The invention relates to a method for adjusting a cryogenic refrigeration apparatus including a plurality of liquefiers/refrigerators arranged in parallel in order to cool a single device. The method includes a step of calculating in real time the dynamic mean value of at least one operating parameter for all the liquefiers/refrigerators. The apparatus controlling in real time the at least one valve for controlling the stream of working gas of at least one liquefier/refrigerator in accordance with the difference between the instantaneous values of the parameter relative to said dynamic converge toward said dynamic mean value.

A method of cooling a boil-off gas (BOG) stream from a liquefied gas tank comprising at least the step of heat exchanging the BOG stream with a first refrigerant in a heat exchanger, the heat exchanger having an entry port and a warmer exit port, and comprising at least the steps of: (a) passing the first refrigerant into the entry port of the heat exchanger and into a first zone of the heat exchanger to exchange heat with the BOG stream, to provide a first warmer refrigerant stream; (b) withdrawing the first warmer refrigerant stream from the heat exchanger at an intermediate exit port between the entry port and the warmer exit port; (c) admixing the first warmer refrigerant stream with an oil-containing refrigerant stream to provide a combined refrigerant stream; (d) passing the combined refrigerant stream into the heat exchanger through an entry port located in a second zone of the heat exchanger that is warmer than the first zone; (e) passing the combined refrigerant stream out of the heat exchanger through the warmer exit port. The present invention is a modification of a refrigerant cycle for BOG cooling, and LNG re-liquefaction in particular, that allows the use of a cost-efficient oil-injected screw compressor in the refrigerant system. The present invention is also able to accommodate the possibility of different flows or flow rates of the first refrigerant stream and the oil-containing refrigerant stream, such that there is reduced or no concern by the user of the process in relation to possible oil freezing and clogging of the heat exchanger caused by variation of the flow or flow rate of the oil-containing refrigerant stream.

A method for large-scale offshore LNG production from natural gas gathered from an onshore gas pipe network is described. The natural gas is pre-treated on an onshore facility for removal of mercury, acid gas, water and C5+ hydrocarbons, and then compressed and piped to an offshore platform for further compression and cooling before being transferred to a floating liquefaction, storage and offloading vessel for liquefaction of the natural gas.

An LNG production plant is constructed from a plurality of containerised LNG liquefaction units. Each containerised LNG liquefaction unit can produce a predetermined quantity of LNG. For example, up to 0.3 MPTA. A manifold system enables connection between the plurality of containerised LNG liquefaction units, and at least a feed stream of natural gas, a source of electrical power, and an LNG storage facility. The production capacity of the plant is incrementally changed by connecting or disconnecting containerised LNG liquefaction units to or from the plant via the manifold system. Each unit contains its own liquefaction plant having a closed loop SMR circuit. Refrigerant within the SMR circuit is circulated solely by pressure differential generated by refrigerant compressors in the liquefaction plant.

A system for supplying compressed gas to several gas-fed devices is based on a liquid piston gas multistage compressor (100). Gas pressure measurements performed at a gas intake (10), an intermediate gas outlet (20) and at an end gas outlet (30) of the system allow controlling respective gas capacities of the compressor stages. Easy and reliable control can thus be obtained for the system operation. Varying the number of the compressor stages allows matching any pressure requirements for the gas delivery to all the gas-fed devices, and varying the gas capacities of the compressor stages allows easy adaptation to variable gas consumptions of the gas-fed devices.

A system for supplying compressed gas to several gas-fed devices is based on a liquid piston gas multistage compressor (100). Gas pressure measurements performed at a gas intake (10), an intermediate gas outlet (20) and at an end gas outlet (30) of the system allow controlling respective gas capacities of the compressor stages. Easy and reliable control can thus be obtained for the system operation. Varying the number of the compressor stages allows matching any pressure requirements for the gas delivery to all the gas-fed devices, and varying the gas capacities of the compressor stages allows easy adaptation to variable gas consumptions of the gas-fed devices.

A process and apparatus for utilization of an absorption chiller for hydrogen production can include an arrangement configured for providing at least one heated waste stream of fluid from at least one hydrogen production unit to an absorption chiller generator to power the absorption chiller. Coolant can be generated via the heated waste stream for feeding coolant from the generator to an evaporator for cooling a chilling medium to a pre-selected chilling temperature to provide cooling to one or more process elements. The warmed chilling medium can be returned to the absorption chiller evaporator for subsequent cooling back to the pre-selected chilling temperature to provide a closed-circuit cooling arrangement. The waste fluid fed to the generator can be output as a cooled waste fluid for returning to hydrogen production for further use or be output for treatment and/or disposal.

Method and installation for refrigerating the same application by means of several refrigerators/liquefiers disposed in parallel, the refrigerators/liquefiers in parallel using a working gas of the same nature having a low molar mass, that is to say having a mean total molar mass of less than 10 g/mol such as pure gaseous helium, each refrigerator/liquefier comprising a station for compressing the working gas, a cold box intended to cool the working gas at the output from the compression station, the working gas cooled by each of the respective cold boxes of the refrigerators/liquefiers being put in thermal exchange with the application with a view to supplying cold to the latter, in which a single compression station compresses the working gas for each of the respective separate cold boxes of the refrigerators/liquefiers disposed in parallel, the single compression station comprising only compression machines of the lubricated-screw type and systems for removing oil from the working fluid output from the compression machines, so that the compression machines and the oil-removal systems are shared by the refrigerators/liquefiers disposed in parallel.

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.

A refrigeration system for condensation of carbon dioxide (CO.sub.2) in a flue gas stream, the system includes a refrigeration circuit, a flue gas treatment system that includes a flue gas compressor, a flue gas adsorption drier, and a refrigeration system for condensation of CO.sub.2; and a method for condensation of CO.sub.2 in a flue gas stream using a circulating stream of an external refrigerant.