The present invention relates to a method of cooling and separating a hydrocarbon stream: (a) passing an hydrocarbon feed stream (7) through a first cooling and separation stage to provide a methane enriched vapour overhead stream (110) and a methane depleted liquid stream (10); (b) passing the methane depleted liquid stream (10) to a fractionation column (200) to obtain a bottom condensate stream (210), a top stream enriched in C1-C2 (220) and a midstream enriched in C3-C4 (230), (c) cooling the upper part of the fractionation column (201) by a condenser (206), (d) obtaining a split stream (112) from the methane enriched vapour overhead stream (110) and obtaining a cooled split stream (112) by expansion-cooling the split stream (112), (e) providing cooling duty to the top of the fractionation column (201) using the cooled split stream (112).

This invention relates to a system and method for liquefying natural gas. In another aspect, the invention concerns an improved liquefied natural gas facility employing a closed loop methane refrigeration cycle. In another aspect, the invention concerns the utilization of lean boil-off gas.

Hydrocarbon processing systems and a method for liquefied natural gas (LNG) production are described herein. The hydrocarbon processing system includes a fluorocarbon refrigeration system configured to cool a natural gas to produce LNG using a mixed fluorocarbon refrigerant and a nitrogen rejection unit (NRU) configured to remove nitrogen from the LNG.

A process and apparatus for liquefying natural gas includes a heavies recovery system. In another aspect, a liquefied natural gas (LNG) facility may employ an ethylene independent heavies recovery system. The recovery system may thus operate relying only on fluid input from upstream of an ethylene refrigeration cycle. A heavies-depleted stream recovered from a liquid withdrawn from a heavies removal column in the heavies recovery system may combine at a location downstream of the heavies removal column with an overhead withdrawn from the heavies removal column for further cooling of such combined stream into liquefied natural gas product.

Variable N2 content in feed gas ranging from 3 mol % to 50 mol % can be rejected from the process using a feed exchanger that is fluidly coupled with a cold separator and a single fractionation column to produce a nitrogen vent stream and streams that are suitable to be further processed for NGL recovery and LNG production.

An integrated method for the production of liquefied natural gas (LNG) and syngas is provided. The method can include the steps of: utilizing letdown energy of a high pressure natural gas stream that is withdrawn from a natural gas pipeline to provide a warm temperature cooling; utilizing a refrigeration cycle to provide a cold temperature cooling, wherein the refrigeration cycle comprises a refrigerant recycle compressor that is powered utilizing a steam turbine; and cooling a second high pressure natural gas stream using the warm temperature cooling and the cold temperature cooling to produce an LNG product stream. The second high pressure natural gas stream is withdrawn from the natural gas pipeline, and the steam turbine is powered by high pressure steam that is produced from a syngas production facility.

A mixed phase unstabilized hydrocarbon stream is created by partially evaporating an unstabilized hydrocarbon condensate stream, including indirectly heat exchanging the unstabilized hydrocarbon condensate stream against an effluent stream in a feed-effluent heat exchanger. The mixed phase unstabilized hydrocarbon stream is fed into a stabilizer column. A liquid phase of stabilized hydrocarbon condensate is discharged from a bottom end, while an overhead vapour stream consisting of a vapour phase comprising volatile components from the unstabilized hydrocarbon condensate stream is discharged from a top end of the stabilizer column. The overhead vapour stream is passed through an overhead condenser. The resulting partially condensed overhead stream is separated in an overhead separator into a vapour effluent stream and an overhead liquid stream. The effluent stream against which the unstabilized hydrocarbon condensate stream is heat exchanged in the feed-effluent heat exchanger comprises the vapour effluent stream.

A liquefaction process configured to facilitate thermal transfer in a heat exchanger during liquefaction of a natural gas feedstock. The liquefaction process can include compressing a process stream to a first pressure, the process stream comprising predominantly methane, cooling the process stream to a first temperature, expanding the process stream from the first pressure to a second pressure that is less than the first pressure, bleeding-off a first product from the process stream at the second pressure, and conditioning the first product for storage as liquid natural gas (LNG).

A mixed phase pressurized unstabilized hydrocarbon stream is fed into a stabilizer column at a feed pressure. A liquid phase of stabilized hydrocarbon condensate is discharged from a bottom end of the stabilizer column, while a vapour phase of volatile components from the pressurized unstabilized hydrocarbon condensate stream is discharged from a top end of the stabilizer column. The vapour phase being discharged from the top end of the stabilizer column is compressed and subsequently passed through an ambient heat exchanger wherein partial condensation takes place. The resulting partially condensed overhead stream is separated in an overhead separator into a vapour effluent stream and an overhead liquid stream. After discharging the overhead liquid stream from the overhead separator, it is selectively divided into a liquid reflux stream and a liquid effluent stream. The liquid reflux stream is expanded to the feed pressure and fed into the stabilizer column.

A liquefied natural gas (LNG) facility that employs a system to remove incondensable material from one or more refrigeration cycles within the facility. One or more embodiments of the present invention can be advantageously employed in an open-loop refrigeration cycle to remove at least a portion of one or more high vapor pressure components that have accumulated in the refrigerant cycle over time. In addition, several embodiments can be advantageously employed to stabilize facility operation in the event of drastic changes to the concentration of the natural gas feed stream introduced into the facility.