The acidic water vapor stripping heat exchanger has poor performance
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After being in use for over 2 months, the heat exchanger for acidic water/purified water in my distillation column begins to exhibit poor heat exchange performance. The temperature at the inlet of the tube side (acidic water) drops from around 110° at the beginning to over 80° now, while the temperature on the shell side (purified water) rises from around 50° at the start to about 80° currently. The last time it was opened for cleaning, it was also found that the tube shell wasn’t very dirty. The pH value of the purified water remains between 9 and 11, while the ammonia nitrogen level stays below 50; it may temporarily exceed 60. The sulfide level is always below 10. The stripping tower uses both alkali slag and alkaline solution to regulate the levels of ammonia nitrogen and sulfides. The concentration of the alkaline solution is generally around 15, while that of the alkali slag is around 11. The processing capacity is typically 80 tons per hour. I would appreciate it if fellow sailors could help analyze the reasons for the rapid decline in heat exchange efficiency.
We all face blockages in the shell side; for this reason, we have several sets of heat exchangers for exchanging heat between purified water and raw materials. It’s no problem if at least one set is not in use, and it’s even fine if two sets are not in use either – we can switch to use another set whenever necessary for cleaning. But I’ve never seen such a big change in just two months.