Associated with the Center for Process Modeling & Control
phone: (610) 758-4256
fax: (610) 758-5057
Design and Control of a Coupled Reactor-Column Process
Reactive distillation is becoming more commonly employed in industry as a way to increase yields and reduce energy and capital costs. One popular version employs a stirred-tank reactor with a rectifying column mounted above it. Light-boiling products are removed from the top of the column. This drives the reversible reaction farther than it would go in just a reactor by itself. In addition, if the reaction is exothermic, the heat of reaction can be used to reboil the column. Both batch processes and continuous processes based on this technology are found in industry. However, both the steady state design and the dynamics of these coupled units are poorly understood. Simulation studies are underway and experimental confirmation of results is planned for the future.
One of the most important questions in the design of control systems for interconnected units in a plant is how to handle recycle streams. The literature in this important area is quite limited, so some good engineering research is needed. We have initiated one project to study some simple process systems with recycle. A single reactor followed by two distillation columns is under investigation. Consecutive reactions A_B_C occur in the reactor. Component B is the desired product, so the concentration of B in the reactor should be kept low so that little component C is formed. This means that the concentration of reactant A will be high in the reactor effluent, and a large recycle stream from the separation section is required. Different economic factors yield different optimum steady state process designs. Sometimes the optimum is a small reactor with a large recycle (big distillation columns), and sometimes the optimum is a larger reactor with less recycle.
Click here to view a poster that further describes these interests.