Noble Metal Catalyst For Hydrocracking Of F-T Wax To Middle Distillate

LTFT(Low Temperature Fischer-Tropsch Synthesis) has more than 40% of the products is wax. The Fischer-Tropsch wax mostly made of n-paraffins and olefins. Fischer-Tropsch wax has the characteristics of sulphurless, nitrogenfree, metal-free and less content of aromatics. LTFT wax has a very high cetane numbers (usually>75) but the solidifying temperature very low. Thus, one of most important effective ways in LTFT waxes upgrading is development hydrocracking catalysts for produce high quality fuel through hydrocracking of LTFT wax.In this study,56# half-refined paraffin was used as a model raw material to evaluate the activities of various catalysts. First of all,1%(wt.) Pd loading catalyst supported on SAB (Pd/SAB) were prepared by an impregnation method, and then for use for produce middle distillate (C5-C15) through hydrocracking of paraffin wax. Later the process conditions were studied. The experimental results show that the Pd/SAB catalyst in the conditions H2/wax=1000,3.5MPa, WHSV=2, T= 300℃, can got a 78.58% conversion, besides of gasoline and diesel selective reached 48.29%. Pd/SAB catalyst life shows that the conversion dropped to below 50% in 37h. Secondly, the hydrocracking activities of Pt/SAB catalysts were investigated and the amount of Pt contend were discussed. In this series of catalysts, Pt-0.008/SAB showed high conversion of 90.74% and the middle distillates selectivity was 80.11%.In this paper, Two kinds of Ni fiber package Pt/SAB catalysts were prepared. Through the experiment Pt/SABb catalyst shows a higher performance. in the condition WHSV=1h-1, 320℃, the Pt/SABa catalyst's conversion was only 9.05%, even when the reaction temperature up to 370℃, the conversion was 30.96%. Pt/SABb catalyst in the temperature 350℃, reaction conversion was 54.54%; When the temperature up to 370℃, the conversion reached 75.08%. The catalysts were characterized by TEM, SEM, N2 Adsorption-Desorption and NH3-TPD. Also the relations between the surface properties and activity were discussed. The calcination process made active metal gathered, and pore structure changes at the same time, specific surface area reduced made the main reasons of activity decline. For single pipe fixed bed reactor, used FLUENT software simulated the reaction processes, and the result showed similar to experimental results.