钴基催化剂的制备及费托合成反应性能的研究

发布时间：2018-05-14 06:57

  本文选题：钴基催化剂 + 载体　； 参考：《浙江工业大学》2016年硕士论文

【摘要】：费托合成(Fischer-Tropsch Synthesis,简称FTS)是将生物质、煤、天然气等气化的合成气(CO+H_2)催化转化为清洁的液体燃料及高附加值化学品的重要途径,被认为是解决我国能源供应不足的最有效途径之一。钴基催化剂因其具有良好的催化活性和高碳烃的选择性,不易失活和积碳,水煤气变换反应活性低等特点,被认为是费托合成反应最具有发展前途的催化剂之一。本文采用等体积浸渍法制备了费托合成负载型钴基催化剂,在固定床反应器上评价催化剂的催化活性,以CO转化率和C_5-C_(11)汽油馏分烃选择性为催化剂催化活性的评价指标,筛选出催化活性较好的催化剂,并对催化剂进行了BET、XRD、FT-IR、TPR、TPD等手段的表征。本论文的具体研究工作和主要结论如下:(1)分别考察了氧化物载体(SiO_2)、碳材料载体(CNTs)、纯硅分子筛载体(MCM-41、SBA-15)以及酸性分子筛载体(Hβ、HY、HZSM-5、mordenite)对费托合成钴基催化剂催化活性的影响。结果表明:稳定状态下Co/SBA-15催化剂的CO转化率最高,为92.6%。稳定状态下Co/HZSM-5催化剂的C_5-C_(11)烃选择性最高,为48.3%。以CO转化率、C_5-C_(11)汽油馏分烃选择性为催化剂催化活性的评价指标,筛选出了催化剂对CO转化率最高的载体为SBA-15,对C_5-C_(11)汽油馏分烃选择性最高的载体为HZSM-5。(2)考察了载体HZSM-5硅铝比(SiO_2/Al_2O_3=25、38、50、80和200)以及合成Co/HZSM-5催化剂的焙烧温度对负载型钴基催化剂费托合成反应活性的影响。结果表明:相比Co/HZSM-5(SiO_2/Al_2O_3=25、38、50和80)催化剂,Co/HZSM-5(SiO_2/Al_2O_3=200)催化剂表现出相对最高的CO转化率和C_5-C_(11)烃选择性,分别为84.1%、52.8%。以HZSM-5(SiO_2/Al_2O_3=200)为载体,发现不同焙烧温度合成的Co/HZSM-5催化剂对费托合成活性也具有明显的影响。对比Co/HZSM-5(300℃、400℃、500℃)催化剂,Co/HZSM-5(400℃)催化剂表现出相对最高的CO转化率和C_5-C_(11)烃选择性,分别为84.1%、52.8%。(3)在前期研究的基础上,筛选出其中催化剂催化性能较优的两个载体为SBA-15和HZSM-5。以不同硅铝比的HZSM-5分子筛(SiO_2/Al_2O_3=50、80、200)与SBA-15组成的复合载体作为新的载体,分别考察了HZSM-5不同硅铝比、SBA-15与HZSM-5不同质量比对复合催化剂费托反应活性的影响。结果表明:相比Co/SZ-50-4、Co/SZ-80-4催化剂,Co/SZ-200-4催化剂表现出相对较高的CO转化率和C_5-C_(11)烃选择性,分别为93.0%、51.8%。对比Co/SZ-200-1、Co/SZ-200-2、Co/SZ-200-3、Co/SZ-200-4催化剂,Co/SZ-200-4催化剂的CO转化率和C_5-C_(11)烃选择性最高,分别为93.0%、51.8%。(4)稳定状态下催化剂的C5~C11烃收率为:Co/SZ-200-4Co/HZSM-5-200Co/SBA-15,依次为48.2%、44.4%、38.2%,其中Co/SZ-200-4催化剂的C5~C11烃收率最高,为48.2%。对比Co/HZSM-5-200和Co/SBA-15催化剂,以复合载体为新的载体制备的Co/SZ-200-4催化剂的C5~C11烃收率明显提高。
[Abstract]:Fischer-Tropsch Synthesis (FTS) is an important way to catalyze the conversion of biomass, coal, natural gas and other gasified syngas to clean liquid fuel and high value-added chemicals. It is considered to be one of the most effective ways to solve the shortage of energy supply in China. Cobalt based catalysts are considered as one of the most promising catalysts for Fischer synthesis because of their good catalytic activity, high hydrocarbon selectivity, low activity of water gas shift reaction and so on. In this paper, supported cobalt based catalyst for Fischer synthesis was prepared by equal volume impregnation method. The catalytic activity of the catalyst was evaluated in a fixed bed reactor. The catalytic activity of the catalyst was evaluated by using CO conversion and the selectivity of C _ 5-C _ (11) gasoline fraction as the catalytic activity. The catalyst with good catalytic activity was screened and characterized by BET-XRDX FT-IRT-TPR-TPD. The specific research work and main conclusions of this thesis are as follows: (1) the effects of oxide support SiO2H, carbon material carrier CNTsN, pure silica molecular sieve carrier MCM-41 SBA-15) and acidic molecular sieve carrier HYYHZSM-5mordenite on the catalytic activity of Cobalt based catalyst for Fischer synthesis were investigated. The results showed that the CO conversion of Co/SBA-15 catalyst was the highest, 92.6g under stable condition. The selectivity of C _ S _ 5-C _ S _ (11) for Co/HZSM-5 catalyst is the highest at 48.3% under stable condition. The selectivity of CO conversion to C _ 5-C _ S _ (11) gasoline fraction was taken as the evaluation index of the catalytic activity of the catalyst. The carrier with the highest CO conversion was SBA-15, and the carrier with the highest hydrocarbon selectivity for gasoline fraction was HZSM-5.02) the carrier HZSM-5 SiO2 / Al _ 2O _ 2O _ 2 / Al _ 2O _ 2O _ 3O _ 2O _ 3 / Si _ 2O _ 3 / S _ 2O _ 3O _ 2O _ 3 and the calcination temperature of the synthetic Co/HZSM-5 catalyst were used to investigate the effect of calcination temperature on the supported cobalt-based catalyst. The effect of Fischer on the activity of synthetic reaction. The results show that compared with Co/ HZSM-5SiO _ (2 / S) / S _ 2AlS _ 2O _ 3 / S _ 3 / S _ 3 / T _ 3) catalyst Co/ H _ ZSM-5 / Si _ 2O _ 3 _ T _ (2 / 20) catalyst shows the highest CO conversion and C _ 5-C _ (11) hydrocarbon selectivity, respectively, which are 84.1and 52.8%, respectively, in comparison with the Co/ HZSM-5 / S _ (20) / C _ (5) C _ (11) C _ (5) C _ (11). On the basis of HZSM-5SiOS _ 2 / Al _ 2O _ 2O _ 3 / 200), it was found that Co/HZSM-5 catalysts with different calcination temperatures also had a significant effect on the activity of Fischer synthesis. Compared with the Co/HZSM-5(300 鈩，

本文编号：1886807