One of the most important aspects in the catalytic cracking of bio-oil is understanding the kinetics of the process.The aim of this paper was to study the kinetics of bio-oil cracking with a silica-alumina catalyst using a continuous fixed-bed reactor. The reaction was studied over the temperature range of 450 to 600 °C with a catalyst bed length of 1 to 4 cm. Three models, Models 1, 2, and 3, were proposed to represent the catalytic cracking kinetics of bio-oil. Model 1 was based on the cracking of bio-oil into the products, while Models 2 and 3 were based on the threeand four-lump models, respectively. The results showed that the rate constants of the catalytic cracking of bio-oil increased with an increasing temperature. The reaction rate constants of the catalytic cracking of biooil using Model 1 ranged from 0.221 to 0.416 cm 3 /g cat·min with an activation energy of 22.3 kJ/mol. It was found that the reaction rate constants from Model 2 can be employed to describe the cracking phenomenon of bio-oil, liquid hydrocarbons, and gas and coke, whereas Model 3 can illustrate the kinetics of bio-oil, kerosene, gasoline, and gas and coke cracking.

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Abstract. Biodiesel production from microalgae is one of the solution of the future energy problem, but its production cost is still high. One of the costly stages of this process is the lipid extraction process. It can be reduced by microalgae cell disruption. One of the mechanical method to cell disruption with the lowest energy requirement is hydrodynamic cavitation. This aim of this study is to evaluate the distribution coefficient and the mass transfer coefficient value of lipid extraction of Nannochloropsis sp. assisted by hydrodynamic cavitation and compare with conventional extraction. The hydrodynamic cavitation extraction was done at 34 C, 1 atm. The conventional extraction was done at 34 C, 1 atm with stirring speed 260 and 1000 rpm. The experimental result shows that the distribution coefficient dependent on the temperature with the values for 50, 44, 38 and 34 C were 0.502, 0.394, 0.349, and 0.314 respectively. And it was according to Van' Hoff equation with the values of H was 20.718 kJ/mol and S was 58.05 J/mol/K. The hydrodynamic cavitation extraction was faster than conventional. The mass transfer coefficient values for hydrodynamic cavitation, conventional 260 rpm and 1000 rpm were 7.373, 0.534 and 0.121 1/s respectively.

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Solid pollution has been an issue in mineral processing for decade. One of these pollutants is zircon sand mining waste (zircon tailing). Due to the concentration of rare earth minerals in zircon tailing and the increasing demand of REE in advanced technologies, studying zircon tailing as a potential source of REE had become an interest for us. Our experiments consisted of mineral characterization and an alkaline fusion process, followed by a leaching process. The characterization process was carried out to obtain actual information from zircon tailing samples. This process showed total rare earth elements (REEs) content of 58.62%, at 9%, 1%, 1.2%, 1.7%, and 1.5% for Y, Gd, Er, Dy, and Yb, respectively. A sieving process was carried out since it was known that most heavy rare earth elements (HREEs) content occurs at a larger size. The alkaline fusion process was applied with an intent to break the phosphate bonds present in the REE-carrying minerals (xenotime and monazite) and convert phosphate bonds to hydroxide bonds in rare earth metals. During the alkaline fusion process, as much as 75%, 66.45%, and 60% of the phosphate, silica, and zirconium, respectively, were reduced. The leaching process was carried out in a flatbottom three-neck flask. The optimum point of leaching experiments occurs at 0.5 M H2SO4, 60°C, and a solid-to-liquid (S/L) ratio of 10 g/100 mL. In these conditions, as much as 89%, 99%, 94%, 92%, and 90% of Y, Gd, Er, Dy, and Yb, respectively, were recovered as an HREEs2-(SO4)3 product solution.

Bagasse (Saccarum oficinarum L) is a waste of sugar mills that can be utilized for a variety of chemicals. The purposes of this study are to determine the percentage of compounds and physical properties of bio-oil, to determine the effect of variations of particle size and heating rate on the yields of bio-oil. Pyrolysis has been carried out in a reactor made of steel pipe type 5737 with dimension: diameter 7.62 em and a length of 3 7 cm.. The reactor was inserted into the furnace with a diameter of 15.24 em and a length of 40 em. One hundred and fifty grams of bagasse (Saccarum oficinarum L) has been inserted into the reactor without the presence of oxygen at atmospheric pressure. Pyrolysis has been carried out at the particle size of (-20+25) mesh, (-25+30) mesh, (-30+35) mesh, (- 35+40) mesh, and -40 mesh with electrical voltage of 100, 105, 115, and 120 volt. Produced of bio-oil has the following properties: brown color, pH of 2.96 to 3.03, viscosity of 1.3306 to 1.5101 cp, and density of 1.03 to 1.5 g/mL. The largest content of the compound is acetic acid (59, 72%). The highest yields percentage of the particle size is (40,32%) on (-20+25 mesh) with the highest yields percentage of electrical voltage is 38,82% on 105 volt.Keywords : Bagasse, acetic acid, bio-oil, pyrolysis, yields