CARBON-DIOXIDE RECOVERY USING A DUAL GAS-TURBINE IGCC PLANT

A new scheme is described for electricity production based on coal gasificiation with recovery of CO2. Coal is gasified into a synthesis gas, mainly consisting of hydrogen and carbon monoxide. After cleanup, this synthesis gas is separated by a membrane into a carbon-rich gas and a hydrogen-rich gas. The hydrogen-rich gas is fed to a conventional gas turbine. The carbon-rich gas is fed to another gas turbine, where it is fired in a mixture of oxygen and CO2. The exhaust of the latter is almost pure CO2 and can be stored outside the atmosphere. The CO2 emissions of this plant are about 10% of the emissions of an IGCC plant WithoUt CO2 recovery, and the conversion efficiency is approx. 6% lower. A first estimate is that the electricity production costs are about one third higher. It is found that the specific emission reduction costs can be limited to about $16 per tonne of CO2 avoided. The main technical problem of this new scheme is the development of a new type of gas turbine with CO2 as working fluid.