In Situ Preparation Of FAEE And FAME From Low Quality Rice Bran And The Integrated Utilization Design Of Rice Bran

Under the pressure of energy and environment crisis, finding renewable environmentally friendly energy is becoming a great trend of the world. In this situation, bioengery such as fatty acid methyl ester (FAME) and fatty acid ethyl ester (FAEE) has attracted a lot of attention. FAME and FAEE have similar molecular structure and combustibility with the fossil diesel oil. They are typical renewable environmentally friendly energy, and usually called biodiesel. Besides, they could also be used as substitute of some traditional toxic organic solvent, because they have good solubility and resolvability. However, with the development of biodiesel industry, the problem of raw material has become a major constraint to the further development of this industry. Because the cost of the oil-containing material takes more than 70% cost of the biodiesel product, a lot of researches focus on the cheap raw materials. In another aspect, China produces more than 10,000,000 tons of rice bran annually and most of the rice bran is utilized unreasonably. As realized the problems of these two areas, we used low quality rice bran to produce FAME and FAEE in this dissertation, which is killing two birds with one stone. Based on the research, we made integrated strategies of rice bran utilization, too.Firstly, we need to design a process which could produce FAME and FAEE from low quality feedstock oil. Traditionally, the typical method using low quality oil to produce FAME and FAEE is two-step process. The first step is an acid catalyzed process, which esterifies free fatty acids (FFAs), and the second step is an alkaline catalyzed process, which transesterifies the glycerides in the feedstock. However, the intermediate treatment process between esterification and transesterificaion processes is a tedious procedure including neutralization of acid catalyst, removal of water and impurities, evaporation of alcohol or settlement for phase-separation, et al. The tedious work not only wastes a lot of time, but also produces waste water which is unfriendly to the environment. In our work, we evolved a simple route for the production of FAME and FAEE, by using the mixture of soybean oil and oleic acid (OA) as feedstock to imitate low quality lipids with substantial FFAs content. The merit of our route is that the intermediate process could be eliminated based on our designed experimental apparatus, thus acid and alkaline catalyzed processes performed without intervals. The water in the reaction system was eliminated simultaneously when it was formed by introduction of CaO powder to Soxhlet apparatus. On considering the environmental character of the whole strategy, the waste water and CaO residue were used as raw materials to produce value-added nano-CaCO3 byproduct via carbonation method at room temperature. Based on our strategy, the production process of FAME and FAEE could be simplified and the production cost could be reduced. It was an economical route for FAME and FAEE production.Secondly, based on the designed process, we studied the production of FAEE from low quality rice bran. The effects of solvent, acid and alkaline catalysts on the yield rate, esterification rate and transesterification rate were studied. 12.29% ( w FAEE / wrice?bran) of FAEE was obtained when absolute ethanol was used as solvent to extract rice bran oil. The esterification rate and transesterification rate reached 97.90 % and 82.78 %, respectively. With the aid of petroleum ether, the yield rate of FAEE could be improved to 15.50% ( w FAEE / wrice?bran), and the esterification rate and transesterification rate reached 98.89% and 85.94%. Moreover, we found that the petroleum ether could restrain saponification in the case of FAEE production.Thirdly, we further studied the production of FAME from low quality rice bran. The oil extraction process and the effect of petroleum ether on the esterification and transesterification processes were investigated. Besides, the moister resistance of the system was investigated, too. The results approved that the designed process was feasible. It was different from FAEE that we found there was a synergistic effect between methanol and petroleum ether. Less methanol and acid catalyst could be used because of this effect. When 50 g of rice bran, 75 mL of absolute methanol, 150 mL of petroleum ether, 0.75 g of concentrated sulfuric acid and 0.71 g of sodium hydroxyl were used, 16.69% ( w FAME / wrice?bran) of FAME was obtained. The esterification rate and the transesterification rate reached 98.83% and 80.47%.Finaly, on considering the environmental character of the whole strategy, we investigated the utilization of the waste water and CaO residue from FAME and FAEE production. In this chapter, value-added calcium carbonate (CaCO3) with micro/nanostructures was produced via carbonation method at ambient temperature. The results showed that the CaCO3 obtained was hydrophobic (contact angle, 111o) and had broccoli-like morphology. It was made up of many uniform nano-rods, and each rod was composed of smaller particles with diameters about 50 nm. The idea of wastes utilization could make the FAME/FAEE production process environmentally friendly, and the income of the produced CaCO3 could further compensate the cost of FAME/FAEE production.The integrated utilization of rice bran is a promising project. As a result, at the end of the dissertation, we designed some technical flows for the further investigation of rice bran and hope it would be useful for the coming works.