Fuel production by hydrotreating of triglycerides on NiMo/Al2O3/F catalyst

The importance and the economical production of the so-called bio gas oils from triglycerides are presented. They are second generation bio-fuels containing mainly normal and isoparaffin and have gas oil boiling range. The investigation of their producibility was carried out on a Ni(2.3%)Mo(13.7%)/Al2O3/F catalyst. Based on the results the conversion of triglycerides (sunflower oil containing dimethyl disulphide as sulphiding agent), the yield of the target product, furthermore the type and ratio of the deoxygenation reactions and the degree of the paraffin isomerization were determined as a function of the process parameters. On the investigated sulphided catalyst favourable process parameters were found, (350–370 °C, 20–40 bar, 1.0 h−1 LHSV, 500 Nm3/m3) where the conversion of triglycerides was over 90% and the yield of the high n- and isoparaffin containing (>99.9%) gas oil boiling range target fraction was relatively high (73.2–75.6%). It was concluded that during the deoxygenation of triglycerides the reduction as well as the decarboxylation/decarbonylation reactions took place, namely C18 and C17 paraffins were formed, too, on the applied catalyst. But the yield of the target fractions did not achieve the theoretical values (81.4–86.5%) at the advantageous process parameters. That is why it is necessary to separate and recirculate the heavy fraction. The isoparaffin content of the target products was significantly higher than the products derived on non-fluorinated catalysts and thus their flow properties are favourable in the aspect of application.

► Sunflower oil was converted on Ni(2.3%)Mo(13.7%)/Al2O3/F catalyst. ► The formation of normal and isoparaffin was investigated in one catalytic step. ► Favourable process parameters were 350–370̊C, 20–40 bar, 1.0 h−1 LHSV and 500 Nm3/m3. ► Products of relatively high isoparaffin content had favourable flow properties. ► Cetane number of the main products was excellent (87).