Modeling Analysis of Stirred Tank Reactors

Continuously Stirred Tank Reactor (CSTR) was modeled and the reactor performance analyzed with a view to coming up with an essential parametric quantity useful for assessing control at the steady-state design stage. The steady-state design of CSTR and its implementation, using Matrix Laboratory (MATLAB®) program for hypothetical reaction case and the commercial software Aspen Plus® for a real chemical case was performed. The approach adopted considered two separate first-order irreversible exothermic reaction processes, implemented in MATLAB® and Aspen Plus® software respectively and a target conversion and reactor stability ratio (RSR) determined. Results from this study revealed that at varied temperatures (320-360K) under steady-state design, a suitable target conversion of 95% and RSR values less than 0.50 present minimal control problems with irreversible exothermic reactions for both hypothetical and real chemical systems. Conversely, reactor design for low conversion and maximum temperatures can present control problems with exothermic reactions due to larger reactor size and low heat transfer area. The key to improved reactor performance with minimal control problems, is designing at a reasonable low RSR value and providing excess heat transfer area so that disturbances can be properly handled.