Coal Gasifiers in Waste Service
One example of a process that was originally developed for coal feeds but that has been successfully adapted for municipal solid waste (MSW) or refuse derived fuel (RDF) service is the BGL moving-bed slagging gasifier described in Section 5.1. A 650 t/d unit is in service for waste gasification at the Schwarze Pumpe facility in Germany, where it is part of a larger complex producing electric power and methanol. The plant operates with a 75% waste/ 25% coal feedstock (Greil etal. 2002). Two other projects using this technology are in planning in the United States (Lock — wood and Royer 2001).
A second technology with many references in coal combustion service that was later adapted for waste gasification is the circulating fluid-bed (see Section 5.2.3). Examples are a plant in Riidersdorf near Berlin, which produces some 50,000 Nm3/h low Btu gas for a cement kiln from a wide variety of wastes (Greil et al. 2002), and one at Geertruidenberg in The Netherlands where waste wood is gasified to syngas that is fired in a 600 MW coal-fired power unit.
A third example is the HTW process (Section 5.2.4), for which a 20t/d pilot MSW gasifier has been built by Sumitomo in Japan. Although the HTW process operates in a nonslagging mode, it is possible to add a separate slagging unit into the process, should this be appropriate (Adlhoch etal. 2000).
A final example is the liquid waste gasification of organic nitrogen compounds at Seal Sands using the Noell gasifier (Schingnitz etal. 2002).
Waste Addition to Coal Gasifier Feed
A number of other processes have demonstrated that they can accept small quantities of waste in the feed. For example, in the Shell Coal Gasification unit in Buggenum, 12% waste biomass has already been added to the fuel and plans are in progress to increase this amount (Hannemann etal. 2002).