Described is a selective catalytic reduction catalyst comprising a zeolitic framework material of silicon and aluminum atoms, wherein a fraction of the silicon atoms are isomorphously substituted with a tetravalent metal. The catalyst can include a promoter metal such that the catalyst effectively promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H.sub.2O selectively over a temperature range of 150 to 650 C. In another aspect, described is a selective catalytic reduction composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state of IV. The SCR catalyst material promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H.sub.2O selectively over a temperature range of 150 C. to 600 C., and the SCR catalyst material is effective to store ammonia at temperatures of 400 C. and above. A method for selectively reducing nitrogen oxides, and a method for simultaneously selectively reducing nitrogen oxide and storing ammonia are also described. Additionally, an exhaust gas treatment system is also described.

The present invention relates to a process for the treatment of a gas stream containing nitrogen oxides comprising the steps of: (1) providing a gas stream containing one or more nitrogen oxides; (2) contacting the gas stream provided in step (1) with a transition metal containing zeolitic material having a BEA-type framework structure for reacting one or more of the nitrogen oxides; wherein the zeolitic material is obtainable from an organotemplate-free synthetic process, as well as to an apparatus for the treatment of a gas stream comprising containing nitrogen oxides.

A process for the removal of nitrous oxide (N.sub.2O) contained in a process off-gas in an axial flow reactor. The process includes the steps of (a) adding an amount of reducing agent into the process off-gas; (b) in a first stage passing in axial flow direction the process off-gas admixed with the reducing agent through a first monolithic shaped catalyst active in decomposing nitrous oxide by reaction with the reducing agent to provide a gas with a reduced amount of nitrous oxide and residual amounts of reducing agent; and (c) in a second stage passing the gas with a reduced amount of nitrous oxide and residual amounts of the reducing agent in axial flow direction through a second monolithic shaped catalyst active in oxidation of the residual amounts of the reducing agent.

An aftertreatment system includes: a selective catalytic reduction (SCR) system configured to decompose constituents of exhaust gas; an exhaust conduit configured to deliver the exhaust gas to the SCR system; a hydrocarbon insertion assembly; a valve operably coupled to the exhaust conduit, the valve configured to be selectively opened so as to allow a first gas to enter the exhaust conduit and mix with the exhaust gas; and a controller configured to: determine a SCR system temperature, in response to the SCR system temperature being less than a target temperature, instruct the hydrocarbon insertion assembly to insert hydrocarbons into the exhaust gas, and in response to the SCR system temperature being greater than the target temperature, instruct the valve to open so as to allow the first gas to enter the exhaust conduit, a first gas temperature of the first gas being lower than the SCR system temperature.

An aftertreatment system for reducing constituents of an exhaust gas having a sulfur content includes: an oxidation catalyst; a filter disposed downstream of the oxidation catalyst; and a controller configured to, in response to determining that the filter is to be regenerated and a desulfation condition being satisfied: cause a temperature of the oxidation catalyst to increase to a first regeneration temperature that is greater than or equal to 400 degrees Celsius and less than 550 degrees Celsius, cause the temperature of the oxidation catalyst to be maintained at the first regeneration temperature for a first time period, and after the first time period, cause the temperature of the oxidation catalyst to increase to a second regeneration temperature equal to or greater than 550 degrees Celsius.

The invention provides a device and system for decomposing and oxidizing of gaseous pollutants. A novel reaction portion reduces particle formation in fluids during treatment, thereby improving the defect of particle accumulation in a reaction portion. Also, the system includes the device, wherein a modular design enables the system to have the advantage of easy repair and maintenance.

A fluid injection device includes a valve body of a cylindrical shape and a valve member, which is movably accommodated in the valve body and which has a valve surface portion to be seated on or separated from a valve seat portion formed in an inside of the valve body. The valve member has an inside passage through which urea aqueous solution flows and a communication port, which is opened at an outer peripheral surface of the valve member and at a position of an upstream side of the valve surface portion in a flow direction of air. An annular fluid passage, through which the air flows, is formed between an inner peripheral surface of the valve body and the outer peripheral surface of the valve member. The communication port is connected to the annular fluid passage at a connecting passage portion. A cross-sectional passage area of the annular fluid passage at the connecting passage portion is smaller than a cross-sectional passage area of the annular fluid passage at an upstream-side passage portion thereof.

An exhaust aftertreatment system includes a diesel oxidation catalyst in exhaust gas receiving communication with an engine. A selective catalytic reduction catalyst on filter (SCR on filter) is positioned downstream of the diesel oxidation catalyst. A hydrocarbon doser is configured to inject hydrocarbons into a flow of the exhaust gas upstream of the diesel oxidation catalyst. A reductant doser is configured to inject reductant into the flow of the exhaust gas upstream of the SCR on filter and downstream of the diesel oxidation catalyst. An aftertreatment controller is operatively coupled to the hydrocarbon doser. The aftertreatment controller is configured to control a dosing rate at which the hydrocarbon doser injects hydrocarbons into the flow of the exhaust gas so as to cause regeneration of the SCR on filter.

The invention relates to a process (100), in which, with the inclusion of an air-separation method (10), an oxygen-rich substance flow (b) is formed, which is subjected with a methane-rich substance flow (e) to a method for oxidative coupling of methane (20). From a product flow (e) of the method for oxidative coupling of methane (20), a carbon-dioxide-rich substance flow (i) is formed and subjected to a urea-synthesis method (50). A corresponding combined plant also forms the subject matter of the invention.

Described is a process for the treatment of a gas stream containing nitrogen oxides. The process comprises the steps of: (1) providing a gas stream containing one or more nitrogen oxides; (2) contacting the gas stream provided in step (1) with a transition metal containing zeolitic material having a BEA-type framework structure for reacting one or more of the nitrogen oxides; wherein the zeolitic material is obtainable from an organotemplate-free synthetic process. Also described is an apparatus for the treatment of a gas stream comprising containing nitrogen oxides.