A process is disclosed for reversibly absorbing carbon dioxide to an alkali metal or earth alkaline absorbent. For absorption the absorbent is contacted with a first gas composition. For desorption the absorbent is contacted with a second gas composition. The moisture contents of the first and second gas compositions are controlled so that during the absorption step the absorbent is converted to a bicarbonate, and during the desorption step the absorbent is converted to a carbonate hydrate. Compared to prior art processes the process of the invention requires less energy input. The process of the invention is particularly suitable for producing a carbon dioxide enriched gas for accelerating plant growth in a greenhouse.

A method for reducing pollution in exhaust gases and a system for treating exhaust gas are provided. The method includes the step of treating an exhaust gas stream with a treating fluid. In one application, the treating fluid is injected by spraying droplets into the exhaust gas stream. A system for treating exhaust gas includes a reagent, and a nozzle to spray the reagent into the exhaust gas stream.

A contaminated gas stream can be passed through an in-line mixing device, positioned in a duct containing the contaminated gas stream, to form a turbulent contaminated gas stream. One or more of the following is true: (a) a width of the in-line mixing device is no more than about 75% of a width of the duct at the position of the in-line mixing device; (b) a height of the in-line mixing device is no more than about 75% of a height of the duct at the position of the in-line mixing device; and (c) a cross-sectional area of the mixing device normal to a direction of gas flow is no more than about 75% of a cross-sectional area of the duct at the position of the in-line mixing device. An additive can be introduced into the contaminated gas stream to cause the removal of the contaminant by a particulate control device.

A hydrogen fluoride gas removal device has: a hydrogen fluoride gas removal treatment machine that is configured to perform a treatment of removing hydrogen fluoride gas from the mixed gas by bringing the mixed gas into contact with a removal agent for removing the hydrogen fluoride gas from the mixed gas; a removal agent supply machine that is configured to supply the removal agent to the hydrogen fluoride gas removal treatment machine; a removal agent recycling treatment machine that is configured to perform a recycling treatment on the used removal agent to improve hydrogen fluoride gas removal performance of the removal agent; and a recycling-treated removal agent transport machine that is configured to transport the recycling-treated removal agent to supply the removal agent to the removal agent supply machine.

Provided are sorbents and associated methods and systems for removing mercury from process gases or fluid streams. The sorbents may include activated carbon and pyrite. The sorbents may optionally include one or more additives, such as a halide salt.

Provided are a filler-integrated cooler having a cooler body with cooling space, gas inlet and outlet and communicated with bottom and top of the cooling space, a cooling pipe in the cooling space between the gas inlet and outlet to make cooling fluid from a cooling-fluid inlet go around in the cooling space and discharge the same through a cooling-fluid outlet and a filler vertically partitioning the cooling space into portions with the gas inlet and outlet, a nozzle arranged above in the cooling space, a drain circulator supplying drain in a drain reservoir at inner bottom of the cooling space through a drain outlet to the nozzles, using a pump, and an alkaline-agent addition unit to add an alkaline agent to drain.

Systems and methods use oxygen uncoupling metal oxide material for decomposition of NO.sub.x. A gaseous input stream comprising NO.sub.x is contacted with a metal oxide particle, generating nitrogen (N.sub.2) gas and an oxidized metal oxide particle. After contacting the first gaseous input stream with the metal oxide particle, a first gaseous product stream is collected. The first gaseous product stream includes substantially no NO.sub.x. A second gaseous input stream comprising at least one sweeping gas is also contacted with the oxidized metal oxide particle. After contacting the oxidized metal oxide particle, the sweeping gas includes oxygen (O.sub.2) and a reduced metal oxide particle is generated. Then a second gaseous product stream is collected, where the second gaseous product stream includes oxygen (O.sub.2) gas.

A process is disclosed for reversibly absorbing carbon dioxide to an alkali metal or earth alkaline absorbent. For absorption the absorbent is contacted with a first gas composition. For desorption the absorbent is contacted with a second gas composition. The moisture contents of the first and second gas compositions are controlled so that during the absorption step the absorbent is converted to a bicarbonate, and during the desorption step the absorbent is converted to a carbonate hydrate. Compared to prior art processes the process of the invention requires less energy input. The process of the invention is particularly suitable for producing a carbon dioxide enriched gas for accelerating plant growth in a greenhouse.

A contaminated gas stream can be passed through an in-line mixing device, positioned in a duct containing the contaminated gas stream, to form a turbulent contaminated gas stream. One or more of the following is true: (a) a width of the in-line mixing device is no more than about 75% of a width of the duct at the position of the in-line mixing device; (b) a height of the in-line mixing device is no more than about 75% of a height of the duct at the position of the in-line mixing device; and (c) a cross-sectional area of the mixing device normal to a direction of gas flow is no more than about 75% of a cross-sectional area of the duct at the position of the in-line mixing device. An additive can be introduced into the contaminated gas stream to cause the removal of the contaminant by a particulate control device.

The packing has one or more thin-layer packing elements that are installed upright, the packing element having a main body portion with a planar liquid film formation surface, and one or more wall portions that are provided upright relative to the liquid film formation surface along a linear direction. The side surface of each wall portion has a curved portion at the base thereof connected to the liquid film formation surface, the curved portion curbing so as to continue into the liquid film formation surface.