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.

A system and method for removing nitrogen and producing a high pressure methane product stream from natural gas feed streams having wide variations in nitrogen and methane content are disclosed. Optional add-on systems may be incorporated into the nitrogen and methane separation to produce an NGL sales stream to reduce excess hydrocarbons in the nitrogen vent stream, or to recover helium. The system and method of the invention are particularly suitable for use with feed streams in excess of 50 MMSCFD and up to 300 MMSCFD and containing up to 100 ppm carbon dioxide. Typical power requirements for compressing the methane product stream to produce a suitably high pressure stream for sale are reduced according to the systems and methods of the invention.

A method for producing a plate heat exchanger with at least two heat exchanger blocks which are produced separately from one another in a soldering furnace Each heat exchanger block has multiple separating sheets arranged parallel to one another and which form a plurality of beat exchanger passages for fluids involved in a heat exchange process. At least one support provided with solder is heated in order to melt the solder, the support is arranged between opposing outer surfaces of the heat exchanger blocks to be connected which are placed one on top of the other or adjacently, the support(s) thus being fixed between the opposing outer surfaces. After the solder is hardened, a bonded and heat-conductive connection is produced between the heat exchanger blocks. Sheets or wire arrangement can be used as the supports.

Methods and systems for recovering alkenes (e.g. ethylene, propylene) from process gas streams, including multi-step condensing of the process gas stream, are provided herein.

A process for separating the components of a gas mixture comprising methane, nitrogen, and at least one hydrocarbon having at least two carbon atoms, or a mixture of these hydrocarbons, including the following steps: a) introduction of a stream of the mixture to be treated into a demethanization of the gas mixture with at least N demethenization column; b) partial condensation of a gas mixture, comprising less than 1 mol % of hydrocarbons having at least two carbon atoms, extracted from the demethanization unit to obtain a liquid, at least a portion of which is treated in order to be extracted as denitrogenated natural gas and a second gas, c) introduction of the second gas into a nitrogen removal unit having N nitrogen removal columns.

An apparatus and method for flow management and CO.sub.2-recovery from a CO.sub.2 containing hydrocarbon flow stream, such as a post CO.sub.2-stimulation flowback stream. The apparatus including a flow control zone, a gas separation zone, a pretreatment zone, and a CO.sub.2-capture zone. The CO.sub.2-capture zone is in fluid communication with the pretreatment zone to provide CO.sub.2-capture from a pretreated flowback gas stream and output a captured CO.sub.2-flow stream. The CO.sub.2-capture zone includes a flow splitter to direct a first portion of the pretreated flowback gas stream to a CO.sub.2-enricher to provide an enriched CO.sub.2-stream for mixing with a second portion of the pretreated flowback gas to form a mixed stream. The CO.sub.2-capture zone further includes at least one condenser to output the captured CO.sub.2-flow stream.

A system and method for removing nitrogen and producing a high pressure methane product stream from natural gas feed streams having wide variations in nitrogen and methane content are disclosed. Optional add-on systems may be incorporated into the nitrogen and methane separation to produce an NGL sales stream to reduce excess hydrocarbons in the nitrogen vent stream, or to recover helium. The system and method of the invention are particularly suitable for use with feed streams in excess of 50 MMSCFD and up to 300 MMSCFD and containing up to 100 ppm carbon dioxide. Typical power requirements for compressing the methane product stream to produce a suitably high pressure stream for sale are reduced according to the systems and methods of the invention.

A system and method for removing nitrogen and producing a high pressure methane product stream from natural gas feed streams having wide variations in nitrogen and methane content are disclosed. Optional add-on systems may be incorporated into the nitrogen and methane separation to produce an NGL sales stream to reduce excess hydrocarbons in the nitrogen vent stream, or to recover helium. The system and method of the invention are particularly suitable for use with feed streams in excess of 50 MMSCFD and up to 300 MMSCFD and containing up to 100 ppm carbon dioxide. Typical power requirements for compressing the methane product stream to produce a suitably high pressure stream for sale are reduced according to the systems and methods of the invention.

An apparatus and method for flow management and CO.sub.2-recovery from a CO.sub.2 containing hydrocarbon flow stream, such as a post CO.sub.2-stimulation flowback stream. The apparatus including a flow control zone, a gas separation zone, a pretreatment zone, and a CO.sub.2-capture zone. The CO.sub.2-capture zone is in fluid communication with the pretreatment zone to provide CO.sub.2-capture from a pretreated flowback gas stream and output a captured CO.sub.2-flow stream. The CO.sub.2-capture zone includes a flow splitter to direct a first portion of the pretreated flowback gas stream to a CO.sub.2-enricher to provide an enriched CO.sub.2-stream for mixing with a second portion of the pretreated flowback gas to form a mixed stream. The CO.sub.2-capture zone further includes at least one condenser to output the captured CO.sub.2-flow stream.

A method of designing, constructing, and operating a hydrocarbon gas treatment plant is disclosed. A target hydrocarbon production range for a hydrocarbon gas meeting a required product specification is established. A cryogenic distillation column is designed and constructed with a vapor capacity to meet the target hydrocarbon production range. A variable feed refrigeration system is incorporated to cool an inlet feed of the hydrocarbon gas. The variable feed refrigeration system is designed to handle the target hydrocarbon production range and a wide range of contaminant concentrations in the inlet feed. A variable bottoms heating system is incorporated to handle heating duties associated with the wide range of contaminant concentrations in the inlet feed. A variable bottoms pumping system is incorporated to handle liquid flows associated with the wide range of contaminant concentrations in the inlet feed.