How to deal with hydrolytic desorption when the urea content in ammonia water is too high
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Due to various factors such as system fluctuations, the urea content in the ammonium carbonate solution tank is **higher than the specified level (above 5%), and the amount involved is significant. Is the only way to address this issue by reducing the amount of hydrolysis, thereby gradually reducing the excess ammonia content?
Once system fluctuations occur, especially phenomena such as liquid accumulation in the evaporation system, close attention should be paid to changes in the liquid level in the ammonia tank. Should the phenomena mentioned by the poster occur, it is necessary to rapidly reduce the load on the hydrolysis unit, open the gas-phase valves of the hydrolysis tower widely to increase the steam supply to that tower. At the same time, appropriate adjustments must be made to the rectification tower to prevent overpressure in the hydrolysis tower, which could lead to overpressure issues in the rectification tower as well. Once the temperature, pressure, and other parameters in the hydrolysis tower gradually return to normal, the hydrolysis load should be increased slowly, so as to gradually consume the excess ammonia present in the ammonia tank. If the liquid level in the ammonia tank is not high, adding a small amount of external water to the tank can help reduce the concentration; this is sometimes used as a temporary solution.