摘要
以亲水硅胶DegussaA300和疏水硅胶DegussaR106作为催化剂载体，采用等体积浸渍法制备了一系列钴基催化剂。利用MS、XRD、BET、FT—IR、TPR等手段考察了载体热稳定性，催化剂表面物相结构和还原性能等物化性能。结果表明，载体表面有机基团对催化剂中Co3O4尺寸大小有影响，有机基团对载体表面羟基的取代使得金属钴与载体的作用力减弱，有利于金属团聚为较大的颗粒。费-托反应结果表明，亲水硅胶性制得的催化剂通过后处理引入甲基后，造成催化剂活性下降，C18＋的选择性下降，但使烃分布集中在C5-C18，这是由于表面甲基的空间位阻作用不利于反应中的吸附过程和链增长过程。由疏水载体制备的催化剂虽然钴颗粒较大，但是由于催化剂制备过程中部分有机基团的烧结，对催化剂活性产生了较大的负面影响，使催化活性降低，重质烃选择性明显降低。
A series of cobalt-based catalysts were prepared by incipient wetness impregnation, using Degussa A300 and R106 as supports. The physico-chemical properties of samples were characterized by XRD, BET, TPR, TPO and FT-IR. Fischer-Tropsch （F-T） reaction was carded out in a fixed-bed reactor under the conditions of n （ H2 ） / n （CO）=2.0, GHSV = 1 500 h^-1, p = 2.0 MPa and t = 210℃ - 260℃. The investigation showed that there was some relation between the Co3 O4 size and the coverage of hydroxyl on the surface of supports. Organic groups covering hydroxyl on surface of support weakened the interaction strength of support-precursor combinations, and that favored the formation of Co3O4 with bigger crystallite size. The sintering of organic groups made the reaction activity and the selectivity for heavy hydrocarbons decrease.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2006年第3期343-347,共5页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金(20303026
20590361)
国家重点基础研究发展规划(973计划
2005CB221402)
关键词
费-托合成
硅胶
有机基团
改性
钴基催化剂
Fischer-Tropsch synthesis
silica
organic groups
modification
cobalt-catalyst
