Disclosed are a method and system for controlling urea injection for selective catalyst reduction (SCR), capable of improving NOx purification efficiency by predicting an operating situation in which an amount of NOx production is rapidly increased using engine behavior and pre-occluding ammonia in advance. An opening state of an EGR valve may be detected at the time of rapid acceleration of a vehicle; a pressure condition in an intake manifold or an EGR valve pressure condition may be diagnosed according to the opening state of the EGR valve; and urea may be injected when the pressure condition meets an NOx excess production condition of rapidly increasing the amount of NOx production.

It is intended to provide a novel zeolite with a rare earth element-substituted framework which has a higher amount of NOx adsorbed and a method for producing the same, and a NOx adsorption member and a catalyst for automobile exhaust gas, etc. comprising the same. The present invention provides a zeolite with a rare earth element-substituted framework, comprising at least a zeolite and at least one rare earth element selected from the group consisting of Ce, La, Nd and Pr, wherein a content ratio of the rare earth element is 1 to 15% by mass in total based on the total amount, and one or some of Al and/or Si atoms constituting the framework of the zeolite are replaced with the rare earth element.

Disclosed are methods and compact apparatus for controlled, on-demand ammonia generation from urea. The process gasifies an aqueous urea solution in a chamber utilizing hot gas while controlling the flows of aqueous urea solution and hot gas to achieve complete gasification of the aqueous urea solution and form a gas mixture comprising ammonia, isocyanic acid, carbon dioxide and water vapor, which is passed through a catalyst bed containing particulate transition metal oxide to convert substantially all of the isocyanic acid to ammonia. A catalyst support and the catalyst bed are aligned with the gasification chamber at the lower end of said chamber to provide a degree of back pressure on the gases in the gasification chamber to isolate the gasification chamber from turbulent exit effects caused by equipment downstream of the thermal reactor. A sample of the product stream is treated to remove water and ammonia, and analyze for carbon dioxide content to control the process. The apparatus to perform the process includes flow managing equipment and catalyst supports that facilitate continuous operation with accurate control.

Disclosed are a method and system for controlling urea injection for selective catalyst reduction (SCR), capable of improving NOx purification efficiency by predicting an operating situation in which an amount of NOx production is rapidly increased using engine behavior and pre-occluding ammonia in advance. An opening state of an EGR valve may be detected at the time of rapid acceleration of a vehicle; a pressure condition in an intake manifold or an EGR valve pressure condition may be diagnosed according to the opening state of the EGR valve; and urea may be injected when the pressure condition meets an NOx excess production condition of rapidly increasing the amount of NOx production.

Provided through the present disclosure is a method for reducing nitrogen dioxide in exhaust gas of a stationary source by using selective catalytic reduction (SCR) without injection of a reducing agent, the method comprising the steps of: (a) providing exhaust gas generated in the stationary source wherein the exhaust gas includes at least one of CO, H.sub.2, and hydrocarbon; (b) contacting the exhaust gas with a catalyst to reduce nitrogen dioxide in the exhaust gas; and (c) discharging into air the exhaust gas that has undergone step (b).

Catalyst for oxygen storage capacity applications that include a zinc doped manganese-iron spinel mixed oxide material. The zinc doped manganese-iron spinel mixed oxide material may be synthesized by a co-precipitation method using a precipitation agent such as sodium carbonate and exhibits a high oxygen storage capacity.

A honeycomb structure includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells, wherein a major component of the partition wall is cordierite, a porosity of the partition wall is 45 to 55%, an average pore diameter of the partition wall is 8 to 19 μm, a cumulative pore volume of the partition wall is such that a pore volume ratio of the pores having a pore diameter larger than a thickness of the partition wall relative to an overall pore volume of the partition wall is 3.0% or less, and a pore volume ratio of the pores having a pore diameter of 10 μm or less relative to the overall pore volume of the partition wall is 30% or more, and a pore diameter distribution of the partition wall is a unimodal distribution, or a multimodal distribution.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall is composed of a material containing cordierite as a main component thereof, porosity of the partition wall measured by a mercury press-in method is 60 to 68%, an average pore diameter of the partition wall measured by a mercury press-in method is 13 to 18 μm, and in a pore diameter distribution indicating a cumulative pore volume of the partition wall measured by a mercury press-in method, with a pore diameter (μm) on an abscissa axis and a log differential pore volume (cm.sup.3/g) on an ordinate axis, a first peak including a maximum value of the log differential pore volume has a pore diameter value of 15 μm or less, the pore diameter value corresponding to a ⅓ value width of the maximum value.

A reactor for reducing the concentration of NOx in a stream comprising: an inlet for the stream; an outlet for a stream containing a reduced concentration of NOx; one or more catalyst beds comprising a ceramic or metallic foam with a NOx reduction catalyst; one or more flow paths from the inlet to the outlet that passes through at least one catalyst bed wherein the catalyst beds are closed at the top and bottom so that the flow path through the catalyst bed passes through the sides of the catalyst bed in a lateral flow is described.

A doser mounting bracket for coupling a doser to an exhaust gas aftertreatment system component having a sidewall and an exhaust gas aftertreatment system component opening includes a lower surface, an engagement wall, a central structure, an upper surface, and an attachment structure. The lower surface is configured to be held in a position opposing the sidewall. The engagement wall extends from the lower surface. The central structure has an opening that extends therethrough and includes a centering structure that extends from the lower surface and is configured to be received within the exhaust gas aftertreatment system component opening. The attachment structure extends from the upper surface and is configured to be coupled to the doser. The engagement wall is configured to separate the lower surface from the sidewall when the engagement wall interfaces with the sidewall such that a pocket is formed between the engagement wall, the centering structure, and the lower surface.