Disclosed are methods and systems for removing submicron particles from a gas stream, in particular from urea prilling off-gas, wherein a Venturi ejector is used. A method comprises contacting a gas stream containing submicron particles in a Venturi ejector with an injected high velocity scrubbing liquid to provide a pumping action, wherein the scrubbing liquid has an initial velocity of at least 25 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h).

An engine exhaust system includes an exhaust pipe assembly having an engine exhaust system inlet configured to receive engine exhaust and an engine exhaust system outlet. The system includes a first selective catalytic reduction (SCR) catalyst device positioned downstream in exhaust flow from the engine exhaust system inlet. The first SCR catalyst device includes a substrate with a metallic catalyst coated on the substrate. An electric heater is configured to heat the metallic catalyst. A second SCR catalyst device is positioned downstream in engine exhaust flow from the first SCR catalyst device and upstream of the engine exhaust system outlet. The first SCR catalyst device and the exhaust pipe assembly define an empty chamber between the substrate and the second SCR catalyst device. Engine exhaust flows directly from the substrate to the second SCR catalyst device through the empty chamber.

Described is a selective catalytic reduction material comprising a spherical particle including an agglomeration of crystals of a molecular sieve. The catalyst is a crystalline material that is effective to catalyze the selective catalytic reduction of nitrogen oxides in the presence of a reductant at temperatures between 200° C. and 600° C. A method for selectively reducing nitrogen oxides and an exhaust gas treatment system are also described.

A two-stage mixer may include a guiding element and a mixing element. The guiding element may be configured to be fixedly mounted to an interior of an exhaust conduit. The mixing element may be configured to be fixedly mounted to the interior of the exhaust conduit in a position downstream from the guiding element. The mixing element may include a central disk, a plurality of mounting arms extending radially from the central disk, and a plurality of blades extending radially from the central disk. At least one mounting arm of the plurality of mounting arms may include a fin extending therefrom, and at least one blade of the plurality of blades may include a fin extending therefrom.

This exhaust gas purifying catalyst is provided with a substrate and a catalyst layer formed on a surface of the substrate. The catalyst layer contains zeolite particles that support a metal, and a rare earth element-containing compound that contains a rare earth element. The rare earth element-containing compound is added in such an amount that the molar ratio of the rare earth element relative to Si contained in the zeolite is 0.001 to 0.014 in terms of oxides.

To provide an exhaust purifying system and a method for controlling the exhaust purifying system that avoid occurrence of clogging, breakage, or the like of a reducing agent injection valve caused by the solidification of a reducing agent and prevent reduction in the efficiency of reducing agent recovery processing and exhaust gas purification. An exhaust purifying system and a method for controlling the exhaust purifying system according to an aspect of the present invention is configured to detect the injection valve temperature of the reducing agent injection valve according to detection of turn-off of an ignition switch for stopping the internal combustion engine or detection of an injection stop of the reducing agent injection valve, whichever is earlier, calculate the waiting time until reducing agent recovery processing starts based on the injection valve temperature, and permits the reducing agent recovery processing under condition of the detection of turn-off of the ignition switch and an elapse of the waiting time.

A urea tank for an SCR aftertreatment system, and a tank cover thereof. The tank cover is mounted at a liquid injection port of a tank body of the urea tank. An air hole is provided in a portion of the tank cover corresponding to the liquid injection port. The air hole is covered by a water-blocking air-permeable film (5). A gas inlet hole and a gas discharge hole (11) are further provided in the portion of the tank cover corresponding to the liquid injection port. A first constant pressure check valve (3) and a second constant pressure check valve (4) are mounted on the tank cover. An inlet of the first constant pressure check valve (3) is connected to the gas discharge hole (11). An outlet of the first constant pressure check valve (3) communicates with the exterior of the tank body. An inlet of the second constant pressure check valve (4) is connected to the gas inlet hole. An outlet of the second constant pressure check valve (4) communicates with the interior of the tank body.

Disclosed herein is a new crystalline molecular sieve designated SSZ-106, its synthesis in the presence of a structure directing agent comprising 2,3-bis(N-methylpyrrolidin-1-ylmethyl)bicyclo[2.2.1]heptane dication, and its use as an adsorbent and a catalyst.

An exhaust system, especially for an internal combustion engine of a vehicle, includes an exhaust gas-carrying duct (14) and a reactant injection device (20) for injecting reactant (R) into exhaust gas (A) flowing in the exhaust gas-carrying duct (14). Downstream of the reactant injection device (20), a mixer device (22) supports the mixing of reactant (R) injected by the reactant injection device (20) with exhaust gas (A) flowing in the exhaust gas-carrying duct (14). Downstream of the reactant injection device (20) and upstream of the mixer device (22), a reactant heating device (24) extends in the exhaust gas-carrying duct (14). The exhaust gas (A) flows in and reactant (R) injected through the reactant injection device (20) flow around the heating device (24).

The present invention relates to a catalyst comprising at least one oxide of vanadium, at least one oxide of tungsten, at least one oxide of cerium, at least one oxide of titanium and at least one oxide of antimony, and an exhaust system containing said oxides.