Biodiesel is envisaged as environmentally benign fuel due to its unique properties, such as biodegradability, renewability and non-toxicity. Its utilisation leads to the reduction of sulphur oxide ...and greenhouse gas emissions as it produces quite lower amounts of carbon and sulphur based gases in comparison to conventional fossil fuels. This paper is a review of the recent achievements of the cleaner intensification technologies for biodiesel production. Merits and limitations of the cleaner intensification technologies have been discussed. Mechanical stirring via transesterification is the most common and extensively utilised for biodiesel production. It involves the conversion of oil to glycerol and acid alkyl ester while employing methanol. However, this process has an inherent drawback of mass transfer resistance resulting in a lower reaction rate and higher production cost. Intensification technologies have become more attractive to overcome these aforementioned problems. In a bid to increase the cost competitiveness of biodiesel production compared to diesel fuel, process intensification has been studied for numerous biodiesel processing technologies. Many researchers have resorted to several intensification technologies namely; microwave, ultrasonic cavitation and hydrodynamic cavitation reactor to eliminate the mass transfer resistance of immiscible reactants. Once the mass transfer resistance is reduced, it may lead to a shorter reaction time and lower energy consumptions compared to mechanical stirring. Recent studies reveal that microwave and ultrasonic cavitation techniques are not yet completely feasible for biodiesel production at industrial scale. On the other hand, it was found that hydrodynamic cavitation offers a number of advantages over other intensification technologies. It shows good performance with respect to product yield, reaction time, energy consumption and product quality. Furthermore, it exhibits a sustainable mean for energy recovery from renewable oils. It was concluded that more studies are needed to extend the existing information of hydrodynamic cavitation for the design of the plate geometry with respect to the methyl ester conversion. This will help to develop a sustainable and industrially viable route for energy recovery from renewable oils. Yield efficiency in relation to the method followed the order: hydrodynamic cavitation > microwave > ultrasonic cavitation > mechanical stirring.
•Cleaner intensification technologies for biodiesel production.•Merits and limitations of the intensification technologies have been discussed.•Process intensification is time saving and energy efficient process.
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•Hydrodynamic cavitation resulted in significant process intensification.•Waste cooking oil is a sustainable feedstock for biodiesel production.•The properties of the produced fuel ...met EN 14214 and ASTM D 6751.
This paper investigates a new route for intensification of methyl ester synthesis in Malaysia via alkali-catalysed transesterification of waste cooking oil derived from palm olein using a hydrodynamic cavitation reactor. The effects of the oil to methanol molar ratio (1:4–1:7), catalyst loading concentration (0.5–1.25wt%) and reaction temperature (50–65°C) have been investigated using an optimised plate with 21 holes of 1mm diameter and an inlet pressure of 2bar in a 50L of hydrodynamic cavitation reactor assisted by a double diaphragm pump. Optimal conversion of 98.1% was achieved in 15min in a hydrodynamic cavitation reactor with 1:6 molar ratio of oil to methanol, 1wt% of catalyst and 60°C of reaction temperature. It has been observed that a significant reduction in the optimum reaction time (about 6 fold) for transesterification from 90min for mechanical stirring approach to 15min for the hydrodynamic cavitation approach. Optimal yield efficiency of 12.50×10−4g/J was found using hydrodynamic cavitation and it was 8 fold higher than 1.5×10−4g/J when mechanical stirring was used.
Development of cleaner biodiesel production related to hydrodynamic cavitation of methyl ester synthesis from sustainable waste cooking oil via alkali-catalysed transesterification is gaining ...importance due to considerable lower energy requirement and time. The effects of the oil to methanol molar ratio (1:4–1:7), catalyst concentration (0.5–1.25 wt %) and reaction temperature (50–65 °C) have been studied in a hydrodynamic cavitation and mechanical stirring system. Highest conversion of 98% was achieved under optimum conditions of 1:6 M ratio of oil to methanol, 1 wt % potassium hydroxide as alkali catalyst, 60 °C and 15 min reaction time. It has been observed that yield efficiency and reaction time were 833% higher and 600% shorter using hydrodynamic cavitation compared to mechanical stirring. Triglycerides conversion obeys pseudo-first order mechanism. The kinetic parameters of hydrodynamic cavitation and mechanical stirring were calculated, where the reaction rate constants were 0.238 and 0.031 min−1, activation energies were 89.7 and 92.7 kJ/mol and the pre-exponential factors were 2.623 × 1013 and 1.120 × 1013 min−1. Hydrodynamic cavitation was 1.8 fold more energy efficient and 4.6 fold lower feedstock used per produced product than mechanical stirring in biodiesel production. In conclusion, waste cooking oil methyl ester produced via hydrodynamic cavitation proved to be time saving and energy efficient compared to mechanical stirring. This makes the process more environmental friendly using hydrodynamic cavitation.
•About 7.7 fold higher rate constant using HC compared to mechanical stirring.•About 2.3 fold higher frequency factor using HC than mechanical stirring.•The activation energy for HC and mechanical stirring were 89.7 and 92.7 kJ/mol.•About 4.6 fold lower feedstock per product using HC than mechanical stirring.
•HC reactor for pretreatment of RSO at pilot scale with 50L capacity.•New designed four orifice plates studied at inlet pressure (1–3.5bar).•Pre and post optimised conditions found for orifice plate ...and reaction parameters.•HC found to be 3-fold shorter time compared to MS.•HC have 4-fold higher esterified efficiency than MS.
Pretreatment of the high free fatty acid rubber seed oil (RSO) via esterification reaction has been investigated by using a pilot scale hydrodynamic cavitation (HC) reactor. Four newly designed orifice plate geometries are studied. Cavities are induced by assisted double diaphragm pump in the range of 1–3.5bar inlet pressure. An optimised plate with 21 holes of 1mm diameter and inlet pressure of 3bar resulted in RSO acid value reduction from 72.36 to 2.64mgKOH/g within 30min of reaction time. Reaction parameters have been optimised by using response surface methodology and found as methanol to oil ratio of 6:1, catalyst concentration of 8wt%, reaction time of 30min and reaction temperature of 55°C. The reaction time and esterified efficiency of HC was three fold shorter and four fold higher than mechanical stirring. This makes the HC process more environmental friendly.
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•Carthamus lanatus L. seed oil used for biodiesel production by using CoWO3@rGO.•CoWO3@rGO is a novel, green and recyclable catalyst.•The properties of the produced fuels met EN ...14,214 and ASTM D 6751.•The optimal Carthamus lanatus L. biodiesel yield was predicted using RSM.•The green nanocomposite can be reused seven times without losing reactivity.
Sustainable and cheaper intercession coupled with green technologies could be the feasible and finest approach for addressing the solicitous snags like energy crises, greenhouse gas emissions and fossil fuel depletions globally. Biodiesel appeared as a feasible substitute to achieve net zero emissions globally. Biodiesel produced from waste, toxic and non-edible oil seeds is clean, cheaper and capable for producing greener energy which ultimately contributed positively in boosting bio-economy (close circular economy). In the present study, the potential of Carthamus lanatus L. seed oil (CSO) as novel, non-edible and waste feedstock was investigated for producing biodiesel using cobalt tungstate loaded reduced graphene oxide (CoWO3@rGO) as novel, green and recyclable catalysts. The catalyst (CoWO3@rGO) was synthesized via Hummers method followed by characterizations by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and energy dispersive X-ray analysis (EDX). Optimize biodiesel yield (99.7 wt%) was achieved with optimum reaction conditions of 0.8 wt% catalyst, oil to methanol molar ratio of 1:12 and temperature 65 °C for 2 h reaction time. The optimized Carthamus lanatus L. biodiesel (CBD) yield was also predicted by drawing 3D surface plots with response surface methodology (Box-Behnken design). The synthesized CBD was also characterized using latest techniques of nuclear magnetic resonance (NMR) (1H and 13C), Gas Chromatography/Mass spectroscopy (GC–MS) and FT-IR. The green nanocomposite exhibits excellent reusability of seven times without significant drop in its reactivity during transesterification process. Fuel properties of fatty acid methyl ester complied with biodiesel international standards EN 14214, China GB/T 20828–2007 and ASTM D 6751. Ultimately, biodiesel produced from wild, uncultivated and non-edible CSO can be commendably used to engender and adopt a greener and sustainable energy approach. The acceptance and adoption of the green energy approach could bring positive outcomes in the environment which ultimately create healthier societal and economic development.
Research into biodiesel as a greener fuel alternative derived from renewable resources has been increased due to the depletion of fossil-fuel reserves, as well as growing environmental concerns. It ...is a cleaner alternative fuel that may be utilised in diesel engines without requiring any modifications to the engine. This document provides a synopsis of key research on the engine performance and exhaust emission characteristics of diesel engines that are fuelled with biodiesel blends, as well as the results of those investigations. Based on the engine performance tests, biodiesel blends exhibited greater brake specific fuel consumption and exhaust gas temperature than diesel fuel, but poorer braking power, torque, and thermal efficiency. When comparing engine emissions from biodiesel blends to diesel fuel, it was found that carbon dioxide and nitrogen oxides were greater, but that carbon monoxide was surprisingly lower. The most significant advantage of biodiesel is that it is carbon neutral and does not contribute to the emission of greenhouse gases. It contributes to a reduction in pollution by minimising the release of dangerous and hazardous compounds into the atmosphere, as well as significantly improving the performance of the engine.
Physical and chemical properties of biodiesel are influenced by the structural features of fatty acid, such as with saturated, monounsaturated and polyunsaturated fatty acids. In this study, seven ...non-edible oils have been selected, which include waste cooking oil derived palm olein,
Calophyllum inophyllum
, jatropha oil, castor oil, rubber seed oil, kapok seed oil and karanja oil. The critical parameters, e.g. cetane number (CN), iodine value (IV) and oxidation stability (OS) of biodiesel were correlated with the degree of unsaturated (DU) fatty acid, whereas the cold filter plugging point (CFPP) was correlated with the long chain saturated factor (LCSF). To meet the minimum EU requirement of EN 14214 of the critical parameter, the DU value of the CN was ≤133.5, IV ≤123.2 and OS ≤98.9. The LCSF values satisfied the Spanish regional standard—RD 61/2006 in summer (0 °C) at ≤8.4 and winter (−10 °C) at ≤0.1 of the CFPP. Based on the composition of the saturated, monounsaturated and polyunsaturated fatty acids, a triangular chart for the biodiesel property prediction was developed. This can then be used as a reference for non-edible oils.
•Pistacia khinjuk oil is novel non-edible oil for methyl ester production.•Maximum 88wt.% yield was attained in presence of heterogeneous catalyst.•About 3.0 fold shorter reaction time using UC than ...MS.•About 3.2 fold higher constant rate using UC compared to MS.•Activation energy was found to be 44.7kJ/mol.
Synthesis of biodiesel from a non-edible source as Pistacia khinjuk seed oil via ultrasonic cavitation (UC) system is reported in this study. A heterogeneous catalyst sulphated tin oxide impregnated with silicon dioxide (SO42-/SnO2–SiO2) was employed during the transesterification reaction in an UC reactor. Parametric optimisation results revealed the maximum Pistacia khinjuk methyl ester (PiKME) yield was 88wt.% at reaction time of 50min, amplitude of 50%, catalyst amount of 3.5wt.% and molar ratio of 13:1 (alcohol:oil). Performance of UC at optimised values was compared with mechanical stirring (MS). UC proved advantageous over MS with 3 times more time efficient. Hence, the superiority of UC over MS was established. About 3.2 fold higher reaction rate constant using UC (0.029min−1) compared to MS (0.009min−1). PiKME production via UC can potentially subsidise the overall cost of production by having 3.2 fold higher reaction rate constant than MS. PiKME met most of the fuel properties enlisted in EN14214 and ASTM D6751 standards.
This paper conceptualises a framework that examines the moderating effect of sustainability reporting practices on the relationship between enterprise risk management (ERM) implementation and ...business performance. Business performance is proxied through a value-added measurement technique, namely the economic value added (EVA). An Effective ERM adoption has a significant positive impact on businesses' overall performance. However, there are limited studies conducted on ERM implementation and how sustainability reporting could influence organisations' performance through ERM. Many business organisations globally do not incorporate sustainability initiatives within their corporate strategy, whereas they should be critical input for strategic management and corporate planning. By combining the Stakeholders Theory and the Modern Portfolio Theory, this study integrates ERM implementation with sustainability reporting to examine their effect on business performance's economic value added. This paper proposes a quantitative content analysis of the of the annual reports to obtain information about companies' enterprise risk management practices and sustainability reporting. While secondary data related to the economic value added (EVA) measurement will be extracted from Thomson Reuters DataStream. The paper proposes ordinary least square (OLS) for the proposed analysis. The conceptual model espoused by this study will provide insights in formulating strategies and serve as an important conduit to enhance the EVA performance especially of the oil and gas companies. The EVA performance can be achieved through the improvement of price to earnings ratios and the reduction of cost of capital by reducing information asymmetry among the business, the insurance companies, the lenders and the shareholders of the company.
•Moderating effect of sustainability examined by conceptual framework.•ERM implementation and business performance measured through economic value added analysis.•Petroleum companies can put in place ERM framework, to attain cleaner and sustainable operations.•Sustainability reporting as a moderator between ERM implementation and business performance relationship.
