This invention provides a method of removing sulfur oxides, mercury vapor and other contaminants from a flue gas stream and a flue gas treatment device comprising a sorbent polymer composite substrate comprising a high surface area support and a durable halogen source adjacent the sorbent polymer composite substrate. The halogen source comprises a compound with a quaternary ammonium halogen salt that is not washed away.

Acid gas compounds are removed from a process gas such as, for example, syngas or natural gas, by flowing a feed gas into a desulfurization unit to remove a substantial fraction of sulfur compounds from the feed gas and flowing the resulting desulfurized gas into a CO.sub.2 removal unit to remove a substantial fraction of CO.sub.2 from the desulfurized gas.

Sorbent components containing halogen, calcium, alumina, and silica are used in combination during coal combustion to produce environmental benefits. Sorbents such as calcium bromide are added to the coal ahead of combustion and other components are added into the flame or downstream of the flame, preferably at minimum temperatures to assure complete formation of the refractory structures that result in various advantages of the methods. When used together, the components reduce emissions of elemental and oxidized mercury; increase the level of Hg, As, Pb, and/or Cl in the coal ash; decrease the levels of leachable heavy metals (such as Hg) in the ash, preferably to levels below the detectable limits; and make a highly cementitious ash product.

A gas purification agent includes an electronegative film-forming agent and a foaming agent. The electronegative film-forming agent accounts for 20-80 wt % of the gas purification agent, while the foaming agent accounts for 20-80 wt % of the gas purification agent. The gas purification agent of such a composition can be used as a haze removing agent to effectively remove fine dust particles such as PM10 and PM2.5 from the air. The gas purification agent includes 2.5-25 wt % of the electronegative film-forming agent, 2.5-25 wt % of the foaming agent, and 50-95 wt % of a desulfurizing agent. The gas purification agent of such a composition can be used as a desulfurizing agent to remove sulfur-containing compounds from industrial exhaust gases. A method for using the gas purification agent is also provided.

In one embodiment, a separation membrane includes: a porous support structure, wherein the porous support structure comprises a system of continuous pores connecting an inlet of the separation membrane to an outlet of the separation membrane; and at least one alkali metal hydroxide disposed within pores of the porous support structure. Other aspects and embodiments of the disclosed inventive concepts will become apparent from the detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.

A system for cleaning flue gas, the system including a particulate removal system; an additive injector positioned downstream of the particulate removal system, for injecting an additive into the flue gas; a powdered sorbent injector positioned downstream of the additive injector, for injecting powdered sorbents, wherein no powdered sorbent injectors are positioned upstream of the particulate removal system; and a flue gas desulfurization system positioned downstream from the powdered sorbent injector, wherein no other processing apparatus is located between the powdered sorbent injector and the flue gas desulfurization system.

The present invention provides processes for filtering undesired chemicals in streams of contaminated air for supply to confined areas. The processes provide (1) contacting air with a filter comprising by volume from about 5% to about 95% impregnated zirconium hydroxide, from about 5% to about 95% activated impregnated carbon, and optionally, up to about 50% ammonia removal material; and (2) supplying the contacted air to a confined area.

Dry processes, apparatus, compositions and systems are provided for reducing emissions of sulfur oxides, and sulfur dioxide in particular, and/or HCl and/or Hg in a process employing a combination of a lime-based sorbent, in particular hydrated lime and/or dolomitic hydrated lime, and a sorbent doping agent administered to achieve coverage of a three-dimensional cross section of a passage carrying SO.sub.x and/or HCl and/or Hg-containing gases with a short but effective residence time at a temperature effective to provide significant sulfur dioxide and/or HCl and/or Hg reductions with high rates of reaction and sorbent utilization. The once-through, dry process can advantageously introduce the sorbent and sorbent doping agent dry or preferably as a slurry to enable uniform treatment. Preferred sorbent doping agents include water-soluble or water-dispersible copper and/or iron compositions which can be heated to an active form in situ by the flue gases being treated.

In one embodiment, a separation membrane includes: a porous support structure; and at least one alkali metal hydroxide disposed within pores of the porous support structure. In another embodiment, a method for separating acidic gases from a gas mixture includes exposing the gas mixture to a separation membrane at an elevated temperature, where the separation membrane includes a porous support and at least one molten alkali metal hydroxide disposed within pores of the porous support.

A granular sorption material including a plurality of porous granules formed by buildup agglomeration for separation, especially absorption, of harmful gases, especially of SO.sub.X and/or HCl, from offgases of thermal processes. The granules containing greater than 80% by weight, and preferably greater than 95% by weight, of Ca(OH).sub.2 and/or CaCO.sub.3 based on the dry mass. The granules having a dry apparent density ρ, determined by means of an apparent density pycnometer, of 0.5 to 1.2 kg/dm.sup.3, preferably 0.7 to 1.1 kg/dm.sup.3, and/or a porosity of 45% to 73% by volume, preferably 55% to 65% by volume, and have especially been increased in porosity. A process for producing the granular sorption material, in which pores are introduced into the granules by means of a porosity agent during the production.