The present invention provides a method to separate CO2 from a contaminated hydrocarbon-containing stream. The method comprises obtaining a multiphase contaminated hydrocarbon-containing stream (100) containing at least a vapour phase, a liquid phase and a solid phase, creating a slurry stream (120) from the multiphase stream. The slurry stream is fed to a crystallization chamber comprising CO2 seed particles. A liquid hydrocarbon stream (170) is obtained from the crystallization chamber (91) and a concentrated slurry (140) is obtained. The concentrated slurry (140) is removed from the crystallization chamber (91) by means of an extruder (142), thereby obtaining solid CO2. A feedback stream (141) is obtained from the solid CO2 comprising CO2 seed particles having an average size greater than 100 micron. The feedback stream (141) is passed into the crystallization chamber (91).

The subject matter disclosed herein relates to a liquefaction system. Specifically, the present disclosure relates to systems and methods for condensing a pressurized gaseous working fluid, such as natural gas, using at least one turboexpander in combination with other cooling devices and techniques. In one embodiment, a turboexpander may be used in combination with a heat exchanger using vapor compression refrigeration to condense natural gas.

A system for liquefying a gas includes a liquefaction heat exchanger having a feed gas inlet adapted to receive a feed gas and a liquefied gas outlet through which the liquefied gas exits after the gas is liquefied in the liquefying passage of the heat exchanger by heat exchange with a primary refrigeration passage. A mixed refrigerant compressor system is configured to provide refrigerant to the primary refrigeration passage. An expander separator is in communication with the liquefied gas outlet of the liquefaction heat exchanger, and a cold gas line is in fluid communication with the expander separator. A cold recovery heat exchanger receives cold vapor from the cold gas line and liquid refrigerant from the mixed refrigerant compressor system so that the refrigerant is cooled using the cold vapor.

Provided is a partial reliquefaction system including a boil-off gas (BOG) compression system receiving a BOG exiting from a liquefied natural gas (LNG) storage tank, a high-pressure compression section receiving a BOG stream from the BOG compression system, a heat exchanger effectuating a temperature drop of the BOG stream, an expander receiving the cooled BOG stream after passing through the heat exchanger, and a separator vessel for receiving a gas/liquid mixture, wherein a gas portion of the gas/liquid mixture is recirculated through the heat exchanger to act as the cooling medium for the heat exchanger.

A method of producing liquefied natural gas (LNG) is disclosed. A natural gas is compressed in at least two serially arranged compressors to a pressure of at least 2,000 psia and cooled to form a cooled compressed natural gas stream. The cooled compressed natural gas stream is additionally cooled to a temperature below an ambient temperature to form an additionally cooled compressed natural gas stream, which is expanded in at least one work producing natural gas expander to a pressure that is less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream. The chilled natural gas stream is liquefied by indirect heat exchange with a refrigerant to form liquefied natural gas and a warm refrigerant. The cooled compressed natural gas stream is additionally cooled using the warm refrigerant.

Described herein are systems and processes to produce liquefied natural gas (LNG) using liquefied nitrogen (LIN) as the refrigerant. Greenhouse gas contaminants are removed from the LIN using a greenhouse gas removal unit. The LNG is compressed prior to being cooled by the LIN.

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).

A system and method for cryogenic purification of a hydrogen, nitrogen, methane and argon containing feed stream to produce a methane free, hydrogen and nitrogen containing synthesis gas and a methane rich fuel gas, as well as to recover an argon product stream, excess hydrogen, and excess nitrogen is provided. The disclosed system and method are particularly useful as an integrated cryogenic purifier in an ammonia synthesis process in an ammonia plant. The excess nitrogen is a nitrogen stream substantially free of methane and hydrogen that can be used in other parts of the plant, recovered as a gaseous nitrogen product and/or liquefied to produce a liquid nitrogen product.

A process for liquefying methane-rich gases comprising providing a stream of feed methane-rich gas at a pressure of from 40 bar to 120 bar and containing higher hydrocarbons; providing a stream of methane-rich recycle gas at a pressure of from 40 bar to 120 bar; mixing the feed gas with a first part of the recycle gas; passing the resulting mixture to a gas expander, the expander outlet having a pressure of between 3 bar and 50 bar, so as to form a mixture of vapor and a condensed liquid containing higher hydrocarbons; separating the expander outlet stream into a liquid stream and a vapor stream; reheating and compressing said vapor stream to a pressure of from 40 bar to 120 bar to form a first constituent of the above-said recycle gas; cooling a second part of the said recycle gas to a temperature higher than the outlet temperature of the said expander; passing said cooled second part of the recycle gas into a liquefaction unit to form liquefied methane and a second vapor stream; reheating and compressing said second vapor stream to a pressure of from 40 bar to 120 bar to form a second constituent of the above-said recycle gas.

Systems and a method for the formation of a liquefied natural gas (LNG) are disclosed herein. The system includes a first fluorocarbon refrigeration system configured to chill a natural gas using a first fluorocarbon refrigerant and a second fluorocarbon refrigeration system configured to further chill the natural gas using a second fluorocarbon refrigerant. The system also includes a nitrogen refrigeration system configured to cool the natural gas using a nitrogen refrigerant to produce LNG and a nitrogen rejection unit configured to remove nitrogen from the LNG. As an alternative embodiment, the nitrogen refrigeration system can be replaced by a methane autorefrigeration system.