(305a) Production of High Quality Biodiesel Fuel From Waste Cooking Oil Using Anion-Exchange Resin Catalyst

The anion-exchange resin has a high catalytic activity for the transesterification of triglycerides to produce fatty acid esters, used as biodiesel fuel¹⁾.   The principal advantage of the production process of biodiesel fuel using the anion-exchange resin catalyst can be summarized as follows: 1) The alkali soap, contaminant for the fuel, is never formed by saponification²⁾.   2) The impurities contained in the raw oils, such as free fatty acid (FFA) and dark pigment, are removed by adsorption on the resin^2,3).   3) The complete conversion can be achieved even at the stoichiometric molar ratio of 3:1²⁾.

By combining the catalytic activity and adsorption ability of the anion-exchange resin, the high quality biodiesel fuel would be produced without the pretreatment of the raw oils and the purification of the products.

2. Experimental methods

By supplying the mixed-solution of waste cooking oil and methanol to the expanded-bed reactor packed with the anion-exchange resin, the continuous production experiment of the fatty acid methyl esters (FAME) was performed.   The effluent from the reactor was analyzed to check the quality of the biodiesel fuel.

3. Results and discussion

Figure 1 shows the time courses of the triglyceride residual ratio and the FAME concentration in the effluent from the column.   The starting time to supply the reaction solution to the column was set to zero.   The open and filled symbols were the results using the original resin and the reused one after regeneration, respectively.   Both symbols almost overlapped each other and the resin could be repeatedly used without any loss in the catalytic activity.   The FAME concentration increased after 3 h and became constant after 10 h, when the steady state was attained.   The triglyceride residual ratio was almost zero up to 25 h. so that the transesterification was found to completely proceed.

The result to check the quality of the biodiesel fuel is listed in Table 1 compared with standards of Europe (EN14214) and USA (ASTM D6751).   The component properties are picked up.   The contents of impurities (FFA and water), unreacted reactants (methanol and glycerides), and the byproduct (glycerin) in the effluent from the reactor fully satisfied with both standards.   Only the FAME content was a little lower than that in EN14214, but it was not limited in ASTM D6751.   From these results, water and glycerin as well as FFA and pigment were found to be removed by the adsorption on the resin.   The distillation process to remove the residual methanol from the product can be omitted in this system.

4. Reference

1) N.Shibasaki-Kitakawa et al., Bioresour. Technol., 98, 416 (2007)

2) T.Tsuji et al., Energy Fuels, 23, 6163 (2009)

3) N.Shibasaki-Kitakawa et al., Energy Fuels, (2010) in printing

Fig. 1 Time courses of FAME concentration (a) and triglyceride residual ratio (b) in effluent from reactor

Table 1 Component properties of effluent from reactor compared with standards of biodiesel fuel