Fuel gas environmental impact. Final report sep 76-dec 77

The report gives results of continued investigation and further definition of the potential environmental and economic benefits of integrated coal gasification/gas cleanup/combined gas and steam cycle power plants. Reported refinements in plant operating characteristics lower heat rates and reduce emissions from previous values. An expanded study of plant environmental intrusions includes a look at potentially hazardous trace elements. Comparisons made of integrated plants using air- and oxygen-blown gasifiers favor air-blowing. Careful theoretical design of plants with low temperature sulfur cleanup reduces to marginal levels the performance and cost advantages of plants with high temperature cleanup. If gasifier steam feed rates are kept low in all but fixed bed types, choice of gasifier among other major generic types is not critical to achieving attractive systems using low temperature cleanup. Excessive thermal NOx emissions may be avoided by departing from conventional combustor designs. Fuel NOx and particulates still pose problems with use of high temperature cleanup. Sulfur removal to very low levels is possible with integrated systems, but cost rises rapidly as it becomes necessary to remove most of the COS as well as the H2S.