Puertollano IGCC power plant furnishes an efficient pressurised entrained flow (PRENFLO) gasifier built by Krupp-Koppers. The fuel is a mixture of high-ash local coal and high-sulphur petroleum coke at 50% in weight. A small amount of limestone (2%) is added to favour ash fluidisation. The gasifying agents are oxygen (85% purity) and steam. Fuel, oxygen and steam are introduced in the reaction chamber by using four burners. They react very quickly (residence time around few seconds) at high temperatures generating a combustible gas mainly composed of CO and H2 that leaves the reaction chamber by its upper part. Due to the high temperatures, the ash of the fuel becomes slag that flows to the bottom. Walls of the reaction chamber are cooled by boiling water (Fig. 1). Gas leaving the reaction chamber is quenched with a cold gas stream in order to stop gas phase reactions and enter the evaporators with adequate operation conditions.