In-service inspection of graphite shell-and-tube heat exchangers
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This post was last edited by Stay calm HAPPY on 2018-2-26 at 11:16. For the regular inspection of shell-and-tube heat exchangers, is macroscopic inspection generally sufficient for the graphite components? Are there any other methods to assist? Thank you!
The regular inspection of graphite heat exchangers involves checking the surface finish of the graphite, the presence of scaling, the degree of corrosion of the casing, and the condition of the joints. Ultimately, a pressure test is necessary to determine whether there are any leaks and to assess the pressure resistance of the device.
Far-field eddy current can be used for inspecting heat exchange tubes.
Is air pressure or water pressure generally used? What is the typical pressure? Is there any information on this? Thank you!
Have you ever used graphite tubes for far-field eddy current testing? How effective is it?
The hydrostatic test is generally carried out at 1.25 times the design pressure; for conventional equipment, the test pressure for the shell side is 0.5 MPa, while for Class A4 pressure vessels, it is determined based on the design pressure. --
For pressure testing, it’s always hydraulic pressure; how do you think air pressure could be used?
Airtightness testing is generally not performed, but if the medium is highly hazardous or water-sensitive, airtightness testing is required, with the test pressure being the maximum operating pressure.
Is it due to the concern that the impact of gas when airtightness is maintained could damage the graphite heat exchange tubes, or is there some other reason? The medium used in our graphite heat exchangers is hydrochloric acid.
In the industry of chemical equipment made of graphite, airtightness tests are generally not conducted; however, such tests are necessary if there are specific requirements imposed by the process.