543. Distillation column optimization: A formal method using stage-to stage computations and distributed streams
Invited abstract in session WB-12: Chemical and Energy Systems Optimization, stream Applications: AI, uncertainty management and sustainability.
Wednesday, 10:30-12:30Room: B100/8009
Authors (first author is the speaker)
| 1. | Tobias Seidel
|
| Optimization, Fraunhofer Institute ITWM |
Abstract
Distillation in distillation columns is a widely used process to separate liquid mixtures and plays a key role in the energy-intensive sector of chemical processes. To minimize the required energy for separation, an optimal design and optimal operation are needed. Using the MESH (mass, equilibrium, summation, heat) equations in an equilibrium stage model results in a highly nonlinear description with hundreds to thousands of optimization variables and equality constraints. Including the design in the optimization introduces discrete degrees of freedom related to the number of stages, further complicating the problem as a nonlinear mixed-integer optimization problem.
To simplify the problem, we employ distributed streams, eliminating discrete degrees and replacing them with continuous ones. To avoid sophisticated initialization procedures, we combine this smooth formulation with stage-to-stage calculations that presolve most of the nonlinear equations, reducing the problem to maintaining only the MESH equations for a single stage. For this nonlinear reduction, we can prove the existence and uniqueness of solutions, ensuring a well-defined formulation and equivalence of the optimization problems.
Our numerical experiments demonstrate the efficiency and stability of solving the proposed optimization problem in various scenarios, including single and multiple distillation columns.
Keywords
- Applications of continuous optimization
- Nonlinear mixed integer optimization
Status: accepted
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