Perspectives on the Gasification of Urban and Industrial Wastes

Gasification is a technological option for the production of synthetic gas (SG) via partial oxidation of organic matter such as, residual biomass, sorted urban wastes (RDF) and industrial wastes. The synthetic gas, after appropriate conditioning, can be used either directly or mixed with natural gas (NG) for heat or electricity co-generation. If electricity production is the final option the useof gas turbines or Diesel motors at high compression rates is required. A novel alternative is to shift convert/reform the synthetic gas to H.sub.2 and CO.sub.2 with its final utilization in a fuel cell. The elctrical conversion efficiency will reach 40-50%. Gasification has three main technological advantages over combustion: a) the energy conversion efficiency of gasification for theproduction of electricity is higher than from combustion; b) the quantities of air used and of gas produced are lower than in combusion, thus leading to lesser operational costs (see gas conditioning); and, c) the synthetic gas produced can either be used in situ or appropriately stored and transported at moderate distances. The scientific and technological advances in this area, made by ourresearch group during the last year, will be presented and discussed in this paper. These advances suggest the possibility of this option (gasification) for the disposal of wastes with energy recovery; the fact that both the controlled combustion and landfilling options face increasing social pressure and costs, combined with the high efficiency energy recovery and flexibliity of thegasification option, render this solution particularly attractive, especially when applied to small-to-medium scale waste disposal problems.