Is the circulating water pre-coated?
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We parked the unit for about 17 days, and carried out process modifications on the circulating water pipeline; most of the heat exchange equipment had its covers removed for cleaning. It is now about to be put into operation, and I think pre-coating is necessary, but many people say it isn’t required. What should I do
Call your boss directly, reason with them and appeal to their emotions, explaining the pros and cons: Q :Q :Q. If that still doesn’t work, I suggest you change jobs; such a company won’t have any prospects for growth, and there’s nothing worth staying for. Just because you’re the official moderator of the nitrogen fertilizer section on Haichuan Forum, which fertilizer company wouldn’t hire you? ;P ;P ;P . (Actually, I mean you’re good at technology; hehe, just my personal opinion for reference only.)
Pre-coating a heat exchanger can prevent corrosion and extend its service life. However, some pre-coating materials are similar to paint, which can affect the heat exchange efficiency. During pre-coating, it is not possible to apply the coating to the central part of the heat exchange tubes, and the pre-coating liquid that settles in the center results in an uneven coating thickness, thereby also impacting the heat exchange efficiency. However, for those using electroplating to apply a pre-coating, the entire heat exchanger core is placed in a pre-coating tank during the process, and a metal protective layer is deposited on the outer surface of the heat exchange tubes; this method yields excellent results, though the cost is relatively high. The poster’s question concerns the application of a pre-film coating on the urea heat exchanger; in my opinion, this is not necessary. It is sufficient to clean it regularly with high-pressure water during the annual major and minor repairs, and it is also advisable to add chemicals to the circulating water to prevent algae growth. This post was last edited by lxq700918 on 2009-3-17 08:26.]
Personally, I think it is very necessary to perform pre-coating on the urea heat exchanger. In fact, whether it is water from the urea cycle or that from the ammonia synthesis cycle, system corrosion and scaling are often caused by starting up and shutting down the system, especially shutdowns. If the shutdown duration is long, such as in the case described by the poster, the membrane on the urea heat exchanger suffers significant damage – damage that is several times greater than that that occurs during normal operation. It is therefore necessary to carry out pre-coating of the membrane.