Biodiesel production from soybean oil using modified calcium loaded on rice husk activated carbon as a low-cost basic catalyst

Activated carbon was obtained by hydrothermal process using rice husk as raw materials. The study in our lab had been developed to produce high-quality biodiesel from soybean oil with the activated carbon-base catalyst. The polyethylene glycol (PEG 400) modified calcium loaded on the rice husk activated carbon (CaO/AC) catalyst was prepared via the dipping method and then was used as a heterogeneous solid-base catalyst to produce biodiesel. The effects of CaO/AC ratio and calcination time on catalytic performance were researched according to the yield of biodiesel, and the optimum reaction conditions for biodiesel from soybean oil via PEG 400–modified CaO/AC catalyst were evaluated. The results showed that the yield of fatty acid methyl ester (FAME) achieved 93.01% at the reaction temperature of 342 K, methanol/oil molar ratio of 10:1, and reaction time of 6 h. All in all, modified CaO/AC catalyst showed very high activity for transesterification of soybean oil and had catalytic repeated availability.     

Production of fatty acid methyl esters over a limestone-derived heterogeneous catalyst in a fixed-bed reactor

Production of fatty acid methyl esters (FAME) via the transesterification of different vegetable oils and methanol with a limestone-derived heterogeneous catalyst was investigated in a fixed-bed reactor at 65 °C and ambient pressure. This heterogeneous catalyst, as a 1 or 2 mm cross-sectional diameter extrudate, was prepared via a wet mixing of thermally treated limestone with Mg and Al compounds as binders and with or without hydroxyethyl cellulose (HEC) as a plasticizer, followed by calcination at 800 °C. The physicochemical properties of the prepared catalysts were characterized by various techniques. Palm kernel oil, palm oil, palm olein oil and waste cooking oil could be used as the feedstocks but the FFA and water content must be limited. The extrudate catalyst prepared with the HEC addition exhibited an enhanced formation of FAME due to an increased porosity and basicity of the catalyst. The FAME yield was increased with the methanol/oil molar ratio. The effect of addition of methyl esters as co-solvents on the FAME production was investigated. The structural and compositional change of the catalysts spent in different reaction conditions indicated that deactivation was mainly due to a deposition of glycerol and FFA (if present). The FAME yield of 94.1 wt.% was stably achieved over 1500 min by using the present fixed-bed system.     

Process optimization for methyl ester production from waste cooking oil using activated carbon supported potassium fluoride

This paper presents the transesterification of waste cooking palm oil (WCO) using activated carbon supported potassium fluoride catalyst. A central composite rotatable design was used to optimize the effect of molar ratio of methanol to oil, reaction period, catalyst loading and reaction temperature on the transesterification process. The reactor was pressurized up to 10 bar using nitrogen gas. All the variables were found to affect significantly the methyl ester yield where the most effective factors being the amount of catalyst and reaction temperature, followed by methanol to oil ratio. A quadratic polynomial equation was obtained for methyl ester yield by multiple regression analysis using response surface methodology (RSM). The optimum condition for transesterification of WCO to methyl ester was obtained at 3 wt.% amount of catalyst, 175 °C temperature, 8.85 methanol to oil molar ratio and 1 h reaction time. At the optimum condition, the predicted methyl ester yield was 83.00 wt.%. The experimental value was well within the estimated value of the model. The catalyst showed good performance with a high yield of methyl ester and the separation of the catalyst from the liquid mixture is easy.     

Long term activity of modified ZnO nanoparticles for transesterification

Biodiesel can be produced by the transesterification of natural oils with methanol using modified ZnO nanoparticles as catalyst. Crude algae oil, corn oil from DDGs, crude palm oil, crude soybean oil, crude coconut oil, waste cooking oil, food-grade soybean oil and food-grade soybean oil with 3% water and 5% FFA addition were converted into FAME within 3 h using this new catalyst. The ZnO nanoparticles were reused 17 times without any activity loss in a batch stirred reactor and the average yield of FAME was around 93.7%. ZnO nanoparticles were used continuously for 70 days in a fix bed continuous reactor and the average yield of FAME was around 92.3%. XRD, ICP, TEM and HRTEM were used to characterize the long term used catalyst structure. Results show that this catalyst is a mixture of wurtzite ZnO nanoparticles and some amorphous materials and that the used catalysts have similar crystal structure to fresh catalyst. ICP results show that this catalyst does not dissolve in biodiesel, methanol, oil and glycerine-methanol solutions. It has a stable crystal structure under the reaction conditions. The high catalytic activity, long catalyst life and low leaching properties demonstrate these modified ZnO nanoparticles have potential in a commercial biodiesel production process.     

Esterification of sludge palm oil using trifluoromethanesulfonic acid for preparation of biodiesel fuel

Trifluoromethanesulfonic acid (TFMSA) was used to reduce the high free fatty acids (FFA) content in sludge palm oil (SPO). The FFA content of SPO was converted to fatty acid methyl ester (FAME) via esterification reaction. The treated sludge palm oil was used as a raw material for biodiesel production by transesterification process. Several working parameters were optimized, such as dosage of catalyst, molar ratio, reaction temperature and time. Less than 2% of the FFA content was the targeted value. The results showed that the FFA content of SPO was reduced from 16% to less than 2% using the optimum conditions. The yield of the final product after the alkaline transesterification was 84% with 0.07% FFA and the ester content was 96.7%. All other properties met the international standard specifications for biodiesel quality such as EN 14214 and ASTM D6751.     

Biodiesel production using alumina-supported calcium oxide: An optimization study

This study consists of the optimization of the methyl ester yields produced via transesterification of palm oil using CaO/Al₂O₃ solid base catalyst. Response Surface Methodology (RSM) in combination with Central Composite Design (CCD) was used to optimize the operating parameters. Alcohol/oil molar ratio, catalyst content in the reaction medium and reaction temperature were chosen as the variables and the response selected was the amount of methyl ester yields. All the reactions were performed in a batch laboratory scale reactor for 5 h; the optimum reaction conditions obtained were approximately alcohol/oil molar ratio of 12:1, catalyst content of 6 wt.% and reaction temperature of 65 °C. The results from ICP-MS exhibited insignificant leaching of the CaO active species into the reaction medium and the reusability of the catalyst was successfully tested in two subsequent cycles. Under certain reaction conditions the glycerol obtained was almost colorless.     

酯化-酯交换两步法制备生物柴油的动力学

以潲水油（WCO）为原料,探讨了酯化-酯交换两步法制备生物柴油的反应动力学。以活性炭负载硫酸铁［Fe₂(SO₄)₃/AC］为负载型催化剂,通过测定不同反应温度、不同甲醇/脂肪酸（FFA）摩尔比条件下WCO中游离脂肪酸的转化率,以此确定酯化反应的动力学控制步骤及动力学方程中的待定参数,从而建立了在实验温度范围内酯化反应的动力学方程,并根据碱催化酯交换反应机理,在简化的动力学模型基础上,推导出了WCO中甘油三酯（TG）与甲醇发生酯交换反应的宏观动力学方程。结果表明,酯化反应和酯交换反应的动力学方程在实验条件范围内都能较好地描述各自的反应过程。     

Tri-potassium phosphate as a solid catalyst for biodiesel production from waste cooking oil

Transesterification of waste cooking oil with methanol, using tri-potassium phosphate as a solid catalyst, was investigated. Tri-potassium phosphate shows high catalytic properties for the transesterification reaction, compared to CaO and tri-sodium phosphate. Transesterification of waste cooking oil required approximately two times more solid catalyst than transesterification of sunflower oil. The fatty acid methyl ester (FAME) yield reached 97.3% when the transesterification was performed with a catalyst concentration of 4 wt.% at 60 °C for 120 min. After regeneration of the used catalyst with aqueous KOH solution, the FAME yield recovered to 88%. Addition of a co-solvent changed the reaction state from three-phase to two-phase, but reduced the FAME yield, contrary to the results with homogeneous catalysts. The catalyst particles were easily agglomerated by the glycerol drops derived from the homogeneous liquid in the presence of co-solvents, reducing the catalytic activity.     

Transesterification of karanja (Pongamia pinnata) oil by solid basic catalysts

The transesterification of karanja oil with methanol was carried out using solid basic catalysts. Alkali metal‐impregnated calcium oxide catalysts, due to their strong basicity, catalyze the transesterification of triacylglycerols. The alkali metal (Li, Na, K)‐doped calcium oxide catalysts were prepared and used for the transesterification of karanja oil containing 0.48–5.75% of free fatty acids (FFA). The reaction conditions, such as catalyst concentration, reaction temperature and molar ratio of methanol/oil, were optimized with the solid basic Li/CaO catalyst. This catalyst, at a concentration of 2 wt‐%, resulted in 94.9 wt‐% of methyl esters in 8 h at a reaction temperature of 65 °C and a 12 : 1 molar ratio of methanol to oil, during methanolysis of karanja oil having 1.45% FFA. The yield of methyl esters decreased from 94.9 to 90.3 wt‐% when the FFA content of karanja oil was increased from 0.48 to 5.75%. The performance of this catalyst was not significantly affected in the presence of a high FFA content up to 5.75%. The catalytic activities of Na/CaO and K/CaO were also studied at the optimized reaction conditions. In these two cases, the reaction initially proceeds slowly, however, leading to similar yields as in the case of Li/CaO after 8 h of reaction time. The purified karanja methyl esters have an acid value of 0.36 mg KOH/g and an ester content of 98.6 wt‐%, which satisfy the American as well as the European specifications for biodiesel in terms of acid value and ester content.     

Oil transesterification over calcium oxides modified with lanthanum

Investigations were conducted on a series of calcium and lanthanum oxides catalyst for biodiesel production. Mixed oxides catalyst showed a superior transesterification activity over pure calcium or pure lanthanum oxide catalysts. The catalyst activity was correlated with surface basicity and specific surface areas. The effects of water and free fatty acids (FFA) levels in oil feedstock, water and CO₂ in air, mass ratio of catalyst, molar ratio of oil to methanol, and reaction temperature on fatty acid methyl ester (FAME) yield were investigated. Under optimal conditions, FAME yields reached 94.3% within 60 min at 58 °C. Mixed CaO-La₂O₃ catalyst showed a high tolerance to water and FFA, and could be used for converting pure or diluted unrefined/waste oils to biodiesel.     

Calcium oxide as a solid base catalyst for transesterification of soybean oil and its application to biodiesel production

In order to study solid base catalyst for biodiesel production with environmental benignity, transesterification of edible soybean oil with refluxing methanol was carried out in the presence of calcium oxide (CaO), -hydroxide (Ca(OH)₂), or -carbonate (CaCO₃). At 1 h of reaction time, yield of FAME was 93% for CaO, 12% for Ca(OH)₂, and 0% for CaCO₃. Under the same reacting condition, sodium hydroxide with the homogeneous catalysis brought about the complete conversion into FAME. Also, CaO was used for the further tests transesterifying waste cooking oil (WCO) with acid value of 5.1 mg-KOH/g. The yield of FAME was above 99% at 2 h of reaction time, but a portion of catalyst changed into calcium soap by reacting with free fatty acids included in WCO at initial stage of the transesterification. Owing to the neutralizing reaction of the catalyst, concentration of calcium in FAME increased from 187 ppm to 3065 ppm. By processing WCO at reflux of methanol in the presence of cation-exchange resin, only the free fatty acids could be converted into FAME. The transesterification of the processed WCO with acid value of 0.3 mg-KOH/g resulted in the production of FAME including calcium of 565 ppm.     

Potassium hydroxide catalyst supported on palm shell activated carbon for transesterification of palm oil

In this study, potassium hydroxide catalyst supported on palm shell activated carbon was developed for transesterification of palm oil. The Central Composite Design (CCD) of the Response Surface Methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst loading and methanol to oil molar ratio on the production of biodiesel using activated carbon supported catalyst. The highest yield was obtained at 64.1 °C reaction temperature, 30.3 wt.% catalyst loading and 24:1 methanol to oil molar ratio. The physical and chemical properties of the produced biodiesel met the standard specifications. This study proves that activated carbon supported potassium hydroxide is an effective catalyst for transesterification of palm oil.     

微量酸催化麻疯树籽油制备生物柴油(英文)

Biodiesel produced from crude Jatropha curcas L.oil with trace sulfuric acid catalyst(0.02%-0.08% oil) was investigated at 135-184 ℃.Both esterification and transesterification can be well carried out simultane-ously.Factors affecting the process were investigated,which included the reaction temperature,reaction time,the molar ratio of alcohol to oil,catalyst amount,water content,free fatty acid(FFA) and fatty acid methyl ester(FAME) content.Under the conditions at 165 ℃,0.06%(by mass) H2SO4 of the oil mass,1.6 MPa and 20:1 methanol/oil ratio,the yield of glycerol reached 84.8% in 2 hours.FFA and FAME showed positive effect on the transesterification in certain extent.The water mass content below 1.0% did not show a noticeable effect on trans-esterification.Reaction kinetics in the range of 155 ℃ to 175 ℃ was also measured.     

Biodiesel Production Over Arenesulfonic Acid-Modified Mesostructured Catalysts: Optimization of Reaction Parameters Using Response Surface Methodology

The catalytic activity of different heterogeneous sulfonic acid-modified catalysts has been assayed in the simultaneous esterification of FFA and transesterification of triglycerides of crude palm oil (FFA content of 5.6 wt%) with methanol, demonstrating the applicability of this kind of acid solids to the one-step production of biodiesel from FFA-containing vegetable oils. The yield towards fatty acid methyl esters (FAMEs) obtained over these acid materials is enhanced when increasing the acid strength of the catalytic site. Likewise, the use of mesostructured supports has been shown as a factor improving the catalytic performance as compared with macroporous sulfonic acid-based resins, likely due to an enhancement of the mass transfer rates of large molecules, such as triglycerides, within the catalyst structure. Thus, the combination of the open mesoporous structure of a SBA-15 silica support with relatively strong arenesulfonic acid sites leads to a material able to yield high conversion of triglycerides and free fatty acids. Furthermore, a study on the transesterification reaction of crude palm oil with methanol through a surface response analysis has provided as optimal conditions the following: temperature 160 °C, catalyst loading 5.1 wt% referred to the amount of palm oil, and methanol to oil molar ratio 30. Under these conditions, almost 90% of the starting oil is converted to FAME after reacting for just 2 h of reaction. Likewise, surface response analysis has evidenced a strong interaction between temperature and methanol to oil ratio.     

Transesterification of waste cooking palm oil by MnZr with supported alumina as a potential heterogeneous catalyst

The transesterification of waste cooking palm oil (WCPO) with methanol into fatty acid methyl esters (FAMEs) was investigated using solid acidic mixed oxide catalysts Mn_3.5xZr_0.5yAl_xO₃ prepared via coprecipitation. The effects of reaction temperature, time, molar methanol-to-oil ratio, and catalyst loading were investigated. The stability of the catalytic activity was examined via leaching and reusability tests through five consecutive batch runs. The catalyst achieved a FAME content of more than 93%, and the optimal reaction conditions are as follows: reaction temperature of 150 °C, reaction time of 5 h, molar methanol-to-WCPO ratio of 14:1, and catalyst loading of 2.5 wt.%.     

BIODIESEL PRODUCTION FROM PALM OIL VIA HETEROGENEOUS TRANSESTERIFICATION: OPTIMIZATION STUDY

Fatty acid methyl ester (FAME) prepared by transesterification process using a heterogeneous catalyst has received a lot of interest lately as it could overcome the limitations of the current commercial homogeneous catalytic process. Apart from that, palm oil, being the cheapest edible oil in the world, will always remain the most economical source of FAME. Therefore, in this study, the use of sulfated zirconia alumina as a heterogeneous catalyst to catalyze the transesterification of palm oil with methanol to FAME was carried out using design of experiment (DOE), specifically response surface methodology (RSM) based on four-variable central composite design (CCD) with α = 2. The transesterification process variables are reaction temperature (60–180°C), reaction period (1–5 h), methanol-to-oil ratio (4–12 mol mol^?1), and amount of catalyst (2–10 wt.%). In this study involving many multiple process variables, the design of experiment approach was found to be superior to the conventional one-variable-at-one-time approach. Interactions between variables were found to have significant effect on the yield of FAME. At the conditions of 3 h of reaction period, 127°C reaction temperature, methanol-to-palm oil ratio of 8, and 6 wt.% of catalyst, an optimum FAME yield of 83.3% can be obtained, indicating that sulfated zirconia alumina has potential as a heterogeneous catalyst for the production of FAME from palm oil.     

Transesterification kinetics of palm olein oil using supercritical methanol

Continuous transesterification of palm olein oil using supercritical methanol was investigated in the absence of a catalyst. The variables studied were reaction temperature (270–350 °C), pressure (20–40 MPa), and residence time (5–25 min), with a methanol-to-oil molar ratio of 40. Preheating at 245 °C was used to form a homogeneous phase in the absence of thermal decomposition of palm olein oil. The activation energies and reaction activation volumes of the fatty acid methyl ester (FAME), and those of the individual components (C16:0, C18:0, C18:1, and C18:2 methyl esters), were calculated. The entropies of activation (ΔS^‡) of the transesterification reactions were also obtained. As the transesterification of vegetable oil in supercritical methanol included a strongly negative (−175 J/mol K) entropy of activation, transesterification required harsh conditions.     

Transesterification of palm oil on KyMg1 − xZn1 + xO3 catalyst: Effect of Mg-Zn interaction

The Mg-Zn interaction effect of K_yMg_1 − xZn_1 + xO₃ heterogeneous type catalyst and its performance on transesterification of palm oil have been studied using the response surface methodology and the factorial design of experiments. The catalyst was synthesized using the co-precipitation method and the activity was assessed by transesterification of palm oil into fatty acid methyl esters. The ratio of the Mg/Zn metal interaction, temperature and time of calcination were found to have positive influence on the conversion of palm oil to fatty acid methyl ester (FAME) with the effect of metal to metal ratio and temperature of calcination being more significant. The catalytic activity was found to decrease at higher calcination temperature and the catalyst type K₂Mg_0.34Zn_1.66O₃ with Mg/Zn ratio of 4.81 gave FAME content of 73% at a catalyst loading of 1.404 wt.% of oil with molar ratio of methanol to oil being 6:1 at temperature of 150 °C in 6 h. A regression model was obtained to predict conversions to methyl esters as a function of metal interaction ratio, temperature of calcination and time. The observed activity of the synthesized catalyst was due to its synergetic structure and composition.     

Heterogeneous transesterification processes by using CaO supported on zinc oxide as basic catalysts

Zinc oxide, obtained by thermal decomposition of zinc oxalate, has been impregnated with different amounts of calcium oxide, and used as solid catalyst for transesterification processes. Catalysts have been characterized by chemical analysis, XRD, XPS, FT-IR, SEM, N₂ adsorption–desorption at 77 K and CO₂-TPD. The catalytic behaviour has been evaluated by choosing two transesterification processes: a simple model such as the reaction between ethyl butyrate and methanol and the production of biodiesel from sunflower oil and methanol. Calcium oxide is stabilized by filling the mesoporous network of ZnO, as reveal the corresponding pore size distributions, thus avoiding the lixiviation of the active phase in the reaction medium. These supported CaO catalysts, thermally activated at 1073 K, can give rise to FAME (fatty acid methyl esters) yield higher than 90%, after 2 h of reaction, when a methanol:oil molar ratio of 12 and 1.3 wt% of the catalyst with a 16 wt% CaO were employed.     

Metakaolinite as a catalyst for biodiesel production from waste cooking oil

The use of metakaolinite as a catalyst in the transesterification reaction of waste cooking oil with methanol to obtain fatty acid methyl esters (biodiesel) was studied. Kaolinite was thermally activated by dehydroxylation to obtain the metakaolinite phase. Metakaolinite samples were characterized using X-ray diffraction, N₂ adsorption-desorption, simultaneous thermo-gravimetric analyse/differential scanning calorimetry (TGA/DSC) experiments on the thermal decomposition of kaolinite and Fourier-transform infrared spectrometer (FTIR) analysis. Parameters related to the transesterification reaction, including temperature, time, the amount of catalyst and the molar ratio of waste cooking oil to methanol, were also investigated. The transesterification reaction produced biodiesel in a maximum yield of 95% under the following conditions: metakaolinite, 5 wt-% (relative to oil); molar ratio of oil to methanol, 1∶23; reaction temperature, 160°C; reaction time, 4 h. After eight consecutive reaction cycles, the metakaolinite can be recovered and reused after being washed and dried. The biodiesel thus obtained exhibited a viscosity of 5.4?mm²?s^–1 and a density of 900.1 kg?m^–3. The results showed that metakaolinite is a prominent, inexpensive, reusable and thermally stable catalyst for the transesterification of waste cooking oil.