Exxon Research and Engineering Company

William Bartok

John P Longwell

Howard Freund

Ronald Liotta

David W Blair

Adel F Sarofim

Vince J Siminski

Yih H Song

Disclosed is a one-step ion-exchange method for organically bonding alkali and alkaline-earth metals onto coal. The method comprises contacting the coal, at a temperature from about 20.degree. C. to about 100.degree. C. with, (a) an aqueous solution containing cations of one or more metals selected from the group consisting of alkali and alkaline-earth metals, and (b) an oxidizing gas.

Cation ion exchange of coal

Disclosed is a process for combusting coal containing more than 1 wt. % sulfur which process comprises (a) providing a coal containing more than 1 wt. % sulfur and containing an organically bound calcium to sulfur ratio of at least about 0.8 to 1, (b) burning the coal to about 80% to 95% carbon conversion at temperatures greater than about 1,100.degree. C. in a first combustion zone in the presence of an oxidizing agent but under reducing conditions such that the equivalence ratio of coal to oxidizing agent is less than 1.5 but greater than or equal to 1.0, (c) separating the resulting solid effluent from the gaseous effluent from the first combustion zone, and (d) burning the gaseous effluent at a temperature from about 1,000.degree. C. to about 1,500.degree. C. in a second combustion zone under oxidizing conditions. A substantial amount of the sulfur of the coal is captured in the resulting solid effluent.

Partial combustion process for coal

Fuels containing fixed-nitrogen chemical species are combusted in a multi-stage process. The process which converts substantially all of the fixed-nitrogen into molecular nitrogen (and thus avoids the formation of significant amounts of nitrogen oxides from the fixed-nitrogen) comprises six steps: (a) mixing the fuel with at least one first oxidizing agent in amounts such that the equivalence ratio of said fuel to said oxidizing agent is at least about 1.4; (b) partially combusting the mixture resulting from step (a) in at least one first stage at a first temperature of about 1750.degree. to about 2150.degree. K., with a residence time of at least 0.03 second to less than 0.2 second; (c) injecting a free radical agent into the partially combusted mixture of said fuel and said first oxidizing agent; (d) reacting the mixture of said free radical agent and said partially combusted mixture of said fuel and said first oxidizing agent for at least about 0.05 second to about 0.2 second; (e) mixing the reaction products resulting from step (d) with at least one second oxidizing agent in an amount such that the equivalence ratio of reaction products to the total amount of oxidizing agents in the mixture will be about 1.0 or less, such mixing taking place under conditions such that the temperature of the mixture will not exceed about 1800.degree. K.; and (f) completely combusting the mixture resulting from step (e) in at least one second stage at a second temperature of less than about 1800.degree. K.

Multi-stage process for combusting fuels containing fixed-nitrogen

Fuels containing fixed-nitrogen chemical species are combusted in a multi-stage process. The process which converts substantially all of the fixed-nitrogen into molecular nitrogen (and thus avoids the formation of significant amounts of nitrogen oxides from the fixed-nitrogen) consists of four steps: (a) mixing said fuel with at least one first oxidizing agent in amounts such that the equivalence ratio of said fuel to said oxidizing agent is at least about 1.4; (b) partially combusting the mixture resulting from step (a) in at least one first stage at a first temperature of about 1850.degree. to about 2150.degree. K., with a residence time of at least 0.03 second; (c) mixing the combustion products resulting from step (b) with at least one second oxidizing agent in an amount such that the equivalence ratio of combustion products to the total amount of oxidizing agents in the mixture will be about 1.0 or less, such mixing taking place under conditions such that the temperature of the mixture will not exceed about 1800.degree. K.; and (d) completely combusting the mixture resulting from step (c) in at least one second stage at a second temperature of less than about 1800.degree. K.

Growing community of inventors

Westfield, NJ, United States of America

William Bartok