Integrated staged catalytic cracking and staged hydroprocessing process
AssigneeExxon Research & Engineering Co.
InventorsRamesh Gupta, Edward S. Ellis
Life of this patent
Estimating the term…
Abstract
Disclosed is a catalytic cracking process that includes more than one catalytic cracking reaction step. The process integrates catalytic cracking steps with hydroprocessing in order to maximize olefins production, distillate quality and octane level of the overall cracked product. Preferably, one hydroprocessing step is included between the cat cracking reaction steps, and a portion of the hydroprocessed products, i.e., a naphtha and mid distillate fraction, is combined with cracked product for further separation and hydroprocessing. It is also preferred that the first catalytic cracking reaction step be a short contact time reaction step.
Claims14
A catalytic cracking process for producing high quality mid-distillates comprising the continuous steps of:
- (a) contacting a hydrocarbon feed having an initial boiling point of at least about 400.degree. F. with a hydroprocessing catalyst under hydroprocessing conditions in a first hydroprocessor in order to form a first hydroprocessed hydrocarbon;
- (b) conducting at least a portion of the first hydroprocessed hydrocarbon to a first catalytic cracker and contacting the portion of the first hydroprocessed hydrocarbon with cracking catalyst under catalytic cracking conditions wherein the temperature is from 900.degree. to 1150.degree. F. and the catalyst contact time is less than 5 seconds in order to form a first cracked hydrocarbon product;
- (c) conducting the first cracked hydrocarbon product to a first separator and separating from the first cracked hydrocarbon product at least a first naphtha fraction, a first light ends fraction, and a gas oil-containing bottoms fraction having an initial boiling point of at least 300.degree. F.;
- (d) conducting at least the gas oil-containing bottoms fraction to a second hydroprocessor and hydroprocessing gas oil-containing bottoms fraction under hydroprocessing conditions in order to form a second hydroprocessed hydrocarbon, wherein the second hydroprocessor has a higher hydrogen partial pressure than the first hydroprocessor;
- (e) conducting the second hydroprocessed hydrocarbon to a second separator;
- separating at least a fraction containing unspent hydrogen and a hydroprocessed, gas oil-containing bottoms fraction;
- and combining at least the fraction containing unspent hydrogen with the hydrocarbon feed of step (a);
- (f) conducting at least the hydroprocessed, gas oil-containing bottoms fraction to a second catalytic cracker and contacting the hydroprocessed, gas oil-containing bottoms fraction with cracking catalyst under catalytic cracking conditions wherein the temperature is from 950.degree. to 125.degree. F. in order to form a second cracked hydrocarbon product;
- and,
- (g) combining the first cracked hydrocarbon product and the second cracked hydrocarbon product for continued separation and hydroprocessing of at least the gas oil-containing bottoms fraction.
Dependencies are inferred from the claim text.