Is the material chosen for this pipe lining appropriate?
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Medium: Shell side: Pure water； Gangway: Mixed gas (hydrogen, carbon monoxide, carbon dioxide, steam) Operating temperature: Shell side: 104℃ ； Gauge pressure: 155℃ Operating pressure: Shell side: 0.3MPa ； Gauge pressure: 1.64 MPa; Material: Shell side: 20 ； Tube side: 0Cr18Ni10Ti heat exchange tubes; the tube sheet is joined using strength welding plus expansion bonding. Problem: There are constant leaks on the tube side – could this be due to an inappropriate material selection?
There may be an issue with the material chosen for this pipeline. Based on the information provided, using pure water in the shell side is a suitable choice; however, using a mixed gas (hydrogen, carbon monoxide, carbon dioxide, steam) in the tube side may lead to material incompatibility or a risk of corrosion under high temperature and pressure. Furthermore, the operating temperature of the tube train is 155°C and the operating pressure is 1.64 MPa; the 0Cr18Ni10Ti material may not be sufficient to withstand such high temperatures and pressures. The air leakage issue may be related to the material used; it is recommended to check the quality of the welding and assembly of the pipe connections to determine whether it is necessary to replace the pipe material. At the same time, it is recommended to consult a professional engineer or supplier for more accurate advice. .
Based on the pressure, temperature, and medium you mentioned, there should be no issue with selecting the appropriate material; it’s likely a problem related to the design, manufacturing, or welding process – so investigate that!
For your gas-fired boiler water preheater, it is recommended to use S316L material for the heat exchange tubes; condensate should form at the outlet of the heat exchanger! During the heat exchange process in the heat exchanger, condensate is formed. Logically speaking, the material of 321 should be fine as well
It is unknown exactly where the leakage occurs in the tube sheet – whether it is due to a leak in the welds at the tube sheet ends or due to corrosion of the heat exchange tubes. Simply from the perspective of the pipeline medium, the material chosen for design is sufficient to resist carbonic acid corrosion. It’s not clear whether an analysis of the medium’s components was conducted; perhaps other components are having an impact.
There is no issue with the material selection; the leakage must be attributed to other factors – could it be that the gas-side flow rate is too high?