A review on feedstocks, production processes, and yield for different generations of biodiesel

Microalgae has been identified as a potential feedstock for biodiesel production since its cultivation requires less cropland compared to conventional oil crops and the high growth rate of microalgae. Research on microalgae oils often are focused on microalgae oil extraction and biomass harvesting techniques. However, energy intensive and costly lipid extraction methods are the major obstacles hampering microalgae biodiesel commercialisation. Direct biodiesel synthesis avoids such problems as it combines lipid extraction techniques and transesterification into a single step. In this review, the potential of direct biodiesel synthesis from microalgae biomass was comprehensively analysed. The various species of microalgae commonly used as biodiesel feedstock was critically assessed, particularly on high lipid content species. The production of microalgae biodiesel via direct conversion from biomass was systematically discussed, covering major enhancements such as heterogeneous catalysts, the use of ultrasonic and microwave- techniques and supercritical alcohols that focus on the overall improvement of biodiesel production. In addition, this review illustrates the cultivation conditions for biomass growth and lipid productivity improvement, the available harvesting and lipid extraction technologies, as well as the key challenges and future prospect of microalgae biodiesel production. This review serves as a basis for future research on direct biodiesel synthesis from modified microalgae biomass to improve profitability of microalgae biodiesel.

Sustainability of direct biodiesel synthesis from microalgae biomass: a critical review.

In the effect of robust industrialization and rapid augmentation of a number of fleets, there has been a huge rise in the fossil fuel consumption. Tremendous increase in global warming threatens the ecological balance of the earth. Based on the recent sorts of hardship about the fuel, researchers are profoundly pondered over the field of renewability, environmentally friendly and economically doable. In recent decades biodiesel fuel becomes the center of attraction among researchers since it is renewable, bio degradable, non-noxious, eco-friendly and sustainable. This review paper highlights and reviews the properties of prosperous variety of the biodiesel fuels derived from non-edible feedstocks which are termed as third generation biodiesel and its effects on the performance and emissions of the diesel engines. It was observed that the physicochemical properties of the biodiesel differ based on the types of feedstocks and also have a considerable effect on the potential performance of engine and dynamic characteristics of emission level. Also, the usage of biodiesel commonly leads to a reduction in noxious pollutants like carbon monoxide, unburnt hydrocarbon and particulate matter with an obvious increase in fuel consumption and NOx emission. This review provides a prospective strategy for the researchers for enhancing the engine performance and emission characteristics by using the third generation biofuels and its blends with the productive marvelous outcomes.

A review on the properties, performance and emission aspects of the third generation biodiesels

Transportation and shipping activities are major contributor to air pollution at sea where most of it occurs as a result of exhaust emissions from ships. Stringent emission limitations enforced by the International Maritime Organization have hastened the need to find a new alternative fuel for marine diesel engines. Thus, biodiesel fuel was chosen as one of the environmentally friendly alternative energy that can reduce ship toxic gas emissions and at the same time reduces dependence on petroleum-based fuels. Therefore, the purpose of this paper is to provide a comprehensive review of biodiesel as an alternative fuel for marine diesel engine applications. This review covers the biodiesel fuel background, engine performance, history, recent progress, engine warranty, issues, challenges, and possible solutions on using biodiesel for marine applications. A significant number of literatures from indexed journals were cited accordingly. The results of previous studies had shown that the use of biodiesel would mostly increase the amount of brake specific fuel consumption and nitrogen oxide gas while conversely reducing other toxic gas emissions. Although a number of issues and challenges arise, most marine engine manufacturers give conditional warranty against the use of biodiesel in the engines. The study concluded that biodiesel and its blends have a bright future in the marine sector, provided some of the highlighted issues can be solved.

Biodiesel as alternative fuel for marine diesel engine applications: a review.

A comprehensive review on the environmental impacts of diesel/biodiesel additives

Many researches have been carried out towards the reduction in noxious emissions from diesel engines This paper reviews the studies on the outcomes of operating parameters discrepancy on the engine emission issues carried out by various authors in different diesel engines fuelled with biodiesel from different feedstocks The main goal of this paper is to enlighten the momentous of injection parameters like injection timing and injection pressure on the engine emission characteristics This paper touches upon the advancement and retardation methods of fuel injection timing and injection pressure to inspect the engine emission indicators such as carbon monoxide, hydrocarbon, oxides of nitrogen, smoke, particulate matter and carbon dioxide contents Comparative evaluation has been conversed accompanied by apropos causes for the deviation of emission characteristics

Effects of fuel injection parameters on emission characteristics of diesel engines operating on various biodiesel: A review

Due to the unstable nature of bio-oil, it becomes mandatory to analyze the changes in physical and chemical properties of the bio-oil during storage to appreciate its chemical instability, for developing stabilization strategies. The present study aims to investigate the oxidative and thermal stability of bio-oil extracted from pyrolyzing Calophyllum inophyllum (CI) deoiled seed cake in a fixed bed reactor at 500 °C under the constant heating rate of 30 °C/min. Each stability analysis method involve an accelerated aging procedure based on standards established by ASTM (D5304 and E2009) and European standard (EN 14112). Fourier Transform Infrared Spectroscopy and Gas Chromatography-Mass Spectrometry were employed to analytically characterize the un-aged and aged bio-oil samples. The results clearly depict that stabilizing Calophyllum inophyllum bio-oil with 10% (w/w) methanol improved its stability than that of the crude sample. Addition of methanol reduced the change in viscosity of bio-oil by 38.55% during accelerated aging process. The oxidation stability index of bio-oil stabilized with methanol was found to be 3.97 h which is in accordance with ASTM D6751. FT-IR and GC-MS results showed an increase in the relative concentration of C-O (carboxylic acids, ethers and esters) and C=O (carbonyl) functional groups in aged bio-oil samples.

Experimental investigation on improvement of storage stability of bio-oil derived from intermediate pyrolysis of Calophyllum inophyllum seed cake

The scarcity of the petroleum resources creates the search for their alternate non-petroleum fuels for IC engines to meet out the elevating energy consumption rates and also to form the eco-friendly surroundings. The specific characteristics such as sustainability, uncontaminated burning and renewability put forward bio-fuel as the appropriate substitute. The main complexity experienced by the researchers in the bio-fuel implementation is its effective adaptability to the engines by compensating all performance, emission and combustion characteristics. This review paper evaluates the researches on the above issues carried out by numerous scientists concerning the operating parameters of Compression Ignition (CI) engine fuelled by various biodiesel to become accustomed to the engine effectively and eco-friendly. The main aim of this paper is to offer the significance of compression ratio on the well-organized engine characteristics. This paper highlights the techniques of compression ratio modifications to explore the performance indicators (brake specific fuel consumption, brake thermal efficiency, brake specific energy consumption and exhaust gas temperature), emission indicators (carbon monoxide, hydrocarbon, oxides of nitrogen, smoke, particulate matter and carbon dioxide contents) and combustion indicators (in-cylinder pressure, peak cylinder pressure, heat release rate, ignition delay period and combustion duration). Comparative evaluation has been concluded accompanied by the pertinent reasons for the deviation of engine characteristics.

Assessment on the Influence of Compression Ratio on the Performance, Emission and Combustion Characteristics of Diesel Engine Fuelled with Biodiesel

This research article aims to analyze the properties and characteristics of the products obtained from slow pyrolysis of wood barks of matured Calophyllum inophyllum (CI) tree. The bio-oil, gas and biochar obtained from the slow pyrolysis carried out at 550 °C in a fixed bed batch type reactor at a heating rate of 30 °C min−1 were characterized by different analytical techniques. Owing to the lofty volatile content of CI biomass (72.61%), it was chosen as the raw material in this current experimental investigation. FT-IR and GC–MS results of bio-oil showed the existence of elevated amount phenol derivatives, oxygenated compounds, acids, esters and furans. The physicochemical properties of the bio-oil sample were tested in accordance with ASTM standards which clearly showed that bio-oil is a highly viscous liquid with lower heating value as compared to that of diesel fuel. The chemical composition of pyrolytic gas was analyzed by using Gas Chromatography which revealed the presence of combustible organic components. The FT-IR results of biochar showed the presence of aromatic and aliphatic hydrocarbons whereas the increased amount of carbon in biochar reveals its potential to be used as solid fuel for commercial purposes.

R. Purnachandran

Papers

A review on the properties, performance and emission aspects of the third generation biodiesels

Effects of fuel injection parameters on emission characteristics of diesel engines operating on various biodiesel: A review

Experimental investigation on improvement of storage stability of bio-oil derived from intermediate pyrolysis of Calophyllum inophyllum seed cake

Assessment on the Influence of Compression Ratio on the Performance, Emission and Combustion Characteristics of Diesel Engine Fuelled with Biodiesel

A Complete Analytical Characterization of Products Obtained from Pyrolysis of Wood Barks of Calophyllum inophyllum