The temperature of the reaction system in the hydrogenation unit is high after air cooling

It is best not to make any technical modifications to the high-pressure section, as operating at high pressures in the presence of hydrogen is quite dangerous. Measures: 1. Lower the temperature of the hot low-pressure stream; around 210 degrees Celsius is sufficient in summer. 2. Change the air cooling system from variable-frequency operation to constant-frequency operation. 3. Increase the amount of water injected by using a high-level condenser at the top of the hot high-pressure section

Modifications should be carried out based on the actual conditions on site: 1. Add misting facilities to air cooling for temperature reduction； 2. Replace with a larger air-cooled fan ； 3. If the hot air at the site is circulating, modify the site to eliminate this circulation of hot air.

This post was last edited by hlcl on 2016-8-13 at 15:27. Personally, I think it’s better to find out the reason for the high temperature in the air-cooled system and address that issue accordingly. Generally, heat exchangers are designed with a large margin of safety, so overheating is highly abnormal. Is it because the processing load is too high? Is it still fouling in the reaction effluent heat exchanger before high temperatures? Is it still fouling of the heat exchanger after achieving high scores? Is it still just the fact that air cooling isn’t effective enough? If the high-temperature level is already above the limit, it indicates that scaling has occurred in the effluent heat exchanger, and there isn’t much that can be done about it. I think the method suggested on the second floor is feasible, but adding more water isn’t a viable option – adding water increases the load on the air cooling system, and water cannot be added casually, as that could cause corrosion of the heat exchanger ； Personally, I do not recommend using the method described for the third floor; it is not feasible in practice. Spraying mist on a few of the air coolers alone can cause uneven airflow in those coolers, leading to corrosion. If mist is sprayed on all of the air coolers, it becomes very difficult to control the temperature. If the temperature is normal at high pressures but the heat exchange efficiency of the heat exchanger decreases after reaching such pressures, it is recommended to check whether there is any change in the pressure difference, and whether salt deposition is causing the reduced heat exchange efficiency. In such cases, intermittent water injection can be carried out before the heat exchanger.

The views mentioned above make sense, but I think it’s necessary to identify the real cause before coming up with solutions. I would add that it’s important to check whether there is dust or other debris on the outside of the air-cooling fins, as this can prevent proper heat transfer across their outer surface. Some time ago, we encountered problems with air cooling; by washing away the dust from the surface of the fins, we saw a significant improvement in performance.

Changing to wet air cooling or increasing the heat recovery rate should solve the problem, right?