Читать книгу Biodiesel Production - Группа авторов - Страница 16

All over the world, the usual lipid feedstocks for BD production are refined vegetable oils. In this group, the oil of choice varies with location according to availability; the most abundant lipid is generally the most common feedstock. The bases for this are not only the desire to have an ample supply of product fuel but also because of the inverse relation between supply and cost. Refined oils can be comparatively costly under the best of conditions, compared with petroleum products, and the choice of oil for BD production depends on local availability and corresponding affordability. The four oil crops clearly dominate the feedstock sources used for worldwide BD production. With a share of nearly 85%, rapeseed oil is by far leading the field, followed by sunflower seed oil, soybean oil, and palm oil [36]. Apart from the “great four” – rapeseed oil, sunflower seed oil, soybean oil, and palm oil in BD production – other edible plant oils have also successfully been transesterified to produce BD.

The choice of raw material used for BD production in a specific region mainly depends on the respective climatic conditions. Thus, rapeseed and sunflower oils are mainly used in the European Union [37], palm oil predominates in BD production in tropical countries [38, 39], and soybean oil [40] and animal fats are the major feedstocks in the United States. FA ester production has also been demonstrated from a variety of other feedstocks, including the oils of coconut [41], rice bran [42], Thespesia populnea [43], safflower [44], palm kernel [45], M. oleifera [46], Citrus reticulata (mandarin orange) [47], Jatropha curcas [48], Ethiopian mustard [13], Cynara cardunculus [49], Hibiscus esculentus [50], maize [51], Cyperus esculentus (Barminas et al. [52]), Prunus mahaleb [53], kapok [54], tobacco [55], milkweed [7], Yucca aloifolia [56], Oleum papaveris seminis [57], Pongamia [58], Brassica napus [59], Citrullus colocynthis [53], rubber seed oils [60], palm FA distillate [61], the animal fats, tallow [7, 62], lard [63], and waste oils [64, 65]. As such, any animal or plant lipid should be a ready substrate for the production of BD. Such features as supply, cost, storage properties, and engine performance will determine whether a particular potential feedstock is actually acceptable for commercial fuel production.

One way of reducing the production costs for BD fuels is the use of nonedible oils, which tend to be considerably cheaper than edible vegetable oils [66]. A number of plant oils contain substances that make them unsuitable for human consumption. In some cases, these substances can be removed by refining. For example, gossypol contained in cottonseeds can effectively be eliminated from the oil and the press cake to allow utilization as a cooking oil and animal feed, respectively [55]. Sometimes harmful ingredients can also be eliminated by breeding, as was the case with glucosinolates and erucic acid in rapeseed. In many cases, however, the removal of toxic components from the fatty material has not been accomplished or even attempted yet.