66 results about "Catalyst selectivity" patented technology

The invention belongs to the technical field of chemical catalysis, and particularly relates to a preparation method of an alkali metal cation modified cobalt-nitrogen-carbon monatomic catalyst and application of the catalyst in electrosynthesis of hydrogen peroxide. The Co-N-C / X catalyst is obtained by taking a cobalt-containing compound as a metal source, mixing the metal source with a nitrogen-containing organic matter and a carbon material, performing rotary evaporation, grinding and high-temperature pyrolysis in an inert atmosphere, performing acid washing with strong acid to construct surface defects, and finally performing stirring adsorption with an alkali metal salt solution, suction filtration and drying. Alkali metal cations are physically adsorbed and anchored on the surface and interface of the Co-N-C catalyst instead of being dissolved in a solution, so that the electronic structure of Co active sites and the adsorption energy of the * OOH intermediate are optimized, and the problem of separation of alkali metal and a product is solved. When the catalyst is used for electro-catalytic oxygen reduction reaction, the H2O2 selectivity reaches up to 98%, the preparation process is simple, the cost is low, large-scale production can be realized, and the problems that the traditional method is high in energy consumption and large in pollution and the existing catalyst is insufficient in selectivity are solved.

The invention discloses an enzyme catalysis preparation method of a milobalin intermediate. According to the method, racemization 3-ethyl bicyclo [3.2. 0] hept-3-ene-6-ketone is used as a substrate, specific ketoreductase is used as a catalyst, (1S, 5R)-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-ketone is selectively reduced into (1S, 5R)-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-alcohol, and a target compound milobalin intermediate (1R, 5S)-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-ketone is reserved. According to the method disclosed by the invention, only one enzyme is used, the concentration of a conversion substrate can reach 200g / L, the yield can reach 47.4%, the ee value can reach 99.8%, the operation is simple, the resolution efficiency is high, the selectivity is good, and the method can be used for industrial production.

A fixed adsorbent and catalyst bed containing system includes two or more first reactors in a reaction (RM) mode and two or more second reactors in a regeneration (RGM) mode that are sequentially operable and positioned in parallel. The two or more first reactors in the RM mode are configured to simultaneously in-situ decompose NH3 by a catalyst and selectively adsorb N2 by an adsorbent. At a substantially same time, the two or more second reactors in the RGM mode are configured to continuously regenerate the catalyst after decomposing the NH3 and the adsorbent after adsorbing the N2. A moving adsorbent bed and fixed catalyst bed containing system and a dual fluidized bed containing system are also provided. The present invention also relates to methods for decomposing ammonia (NH3) to nitrogen (N2) and hydrogen (H2).

The invention discloses a preparation method of liquid aliphatic secondary amine, which comprises the following steps: 1, carrying out reductive alkylation reaction on aliphatic secondary amine, 3, 3-dimethyl-2-butanone and hydrogen under the action of a platinum-carbon catalyst and a sulfur-containing organic matter; and 2, filtering the reaction mixture, and carrying out vacuum distillation to obtain the target product. According to the method, hydrogen is used as a reducing agent, the process is green and environment-friendly, side reactions are few, and the purity of the prepared aliphatic secondary amine can reach 98% or above. The preparation method comprises the following steps: dissolving trace dimethyl sulfoxide in an ethanol solution to form a dimethyl sulfoxide-ethanol dispersion mixed solution, adding the dimethyl sulfoxide-ethanol dispersion mixed solution into a high-pressure hydrogenation reaction kettle, fully mixing the dimethyl sulfoxide-ethanol dispersion mixed solution with an obtained imine mixture, and adding a platinum-carbon catalyst. The preparation method of the liquid aliphatic secondary amine, which is disclosed by the invention, has the advantages of high catalyst selectivity and strong activity, and is suitable for producing the liquid aliphatic secondary amine.

This invention relates to the field of SEBS preparation, specifically to a method for predicting the degree of hydrogenation of SEBS. The method utilizes the designed values ​​of the amount m of the main catalyst, the lithium / main catalyst molar ratio n, and the co-catalyst / main catalyst molar ratio X in the selective hydrogenation process of SBS gel polymerized by active lithium anion polymerization and the main catalyst and co-catalyst. Formulas 1 to 9 are then used to calculate and predict the degree of hydrogenation Y of the prepared SEBS. Formula 1: Y = 0.12 + 0.88 * X, Formula 2: Y = 0.19 + 0.81 * X, Formula 3: Y = 0.25 + 0.75 * X, Formula 4: Y = 0.17 + 0.83 * X, Formula 5: Y = 0.25 + 0.75 * X, Formula 6: Y = 0.31 + 0.69 * X, Formula 7: Y = 0.2 + 0.8 * X, Formula 8: Y = 0.32 + 0.68 * X, Formula 9: Y = 0.4 + 0.6 * X. This invention also includes a synthesis method for precisely controlling the degree of hydrogenation of SEBS using the aforementioned prediction method. The process described in this invention can predict the degree of hydrogenation of SEBS with high accuracy.

The preparation of high-value-added aromatic carboxylic acids via CO2 carboxylation coupling through activation of the benzyl C-H bond in alcohols / amines is a green and sustainable pathway to achieve CO2 resource utilization and contribute to carbon neutrality. However, this field currently faces challenges such as poor catalyst selectivity, low CO2 activation efficiency, and a narrow substrate applicability range, making it difficult to meet practical application needs. To address this issue, this patent discovers that in a heterogeneous electrocatalytic system, cuprous selenide (V2), rich in selenium vacancies, can be used... Se -Cu 2‑x Using Se as the core catalyst, it can not only efficiently promote the synergistic activation of benzyl C-H bonds and CO2 carboxylation, significantly improving the overall catalytic activity of the reaction, but also achieve precise chemoselective carboxylation control for different types of substrates. Specifically, this V Se -Cu 2‑x Se electrocatalysts can efficiently and selectively activate the benzyl C-H bond in alcohols and subsequently induce CO2 carboxylation, exhibiting excellent chemoselectivity in the conversion of benzyl alcohol to mandelic acid and its derivatives. Simultaneously, they also demonstrate excellent catalytic performance for amines, selectively catalyzing the carboxylation of amine substrates such as benzylamine with CO2 to directionally generate phenylglycine and aromatic amine-derived carboxylates. Crucially, in addition to typical benzyl alcohol and benzylamine, the substrate applicability of this catalytic system can be extended to various alcohols and amine derivatives, realizing the carboxylation transformation from simple model substrates to diverse functional molecules, providing a new approach for the large-scale preparation of high-value-added aromatic carboxylates.

The application provides a synthesis method and application of a catalyst for preparing formaldehyde by oxidizing methanol, and belongs to the field of catalyst preparation. The iron-molybdenum catalyst containing an additive is synthesized in a micro-channel reactor, the catalyst has high utilization rate of metal elements, light density, uniform granularity, high catalytic stability, high forming strength and long service life. The catalyst is filled in a fixed bed and used for preparing formaldehyde by oxidizing methanol, so that the polymerization of the reaction is reduced, the selectivity of the catalyst is improved, the loss of active components is reduced, and the service life of the catalyst is prolonged. The synthesis process of the catalyst is simple, the catalyst has small and uniform particle size, no flaky impurity crystals, high utilization rate of metal elements, and plays a positive role in treating wastewater generated in the later catalyst production.

The invention relates to a ship tail gas hydrogen cyanide (HCN) purification catalyst and a preparation method and application thereof. The preparation method comprises the following steps: calcining TiO2 powder to remove surface impurities and stabilize a crystal form; the preparation method comprises the following steps: respectively dissolving active components in oxalic acid / citric acid solutions, and fully stirring and mixing all component solutions; immersing the TiO2 carrier into a mixed solution containing an active component precursor, and stirring; performing rotary evaporation to remove free moisture, and drying; and roasting the dried precursor in a muffle furnace to obtain the HCN selective oxidation catalyst. According to the scheme provided by the invention, the interaction among the active components can be greatly improved, the thermal stability is high, the dispersity is high, the agglomeration of the active components can be effectively reduced, and the performance is excellent. Meanwhile, the catalyst is high in selectivity, generation of greenhouse gas N2O can be reduced, no additional treatment device needs to be added, and the use cost is reduced.

The present invention discloses a Mg / Ba dual-doped catalyst for the catalytic combustion of methane, its preparation method, and application. The catalyst uses La2Ce2O7 as a carrier and Mg and Ba oxides as active components. The carrier and active components are combined using a hydrothermal method, and the catalyst is then uniformly loaded using a colloidal crystal template method. This pyrochlore-type compound (A2B2O7) has high thermal stability, meeting the requirements of a methane oxidative coupling (OCM) catalyst. The catalyst is highly selective, exhibits high catalytic activity in the OCM reaction at low temperatures (<650°C), exhibits high methane removal rates, and produces high yields of C2 products (C2H4 and C2H6), promising broad market applications.

The present invention discloses a highly stable Fischer-Tropsch synthesis iron-based catalyst and its use. The Fischer-Tropsch synthesis iron-based catalyst disclosed in the present invention is a catalyst with surface carbon modification, comprising a co-precipitated or impregnated catalyst of the Fe / Cu / K / Si or Fe / Mn / K / Si series and a carbonized layer coated on the SiO2 surface of the co-precipitated or impregnated catalyst. In the present invention, organic groups are introduced onto the surface of the catalyst silica by an organosilane reagent, and the organic groups are carbonized under appropriate calcination conditions to form a carbonized layer on the surface of the catalyst silica and at the iron-silica phase interface, inhibiting the transformation of iron carbide to Fe3O4 during the reaction process, inhibiting the CO2 selectivity of the catalyst, and simultaneously improving the reaction activity and long-term stability of the catalyst.

The invention discloses a catalyst selectivity descriptor analysis method and device based on average force potential, and relates to the technical field of catalyst performance prediction.The method comprises the steps that according to a catalytic reaction research target and literature, a catalyst molecular structure, selectivity determination steps and actual operation conditions are determined; obtaining an initial structure of a catalyst-substrate complex through conformation search; selecting reaction coordinates based on the chemical reaction characteristics of the set chemical reaction steps; based on the initial structure, determining state values of the reaction coordinates in the initial and final states of the reaction; calculating to obtain an average force potential through an umbrella-shaped sampling strategy and a multi-histogram strategy; extracting a reactant potential well position, potential well energy and a product potential well position from the average force potential, and determining a reaction path connecting the two potential wells; energy barrier differences are obtained through calculation; and based on the energy barrier difference, a catalyst selectivity prediction model is constructed according to the Kramers theory. Accurate prediction of the catalyst selectivity can be realized, and the research and development cost is reduced.

The invention belongs to the technical field of petrochemical catalysis, and relates to a combined modification method of titanium silicalite TS-1. The method comprises the following steps: 1, carrying out hydrothermal modification treatment on a TS-1 zeolite matrix by using a tetrapropylammonium hydroxide aqueous solution containing organic amine; the used organic amine has coordination and complexation effects on a TS-1 zeolite framework titanium center, so that the hydrothermal modification can adjust the framework titanium coordination state of the TS-1 zeolite, an open mononuclear hexa-coordination titanium catalytic active center is generated, and the catalyst activity is improved. And 2, carrying out solid zinc ion exchange treatment on the hydrothermally modified TS-1 zeolite catalyst by using zinc acetate dihydrate. The ion exchange treatment can adjust the microenvironment of open type mononuclear hexa-coordinated titanium species, eliminate acidic silicon hydroxyl around the microenvironment, and improve the selectivity of the catalyst. Zinc ions instead of alkali metal ions are introduced into the TS-1 zeolite through solid ion exchange treatment, so that the service life of the catalyst is prolonged.

The invention belongs to the technical field of petrochemical catalysis, and relates to a method for preparing a propylene liquid-phase epoxidized TS-1 zeolite catalyst. The method comprises the following steps: 1, carrying out hydrothermal modification treatment on a TS-1 zeolite matrix by using a tetrapropylammonium hydroxide aqueous solution containing isopropanolamine; the isopropanolamine has coordination and complexation effects on a TS-1 zeolite framework titanium center, so that the hydrothermal modification can adjust the framework titanium coordination state of the TS-1 zeolite, an open mononuclear hexa-coordination titanium catalytic active center is generated, and the activity of the catalyst is improved. And 2, carrying out solid zinc ion exchange treatment on the hydrothermally modified TS-1 zeolite catalyst by using a fusible zinc salt. The ion exchange treatment can adjust the microenvironment of open type mononuclear hexa-coordinated titanium species, eliminate acidic silicon hydroxyl around the microenvironment, and improve the selectivity of the catalyst. Zinc ions instead of alkali metal ions are introduced into the TS-1 zeolite through solid ion exchange treatment, so that the service life of the catalyst is prolonged.

The invention relates to the field of synthesis and preparation of hydroquinone, in particular to a synthesis method of high-purity hydroquinone. In order to solve the problem that in the existing process of preparing hydroquinone through a phenol hydrogen peroxide oxidation method, the selectivity of hydroquinone (HQ) is improved, and by-products with similar microstructures are generated synergistically and are difficult to remove, a composite catalysis synergistic inhibition system of phosphotungstic acid, tetrabutylammonium bromide and imidazole is adopted; through the synergistic effect of the main catalyst, the selectivity regulator and the byproduct inhibitor, HQ selectivity improvement and synchronous inhibition of trace byproducts are achieved under the optimized reaction condition, the total content of the trace byproducts is smaller than or equal to 45 ppm, the purity of the final hydroquinone product is larger than or equal to 99.995%, and the high-end application requirements of electronic-grade and photoresist raw materials are met. The technology is compatible with existing industrial equipment, operation is easy, and industrial production is met.

The application discloses a kind of squalene continuous flow catalytic hydrogenation squalane application alumina ball load palladium catalyst and its preparation method, the catalyst with gamma-alumina ball as carrier, modification impregnation method load palladium active component, with auxiliary control interface effect, form high dispersion Pd / Al2O3 Catalytic system, palladium loading is 0.01wt%-5wt%.The catalyst is filled in fixed bed reactor, and is applied to squalene continuous flow hydrogenation preparation squalane reaction, using continuous flow hydrogenation process, under mild conditions, squalene can be realized efficient conversion, conversion rate is ≥99%, squalane selectivity is ≥99%.The present application solves the problems of low selectivity, low utilization rate of noble metal and poor stability of existing squalene hydrogenation catalyst, and the problems of low efficiency and difficult industrial continuous production of traditional batch hydrogenation process.The process conditions are mild, environmentally friendly and suitable for industrial application.Compared with traditional Pd / C catalyst, the catalyst has higher activity and stability.

The invention belongs to the technical field of synthesis of epoxy compounds, and discloses a preparation method of (methyl) epichlorohydrin. The preparation method comprises the following steps: (1) after tungstic acid reacts with hydrogen peroxide A, adding phosphoric acid for continuous reaction to prepare peroxyphosphotungstic acid; and (2) mixing the peroxy phosphotungstic acid prepared in the step (1) with allyl chloride or methyl allyl chloride dissolved with quaternary ammonium salt and a pH regulator, and adding hydrogen peroxide B for reaction to prepare epoxy chloropropane or methyl epoxy chloropropane. By adopting the preparation method provided by the invention to prepare the (methyl) epichlorohydrin, the procedures of liquid separation, drying and the like in the catalyst preparation process are omitted, the process steps are few, and hydrogen peroxide and a large amount of solvent can be saved while the process is simplified; and the prepared catalyst is high in selectivity, good in reuse effect and convenient to recycle and reuse.

The application belongs to the technical field of chemical catalysis, and particularly relates to a preparation method of an alkali metal cation modified cobalt-nitrogen-carbon single-atom catalyst and an application of the catalyst in electro-synthesizing hydrogen peroxide. A cobalt-containing compound is used as a metal source, mixed with a nitrogen-containing organic matter and carbon material, and then subjected to rotary evaporation, grinding, inert atmosphere high-temperature pyrolysis, and finally, surface defect construction through strong acid pickling. Finally, the Co-N-C / X catalyst is obtained through stirring adsorption of an alkali metal salt solution, suction filtration and drying. In the application, the alkali metal cation is physically adsorbed and anchored on the surface interface of the Co-N-C catalyst, rather than being dissolved in the solution, which not only optimizes the electronic structure of the Co active site and the adsorption energy of the OOH intermediate, but also avoids the difficulty in separating the alkali metal from the product. When the catalyst is used in the electro-catalytic oxygen reduction reaction, the selectivity of H2O2 is as high as 98%, and the preparation process is simple, low in cost and scalable, thereby solving the problems of high energy consumption, serious pollution and insufficient selectivity of existing catalysts in the traditional method.

The invention relates to the technical field of catalyst preparation, in particular to a method and a system for preparing a catalyst for preparing glycollic acid through efficient electrocatalytic oxidation of PET (polyethylene terephthalate). The method comprises the following steps: ultrasonically cleaning foamed nickel to obtain ultrasonically cleaned foamed nickel, preparing a hydrothermal solution, performing hydrothermal reaction on the hydrothermal solution to obtain an initial intermediate, and cleaning and drying the initial intermediate to obtain the catalyst for preparing glycollic acid through efficient electrocatalytic oxidation of PET. The method comprises the following steps: obtaining an intermediate, shearing an intermediate sheet, preparing an electro-deposition liquid, constructing a three-electrode system, depositing a working electrode to obtain deposited Pd particles, slowly flushing the deposited Pd particles to obtain clean deposited Pd particles, testing the catalyst by a linear voltammetry scanning method to obtain the catalytic activity of the catalyst, and performing a chronoamperometric test on the catalyst to obtain the catalytic activity of the catalyst. The selectivity test is performed on the catalyst, so that the selectivity of the catalyst is excellent, and the preparation of the catalyst for preparing glycollic acid through high-efficiency electrocatalytic oxidation of PET is completed. The use amount of precious metal can be reduced on the premise of ensuring the catalytic performance.

Acrolein is produced by selectively oxidizing iso-propanol over a first mixed metal oxide catalyst in the presence of oxygen in the vapor phase. The first mixed metal oxide catalyst comprises oxides of molybdenum and bismuth. Acrylic acid is produced by selectively oxidizing the acrolein over a second mixed metal oxide catalyst in the presence of oxygen in the vapor phase. The second mixed metal oxide catalyst has a different composition from the first mixed metal oxide catalyst.

The invention discloses vinyl silicone oil and a preparation method thereof, and belongs to the technical field of organic silicon materials. The preparation method comprises the following steps: carrying out vacuum molecular distillation and purification on raw materials, preparing a bidentate carboxylate ligand from hydroxyl-carboxyl bidentate substituted aromatic acid, carrying out ion exchange on the bidentate carboxylate ligand and P5 < + > Cl <-> to prepare a P5 < + >-L catalyst, finally catalyzing ring-opening copolymerization of D4, D4Vi and an end-capping reagent, and carrying out glacial acetic acid quenching, stepped vacuum devolatilization and filtration to obtain the product. The product is applied to the fields of high-end electronics, medical use and the like. In order to overcome the defects of poor catalyst selectivity, non-uniform vinyl distribution and high residue in the prior art, the invention provides a bidentate ligand phosphazene salt catalytic system, realizes selective polymerization of monomers through the synergistic effect of bidentate coordination and zwitterions, solves the problems of continuous blocks of MeViSiO units, metal residues and excessive volatile impurities, and improves the yield of the catalyst. The product is high in purity and stable in performance, and meets the requirements of high-end fields.

The invention belongs to the technical field of petrochemical catalysis, and relates to a method for propylene liquid phase epoxidation on a zinc modified TS-1 zeolite catalyst. The zinc modified TS-1 zeolite catalyst is prepared by a combined modification method, and the method comprises the following steps: 1, carrying out hydrothermal modification treatment on a TS-1 zeolite matrix by using a tetrapropylammonium hydroxide aqueous solution containing isopropanolamine, adjusting the coordination state of TS-1 zeolite skeleton titanium, generating an open mononuclear hexa-coordination titanium catalytic active center, and improving the activity of the catalyst; in the second step, the microenvironment of the open type mononuclear hexa-coordinated titanium species is adjusted by using the fusible zinc salt, so that acidic silicon hydroxyl around the microenvironment is eliminated, and the selectivity of the catalyst is improved; the propylene liquid phase epoxidation method is technically characterized in that hydrogen peroxide with the concentration lower than 50 wt.% is used as an oxidizing agent on the catalyst to produce epoxypropane, and a gas-solid phase oxidation method is used for regenerating the deactivated catalyst.

This invention discloses a catalyst for the synthesis of chlorobenzene and its application, belonging to the field of catalyst technology. The catalyst is a CeO2@volcanic rock composite material supported on FeCl3 / ZnCl2. This invention uses ferric chloride and zinc chloride, two Lewis acids, as the main catalytically active components, and the CeO2@volcanic rock composite material as the support, loading the catalytically active components via an impregnation method. In the catalyst prepared by this invention, the support structure is optimized through the CeO2 and volcanic rock composite material, allowing ferric chloride and zinc chloride to be highly dispersed and anchored on the support, thus improving catalytic efficiency. The co-loading of ferric chloride and zinc chloride adjusts the acid strength of the Lewis acid, meeting the requirements for activating chlorine gas to generate chlorobenzene, while avoiding secondary substitution, significantly improving catalyst selectivity.

The application discloses a method for continuously synthesizing alpha-acetyl-gamma-butyrolactone, which comprises the following steps: vaporizing 1,4-butanediol and then feeding the vaporized 1,4-butanediol into a first fixed-bed reactor filled with a nano copper oxide catalyst doped with Mn, Al, Yb, Sr and Cr to perform a reaction, so as to obtain gamma-butyrolactone gas; continuously feeding the gamma-butyrolactone gas, vaporized acetic anhydride and nitrogen into a second fixed-bed reactor filled with a silver-modified graphene / SiO2 composite catalyst under the protection of nitrogen to perform a reaction, and then performing rectification on a product obtained through multi-stage condensation, so as to obtain a target product. The method provided by the application has stable reaction conditions, high selectivity and specificity of a catalyst and high yield, and can realize continuous production of the product.

The invention discloses a preparation method of a catalyst for preparing acrolein through propylene oxidation, and relates to the technical field of acrolein catalytic synthesis. Ammonium molybdate, potassium nitrate and a crystal growth modifier are prepared into a mixed solution A; preparing bismuth nitrate and an acidic reagent into an acidic bismuth nitrate solution, and further mixing the acidic bismuth nitrate solution with the metal salt solution containing iron, cobalt and nickel to obtain a mixed solution B; carrying out precipitation reaction on the mixed solution A, the mixed solution B and a precipitator in a supergravity reactor, and obtaining precursor slurry after the reaction is completed; carrying out hydrothermal treatment on the precursor slurry, washing, drying, calcining, mixing with a carrier and an auxiliary agent, tabletting, and carrying out secondary calcining to obtain the catalyst. According to the preparation method of the acrolein catalyst, the catalyst prepared by using the crystal growth modifier and the choline hydroxide precipitator in combination with the supergravity coupling hydrothermal reaction has a relatively high active crystal face exposure proportion and relatively good catalyst selectivity.

The invention is suitable for the technical field of nucleotide synthesis, and provides a high-efficiency green synthesis method of 3 '-amino nucleotide, which is green and environment-friendly, and efficiently adapts to industrial production. Pure water is used as a unique solvent, so that no harmful waste is discharged; 5% of the Pd / C catalyst can be recycled, the low-concentration TEAB eluent can be recycled, and the green chemistry concept is met. The Pd / C catalyst has the advantages of high selectivity, few side reactions (impurities are less than or equal to 5%), mild reaction conditions (normal-pressure hydrogen and 50 DEG C), time consumption of only 2 hours and raw material conversion rate of more than or equal to 99%. DEAE resin and low-concentration gradient elution purification are adopted, the HPLC purity of the product is larger than or equal to 95% (part is larger than or equal to 98%), and the molar yield is 46-85% and is superior to that of an existing method; only two-step core operation is adopted, post-treatment is simple and convenient, corrosion to equipment is small, the method can adapt to 3 '-azido nucleotide raw materials with various substituent groups, and the preparation requirements of different drug intermediates are met.

The present invention relates to a magnetic ceramsite catalyst loaded with heteropolyacid and a preparation method of sec-butyl acetate. The preparation method of sec-butyl acetate comprises: preheating a carbon four fraction after etherification and glacial acetic acid to 90-100 degrees Celsius respectively, controlling the space velocity of the carbon four fraction after etherification to be 1.0-2.0h ‑1 The invention relates to a process for preparing a esterification reaction vessel comprising a first step of preparing a first esterification reaction vessel and a second step of preparing a second esterification reaction vessel. The first step is to prepare a first ... esterification reaction vessel and a second esterification reaction vessel.

A process for producing ammonia from natural gas and air consists in purifying natural gas of sulphurous impurities by catalytic hydrotreatment and the chemical adsorption of hydrogen sulphide, heating the purified natural gas, subjecting same to primary and secondary reforming and subsequently converting carbon monoxide into carbon dioxide. The obtained synthesis gas is purified of carbon dioxide then subjected to methanation, adsorption drying and low-temperature rectification, followed by the synthesis of liquefied ammonia. Process media are heated by differential cooling of the flue gases from a primary reforming furnace, and high-pressure steam is generated by heat from secondary reforming. A spent synthesis gas line between the methanation and ammonia synthesis stages is supplemented with adsorption drying and low-temperature rectification. The flue gases from the primary reforming furnace are selectively purified of nitrogen oxides using catalysts based on oxides of vanadium, titanium, tungsten or aluminium. The process line is duplicated. The technical result is that of reducing the use of fuel-grade natural gas, reducing the environmental impact on the surroundings and reducing the risk of the emergency shutdown of ammonia production.

The invention regards a computer-implemented method for optimizing ethylene oxide catalyst selectivity and activity in an ethylene oxide reactor system by use of a digital twin configured to simulate the operation of the ethylene oxide reactor system, said method comprising comprising: collecting real time process data of the reactor system via a data collection module, cleaning and validating the collected real time data via an online data cleaning and data validation module to clean faulty data and outliers and also validate the accuracy of collected data based on mass, energy and component balance, predicting a reactor behavior of the ethylene oxide reactor system via a digital twin model module, which is an artificial intelligence module trained with historical process data of the ethylene oxide reactor system, performing a root-cause analysis for diagnosis of catalyst selectivity and activity deterioration in real time via a root-cause analysis module, based on the cleaned and validated data and the predicted reactor behavior, identifying the root cause of CO2 change and its impact on catalyst selectivity / activity based on the root-cause analysis, a chloride zone detection module of ethylene oxide reactor digital twin detecting the chloride zone of ethylene oxide catalyst in real time via a chloride zone detection module based on the predicted reactor behavior and logic of catalyst characteristics, predicting future process parameters via a prediction module based on the cleaned and validated data and the predicted reactor system behavior, optimizing the process parameters of the ethylene oxide reactor system via an optimization module on a real time basis, and outputting a recommendation for optimum process parameters via a recommendation module to create output recommendations for preventive and corrective action to achieve the optimum catalyst performance, a feedback step to track the real time feedback of the reactor system for past recommendations and to suggest any corrective actions to recommendation modules, and an auto retraining step to track the digital twin models predictive accuracy and to execute an online auto retraining with most recent data to update the models to ensure the digital twin model remains up-to-date and with high prediction accuracy all the time of catalyst life

The invention discloses a preparation method and application of a nickel-loaded copper oxide nanowire catalyst for low-concentration nitrate reduction, and aims to solve the problems of poor selectivity and low activity of a traditional nitrate electroreduction catalyst. A copper oxide nanowire precursor is synthesized by adopting a wet chemical method, and is converted into the nickel-loaded copper oxide nanowire by utilizing a cation exchange method. The catalyst obtained by the method realizes efficient electro-catalysis of nitrate reduction to synthesize ammonia, significantly improves the activity and stability of the reaction, and has good application prospects. The catalyst is low in raw material cost, simple in synthesis method and relatively high in cost benefit.

The invention discloses a transition metal nanoparticle embedded biomass-derived nitrogen-doped carbon electrocatalyst as well as a preparation method and application thereof, and belongs to the technical field of H2O2 preparation. The problems that a transition metal-carbon material catalyst is low in H2O2 selectivity, complex in preparation process and not environmentally friendly are solved. The preparation method of the electrocatalyst comprises the following steps: carrying out a hydrothermal reaction on a biomass fiber material and concentrated alkali liquor, then carrying out a hydrothermal reaction on obtained biomass cellulose, transition metal salt and an organic ligand to obtain a metal-loaded nitrogen-containing biomass carbon material, and carrying out heat treatment on the biomass carbon material to obtain the electrocatalyst. The electrocatalyst is used as a cathode to electrocatalyze two-electron oxygen reduction to synthesize H2O2. According to the invention, a nitrogen source easy to pyrolyze and oxidized fibers are coordinated and combined through hydro-thermal synthesis, and holes are etched and formed in the catalyst during high-temperature pyrolysis, so that the mesoporous content of the catalyst is increased; the catalyst has good ability of two-electron oxygen reduction electrosynthesis of H2O2, and the H2O2 selectivity and yield are high.