(391n) Experimental and Simulation Study of a Universal Procedure for Crude Glycerol Purification From Different Feedstocks in Biodiesel Production

With increasing supply and decreasing price, from the economic point of view, it is important to utilize crude glycerol, the main by-product of biodiesel production, to manufacture high value-added chemicals. Since crude glycerol typically contains less than 65 wt % glycerol and a variety of other components, its purification is the first step for its utilization. Owing to the wide variety of triglycerides, alcohols, catalysts and separation processes used in biodiesel production, the composition of crude glycerol from different biodiesel production methods varies widely. For this reason, glycerol purification processes are also generally different for the various crude glycerol feedstocks. In the present work, we have developed a universal procedure for crude glycerol purification, and utilized it for crude glycerol samples from two biodiesel production companies, experimentally upgrading both to >94 wt % purity. On Aspen Plus software platform, the purification procedure was simulated using a process model based on modeling of phase equilibrium behavior and modeling of NaCl solubility in ethanol-glycerol mixtures, to obtain good match with the experiments. Using the same model, two other glycerol purification processes described in the literature were also simulated and high purities were also obtained according to the simulation results. We thus demonstrate that the developed universal procedure is suitable for purification of crude glycerol obtained from different biodiesel production technologies.