最新刊期
期 1 ， 2024
-
摘要：Heterogeneous catalytic hydrogenation is an important approach for preparation of high-value-added fuels and chemicals, while the processes of H2 heterolysis and chemical properties of generated hydrides (M—Hδ-) are closely related to hydrogenation activity and selectivity. However, the complex surface structure of heterogeneous catalysts, which leads to a diversity of H2 heterolysis process and M—Hδ- chemical properties, poses a great challenge in understanding the regulation of H2 heterolysis and M—Hδ- chemical properties on the mechanism of hydrogenation reactions. The mechanism of H2 heterolysis and the chemical properties of M—Hδ- were reviewed, and the characterization techniques commonly used to detect M—Hδ- were presented and their advantages and disadvantages were analyzed. The internal relationship between H2 heterolysis and the structure of active site of catalysts in different heterogeneous catalytic systems, such as metal-supported catalysts, metal oxide catalysts and anionic hybrid metal catalysts, as well as the optimization of the performance of hydrogenation reaction were discussed, and effective strategies to regulate H2 heterolysis were proposed. Finally, the main challenges in the study of H2 heterolysis and M—Hδ- were summarized and future development directions were outlined.关键词：hydrogenation reaction;H2 heterolysis;hydride;catalyst;heterogeneous catalysis- 20
- |
- 2
- |
- 0
发布时间：2024-01-26 -
摘要：To break through the “neck jamming” technology of iron-molybdenum formaldehyde catalysts and realize its localization and widespread application, the research progress of industrial application, laboratory preparation, reaction and deactivation mechanism of iron-molybdenum formaldehyde catalysts at home and abroad was reviewed. It is found that foreign iron-molybdenum formaldehyde catalysts achieve a formaldehyde yield of 93.3% after 70 years of industrial application and improvement, while domestic catalysts don’t realize large-scale import substitution yet after industrial trials. Co-precipitation method is the mainstream method for preparing the catalyst, and the structure and performance of the catalyst will be affected by n(Mo):n(Fe), additives, precipitation temperature, pH value, stirring speed, aging time and calcination temperature. The reaction of methanol oxidation to formaldehyde on the catalyst followed redox mechanism, in which lattice oxygen plays a role of oxidizing active site, and the rate-determining step of the reaction is may be methoxy generation, methoxy dehydrogenation, or lattice oxygen transfer process, and the loss of molybdenum volatilization during reaction is an important reason for catalyst deactivation. It is pointed out that it’s necessary at home to strengthen the research on iron-molybdenum formaldehyde catalysts formation mechanism, the influence law of preparation process on structure and performance of the catalyst, and the catalytic reaction and deactivation mechanism aimed at issues arising from industrial trials, so as to improve the catalyst performance, especially the catalyst stability.关键词：catalyst;iron-molybdenum process;formaldehyde;methanol oxidation- 20
- |
- 3
- |
- 0
发布时间：2024-01-26 -
摘要：Direct conversion of syngas to C2+ alcohols (alcohols with two or more carbon atoms) is currently one of the most promising routes for the synthesis of alcohols, and perovskite-structured catalysts can be used to improve the performance for the synthesis of C2+ alcohols in this process. Co and Mn doped perovskite LFC and LFM catalysts (L, F, C and M refer to metal La, Fe, Co and Mn, respectively) were prepared by co-precipitation method, respectively, and the effects of different calcination temperatures and doped elements on the catalytic performance of perovskite catalysts were systematically investigated in C2+ alcohols synthesis. Results of various characterizations show that the low calcination temperature can optimize the structural properties and adsorption behaviors of LF-600 (the numbers after “-” refer to the calcination temperature) catalyst, and the coupling of CO dissociation and non-dissociation sites on LF-600 catalyst helps to increase CO conversion and total alcohol selectivity to 16.9% and 31.2% (mass fraction), respectively. The doping of Co and Mn can change the product distribution and activity of LF-600 catalyst. Compared with LF-600 catalyst, LFC-600 catalyst promotes the chain growth due to the low H2 adsorption capacity, thereby increasing the proportion of C2+ alcohols in total alcohols from 60.4% to 71.6%. LFM-600 catalyst has more low-temperature H2 adsorption sites leading to methanol being the main alcohol product, while particle agglomeration and Mn and O aggregation caused by Mn doping can reduce the activity of LFM-600 catalyst.关键词：syngas;C2+ alcohols;perovskite catalysts;B-site doping;calcination temperature- 8
- |
- 0
- |
- 0
发布时间：2024-01-26 -
摘要：CO2 hydrogenation to methanol is one of the important ways to synthesize chemical value-added products, which helps to relieve energy and environmental pressure. CuZnAlZr catalysts for CO2 hydrogenation to methanol were synthesized by co-precipitation method, and the resulting catalysts were characterized by X-ray diffraction (XRD), N2O-H2 titration, N2 adsorption/desorption, H2 temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). And the effects of 1,3,5-benzenetricarboxylic acid (BTC) assisted synthesis on the dispersion of active Cu species in CuZnAlZr catalysts and their catalytic performance were investigated in detail. The results show that after the introduction of BTC into the CuZnAlZr catalysts precursor, the gas products generated by the decomposition in the calcining stage, contributes to the increase of the specific surface area of the catalyst and generates more pore structures, and it also weakens the interaction between Cu and the carrier oxide, which contributes to the dispersion of Cu species. When the amount of BTC introduced into the catalyst is n(BTC)/n(Cu2+) = 1/6, more highly dispersed smaller Cu grains and ZnO crystalline phases existe on the surface of the CuZnAlZr catalysts calcined in air and the enhanced synergy between Cu and ZnO species leds to excellent catalytic performance with CO2 conversion rate and methanol space-time yield up to 27.81% and 278.6 g/(kg·h), respectively. This indicates that the introduction of appropriate amount of BTC in the precursor to assist the synthesis can lead to highly active hydrogenation catalysts with high Cu dispersion and small Cu grains.关键词：1,3,5-benzenetricarboxylic acid;CuZnAlZr catalysts;CO2 hydrogenation;methanol- 10
- |
- 1
- |
- 0
发布时间：2024-01-26 -
摘要：One significant route for producing ethanol (EtOH) indirectly from syngas is the hydrogenation of coal-based syngas to EtOH via dimethyl oxalate (DMO) intermediates. There are two reaction pathways for DMO hydrogenation to EtOH: hydrogenation to EtOH via ethylene glycol (EG) intermediates and hydrogenation to EtOH via methyl acetate (MA) intermediates. The characteristics of two reaction pathways for DMO hydrogenation to EtOH were analyzed, and the catalysts commonly utilized in these pathways and the key factors affecting selectivity of EtOH were summarized. DMO hydrogenation to EtOH via EG intermediates typically requires high reaction temperature and synergistic catalysis of multiple active sites. The catalytic activity of commonly used Cu-based catalysts can be regulated from three aspects: support structure, preparation method and additive addition. The reaction temperature of DMO hydrogenation to EtOH via MA intermediates is relatively low, and commonly used catalysts are mainly transition metal carbides (Mo-base and Fe-base), but the hydrogenation capacity of catalysts is still insufficient. It helps to deepen the systematic understanding of the two pathways for DMO hydrogenation to EtOH and provides reference for the rational design and preparation of highly stable and low-cost catalysts for DMO hydrogenation to EtOH in the future.关键词：dimethyl oxalate;hydrogenation;ethanol;reaction pathways;syngas;catalysts- 15
- |
- 0
- |
- 0
发布时间：2024-01-26 -
摘要：Establishing a connection between active sites and supports using green and efficient methods is crucial for the construction of heterogeneous catalysts. The surface of industrial fly ash (CFA) was sulfurized through a sulfur dioxide (SO2) low-temperature plasma modification, resulting in a solid acid catalyst termed CFA-HSO3. This catalyst was then utilized for the conversion of xylose to furfural. Characterization of the samples was conducted using various techniques, including Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area and pore size analysis, organic elemental analysis (OEA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The yield of furfural in the catalytic reaction was enhanced by optimizing reaction conditions. The results indicate that the successful grafting of sulfur-containing functional groups onto the sample’s surface after SO2 low-temperature plasma modification. This approach can also reduce the catalyst’s preparation time. In a biphasic solvent system with a water-to-4-methyl-2-pentanone (MIBK) volume ratio of 1:3, adding 0.6 g of xylose, 0.2 g of NH4Cl, and 0.3 g of catalyst, and reacting at 190 °C for 20 minutes, the yield of furfural can reach 89.6%, which is 47.9% higher than that of pure water system. Furthermore, CFA-HSO3 exhibites excellent catalytic stability and reusability. This study introduces a green and efficient catalyst modification approach, offering a novel pathway for the preparation of furfural.关键词：SO2 low-temperature plasma technology;fly ash;solid acid catalyst;biphasic solvent system;xylose;furfural- 11
- |
- 1
- |
- 0
发布时间：2024-01-26 -
摘要：Methyl glycolate is an important chemical raw material, so it is of great significance to study the synthesis process of methyl glycolate. The synthesis process of methyl glycolate was introduced, including chloroacetic acid hydrolysis method, methyl formate and formaldehyde coupling method, formaldehyde carbonylation esterification method, dimethyl oxalate hydrogenation reduction method, synthesis of ethylene glycol and methanol, biomass conversion method, methylal and formic acid free radical coupling method, formaldehyde and hydrocyanic acid addition method and one-step synthesis of glyoxal and methanol method. The advantages and disadvantages of each process were analyzed. The application of methyl glycolate in the fields of degradable plastic, food, medicine, pesticide and chemical industry was pointed out. The research progress of methyl glycolate production technology was analyzed. Finally, the synthesis process of methyl glycolate was summarized and prospected. There are many problems in the traditional production process of methyl glycolate, and it is difficult to produce on a large scale. The dimethyl oxalate hydrogenation reduction method to synthesize methyl glycolate and then to synthesize ethyl ester and polyglycolic acid has broad development prospects in China. After solving the problems existing in the whole process, large-scale industrial production will be realized. Biomass conversion process uses renewable cellulose and other resources as raw materials to produce methyl glycolate, which has the advantages of green and low-carbon, and helps to achieve Double Carbon goals.关键词：methyl glycolate;synthesis process;dimethyl oxalate;polyglycolic acid- 18
- |
- 1
- |
- 0
发布时间：2024-01-26 -
摘要：Acetylene is widely used in various chemical industries. However, due to its unstable acetylenic bond, acetylene may explode under pressurized conditions. Therefore, measuring the acetylene solubility in various solvents poses great risks. To safely measure acetylene solubility, a micro solubility measurement device with an inner diameter of 0.8 mm quartz tube encapsulated with about 7 μmol acetylene was designed based on the intrinsic safety strategy of reduction and the solubility measurement principle of static saturation method, which could achieve the gas-liquid mass transfer balance within 1 to 2 h. The acetylene solubility in various solvents was measured with the device at a maximum temperature of 150 ℃ and a maximum pressure of about 0.5 MPa. The average relative absolute deviation between the Henry coefficients measured by the device and in the literature was 5.72%. With the advantages of low acetylene consumption, fast gas-liquid equilibrium speed, low equipment cost and easy operation, the device provides a safe and efficient method for measuring the solubility of hazardous gases represented by acetylene.关键词：acetylene;solubility;static saturation method;micro device;safe measurement- 11
- |
- 2
- |
- 0
发布时间：2024-01-26 -
摘要：Conventional steam methane reforming (SMR) reactor (cSMR reactor) often exhibit significant radial temperature gradients, increasing the risk of catalyst deactivation due to carbon deposits. A novel design, the Ohmic-heating fixed-bed reactor with inner and outer tubes for steam reformingr (eSMR reactor), has been proposed to replace the conventional combustion-based heating method employed in industrial reactor. Using a two-dimensional quasi-homogeneous fixed-bed reactor simulation, the performance differences between eSMR and cSMR reactor were compared, and the effects of eSMR reactor structure and operating conditions on its performance were analyzed. The results show that compared to cSMR, eSMR reactor exhibits a 26.6% higher outlet average methane conversion rate, a 121 K higher outlet average temperature, and a more uniform radial temperature distribution. When the inner-to-outer tube diameter ratio is 0.589, the radial temperature gradient is minimized in eSMR reactor. Increasing the inlet temperature, heating voltage, and steam-methane ratio all enhance the outlet average methane conversion rate and outlet average temperature in eSMR reactor, while the effect of increasing inlet pressure is the opposite. This research can offer valuable insights for the development of Ohmic heating-based steam methane reforming reactors.关键词：Ohmic-heating;steam methane reforming;fixed-bed reactor;mathematical model;optimal design- 15
- |
- 0
- |
- 0
发布时间：2024-01-26 -
摘要：Controlling carbon dioxide (CO2) emissions is crucial for environmental protection. An overview of current mainstream CO2 capture technologies was provided, including absorption and adsorption methods. The research progress of chemical process intensification technologies, including membrane separation, ionic liquids and hypergravity, in combination with absorption or adsorption methods for CO2 capture were introduced. CO2-enhanced oil recovery (CO2-EOR) is a significant storage and utilization method after CO2 capture, The typical cases of applying CO2 capture by chemical absorption method in CO2-EOR projects were introduced. It pointed out the need for further reduction in the energy consumption and cost of current CO2 capture technologies, as well as the enhancement of the quality and purity of CO2-EOR injection gas. An outlook on the future development of CO2 capture, utilization, and storage technologies was also provided.关键词：carbon dioxide capture;chemical absorption method;chemical process intensification;industrial application- 27
- |
- 6
- |
- 0
发布时间：2024-01-26 -
摘要：In recent years, under the background of global efforts to promote carbon neutrality, the development of carbon capture, utilization and storage (CCUS) technology has entered the “fast lane”. In the whole CCUS industry chain, carbon capture is both the first link and an important node. The commonly used carbon capture methods include chemical absorption method, membrane separation method and physical adsorption method, among which chemical absorption method is considered to be the most promising carbon dioxide capture technology at present, but high energy consumption and high cost limit its large-scale development. At present, the research of chemical absorption method mainly focuses on the optimization of absorbents to reduce energy consumption. Various chemical absorbents that have been reported in recent years were analyzed and summarized, mainly focusing on the absorption performance, absorption mechanism, advantages and disadvantages, and enhancement pathways, and their future development prospects were prospected, so as to provide reference for the development of high efficiency chemical absorbents.关键词：carbon dioxide;carbon capture;chemical absorption method;absorbent;post-combustion capture- 34
- |
- 1
- |
- 0
发布时间：2024-01-26 -
摘要：Natural gas is not only an efficient and low-carbon fossil energy, but also a high-quality and efficient chemical raw material. Therefore, under the dual-carbon goal, natural gas is an important force to achieve low-carbon energy transformation in China, and natural gas chemical industry is an inevitable choice for low-carbon, deep processing and utilization of natural gas. Firstly, from the aspects of resource guarantee, industrial base, regional development, technological innovation and policy guidance, the development status of natural gas chemical industry in China was summarized and analyzed, and it is generally stable. Then, from the aspects of industrial chain optimization, refined development, new material transformation and new energy expansion, the development path and development prospects of China’s natural gas chemical industry were analyzed and discussed, and the development prospects of natural gas chemical industry after reaching the peak were forecasted according to the prediction that China’s natural gas consumption will peak in 2035 to 2040.关键词：natural gas chemical industry;natural gas consumption;carbon emission;carbon peaking and carbon neutrality- 41
- |
- 5
- |
- 0
发布时间：2024-01-26 -
摘要：In the process of natural gas extraction and transportation, the presence of trace amounts of gaseous water may lead to hydrate formation with small gas molecules, resulting in pipeline blockages, so it is necessary to remove water from natural gas through dehydration. To establish appropriate parameters for the maximum permissible water content in natural gas, it is crucial to measure and calculate the gas-phase water content in gas-hydrate phase equilibrium accurately. Under the conditions of pressure from 3.44 MPa to 6.00 MPa and temperature from 270.00 K to 274.00 K, the gas-phase water content of methane-hydrate phase equilibrium was studied by experimental measurements and model predictions. The results show that compared with pressure dew point, atmospheric dew point and gas-phase water content volume ratio change regularly with temperature and pressure. Gas-phase water content decreases with the decrease of temperature and the increase of pressure. On the basis of experiments, a thermodynamic model of gas-phase water content in methane-hydrate phase equilibrium was established based on thermodynamic phase equilibrium theory. The average relative deviation between the predicted values and experimental values is 2.33%. This method achieves in situ measurement of gas-phase water content in methane-hydrate phase equilibrium system, and the established model is faster and more accurate than the method of obtaining the saturated water content in methane-liquid water phase equilibrium by looking up the diagram and extrapolating to the hydrate zone.关键词：hydrate;methane;phase equilibrium;gas phase water content;thermodynamic model- 11
- |
- 0
- |
- 0
发布时间：2024-01-26 -
摘要：Macroalgae does not require arable land and does not contain lignin that is difficult to pyrolysis, which is an ideal raw material for carbon reduction and the production of small molecule biofuels. The microwave-assisted pyrolysis of large seaweed (including kelp, grateloupia livida, ulva pertusa kjellm and sargassum miyabei) was studied and compared with that of larch. The temperature rise behavior, gas release behavior and hydrogen generation curve during microwave-assisted pyrolysis were studied and the product distribution, gas composition and gasification index were compared. Further, Ca-Al (CaO-Al2O3) sorbent was used to absorb carbon dioxide (CO2) generated by microwave-assisted pyrolysis of kelp in situ, and the directed conversion of kelp to hydrogen production was strengthened. The results show that macroalgae had faster heating behavior and better hydrogen production effect than larch, especially the hydrogen yield of kelp (16.40 g/kg) is three times that of larch. The addition of Ca-Al sorbent can further enhance the hydrogen production efficiency of kelp with microwave-assisted pyrolysis. When the mass ratio of kelp to Ca-Al sorbent is 1.0:3.0, the hydrogen yield can reach 44.24 g/kg, and the gasification efficiency reaches 68.57%, the content of hydrogen in the gas product is as high as 77.24%.关键词：Ca-Al sorbent;microwave-assisted pyrolysis;kelp;macroalgae;hydrogen- 16
- |
- 1
- |
- 0
发布时间：2024-01-26 -
摘要：In response to the characteristics of high synthesis gas temperature (> 200 ℃), high pressure (3.35 MPa), high saturated water content and complex components (including CH4, H2, CO2, CO, etc.) prepared by underground coal gasification (UCG) technology, a membrane separation + solvent absorption coupling treatment method was designed to achieve CO2 removal and H2 purification from underground coal gasification syngas. The underground coal gasification syngas was treated by a secondary membrane separation unit to achieve the separation of CO2/H2 and CH4, and the decarbonized purified gas is obtained, where the CO2 content (mole fraction) is less than 3%. The energy consumption required for this membrane separation process is 0.297 kW·h/m3. The CO2/H2 mixture was treated by amine absorption method, and the research was conducted by the methods of formula solution screening, process optimization and check analysis. Finally, the product with H2 purity (mole fraction) ≥ 99% is obtained. The energy consumption of the amine absorption method is 0.341 kW·h/m3. Using membrane separation + solvent absorption coupling treatment method to treat underground coal synthesis gas under complex working conditions, decarbonized purified gas, pure CO2 and industrial grade H2 can be obtained, greatly improving the economic value of the project and having great application potential.关键词：underground coal gasification;membrane separation;solvent absorption method;decarbonization;hydrogen extraction- 16
- |
- 1
- |
- 0
发布时间：2024-01-26
- Postal code：610225
- Tel：028-85964717 Email：dthxyhg@swchem.com
- Technical support is provided by Beijing Founder electronics co., LTD 蜀ICP备12008600号-10
蜀公网安备51012202001533 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
- Total Visits：48404 Visits Today：175
0