生物质催化气化合成甲醇

生物质合成甲醇是CO2零排放的能量转换技术，避免了由于燃烧化石能源带来的温室气体效应问题。文章对生物质合成气的制备、净化、化学当量比调整等技术进行了介绍和分析，对生物质合成甲醇的经济性和前景进行了分析评价。     

生物质合成气合成甲醇

在高压微型反应装置上进行了生物质合成气合成甲醇的实验研究。利用组成为V(H2)/V(CO)/V(CO2)/V (N2)=50/25/20/5的富CO2原料气考察了不同温度、压力和空速条件下甲醇的时空产率、甲醇和水的选择性等指 标。结果表明,在所考察的范围内,温度、压力和空速对甲醇的产率和选择性都有影响。在反应压力为4．6MPa, 空速为7000h-1时,时空产率的最大值为0．69g/(mL·h),甲醇的选择性范围为93％-97．2％。和富CO的原料气 相比,利用富CO2的生物质合成气合成甲醇,甲醇的时空产率和选择性都有所下降,时空产率下降的幅度在 10％-30％之间,选择性的下降幅度在2％-8％之间。通过控制适宜的操作条件,可降低甲醇的产率和选择性 的下降幅度。     

秸秆燃气合成甲醇的优化试验研究

以秸秆合成气为原料,在直流流动等温积分反应器中,使用国产C301铜基催化剂,在5 MPa压力下,进行催化合成甲醇的反应温度、秸秆合成气配比、合成气进口流量的优化试验研究.试验获得了玉米秸秆合成气合成甲醇的最佳反应条件,为生物质（秸秆）气制甲醇中试研究提供科学和实用的参考依据.     

秸秆合成气催化合成甲醇催化剂优化试验研究

生物质能是一种可再生能源,为了研究秸秆类生物质转化为燃料甲醇以有效地利用生物质能,采用热化学方法在下吸式固定床气化炉中生产低热值燃气,对该燃气进行脱硫、脱氧、焦油催化分解、纯化、配氢等优化试验,制备出秸秆合成气。在直流流动等温积分反应器中进行了催化合成甲醇的试验,在235℃和5MPa条件下进行了催化剂种类及粒度对合成甲醇的影响试验。试验结果表明:合成甲醇的适宜催化剂型号为C301,最优化颗粒粒度为0.833mm×0.351mm,该研究为生物质(秸秆)气催化合成甲醇的深入研究提供了基础数据。     

生物质合成甲醇的热力学性质研究

采用热化学方法,将玉米秸秆裂解为生物质燃气,制备出甲醇合成气;在C301铜基催化剂的作用下,在直流流动等温积分反应器中,对玉米秸秆合成气催化合成甲醇进行了试验研究.运用SHBWR状态方程,计算了加压下秸秆合成气合成甲醇反应体系的密度及状态方程参数;在一定温度和压力条件下,计算了不同组成秸秆合成气合成甲醇反应体系的总反应热△HT P、平衡常数Kf1、Kf2、Kp1、Kp2及平衡体系各组分的浓度,为生物质(秸秆)气催化合成甲醇工业设备的设计提供了基础研究数据.     

生物质(秸秆)气合成燃料甲醇的可行性研究

生物质是可再生能源的重要组成部分,生物质能的高效利用,对解决能源、生态环境将起到十分积极的作用.介绍主要利用生物质气做合成燃料甲醇的可行性方面的研究.     

生物质(秸杆)气合成燃料甲醇的可行性研究

生物质是可再生能源的重要组成部分,生物质能的高效利用,对解决能源、生态环境将起到十分积极的作用。介绍主要利用生物质气做合成燃料甲醇的可行性方面的研究。     

生物质气合成二甲醚实验研究

采用水蒸汽气化木屑制备生物质气,在下游的重整反应器内,通过两段催化重整焦油,焦油裂解率高得96.70%.在双功能催化剂JC207/HZSM-5催化剂上,对生物质气合成二甲醚进行了实验研究.利用原生物质气以及脱碳生物质气考察了不同温度、压力和空速对合成二甲醚的影响.结果表明,在260℃,4 MPa、2400 L/(kgcat·h)条件下,原生物质气的CO单程转化率达到67.95%,单位质量催化剂的最大二甲醚时空收率0.338g/(gcat·h).脱碳生物质气的CO单程转化率达到75.52%,单位质量催化剂的最大二甲醚时空收率0.583g/(gcat·h).     

生物质气化合成甲醇二甲醚技术现状及展望

综述了国内外生物质气化合成甲醇技术的研发现状,介绍了国外几种生物质气化合成甲醇工艺,包括美国的Hynol工艺和NREL项目,瑞典的Bal-Fuels项目、BioMeet项目和造纸黑液气化制汽车燃料技术,以及日本三菱重工的MHI项目。讨论了生物质气化合成甲醇技术与我国联醇工艺的结合,对我国开发生物质制甲醇技术提出了建议。     

三种生物质气催化制甲醇的比较

比较了由生物质衍生的3种气体：含N_2且未调节C／H比的气体(A)、不含N_2但未调节C／H的气体(B)、不含N_2且调节C／H的气体(C)催化合成甲醇的性能。在P=4MPa、r=260℃、SV=5280h~(-1)下,与气体(C)比,气体(A)和气体(B)所得甲醇产率分别下降47.2％和25.5％,甲醇浓度分别下降1.4％和1.6％。反应温度对含CO_2的气体(A)和(B)合成甲醇的性能有重要影响,在260℃时甲醇产率和浓度都达到最佳值。大量CO_2的存在导致甲醇浓度的下降,CO_2含量越高,所得甲醇的浓度越低。     

Effect 3A and 5A molecular sieve on alcohol-assisted methanol synthesis from CO2 and H2 over Cu/ZnO catalyst

Low-temperature methanol synthesis from CO₂ and H₂ was carried out using ethanol as a catalytic solvent. The alcohol-assisted method reduced synthesis temperature and enhanced methanol yield (33.80%) at 150 °C (5.0 MPa, Cu/ZnO catalyst). However, ethyl acetate and water were generated as byproducts from the reaction. The byproducts formed azeotrope mixture with methanol and led to a complex product purification. Therefore, in this study, molecular sieves (MS) were introduced to adsorb the byproducts. The effect of different MS (3A and 5A) was studied. It was found that MS helped enhancing methanol yield. The highest methanol yield (42.8%) was obtained when adding MS_3A to adsorb water. The MS_5A could separate methanol and ethyl acetate, providing high methanol purity. The effect of operating conditions was also investigated. When reducing temperature to 130 °C, methanol yield decreased but methanol selectivity (>98%) significantly increased. Controlling temperature and using MS could help enhance the yield and selectivity of methanol.     

Exergy analysis of renewable light olefin production system via biomass gasification and methanol synthesis

The conceptual light olefin production system from biomass via gasification and methanol synthesis was simulated and its thermodynamic performance was evaluated through exergy analysis. The system was made up of gasification, gas composition adjustment, methanol synthesis, light olefin synthesis, steam & power generation and cooling water treatment. The in-depth exergy analysis was performed at the levels of system, subsystem and operation component respectively. The gasifier and the tail gas combustor were the main sources of irreversibility with exergy destruction ratios of 17.0% and 16.8% of the input exergy of biomass. The steam & power generation subsystem accounted for 43.4% of the overall exergy destruction, followed by 41.0% and 5.69% in the subsystems of gasification and gas composition adjustment respectively. The sensitivity evaluation of the operation parameters of gasifier indicates that the system efficiency could be improved by enhancing syngas yield and subsequent yield of light olefins. The overall exergetic efficiency of 30.5% is obtained at the mass ratios of steam to biomass and O₂-rich gas (95 vol%) to biomass (S/B and O/B) of 0.26 and 0.14 and gasification temperature at 725 °C.     

Low-temperature alcohol-assisted methanol synthesis from CO2 and H2: The effect of alcohol type

Carbon dioxide (CO₂) conversion to higher-value products is a promising pathway to mitigate CO₂ emissions. Methanol is a high-value-chain chemical in industries that can be produced through CO₂ hydrogenation, which is an exothermic reaction. Due to thermodynamic limitations, a typical synthesis temperature between 250 °C and 300 °C results in a low conversion of CO₂ at equilibrium. To enhance the CO₂ conversion, high pressures of 50–100 bar are required, which inevitably causes the process to be energy-intensive. In this study, an alternative method called alcohol-assisted methanol synthesis is investigated. In this method, alcohol is used as a catalytic solvent and helps decrease the reaction temperature and pressure (150 °C and 50 bar) and significantly increases methanol yield. Ethanol is used as the alcohol due to its reactivity, providing a high methanol yield (47.80%) with 63.93% CO₂ conversion and 67.54% methanol selectivity. However, due to unwanted side reactions, ethanol generates ethyl acetate as a byproduct that forms an azeotrope with methanol, leading to difficulty in product purification. The effects of alcohol type (molecular weight and structure), including ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso-butanol, tert-butanol and 1-pentanol, on CO₂ conversion, methanol yield and byproducts are investigated. It is found that smaller-molecule alcohols provide a higher methanol yield. Moreover, n-alcohols provide a higher methanol yield than branched alcohols, and the byproducts of the reaction with n-alcohols do not form an azeotrope with methanol. Therefore, 1-propanol is compared with ethanol providing 26.55% methanol yield, 69.02% CO₂ conversion and 70.82% methanol selectivity.     

Effect of CuO/ZnO catalyst preparation condition on alcohol-assisted methanol synthesis from carbon dioxide and hydrogen

CuO/ZnO catalysts are synthesized using a co-precipitation method with different precipitation temperatures (298–353 K) and pH values (5–9). A conventional precipitation is compared to an ultrasonic-assisted precipitation at each precipitating temperature. Methanol is directly synthesized from CO₂ and H₂ (1:3 mol ratio) through an alcohol-assisted reaction (423 K, 5 MPa, 24 h) by using different alcohols (ethanol, propanol and butanol) as a medium. There are two parts for the challenge of this research, including the preparation of CuO/ZnO catalysts using an ultrasonic-assisted precipitation and, methanol synthesis through an alcohol-assisted method. It is found that the precipitation temperature and pH value significantly affect the catalyst properties and the reaction activity. An ultrasonic irradiation helps facilitate the crystalline phase formation and decrease precipitation temperature. The highest yield of methanol is obtained when CuO/ZnO is precipitated at 333 K from the conventional precipitation (31%) while it is at 313 K from the ultrasonic-assisted precipitation (32%). In addition, the different type of alcohol strongly affects methanol yield and CO₂ conversion. The use of larger alcohol molecules offers higher CO₂ conversion but lower methanol yield.     

Dry anaerobic fermentation of agricultural residues

The dry anaerobic fermentation plays an important role in the field of bioengineering, especially in the production of energy (biogas) and organic fertilizer. Meanwhile the pollution effect of the solid wastes are decreased. Dry anaerobic fermentations of different organic solid wastes were studied. These included cotton stalks, treated cotton stalks, corn stalks, rice straw, and water hyacinth. The effect of the initial solid concentration, temperature, starter, and buffer additives on dry anaerobic fermentation on biogas production rate and yield has been studied.     

生物质催化热裂解技术的研究进展

生物质催化裂解是生物质热化学转化的一种重要途径。综述了生物质催化热裂解技术使用的反应器、催化剂类型,以及催化热裂解过程中热裂解温度、吹扫气、升温速率、生物质原料等条件的影响,展望了生物质催化热裂解技术的发展趋势。     

A novel cascade membrane reactor concept for methanol synthesis in the presence of long‐term catalyst deactivation

In this study, a dynamic model for a novel cascade membrane methanol reactor (CMMR) in the presence of long term catalyst deactivation was developed. In the first catalyst bed the synthesis gas partially convert to methanol. In the second reactor the reaction heat is used to preheat the feed gas to the first bed. The wall of the tubes in the both of reactors is covered with a palladium–silver membrane. The simulation results represent 4.7% and 3.92% enhancement in the yield of methanol production during 1400 days of operation in the CMMR in comparison with conventional dual type methanol reactor (CDMR) and membrane dual type methanol reactor (MDMR), respectively and a favorable profile of temperature and activity along the CMMR relative to MDMR and CDMR. Copyright © 2010 John Wiley & Sons, Ltd.     

生物质液化制备合成气的研究

采用热化学方法有两个技术途径可以将生物制备成合成气：一是直接气化；二是先液化后气化。文章分析了对比这两种途径的优缺点，并简要阐述了先液化后气化制备合成气技术的研究现状和未来展望。