Thermal cracking with hydrogen donor diluent
AssigneeMobil Oil Corporation
InventorsFrancis J. Derbyshire, Philip Varghese, Darrell D. Whitehurst
Life of this patent
Estimating the term…
Abstract
An improved hydrogen donor for hydrogen donor diluent cracking is provided by extraction with naphtha from the cracked product and hydrogenation by hydrogen transfer from a lower boiling hydrogen donor such as tetralin.
Claims13
In a process for hydrogen donor diluent cracking of heavy hydrocarbon charge stock by mixing said charge stock with a hydrogen donor stream containing hydrogenated condensed ring aromatic compounds and reacting the mixture at thermal cracking conditions under hydrogen pressure, the improvement which comprises separating from the product of said hydrogen donor diluent cracking a fraction boiling above about 600.degree. F., separating a heavy aromatic portion from said fraction by extraction with a hydrocarbon naphtha containing 10 to 50 percent by weight of aromatic compounds, hydrogenating said heavy aromatic portion by reacting the same with lower boiling hydrogenated condensed ring aromatic compounds under hydrogen transfer conditions, separating said lower boiling condensed ring aromatic compounds from the hydrogenated heavy aromatic portion resulting from the reaction to generate hydrogen donors from condensed ring aromatic compounds therein, and recycling the hydrogenated heavy aromatic portion to provide said hydrogen donor stream.
An improved hydrogen donor diluent cracking process for hydro-treating heavy hydrocarbon charge stock comprising the steps of
- (a) contacting the hydrocarbon charge stock in the substantial absence of cracking catalyst with a hydrogen donor containing hydrogenated condensed ring aromatic compounds under hydrogen pressure and thermal cracking conditions at a temperature of about 650.degree. F. to 900.degree. F.;
- (b) distilling the cracking product of step (a) to separate a fraction boiling above about 600.degree. F.;
- (c) extracting from said fraction a heavy aromatic portion by contacting said fraction with liquid hydrocarbon naphtha containing about 10 percent to 50 percent by weight of aromatic compounds, wherein said naphtha comprises a mixture of hydrocarbon boiling between about 85.degree. F. and 430.degree. F.;
- (d) reacting extracted heavy aromatic portion from step (c) with at least one lower boiling hydrogenated condensed ring aromatic compound under hydrogen transfer conditions;
- (e) separating hydrogenated heavy aromatic portion from the reaction product of step (d);
- and
- (f) recycling hydrogenated heavy aromatic portion from separation step (e) to cracking step (a).
In the process for hydrogen donor diluent cracking of heavy hydrocarbons wherein a hydrogen donor stream is reacted with hydrocarbon charge under thermal cracking conditions with hydrogen pressure;
- the improvement which comprises reacting a heavy polycyclic aromatic stream with a lower boiling hydrogenated condensed ring aromatic stream under hydrogen transfer conditions;
- fractionating said lower boiling stream from the hydrogenated heavy aromatic stream;
- and introducing said hydrogenated heavy aromatic stream as a hydrogen donor stream to the hydrocarbon charge.
Dependencies are inferred from the claim text.