KINETICS OF LIQUID-PHASE SELECTIVE HYDROGENATION OF METHYLACETYLENE AND PROPADIENE IN C-3 STREAMS

A study was made of kinetic parameters of methylacetylene (MA) and pro padiene (PD) selective hydrogenation in liquid phase. C-3 cut, produce d by naphtha steam cracking, contains 93.5 wt% propylene, 3.5 wt% prop ane, 2.5 wt% MAPD and lighter hydrocarbons. MA and PD are unwanted for the propylene conversion processes in the downstream plants and are r emoved by converting them to propylene itself. For this purpose, a pal ladium based commercial catalyst was used in a lab scale trickle-bed r eactor, in the temperature range of 20-50 degrees C and in the WHSV ra nge of 70-110 h(-1), at 2.53 MPa. It was found that MAPD conversion to propylene decreases as temperature and WHSV increase. In the reaction mixture, propylene itself also reacts to give propane. However, propy lene conversion remains nearly constant in different WHSV and temperat ure values. Rate equations for MA, PD and propylene conversions were o btained by using experimental results. Kinetic parameters were calcula ted by taking into consideration external and internal mass transfer r esistances.