Selection of IGCC candidate coals by pilot-scale gasifier operation

Nine imported coal samples were tested to make the guidelines for IGCC (Integrated Gasification Combined Cycle) candidate coals — the guidelines that are applicable in future commercial IGCC plants in Korea. Entrained-bed slagging gasifier whose maximum capacity is 3 ton/day has been operated under pressure ranges of 10–29 bar. The factors considered were conversion efficiencies, moisture content, sulfur content, ash content, ash melting temperature, slag viscosity, slag characteristics, and coal reactivity. The best coal type for IGCC applications appears to be the one that contains low ash content with low-enough slag viscosity and high reactivity in coal. However, coal that exhibits high fluidity at the gasifier exit resulted in higher probability in plugging by fly-slag, so that the coal of ash fluid temperature lower than 1260 °C would require precaution for utilizing the feedstock in the entrained-bed gasifier. Conventional ash fusion measurement data might disagree with slag viscosity results in estimating the optimal operation temperature, and thus actual viscosity tests on slag would be necessary.