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US 4,363,716 AGranted
Cracking of heavy carbonaceous liquid feedstocks utilizing hydrogen donor solvent
OwnerMarvin I. Greene, Abraham P. Gelbeininventors
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Abstract
Heavy carbonaceous liquid having a melting point below 250.degree. C. is upgraded to lighter products by hydrogen donor solvent cracking, using recycled solvent derived at least in part from a middle distillate fraction of either the heavy carbonaceous liquid or from the cracked products which is subjected to one or more catalytic hydroprocessing steps before recycling.
Claims7
A hydrogen donor solvent cracking process for upgrading heavy carbonaceous liquids having a melting point below 250.degree. C. to lighter products comprising in serial combination the steps of:
- (a) adding a stream of hydrogen-donating material, obtained as stated hereinafter, and heavy carbonaceous feedstock in weight ratio of at least 0.25 part of hydrogen-donating material per part of heavy carbonaceous feedstock, to a cracking reaction zone, free of externally-supplied catalyst;
- (b) heating the reaction mixture resulting from step (a) in said cracking zone at a temperature of 250.degree. C. to 800.degree. C. for a total residence time at the specified temperature of from 15 seconds to 5 hours to produce hydrogen-enriched cracked products;
- (c) removing the resulting products from the cracking reaction zone and recovering therefrom a middle distillate fraction boiling in the range of 175.degree. C. to 300.degree. C. atmospheric equivalent temperature;
- (d) subjecting said middle distillate fraction to a selective hydrogenation step in the presence of a solid based metal catalyst thereby adding hydrogen to obtain a replenished hydrogen-donating material richer in hydrogen containing at least 30% by weight of 2-ring hydroaromatics having 10 to 20 carbon atoms per molecule;
- (e) hydroisomerizing said replenished hydrogen-donating material in the presence of a solid acidic catalyst;
- (f) recycling said hydrogen-donating material obtained in step (d) to the cracking zone specified in step (a);
- and
- (g) recovering, from the products produced in said cracking zone, cracked light products boiling below 482.degree. C.
5 more elements
A method of processing crude petroleum comprising in combination the steps of:
- (i) distilling said crude petroleum to provide a virgin middle distillate boiling in the range of 175.degree.-300.degree. C. and a carbonaceous resid which is liquid at 100.degree.-250.degree. C.;
- (ii) feeding said resid, molecular hydrogen, and a recycle stream of hydrogen donor solvent to be obtained as hereinafter described to a cracking zone where said materials are heated in the absence of added catalyst at a temperature of 250.degree.-800.degree. C. for a residence time of 15 seconds to 5 hours to produce hydrogen-enriched cracked products;
- (iii) distilling the cracked products to provide a solvent fraction boiling at 175.degree.-300.degree. C. for use in preparing recycle solvent;
- (iv) subjecting the solvent from step (iii) to hydroprocessing in the presence of molecular hydrogen selected from (A) selective hydrogenation in the presence of a solid base metal catalyst, and (B) hydrogenation in the presence of a solid base metal catalyst followed by hydroisomerization in the presence of a solid acidic catalyst, whereby the content of 2-ring hydroaromatics having 10 to 20 carbon atoms per molecule is increased to at least 30% by weight;
- (v) subjecting the said virgin middle distillate from step (i) to dehydroisomerization in the presence of a noble metal catalyst or a sulfur-resistant reforming catalyst to render said virgin middle distillate rich in 2-ring aromatics;
- (vi) adding the dehydroisomerized middle distillate from step (v) to the recycle solvent prior to step (iv) as a makeup stream;
- (vii) recycling the combined recycle and makeup materials from step (iv) as the hydrogen donor solvent to step (ii);
- and
- (viii) recovering from the cracked products from step (ii) hydrogen enriched lighter products.
6 more elements
Dependencies are inferred from the claim text.