste of energy, the political corruption that accompanies multi-billion-dollar public works projects, and the gobbling up of small, local waste haulers by the incineration giants.

Gasification is NOT incineration as the side-by-side comparison of plasma gasification and incineration below demonstrates (as published on the website of the Plasco Energy Group). While this company is focused on the production of syngas, other companies (BRI Energy, Fuel Frontiers, and others) are focused on the fermentation of cooled syngas into biofuels (like ethanol).

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In plasma gasification the waste input is pyrolysed by the high temperature into its constituent elements: H2, O2, C, N2 etc. The converter conditions are controlled so that prior to exit, the elements reform into the desired syngas that is rich in CO and H2. The materials that cannot be converted into syngas, such as metal, glass, rock and concrete are vitrified to produce an inert slag. The slag is 1/250th of the volume of the processed solid waste.

In incineration, excess O2 is added to the input waste so that at low temperature it burns. The result is heat and an exhaust of CO2, H2O and other products of combustion or partial combustion. As much as 30% of the processed solid waste remains as ash. This ash is a solid waste and could be categorized as hazardous solid waste