Ammonia is used as flue gas conditioning agent from urea hydrolysis as there is no ammonia shipping, handling and storage is required. In this investigation equilibrium and kinetic studies on hydrolysis of urea to produce ammonia has been carried out in a semi-batch and batch reactor. This study revealed that conversion increases exponentially with increase in temperature but with increase in initial feed concentration of urea, the conversion decreases marginally. From the catalytic hydrolysis study in a semi-batch reactor for different catalytic (TiO2, fly ash, (Ni+Fe) and Al2O3), it has been observed that the Al2O3 catalyst shows higher conversion compared to others, also fly ash behaves as a good catalyst next to Al2O3. Fly ash is a waste material originating in great amounts in combustion processes. Initial results indicated that fly ash has good catalytic capacity so it is decided to carry out equilibrium and kinetic studies using fly ash as a catalyst in a batch reactor. The effects of operating parameters such as initial feed concentrations, temperature, times and stirring speed were optimized using response surface methodology.