Air Products and Chemicals, Inc.

Howard C Rowles

Lee J Howard

Donald W Woodward

Dennis P Bernhard

Mark Julian Roberts

Christopher Francis Harris

Calvin L Ayres

Harvey L Vines

Miguel Rafael Alvarez

Gene A Lucadamo

Brian Alfred McNeil

Christopher Michael Ott

Jeffrey Alan Hopkins

Douglas L Bennett

Ruth Ann Davis

Glenn E Kinard

John Dollin Bassett

Thomas J Edwards

Kimberly Schroeder Grassi

Robert Newton Davis

Richard Alan Wright

Jacob M Geist

Randy James Nickel

Michael H Evans

Ramanathan R Tarakad

Daniel Lewis Longhurst

John A Pryor

Tsun-chiu Tsao

Arthur T Katsaros

Bruce Moodie Hill

Richard P Freeman

Robert L Teichman

Process for the recovery of components heavier than methane from natural gas, wherein the process comprises (a) cooling a natural gas feed to provide a cooled natural gas feed and introducing the cooled natural gas feed into an absorber column at a first location therein; (b) withdrawing from the absorber column a first overhead vapor stream depleted in components heavier than methane and a bottoms stream enriched in components heavier than methane; (c) introducing a methane-rich reflux stream at a second location in the absorber column above the first location; (d) separating the bottoms stream into a stream enriched in methane and one or more streams enriched in components heavier than ethane; and (e) introducing an absorber liquid comprising components heavier than ethane into the absorber column at a location between the first location and the second location.

Integrated high pressure NGL recovery in the production of liquefied natural gas

A method for the recovery of hydrogen and one or more hydrocarbons having one or more carbon atoms from a feed gas containing hydrogen and the one or more hydrocarbons, which process comprises cooling and partially condensing the feed gas to provide a partially condensed feed; separating the partially condensed feed to provide a first liquid stream enriched in the one or more hydrocarbons and a first vapor stream enriched in hydrogen; further cooling and partially condensing the first vapor stream to provide an intermediate two-phase stream; and separating the intermediate two-phase stream to yield a further-enriched hydrogen stream and a hydrogen-depleted residual hydrocarbon stream. Some or all of the cooling is provided by indirect heat exchange with cold gas refrigerant generated in a closed-loop gas expander refrigeration cycle.

Separation of hydrogen-hydrocarbon gas mixtures using closed-loop gas expander refrigeration

A method for cooling a process stream in which one of a plurality of open-loop refrigerant streams is cooled by indirect heat exchange with other of the open-loop refrigerant stream in a refrigerant heat exchanger to yield a cooled primary refrigerant stream. The process stream is cooled by indirect heat exchange with a process refrigerant stream in a separate process heat exchanger, wherein the process refrigerant stream comprises at least a portion of the cooled primary refrigerant stream. The method is particularly useful in large process plants which require multiple parallel heat exchangers to cool the process stream.

Method for providing refrigeration to parallel heat exchangers

Dephlegmator system without headers, collectors, or distributors at the bottom end of feed circuits in plate and fin exchangers operating in condensing or rectifying service. Each dephlegmator is installed within a pressure vessel, thereby eliminating the need for headers, collectors, or distributors at the bottom end of the feed circuits. In an alternative embodiment of the invention, upper and lower segments of the pressure vessel are isolated by a mid-vessel seal between the vessel and dephlegmator walls, and headers or collectors are not required at the upper and lower ends of the feed circuits.

Dephlegmator system and process

C,and C,hydrocarbons, particularly ethylene and propylene, are recovered from refinery or petrochemical plant gas mixtures by cooling and fractionating a feed gas mixture containing these hydrocarbons and lighter components. Refrigeration for the process is provided by a closed-loop gas expander refrigeration process cycle which preferably uses nitrogen as the recirculating refrigerant. Cooling and fractionation may be effected in a dephlegmator.

Nitrogen refrigerated process for the recovery of C2&plus; Hydrocarbons

A high purity methane product is recovered from a feed gas mixture containing methane and one or more hydrocarbons heavier than methane by cooling, condensing, and rectifying the feed in a dephlegmator. The high purity methane product, containing at least 98 mole % methane, can be liquefied and stored for use as a fuel for internal combustion engines. A hydrocarbon product containing components heavier than methane is also recovered. Methane recovery and C.sub.2.sup.+ hydrocarbon product purity can be improved by the use of a combined stripping heat exchanger and feed gas cooler. External refrigeration is utilized and can be supplemented in part by autorefrigeration provided by vaporizing dephlegmator liquid.

Production of refrigerated liquid methane

Nitrogen is removed from a pressurized feed gas mixture containing nitrogen and methane by cooling, partial condensation, and rectification in one or more dephlegmators. Autorefrigeration is provided by pressure letdown of selected process streams and external refrigeration is not required.

Dephlegmator process for nitrogen removal from natural gas

Hydrocarbons are recovered from the product purge gas in an alkene polymerization process by absorption of heavier hydrocarbons from the purge gas by an intermediate hydrocarbon stream to yield a vapor rich in inert gas and alkene monomer. Alkene monomer is condensed and rectified by dephlegmation at low temperatures from the inert gas, flashed and vaporized to provide refrigeration for the condensation step, and recycled to the polymerization process. The intermediate hydrocarbon from the absorption step is recycled to the polymerization process. Optionally a portion of the inert gas is reused for purge gas.

Recovery of hydrocarbons from polyalkene product purge gas

Olefins are recovered from thermally cracked gas or fluid catalytic cracking off gas by cooling the gas to condense a portion of the hydrocarbons, removing hydrogen from the noncondensed gas, and condensing the remaining hydrocarbons in a cold condensing zone using a dephlegmator which operates above about -166.degree. F. This mode of operation minimizes the amount of methane in the condensate which is further processed in demethanizer column(s) and permits the condensation of ethylene at warmer temperatures than possible using a partial condenser in the cold condensing zone. The use of a dephlegmator at temperatures above about -166.degree. F. minimizes or eliminates the formation and accumulation of unstable nitrogen compounds in the ethylene recovery system. Hydrogen is removed from the noncondensed gas in a process selected from polymeric membrane permeation, adsorptive membrane permeation, or pressure swing adsorption.

Olefin recovery from olefin-hydrogen mixtures

Light components are stripped from a multicomponent liquid feed mixture in a core type plate-fin heat exchanger by heating and partially vaporizing the mixture during downward flow in one of a plurality of multichannel flow passageways in the exchanger. The vapor thus formed flows upward and promotes vaporization of dissolved light components from the liquid to yield a liquid product substantially free of lighter components. The passageways are disposed in indirect heat exchange with one or more additional groups of passageways, and heat for partial vaporization of the downward-flowing liquid feed mixture is provided by indirect heat exchange with a condensing process stream. Alternatively, this heat is provided by a bottoms stream recovered from distillation of the stripped liquid product withdrawn from the core type plate-fin heat exchanger.

Light component stripping in plate-fin heat exchangers

Hydrocarbons are recovered from the product purge gas in an alkene polymerization process by absorption of heavier hydrocarbons from the purge gas by an intermediate hydrocarbon stream to yield a vapor rich in inert gas and alkene monomer. Alkene monomer is condensed at low temperatures from the inert gas, flashed and vaporized to provide refrigeration for the condensation step, and recycled to the polymerization process. The intermediate hydrocarbon from the absorption step is recycled to the polymerization process. Optionally a portion of the inert gas is reused for purge gas.

A closed-loop mixed refrigerant cycle provides efficient low-level refrigeration for recovering ethylene from a mixed gas feed. Compressed mixed refrigerant vapor is condensed at -20.degree. F. to -50.degree. F. and is subcooled to -175.degree. F. to -225.degree. F. by indirect heat exchange with cold H.sub.2, methane, and expander streams from elsewhere in the ethylene plant. A portion of the subcooled refrigerant may be flashed to provide additional subcooling of the main mixed refrigerant stream. Subcooled mixed refrigerant is subsequently flashed to provide very low temperature level refrigeration for feed condensation and demethanizer overhead condenser duties. The invention allows advantageous operation of the feed chilling train at pressures between 150 and 400 psia.

Mixed refrigerant cycle for ethylene recovery

Refrigeration is provided in an ethylene recovery plant by an open-loop mixed refrigeration cycle which utilizes components present in the ethylene-containing feed gas as the mixed refrigerant. Refrigeration is provided by subcooled mixed refrigerant at -175.degree. to -225.degree. F. for the demethanizer overhead condenser and for initial cooling and condensation of the ethylene-containing feed gas. Overall ethylene recoveries of up to 99.9% can be achieved at reduced power consumption compared with conventional ethylene recovery cycles. In addition, significant capital savings can be realized due to the simplification of equipment with the open-loop mixed refrigerant cycle, which can be operated advantageously at pressures between 150 and 400 psia.

Open loop mixed refrigerant cycle for ethylene recovery

A closed-loop mixed refrigerant cycle provides efficient low-level refrigeration for recovering ethylene from a mixed gas feed. Compressed mixed refrigerant vapor is condensed at -20.degree. F. to -50.degree. F. and is subcooled to -175.degree. F. to -225.degree. F. by indirect heat exchange with cold H.sub.2, methane, and expander streams from elsewhere in the ethylene plant. A portion of the subcooled refrigerant may be flashed to provide additional subcooling of the main mixed refrigerant stream. Subcooled mixed refrigerant is subsequently flashed to provide very low temperature level refrigeration for feed condensation and demethanizer overhead condenser duties.

Refrigeration is provided in an ethylene recovery plant by an open-loop mixed refrigeration cycle which utilizes components present in the ethylene-containing feed gas as the mixed refrigerant. Refrigeration is provided by subcooled mixed refrigerant at -175.degree. to -225.degree. F. for the demethanizer overhead condenser and for initial cooling and condensation of the ethylene-containing feed gas. Overall ethylene recoveries of up to 99.9% can be achieved at reduced power consumption compared with conventional ethylene recovery cycles. In addition, significant capital savings can be realized due to the simplification of equipment with the open-loop mixed refrigerant cycle.

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Center Valley, PA, United States of America

Howard C Rowles