Desulfurization of Coal in a Fluidized Bed Reactor at Elevated Temperatures, October 1976

(1976) Desulfurization of Coal in a Fluidized Bed Reactor at Elevated Temperatures, October 1976. Iowa State University

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Abstract

The results of an experimental investigation of a fluidized bed process for the gaseous desulfurization of Iowa coal are presented. The experiments were conducted in a batch fluidized bed reactor under essentially isothermal conditions. A special technique was used for rapidly preheating the coal to the reaction temperature. The effectiveness of hydrogen and oxygen in the removal of sulfur from coal was evaluated at temperatures in the range of 220°-410°C, and compared with the desulfurization achieved due to thermal pyrolysis of coal. A statistical parametric study was done to determine the effects of temperature, type of treatment gas and the ash content on weight loss, volatile matter loss and sulfur removal from coal. The reactions of organic and pyritic sulfur were shown to be very temperature sensitive. The removal of organic sulfur is effected only by the thermal decomposition reactions during pyrolysis. Pyritic sulfur reacts appreciably with oxygen or hydrogen at 400°C. The gases evolved from coal due to devolatilization, combustion and desulfurization were analyzed on a mass spectrometer. The sulfurous species identified in the gas were sulfur dioxide, hydrogen sulfide and traces of carbon oxysulfide. Significant quantities of carbon monoxide and carbon dioxide are formed during the oxygen treatment of. coal.