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.

A method is proposed for compressing a gas in stages in a compressor arrangement (100, 200, 300, 400) having a plurality of compression stages (I-VI) which are connected together sequentially by a main line (1) and in which the gas, guided through the main line (1), is respectively compressed from a suction-side pressure level to a pressure-side pressure level and is heated by this compression from a suction-side temperature level to a pressure-side temperature level, wherein a feedback amount of the gas, guided through the main line (1), is at least temporarily removed from the main line (1) downstream of one of the compression stages (V), is fed to an expansion process, and is fed back into the main line (1) upstream of the same compression stage (V). It is provided that the pressure-side pressure level of the compression stage (V) downstream of which the feedback amount is removed from the main line (1) is a supercritical pressure level, that the feedback amount is expanded to a subcritical pressure level, that the feedback amount is fed to the expansion process at the pressure-side temperature level of the compression stage (V) downstream of which it is removed from the main line (1), and that the feedback amount is cooled only after being expanded and before and/or after being fed back into the main line (1). The invention also relates to a compressor arrangement (100, 200, 300, 400).

In a process for separating at least one heavy impurity such as hydrogen sulfide from crude carbon dioxide comprising significant quantities of at least one light impurity such as non-condensable gases, involving at least one heat pump cycle using carbon dioxide-containing fluid from the process as the working fluid, the light impurity is removed from the crude carbon dioxide and carbon dioxide is subsequently recovered from the removed light impurity, thereby improving overall carbon dioxide recovery and efficiency in terms of energy consumption.

A booster system includes: a cooling temperature regulating unit configured to regulate a temperature of an intermediate supercritical pressure liquid cooled and generated by a main cooling unit on upstream of a pump unit according to a flow rate of a supplied cooling medium; and a pressure detection unit configured to detect inlet pressure of the intermediate supercritical pressure liquid on an inlet side of the pump unit and detect outlet pressure of a target supercritical fluid on an outlet side of the pump unit. The cooling temperature regulating unit controls the flow rate of the cooling medium based on a pressure difference between the inlet pressure and the outlet pressure or a pressure ratio between the inlet pressure and the outlet pressure.

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 booster system for increasing pressure of an object gas includes: a first compression unit that compresses the object gas to intermediate pressure equal to or higher than the critical pressure and lower than the target pressure and generates an intermediate supercritical fluid; a cooling unit that cools the intermediate supercritical fluid with a cooling medium and generates an intermediate supercritical pressure liquid; a liquid extracting and pressure reducing unit that extracts a part of the intermediate supercritical pressure liquid; a flow regulating valve that regulates a flow rate of the extracted part of the intermediate supercritical pressure liquid; a second compression unit that increases pressure of the rest of the intermediate supercritical pressure liquid to be equal to or higher than the target pressure; and a pressure sensor that detects pressure of the intermediate supercritical pressure liquid.

An apparatus for separation of a flow containing at least 95 mol % of carbon dioxide and also at least one impurity lighter than carbon dioxide by distillation comprises a heat exchanger (20), a distillation column (30), expansion means (V3), means for sending the flow to be cooled in the heat exchanger, means for sending the cooled flow to be separated in the distillation column, means for withdrawing at the bottom of the column a liquid flow containing at least 99 mol % of carbon dioxide, means for sending at least a portion (12) of the liquid flow to be cooled in the heat exchanger to form a subcooled liquid (3), means for sending at least a portion of the subcooled liquid to the expansion means to produce a two-phase flow, a phase separator (40) for separating the two-phase flow to form a gas and a liquid, means for sending at least a portion (14) of the liquid from the phase separator to be vaporized in the heat exchanger and means for taking a portion (4) of the liquid from the phase separator.

A method for separating carbon dioxide from flue gas to generate a high purity CO2 stream.

A method is provided for separating off acid gases, in particular CO.sub.2 and H.sub.2S, from a hydrocarbon-rich fraction, in particular natural gas. The hydrocarbon-rich fraction is cooled and partially condensed. The resultant CO.sub.2-enriched liquid fraction is separated by rectification into a CO.sub.2-rich liquid fraction and a CO.sub.2-depleted gas fraction. The hydrocarbon-rich fraction is cooled close to the temperature of the CO.sub.2 triple point by means of a closed multistage refrigeration circuit. The refrigerant is a CO.sub.2 fraction of greater than 99.5% by volume. The rectification column is operated at a pressure between 40 and 65 bar. The reboiler of the rectification column is heated by means of a condensing refrigerant substream of the refrigeration circuit that is at a suitable pressure level.

According to certain embodiments of the invention, a gas containing at least 50% of carbon dioxide is cooled in a first exchanger so as to produce a cooled fluid, a liquid derived from the cooled fluid is sent to a distillation column to be separated therein, a head gas is withdrawn from the distillation column and reheated in the first exchanger, a vat liquid, which is richer in carbon dioxide than the gas containing at least 50% of carbon dioxide, is withdrawn and at least a portion thereof is heated in the first exchanger, at least a first portion of the vat liquid is vaporized in the first exchanger in order to produce a vaporized portion, the vaporized portion is sent back to the column and an NOx removal column is supplied with the liquefied cycle gas produced by vaporizing and reliquefying the vat liquid from the column.