Claims
- 1. A two-step process for the liquefaction of coal, comprising:
- contacting coal with a liquefaction solvent in a first stage to produce a liquefaction effluent containing 850.degree. F.- material and 850.degree. F.+ material; recovering from the liquefaction effluent feed material comprising at least a portion of the 850.degree. F.- material and 850.degree. F.+ material; hydrogenating feed material in a second stage in first and second hydrogenating zones of said second stage, said first zone being operated at a temperature of from 650.degree. F. to 795.degree. F., the second zone being operated at a temperature of at least 800.degree. F. and no greater than 840.degree. F.; recovering from both the first and second zones a portion of 850.degree. F.- material as product; recovering from both the first and second zones a mixture of 850.degree. F.- material and 850.degree. F.+ material, said mixture having a weight ratio of 850.degree. F.- material to 850.degree. F.+ material of from 0.8:1 to 6:1; and directly employing said mixture, without additional hydrogenation, as at least a portion of the liquefaction solvent used in the first stage, said liquefaction solvent being comprised of from 0% to 40% of 850.degree. F.- material from the first stage effluent, and from 60% to 100% of said mixture, all by weight.
- 2. The process of claim 1 wherein said ratio of 850.degree. F.- material to 850.degree. F.+ material recovered in the mixture is at least 1:1.
- 3. The process of claim 1 wherein the first and second zones are in series with a portion of effluent from the first zone being employed as feed to the second zone.
- 4. The process of claim 1 wherein the first and second zones are in parallel, a portion of the feed material from the first stage being introduced into the first zone and a further portion of the feed material from the first stage being introduced into the second zone.
- 5. The process of claim 1 wherein the 850.degree. F.- material from the first stage is present in the liquefaction solvent in an amount from 5% to 25%.
- 6. The process of claim 1 wherein the first stage is a short contact time thermal liquefaction.
- 7. The process of claim 1 wherein the liquefaction solvent has a hydrogen to carbon ratio of at least 0.95:1.
- 8. The process of claim 1 wherein the first stage is a short contact thermal liquefaction operated at an outlet temperature of from 800.degree. F. to 875.degree. F.
- 9. The process of claim 8 wherein gaseous hydrogen is employed in the first stage and gaseous hydrogen consumption in the first stage is less than 1%.
- 10. The process of claim 9 wherein residence time for the first stage at temperatures above 600.degree. F. is 2 to 15 minutes.
- 11. The process of claim 10 wherein conversion of moisture ash free coal in the first stage is at least 90%.
- 12. The process of claim 11 wherein a mixture of insoluble material and 850.degree. F.+ material derived from the coal is recovered from one of the two stages and further comprising producing hydrogen from the mixture for use in the liquefaction process.
- 13. The process of claim 1 wherein the coal is bituminous coal.
- 14. A two-stage process for liquefying bituminous coal, comprising:
- contacting coal with liquefaction solvent in a first stage to produce a liquefaction effluent, said first stage being a short residence time thermal liquefaction stage; recovering a liquefaction effluent from the first stage containing 850.degree. F.- material and 850.degree. F.+ material; separating insoluble material from the liquefaction effluent; recovering from the liquefaction effluent a feed material comprising at least a portion of the 850.degree. F.- material and 850.degree. F.+ material; hydrogenating feed material in a second stage in first and second hydrogenating zones, said first zone being operated at a temperature of from 650.degree. F. to 795.degree. F. and the second zone being operated at a temperature of at least 800.degree. F. and no greater than 840.degree. F.; recovering from both the first and second zones a portion of 850.degree.- material as product; recovering from both the first and second zones a mixture of 850.degree. F.- material and 850.degree. F.+ material, said mixture having a weight ratio of 850.degree. F.- material to 850.degree. F.- material of from 0.8:1 to 6:1; and directly employing said mixture, without additional hydrogenation, as at least a portion of liquefaction solvent used in the first stage, said liquefaction solvent being comprised of from 0% to 40% of 850.degree. F.- material from the first stage effluent and from 60% to 100% of said mixture, all by weight.
- 15. The process of claim 14 wherein the first and second zones are in series, and a portion of first zone effluent is introduced as feed to the second zone.
- 16. The process of claim 15 wherein the 850.degree. F.- material from the first stage is present in the liquefaction solvent in an amount of from 5% to 25%.
- 17. The process of claim 16 wherein the first stage is a short contact thermal liquefaction operated at an outlet temperature of from 800.degree. F. to 875.degree. F.
- 18. The process of claim 17 wherein residence time for the first stage at temperatures above 600.degree. F. is 2 to 15 minutes.
- 19. The process of claim 18 wherein 850.degree. F.- material from the first stage is present in the liquefaction solvent in an amount of from 10% to 25%.
- 20. The process of claim 19 wherein conversion of moisture ash free coal in the first stage is at least 90%.
- 21. The process of claim 20 wherein gaseous hydrogen is employed in the first stage and gaseous hydrogen consumption in the first stage is less than 1%.
Government Interests
The Government has rights in this invention pursuant to Contract No. DE-AC22-79ETI 4804 awarded by the U.S. Department of Energy.
US Referenced Citations (11)