The relationship between hydrolysis temperature and hydrolysis efficiency

1. Hydrolysis process: Slurry process. 2. Hydrolysis temperature: 235 degrees Celsius. 3. Hydrolysis load: Total feed load for hydrolysis: 45 T/h. 4. Amount of steam used for hydrolysis: Normally 2.5 T/h, with steam at 323 degrees and 3.7 Mpa. 5. Hydrolysis effect: The ammonia and urea contents in the hydrolysis wastewater are below 10 and 5 PPm, respectively.

1. Hydrolysis process: Snamicabon process. 2. Hydrolysis temperature: Around 200°C. 3. Hydrolysis load: The total feed load for the hydrolysis step is 40 T/h. 4. Amount of steam used for hydrolysis: Under normal conditions, it is 5 T/h of superheated steam at 370 degrees and 3.8 Mpa. 5. Hydrolysis effect: The ammonia and urea contents in the hydrolysis wastewater are below 10 and 5 PPm, respectively.

1. Hydrolysis process: Snamicabon process. 2. Hydrolysis temperature: 200–210°C. 3. Hydrolysis load: The feed rate for the entire hydrolysis process is around 32 T/h. 4. Amount of steam used for hydrolysis: Under normal conditions, it is 2 T/h of steam at 250 degrees and 2.5 Mpa. 5. Hydrolysis effect: The ammonia concentration in the hydrolysis wastewater is 10–20 PPm, while the urea content is around 20 PPm.

1. Hydrolysis process: Snamicabon process. 2. Hydrolysis temperature: 200–210°C. 3. Hydrolysis load: The feed rate for the entire desorption–hydrolysis process is around 40 T/h; however, we added another batch of waste liquid from desorption to the hydrolysis tower, which increased the load further. 4. Amount of steam used for hydrolysis: Under normal conditions, it is 1.2 T/h of steam at 250 degrees and 3.2 Mpa. 5. Hydrolysis effect: The ammonia concentration in the hydrolyzed waste liquid is 10–30 PPm, while the urea content is around 30 PPm.

1. Hydrolysis process: Snamicabang. 2. Hydrolysis temperature: In actual operation, it is generally 185°C for the gas phase and 205°C for the liquid output. 3. Hydrolysis load: Under normal conditions, the feed load for desorption–hydrolysis is around 31 T/h. 4. Amount of steam used for hydrolysis: Under normal conditions, it is 1.5 T/h of steam at 2.5 Mpa. 5. Hydrolysis efficiency: The ammonia content in the hydrolyzed liquid is 15–30 PPm, while the urea content is around 250 PPm； Analysis shows that the ammonia level in the waste liquid is less than 10 PPm, while the urea content is around 250 PPm. I suspect that our urea content analysis is inaccurate, but our water is sent to the gas generator, where corrosion occurs in the gaseous phase of the exhaust gas; the reason for this is unknown. Last edited by 1025199692 on 2009-2-22 22:37.]

The higher the hydrolysis temperature, the more complete the hydrolysis of urea. Based on the discussions of the above individuals, the performance of the hydrolysis-desorption units is not satisfactory, especially in the manufacturer where the actual moderator works. The actual hydrolysis-desorption issue is a systematic one; in China, the purification water coming out of the desorption towers currently has ammonia and urea levels below 5 ppm. In several large-scale urea production facilities, these levels are below 3 ppm, and the consumption of high and low pressure steam is not high. From what I know, in the few companies I’m aware of, the problems mostly lie in the desorption tower. In particular, with the Snamica process, the unit on the 6th floor appears to have an annual production capacity of 300,000 tons; in reality, the hydrolysis-desorption system exceeds the capacity specified in the original process package. The designed processing capacity was approximately ~22 t/h; as a result, the desorption tower operated under overload conditions, and flooding sometimes occurred. This was especially true when the ammonia content increased, leading to an increase in ammonia in the water fed into the desorption tower. Even if the residence time was sufficient and the temperature and pressure met the design specifications, the hydrolysis of urea was not complete. Consequently, the levels of ammonia and urea in the purified water exiting the desorption tower exceeded the specified limits. Domestic design firms used foreign process packages, without fully understanding some of the issues associated with them.

The urea plant on the 5th floor should have an annual production capacity of 520,000 tons. Another batch of desorbed waste liquid is added to the hydrolysis tower; at this point, more attention must be paid to the operation of the desorption tower. If there is sufficient headroom, the amount of low-pressure steam fed into the tower should be increased, in order to reduce the ammonia content coming out of the first desorption tower and thereby improve the efficiency of the hydrolyzer. I wonder where the purified water delivered by the people upstairs is being taken? Is it to the desalination station or to the cooling water circulation? The gasification unit used by the poster on floor 6 employs coal gasification at atmospheric pressure; the pressure of the steam in the jacket is not high. The purified water coming from the desorption tower is barely usable. Corrosion in the gas-phase pipelines is a normal phenomenon, but the existing problems need to be addressed. Discharging the purified water from the desorption tower into the cooling water system is a waste. The purified water has high quality; it is a shame that the wastewater from the hydrolysis-desorption system cannot be utilized at a high level, especially given the shortage of water resources and the increasing costs associated with water treatment in high-pressure boilers. It’s a personal encounter; let’s discuss it together.