To investigate the effect of reactor performance/confi guration of biodiesel production on process parameters (mass & energy consumption, required facilities etc.), two diverse production processes (from vegetable oil) were implemented/designed using Aspen HYSYS V7.2. Two series reactors were taken into account where overall conversion was set to be 97.7% and 70% in fi rst and second processes respectively. Comparative analysis showed that an increase in conversion yield caused to consumption reduction of oil, methanol, cold energy and hot energy up to 9.1%, 22%, 67.16% and 60.28% respectively; further, a number of facilities (e.g. boiler, heat exchanger, distillation tower) were reduced. To reduce mass & energy consumption, mass/heat integration method was employed. Applying integration method showed that in the fi rst design, methanol, cold and hot energy were decreased by 49.81%, 17.46% and 36.17% respectively; while in the second design, oil, methanol, cold and hot energy were decreased by 9%, 60.57% 19.62% and 36.58% respectively.