TET / ~ L J K l i^i Ι Λ - ^ / ^ Χ / I I - \- I I IN ^ y L V V 7 I
Continuous fluidized carbonization pilot plant for new processes is operated intermit tently to test various coals, to establish yield data, and to evaluate processing equipment
Fluidize Then Carbonize N e w process yields about 25 gallons of liquid prod ucts per ton of fluidized coal; also fields char a n d gas RYE, Ν . Υ.—Continuous fluidized car bonization of coal is a working process that promises to be universally adapt able to all bituminous coals. The growth of this process will depend largely on the interest of the chemical industry in low temperature tar as a raw material. If the past performance of the chemical industry can be used as a barometer, the return of coal as a major source of raw materials may be much nearer than seemed likely even a year ago. This conclusion was reached by Ronald G. Minet of United Engineers & Constructors in his talk before the American Coke and Coal Chemicals Institute. Last year, he says, his com pany built a pilot plant for the con tinuous fluidized carbonization of bi tuminous coal at the Schuylkill Station of Philadelphia Electric. W h e n this pilot plant operates at its full capacity of 2 tons per day, about 1 barrel of liquid products, 1.5 tons of char, and 18,000 cubic feet of gas can be pro duced per day. Since this is a pilot plant for t h e development of a new process, rather than a semiworks plant, it is operated only intermittently to test various coals, to establish yield data, and to evaluate processing equip ment, says Minet. In this process, coal is crushed to pass entirely through an 8-mesh screen in a hammer mill (over 8 7 % of the coal is within the range of 30 to 200 mesh ) . This pulverized material is continuously charged into the fluid ized b e d in the preoxidizer. There, it is rapidly mixed with partially de2376
v o l a t f e e d char, dried, h e a t e d to 700° to 800° F., a n d r e n d e r e d noncoking. T h e heat for this step is supplied partly b y internal combustion in t h e fluidized b e d and partly by electric strip heaters on the shell of the vessel. I n a com mercial plant, the h e a t would b e pro vided b y internal combustion and the h e a t of t h e inlet air. The partially devolatilized char then flows to> the carbonizer, where carbon ization takes place between 800° and 1200° F . AD of t h e h e a t required for this step is provided by the reaction of carbon a n d oxygen in t h e fluidized bed. Steam maintains t h e t e m p e r a t u r e and provides additional rnixing. Depending on the source of the bituminous coal, t h e yields per ton of coal range from 22 to 2 7 gallons of tar, 3 to 4 gallons of light oil, and 1300 to 1450 pounds of char. This char can b e used as a fuel, as a r a w material for gas production, or as a chemical re ducing agent. The sulfur content of t h e char is usually 2 0 to 3 0 % less than that of the r a w coal. T h e char is free flowing, dry, and easy t o handle, says Minet, Sulfur from Oven Gas. In the steel industry, a large proportion of t h e sulfur i n coke oven gas can be used economically for the manufacture of sulfuric acid, says J. K. Kurtz of Bethle h e m Steel, if a substantial quantity of sulfur c a n be recovered, if removal of unis siiixijr is reqinrc
