(537g) Simultaneous Process Synthesis and Heat Integration Using Building Block Superstructure

Authors: 
Demirel, S. E., Artie McFerrin Department of Chemical Engineering, Texas A&M University
Li, J., Artie McFerrin Department of Chemical Engineering, Texas A&M University
Hasan, M. M. F., Artie McFerrin Department of Chemical Engineering, Texas A&M University
Efficient energy utilization is a paramount factor for the profitability and sustainability of a chemical plant as cost of the end-product and environmental impact of the process is highly dependent on the energy consumption of the process. Hence, the degree of heat integration within the process is an important decision that has to be handled together with the synthesis and design of the process. Currently, there are several methods available in the literature for the simultaneous process synthesis and heat integration [2-6]. These methods are mainly demonstrated for the classic superstructure representations which are based on pre-specified equipment types and priori postulated flowsheet connectivity.

Building-block based superstructure [7], on the other hand, can yield non-intuitive flowsheets while considering different mass integration alternatives without a priori postulation of the processing steps and the connectivity between them. This representation is based on a two-dimensional grid structure where several different phenomena, e.g. reaction, V-L equilibrium, G-L equilibrium, etc., can be represented either as a ‘single block’ or via multiple neighboring blocks sharing a common boundary. This provides a generic representation method for novel intensified equipment design and synthesis. Recently, this method has been also demonstrated for equipment-based representation along with detailed design formulations [8]. Furthermore, the method has been applied for different process integration problems including mass integration, heat integration and property integration [9-10]. In this work, we will show that the building block representation method can be also used to perform simultaneous flowsheet synthesis and heat integration. The formulation is based on a single mixed integer nonlinear programming (MINLP) model. As the flowsheet connectivity and equipment types are not specified a priori, the heat integration formulation is based on a generic formulation that can handle streams with unknown identity (i.e. hot/cold). Owing to its fundamental outlook toward process synthesis, building-block superstructure with heat integration enables to design, synthesize and discover new processes including refrigeration cycles without specification of the processing routes beforehand. With this, proposed method becomes a powerful tool for the synthesis of more sustainable and energy efficient processes for a variety of applications which will be demonstrated by several case studies.

References:

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[8] Li, J.; Demirel, S.E.; Hasan, M.M.F. Process Synthesis using Block Superstructure with Automated Flowsheet Generation and Optimization. AIChE Journal, 2018, under review.

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