PlascoEnergy Group (Plasco), an Ottawa, Ontario waste conversion and energy generation company, will provide the first waste gasification facility in North America, Matter Network reported recently. Gasification converts carbonaceous feedstocks, such as municipal waste, biomass or coal into a combustible gas. The gas can be used to generate electricity or steam or as raw material for chemical or fuel production.
Plasco’s gasification facility, to be built in Ontario, will convert trash to electricity. Plasco owns a number of patents directed to various components of its waste conversion system, and the complete facility is covered by International Application No. PCT/US2007/06840 (‘840 application) (there is a U.S. counterpart to this application, but it hasn’t been published yet).
The ‘840 application describes a more efficient gasification facility that reduces the cost of the generated energy by recovering its own waste heat and using it to drive the gasification process. The Plasco facility also performs the reactions at cooler temperatures to cut energy consumption.
A quick read of the ‘840 application’s claims suggests that a key novel aspect of the technology is the horizontal orientation of the gasifier. The gasifier includes lateral transfer units for moving the waste or feedstock material through the horizontal gasifier during processing. A control system allows individual control of the units and enables extraction of volatile by-products at each processing stage to optimize performance and efficiency.
The Plasco Conversion System comprises two major stages – waste conversion and power generation. In the first stage, waste is fed into the primary chamber of a converter and the material is gasified by recovered waste heat. In the second stage, the resulting gas product is used to run turbines and generate energy.
Waste is fed into the primary chamber of a converter where it is gasified using waste heat recovered from a downstream refining chamber. The gasified product, which typically contains carbon monoxide, hydrogen, tars and unreacted carbon, moves on to the refining chamber where it is refined by plasma torches.
Plasma is a partially ionized high temperature luminous gas, and the type of gas used can be varied to provide control over chemical reactions. The torch heat dissociates the gas molecules to allow their recombination into smaller molecules that are more useful for energy generation.
Solid residue from the primary chamber is melted and rapidly cooled in a water bath. According to Plasco’s web site, the resulting pellets are inert and non-hazardous, and may be used as construction aggregate for roads, concrete or other building materials.
After exiting the refining chamber, the gas then passes through the heat recovery unit, where waste heat is recovered.  Finally, the gas is cooled and cleaned of particulates, metals and acid components.Â
In the power generation stage, the synthetic gas, or syngas, is used to run turbines to produce electricity, and quite a bit of it too: according to the Matter Network story, the new plant in Ottawa will convert 400 tons of waste per day into power for about 19,000 homes.Â
