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.

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.

A carbon dioxide composite getter comprising a CO.sub.2-permeable envelope containing powders of two active materials and sealed systems employing the carbon dioxide composite getter.

The present invention generally relates to compounds, systems, and methods for adsorption of CO.sub.2 onto nanoclusters.

An exhaust treatment apparatus includes a casing having an inlet port for allowing an exhaust gas to flow into the casing and an outlet port for allowing a purified exhaust gas to be discharged from the casing, an exhaust fan provided in the casing for sending the exhaust gas from the inlet port to the outlet port, and chemical filters provided in two or more stages between the exhaust fan in the casing and the outlet port.

In one aspect, the invention provides a method for the capture of at least one acid gas in a composition, the release of said gas from said composition, and the subsequent regeneration of said composition for re-use, said method comprising performing, in order, the steps of: (a) capturing the at least one acid gas by contacting said at least one gas with a capture composition comprising at least one salt of a carboxylic acid and at least one water-miscible non-aqueous solvent; (b) releasing said at least one acid gas by adding at least one protic solvent or agent to said composition; and (c) regenerating the capture composition by partial or complete removal of said added protic solvent or agent from said composition. Optionally, said capture composition comprising at least one salt of a carboxylic acid and at least one water-miscible non-aqueous solvent additionally comprises water or another protic solvent. In another aspect, the invention envisages a composition which additionally comprises at least one protic solvent or agent and release of the at least one acid gas is achieved solely by subjecting the composition to the application of heat or stripping with a stream of air. The method is typically applied to the capture and subsequent release of carbon dioxide, and offers a convenient and simple process which uses inexpensive consumables and offers significant advantages over the methods of the prior art.

A process and an apparatus for gas denitration, involving first the use of an oxidizing agent to oxidize NO in a gas to NO.sub.2, then using a denitration agent to absorb the NO.sub.2 in the gas, thus achieving the purpose of denitration.