Category Archives: Biofuels and Bioenergy

Hexane Solvent Method

Hexane solvent extraction has long been used effectively for vegetable oil extrac­tion. A very good example is in the production of soybean oil, for which hex­ane solvent extraction is predominantly used in industrial production due to its lower energy consumption and higher extraction efficiency (oil yield) in comparison to hydraulic presses, that is, the expeller method. Furthermore, hexane extraction technology […]

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Xylose Fermentation

Inasmuch as xylose accounts for 30-60% of the fermentable sugars in hard­wood and herbaceous biomass, the fermentation of xylose to ethanol becomes an important issue. The efficient fermentation of xylose and other hemicel- lulose constituents is essential for the development of an economically viable process to produce ethanol from lignocellulosic biomass. Needless to say, co-fermentation of both glucose and xylose […]

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Gasification

Unlike combustion, gasification is carried out with less than a stoichiomet­ric amount of required oxygen such that only partial oxidation of waste materials occurs. Gasification generates a producer gas of low, medium, or high BTU content depending on the operating conditions and amount of oxygen. The gasification temperature varies from 500°C to about 1,800°C depending upon the desired gas composition […]

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Environment and Ecology

Sound management and efficient utilization of biomass can provide sub­stantial benefits in terms of increased biodiversity, local amenity, and even rehabilitation of land and water courses [13]. Examples include income-gen­erating management of native woodlands, growing energy crops such as short rotation coppice (SRC) that has biodiversity and soil conservation ben­efits, utilization of low-fertility and abandoned lands, returns and increase of […]

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Cold Flow Properties

Pure biodiesel (B100) has poor cold-temperature properties as straight die­sel fuel. Biodiesel’s cloud point (CP) and cold filter plugging point (CFPP) are both high, thus making pure biodiesel (B100) unsuitable as a cold-climate fuel without blending or additives. When biodiesel is cooled below a certain temperature, some ingredient molecules of biodiesel start to aggregate and form crystals. This temperature varies […]

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Fermentation of Sugars

A widely used form of sugar for ethanol fermentation is blackstrap molasses, which contains about 30-40 wt% sucrose, 15-20 wt% invert sugars such as glucose and fructose, and 28-35 wt% of nonsugar solids. The direct fermenta­tion of sugarcane juice, sugarbeet juice, beet molasses, fresh and dried fruits, sorghum, whey, and skimmed milk have been considered, but none of these could […]

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Thermochemical Conversion of Biomass

Thermochemical treatment of biomass can convert biomass into solid, liquid, and gaseous fuel products whose compositional distribution is governed by the imposed process treatment conditions. The solid product is usually char (or biochar), the liquid product is bio-oil, and the gaseous product is biosyn­gas. The process also involves formation of the unwanted product of tar. The thermochemical conversion process involves […]

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Transesterification

Transesterification is the reaction of triglycerides (or other esters) with alco­hols to produce alkyl esters (biodiesel) and glycerol, typically in the presence of acid and base catalysts (see Figure 6.10). Triglycerides are one of the three types of biomass obtained in 350 types of crops such as soybean, cotton seed, rapeseed, and algae, among others, as well as in fatty […]

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Microalgae and Growth

Microalgae or microphytes are a division of algal organisms encompassing diatoms, the green algae, and the golden algae. These microscopic organisms are incredibly efficient solar energy converters that perform photosynthe­sis and are capable of rapid growth in either freshwater or saline environ­ments. Although this value varies from species to species and depends upon cultivation conditions, roughly 50% of the weight […]

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