Claims
- 1. A two-stage process for the liquefaction of coal, comprising:
- contacting coal with liquefaction solvent in a first stage to produce a first effluent containing 850.degree. F.- material and 850.degree. F.+ material; recovering from the first effluent a feed (mixture) material comprising at least a portion of the 850.degree. F.- material and 850.degree. F.+ material; hydrogenating said feed (mixture) material in a second stage at a temperature of from 650.degree. F. to 795.degree. F. and at an overall conversion, based on 850.degree. F.+ material, of at least 30% and no greater than 60% to produce a second effluent comprising 850.degree. F.- material and 850.degree. F.+ material; recovering from the second effluent a portion of the 850.degree. F.- material as product, and a mixture of 850.degree. F.- material and 850.degree. F.+ material, said mixture having a 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 having an initial boiling point of at least 500.degree. F. recovered from the first stage effluent, and said mixture in an amount from 60% to 100% (of said mixture), all by weight.
- 2. 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%.
- 3. The process of claim 1 wherein the first stage is a short contact time thermal liquefaction.
- 4. The process of claim 1 wherein said ratio of 850.degree. F.- material to 850.degree. F.+ material recovered from the second stage is at least 1:1.
- 5. The process of claim 1 wherein the liquefaction solvent has a hydrogen to carbon ratio of at least 0.95:1.
- 6. 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.
- 7. The process of claim 6 wherein gaseous hydrogen is employed in the first stage and gaseous hydrogen consumption in the first stage is less than 1%.
- 8. The process of claim 7 wherein residence time for the first stage at temperatures above 600.degree. F. is 2 to 15 minutes.
- 9. The process of claim 8 wherein conversion of moisture ash free coal in the first stage is at least 90%.
- 10. The process of claim 9 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.
- 11. The process of claim 1 wherein the coal is bituminous coal.
- 12. A two-stage process for liquefying bituminous coal, comprising:
- contacting bituminous coal with a liquefaction solvent in a first stage to produce a first effluent containing 850.degree. F.- and 850.degree. F.+ material; recovering from the first effluent an essentially ash-free feed material comprising at least a portion of the 850.degree. F.- material and 850.degree. F.+ material; hydrogenating said feed material in a second stage at a temperature of from 650.degree. F. to 795.degree. F. and at an overall conversion, based on 850.degree. F.+ material, of at least 30% and no greater than 60% to produce a second effluent; recovering from the second effluent a portion of the 850.degree. F.- material, as product, and a remaining mixture of 850.degree. F.+ material and 850.degree. F.- material, said remaining mixture having a ratio of 850.degree. F.- material to 850.degree. F.+ material of from 0.8:1 to 6:1; and directly employing said remaining mixture, without additional hydrogenation, as at least a portion of the liquefaction solvent in the first stage, said liquefaction solvent being comprised of said remaining mixture in an amount of from 60% to 100% (of said remaining mixture,) and from 0% to 40% of 850.degree. F.- material recovered from the first effluent, all by weight.
- 13. The process of claim 12 wherein the 850.degree. F.- material from the first stage is present in the liquefaction solvent in an amount of from 5% to 25%.
- 14. The process of claim 13 wherein the first stage is a short contact thermal liquefaction operated at an outlet temperature of from 800.degree. F. to 875.degree. F.
- 15. The process of claim 14 wherein residence time for the first stage at temperatures above 600.degree. F. is 2 to 15 minutes.
- 16. The process of claim 15 wherein 850.degree. F.- material from the first stage is present in the liquefaction solvent in an amount of from 10% to 25%.
- 17. The process of claim 16 wherein conversion of moisture ash free coal in the first stage is at least 90%.
- 18. The process of claim 17 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 (14)