Catalyst compositions and methods of preparation comprising: exchanging a rare earth element into a molecular sieve; incorporating a promoter metal into the molecular sieve; wherein the rare earth element exchanging step and the promoter metal incorporation step are performed as separate steps.

A method for producing a SNCR/SCR solution, comprising the steps of: a) reacting ammonia and carbon dioxide in a high pressure section, thereby obtaining an aqueous composition comprising urea and ammonium salts; b) processing the aqueous composition obtained in step a), thereby obtaining a first aqueous solution comprising urea, and a second aqueous solution comprising ammonium salts; and c) diluting the second aqueous solution comprising ammonium salts obtained in step b) with a third aqueous solution, thereby producing the SNCR/SCR solution. The present disclosure also provides the use of an aqueous stream comprising ammonium salts from a urea-producing plant for producing a SNCR/SCR solution.

The present invention relates to a copper-containing KFI-type zeolite, wherein the zeolite contains 1 to 4.5 wt.-% copper. The invention is also directed towards a method for producing the copper-containing zeolite according to the invention as well as towards the use of the zeolite in SCR catalysis. Further subjects of the invention are a washcoat which contains the zeolite according to the invention, an SCR catalyst which contains the zeolite according to the invention as well as an exhaust-gas cleaning system which comprises the SCR catalyst.

The invention provides a method and system for the purification of exhaust gas from an internal combustion engine, comprising a filter and a SCR catalyst. The filter is periodically regenerated increasing the temperature of the exhaust gas up to 850 C. and the water vapor content up to 100% by volume. The SCR catalyst comprises a hydrothermally microporous stable zeolite and/or zeotype having the AEI type framework and being promoted with copper.

The present invention is directed to a catalyst system for the reduction of the harmful exhaust-gas constituents hydrocarbons (THC), carbon monoxide (CO), nitrogen oxides (NO.sub.x), and the environmentally detrimental secondary emissions ammonia (NH.sub.3) and nitrous oxide (N.sub.2O) of combustion engines operated using gasoline and to a corresponding method for exhaust-gas purification. The system is characterized by a particular arrangement of catalysts and is used in the case of engines which are operated with predominantly, on average, stoichiometric air/fuel mixtures. Here, a three-way catalyst produced in accordance with the current prior art is preferably installed in a close-coupled position. In the underfloor position, there is situated an SCR catalyst produced in accordance with the current prior art, followed by a further three-way catalyst produced in accordance with the current prior art. The three-way catalyst in the underfloor region furthermore has a lower oxygen-storing capacity than the close-coupled three-way catalyst.

Organic sulfur compounds contained in refinery off gas streams having either high ort low concentrations of olefins are converted to hydrogen sulfides which can be then be removed using conventional amine treating systems. The process uses a catalytic reactor with or without a hydrotreater depending on the olefin concentration of the off gas stream. The catalytic reactor operates in a hydrogenation mode or an oxidation mode to convert a majority of organic sulfur compounds into hydrogen sulfides.

A formulation and process for capturing CO.sub.2 use an absorption mixture containing water, biocatalysts and a carbonate compound. The process includes contacting a CO.sub.2-containing gas with the absorption mixture to enable dissolution and transformation of CO.sub.2 into bicarbonate and hydrogen ions, thereby producing a CO.sub.2-depleted gas and an ion-rich solution, followed by subjecting the ion-rich solution to desorption. The biocatalyst improves absorption of the mixture comprising carbonate compounds and the carbonate compound promotes release of the bicarbonate ions from the ion-rich solution during desorption, producing a CO.sub.2 gas stream and an ion-depleted solution.

Methods and devices for controlling ammonia escape and soluble particulate matter formation in an ammonia-based carbon capture process are provided. After the process gas containing sulfur oxides and carbon dioxide may be treated by ammonia-based desulfurization and carbon capture, free ammonia contained in the tail gas may be removed by scrubbing the tail gas with sulfuric acid-containing solution and aqueous solution. The sulfuric acid reacts with ammonia to form ammonium sulfate, and the ammonium sulfate solution may be sent to an ammonia-based desulfurization system, where it may be crystallized together with the desulfurization byproduct ammonium sulfate to produce solid ammonium sulfate. By treating the ammonium sulfate solution in a membrane separation device, solution gradient control and system water balance may be achieved. The ammonia in the tail gas may be effectively removed, while the soluble particulate matter in the tail gas may be reduced.

A process for stabilizing nutrients in anaerobic digestate involves removing hydrogen sulfide and ammonia from biogas. This process involves circulating the digestate in a column and contacting it with the biogas. Additional ammonium bisulfite, ammonia, and/or sulfur dioxide may be added to the contacting device to remove hydrogen sulfide from the biogas. The reactions will create ammonium bisulfite, ammonium sulfite, and ammonium thiosulfate to prevent ammonia and hydrogen sulfide emissions to allow for land application.

In one aspect, the disclosure relates to a composition and a catalyst for substantially continuous CO.sub.2 capture and reduction from dilute CO.sub.2 sources including flue gas, wherein the flux of CO.sub.2 captured is substantially equal to the flux of CO.sub.2 reduction. The system can comprise integrated CO.sub.2 capture and reduction components. An exemplary system includes a composition of a catalyst and electrolytes. The catalyst can comprise supported or unsupported mesh electrodes that comprise Cu, a CuAl alloy, and/or a copper oxide. In one aspect, the system includes one or more membranes separating an anodic side from a cathodic side in the system, where the one or more membranes can be a bipolar membrane, an anion exchange membrane, or both, which can reduce or eliminate Cl.sub.2 production. In exemplary embodiments, the value-added products can be selected from CO, CH.sub.4, C.sub.2H.sub.4, C.sub.2H.sub.5OH, CH.sub.3COOH, CH.sub.3OH, C.sub.3H.sub.6, and/or H.sub.2.