Removal of carbon monoxide and sulfur oxides from refinery flue gases
AssigneeStandard Oil Company (Indiana)
InventorsHerschel D. Radford, Gerard J. D'Souza
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Abstract
A cyclic fluidized catalytic cracking process is operated with a cracking catalyst which is modified with one or more metal oxides capable of reacting with sulfur oxides in the regeneration zone wherein the catalyst is regenerated under conditions which result in substantially complete conversion of carbon monoxide to carbon dioxide. Tail gases and flue gases from refinery furnaces which contain carbon monoxide and sulfur oxides are conveyed to the regeneration zone where they are scrubbed by the modified catalyst. The sulfur oxides are absorbed and the carbon monoxide is converted to carbon dioxide in the regeneration zone.
Claims26
In a process for the cyclic, fluidized, catalytic cracking of an organic feedstock of the type wherein said feedstock is subjected to cracking in a reaction zone with fluidized solid particles of a cracking catalyst;
- catalyst substantially deactivated by non-volatile coke deposits is separated from reaction zone effluent and stripped of volatile deposits in a stripping zone by contact with a stripping gas which contains steam;
- stripped catalyst particles are separated from stripping zone effluent and regenerated in a regeneration zone by combustion of the coke deposits with an oxygen containing gas;
- and regenerated catalyst particles are separated from regeneration zone effluent gas and recycled to the reaction zone, the improvement comprising:
- (a) conveying at least one waste gas stream containing sulfur oxides to said regeneration zone;
- and
- (b) contacting said waste gas stream with the catalyst particles in said regeneration zone, wherein the catalyst particles are modified with at least one metal oxide which reacts with sulfur oxides in the regeneration zone to form non-volatile sulfur compounds, and wherein said metal oxide is present in sufficient amount to reduce the concentration of sulfur oxides in said waste gas stream.
In a process for the cyclic, fluidized, catalytic cracking of an organic feedstock of the type wherein said feedstock is subjected to cracking in a reaction zone with fluidized solid particles of a cracking catalyst;
- catalyst substantially deactivated by non-volatile coke deposits is separated from reaction zone effluent and stripped of volatile deposits in a stripping zone by contact with a stripping gas which contains steam;
- stripped catalyst particles are separated from stripping zone effluent and regenerated in a regeneration zone by combustion of the coke deposits with an oxygen containing gas;
- and regenerated catalyst particles are separated from regeneration zone effluent gas and recycled to the reaction zone, the improvement comprising:
- (a) conveying at least one waste gas stream containing carbon monoxide and sulfur oxides to said regeneration zone;
- and
- (b) contacting said waste gas stream with the catalyst particles in said regeneration zone, wherein the catalyst employed is modified with at least one metal oxide which reacts with sulfur oxides in the regeneration zone to form non-volatile sulfur compounds, and wherein said metal oxide is present in sufficient amount to reduce the concentration of sulfur oxides in said waste gas stream;
- (c) mixing said waste gas stream with a molecular oxygen-containing gas in the regeneration zone;
- and
- (d) effecting substantially complete combustion of said carbon monoxide to carbon dioxide within said regeneration zone, wherein said modified catalyst particles are present in sufficient amount within said regeneration zone to absorb therein a major portion of the heat derived from combustion of said carbon monoxide and the coke deposits.
Dependencies are inferred from the claim text.