PRODUCTION OF RENEWABLE HYDROCARBONS FROM THERMAL AND CATALYTIC PYROLYSIS OF BEEF TALLOW USING MESOPOROUS CATALYST OF Co, Ni AND Mo.
Beef Tallow; MCM-41; Pyrolysis; Biohydrocarbons; Kinetic Study
The need for studies on new sources of energy has grown significantly, considering that the use of fossil fuels substantially contributes to the worsening of issues such as acid rain, greenhouse effect, and consequently, global warming. Furthermore, there are also impacts on society, as these changes will ultimately interfere with humanity's survival and sustainability. In view of this problem, this doctoral thesis conducted a study on the efficiency of mesoporous catalysts of the MCM-41 type with incorporated metals such as cobalt, nickel, and molybdenum in the production of renewable hydrocarbons from beef tallow. The raw material was characterized physicochemically through analyses of acidity index, free fatty acids, saponification, peroxides, and refractive index. The synthesized catalysts had their structural characteristics analyzed via X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive Spectroscopy (EDS), confirming the formation and preservation of porous structures after the impregnation of metals. The activation energy was determined according to the isoconvective methods proposed by Ozawa-Flinn-Wall (OFW) and Kissinger Akahira Sunose (KAS), based on thermogravimetric analysis of bovine tallow and mixtures of bovine tallow with the catalysts, with heating rates (β) of 10, 20, and 30 °C/min, and conversion rates (α) of 5, 10, 20, 30, 40, 50, 60, 70, 80, and 90%. The catalysts produced in this study, according to both methods, proved effective in reducing the activation energy (Ea) in the thermocatalytic degradation reaction of bovine tallow, with Mo/MCM-41 standing out, showing a reduction of approximately 24% in the Ea of the raw material. Pyrolysis yielded a high percentage of renewable hydrocarbons, with 31.76% from thermal pyrolysis. This percentage increased in catalytic pyrolysis, with MCM-41 reaching 32.71%, Ni/MCM-41 76.18%, Mo/MCM-41 43.72%, Co/MCM-41 57.86%, NiMo/MCM-41 63.55%, CoMo/MCM-41 74.60%, and NiCo/MCM-41 84.99%. The production of hydrocarbons from thermal pyrolysis generated 46.03% in the bio-kerosene range, 39.33% in the green diesel range, and 14.64% of hydrocarbons with chain lengths above C24. On the other hand, thermocatalytic pyrolysis produced a higher amount of compounds in the green diesel range, with Ni/MCM-41 being the catalyst with the highest production of this biohydrocarbon, generating 27.24% of hydrocarbons in the bio-kerosene range, 70.19% in the green diesel range, and 2.57% with chain lengths above C24.