93.     ATWELL, H. V.  Koppers Powdered-Coal Gasification Process.  FIAT Final Rept. 1303, 1947, 51 pp., 16 figs.

                Experimental work on the gasification of powdered coal was conducted from 1938 to 1944.  The first unit was set up at Brabag-Schwarzheide in 1938 and subsequent units at Rheinpreussen Shaft IV near Homberg.  In all cases the reactor was a horizontal drum with powdered coal introduced at one or both ends, and the gasifying agent (air or O₂ mixed with steam) was introduced at spaced points along the length of the drum so as to insure turbulent flow of the dust between inlet and outlet.  Preheating of the gasifying medium to about 1,200° was found to be essential, and Cowper stoves were used for this purpose.  Operation was at atmospheric pressure.  By this method a very rapid ignition of the coal dust took place and a temperature of more than 2,000° was obtained.  This accelerated the gasification process so that the coal was gasified to the extent of about 95%.  The final Rheinpreussen unit was estimated to have a capacity of 10 tons of coal per day, but it never operated successfully because of excessive cooling by the water jacket.  Previous units were somewhat smaller, and no runs longer than 5 or 6 hr. had been made.  No commercial units were built, but several proposals were made on the basis of about 0.5 m.³ O₂ consumption and 2 m.³ synthesis-gas production per kg. of coal.  No original experimental records were available to support the claims made for the process.