توصيفگر ها :
سوخت هاي زيستي , اتانول , بيوگاز , بيوديزل , ضايعات بلوط
چكيده انگليسي :
While the energy market demand is increasing, the main energy resource is still fossil fuels. The problem is that not just their byproducts are extremely toxic, which have created so much environmental damage and costs, such as pollution, as well as many excruciating diseases, such as cancer, respiratory problems, autoimmune diseases, fetus malformation and neurodegenerative disease, their resources are limited too, and sooner or later we are going to hit the bottom, that's it no more petroleum. On the other hand, biofuels could use a much diverse, locally available, and cheaper raw material, and on top of that, they can be locally and instantly produced and at the same time, require much smaller initial capital compared to other renewable enegy resources. As a result, these promising renewable energy resources not only can easily and must but also will certainly replace fossil fuels. There is one problem, despite their diverse source, they still have a limitation in their supply quantity, since some of them have alimentary value. Therefore, we need to shift to alternative resources that use wastes rather than foods. In this regard, using acorn wastes as a cheap and abundant raw material in Iran seems to be a good soloution. In this study, acorn wastes were used separately as feedstocks of processes are transformed into bioethanol, biodiesel, and biogas; also due to separate hydrolysis and fermentation process(SHF), the enzymatic hydrolysis stage wastes were used to produce biogas. Acorn kernel contains considerable starch and oil, and leaves, branches, twigs, trunk, bark, cup, and fruit shells contain considerable lignocellulosic cmpounds, so the whole processes were classified into two categories: the ones done on lignocellulose derivatives and the others were starch compounds. However, tannins and phenol-based compounds inhibit yeast Saccharomyces cerevisiae fermentation process therefore we tried Mucor indicus as well and we compared the results. It became obvious that in order to increase the ethanol yield, we needed to pretreat lignocellulosic compounds in order to separate lignin from. Pretreatment increased the ethanol production efficiency of almost all lignocellulosic substrates and the highest ethanol production efficiency was 63% w/w of pretreated leaves fermented by Mucor Indicus. Pretreatments significantly reduced phenolic and tannin compounds in the starchy substrate, increased ethanol production, but did not increase ethanol production efficiency. The maximum concentration of ethanol produced from acorn kernel was 18.1 g/l after extraction with ethanol and fermentation by Mucor Indicus. In biogas production, the highest biomethane yield was obtained from anaerobic digestion of hydrolyzed wastes, and the pretreatment of lignocellulosic substrates did not have a positive effect on biomethane yield. Biomethane produced from starchy substrates was significantly higher than lignocellulosic substrates and the highest yield was measured at 483.3.3 ml/g VS from hydrolysis waste of raw acorn kernel. Acorn oil extracted with hexane solvent was used to produce biodiesel with a yield of 78.2%w/w, which was of good quality according to ASTM standards. To understand the ability to convert acorn wastes to biofuels, the amount of gained energy from total acorn wastes in terms of liters of gasoline, was calculated according to two different scenarios of 304.2 and 182.7 liters. In general, according to the results, all components of oak wastes are suitable for the production of biofuels.
