介孔碳材料负载钴基费托合成催化剂制备研究
发布时间：2018-11-09 18:23
【摘要】：随着石油资源的日渐枯竭,以它为原料的汽油、柴油等液态燃料能否被持续和稳定地供应成了消费市场的重大隐忧,以煤、天然气、生物质转化制取液态燃料技术受到越来越多的关注,而费托合成(F-T)是实现这种转化的重要途径之一。钴(Co)基催化剂具有较高的CO加氢活性和F-T反应链增长能力,高转化率下具有更高的生产能力,适用于氢碳比更高的反应体系,反应过程较为稳定不易积碳和中毒,产物中含氧化合物少,对水气变换反应不敏感、活性低。因此Co基催化剂被视为低温F-T反应制取长链烃的首要选择,具有良好的应用前景。本文重点考察了介孔碳载体的制备方法,介孔碳载体的孔道对于Co基催化剂的F-T反应活性以及产物选择性的影响、分子筛SBA-15载体修饰改性对于Co基催化剂F-T合成反应活性以及产物选择性的影响。不同催化剂对于汽油段(C5-C10)、柴油段(C10-C20)产物选择性有着较大的差异。通过前期的制备工作以及X射线衍射(XRD)、N2物理吸附-脱附、程序升温还原(TPR)、扫描电镜(SEM)等表征手段,得到了以下结果:(1)以SBA-15为模板,蔗糖为碳源,通过改变SBA-15制备过程中的晶化、老化温度,制备出了一系列孔径、比表面积渐变的介孔碳材料,并以其为Co基催化剂的载体,研究了其孔径、比表面积大小对Co基催化剂F-T反应性能的影响。所制备的碳材料孔径介于3.42-5.14nm、比表面积介于410.50-1141.00m2·g-1范围内。催化剂F-T反应性能测试表明,载体孔径、比表面积对催化剂F-T反应活性有着重要的影响;孔径为5.14nm、比表面积为1003.68 m2·g-1的介孔碳载体所制备出的催化剂显示出了最高的F-T反应活性以及C5+产物选择性,其中C10-C20的选择性达到了56.19%。(2)通过往分子筛SBA-15孔道中填充不同质量比的蔗糖、并以碳化,探讨经过不同质量蔗糖修饰的SBA-15载体对于Co基催化剂F-T反应活性以及产物选择性的影响。不同质量比的蔗糖的加入使得Co基催化剂的反应活性有了一定幅度的下降,但F-T反应产物分布发生了明显的前移。在催化剂Co/SBA-15C中,随着蔗糖加入量的增加,催化剂的CO转化率以及产物的C5+选择性均呈现出先减小后增大再减小的趋势,Co/SBA-15C3有着最高的C5+选择性,其中C5-C10选择性高达55.85%。(3)以工业通用级聚苯乙烯(PS,PG-22)为成膜材料,采用呼吸图案法制备了多孔膜,并利用扫描电镜(SEM)对多孔膜的形貌进行了观察,得出了制备有序多孔膜的适宜条件为:在环境温度为25℃和用甲苯为溶剂时,聚合物浓度为25mg/mL,用量为0.8mL,环境湿度85%(相对湿度),并保持静态气氛。采用PS溶液多次涂覆方法可以增加多孔膜厚度。在此基础上利用PS有序多孔膜对SBA-15进行了修饰,发现修饰后的催化剂由于孔道的堵塞以及还原度的降低导致了催化剂的F-T反应活性较低,产物中CO、CH4选择性较高,C5+选择性降低。
[Abstract]:With the gradual depletion of petroleum resources, whether the liquid fuels such as gasoline, diesel and other liquid fuels, such as gasoline and diesel, which are used as raw materials, can be continuously and stably supplied has become a major hidden concern in the consumer market. With coal and natural gas, More and more attention has been paid to the technology of biomass conversion to produce liquid fuel, and Fischer synthesis (F-T) is one of the important ways to achieve this conversion. Cobalt (Co) based catalyst has high CO hydrogenation activity and F-T reaction chain growth ability, and has higher production capacity under high conversion rate. It is suitable for the reaction system with higher hydrogen-carbon ratio, and the reaction process is stable and not easy to deposit carbon and poisoning. The product contains less oxygen compounds, is insensitive to water gas shift reaction, and has low activity. Therefore, Co catalyst is regarded as the first choice of low temperature F-T reaction to produce long chain hydrocarbon, which has a good application prospect. The preparation method of mesoporous carbon carrier and the influence of the pore channel of mesoporous carbon carrier on the F-T reaction activity and product selectivity of Co based catalyst were investigated. Effects of modification of molecular sieve SBA-15 support on F-T synthesis activity and product selectivity of Co-based catalyst. The selectivity of different catalysts for gasoline stage (C5-C10) and diesel oil stage (C10-C20) was different. The results were as follows: (1) SBA-15 was used as template, sucrose as carbon source, and (XRD), N2 was physically adsorbed and desorbed by X-ray diffraction (XRD), and (TPR), scanning electron microscopy (SEM) was used to reduce temperature programmed reduction, the results were as follows: (1) using SBA-15 as template, sucrose was used as carbon source. A series of mesoporous carbon materials with varying pore size and specific surface area were prepared by changing the crystallization and aging temperature during the preparation of SBA-15. The pore size of mesoporous carbon materials was studied by using it as the carrier of Co based catalyst. Effect of specific Surface area on the performance of Co based Catalysts for F-T reaction. The pore size of the carbon materials was 3.42-5.14 nm and the specific surface area was in the range of 410.50-1141.00m2 g ~ (-1). The performance of the catalyst F-T reaction showed that the pore size and specific surface area of the catalyst had important effects on the activity of the catalyst F-T reaction. The catalyst prepared by the mesoporous carbon carrier with a pore size of 5.14 nm and a specific surface area of 1003.68 m2 g ~ (-1) showed the highest F-T reaction activity and the selectivity of C _ 5 products. The selectivity of C10-C20 reached 56.19. (2) by filling different mass ratios of sucrose in the pore of molecular sieve SBA-15 and carbonizing, The effects of sucrose modified SBA-15 support on the F-T reaction activity and product selectivity of Co based catalyst were investigated. The addition of sucrose with different mass ratio decreased the activity of Co catalyst to a certain extent, but the product distribution of F-T catalyst moved forward obviously. In the catalyst Co/SBA-15C, with the increase of sucrose content, the conversion of CO and the C5 selectivity of the product showed a tendency of decreasing first, then increasing, then decreasing. Co/SBA-15C3 had the highest C5 selectivity. The selectivity of C5-C10 is as high as 55.85. (3) porous membranes were prepared by respiratory pattern method using industrial polystyrene (PS,PG-22) as film forming material. The morphology of the porous membrane was observed by scanning electron microscope (SEM). The optimum conditions for the preparation of ordered porous membrane were obtained as follows: the concentration of polymer was 25 mg / mL and the amount of polymer was 0.8 mL when the ambient temperature was 25 鈩，
本文编号：2321204
[Abstract]:With the gradual depletion of petroleum resources, whether the liquid fuels such as gasoline, diesel and other liquid fuels, such as gasoline and diesel, which are used as raw materials, can be continuously and stably supplied has become a major hidden concern in the consumer market. With coal and natural gas, More and more attention has been paid to the technology of biomass conversion to produce liquid fuel, and Fischer synthesis (F-T) is one of the important ways to achieve this conversion. Cobalt (Co) based catalyst has high CO hydrogenation activity and F-T reaction chain growth ability, and has higher production capacity under high conversion rate. It is suitable for the reaction system with higher hydrogen-carbon ratio, and the reaction process is stable and not easy to deposit carbon and poisoning. The product contains less oxygen compounds, is insensitive to water gas shift reaction, and has low activity. Therefore, Co catalyst is regarded as the first choice of low temperature F-T reaction to produce long chain hydrocarbon, which has a good application prospect. The preparation method of mesoporous carbon carrier and the influence of the pore channel of mesoporous carbon carrier on the F-T reaction activity and product selectivity of Co based catalyst were investigated. Effects of modification of molecular sieve SBA-15 support on F-T synthesis activity and product selectivity of Co-based catalyst. The selectivity of different catalysts for gasoline stage (C5-C10) and diesel oil stage (C10-C20) was different. The results were as follows: (1) SBA-15 was used as template, sucrose as carbon source, and (XRD), N2 was physically adsorbed and desorbed by X-ray diffraction (XRD), and (TPR), scanning electron microscopy (SEM) was used to reduce temperature programmed reduction, the results were as follows: (1) using SBA-15 as template, sucrose was used as carbon source. A series of mesoporous carbon materials with varying pore size and specific surface area were prepared by changing the crystallization and aging temperature during the preparation of SBA-15. The pore size of mesoporous carbon materials was studied by using it as the carrier of Co based catalyst. Effect of specific Surface area on the performance of Co based Catalysts for F-T reaction. The pore size of the carbon materials was 3.42-5.14 nm and the specific surface area was in the range of 410.50-1141.00m2 g ~ (-1). The performance of the catalyst F-T reaction showed that the pore size and specific surface area of the catalyst had important effects on the activity of the catalyst F-T reaction. The catalyst prepared by the mesoporous carbon carrier with a pore size of 5.14 nm and a specific surface area of 1003.68 m2 g ~ (-1) showed the highest F-T reaction activity and the selectivity of C _ 5 products. The selectivity of C10-C20 reached 56.19. (2) by filling different mass ratios of sucrose in the pore of molecular sieve SBA-15 and carbonizing, The effects of sucrose modified SBA-15 support on the F-T reaction activity and product selectivity of Co based catalyst were investigated. The addition of sucrose with different mass ratio decreased the activity of Co catalyst to a certain extent, but the product distribution of F-T catalyst moved forward obviously. In the catalyst Co/SBA-15C, with the increase of sucrose content, the conversion of CO and the C5 selectivity of the product showed a tendency of decreasing first, then increasing, then decreasing. Co/SBA-15C3 had the highest C5 selectivity. The selectivity of C5-C10 is as high as 55.85. (3) porous membranes were prepared by respiratory pattern method using industrial polystyrene (PS,PG-22) as film forming material. The morphology of the porous membrane was observed by scanning electron microscope (SEM). The optimum conditions for the preparation of ordered porous membrane were obtained as follows: the concentration of polymer was 25 mg / mL and the amount of polymer was 0.8 mL when the ambient temperature was 25 鈩，
本文编号：2321204
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