Certain aspects of natural gas liquid fractionation plant waste heat conversion to simultaneous power, cooling and potable water using integrated mono-refrigerant triple cycle and modified MED system can be implemented as a system that includes two heating fluid circuits thermally coupled to multiple heat sources of a NGL fractionation plant. An integrated triple cycle system, which includes an organic Rankine cycle (ORC), a refrigeration cycle and an ejector refrigeration cycle, is thermally coupled to the first heating fluid circuit. A MED system, configured to produce potable water, thermally coupled to the second heating fluid circuit. The system includes a control system configured to actuate control valves to selectively thermally couple the heating fluid circuits to portions of the heat sources of the NGL fractionation plant.

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 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 a natural gas liquid fractionation plant waste heat conversion to power using Organic Rankine Cycle can be implemented as a system. The system includes a heating fluid circuit thermally coupled to multiple heat sources of a natural gas liquid (NGL) fractionation plant. The system includes a power generation system that includes an organic Rankine cycle (ORC), which includes (i) a working fluid that is thermally coupled to the heating fluid circuit to heat the working fluid, and (ii) an expander configured to generate electrical power from the heated working fluid. The system includes a control system configured to actuate a set of control valves to selectively thermally couple the heating fluid circuit to at least a portion of the multiple heat sources of the NGL fractionation plant.

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.

A method for recovering natural gas liquids from a recycle stream having natural gas liquids includes receiving a carbon dioxide recycle stream that comprises carbon dioxide, natural gas, and the natural gas liquids. The carbon dioxide recycle stream is separated into a purified carbon dioxide recycle stream and a natural gas liquids stream. The purified carbon dioxide recycle stream comprises the carbon dioxide and the natural gas, and the natural gas liquids stream comprises the natural gas liquids. In another embodiment, a system comprises piping and a separator. The piping is configured to receive a recycle stream, and the separator is coupled to the piping and is configured to separate the recycle stream into a purified recycle stream and a natural gas liquids stream.

One or more specific embodiments disclosed herein includes a method for separating hydrogen from an olefin hydrocarbon rich compressed effluent vapor stream, employing a single heat exchanger, multiple gas-liquid separators, multiple expander/compressor sets, and a rectifier attached to a liquid product drum.

Certain aspects of a natural gas liquid fractionation plant waste heat conversion to power using dual turbines Organic Rankine Cycle can be implemented as a first heating fluid circuit thermally coupled to first multiple heat sources of a natural gas liquid (NGL) fractionation plant, a second heating fluid circuit thermally coupled to second multiple heat sources of the NGL fractionation plant, and two power generation systems, each including an organic Rankine cycle (ORC). A control system actuates a first set of control valves to selectively thermally couple the first heating fluid circuit to at least a portion of the first multiple heat sources of the NGL fractionation plant, and to actuate a second set of control valves to selectively thermally couple the second heating fluid circuit to at least a portion of the second multiple heat sources of the NGL fractionation plant.

An overhead recycle process apparatus (100) comprises a heat exchange arrangement (116, 118, 120, 146, 150, 198) and a separator (110) in fluid communication with an absorber (104) and a de-ethaniser (106), the absorber (104) having a reflux inlet port (164). An ethane rectifier (170) in fluid communication with the de-ethaniser (106) is also provided, the de-ethaniser (106) being arranged to provide cooling by heat exchange to an overhead stream path (194) of the ethane rectifier (170). The ethane rectifier (170) comprises a reflux drum (182) having an ethane outlet port (184) and a vapour phase outlet port (185) in fluid communication with the reflux inlet port (164) of the absorber (104).

A system for removing freezing components from a feed gas includes a heavy hydrocarbon removal heat exchanger and a scrub device. The scrub device includes a scrub column that receives a cooled feed gas stream from the heat exchanger and a reflux separation device. Vapor from the scrub column is directed to the heat exchanger and cooled to create a reflux stream that includes a liquid component. This reflux stream is directed to the reflux separation device and a resulting liquid component stream is used to reflux the column. Vapor from the reflux separation device is expanded and directed to the heat exchanger, where it provides refrigeration, and a processed feed gas line.