Response surface modeling and optimization for production of ammonia from urea in a batch reactor

Abstract

AbstractAmmonia is applied to removal of NOx contaminates contained in a flue gas stream from energy producing boilers and increase of efficiency of an electrostatic precipitator for removal of fly ash from flue gas stream from a boiler using fossil fuel. In this study, urea hydrolysis for production of ammonia, in different application areas that requires safe use of ammonia, was investigated in a batch reactor. The single and combined effects of operating parameters such as initial feed concentrations, temperature, time and stirring speed on the production of ammonia from urea were analyzed using response surface methodology (RSM). A 24 full factorial central composite experimental design was employed. Analysis of variance (ANOVA) showed a high coefficient of determination value (R2 = 0.976) and satisfactory prediction second‐order regression model was derived. The optimum production conditions were determined as temperature, 180 °C; initial feed concentrations, 22.24 wt% of urea; time, 74.9 min and stirring speed, 1150 rpm. At optimum conversion conditions, the conversion of urea for production of ammonia was found to be 75.65%. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.