Comparison of physically mixed and separated MgO and WO3/SiO2 catalyst for propylene production via 1-butene metathesis

We examined the catalyst bed design of MgO and WO₃/SiO₂ for production of propylene via metathesis of 1-butene. WO₃/SiO₂ was used as a bi-functional catalyst for isomerization and metathesis reactions. Addition of MgO was proposed to help improve the isomerization activity and hence the propylene yield. Experimental studies were carried out to determine activity and reaction kinetics of 1-butene isomerization over MgO isomerization catalyst and 1-butene metathesis over WO₃/SiO₂ bi-functional catalyst for designing a suitable catalyst bed. Two types of catalyst bed arrangement—physically mixed bed and separated bed—were considered and compared by computer simulation. The simulations reveal that adding MgO in the separated bed by packing MgO before WO₃/SiO₂ offers superior propylene yield to the physically mixed bed. The appropriate %MgO loading in catalyst bed which offers a maximum propylene yield was found to vary (3 and 23%), depending on operating condition.