In situ synthesis of ammonia by catalytic hydrolysis of urea in the presence of aluminium oxide for safe use of ammonia in power plants for flue gas conditioning

摘要

Ammonia is applied to increase the efficiency of an electrostatic precipitator for fly ash removal from a flue gas stream from a boiler using fossil fuel. In the present work, the hydrolysis of urea to generate ammonia for flue gas conditioning, with the help of aluminium oxide catalyst, has been studied. Results: The effect of temperature, catalyst and initial concentration on the conversion was studied. Conversion was found to increase exponentially with temperature. Addition of catalyst resulted in an increase in conversion. Experiments were conducted with different doses of catalyst, and the optimum dosage of catalyst for a particular feed concentration was determined. A decrease in conversion was observed when the initial concentration of ammonia was increased. Conclusion: A study of reaction kinetics showed the effect of reaction time on conversion of urea to ammonia. The catalytic hydrolysis of urea, using aluminium oxide behaved as a first-order reaction; the rate constant at different temperatures was found, and the activation energy determined.