Kinetic Studies on the Pyrolysis, Desulfurization, and Gasification of Coals with Emphasis on the Non-Isothermal Kinetic Method

摘要

The theory of the non-isothermal technique for the study of the kinetics of complex heterogenous reactions has been extended to include reactive flush gases and back reactions of the products, and has been applied to experimental studies of pyrolysis, desulfurization, and gasification of coals in a series of twenty three non-isothermal experiments. In addition, facilities were constructed for isothermal experiments and a series of nineteen runs were conducted, utilizing both fast and slow heating rates to reach the isothermal operating temperature. The variables studied included coal particle size, flush-gas composition, gas flow rates, and the forms of sulfur in the coal. The objectives of the work were to determine kinetics of desulfurization of coal as an aid to the design, operation, and the evaluation of new process systems for practical desulfurization. A series of reaction types have been identified, and their kinetic parameters measured, during pyrolysis of coal in a hydrogen atmosphere. These are: the reaction of volatile organic sulfur with hydrogen; the reaction of pyrite with hydrogen to form sulfide; and the reaction of hydrogen with the sulfide and organic sulfur associated with the fixed carbon. Sulfate in the coal was reduced to sulfide prior to its transformation to hydrogen sulfide. (Author)