(188h) Comparison of Capacity Expansion Strategies for Chemical Production Plants and Consideration of Alternative Modular Reactors with a Larger Operating Window

Global competition, shorter product lifecycles and uncertain product demand developments lead to changing operating conditions that conventionally designed plants, optimized for a single operating point, cannot handle sufficiently. In this context, new approaches like a step-wise capacity expansion of production plants as well as the use of modular equipment gain attention.

In the scope of this work, a methodology to determine suitable capacity expansion steps along a given market scenario is developed and applied for line-wise and equipment-wise capacity expansions. In the equipment-wise capacity expansions single process units are added to increase the plant`s production rate while complete production lines are added in the line-wise capacity expansions. The economically most beneficial points in time as well as the appropriate size of an equipment-wise capacity expansion step are identified based on a predefined equipment database.

Rigorous models are used for process simulation and the determination of process-technological and hydrodynamic operating boundaries. For the equipment-wise capacity expansion, an evolutionary algorithm combines the modular equipment to modular plant setups and optimizes these combinations in order to find the most economic equipment-wise expanded plant setups for a given market scenario.

By applying the methodology developed, equipment-wise and line-wise capacity expansion strategies are compared to each other as well as to a conventional design under changing market demand developments. In the course of the generation of the equipment database, alternative modular reactors with a larger operating window are designed to show their influence on the overall plants operation and profitability.

The developed methodology is applied to the dehydrogenation of isopropyl alcohol to acetone. It will be shown that the profitability of a chemical plant can be increased by using step-wise capacity expansions compared to conventional plant design. Additionally, the equipment-wise expansion strategies show advantages compared to line-wise capacity expansion strategies in most cases.

Furthermore, the application of the modular reactors with a larger operating window lead to an improvement of the overall production plantâ??s operating window and consequently its profitability under changing market conditions.

The results of this work can lead to a shift in the focus of plant design in chemical and biochemical engineering by incorporating step-wise capacity expansions and by applying modular equipment with a large operating window.