Exxonmobil Upstream Research Company

E Lawrence Kimble

Ronald R Bowen

Moses Minta

James Ronald Rigby

Jaime A Valencia

Scott D Kelman

Bruce T Kelley

John B Stone

Ransdall K Smith

Lonny R Kelley

Richard B Harley

H Gary Winningham

Robert E Steele

Daniel J Hawrysz

A method and a system for feeding a feed gas including methane (CH) and carbon dioxide (CO) to a cryogenic distillation column are provided herein. The method includes flowing a freeze zone COvapor stream into a freezing section of the column to produce an overhead stream that exits the column. The method includes heating the overhead stream via a heating component to reduce or prevent solidification of the COin the overhead stream.

Heating component to reduce solidification in a cryogenic distillation system

A system and method for an intermediate pressure vessel to receive a purge in a cryogenic distillation column system. The vessel operates at an intermediate pressure to reduce solidification of the purge. The cryogenic distillation column receives a natural gas having methane and acid gas. The column discharges an overhead stream rich in the methane, and a bottoms stream rich in the acid gas. An overhead system receives the overhead stream, and discharges a vapor methane product, and a cooled liquid for reflux to the cryogenic distillation column.

Purge to intermediate pressure in cryogenic distillation

Offshore facilities and methods are provided to enable the mooring of a ship carrying a liquefied gas to an offshore structure with one or more decks upon which are located (i) regasification facilities; (ii) single point mooring means for mooring a ship that is carrying a liquefied gas; (iii) means for offloading said liquefied gas into said regasification facilities; and (iv) means for transferring gas from said regasification facilities to a gas transport pipeline.

Single point mooring regasification tower

This invention is a method and apparatus for production of pressurized liquefied gas. First, a gas stream is cooled and expanded to liquefy the gas stream. The liquefied gas stream is then withdrawn as pressurized gas product and a portion is recycled through the heat exchanger to provide at least part of the cooling and is returned to the stream. Recycling the pressurized liquefied gas product helps keep the cooling and compression of the gas stream in the supercritcal region of the phase diagram. J-T valves in parallel with the expander permits running the system until the stream is in the supercritical region of its phase diagram and the hydraulic expander can operate. This process is suitable for natural gas streams containing methane to form a pressurized liquefied natural gas (PLNG) product.

Process for producing a pressurized liquefied gas product by cooling and expansion of a gas stream in the supercritical state

A process is provided for converting a boil-off stream comprising methane to a liquid having a preselected bubble point temperature. The boil-off stream is pressurized, then cooled, and then expanded to further cool and at least partially liquefy the boil-off stream. The preselected bubble point temperature of the resulting pressurized liquid is obtained by performing at least one of the following steps: before, during, or after the process of liquefying the boil-off stream, removing from the boil-off stream a predetermined amount of one or more components, such as nitrogen, having a vapor pressure greater than the vapor pressure of methane, and before, during, or after the process of liquefying the boil-off stream, adding to the boil-off stream one or more additives having a molecular weight heavier than the molecular weight of methane and having a vapor pressure less than the vapor pressure of methane.

Reliquefaction of boil-off from liquefied natural gas

The invention is an absorption process for recovering C components from a pressurized liquid mixture comprising C and C . The pressurized liquid mixture is at least partially vaporized by heating the liquid mixture in a heat transfer means. The heat transfer means provides refrigeration to an absorption medium that is used in treating the vaporized mixture in an absorption zone. The vaporized mixture is passed to an absorption zone that produces a first stream enriched in C and a second stream enriched in C components. The pressurized liquid mixture is preferably pressurized liquid natural gas (PLNG) having an initial pressure above about 1,724 kPa (250 psia) and an initial temperature above &minus;112&deg; C. (&minus;170&deg; F.). Before being vaporized, the pressurized liquid mixture is preferably boosted in pressure to approximately the desired operating pressure of the absorption zone.

Process for recovering ethane and heavier hydrocarbons from methane-rich pressurized liquid mixture

Systems and methods are provided for delivering pressurized liquefied natural gas to an import terminal equipped with containers and vaporization facilities suitable for conventional LNG.

Unloading pressurized liquefied natural gas into standard liquefied natural gas storage facilities

A process is disclosed for producing a displacement gas to be used in displacing a pressurized liquefied gas from one or more containers. A portion of the liquefied gas to be displaced is further pressurized and it is then separated into a first fraction and a second fraction. The first fraction is expanded by a suitable expansion means, and the expanded fraction is passed to a separation means to produce a liquid stream and a gas stream. The second fraction is heated to covert it to a vaporous product stream. A portion of the vaporous product stream is withdrawn, expanded, and passed to the separation means. A gas stream produced by the separation means is expanded, and it is then available for use as a displacement gas for displacing liquefied gas from one or more containers.

Process for producing a displacement gas to unload pressurized liquefied gas from containers

A process is disclosed for liquefying natural gas to produce a pressurized liquid product having a temperature above &minus;112&deg; C. using two mixed refrigerants in two closed cycles, a low-level refrigerant to cool and liquefy the natural gas and a high-level refrigerant to cool the low-level refrigerant. After being used to liquefy the natural gas, the low-level refrigerant is (a) warmed by heat exchange in countercurrent relationship with another stream of the low-level refrigerant and by heat exchange against a first stream of the high-level refrigerant, (b) compressed to an elevated pressure, and (c) aftercooled against an external cooling fluid. The low-level refrigerant is then cooled by heat exchange against a second stream of the high-level mixed refrigerant and by exchange against the low-level refrigerant. The high-level refrigerant is warmed by the heat exchange with the low-level refrigerant, compressed to an elevated pressure, and aftercooled against an external cooling fluid.

Dual multi-component refrigeration cycles for liquefaction of natural gas

Process components, containers, and pipes are provided that are constructed from ultra-high strength, low alloy steels containing less than 9 wt % nickel and having tensile strengths greater than 830 MPa (120 ksi) and DBTTs lower than about &minus;73&deg; C. (&minus;100&deg; F.).

Process components, containers, and pipes suitable for containing and transporting cryogenic temperature fluids

A process is disclosed for conveying gas stream rich in methane, such as natural gas. In the first step of the process, gas is supplied to a pipeline at an entry pressure that is substantially higher than the output pressure of the pipeline. The drop in pressure in the pipeline causes a lowering of the gas temperature, preferably to a temperature below about &minus;29&deg; C. (&minus;20&deg; F.). The entry pressure of the gas to the pipeline is controlled to achieve a predetermined output pressure of the gas from the pipeline. Output gas from the pipeline is then liquefied to produce liquefied gas having a temperature above about &minus;112&deg; C. (&minus;170&deg; F.) and a pressure sufficient for the liquid to be at or below its bubble point temperature. The pressurized liquefied gas is then further transported in a suitable container.

Refrigeration process for liquefaction of natural gas

A process is disclosed for reliquefying boil-off gas produced by pressurized liquid natural gas. In this process, refrigeration duty is provided to a heat exchanger by means of a refrigeration cycle. Pressurized natural gas is cooled by the heat exchanger and then expanded to a lower pressure to produce a liquid stream that is passed to a first phase separator. A boil-off vapor is passed through the heat exchanger and it is then compressed and cooled before being recycled back through the heat exchanger. The compressed, cooled boil-off gas is then expanded and passed to a second phase separator. A vapor stream produced by the second separator is removed from the process. A liquid stream produced by the second phase separator is passed to the first phase separator to produce a pressurized liquid having a temperature above about &minus;112&deg; C. and a pressure sufficient for the liquid to be at or below its bubble point.

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Sugar Land, TX, United States of America

E Lawrence Kimble