A method of reducing NO.sub.x in tail gas obtained during startup of a plant for preparing nitric acid may involve heating the tail gas from a starting temperature T.sub.0, through a threshold temperature T.sub.G, to an operating temperature T.sub.B at which steady-state operation of the plant can occur (T.sub.0<T.sub.G<T.sub.B). NO.sub.x-containing tail gas may be passed through a storage medium and at least partially stored while the temperature of the tail gas is lower than the threshold temperature T.sub.G. The NO.sub.x may be released, preferably when the temperature of the tail gas has attained the threshold temperature T.sub.G. The NO.sub.x may be combined with a reducing agent in the presence of an SCR catalyst after the temperature of the tail gas has exceeded the threshold temperature T.sub.G, but not before, resulting in catalytic reduction of at least a portion of the NO.sub.x.

A mercury sorbent and method for enhancing mercury removal performance of activated carbon from flue gas by the addition of non-halogen ammonium-containing compounds are provided herein.

Provided is an injection device capable of suppressing the deposition of white products and performing an exhaust gas purification treatment. This injection device is provided with: an injection unit which is provided upstream of a selective reduction-type catalyst device provided inside an exhaust pipe constituting an exhaust passage of an internal combustion engine, and injects a urea aqueous solution or a diethylamine aqueous solution; a determination unit which determines whether white products derived from the urea aqueous solution injected by the injection part are deposited.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

Apparatus and methods for controlling ammonia escape in an ammonia-based decarbonization system, wherein ammonia may be used as the desulfurization and decarbonization agent, the gas may first enter the desulfurization device for desulfurization to produce ammonium sulfate fertilizer, and the desulfurized gas may enter the decarbonization device to remove carbon dioxide in the gas, and may produce ammonium bicarbonate fertilizer. The decarbonized gas may include free ammonia, and the free ammonia in the gas may be absorbed with the acidic ammonium sulfate solution and acidic water washing liquid of ammonia-based desulfurization.

The present invention relates to a method for producing automobile exhaust gas catalytic converters, to the catalytic converters as such and to the use thereof. In particular, the method comprises a step which results, independently of the actual drying process, in the catalytically active material used being dried. The invention is especially used in the coating of wall-flow filters.

The present invention relates to a method for producing automobile exhaust gas catalytic converters, to the catalytic converters as such and to the use thereof. In particular, the method comprises a step which results in a smaller particle size of the catalytically active material used.

A vehicle exhaust system includes an exhaust gas aftertreatment component and an exhaust duct positioned downstream of the exhaust gas aftertreatment component. The exhaust duct defines an internal cavity and a mixer is positioned within the internal cavity. A sensor is configured to sample exhaust gas downstream of the mixer.

An exhaust aftertreatment system for use with an automotive diesel engine, the system includes a selective catalytic reduction unit a reagent storage tank, and a reagent distribution system. A reagent fluid is stored in the reagent storage tank. The reagent is delivered to exhaust gases produced by the engine using the reagent distributor. The selective catalytic reduction unit is positioned downstream of the reagent distributor and is configured to remove effluents from the exhaust gases.

A gas combustion treatment device that subjects an ammonia-containing gas, a hydrogen cyanide-containing gas, and a hydrogen sulfide-containing gas to combustion treatment includes: a first combustion unit configured to introduce therein fuel, the ammonia-containing gas, the hydrogen cyanide-containing gas, and air and burn and reduce the fuel and the gases at an air ratio lower than 1; a second combustion unit provided downstream of the first combustion unit and configured to burn and reduce, in a reducing atmosphere, nitrogen oxide in a first combustion gas sent from the first combustion unit; and a third combustion unit provided downstream of the second combustion unit and configured to introduce therein hydrogen sulfide-containing gas with air in addition to a second combustion gas sent from the second combustion unit.