Gasifier Study for Mobil Coal to Gasoline Processes. Final Report

摘要

In a previous paper, it was shown that the indirect route via gasification and synthesis provides a very promising route for high grade fuels, both for the near range and for the long range. The gasifiers and the associated offsites that produce the synthesis gas are a large part of the cost of a complex to produce high quality transportation fuels. The thermal efficiency of this gasification step is also a large contribution to the overall thermal efficiency of the complex. To fully utilize the advantage of this route, it is important to develop better gasifiers and to match the synthesis processes such that they take full advantage of such a gasifier. The objective of this study was to evaluate which of the gasifiers presently under development could meet this goal. This study shows that synthesis gas at the lower ratios of H sub 2 to CO and steam to oxygen has inherent thermal efficiency advantages which arise from basic scientific and engineering principles. Gasifiers that can be made to operate consistent with these principles have a substantial cost advantage. The cost advantages are demonstrated by a differential economic analysis essentially independent of the absolute values of the cost basis. The British Gas Corporation-Lurgi slagging gasifier, which is present close to commercialization, conforms closely to the basic requirement and potentially could produce syngas at a low production cost relative to other gasifiers such as the dry ash Lurgi gasifier. The H sub 2 to CO and steam to oxygen ratios of this gasifier are about 0.5 to 1.3, respectively, very close to the best theoretical values of 0.45 and 1.6, respectively. The low H sub 2 to Co ratio gasifiers have to be matched with syngas conversion processes that use such low ratios. (ERA citation 04:051010)