Fischer-Tropsch studies in a 3D-printed stainless steel microchannel microreactor coated with cobalt-based bimetallic-MCM-41 catalysts
Fischer-Tropsch studies in a 3D-printed stainless steel microchannel microreactor coated with cobalt-based bimetallic-MCM-41 catalysts
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DOI：
10.1016/j.cattod.2020.02.020
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发表时间：
2020-12-01
期刊：
影响因子：
5.3
通讯作者：
Kuila, Debasish
中科院分区：
文献类型：
--
作者：
Mohammad, Nafeezuddin;Abrokwah, Richard Y.;Kuila, Debasish
使用3D打印的不锈钢（SS）微反应器进行费托（FT）合成，该微反应器包含尺寸为500 μ m x 500 μ m x 2.7 cm的通道，以研究Fe、Ru和Ni对Co-MCM-41催化剂的影响。采用一锅水热法合成了15 % Co-MCM-41、10%Co5%Ru MCM-41、10%Co5%Ni MCM-41和10%Co5%Fe MCM-41单钴基和双钴基催化剂，并用SEMEDX、TEM、TPR、FTIR、XPS、低角和广角XRD等技术对催化剂进行了表征。所有催化剂都表现出高的比表面积，而没有失去有序的介孔结构，这一点通过大的BET比表面积（400-1000 m（2）/g）和低角度XRD数据证实。金属纳米粒子的范围为35-50 nm，并且很好地分散在MCM-41的六方基质中。TPR数据表明，除了钴的金属氧化物之外，所有其他金属氧化物都可以在低于600 ℃下用H-2还原。钴最有可能以硅酸钴的形式存在，它只能在650摄氏度以上的温度下用H-2还原。采用浸渍法将催化剂与聚乙烯醇（PVA）混合均匀地涂覆在SS反应器的微通道上。FT合成的催化性能在SS微反应器中在常压下在180-300 ° C的温度范围内进行，H2/CO摩尔比为3。在FT合成中，第二金属在Co-MCM-41骨架中的掺入和操作温度对CO转化率和C1-C4烷烃的选择性有显著影响。虽然CoFe-MCM-41在240 ° C下获得74%的最高CO转化率，但CoRu-MCM-41在240 ° C下和CoFe-MCM-41在210 ° C下分别观察到对丁烷（11%）和丙烷（39%）的最高选择性。催化剂的失活速率顺序为：CoRu-MCM-41> CoNi-MCM-41 > Co-MCM-41 > CoFe-MCM-41，表明CoFe-MCM-41催化剂的长期稳定性最好。
Fischer-Tropsch (FT) synthesis was carried out using 3D-printed stainless steel (SS) microreactors, containing channels of dimensions 500 mu m x 500 mu m x 2.7 cm, to study the effect of Fe, Ru, and Ni on Co-MCM-41 catalyst. The mono and bimetallic cobalt-based catalysts: 15 % Co-MCM-41, 10 %Co5% Ru MCM-41, 10 %Co 5%Ni MCM41, and 10 %Co 5%Fe MCM-41 were synthesized using one-pot hydrothermal method and characterized by SEMEDX, TEM, TPR, FTIR, XPS, and low and wide angle XRD techniques. All the catalysts exhibited high surface area without the loss of ordered mesoporous structure as confirmed by large BET surface areas (400-1000 m(2)/g) and low angle XRD data. The metal nanoparticles were in the range of 35-50 nm and well dispersed in a hexagonal matrix of MCM-41. TPR data indicate that all other metal oxides except that of cobalt can be reduced with H-2 below 600 degrees C. Cobalt is present most likely as cobalt silicates that can only be reduced with H-2 at a temperature over 650 degrees C. The microchannels of SS reactor were uniformly coated by dip coating a slurry of the catalyst with polyvinyl alcohol (PVA). The catalytic performance for FT synthesis was carried out in the SS microreactor at atmospheric pressure in the temperature range of 180-300 degrees C with H-2/CO molar ratio of 3. Incorporation of the second metal in the Co-MCM-41 framework and the operating temperature had a significant effect on CO conversion and selectivity towards C1-C4 alkanes in FT synthesis. While the highest CO conversion of 74 % was obtained for CoFe-MCM-41 at 240 degrees C, the highest selectivity towards butane (11 %) and propane (39 %) was observed for CoRu-MCM-41 at 240 degrees C and CoFe-MCM-41 at 210 degrees C, respectively. The rate of deactivation of the catalysts-followed the order: CoRu-MCM-41 > CoNi-MCM-41 > Co-MCM-41 > CoFe-MCM-41, indicating that CoFe-MCM-41 is the most suitable catalyst for F-T synthesis in terms of long term stability.