Study On Bio-diesel Preparation From Scrap Botanic Oil

A systemic experiment of preparation of bio-diesel from scrap botanic oil was carried out, in which rice bran oil was used as raw material. The main experiment included: the study of pretreatment, the optimal condition of pre-esterification, the preparation of CaO/MgO catalyzer and the activity of the catalyzed esterification.In the study of the pretreatment of raw oil, influences on dewaxing and dehydration of different process of degumming, such as hydration degumming, wet degumming and special degumming was researched, and the optimal condition of each process was ascertained. The degumming effect of hydration process, in which only about 90% of hydrating lecithoid was emerged, was the worst. Wet degumming can emerge part of the remnant undydrating lecithoid and it can make the content of phosphorus reduce to about 3mg/kg oil. The special degumming process was better than the other two processes. The content of H₂O can reduced to 0.05% at 85℃, 0.09MPa for 20min.Orthogonal experiments were taken out in order to the optimizing experiments of the pre-esterification of the pretreated rice bran oil. The order of influences for the effect of pre-esterification was the ratio of mellow to oil, the reaction time, the reaction temperature, the pace of whisking and the amount of the catalyzer. At the optimal condition, the acid value of the oil can reduce from 30mgKOH/g oil to 3.75mgKOH/g oil. Using the pre-esterification oil as raw material, in the condition of the ratio of mellow to oil of 6:1, the reaction temperature of 75℃and the reaction time of 2h, the production after decompress distillation was analyzed by GC/MS, and the content of polymethylmethacrylate was about 92%, except the acid value, other main guide lines can reach or exceed the value of national standard. The preparation of solid alkali CaO/MgO was studied systemically. XRD and SEM were used in the characterization of the solid catalyzer. The result showed that the diameter of particles was below 2μm. At last, aiming to estimation the activity of the catalyzer prepared, a transesterification reaction was carried out. The result showed that the effect of catalyzing was worse than NaOH, this may owing to the activated component CaO turned to Ca(OH)₂ in the air, which was showed by the XRD.