288results about "Nitrous oxide capture" patented technology

The utility model relates to a purification device for nitric oxide gas. The purification device comprises an extraction tower, a desorption tower, an alkaline washing tower, a condenser, an ethanol absorption tower and an adsorption tower which are communicated in sequence, a feed port of the extraction tower is communicated with a crude product gas source pipeline, a discharge port of the extraction tower is communicated with a feed port pipeline of the desorption tower, a discharge port of the desorption tower is communicated with a feed port pipeline of the alkaline washing tower, a discharge port of the alkaline washing tower is communicated with a feed port pipeline of the condenser, and a discharge port of the condenser is communicated with a feed port pipeline of the ethanol absorption tower. A discharge port of the ethanol absorption tower is communicated with a feed port of the adsorption tower through a pipeline, and a discharge port of the adsorption tower is communicated with a product collection bottle through a pipeline. Through the extraction tower, the desorption tower, the alkaline washing tower, the condenser, the ethanol absorption tower and the adsorption tower which are arranged in sequence, the device can efficiently purify nitric oxide gas, and each treatment unit can remove specific impurities, so that the finally obtained nitric oxide gas is ensured to have high purity.

The invention belongs to the field of chemical engineering manufacturing industry, and relates to equipment and a method for producing cyclic ketone compounds by oxidizing cycloolefin by using waste gas produced by adipic acid. Raw material gas A containing nitrous oxide from an adipic acid production process production line can be subjected to oxygen removal, so that the oxygen content is less than 100ppm; the raw material gas A containing nitrous oxide from the adipic acid production line can also be purified into purer gas containing 50-99% of N2O, and the purer gas is used for reacting with the cycloolefin compound; the reaction equation is CnH2n-2 (cycloolefin) + N2O (nitrous oxide)-> CnH2n-2O (a product cyclic ketone compound) + a byproduct + N2 superscript (nitrogen), wherein n is a positive integer from 4 to 24. The device is stable in consumption quota, low in production cost and high in economic benefit compared with the prior art.

The invention discloses an intermittently-discharged high-concentration NO tail gas conversion and removal system and method. Comprising a high-concentration NO tail gas discharge port, a tail gas conversion turbulent flow section, a frequency modulation booster fan, a multi-stage pre-absorption tower, an alkali liquor spraying module, an alkali liquor supplementing port, an alkali liquor discharge port, a low-concentration NO / NO2 rapid oxidation module, a deep removal absorption tower, a high-concentration NO concentration measurement module and a composite regulation control module, according to the high-concentration NO tail gas conversion and removal composite regulation and control method, the thought of conversion, pre-absorption, rapid oxidation and deep removal is adopted, a database matrix large model control system is constructed, accurate and rapid regulation and control of the active molecule dosage are achieved, the active molecule excess coefficient is reduced, the method has the advantages of being high in removal efficiency and low in operation cost, and the method is suitable for industrial production. And the automation and intelligence level of the system is high.

The invention relates to the technical field of catalysts, in particular to a composite catalyst for nitrous oxide decomposition and a preparation method thereof.The composite catalyst is of a three-dimensional flower-shaped structure and comprises a composite carrier and active metal loaded on the composite carrier; the composite carrier is composed of a modification additive and a carrier oxide; the performance additive is composed of alkali metal oxide and rare earth metal oxide; the carrier oxide is selected from one of aluminum oxide, titanium dioxide and silicon dioxide; the active metal comprises cobalt oxide and vanadium oxide. The multi-metal catalyst has the advantages that the multi-metal catalyst with a three-dimensional flower-shaped structure is formed by loading cobalt and vanadium active metals on aluminum oxide and under the synergistic effect of alkali metal and rare earth metal, so that the stability and durability of the catalyst in a high-temperature environment are remarkably improved.

The invention relates to the technical field of biological denitrification, in particular to a nitrogen-doped carbon dot-based microbial electronic control denitrification system and application thereof. The system comprises electron donor microorganisms, electron acceptor microorganisms and nitrogen-doped carbon dots, the nitrogen-doped carbon dots serve as electron mediators outside cells, an efficient extracellular electron transfer network is constructed, and interspecific electron transfer resistance is reduced; meanwhile, the nitrogen-doped carbon dots can regulate and control intracellular electron transport chains and the energy metabolism process, the improvement of the reducing power and the energy level is promoted, and the metabolism mode optimization is realized. By cooperatively regulating and controlling generation, transmission and utilization of electrons under an extreme electron donor limited oligotrophic condition, the system disclosed by the invention can realize efficient denitrification, avoid nitrite accumulation, remarkably inhibit generation of nitrous oxide (N2O), reduce dependence on an external organic carbon source and an electron source, and improve the denitrification efficiency. And a new technical approach is provided for improving the deep denitrification efficiency under the low-carbon condition.

An exhaust gas aftertreatment system in the exhaust gas system of an ammonia combustion engine, wherein the exhaust gas system can be traversed by an exhaust gas flow of the ammonia combustion engine, including a passive SCR catalyst, an oxidation catalyst with which ammonia contained in the exhaust gas flow can be oxidized, and a regulated SCR catalyst. The oxidation catalyst is arranged in the exhaust gas system downstream of the passive SCR catalyst and the regulated SCR catalyst is arranged in the exhaust gas system downstream of the oxidation catalyst. The exhaust gas aftertreatment system further comprises at least one N2O decomposition catalyst arranged in the exhaust gas system upstream of the passive SCR catalyst or downstream of the passive SCR catalyst, the oxidation catalyst, and / or the regulated SCR catalyst.

The application discloses a N2O decomposition catalyst taking waste and old rare earth-based denitration catalyst as raw material and a preparation method thereof, and the catalyst is prepared from the waste and old rare earth-based denitration catalyst, diatomite and kaolin as a N2O decomposition catalyst carrier, and a nickel-lanthanum composite oxide (NiLaO x ) as a catalytically active component. The waste and old rare earth-based denitration catalyst, diatomite and kaolin are prepared into the carrier through crushing, batching and calcining processes, a nickel-lanthanum composite oxide precursor is configured into a colloidal solution, then the carrier is immersed in the nickel-lanthanum composite oxide precursor colloidal solution, and the N2O decomposition catalyst is obtained through drying and calcining. The catalyst not only realizes harmless disposal of the waste and old rare earth-based denitration catalyst, but also uses the waste and old rare earth-based denitration catalyst as a high-value resource for N2O decomposition, and the catalyst has high N2O decomposition activity and strong stability.

Disclosed is a waste gas treatment apparatus for semiconductor and display processes, the apparatus including: a pre-treatment unit having an inlet and an outlet formed therein, and configured to spray a cleaning solution to waste gas introduced through the inlet to primarily treat in the waste gas; a reaction unit configured to simultaneously treat fluorine compounds and nitrous oxide (N2O) in waste gas discharged from the pre-treatment unit; a post-treatment unit configured to spray a cleaning solution to waste gas discharged from the reaction unit to secondarily treat in the waste gas; and a heat exchange unit installed between the pre-treatment unit and the reaction unit.

The invention discloses preparation of a nickel and cerium doped cobalt-based catalyst and application of the nickel and cerium doped cobalt-based catalyst in catalytic decomposition of nitrous oxide. The nickel and cerium doped cobalt-based catalyst is of a Ni and Ce co-doped spinel type Co3O4 structure and has a mesoporous structure, and the molar ratio of cobalt to nickel to cerium is 1: 0.12: 0.04. The preparation method comprises the following steps: preparing a mixed solution in which the molar ratio of cobalt nitrate to nickel nitrate to cerium nitrate is 1: 0.12: 0.04 by adopting a coprecipitation method, adding sodium carbonate as a coprecipitator into the mixed solution, adjusting the pH value of the mixed solution to 9 while stirring, carrying out coprecipitation and aging, then washing and drying the precipitate, and roasting for 3 hours in an air atmosphere at 300-400 DEG C to obtain the nickel and cerium doped cobalt-based catalyst. The catalyst provided by the invention has good low-temperature nitrous oxide decomposition capability and anti-interference capability under complex working conditions.

The present invention relates to a zeolitic material having an AEI-type framework structure comprising SiO2, Al2O3 and B2O3, wherein the Al:B molar ratio of the zeolitic material, is comprised in the range of from 3 to 500, and wherein the zeolitic material displays an Si:(Al+B) molar ratio of the zeolitic material, which is comprised in the range of from 2 to 11. The present invention also relates to a process for the preparation of the zeolitic material according to the present invention, to a process for the treatment of NOx by selective catalytic reduction and to an apparatus for the treatment of a gas stream containing NOx, as well as to the use of a zeolitic material according to the present invention.

This invention provides a dual-effect catalyst for the simultaneous removal of NH3 and N2O, comprising a support and a coating applied to the surface of the support. The coating includes an inner coating and an outer coating. The inner coating adheres closely to the surface of the support, and the outer coating covers the surface of the inner coating. The inner coating comprises the following components: Pt, Co3O4, BaO, Al2O3, and TiO2. The outer coating comprises Cu-SSZ-13 and a binder. This invention uses barium-modified cobalt oxide to obtain a highly active N2O removal material. Simultaneously, the use of an Al2O3 and TiO2 composite coating combines the anti-poisoning properties of TiO2 with the high-temperature resistance of Al2O3, and reduces the N2O generation of traditional ASC catalysts. By combining the two catalysts and coating them on the same support, a dual-effect catalyst capable of simultaneously removing NH3 and N2O is obtained. This invention also provides a method for preparing the dual-effect catalyst for the simultaneous removal of NH3 and N2O. Research on the selection of catalyst precursors, component ratios, and post-treatment methods yields a highly active dual-effect catalyst.

To provide an exhaust gas treatment system capable of decomposing nitrous oxide in exhaust gas with high efficiency.SOLUTION: An exhaust gas treatment system 1 comprises an exhaust passage 10, a first catalyst device 11, a second catalyst device 21, and a third catalyst device 31. The first catalyst device 11 is arranged upstream of the second catalyst device 21. The first catalyst device 11 also has a first catalyst 12 that decomposes ammonia, and a dummy catalyst 13 that does not decompose ammonia. The first catalyst 12 includes a first active metal that decomposes ammonia, and a first carrier that carries the first active metal. The dummy catalyst 13 includes a dummy carrier that does not carry the first active metal.SELECTED DRAWING: Figure 1

The present invention relates to a process for removing nitrogen oxides, nitrous oxide and carbon monoxide from a gas stream (1), comprising: (a) oxidizing nitric oxide in the gas stream to form nitrogen dioxide by adding an oxygen-containing gas (3) to the gas stream (1), thereby obtaining a nitric oxide-depleted gas stream, and washing the nitric oxide-depleted gas stream with water (7) to obtain a nitric oxide-depleted gas stream (11) to remove nitrogen oxides from the gas stream (1); (b) oxidizing at least a portion of the carbon monoxide in the nitrogen oxide-depleted gas stream (11) to form carbon dioxide, thereby obtaining a carbon monoxide-depleted gas stream (19); (c) converting nitrous oxide in the carbon monoxide-depleted gas stream (19) to nitrogen and oxygen if the carbon monoxide-depleted gas stream (19) does not contain carbon monoxide, or converting nitrous oxide in the carbon monoxide-depleted gas stream to nitrogen and oxygen and / or carbon dioxide if the carbon monoxide-depleted gas stream (19) still contains carbon monoxide, or converting nitrous oxide in the carbon monoxide-depleted gas stream (19) to nitrogen and oxygen and / or carbon dioxide if the carbon monoxide-depleted gas stream (19) still contains carbon monoxide; to obtain a purified tail gas stream (25).

The present invention relates to a process for preparing a catalyst for the selective catalytic reduction of nitrogen oxide comprising, among other steps, preparing a second aqueous mixture comprising water and an iron salt; and disposing the second mixture on the substrate obtained according to (ii), comprising a coating comprising a zeolitic material comprising copper, over y % of the substrate axial length from the inlet end to the outlet end of the substrate, wherein y is in the range of from 10 to x, obtaining a substrate comprising, in a first zone, the coating comprising a zeolitic material comprising copper and over y % of the substrate axial length an iron salt; and, if x>y, in a second zone extending from y % to x % of the substrate axial length from the inlet end to the outlet end, the coating comprising a zeolitic material comprising copper.

The present application mainly relates to the technical field of pollution gas prevention and treatment, and particularly relates to a preparation method and application of a transition metal oxide catalyst for high-efficiency catalytic decomposition of N2O pollution. The preparation method is as follows: a specific surfactant is dissolved in deionized water, inorganic acid is added, stirring is performed until the mixture is miscible, transition metal nitrate is added, reaction is performed until a gel is formed, drying is performed to obtain a dry gel, calcination is performed, and the target catalyst is obtained. The prepared catalyst 10TX-Co3O4 has extremely high low-temperature catalytic activity, and the catalytic conversion rate of N2O reaches 90% at 300 DEG C; and under the condition of coexistence of O2, NO x , H2O impurity gas and N2O (simulated tail gas of a nitric acid plant), the catalyst still has high catalytic activity and stability (81% conversion rate at 400 DEG C). The present application provides a plurality of high-activity low-temperature catalysts for catalytic decomposition of N2O, and provides a wider train of thought for subsequent design of the catalyst and effective development and utilization of the additives.

The application belongs to the field of catalysts, and provides an alkali metal modified catalyst for decomposing nitrous oxide and a preparation method and application thereof. The catalysts Co / x%K / ZrO2 and Co / y%K / z%Cs / ZrO2 provided by the application both have high activity, good tolerance to impurity gases (NO x , H2O, O2), and excellent catalytic decomposition capacity of N2O under low temperature conditions, and the latter has better comprehensive performance. It is proved that the method of the application is an important strategy for designing an efficient and high-selectivity catalyst system, and solves the problem that there is no cobalt-based catalyst with high efficiency for decomposing N2O while having good tolerance to impurity gases.

The invention discloses a cobalt-based catalyst for producing ammonia through catalytic oxidation of nitrous oxide and nitric oxide as well as a preparation method and application of the cobalt-based catalyst, and belongs to the technical field of catalysts and environmental pollution. The preparation method of the cobalt-based catalyst comprises the following steps: (1) mixing a cobalt source, a carbon-containing nitrogen compound, a precipitator and a solvent for reaction to obtain a precursor solution; (2) putting the precursor solution into a high-pressure reaction kettle for hydrothermal reaction to obtain a solid, namely a precursor; and (3) performing pyrolysis treatment on the precursor in an inert atmosphere to obtain the cobalt-based catalyst. The cobalt-based catalyst prepared by the invention is applied to electrocatalytic conversion from N2O to NH3 for the first time, and shows excellent catalytic activity.

The invention relates to the technical field of gas impurity removal, and discloses a metal modified molecular sieve as well as a preparation method and application thereof. The method comprises the following steps: (1) mixing a metal salt, a nitrogen-containing micromolecule complexing agent, a nitrogen-containing micromolecule dispersing aid and ethanol to obtain a mixed solution, and then adding a molecular sieve for mixing to obtain a mixture; (2) drying the mixture obtained in the step (1), and then roasting; wherein the metal in the metal salt is selected from at least one of Mg, Ca, Sr and Ba; the nitrogen-containing micromolecule complexing agent is selected from at least one of 2-nitrophenol, 3-nitrophenol and 4-nitrophenol. The metal modified molecular sieve prepared by the method has very high adsorption activity on nitrous oxide, oxygen-enriched liquid air containing nitrous oxide is treated, the content of nitrous oxide can be reduced to 5 ppm or below, and the whole process is low in energy consumption, does not generate new impurities, and is green and environment-friendly.

The present disclosure relates to catalyst compositions, catalytic articles for purifying exhaust gas emissions, and methods of making and using the catalyst compositions and catalytic articles. In particular, the disclosure relates to catalysts having a catalytic material on a substrate, the catalytic material having a first layer and a second layer, where the first layer provides an effective lean NOx trap function and the second layer provides effective three-way conversion of carbon monoxide, hydrocarbons, and nitrogen oxides (NOx).

A process and system for purifying ammonia cracking reactor exhaust gas, comprising the steps of i) contacting the gas with an iron zeolitic catalyst at a temperature suitable to decompose N2O and pro

A method for purifying air through a pre-purification unit (PPU) of an air separation unit (ASU) system having a pre-PPU cooler located upstream of the PPU to cool the compressed air before it is sent to the PPU, the method may include the steps of passing air through an adsorber of the PPU to pass the air through a bed of adsorbent material within a vessel of the adsorber. In response to a determination that a problem exists with the pre-PPU cooler that causes the pre-PPU cooler to trip or require the pre-PPU cooler to be taken offline, the ASU system should continue to operate at full capacity even if nitrous oxide (N2O) in the air output of the PPU exceeds a first preselected threshold and is below a second preselected threshold associated with carbon dioxide (CO2) breakthrough. The ASU and PPU may be designed to implement embodiments of the method.

The invention discloses a carbon-supported metal catalyst for reducing N2O at low temperature with hydrogen and its application, and belongs to the field of air pollution control. The method uses H2 as a reducing agent, uses commercial activated carbon or coconut shell carbon to load metal nitrate, so that the load of metal is about 3 10wt.%;After the mixture is dissolved and dried by deionized water, it is calcined under N2 atmosphere, and then the metal active phase is reduced to a simple state under H2 atmosphere, so that it has reaction activity, and the preparation of the catalyst is completed;Then, in H2 atmosphere, the medium and low temperature (40 200 DEG C) reduction of N2O is realized. The catalyst efficiency of the present invention is high, and the activated carbon surface after the metal Ni load can reach 90% N2O removal rate under the conditions of 160 DEG C, and is low in price, effectively reducing the reduction cost of N2O, and the reaction products are all environmentally friendly (H2O and N2), without secondary pollution, and the catalyst life is longer.

This nitrous oxide decomposition catalyst contains a compound represented by formula (1).　(1): NiXA1-XCo2O4 (In formula (1), A represents at least one element that is selected from the group consisting of Fe, Mn, Ce, Zr, La, alkali metals and alkaline earth metals. In addition, X is more than 0 and less than 1.)

This application relates to the field of diesel engine exhaust gas treatment technology, and provides an aftertreatment system and a diesel engine. The aftertreatment system includes a first oxidation catalytic conversion module located downstream of the diesel engine's exhaust outlet; a particulate filter module located downstream of the first oxidation catalytic conversion module; a selective catalytic reduction module located downstream of the particulate filter module for reducing nitrogen oxides in the exhaust gas discharged from the particulate filter module; an ammonia oxidation catalytic module located downstream of the selective catalytic reduction module for oxidizing ammonia in the exhaust gas discharged from the selective catalytic reduction module; and a second oxidation catalytic conversion module located downstream of the ammonia oxidation catalytic module for decomposing nitrous oxide in the exhaust gas discharged from the ammonia oxidation catalytic module. Using this system can significantly improve exhaust gas treatment efficiency.

Provided is a flue gas treatment device configured to treat a flue gas discharged from a combustion device that combusts fuel containing ammonia, and the flue gas treatment device includes: an ammonia decomposition unit having an ammonia decomposition catalyst that decomposes ammonia contained in the flue gas; and a nitrogen oxide decomposition unit having a second catalyst that decomposes nitrous oxide and NOx contained in the flue gas in which ammonia was decomposed by the ammonia decomposition unit.

A method for reducing the NOx emission during start-up and shutdown events of a nitric acid plant, wherein the nitric acid plant comprises a tail gas treatment section (10) including a first catalytic bed (2) for removal of N2O followed by a second catalytic bed (3) for removal of NOx, wherein during a start-up or shutdown the operation of said treatment section (10) is temporarily modified by adding a NOx reducing agent (4) upstream of said first catalytic bed (2), so that said first catalytic bed (2) provides reduction of NOx.

The present disclosure provides a method of forming a selective catalytic reduction (SCR) catalyst, the method comprising receiving a first iron-promoted zeolite having a first iron content and treating the iron-promoted zeolite with additional iron in an ion exchange step to form a second iron-promoted zeolite having a second iron content, the second iron content being higher than the first iron content. Also provided herein is a selective catalytic reduction (SCR) catalyst composition comprising an iron-promoted zeolite having at least about 6 weight percent iron, based on the total weight of the iron-promoted zeolite, wherein the iron content of the zeolite is added to the zeolite in at least two separate steps.

The invention relates to a process for producing nitric acid comprising at least one step for treating a gaseous effluent containing N2O, said process comprising at least the following steps in this order: - a step in which ethanol is added to the gaseous effluent; - a step for treating the gaseous effluent which is a decomposition step of the N2O on a catalytic bed containing at least one catalyst comprising an iron-exchanged ferrierite zeolite, at a temperature below 400°C. The invention also relates to a nitric acid production unit.

Provided is a flue gas treatment device (100) configured to treat a flue gas from a combustion device (200) that combusts fuel containing ammonia, and the flue gas treatment device (100) includes: an ammonia decomposition unit (10) having an ammonia decomposition catalyst that decomposes ammonia contained in the flue gas; and a nitrogen oxide decomposition unit (20) having a second catalyst that decomposes nitrous oxide and NOx contained in the flue gas in which ammonia was decomposed by the ammonia decomposition unit (10).