烃类水蒸汽重整制氢研究进展

烃类水蒸汽重整是工业上大规模制氢的主要方法.综述了近十年来国内外烃类水蒸汽重整制氢技术的研究进展,重点从催化剂以及反应工艺方面进行介绍及评述,并指出烃类水蒸汽重整制氢的重点发展方向.     

甲醇蒸汽重整制氢反应动力学研究进展

甲醇蒸汽重整制氢技术对于解决汽车、船舶等交通工具上燃料电池的氢源问题具有重要意义,近年来已成为碳氢燃料重整制氢的研究热点。本文首先综述了甲醇蒸汽重整制氢的5种反应机理,该方面的研究仍处于定性和推理阶段,尚未达成统一的结论。然后分析了甲醇蒸汽重整反应动力学的研究进展,发现大多研究是基于Cu系催化剂提出,反应温度集中在160～350℃,反应压力多为1atm,研究表明反应物水醇比最优值为1.3～1.4。最后,整理了研究中所提出的动力学模型,指出相较于单速率和三速率模型,双速率模型可反映产物中CO的含量及其对反应速率的影响,且模型相对简单,动力学方程的求解过程也相对容易,但其适用性还有待进一步验证。本文可为甲醇蒸汽重整制氢系统的设计与优化提供理论依据。     

甲醇水蒸汽重整制氢反应的热力学分析

针对甲醇水蒸汽重整制氢反应体系,通过理论计算研究了化学平衡常数随温度的变化规律,指出该反应适宜的反应温度。选取自行开发的CuZnZrAlO催化剂作为研究对象,比较了反应体系中理论平衡组成和实际组成之间的差别,研究了体系中两个独立反应——甲醇分解和水蒸汽变换的反应进度受温度影响的敏感度。通过比较实际反应性能和理论平衡极限的差别,为CuZnZrAlO催化剂的进一步改进提供了研究方向。     

烃类原料蒸汽转化制氢系列催化剂及应用

为制取工业氢气、氨合成气和含有CO＋H2的各种合成气，以烃类为原料的蒸汽转化法是应用最广、效率最高的基本工业方法。基本工艺过程：烃类原料经净化，配入蒸汽，混合预热，进入500-850℃左右的变温转化催化剂床层内，发生水蒸气（和CO2）催化转化反应，生成含有H2、CO、CO2和少量CH4的粗合成气，后经变换和脱碳、甲烷化或PSA净化，分别生产高纯工业氢和不同H2／CO比的羰基合成气。一段转化工艺气再经二段转化，可生产氮氢比适宜的氨合成气。     

反应吸附强化C2/C3烃水蒸气重整制氢反应热力学计算

为拓宽反应吸附强化水蒸气重整制氢(ReSER)原料的应用范围,采用化工流程模拟软件Aspen Plus,针对包括C2H4、C2H6、C3H6、C3H8的C2/C3轻烃ReSER制氢反应可行性和优化条件进行热力学分析计算。在选择的反应压力0.1~5 MPa,温度200~800℃,水碳摩尔比(S/C)1~8和吸附剂中氧化钙和原料碳摩尔比(Ca/C)0~5条件下进行热力学分析计算。计算结果表明:在优选的水碳比(S/C)4,钙碳比(Ca/C)2.5,温度200~650℃,压力0.1~1.8 MPa的条件下,C2H4、C2H6、C3H6、C3H8均可分别通过ReSER反应获得H2含量在95%以上的产物,产物中H2浓度均随着水碳比和钙碳比的增大而提高。在假设的水碳比4,钙碳比2.5条件下,当CO2脱除率达到0.9以上,C2H4、C2H6、C3H6、C3H8的反应温度分别高于250、400、250、350℃时,产物中H2摩尔分数均可达到95%以上,产物中的H2浓度随着反应温度的升高和CO2脱除率的增加而提高。当CO2脱除率低于0.9,产物H2摩尔分数要达到95%时,C2H4、C2H6、C3H6、C3H8的反应温度均需升高50℃。在相同长度C链的烃类中,烯烃比烷烃更容易发生ReSER反应。而原料的碳链越长,则越容易发生ReSER制氢反应。     

甲醇部分氧化-蒸汽重整制氢的化学平衡计算

用热力学方法研究甲醇部分氧化－蒸汽重整耦合制氢反应。计算出反应系统在不同温度下的反应平衡常数和平衡组成,为催化剂的研制和动力学模型的建立提供依据。     

反应吸附强化C2/C3烃水蒸气重整制氢反应热力学计算

为拓宽反应吸附强化水蒸气重整制氢（ReSER）原料的应用范围,采用化工流程模拟软件Aspen Plus,针对包括C₂H₄、C₂H₆、C₃H₆、C₃H₈ 的C2/C3轻烃 ReSER制氢反应可行性和优化条件进行热力学分析计算。在选择的反应压力0.1～5 MPa,温度200～800℃,水碳摩尔比（S/C）1～8和吸附剂中氧化钙和原料碳摩尔比（Ca/C）0～5条件下进行热力学分析计算。计算结果表明：在优选的水碳比（S/C）4,钙碳比（Ca/C）2.5,温度200～650℃,压力0.1～1.8 MPa的条件下, C₂H₄、C₂H₆、C₃H₆、C₃H₈均可分别通过ReSER反应获得H₂含量在95%以上的产物,产物中H₂浓度均随着水碳比和钙碳比的增大而提高。在假设的水碳比4,钙碳比2.5条件下,当CO₂脱除率达到0.9以上,C₂H₄、C₂H₆、C₃H₆、C₃H₈的反应温度分别高于250、400、250、350℃时,产物中H₂摩尔分数均可达到95%以上,产物中的H₂浓度随着反应温度的升高和CO₂脱除率的增加而提高。当CO₂脱除率低于0.9,产物H₂摩尔分数要达到95%时,C₂H₄、C₂H₆、C₃H₆、C₃H₈的反应温度均需升高50℃。在相同长度C链的烃类中,烯烃比烷烃更容易发生ReSER反应。而原料的碳链越长,则越容易发生ReSER制氢反应。     

国内外蒸汽转化制氢催化剂及工艺进展

本文分别对烃类蒸汽转化制氢技术中涉及的原料、工艺、设备及催化剂等方面的国内外进展进行了讨论，评述了烃类蒸汽转化制氢技术的发展趋势并提出有关建议。     

轻油蒸气转化催化剂积炭研究进展

分析了轻油蒸气转化催化剂积炭原因和积炭机理;介绍了国内外对各种抗积炭性单金属和双金属催化剂的研究进展;评述了催化剂制备工艺、栽体和助剂抗积炭的研究进展。     

Thermally Coupled Catalytic Reactor for Steam Reforming of Methane and Liquid Hydrocarbons: Experiment and Mathematical Modeling

An energy-efficient catalytic reactor for producing synthesis gas from methane and liquid hydrocarbons is proposed that is based on the coupling of an endothermic reaction (steam reforming of methane, hexane, or isooctane) and an exothermic reaction (hydrogen oxidation by atmospheric oxygen) in a single cocurrent apparatus. To describe the processes in such an apparatus, a two-dimensional two-temperature mathematical model is developed. It was revealed experimentally and by mathematical modeling that the heat- and mass-transfer coefficients of the gas flow in contact with the catalytically active wall in the exothermic reaction zone considerably affect the thermal conditions in the reactor.     

Thermodynamics on Landfill Gas Reforming

Landfill gas is a type of methane‐rich biogas which supplies renewable resources for clean fuels production. In this paper, the characteristics and optimum conditions of simulated landfill gas and biogas reforming reactions for H₂ production are investigated. The temperature, varied from 373.15 K to 1273.15 K, and pressure, varied from 1.013 bar to 40.013 bar, applied for the reforming system are evaluated. In addition, the effect of steam concentration, traces of hydrocarbons, and the ratio of C/H/O are analyzed using thermodynamic theories. Both the calculation and analyzed results demonstrate that the reforming system is primarily comprised of endothermic reactions. It favors lower pressure and higher temperature. Traces of hydrocarbons would result in a slight increase to CO for this system. A high ratio of CO₂ would result in more production of CO in the reforming process. Preliminary experiments on fuel cells indicate this gas‐reforming simulation is an elementary theory for fuel supply.     

轻烃蒸汽转化制氢HYSYS软件全流程模拟

轻烃蒸汽转化制氢作为目前国内外比较成熟的制氢技术之一使用很广泛,通过HYSYS软件对榆林炼油厂20 000 m~3/h天然气蒸汽转化制氢进行全流程模拟,详细介绍了装置各工序流程模拟过程中模块的建立过程及方法,并结合现场实际参数对全流程模拟进行优化设置,将全流程模拟的原料适用范围扩展至炼厂副产的轻烃类混合物,使得此流程模拟计算在以轻烃蒸汽转化制氢工艺技术的设计过程中通用,并对使用轻烃蒸汽转化制氢工艺技术的生产装置在开工和生产阶段提供可靠的动态参考数据。     

蒸汽加热煅烧炉汽轴的改造

介绍纯碱生产中的大型设备蒸汽加热煅烧炉的关键部件汽轴出现的设计结构缺陷及设计改造的情况     

Thermodynamic Analysis of Glycerol Steam Reforming

A thermodynamic analysis of steam reforming of glycerol using the stoichiometric method has been performed. Since the aim of this work is to study product distribution and coke formation in equilibrium, two different models have been proposed: (a) CO as primary product and (b) CO₂ as primary product. Moreover, substantial information regarding the behavior of the different reactions could be acquired. Product distribution at equilibrium has been investigated in a broad range of conditions: temperature (600–1200 K), water‐to‐glycerol feed molar ratio (0:1–10:1), and pressure (1–9 atm). Glycerol conversion results completely over the whole range of the mentioned conditions. Consequently, product distribution at equilibrium is determined by water gas shift (WGS) and methanation or methane steam reforming reactions. Finally, high temperatures and a high water‐to‐glycerol feed molar ratio favor hydrogen production and decrease both methane and coke.     

Carbon Deposition in Steam Reforming and Methanation

Deactivation of supported metal catalysts by carbon or coke formation is a problem of serious magnitude in steam reforming, methanation, and other important catalytic processes. Its causes are generally threefold: (1) fouling of the metal surface, (2) blockage of catalysts pores and voids, and/or (3) actual physical disintegration of the catalyst support. Since loss of catalytic activity and physical destruction of the catalyst by carbon deposits can occur rapidly (within hours or days) under unfavorable conditions, understanding and control of these effects are of major technological and economical importance.     

Combined Steam Reforming of Methane and Fischer–Tropsch Synthesis for the Formation of Hydrocarbons: A Proof of Concept Study

Higher alcohol synthesis over a K₂O-promoted Co₂O₃/CuO/ZnO/Al₂O₃ catalyst has been studied in an internal recycle reactor under steady-state conditions using hydrogen to carbon monoxide inlet ratios between 0.5 and 3.3 and inlet carbon dioxide concentrations between 0 and 10%. The selectivity of hydrocarbons and alcohols with 1-8 carbon atoms was obtained as a function of exit carbon dioxide content, exit hydrogen to carbon monoxide ratio, and operating temperature (498-578 K), using space velocities between 1500 and 15 000 h^-1 (STP). These experiments, combined with information obtained from active catalyst characterization using XPS, indicated that the chain growth probability factor of higher alcohols was independent of conversion, whereas that of hydrocarbons was dependent on conversion.     

甲醇水蒸气重整制氢催化剂性能的研究

研究共沉淀法制备Cu/Al2O3甲醇水蒸气重整制氢催化剂，考察催化剂组成和焙烧温度对催化剂性能的影响。结果表明当Cu质量分数为30．9％，焙烧温度为500℃时，催化剂性能最佳。并采用X射线衍射（XRD），程序升温还原（TPR）和热重分析等方法对催化剂表面性质进行探讨。