Integrated Environmental Assessment of sunflower oil production

The high energy and petroleum based fuels demand of the world require use of alternative fuels from materials available within each country. Therefore biofuels may be an alternative to mineral diesel. A local pilot production of sunflower oil was implemented in order to test the possibility to reduce fossil fuels consumption on a local scale. Vegetable oils can be directly obtained from oilseed plants and can be used as energy sources in internal combustion engines.Environmental Impact Indicators were provided by Material Flow Accounting, Embodied Energy Analysis and Emergy Accounting. All three approaches reveal that the agricultural phase is the critical step in the whole production line from the point of view of environmental impact. The renewability calculated for the sunflower oil is 33.6%.A comparative Life Cycle Assessment analysis for the sunflower oil production line from conventional farming with organic farming showed environmental advantages.Furthermore use of vegetable oils instead of diesel oil as energy sources in internal combustion engines reduces carbon dioxide emissions of 59%.This study represents an opportunity for farms to reduce dependence on petroleum and to explore energy production systems exploiting renewable energy.     

Current and Potential Biofuel Production from Plant Oils

Environmental concerns and depletion of fossil fuels along with government policies have led to the search for alternative fuels from various renewable and sustainable feedstocks. This review provides a critical overview of the chemical composition of common commercial plant oils, i.e., palm oil, olive oil, rapeseed oil, castor oil, WCO, and CTO and their recent trends toward potential biofuel production. Plant oils with a high energy content are primarily composed of triglycerides (generally >?95%), accompanied by diglycerides, monoglycerides, and free fatty acids. The heat content of plant oils is close to 90% for diesel fuels. The oxygen content is the most important difference in chemical composition between fossil oils and plant oils. Triglycerides can even be used directly in diesel engines. However, their high viscosity, low volatility, and poor cold flow properties can lead to engine problems. These problems require that plant oils need to be upgraded if they are to be used as a fuel in conventional diesel engines. Biodiesel, biooil, and renewable diesel are the three major biofuels obtained from plant oils. The main constraint associated with the production of biodiesel is the cost and sustainability of the feedstock. The renewable diesel obtained from crude tall oil is more sustainable than biofuels obtained from other feedstocks. The fuel properties of renewable diesel are similar to those of fossil fuels with reduced greenhouse gas emissions. In this review, the chemical composition of common commercial plant oils, i.e., palm oil, olive oil, rapeseed oil, castor oil, and tall oil, are presented. Both their major and minor components are discussed. Their compositions and fuel properties are compared to both fossil fuels and biofuels.     

Influence of fatty acid composition of raw materials on biodiesel properties

The aim of this work was the study of the influence of the raw material composition on biodiesel quality, using a transesterification reaction. Thus, ten refined vegetable oils were transesterificated using potassium methoxide as catalyst and standard reaction conditions (reaction time, 1h; weight of catalyst, 1 wt.% of initial oil weight; molar ratio methanol/oil, 6/1; reaction temperature, 60 degrees C). Biodiesel quality was tested according to the standard [UNE-EN 14214, 2003. Automotive fuels. Fatty acid methyl esters (FAME) for diesel engines. Requirements and test methods]. Some critical parameters like oxidation stability, cetane number, iodine value and cold filter plugging point were correlated with the methyl ester composition of each biodiesel, according to two parameters: degree of unsaturation and long chain saturated factor. Finally, a triangular graph based on the composition in monounsaturated, polyunsaturated and saturated methyl esters was built in order to predict the critical parameters of European standard for whatever biodiesel, known its composition.     

Influence of fatty acid methyl esters from hydroxylated vegetable oils on diesel fuel lubricity

Current and future regulations on the sulfur content of diesel fuel have led to a decrease in lubricity of these fuels. This decreased lubricity poses a significant problem as it may lead to wear and damage of diesel engines, primarily fuel injection systems. Vegetable oil based diesel fuel substitutes (biodiesel) have been shown to be clean and effective and may increase overall lubricity when added to diesel fuel at nominally low levels. Previous studies on castor oil suggest that its uniquely high level of the hydroxy fatty acid ricinoleic acid may impart increased lubricity to the oil and its derivatives as compared to other vegetable oils. Likewise, the developing oilseed Lesquerella may also increase diesel lubricity through its unique hydroxy fatty acid composition. This study examines the effect of castor and Lesquerella oil esters on the lubricity of diesel fuel using the High-Frequency Reciprocating Rig (HFRR) test and compares these results to those for the commercial vegetable oil derivatives soybean and rapeseed methyl esters.     

Ethanol-diesel fuel blends -- a review

Ethanol is an attractive alternative fuel because it is a renewable bio-based resource and it is oxygenated, thereby providing the potential to reduce particulate emissions in compression-ignition engines. In this review the properties and specifications of ethanol blended with diesel fuel are discussed. Special emphasis is placed on the factors critical to the potential commercial use of these blends. These factors include blend properties such as stability, viscosity and lubricity, safety and materials compatibility. The effect of the fuel on engine performance, durability and emissions is also considered. The formulation of additives to correct certain key properties and maintain blend stability is suggested as a critical factor in ensuring fuel compatibility with engines. However, maintaining vehicle safety with these blends may entail fuel tank modifications. Further work is required in specifying acceptable fuel characteristics, confirming the long-term effects on engine durability, and ensuring safety in handling and storing ethanol-diesel blends.     

Compartmentation of triacylglycerol accumulation in plants

Triacylglycerols from plants, familiar to most people as vegetable oils, supply 25% of dietary calories to the developed world and are increasingly a source for renewable biomaterials and fuels. Demand for vegetable oils will double by 2030, which can be met only by increased oil production. Triacylglycerol synthesis is accomplished through the coordinate action of multiple pathways in multiple subcellular compartments. Recent information has revealed an underappreciated complexity in pathways for synthesis and accumulation of this important energy-rich class of molecules.     

Alternative fuel properties of tall oil fatty acid methyl ester-diesel fuel blends

In this experimental work, tall oil methyl ester-diesel fuel blends as alternative fuels for diesel engines were studied. Tall oil methyl ester was produced by reacting tall oil fatty acids with methyl alcohol under optimum conditions. The blends of tall oil methyl ester-diesel fuel were tested in a direct injection diesel engine at full load condition. The effects of the new fuel blends on the engine performance and exhaust emission were tested. It was observed that the engine torque and power output with tall oil methyl ester-diesel fuel blends increased up to 6.1% and 5.9%, respectively. It was also seen that CO emissions decreased to 38.9% and NO(x) emissions increased up to 30% with the new fuel blends. The smoke opacity did not vary significantly.     

Diesel particulate emissions from used cooking oil biodiesel

Two different biodiesel fuels, obtained from waste cooking oils with different previous uses, were tested in a DI diesel commercial engine either pure or in 30% and 70% v/v blends with a reference diesel fuel. Tests were performed under a set of engine operating conditions corresponding to typical road conditions. Although the engine efficiency was not significantly affected, an increase in fuel consumption with the biodiesel concentration was observed. This increase was proportional to the decrease in the heating value. The main objective of the work was to study the effect of biodiesel blends on particulate emissions, measured in terms of mass, optical effect (smoke opacity) and size distributions. A sharp decrease was observed in both smoke and particulate matter emissions as the biodiesel concentration was increased. The mean particle size was also reduced with the biodiesel concentration, but no significant increases were found in the range of the smallest particles. No important differences in emissions were found between the two tested biodiesel fuels.     

The use of a fuel containing Chlorella vulgaris in a diesel engine

There is a need for sustainable fuels for diesel engines and fuels containing particles will function as a fuel in diesel engines. Some microalgae such as Chlorella vulgaris are unicellular and 5–10 μm in size, which is suitable for combining in an emulsion fuel. An emulsion consisting of transesterified rapeseed oil, a surfactant and a slurry of C. vulgaris was used as a fuel in an unmodified single cylinder diesel engine. The fuel consumption and emissions of this fuel was determined and although the carbon monoxide levels were higher the NO_x emission was lower than that of diesel.     

Construction of combustion models for rapeseed methyl ester bio-diesel fuel for internal combustion engine applications

Bio-diesel fuels are non-petroleum-based diesel fuels consisting of long chain alkyl esters produced by the transesterification of vegetable oils, that are intended for use (neat or blended with conventional fuels) in unmodified diesel engines. There have been few reports of studies proposing theoretical models for bio-diesel combustion simulations. In this study, we developed combustion models based on ones developed previously. We compiled the liquid fuel properties, and the existing detailed mechanism of methyl butanoate ester (MB, C₅H₁₀O₂) oxidation was supplemented by sub-mechanisms for two proposed fuel constituent components, C₇H₁₆ and C₇H₈O (and then, by mp2d, C₄H₆O₂ and propyne, C₃H₄) to represent the combustion model for rapeseed methyl ester described by the chemical formula, C₁₉H₃₄O₂ (or C₁₉H₃₆O₂). The main fuel vapor thermal properties were taken as those of methyl palmitate C₁₉H₃₆O₂ in the NASA polynomial form of the Burcat database. The special global reaction was introduced to “crack” the main fuel into its constituent components. This general reaction included 309 species and 1472 reactions, including soot and NO_x formation processes. The detailed combustion mechanism was validated using shock-tube ignition-delay data under diesel engine conditions. For constant volume and diesel engine (Volvo D12C) combustion modeling, this mechanism could be reduced to 88 species participating in 363 reactions.     

Biodiesel production via enzymatic catalysis

A review of current work in biodiesel production via enzymatic catalysis has been done. The parameters of the process as determined by laboratories are represented and analyzed. The main factors affecting interesterification are considered. The major types of oils and alcohols used in biodiesel synthesis are listed. The means of lipase enzyme immobilization, including exposure on the cell surface, are discussed.     

Applied models to biodegradation kinetics of lubricant and vegetable oils in wastewater

Bioremediation technologies are used in order to remove pollutants from the environment in a safe, economical and harmless way during the treatment of waste, especially with the use of techniques such as biodegradation. A lubricant and vegetable oil contaminated water sample was studied in order to evaluate the biodegradability of different types of oils, considering the relevance of the obtained data in the bioremediation procedures. The objective of this paper is to use respirometry technique as a biodegradation process data source, and then apply to the obtained data the experimental design of mathematical models to characterize and determinate how the different types of oils are capable of affecting the parameters in biodegradation kinetics. The kinetics was then evaluated through selected models with a reasonable fit to experimental data. The Bartha and Pramer respirometer is used as a method to accurately measure the CO₂ formation in the organic compounds degradation by microorganisms. Therefore, the difference in biodegradation efficiency process is compared in the different groups of oils using mathematical models fitting the obtained data for the kinetics of biodegradation. The results demonstrated that used lubricant automotive oils are more susceptible to the biodegradation process, since their molecular structures had already been altered after use. In general, automotive lubricant oils shown better performance in biodegradation than vegetable oils. The models proposed for the obtained data in each of these assays demonstrated that vegetable oils biodegradation rate tends to decrease faster and end sooner than the automotive oils. Also, the modeling predicted that higher rates of biodegradation and total CO₂ production are to be expected in automotive lubricant oils rather than vegetable oils.     

Mechanism and challenges in commercialisation of algal biofuels

Biofuels made from algal biomass are being considered as the most suitable alternative energy in current global and economical scenario. Microalgae are known to produce and accumulate lipids within their cell mass which is similar to those found in many vegetable oils. The efficient lipid producer algae cell mass has been reported to contain more than 30% of their cell weight as lipids. According to US DOE microalgae have the potential to produce 100 times more oil per acre land than any terrestrial plants. This article reviews up to date literature on the composition of algae, mechanism of oil droplets, triacylglycerol (TAG) production in algal biomass, research and development made in the cultivation of algal biomass, harvesting strategies, and recovery of lipids from algal mass. The economical challenges in the production of biofuels from algal biomass have been discussed in view of the future prospects in the commercialisation of algal fuels.     

Energy production from biomass (Part 2): Conversion technologies

The use of biomass to provide energy has been fundamental to the development of civilisation. In recent times pressures on the global environment have led to calls for an increased use of renewable energy sources, in lieu of fossil fuels. Biomass is one potential source of renewable energy and the conversion of plant material into a suitable form of energy, usually electricity or as a fuel for an internal combustion engine, can be achieved using a number of different routes, each with specific pros and cons. A brief review of the main conversion processes is presented, with specific regard to the production of a fuel suitable for spark ignition gas engines.     

Biodeterioration of crude oil and oil derived products: a review

Biodeterioration of crude oil and oil fuels is a serious economic and an environmental problem all over the world. It is impossible to prevent penetration of microorganisms in oil and fuels both stored in tanks or in oilfields after drilling. Both aerobic and anaerobic microorganisms tend to colonise oil pipelines and oil and fuel storage installations. Complex microbial communities consisting of both hydrocarbon oxidizing microorganisms and bacteria using the metabolites of the former form an ecological niche where they thrive. The accumulation of water at the bottom of storage tanks and in oil pipelines is a primary prerequisite for development of microorganisms in fuels and oil and their subsequent biological fouling. Ability of microorganisms to grow both in a water phase and on inter-phase of water/hydrocarbon as well as the generation of products of their metabolism worsen the physical and chemical properties of oils and fuels. This activity also increases the amount of suspended solids, leads to the formation of slimes and creates a variety of operational problems. Nowadays various test-systems are utilized for microbial monitoring in crude oils and fuels; thus allowing an express determination of both the species and the quantities of microorganisms present. To suppress microbial growth in oils and fuels, both physico-mechanical and chemical methods are applied. Among chemical methods, the preference is given to substances such as biocides, additives, the anti-freezing agents etc that do not deteriorate the quality of oil and fuels and are environmentally friendly. This review is devoted to the analysis of the present knowledge in the field of microbial fouling of crude oils and oil products. The methods utilized for monitoring of microbial contamination and prevention of their undesirable activities are also evaluated. The special focus is given to Russian scientific literature devoted to crude oil and oil products biodeterioration.     

Influence of vegetable oils fatty-acid composition on biodiesel optimization

Biodiesel is an alternative fuel for diesel engines produced through transesterification of oleaginous feedstocks. To analyze the influence of the fatty-acid composition on biodiesel optimization, transesterification of several vegetable oils has been studied. Reactions were carried out in flasks filled with vegetable oils, heated to the reaction temperature and stirred at 1100 rpm. The reactions started when the methanol and potassium hydroxide solutions were added to the flasks. Concentration of catalyst, amount of methanol, reaction temperature and time were optimized using a factorial design and a surface response design. Also, a kinetics study was carried out to optimize the reaction time. Results showed that reaction parameters optimal values depend on the oil chemical and physical properties. It can be concluded from this field trial that the effect of both catalyst concentration and reaction time over the transesterification yield is greatly influenced by the saturation degree and fatty-acid chain length.     

Preparation and characterization of bio-diesels from various bio-oils

Methyl, ethyl, 2-propyl and butyl esters were prepared from canola and linseed oils through transesterification using KOH and/ or sodium alkoxides as catalysts. In addition, methyl and ethyl esters were prepared from rapeseed and sunflower oils using the same catalysts. Chemical composition of the esters was determined by HPLC for the class of lipids and by GC for fatty acid compositions. The bio-diesel esters were characterized for their physical and fuel properties including density, viscosity, iodine value, acid value, cloud point, pure point, gross heat of combustion and volatility. Methyl and ethyl esters prepared from a particular vegetable oil had similar viscosities, cloud points and pour points, whereas methyl, ethyl, 2-propyl and butyl esters derived from a particular vegetable oil had similar gross heating values. However, their densities, which were 2 7% higher than those of diesel fuels, statistically decreased in the order of methyl approximately 2-propyl > ethyl > butyl esters. Butyl esters showed reduced cloud points (-6 degrees C to -10 degrees C) and pour points (-13 degrees C to -16 degrees C) similar to those of summer diesel fuel having cloud and pour points of -8 degrees C and -15 degrees C, respectively. The viscosities of bio-diesels (3.3-7.6 x 10(-4) Pa s at 40 degrees C) were much less than those of pure oils (22.4-45.1 x 10(-4) Pa s at 40 degrees C) and were twice those of summer and winter diesel fuels (3.50 and 1.72 x 10(-4) Pa s at 40 degrees C), and their gross heat contents of approximately 40 MJ/kg were 11% less than those of diesel fuels (approximately 45 MJ/kg). For different esters from the same vegetable oil, methyl esters were the most volatile, and the volatility decreased as the alkyl group grew bulkier. However, the bio-diesels were considerably less volatile than the conventional diesel fuels.     

Improving sensitivity in proteome studies by analysis of false discovery rates for multiple search engines

LC‐MS experiments can generate large quantities of data, for which a variety of database search engines are available to make peptide and protein identifications. Decoy databases are becoming widely used to place statistical confidence in result sets, allowing the false discovery rate (FDR) to be estimated. Different search engines produce different identification sets so employing more than one search engine could result in an increased number of peptides (and proteins) being identified, if an appropriate mechanism for combining data can be defined. We have developed a search engine independent score, based on FDR, which allows peptide identifications from different search engines to be combined, called the FDR Score. The results demonstrate that the observed FDR is significantly different when analysing the set of identifications made by all three search engines, by each pair of search engines or by a single search engine. Our algorithm assigns identifications to groups according to the set of search engines that have made the identification, and re‐assigns the score (combined FDR Score). The combined FDR Score can differentiate between correct and incorrect peptide identifications with high accuracy, allowing on average 35% more peptide identifications to be made at a fixed FDR than using a single search engine.     

Influence of vegetable oils fatty acid composition on reaction temperature and glycerides conversion to biodiesel during transesterification

Presence of unreacted glycerides in biodiesel may reduce drastically its quality. This is why conversion of raw material in biodiesel through transesterification needs to readjust reaction parameter values to complete. In the present work, monitoring of glycerides transformation in biodiesel during the transesterification of vegetable oils was carried out. To check the influence of the chemical composition on glycerides conversion, selected vegetable oils covered a wide range of fatty acid composition. Reactions were carried out under alkali-transesterification in the presence of methanol. In addition, a multiple regression model was proposed. Results showed that kinetics depends on chemical and physical properties of the oils. It was found that the optimal reaction temperature depends on both length and unsaturation degree of vegetable oils fatty acid chains. Vegetable oils with higher degree of unsaturation exhibit faster monoglycerides conversion to biodiesel. It can be concluded that fatty acid composition influences reaction parameters and glycerides conversion, hence biodiesel yield and economic viability.