Union Oil Company of California

Charles F Griswold

Delwin E Cobb

Chien-Cheng J Shih

Ben A Christolini, Jr

Apparatus for the mixing and cooling of hot, particulate matter, such as hot, retorted oil shale, comprises a plurality of enclosed, vertically spaced apart, converging vessels through which the material to be mixed and cooled is flowed. At least the lowermost vessel is configured for a packed bed flow of the material and has mounted therein, on a vertical drive shaft, a mixer blade assembly having a plurality of similar mixing blades which are upwardly inclined at an angle, A.sub.1, of between about 30.degree. and about 75.degree. and preferably within about .+-.15.degree. of the sidewall angle of the vessels. The blades are mounted so as to have an angle of attack, A.sub.2, relative to the rotational direction of travel, of between about 20.degree. and about 60.degree.. A constant angle of attack along each mixing blade is assured by making the angle, A.sub.3, between the blade leading edge and the blade base to be related to the blade inclination and attack angles in accordance with the relationship:

Mixing and cooling apparatus for hot, particulate matter

A two-stage process for staged combustion of crushed retorted particles, especially sulfur and nitrogen-bearing shale, provides maximum heat from combustible materials in shale while emissions of carbon monoxide and oxides of sulfur and nitrogen are minimized. In the first stage, combustion is maintained under fluidizing conditions with a substoichiometric amount of oxygen. Off-gases from the first stage are burned in a second-stage combustion zone utilizing an oxygen-containing gas stream controlled to limit emission of carbon monoxide in the flue gas. To minimize production of sulfur oxides, combustion temperature is concurrently maintained below a peak value of 1700.degree. F. by introducing inert gas or recycled decarbonized fines to the first-stage combustion zone to reduce temperature therein.

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Brea, CA, United States of America

Charles F Griswold