Depression of the Cloud Point of Biodiesel by Reaction over Solid Acids (original) (raw)
Related papers
Preparation and Study of Bimetallic Compounds Efficiency in the Synthesis of Biodiesel Fuel
Catalysis Letters, 2009
In this work, biodiesel was obtained by the transesterification of babassu oil into methanol, employing as catalysts heterogeneous CuO/Al 2 O 3 , CoO/Al 2 O 3, and MnO/Al 2 O 3 . The catalysts were prepared by the method of co-precipitation, which is a mixture prepared using a solution of nitrate of Al 3? and nitrate of Cu 2? , Co 2? and Mn 2? . The catalysts were calcined into two temperatures: 400°C and 650°C. The best catalytic activity was obtained with the catalysts calcined at 400°C because at 650°C, there was a reduction in the amount of nitrates and carbonates in the structures of catalysts. The conditions for the transesterification reaction's oil babassu using the heterogeneous catalysts were evaluated and the best parameters were: 6:1 (molar ratio oil and methanol time of 24 h. The optimum condition was applied to all biodiesel obtained using the catalysts CuO 0.25)/Al 2 O 3 (CuO400), CoO(0.4)/Al 2 O 3 (CoO400), and MnO(0.4)/Al 2 O 3 (MnO400) with yields of 66.70, 98.23, and 68.10, and for biodiesels transesterified twice obtained with the catalysts CuO(0.25)/Al 2 O 3 (CuO650), CoO(0.4)/Al 2 O 3 (CoO650), and MnO(0.5)/Al 2 O 3 (MnO650) with yields of 83.67, 97.86, and 94.13%,. The use of heterogeneous catalysts was very satisfactory with respect to conversion of methyl esters (biodiesel).
Calcium zincate as precursor of active catalysts for biodiesel production under mild conditions
Applied Catalysis B: Environmental, 2009
This work investigates the use of calcined calcium zincate as solid base catalyst for the methanolysis of sunflower oil to FAME (biodiesel). The precursor and catalyst were characterized by XRD, XPS, SEM, EGA-MS, FTIR and N 2 adsorption. The thermal treatment at temperatures as low as 400 8C leads to a base catalyst which is very active and stable in biodiesel production from different vegetable oils (sunflower and soybean). The presence of carbonate on the calcium zincate, used as precursor, is negligible after remaining in contact with air for two weeks. The catalyst obtained at 400 8C shows FAME yields higher than 90% after 45 min of reaction, and the kinetic of the heterogeneous process (60 8C, methanol:sunflower oil molar ratio of 12, 3 wt.% of catalyst) is very close to that observed under homogeneous conditions (KOH dissolved in methanol). Under these experimental conditions, the catalyst is stable against lixiviation since it can be reutilized for three catalytic runs of 1 h, reaching yields higher than 85%. Moreover, by increasing the acidity of the oil until 1.18 (typical value of fried oils), the catalytic performance is maintained. The presence of water has a negative influence on the catalytic activity, since the addition of a 0.2 wt.% of water into the reaction medium decreases the FAME yield until 80% after 3 h of reaction, although this yield is still higher than 60% after adding a 1 wt.% of water. This catalyst is also very active in the transesterification of soybean oil. ß
Activity of solid catalysts for biodiesel production: A review
Fuel Processing Technology, 2009
Heterogeneous catalysts are promising for the transesterification reaction of vegetable oils to produce biodiesel. Unlike homogeneous, heterogeneous catalysts are environmentally benign and could be operated in continuous processes. Moreover they can be reused and regenerated. However a high molar ratio of alcohol to oil, large amount of catalyst and high temperature and pressure are required when utilizing heterogeneous catalyst to produce biodiesel. In this paper, the catalytic activity of several solid base and acid catalysts, particularly metal oxides and supported metal oxides, was reviewed. Solid acid catalysts were able to do transesterification and esterification reactions simultaneously and convert oils with high amount of FFA (Free Fatty Acids). However, the reaction rate in the presence of solid base catalysts was faster. The catalyst efficiency depended on several factors such as specific surface area, pore size, pore volume and active site concentration.
Catalytic upgrading of biomass-derived oils to transportation fuels and chemicals
The Canadian Journal of Chemical Engineering, 1991
This paper provides a review of the catalytic upgrading of biomass-derived oils such as wood pyrolytic oils, plantivegetable oils and tall oil to transportation fuels and useful chemicals. Both zeolite and hydrotreating type catalysts have been found suitable for upgrading which was usually done in fixed bed reactors. The hydrotreatment of pyrolytic oils at 250-450°C and 15-20 MPa H, pressures has been reported to yield up to 55 wt. % of liquid product containing 40-50 wt. % of gasoline range hydrocarbons. In the case of HZSM-5, the upgrading has been carried out at atmospheric pressure and 350-500°C and over 85 wt. % conversions of plant oils and tall oil have been achieved under optimum conditions. Liquid product yields from these oils were up to 70 wt. % of feed which contained 40-50 wt. % aromatic hydrocarbons. With the high pressure pyrolytic oil, pitch conversions of over 75 wt. % have been observed with HZSM-5 using co-feeds such as tetralin. However, there is only scant information available on the kinetic and mechanistic aspects of upgrading of these oils.
Energies, 2013
Biodiesel is a promising alternative to petroleum diesel with the potential to reduce overall net CO 2 emissions. However, the high cloud point of biodiesel must be reduced when used in cold climates. We report on the use of isomerization and hydroisomerization reactions to reduce the cloud point of eight different fats and oils. Isomerization was carried out at 260 °C and 1.5 MPa H 2 pressure utilizing beta zeolite catalyst, while hydroisomerization was carried out at 300 °C and 4.0 MPa H 2 pressure utilizing 0.5 wt % Pt-doped beta zeolite catalyst. Reaction products were tested for cloud point and flow properties, in addition to catalyst reusability and energy requirements. Results showed that high unsaturated fatty acid biodiesels increased in cloud point, due to the hydrogenation side reaction. In contrast, low unsaturated fatty acid biodiesels yielded cloud point reductions and overall improvement in the flow properties. A maximum cloud point reduction of 12.9 C was observed with coconut oil as the starting material. Results of the study have shown that branching can reduce the cloud point of low unsaturated fatty acid content biodiesel.