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Dr. Green Solid Waste to Energy

By: Stephen Matthews

On Friday August 3rd, Dr. Alex Green came and gave a lecture and a tour regarding SWEATT  or Solid Waste to Energy by Advanced Thermal Technologies. This is a form of pyrolysis that he researches in his lab and advocates for the conversion of solid wastes and biomass into gaseous fuels. He has written guest editorials in the Gainesville Sun advocating the co-utilization of natural gas with syngas in UF's gas turbine. Syngas is a gas made during pyrolysis and has an energy content because it was not fully combusted during pyrolysis. Dr. Green believes that solid waste can contribute more than any other renewable energy source in the near term, because it is already the largest source of renewable energy, and its high availability. Dr. Green estimates that approximately 2 billion tons of dry solid waste is available for pyrolysis and gasification. This equates to about 23 quadrillion BTUs of energy, which is slightly greater than the current amount of energy derived from coal in America. Dr. Green also showed us his pyrolysis/gasification lab. In his lab he has set up the Mk 5.7 PDU, which is an auger driven pyrolyzer. From this piece of equipment that he has built he is able to pyrolyze any solid waste that has a moisture content of under 40% and is of small particle size. He makes the particle size smaller by using a metallic barrel connected to a lawnmower to act like a giant coffee grinder and pulverize the solid waste until it is small enough to go through the pyrolyzer. He has produced gas from wide range of feedstocks such as millerite and MREs or meals ready to eat. Also, the byproducts of pyrolysis such as the bio-oil which consists of liquid hydrocarbons and water, and charcoal can be used to fuel the pyrolysis and generate products such as chemicals and activated charcoal for use in other processes.