甲醇合成铜基催化剂硫化氢中毒研究(Ⅰ)——硫化氢中毒本征失活动力学

研究了甲醇合成C207铜基催化剂硫化氢中毒本征失活动力学.研究表明,硫化氢分压增加,失活速率加快;温度升高,失活速率加快.本征失活速率方程为r_d=-da/dr=0.1474×10~(12)exp(-81128/R_gT)P_(H_2s~a)     

甲醇合成铜基催化剂硫化氢中毒研究(Ⅱ)——表面中毒催化剂效率因子

在常压下内循环无梯度反应器中测定了工业颗粒C207铜基化剂在入口硫化氢含量7.19×10~(-4)通硫化氢4、8、12h后甲醇分解反应宏观速率,测定了催化剂孔径分布和曲折因子.由俄歇电子能谱测定获得,通H_2S 4h未中毒比半径x_c为0.938,通H_2S 8h为0.916,通H_2S 12h为0.896,与由本征失活动力学获得的计算值相符合.探讨了计算表面中毒催化剂效率因子的甲醇单组分模型和多组分模型的正交配置解,解决了颗粒催化剂存在表面中毒和中心平衡死区的效率因子的求解问题,中毒催化剂效率因子的实验值与模型计算值的相对误差,其绝对值的平均值在11%以内,表明表面中毒催化剂效率因子的计算模型是可行的.     

甲醇合成铜基催化剂硫化氢中毒研究(Ⅱ)——表面中毒催化剂效率因子

在常压下内循环无梯度反应器中测定了工业颗粒C207铜基化剂在入口硫化氢含量7.19×10~(-4)通硫化氢4、8、12h后甲醇分解反应宏观速率,测定了催化剂孔径分布和曲折因子.由俄歇电子能谱测定获得,通H_2S 4h未中毒比半径x_c为0.938,通H_2S 8h为0.916,通H_2S 12h为0.896,与由本征失活动力学获得的计算值相符合.探讨了计算表面中毒催化剂效率因子的甲醇单组分模型和多组分模型的正交配置解,解决了颗粒催化剂存在表面中毒和中心平衡死区的效率因子的求解问题,中毒催化剂效率因子的实验值与模型计算值的相对误差,其绝对值的平均值在11%以内,表明表面中毒催化剂效率因子的计算模型是可行的.     

废水催化湿式氧化中CuO催化剂的稳定性研究

以苯酚配水溶液为研究对象,考察负载型CuO催化剂在微型滴流床反应器中连续流工况下的稳定性。结果表明,温度和进水pH值是影响催化剂稳定性的主要因素,高温下催化剂失活速率加快;负载型CuO/γ-Al2O3催化剂在中性进水(pH0=7.00)条件下具有可观的催化活性且可保持连续使用20hr不失活;而在酸性进水(pH0=5.90)条件下,尽管其催化活性较高但失活现象严重。     

紫外光分解硫化氢制氢的研究

以10W低压汞灯（特征谱线波长,λ=253.7nm,简称UVC）作为光源,硫化钠的水溶液作为反应介质,进行了UVC直接分解硫化氢制氢反应（简称UVC-H2S-H2）的研究.考察了反应介质中硫的存在形式、硫化钠的浓度、反应介质pH值以及连续通入硫化氢的流量等反应条件对UVC-H2S-H2的影响.实验结果表明,UVC可以在无催化剂条件下直接分解硫化氢制氢.当以0.6mol/L硫化钠水溶液为反应介质,以25mL/h流量连续向反应介质中通入硫化氢时,UVC-H2S-H2产氢速率可达3.0mL/W.h.     

锆基双金属氧化物催化剂硫中毒的研究

在工业二氧化碳加氢制甲醇过程中,硫化氢气体的引入将对该过程中使用的催化剂活性及稳定性带来负面的影响。基于此,采用微反应合成法成功制备了InZrO_x和ZnZrO_x锆基催化剂,并研究了在二氧化碳加氢反应中,硫化氢气体对锆基催化剂的结构性质及其催化性能的影响规律。结果表明,在T=573 K、p=3.0 MPa和GHSV=18 000 mL/(g_cat·h)条件下,仅通入二氧化碳/氢气反应气时,InZrO_x和ZnZrO_x催化剂的二氧化碳转化率和甲醇选择性分别为7.2%、9.3%和93%、92%。在二氧化碳/氢气原料气中通入体积分数为5×10^-3硫化氢气体时,InZrO_x和ZnZrO_x催化剂的二氧化碳转化率和甲醇选择性都降为0,这主要是因为硫化氢气体占据了氧空位,导致锆基双金属氧化物催化剂硫中毒失活。当停止通硫化氢气体时,InZrO_x和ZnZrO_x催化剂的二氧化碳转化率和甲醇选择...     

硫化氢对几种管线钢腐蚀试验研究

通过硫化氢腐蚀模拟试验研究了三种管线钢(X60、X65、X70)在不同浓度硫化氢环境下的腐蚀情况。实验表明,硫化氢浓度对三种管线钢腐蚀速率影响趋势相同且在高含硫化氢环境中腐蚀速率并不高,腐蚀速率受pH影响,pH值越小腐蚀速率越大。     

基于质谱技术的大鼠硫化氢中毒血浆蛋白质组学研究

硫化氢中毒机理尚未在蛋白质层面阐明,寻找血液中的蛋白质标识物在临床及法医学上具有重要意义。近年发展起来的液相色谱-质谱技术的定量蛋白质组学(iTRAQ/TMT)技术为筛选生物标识物提供了新的有力工具。采用蛋白质组学方法研究了硫化氢中毒的大鼠模型的结果。大鼠暴露于150mg/m~3浓度受控的硫化氢环境中,时间分别为0、2和4h。收集大鼠血液后,分离血浆并用蛋白质浓缩试剂盒(ProteoMiner)去除高丰度蛋白质,并通过串联质谱标签标记技术和纳流液相色谱-串联质谱(Nano HPLC MS/MS)进行定量蛋白分析。实验采取两组平行重复以确认鉴定及定量结果。在2次重复实验中,共有520个蛋白被鉴定并进行后续生物信息学分析。结果表明:蛋白质组学技术是在蛋白质水平上研究并揭示硫化氢中毒的机理。     

硫化氢对铁铬钼催化剂一氧化碳变换动力学行为的影响

在玻璃反应器中,以混有不同浓度(0、450、850ppm)硫化氢的工业半水煤气研究了B112型铁铬钼变换催化剂的动力学行为,接二级反应速率方程对试验数据进行处理,其反应速率常数分别为: H_2S=0时:k_T=3.797×10~5exp(-66573/R_gT); H_2S=450ppm时:k_T=2.116×10~4exp(-57923/R_gT); H_2S=850ppm时:k_T=1.637×10~4exp(-58731/R_gT);     

提高脱硫液中硫化氢测定结果重复性

活测定脱硫液中溶解硫化氢含量采用方法Q/SY LS 1503-2009《脱硫液中溶解硫化氢含量的测定(碘量法)》。碘量法的原理是根据脱硫剂吸收硫化氢后会生成相应的盐类,在弱酸性介质中,硫(S2-)被碘(I2)氧化;而过剩的碘用硫代硫酸钠滴定。其反应式如下:S~(2-)+2I_2(过量)→S+2I~-+I_2(剩余)I_2+2Na_2S_2O_3→NaI+Na_2S_4O_6,分析方法Q/SY LS 1503-2009《脱硫液中溶解硫化氢含量的测定(碘量法)》中要求:当硫化氢含量3000mg/L时,同一样品重复测定两个结果之差应≦500mg/L。但在实际分析工程中,经常无法满足这一要求。因此本文进行了研究分析。     

Alkylation of toluene with methanol over heteropoly acid/Y-zeolite catalysts

Alkylation of toluene with methanol has been studied in a fixed bed reactor with a continuous flow system. As a promoter, heteropoly acids and their metal salts were impregnated on Y-zeolite. Catalyst impregnated with lower amount of heteropoly acid showed higher initial activity, and the catalytic activity was enhanced by more electronegative metal ion of heteropoly acid salt impregnated on Y-zeolite, Catalyst calcined at lower temperature showed higher initial activity, but its deactivation rate was faster than that calcined at higher temperature. Catalyst impregnated with BiPMo₁₂O₄₀ showed a good activity and a good regeneration ability of catalytic activity.     

Incorporation of Flexibility in the Design of a Methanol Synthesis Loop in the Presence of Catalyst Deactivation

This paper presents the incorporation of process flexibility into a methanol synthesis loop operating under catalyst deactivation. A design methodology is discussed with regard to catalyst deactivation, and some limitations are identified. In the current flexibility study the size of the reactor and recycle ratio have been fixed. Attempts to maintain methanol production at the rates observed with fresh catalyst included increased pressure, increased make up gas flow rate, and the injection of carbon dioxide into the make up gas at optimized inlet temperature. In order to provide flexibility and produce a design compatible with increased production rates, the effect of interrelating equipment had to be considered. As a result of catalyst deactivation, an increased flow rate is necessary and the altered process streams entering the preheater disturb the reactor inlet temperature. These issues should be considered in the design stage and may be resolved by the flexible designs presented.     

超临界条件下甲基萘与甲醇烷基化反应

引　言2 ,6 二甲基萘 (2 ,6 DMN)是生产新型高性能聚酯材料聚萘二甲酸乙二醇酯 (PEN)的重要原料 .目前已工业化的邻二甲苯与丁二烯烷基化生产2 ,6 DMN路线生产步骤多 ,工艺过程复杂 ,生产成本高 ,制约了PEN的发展[1,2 ] .HZSM 5沸石是一种具有强酸性、高硅铝比和独特孔道结构的分子筛 ,对许多正碳离子反应有良好的择形催化性能[3] .HZSM 5催化甲基萘 (DMN)与甲醇烷基化合成 2 ,6 DMN路线工艺过程简单 ,产品选择性高 ,是一条具有发展前景的技术路线[4 ] .然而 ,在常压下进行烷基化反应时 ,反应活性低 ,催化剂容易因结焦而失去原有的活性[5～ 7] .超临界流体具有良好的溶解和扩散性能 .在超临界条件下进行的化学反应不仅可以提高催化剂的反应活性 ,而且还可以原位维持非均相催化剂的活性 ,延长催化剂的寿命[8,9] .本文正是基于超临界流体独特的性质 ,探索在超临界条件下甲基萘与甲醇烷基化反应中提高反应活性和延长催化剂寿命的可能性 .1　实验部分1 1　催化剂的制备NaZSM 5沸石 (硅铝比为 38)由南开大学催化剂厂提供 .在 80℃下用 1mol...     

Spectroscopic and Kinetic Analysis of a New Low-Temperature Methanol Synthesis Reaction

The spectroscopy and kinetics of a new low-temperature methanol synthesis method were studied by using in situ DRIFTS on Cu/ZnO catalysts from syngas (CO/CO₂/H₂) using alcohol promoters. The adsorbed formate species easily reacted with ethanol or 2-propanol at 443 K and atmospheric pressure, and the reaction rate with 2-propanol was faster than that with ethanol. Alkyl formate was easily reduced to form methanol at 443 K and 1.0 MPa, and the hydrogenation rate of 2-propyl formate was found to be faster than that of ethyl formate. 2-Propanol used as promoter exhibited a higher activity than ethanol in the reaction of the low-temperature methanol synthesis.     

基于Aspen Plus用户模型的甲醇合成模拟及分析

对板间换热式甲醇合成塔建立了一维拟均相数学模型,并用四阶Runge-Kutta法求解其轴向温度与浓度分布。利用Aspen Plus中的User 2模块将其嵌入整个甲醇合成全流程进行模拟,并用取自工厂的实际数据进行验证,结果吻合良好。分析得到了原料气入口温度、操作压力、汽包压力及进料流量对反应器出口甲醇物质的量分数的影响,以及不同时期催化剂的活性分布及粗甲醇的产量分布,提出了在催化剂中后期应采取提高操作压力的措施来保证粗甲醇的产量。     

Hydrodechlorination of tetrachloroethene over Pd/Al2O3: influence of process conditions on catalyst performance and stability

The influence of process parameters (temperature, pressure, hydrogen flow rate, and nature of solvent) on both activity and stability of a 0.5% Pd on alumina catalyst used for tetrachloroethene (TTCE) hydrodechlorination in an organic matrix was studied. In the range of temperature studied (250–350 °C), higher temperatures lead to higher initial activity but faster deactivation. Increasing hydrogen flow rates, up to 0.8 L/min (STP), produce higher activity and stability of the catalyst, whereas pressure in the range 0.5–2 MPa has no significant effect. In all the cases, both hydrodechlorination and hydrogenation of the double bond take place, yielding ethane as the main product. Concerning to the solvent, there is no difference in the initial catalytic activity for either toluene or n-decane, but n-decane leads to faster catalyst deactivation.The effect of temperature and space time in TTCE conversion at the period of constant catalytic activity can be modelled by a kinetic model assuming first order for TTCE and zero-order for H₂.Finally, the performance of the Pd alumina-supported catalyst is compared with that of a Pd carbon-supported catalyst with the same metal load, used in previous works. Although the carbon-supported catalyst yields higher initial conversion, the alumina-supported catalyst is more resistant to deactivation.     

Membrane/sorption-enhanced methanol synthesis process: Dynamic simulation and optimization

In this study, a dynamic mathematical model of a Membrane-Gas-Flowing Solids-Fixed Bed Reactor (Membrane-GFSFBR) with in-situ water adsorption in the presence of catalyst deactivation is proposed for methanol synthesis. The novel reactor consists of water adsorbent and hydrogen-permselective Pd-Ag membrane. In this configuration feed gas and flowing adsorbents are both fed into the outer tube of the reactor. Contact of gas and fine solids particles inside packed bed results in selective adsorption of water from methanol synthesis which leads to higher methanol production rate. Afterwards, the high pressure product is recycled to the inner tube of the reactor and hydrogen permeates to the outer tube which shifts the reaction towards more methanol production. Dynamic simulation result reveals that simultaneous application of water adsorbent and hydrogen permeation in methanol synthesis process contributes to a significant enhancement in methanol production. The notable advantage of Membrane-GFSFBR is the continuous adsorbent regeneration during the process. Moreover, a theoretical investigation has been performed to evaluate the optimal operating conditions and to maximize the methanol production in Membrane-GFSFBR using differential evolution (DE) algorithm as a robust method. The obtained optimization result shows there are optimum values of inlet temperatures of gas phase, flowing solids phase, and shell side under which the highest methanol production can be achieved.     

甲醇制丙烯反应中ZSM-5分子筛催化剂积炭失活介尺度机制研究

甲醇制丙烯（MTP）是当前煤化工领域亟需发展的关键催化技术,积炭被认为是导致催化剂失活的重要原因之一。以积炭分子筛为研究对象,通过IGA、FTIR及TG等多种表征手段,考察甲醇的吸附行为、分子筛表面酸性、积炭成分与MTP反应中甲醇反应活性之间的构效关系。研究结果表明,甲醇的吸附量随催化剂的失活而降低,其下降速率与甲醇转化率成正比。催化剂上滞留的碳物种的主要成分为轻烃、BTX芳烃、活性结焦和积炭,而其中积炭是引起分子筛失活的主要原因。完全失活的催化剂与新鲜催化剂相比仍保留一定的甲醇吸附能力,推测积炭主要存在于酸活性中心周围。积炭首先覆盖的是B酸中心的羟基和桥式羟基,随后是非骨架Al—OH;而催化剂的甲醇转化率与分子筛中可接触的B酸和L酸数量成正比。另外,基于催化剂的失活速率与转化率存在的正比关系,结合反应动力学,推导出了失活曲线的数学表达式,理论上解释了MTP反应过程中的积炭失活介尺度机制。     

Selective kinetic deactivation model for methanol synthesis from simultaneous reaction of CO2 and CO with H2 on a commercial copper/zinc oxide catalyst

A kinetic model for the deactivation of copper/zinc oxide catalyst during the methanol synthesis has been developed. This model is of the Langmuir-Hinshelwood-Hougen-Watson type and considers two types of active sites for the deactivation of catalyst. One of the site types on copper is allocated for the deactivation of the catalyst due to carbon dioxide while another type is assigned for the deactivation of the catalyst due to carbon monoxide. The parameters of the deactivation rate equations based on the above concept have been determined using the experimental data of Hoffmann (1993). The validity of the deactivation model has been checked by comparing the results predicted by the model with experimental data different than of those used to evaluate the parameters of the model. The good agreement that noticed in this comparison confirmed the idea that CO and CO₂ are responsible at different extent for the deactivation of Cu/ZnO catalyst during methanol synthesis.