Prepare Biomass Based Solid Sulfonic Acid For Manufacturing Biodiesel From High Fatty Acid Content Oil Feedstock

Catalyst preparation confine to present challenge in the catalyst industry. Biodiesel currently industry preparation mainly uses liquid acid-base catalyst, but the homogeneous catalysis causes major enviromental problems. Solid catalyst has the potential to solve this problem, and has found more and more applications in this filed. The merit of solid acid catalyst in biodiesel production is as follows:not easily inactivated, no high requirement on oil, can catalyses the oil with high acid value and water content. The purpose of this project is to develop the green solid catalyst with the ability of high efficiency biodiesel pruduction. Renewable bamboo residues have plenty of lignocelluloses, and are good raw material for solid catalyst---sulfonated carbon preparation. Sufforated carbon has strong acid catalystic activity, and can catalyze both esterification and transesterification reaction, which one step makes biodiesel production possible. Moreover, the solid acid catalyst could be seperated easily and resued.This research adopted the method of sulfuric acid dehydration carbonization and sulfonation to prepare biomass carbon-based solid sulfoacid catalyst using renewable lignocelluloses bamboo as raw material. Carbonization condition and sulfonation atmosphere were investigated. The results showed that the catalyst prepared by ultrasonic assisted base treatment loosened the bomboo carbon's internal aperture, and the specific surface area were improved, internal active radicals and the catalyst activity were stronger; Choice and control of bamboo carbonization condition had important effect on the follow-up sulfonation reaction. The sulfonated carbon in the condition of 80% sulfuric acid, heating temperature of 80℃, for 3h, the indefinite structure confains the sulfonic acid radical of relatively high quantity. Higher sulfonation temperature was more in favour for sulfonation reaction, the catalyst obtained by sulfonation reaction at 120℃for 5h had the optimum catalystic activity.Sulfonated carbon was characterized by SEM, XRD, BET, FTIR. The results indicated that sulfonated carbon was a kind of solid catalyst with large specific surface area and huge void volume, the aromatic ring structure of sulfonated carbon possesses function of sulfonic acid radical. These properties lead to their high catalytic activity. The thermo gravimetric curves showed that sulfonated carbon had better thermo stability, so the catalystic activity would not decrease due to its thermo break down.Homemade solid sulfonic acid catalyst was used to catalyze waste cooking oil and methanol esterification to pruduct biodiesel. Using methanol gas criculation system to make methanol, oil and catalyst into homogeneous mixture, under the reaction condition of 105℃,6:1 molar ratio of methanol to oil,4wt% of catalyst in oil for 12h, the rate of transesterification reached as high as 98.84% in the water free waste oil and could reach 98% when there was 6% liquid water in the oil. This catalyst had no spealic high requirement on acid value and liquid water content of rawmaterial, so the application range will be wideer, which should help relieve the pressure of oil feed stock shortage. The catalyst had high stability and reusability, and therfore could be a solid catalyst with widely potential applications.Swida wilsoniana oil was also refined, and then the homemade solid sulfonic acid catalyst was used to catalyze the Swida wilsoniana oil to produce biodiesel, which provided a new approach for multipurpose use of Swida wilsoniana oil and relieve pressure of raw material shortage in the biodiesel industry. Under the reaction condition of 85℃,12:1 molar ratio of methanol to oil,6wt% of catalyst in oil for 12h, the rate of transesterification reached as high as 96%. The activity of sulfonated carbon was as high as the 1.5% sulfuric acid and the main components of the fatty acid methyl esters in the two kinds of biodiesel were identical.The biodiesel was analysed for the chemical and physiochemical performance, and fond to meet that rafional biodiesel standards. The content of fatty acid methyl esters was 98%, contained plenty of unsataurated fatty acid methyl esters with high cetane number, and could meet the national standard and possessed better combustion property and low temperature flonability.