Urea hydrolysis system

Application

Urea hydrolysis system by U2A process is widely used to convert urea to ammonia for flue gas deNOx by SCR/SNCR.

U2A process flow

Urea particles are sent to urea solution preparation tank from storage silo. Inside preparation tank, urea mixes with desalted water. The mixture is heated and stirred to make sure urea is all dissolved, and urea solution could reach desired temperature and concentration. Then the solution is pumped to storage tank. Inside storage tank, urea solution is filtered and then pumped to urea hydrolysis reactor.

Urea hydrolysis reactor is steam heated U tube heat exchanger made of 316, 316L or 2205. Steam goes through tube pass, while urea solution goes through shell pass. Urea will decompose into ammonia and carbon dioxide finally. Gases released from hydrolysis reactor is mixed with hot dilution air, which should be higher than 175℃ to avoid formation of carbamate. Hydrolysis reactor should also play as buffer tank to provide adaptability in response to boiler load changes.

(x)H2O + NH2CONH2 → NH4COONH2 + (x-1)H2O
NH4COONH2 + (x-1)H2O → 2NH3 + CO2 + (x-1)H2O

Features

1. U tube structure to eliminate thermal stress, high thermal efficiency.
2. Pressure gauge & level gauge & thermometer for gaseous product, pressure gauge & thermometer for condensate water, pressure gauge for steam is equipped.
3. Safety relief valve, drain valve, reflux valve is equipped.
4. Steam & condensate blowdown function provided.

Technical

Urea solution concentration: 40~60wt%
Temperature inside urea hydrolysis reactor: 140~160℃
Pressure inside urea hydrolysis reactor: 0.4~0.6MPa
Heating steam pressure: 0.8~1.2MPa saturated steam
Gaseous product pressure: ~0.35MPa

Urea is non-toxic, stable, non-flammable. Urea-based denitration process is safer than the process by anhydrous or aqueous ammonia.

As experienced manufacturer in China, we provide complete solution for SCR/SNCR.