[Q&A Question 200] 2018.07.25
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This post was last edited by 955559 on 2018-7-25 09:05. [Q&A Question 200] 2018.07.25: Briefly explain why some heat exchangers exhibit good heat transfer performance at first but then see that performance deteriorate over time During use, deposits (sludge, coking, scaling, etc.) gradually accumulate on the inner and outer surfaces of the tubes. These deposits are generally sulfur-rich and porous substances with a low thermal conductivity, which increases the thermal resistance and thus reduces the overall heat transfer coefficient; as a result, the heat exchange efficiency deteriorates over time. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Due to an emergency with an online anonymous user, it’s not possible to access the internet this morning. I will be issuing today’s daily question, while he will provide the grading later in the evening. 3 correct for wealth, 1 incorrect for wealth ； Mass posting of posts – rated based on the lowest score ； Replies that are unrelated to the answer are considered spam and will be deleted immediately. For management purposes, if you need to view content from a few days ago, please go to https://bbs.hcbbs.com/home.php?mod=space&uid=3862647&do=thread&view=me&from=space through the summary post below
During use, deposits (sludge, coking, scaling, etc.) gradually accumulate on the inner and outer surfaces of the tubes. These deposits are generally sulfur-rich and porous substances with a low thermal conductivity, which increases the thermal resistance and thus reduces the overall heat transfer coefficient; as a result, the heat exchange efficiency deteriorates over time.
Blockage of the heat exchanger tube bundle due to coking and other reasons, blockage in the shell side due to salt accumulation, internal leakage within the heat exchanger tube bundle, internal leakage caused by damaged gaskets on the small floating head, change in the heat exchange medium
Scaling on the outer wall reduces the overall heat transfer coefficient
First, the gas collection was not discharged in a timely manner； 2. Scaling reduces the heat transfer coefficient.
1. Cold or hot media tend to form scale, resulting in poor heat transfer efficiency； 2. The cold or hot medium channels are prone to blockage, affecting heat exchange.
It must be due to the effects on the inner and outer walls of the tube, or impurities in the medium blocking the heat exchange process.
During use, deposits (sludge, coking, scaling, etc.) gradually accumulate on the inner and outer surfaces of the tubes. These deposits are generally sulfur-rich and porous substances with a low thermal conductivity, which increases the thermal resistance and thus reduces the overall heat transfer coefficient; as a result, the heat exchange efficiency deteriorates over time.
The tube bundle is blocked, or there is excessive scaling on the outer wall of the tubes in the shell side
During use, deposits (sludge, coking, scaling, etc.) gradually accumulate on the inner and outer surfaces of the tubes. These deposits are usually sulfur-rich and porous substances with a low thermal conductivity, which increases thermal resistance and thus reduces the overall heat transfer coefficient; as a result, the heat exchange efficiency deteriorates over time.