The vacuum in the final evaporation stage decreases
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The three-effect evaporator in our facility is used for evaporating ammonium chloride, and it has been working normally in the past. Now, however, we have noticed that the vacuum level in the last effect has decreased, while the vacuum level in the second effect has increased significantly. We have checked to ensure there are no blockages in the pipes or any leaks, but we’re not sure what could be causing this problem
It is possible that there is a leak in the final heating chamber, which results in a decrease in the pressure in that final stage; the pressures in the second and third stages are roughly the same. The temperature of the condensate water in the final stage is too high, and the secondary vapor in that stage is not fully condensed, which results in a decrease in the vacuum level in the final stage. The demister in the separation chamber needs to be cleaned; it’s too dirty. The specific reason is still unknown; our engineers have gone to the site, and we hope to have results in a few days. Everyone who works with evaporation, please share your insights! ! ! ! ! ! !
I’m not very familiar with the process of evaporating ammonium chloride. The evaporation vacuum level cannot be increased; from a process perspective, either the load is too high or there isn’t enough heat ； Either the evaporated gas is not removed in time. If the load is too high, the cause can be sought upstream – perhaps the load from earlier stages has been shifted to later stages ； Or there isn’t enough heat, and the control valve is stuck ； Or the tube bundle is leaking, etc. The evaporated gas was not removed in time; the cause can be investigated later – is the injector clogged? Is it time to clean the condenser? Wait, in terms of the equipment, then check whether there are any leaks in the separator or pipelines. Any area where a vacuum exists should be checked.
Could the original poster share a process diagram (for triple-effect ammonium chloride production)? This would facilitate communication. I have experience with evaporation processes, and I hope it can be of help to you