investigation of co-zsm-5 catalyst in fischer-tropsch synthesis for fuel production

Due to high activity of cobalt metal in syngas conversion to higher hydrocarbons, supported cobalt catalysts have been widely used for fischer-tropsch synthesis (fts) reaction. cobalt catalyst is very active to produce long chain normal paraffin and also it shows high resistance to deactivation[1,2]. the present of strong acid sites in co/h-zsm-5 influence mainly the selectivity to the c5-c12 hydrocarbons. the application of cozsm-5 having in its structure weak acid sites exhibited greater selectivity to c5-c8 hydrocarbons [3,4]. co-zsm-5 catalyst was prepared by a wet impregnation method. the co loading was 15 wt.% on the catalyst. after evaporating to eliminate water, the samples were dried at 120 oc for 20 h and calcined at 400 oc for 3 h. the catalyst was pressed into pellet, crushed and sieved 16-30 mesh . the catalysts were characterized using xrd, h2-tpr,semand bet techniques.the effect of zsm-5 on catalytic performance of co catalyst was studied in a fixed bed reactor at the following conditions: 220°c, 25 atm, h2/co of 2 and gas space velocities of 1.8 nl/(g cat.h). the catalyst was activated in situ with hydrogen at 400 °c for 16 h. co conversion and product distribution was calculated by results of gas chromatography. selectivities of light hydrocarbon products increased with adding of zsm-5 zeolite into the catalyst, whereas selectivity of heavy hydrocarbons decreased.