最新刊期
卷 49 ， 期 6 ， 2024
- “在工业催化剂资源化利用领域取得新进展，通过原位晶化方法成功制备了以SAPO-34分子筛为活性组分的MTO催化剂，实现了催化剂的循环利用，为工业失效催化剂的再生提供了有效解决方案。”
摘要：In order to solve the problem of resource utilization of industrially failed catalyst for methanol to olefins (MTO) and achieve the recycle of MTO catalysts, MTO catalysts with SAPO-34 molecular sieves as the active component were successfully prepared in a hydrothermal synthesis system using industrial failed MTO catalyst microspheres as raw materials through in-situ crystallization. XRD, SEM, N2 adsorption/desorption, XRF, NH3-TPD and infrared spectra of deuterated acetonitrile (CD3CN) were used to analyze the crystal structures, morphology characterizations, pore structures, elemental compositions and acidities of catalysts before and after in-situ crystallization. The catalytic performances of catalysts before and after in-situ crystallization in MTO reaction were evaluated in a fixed fluidized bed reactor. The research conditions were reaction temperature of 480 ℃, atmospheric pressure and methanol mass space velocity of 4 h-1, and raw material was pure methanol. The results show that compared with the catalyst before in-situ crystallization, the relative crystallinity of the catalyst after in-situ crystallization increases by 76%. And the specific surface area and content of B acid increase separately by 1.4 times and 1.1 times. In MTO reaction, the selectivity of dienes (ethylene and propylene) reaches the highest of 89.64%. Compared with the catalyst before in-situ crystallization, the selectivity of dienes increases by 3.3%. The contents (mass fraction) of dimethyl ether and heavy hydrocarbons such as C4 and C5+ are significantly reduced, and the catalyst after in-situ crystallization has excellent stability.关键词：failed catalyst;methanol to olefins;microspheres;in-situ crystallization- 34
- |
- 0
- |
- 0
发布时间：2024-06-28 - “最新研究进展显示，采用油包水微乳液法制备的Ni@SiO2核壳型催化剂，通过添加不同量的C16TAB后处理，成功制备了具有不同多孔结构的Ni@SiO2-xC16系列催化剂。这些催化剂在提高活性、稳定性以及抗积炭性能方面表现出显著优势，为解决催化剂性能提升问题提供了有效解决方案。”
摘要：Ni@SiO2 core-shell catalysts were prepared by oil-in-water microemulsion method. Adding a gradient amount of substance of cetyltrimethylammonium bromide (C16TAB) for post-treatments, Ni@SiO2-xC16 catalysts with distinct porous structures were prepared. By characterization techniques including N2 adsorption/desorption, XRD, TEM, H2-TPR, XPS and Raman spectroscopy, the catalysts were analyzed, and the effects of pore structures on Ni@SiO2-xC16 shell on the activity, stability and anti-coking performance of catalysts were investigated. The results indicate that Ni@SiO2-xC16 has a larger specific surface area and more abundant pore structures, which help to improve the dispersion of Ni particles, limit the size of Ni particles to less than 5 nm and strengthen the interaction between Ni particles and supports. In a 50 h stability test, Ni@SiO2 has a low initial CH4 conversion rate (68.5%) and weak stability, but after C16TAB post-treatment, Ni@SiO2-2C16 and Ni@SiO2-3C16 show high initial CH4 conversion rates (both about 84.1%) and high stability, and n(H2)/n(CO) in products exceeds 0.97 and almost no deactivation occurred. After further study, it is found that the type of carbon species in Ni@SiO2-xC16 changes from a large amount of graphite carbon that is difficult to eliminate to a small amount of disordered carbon that is easy to remove. Therefore, the performances of anti-coking and anti-sintering of Ni@SiO2-xC16 are improved.关键词：methane dry reforming;Ni@SiO2;porous structures;anti-coking performance- 10
- |
- 0
- |
- 0
发布时间：2024-06-28 - “最新研究揭示了甲醇合成催化剂失活原因，通过X射线荧光光谱等技术对催化剂进行表征分析，发现催化剂出现径向强度减小、粉化、铜晶粒尺寸增大等现象，为延长催化剂使用寿命提供解决方案。”
摘要：The deactivation of methanol synthesis catalysts is one of the important factors leading to the shutdown of methanol synthesis units, which seriously affects the economic benefits of production enterprises. Characterization analysis was conducted on catalyst samples from two methanol factories to investigate the reasons for their deactivation, including X-ray fluorescence spectroscopy, X-ray diffraction, infrared spectroscopy, physical adsorption and inductively coupled plasma emission spectroscopy. The results show that after about two years of industrial use, the catalysts exhibite phenomena such as decreased radial strength, pulverization, increased copper grain size, decreased specific surface area and enrichment of harmful impurity elements (sulfur and iron). The maximum grain size of copper in the deactivated catalyst can reach 32.72 nm, and the corresponding specific surface area decreases from 102.3 m2/g to the lowest 16.0 m2/g. The sulfur and iron contents (mass fraction) increase from less than 0.05% and 362 × 10-6 to the highest 0.36% and 2629 × 10-6, respectively. The catalysts collected from two factories exhibit different deactivation characteristics, and targeted measures need to be taken to extend the service life of the catalysts.关键词：methanol;catalysts;deactivation;copper grain- 14
- |
- 0
- |
- 0
发布时间：2024-06-28 - “在甲醇制烯烃工艺领域，专家综述了分子筛催化剂的晶粒尺寸、孔道和酸性质调控进展，探讨了二甲醚制烯烃反应特征，为提高低碳烯烃选择性和抑制催化剂积碳提供解决方案。”
摘要：Methanol to olefins (MTO) process is widely used in industry, but the molecular sieve catalysts used in the process still have some issues, such as high selectivity of C4+ products (butene, butane, etc.) and easy carbon deposition and deactivation. Therefore, it is necessary to further explore methods to enhance the selectivity of low carbon olefins and inhibit carbon deposition. The research progress on grain size regulation, pore regulation and acid property regulation of ZSM-5 and SAPO-34, and the reaction characteristics of dimethyl ether to olefins (DTO) in molecular sieve system were reviewed. The olefins formation mechanism in the hydrocarbon pool mechanism was summarized, and the potential of using mordenite (MOR) in MTO and DTO reaction systems was briefly discussed, such as its potential to further regulate the distribution of low carbon olefins in the final products, and it is anticipated that this can help regulate the distribution of low carbon olefins in the final products. The reaction mechanisms for MTO and DTO reactions remain undetermined, and current catalyst modification schemes can provide slight improvements in product selectivity of low carbon olefins and delay carbon deposition by mesoporous structures. In the future, building composite catalysts is a direct solution to solve the problems of low selectivity ratio of ethylene and propylene and easy carbon deposition in industrialization.关键词：methanol;dimethyl ether;olefin;catalyst modification;ZSM-5;SAPO-34- 33
- |
- 0
- |
- 0
发布时间：2024-06-28 - “最新研究进展显示，甘氨酸合成方法在农药、医药、食品和饲料等领域具有重要应用价值。专家深入分析了化学合成和生物合成方法的优缺点，并展望了未来发展方向。”
摘要：As an important amino acid, glycine is widely used in pesticide, medicine, food and feed, etc. It is of great practical significance to study the synthesis method of glycine. The research progress of glycine chemical synthesis methods (chloro-acetic acid ammonolysis method, Strecker method, aminoacetonitrile method, hydantion method, alcohol ammoxidation method and methyl hydroxyacetate method, respectively) and biosynthesis methods (using aminoacetonitrile, carbon dioxide + ammonia as raw materials, respectively) were reviewed. The advantages and disadvantages of each method were analyzed and compared. The future development of glycine synthesis methods was also prospected.关键词：glycine;chemical synthesis;biosynthesis- 28
- |
- 0
- |
- 0
发布时间：2024-06-28 - “最新研究发现，通过调节介孔SiO2材料孔结构和催化剂酸碱性质，可显著提高乙醇直接转化制丁二烯的效率。ZnZr/KIT-6催化剂在350℃和1.23 h-1条件下，实现91.2%的乙醇转化率和53.5%的丁二烯选择性，为减少化石资源依赖和环境问题提供有效策略。”
摘要：Direct conversion of ethanol to butadiene is an effective strategy to reduce dependence on fossil resources and alleviate environmental problems. The development of novel catalysts can increase the production of butadiene. By adjusting the pore structure of mesoporous SiO2 materials, the rapid transfer of ethanol and important intermediates between the host and guest molecules can take place, and the adjustment of the acid-base properties and the synergistic effect of the active centers of catalysts can improve the catalytic performance of catalysts. A series of mesoporous SiO2 loaded Zn and Zr catalysts with different pore structures (ZnZr/SiO2, ZnZr/MCF, ZnZr/SBA-5 and ZnZr/KIT-6) were prepared by a wet impregnation method. The performances of catalysts for direct conversion of ethanol to butadiene were evaluated, and the synergistic effects of each active center of the catalysts and the influence of acid-base properties on the catalytic performance were revealed by various characterization techniques. The characterisation results show that the pore structure can effectively modulate the acid-base properties of the catalysts, and the mesostructured porous foam (MCF) can promote the interaction of Zn species with silanol to form strong Lewis acid sites. ZnZr/KIT-6 catalyst exhibits moderate acid properties because the interactions of Zr species with silanol on KIT-6 form moderate strength Lewis acid sites and KIT-6 inhibits the interaction of Zn species with silica hydroxyls to form strong acidic sites. In ZnZr/KIT-6 catalyst, Zn species mainly exist as ZnO, which is favourable for the dehydrogenation of ethanol to acetaldehyde. Compared to ZnZr/SBA-15 catalyst, ZnZr/KIT-6 catalyst has an increased amount of weak bases and a decreased amount of strong bases with a weaker base strength. Moderate acid and weak base properties are beneficial for the aldol condensation reaction in the direct conversion of ethanol to butadiene, so in the direct conversion of ethanol to butadiene reaction catalysed by ordered mesoporous SiO2 loaded Zn and Zr catalysts, ZnZr/KIT-6 catalyst shows the highest ethanol conversion rate and butadiene selectivity at a temperature of 350 ℃ and a reaction space velocity of 1.23 h-1, which is 91.2% and 53.5%, respectively, and the butadiene space time yield is up to 0.35 g/(g·h).关键词：ethanol;butadiene;mesoporous SiO2;ZnZr/KIT-6;aldol condensation;acid-base properties- 11
- |
- 0
- |
- 0
发布时间：2024-06-28 - “最新研究突破：煤焦-Ni复合物在甲烷干重整反应中显著提升转化率，同时反应后形成的碳材料在超级电容器电极材料中展现优异性能，为温室气体转化和能源回收利用开辟新途径。”
摘要：Dry reforming of methane (DRM) can convert two greenhouse gases CH4 and CO2 into syngas, which has significantly environmental and economic benefits. However, the high reaction temperature and carbon deposition during the DRM process can easily cause the deactivation of metal catalysts such as Ni, limiting its application in industry. At present, coal pyrolysis char (referred to as “coal char”) has good potential as supports of high effective Ni-based catalysts. In order to improve performance of DRM reaction and promote the utilization of coal char, a coal char-Ni complex was designed and prepared with K2CO3 as an additive. The DRM reaction performance, surface and structural properties of the formed carbon materials from the coal char-Ni complex after the reaction and its performance as supercapacitor electrode materials were investigated. The results demonstrate that the initial CH4 and CO2 conversion rates reach 71% and 72%, respectively when m(coal char):m(K2CO3):m(Ni) = 1.00:1.00:0.05 and the temperature is 850 ℃. After optimizing the reaction conditions (including Ni loading amounts, the temperature and reaction time of DRM reaction), the formed carbon materials from the spent char-Ni complex, serving as supercapacitor electrodes, can show good electrochemical properties. CC-2 has specific capacitances of 136 F/g at a scanning rate of 5 mV/s and 143 F/g at a current density of 1 A/g. This study provides a potential path for the synergistic conversion of DRM and coal char and recycling of the spent carbon materials (catalysts or supports of catalysts in the reaction).关键词：dry reforming of methane;coal char;Ni;electrode materials;specific capacitance- 26
- |
- 0
- |
- 0
发布时间：2024-06-28 - “在生物质能源领域，科研团队采用尿素沉淀法和程序升温还原法制备了水滑石基Ni/Al2O3催化剂，并通过X射线衍射分析了催化剂及其前驱体的物相组成。研究发现，该催化剂在水-甲醇混合溶剂中对玉米秸秆加氢裂解反应具有优异的催化性能，转化率接近100%，二元醇产率达到38.8%，芳香族单体产率为13.6%。这一成果为生物质高附加值化学品的制备提供了有效途径。”
摘要：Biomass is one of the most potential alternatives of fossil fuel. The production of high value-added chemicals from biomass is an effective way to realize the diversified application of biomass. A hydrotalcite-derived Ni/Al2O3 catalyst was prepared via urea precipitation and temperature-programmed reduction, which was analyzed with X-ray diffraction (XRD). The catalytic performance of Ni/Al2O3 catalysts hydrocracking of corn stover was investigated in water-methanol mixed solvent. The results show that Ni/Al2O3 catalyst exhibits good catalytic performance, and the corn stover conversion rate is up to 100%, and the diols yield is 38.8%, and the phenolic monomers yield is 13.6% under the optimum conditions (V(H2O):V(CH3OH) = 7:3, 240 ℃ and 3.0 MPa H2). V(H2O):V(CH3OH) and temperature show notable impacts on corn stover conversion rate and small yields of molecule products. Ni/Al2O3 catalyst and atmosphere influence small molecule products as well as products distribution. Cyclic test of the catalyst after one cycle reveals that the yields of diols and aromatic monomers decrease to 10.8% and 5.4%, respectively. Based on the results of Raman spectroscopy, it is speculated that the decrease in catalyst activity may be due to the formation of carbon deposits on the catalyst surface. Furthermore, it can be inferred that Ni/Al2O3 catalyst shows crucial role in the stabilization of active intermediates by analyzing the generation pathways of diols and aromatic monomers.关键词：corn stover;hydrocracking;Ni/Al2O3 catalyst;diols;aromatic monomers- 18
- |
- 0
- |
- 0
发布时间：2024-06-28 - “最新研究显示，天然气化工副产氢经提质升级，可转化为高品质氢，创新应用于氢燃料电池汽车，突破传统化工用途，为氢能产业发展提供新动力。”
摘要：The conversion of by-product hydrogen form natural gas chemical industry from traditional chemical applications to hydrogen energy applications can achieve upgrading of by-product quality and is beneficial for the development of the hydrogen energy industry. The carbonyl synthesis gas and acetylene tail gas from natural gas chemical industry are separated and purified to produce high-quality hydrogen, which can be innovatively applied to hydrogen fuel cell vehicles. It was proposed that the by-product hydrogen could be upgraded to various high-quality hydrogen that meets the technical requirements of national standards to meet the application needs of industry, transportation, energy and construction hydrogen, and expand the application field of hydrogen energy. In response to the current difficulties of storage and transportation bottlenecks and cost constraints of hydrogen energy affecting its large-scale applications, it was proposed that natural gas chemical enterprises could also synthesize liquid ammonia from the by-product hydrogen to transform and apply it through hydrogen-ammonia fusion based on the characteristics of liquid ammonia as hydrogen storage medium and zero carbon fuel, as well as the obvious advantages of liquid ammonia compared to gas hydrogen and liquid hydrogen storage. What’s more, the application scenarios and development prospects of liquid ammonia in traditional fuels, ammonia fuel cells and ammonia catalytic cracking for hydrogen production were analyzed. By-product hydrogen from natural gas chemical industry can break through traditional chemical applications and transform into hydrogen energy applications with good development prospects, playing a positive role in the field of new energy.关键词：natural gas chemical industry;hydrogen;hydrogen energy;hydrogen-ammonia fusion;liquid ammonia;ammonia fuel- 20
- |
- 0
- |
- 0
发布时间：2024-06-28 - “固体氧化物电解技术在制氢和二氧化碳转化领域的研究取得新进展，通过耦合化工过程制化学品，推动了与传统化工产业的深度融合，为能源体系的清洁高效发展提供了新思路。”
摘要：Solid oxide electrolysis cell (SOEC) technology can convert thermal energy and electrical energy into chemical energy. Due to its unique advantage of effectively utilizing high-temperature waste heat, it can help the energy system achieve clean and efficient development and has been developed for applications in hydrogen production and carbon dioxide conversion. However, the high cost and insufficient integration with traditional industries limit the widespread adoption of this technology. Coupling SOEC technology with chemical processes for chemical production can not only achieve multifunctionality of SOEC-based energy conversion systems but also improve the economic viability of related projects. Focusing on the forefront of SOEC technology development, the research progress in coupling SOEC technology with chemical processes for chemical production (methanol, ammonia, methane, ethylene, etc) was summarized, the characteristics of relevant path processes were analyzed, and breakthroughs in related application scenarios at home and abroad were reviewed. The aim is to promote the deep integration of SOEC technology with traditional chemical industries and explore potential applications of SOEC.关键词：high-temperature solid oxides;electrolysis;chemicals;chemical industry- 21
- |
- 0
- |
- 0
发布时间：2024-06-28 - “在费托合成油品转化领域，科研人员通过晶种法合成含磷ZSM-5分子筛，显著提升了其水热稳定性，为高辛烷值汽油生产提供了新方案。”
摘要：In the fluidized bed system for the conversion of Fischer-Tropsch synthetic oil to high octane gasoline, the presence of water vapor can easily lead to the irreversible hydrothermal inactivation of ZSM-5 zeolites, but the introduction of phosphorus can improve the hydrothermal stability of ZSM-5 zeolites. Phosphorus-containing ZSM-5 zeolites were directly hydrothermal synthesized by seeding method (HS-P-Z5) in an amine-free system, and compared with phosphorus-containing ZSM-5 zeolites obtained by conventional impregnation method (IM-P-Z5). The properties of ZSM-5 zeolites before and after hydrothermal treatment were characterized by XRD, SEM, N2 adsorption/desorption, et al. Water washing experiment was conducted to investigate the loss of phosphorus. The aromatization performance of ZSM-5 zeolites was evaluated using 1-octene as probe molecule. The results show that HS-P-Z5 has higher intensity of characteristic diffraction peaks, more micropore structures and acid content than IM-P-Z5. The results of water washing experiment and NMR characterization show that HS-P-Z5 has more stable phosphorus and aluminum structures, and the phosphorus species are not easy to be washed away, making it more hydrothermal stable, and can retain more microporous structures and strong acid sites of zeolites after hydrothermal treatment. HS-P-Z5-ST (ST represents hydrothermal treatment) has the highest aromatics selectivity, with the aromatics selectivity of 23.1% at the reaction time of 730 min, higher than IM-P-Z5-ST (18.4%) and Z5-ST (11.2%).关键词：phosphorus-containing ZSM-5 zeolites;seeding method;aromatization;hydrothermal stability- 37
- |
- 0
- |
- 0
发布时间：2024-06-28 - “在固体氧化物电解槽（SOEC）领域，专家建立了二维模型，探索了逆水汽反应（RWGS反应）在合成气制备中的作用，为提高CO2转化率提供解决方案。”
摘要：Solid oxide electrolysis cell (SOEC) can convert H2O and CO2 into syngas (H2 and CO) through co-electrolysis, thereby achieving the capture and utilization of CO2. However, in addition to electrochemical reactions, the reverse water gas shift (RWGS reaction) of the reaction gas at high temperatures also has a certain impact on the process. In order to investigate the role of RWGS reaction in synthesis gas preparation, a two-dimensional model of button-type SOEC for syngas preparation in open circuit state was established. The effects of inlet gas composition and operating temperature on RWGS reaction in the support layer of SOEC in open circuit state were studied. The simulation results of the model were compared and verified with experimental data to ensure the reliability of the model. The results indicate that the content (mole fraction , the same below) of reducing gas H2 in the inlet gas is the primary factor affecting the RWGS reaction rate. The higher the H2 content, the faster the RWGS reaction rate. When the H2 content is 30%, the CO2 conversion rate is above 29%. When the H2 content is 10%, the CO2 conversion rate is only 9% to 10%. In addition, when the H2 content is constant, the reaction rate of RWGS is mainly positively correlated with the CO2 content. Increasing the CO2 or H2 content in the inlet gas can improve the CO2 conversion rate in the open circuit state to varying degrees. A higher operating temperature is conducive to faster RWGS reaction, and under a constant H2 content, the higher the CO2 content in the inlet gas, the greater the rate of change in RWGS reaction rate.关键词：solid oxide electrolytic cell;co-electrolysis model;reverse water gas shift reaction;syngas- 16
- |
- 0
- |
- 0
发布时间：2024-06-28 - “在煤气化清洁利用领域，研究人员深入探讨了介孔氧化硅分子筛负载金属氧化物脱硫剂的构效关系，发现金属掺杂复合改性可提高脱硫活性，为高性能脱硫剂设计提供理论依据。”
摘要：Coal gasification is a core technology for the clean and efficient utilization of coal. However, the hydrogen sulfide (H2S) contained in the gasified crude gas will corrode the equipment and pollute the environment, so it is necessary to purify and desulfurize the gas. Mesoporous silica molecular sieves have the characteristics of large specific surface area, large pore volume, and ordered mesoporous structure. As the carrier of the metal oxide, it can promote the dispersion of the metal oxide,provide a large number of reaction active sites for the desulfurization reaction, and reduce mass transfer resistance. The structure-activity relationship of desulfurizer is one of the key scientific problems in gas desulfurization technology. However, for supported high-temperature coal gas desulfurizer, this relationship is superimposed and influenced by multiple factors such as mesoporous silica zeolite, types of desulfurization active components, modification methods of desulfurizers, and desulfurization conditions, so it is extremely challenging to clarify its essence. Firstly, the pore structure characteristics of different mesoporous silica molecular sieves were discussed, and the desulfurization behavior differences of mesoporous silica molecular sieves loaded with active components were analyzed. It is found that desulfurizers with a carrier possessing abundant pore structure and thicker pore walls exhibit better performance in high-temperature desulfurization processes. The structural control strategies of metal oxide supported desulfurizers based on zinc, manganese and iron in recent years and their effects on desulfurization performance were analyzed. It is evident that the desulfurization activity of the active components can be enhanced by metal doping. The sulfur release mechanism, sulfur release pattern and suppression means in the desulfurization process were discussed. The introduction of catalytic carbonyl sulfur (COS) hydrogenolysis agent in the desulfurizer can effectively inhibit the sulfur emission behavior. The review can provide a theoretical basis for the structural design and functional construction of high-performance and high-temperature desulfurizers.关键词：high-temperature coal gas;desulfurization;mesoporous silica molecular sieves;metal oxides;sulfur release;carbonyl sulfide- 17
- |
- 0
- |
- 0
发布时间：2024-06-28 -
Process research on CH4/N2 pressure swing adsorption based on carbon molecular sieve adsorbents AI导读
“在天然气提纯领域，研究人员开发了一种以碳分子筛为吸附剂的变压吸附技术，通过优化工艺条件，成功将CH4含量提高至95%以上，为天然气管道输送提供了高效解决方案。”
摘要：Pressure swing adsorption (PSA) is a mature technology, which has been widely used in separation of CH4/N2 mixture gas. Existing researches mostly focus on the separation and purification of mixture gas with low (10%~50%) CH4 content (volume fraction, the same below). Therefore, it is necessary to develop a PSA technology with the carbon molecular sieve as the main adsorbent for CH4/N2 mixture gas with high CH4 content (≥ 70%). Carbon molecular sieves with high separation coefficient and high adsorption capacity were screened by PSA static experiment and single-tower simulation experiment, and the multiple-towers simulation experiment was used to establish the best process conditions. The best process conditions were obtained by changing parameters such as adsorption times, adsorption pressure and process steps. The results show that, the best multiple-towers simulation process conditions are process steps of 5-1-2/V, adsorption pressure of 0.5 MPa with 70 s, two stages of equalizing pressure, the first equalization pressure pressurization time of 60 s, the second equalization pressure pressurization time of 10 s, inverse releasing to normal pressure with 20 s and vacuum to -0.092 MPa with 70 s. Under the optimal conditions, the CH4 concentration of product gas can be increased to the natural gas pipeline transmission requirements (CH4 content ≥ 95% and N2 content ≤ 5%), and the yield of CH4 is 68%.关键词：pressure swing adsorption;carbon molecular sieves;CH4/N2 separation;multiple-towers simulation experiment- 17
- |
- 0
- |
- 0
发布时间：2024-06-28 - “最新研究揭示了大分子促进剂对氢气水合物稳定性的影响，为氢气储存和运输提供了新思路。”
摘要：The temperature and pressure conditions for the formation of pure hydrogen hydrates are extremely harsh (low temperature and high pressure), limiting their industrial applications, whereas the temperature and pressure conditions for the formation of hydrogen and methane mixture hydrates are relatively mild. The effects of four macromolecular promoters, cycloheptanone (C7H12O), methylcyclohexane (C6H11-CH3), 1,1-dimethylcyclohexane (1,1-C8H16) and 1,2-dimethylcyclohexane (1,2-C8H16), on the stability of H-type pure hydrogen hydrates and hydrogen and methane mixture hydrates were investigated by means of molecular dynamics simulations using a thermostatic constant pressure (NPT) system. The results show that the cage stability of H-type hydrates with the application of the four macromolecular promoters is, in descending order, 1,1-C8H16, 1,2-C8H16, C6H11-CH3, and C7H12O. The mixture of hydrogen and methane is able to greatly moderate the thermodynamic conditions (temperature increases and pressure decreases) compared to that of pure hydrogen. The two isomers (1,1-C8H16 and 1,2-C8H16) show large differences in thermodynamic conditions between them as macromolecular promoters. In pure hydrogen hydrate, both isomers require similar temperature condition (270 K) as macromolecular promoters, while 1,1-C8H16 requires lower pressure condition (60 MPa) as a macromolecular promoter than 1,2-C8H16 (100 MPa). In hydrogen and methane mixture hydrates, 1,1-C8H16 requires higher temperature condition (270 K) than 1,2-C8H16 (260 K) and lower pressure condition (20 MPa) than 1,2-C8H16 (40 MPa) as a macromolecular promoter.关键词：H-type hydrates;macromolecular promoters;bi-guest small molecules;hydrogen storage;molecular dynamics- 18
- |
- 0
- |
- 0
发布时间：2024-06-28 - “在二氧化碳捕集与封存领域，研究者通过实验发现，纳米氧化锌和十二烷基硫酸钠的添加能显著提高CO2水合物生成速率，为CO2捕集和封存提供理论指导。”
摘要：The hydrate method for capturing and storing carbon dioxide (CO2) has the advantages of high gas storage capacity and low cost, but the long induction time and slow formation rate of CO2 hydrate (“hydrate” for short) limit its application. To promote hydrate formation, the effects of nano zinc oxide (ZnO) and sodium dodecyl sulfate (SDS) on hydrate formation were investigated by constant volume method. The results indicate that under certain conditions, increasing the initial pressure and introducing mechanical stirring can promote hydrate formation. Additionally, the addition of either nano ZnO or SDS alone can significantly reduce the induction time. Specifically, under the conditions of ZnO mass fraction of 0.06% and 275.65 K, the optimal values of initial pressure and stirring rate are determined to be 4.5 MPa and 500 r/min, respectively. Under the conditions of 3.5 MPa, 275.65 K and 300 r/min, the induction time of the system adding nano ZnO with the mass fraction of 0.10% and particle size of 50 nm (ZnO-50) is 41.6 min, which is 91.5% shorter than that of the pure water system (487.4 min). When the mass fraction of ZnO-50 in the system is 0.06%, the total gas consumption is 0.903 mol, which is 103.4% higher than that of the pure water system (0.444 mol). The promotion effect of increasing SDS mass fraction on total gas consumption gradually increases, reaching a maximum (1.027 mol) when the mass fraction of SDS in the system is 0.10%, which is 131.3% higher than that of the pure water system. Constructing a synergistic system with the mass fraction of 0.10% SDS and 0.02% ZnO-50, the total gas consumption (1.045 mol) remains relatively constant under equilibrium pressure, but the hydrate formation rate can be significantly accelerated. The gas consumption at half-time of the experiment (reaction for 5 h) reaches 0.924 mol, accounting for 88.4% of the total gas consumption over the entire experiment (reaction for 10 h), which is significantly higher than the corresponding data (63.7% and 48.5%, respectively) when using ZnO-50 with mass fraction of 0.02% and SDS with mass fraction of 0.10% alone. The research findings can provide theoretical guidance for the application of hydrate technology in CO2 capture and storage.关键词：hydrate;nano zinc oxide;sodium dodecyl sulfate;induction time;gas consumption- 36
- |
- 0
- |
- 0
发布时间：2024-06-28
- 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：93096 Visits Today：11
0