• Energy Research
• 6. Clean water close
• 12. Responsible consumption close

Background of the Problem: In the context of depletion of fossil fuels, ever increasing pollution levels with fossil fuels and increasing economic burden on developing countries like India, the search for alternative fuels has become pertinent. Vegetable oils are important substitutes for diesel fuel, as they are renewable and have properties comparable to diesel fuel. However, drawbacks associated with vegetable oils are high viscosity and low volatility compel to use low heat rejection diesel engines. The viscosity of vegetable oils is reduced to some extent by the process of esterification, known as biodiesel. The exhaust emissions of diesel engines cause health hazards if they are inhaled in. They also cause environmental disorders like global warming, acid rain and Green-house effect. Hence the study of exhaust emissions is an important and urgent task. Aim: Experiments were conducted to determine the exhaust emissions of a low heat rejection (LHR) diesel engine consisting of ceramic coated cylinder head with different operating conditions of crude jatropha oil (CJO) and its biodiesel of normal temperature and preheated temperature with varied injection timing and injection pressure. Study Design: Exhaust emissions of particulate emissions and oxides of nitrogen (NOx) were determined at various values of brake mean effective pressure (BMEP) with different versions of the engine, with varied injection timing and injection pressure with different operating conditions of jatropha oil in crude form and biodiesel. Methodology: Exhaust emissions were determined with sophisticated analyzers at various values of BMEP of the engine. Results: Conventional engine (CE) showed increased pollutants, while LHR engine showed reduction of particulate emissions and drastically increased nitrogen oxide (NOx) levels with both forms of the test fuels at recommended injection timing and pressure. The performance of both versions of the engine improved with advanced injection timing and higher injection pressure when compared with CE with neat diesel operation. Advanced injection timing and increased injection pressure and preheated test fuels reduced pollutants. Biodiesel operation further decreased particulate emissions and increased nitrogen oxide (NOx) emissions.

Abstract The extraction of Biodiesel from vegetable oil is time-consuming and requires human involvement to perform and keep track of chemical titration, stirring, and washing the product for each batch of production. A well-designed system can significantly eliminate human interaction and expedite the whole process. The construction of an inexpensive automated biodiesel plant can help produce Biodiesel on a large scale and make a breakthrough in Bangladesh’s economy as no such effort has been undertaken so far. To achieve the desired aim, this paper focuses on implementing the construction of a cheap, compact, and automatic system that will exhaustively reduce human interactions and the processing time and increase biodiesel yield. For this purpose, an automated biodiesel processor was designed and constructed in conjunction with pumps, solenoid valves, level sensors, temperature sensors, etc., using a programmable logic controller (PLC). Upon completing a full cycle, the plant delivers certified Biodiesel and the leftover by-products are collected for further recycling. Different batches of Biodiesel were produced. A comparative study of the physical properties of the fuel and the diesel engine’s performance characteristics by these fuel samples was analysed and showed satisfactory results.

AbstractBACKGROUND: Conventional biodiesel production relies on trans‐esterification of lipids extracted from vegetable crops. However, the use of valuable vegetable food stocks as raw material for biodiesel production makes it an unfeasibly expensive process. Used cooking oil is a finite resource and requires extra downstream processing, which affects the amount of biodiesel that can be produced and the economics of the process. Lipids extracted from microalgae are considered an alternative raw material for biodiesel production. This is primarily due to the fast growth rate of these species in a simple aquaculture environment. However, the dilute nature of microalgae culture puts a huge economic burden on the dewatering process especially on an industrial scale. This current study explores the performance and economic viability of chemical flocculation and tangential flow filtration (TFF) for the dewatering of Tetraselmis suecica microalgae culture.RESULT: Results show that TFF concentrates the microalgae feedstock up to 148 times by consuming 2.06 kWh m−3 of energy while flocculation consumes 14.81 kWh m−3 to concentrate the microalgae up to 357 times. Economic evaluation demonstrates that even though TFF has higher initial capital investment than polymer flocculation, the payback period for TFF at the upper extreme of microalgae revenue is ∼1.5 years while that of flocculation is ∼3 years.CONCLUSION: These results illustrate that improved dewatering levels can be achieved more economically by employing TFF. The performances of these two techniques are also compared with other dewatering techniques. Copyright © 2009 Society of Chemical Industry