Retorting process

• US 4,455,217 A
• Filed: 11/25/1981
• Issued: 06/19/1984
• Est. Priority Date: 11/25/1981
• Status: Expired due to Fees

• Current Assignee: Chevron Research Company (Chevron Corp.)
• Original Assignee: Chevron Research Company (Chevron Corp.)
• Inventors: Reynolds, Bruce A.
• Primary Examiner(s): Shine, W. J.
• Assistant Examiner(s): Caldarola, Glenn A.
• Application Number:
  US06/324,793
• Time in Patent Office: 937 Days
• Field of Search: 208/11 R, 208/8 R
• US Class Current: 208/410
• CPC Class Codes: C10G 1/02 by distillation

Abstract

Fines in the overhead vapors from an oil shale retort process in which fresh shale together with hot recycle combusted shale from a combustor are fed to a retort and at least partly fluidized by a countercurrent stripping gas stream are handled by (a) removing a portion of the fines in a vapor-solid separation (b) optionally subjecting the portion of fines to additional retorting in a fines retort (c) condensing the partially dedusted gas (d) separating the condensate into a substantially fines-free liquid oil and a wet solids and (e) recycling at least a portion of the wet solids to the retort, fines retort, and/or combustor whereby the liquid on the wet solids is recovered and/or burned and the wet solids are dried.

Claims

1. In a retort process comprising:

introducing fresh hydrocarbon-containing solids having a maximum particle size less than about one cm into the upper portion of a retorting zone;

introducing a particulate heat transfer material at an elevated temperature into the upper portion of the retorting zone;

introducing a nonoxidizing stripping gas into the lower portion of the retorting zone at a linear velocity that fluidizes at least a portion of the fresh hydrocarbon-containing solids and heat transfer material dropping through the retorting zone and causes mixing therebetween whereby sufficient heat is transferred from the heat transfer material to the fresh hydrocarbon-containing solids to heat the hydrocarbon-containing solids to a temperature at which retorting occurs;

withdrawing a mixture of retorted solids and heat transfer material from the retorting zone and introducing it into a combustion zone wherein the char on the retorted solids is combusted to heat the heat transfer material to said elevated temperature;

withdrawing an overhead stream from the upper portion of the retorting zone that comprises stripping gas, the vapors of retorting, and entrained fines having a maximum particle size less than about 250 microns;

removing a portion of said fines from the overhead stream, said portion being comprised predominantly of particles having a particle size greater than about five microns;

thereafter condensing the overhead stream to produce a liquid condensate containing substantially all of the entrained fines remaining in the stream, and removing fines from the condensate to produce a liquid oil product and wet solids, the improvement comprising recycling at least a portion of the wet solids into the combustion zone whereby the condensate component of the wet solids is combusted and the fines component of the wet solids is dried in contact with the mixture of the heat transfer material and the retorted solids.

2. The process of claim 1 wherein the hydrocarbon-containing solids is oil shale.

3. The process of claim 2 wherein the heat transfer material is combusted oil shale.

4. The process of claim 3 wherein the weight ratio of combusted oil shale to fresh oil shale is about 1.5:

1 to about 8;

1 and said elevated temperature is about 450°

C. to about 750°

C.

5. The process of claim 3 wherein said linear velocity is in the range of about 0.2 to about 1 m/sec.

6. The process of claim 3 wherein the amount of fines in the overhead stream is about 0.5 to five times the amount of vapors in the overhead stream, by weight.

7. The process of claim 3 wherein the liquid oil product contains less than about 10% by weight fines and the wet solids contains less than 40% by weight condensate.

8. The process of claim 4 wherein said linear velocity is in the range of about 0.2 to about 1 m/sec, the amount of fines in the overhead stream is 0.5 to five times the amount of vapors in the overhead stream by weight, the liquid oil product contains less than about one % by weight fines and the wet solids contains less than 10% by weight condensate.

9. In a retort process comprising:

introducing fresh hydrocarbon-containing solids having a maximum particle size less than about one cm into the upper portion of a retorting zone;

introducing a particulate heat transfer material at an elevated temperature into the upper portion of the retorting zone;

introducing a nonoxidizing stripping gas into the lower portion of the retorting zone at a linear velocity that fluidizes at least a portion of the fresh hydrocarbon-containing solids and heat transfer material dropping through the retorting zone and causes mixing therebetween whereby sufficient heat is transferred from the heat transfer material to the fresh hydrocarbon-containing solids to heat the hydrocarbon-containing solids to a temperature at which retorting occurs;

withdrawing a mixture of retorted solids and heat transfer material from the retorting zone and introducing it into a combustion zone wherein the char on the retorted solids is combusted to heat the heat transfer material to said elevated temperature;

withdrawing an overhead stream from the upper portion of the retorting zone that comprises stripping gas, the vapors of retorting, and entrained fines having a maximum particle size less than about 250 microns;

removing a portion of said fines from the overhead stream, said portion being comprised predominantly of particles having a particle size greater than about five microns;

subjecting the portion of the fines removed from the overhead to additional retorting in a second retorting zone and combining the vapors from the second retorting zone with said overhead stream, thereafter condensing the overhead stream to produce a liquid condensate containing substantially all of the entrained fines remaining in the stream, and removing substantially all of the fines from the condensate to produce a liquid oil product and wet solids, the improvement comprising recycling the wet solids into the second retorting zone whereby the condensate component of the wet solids is vaporized and removed and the fines component of the wet solids is dried.