A multi-variant approach to optimize process parameters for biodiesel extraction from rubber seed oil

Biodiesel is biodegradable, non-toxic and has the capacity for sustainable development, energy conservation and environmental preservation. Apart from yielding high value latex, the rubber plant supply large amount of rubber seed, which are currently underutilized. Extracting biodiesel from rubber seed is a viable option which demands attention for research to consolidate and optimize the process parameters. Design of experiments (DOE) is a powerful statistical approach which is used for optimizing the process parameters through two stage esterification process, relating acid and alkaline as catalyst. Reducing the acid value is the primary objective for process optimization in acid esterification process, whereas, maximizing the monoester yield is the objective for the alkaline-esterification process. Different saturated and unsaturated monoesters present in the biodiesel were quantified using gas chromatograph in order to determine the yield percentage, which ensures the quality of the biodiesel. The fuel was tested for properties such as viscosity, calorific value and carbon residue using standard test procedures and found to be analogous with diesel, which makes it possible to use this alternate fuel in the existing engine without any modification.     

Characterization and effect of using rubber seed oil as fuel in the compression ignition engines

Vegetable oils pose some problems when subjected to prolonged usage in compression ignition engines because of their high viscosity and low volatility. The common problems are poor atomization, carbon deposits, ring sticking, fuel pump failure, etc. Converting the high viscosity vegetable oil into its blends or esters can minimize these problems. The various blends of rubber seed oil and diesel were prepared and its important properties such as viscosity, calorific value, flash point, fire point, etc. were evaluated and compared with that of diesel. The blends were then subjected to engine performance and emission tests and compared with that for diesel. It was found that 50–80% of rubber seed oil blends gave the best performance. Long run tests were conducted using optimized blend and diesel. It was found that blend fueled engine has higher carbon deposits inside combustion chamber than diesel-fueled engine. Utilization of blends requires frequent cleaning of fuel filter, pump and the combustion chamber. Hence, it is recommended that rubber seed oil–diesel blend fuel is more suitable for rural power generation.     

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.     

Production of biodiesel from low priced,renewable and abundant date seed oil

The present work is definitely an approach towards attaining price competency of bio-diesel to petroleum diesel. The oils extracted from abundantly available waste of Zahidi, Basra and Khazravi date seeds were used to produce biodiesel using acid (HCl), base (KOH), immobilized enzyme (lipase), immobilized enzyme/acid (lipase/HCl) and immobilized enzyme/base (lipase/KOH) catalyzed processes. Mixed catalysis (immobilized enzyme + acid or immobilized enzyme + base) resulted in better yields in comparison to acid or base catalysis. The properties of biodiesel were evaluated by fuel standard tests and the results were compared with EN14214 and ASTM D6751 standards. Biodiesel produced from date seed oil was found to have a high cetane number (55–60.3), low iodine value (44–50) and good flash point (135–140 °C). Pour point of pure biodiesel produced from Khazravi and Zahidi was found to range from 2 to −2 °C. Biodiesel produced from Basra exhibited good pour point (−4.7 to −8.3 °C) in comparison to other varieties. The components present in biodiesel produced from various date varieties were determined by gas chromatographic-mass spectrometric analyses (GCMS). The fatty acid (%) detected in date seed biodiesel were oleic acid (33.4–47.4), lauric acid (19–28), palmitic acid (13.6–19.2), myristic acid (13.6–17.44) and linoleic acid (6.4–8.5). A special feature of date seed oil biodiesel was the presence of considerable amounts of low chain fatty acids.     

Synthesis of biodiesel from waste vegetable oil with large amounts of free fatty acids using a carbon-based solid acid catalyst

A carbon-based solid acid catalyst was prepared by the sulfonation of carbonized vegetable oil asphalt. This catalyst was employed to simultaneously catalyze esterification and transesterification to synthesis biodiesel when a waste vegetable oil with large amounts of free fatty acids (FFAs) was used as feedstock. The physical and chemical properties of this catalyst were characterized by a variety of techniques. The maximum conversion of triglyceride and FFA reached 80.5 wt.% and 94.8 wt.% after 4.5 h at 220 °C, when using a 16.8 M ratio of methanol to oil and 0.2 wt.% of catalyst to oil. The high catalytic activity and stability of this catalyst was related to its high acid site density (–OH, Brönsted acid sites), hydrophobicity that prevented the hydration of –OH species, hydrophilic functional groups (–SO₃H) that gave improved accessibility of methanol to the triglyceride and FFAs, and large pores that provided more acid sites for the reactants.     

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.     

Optimization of biodiesel production from camelina oil using orthogonal experiment

Camelina oil is a low-cost feedstock for biodiesel production that has received a great deal of attention in recent years. This paper describes an optimization study on the production of biodiesel from camelina seed oil using alkaline transesterification. The optimization was based on sixteen well-planned orthogonal experiments (OA₁₆ matrix). Four main process conditions in the transesterification reaction for obtaining the maximum biodiesel production yield (i.e. methanol quantity, reaction time, reaction temperature and catalyst concentration) were investigated. It was found that the order of significant factors for biodiesel production is catalyst concentration > reaction time > reaction temperature > methanol to oil ratio. Based on the results of the range analysis and analysis of variance (ANOVA), the maximum biodiesel yield was found at a molar ratio of methanol to oil of 8:1, a reaction time of 70 min, a reaction temperature of 50 °C, and a catalyst concentration of 1 wt.%. The product and FAME yields of biodiesel under optimal conditions reached 95.8% and 98.4%, respectively. The properties of the optimized biodiesel, including density, kinematic viscosity, acid value, etc., were determined and compared with those produced from other oil feedstocks. The optimized biodiesel from camelina oil meets the relevant ASTM D6571 and EN 14214 biodiesel standards and can be used as a qualified fuel for diesel engines.     

Accurate modeling of biodiesel production from castor oil using ANFIS

Research for finding alternative fuel sources has been concluded that the renewable fuels such as biodiesel can be used as an alternative to fossil fuels because of the energy security reasons and environmental benefits. In this contribution, transesterification of castor oil with methanol to form biodiesel has been modeled by using artificial neural network fuzzy interference system (ANFIS) approach. Methanol to oil molar ratio, catalyst amount (C), temperature (T), and time (S) were used as input parameters and fatty acid methyl ester yield was used as output parameter for modeling the efficiency of biodiesel production from castor oil. Obtaining low value of absolute deviation (2.2391), high value of R-squared (0.98704), and other modeling results proves that ANFIS modeling is an effective approach for biodiesel production from castor oil. In conclusion, comparison between our model and other previous predictive models reported in open literature indicates the priority of our model.     

Synthesis of biodiesel from vegetable oil with methanol catalyzed by Li-doped magnesium oxide catalysts

The preparation of a Li-doped MgO for biodiesel synthesis has been investigated by optimizing the catalyst composition and calcination temperatures. The results show that the formation of strong base sites is particularly promoted by the addition of Li, thus resulting in an increase of the biodiesel synthesis. The catalyst with the Li/Mg molar ratio of 0.08 and calcination temperature of 823 K exhibits the best performance. The biodiesel conversion decreases with further increasing Li/Mg molar ratio above 0.08, which is most likely attributed to the separated lithium hydroxide formed by excess Li ions and a concomitant decrease of BET values. In addition, the effects of methanol/oil molar ratio, reaction time, catalyst amount, and catalyst stability were also investigated for the optimized Li-doped MgO. The metal leaching from the Li-doped MgO catalysts was detected, indicating more studies are needed to stabilize the catalysts for its application in the large-scale biodiesel production facilities.     

The influence of seed and oil storage on the acid levels of rubber seed oil, derived from Hevea brasiliensis grown in Xishuangbanna, China

High acid levels, characteristic of rubber seed oil (RSO), limit RSO use in biodiesel production. The aims of this study were to determine the causes of these high acid levels by investigating what affects the storage of rubber seeds and RSO had on the acid levels. Two storage conditions/methods were evaluated, one representing a proposed storage method (SM 1), the other mimicking storage conditions characteristic to the Xishuangbanna region (SM 2). Furthermore, RSO storage was evaluated by testing RSO acid levels over a 2-month period, under standard storage conditions. Seeds from SM 2 displayed increased seed pile temperatures, higher levels of Mildew infection, lower seed oil content and higher acid levels. Low seed oil content and high acid values of SM 2 were resultant of the high Mildew infection and increased seed pile temperatures. In addition, a critical value of 90% relative humidity of seed piles was identified, above which Mildew infection increased sharply. Storage of crude RSO resulted in increased acid values. This data shows that in order to reduce high acid values, seed pile temperature, humidity and Mildew infections need to be kept to a minimum, as well as the storage time of the seeds and the RSO.     

Emission and engine performance analysis of a diesel engine using hydrogen enriched pomegranate seed oil biodiesel

The aim of this study is to determine the availability of pomegranate seed oil biodiesel (POB) as an alternative fuel in diesel engines and evaluate engine performance and emission characteristics of pure hydrogen enriched POB using diesel engine. For this purpose, the intake manifold of the test engine was modified and hydrogen enriched intake air was supplied throughout the experiments. Physical properties of POB and its blend with diesel fuel were also determined. The results showed that measured physical properties of POB are comparable with diesel fuel. According to engine performance experiments, although POB utilization has slight undesirable effects on some engine performance parameters such as brake power output and specific fuel consumption, it can be used as alternative fuel in diesel engines, by this way CO emission can be improved. Finally, hydrogen enrichment experiments indicated that pure hydrogen addition causes a slight improvement in both engine performance and exhaust emissions.     

NaOH impregnated sepiolite based heterogeneous catalyst and its utilization for the production of biodiesel from canola oil

NaOH/sepiolite nanocomposite heterogenous base catalyst (NaOH/sep.) was prepared via impregnation process and tested in a three-neck flask equipped with thermometer and reflux condenser for the production of biodiesel from transesterification of canola oil in an excess amount of methanol. The ratio of NaOH and sepiolite was selected as 1:4. The influence of various operational parameters was examined such as methanol to oil molar ratio, catalyst dosage, and reaction temperature. Untreated sepiolite and NaOH loaded sepiolite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy and Energy dispersive spectroscopy analysis. Overall NaOH/sep. based biodiesel production yield was examined by the help of Gas chromatography-mass spectrometry analysis. The yield was calculated from the peak areas as 80.93% which is better than that of expensive catalysis system using studies.     

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.     

Assessment of tree seed oil biodiesel: A comparative review based on biodiesel of a locally available tree seed

The present investigation is undertaken to investigate prospect of seeds of a locally available tree (koroch) for biodiesel production. The middle-size, evergreen koroch tree with spreading branches are available in Assam. The characteristics of koroch biodiesel and engine performance fueled by koroch biodiesel are also analyzed reviewing similar results available in the literature so as to ascertain its status. Twelve number of different tree seed oils, reported earlier, are considered for making the present comparative assessment. Though transesterification has been the common process for converting tree seed oil into biodiesel, as evidenced from the literature consulted in this study, but there have been variations of the chemical processes. Variations of the transesterification are attributed to (i) types of catalysis viz., acid (H₂SO₄) or base (KOH, NaOH, and NaOCH₃), (ii) reaction temperature, (iii) molar ratio, (iv) nature of reaction viz., single stage or multi-stage. The outputs of the reaction have also been found varying in terms of yield as well as quality. Quality of biodiesel, however, was found to influence by the nature of feedstock. The assessment of quality parameters was made either by ASTM D 6751 or EN 14214 standards. The major fuel properties such as calorific value, kinematic viscosity, cetane number and cloud point of the reference biodiesel (koroch biodiesel) are compared with the properties of five biodiesel obtained from non-edible tree seed (karanja, mahua, polonga, jatropha and rubber seed) and then ranked them in order of desirable property. No single biodiesel type could be found at top rank with reference to more than one property. With regards to viscosity, except rubber seed biodiesel, all other biodiesels (karanja, mahua, polonga, jatropha and koroch) fulfilled the ASTM D 6751 (1.9-6 cSt) as well as EN14214 (3.5-5) standards. Koroch biodiesel ranks 3rd, 3rd and 6th in case of kinematic viscosity, cetane number and calorific value amongst the biodiesel types considered for the present study. Cloud point of koroch, polanga, mahua, rubber, karanja and jatropha biodiesels are 4, 13.2, 5, 4, 12 and 4 °C. Further, properties of biodiesel were found to have influencing correlation with the fatty acid characteristics of the feedstock. Therefore, biodiesel with desirable properties could be expected form optimum mixing of different feedstock.Eleven number of different engine performance results pertaining to uses of biodiesel are also reviewed in this paper. Varying test conditions with reference to fuel types and blends, engine size and loading pattern are discussed. Engine performance results of koroch biodiesel were then compared with five similar tree-based biodiesel. It is observed that tree seed oil with more unsaturated fatty acids exhibits lower thermal efficiency compared to biodiesel having more saturated acids.     

Fuel properties of blend and biodiesel generated from acid oil using whole cell biocatalyst

Biodiesel was generated through whole cell catalyzed transesterification of acid oil, to the extent of up to 92%. The fuel properties of biodiesel (B100) and its blend (B20) were determined and compared with standard biodiesel as per American Society for Testing and Materials (ASTM) standard (ASTM D6751). B100 and B20 showed good pour point of ?26°C and ?29°C, respectively, indicating their operation viability in colder environment. Other properties of biodiesel are quite similar to petroleum diesel and ASTM standard. The results of this study reveal the potential use of acid oil as feedstock for generation of fuel grade biodiesel through biocatalyzed transesterification.     

Effect of incompletely converted soybean oil on biodiesel quality

Presence of fully converted monoalkyl esters is the major requirement in quality biodiesel. Due to high associated costs with testing and widespread production of biodiesel not only in commercial scale but also in small scale, there is a high propensity of substandard biodiesel entering the market and being used in compression ignition engines. Due to this reason, it is important to understand how low grade biodiesel with a lower methyl ester conversion affects the parameters of quality standards and as a result, engine performance and durability. In this paper, the performance of fatty acid methyl esters with different proportions of unconverted triglycerides has been evaluated. The study has comprehensively evaluated the effect of unconverted triglycerides on flash point, water and sediment, kinematic viscosity, sulfur content, sulfated ash, copper strip corrosion, cetane number, cloud point, carbon residue, acid number, free glycerin, total glycerin, phosphorus content and distillation temperature.     

Calcium-based mixed oxide catalysts for methanolysis of Jatropha curcas oil to biodiesel

Calcium-based mixed oxides catalysts (CaMgO and CaZnO) have been investigated for the transesterification of Jatropha curcas oil (JCO) with methanol, in order to evaluate their potential as heterogeneous catalysts for biodiesel production. Both CaMgO and CaZnO catalysts were prepared by coprecipitation method of the corresponding mixed metal nitrate solution in the presence of a soluble carbonate salt at ∼ pH 8-9. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed desorption of CO₂ (CO₂-TPD), scanning electron microscopy (SEM) and N₂ adsorption (BET). The conversion of JCO by CaMgO and CaZnO were studied and compared with calcium oxide (CaO), magnesium oxide (MgO) and zinc oxide (ZnO) catalysts. Both CaMgO and CaZnO catalysts showed high activity as CaO and were easily separated from the product. CaMgO was found more active than CaZnO in the transesterification of JCO with methanol. Under the suitable transesterification conditions at 338 K (catalyst amount = 4 wt. %, methanol/oil molar ratio = 15, reaction time = 6 h), the JCO conversion of more than 80% can be achieved over CaMgO and CaZnO catalysts. Even though CaO gave the highest activity, the conversion of JCO decreased significantly after reused for forth run whereas the conversion was only slightly lowered for CaMgO and CaZnO after sixth run.     

Optimization of conversion of waste rapeseed oil with high FFA to biodiesel using response surface methodology

In the present study, waste rapeseed oil with high free fatty acids (FFA) was used as feedstock for producing biodiesel. In the pretreatment step, FFA was reduced by distillation refining method. Then, biodiesel was produced by alkaline-catalyzed transesterification process, which was designed according to the 2⁴ full-factorial central composite design. The response surface methodology (RSM) was used to optimize the conditions for the maximum conversion to biodiesel and understand the significance and interaction of the factors affecting the biodiesel production. The results showed that catalyst concentration and reaction time were the limiting conditions and little variation in their value would alter the conversion. At the same time, there was a significant mutual interaction between catalyst concentration and reaction time.The biodiesel produced in the present experiment was analyzed by gas chromatography/mass spectrometry (GC/MS), which showed that it mainly contained six fatty acid methyl esters. In addition, the diesel indexes analysis showed that most of the fuel properties were in reasonable agreement with the 0# diesel standard of China (GB252-2000) and the biodiesel standard of America (ASTM D6751).     

Optimization of a batch CaO-catalyzed transesterification of used domestic waste oil with methanol and elucidation of a mathematical correlation between biodiesel yield and percent conversion

ABSTRACT

The major drawback of the wide applicability of biodiesel is its price compared to the conventional petro-diesel. The feedstock and the applied catalyst in the transesterification reaction are the main contributor for the overall cost of the biodiesel production. Thus, this study summarizes the optimization of a batch transesterification reaction of used domestic waste oil (UDWO) with methanol using CaO, which can be easily prepared from different cheap and readily available natural sources. Quadratic model equations were elucidated describing the effect of methanol:oil molar ratio, CaO concentration wt.%, reaction temperature °C, reaction time h, and mixing rate rpm on biodiesel yield and conversion percentage. The optimum operating conditions were found to be competitive with those of the high-cost immobilized enzyme Novozym435. An overall acceptable agreement was achieved between the produced biodiesel, its blends with petro-diesel and the available commercial petro-diesel, and the international fuel standards. A precise and reliable logarithmic mathematical model was predicted correlating the production of pure high-quality biodiesel yield with the conversion percentage which were measured based on the fatty acid methylester content and decrease in viscosity, respectively.     

Measurement of monochromatic emissivity of cement clinker with various Fe2O3 content at high temperature

An applicatiopn of the optical pyrometer is studied for measuring monochromatic emissivities of cement clinker with various Fe2O3 contnet.The idsa of using “brightness temperature” is introduced into the eimssivity measurement.In this method,there is no need for measuring an actual temperature of sample surfaces,only with determining both brightness temperatures of a sample and a blackbody can the required emissivity be evaluated according to Wien‘s radiation law.In practice,the cement clinker is regarded as a greybody,the monochromatic emissivity is approximately equal to the total emissivity,so a single-colour optical pyrometer is applied for this purpose,Test measurements are carried out on 10 kinds of cement clinkers,Experimental data are treated by the least square method.As a result ,the emissivity variation with temperature at a certain Fe2O3 content is quite well represented by εn=a+bT.Furthermore,this work first reported that the eimissivities of cement clinker change consierably with Fe2O3 contents.In multiple cement production this conclusion is very important.