A solvent is dispersed into a natural gas feed at a solvent injection point to produce a mixed feed. The mixed feed contains heavy components with a potentially fouling portion that can cause obstructions in a heat exchanger. A fluid injection system can inject the solvent intermittently, for instance, based on an amount of accumulation or expected accumulation of heavy component solids in the heat exchanger. The solvent prevents the potentially fouling portion of the heavy components from freezing, melts or dissolves the accumulation, and reduces the obstructions in the heat exchanger. The fluid injection system includes a solvent supply, an optional atomizer, an injection controller, optionally one or more sensors, and/or optionally a heater. The solvent injection system can disperse the solvent onto a flow surface for the natural gas feed and/or mixed feed to form a solvent film which further reduces heavy component solids.

A method and apparatus for producing liquefied natural gas. A pretreated natural gas stream is compressed in at least two serially arranged compressors to a pressure of at least 1,500 psia and cooled. The resultant cooled compressed natural gas stream is expanded in at least one work producing natural gas expander to a pressure less than 2,000 psia and no greater than the pressure to which natural gas stream has been compressed, thereby forming a chilled natural gas stream that is separated into a refrigerant stream and a non-refrigerant stream. The refrigerant stream is warmed in a heat exchanger through heat exchange with one or more process streams associated with pretreating the natural gas stream, thereby generating a warmed refrigerant stream. The warmed refrigerant stream and the non-refrigerant stream are then liquefied.

A system and method for liquefying a hydrogen gas feed stream uses a pre-cooling refrigerant for pre-cooling the feed stream, where the pre-cooling refrigerant is compressed, cooled and then separated to provide high pressure mixed refrigerant vapor and liquid streams. The high pressure vapor stream is cooled and directed to a cold vapor separator where cold separator liquid and vapor streams are formed. The cold separator vapor stream is cooled and expanded to provide a pre-cool refrigeration stream in a heat exchanger system. The high pressure pre-cooling refrigerant liquid and cold separator liquid streams are cooled and expanded and directed to the pre-cool refrigeration stream. A high pressure primary refrigerant steam, after compression and cooling, is further cooled in the heat exchanger system and then expanded using warm and cold expanders, with the resulting expanded primary refrigerant streams used to liquefy the pre-cooled hydrogen feed stream via heat exchange in the heat exchanger system.

A small to mid-scale liquefied natural gas production system and method is provided. The disclosed liquefied natural gas production system employs at least one heat exchanger, three turbine/expanders and at least three refrigerant compression stages. The expansion ratio of one turbine/expander is appreciably lower than the expansion ratio of the other turbine/expanders such that the temperature of the exhaust stream from the turbine/expander with the lower expansion ratio is above the critical point temperature of the compressed natural gas containing feed stream but colder than about −15° C. The present system and method may be configured using either a single nitrogen-based expansion refrigerant circuit or two separate refrigerant circuits wherein the turbine/expander with the lowest expansion ratio is contained within a separate refrigeration circuit from the other two turbine/expanders with the higher expansion ratios.

A cooling system includes a compressor configured to pressurize carbon dioxide to form pressurized carbon dioxide, a mixer configured to generate mixed refrigerant in which the pressurized carbon dioxide and solvent in a liquid state, a depressurization apparatus provided downstream from the mixer and configured to depressurize the mixed refrigerant, a separator configured to separate carbon dioxide in a gas state from the mixed refrigerant, a heat exchanger configured to exchange heat between the mixed refrigerant cooled through depressurization and a fluid to be cooled, and a second heat exchanger configured to cool the carbon dioxide or the mixed refrigerant using vaporized carbon dioxide or the mixed refrigerant.

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.

The invention relates to a liquefied gas storage facility, in particular for liquid hydrogen, comprising a liquefied gas tank intended to contain gas in liquid form and a gaseous phase, a device for cooling the contents of the tank, the cooling device comprising at least a first refrigerator with a cycle for refrigerating a cycle gas, said first refrigerator comprising, arranged in series in a cycle circuit: a member for compressing the cycle gas, a member for cooling the cycle gas, a member for expanding the second cycle gas and a member for reheating the expanded cycle gas, the cooling device comprising a first heat transfer fluid loop comprising a first end exchanging heat with a cold end of the first refrigerator and a second end comprising a first heat exchanger located in the tank, the first heat transfer fluid loop comprising a member for circulating the heat transfer fluid, characterized in that the first heat exchanger exchanges heat directly with the inside of the tank, that is to say that the first heat exchanger exchanges heat directly with the fluid which surrounds it in the tank.

A cooling system includes a compressor configured to pressurize carbon dioxide to form pressurized carbon dioxide, a mixer configured to generate mixed refrigerant in which the pressurized carbon dioxide and solvent in a liquid state, a depressurization apparatus provided downstream from the mixer and configured to depressurize the mixed refrigerant, a separator configured to separate carbon dioxide in a gas state from the mixed refrigerant, a heat exchanger configured to exchange heat between the mixed refrigerant cooled through depressurization and a fluid to be cooled, and a second heat exchanger configured to cool the carbon dioxide or the mixed refrigerant using vaporized carbon dioxide or the mixed refrigerant.

The invention relates to an integrated process and apparatus for liquefaction of natural gas and recovery of natural gas liquids. In particular, the improved process and apparatus reduces the energy consumption of a Liquefied Natural Gas (LNG) unit by using a portion of the already cooled overhead vapor from a fractionation column from an NGL (natural gas liquefaction) unit to, depending upon composition, provide, for example, reflux for fractionation in the NGL unit and/or a cold feed for the LNG unit, or by cooling, within the NGL unit, a residue gas originating from a fractionation column of the NGL unit and using the resultant cooled residue gas to, depending upon composition, provide, for example, reflux/feed for fractionation in the NGL and/or a cold feed for the LNG unit, thereby reducing the energy consumption of the LNG unit and rendering the process more energy-efficient.

A refrigerant circuit includes a first compression stage for compressing a mixed refrigerant gas, the first compression stage including at least a first compressor body and a second parallel compressor body, each compressor body including a suction inlet and an outlet, a first distribution means for splitting the flow of refrigerant gas to the first stage of compression across the at least two parallel compressor bodies, such that a first stream of refrigerant gas is fed to the suction inlet of the first compressor body and a second stream of refrigerant gas is fed to the suction inlet of the second compressor body, a second compression stage for compressing the mixed refrigerant gas, and a first merging means for recombining the first stream of refrigerant gas with the second stream of refrigerant gas downstream of the first compression stage for delivery to the second compression stage.