最新刊期
卷 49 ， 期 2 ， 2024
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摘要：Supported catalysts are crucial in low-carbon catalytic conversion, and metal-support interactions is widely present in supported catalysts. These interactions play a vital role in determining the physical and electronic structure of these catalysts, and not only regulate the catalytic activity and stability of active metals but also enable the synergistic catalysis effect between metals and supports, thus promoting the selective catalytic conversion of low-carbon hydrocarbons, alcohols and other compounds. Hence, understanding the metal-support interactions is essential for the optimization of catalysts and exploring catalytic mechanisms deeply. The research progress in characterization of metal-support interactions using ex situ and in situ techniques were discussed. Ex situ characterization techniques, such as high-resolution electron microscopy, vibrational spectroscopy, X-ray spectroscopy and electron paramagnetic resonance spectroscopy can investigate mass transport and charge transfer between metals and supports. In situ characterization techniques, such as in situ infrared spectroscopy, in situ X-ray spectroscopy and in situ electron paramagnetic resonance can characterize the strength changes of metal-support interactions, changes of interface structures and compositions of catalysts during reactions, as well as the dynamic charge transfer processes.关键词：metal-support interactions;characterization techniques;static properties;dynamic properties- 218
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发布时间：2024-02-28 -
摘要：CO2 hydrogenation to high-carbon hydrocarbons (C5+) is one of the important ways to synthesize high-value chemicals and fuels, which can achieve carbon emission reduction as well as help to alleviate energy pressure. K- and Na-modified FeCoCuAl catalysts were prepared by precipitation and iso-volumetric impregnation methods, and the effects of the pore-forming agent 1,3,5-benzenetricarboxylic acid (BTA) on their catalytic performance in CO2-catalyzed hydrogenation to high-carbon hydrocarbons reaction(temperature of 300 ℃, pressure of 2.0 MPa, n(H2):n(CO2) = 3:1 and space velocity of 3600 h-1 of feed gas, reaction for 6 h) were investigated. ZSM-5 molecular sieve was introduced into FeCoCuAl-20.0BTA catalyst (n(BTA):n(Fe) = 20.0%) to construct a series of composite catalysts and their catalytic performance in the reaction of catalytic hydrogenation of CO2 to high-carbon hydrocarbons was investigated. The physicochemical properties of the catalysts were characterized by combining N2 adsorption/desorption, X ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), CO2 temperature programmed desorption (CO2-TPD), and H2 temperature programmed desorption (CO2-TPD), and the oil-phase compositions of the products were analyzed by GC-MS. The results show that compared with FeCoCuAl catalysts, the specific surface area and pore volume of FeCoCuAl-BTA catalysts increase, and generate more surface-active species (Fe or Fe-Co alloy), which lead to better catalytic performance of FeCoCuAl-BTA catalysts in CO2 catalytic hydrogenation reaction. The CO2 conversion rate and C5+ selectivity of FeCoCuAl-20.0BTA catalyst are up to 70% and 42%, respectively, and the products generated from CO2 hydrogenation catalyzed by FeCoCuAl-20.0BTA catalyst are mainly C2~C4 products, while on the composite catalyst constructed with FeCoCuAl-20.0BTA catalyst and ZSM-5 molecular sieve in the form of mechanical mixing of particles with the mass ratio of 1.0, the C2~C4 products generated on FeCoCuAl-20.0BTA can undergo in situ chain growth, isomerization and aromatization reactions on ZSM-5 molecular sieves, which lead to the improvement of CO2 conversion rate and C5+ selectivity, reaching 79% and 66%, respectively.关键词：pore-forming agent;FeCoCuAl catalysts;ZSM-5;CO2 hydrogenation;high-carbon hydrocarbons- 111
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发布时间：2024-02-28 -
摘要：Methanol dehydrogenation to methyl formate is a green and efficient way to diversify methanol downstream products. The modification of Cu/SiO2 catalyst with additive has become an effective strategy to increase the yield of the target product methyl formate. Firstly, spherical SiO2 supported Cu catalyst (Cu/SiO2) was prepared by the sol-gel method, and then a series of CuM/SiO2 (M = Ce or Al) catalysts were obtained through the introduction of additive to Cu/SiO2 via the rotary evaporation method. The catalysts were characterized by N2 absorption/desorption, scanning electron microscopy (SEM), H2-N2O titration, X-ray diffraction (XRD) and so on, and their catalytic performances were evaluated for the reaction of methanol dehydrogenation to methyl formate. The results show that the additive can change the content of active Cu0 species and the surface acidity of the catalysts. Compared with the Cu/SiO2 catalyst, the dispersion of Cu particles on the surface of CuCe/SiO2 catalyst is increased, which promotes the formation of the active species Cu0, while the surface alkaline site is reduced, which inhibits the occurrence of side reactions, and thus exhibits the highest activity. Under the reaction conditions of 300 °C and 0.2 MPa, the methanol conversion rate and the selectivity of methyl formate of CuCe/SiO2 catalyst are 29.2% and 86.3%, respectively, and the yield of methyl formate is 25.2%, which are obviously better than that of Cu-based catalysts reported in the literature.关键词：methanol dehydrogenation;copper-based catalyst;spherical SiO2;methyl formate;additive- 84
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发布时间：2024-02-28 -
摘要：In order to develop catalysts based on high thermal conductivity support and improve the performance of Fischer-Tropsch synthesis, ball milling boron nitride (BN) with high specific surface area was used as support to prepare a series of Fe/BN catalysts (Fe/BN-120, Fe/BN-160 and Fe/BN-200) by solvothermal method (solvothermal temperatures are 120 ℃, 160 ℃ and 200 ℃, respectively), and their catalytic performance in Fischer-Tropsch synthesis was studied (temperature of 280 ℃, pressure of 2.0 MPa, V(H2):V(CO):V(Ar) = 16:8:1 and space velocity of 3000 mL/(g·h) of syngas , measured by the reaction result at 48 h). The catalysts were characterized by N2 absorption/desorption, inductively coupled plasma-atomic emission spectrometer (ICP-AES), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and H2/CO temperature programmed reduction (H2/CO-TPR). The results show that compared with Fe/BN-120, the average particle size of γ-Fe2O3 in Fe/BN-160 and Fe/BN-200 increases from 7.2 nm to 13.6 nm and 14.7 nm, respectively, and the binding energy of Fe 2p gradually shifts towards the lower binding energy. Compared with Fe/BN-120 and Fe/BN-160, the reduction and carbonization of Fe/BN-200 are significantly promoted under the action of electronic effect and size effect. In the atmosphere of CO2 and H2O in Fischer-Tropsch, the reduced α-Fe and Fe3O4 react with the BOx on the surface of ball milling boron nitride under high temperature conditions to produce iron borate. With the increase of solvothermal temperature, the carbonization degree of catalyst increases gradually. Compared with Fe/BN-120 (CO conversion rate is 39.1%, CH4 selectivity is 24.3%, C5+ selectivity is 37.8%), CO conversion rate of Fe/BN-200 increases to 68.9%, CH4 selectivity decreases to 12.9% and C5+ selectivity increased to 51.1%. The catalytic activity and product distribution can be regulated by changing the solvothermal temperature on Fe/BN catalyst, which provides a way to improve the performance of Fe-based catalyst supported by boron nitride.关键词：Fischer-Tropsch synthesis;iron-based catalyst;boron nitride;solvothermal method;catalytic activity- 66
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发布时间：2024-02-28 -
摘要：Catalytic conversion of carbon-neutral and renewable biomass into liquid fuel and fine chemicals is one of main solutions to achieve carbon peaking and carbon neutrality goals, and γ-valerolactone (GVL) can be used as a green solvent and can be synthesized into high-grade aviation fuel. Levulinic acid (LA), as an important biomass-derived platform chemical, can be catalytically hydrogenated into highly value-added GVL. Biomass composition was briefly introduced first, and then the research progress of LA hydrogenation to GVL was fully reviewed based on the perspective of homogeneous and heterogeneous catalysts (Ru, Pd, Ni, Cu and bimetal). The catalyst structural properties, reaction performance, stability, structure-performance correlation and reaction mechanism were discussed in detail. Finally, the major challenges were analysized, future prospects and development trend for LA hydrogenation to GVL were further prospected, which can provide a basis for designing high-activity and acid-resisting Ru-based catalysts with large-scale commercial applications.关键词：biomass;levulinic acid;hydrogenation;γ-valerolactone;catalyst- 58
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发布时间：2024-02-28 -
摘要：Aluminum oxide (Al2O3) support is one of the most widely used catalytic materials, and replacing linear Al2O3 support with spherical Al2O3 support has become a major trend, so it is urgent to develop novel green and feasible methods for producing spherical Al2O3 support. Firstly, spherical Al2O3 with excellent sphericity, high strength and large specific surface area was prepared by nucleation-coating method: using pseudo boehmite as the raw material, nitric acid as the peptiser and hydroxypropyl methyl cellulose as the binder to optimize the rolling ball method. The effects of water-powder ratio (mass ratio), acid-powder ratio (mass ratio), binder content (mass fraction) and blasting time on the strength and pore structure of spherical Al2O3 were investigated by characterization methods such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that spherical Al2O3 with uniform particle size, high yield and high average compressive strength of 43.0 N can be prepared by controlling the acid-powder ratio of 0.050, water-powder ratio of 0.88, binder content of 3% (mass fraction) and blasting time of 5 min. Furthermore, spherical and powder PtSn/Al2O3 catalysts were prepared and applied to propane dehydrogenation at 618 ℃, H2 and C3H8 flow rate of 3.6 mL/min and 6.0 mL/min, respectively. The spherical PtSn/Al2O3 catalyst shows similar activity and selectivity as the powder PtSn/Al2O3 catalyst. Nucleation-coating method is green and efficient to prepare spherical Al2O3 support, which provides inspirations for localization of spherical Al2O3 support.关键词：spherical Al2O3;nucleation-coating method;Al2O3 molding;strength;propane dehydrogenation- 52
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发布时间：2024-02-28 -
摘要：As an aliphatic polyester, poly (ethylene succinate) (PES) has good mechanical properties and full biodegradability, which has broad application prospects in the field of degradable plastics. Titanyl acetate was prepared by solvothermal method and used as a catalyst to catalyze the esterification and polycondensation of succinic acid (SA) and ethylene glycol (EG) to synthesize high molecular weight PES. The effects of catalyst dosage (the mass fraction of catalyst in the reaction material, the same below), reaction temperature and reaction time on the molecular weight of PES were investigated. The structures of PES were characterized by 1H-NMR and 13C-NMR, and its thermal properties, thermal stability and mechanical properties were tested. The results show that the intrinsic viscosity coefficient [η] of the synthesized PES is 0.78, the number average molecular weight (Mn) is 47500, and the corresponding polymer dispersion index (PDI) is 2.66 when the catalyst dosage is 0.6% and the polymerization is carried out at 230 °C for 8 h. The melting point temperature of PES is 102.4 °C, the maximum thermal decomposition temperature is 420.2 °C, the elongation at break is 505% ± 5%, the tensile stress is (48.3 ± 0.6) MPa, and the tensile elastic modulus is as high as 358.8 MPa. The synthesis of PES using coal-to-ethylene glycol as a monomer can not only achieve low-cost preparation of fully biodegradable polymers, but also has important practical significance for the high-quality development of the coal chemical industry.关键词：titanyl acetate;coal chemical industry;biodegradable polymers;ethylene glycol;poly (ethylene succinate)- 80
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发布时间：2024-02-28 -
摘要：In the aromatization reaction of propane, the conventional molecular sieve catalyst is prone to carbon deposition and deactivation, resulting in unsatisfactory catalytic performance and service life. Nanometer ZSM-5 molecular sieve (ZSM-5-Nano) was synthesized with pure silica molecular sieve Silicalite-1 (S-1) as seed by combination with seed method and pre-crystallization method. The structure of ZSM-5-Nano was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and N2 physical adsorption/desorption. The results show that ZSM-5-Nano is composed of small particles with a particle size of about 50 nm, its specific surface area is up to 395 m2/g, and it is rich in intergranular mesopores. The catalyst Zn-ZSM-5-Nano was prepared by loading Zn with ZSM-5-Nano, and then the catalytic performance of the catalyst for the aromatization reaction (n(N2):n(C3H8) = 7:3, space velocity of 3000 h-1 and reaction temperature of 550 °C) of propane was evaluated in a fixed bed reactor. The results show that Zn/ZSM-5-Nano has relatively mild acid properties, and shows good catalytic performance in the aromatization reaction of propane. The conversion rate of propane and the selectivity of light aromatics (benzene, toluene and xylene) within 5 h are as high as 88.4% and 86.7%, respectively, and the activity is stable within 5 h. The catalytic performance is better than that of the micrometer ZSM-5 molecular sieve (hydrothermal method) supported Zn catalyst and the nanometer ZSM-5 molecular sieve (pre-crystallization method) supported Zn catalyst. The results of structure activity analysis show that the better catalytic performance of Zn/ZSM-5-Nano is the result of the combination of morphology and acidity, and the shorter diffusion distance and milder acidity effectively delay the formation of carbon deposition.关键词：propane aromatization;seed induced;pre-crystallization;nano ZSM-5 molecular sieve- 50
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发布时间：2024-02-28 -
摘要：In the complexation denitrification reaction, the reduction and regeneration of Fe(II)EDTA complexation denitrification solution is one of the application difficulties, and formic acid/sodium formate system has a good reducing property on Fe(II)EDTA complexation denitrification solution under the action of palladium carbon (Pd/AC) catalyst. On this basis, the effects of ultrasonic power, formic acid amount, sodium formate amount and Pd/AC catalyst amount on the reduction and regeneration of Fe(II)EDTA complexation denitrification solution (denitrification efficiency is 80%) were investigated by using control variable method. The results show that under the action of Pd/AC catalyst without ultrasonic, the formic acid/sodium formate reduction system can effectively reduce NO in Fe(II)EDTA complexation denitrification solution, and achieve the reduction and regeneration of the complexation denitrification solution. When the amount of sodium formate is 10.00 g/L, the amount of formate is 2.10 g/L, and the amount of Pd/AC catalyst is 3.00 g/L, the denitrification performance of the regenerated complexation denitrification solution exhibits the best denitrification performance at 50 ℃ (the denitrification efficiency reaches more than 97% within 60 min and the denitrification efficiency reaches more than 80% within 90 min). After several times of continuous complexation denitrification and reduction regeneration experiments, the whole system still has good denitrification performance (at the 6th switching, the denitrification efficiency is about 85% within continuous absorption for 70 min to 80 min). The results can provide reference for the pilot test and engineering application of continuous complexation denitrification.关键词：Fe(II)EDTA complexation denitrification solution;reduction regeneration;formic acid/sodium formate system;palladium carbon catalyst;continuous experiment- 76
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发布时间：2024-02-28 -
摘要：In order to solve the problems of high energy consumption, low helium extraction efficiency and high economic cost of traditional helium extraction process, the process of low-temperature and membrane separation for helium extraction from natural gas and the process of low-temperature helium extraction and LNG co-production from natural gas were analyzed. Combined with the advantages of each process, the process of low-temperature and menbrane separtion for helium extraction and LNG co-production from natural gas was designed. Aspen HYSYS software was used to simulate the comprehensive energy consumption, helium recovery rate and helium content (volume fraction, the same as below) of the three processes. The results show that the helium recovery rate of the process of low-temperature and membrane separation for helium extraction and LNG co-production from natural gas is the highest when the condition of the minimum operating temperature is -188.3 ℃, which can reach 99.99%. The extracted helium content is the highest (up to 99.95%), and LNG production is 678.4 kmol/h, and LNG liquefaction rate is 94.6%. Compared with the operational parameters of the process of low-temperature and membrane separation for helium extraction from natural gas and the process of low-temperature helium extraction and LNG co-production from natural gas, the total compressor energy consumption of the process of low-temperature and membrane separation for helium extraction and LNG co-production from natural gas is reduced by 12.68%, and the comprehensive energy consumption of the device is reduced by 18.75%. The final process of low-temperature and membrane separation for helium extraction and LNG co-production from natural gas can effectively improve helium recovery rate and purity, reduce energy consumption and investment costs, maximize energy utilization, and produce two products (refined helium and LNG) at the same time.关键词：natural gas;low-temperature and membrane separation;helium extraction;LNG co-production;process simulation- 47
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发布时间：2024-02-28 -
摘要：Carbon capture, utilization and storage (CCUS) technology is one of the effective measures to reduce carbon dioxide (CO2) emissions, among which chemical absorption method is widely used and mature technology. In the chemical absorption method, after absorbing CO2 with alkaline solution, there is a certain amount of bicarbonate and carbonate in the CO2 absorption solution, and the total amount of bicarbonate and carbonate in the CO2 absorption solution can be determined accurately. According to the water quality components and complexity of desulfurization wastewater (using as CO2 absorption solution), EDTA indirect titration method was proposed to rapidly determine the total amount (measured in carbonate, the same as below) of bicarbonate and carbonate in CO2 absorption solution. The results of the determination of bicarbonate and carbonate series standard solutions show that the linear fitting coefficients of the standard curves of the series of standard solutions are greater than 0.9993, and the linear fitting range is from 100 mg/L to 2500 mg/L. Therefore, the detection range of the total amount of bicarbonate and carbonic acid by EDTA indirect titration is from 100 mg/L to 2500 mg/L. The results of actual engineering water samples show that the relative standard deviation of the measurement results is from 0.92% to 1.28% with n = 5, and the accuracy is good. The EDTA indirect titration method is feasible for the determination of bicarbonate and total carbonate.关键词：CO2 chemical absorption;quantitative detection;indirect titration;desulfurization waste water- 44
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发布时间：2024-02-28 -
摘要：Developing an economical, efficient and energy-saving carbon capture process is one of the key research directions in carbon capture, utilization, and storage technology. A coupling system process for carbon capture based on liquefied natural gas (LNG) cold energy was proposed to address low-concentration (volume fraction less than 12%) CO2 flue gas. The process combines membrane separation and cryogenic separation, compensating for the shortcomings of using a single carbon capture technology. It also utilizes the cold energy inherent in LNG, which holds the potential for achieving lower energy consumption in CO2 capture. The process was simulated by Aspen Plus software, and sensitivity analysis was conducted on key parameters affecting system performance, such as liquefaction temperature, compression pressure, and permeate gas CO2 concentration. Experimental research was also carried out to validate the simulation results. The results indicate good consistency between simulation and experimental data, showing that the proposed process can provide liquid CO2 products that meet engineering or commercial application requirements. The carbon capture rate and product purity exhibit an inversely related trend with liquefaction temperature and compression pressure. In other words, as the liquefaction temperature decreases or the compression pressure increases, the carbon capture rate increases while product purity decreases. Under the premise of meeting the process’s target requirements (carbon capture rate greater than or equal to 85%, product purity greater than or equal to 90%), the lowest energy consumption for carbon capture in the process is 2.183 MJ/kg (the energy required to capture 1 kg of CO2 is 2.183 MJ). This study provides a novel approach to separate and recover CO2 from low-concentration CO2 flue gas.关键词：carbon capture;membrane separation;CO2 liquefaction;LNG cooling energy;coupling system- 42
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发布时间：2024-02-28 -
摘要：The safe and efficient liquid hydrogen refueling is the key to its transfer, storage and use. The research progress of liquid hydrogen refueling technology at home and abroad was reviewed from three aspects, including refueling modes, refueling structures and refueling processes. In normal gravity environment, both venting and non-venting refueling can be achieved through the rational design of refueling structures and processes. A typical unvented top-refueling process consists of three stages: initial rapid pressure rise, relatively stable refill and final rapid pressure rise, while unvented bottom-refueling has no obvious stage characteristics. For normal gravity refueling, different top-refueling configurations mainly affect the pressure and temperature changes in the receiving tank at the beginning of refueling, while different bottom-refueling configurations also significantly affect the flow field characteristics at the beginning of refueling. Different refueling processes mainly affect the refueling process through the mechanisms of initial flashing, wall boiling, liquid-phase evaporation, gas-phase condensation and gas-phase compression. For liquid hydrogen unvented refueling in a microgravity environment, the influence of refueling location and refueling structure on the refueling process is less than that of different refueling processes. For unvented refueling of liquid hydrogen in a microgravity environment, the effect of refueling location and refueling structure on the refueling process is less than the effect of different refueling processes. The degree of thermal deformation of the liner wall during refueling is positively correlated with its cooling degree, and the region of thermal stress concentration does not depend on the distribution of thermal deformation. In order to accelerate the safe and efficient liquid hydrogen refueling in a wider range of application scenarios, it is necessary to further deepen the theoretical analysis, simulation research and experimental research on the refueling process. At the same time, combined with economic efficiency, the systematic simulation research on the refueling process needs to be strengthened.关键词：liquid hydrogen refueling;refueling modes;refueling structures;refueling processes- 77
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发布时间：2024-02-28 -
摘要：Offshore wind power will develop towards deep-sea, large-scale and floating, while the energy storage and consumption of offshore wind power are challenges. Based on the interpretation of domestic and foreign literature in this field, it is found that offshore wind power ammonia production in deep-sea has the advantages of realizing large-scale energy storage and energy transfer from the sea to the land consumption end, and facilitating large-scale consumption and utilization in the downstream. Combined with the experience of technology and equipment in China’s offshore oil and gas industry, three innovative application scenarios for offshore wind power ammonia production in deep-sea: deep water semi-submersible ammonia production and storage platform, floating ammonia production, storage and unloading ship and floating offshore wind power platform were put forward, and the technical routes for ammonia production in different scenarios were summarized. It is concluded that large and medium-sized low-temperature and low-pressure ammonia synthesis technology is suitable for semi-submersible ammonia production and storage platform and floating ammonia production, storage and unloading ship, while small skid-mounted low-temperature and low-pressure ammonia synthesis technology and new electro-catalytic ammonia synthesis technology are more suitable for floating offshore wind power platform. The development status and difficulties of ammonia production technologies were analyzed. Finally, some suggestions on the future research direction of offshore wind power ammonia production in deep-sea were given.关键词：deep-sea;offshore wind power;green ammonia;synthesis ammonia- 58
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发布时间：2024-02-28 -
摘要：Natural gas steam reforming, as one of the most important hydrogen production processes, requires a significant amount of natural gas consumption. By optimizing the reforming process, it is possible to effectively reduce natural gas consumption. Using the chemical simulation software PROII, the conversion and shift reaction processes in the hydrogen production process from natural gas steam reforming were simulated. The error of the simulated value and the measured value of residual methane dry basis content (amount-of-substance fraction) is less than 1.5%, indicating that the simulation model is reliable and effective. Sensitivity analysis of the operating parameters in the conversion and shift reaction processes was also conducted based on this simulation model. The results show that when the water-carbon ratio (mole ratio) is 3.0, the outlet temperature of the conversion furnace is 820 ℃, and the outlet pressure is 1.2 MPa, the methane conversion rate of natural gas is higher (about 87%), and the fuel consumption is lower (about 70 m3/h). This is the optimal reforming condition and can be used as important process control indicators for actual production process.关键词：natural gas steam reforming;hydrogen;simulation analysis;water-carbon ratio;temperature;pressure- 62
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发布时间：2024-02-28
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