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.

Systems and methods for the use of highly reactive hydrated lime (HRH) in circulating dry scrubbers (CDS) to remove sulfur dioxide (SO.sub.2) and other acid gases from the flue gas.

Process for treating flue gases in a circulating dry scrubber device wherein flue gases containing pollutants pass to a reactor where said flue gases contact a sorbent comprising high pore volume and high specific surface area slaked lime or hydrated lime being further sent to a particulate control device where said sorbent particles are separated from said flue gases substantially depleted in pollutants and form respectively a flow of flue gases substantially depleted in pollutant and a flow of sorbent particles being recycled and returned to said reactor.

Oxygen is removed from a gas feed such as a landfill gas, a digester gas or an industrial CO.sub.2 off-gas by heating the feed gas, optionally removing siloxanes and silanols from the heated feed gas, optionally removing part of the sulfur-containing compounds in the heated feed gas, injecting one or more reactants for oxygen conversion into the heated feed gas, carrying out a selective catalytic conversion of any or all of the volatile organic compounds (VOCs) present in the gas, including sulfur-containing compounds, chlorine-containing compounds and any of the reactants injected, in at least one suitable reactor, and cleaning the resulting oxygen-depleted gas. The reactants to be injected comprise one or more of H.sub.2, CO, ammonia, urea, methanol, ethanol and dimethyl ether (DME).

The invention relates to a method for cleaning flue gas, the flue gas to be cleaned and a sorption agent starting material in the form of a solid being injected into a reactor chamber of a fluidized-bed reactor, and a liquid being injected into the reactor chamber separately from the flue gas and the sorption agent starting material, the sorption agent starting material being contacted with the liquid in the fluidized-bed reactor and being converted to a sorption agent in the form of a solid.

A rechargeable battery assembly for a vehicle has a metal-air rechargeable battery and a filter device to condition inlet air supplied to the metal-air rechargeable battery such that the inlet air exhibits predetermined inlet air values. The filter device has one or more filter elements, one or more sensor devices that determine at least one inlet air parameter, and one or more valve devices. A control system is coupled to the sensor devices so as to receive sensor signals for the at least one inlet air parameter and is coupled to the valve devices. The control system adjusts, depending on the received sensor signals, the valve devices in order to control the predetermined inlet air value in that the inlet air is guided through the filter elements; is guided past the filter elements; or is guided to an air outlet for regenerating the filter elements.

Finely atomized alkaline sorbent salt solutions are injected into a hot flue gas stream to remove SO.sub.2. Flash evaporation of the droplets produces very fine dried sorbent particles, which react efficiently with SO.sub.2 in the flue gas. The liquid sorbent may be sodium carbonate, sodium hydroxide, sodium sulfite, potassium carbonate, potassium hydroxide or the like. In a coal-fired boiler, the liquid sorbent may be injected after the economizer section, where the flue gas temperature is below 850 F., and upstream of a particulate collection device. The dried sorbent particles react with SO.sub.2 and then are removed from the flue gas stream in the particulate collection device, producing a cleaned flue gas stream.

An electrostatic precipitator module and a desulfurization system are capable of easily discharging wash water from a wet electrostatic precipitator module. The electrostatic precipitator module includes an arrangement of discharge electrodes and collecting electrodes alternately disposed and spaced apart from each other, the discharge electrodes configured to be charged to a predetermined voltage for generating a corona discharge between the discharge electrodes and the collecting electrodes; and tie rods for fixing the discharge electrodes and the collecting electrodes. Each collecting electrode has a lower edge inclined downward with respect to the ground. The lower edge of each collecting electrode includes separate lower edge portions respectively inclined downward from opposite side ends of the collecting electrode and a lowermost point at which wash water is concentrated and discharged to a discharge guide installed directly under the lowermost points. The discharge guide has a width substantially smaller than the collecting electrode.

Calcium hydroxide-containing compositions can be manufactured by slaking quicklime, and subsequently drying and milling the slaked product. The resulting calcium hydroxide-containing composition can have a size, steepness, pore volume, and/or other features that render the compositions suitable for treatment of exhaust gases and/or removal of contaminants. In some embodiments, the calcium hydroxide-containing compositions can include a D.sub.10 from about 0.5 microns to about 4 microns, a D.sub.90 less than about 30 microns, and a ratio of D.sub.90 to D.sub.10 from about 8 to about 20, wherein individual particles include a surface area greater than or equal to about 25 m.sup.2/g.

Materials which react with (scavenge) sulfur compounds, such as hydrogen sulfide and mercaptans, are useful for limiting sulfur-induced corrosion. Surface-modified particles incorporating a hexahydrotriazine moiety are disclosed and used as sulfur scavengers. These surface-modified particles are used a filter media in fixed filter systems and as additives to fluids including sulfur compounds. The hexahydrotriazine moiety can react with sulfur compounds in such a manner as to bind sulfur atoms to the surface-modified particles, thus allowing removal of the sulfur atoms from fluids such as crude oil, natural gas, hydrocarbon combustion exhaust gases, sulfur polluted air and water. The surface-modified particles may, in general, be sized to allow separation of the particles from the process fluid by sedimentation, size-exclusion filtration or the like.