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 proposed system comprises a supply line for at least one engine, on which line is situated a first compression unit (3) for said gas and a bypass to a return line on which are successively situated cooling means (10) and reliquefaction means (30). The cooling means successively comprise a second compression unit (11, 12, 13) and a heat exchanger (17). Downstream of the second compression unit (11, 12, 13) a bypass to a loop (18, 20, 21) comprises first expansion means (14), the loop rejoining the return line upstream of the second compression unit (11, 12, 13) after having passed through the heat exchanger (17) in the opposite direction with respect to the gas fraction not bypassed via the loop.

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.

The present disclosure relates to systems and methods that provide a low pressure liquid CO.sub.2 stream. In particular, the present disclosure provides systems and methods wherein a high pressure CO.sub.2 stream, such as a recycle CO.sub.2 stream from a power production process using predominately CO.sub.2 as a working fluid, can be divided such that a portion thereof can be expanded and used as a cooling stream in a heat exchanger to cool the remaining portion of the high pressure CO.sub.2 stream, which can then be expanded to form a low pressure CO.sub.2 stream, which may be in a mixed form with CO.sub.2 vapor. The systems and methods can be utilized to provide net CO.sub.2 from combustion in a liquid form that is easily transportable.

A proposed method provides a highly efficient fueled power output augmentation of the liquid air energy storage (LAES) with zero carbon emissions of its exhaust. It combines the production of liquid air using excessive power from the renewable or/and conventional energy sources and an effective recovery of stored air for production of on-demand power in the fueled supercharged reciprocating internal combustion engine (ICE) and associated expanders. A mutually beneficial integration between the LAES and ICE makes possible to recover the ICE exhaust energy for increase in power produced by the LAES expanders and to use a cold thermal energy of air re-gasified at the LAES facility for cryogenic capture of CO.sub.2 emissions from the ICE exhaust.

Disclosed herein is a boil-off gas reliquefaction apparatus. The boil-off gas reliquefaction apparatus includes: a plurality of compressors arranged in parallel to compress boil-off gas discharged from a storage tank; a reliquefaction unit reliquefying the boil-off gas compressed by each of the plurality of compressors; and a plurality of supply lines providing a path through which the boil-off gas is supplied from the plurality of compressors to the reliquefaction unit and a path through which the boil-off gas flows in the reliquefaction unit, wherein the plurality of supply lines is arranged independently of one another without being joined together.

A boil-off gas recovery system 1 includes a tank 2 storing liquefied gas, an oil supply type compressor 3b for compressing boil-off gas generated by partial evaporation of the liquefied gas in the tank 2, and a reliquefying system 9 for liquefying the boil-off gas compressed by the oil supply type compressor 3b and returning the liquefied gas that has been liquefied to the tank 2. The reliquefying system 9 includes a heat exchanger for oil constituent condensation 11 for cooling down the boil-off gas to a temperature equal to or lower than a condensation temperature of an oil constituent contained in the boil-off gas, a separator 14 for separating the oil constituent condensed by the heat exchanger for oil constituent condensation 11 from the boil-off gas, and a reliquefying portion for liquefying the boil-off gas from which the oil constituent is separated.

Disclosed is a method of discharging lubricant oil from a BOG reliquefaction system configured to reliquefy BOG by compressing the BOG by a compressor, cooling the compressed BOG through heat exchange with non-compressed BOG by a heat exchanger, and reducing a pressure of fluid cooled through heat exchange by a pressure reducer. In the lubricant oil discharge method, the compressor comprises at least one oil-lubrication type cylinder and it is determined that it is time to discharge condensed or solidified lubricant oil, if at least one of preset conditions is satisfied.

Disclosed herein is a BOG reliquefaction system for LNG vessels. The BOG reliquefaction system includes a compressor compressing BOG, a heat exchanger cooling the compressed BOG by exchanging heat between the compressed BOG and BOG used as a refrigerant, and an expansion unit for expanding the BOG having been cooled by the heat exchanger, wherein the heat exchanger includes a core, in which heat exchange between a hot fluid and a cold fluid occurs, the core including a plurality of diffusion blocks, and a fluid diffusion member diffusing a fluid introduced into the core or a fluid discharged from the core.