Heat exchanger heat transfer tubes
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Our company’s conversion system’s four-stage heat exchanger originally used seamless steel tubes with a diameter of Φ51x3 as the heat exchange tubes. In order to extend their service life, we now intend to replace these tubes with seamless tubes of Φ51x3.5. I would like to ask if this change will have a significant impact on the heat exchange efficiency of the exchanger Or it doesn’t have much of an impact. I also have another question: is there any difference between using seamless tubes and 20g boiler tubes for the heat exchange tubes in the conversion system, or are there any disadvantages associated with either choice?
For the modified heat exchanger, adding 0.5 mm to the wall thickness has a minimal impact. As for the material, the standard requirement is 20g; it can withstand temperatures of 300 to 600 degrees, but ordinary seamless steel pipes will also work in practice. The margin factor for heat exchangers is generally around 30%. As long as the heat exchange area is not significantly adjusted, it can be adapted. In terms of material, 20g versions will also develop a large amount of oxide scale when switched between grades 1 and 2.
There is no need to use 20g boiler tubes for conversion; their performance is no different from that of seamless tubes. During major repairs, it is sufficient to clean the tubes, replace them, or plug the openings. As long as the heat exchange area is sufficient, there is no need to replace all of them with another specification.