Continuous Packed-Bed Biodiesel Polishing Using Particulate Materials

This work reports experimental data on dry-washing of biodiesel produced by enzyme-catalyzed reaction using ion exchange resins, a commercial immobilized enzyme, and a magnesium silicate adsorbent. Experiments were carried out in continuous-mode packed-bed column, varying operating temperature and pressure, and residence time toward reachihg the current specifications of the biodiesel samples tested: Besides, the amounts of free fatty acids (FFA), raw material, and products were characterized with regard to the content of monoacylglycerol (IVIAG), diacylglycerol (DAG), and triacylglycerol (TAG). It is shown that resins and the immobilized enzyme presented, to a certain extent, satisfactory results; in terms of FFA reduction, while the use of the adsorbent allowed reaching "on spec" biodiesel. It was observed that the water content dramatically affected the quality of the final product, which severely hindered one from reaching lower FFA contents. Integration of resins together with silicate adsorbent seems to be an interesting strategy for biodiesel polishing. Pilot plant tests were also conducted using the resins with replicable results from laboratoryscale assays. Results obtained in this work are relevant for the design and operation of industrial-scale plants.