Recovering hydrocarbons from hydrocarbon-containing vapors

A process for recovery of values from hydrocarbon-containing vapors which comprises:

• (a) quenching hydrocarbon-containing vapors having a temperature of at least 700.degree. F. to a lower temperature between about 100.degree. F. and 700.degree. F. in a quench zone by direct contact with a quench liquid consisting essentially of hydrocarbons to form a condensate and a vapor residue from the hydrocarbon-containing vapors, the condensate and quench liquid forming a combined liquid stream;
• (b) mixing a viscosity-lowering liquid comprising hydrocarbons with said combined liquid stream at a weight ratio of said viscosity-lowering liquid to said condensate in the combined liquid stream of from about 0.01 to about 500 to form a mixed liquid, said viscosity-lowering liquid having a viscosity lower than the viscosity of said combined liquid stream;
• (c) cooling a first portion of said mixed liquid to form said quench liquid and recycling said cooled first portion to the quench zone for contacting said hydrocarbon-containing vapors;
• (d) distilling a second portion of said mixed liquid into at least a viscosity-lowering liquid and a high boiling fraction having a higher volume average boiling point than the volume average boiling point of said viscosity-lowering liquid;
• (e) mixing at least a portion of the viscosity-lowering liquid distilled from the second portion of said mixed liquid with said combined liquid stream.
• (f) recovering said high boiling fraction;
• and
• (g) recovering at least a portion of the vapor residue.

A process for recovery of values from pyrolytic vapors having a temperature of at least 700.degree. F. wherein the pyrolytic vapors comprise tars, intermediate boiling hydrocarbons, low boiling hydrocarbons, and entrained finely divided solids which comprises the steps of:

• (a) contacting in a condensation zone of a first quench stage which includes a liquid mixing zone, the pyrolytic vapor with a quench liquid which is a cooled liquid mixture consisting of tars dissolved in intermediate boiling hydrocarbons condensed from a pyrolytic vapor to form a first condensate containing tars and finely divided solids to leave a pyrolytic vapor containing uncondensed hydrocarbons;
• (b) contacting in a second quench stage the pyrolytic vapor containing uncondensed hydrocarbons with a quench liquid to form a second condensate containing intermediate boiling hydrocarbons and a vapor residue;
• (c) separating the vapor residue from the second condensate;
• (d) mixing in the liquid mixing zone the condensate containing tars and finely divided solids from the first quench stage and the second condensate including the quench liquid from the second quench stage with a viscosity-lowering liquid comprising intermediate boiling hydrocarbons to form a mixed liquid;
• (e) separating the finely divided solids from at least a portion of the mixed liquid;
• (f) separating the mixed liquid into a first and a second portion;
• (g) cooling and recycling the first portion of the mixed liquid from the liquid mixing zone to the first quench stage of the condensate zone as the quench liquid;
• (h) recovering a tar fraction from the second portion of the mixed liquid to yield a substantially tar-free viscosity-lowering liquid and intermediate boiling hydrocarbons from the second portion of the mixed liquid by flash vaporization at less less atmospheric pressure;
• (i) returning at least a portion of the substantially tar-free viscosity-lowering liquid to the mixing zone of the condensation zone and mixing the tar-free viscosity-lowering liquid with a combined stream formed from the condensate from the first quench stage, and the second condensate from the second quench stage;
• and
• (j) contacting the vapor residue separated from the second condensate with a cooled condensate containing low boiling hydrocarbons condensed from the vapor residue to condense a low boiling hydrocarbon fraction from the vapor residue.

In a coal pyrolysis process wherein coal is pyrolyzed in a pyrolysis zone to produce finely divided char and a pyrolytic vapor having a temperature of at least 700.degree. F., a process for recovery of values from said pyrolytic vapor which comprises the steps of:

• (a) contacting the pyrolytic vapors in a quench zone with a quench liquid consisting essentially of hydrocarbons, said quench liquid having a temperature sufficiently low to form a condensate and a vapor residue from the pyrolytic vapor, the condensate and quench liquid forming a combined liquid stream;
• (b) mixing a viscosity-lowering liquid comprising hydrocarbons with said combined liquid stream to form a mixed liquid, said viscosity-lowering liquid having a viscosity lower than the viscosity of said mixed liquid, and said mixed liquid having a viscosity lower than the viscosity of said combined liquid stream;
• (c) cooling and recycling a first portion of said cooled mixed liquid as quench liquid to the quench zone for contact with the pyrolytic vapors;
• (d) separating a second portion of said mixed liquid into at least a viscosity-lowering liquid and a high boiling fraction having a higher volume average boiling point than the volume average boiling point of said viscosity-lowering liquid;
• (e) mixing at least a portion of the viscosity-lowering liquid separated from the second portion of said mixed liquid with said combined liquid stream;
• (f) recovering said high boiling fraction;
• and
• (g) recovering at least a portion of the vapor residue.

In a coal pyrolysis process wherein finely divided coal is pyrolyzed in a pyrolysis zone to produce finely divided char and a pyrolytic vapor having a temperature of at least 700.degree. F., a process for the recovery of values from said pyrolytic vapor which comprises the steps of:

• (a) quenching pyrolytic vapor having a temperature of at least 700.degree. F. to a temperature less than the temperature of the pyrolytic vapor and between about 100.degree. F. and 700.degree. F. in a quench zone with a quench liquid consisting essentially of hydrocarbons to form a condensate and a vapor residue from the pyrolytic vapor, the condensate and quench liquid forming a combined liquid stream;
• (b) mixing a viscosity-lowering liquid comprising hydrocarbons with said combined liquid stream to form a mixed liquid, said viscosity-lowering liquid having a viscosity lower than the viscosity of said mixed liquid, and said mixed liquid having a viscosity lower than the viscosity of said combined liquid stream;
• (c) cooling and recycling a first portion of said mixed liquid to the quench zone for contacting said pyrolytic vapors;
• (d) distilling a second portion of said mixed liquid into at least a viscosity-lowering liquid for mixing with said combined liquid stream and a high boiling fraction having a higher volume average boiling point than the volume average boiling point of said viscosity-lowering liquid;
• (e) mixing at least a portion of the viscosity-lowering liquid separated from the second portion of said mixed liquid with said combined liquid stream;
• (f) recovering said high boiling fraction;
• and
• (g) recovering at least a portion of the vapor residue.

A process for recovery of values from hydrocarbon-containing vapors generated in a pyrolysis operation and containing finely divided solids which comprises the steps of:

• (a) contacting hydrocarbon-containing vapors at a temperature of at least 700.degree. F. in a quench zone with a quench liquid consisting essentially of hydrocarbons, said quench liquid having a temperature sufficiently low to form a condensate and a vapor residue from the hydrocarbon-containing vapors, the condensate and quench liquid forming a combined liquid stream containing the finely divided solids;
• (b) mixing a viscosity-lowering liquid comprising hydrocarbons with said combined liquid stream to form a mixed liquid, said viscosity-lowering liquid having a viscosity lower than the viscosity of said mixed liquid, said mixed liquid having a viscosity lower than the viscosity of said combined liquid stream, and said mixed liquid containing the finely divided solids;
• (c) cooling a first portion of said mixed liquid to form said quench liquid and recycling said cooled first portion to the quench zone for contacting said hydrocarbon-containing vapors;
• (d) treating a second portion of said mixed liquid containing finely divided solids with hydrogen;
• (e) separating finely divided solids from the hydrogen treated second portion of said mixed liquid;
• (f) recycling such separated finely divided solids to the pyrolysis zone;
• (g) separating said hydrogen treated second portion of said mixed liquid following separation of the finely divided solids into at least a viscosity-lowering liquid and a high boiling hydrocarbon fraction having a higher volume average boiling point than the volume average boiling point of said viscosity-lowering liquid;
• (h) recycling and mixing at least a portion of the viscosity-lowering liquid with said combined liquid stream;
• and
• (i) recovering said high boiling hydrocarbon fraction.

A process for recovery of values from hydrocarbon-containing vapors generated in a pyrolysis zone and containing finely divided solids which comprises the steps of:

• (a) contacting hydrocarbon-containing vapors which are at a temperature of at least 700.degree. F. in a quench zone with a quench liquid consisting essentially of hydrocarbons, said quench liquid having a temperature sufficiently low to form a condensate and a vapor residue from the hydrocarbon-containing vapors, the condensate and quench liquid forming a combined liquid stream containing the finely divided solids;
• (b) mixing a viscosity-lowering liquid comprising hydrocarbons with said combined liquid stream to form a mixed liquid, said viscosity-lowering liquid having a viscosity lower than the viscosity of said mixed liquid, said mixed liquid having a viscosity lower than the viscosity of said combined liquid stream, and said mixed liquid containing finely divided solids;
• (c) cooling a first portion of said mixed liquid to form said quench liquid and recycling said cooled first portion to the quench zone for contacting said hydrocarbon-containing vapors;
• (d) separating a second portion of said mixed liquid into at least a viscosity-lowering liquid and a high boiling hydrocarbon fraction containing the finely divided solids and having a higher average boiling point than the volume average boiling point of said viscosity-lowering liquid;
• (e) recycling and mixing at least a portion of the viscosity-lowering liquid with said combined liquid stream;
• (f) treating said high boiling hydrocarbon fraction containing finely divided solids with hydrogen;
• (g) distilling the hydrogenated high boiling hydrocarbon fraction under vacuum for forming a light, low boiling fraction and a heavy bottoms fraction which contains said finely divided solids;
• (h) recycling said heavy bottoms fraction containing such solids to the pyrolysis zone;
• (i) recovering said light, low boiling fraction.

A process for recovery of values from pyrolytic vapors having a temperature of at least 700.degree. F. wherein the pyrolytic vapors comprise tars, intermediate boiling hydrocarbons, low boiling hydrocarbons and entrained finely divided solids which comprises the steps of:

• (a) contacting in a condensation zone of a first quench stage which includes a liquid mixing zone, the pyrolytic vapor with a quench liquid, which is a cooled liquid mixture consisting of tars dissolved in intermediate boiling hydrocarbons condensed from the pyrolytic vapor to form a first condensate containing tars and finely divided solids condensed from the pyrolytic vapor, and a second pyrolytic vapor containing uncondensed hydrocarbons;
• (b) contacting in a second quench stage the second pyrolytic vapor containing uncondensed hydrocarbons with a quench liquid to form a second condensate containing intermediate boiling hydrocarbons, and a vapor residue;
• (c) separating the second condensate from the vapor residue;
• (d) mixing in the liquid mixing zone of the condensation zone, the first condensate containing tars and finely divided solids from the first quench stage and the second condensate from the second quench stage with a viscosity-lowering liquid comprising intermediate boiling hydrocarbons to form a mixed liquid;
• (e) separating and cooling a first portion of said mixed liquid to form said quench fluid, and recycling the cooled quench liquid to the first quench zone and the second quench zone;
• (f) separating a second portion of said mixed liquid into at least a viscosity-lowering liquid and a high boiling hydrocarbon fraction containing the finely divided solids and having a higher average boiling point than the volume average boiling point of said viscosity-lowering liquid;
• (g) mixing at least a portion of the viscosity-lowering liquid with the first and second condensate;
• (h) treating said high boiling hydrocarbon fraction containing finely divided solids with hydrogen;
• (i) distilling the hydrogenated high boiling hydrocarbon fraction under vacuum for forming a light, low boiling fraction and a heavy bottoms fraction which contains finely divided solids;
• (j) recycling said heavy bottoms fraction containing finely divided solids to the pyrolysis operation;
• (k) recovering said light, low boiling fraction;
• and
• (l) recovering low boiling hydrocarbons from the vapor residue.