There are a number of perceptions within the marketplace regarding plasma arc treatment and plasma arc gasification processes. Last week, this blog addressed the idea/claim regarding the plasma arc technology’s ability to generate significant useable recyclable end-products and energy with no residual waste.

This week we address some aspects of the environmental footprint associated with plasma arc gasification processes

The high temperatures within plasma arc gasification reactors do facilitate higher thermal destruction with regards to volatizing organic material in the feedstock and breaking them down to simple molecules, however some plasma arc gasification systems require a secondary reactor or cracking stage to accomplish this breakdown indicating that not all reactions occur within the “blackbox.”

With regards to lower emissions claims, specifically dioxins for example, the high temperature within the plasma arc gasification reactors, while important, alone does not ensure little to no dioxin formation, the rapid cooling of the syngas as it leaves the plasma arc gasification reactor is equally important to ensure these complex compounds do not reform.

As discussed in this blog entry:

Plasma Arc Gasification and Wastewater Other Residuals

http://www.peat.com/blog/plasma-arc-gasification-and-wastewater-other-residuals/

other by-products generated during the gas cleaning and conditioning require proper handling. In some plasma arc gasification process configurations, it is feasible to re-inject the by-products collected/generated during this stage into the plasma arc gasification reactor to be vitrified, however this requires planning during the early design stages. If these by-products cannot be re-fed, then secondary treatment would be mandatory.

There are a number of perceptions within the marketplace regarding plasma arc treatment and plasma arc gasification processes. Two weeks ago, this blog addressed the smaller physical footprint with regards to plasma arc gasification waste-to-energy systems.

This week we discuss the idea/claim regarding the plasma arc technology’s ability to generate significant useable recyclable end-products and energy with no residual waste.

Certainly this depends on the waste feedstock; however it is worth noting that if metals and glass are processed simultaneously in a plasma arc system, additional processing would be required to separate out these products for any re-use potential. The re-use of the vitrified slag product generated from to plasma arc systems has been demonstrated commercially in France and Japan.

Depending on the feedstock and moisture content and plasma utilization (combustion vs. plasma gasification/ plasma pyrolysis), to plasma arc gasification waste-to-energy systems can require significant amounts of energy to operate as such the net energy claims made by some within the industry may be overly optimistic in theory and largely unproven at this point in time in commercial operations. Criticizing the electrical loads associated with processing municipal solid waste in a plasma gasification waste-to-energy system may be valid as the primary goal would be net energy production, however when it comes to industrial, hazardous and universal waste treatment, the primary goal is destruction efficiency and thus the electrical consumption/generation should be considered secondary. Energy balances associated with to plasma-arc gasification waste-to-energy systems should to be reviewed on a project-by-project basis, rather than at a macro level within the industry.