Thermodynamic Network Flow Approach for Chemical Process Synthesis

The FluxMax approach for simultaneous process synthesis and heat integration: Production of hydrogen cyanide

“…The methodology is structured into three steps and is illustrated in to a final state point but identifies the optimal trajectory in the thermodynamic state space via the solution of a dynamic optimization problem as was shown for catalytic and multiphase reactor design 46,47,48 . The advantage of the FMA is that any type of transition can be easily considered as shown previously for reactor design and in this contribution with the application of the FMA for simultaneous process synthesis and heat integration 39 .…”

“…the mass or heat pinch point of a process through iteratively increasing the grid points within their process operators, the applicability of the FluxMax approach is more general: its elegant formulation and discretization of the entire state space instead of the process operators leading to a network flow problem enables a direct application of the approach without reformulation or dimensional reduction of the process synthesis problem. An additional advantage of this formulation is the applicability across scales as was shown previously at the process unit and plant level 38,39 .…”

“…The flux optimization problem is formulated in such a way that integer decision variables are avoided. The approach constitutes the generalization of the linear programming (LP) formulation for the cost and energy flux distribution optimization of a chemical production network whose feasibility has already been exemplified for process unit design 37,38,39 .…”

“…All process unit models as well as the formulation of the corresponding elementary process nodes is described in the appendix. refining of the thermodynamic grid as was done for process unit design in a previous contribution 39 . Instead, the state space discretization is fine for key process units and coarse for the periphery enabling the fast identification of the most promising process candidates.…”

The FluxMax approach: Simultaneous flux optimization and heat integration by discretization of thermodynamic state space illustrated on methanol synthesis process

“…The discretization of the thermodynamic state space effectively decouples process-based nonlinearities from the network flow problem, resulting in a linear feasible region. In this way, the conceptual methodology of the linear programming approach (Schack et al, 2016 and the decoupling strategy applied in (Liesche et al, 2018) can be used as base of the proposed approach. By adding additional inequality constraints, heat integration is considered as integrated part of the flux optimization.…”