The present disclosure relates to systems and methods that provide power generation using predominantly CO.sub.2 as a working fluid. In particular, the present disclosure provides for the use of a portion of the heat of compression from a CO.sub.2 compressor as the additive heating necessary to increase the overall efficiency of a power production system and method.

Natural gas liquefaction process in combination with a synthesis gas production process, where the steam derived from the synthesis gas production process is used as a heating source for the implementation of the pre-treatment step for eliminating the impurities liable to freeze during the natural gas liquefaction process.

Integration of a natural gas liquefaction system, a hydrogen production system, and power generation system to increase CO2 capture and improve overall plant efficiency. The predominantly methane endflash is sent to the hydrogen production system which produces hydrogen and CO2. The CO2 may be captured or beneficially used. At least a portion of the hydrogen produced is used to fuel gas turbines in the power generation which, in turn, provides power for the refrigeration compressor of the natural gas liquefaction system—either in the form of mechanical work or electricity.

Certain implementations of natural gas liquid fractionation plant waste heat conversion to simultaneous cooling capacity and potable water using Kalina Cycle and modified multi-effect distillation system can be implemented as a system. The system includes first waste heat recovery heat exchanger configured to heat a first buffer fluid stream by exchange with a first heat source in a natural gas liquid fractionation plant. The system includes a water desalination system comprising a first train of one or more desalination heat exchangers configured to heat saline by exchange with the heated first buffer fluid stream to generate fresh water and brine.

Certain aspects of natural gas liquid fractionation plant waste heat conversion to simultaneous power and cooling capacities using modified Goswami system can be implemented as a system. The system includes a waste heat recovery heat exchanger configured to heat a buffer fluid stream by exchange with a heat source in a natural gas liquid fractionation plant. The system includes a modified Goswami cycle energy conversion system including one or more first energy conversion system heat exchangers configured to heat a working fluid by exchange with the heated buffer fluid stream, a separator configured to receive the heated working fluid and to output a vapor stream of the working fluid and the liquid stream of the working fluid, a turbine and a generator, wherein the turbine and generator are configured to generate power by expansion of a first portion of the vapor stream of the working fluid, and a cooling subsystem including a cooling element configured to cool a process fluid stream from the natural gas liquid fractionation plant by exchange with a condensed second portion of the vapor stream of the working fluid.

Flowing a first buffer fluid and a second buffer fluid through a heat exchanger network thermally coupled to heat sources of a Natural Gas Liquid (NGL) fractionation plant, and transferring heat from the heat sources to the first buffer fluid and the second buffer fluid. Generating power via a first sub-system thermally coupled to the heat exchanger network and generating potable water from brackish water via a second sub-system thermally coupled to the heat exchanger network.

A method for exhaust waste energy recovery at the reciprocating gas engine-based polygeneration plant which includes supplying this plant with any on-site available methaneous gas, converting from 15 to 30% of supplied gas into electric or mechanical power and producing a liquefied methaneous gas (LMG) co-product from the other 85-70% of supplied gas, and thereby obviates a need for any specialized refrigeration equipment, refrigerants and fuel for LMG co-production at a rate of 0.4-0.6 ton/h for each MW of engine output and makes possible to increase the LMG co-production rate up to 0.9-1.1 t/MWh at the sacrifice of a fuel self-consumption minimized down to 1-2% of the amount of gas intended for liquefaction.

A method for exhaust waste energy recovery at the internal combustion engine polygeneration plant with the gas engine or gas turbine prime movers which includes supplying this plant with any on-site available methaneous gas (MG), converting from 20 to 30% of supplied MG into electric or mechanical power and producing a liquefied MG (LMG) co-product from the other 80-70% of supplied MG at a rate of 0.5-0.9 ton/h for each MW of engine output through converting and harnessing an engine exhaust as an effective refrigerant.

A system includes a waste heat recovery heat exchanger configured to heat a heating fluid stream by exchange with a heat source in a crude oil associated gas processing plant. The system includes an Organic Rankine cycle energy conversion system including a pump, an energy conversion heat exchanger configured to heat the working fluid by exchange with the heated heating fluid stream, a turbine and a generator configured to generate power by expansion of the heated working fluid, a cooling element configured to cool the expanded working fluid after power generation, and an accumulation tank. The heating fluid flows from the accumulation tank, through the waste heat recovery heat exchanger, through the Organic Rankine cycle energy conversion system, and back to the accumulation tank.

A method of recovering heat from a Natural Gas Liquid (NGL) fractionation plant for production of potable water. The method includes heating a buffer fluid via a heat exchanger in to transfer heat from the NGL fractionation plant to the buffer fluid. The method includes heating water with the buffer fluid discharged from the heat exchanger to produce potable water via train distillation effects.