Allis-chalmers Corporation

George T Lee

Bobby P Faulkner

Michael H Weinecke

Peter L Schumacher

John N Lees, Jr

Paul M Pukita

Roller grate method and apparatus for simultaneously transporting, agitating and exchanging heat with a bed of solid mineral particles has elongated cylindrical horizontal rollers with gas passage apertures therethrough, a hopper for feeding mineral particles onto the rollers and forming a bed having a depth several times greater than the average diameter of the particles; a drive source to rotate the rollers and frictionally engage the cylindrical surfaces with the particles in the lowermost layer of the bed and urge the bed along a path of travel transverse to the axes of the rollers; elongated filler members disposed in the nip between adjacent rollers to prevent the particles from jamming the rollers and to provide resistance to the flow of the bed along said path of travel; and a heat chamber spanning the rollers and a fan for forcing a heat transfer gas stream through the gas passage apertures in the rollers and through the bed as it is being transported, the rollers and the filler members being adapted to continually agitate the particles and to slowly transport the bed past the gas stream at a velocity which is only a minor fraction of the peripheral velocity of the rollers.

Method and apparatus for subjecting mineral particles to gas flow

Method for gasifying cellulosic material comprises feeding cellulosic material into the uphill end of an inclined rotary kiln; transporting a bed of cellulosic material through the kiln and continuously tumbling the bed; withdrawing fuel gas from the uphill end of the kiln so it flows countercurrent to the bed and removes moisture in the drying zone and thermally decompose volatiles in the devolatilization zone; admitting air overbed in the devolatilization zone and only underbed in the gasifying zone; and controlling the mass flow rate of air into the devolatilization and gasifying zones respectively as predetermined percentages of that rate of which is stoichiometric to the cellulosic material fed into the kiln to thereby limit temperature rise, prevent agglomeration and minimize entrainment of solid particles. Air is admitted into the gasifying zone underbed through axially spaced sets of shell ports, and the mass flow rates of air therethrough are regulated as a function of the percentages of carbon in the bed in the portions of the kiln in which the sets of shell ports are disposed to thereby efficiently utilize the air in converting carbon into CO.sub.2, assure that a high percentage of CO.sub.2 is converted into chemical energy in the form of CO, and permit shortening of the kiln.

Method for gasifying cellulosic material

Roller grate apparatus for simultaneously transporting and transferring heat to or from a bed of material particles has elongated cylindrical parallel horizontal rollers rotatably driven in the same direction; filler bars disposed in the nip between adjacent rollers and together with the rollers forming a generally flat surface with constantly moving portions which continually tumble the material particles and urge them thereacross in a direction transverse to the roller axes; gas passage apertures in the rollers which permit a heat transfer gas stream to pass through the rollers; a heat transfer chamber spanning the rollers; and a fan for blowing a heat transfer gas stream through the chamber and the material bed being transported by the rollers.

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West Allis, WI, United States of America

George T Lee