共查询到19条相似文献,搜索用时 62 毫秒
1.
2.
采用浸渍法制备了负载型钴基催化剂,Co的质量分数为16.7%.考察了载体活性炭、活性氧化铝、硅胶和γ-Al2O3对催化剂性能的影响.催化剂的催化活性依Co/γ-Al2O3、Co/硅胶、Co/活性炭和Co/活性氧化铝下降,烃产物的链增长能力按Co/γ-Al2O3、Co/硅胶、Co/活性氧化铝和Co/活性炭的次序减弱.Co/活性炭催化剂有利于低碳烃的生成,Co/γ-Al2O3利于重质烃的生成.随着反应温度的提高,副产物CH4、CO2的选择性增加,链增长能力下降,低碳烃含量增加. 相似文献
3.
概述了co基费托合成催化剂的制备方法,介绍了Co盐种类、浸渍方法、浸渍溶液的pH值、Co盐溶剂、金属Co负载量和干燥温度等制备条件对Co基催化剂活性的影响,介绍了Co基催化剂的改性方法。并在此基础上对Co基催化剂今后的研究发展方向进行了展望。 相似文献
4.
5.
6.
7.
8.
9.
采用浸渍法制备了ZrO2改性的的硅胶催化剂载体,并以该载体制备了蛋壳型催化剂,利用BET,SEM和EDS等考察了钴基催化剂的结构和还原性能.结果表明,ZrO2改性的蛋壳型催化剂具有更好的比表面性能;ZrO2改性的载体有利于提高催化剂的分散程度、催化活性及C5+选择性.在温度250℃,压力2MPa,空速500h-1条件下,蛋壳型催化剂上CO转化率可达到89.87%~96.58%,C5+选择性为76.8%~84.7%. 相似文献
10.
11.
12.
13.
Hasan Oliaei Torshizi Ali Nakhaei Pour Ali Mohammadi Yahya Zamani Seyed Mehdi Kamali Shahri 《Frontiers of Chemical Science and Engineering》2021,15(2):299-309
In this paper,a series of cobalt catalysts supported on reduced graphene oxide(rGO)nanosheets with the loading of 5,15 and 30 wt-%were provided by the impregnation method.The activity of the prepared catalysts is evaluated in the Fischer-Tropsch synthesis(FTS).The prepared catalysts were carefully characterized by nitrogen adsorption-desorption,hydrogen chemisorption,X-ray diffraction,Fourier transform infrared spectroscopy,Raman spectroscopy,temperature programmed reduction,transmission electron microscopy,and field emission scanning electron microscopy techniques to confirm that cobalt particles were greatly dispersed on the rGO nanosheets.The results showed that with increasing the cobalt loading on the rGO support,the carbon defects are increased and as a consequence,the reduction of cobalt is decreased.The FTS activity results showed that the cobalt-time yield and turnover frequency passed from a maximum for catalyst with the Co0 average particle size of 15 nm due to the synergetic effect of cobalt reducibility and particle size.The products selectivity results indicated that the methane selectivity decreases,whereas the C5+selectivity raises with the increasing of the cobalt particle size,which can be explained by chain propagation in the primary chain growth reactions. 相似文献
14.
氧化物助剂促进的钴基催化剂具有费托合成反应活性和长链烃选择性高等特点,是高选择性地获得馏分油的关键,具有良好的应用和研究价值。本文针对氧化物助剂对钴基催化剂的促进作用,综述了氧化物助剂对钴基催化剂的结构、稳定性以及费托合成反应性能的影响,详细分析了氧化物助剂对钴基催化剂的还原性能和分散度的影响, 同时介绍了影响氧化物助剂促进作用的因素,重点讨论了氧化物助剂的促进作用机理。并对如何更好地发挥氧化物助剂在钴基催化剂中的促进作用进行了展望:应加强氧化物助剂对钴基催化剂促进作用机理的基础研究,并且重视影响氧化物助剂促进作用的因素。 相似文献
15.
16.
Step-change experiments between H2, CO, and syngas mixtures with time resolution of ca. 0.3 s were undertaken to critically test mechanisms proposed in the literature for the Fischer-Tropsch synthesis. A silica-supported cobalt catalyst was used. Results suggest C2+ olefins and branched paraffins form from a carbon deposit on the catalyst surface. Two pathways appear to exist for methane formation. The first of these is from the carbon deposit through direct hydrogenation and through hydrogenolysis of the long-chain materials formed. The second pathway is hydrogenation of strongly adsorbed CO. 相似文献
17.
为降低费托合成钴催化剂成本,提高费托合成钴催化剂的稳定性和寿命,分析了费托合成钴催化剂的失活与再生机理,论述了费托合成钴催化剂的再生方法。结果表明,中毒、烧结长大、积碳、氧化及固相反应是造成费托合成钴催化剂失活的主要原因。通过净化原料气、调节钴与载体相互作用、调整催化剂配方及工艺条件、控制钴颗粒尺寸及体系中水和H2的分压比等措施可以提高催化剂稳定性和寿命。通过脱蜡、氧化、还原可实现催化剂再生,氧化是再生的关键步骤,要注意氧化过程中升温速率、热量移除等问题;多次的氧化和还原过程可增加再生催化剂中金属钴与还原助剂的均匀性,提高再生催化剂的活性。 相似文献
18.
Different cycling strategies are explored to see if carbon chain growth can be enhanced and methane formation suppressed. Of the strategies considered, bang-bang cycling between H2 and CO feeds substantially increased the consumption of CO and H2, but the formation of higher hydrocarbons and olefins was reduced. The best strategy for longer chain hydrocarbons suitable for jet or diesel fuels was found to be cycling between syngas mixtures. None of the cycling strategies was able to produce C8+ or low-molar mass olefin yields that matched yields found in steady-state operation. 相似文献