Rh/MgO/γ-Al2O3上的毫秒级甲烷蒸汽重整过程

采用负载型Rh/MgO/γ-Al₂O₃催化剂研究了毫秒级甲烷蒸汽重整过程,在水碳比为1和3的条件下,详细考察了反应温度、空速和催化剂Rh含量对反应转化率和选择性的影响。研究结果表明,Rh/MgO/γ-Al₂O₃催化剂在毫秒级操作条件下具有良好的催化性能,使用5%（质量分数）Rh催化剂,在水碳比3、反应温度1150 K、空速641.11 L•（g cat）^-1•h^-1时,CH₄转化率约90%,CO₂选择性约20%,毫秒级接触时间反应行为即可接近热力学平衡。高温有利于毫秒级甲烷蒸汽重整过程。     

Milliseconds steam reforming of methane using Rh/MgO/γ-Al2O3 catalyst

采用负载型Rh/MgO/γ-Al₂O₃催化剂研究了毫秒级甲烷蒸汽重整过程,在水碳比为1和3的条件下,详细考察了反应温度、空速和催化剂Rh含量对反应转化率和选择性的影响。研究结果表明,Rh/MgO/γ-Al₂O₃催化剂在毫秒级操作条件下具有良好的催化性能,使用5%（质量分数）Rh催化剂,在水碳比3、反应温度1150 K、空速641.11 L•（g cat）^-1•h^-1时,CH₄转化率约90%,CO₂选择性约20%,毫秒级接触时间反应行为即可接近热力学平衡。高温有利于毫秒级甲烷蒸汽重整过程。     

工艺条件对氯化氢催化氧化反应的影响

采用类似Deacon过程的氯化氢催化氧化法制备氯气，选用自制的氯化铜为活性组分的铜基催化剂，通过正交实验考察反应温度、氯化氢与氧气体积比和空速对氯气产率的影响。结果表明，反应温度升高，氯化氢转化率增大；原料氯化氢与氧气体积比减小以及氧气投料量增加，氯化氢转化率明显升高；空速为（0.11~0.15） h^-1时，氯化氢转化率变化不大，空速为0.20 h^-1时，氯化氢转化率明显降低。在反应温度420 ℃、氯化氢与氧气体积比2∶1和空速0.15 h^-1条件下，氯化氢转化率最高，达到76.98%～80.58%。     

直流电弧等离子体甲烷二氧化碳重整反应

采用一种简单结构的直流电弧反应器,在无催化剂存在的条件下,高效率地实现了毫秒级甲烷二氧化碳的重整反应,产物选择性好,并且在反应过程中几乎没有积炭生成。在恒定输入功率(170W)的条件下考察了气体总流量和二氧化碳/甲烷摩尔比对反应结果的影响。提高反应气体的输入能量密度可以提高甲烷和二氧化碳的转化率,并且能够有效地抑制副产物的生成。当二氧化碳/甲烷摩尔比为1时,二氧化碳转化率为89.8%,甲烷转化率为96.3%,氢气和一氧化碳的选择性分别为99.6%和99.3%。二氧化碳过量可显著促进甲烷的转化以及同时获得合成气的高选择性。采用比能耗对该过程的能量利用效率进行了分析,以期指导反应条件优化以提高过程的能量利用效率。     

新型非常规天然气直接催化转化制芳烃催化剂的研究

近年来,常规天然气供应紧张,因此非常规天然气的开发利用显得尤为重要。甲烷无氧芳构化作为非常规天然气的直接转化方式之一,由于其工艺流程简单、芳烃选择性集中、产物附加值高等特点,一直受到广大科研工作者的关注。为提高甲烷转化率及甲苯和二甲苯等产物的选择性,通过一步浸渍法制备了0.189%Mg/8%Mo/HZSM-5（以质量分数计）催化剂,在700 ℃、101 kPa条件下通过将甲烷无氧芳构化反应与芳烃烷基化反应耦合,其中甲醇作为烷基化试剂与甲烷以共进料的方式进入反应体系,将甲烷的转化率提升至27.45%、甲苯和二甲苯的选择性分别达到28.29%和24.65%,并且8 h内催化剂未出现活性减弱,实现了反应的高效稳定运行。     

Rh/MgO/γ-Al2O3上的毫秒级甲烷蒸汽重整过程

采用负载型Rh/MgO/γ-Al2O3催化剂研究了毫秒级甲烷蒸汽重整过程,在水碳比为1和3的条件下,详细考察了反应温度、空速和催化剂Rh含量对反应转化率和选择性的影响。研究结果表明,Rh/MgO/γ-Al2O3催化剂在毫秒级操作条件下具有良好的催化性能,使用5%(质量分数)Rh催化剂,在水碳比3、反应温度1150K、空速641.11 L·(gcat)-1·h-1时,CH4转化率约90%,CO2选择性约20%,毫秒级接触时间反应行为即可接近热力学平衡。高温有利于毫秒级甲烷蒸汽重整过程。     

Ni-Rh/Al2O3催化剂上甲烷-氘化氢间的氢氘交换性能

采用Ni-Rh/Al₂O₃催化剂,在固定床微型反应器上考察了Ni-Rh/Al₂O₃催化剂对甲烷的氢氘交换的催化性能。结果表明,在进料组成不变的条件下,当温度低于692K时,甲烷的转化率随温度的升高而快速升高,当温度高于692K时,甲烷的转化率不随温度的升高而变化;当温度低于692K时,甲烷的转化率随反应物流量的增加而明显减小,当温度高于692K时,甲烷的转化率基本不随温度和反应物流量的变化而变化;在反应物总流量不变的条件下,当HD/CH₄流量比为1.1～2.5时,甲烷的转化率随着HD/CH₄流量比增加而减小。     

环丁砜处理磺酸树脂高效催化聚甲氧基二甲醚合成

聚甲氧基二甲醚（DMM_3～7）作为柴油添加剂可提高柴油十六烷值和燃料利用率,具有广阔应用前景。以环丁砜处理后的磺酸树脂为催化剂,用于甲缩醛（DMM）和三聚甲醛（TOX）合成DMM_3~7反应,系统地研究了不同条件因素对反应过程中原料转化率和产物选择性的影响,并推断了反应机理。发现：反应体系中含有不同微量（mg/kg级）H₂O对原料转化率和产物选择性影响较大;当H₂O含量超过一定值时,有白色沉淀多聚甲醛（PF）生成,PF选择性随H₂O含量增加而增大,同时生成大量甲醇,导致目标产物DMM_3~7选择性降低。创新地采用环丁砜对酸性磺酸树脂NKC-9进行脱水处理,使固体催化剂表面及孔道吸附H₂O含量从2154 mg/kg显著降至198 mg/kg;同时使用13X分子筛对原料DMM进行吸附脱水处理,使DMM中H₂O含量从710 mg/kg明显降至54 mg/kg。当反应温度313 K（40℃）、反应2 h、压力1.0 MPa、DMM与TOX质量比2/1时,DMM和TOX转化率以及DMM_3～7质量选择性分别从48.27%、88.41%以及45.27%显著提升至52.91%、93.34%和61.58%。与文献报道的数据相比,改性后的磺酸树脂在低温下即表现出极佳的催化效果,DMM_3～7质量选择性突破60%。     

1,2-丙二醇选择性氧化制备丙酮醛催化剂研究

采用银改性和银负载制备了两种1,2-丙二醇空气氧化合成丙酮醛催化剂,并对其性能进行了研究。在固定催化剂浓度及溶剂比条件下,对催化剂进行了评价。结果表明,催化剂最佳制备条件为:改性金属的盐酸溶液、一定粒度的银在50 ℃反应2 h,滴加甲醛溶液,Na₂CO₃溶液调节pH＝10,升温还原2 h,溶液进行过滤,滤饼用蒸馏水洗涤至中性,在空气条件下110 ℃干燥,分级过筛。使用该催化剂在反应温度为410 ℃、1,2-丙二醇空速12 h^－1、氧气与1,2-丙二醇物质的量比和水与1,2-丙二醇质量比分别为1.6和1的条件下,催化氧化转化率可达98.4%,催化剂选择性可达82.2%,催化剂寿命可达90天。     

丁酮合成丁酮肟的研究

在常压条件下,对以钛硅分子筛TS-1为催化剂催化丁酮氨氧化反应制取丁酮肟的过程进行研究。考察了TS-1催化剂的用量、酮氨物质的量比、双氧水用量、反应温度、反应时间对反应过程中丁酮的转化率和丁酮肟选择性的影响。实验结果表明,常压条件下最佳工艺条件为:过氧化氢与氨水采用连续进料的方式,TS-1催化剂的用量为10.0 g/mol,进料物质的量比为氨水∶丁酮∶双氧水=3∶1∶1.5,反应时间为3 h,反应温度为70℃。此时,丁酮的转化率为82.38%,丁酮肟的选择性为98.18%。     

生物质合成气甲烷化与变换反应串联偶合新工艺

以模拟生物质合成气为原料,在固定床反应器中,对合成气甲烷化反应工艺条件进行优化,并在此反应中串联偶合水煤气变换反应,以此提高生物质合成气中碳氢的比例,从而弥补生物质合成气碳氢比较低的不足,使生物质合成气甲烷化反应更彻底,进而提高甲烷的收率。实验结果表明,在水煤气变换空速为15 000 h~(-1)、进水量0.02 m L·min~(-1)和还原温度为450℃条件下,甲烷化催化剂的性能最优,CO转化率100%,甲烷选择性对于整个偶合反应为50%,但就单一甲烷化反应高达99%。     

微通道反应器内氢气催化燃烧

在微尺度化学反应器内对氢气/空气催化燃烧反应进行了研究,考察了操作条件对反应行为的影响,并建立相应的数学模型,同时也对该类反应器应用于强放热反应过程的动力学研究进行初步的探讨.实验过程中H2入口浓度为3% (mol)～15%（mol）,结果表明微通道反应器可使处于爆炸极限内的氢氧催化燃烧反应在高空速、低压降、等温及动力学控制区内安全地进行.在H₂入口浓度8%（mol）、反应温度150 ℃、空速1.0×10⁶ h^-1条件下,转化率高达90%.     

流化床中甲烷催化裂解制备碳纳米管和氢气

利用高活性的纳米Ni/Cu/Al₂O₃催化剂,在流化床反应器中研究了CH₄裂解制备碳纳米管与H₂的过程.CH₄的转化率受流化床中的操作条件（温度、空速、气速及升温速率等）影响,碳纳米管的形貌也受过程的升温速率影响.在低升温速率下,能够同时得到较高的CH₄转化率与形貌较好的碳纳米管.而且采用低的升温速率,可以在流化床（提供碳纳米管生长的自由空间）中连续生长碳纳米管,从而为将来的连续化大批量制备碳纳米管奠定了基础.     

Kinetic parameter estimation of the Fischer-Tropsch synthesis reaction on K/Fe-Cu-Al catalysts

This paper addresses the development of a mathematical model for a fixed-bed reactor where the Fischer-Tropsch synthesis reaction takes place. The model includes the consumption rate of carbon monoxide and the production rates for paraffin and olefin chains (up to the length of 47). The kinetic parameters are estimated using the experimental data under various experimental conditions with the effect of temperature, space velocity, the composition of feed mixture and pressure included. The simulation results with the estimated parameters predict the CO conversion, methane selectivity, paraffin selectivity and the entire distribution of hydrocarbon products satisfactorily. A further investigation on the effect of operating conditions shows that the ratio of hydrogen to carbon monoxide and the pressure are the effective variables for the determination of the entire distribution.     

A new process for synthesis gas by co-gasifying coal and natural gas

Production of synthesis gas with coal and natural gas co-gasification is a new process based on coupling of methane steam-reforming and coal gasification. The process concept is discussed in this paper. Experiments are carried out in a laboratory fixed-bed gasifying reactor to investigate the effect of feedstock on composition, ratio of hydrogen to carbon monoxide, concentrations of hydrogen and carbon monoxide in the produced raw synthesis gas. Preliminary experimental results indicate that the effect of steam flow rate on component, ratio of hydrogen to carbon monoxide and concentrations of hydrogen and carbon monoxide of the raw synthesis gas is slight, while the effect of oxygen flow rate is pronounced. When the ratio of oxygen to methane in feedstock is below 1, the ratio of hydrogen to carbon monoxide is greater than 1 and the total concentration of hydrogen and carbon monoxide is above 90%. Comparison of experimental results with calculated results shows that the composition of raw synthesis gas is near equilibrium.     

Oxidative methane conversion to carbon monoxide and hydrogen at low reactor wall temperatures over ruthenium supported on silica

Oxidative methane conversion to carbon monoxide and hydrogen is catalyzed over ruthenium supported on silica at reactor wall temperatures as low as 400° C when the flow rate of reactants (methane and oxygen) is significantly high. The conversion of methane and the yields of carbon monoxide and hydrogen increase with increase in the flow rate of the reactants while oxygen is always completely consumed. Addition of carbon dioxide to the reactant flow can increase the yield of carbon monoxide in the reaction, suggesting that carbon dioxide functions as an oxidant and the actual surface temperature of the catalyst is sufficiently high that thermal conversion of methane via carbon dioxide and water can take place.     

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.     

Direct conversion of methane to acetylene or syngas at room temperature using non-equilibrium pulsed discharge

Non-catalytic direct conversion of methane to valuable products was studied using non-equilibrium pulsed discharge under the conditions of ambient temperature and atmospheric pressure. Acetylene was produced with 95% selectivity and 52% methane conversion. An addition of oxygen, carbon dioxide and steam contributed significantly to suppress the carbon deposition and produced carbon monoxide as well as acetylene. Methane conversion increased with an increase in the pulse frequency while the product selectivity remained almost constant. The selectivity depended on the composition of the feed gas. The effect of the partial pressure of oxygen was examined, and it was found that the pulsed discharge would be able to produce synthesis gas by partial oxidation of methane. Carbon monoxide selectivity of 79% with methane conversion of 76% was obtained under the conditions of CH₄/O₂=25/25 cm³ min⁻¹, gap distance of 10 mm and the frequency of 45 Hz.