A review of the applicability of integrated gasification combined cycle in South Africa

Abstract

Integrated Gasification Combined Cycle (IGCC) is a technology that combines a number of components with the aim of producing electricity at high cycle efficiencies and near zero emissions. This research focussed on IGCC with coal as a feedstock in an attempt to establish the applicability of this technology in South Africa. Fluidised bed gasification technology was found to be the fine coal gasification technology in IGCC with greatest potential when considering the qualities of coals currently being used in local power stations. Gasification test work on four selected South African coals was undertaken at the CSIR gasification testing facility, to assess the behaviour and compatibility of these coals with fluidised bed gasification. A further aspect investigated the likely emissions that would be produced and how these compare to the national limits set by the Department of Environmental Affairs. During the course of the literature survey, it became apparent that the reduction of gaseous emissions from IGCC plant will have a significant impact on the economic and environmental aspects and therefore the attractiveness of the IGCC technology. For this reason the research direction turned to investigate in greater detail the emissions generated from the combustion of syngas produced from fluidised bed gasification and combusted in a gas turbine. This serves to be an estimation of emissions that may be expected from the syngas combustion turbine in an IGCC technology. The estimated emissions were used to assess the impact that the selected coals may be expected to have on full scale emissions. It was also established that the agent used in gasifying these coals had an influence on the quality of gas produced. These results are likely to aid in understanding how to control the nature of emissions in future gasification processes with specific application to fluidised bed technology in IGCC processes.