Feasibility study of the conversion of Karachi's municipal solid waste into methanol

Increasingly over the past twenty or thirty years municipal solid waste (MSW) has begun to be recycled for energy production purposes, via incineration, in the U.S., Western Europe, and Japan. In some locations the metals and glass contained in the MSW also are recycled. Interest in this specialized form of energy technology also has begun to emerge in a number of less industrialized countries.

The generation of energy via incineration of MSW has proved to be economically viable in only a limited number of locations, although economic attractiveness of the strategy is likely to increase in the future as the cost to traditional landfill disposal methods escalates.

It appears possible that the combustible portion of MSW might be used as a feedstock for the synthesis of carefully selected chemicals, via intermediate gasification or other appropriate chemical conversion technologies. The chemical production strategy may possibly be more attractive economically than is the energy production strategy.

This thesis examines one available technology for conversion of the combustible portion of MSW into intermediates such as synthesis gas, and the eventual manufacture of methanol (fuel grade). The initial phase of the thesis work is oriented towards selection of a technology for more detailed study.

Although different detailed studies on the gasification of both MSW and biomass are referenced in this study, a Union Carbide MSW gasifier which operated in the mid 1970s provides the only source of operational technical and cost experience that could be located. This is the primary reason for selecting the Purox process for analysis in this study, although there appear to be other technical advantages as well.