This process is a two-stage, entrained-flow, slagging process for conversion of lignite and subbituminous coal. The preheated water slurry of coal is fed to the first stage where it is mixed with oxygen, the feed rate of which is controlled to maintain the reactor temperature in a specific range, depending on the properties of the coal. The second stage reduces the temperature of the raw product gas to about 1000°C. The coal is almost completely converted to carbon monoxide, carbon dioxide, and hydrogen.

IGT’s U-GAS Process

Tampella Corporation is commercializing the U-GAS process, which was devel­oped by the Institute of Gas Technology. Tampella has constructed a 10-MW, integrated U-GAS-combined cycle power plant in Finland that uses coal, peat, and wood wastes as feedstocks. U-GAS incorporates a single-stage, fluid-bed gasifier in which coal reacts with steam and air at 950 to 1090°C at pressures from atmospheric to 3.55 MPa to yield a low-energy gas. Oxygen can be substituted for air, in which case a medium-energy gas is produced.