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.     

Performance and emission evaluation of a diesel engine fueled with methyl esters of rubber seed oil

Recent concerns over the environment, increasing fuel prices and scarcity of its supply have promoted the interest in development of the alternative sources for petroleum fuels. At present, biodiesel is commercially produced from the refined edible vegetable oils such as sunflower oil, palm oil and soybean oil, etc. by alkaline-catalyzed esterification process. This process is not suitable for production of biodiesel from many unrefined non-edible vegetable oils because of their high acid value. Hence, a two-step esterification method is developed to produce biodiesel from high FFA vegetable oils. The biodiesel production method consists of acid-catalyzed pretreatment followed by an alkaline-catalyzed transesterification. The important properties of methyl esters of rubber seed oil are compared with other esters and diesel. Pure rubber seed oil, diesel and biodiesel are used as fuels in the compression ignition engine and the performance and emission characteristics of the engine are analyzed. The lower blends of biodiesel increase the brake thermal efficiency and reduce the fuel consumption. The exhaust gas emissions are reduced with increase in biodiesel concentration. The experimental results proved that the use of biodiesel (produced from unrefined rubber seed oil) in compression ignition engines is a viable alternative to diesel.     

Biodiesel production from renewable feedstocks: Status and opportunities

The increased demand for energy, climate change, and energy security concerns has driven the research interest for the development of alternative fuel from plant origin. Biodiesel derived from plant oils, which include edible and non-edible oil have gained interest for the last two decades as alternative for diesel around the world. Among these plant origin oils more than 95% of biodiesel production feedstocks come from edible oils, because they are readily available in many regions. The major advantage of these feedstocks is the properties of biodiesel produced from them are suitable to be used as diesel fuel substitute. But the consequence is the increase demand of the feedstock for food as well as fuel. A sustainable alternative fuel should be derived from renewable non-food biomass sources. The main objective of this review is to give an overview on the synthesis of biodiesel through esterification and transesterification using non-edible oil resources which are available in India, and available processes for synthesis of biodiesel (acid-, base-catalyzed transesterification reactions (homogeneous and heterogeneous), their importance, and which is the commercial process also discussed here.     

Biodiesel production from non-edible plant oils

Because of biodegradability and nontoxicity biodiesel has become more attractive as alternative fuel. Biodiesel is produced mainly from vegetable oils by transesterification of triacylglycerols. From economic and social reasons, edible oils should be replaced by lower-cost and reliable feedstocks for biodiesel production such as non-edible plant oils. This paper reviews various methods for biodiesel production from common non-edible oils employing alcoholysis reactions. The aim of this paper is to present the possibilities of the use of non-edible oils into biodiesel production, to consider the various methods for treatment of non-edible oils and to emphasize the influence of the operating and reaction conditions on the process rate and the ester yield. The special attention is paid to the possibilities of optimization, kinetics and improvement of biodiesel production from non-edible oils.     

Biodiesel production process optimization and characterization to assess the suitability of the product for varied environmental conditions

In this study, both edible (coconut oil, palm oil, groundnut oil, and rice bran oil) and non-edible oils (pongamia, neem and cotton seed oil) were used to optimize the biodiesel production process variables like catalyst concentration, amount of methanol required for reaction, reaction time and reaction temperature. The fuel properties like specific gravity, moisture content, refractive index, acid value, iodine number, saponification value and peroxide value were estimated. Based on the cetane number and iodine value, the methyl esters obtained from palm and coconut oils were not suitable to use as biodiesel in cold weather conditions, but for hot climate condition biodiesel obtained from the remaining oil sources is suitable.     

Quality analysis studies on biodiesel production of neochloris oleoabundans algae

The petroleum fuels play a major role in industry, agriculture, and transport besides meeting out many other basic human needs. However, fossil fuels are limited in quantity and are depleting day by day as the consumption is increasing very rapidly. Biodiesel is one such fuel in which there is a lot of hope. In the recent past, biodiesel received considerable attention as a renewable fuel. In India, it has not been possible to produce biodiesel from edible oils since the same is very scarce. Hence, the scope of opting to non-edible oils from plants as raw material for biodiesel production recently gained momentum. This paper presents the production of biodiesel from nonedible, Neochloris oleoabundans oil and its characterization. The studies were carried out on transesterification of oil with methanol, sodium hydroxide, and Sodium methoxide as catalyst for the production of biodiesel. The process parameters such as catalyst concentration, reaction time, and reaction temperature were optimized for the production of Neochloris oleoabundans oil biodiesel. The biodiesel yield of 95.15% was noticed at optimal process parameters.     

Performance and emission characteristics of a DI compression ignition engine operated on Honge, Jatropha and sesame oil methyl esters

The high viscosity of vegetable oils leads to problem in pumping and spray characteristics. The inefficient mixing of vegetable oils with air contributes to incomplete combustion. The best way to use vegetable oils as fuel in compression ignition (CI) engines is to convert it into biodiesel. Biodiesel is a methyl or ethyl ester of fatty acids made from vegetable oils (both edible and non-edible) and animal fat. The main resources for biodiesel production can be non-edible oils obtained from plant species such as Pongamia pinnata (Honge oil), Jatropha curcas (Ratanjyot), Hevea brasiliensis (Rubber) and Calophyllum inophyllum (Nagchampa). Biodiesel can be used in its pure form or can be blended with diesel to form different blends. It can be used in CI engines with very little or no engine modifications. This is because it has properties similar to mineral diesel. This paper presents the results of investigations carried out on a single-cylinder, four-stroke, direct-injection, CI engine operated with methyl esters of Honge oil, Jatropha oil and sesame oil. Comparative measures of brake thermal efficiency, smoke opacity, HC, CO, NO_X, ignition delay, combustion duration and heat release rates have been presented and discussed. Engine performance in terms of higher brake thermal efficiency and lower emissions (HC, CO, NO_X) with sesame oil methyl ester operation was observed compared to methyl esters of Honge and Jatropha oil operation.     

Feasibility of edible oil vs. non-edible oil vs. waste edible oil as biodiesel feedstock

Biodiesel has high potential as a new and renewable energy source in the future, as a substitution fuel for petroleum-derived diesel and can be used in existing diesel engine without modification. Currently, more than 95% of the world biodiesel is produced from edible oil which is easily available on large scale from the agricultural industry. However, continuous and large-scale production of biodiesel from edible oil without proper planning may cause negative impact to the world, such as depletion of food supply leading to economic imbalance. A possible solution to overcome this problem is to use non-edible oil or waste edible oil (WEO). In this context, the next question that comes in mind would be if the use of non-edible oil overcomes the short-comings of using edible oil. Apart from that, if WEO were to be used, is it sufficient to meet the demand of biodiesel. All these issues will be addressed in this paper by discussing the advantages and disadvantages of using edible oil vs. non-edible vs. WEO as feedstock for biodiesel production. The discussion will cover various aspects ranging from oil composition, oil yield, economics, cultivation requirements, land availability and also the resources availability. Finally, a proposed solution will be presented.     

Biodiesel production from Jatropha curcas oil

In view of the fast depletion of fossil fuel, the search for alternative fuels has become inevitable, looking at huge demand of diesel for transportation sector, captive power generation and agricultural sector, the biodiesel is being viewed a substitute of diesel. The vegetable oils, fats, grease are the source of feedstocks for the production of biodiesel. Significant work has been reported on the kinetics of transesterification of edible vegetable oils but little work is reported on non-edible oils. Out of various non-edible oil resources, Jatropha curcas oil (JCO) is considered as future feedstocks for biodiesel production in India and limited work is reported on the kinetics of transesterification of high FFA containing oil. The present study reports a review of kinetics of biodiesel production. The paper also reveals the results of kinetics study of two-step acid–base catalyzed transesterification process carried out at pre-determined optimum temperature of 65 and 50 °C for esterification and transesterification process, respectively, under the optimum condition of methanol to oil ratio of 3:7 (v/v), catalyst concentration 1% (w/w) for H₂SO₄ and NaOH and 400 rpm of stirring. The yield of methyl ester (ME) has been used to study the effect of different parameters. The maximum yield of 21.2% of ME during esterification and 90.1% from transesterification of pretreated JCO has been obtained. This is the first study of its kind dealing with simplified kinetics of two-step acid–base catalyzed transesterification process carried at optimum temperature of both the steps which took about 6 h for complete conversion of TG to ME.     

Experimental investigation of control of NOx emissions in biodiesel-fueled compression ignition engine

Biodiesel is an alternative fuel consisting of the alkyl esters of fatty acids from vegetable oils or animal fats. Vegetable oils are produced from numerous oil seed crops (edible and non-edible), e.g., rapeseed oil, linseed oil, rice bran oil, soybean oil, etc. Research has shown that biodiesel-fueled engines produce less carbon monoxide (CO), unburned hydrocarbon (HC), and particulate emissions compared to mineral diesel fuel but higher NO_x emissions. Exhaust gas recirculation (EGR) is effective to reduce NO_x from diesel engines because it lowers the flame temperature and the oxygen concentration in the combustion chamber. However, EGR results in higher particulate matter (PM) emissions. Thus, the drawback of higher NO_x emissions while using biodiesel may be overcome by employing EGR. The objective of current research work is to investigate the usage of biodiesel and EGR simultaneously in order to reduce the emissions of all regulated pollutants from diesel engines. A two-cylinder, air-cooled, constant speed direct injection diesel engine was used for experiments. HCs, NO_x, CO, and opacity of the exhaust gas were measured to estimate the emissions. Various engine performance parameters such as thermal efficiency, brake specific fuel consumption (BSFC), and brake specific energy consumption (BSEC), etc. were calculated from the acquired data. Application of EGR with biodiesel blends resulted in reductions in NO_x emissions without any significant penalty in PM emissions or BSEC.     

Effect of blends of Palm-Jatropha-Pongamia biodiesels on cloud point and pour point

To minimize use of biodiesels synthesized from edible oils like Palm due to raising food versus fuel issue, Palm biodiesel (PBD) was blended with biodiesels derived from tree borne non-edible oil seeds Jatropha, and Pongamia to examine the effect on cloud point (CP) and pour point (PP) of PBD. Dependence of CP and PP on esters of fatty acid composition was also examined. Good correlations between CP and palmitic acid methyl ester (PAME) and between PP and PAME were obtained. A correlation between CP and total unsaturated fatty acid methyl ester (X) was also obtained and correlation between PP and X was also determined. Using these four correlations, cloud and pour points of different biodiesel blends can be determined.     

Activity of homogeneous and heterogeneous catalysts,spectroscopic and chromatographic characterization of biodiesel: A review

Biofuel has got tremendous attraction for the last decade as an alternative source of energy. Bioethanol and biodiesel are two main products of first generation biofuel. Biodiesel is chemically fatty acid methyl esters prepared from various edible and non-edible oils. It has been used as a substitute to mineral diesel during the last decade. This review is about generation, transesterification, factors affecting transesterification, catalysts (homogeneous and heterogeneous) and physico-chemical characterization of biodiesel by chromatographic and spectroscopic techniques. The alkaline homogeneous catalysts (NaOH or KOH) have been used on commercial scale for production of biodiesel because these are cheap and reaction occurs in less time. The heterogeneous catalysts such as metal oxides, e.g., CaO, MgO, SrO, ZnO, La₂O₃, Mg–Al hydrolalcite have been used for transesterification of vegetable oil due to their easy separation and reuse but these catalysts take more time for completion of reaction. The yield of biodiesel may be affected by alcohol/oil ratio, concentration of catalyst, time required for reaction, temperature free fatty acid moisture. The prepared biodiesel has been characterized by chromatographic techniques like gas chromatography, gas chromatography–mass spectroscopy, high performance liquid chromatography and spectroscopic techniques like nuclear magnetic resonance and infrared spectroscopy.     

Blends of biodiesels synthesized from non-edible and edible oils: Influence on the OS (oxidation stability)

Biodiesels jatropha and pongamia synthesized from their respective non-edible seed oils, and PBD (palm biodiesel) synthesized from edible oil were blended with different weight ratios to examine the influence on the OS (oxidation stability). Dependence of the OS on esters of fatty acid composition was also examined. Good correlation between the OS and PAME (palmitic acid methyl ester) was obtained. A correlation between the OS and X (total unsaturated fatty acid methyl ester) was also obtained. Using these correlations, OS of different biodiesel blends can be determined.     

Plant oils as fuels for compression ignition engines: A technical review and life-cycle analysis

As an alternative fuel for compression ignition engines, plant oils are in principle renewable and carbon-neutral. However, their use raises technical, economic and environmental issues. A comprehensive and up-to-date technical review of using both edible and non-edible plant oils (either pure or as blends with fossil diesel) in CI engines, based on comparisons with standard diesel fuel, has been carried out. The properties of several plant oils, and the results of engine tests using them, are reviewed based on the literature. Findings regarding engine performance, exhaust emissions and engine durability are collated. The causes of technical problems arising from the use of various oils are discussed, as are the modifications to oil and engine employed to alleviate these problems. The review shows that a number of plant oils can be used satisfactorily in CI engines, without transesterification, by preheating the oil and/or modifying the engine parameters and the maintenance schedule. As regards life-cycle energy and greenhouse gas emission analyses, these reveal considerable advantages of raw plant oils over fossil diesel and biodiesel. Typical results show that the life-cycle output-to-input energy ratio of raw plant oil is around 6 times higher than fossil diesel. Depending on either primary energy or fossil energy requirements, the life-cycle energy ratio of raw plant oil is in the range of 2–6 times higher than corresponding biodiesel. Moreover, raw plant oil has the highest potential of reducing life-cycle GHG emissions as compared to biodiesel and fossil diesel.     

Comparison of palm oil, Jatropha curcas and Calophyllum inophyllum for biodiesel: A review

The world today is faced with serious global warming and environmental pollution. Besides, fossil fuel will become rare and faces serious shortage in the near future. This has triggered the awareness to find alternative energy as their sustainable energy sources. Biodiesel as a cleaner renewable fuel has been considered as the best substitution for diesel fuel due to it being used in any compression ignition engine without any modification. The main advantages of using biodiesel are its renewability and better quality of exhaust gas emissions. This paper reviews the production, performance and emission of palm oil, Jatropha curcas and Calophyllum inophyllum biodiesel. Palm oil is one of the most efficient oil bearing crops in terms of oil yield, land utilization, efficiency and productivity. However, competition between edible oil sources as food with fuel makes edible oil not an ideal feedstock for biodiesel production. Therefore, attention is shifted to non-edible oil like Jatropha curcas and Calophyllum inophyllum. Calophyllum inophyllum oil can be transesterified and being considered as a potential biodiesel fuel. Compared to Palm oil and Jatropha biodiesel industry, biodiesel from Calophyllum inophyllum is still in a nascent state. Therefore, long term endurance research and tribological studies need to be carried out before Calophyllum inophyllum oil base biodiesel can become an alternative fuel in future.     

Comparison of performance characteristics of agricultural tractor diesel engine operating on home and industrially produced biodiesel

Owing to unstable diesel fuel prices in the world market, many farmers have been looking for alternative fuels. Vegetable oils are one of the alternatives, which can be used as fuel in diesel engines either in the form of straight vegetable oil or in the form of biodiesel. This study aims to present experimental data by utilization of home and industrial biodiesel as fuel in an agricultural tractor diesel engine. The home biodiesel production was made from different vegetable oils (crude rapeseed, edible sunflower and waste oil) with the process of one‐stage‐based catalyzed transesterification. A commercially available agricultural tractor ZETOR 7745 was employed. Measurements were taken on the power take‐off shaft by electrical dynamometer FROMENT XT200. According to the results, agricultural tractor diesel engine operating on home biodiesel fuels had better performance characteristics related to industrially produced biodiesel and similar to conventional diesel fuel. Copyright © 2009 John Wiley & Sons, Ltd.     

Enhancement in Jatropha-based biodiesel yield by process optimisation using design of experiment approach

Edible and non-edible oils are used for the production of biodiesel from the last so many years and these oils are extracted from their respective seeds. Jatropha oil is used as a feedstock to produce biodiesel for running the Compression Ignition engine. A statistical model is developed to interrelate the trans-esterification process variables for the biodiesel yield using design of experiment approach by selecting central composite design of a response surface methodology. Results shown in this paper indicate that the optimum observed yield of 95.5% has the following reaction conditions: Molar ratio 19.84 (% v/v), reaction time 3 h, reaction temperature 70°C, catalyst concentration 4.18 wt% and stirrer rpm 650. Also, the yield produced is higher when compared with 93.5% which was observed by Lee paper using the same methodology. Moreover, the fuel properties of Jatropha biodiesel are closer to the ASTM standard of biodiesel.     

Oxidation stability of biodiesel derived from high free fatty acid feedstock

At present, with fluctuating feedstock prices, the biodiesel manufacturing industries are facing some downfall. High free fatty acid (FFA) non-edible oil, which is a byproduct of vegetable oil refineries, is available at low price and in considerable quantities at vegetable oil refinery sites. This high FFA oil can be utilized as a potential low cost feedstock for biodiesel production. In the present work, high FFA (51.6%) oil was synthesized into biodiesel by a two-step process. Except oxidation stability, other fuel properties of the produced biodiesel were found to be comparable with that of biodiesel specifications. Oxidation stability was found to be only 2.1 h at 110°C as determined by the Rancimat apparatus.

In order to study and further improve the oxidation stability, the biodiesel (B100) was dosed with a suitable antioxidant (pyrogallol) and stored for 6 months. The acid value, peroxide value, and kinematic viscosity which are closely associated with oxidation behavior were studied. It was found that biodiesel dosed with an antioxidant showed the least increase in the acid value, peroxide value, and kinematic viscosity. Also, induction period was improved and found to be within the American Society for Testing and Materials limit . Thus, the high FFA oil-based biodiesel with a suitable antioxidant can be used as a potential feedstock to resolve the issue of the high cost of biodiesel production.     

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.