Hydrogen production from wastes

A process for the conversion of municipal solid waste, automobile shredder residue and other plastic/rubber wastes to hydrogen is described both from a technical and an economic point of view. Pilot-plant and modeling results are tools in the analysis. The conversion is carried out in two major process steps. The first or pre-treatment step is based on pyrolysis and results in an intermediate product containing approximately 90% of the primary feed in a suitable physical form for the second step. This second step is Texacoʹs high-temperature, high-pressure gasifier which is based on partial oxidation and converts the organic components to synthesis gas (CO and H2). Total thermal conversion efficiency for waste to hydrogen is found to be a strong function of feedstock quality. For typical MSW feedstocks, an efficiency of 40–50% is predicted for an integrated process. Fossil-fuel feedstocks such as waste plastics and scrap tires result in efficiencies of the order 60–70%. The cost of produced hydrogen is approximately $15/GJ for typical MSW with a tipping fee of $50/ton, but drops to $6/ton for high-plastics waste that carry a tipping fee of $100/ton.