The ammonia production methods used in power plants include urea pyrolysis and hydrolysis.Numerical simulation was conducted by Aspen Plus for the two processes in a 300 MW coal-fired power plant.From the aspects of urea feed mass fraction

reaction temperature and pressure

the effects of reaction condition on hydrolysis products were investigated. The results show that

compared with pyrolysis

the hydrolysis scheme has a lower reaction temperature

its energy consumption is only about 20%～30% of that of pyrolysis. What's more

low-quality steam can be used as the heat source of the hydrolysis scheme. From the point of energy saving

hydrolysis to ammonia is the best method. The simulation result shows a same tendency with the experimental data

verifying the reliability of the hydrolysis model. When the urea feed mass fraction was increased

the ammonia concentration in the product gas increased

the heat consumption decreased

while the urea in the liquid also increased

which leads to a rise in the risk of corrosion. As the temperature increased

the urea hydrolysis rate increased

but the heat consumption rose rapidly

and the economy was poor. Increasing the pressure can reduce the risk of corrosion. However

excessive operating pressure will inhibit the release of gaseous products.Considering comprehensively

the condition with urea feed mass fraction of 50%

temperature of 150 °C～160°C and pressure of 0.6～0.8 MPa is suitable for the urea hydrolysis.