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) passing the first warmer refrigerant stream through an entry port located in a second zone of the heat exchanger that is warmer than the first zone (d) passing an oil-containing refrigerant stream through an entry port located in a second zone of the heat exchanger that is warmer than the first zone; (e) mixing the first warmer refrigerant stream and the oil-containing stream in the heat-exchanger to form a combined refrigerant stream; and (f) passing the combined refrigerant stream out of the heat exchanger through the warmer exit port.

The present invention corresponds to a gas cooling and condensing system using fluid energy and comprising a gas feed line, a first vortex tube connected to the gas feed line, a second vortex tube connected to the first vortex tube and a first heat exchanger connected to the second vortex tube and to the gas feed line. Said gas cooling and condensing system is a modular system, which may be replicated and connected in series or in parallel to another modular system to obtain a cooler or higher mass flow gas than that obtained with a single modular system.

Moreover, the system of the present invention is optionally connected to thermal recovery, pressure recovery, recirculation or venting elements for the utilization of the waste gas streams. Furthermore, the system of the present invention does not require additional energy to that obtained from the pressure of the feed line for obtaining liquefied gas. On the other hand, the system of the present invention taps the pressure drop required between the compressed gas transport and distribution activities.

A heat exchanger having a plurality of heat exchange bodies, each heat exchange body having a first inlet configured to receive a first fluid, a first outlet configured to discharge a second fluid, a first distribution means for the first fluid, which is connected to the first inlets of the heat exchange bodies, the first distribution means having at least one main distribution duct, a first discharging means for the second fluid, which is connected to the first outlets of the heat exchange bodies, the first discharging means comprising at least one main discharging duct. The plurality of heat exchange bodies may have a first set of heat exchange bodies mounted in parallel and a second set of heat exchange bodies mounted in parallel.

A dual-mode LNG liquefier arrangement that is configurable to operate in a first mode broadly characterized as a low pressure, liquid nitrogen add LNG liquefier without turbo-expansion or a second mode broadly characterized as a low pressure, liquid nitrogen add LNG liquefier with turbo-expansion.

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.

The invention relates to a method of using an indirect heat exchanger comprising a plurality of heat exchange modules arranged in a rectangular grid. Each heat exchange module comprises a plurality of first and second fluid flow channels extending in a first and second direction. The indirect heat exchanger comprises first and second manifolds fluidly connecting the first and second fluid flow channels of one heat exchange module with the first and second fluid flow channels of adjacent heat exchange modules thereby forming one or more first fluid paths. The invention also relates to a facility for processing liquefied natural gas including at least one indirect heat exchanger as described above.

A heat exchanger system includes a core-in-shell heat exchanger and a liquid/gas separator. The liquid/gas separator is configured to receive a liquid/gas mixture and to separate the gas from the liquid. The liquid/gas separator is connected to the core-in-shell heat exchanger via a first line for transmitting gas from the liquid/gas separator to a first region in the core-in-shell heat exchanger and connected to the core-in-shell heat exchanger via a second line for transmitting liquid from the liquid/gas separator to a second region of the core-in-shell heat exchanger

Systems and methods are provided for the production of liquefied natural gas. At least one of the systems may include a plurality of compression assemblies in fluid communication with a precooler assembly. One compression assembly may be a part of a precooling loop and may include at least one compressor driven by a variable or fixed speed motor. Another compression assembly may be part of a liquefaction loop and may include at least one pair of compressors, each compressor driven by a respective turbine. The liquefaction loop may be fluidly coupled to a main heat exchanger utilized to liquefy at least a portion of a feed gas stream containing natural gas flowing through the main heat exchanger, thereby producing liquefied natural gas.

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.

An LNG production system including a boil off gas recondenser that can recondense boil off gas without using a BOG compressor and without depending on an LNG liquefaction process is provided.