PRODUCTION OF ALTERNATIVE AVIATION BIOFUELS FROM CATALYTIC PYROLYSIS OF WASTE VEGETABLE OIL IN A PILOT-SCALE CONTINUOUS SCREW PYROLYZER

Abstract

This research aims to produce aviation biofuel using waste from vegetable oil and animal fat by catalytic pyrolysis in a continuous pilot screw reactor. The raw materials used were waste from palm oil, used cooking oil and animal fat, which were generally composed of fatty acids and converted to products by calcined dolomite as the catalyst. The research work was divided into two parts. The 1^st part was the experiment in a bench reactor to determine the optimum conditions for use of waste palm oil and its reaction temperature and catalyst loading. The results of this part showed the optimum reaction temperature and catalyst loading as 425^๐C and 3 wt%, respectively. The product yields of liquid, solid and gas were 68.22, 3.43 and 28.50 wt%, respectively, whereas the composition in liquid was naphtha 14.70 wt%, kerosene 23.72 wt%, diesel 51.24 wt%, and residue 10.32 wt%. The 2^nd part was the production of liquid fuel from the raw material mentioned above in a pilot screw reactor with a waste palm oil feed rate of 800 kg/d. The optimum temperature, 425^๐C and 3 wt% catalyst loading from the 1^st part, were set up to operate the pilot reactor. The liquid, solid and gas yields of this operation using waste palm oil were 66.58, 8.08 and 25.34 wt%, respectively. The composition of the liquid product was consisted of naphtha 21.63 wt%, kerosene 23.57 wt%, diesel 48.22 wt%, and residue 5.58 wt%. The experimental results of 3 types of raw material in the pilot reactor gave a product yield range of 61-69 wt%. The composition in liquid biofuel was composed of naphtha, kerosene, diesel and fuel oil, in which kerosene proportion approximately of 21.95 to 23.90%. The estimated cost per kg of kerosene (aviation biofuel) for the production of 800 kg/d, including operating and investment costs, was 34.75 baht/kg, and the actual selling price of sustainable aviation fuel (SAF) from hydrocracking process is 133 baht/kg. The advantage of this process is lower cost production than the FT synthesis process and hydrocracking.