https://www.cti2000.it/Bionett/BioD-1999-101%20Biodiesel%20production%20review.pdf

Biodiesel production : a review

A review on biodiesel production using catalyzed transesterification

Biodiesel fuel production by transesterification of oils.

Efforts are under way in many countries, including India, to search for suitable alternative diesel fuels that are environment friendly. The need to search for these fuels arises mainly from the standpoint of preserving the global environment and the concern about long-term supplies of conventional hydrocarbon-based diesel fuels. Among the different possible sources, diesel fuels derived from triglycerides (vegetable oils/animal fats) present a promising alternative to substitute diesel fuels. Although triglycerides can fuel diesel engines, their high viscosities, low volatilities and poor cold flow properties have led to the investigation of various derivatives. Fatty acid methyl esters, known as biodiesel, derived from triglycerides by transesterification with methanol have received the most attention. The main advantages of using biodiesel are its renewability, better-quality exhaust gas emissions, its biodegradability and given that all the organic carbon present is photosynthetic in origin, it does not contribute to a rise in the level of carbon dioxide in the atmosphere and consequently to the greenhouse effect.

Triglycerides-based diesel fuels

The world is confronted with the twin crises of fossil fuel depletion and environmental degradation. The indiscriminate extraction and consumption of fossil fuels have led to a reduction in petroleum reserves. Petroleum based fuels are obtained from limited reserves. These finite reserves are highly concentrated in certain region of the world. Therefore, those countries not having these resources are facing a foreign exchange crisis, mainly due to the import of crude petroleum oil. Hence it is necessary to look for alternative fuels, which can be produced from materials available within the country. Although vegetative oils can be fuel for diesel engines, but their high viscosities, low volatilities and poor cold flow properties have led to the investigation of its various derivatives. Among the different possible sources, fatty acid methyl esters, known as Biodiesel fuel derived from triglycerides (vegetable oil and animal fates) by transesterification with methanol, present the promising alternative substitute to diesel fuels and have received the most attention now a day. The main advantages of using Biodiesel are its renewability, better quality exhaust gas emission, its biodegradability and the organic carbon present in it is photosynthetic in origin. It does not contribute to a rise in the level of carbon dioxide in the atmosphere and consequently to the green house effect. This paper reviews the source of production and characterization of vegetable oils and their methyl ester as the substitute of the petroleum fuel and future possibilities of Biodiesel production.

Biodiesel production through the use of different sources and characterization of oils and their esters as the substitute of diesel: A review

Preparation and properties of diesel fuels from vegetable oils

Vegetable oils have heat contents approximately 90% that of diesel fuel and are potential alternate fuel candidates. A major obstacle deterring their use in the direct-injection diesel engine is their inherent high viscosities which are nearly 10 times that of diesel fuel. Solution to the viscosity problem has been approached in three ways: 1) microemulsification, 2) pyrolysis, and 3) transesterification. Microemulsification with short chain alcohols such as methanol and ethanol yields fuels that are clear, thermodynamically stable liquid systems with viscosities near the ASTM specified range for number2 diesel fuel. These micellar systems may be formulated ionically or nonionically. The alcohols are attractive from an economic as well as a renewable resource viewpoint. Methanol has an economic advantage over ethanol, and it can be derived from a large variety of base stocks. These include biomass, municipal waste, natural gas being flared at refineries and from coal. Pyrolysis of vegetable oils is another approach to lowering their viscosity. Soybean and safflower oils were thermally decomposed in both air and nitrogen to obtain fuels for the diesel engine. Using standard ASTM distillation conditions, yields of pyrolysis products were about 75%. GS-MS analysis of the distillates showed the presence of alkanes, alkenes, aromatics,more » and carboxylic acids with carbon numbers ranging from 4 to more than 20. Fuel properties of the thermal decomposition products were substantially improved as evaluated by lower viscosities and higher cetane numbers compared to the unpyrrolyzed vegetable oils. Simple esters from transesterification of vegetable oils perform well in engine tests, and thus show good promise as an alternative or emergency fuel for diesel engines.« less

B. Freedman

Papers

Preparation and properties of diesel fuels from vegetable oils

Diesel fuels from vegetable oils