Equilibrium and Kinetic Studies on the Hydrolysis of Urea for Ammonia Generation in a Semibatch Reactor

Abstract

The present study is concerned with the methods and means to safely produce relatively small amounts (i.e., up to 50 kg/h) of ammonia. The equilibrium and kinetic study of urea hydrolysis was conducted in a semibatch reactor at atmospheric pressure to investigate the effects of reaction temperature, initial feed concentration, and time on ammonia production. This study reveals that conversion increases exponentially with increasing temperature but decreases slightly with increasing initial feed concentration of urea. Furthermore, the effect of time on conversion was also studied; it was found that conversion increases with increasing time. Using collision theory, the temperature dependency of the forward rate constant was determined, from which the activation energy of the reaction and the frequency factor were calculated. The activation energy and frequency factor of the urea hydrolysis reaction at atmospheric pressure were found to be 60.93 kJ/mol and 4.259 × 105 min−1, respectively.