A.M. Ashraful

Bio: A.M. Ashraful is an academic researcher from University of Malaya. The author has contributed to research in topics: Biodiesel & Diesel fuel. The author has an hindex of 18, co-authored 25 publications receiving 1977 citations. Previous affiliations of A.M. Ashraful include University of Melbourne.

The prospects of biolubricants as alternatives in automotive applications

Abstract: Lubricants perform as anti-friction media. They facilitate smooth operations, maintain reliable machine functions, and reduce the risks of frequent failures. At present, the increasing prices of crude oil, the depletion of crude oil reserves in the world, and global concern in protecting the environment from pollution have renewed interest in developing and using environment-friendly lubricants derived from alternative sources. A biolubricant is renewable lubricants that is biodegradable, non-toxic, and emits net zero greenhouse gas. This study presents the potential of a biolubricant based on vegetable oil as an alternative lubricant according to studies published in highly rated journals in scientific indices. In the first part of this paper, the source, properties, as well as advantages and disadvantages of the biolubricant are discussed. The second part describes the potential of vegetable oil-based biolubricants as alternative lubricants for automobile applications. The final part describes the world biolubricant market and its future prospects. Biolubricants are potential alternative lubricants because of their low toxicity, good lubricating properties, high viscosity index, high ignition temperature, increased equipment service life, high load-carrying abilities, good anti-wear characteristic, excellent coefficient of friction, natural multi-grade properties, low evaporation rates, and low emissions into the atmosphere.

Effect of antioxidants on oxidation stability of biodiesel derived from vegetable and animal based feedstocks

Abstract: The increase of energy demand coped with utilization of fossil resources have engendered serious environmental impact. The progressively stringent worldwide emission legislation and increasing greenhouse gas emission require significant research effort on alternative fuels. Therefore, biodiesels are becoming important increasingly due to its ease in adaptation, environmental benefits and prospect in energy security. Biodiesel derived from vegetable oils, waste cooking oils and animal fats are long chain fatty acid alkyl esters, which contains unsaturated portions that are susceptible to oxidation. Biodiesel oxidation is a complex process having a number of mechanisms involved. Autoxidation radical chain reactions are the primary cause of biodiesel degradation that leads to formation of hydroperoxide, which, after that decompose to form an array of secondary oxidation products like aldehydes, ketones, carboxylic acids, oligomers, gum, sediment etc. Antioxidants are often used to inhibit biodiesel oxidative degradation. The present review attempts to cover the inhibition action of natural and synthetic antioxidants, methods used to analyze biodiesel oxidation and their effect on biodiesel derived from various feedstocks. Phenolic antioxidants are more effective compared to amine antioxidants. Pyrogallol is found to be the most effective antioxidant to improve the oxidation stability in case of almost all biodiesels reviewed.

Performance and emission assessment of diesel-biodiesel-ethanol/bioethanol blend as a fuel in diesel engines: a review.

Abstract: The aim of this review is to study the opportunities and prospects of introducing diesel–biodiesel–ethanol/bioethanol blend as fuel in the existing diesel engines. The study is based on the engine emissions and its performance. The energy policies and the ever growing energy demand of the world, require an alternative to fossil fuels. In this quest, the diesel–ethanol blend or the diesohol blend might be a good option. But this blend possesses stability problem as well as inferior physicochemical properties when compared to diesel fuel and needs additives to remain stable. When biodiesel is used as an additive in this diesohol blend, it improves the physicochemical properties of the ternary blend, engine performance and also increases the renewable portion of the blend. First the engine performance and emissions data found by using diesel–biodiesel–ethanol/bioethanol ternary blends are accumulated. Then the results of the scientists and investigators are discussed to evaluate its potential as an alternative to fossil diesel fuel. The physicochemical properties of ternary blends are found to be almost similar to the diesel fuel. These ternary blends significantly reduce the PM (particulate matter) emissions from the diesel engine but the emissions of NO x (nitrogen oxides), soot and smoke, HC (hydrocarbon), CO (carbon monoxide), CO 2 (carbon dioxide) and the carbonyl compounds depend on the operating conditions of the engine and remain almost similar to the diesel fuel exhaust.

Non-edible vegetable oils: A critical evaluation of oil extraction, fatty acid compositions, biodiesel production, characteristics, engine performance and emissions production

Abstract: World energy demand is expected to increase due to the expanding urbanization, better living standards and increasing population. At a time when society is becoming increasingly aware of the declining reserves of fossil fuels beside the environmental concerns, it has become apparent that biodiesel is destined to make a substantial contribution to the future energy demands of the domestic and industrial economies. There are different potential feedstocks for biodiesel production. Non-edible vegetable oils which are known as the second generation feedstocks can be considered as promising substitutions for traditional edible food crops for the production of biodiesel. The use of non-edible plant oils is very significant because of the tremendous demand for edible oils as food source. Moreover, edible oils’ feedstock costs are far expensive to be used as fuel. Therefore, production of biodiesel from non-edible oils is an effective way to overcome all the associated problems with edible oils. However, the potential of converting non-edible oil into biodiesel must be well examined. This is because physical and chemical properties of biodiesel produced from any feedstock must comply with the limits of ASTM and DIN EN specifications for biodiesel fuels. This paper introduces non-edible vegetable oils to be used as biodiesel feedstocks. Several aspects related to these feedstocks have been reviewed from various recent publications. These aspects include overview of non-edible oil resources, advantages of non-edible oils, problems in exploitation of non-edible oils, fatty acid composition profiles (FAC) of various non-edible oils, oil extraction techniques, technologies of biodiesel production from non-edible oils, biodiesel standards and characterization, properties and characteristic of non-edible biodiesel and engine performance and emission production. As a conclusion, it has been found that there is a huge chance to produce biodiesel from non-edible oil sources and therefore it can boost the future production of biodiesel.

Overview of the production of biodiesel from Waste cooking oil

Abstract: In recent years, biodiesel has attracted significant attention from researchers, governments, and industries as a renewable, biodegradable, and non-toxic fuel. However, several feedstocks have been proven impractical or infeasible because of their extremely high cost due to their usage primarily as food resources. Waste cooking oil (WCO) is considered the most promising biodiesel feedstock despite its drawbacks, such as its high free fatty acid (FFA) and water contents. This review paper provides a comprehensive overview of the pre-treatment and the usage of WCO for the production of biodiesel using several methods, different types of reactors, and various types and amounts of alcohol and catalysts. The most common process in the production of biodiesel is transesterification, and using a methanol–ethanol mixture will combine the advantages of both alcohols in biodiesel production. In addition, this paper highlights the purification and analysis of the produced biodiesel, operating parameters that highly affect the biodiesel yield, and several economic studies. This review suggests that WCO is a promising feedstock in biodiesel production.

Production, characterization and performance of biodiesel as an alternative fuel in diesel engines – A review

Abstract: Due to the finite stock of fossil fuels and its negative impact on the environment, many countries across the world are now leaning toward renewable sources energies like solar energy, wind energy, biofuel, hydropower, geothermal and ocean energy to ensure energy for the countries development security. Biodiesel is one kind of biofuel that is renewable, biodegradable and has similar properties of fossil diesel fuel. The aim of this paper is to provide the substantial information on biodiesel to the researchers, engineers and policy makers. To achieve the goal, this paper summarizes the information on biofuel development, feedstocks around the world, oil extraction technic, biodiesel production processes. Furthermore, this paper will also discuss the advantages of biodiesel compared to fossil fuel. Finally, the combustion behavior of biodiesel in an internal combustion engine is discussed and it will help the researchers and policy maker and manufacturer. To determine the future and goal of automotive technology the study found that, feedstock selection for biodiesel production is very important as it associates 75% production cost. Moreover, the test of fuel properties is very important before using in the engine which depends on the type of feedstocks, origin country, and production process. Most of the researchers reported that the use of biodiesel in diesel engine reduces engine power slightly but reduces the harmful emission significantly. Finally, the study concludes that biodiesel has the potential to be used as a diesel fuel substitute in diesel engines to solve the energy and environment crisis.

A comprehensive review on properties of edible and non-edible vegetable oil-based biodiesel: Composition, specifications and prediction models

Abstract: In recent decades, the concern over depletion of the world׳s petroleum reserves and environmental pollution has increased the demand to develop a renewable and environmental friendly fuel. Biodiesel, which mainly consists of Fatty Acid Methyl Esters (FAME) is one of the best substitutes for diesel fuel. Currently, vegetable oils, edible or non-edible, are the main resources of biodiesel. This review aims at providing comprehensive information and analyzes on biodiesel produced from edible and non-edible vegetable oils, their composition and specifications. Accordingly, the Fatty Acid (FA) profiles of 28 edible vegetable oils and 40 non-edible vegetable oils were collected. Their main specifications including sulfur content, density, viscosity, flash point, cloud point, pour point, cold filter plugging point, cetane number, iodine number, heating value, acid value and carbon residual before and after transesterification (vegetable oil and biodiesel, respectively) were analyzed in detail. Many researchers have developed prediction models to quantify biodiesel specifications to optimize its manufacturing and obtain biodiesel with the best specifications. Three factors that are especially influential are the fatty acids profiles, the degree of unsaturation within the FA structures and molecular weight. Accordingly, many models have been constructed on these features. There are also models that quantify the relationship between the biodiesel specifications and its thermodynamic properties or other specifications. Accordingly, the second part of this work was conducted on the existing prediction models. All the models were discussed along with their deviation in prediction.

Resource Recovery from Wastewater by Biological Technologies: Opportunities, Challenges, and Prospects

Abstract: Limits in resource availability are driving a change in current societal production systems, changing the focus from residues treatment, such as wastewater treatment, toward resource recovery. Biotechnological processes offer an economic and versatile way to concentrate and transform resources from waste/wastewater into valuable products, which is a prerequisite for the technological development of a cradle-to-cradle bio-based economy. This review identifies emerging technologies that enable resource recovery across the wastewater treatment cycle. As such, bioenergy in the form of biohydrogen (by photo and dark fermentation processes) and biogas (during anaerobic digestion processes) have been classic targets, whereby, direct transformation of lipidic biomass into biodiesel also gained attention. This concept is similar to previous biofuel concepts, but more sustainable, as third generation biofuels and other resources can be produced from waste biomass. The production of high value biopolymers (e.g., for bioplastics manufacturing) from organic acids, hydrogen, and methane is another option for carbon recovery. The recovery of carbon and nutrients can be achieved by organic fertilizer production, or single cell protein generation (depending on the source) which may be utilized as feed, feed additives, next generation fertilizers, or even as probiotics. Additionlly, chemical oxidation-reduction and bioelectrochemical systems can recover inorganics or synthesize organic products beyond the natural microbial metabolism. Anticipating the next generation of wastewater treatment plants driven by biological recovery technologies, this review is focused on the generation and re-synthesis of energetic resources and key resources to be recycled as raw materials in a cradle-to-cradle economy concept.