In recent years, interest in coal gasification has increased significantly. The considerable increase in the price of crude oil and natural gas and concerns about their security of supply have focused attention on whether fuel for the power industry and feedstocks for the chemical industry could be obtained from the gasification of coal. In particular, the rapid economic growth in China has driven a huge demand for gasification to produce chemicals and fertilisers from its extensive and relatively inexpensive coal reserves.

Interest in the gasification of coal for power generation resulting from economic and environmental considerations began in the 1970s. Companies such as Texaco, Shell and Dow made major technical advances in the development of high pressure, entrained flow gasifiers in order to replace increasingly expensive natural gas with coal-derived syngas. In 2007, in all there were 420 gasifiers in 142 operating plants worldwide of which 55% used coal as feed and 32% petroleum residue. About 44% of the total syngas from these gasifiers was used to produce chemicals, 30% to produce liquid fuels and 18% for power generation. There were 45 operating plants gasifying coal in 212 gasifiers with a gasification capacity of 30,825 MWth of syngas. The majority of coal gasification plants constructed in the recent past have been in China for the chemicals industry and this trend is likely to continue in the near future. Considering the growth planned between 2008 and 2010, it is expected that there will be seven new coal plants with ten gasifiers producing 4690 MWth of syngas. These data only include gasifiers utilising internationally-recognised technologies and do not include, for example, the thousands of small communal gasifiers in China.

The development of IGCC plant in the 1980s was the result of integrating gasification technology with a combined cycle plant. Such IGCC coal-fired plants have high efficiencies and produced low emissions. The main impetus for the interest in IGCC technology has included the adoption of increasingly stringent emissions legislation, concerns about the security of natural gas supplies and the desire to retain coal as part of a national energy portfolio. Further impetus has resulted from increasing concerns regarding the emissions of CO2 from power plant. As the concentration and pressure of CO2 in shifted syngas in an IGCC plant is much greater than in the flue gas of a pulverised coal combustion (PCC) power plant, CO2 removal is considerably easier in the former.
This report by Rohan Fernando considers the fundamental chemical processes occurring in a gasifier, discusses the use of coal gasification in the chemicals industry and for the production of liquid fuels, and the operational issues that have arisen in the use of these gasification technologies in IGCC systems.

Coal gasification
Rohan Fernando
CCC/140, ISBN 978-92-9029-459-7, October 2008
£255 non-member countries
£85 member countries
£42.50 educational price