Alkaline-catalyzed transesterification of Silurus triostegus Heckel fish oil: Optimization of transesterification parameters

The present work reports the production of biodiesel from Silurus triostegus Heckel fish oil (STFO) through alkaline-catalyzed transesterification by using potassium hydroxide (KOH) as an alkaline catalyst with methanol. Chemical and physical properties of the extracted oil were determined. It was found that STFO has a low acid value (1.90 mg KOH/g oil); hence no pre-treatment such as acid esterification is required to produce the biodiesel. The influence of the experimental parameters such as KOH concentration (0.25–1.0% w/w of oil), methanol to oil molar ratio (3:1, 6:1, 9:1 and 12:1), reaction temperature (32, 45 and 60 °C), reaction duration (30, 60, 90 and 120 min), type of the catalyst (potassium or sodium hydroxide) and step multiplicity (single- and two-step transesterification) on the yield of the biodiesel were investigated. The maximum biodiesel yield (96%) was obtained under the optimized parameters of the transesterification (KOH 0.50% w/w, 6:1 methanol to oil, at 32 °C for 60 min). The properties of the produced biodiesel were found to conform with the ASTM standard, indicating its suitability for internal combustion engines. Blending of the produced biodiesel with petro diesel with various volume percentages was investigated as well.     

Optimized alkali-catalyzed transesterification of wild mustard (Brassica juncea L.) seed oil

Biodiesel was developed from a non-edible oil source, i.e., wild mustard (Brassica juncea L) oil through optimized alkali-catalyzed transesterification with methanol using potassium hydroxide as a catalyst. Biodiesel yield of (95.54 % with 96.72 % w/w ester content) was obtained under optimal conditions of 0.75 % KOH w/w of oil, 6:1 methanol to oil molar ratio, 60°C temperature, and a duration of 45 min. Properties of wild mustard (Brassica juncea L) oil biodiesel were determined and found to be within the limits of ASTM D6751 specifications. As a result, wild mustard (Brassica juncea L), as an agricultural crop, might be a reasonable feedstock for biodiesel production.     

Performance evaluation of artificial neural network coupled with generic algorithm and response surface methodology in modeling and optimization of biodiesel production process parameters from shea tree (Vitellaria paradoxa) nut butter

This work investigated the potential of shea butter oil (SBO) as feedstock for synthesis of biodiesel. Due to high free fatty acid (FFA) of SBO used, response surface methodology (RSM) was employed to model and optimize the pretreatment step while its conversion to biodiesel was modeled and optimized using RSM and artificial neural network (ANN). The acid value of the SBO was reduced to 1.19 mg KOH/g with oil/methanol molar ratio of 3.3, H₂SO₄ of 0.15 v/v, time of 60 min and temperature of 45 °C. Optimum values predicted for the transesterification reaction by RSM were temperature of 90 °C, KOH of 0.6 w/v, oil/methanol molar ratio of 3.5, and time of 30 min with actual shea butter oil biodiesel (SBOB) yield of 99.65% (w/w). ANN combined with generic algorithm gave the optimal condition as temperature of 82 °C, KOH of 0.40 w/v, oil/methanol molar ratio of 2.62 and time of 30 min with actual SBOB yield of 99.94% (w/w). Coefficient of determination (R²) and absolute average deviation (AAD) of the models were 0.9923, 0.83% (RSM) and 0.9991, 0.15% (ANN), which demonstrated that ANN model was more efficient than RSM model. Properties of SBOB produced were within biodiesel standard specifications.     

A comparative study of vegetable oil methyl esters (biodiesels)

In the present study, rubber seed oil, coconut oil and palm kernel oil, which are locally available especially in Kerala (India), are chosen and their transesterification processes have been investigated. The various process variables like temperature, catalyst concentration, amount of methanol and reaction time were optimized. Biodiesel from rubber seed oil (with high free fatty acid) was produced by employing two-step pretreatment process (acid esterification) to reduce acid value from 48 to 1.72 mg KOH/g with 0.40 and 0.35 v/v methanol-oil ratio and 1.0% v/v H₂SO₄ as catalyst at a temperature of 63(±2) °C with 1 h reaction time followed by transesterification using methanol-oil ratio of 0.30 v/v, 0.5 w/v KOH as alkaline catalyst at 55(±2) °C with 40 min reaction time to yield 98-99% biodiesel. Coconut oil and palm oil, being edible oils, transesterification with 0.25 v/v methanol-oil ratio, 0.50% w/v KOH as at 58(±2) °C, 20 min reaction time for coconut oil and 0.25% v/v methanol-oil ratio, 0.50% w/v KOH as alkaline catalyst at 60(±2) °C for palm kernel oil will convert them to 98-99% biodiesel. The brake thermal efficiency of palm oil biodiesel was higher with lower brake specific fuel consumption, but rubber seed oil biodiesel(ROB) showed less emission (CO and NO_x) compared to other biodiesels.     

Production and evaluation of biodiesel from mixed castor oil and waste chicken oil

Biodiesel was developed from an unconventional feedstock, i.e. an equivalent blend of castor bean and waste chicken oil through the alkaline-catalyzed transesterification with methanol. The process variables including the alkaline catalyst concentration, methanol to oil molar ratio, reaction temperature, reaction time, and the alkaline catalyst type were investigated. The highest yield of biodiesel (97.20 % ~ 96.98 % w/w ester content) was obtained under optimum conditions of 0.75 % w/w of oil, 8:1 methanol to oil molar ratio, 60°C temperature, and a duration of 30 min. Properties of the produced biodiesel satisfied those specified by the ASTM standards. The results thus indicated that the suggested blend oils are suitable feedstock for the production of biodiesel. The process was found to follow pseudo first-order kinetics, and the activation energy was found to be 8.85 KJ/mole.     

Biodiesel production from two stage esterification of simarouba glauca seed oil and its characterization

In this work, biodiesel was produced from simarouba glauca seed oil through a two-stage acid-alkali esterification process. Concentrated sulphuric acid and sodium hydroxide were used as catalysts for acid and alkaline catalyzed esterification process, respectively. The free fatty acid content of the oil was reduced from 3.5 to 0.2%. The major properties of oil and its biodiesel were studied. Upon two-stage esterification, kinematic viscosity was reduced from 45.75 to 3.1 cSt and the acid value was reduced from 6.9348 to 0.4 mg KOH/g. The measured physio-chemical properties are within the limits set by ASTM biodiesel standards.     

Biodiesel production from crude rice bran oil and properties as fuel

This research reported on the successfully production of biodiesel by transesterification of crude rice bran oil (RBO). The process included three-steps. Firstly, the acid value of RBO was reduced to below 1 mg KOH/g by two-steps pretreatment process in the presence of sulfuric acid catalyst. Secondly, the product prepared from the first process was carried out esterification with an alkaline catalyst. The influence of four variables on conversion efficiency to methyl ester, i.e., methanol/RBO molar ratio, catalyst amount, reaction temperature and reaction time, was studied at this stage. The content of methyl ester was analyzed by chromatographic analysis. Through orthogonal analysis of parameters in a four-factor and three-level test, the optimum reaction conditions for the transesterification were obtained: methanol/RBO molar ratio 6:1, usage amount of KOH 0.9% w/w, reaction temperature 60 °C and reaction time 60 min. In the third step, methyl ester prepared from the second processing step was refined to become biodiesel. Fuel properties of RBO biodiesel were studied and compared according to ASTM D6751-02 and DIN V51606 standards for biodiesel. Most fuel properties complied with the limits prescribed in the aforementioned standards. The consequent engine test showed a similar power output compared with regular diesel but consumption rate was slightly higher. Emission tests showed a marked decrease in CO, HC and PM, however, with a slight increase in NO_X.     

Production of biodiesel from food processing waste using response surface methodology

The optimum conditions for biodiesel production by the transesterification of waste oil form the pork grilling process in the food factory in Udon Thani, Thailand, using NaOH and KOH as catalysts, has been investigated. A Box–Behnken Design (BBD) followed by a Response Surface Methodology (RSM) with 30 runs was used to assess the significance of three factors: the methanol to oil molar ratio, the amount of NaOH and KOH used, and the reaction time required to achieve the optimum percent fatty acid methyl ester (%FAME). The measured %FAME following transesterification using NaOH as a catalyst was an optimum 95.6% with a methanol to oil molar ratio of 12.2:1, a NaOH percentage mass fraction of 0.49% and a reaction time of 63 min. Using KOH as a catalyst, the %FAME was an optimum 93.0% with a methanol to oil molar ratio of 12:1, a KOH percentage mass fraction of 0.61% and a reaction time of 72 min. The coefficient of determination (R²) for regression equations were 98.55% and 93.99%, respectively. The probability value (P<0.05) demonstrated a very good significance for the regression model. The physicochemical properties of the biodiesel obtained from the waste oil met the ASTM 6751 biodiesel standard, illustrating that waste oil from the pork grilling process can be used as a raw material for biodiesel production by transesterification.     

Biodiesel production from mahua (Madhuca indica) oil having high free fatty acids

A technique to produce biodiesel from mahua oil (Madhuca indica) having high free fatty acids (19% FFA) has been developed. The high FFA level of mahua oil was reduced to less than 1% by a two-step pretreatment process. Each step was carried out with 0.30–0.35 v/v methanol-to-oil ratio in the presence of 1% v/v H₂SO₄ as an acid catalyst in 1-hour reaction at 60°C. After the reaction, the mixture was allowed to settle for an hour and methanol–water mixture that separated at the top was removed. The second step product at the bottom was transesterified using 0.25 v/v methanol and 0.7% w/v KOH as alkaline catalyst to produce biodiesel. The fuel properties of mahua biodiesel were found to be comparable to those of diesel and conforming to both the American and European standards.     

Optimization of biodiesel produced from watermelon (Citrullus vulgaris) using batch-type production unit

In the present work the production of a biodiesel from watermelon seed oil (Citrullus vulgaris) by methanol-induced transesterification using an alkaline catalyst (potassium hydroxide, KOH) has been examined. The influence of the operating variables such as agitation speed, temperature, reaction time, alcohol amount, and catalyst concentration was determined experimentally and found to be 550 rpm agitation rate, 60°C reaction temperature, 55 min reaction time, 20% of methanol, and 13 g of catalysts concentration for 2.5 liters of oil. The yield of biodiesel from the watermelon methyl ester (WME) under optimized conditions is found to be 91%. The properties of biodiesel are measured as per ASTM standards and compared with the base diesel.     

Characterization and transesterification of Iranian bitter almond oil for biodiesel production

In the present work the production of biodiesel using bitter almond oil (BAO) in a potassium hydroxide catalyzed transesterification reaction was investigated. The BAO was obtained from resources available in Iran and its physical and chemical properties including iodine value, acid value, density, kinematic viscosity, fatty acid composition and mean molecular weight were specified. The low acid value of BAO (0.24 mg KOH/g) indicated that the pretreatment of raw oil with acid was not required. The fatty acid content analysis confirmed that the contribution of unsaturated fatty acids in the BAO is high (84.7 wt.%). Effect of different parameters including methanol to oil molar ratio (3–11 mol/mol), potassium hydroxide concentration (0.1–1.7% w/w) and reaction temperature (30–70 °C) on the production of biodiesel were investigated. The results indicated that these parameters were important factors affecting the tranesterification reaction. The fuel properties of biodiesel including iodine value, acid value, density, kinematic viscosity, saponification value, cetane number, flash point, cloud point, pour point and distillation characteristics were measured. The properties were compared with those of petroleum diesel, EN 14214 and ASTM 6751 biodiesel standards and an acceptable agreement was observed.     

Analysis and evaluation of operating variables for the yield of Karanja and neem oil-based biodiesel production

The aim of this research is to present the possibilities of the use of non-edible oils in biodiesel production, to consider the various methods for treatment of non-edible oils and to emphasise the influence of the operating and reaction conditions on the process rate and the ester yield. Because of biodegradability and non-toxicity biodiesel has become more attractive as alternative fuel. Biodiesel is produced mainly from vegetable oils by transesterification. For economic and social reasons, edible oils should be replaced by lower-cost and reliable feedstock for biodiesel production, such as non-edible plant oils. In this work biodiesel is produced from neem and Karanja by using butanol, propanol, ethanol and methanol as alcohols and KOH and NaOH as alkali catalysts by the transesterification process. The aim of this research is to analyse the different reaction parameters such as catalyst concentration, type of catalyst, types of alcohol, alcohol to oil molar ratio, reaction time and reaction temperature on the yield of biodiesel from non-edible oils. The maximum yield obtained was 95% with Karanja as oil with methanol and KOH as alkali catalyst at oil to alcohol molar ratio of 6:1 in 1 h at 60°C. Special attention is paid to the possibilities of producing biodiesel from non-edible oils.     

花椒籽油生物柴油制备工艺研究

以花椒籽油为原料,对KOH催化其与甲醇发生酯交换反应制备生物柴油进行研究。采用物理萃取法降低花椒籽油中游离脂肪酸的含量,三次萃取后酸值达到2 mgKOH/g以下。研究了花椒籽油和甲醇在氢氧化钾催化下的酯交换反应。进行了不同醇油摩尔比、催化剂用量、反应时间、反应温度等反应条件下对产率的影响,得到最佳反应条件为醇油物质的量之比为12∶1,催化剂添加量为油脂质量的1.2%,反应温度为60～65℃,反应时间为45 min。     

Optimization of biodiesel production from waste fish oil

The present study deals with the production of biodiesel using waste fish oil. The research assesses the effect of the transesterification parameters on the biodiesel yield and its properties, including temperature (40–60 °C), molar ratio methanol to oil (3:1–9:1) and reaction time (30–90 min). The experimental results were fitted to complete quadratic models and optimized by response surface methodology. All the biodiesel samples presented a FAME content higher than 93 wt.% with a maximum, 95.39 wt.%, at 60 °C, 9:1 of methanol to oil ratio and 90 min. On the other hand, a maximum biodiesel yield was found at the same methanol to oil ratio and reaction time conditions but at lower temperature, 40 °C, which reduced the saponification of triglycerides by the alkaline catalyst employed. Adequate values of kinematic viscosity (measured at 30 °C) were obtained, with a minimum of 6.30 mm²/s obtained at 60 °C, 5.15:1 of methanol to oil ratio and 55.52 min. However, the oxidative stability of the biodiesels produced must be further improved by adding antioxidants because low values of IP, below 2.22 h, were obtained. Finally, satisfactory values of completion of melt onset temperature, ranging from 3.31 °C to 3.83 °C, were measured.     

Intensification of continues biodiesel production process using a simultaneous mixer- separator reactor

Nowadays, Biodiesel as an alternative, sustainable and less toxic fuel has been accepted by both researchers and industry. Developing process intensification reactors with the aim of reaching more efficient process has captured the attention of many researchers recently. In order to examine a novel reactor for biodiesel production using Waste Cooking Oil as a cost-effective feedstock, and KOH as an efficient homogeneous catalyst, the present study was developed to investigate three effective parameters (Oil flow rate, catalyst concentration and reaction temperature) focusing on transesterification reaction yield in the Simultaneous Mixer-Separator (SMS) reactor, designed and fabricated exclusively for biodiesel production at Tarbiat Modares University (TMU). As the findings indicated, rising the flow rate presented an increasing trend up to 15 mL/min and a decreasing trend was found after this level. Also, catalyst concentration up to 1% w/w showed an increasing trend which was significant. Analysis of reaction temperature showed that at 60^°C the maximum yield is obtained. Furthermore, 15 mL/min oil flow rate, 1% w/w KOH concentration and 60^?C were selected as the optimal reaction conditions for continuous biodiesel production. At this point, the produced biodiesel followed by the purification step reached the yield of 96%. The produced biodiesel physicochemical properties were found to meet ASTM D6751 standard. All in all, continuous production capability, higher productivity, simultaneous separation of products, and the successful handling of waste resources distinguish the SMS reactor as a potential and efficient process intensification reactor.     

Biodiesel preparation from Jatropha oil catalyzed by KF/Red mud catalyst

Biodiesel preparation from Jatropha oil catalyzed by KF/Red mud (KF/RM) was studied. The optimum values of parameters for preparation of Jatropha oil biodiesel were obtained. The conversion rate of transesterification reached 92.2% under the optimum conditions, and the used KF/RM could be regenerated. Catalyst characterization showed that KOH and KFeF₄ were produced in KF/RM catalyst, which was crucial for the transesterification of Jatropha oil with methanol. Red mud was a good support to prepare KF-loaded catalyst, and prepared KF/RM was an excellent catalyst for biodiesel synthesis from Jatropha oil via transesterification reaction.     

Biodiesel production from Nerium oleander (Thevetia peruviana) oil through conventional and ultrasonic irradiation methods

In the present research work, Nerium oleander oil has been used as raw material for producing biodiesel using both ultrasonic transesterification and a magnetic stirrer method. A two-step transesterification process was carried out for optimum condition of 0.40% V/V methanol to oil ratio, 1% V/V H₂SO₄ catalyst, 55°C temperature, and 60 min reaction time followed by treatment with 0.2% V/V methanol to oil ratio, 1% V/W KOH alkaline catalyst, 55°C temperature, and 60 min reaction time. The process is repeated with an ultrasonic method at the frequency of 28 kHz using ultrasonic horn type reactor (50 W) for about 10–15 min. Biodiesel obtained from ultrasonic method and magnetic stirrer was then compared for their percentage yield and physiochemical properties. Ultrasonic transesterification process gave a maximum yield of 97% by weight of oleander biodiesel along with improved physiochemical characteristics. Therefore, it is concluded that ultrasonic method is the most effective method for converting crude oleander oil into biodiesel.     

Production of biodiesel at small-scale (10 L) for local power generation

The transesterification reaction of two different types of raw materials, a refined cooking oil and a used cooking sample, was performed at small scale (10 L) at the constant temperature of 65 °C. The effects of several reaction parameters, such as KOH wt% with respect to the oil weight, methanol/oil molar ratio and reaction time, were investigated. Biodiesel yields as good as 97.5 and 93.2% were achieved for the refined and the cooking oils, respectively, in the following conditions: 1.2 wt% of KOH as catalyst, a methanol/oil molar ratio of 6:1 and reaction time of 60 min.The properties of the biodiesel obtained starting from the used cooking oil are as good as those of the biodiesels obeying the European standards. The resulting product was used in a diesel electricity generator engine, which operated in real conditions. The results showed that biodiesel combustion leads to higher concentration of CO and to a lower emission of NO_x as compared to a petrodiesel-fueled engine. An optimization of the operating parameters of the engine would guarantee lower CO emissions in conformity with the regulation.     

Processing and characterization of biodiesel from sweet orange (Citrus sinensis) seed oil

Biodiesel is an eco-friendly fuel source which is produced from various oil sources. In this study, sinensis oil is tried as a biodiesel source. But seed is simply dumped as waste material to the environment. It contains 30–35% of oil content and can be processed by the transesterification method. The fatty acid profile of sinensis oil is analyzed by gas chromatography-mass spectrophotometer techniques. This study also describes the characterization and optimization of sinensis oil to biodiesel. The optimized biodiesel parameters were as follows: KOH catalyst, 6:1 molar ratio, 1.0 wt.% of catalyst concentration, 60°C temperature, and 120 min reaction time.     

Biodiesel production from olive–pomace oil of steam-treated alperujo

Recently interest has been revived in the use of plant-derived waste oils as renewable replacements for fossil diesel fuel. Olive–pomace oil (OPO) extracted from alperujo (by-product of processed olives for olive oil extraction), and produced it in considerable quantities throughout the Mediterranean countries, can be used for biodiesel production. A steam treatment of alperujo is being implemented in OPO extraction industry. This steam treatment improves the solid–liquid separation by centrifugation and facilitates the drying for further extraction of OPO. It has been verified that the steam treatment of this by-product also increases the concentration of OPO in the resulting treated solid, a key factor from an economic point of view. In the present work, crude OPO from steam-treated alperujo was found to be good source for producing biodiesel. Oil enrichment, acidity, biodiesel yield and fatty acid methyl ester composition were evaluated and compared with the results of the untreated samples. Yields and some general physicochemical properties of the quality of biodiesel were also compared to those obtained with other oils commonly used in biodiesel production. As for biodiesel yield no differences were observed. A transesterification process which included two steps was used (acid esterification followed by alkali transesterification). The maximum biodiesel yield was obtained using molar ratio methanol/triglycerides 6:1 in presence of sodium hydroxide at a concentration of 1% (w/w), reaction temperature 60 °C and reaction time 80 min. Under these conditions the process gave yields of about 95%, of the same order as other feedstock using similar production conditions.