Yuv Raj Mehra

US Patent:

48835153, Nov 28, 1989

Filed:

Sep 29, 1987

Appl. No.:

7/102350

Inventors:

Yuv R. Mehra - The Woodlands TX
Freylon B. Coffey - Austin TX

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX

International Classification:

F25J 300

US Classification:

62 17

Abstract:

A continuous process is disclosed for separating components of a hydrocarbon gas stream which are selected from the group consisting of methane, ethane, higher saturated hydrocarbons, and mixtures thereof by countercurrently contacting the hydrocarbon gas stream with a physical solvent selected from the group consisting of: (1) paraffinic solvents having molecular weights ranging from 75 to 140 and UOP characterization factors ranging from 12. 0 to 13. 5, these factors being independent of the aromatic content of the paraffinic solvents, (2) naphthenic solvents having molecular weights ranging from 75 to 130 and UOP characterization factors ranging from 10. 5 to 12. 0, these factors being independent of the aromatic content of the naphthenic solvents, and (3) benzene and toluene, to produce an overhead stream which is rich in methane and a rich solvent bottoms stream and then recovering the lean physical solvent and a C. sub. 2 + hydrocarbons product from the rich solvent bottoms stream and recycling the recovered solvent stream to the contacting step.

US Patent:

48835145, Nov 28, 1989

Filed:

Jul 16, 1987

Appl. No.:

7/074226

Inventors:

Yuv R. Mehra - The Woodlands TX

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX

International Classification:

F25J 300

US Classification:

62 17

Abstract:

A process is described for processing an inert-rich natural gas stream with a lean oil physical solvent to obtain a specification-grade inert gas product, and a specification-grade hydrocarbon gas product, preferably in combination with an existing absorber plant. The process is an adaptation of the extractive flashing and extractive stripping versions of the Mehra Process.

US Patent:

52243508, Jul 6, 1993

Filed:

May 11, 1992

Appl. No.:

7/881250

Inventors:

Yuv R. Mehra - The Woodlands TX

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX

International Classification:

F25J 300

US Classification:

62 17

Abstract:

A subquality nitrogen-rich natural gas stream containing more than 0. 1 mol % helium is countercurrently extracted with a lean physical solvent to produce a rich solvent bottoms stream which is flashed twice to produce a methane-rich gas product and a nitrogen-helium product which is fed to at least one membrane unit. A reject nitrogen stream and a crude helium stream are discharged from this unit. The crude helium stream is either compressed to a pressure within the range of 200 to 3,000 psia for sale or is compressed to no more than 1,000 psia and fed to a PSA unit which produces a reject nitrogen stream and a highly purified (99. 99+ mol %) helium stream which is compressed to a pressure within the range of 200 to 3,000 psia for sale.

US Patent:

56819080, Oct 28, 1997

Filed:

Jan 25, 1996

Appl. No.:

8/591314

Inventors:

Yuv R. Mehra - The Woodlands TX
Robert H. Stodghill - Houston TX

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX

International Classification:

C08F 234

US Classification:

526 68

Abstract:

A process for rejecting reactor byproduct from the polymerization reactor in an olefins polymerization process wherein reactor waste gas stream(s) comprising unreacted monomers, reactor byproduct and light components are treated in an absorption process to additionally recover the monomers. The absorption process comprises contacting the reactor waste gas stream(s) with an absorption solvent in an absorption zone to produce a gas stream comprising the light components, and a liquid stream comprising the absorption solvent, absorbed reactor byproduct and absorbed monomers. The liquid stream is fractionated in a distillation column to produce a distillation column bottoms stream that is the absorption solvent which is conveyed to the absorption zone, and an overhead stream comprising the monomers and reactor byproduct which is further fractionated in a splitter column to reject the reactor byproduct as a bottoms stream. The recovered monomers from the splitter overhead can be conveyed to the reactor. In a preferred embodiment, the absorption solvent consists essentially of components derived from the reactor waste gas stream(s) so that no external solvent is required.

US Patent:

56875843, Nov 18, 1997

Filed:

Aug 30, 1996

Appl. No.:

8/697829

Inventors:

Yuv R. Mehra - The Woodlands TX

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX

International Classification:

F25J 300

US Classification:

62632

Abstract:

A retro fitted unit to an existing simple refrigerated natural gas plant that substantially increases the amounts of propane, butanes and natural gasoline, or ethane, propane, butanes and natural gasoline recovered from the natural gas in the existing gas treatment plant, wherein in one embodiment the existing natural gas treatment plant includes a refrigerated feed cooler, a separator and a stabilizer and the retrofitted unit comprises an NGL absorber, a refrigerated lean solvent cooler and a lean solvent regenerator; and wherein in a second embodiment the existing simple refrigerated gas treatment plant additionally includes an NGL fractionation train that separates the recovered NGL into saleable fractions and wherein the NGL fractionation train includes a debutanizer that produces all or part of the lean solvent utilized in the retrofitted unit which comprises an NGL absorber and a refrigerated solvent cooler; and wherein the natural gas treatment process utilizes a solvent that is pre-saturated with lighter undesirable components present in the overhead stream from the NGL absorber.

US Patent:

55519725, Sep 3, 1996

Filed:

Aug 23, 1995

Appl. No.:

8/518145

Inventors:

Glenn C. Wood - Houston TX
Yuv R. Mehra - The Woodlands TX

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX

International Classification:

B01D 4714

US Classification:

95192

Abstract:

An absorption process for separating a feed gas stream having components with a spectrum of volatilities including volatile (light) components, intermediate volatility components, and least volatile (heavy) components. The disclosed process includes the steps of: (1) contacting the feed gas stream with an internally generated liquid lean solvent stream in an absorber to produce a light product gas stream that is composed of predominantly light components and a rich solvent stream containing most of the intermediate and heavy components; (2) flashing the rich solvent stream at reduced pressure in a flash zone to produce an intermediate product gas stream composed predominantly of intermediate components and a lean solvent stream; (3) conveying the lean solvent stream from the flashing zone to the absorber, wherein the lean solvent is composed predominantly of heavy components supplied from the feed; the process does not use an external lean solvent. The process is particularly useful for rejecting nitrogen from natural gas and for recovering hydrogen from refinery and petrochemical process offgases.

US Patent:

55212646, May 28, 1996

Filed:

Aug 3, 1995

Appl. No.:

8/398349

Inventors:

Yuv R. Mehra - The Woodlands TX
Robert H. Stodghill - Houston TX

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX

International Classification:

C08F 234

US Classification:

526 68

Abstract:

A process for gas phase polymerization of olefins wherein reactor vent gas stream(s) comprising unreacted monomers and light components are treated in an absorption process to recover the monomers. The absorption process comprises contacting the reactor vent gas stream(s) with an absorption solvent in an absorption zone to produce a gas stream comprising the light components, and a liquid stream comprising the absorption solvent and absorbed monomers. The liquid stream is fractionated in a distillation column to produce a distillation column bottoms stream that is the absorption solvent which is conveyed to the absorption zone, and an overhead stream comprising the monomers which can be conveyed to the reactor. In a preferred embodiment, the absorption solvent consists essentially of components derived from the reactor vent gas stream(s) so that no external solvent is required.

US Patent:

52200973, Jun 15, 1993

Filed:

Feb 19, 1992

Appl. No.:

7/836911

Inventors:

Wilfred K. Lam - Arcadia CA
Yuv R. Mehra - The Woodlands TX
Don W. Mullins - Glendora CA

Assignee:

Advanced Extraction Technologies, Inc. - Houston TX
Kinetic Technology International Corp. - San Dimas CA

International Classification:

C07C 700
C07C 710
C07C 503
F25J 302

US Classification:

585809

Abstract:

A continuous process is described for contacting an olefins-containing feed gas stream, freed of CO. sub. 2 and sulfur compounds, in a front-end heat-pumped depropanizer to remove the C. sub. 4+ compounds, selectively hydrogenating the overhead stream to significantly reduce the acetylene and diolefins content, dehydrating the reactor effluent to remove traces of moisture, feeding the dehydrated stream to an intercooled and reboiled demethanizing absorber to produce a rich solvent containing ethylene and heavier hydrocarbons, feeding the absorber overhead stream to an auto refrigerated recovery unit to remove hydrogen, methane, and CO as overhead to a fuel gas system, separating the rich solvent in a solvent regenerator into an overhead stream of ethylene and heavier hydrocarbons and a bottom lean solvent stream for recycle to the demethanizing absorber, combining the overhead of the solvent regenerator with the bottoms of the demethanizer in the auto refrigerated recovery unit, and feeding the combined stream to a deethanizer which produces an overhead stream that is split into ethylene as product and ethane for recycling to the cracker.