共查询到19条相似文献,搜索用时 46 毫秒
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以HZSM-5沸石分子筛为催化剂,应用常压液固相酯化反应合成了乙酸异戊酯。考察了催化剂用量,醇酸比,反应温度和反应时间对酯产率的影响,结果表明,HZSM-5用量为2克,异戊醇/乙酸为1/2.5(mol比)反应温度为130~140℃,反应时间为3小时,酯产率84%。 相似文献
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煤矸石合成纳米4A沸石分子筛的工艺研究 总被引:1,自引:0,他引:1
根据所选用煤矸石的成分特点提出了利用煤矸石合成纳米4A沸石分子筛的碱溶提取法,研究了该工艺,并通过试验优化了该工艺的技术参数,即用碳酸钠与煤矸石混合灼烧活化,以4mol/L的NaOH溶液提取硅铝酸钠,晶化温度为90℃,晶化时间为1h,合成并表征了质量性能优良的纳米4A沸石分子筛。 相似文献
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分子筛催化合成乙苯工艺与技术述评 总被引:2,自引:0,他引:2
综述了惭苯生产技术的进展,比较了分子筛催化合成乙苯几种生成工艺的优缺点以及研究现状与发展趋势,指出抑制催化剂结焦和二甲苯的生成是改进了乙苯工艺和开发新一代催化剂的关键。 相似文献
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沸石分子筛的合成与应用 总被引:8,自引:2,他引:8
沸石具有优异的物理化学性能,作为分子筛其用途极为广泛。本文概要介绍沸石分子筛人工合成的进展,分子筛水热结晶的模板机理,以及其在洗涤剂、催化剂和吸附剂/干燥剂等方面的应用现状。 相似文献
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研究了以HY分子筛为催化剂合成对乙酰氨基酚的工艺,对反应物的物质的量比、反应温度、反应时间、催化剂用量等反应条件进行了优化,实验确定最佳反应条件:对氨基苯酚与冰乙酸物质的量比为1∶10,反应温度为120℃,催化剂用量为1.5%,反应时间为5h。最佳条件下对乙酰氨基酚的收率可达92.05%,且实验证明HY分子筛催化活性具有良好的稳定性。 相似文献
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H. R. Norouzi M. A. Hasani B. Haddadi-Sisakht 《Chemical Engineering Communications》2013,200(10):1270-1293
The aim of this work is intensification of an industrial-scale production process of cumene to obtain higher profitability and reduce the energy requirements of the process. In the first step, two topological changes were made in the reactor configuration and benzene separation column, which led to a considerable reduction in utility requirements and equipment sizes in the process. In the second step, parametric optimization was carried out by a statistical method (full factorial design) to adjust the process parameters. In the final step, a pinch analysis was done to reduce utility requirements of the process. A mathematical model was developed based on the statistical analysis, which was then used to obtain optimized conditions of the process. The capital investment of the process remained almost intact, around $4.5 million, and the utility requirements reduced from $2.44 to 1.49 million/yr. These changes greatly enhanced the profitability of the process, for which the net present value was increased from $0.82 to 4.53 million. 相似文献
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The variation of the potential difference of two electrodes, connected by a voltmeter and immersed into different gel mixtures yielding various zeolites, was observed with respect to synthesis time. The potential difference-time curves obtained for zeolites such as X, A, and HS exhibited characteristic behaviors that might be helpful in their identification. These behaviors could be rationalized by taking into consideration the changes occurring mainly in the dissolved sodium and aluminum concentrations of the liquid phase, before and during the crystallization of zeolites. The relative rates of zeolite crystallization were also reflected on the potential difference-time curves. Reaction mixture compositions with relatively low Si/Al ratios generally led to sharper changes in the potential difference, due to the relatively high crystallization rates obtained in these cases. 相似文献
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Moiz Elnekave 《Chemical Engineering Communications》2013,200(6):661-673
The variation of the potential difference of two electrodes, connected by a voltmeter and immersed into different gel mixtures yielding various zeolites, was observed with respect to synthesis time. The potential difference-time curves obtained for zeolites such as X, A, and HS exhibited characteristic behaviors that might be helpful in their identification. These behaviors could be rationalized by taking into consideration the changes occurring mainly in the dissolved sodium and aluminum concentrations of the liquid phase, before and during the crystallization of zeolites. The relative rates of zeolite crystallization were also reflected on the potential difference-time curves. Reaction mixture compositions with relatively low Si/Al ratios generally led to sharper changes in the potential difference, due to the relatively high crystallization rates obtained in these cases. 相似文献
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分子筛催化下苯与长直链烯烃的烷基化反应研究 总被引:5,自引:0,他引:5
韩宾兵 《化学反应工程与工艺》1997,13(2):190-193
在全混釜批式反应器(CSTR)中研究了Y型分子筛催化剂作用下苯与长直链烯烃的烷基化反应,探讨了投料比对烯烃转化率以及温度对产物选择性的影响。在所设计的新型液固循环反应-再生流化床反应系统中,用工业原料验证了在分子筛催化剂作用下采用该反应系统连续合成长直链基苯的工业可行性 相似文献
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下行床反应器用于重油催化裂解制取低碳烯烃 总被引:1,自引:1,他引:0
建立了一套下行式循环流化床反应装置,利用此装置进行了重油催化裂解制取低碳烯烃的实验研究.以中间基丙烷脱沥青油(DAO)为原料、工业CHP-1分子筛平衡剂为催化剂,主要考察了下行床反应器中反应温度和剂油比对实验结果的影响.试验表明:当以丙烯、丁烯为目标产物时,反应温度存在最佳值,剂油比越大低碳烯烃收率越高.由于下行床具有短停留时间、气固流动更均匀和返混小的优点,能获得更高的产品收率,使干气收率受到抑制.试验结果说明下行床反应器是一种适合于石油烃类裂解工艺过程的反应器形式. 相似文献
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在绝热固定床实验反应器中对苯和乙烯在 AF-5分子筛催化剂上进行的烷基化反应的失活动力学作了研究。初步考察表明乙烯和苯都会引起失活,但乙烯引起的失活是主要的。在和工业反应器类似的操作条件下系统测定了由催化剂失活引起的乙烯转化率随操作时间的变化。所得数据将用于建立失活动力学模型。 相似文献
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苯酚直接羟化制备苯二酚催化剂失活过程研究 总被引:2,自引:0,他引:2
催化剂失活是一个复杂的物理和化学过程,失活原因多种多样,催化剂失活对催化过程的工艺流程、设备以及操作条件等的选择起着决定性的作用。本文对苯酚羟化用铁复合氧化物催化剂的失活情况进行了研究,考察了催化剂的寿命和催化剂活性随时间的变化关系,改变实验条件进行了催化剂活原因的分析。结果表明,催化剂8h左右开始失活,催化剂完全时间约为70h,催化剂失活的主要原因是由于活性组分从催化剂载体上流失引起。为了计算连续搅拌反应器中化催化剂的活性分布,便于反应器的设计和操作优化,关联了催化剂活性与时间的函数关系。 相似文献
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MFI-type zeolite membranes were hydrothermally synthesized as a thin layer on macroporous α-alumina discs coated with 1µm MFI-type seed crystals as seed. The effect of soda (Na2O) concentration on the morphology of the membranes was investigated. Soda concentration, and thus the hydroxyl ion concentration, was changed between 0.25 and 6.5 mol/mol gel. At low soda concentrations the crystals forming the layer exhibited mostly (h0h)/c-axis orientation, but at high soda concentrations a membrane layer formed from randomly oriented crystals. The membranes showed high H2/n-butane ideal selectivity of 476 and 36 at 25°C and 150°C, respectively. 相似文献