4. Combined cycle

The differences between a combined cycle fuelled by natural gas and a combined cycle fuelled by syngas from gasification are mainly :

• characteristics of the fuel used (composition, calorific value, etc.) ;

• NO _x reduction techniques;

• the combustion turbine, which must be suitable for syngas operation; it must also be able to extract air from its compressor to feed the pressurized air separation unit; some combustion turbines do not offer this facility;

• the steam produced in the gasification and gas treatment section is injected into the water-steam cycle of the IGCC combined cycle.

• extraction of a quantity of medium- or high-pressure steam from the combined cycle's...