A thermally integrated separation method, including exchanging heat indirectly between an inlet stream and a liquid carbon dioxide/NGL containing stream in a heat exchanger, thereby producing a cold inlet stream and a vaporized carbon dioxide/NGL containing stream, introducing the cold inlet stream into a cryogenic separation unit, thereby producing the liquid carbon dioxide/NGL containing stream and a methane-rich stream, introducing the methane-rich stream into a membrane separation unit, thereby producing a methane rich product stream, and a permeate stream, and introducing the vaporized carbon dioxide/NGL containing stream into a carbon dioxide/NGL separation unit, thereby producing a carbon dioxide rich product stream and a NGL rich product stream. Wherein, at least a portion of the liquid carbon dioxide/NGL containing stream bypasses the heat exchanger and is introduced into the carbon dioxide/NGL separation unit in liquid phase.

Carbon dioxide is recovered from an exhaust gas in the form of liquid carbon dioxide or supercritical carbon dioxide utilizing a rotary separator. Nitrogen gas recovered from the rotary separator can be expanded to provide cooling for carbon dioxide in a closed-loop CO2 power cycle that is used to cool the exhaust gas upstream of the rotary separator. The recovery can power itself and can produce excess electricity from waste heat.

This method comprises passing a residual stream into a flash drum to form a gaseous overhead flow and liquid bottom flow, and feeding the bottom flow into a distillation column, It comprises cooling the overhead flow in a heat exchanger to form a cooled overhead flow. It comprises the extraction of a gaseous overhead stream at the head of the distillation column, and the formation of at least one effluent stream from the overhead stream and/or from the top stream. The separation of the cooled overhead flow comprises passing the cooled overhead flow into an absorber, and injecting a methane-rich stream into the absorber to place the cooled overhead flow in contact with the methane-rich 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 integrated heat exchanger, multiple gas-liquid separators, external refrigeration systems, and a rectifier attached to a liquid product drum.

A method for vaporizing liquid propane to be supplied as a raw material to a naphtha cracking ractor. The method comprises: decompressing liquid propane to lower a vaporization point and vaporize at least a portion of the liquid propane; utilizing vaporization heat, generated during vaporization of the portion of liquid propane, as a refrigerant; compressing the vaporized propane gas to increase pressure of the propane gas and produce compressed propane gas; and preheating the compressed propane gas. By using this method, it is possible to reduce pressure of liquid propane to a significantly lower pressure than the related art method so that all the vaporization latent heat or vaporization heat included in liquid propane may be utilized as a refrigerant, while also reducing heat energy consumed in a preheat process before it is supplied to the naphtha cracking reactor.

A process and apparatus reboil a propylene splitter bottoms by heat exchange and/or a deethanizer bottoms stream with a compressed propylene splitter overhead stream. Use of single splitter compressor and operation of the propane-propylene splitter column at lower pressure are enabled, whereas conventionally two splitter compressors and higher splitter pressure were necessary to provide a propylene product stream and a propane recycle stream of equivalent quality.

Systems and processes for detecting leaks into a refrigeration system having a heat exchanger where the process side is configured to operate at a higher pressure than the refrigerant side. The system includes a refrigerant circulation system including a refrigerant feed pipe fluidly connected to and configured to provide a refrigerant to an inlet of the refrigerant side of the heat exchanger, as well as a refrigerant effluent pipe fluidly connected to and configured to receive a refrigerant from an outlet of the refrigerant side of the heat exchanger. One or more sensors are provided, the sensors being configured to measure a property of the refrigerant, such as temperature, pressure, or flow rate, for example. Additionally, the system for detecting leaks includes a digital control system configured to provide an alert when a signal from at least one of the one or more sensors is indicative of a leak from the process side of the heat exchanger to the refrigerant side of the heat exchanger.

A gas recovery system for a compressor, said gas recovery system being equipped with: a distillation column that brings a supply gas in a liquid state into contact with a mixed gas, thereby cooling and liquefying a process gas in the mixed gas, and heating and gasifying the liquid supply gas; a process gas recovery line that is connected to the lower part of the distillation column and recovers the liquid process gas discharged from the distillation column; and a supply gas recovery line that is connected to the upper part of the distillation column and recovers the gaseous supply gas discharged from the distillation column.

A refrigeration system for use in petrochemical plants, such as an ethylene production plant includes a refrigerant vent rectifier. The rectifier purifies the refrigerant by removing low molecular weight inerts. The refrigeration system is more efficient, consumes less energy and increases plant capacity.

Disclosed herein are processes for producing and separating ethane and ethylene. In some embodiments, an oxidative coupling of methane (OCM) product gas comprising ethane and ethylene is introduced to a separation unit comprising two separators. Within the separation unit, the OCM product gas is separated to provide a C.sub.2-rich effluent, a methane-rich effluent, and a nitrogen-rich effluent. Advantageously, in some embodiments the separation is achieved with little or no external refrigeration requirement.