Study On Fish Oil Extraction From Grass Carp Viscera And The Biodiesel Production

In this paper, the extraction of fish oil from grass carp viscera by diluted alkalihydrolysis was studied. The optimal level of each factor under our experiment conditionwas obtained through single factor experiment: hydrolysis temperature,55℃; hydrolysistime,60min; the amount of KCl,3%; the salt time,15min.The extraction of fish oil from grass carp viscera by solvent water phase ofenzymatic hydrolysis was also explored in this paper. With the fish oil extractionefficiency as the index of investigation, the fish oil extraction techniques optimizedthrough single factor and orthogonal experiment. The results show that the oil extractionefficiency can reach up to88.23%when the pH was3.5, the amount of acid protease was2%, the ratio of water to material was2:1, the enzymolysis time was4h, the enzymolysistemperature was40℃.The fatty acid composition of grass carp oil and rap seed oil were analyzed anddetected by GC/MS. The content of saturated fatty acid and unsaturated fatty acid was21.89%and76.92%respectively in grass carp oil. The content of saturated fatty acid inrape seed oil was14.84%, which was lower than that of fish oil; the content ofunsaturated fatty acid in rape seed oil was84.34%, which was higher than that of fish oil.The paper studies the biodiesel prepared technology of rape seed oil and grass carpoil. The rape seed oil was used to produce biodiesel, and the result provides a guide forthe research of fish oil biodiesel production. With the rape seed oil to produce biodiesel,the optimal technological process was obtained by single factor experiment andorthogonal design experiment: molar ratio of methanol to oil,7:1; amount of NaOH,1.2%; reaction temperature,45℃; reaction time,45minutes. NaOH catalysted processwas adopted to prepare biodiesel from low acid grass carp oil, the optimal technologycondition was obtained by single factor experiment and orthogonal design experiment:molar ratio of methanol to oil,7:1; amount of NaOH,1.4%; reaction time,50minutes;reaction temperature,50℃. The solid super base was adopted to prepare biodieselfromlow acid grass carp oil through single factor experiment: catalyst amount,2%; reactiontime,2h; molar ratio of methanol to oil,12:1; reaction temperature,65℃, the conversionwas93.30%. With the high acid fish oil to produce biodiesel through single factor experment: catalyst amount,11%; reaction time,4h; molar ratio of methanol to oil,12:1;reaction temperature,50℃.The molecular structure, fatty acid composition and part of important physicalchemistry index of fish oil biodiesel were analyzed and detected in this study. Thecharacteristic absorption peak of fish oil and its biodiesel is determined by IR, and theirmolecular structure has been initiated; the fatty acid composition of fish oil biodiesel isdetermined by GC/MS, the palmitic acid methyl ester (C16:0) and oleic acid methyl ester(C18:1) were the two main components, as can we see from the chemical composition.The content of saturated fatty acid methyl ester and unsaturated fatty acid methyl esterwas23.19%and67.52%respectively. Part of the important fuel properties, such as acidvalue, specific gravity, kinematic viscosity, and so on, were determined and basically inline with the standard of Chinese biodiesel.