1286a. GUMZ, W. [Present Status and Future Possibilities in Gasification Processes.] Gas- u. Wasserfach, vol. 88, 1947, pp. 129-136; Chem. Abs., vol. 42, 1948, p. 4,729.
Trend of gas production is in the direction of complete gasification with the use of noncoking coals. Water-gas generators are commonly used for synthesis-gas production; the use of O2 is advantageous when this can be generated at a low price. A greatly expanded use of producer gas is seen particularly in steel works owing to the tendency to sell coke-oven gas to super-gas schemes. The Flesch-Winkler gas producer serves as a transition stage between the grate-type producer and the powdered-coal gas producers. In this generator a 1-m. layer of fine fuel is held on a grate by an air pressure of about 4 mm. H2O column. This is gasified for 10-15 min. until a slag layer is formed, which is caused to sink to the grate by introducing steam; this slag is then removed by means of a H2O-cooled stirring arm. The slag removal period requires 1-3 min., which is followed by a purge of 1 min. after which fresh fuel is introduced and gasification continued. Low-grade high-ash fuels are used. The slagging-type producer offers considerable promise for low-grade fuels, especially when combined with metal recovery. A dry air blast is ordinarily used, but this producer can be operated with 2 stages, the upper using saturated air and the lower dry air.