Abstract
This contribution addresses the optimal design of the heat exchanger network (HEN) for an integrated soybean biorefinery plant which encompasses six process areas: (i) beans preparation; (ii) oil extraction; (iii) miscella distillation; (iv) soy oil refining; (v) sodium methoxide production; and (vi) biodiesel production via homogeneous alkaline transesterification technology. For this purpose, a two-step methodology is employed, where a Total Site Analysis is first carried to estimate the energy targets for the whole process and assess the potential utility co-generation to be distributed to the process sites through the utility system. Subsequently, the HEN design of each site is performed using the Aspen Energy Analyzer, based on a sequential procedure employing Mixed Integer Linear Programming to minimize the HEN total cost. The results obtained reveal that the heat sources in the current process configuration limit the co-generation of utilities, and therefore the process heat waste needs to be preferentially recovered through stream matches within each site. A systematic design procedure is therefore used to identify an optimized HEN configuration, achieving lower utility consumption and lower total heat exchanger area, compared with a previous reference solution. The higher number of heat exchange units of this new design is compensated with the elimination of inter-site streams matches, resulting in a process alternative simpler to implement in practice.
