21 results about "Selective catalytic oxidation" patented technology

The invention discloses a preparation method and application of an oligomeric vanadium (V)-based catalyst for preparing acetic acid through selective catalytic oxidation of ethyl acetate. A series of V-doped catalysts are prepared by taking an oxide as a carrier and V precursors with different masses through an impregnation method. The catalyst carrier comprises TiO2 (titanium dioxide), gamma-Al2O3 (aluminum oxide), SiO2 (silicon dioxide), CeO2 (cerium dioxide) and ZrO2 ( The mass range of the V element is 0.5 to 10.0 weight percent, preferably 2.0 weight percent. Precise regulation and control of different VOx aggregation state structures are realized by screening carriers and controlling V loading capacity. The catalyst is simple in preparation process and has good selective catalytic performance on ester VOCs (such as ethyl acetate), the conversion rate of ethyl acetate can reach 20% while the selectivity of acetic acid reaches up to 93%, and the catalyst can stably and continuously run for 300 h.

This invention belongs to the field of catalyst preparation technology, specifically disclosing a hydrotalcite-derived metal oxide catalyst, its preparation method, and its application. The preparation method includes the following steps: dissolving cobalt and aluminum metal salts in deionized water to obtain solution A; dissolving copper metal salt in deionized water to obtain solution B; preparing an alkaline precipitant solution C containing hydroxide and carbonate ions; under heating conditions, adding solution C dropwise to solution A while vigorously stirring, adjusting the pH to alkaline, obtaining a mixed solution; simultaneously titrating solution B and solution C together into the mixed solution, adjusting the pH to alkaline, aging the reaction, washing, drying, grinding, and calcining in an oxygen atmosphere to obtain the hydrotalcite-derived metal oxide catalyst. This hydrotalcite-derived metal oxide catalyst can promote the adsorption and conversion of NH3 and the generation of N2, showing good application prospects in the selective catalytic oxidation and degradation of NH3.

The invention discloses a manganese oxide material with surface defects as well as a preparation method and application thereof. The method comprises the following steps: soaking a manganese oxide in an ammonia water solution to obtain an ammonia-containing manganese oxide, placing the ammonia-containing manganese oxide in a fast heating tube furnace, and rapidly heating in a short time to vaporize, expand and escape ammonia to generate surface defects, thereby obtaining the manganese oxide with the surface defects. The manganese oxide material with the surface defects prepared by the method is simple and convenient in preparation method and controllable in preparation process, the prepared manganese oxide with the surface defects has excellent photo-thermal selective catalytic oxidation performance on ammonia gas, the performance of the manganese oxide material is obviously superior to that of a common photo-thermal catalytic material at present, and the manganese oxide material is applicable to purification of low-concentration ammonia gas.

Nuclear energy utilization is very important for our country's national defense construction and sustainable development of energy system, however, the safe disposal and reuse of a large number of depleted uranium produced after nuclear energy utilization is a problem to be solved in pollution prevention and control work. 238 U, which is harmless to human body), in particular, we use U3O8 prepared from depleted UF6 as raw material, and prepare beta-UO3 as catalyst by a simple dissolution and reprecipitation method, and the beta-UO3 is used for catalyzing oxidation of aniline to synthesize 1-oxidized diphenyldiazene or derivatives thereof; the application creates a way for reuse of depleted uranium waste, and on the other hand, aniline and its derivatives can be converted into 1-oxidized diphenyldiazene or derivatives thereof with higher added value, which has extremely important significance from the aspects of environmental friendliness and sustainable development, and from the aspect of synthesizing higher added value products.

The rational use of nuclear energy plays a vital role in the process of consolidating national defense and security and green transformation of energy system in China. However, the proper management and resource utilization of depleted uranium (especially 238 U, which does not pose a direct radiation threat to human body) generated from the application of nuclear energy have become a technical problem to be solved in the field of environmental protection and sustainable development. In particular, we use U3O8 prepared from depleted UF6 as raw material, and use UO4·2H2O prepared by simple dissolution and precipitation as catalyst to prepare 1-oxidized diphenyldiazene or its derivatives by catalytic oxidation of aniline. On the one hand, the invention creates a way to reuse depleted uranium waste, and finds a new way to transform this traditionally regarded as a problem waste, on the other hand, it ingeniously builds a bridge from aniline and its derivatives to high value-added chemicals-1-oxidized diphenyldiazene or its derivatives, which shows extraordinary value in environmental, economic and social benefits. Whether from the perspective of environmental friendliness and sustainable development, or from the perspective of synthesizing higher value-added products, it has extremely important significance.

The application provides a defective silver-based catalyst and a preparation method and application thereof, and belongs to the technical field of ammonia treatment. The preparation method of the defective silver-based catalyst provided by the application comprises the following steps: first calcining H-ZSM-5 zeolite molecular sieve to obtain pretreated molecular sieve; mixing the pretreated molecular sieve with a tetrapropylammonium hydroxide solution, and performing hydrothermal reaction to obtain a molecular sieve precursor; second calcining the molecular sieve precursor to obtain a defective molecular sieve; mixing the defective molecular sieve with a soluble silver salt solution, and performing impregnation treatment to obtain a catalyst precursor; third calcining the catalyst precursor to obtain a defective silver-based catalyst. The defective silver-based catalyst prepared by the application has high catalytic performance and high stability in the reaction of selective catalytic oxidation of ammonia.

The application discloses a tail gas aftertreatment device, which comprises a selective catalytic oxidizer, a particle trap, a mixer and a selective catalytic reducer arranged in sequence along an axial direction, wherein the mixer comprises a mixing cylinder and a flow guide plate, and an inside of the mixing cylinder is formed with a mixing cavity; a rear air inlet part of the mixing cylinder is inwardly recessed, two sides of the rear air inlet part are symmetrical arc-shaped cylinder walls, the rear air inlet part is provided with a rear air inlet hole, and the two arc-shaped cylinder walls are respectively provided with a left air inlet hole and a right air inlet hole; the flow guide plate is arc-shaped and located at a rear side of the rear air inlet hole, and an arc-shaped channel is formed between the flow guide plate and the mixing cylinder and leads to the left air inlet hole, the right air inlet hole and the rear air inlet hole from a front side. The device can make the reducing agent and the exhaust gas fully mix, evaporate and decompose, and improve the mixing uniformity and the anti-crystallization performance.

The invention discloses a method for preparing waste grease-based vegetable insulating oil through manganese catalytic oxidation decolorization, which comprises the following steps: by taking a complex formed by manganese salt and 2, 2 '-bipyridine derivative as a catalyst and taking a urea hydrogen peroxide compound as an oxidant, carrying out selective catalytic oxidation on pigment molecules in waste grease under mild conditions, thereby obtaining the waste grease-based vegetable insulating oil. The decolorization rate can reach 85%-92%; a small amount of activated clay is subsequently used for adsorbing and removing the residual metal catalyst and trace oxidation byproducts, and the high-quality vegetable insulating oil with various physicochemical indexes meeting the requirements can be obtained. The use amount of the urea hydrogen peroxide compound used in the method is small, compared with direct use of high-concentration hydrogen peroxide, the stability is higher, the oxidability is milder and more controllable, and the problems of grease emulsification, acid value increase, non-selective oxidation and the like caused by excessive hydrogen peroxide are effectively avoided. The method is mild in reaction condition, high in selectivity, low in catalyst and auxiliary material consumption and suitable for industrial production of the high-quality vegetable insulating oil.

The invention is applicable to the technical field of heat supply systems, and provides a heat supply system based on a safe hydrogen-based energy selective catalytic oxidation technology, which comprises a reaction module, a heat supply module and a separation module, the reaction module is used for inputting safe hydrogen-based energy and oxygen-containing gas and carrying out selective catalytic oxidation reaction under the action of a catalyst; the heat supply module is connected with the reaction module, absorbs heat of the reaction module through a heat exchange medium and conveys the heat to a heat supply end; and the separation module is also connected with the reaction module and is used for separating the reacted gas-liquid mixture, recovering a dehydrogenation product, water and treating waste liquid. The heat supply system is safe, green, controllable and sustainable, raw materials are ensured to be recycled, the cost is reduced, and heat supply is stable.

This invention provides a small-scale selective oxidation sulfur recovery device and method. The device includes: a main combustion furnace, a steam generator, a sulfur condenser, a heater, a Claus reactor, a selective catalytic oxidation reactor, and a blower connected in sequence. The blower is connected to main regulating air and fine-tuning air pipelines. A fixed amount of air supplied by the blower through the main regulating air pipeline is mixed with acidic gas containing H2S and enters the main combustion furnace for combustion to generate high-temperature process gas. After recovering liquid sulfur through the steam generator and sulfur condenser, the process gas is heated by the heater and sent to the Claus reactor to undergo a Claus reaction. The produced process gas is mixed with a fixed amount of air supplied by the fine-tuning air pipeline and undergoes a selective oxidation reaction of H2S in the selective catalytic oxidation reactor. The produced process gas is then recovered as liquid sulfur through the sulfur condenser. This simplifies the process flow and reduces the required equipment investment while ensuring sulfur recovery output, thus improving the economic efficiency of small-scale sulfur recovery production.

The invention provides a selective oxidation-based liquid ammonia impurity removal method and system. The method comprises the following steps: acquiring impurity composition data of to-be-treated liquid ammonia to determine a catalyst type, an oxygen content control range and a reaction temperature required by the selective oxidation process of the liquid ammonia; based on the catalyst type and the oxygen content control range, establishing a selective oxidation reaction zone corresponding to the pretreated liquid ammonia in the reactor; setting an oxygen content control value of the selective oxidation reaction zone in the oxygen content control range, controlling the reaction temperature, and carrying out selective catalytic oxidation reaction on the pretreated liquid ammonia in the selective oxidation reaction zone; and carrying out gas-liquid separation on the reacted mixed product to obtain target liquid ammonia. According to the scheme, non-selective oxidation of the liquid ammonia body can be inhibited to the maximum extent, efficient removal of impurities is achieved, and energy conservation and environmental protection are achieved.

The present application relates to a kind of bimetallic synergistic molecular sieve catalyst, preparation method and its application, the molecular sieve catalyst includes molecular sieve carrier and active component;Molecular sieve carrier includes SSZ-13 molecular sieve;Active component includes Cu and Ru;Cu is in the form of single atom distribution in the CHA cage of molecular sieve carrier;Ru is in the form of RuO2 nanoparticle distribution on the surface of molecular sieve carrier.The bimetallic synergistic molecular sieve catalyst provided by the present application, Cu and Ru and the bimetallic synergistic effect between them can significantly improve the catalytic performance of the molecular sieve catalyst, so that NH3 selective catalytic oxidation reaction has higher NH3 conversion rate in the temperature range of 150~200 ℃, and in the temperature range of 200~300 ℃, NH3 conversion rate is close to 100%, while in the wide temperature range of 150~300 ℃, always maintain high N2 selectivity.

The invention discloses a silver-copper composite catalyst for selective catalytic oxidation of ammonia as well as a preparation method and application of the silver-copper composite catalyst. According to the catalyst, CeO2 serves as a carrier, silver (Ag) and copper (Cu) serve as active components, the molar ratio of Ag to Cu ranges from 1: 2 to 2: 1, and the total metal loading amount ranges from 1 wt% to 5 wt%. According to the invention, active components Ag and Cu are compounded to generate a remarkable synergistic effect, and compared with a single metal Ag / CeO2 or Cu / CeO2 catalyst, the AgCu / CeO2 catalyst shows lower ignition temperature, higher NH3 conversion rate, higher N2 selectivity and lower preparation cost in NH3-SCO reaction. The catalyst is simple in preparation method and suitable for treating ammonia-containing waste gas generated by a fixed source or a moving source.

The invention relates to a biomass charcoal-based non-noble metal catalyst for oxidation of 5-hydroxymethylfurfural and a preparation method of the biomass charcoal-based non-noble metal catalyst. The catalyst is obtained by loading cobalt and other transition metals (manganese, nickel, iron or zinc) by lignin through an impregnation-calcination method. The preparation method of the catalyst is simple, the cost of raw materials is low, and the catalyst has high catalytic activity and selectivity when being used for generating 2, 5-furandicarboxylic acid through selective catalytic oxidation of 5-hydroxymethylfurfural under mild conditions. Moreover, by controlling the loading capacity and the loading type of the transition metal, a multi-site synergistic effect is realized, and the catalytic performance of the catalyst can be effectively improved.

The application discloses a noble metal catalyst for selective catalytic oxidative dehydrogenation of crude helium, which comprises an active component, a carrier, an auxiliary agent and a selective regulator; the active component is selected from one or two of Pt, Pd and Ru; the carrier is alumina pellets prepared with the aid of ammonium alginate; the auxiliary agent is any one or more of Ce, La, Y, Zr, Mg and Sr; and the selective regulator is selected from one or more of Ni, Mn, Co, Mo, W and Nb. The catalyst can be applied to a catalytic oxidative dehydrogenation unit for helium extraction from natural gas, realizes selective oxidation of hydrogen, and solves the problem that the existing catalyst simultaneously catalytically oxidizes methane in crude helium into CO2. Through modification of the catalyst, adsorption of methane is inhibited, CO2 generation is greatly reduced, and the load of a subsequent separation and purification unit is reduced. The catalyst has good low-temperature activity, low CO2 selectivity, and the volume fraction of H2 in outlet gas after dehydrogenation is lower than 0.1 ppm, and the volume fraction of CO2 is lower than 30 ppm.

This invention discloses a method for the photoenzymatic selective catalytic oxidation of inactive C-H bonds in polysaccharides, belonging to the field of photoenzyme-coupled catalysis technology. This invention employs a photocatalyst that enhances visible light absorption and efficiently generates electrons and H2O2, continuously and gently providing the necessary electrons and co-substrate for the LPMO reaction under illumination. Furthermore, by introducing a dopamine functional layer onto the catalyst surface, LPMO is enriched on the catalyst surface, forming a proximity effect that effectively improves the transfer efficiency of electrons and H2O2 from the photocatalyst to the LPMO, significantly enhancing the catalytic activity of the LPMO and achieving efficient oxidation of inactive C-H bonds in polysaccharides. Compared with traditional systems that require continuous replenishment of exogenous electron donors and H2O2, this invention is simpler to operate, lower in cost, and can be further extended to other peroxidase systems that rely on electron donors and H2O2. Overall, it has green, low-carbon, high-efficiency characteristics and promising prospects for industrial application.

A method for preparing a copper-based NH3 oxidation and purification catalyst using atomic layer deposition (ALD) technology is disclosed, relating to the field of environmental catalysis. Using mesoporous materials such as Al / SBA-15 as supports, copper is loaded as the active component via ALD to obtain the catalyst. The resulting catalyst exhibits extremely high specific surface area and uniform pore size distribution, which is beneficial for the dispersion of copper active species and greatly optimizes the mass transfer and diffusion between reactants and products. This catalyst is applied to the selective catalytic oxidation of ammonia, utilizing its unique copper species ([Cu-O-Cu)). 2+ This effectively prevents ammonia from being over-oxidized at high temperatures, thus improving the N2 selectivity of the target product. The catalyst disclosed in this invention achieves 100% NH3 conversion and over 90% N2 yield within a temperature range of 350-400℃.

This invention discloses a heterogeneous nanostructure photocatalyst, its preparation method, and its application. The invention modifies the surface of the g-C3N4 photocatalyst by introducing carbon quantum dots (CDs) through doping technology. The CDs / g-C3N4 composite photocatalyst abandons conventional metal catalysis, and its preparation process is simple, low-cost, and reusable without deactivation, making it a promising new composite photocatalyst in the field of visible light catalytic oxidation technology. Applying this catalyst to the visible light selective catalytic oxidation synthesis of the key intermediate 3-(4-nitro-1-oxo-1,3-dihydro-2H-isoindol-2-yl)piperidine-2,6-dione demonstrates good yields.

The invention provides a composite catalyst and application thereof in preparation of ammonium sulfate through low-temperature oxidation, and belongs to the technical field of energy conservation, environmental protection and resource recycling. The catalyst takes an HZSM-5 molecular sieve as a carrier, MnO2, Co3O4 and CeO2 are loaded, Mn and Co form a Mn-Co solid solution structure, and CeO2 exists on the surface of the Mn-Co solid solution in an interface enrichment form. The molar ratio of Mn to Co is 1.70-1.90, the content of MnO2 is 5.0-8.0 wt%, the content of Co3O4 is 3.0-4.5 wt%, and the content of CeO2 is 1.0-2.5 wt%. The catalyst can efficiently and selectively catalyze and oxidize SO2 and NH3 at 80-150 DEG C under normal pressure to generate ammonium sulfate, the conversion rate of SO2 at 120 DEG C is greater than or equal to 90%, the selectivity of ammonium sulfate is greater than or equal to 94%, and the activity is maintained to be greater than or equal to 90% after continuous operation for 1000 hours. The method breaks through the limitation of the traditional high-temperature process, obviously reduces the energy consumption, realizes the resource utilization of the sulfur-containing waste gas, and has excellent industrial application value.

The application relates to the field of selective catalytic oxidation, and relates to an NH3-SCO core-shell catalyst and synthesis and application thereof, and comprises the following steps: S1: catalyst core material preparation: preparing a metal precursor solution as a catalyst core material, adding a pore-forming agent, heating, and then placing in an oven for drying, grinding, and calcining to obtain a powder-shaped precursor as the catalyst core material; S2: dispersing the precursor obtained in S1 in an organic solvent, sequentially adding a template agent, tetrabutyl titanate as a shell material, and a precipitating agent, stirring, filtering, washing, drying, grinding, and calcining to obtain the core-shell catalyst. Compared with the prior art, the application adjusts the dosage ratio of the core-shell material, adjusts the thickness of the shell, and then improves the catalytic efficiency and selectivity of the catalyst, and realizes efficient removal of ammonia-containing waste gas by the catalyst.

The application belongs to the technical field of organic synthesis, and particularly relates to selective oxidation of thioether to prepare sulfoxide and sulfone by using zirconium hydroxide as a catalyst. The application uses thioether as raw material, zirconium hydroxide as catalyst, and hydrogen peroxide as oxidant. Sulfoxide can be catalytically oxidized and synthesized in a short reaction time, and sulfone can be obtained by prolonging the reaction time. The selectivity can be regulated only by the reaction time without any additives. The zirconium hydroxide catalyst can be directly purchased or prepared by using a simple precipitation method with zirconium salt as a precursor, and is low in price. Hydrogen peroxide is used as an oxidant, and is green, stable, low in cost, high in atomic efficiency (47% active oxygen), and has water as the only by-product. In addition, the reaction process is simple in operation, low in cost, and high in yield, and has great industrial application prospect.