Biodiesel synthesis reaction routes from palm oil using plasma electro-catalysis process over Dielectric-Barrier Discharge (DBD) plasma reactor were studied. The study was focused on finding possible reaction mechanism route during plasma electro-catalysis process. The prediction was performed based on the changes of Gas Chromatography Mass Spectrometer (GC-MS) and Fourier Transform Infra Red (FT-IR) analyses to the biodiesel products with respect to time length of plasma treatment. It was found that main reaction mechanism occurred in the plasma electro-catalysis system was non-thermal pyrolysis rather than transesterification. The main reactions within the plasma treatment were due to collision between high energetic electrons (supplied from high voltage power supply through high voltage electrode) and the reaction mixtures. The high energetic electrons affected the electrons pair of covalent bonding to be excited or dissociated even ionized at higher energy. Therefore, this plasma electro-catalysis system was promising for biodiesel synthesis from vegetable oils due to only very short time reaction was needed, even no need a catalyst, no soap formation, and no glycerol by-product. This system could produce fatty acid methyl ester yield of 75.65% at 120 seconds and other possible chemicals, such as alkynes, alkanes, esters, carboxylic acid, and aldehydes. However, during the plasma process, the reaction mechanisms were still difficult to be controlled due the action of available high energetic electrons. The advanced studies on how to control the reaction mechanism selectively in the plasma electro-catalysis will be published elsewhere.

Catalyst waste from the residue fluid catalytic cracking (RFCC) plant process can still be utilized to catalyze the catalytic cracking of palm oil to fuels. However, we should regenerate the active sites of the catalyst waste. This paper focuses on enhancement of Brønsted and Lewis acid sites on the spent RFCC catalyst waste through various acid treatments in order to regenerate its catalyst active sites. In order to regenerate the Brønsted and the Lewis acid sites as active sites in the palm oil catalytic cracking, the spent RFCC catalyst was treated by citric acid, sulfuric acid, and mixture of both acids. The catalysts were characterized by X-ray fluorescence, X-ray diffraction, Brunauer–Emmett–Teller-Barrett–Joyner–Halenda, and pyridine-FTIR analysis. The modified catalyst performance was tested over a fixed bed reactor for the catalytic cracking process of palm oil to liquid fuels. It was found that the acid treatment on the spent RFCC catalyst can increase surface area, pore volume, and Brønsted to Lewis acid site ratio of catalysts. The Brønsted acid sites of the spent RFCC catalyst strongly increase by the treatment using sulfuric acid, which is because of the proton transfer from acid to catalyst and because of the formation of sulfate groups (HOSO3−) in the catalysts. It was found that the Brønsted acid site leads to the formation of long-chain hydrocarbon, while the Lewis acid site pronounces the formation of short-chain hydrocarbon and coke. Moreover, the total acidity and the Lewis acid site amount on the catalyst have roles in the formation of hydrocarbon fraction in the liquid product.

Biodiesel is an alternative biofuel that can replace diesel oil without requiring modifications to the engine and advantageously produces cleaner emissions. Biodiesel can be produced through transesterification process between oil or fat and alcohol to form esters and glycerol. The transesterification can be carried out with or without a catalyst. The catalyzed production of biodiesel can be performed by using homogeneous, heterogeneous and enzyme. Meanwhile, non-catalytic transesterification with supercritical alcohol provides a new way of producing biodiesel. Microwave and ultrasound assisted transesterification significantly can reduce reaction time as well as improve product yields. Another process, a plasma technology is promising for biodiesel synthesis from vegetable oils due to very short reaction time, no soap formation and no glycerol as a by-product. This paper reviews briefly the technologies on transesterification reaction for biodiesel production using homogeneous, heterogeneous, and enzyme catalysts, as well as advanced methods (supercritical, microwave, ultrasonic, and plasma technology). Advantages and disadvantages of each method were described comprehensively. Copyright © 2016 BCREC GROUP. All rights reserved <br /> <em>Received: 17th May 2016; Revised: 20th September 2016; Accepted: 20th September 2016</em> <br /> <strong>How to Cite:</strong> Buchori, L., Istadi, I., Purwanto, P. (2016). Advanced Chemical Reactor Technologies for Biodiesel Production from Vegetable Oils - A Review. <em>Bulletin of Chemical Reaction Engineering & Catalysis</em>, 11 (3): 406-430 (doi:10.9767/bcrec.11.3.490.406-430) <br /> <strong>Permalink/DOI:</strong> <a href="http://doi.org/10.9767/bcrec.11.3.490.406-430" /> http://doi.org/10.9767/bcrec.11.3.490.406-430</a>

Biofuels can be produced through a conventional catalytic cracking system and/or a hybrid catalyticplasma cracking system. This paper was focused on studying effect of Na + ion exchange to HY-Zeolite catalyst on catalyst performance to convert palm oil into biofuels over a conventional continuous fixed bed catalytic cracking reactor and comparing the catalytic cracking performance when carried out in a continuous hybrid catalytic-plasma reactor. The catalysts were characterized by X-ray Diffraction (XRD) and Bruneuer-Emmet-Teller (BET) surface area methods. The biofuels product were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) to determine the hydrocarbons composition of biofuels product. From the results, ion exchange process of Na + into HY-Zeolite catalyst decreases the catalyst activity due to decreasing the number of active sites caused by blocking of Na + ion. The selectivity to gasoline ranges achieved 34.25% with 99.11% total conversion when using HY catalyst over conventional continuous fixed bed reactor system. Unfortunately, the selectivity to gasoline ranges decreased to 13.96% and the total conversion decrease slightly to 98.06% when using NaY-Zeolite catalyst. As comparison when the cracking reaction was carried out in a hybrid catalytic-plasma reactor using a spent residual catalytic cracking (RCC) catalyst, the high energetics electron from plasma can improve the reactor performance, where the conversion and yield were increased and the selectivity to lower ranges of hydrocarbons was increased. However, the last results were potential to be intensively studied with respect to relation between reactor temperature and plasma-assisted catalytic reactor parameters.

Active solid acid catalysts of sulphated zinc oxide (SO 4 2--ZnO and SO 4 2-/ZnO) were prepared and characterized. The solid acid catalysts were investigated for their performance on transesterification of soybean oil with methanol to produce biodiesel. The SO 4 2--ZnO and SO 4 2-/ZnO catalysts were prepared by coprecipitation and impregnation respectively to compare their performance for biodiesel production. The catalysts were characterized by X-ray Diffraction (XRD) and Fourier Transform Infra Red (FT-IR), while the fatty acid methyl ester (FAME) component in biodiesel product was identified by Gas Chromatography -Mass Spectrometer (GC-MS) and FT-IR. The SO 4 2--ZnO catalyst, prepared by coprecipitation, showed better performance for the transesterification process than the SO 4 2-/ZnO catalyst, prepared by wet impregnation. The trend of performance of both catalyst was due to effect of sulfonate incorporation into the zinc oxide structure to form active acid sites. From the catalyst testing on transesterification of soybean oil with methanol at mild conditions (temperature of 65 o C, methanol to oil mole ratio of 6, and 4 wt% of catalyst loading), the SO 4 2--ZnO catalyst exhibited promising FAME yield of 80.19% at 4 h reaction time. Therefore, the SO 4 2--ZnO catalyst showed potential as a catalyst for transesterification of soybean oil to produce biodiesel.

The increase in energy demand led to the challenging of alternative fuel development. Biofuels from palm oil through catalytic cracking appear as a promising alternative fuel. In this study, biofuel was produced from palm oil through catalytic cracking using the modified HY zeolite catalysts. The Ni and Co metals were impregnated on the HY catalyst through the wet-impregnation method. The catalysts were characterized using X-ray fluorescence, X-ray diffraction, Brunauer–Emmett–Teller (BET), Pyridine-probed Fourier-transform infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM) methods. The biofuels product obtained was analyzed using a gas chromatography-mass spectrometry (GC-MS) method to determine its composition. The metal impregnation on the HY catalyst could modify the acid site composition (Lewis and Brønsted acid sites), which had significant roles in the palm oil cracking to biofuels. Ni impregnation on HY zeolite led to the high cracking activity, while the Co impregnation led to the high deoxygenation activity. Interestingly, the co-impregnation of Ni and Co on HY catalyst could increase the catalyst activity in cracking and deoxygenation reactions. The yield of biofuels could be increased from 37.32% to 40.00% by using the modified HY catalyst. Furthermore, the selectivity of gasoline could be achieved up to 11.79%. The Ni and Co metals impregnation on HY zeolite has a promising result on both the cracking and deoxygenation process of palm oil to biofuels due to the role of each metal. This finding is valuable for further catalyst development, especially on bifunctional catalyst development for palm oil conversion to biofuels.

This paper was purposed for testing reusability and stability of calcium oxide-based catalyst (K2O/CaO-ZnO) over transesterification reaction of soybean oil with methanol to produce biodiesel. The K2O/CaO-ZnO catalyst was synthesized by co-precipitation method of calcium and zinc nitrates followed by impregnation of potassium nitrate. The fresh and used catalysts were tested after regeneration. The catalysts were characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and BET Surface Area in order to compare the catalyst structure between the fresh and used catalysts. The catalyst testing in transesterification proses was carried out at following operating conditions, i.e. catalyst weight of 6 wt.%, oil to methanol mole ratio of 1:15, and temperature of 60 oC. In addition, metal oxide leaching of K2O/CaO-ZnO catalyst during reaction was also tested. From the results, the catalysts exhibited high catalytic activity (80% fatty acid methyl ester (FAME) yield after three-cycles of usage) and acceptable reusability after regeneration. The catalyst also showed acceptable stability of catalytic activity, even after three-cycles of usage.

Plasma-assisted catalytic cracking is an attractive method for producing biofuels from vegetable oil. This paper studied the effect of reactor temperature on the performance of plasma-assisted catalytic cracking of palm oil into biofuels. The cracking process was conducted in a Dielectric Barrier Discharge (DBD)-type plasma reactor with the presence of spent RFCC catalyst. The reactor temperature was varied at 400, 450, and 500 ºC. The liquid fuel product was analyzed using a gas chromatography-mass spectrometry (GC-MS) to determine the compositions. Result showed that the presenceof plasma and catalytic role can enhance the reactor performance so that the selectivity of the short-chain hydrocarbon produced increases. The selectivity of gasoline, kerosene, and diesel range fuels over the plasma-catalytic reactor were 16.43%, 52.74% and 21.25%, respectively, while the selectivity of gasoline, kerosene and diesel range fuels over a conventional fixed bed reactor was 12.07%, 39.07%, and 45.11%, respectively. The increasing reactor temperature led to enhanced catalytic role of cracking reaction,particularly directing the reaction to the shorter hydrocarbon range. The reactor temperature dependence on the liquid product components distribution over the plasma-catalytic reactor was also studied. The aromatic and oxygenated compounds increased with the reactor temperature.©2020. CBIORE-IJRED. All rights reserved