Biodiesel by-product

Shrivastav and co-workers [26] attempted to isolate PHA-producing bacteria from soil and marine environments using a Jatropha biodiesel by-product generated from the biodiesel production process which uses Jatropha curcas seeds as the carbon source. The Nile red... 

Duarte and Maugeri (2014) studied lipid production by Candida sp. LEB-M3 cultivated in pure and raw glycerol. The feasibility of biodiesel production by the yeast Candida sp. LEB-M3 was indicated by predicting FAME properties for pure and raw glycerol respectively, including cetane number (56—53), heat of combustion (37—39 kJ/g), oxidative stability (8.58 h), kinematic viscosity (3.82—3.79 mm /s), density (807—872 kg/m ), and iodine index (74—115.5 gE/lOOg). Leiva-Candia et al. (2015) estimated biodiesel properties produced from SCO derived from Rhodosporidium toruloides, Lipomyces starkey, and Cryptococcus curvatus cultivated on biodiesel by-product streams. More specifically, cetane number (62.39—69.74), lower calorific value (37,393.49—37,561.68 kJ/kg), cold-filter plugging point (4.29—9.58°C), flash point (158.73—170.34°C), and kinematic viscosity (4.6—34.87 mm /sat 40°C) were determined. 

Kiran, E.U., Trzeinski, A., Webb, C., 2013. Microbial oil produced from biodiesel by-products could enhance overall production. Bioresource Technology 129, 650—654. 

Xu, J.Y., Zhao, X.B., Wang, W.C., Du, W., Liu, D.H., 2012. Microbial conversion of biodiesel by-product glycerol to triacylglycerols by oleaginous yeast Rhodosporidium toruloides and the individual effect of some impurities on lipid production. Biochemical Engineering Journal 65, 30—36. 

During the last decade many industrial processes shifted towards using solid acid catalysts (6). In contrast to liquid acids that possess well-defined acid properties, solid acids contain a variety of acid sites (7). Sohd acids are easily separated from the biodiesel product they need less equipment maintenance and form no polluting by-products. Therefore, to solve the problems associated with liquid catalysts, we propose their replacement with solid acids and develop a sustainable esterification process based on catalytic reactive distillation (8). The alternative of using solid acid catalysts in a reactive distillation process reduces the energy consumption and manufacturing pollution (i.e., less separation steps, no waste/salt streams). 

Moreover, the catalytic results clearly show that the lipase immobilization procedure strongly influences the final activity of the enzyme. Adsorption and entrapping procedures allow to preserve the open and active conformation of the enzyme whit respect to electrostatic ones. Using the entrapped lipase, the enzyme leaching can be avoided and the biodiesel total productivity strongly increases if compared with the one obtained by the free enzyme. 

Biodiesel (fatty acid methyl ester (FAME)) production is based on transesterification of vegetable oils and fats through the addition of methanol (or other alcohols) and a catalyst, giving glycerol as a by-product (which can be used for cosmetics, medicines and food). Oil-seed crops include rapeseeds, sunflower seeds, soy beans and palm oil seeds, from which the oil is extracted chemically or mechanically. Biodiesel can be used in 5%-20% blends with conventional diesel, or even in pure form, which requires slight modifications in the vehicle. 

Table 9.3 Energy values, costs and emissions per hectare in the comparison of the production of biodiesel by oilseed rape and bioethanol by wheat crops. (Adapted from [4]).

Biodiesel is a mixture of methyl esters of fatty acids and is produced from vegetable oils by transesterification with methanol (Fig. 10.1). For every three moles of methyl esters one mole of glycerol is produced as a by-product, which is roughly 10 wt.% of the total product. Transesterification is usually catalyzed with base catalysts but there are also processes with acid catalysts. The base catalysts are the hydroxides and alkoxides of alkaline and alkaline earth metals. The acid catalysts are hydrochloride, sulfuric or sulfonic acid. Some metal-based catalysts can also be exploited, such as titanium alcoholates or oxides of tin, magnesium and zinc. All these catalyst acts as homogeneous catalysts and need to be removed from the product [16, 17]. The advantages of biodiesel as fuel are transportability, heat content (80% of diesel fuel), ready availability and renewability. The... 

Glycerol as a by-product from biodiesel production can be considered as a green chemical feedstock for subsequent catalytic transformation. In contrast to traditional petrochemical feedstocks, the present one is highly functionalized, its transformation requiring selective defunctionalization. 

In conclusion, the economically competitive, non-subsidized production of liquid biofuels requires (a) the use cheaper and more reliable sources of renewable raw material (b) efficient conversion, with minimum waste, of cellulosic, fiber or wood-based, waste biomass into fermentable sugars (c) significantly improved efficiency of the production processes and (d) use by-products (e.g., glycerol in biodiesel production). Several of these aspects are discussed in details in various chapters. 

The term energy crop can be used both for biomass crops that simply provide high output of biomass per hectare for low inputs, and for those that provide specific products that can be converted into other biofuels such as sugar or starch for bioethanol by fermentation, or into vegetable oil for biodiesel by transesterificatiou... 

Stepwise degradation of sugars under catalytic conditions leads to shorter-chain sugars and such by-products as CO, C02, and H20 depending on the conditions (see also next section).348 Sucrose or other carbohydrates have been used for the preparation of new solid acidic catalysts by partial carbonization followed by sulfonation. This leads to sheets of amorphous carbon bearing hydroxyl, carboxyl, and sulfonic groups. These have been used for the production of biodiesel fuel.349... 

Therefore, the purpose of the present work was to study an alternative method for biodiesel fuel production that has a lower reaction condition than the one-step supercritical methanol method, through the two-step preparation consisting of hydrolysis of triglycerides in subcritical water and subsequent methyl esterification of the fatty acids by supercritical methanol treatment. In this article, we present various parameters affecting the yield of fatty acids in hydrolysis from triglycerides followed by methyl esterification of the fatty acids. We also compare the one- and two-step preparation methods and propose a production scheme of the latter. 

We have developed a catalyst-free method of biodiesel fuel production by supercritical methanol (10-12), and we found that the process becomes much simpler and that the yield of biodiesel is higher compared with the alkaline-catalyzed method. The aim of the present work was, therefore, to investigate the possibilities of biodiesel fuel production from rapeseed oil with various alcohols by supercritical treatment. In addition, the super-critically prepared biodiesel fuel was studied for its cold properties. 

---