화학공학소재연구정보센터
Chemical Engineering Communications, Vol.169, 111-136, 1998
Importance of reaction structure in the periodic operation of six industrial chemical reactions
Periodic operation occurs when a reaction is run with periodic inputs in reactant flowrate, concentration, temperature or in other conditions. Periodic operation of chemical reactions Leading to enhanced rates and yields as compared to steady-state operation has been reported for three decades. Emphasis has been on the study of reactions which are often catalytic and have varying reactor designs that affect the responses to periodic operation. The reported reactions often have mass transfer limitations, catalyst adsorption - desorption behavior, surface reactions, or temperature effects and the magnitude of the the periodic response is often affected by these factors. The objective of this paper is to compare the reaction networks of six industrially important reactions to investigate the importance of reaction structure on the potential for conversion and selectivity improvement using periodic operation. Dynamic simulation techniques are used to solve the coupled differential equations representing the reaction rates. It is assumed for comparison purposes that there are no mass transfer limitations, that adsorption -desorption or surface reactions are not rate limiting, and the temperature is constant at the reaction conditions. One reactor design, the continuously stirred tank reactor, is used in order to compare reactions without reactor design-related effects. Differences in the periodic response are related to reaction structure factors such as the number of chemical components, the number of first order reactions, and the number of series reactions present. Reaction structure does not appear to be as significant as non-structural factors such as mass transfer, catalyst behavior, or reactor designs in creating periodic operation improvements.