THE ROOTS OF CHEMICAL REACTION ENGINEERING

It might be impossible to pinpoint a precise time of birth for chemical reaction engineering, but some milestones are worth noting. The central issue in chemical reaction engineering is to determine the residence time, which is needed to obtain the desired product with specified quality requirements. This idea has existed in the human mind since time immemorial, starting from food preparation over an open flame. An excellent example of an early developed chemical reactor is the empirical construction of a blast furnace for the treatment of iron ores a semibatch reactor with an optimized shape. The equipment was developed empirically throughout centuries, whereas today advanced mathematical modeling is applied to predict the behavior of iron production units. 

A characteristic feature of industrially applied chemical processes is the prominent role of reaction kinetics. The vast majority of industrially applied chemical reactors are slow, and chemical equilibria do not prevail in the system. This is why the classical branch of physical chemistry, namely chemical kinetics, plays a central role in chemical reaction engineering. Kinetics provides us with a method to predict the residence times needed for product formation. 

Two pioneers of chemical kinetics who made great contributions should not be forgotten, namely, the Dutch and Swedish Nobel Prize winners Jacobus Henricus van t Hoff and Svante Arrhenius. In his monograph Etudes dynatnique chimique, van t Hoff described the temperature dependences of rate and equilibrium constants with exponential functions (exp(— /(PT))), which have a sound physical background and are sufficiently accurate for most industrial applications. Svante Arrhenius demonstrated the usefulness of this expression in many practical cases. The Arrhenius equation is still the most common expression used for the temperature dependence of rate constants. 

---