A carbon dioxide capturing apparatus using cold heat of liquefied natural gas (LNG) includes a heat exchanger to cool primary coolant using heat exchange between the primary coolant and the LNG; a chiller connected to the heat exchanger and configured to discharge capturing coolant colder than the primary coolant by performing a heat exchange between the capturing coolant and a cooling material; and a capturing cooler configured to capture carbon dioxide contained in flue gas by performing a heat exchange between the capturing coolant discharged from the chiller and the flue gas. A power generation system includes an LNG storage facility; a power generation facility discharging flue gas; a unit for heat exchange between the LNG and a coolant to regasify the LNG and cool the coolant; and a unit for capturing carbon dioxide contained in the flue gas by heat exchange between the discharged flue gas and the coolant.

In a purification method, a carbon dioxide-rich gas is cooled in a first brazed aluminum plate-fin heat exchanger, the cooled gas or at least one fluid derived from the cooled gas is sent to a purification step comprising a distillation step, the purification step produces a carbon dioxide-rich liquid which is cooled, then expanded, then sent to a second heat exchanger where it is heated by means of a fluid of the method, the exchanger carrying out an indirect heat exchange only between the carbon dioxide-rich liquid and the fluid of the method, the carbon dioxide-rich liquid at least partially vaporizes in the second exchanger and the vaporized gas formed heats up again in the first exchanger to form a carbon dioxide-rich gas.

In a method for separating a mixture containing carbon dioxide, the mixture is cooled in a heat exchanger and partially condensed and a first liquid is separated from the mixture in a first system operating at low temperature comprising at least one first phase separator and a gas from the first system is treated in a membrane system to produce a permeate and a non-permeate, the gas from the first system being divided into two portions, a first portion being sent to the membrane system without being heated and a second portion being heated to at least an intermediate temperature of the heat exchanger and then sent to the membrane system without being cooled.

A system captures carbon dioxide from a flue gas of a power generation facility by using cold heat of liquefied natural gas and utilizes the captured carbon dioxide for mining natural gas, using heat of the flue gas to regasify the LNG. Solidified dry ice is captured from gaseous carbon dioxide contained in the flue gas, and the captured dry ice is used as filler when mining natural gas. The system includes a mining facility, a vehicle to transport LNG liquefied by the mining facility; and a facility for regasifying the transported LNG and capturing dry ice from the carbon dioxide. In the regasification and capture facility, the flue gas exchanges heat with the LNG, thereby regasifying the LNG at an increased temperature and capturing the dry ice from the carbon dioxide. The captured dry ice is transported to the mining facility, which uses it for mining the natural gas.

A carbon dioxide-rich mixture is cooled in a first brazed aluminum plate-fin heat exchanger, at least one fluid derived from the cooled mixture is sent to a purification step having a distillation step and/or at least two successive partial condensation steps, the purification step produces a carbon dioxide-depleted gas which heats up again in the first exchanger, the purification step produces a carbon-dioxide rich liquid which is expanded, then sent to a second heat exchanger where it is heated by means of a fluid of the method, the exchanger carrying out an indirect heat exchange only between the carbon dioxide-rich liquid and the fluid of the method, the carbon dioxide-rich liquid at least partially vaporizes in the second exchanger and the vaporized gas formed heats up again in the first exchanger to form a carbon dioxide-rich gas which can be the end product of the method.

A method for separating a vapor from a carrier gas is disclosed. A hydrocyclone is provided with one or more nozzles on the wall of the hydrocyclone. A cryogenic liquid is provided to the tangential feed inlet at a velocity that induces a tangential flow and a cyclone vortex in the hydrocyclone. The carrier gas is injected into the hydrocyclone through the one or more nozzles. The vapor dissolves, condenses, desublimates, or a combination thereof, forming a vapor-depleted carrier gas and a vapor-enriched cryogenic liquid. The vapor-depleted gas is drawn through the vortex finder while the vapor-enriched cryogenic liquid is drawn through the apex nozzle outlet. In this manner, the vapor is removed from the carrier gas.

A process and device for separating a vapor from a gas is disclosed. A direct-contact exchanger comprising a droplet-generating apparatus in a top portion of the exchanger and a bubbling apparatus in a bottom portion of the exchanger is provided. An inlet gas, comprising a vapor, is passed through the bubbling apparatus, forming bubbles in a bottoms liquid. The bottoms liquid strips a portion of the vapor and exchanges heat with the bubbles, producing a product liquid and a middle gas. A barren liquid is passed through the droplet-generating apparatus to form droplets of the barren liquid in the top portion. The droplets descend against the middle gas and strip a second portion of the vapor from and exchange heat with the middle gas, producing the bottoms liquid, which collects in the bottom portion, and a product gas.

A device for recovering carbon dioxide and nitrogen from flue gas includes a pretreatment system, a CO.sub.2and N.sub.2separation system, a N.sub.2purification and liquefaction system, and a CO.sub.2 purification and liquefaction system. The pretreatment system includes a high-temperature NG cooler, a gas-liquid separator, a booster fan, and a dryer; the CO.sub.2and N.sub.2 separation system includes a low-temperature LNG cooler and a cryogenic adsorption device; the N.sub.2 purification and liquefaction system includes a set of N.sub.2 distillation and liquefaction device consisting of a compressor, a cooler, a heat exchanger, a gas-liquid separator, and a distillation tower; and the CO.sub.2purification and liquefaction system includes a set of CO.sub.2 distillation and liquefaction device consisting of a compressor, a cooler, a condenser, an evaporator, a liquefier, and a purification tower, which are used for further purifying and liquefying desorbed gas obtained from the CO.sub.2and N.sub.2 separation system.

Processes for separating CO from CO.sub.2 in flue gas streams from partial oxidation regenerator in FCC processes, as well as reducing the sulfur content of the flue gas stream are described. The processes involve separating the cooled reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream. The processes may incorporate either dry sorbent injection (DSI) units or wet gas scrubbing units to remove sulfur compounds. The separation processes can utilize cryogenic fractionation, pressure swing adsorption (PSA) processes including vacuum PSA, and temperature swing adsorption (TSA) processes. The flue gas stream can be used to preheat the CO.sub.2 recycle stream.

A liquefied natural gas production plant comprising a carbon capture unit wherein the refrigerant fluid thermodynamic refrigeration cycle of the carbon capture system and the refrigerant fluid thermodynamic refrigeration cycle of the liquefied natural gas production plant are integrated by using the same refrigerant fluid and sharing at least some apparatuses, thus reducing the overall number of apparatuses and in particular the overall number of compressors and consequently reducing the emissions of carbon dioxide produced by the compressors.