| Biodiesel is an ideal substitute of petrochemical diesel, but its high cost prevents the development of biodiesel industrialization. So far it is practical to use high acid value oils and fats raw materials to reduce the cost of bio-diesel. Therefore, it is necessary for us to find a new kind of green catalyst which has great adaptability in a wide range of raw materials, and which is friendly to chemical engineering. Additionally this new kind of resource should improve economic efficiency. In this paper, we told four kinds of solid acid catalyst based on the fruits in China and abroad: activated carbon supported catalyst p-toluenesulfonic acid, sulfuric acid-modified zeolite catalyst 13x, sulphonated coal, as well as magnetic nano-catalyst ZrO2-SiO2-Fe3O4. In addition these samples were characterized to explore its catalytic mechanism. The main fruits are summarized following:1. Studied the synthesis methods of p - toluenesulfonic acid supported on activated carbon and its application on biodiesel production from oils. Catalysts of TsOH/C-A, TsOH/C-B and TsOH/C-C are synthesized in different loading amount by different methods. In this paper, we compared the different effects of 3 methods of supporting on 5 kinds of activated carbon (coal activated carbon 1, coal activated carbon 2, coal activated carbon 3, citric acid activated carbon and coconut activated carbon), the results showed that the citric acid activated carbon and the third synthesis methodare considered as the best ones. Through orthogonal experiment, the optimal conditions are found: the amount of catalyst is 10%, reaction temperature is 70℃, the molar ratio of methanol to acidified oil is 28:1, reaction time is 2h, the yield of the product reach 88.8%.2. The preparation of acid-modified 13x molecular sieve catalyst is studied. This paper shows that the BET surface areas of the catalyst decrease as the cal. temperature increases, the corresponding catalytic activity of catalyst decreased. Under the following optimal conditions: the amount of catalyst was 10%, the reaction temperature was 65℃, the molar ratio of methanol to oil was 28:1, reaction time was 2h, the yield of the product could reach up to 97.03%.3. Studied the structural transition properties of sulphonated coal in the preparation process and its application on oils with high acid value for biodiesel preparation. The catalyst was characterized by IR, SEM and XRD. IR spectra showed that there were lots of acid functional groups in the internal structure of solid acid. It is observed that the smooth coal structure has become porotic by SEM. The crystal framework of sulphonated coal was almost identical to that of coal, which was confirmed by XRD. Through orthogonal experiment, the optimal reaction conditions were obtained: catalyst dosage (based on lipin) is 20%, reaction temperature is 70℃, the molar ratio of methanol to acidified oil is 56: 1, reaction time is 2h, and the yield reached up to 93.40%.4. Studied the structural transition properties of the magnetic nano-catalyst in the preparation process and its application on the high acid value oils and fats in the preparation of bio-diesel. The physicochemical properties were characterized with N2 adsorption at 77K, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), powder X-ray diffraction (XRD), IR. Powder XRD illustrated the existence of tetragonal crystal of ZrO2 and not found the peaks of Fe3O4 indicating matrix Fe3O4 is in a highly decentralized state. IR spectra showed that there exists acid functional group in the catalyst. The BET results showed that the catalyst has mesoporous structure and large pore size distribution. By the introduction of a new recycling method, the catalyst can be reused 4 times.
|
PDF Full Text Request