With a net electrical output of 300MW, the ELCOGAS power plant in Puertollano (Ciudad Real. Spain) is the world's highest capacity integrated gasification combined-cycle power plant based on coal. The gas-side corrosion performance of the alloy 28 tubing installed in the high-pressure (HP) exchangers is being evaluated. Corrosion metal losses of samples with more than 18000 operating hours are available, providing acceptable long-term service of this material in the gasifier atmosphere. In addition, failure analysis of different components and materials from the gasifier of the ELCOGAS plant has been performed. The analyzed components are two alloy 600 rupture discs from the gasifier safety valves, an alloy X piece from the quench pipe mechanical hammers and an alloy 800 plate from the evaporator. Taking into account the information related to plant operation, some conclusions about the root causes of the failures are reported in this paper.