Hello Naresh,

it is a very complex question you are making. It all comes down to economics. If the investment your are proposing will be viable by utilizing all necessary flue gas cleanong procedures to follow the environmental protection legislation in power, then go ahead. Environmental safety always comes with a price tag.

Hello Naresh,

I agree with Malamakis, because it is not good to solve one environmental problem and create more dangerous ones for the society therefore if the technology conform to best available technology and best environmental practices then why not? The economics should not be limited to the input and output products but complete life cycle analysis will be important.

The question has two aspects. First, the engineering to deal with the energy output and the pollution. The second deals with the economics. The big question that concerns me from an engineering standpoint is the need to burn off a substantial amount of water BEFORE there is a net gain in energy the energy produces. The organic fraction of the municipal solid waste is between 60% and 80% water. The pollution is a question of how much money are you prepared to spend to deliver a specific level of air quality. The exhaust from these plants is very corrosive so you must be prepared to replace and upgrade the equipment as part of the commitment to an incineration plant. The bigger economic issue is the organic fraction which is the fuel for the process in question could be converted into multiple industrial chemicals biologically over night using the Managed Ecosystem Fermentation process.

The heating value of MSW mix is nearly 10-12MJ/kg (45MJ/kg for diesel), as this waste is pretty complex traditional gasification poses several issues and hence the high temperature plasma could be most appropriate choice. Alternatively co-firing with a higher heating value (i.e. coal, biomass) can lessen these issues. Temperature always takes care of everything, but of course higher temperature implies lower efficiency (theoretically in IGCC gasification efficiency is near 60%, practically is 45% or even much lower for MSW). Higher temperature gasification produces specific pollutant gases, some tars (unburned hydrocarbons), but a narrower banded of pollutants (NOx, H2S, HCN, Sox, etc) that again current gas cleaning technology can handle. Let me state that treating MSW needs to be a portfolio solution that is several technologies, rather one technology over the other as each technology such as thermochemical (combustion, gasification, pyrolysis), bio-chemical (digestion and fermentation), physco-chemical (transesterification) have their pros and cons. What also works for one community may not work for other. For example while high temperature leads to a near complete conversion and relatively fast and needs high throughput (economy of the scale as small gasifier are inefficient), the digestion however is slow and never been complete. The former however leaves you with fly ash, gas to clean additional to unstable slag or bottom ash whereas the byproduct of the latter is a slug that can be further treated as compost for soil remediation.