A method for separating a gas mixture comprising carbon monoxide, nitrogen and hydrogen involves sending a hydrogen-depleted fluid to a denitrification column (K2) having a top condenser (C1) and a bottom reboiler (R2) in order to produce a nitrogen-enriched gas at the top of the column and a nitrogen-depleted liquid at the bottom of the column, cooling the condenser of the denitrification column by means of a nitrogen cycle using a nitrogen compressor (V1, V2, V3), vaporising, in the heat exchanger of the condenser, the liquid nitrogen (53) from the nitrogen cycle, and returning the nitrogen (55) vaporised in the heat exchanger to the nitrogen compressor.

A process for removing a foulant from a gas stream. The gas stream is cooled in a series of heat exchangers, causing a portion of the foulant to desublimate and become entrained in a cryogenic liquid. This foulant slurry stream is pressurized, cooled, and separated into a pressurized foulant solid stream and the cryogenic liquid stream. The pressurized foulant solid stream is melted to produce a liquid foulant stream. Heat exchange processes, both internal and external, are provided that close the heat balance of the process. In this manner, the foulant is removed from the gas stream.

Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprising cooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. A flash gas separated from the liquefied natural gas is warmed and combined with the natural gas feed stream.

Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.

A system for liquefying production gas from a gas source containing a fluid having C1-C12 entrained gases includes a first phase separator for separating the C1-C12 gases from the fluid from the gas source. The first phase separator has an inlet in fluid communication with the gas source, a gas outlet and at least one alternative outlet. A first cryogenic liquefaction vessel has an inlet and an outlet. The inlet is in fluid communication with the gas outlet of the first phase separator. The first cryogenic liquefaction vessel cools the C1-C12 gases to liquefy the C3-C12 petroleum gases. A second phase separator is provided for separating the C3-C12 liquefied gases from the C1-C2 gases. The second phase separator has an inlet, a liquid outlet and a gas outlet. The inlet is in fluid communication with the outlet of the first cryogenic liquefaction vessel. At least one storage vessel is provided in fluid communication with the liquid outlet of the second phase separator for collection of the liquefied C3-C12 petroleum gases.

Certain aspects of natural gas liquid fractionation plant waste heat conversion to simultaneous power, cooling and potable water using integrated mono-refrigerant triple cycle and modified MED system can be implemented as a system that includes two heating fluid circuits thermally coupled to multiple heat sources of a NGL fractionation plant. An integrated triple cycle system, which includes an organic Rankine cycle (ORC), a refrigeration cycle and an ejector refrigeration cycle, is thermally coupled to the first heating fluid circuit. A MED system, configured to produce potable water, thermally coupled to the second heating fluid circuit. The system includes a control system configured to actuate control valves to selectively thermally couple the heating fluid circuits to portions of the heat sources of the NGL fractionation plant.

A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.

A system for liquefying production gas from a gas source containing a fluid having C1-C12 entrained gases includes a first phase separator for separating the C1-C12 gases from the fluid from the gas source. The first phase separator has an inlet in fluid communication with the gas source, a gas outlet and at least one alternative outlet. A first cryogenic liquefaction vessel has an inlet and an outlet. The inlet is in fluid communication with the gas outlet of the first phase separator. The first cryogenic liquefaction vessel cools the C1-C12 gases to liquefy the C3-C12 petroleum gases. A second phase separator is provided for separating the C3-C12 liquefied gases from the C1-C2 gases. The second phase separator has an inlet, a liquid outlet and a gas outlet. The inlet is in fluid communication with the outlet of the first cryogenic liquefaction vessel. At least one storage vessel is provided in fluid communication with the liquid outlet of the second phase separator for collection of the liquefied C3-C12 petroleum gases.

Certain aspects of natural gas liquid fractionation plant waste heat conversion to simultaneous power, cooling and potable water using integrated mono-refrigerant triple cycle and modified MED system can be implemented as a system that includes two heating fluid circuits thermally coupled to multiple heat sources of a NGL fractionation plant. An integrated triple cycle system, which includes an organic Rankine cycle (ORC), a refrigeration cycle and an ejector refrigeration cycle, is thermally coupled to the first heating fluid circuit. A MED system, configured to produce potable water, thermally coupled to the second heating fluid circuit. The system includes a control system configured to actuate control valves to selectively thermally couple the heating fluid circuits to portions of the heat sources of the NGL fractionation plant.

A system includes a waste heat recovery heat exchanger configured to heat a heating fluid stream by exchange with a heat source in a crude oil associated gas processing plant. The system includes a modified Goswami cycle energy conversion system including a first group of heat exchangers configured to heat a first portion of a working fluid by exchange with the heated heating fluid stream and a second group of heat exchangers configured to heat a second portion of the working fluid. The modified Goswami cycle energy conversion system includes a separator configured to receive the heated first and second portions of the working fluid and to output a vapor stream of the working fluid and a liquid stream of the working fluid; a first turbine and a generator are configured to generate power by expansion of a first portion of the vapor stream of the working fluid; a cooling subsystem including one or more cooling elements configured to cool a chilling fluid stream by exchange with a cooled second portion of the vapor stream of the working fluid; and a second turbine configured to generate power from the liquid stream of the working fluid.