Characteristic of macroporous CeO2-ZrO2 oxygen carrier for chemical-looping steam methane reforming

Chemical-looping steam methane reforming （CL-SMR） is a novel process towards the production of pure hydrogen and syngas, consisting ofa syngas production reaction and a hydrogen production reaction. Macroporous CeQ-ZrO2 oxygen carders with different pore sizes prepared by colloidal crystal templating method and characterized by techniques of scalming electron microscopy （SEM）, transmission electron microscopy （TEM）, Brunauer-Emmett-Teller （BET）, X-ray diffraction （XRD） and temperature pro- grammed reduction （H2-TPR） were tested in CL-SMR process. For comparison, nonporous CeO2-ZrO2 oxygen carrier prepared by precipitation method was also investigated. It was found that macroporous CeO2-ZrO2 oxygen carriers owned higher reducibility and reactivity in CL-SMR process than nonporous samples. For the macroporous CeO2-ZrO2 sample, the decline of pore size could im- prove the reducibility and reactivity. The macroporous sample with a pore size of 100 nm （labeled as Ce-Zr-100） showed the highest performance for the co-production of syngas and hydrogen during the successive CL-SMR redox cycles. After 10 redox cycles, it still retained good porous structure and reducibility. It was found that the porous structure could accelerate the oxygen release from bulk to surface, leading to a good mobility of oxygen and higher reducibility. In addition, it was also favorable for diffusion and penetration of methane and water steam into the sample particles to accelerate the reaction rate.     

甲烷部分氧化LSF中空纤维透氧陶瓷膜反应器性能研究

以自合成的La0.7Sr0.3FeO3-δ(LSF)钙钛矿陶瓷粉体为原料,采用相转化烧结技术制备了致密的LSF中空纤维陶瓷膜。在纤维膜与外套管间填充镍基催化剂组装成甲烷部分氧化制备合成气膜反应器。考察了陶瓷膜反应器用于甲烷部分氧化制备合成气的性能。     

Hydrocracking of Gudao Residual Oil with Dispersed Catalysts Using Supercritical Water-Syngas as a Hydrogen Source. Part II: The Comparison of Residue Hydrocracking in Different Hydrogen Sources

Abstract

Different catalytical hydrogen sources were compared with molecular hydrogen gas in the hydrocracking of Gudao residue in the presence of catalysts (PMA). The results showed that alternative hydrogen sources were effective in catalytic hydroconversion of heavy oil. The hydroconversion of residue in supercritical water-syngas system showed similar results when performed with molecular hydrogen.     

Fe负载量对Fe/γ-Al_2O_3催化剂催化合成低碳烯烃性能的影响

采用浸渍法制备了不同Fe负载量的Fe/γ-Al2O3催化剂,通过XRD、N2物理吸附-脱附、H2-TPR和H2化学吸附等手段对Fe/γ-Al2O3催化剂进行了表征,并在固定床中评价了催化剂的费托合成反应性能。在285℃、2.5 MPa、气态空速4 000 h-1、n(H2)∶n(CO)=2的条件下,随Fe负载量的增加,Fe/γ-Al2O3催化剂的CO加氢活性先增加后降低,在Fe负载量为16%(w)时活性最高;CO2选择性逐渐增加,C5+选择性逐渐降低,C2H4选择性与C2H6选择性相当,而C3H6和C4H8的选择性优于相应烷烃的选择性;在Fe负载量9%～21%(w)的范围内,Fe负载量对Fe/γ-Al2O3催化剂的低碳烯烃选择性影响不明显。     

合成气组分对甲醇合成的影响

分析合成气各组分及毒物对甲醇合成反应的影响,并探讨相应的预防及处理措施。     

煤直接制乙醇技术的应用前景分析

从当前国内外乙醇工业的发展现状出发,着重分析与论述基于煤气化的合成气直接制乙醇技术,并对其在未来发展与应用的前景进行分析和论述。     

Anaerobic CO2 fixation by the acetogenic bacterium Moorella thermoacetica

Anaerobic bacteria such as Moorella thermoacetica have the capacity of fixing carbon dioxide with carbon monoxide and hydrogen for the production of ethanol, acetic acid, and other useful chemicals. In this study, we evaluated the fixation of CO₂ for the production of acetic acid, as a product in its own right but also as precursor for lipid synthesis by oleaginous organisms. We achieved maximum cell optical density of 11.3, acetic acid titer of 31 g/L, and productivity of 0.55 g/L‐h at CO mass‐transfer rate of 83 mM/h. We also showed electron availability by CO mass transfer limited the process at CO mass transfer rates lower than 30 mM/h. Further enhancement of mass‐transfer rate removed such limitations in favor of biological kinetics as main limitation. This work underlines the potential of microbial processes for converting syngas to fuel and chemical products in processes suitable for distributed feedstock utilization. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3176–3183, 2013     

IGCC系统关键部件的选择及其对电厂整体性能的影响——(3)气化炉合成气冷却器与余热锅炉的匹配

带有合成气冷却器的气化炉,因能将高温合成气中的显热提供给余热锅炉,其系统效率高且更具有研究价值．采用GT PRO软件,研究了余热锅炉和合成气冷却器联合运行的工作过程．模拟和对比了余热锅炉在不同位置抽取和回送冷却介质对系统整体技术、经济性能造成的影响．综合分析之后,提出了几种性价比较高的流程布置．     

气流床煤气化辐射废锅内多相流动与传热

采用多相流动与传热模型耦合的数值方法,对气流床煤气化辐射废锅内多相流场与传热过程进行了数值模拟。在Euler坐标系中采用组分输运模型计算气体组分扩散过程,并通过realizable k-ε湍流模型计算炉内流场,煤渣颗粒运动轨迹在Lagrange坐标系中计算,并考虑了气固相间双向耦合。利用灰气体加权和模型与离散坐标法相结合,计算了炉内辐射传热过程,并考虑了煤渣颗粒的热辐射特性。结果表明：炉体入口存在张角约为10°的中心射流区,其流速和温度均较高,且周围存在明显回流区,回流区内部分颗粒富集;大部分颗粒直接落入渣池,且粒径越大落入渣池时温度越高;炉内温度分布除中心射流区,整体分布均匀,且随壁面灰渣厚度的增加而升高;计算结果与实验测量结果及文献值基本一致。     

Evolution of syngas from cardboard gasification

Evolutionary behavior of syngas characteristics evolved during the gasification of cardboard has been examined using a batch reactor with steam as a gasifying agent. Evolutionary behavior of syngas chemical composition, mole fractions of hydrogen, CO and CH₄, as well as H₂/CO ratio, LHV (kJ/m³), hydrogen flow rate, and percentage of combustible fuel in the syngas evolved has been examined at different steam to flow rates with fixed mass of waste cardboard. The effect of steam to carbon ratio as affect by the steam flow rate on overall syngas properties has therefore been examined. A new parameter called coefficient of energy gain (CEG) has been introduced that provides information on the energy gained from the process. This new parameter elaborates the importance of optimizing the sample residence time in the reactor.