Fast pyrolysis utilizes biomass to produce a product that is used both as an energy source and a feedstock for chemical production. Considerable efforts have been made to convert wood biomass to liquid fuels and chemicals since the oil crisis in mid-1970s. This review focuses on the recent developments in the wood pyrolysis and reports the characteristics of the resulting bio-oils, which are the main products of fast wood pyrolysis. Virtually any form of biomass can be considered for fast pyrolysis. Most work has been performed on wood, because of its consistency and comparability between tests. However, nearly 100 types of biomass have been tested, ranging from agricultural wastes such as straw, olive pits, and nut shells to energy crops such as miscanthus and sorghum. Forestry wastes such as bark and thinnings and other solid wastes, including sewage sludge and leather wastes, have also been studied. In this review, the main (although not exclusive) emphasis has been given to wood. The literature on woo...

Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review

Progress and recent trends in biodiesel fuels

Influence of fatty acid composition of raw materials on biodiesel properties.

Biodiesel production from heterotrophic microalgal oil.

Biofuels demand is unquestionable in order to reduce gaseous emissions (fossil CO2, nitrogen and sulfur oxides) and their purported greenhouse, climatic changes and global warming effects, to face the frequent oil supply crises, as a way to help non-fossil fuel producer countries to reduce energy dependence, contributing to security of supply, promoting environmental sustainability and meeting the EU target of at least of 10% biofuels in the transport sector by 2020. Biodiesel is usually produced from oleaginous crops, such as rapeseed, soybean, sunflower and palm. However, the use of microalgae can be a suitable alternative feedstock for next generation biofuels because certain species contain high amounts of oil, which could be extracted, processed and refined into transportation fuels, using currently available technology; they have fast growth rate, permit the use of non-arable land and non-potable water, use far less water and do not displace food crops cultures; their production is not seasonal and they can be harvested daily. The screening of microalgae (Chlorella vulgaris, Spirulina
 maxima, Nannochloropsis sp., Neochloris oleabundans, Scenedesmus obliquus and Dunaliella tertiolecta) was done in order to choose the best one(s), in terms of quantity and quality as oil source for biofuel production. Neochloris oleabundans (fresh water microalga) and Nannochloropsis sp. (marine microalga) proved to be suitable as raw materials for biofuel production, due to their high oil content (29.0 and 28.7%, respectively). Both microalgae, when grown under nitrogen shortage, show a great increase (~50%) in oil quantity. If the purpose is to produce biodiesel only from one species, Scenedesmus obliquus presents the most adequate fatty acid profile, namely in terms of linolenic and other polyunsaturated fatty acids. However, the microalgae Neochloris oleabundans, Nannochloropsis sp. and Dunaliella tertiolecta can also be used if associated with other microalgal oils and/or vegetable oils.

Microalgae as a raw material for biofuels production

Preparation and characterization of bio-diesels from various bio-oils.

Methods for recovery of concentrates of lubricating compounds and biologically active compounds from vegetable and animal oils, fats and greases that allow separation of triglycerides, from components with higher lubricity or biological activity or enrichment protocols that increase the concentration of high lubricity or biologically active compounds in the triglyceride. The triglycerides are transesterified with a lower alcohol to produce alkyl esters. Following the conversion process the esters are separated from high molecular weight high lubricity compounds and biologically active compounds by distillation. The esters have some lubricity and may be sold as pollution reducing fuel components. The high boiling point compounds that are the residues of distillation, however, can either contribute significant lubricity and may be used widely in lubricant applications or added to petroleum fuels to decrease friction or the biologically active components may be used in nutritional, cosmetic and therapeutic applications. Therapeutic applications include use in human diets to lower cholesterol.

Methods for concentration and extraction of lubricity compounds and biologically active fractions from naturally derived fats, oils and greases

Various vegetable-oil derived esters using methyl, ethyl, butyl, and 2-propyl alcohols were prepared and tested as diesel fuel lubricity additives in a roller-on-cylinder lubricity evaluator. At1% additive treat rate, the canola methyl and 2-propyl esters, the best-performing esters, increased the lubricity number of a reference fuel by 60%. Statistical analyses indicated strong effects of fatty acids and alcohols on the wear, friction, and lubricity number of the fuel. While no single fatty acid was identifiably responsible for the wear reduction, certain non-linoleic compounds correlated with the wear data in a semi-log relationship. The low-temperature behaviour of the biodiesel was studied using differential scanning calorimetry. The major transitional peak temperature of the biodiesel esters changed with the melting points of their primary fatty acids, and decreased with the lengthening and branching of the tail alkyl groups.

Phillip Barry Hertz

Papers

Preparation and characterization of bio-diesels from various bio-oils.

Methods for concentration and extraction of lubricity compounds and biologically active fractions from naturally derived fats, oils and greases

Preparation and evaluation of vegetable oil derived biodiesel esters as lubricity additives