Commissioning of low-temperature methanol-washed ammonia cooler
Thread Content
A. The system should introduce ammonia slowly, and pay attention to observe that the temperature difference between the inlet and outlet of each ammonia cooler does not exceed 15°C. I see such data in the information, how do I understand it? What are the hazards?
In fact, it is the impact of too large a temperature difference on the material. I guess you also know the cooling rate of circulating methanol. Generally, units stipulate that this cooling rate is no more than 6 degrees per hour, and some units stipulate it to be even lower. But for an experienced operator, this cooling rate value is just an "official value". How to understand it? In other words, this value is just a rough value reported to the leader or given to you in the operating instructions. If we only give you this value now, how do you grasp the cooling rate? You increase the liquid ammonia a little, and within ten minutes, the temperature entering the main scrubber has dropped by 2 degrees. After calculation, the temperature must have dropped faster. When you reduce the liquid ammonia again, more than ten minutes have passed, and it has not dropped by 1 degree. Moreover, this temperature has a large hysteresis, so it is difficult to explore. But if I give you a "solution temperature difference between the inlet and outlet of the ammonia cooler", you can have a good grasp of it. First give you a temperature difference of 10 degrees. Check the cooling rate after one hour, so you can grasp the cooling rate in a short time.
Well, that's right. study * Yes, haha
Since the temperature of methanol is high at the beginning, the heat exchange rate of the ammonia cooler is large, and the temperature difference between the inlet and outlet of each ammonia cooler exceeds 15°C, which easily causes gas ammonia to be entrained with liquid ammonia.
Large temperature differences can easily cause gas ammonia to entrain liquid ammonia