US 4,069,132 A · Oil shale retorting process with desulfurization of flue gas

Abstract

A method is provided for retorting oil shale whereby full utilization of the heat energy available in the retorted shale and maximum desulfurization of the flue gas released to the atmosphere are simultaneously effected. Basically, the process comprises passing a crushed shale feed upwardly through preheating and retorting zones in a retort vessel wherein eduction of shale oil and product gases is achieved by direct heat exchange with a preheated, recycled portion of said product gases passed countercurrently to the shale feed, and then passing the retorted shale downwardly through combustion and cooling zones. Complete combustion of coke on the retorted shale in the combustion zone not only results in full utilization of the potential heat energy stored within the retorted shale but also in the production of gaseous sulfur components (mostly SO.sub.2) that chemically react with the alkaline components of the shale. Concurrent flow of gas and retorted shale in the combustion zone at temperatures between 900.degree. and 1670.degree. F permits the reaction between said SO.sub.2 and the alkaline components of the shale to proceed essentially to completion, thus desulfurizing the flue gas produced in said combustion zone.

Claims23

Dependent claims

In a continuous process for combusting coke on retorted oil shale wherein a stream of hot retorted oil shale containing alkaline mineral components, coke, and sulfur components is passed to a combustion zone to combust said coke, the combination of improvements comprising:

1. passing said stream of hot retorted oil shale through said combustion zone concurrently with a stream of gas comprising oxygen, said combustion zone being maintained at a temperature between about 900.degree. and 1670.degree. F and said gas being supplied in sufficient quantity and under conditions correlated with the feed rate of said shale and the temperature maintained in said combustion zone so as to:
a. continuously combust at least some of said coke in said hot retorted oil shale passing through said combustion zone;
and
b. continuously react essentially all gaseous sulfur components produced during the combustion of step (1) (a) with sufficient of said alkaline mineral components to form stable inorganic salts;
and
2. discharging from said combustion zone an oxygen-containing flue gas essentially free of sulfur compounds.

3 more elements

In a continuous process for retorting oil shale wherein a stream of raw, crushed oil shale is countercurrently contacted in a retorting zone with a stream of a hot, essentially oxygen-free education gas, thereby educing from said oil shale a gaseous mixture from which a liquid shale oil product and a product fuel gas are subsequently separated, and producing from said retorting zone a hot, retorted shale containing alkaline mineral components, coke, and sulfur components, the combination of improvements comprising:

1. introducing at least a portion of about retorted shale into combustor means wherein said retorted shale is passed in succession through a combustion zone and a cooling zone, said combustion zone being maintained at a temperature between about 900.degree. and 1670.degree. F;
2. passing an oxidation gas comprising oxygen concurrently with said retorted shale passing through said combustion zone, said gas being supplied in sufficient quantity and under conditions correlated with the feed rate of said retorted shale and the temperature maintained in said combustion zone so as to:
a. continuously combust essentially all of said coke in said retorted shale passing through said combustion zone;
and
b. continuously react essentially all gaseous sulfur components produced during the combustion of step (2) (a) with sufficient of said alkaline mineral components to form stable inorganic salts;
3. maintaining said eduction gas and all gases within said combustion zone separately from each other;
4. discharging from said combustion zone an oxygen containing flue gas essentially free of sulfur compounds;
and
5. passing a cooling gas countercurrently with the decarbonized shale passing through said cooling zone, thereby cooling said decarbonized shale and heating said cooling gas.

6 more elements

Dependencies are inferred from the claim text.

Oil shale retorting process with desulfurization of flue gas

Life of this patent

Oil shale retorting process with desulfurization of flue gas

Life of this patent

Abstract

Claims23