Exploratory Research On Glycerol Hydrogenation For EG Production

With the continuous development of the biodiesel industry, a large number of glycerol generated as by-products is in excess of the state and its price is falling. Glycerol is an ideal renewable material. Using glycerol to produce high value-added chemicals is becoming a hot issue in current research.The present work aimed at converting the biodiesel byproduct-glycerol into ethylene glycol by selective catalytic hydrogenation. The main content is divided into the following three parts:(1) thermodynamic calculation about hydrogenation of glycerol, estimated the reaction heat, the Gibbs free energy and the equilibrium constants of the reaction may occur in the system.(2) Investigation of the process conditions on the influence of ethylene glycol selective using the homemade Raney-Ni catalyst in the autoclave. The appropriate condition is:T=210℃, P=8MPa, t=8h. The Langmuir-Hinshelwood kinetic model was established to reasonably describe the reaction process, which proved the pathway of the reaction.(3) Hydrogenation isothermal reactor was simulated by Aspen Plus Software. Through the sensitive analysis of the various operating parameters, this work obtained a optimized operating condition:T=210℃, P=8MPa, H/Oil=0.12wt/wt, WHSV=2Kgglycerol/h/Kgcat. Further RadFrac module was used to simulate the dividing wall column to determine the operating parameter:22trays of B1column, the eighth one was the feed plate, R1=1.78,98.2%of methanol was discharged from the condenser,30trays of B2column, R2=2.50,97.3%of ethylene glycol was discharged from tower bottom. The interconnected position of the two towers is the22rd tray.