Plasma pyrolysis and plasma gasification, like incineration, are options for recovering value from waste by thermal treatment. Both pyrolysis and plasma gasification convert feedstocks/wastes into energy by heating the waste under controlled conditions. Whereas incineration converts the input waste into a combusted flue-gas that can then be used to recover thermal energy (usually in the form of steam) and ash, pyrolysis and plasma gasification deliberately limit the conversion so that combustion does not take place directly. Instead, they convert the waste into potentially valuable intermediates that can be further processed for materials recycling or energy recovery. Pyrolysis and plasma gasification offer more scope for recovering products from waste than incineration.

The last blog discussed plasma gasification, however more information on plasma pyrolysis is warranted.

Plasma pyrolysis takes place in reactors where oxygen is either absent or only present in very low concentrations. Pure pyrolysis is rarely used by itself, but followed by a downstream combustion or plasma gasification stage that converts pyrolysis tars into end-products that are more re-usable, such as the synthetic gas or “syngas.”

Plasma pyrolysis and plasma gasification are often used interchangeable because both produce an energy-rich product gas, however they are somewhat different. Some plasma companies convert the tars to carbon monoxide and hydrogen in a secondary cracking reactor (main reason for this two stage is tighter control over the syngas/flue gas production), while in other configurations, the plasma gasification (or partial combustion for some) reactions take place in the very same reactor, thus further blurring the boundaries between the two reactions. PEAT’s Plasma Thermal Destruction and Recovery systems are designed whereabouts plasma pyrolysis and plasma gasification occur in the very same reactor.