Claims
- 1. In a hydrodesulfurization process for removing sulfur from liquid hydrocarbons by reacting the sulfur in the liquid hydrocarbons with hydrogen to form H2S, separating from the liquid hydrocarbons a sour hydrogen gas stream consisting of unreacted hydrogen, H2S, and undesired light hydrocarbons; removing H2S to sweeten the said hydrogen stream, separating at least some of the undesired light hydrocarbons; and thereupon recycling the hydrogen stream for further reaction in the process;
the improvement enabling efficient separation of the light hydrocarbons without substantial loss of recyclable hydrogen, comprising:
(a) separating both the H2S and said light hydrocarbons from said sour hydrogen gas stream by passing the stream through an absorber where it is reacted with a liquor comprising a nonaqueous solvent containing dissolved sulfur, a base consisting essentially of a tertiary amine having sufficient strength and concentration to drive the reaction between H2S sorbed by said liquor and said dissolved sulfur to form a nonvolatile polysulfide which is soluble in the sorbing liquor, and a solubilizing agent for maintaining the solubility of polysulfide intermediates which may otherwise separate during the said process; said light hydrocarbons being absorbed in said liquor; (b) separating the light hydrocarbons from the sorbing liquor from step (a); (c) converting the dissolved nonvolatile polysulfide in said sorbing liquor to sulfur which remains dissolved in said liquor by contacting the liquor with an oxidizing agent; (d) converting at least part of said dissolved sulfur in the liquor to solid particulate sulfur at a point downstream of the absorber; and (e) separating said solid sulfur from the liquor.
- 2. A process in accordance with claim 1, wherein the light hydrocarbons absorbed in said liquor are separated by passing the liquor from step (a) to a flash vessel and flashing the light hydrocarbons from the liquor
- 3. A process in accordance with claim 1 wherein SO2 is used as the said oxidizing gas.
- 4. A process in accordance with claim 1 wherein the sour hydrogen gas stream is at a pressure of at least 2000 psig.
- 5. A process in accordance with claim 2, wherein a stream of sorbing liquor from the flash vessel is recirculated to the absorber to absorb further light hydrocarbons.
- 6. A process in accordance with claim 1, wherein the temperature in said absorber is at least 10 degrees F. higher than the gaseous sour hydrogen inlet stream to the absorber.
- 7. A process in accordance with claim 1 wherein said nonaqueous solvent is selected from the group consisting of alkyl-substituted naphthalenes, diaryl alkanes, phenyl-o-xylylethane, phenyl tolyl ethanes, phenyl naphthyl ethanes, phenyl aryl alkanes, dibenzyl ether, diphenyl ether, partially hydrogenated terphenyls, partially hydrogenated diphenyl ethanes, partially hydrogenated naphthalenes, and mixtures thereof.
- 8. A process in accordance with claim 7, wherein said base is selected from the group consisting of N,N dimethyloctylamine, N,N dimethyldecylamine, N,N dimethyldodecylamine, N,N dimethyltetradecylamine, N,N dimethylhexadecylamine, N-methyldicyclohexylamine, tri-n-butylamine, tetrabutylhexamethylenediamine, N-ethylpiperidine hexyl ether, 1-piperidineethanol, N-methyldiethanolamine, 2-(dibutylamino)ethanol, and mixtures thereof.
- 9. A process in accordance with claim 8 wherein said solubilizing agent is selected from one or more members of the group consisting of alkylarylpolyether alcohol, benzyl alcohol, phenethyl alcohol, 1-phenoxy-2-propanol, 2-phenoxyethanol, tri(propylene glycol) butyl ether, tri(propylene glycol) methyl ether, di(ethylene glycol) methyl ether, tri(ethylene glycol) dimethyl ether and benzhydrol.
- 10. A process in accordance with claim 8, wherein said solubilizing agent is selected from one or more polar organic compounds selected from the group consisting of sulfolane, propylene carbonate, and tributyl phosphate.
- 11. In a hydrodesulfurization system for removing sulfur from liquid hydrocarbons, and including reactor means for reacting the sulfur in the liquid hydrocarbons with hydrogen to form H2S; separator means for separating from the reacted liquid hydrocarbons a sour hydrogen gas stream consisting of unreacted hydrogen, H2S, and undesired light hydrocarbons; absorber means for contacting the sour hydrogen stream with a scrubbing composition, for removing H2S from the said sour hydrogen stream to sweeten the said hydrogen stream; means for separating at least some of the undesired light hydrocarbons from said sweetened hydrogen stream; and means for recycling the hydrogen stream to said reactor for further reaction;
the improvement enabling efficient separation of the light hydrocarbons without substantial loss of recyclable hydrogen, comprising:
said absorber means for removing H2S to sweeten the said hydrogen stream being the same said means which separated at last some of the undesired light hydrocarbons.
- 12. A system in accordance with claim 11, wherein said absorber means which separates both the H2S and said light hydrocarbons from said sour hydrogen gas stream, contacts the stream with a liquor comprising a nonaqueous solvent containing dissolved sulfur, a base consisting essentially of a tertiary amine having sufficient strength and concentration to drive the reaction between H2S sorbed by said liquor and said dissolved sulfur to form a nonvolatile polysulfide which is soluble in the sorbing liquor, and a solubilizing agent for maintaining the solubility of polysulfide intermediates which may otherwise separate during the said process; said light hydrocarbons being absorbed in said liquor; and
means for separating the light hydrocarbons from the sorbing liquor exiting said absorber; means for converting the dissolved nonvolatile polysulfide in said sorbing liquor to sulfur which remains dissolved in said liquor by contacting the liquor with an oxidizing agent; means for converting at least part of said dissolved sulfur in the liquor to solid particulate sulfur at a point downstream of the absorber; and means for separating said solid sulfur from the liquor.
- 13. A system in accordance with claim 12, wherein said means for separating said light hydrogens, includes a flash vessel for receiving the spent scrubbing liquor from said absorber means, and flashing the light hydrocarbons from the liquor
- 14. A system in accordance with claim 12, further including means for introducing SO2 into said system as the said oxidizing gas.
- 15. A system in accordance with claim 14, further including means for recirculating a stream of sorbing liquor from said flash vessel to said absorber to absorb further light hydrocarbons and H2S.
RELATED APPLICATION
[0001] This application claims priority from U.S. Provisional Application Serial No. 60/314,197, filed Aug. 22, 2001.
Provisional Applications (1)
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Number |
Date |
Country |
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60314197 |
Aug 2001 |
US |