最新刊期
卷 49 ， 期 3 ， 2024
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摘要：The preparation of carbon-based fuels and high-value chemicals by carbon dioxide (CO2) catalytic hydrogenation is a promising carbon reduction technology, but its industrialization still faces many challenges. For the C1 products prepared by CO2 catalytic hydrogenation, including formic acid (HCOOH), carbon monoxide (CO), methanol (CH3OH) and methane (CH4), were reviewed from the aspects of reaction pathways and catalytic processes. Firstly, the reaction pathways and competitive relationships of different C1 products in CO2 catalytic hydrogenation were summarized. Then, the catalytic performance of different catalysts were discussed according to the modification methods of CO2 catalytic hydrogenation catalysts. Finally, the future development direction of CO2 catalytic hydrogenation catalysts was prospected.关键词：CO2;C1 products;catalytic hydrogenation;reaction pathways;catalysts- 146
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发布时间：2024-04-22 -
摘要：Silicon nitride is an excellent catalyst support with high hydrothermal and mechanical stability. The amino groups on its surface can effectively anchor metals, significantly enhancing metal dispersion. However, commercial silicon nitride has a relatively low surface area, limiting its effectiveness in metal dispersion. Therefore, high-surface-area self-prepared silicon nitride (Si3N4) was used as a support to prepare catalysts (0.5%Ru/Si3N4, 1.0%Ru/Si3N4 and 2.0%Ru/Si3N4, respectively) with different Ru loadings (0.5%, 1.0%, and 2.0% by mass fraction, respectively) via the impregnation method. Additionally, 2.0%Ru/Si3N4-C catalyst was prepared using commercial silicon nitride (Si3N4-C) as a control. Physicochemical properties of the catalysts were characterized, and their activities in the CO2 hydrogenation reaction at 300 ℃ and 0.1 MPa were tested. The results show that compared with Si3N4-C, Si3N4 has a higher surface area (502 m2/g), significantly improving metal dispersion and reducing metal particle size. Si3N4-based catalysts expose more active sites. The metal particle size of 0.5%Ru/Si3N4 is small, and the catalyst exhibits strong H2 adsorption capacity, and thus H is difficult to desorption, which inhibits the hydrogenation of CO intermediates to CH4. As the Ru loading increases, the metal particle size increases, and the CH4 selectivity of the catalysts is better. Among the Ru/Si3N4 catalysts, 2.0%Ru/Si3N4 shows higher CH4 selectivity (98.8%). At a space velocity of 10000 mL/(g·h), the CO selectivity of 0.5%Ru/Si3N4 is 88.2%. Compared with 2.0%Ru/Si3N4, 2.0%Ru/Si3N4-C has larger metal particle size, fewer active sites, and lower activity. The CO2 conversion rates of 2.0%Ru/Si3N4 and 2.0%Ru/Si3N4-C are 53.1% and 9.2%, respectively. Si3N4 effectively improves metal dispersion, enhancing the catalytic activity in CO2 hydrogenation. By adjusting the Ru loading to control the metal particle size of the catalyst, the selectivity of the product CO or CH4 can be controlled.关键词：CO2 hydrogenation;Ru/Si3N4 catalysts;CH4 selectivity;CO selectivity- 52
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发布时间：2024-04-22 -
摘要：Olefin hydroformylation reaction is an important process for the synthesis of aldehydes in industry. The cost of hydroformylation of olefin is greatly increased due to the difficulty of recovery of rhodium-based homogeneous catalyst. Multiphase catalysts loaded with solid phase are widely concerned because of their simple separation and recycling operation, but there are problems of poor reactivity, large metal loss and high cost of catalyst preparation, developing non-homogeneous rhodium catalysts with good catalytic and recovery performance have broad prospects. The research progress in multiphase loaded rhodium-based catalysts for olefin hydro formylation reactions was reviewed in four types of catalysts: inorganic solid carrier immobilized catalysts, HRh(CO)(PPh3)3 encapsulated multiphase catalysts, porous organic ligand (POL) material supported catalysts and single-atom intermetallic nano-catalysts. In multiphase loaded rhodium-based catalysts, the composition and preparation conditions of phosphine ligand, the types and properties of carriers, and the synergistic effect of rhodium with other metals can all affect their catalytic performance in olefin hydroformylation reaction. The advantages, disadvantages and development prospects of these four types of catalysts were briefly analyzed. In future studies, it is suggested to design phosphine ligands with strong electron-feeding ability and high spatial site resistance, explore inorganic/organic carriers with high specific surface area and multi-level pore structure, deeply explore the interactions between metal nanoparticles, and further improve the catalytic performance and recovery performance of rhodium-based catalysts in olefin hydroformylation reaction.关键词：olefins;hydroformylation;non-homogeneous catalysts;rhodium-based catalysts- 50
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发布时间：2024-04-22 -
摘要：Vinyl acetate (VAc) is an important chemical raw material with well application value. With the rapid development of the photovoltaic industry and the improvement of environmental protection requirements, the demand for high-quality vinyl acetate (i.e., ethylene gas phase process vinyl acetate) in China is increasing year by year. It is of great significance to develop the catalyst with high catalytic activity, high target product selectivity, high stability and low cost. Firstly, the development of catalysts for producing ethylene acetate by ethylene gas phase process was reviewed. The functions of catalyst supports, active components and potassium acetate additive were summarized. The two reaction mechanisms of producing vinyl acetate by ethylene gas phase process and the deactivation causes of Pd-Au catalyst were analyzed. The preparation process of eggshell Pd-Au catalyst by impregnation method was described. Then the research results of catalyst improvement for the purpose of further improving catalytic performance and reducing catalyst cost were summarized, including modification and deformalization of supports, and improvement of procedures, such as impregnation of active components, aging, reduction, washing and drying. Lastly, the research direction of catalyst for producing vinyl acetate by ethylene gas phase process in the future was proposed.关键词：vinyl acetate;ethylene gas-phase process;Pd-Au catalyst;catalyst improvement- 48
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发布时间：2024-04-22 -
摘要：The unique pore structure of H-ZSM-12 zeolite is conducive to the formation of multi-branched isomers in long chain alkane hydroisomerization, but its strong acidity exacerbates the occurrence of cracking reactions. Substitution of Fe for Al in the framework of zeolites could effectively reduce the acid strength. In order to improve the selectivity of i-alkanes, Z12-Al, Z12-Al-Fe and Z12-Fe zeolites with Fe-substitution degrees (calculated as n(Fe):n(Al + Fe)) of 0%, 50% and 100%, synthesized by hydrothermal method. The characterization results of ultraviolet-visible absorption spectroscopy (UV-Vis) indicate that the majority of Fe introduced in Z12-Al-Fe and Z12-Fe exist in the molecular sieve framework in the form of [FeO4]. The characterization results of infrared absorption spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) indicate that Fe in the H-Z12-Al-Fe and H-Z12-Fe frameworks combines with Si—OH to form Si—OH—Fe bonds. The temperature programmed desorption of ammonia (NH3-TPD) and pyridine infrared (Py-IR) characterization results indicate that with the increase of Fe content in the zeolite, the acid strength of its strong acid site gradually decreases, and the total amount of Brønsted acid significantly decreases. After loading sufficient metal Pt on the zeolite support, the hydroisomerization performance of the bifunctional catalyst was evaluated using n-dodecane (n-C12) as a model compound (reaction pressure is 2.0 MPa, n(H2):n(n-C12) is 6.0). The reaction results show that the decrease in Brønsted acid strength and acid sites quantity of Pt/H-ZSM-12-Fe results in lower catalytic activity than Pt/H-ZSM-12-Al. However, the inhibition of weak Brønsted acids on cracking reaction results in the highest total isomers selectivity (85.7%) and multi-branched isomers selectivity (53.8%) at a n-C12 conversion rate of about 90%, which are 18.6% and 9.7% higher than Pt/H-Z12-Al, respectively. In addition, Pt/H-Z12-Fe exhibited excellent stability in a continuous reaction of 120 h.关键词：ZSM-12 zeolite;Brønsted acid tuning;Fe-substituted;n-dodecane;hydroisomerization- 69
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发布时间：2024-04-22 -
摘要：Vinyl ether is an important polymeric monomer, but the systematic thermodynamic analysis of its synthesis has not been reported. By utilizing Benson and Joback method and other methods respectively, based on classical thermodynamic formulas, the thermodynamic parameters of corresponding vinyl ethers compounds (vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, vinyl isobutyl ether and vinyl tert-butyl ether) synthesized from acetylene with different alcohols (methanol, ethanol, butanol, isobutyl alcohol and tert-butyl alcohol) were calculated, including enthalpy change (- 65
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发布时间：2024-04-22 -
摘要：The utilization of mixed C5, by-products of methanol-to-olefins (MTO) process, is relatively limited, which affects the overall economic efficiency of the MTO industry. MTO mixed C5 is mainly composed of mono-olefins, whereas in the petrochemical field, the mixed C5 from ethylene cracking is mainly composed of di-olefins. Therefore, the utilization technologies of the latter cannot be directly applied to the former. The existing mature technologies for the utilization of MTO mixed C5 were reviewed, mainly cracking technologies for increasing propylene and ethylene, such as the olefins catalytic cracking (OCC) technology from SINOPEC Shanghai Research Institute of Petrochemical Technology Co., Ltd., the olefins cracking process (OCP) technology developed through collaboration between Total Energies from France and UOP from the United States, the DMTO-II technology from Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and the mixed C5 recycling and pre-carbon deposition technology from China Energy Investment Corporation. The potential pathways for value-added utilization of MTO mixed C5 were summarized, including the etherification of mixed C5 to produce gasoline blending components, the separation of high-purity isopentene from mixed C5, the aromatization of methanol and mixed C5 to produce aromatic hydrocarbons, and the co-cracking of methanol and mixed C5 to produce low-carbon olefins. The main problems faced in the utilization of MTO mixed C5 and the future development prospects were expounded. It is suggested that the development of efficient coupling technology for the utilization of mixed C5 with MTO devices and the exploration of downstream markets for coal-based mixed C5 are the main directions to enhance the value of mixed C5.关键词：methanol-to-olefins;mixed C5;isopentene;comprehensive utilization- 63
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发布时间：2024-04-22 -
摘要：Three technologies for recovering ethylene from catalytic dry gas, including cryogenic separation, absorption separation, and pressure swing adsorption separation, were introduced. In the context of a structural adjustment of a petrochemical company’s refining process, where the catalytic dry gas production capacity increased from 15 × 104 t/a to 21 × 104 t/a, pressure swing adsorption technology was chosen due to its advantages, such as simple operation, no need for auxiliary materials, rapid and stable unit operation under changing conditions, and low comprehensive energy consumption. Following the principles of capacity expansion and renovation, the previous two-stage process was converted into a single-stage process. The number of towers in the vacuum step was increased from 2 to 3, and the number of towers in the adsorption step was increased from 4 to 5. The results show that after the capacity expansion and renovation, comprehensive energy consumption is reduced by approximately 14% with product quality remaining comparable, and the operation indicators improve, compared to before the modification. In the background of reducing carbon emissions, pressure swing adsorption separation technology has an application advantage due to its lower comprehensive energy consumption compared to other technologies.关键词：catalytic dry gas;pressure swing adsorption separation technology;ethylene recovery- 41
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发布时间：2024-04-22 -
摘要：In order to achieve four-way purification of soot (ST), nitrogen oxides (NOx), hydrocarbons (HC) and carbon monoxide (CO) in diesel exhaust, four kinds of La0.8Ce0.2Fe0.3Co0.7O3 woody perovskite-type catalysts (LCFCO-600, LCFCO-700, LCFCO-800 and LCFCO-900, respectively) were prepared by using wood fiber as biomass templates and calcination at 600 ℃, 700 ℃, 800 ℃ and 900 ℃, respectively. The micromorphologies of the catalysts were observed by scanning electron microscope (SEM), and the elemental composition and corresponding proportion of LCFCO-800 were analyzed by energy spectrum (EDX). The crystal structure and phase composition of the catalysts were characterized by X-ray diffraction (XRD). The typical chemical bonds of the catalysts were analyzed by Fourier transform infrared spectroscopy (FT-IR). The structure parameters of the catalysts were analyzed by N2 adsorption/desorption. The four-way purification performance of the catalysts were evaluated by simulation experiments. The results show that the prepared catalysts have obvious biomass structure and high perovskite phase purity, among which LCFCO-800 has the largest specific surface area, total pore volume and average pore size, which are 3.270 m2/g, 0.017 cm3/g and 20.486 nm, respectively, and LCFCO-800 has good four-way purification performance. Under the conditions of simulated exhaust temperature of 400 ℃, flow rate of 1 L/min and purification time of more than 120 s, the maximum purification efficiency of LCFCO-800 for ST, NOx, HC and CO is 92%, 92%, 98% and 76%, respectively. In addition, according to the Mars-van Krevelen REDOX reaction mechanism and experimental results, the four-way purification mechanism of the catalyst was analyzed. It is concluded that the increase of ST mass concentration can inhibit the oxidation of HC and CO, and the oxidation process of ST, HC and CO can help to generate more oxygen vacancies on the surface of catalysts, thus promoting the reduction of NOx.关键词：diesel engine exhaust;wood fiber;perovskite-type catalysts;four-way purification- 27
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发布时间：2024-04-22 -
摘要：Carbon capture, utilization and storage (CCUS) technology is an important measure to reduce carbon dioxide (CO2) emissions and mitigate climate change issues. As an important component of CCUS technology, CO2 geological storage is the “bottom line” technology for achieving carbon neutrality goals in China’s energy industry. Common geological formations for CO2 storage include deep brine aquifers, depleted oil and gas reservoirs, deep unminable coal seams, and basalt formations. The processes and mechanisms of CO2 storage in different geological formations are different. The CO2 storage mechanisms in different geological formations, the main engineering examples of CO2 storage at home and abroad, and the calculation methods of CO2 storage potential in different geological formations were summarized. The prospects for CO2 geological storage were discussed.关键词：CO2 geological storage;CO2 storage mechanism;geological storage project;storage potential calculation- 30
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发布时间：2024-04-22 -
Accounting for carbon dioxide emissions and exploring carbon reduction in petrochemical enterprises AI导读
摘要：In order to understand the carbon emissions of a petrochemical enterprise and develop emission reduction measures, an annual carbon dioxide (CO2) emissions accounting for the enterprise was conducted, following relevant guidelines. The scope of the accounting includes power generation facilities and petrochemical equipments. For processes contributing significantly to CO2 emissions, effective and rational emission reduction measures were implemented or planned, including side-line tests for CO2 capture and purification, establishing a demonstration unit for CO2 capture in coal-fired flue gas, researching and applying nitrous oxide (N2O) decomposition catalysts, and enhancing the electrification rate of equipments. The implementation of carbon reduction measures directly or indirectly reduces the enterprise’s CO2 emissions, which promotes the progress in low-carbon environmental protection, energy conservation and consumption reduction, and quality and efficiency enhancement, which can provide reference for similar enterprises.关键词：carbon dioxide;carbon dioxide emissions accounting;petrochemical enterprises;carbon reduction measures- 27
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发布时间：2024-04-22 -
摘要：The goal of carbon peaking and carbon neutrality has promoted the development of renewable energy in China, and the high proportion of unstable power is facing challenges in achieving large-scale energy storage and cross-regional consumption. Hydrogen energy storage, in its broader sense, involves using renewable energy to electrolyze water to produce hydrogen, which is along with hydrogen-based chemicals, serves as a medium for energy storage and consumption. Green electricity synthesis (Power-to-X, PTX), combined with CO2 chemical conversion technology, harnesses the rapid growth of the hydrogen industry to produce zero-carbon products such as methane, methanoll and ammonia. These products can enter existing energy infrastructure systems, enabling high density, low-cost energy storage, transportation, and distribution, quickly addressing consumption without altering end-use habits. Explanations and analyses of green methane, green methanol and green ammonia production using green electric power were provided, and it is proposed that PTX can promote the integration of renewable energy with existing industries, thus achieving efficient utilization and consumption of renewable energy with broad prospects.关键词：hydrogen energy storage;Power-to-X;Power-to-Methane;green methanol;green ammonia- 29
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发布时间：2024-04-22 -
摘要：As a clean and efficient way to produce hydrogen energy, alkaline electrolytic water technology is relatively mature and widely used. The diaphragm is an important part of the electrolytic cell and plays a key role in the electrolysis performance of the cell. Based on the purpose of reducing the electrolysis voltage of hydrogen production by electrolytic water, by analyzing and testing the structural characteristics and conductivity of different types of diaphragm, combined with the comprehensive evaluation of their electrolytic performance in electrolytic cell, the relationship between the structure and performance of the diaphragm was explored, and the diaphragm material suitable for alkaline electrolyzed water was optimized. Polymer diaphragms were screened according to the indicators of diaphragm performance required for alkaline water electrolysis, such as diaphragm conductivity, porosity, alkali resistance, bubble permeability, wettability, mechanical strength and thermal stability. Several domestic and imported commercial polymer porous diaphragms of different specifications and models were selected. Through a comprehensive comparison of several domestic and imported commercial polymer diaphragms with different specifications and models, it is found that the imported AGFA-IV diaphragm have the best performance, with a porosity of 60% ± 10% and a diaphragms conductivity of 51.7 cm-1·Ω-1. An electrolytic cell was assembled and the electrolytic performance of the AGFA-IV diaphragm was tested on this basis. The results show that the electrolytic cell based on the imported AGFA-IV diaphragm has the lowest water electrolysis voltage during the electrolysis test, which is 1.841 V at the 0.4 A/cm2. Therefore, it is determined that the imported AGFA-IV diaphragm is the optimal material for the system. The research helps to better understand the basic knowledge of the diaphragm in the process of alkaline electrolytic cell electrolysis, and plays a certain role in the design and construction of high-performance diaphragm for alkaline electrolytic water.关键词：alkaline electrolytic water;electrolytic cell;diaphragm;conductivity;electrolytic voltage- 34
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发布时间：2024-04-22 -
Research status and analysis of hydrogen-blended natural gas transportation in natural gas pipelines AI导读
摘要：Hydrogen-blended natural gas transportation is one of the ways to achieve large-scale, long-distance and low-cost hydrogen transportation, but the blending of hydrogen into natural gas pipelines significantly affects the operation condition and safety maintenance of natural gas pipelines, posing potential safety risks. Therefore, based on the current domestic and foreign research and engineering applications status of hydrogen-blended natural gas transportation in recent years, the main factors affecting safe hydrogen-blended natural gas transportation in natural gas pipelines, including the change of natural gas physical properties caused by hydrogen blended, hydrogen-induced failures and uneven mixing, as well as the safety problems including leakage, diffusion and detonation were discussed. The analysis indicates that new requirements are put forward for the pipe materials with the hydrogen blended. Thus, relevant systematic experiments are needed to reveal the mechanism of hydrogen-induced failures. Whether gas stratification occurs after the shutdown of hydrogen-blended natural gas pipelines is closely related to whether the pipeline is hydrogen-induced failure. The safety range of diffused spontaneous combustion, the minimum hydrogen blending ratio and the mechanism of detonation are still unclear, and the gap between experiments and practice is significant. The establishment of standards and associated regulatory policies for hydrogen-blended natural gas pipelines is still in the development stage, so improvement is required based on the systematic research data and practical implementation. The above results clarify the risks related hydrogen-blended natural gas transportation and can provide reference for the promotion and practical operation of large-scale hydrogen-blended natural gas transportation projects.关键词：hydrogen-blended natural gas;pipeline transportation;hydrogen blending ratio;leakage and diffusion;detonation- 85
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发布时间：2024-04-22 -
摘要：China has initiated coal-based synthetic natural gas (SNG) demonstration projects since the “Eleventh Five-Year Plan”. Environmental issues and economic viability have long been critical challenges restricting the development of the coal-based SNG industry. With the carbon peaking and carbon neutrality goals, there is enormous growth potential in China’s natural gas consumption from 2035 to 2040. Fluctuations in the international natural gas market have further heightened demands for supply security. As a significant form of modern coal chemical industry, coal-based SNG is conducive to promoting the clean and low-carbon utilization of coal. The opportunities and challenges in China’s coal-based SNG industry were analyzed. The diversification of natural gas supply and the requirement of secure reserves present a historic opportunity for the coal-based SNG industry. However, challenges such as weak competitiveness in end markets and environmental issues, including high carbon emissions, pose long-term obstacles to the industry. The production costs of coal-based SNG and the comprehensive costs to reach the end market were analyzed. Economic comparisons were made with other gas sources within three natural gas regional markets: Bohai Rim, Yangtze River Delta, and Central China. Considering the increasing trend in coal-based SNG production capacity and supply capabilities, it is projected that the demand for the coal-based SNG market in China will rise before 2030. Coal-based SNG will play a crucial role in providing abundant terminal gas sources and emergency supply.关键词：coal-based synthetic natural gas;natural gas reserve;economic viability;carbon emissions;demand forecast- 37
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发布时间：2024-04-22
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