RE: Global waste-to-energy systems about to ramp
I think that on a large scale, the incinerator or the digester landfills (landfill
gas extraction) make sense if the intent is to do it fast and meet a large
demand for energy, but... I think that gasification combined with plasma
arc gasification is the best approach as far as true efficiency is
concerned.
But, if going for a large scale approach I also think that gasification makes
the most sense. For straight, unsorted MSW a fluidized bed reactor
makes the most sense, but if capital is available for investment in proper
sorting technology then it makes sense to separate the MSW by
feedstock.
By shredding the material down to small sizes and running them under
magnets its easy enough to extract the metals. By steaming it (with waste
steam from the end process) its easy enough to break down the biological
material and separate it from the rest of whats there. In the end its still a
clustered mess, but theres a lot of plastic and other recyclable materials...
when you get the mess of whats left, gasification would allow for syngas to
be extracted which can then be sold as a substitute for natural gas or
converted into transport fuels. It also allows for the dust ash and other
small particulates to be easily filtered out and restored back into the landfill
(taking up much less space and allowing for better, longer lasting
environmental protection against leeching, etc.
The solid materials that are left can then be fed into plasma arc gasifiers
to really break down and separate the non-magnetic metals, rare earth
elements, etc and later sorted again for recycling... as well as allow for the
extraction of more energy.
All of this requires a large initial capital investment and a fairly complex
infrastructure but one that ensures society's waste is ... really no longer
waste, and environmental protection vs just straight incinerators. With
the recycling and the energy extraction, even the large initial investment
will completely pay itself off and be profitable, as well... be environmentally
friendly.
@ ercillor... it also reduces the amount of fossil fuels and other materials
that need to be mined because its using materials that already have been.