In a method for cooling a flow containing at least 35% carbon dioxide and at least 0.2 ?g/Nm.sup.3 of mercury, the mercury being in liquid and/or gas form, the flow is cooled in a first brazed aluminum plate-fin heat exchanger from a first temperature to a second temperature higher than ?38.6? C. to form a cold flow at the second temperature, and the flow cooled to the second temperature is cooled in a second heat exchanger, which is a tube and shell heat exchanger, to a third temperature lower than ?38.6? C.

Exhaust gas from which impurities have been removed through pressurization and cooling by a compressor-based impurity separation mechanism is further cooled by a refrigerator-type heat exchanger. Drain produced from the cooling by the refrigerator-type heat exchanger is discharged and supplied as an alkalinity control agent to at least upstream of an aftercooler in a first impurity separator.

A system and method for power generation and CO.sub.2 sequestration include a fuel cell system configured to generate power using natural gas (NG), a container configured to store liquid natural gas (LNG), and a fluid processor configured to convert LNG received from the container into NG and to convert exhaust output from the fuel cell system to dry ice by transferring heat between and the LNG and the exhaust.

In a process for the separation of a stream containing carbon dioxide, water and at least one light impurity including a separation step at subambient temperature, the feed stream is compressed in a compressor comprising at least two stages to form a compressed feed stream, the compressed feed stream is purified in an adsorption unit to remove water and form a dried compressed stream, the dried compressed stream or a stream derived therefrom is cooled to a subambient temperature and separated by partial condensation and/or distillation in a separation apparatus, liquid enriched in carbon dioxide is removed from the separation apparatus, the adsorption unit is regenerated using a regeneration gas and the regeneration gas is formed by separating, by permeation in a permeation unit, the dried compressed stream or a gas derived therefrom, the permeate of the permeation unit constituting the regeneration gas.

Provided are a supply apparatus and a supply method for supplying fluid carbon dioxide that are energy-saving and efficient. The supply apparatus for supplying fluid carbon dioxide includes: a circulation system including a purifying unit that removes impurities and contaminants from the carbon dioxide, a storage unit that includes a condenser for changing gaseous carbon dioxide passed through the purifying unit into liquid carbon dioxide, a supply unit that includes a first pump for supplying the liquid carbon dioxide in the storage unit to a use point, and a return line through which excess carbon dioxide supplied from the supply unit but not used at the use point is returned to the storage unit; and a carbon dioxide introduction unit that introduces carbon dioxide, as a starting material or recovered gas, to the circulation system. The carbon dioxide introduction unit includes a second pump for increasing the pressure of the carbon dioxide and the second pump introduces the carbon dioxide to the circulation system.

A process may be utilized to coat urea-containing granules with organic polymers. The process may involve compressing gaseous carbon dioxide and condensing the carbon dioxide to obtain liquid carbon dioxide, increasing the pressure and/or the temperature above the critical point of carbon dioxide and obtaining supercritical carbon dioxide, dissolving an organic polymer in the supercritical carbon dioxide to obtain a polymer-containing solution, and mixing the polymer-containing solution with urea-containing granules and lowering the temperature and/or the pressure below the critical point of carbon dioxide and obtaining coated urea-containing granules and gaseous carbon dioxide. In some cases the organic polymer may include biodegradable polymers, and the polymer-containing solution may contain between 20 to 70% by weight biodegradable polymers.

A carbon dioxide separation and recovery system includes an exhaust gas sensible heat recovery part which recovers sensible heat of exhaust gas and generates electric energy by using the sensible heat of the recovered exhaust gas; a moisture removal part which is connected to the exhaust gas sensible heat recovery part and removes moisture contained in the sensible heat recovery exhaust gas from which the sensible heat is recovered by using the electric energy generated in the exhaust gas sensible heat recovery part; and a separation part which is connected to the moisture removal part to receive the sensible heat recovery exhaust gas from which moisture is removed by the moisture removal part, and separates solid carbon dioxide from the sensible heat recovery exhaust gas from which moisture is removed.

A process for recovering liquid hydrocarbons from a gaseous stream containing the liquid hydrocarbons, the process comprising (a) providing a dehydrated gaseous stream including carbon dioxide, methane, ethane, propane, and C4 and heavier hydrocarbons; (b) cooling the dehydrated gaseous stream to form a condensate stream including C4 and heavier hydrocarbons; (c) separating at least a portion of the carbon dioxide, methane and ethane from the condensate stream; and (d) distilling the condensate stream to thereby form a liquid hydrocarbon stream.

Processes and apparatuses for recovering a high purity carbon dioxide stream. A first separation zone that may include a cryogenic fractionation column provides the high-purity CO.sub.2 stream. A vapor stream from the cryogenic fractionation column is passed to a second separation zone to separate the CO.sub.2 from the other components. The second separation zone may include a pressure swing adsorption unit or a solvent separation unit. The second separation zone provides a hydrogen enriched gas stream that may be used in a gas turbine. The second stream from the second separation zone includes carbon dioxide and, after a pressure increase in a compressor, may be recycled to the first separation zone.

A carbon dioxide phase change energy storage and release method and system are provided. The method includes an energy storage step, and the energy storage step includes a condensation stage. The condensation stage includes a liquid-phase carbon dioxide purification process. In the condensation stage, gas-phase carbon dioxide is converted into liquid-phase carbon dioxide by a first phase change converter, when a stored liquid level of the liquid-phase carbon dioxide reaches a set liquid level, the liquid-phase carbon dioxide purification process is performed to remove impurity liquid from the liquid-phase carbon dioxide. Therefore, the impurity liquid in the liquid carbon dioxide can be purified in a targeted manner through the liquid-phase carbon dioxide purification process, thereby achieving precise impurity removal of precise objects, eliminating adverse effects of the impurity liquid on liquefaction temperature change of the system and corrosion of various equipment pipelines, and making the system more perfect and optimized.