Integrated heavy oil pyrolysis process
AssigneeStone & Webster Engineering Corp.
InventorsHerman N. Woebcke, Swami Narayanan, Axel R. Johnson
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Abstract
A process and system for the production of olefins from heavy hydrocarbon feedstocks. A heavy hydrocarbon feed is first pretreated at high pressure and moderate temperatures to preferentially remove coke precursors in a liquid product. The pretreated hydrocarbon is then separated into lighter and heavier fractions; the lighter fraction being further thermally cracked to produce olefins.
Claims25
A process for converging heavy hydrocarbon feedstocks to olefins comprising the steps of:
- (a) cracking in a pre-pyrolysis cracker the heavy hydrocarbon feedstock at pressures above 150 psig;
- temperatures above 850.degree. F. and residence times of 0.5 to 3 minutes;
- (b) subjecting the cracked feedstock to a pressure drop;
- (c) separating the cracked feedstock into a lighter hydrocarbon fraction and a heavier hydrocarbon fraction;
- and
- (d) thermally cracking the lighter hydrocarbon fraction to produce olefins.
A process for converting heavy hydrocarbon feedstocks to olefins comprising the steps of:
- (a) preheating the heavy hydrocarbon feedstock to a temperature of 750.degree. F.;
- (b) thermally pretreating the heavy hydrocarbon feedstock at a pressure of 400 psig and a temperature of 980.degree. F.;
- (c) subjecting the pretreated feedstock to a pressure drop of 300 psig;
- (d) separating the pretreated feedstock into a light overhead fraction, a heavy hydrocarbon fraction and a middle hydrocarbon fraction;
- and
- (e) thermally cracking the light overhead fraction and said middle hydrocarbon to produce olefins.
A thermal treatment process for producing olefins from heavy hydrocarbon feedstocks comprising:
- (a) thermally pretreating the heavy hydrocarbon feedstock at residence times of 0.5 to 3 minutes and temperatures above 850.degree. F. whereby olefin precursors are separated from their aromatic linkages as demonstrated by reducing both the weight and hydrocarbon concentration in the higher boiling point fraction;
- (b) separating the thermally pretreated heavy hydrocarbon feedstock into a lighter olefin precursor concentrate and a heavier carbon rich fuel product;
- and
- (c) cracking said precursor concentrate to produce olefins.
Dependencies are inferred from the claim text.