A fuel gas cooling apparatus includes a cooling duct which causes a cooling gas to flow out into a mixing duct, and a difference of maximum dimensions in a height direction of a flow inlet and a flow outlet with respect to a passage length of the mixing duct is smaller than a difference of maximum dimensions in the height direction of a flow inlet and a flow outlet with respect to a passage length of an expanded duct, or a difference of maximum dimensions in a width direction of the flow inlet and the flow outlet with respect to the passage length of the mixing duct is smaller than a difference of maximum dimensions in the width direction of the flow inlet and the flow outlet with respect to the passage length of the expanded duct.

A diesel particulate filter coated with selective catalytic reduction includes: a support in which channels are formed from a front side to a rear side, a perovskite catalyst, and a selective catalytic reduction. In particular, the channels include an inlet channel which has an opened inlet and a closed outlet, and an outlet channel which is disposed adjacent to the inlet channel and has a closed inlet and an opened outlet. The perovskite catalyst is provided in an inner surface of the inlet channel, and the selective catalytic reduction is provided in an inner surface of the outlet channel. The perovskite catalyst is represented as La.sub.1xAg.sub.xMnO.sub.3 (here, 0<X<1).

Unique SCR catalyst including multiple washcoat formulations with differing performance characteristics are disclosed. One exemplary embodiment is an apparatus including a catalyst substrate defining a plurality of flow channels leading from an inlet to an outlet, a first washcoat composition distributed over a first portion of the flow channels, and a second washcoat composition distributed over a second portion of the flow channels. The first washcoat composition has a lower ammonia storage density than the second washcoat composition.

A method for removal of SO.sub.x and NO.sub.x from an exhaust gas that contains SO.sub.x, NO.sub.x, soot and water vapor, the exhaust gas originating from a combustion of a fuel where the combustion takes place in an internal combustion engine. The exhaust gas is passed through at least one catalytic reactor having an oxidation catalyst, in which catalytic reactor at least SO.sub.2 is converted to SO.sub.3 and NO is converted to NO.sub.2. Thereafter the exhaust gas is passed through a condenser and cooled to a temperature which is below the dew point temperature of the water in the condenser such that SO.sub.3, NO.sub.2 and water is condensed and SO.sub.3 and NO.sub.2 is dissolved into the condensed water and removed from the exhaust gas.

Provided is a denitration catalyst with an improved wear resistance capable of stably reducing and removing nitrogen oxides in flue gases for a long period of time and a production method therefor. A denitration catalyst obtained by having a honey comb molded body that contains at least titanium oxide and vanadium pentoxide support magnesium surface, and wherein the peak intensity ratio of the first peak of the magnesium sulfate to the first peak of the titanium oxide in X-ray diffraction is 0.05-0.15, the content of the magnesium sulfate increases by 6-22% by mass, the pore volume is 0.17-0.40 cc/g, and the specific surface area is 33-100 m.sup.2/g.

System and methods for reducing secondary emissions in an exhaust stream from an internal combustion engine are disclosed. The systems and methods include a filtration device positioned downstream from an SCR catalyst of an aftertreatment system disposed in the exhaust system. The filtration device can also be used for particulate filter diagnostics and for treatment of ammonia slip.

The object of the present invention is to provide an exhaust gas purifying catalyst, exhibits excellent performance for methane purification. The object can be solved by the exhaust gas purifying catalyst comprising a substrate and a catalyst layer provided on the substrate, in which the catalyst layer comprises at least one member selected from the group consisting of vanadium, niobium and tantalum; and platinum, and/or palladium.

Described are base metal catalysts that comprise a base metal material in an amount effective to generate an exotherm over a temperature range of 300 C. to 650 C. and to oxidize soot collected by a downstream particulate filter. The base metal catalysts are substantially free of platinum group metals. Emission treatment systems and methods of remediating nitrogen oxides (NO.sub.x), particulate matter, and gaseous hydrocarbons using base metal catalyst are also described.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, an ammonia source, and a first ammonia injector in fluid communication with the ammonia source. The first ammonia injector is configured to inject ammonia into the exhaust gas pathway at a first rate. The exhaust gas treatment system also includes a first treatment element positioned downstream of the first ammonia injector and a second ammonia injector in fluid communication with the ammonia source and positioned downstream of the first treatment element. The second ammonia injector is configured to inject ammonia into the exhaust gas pathway at a second rate different from the first rate. The exhaust gas treatment system further includes a second treatment element positioned downstream of the second ammonia injector.

The invention relates to a method for the operation of an exhaust gas aftertreatment system in an exhaust tract of an internal combustion engine. The exhaust gas aftertreatment system includes an SCR particle filter, a first reducing agent feed device for introducing the reducing agent into the exhaust tract upstream of the SCR particle filter, continuous regeneration of the SCR particle filter being possible using nitrogen dioxide as oxidizing agent, an SCR catalytic converter element arranged downstream of the SCR particle filter, and a second reducing agent feed device for introducing the reducing agent into the exhaust tract downstream of the SCR particle filter and upstream of the SCR catalytic converter element. A control unit regulates a quantity of reducing agent introduced into the exhaust tract by the first reducing agent feed device and/or by the second reducing agent feed device as a function of the temperature (TscR-PF) of the SCR particle filter.