Heat exchanger leakage
Thread Content
In the case of a heat exchanger leak, is it better to replace the tube bundle or the heat exchanger itself?
If only a few tubes are leaking, it’s sufficient to seal both ends; if too many tubes are leaking, then the tube bundle needs to be replaced
Please take a look at the post below, OP! Methods for dealing with a leaking heat exchanger: http://bbs.hcbbs.com/viewthread. ... 8%C6%F7%D0%B9%C2%A9
I think it’s obviously better to replace the tubes. The heat exchangers we produce are used in highly corrosive environments, and the coils need to be replaced every 1 to 2 years.
If the leakage is not severe, replacing the pipe will suffice; if it’s more serious, it’s recommended to replace the heat exchanger! There are relevant discussions on the forum; it’s recommended to take a look!
The leakage is not significant – I mean it’s no more than around 5% of the heat exchange area. It can be addressed by plugging the affected tubes or by removing and replacing those tubes on-site; if the leakage is greater, then the entire tube bundle needs to be replaced. However, for a manufacturing plant, it’s easier to just produce a new unit rather than replacing the tube bundle.
What was said upstairs makes sense! If the amount of leakage is small, just gamble with it. If the leakage is significant, the pipe needs to be replaced; and if the leakage is even greater, the heat exchanger has to be replaced!
If it’s a small, minor leak, plugs can be inserted at both ends of the leaking pipe to seal it; if the leakage is severe and there’s significant corrosion, then the pipe bundle needs to be replaced； Generally, there’s no major issue with a shell that has leaks in its tubes; there’s no need for a complete replacement, which can save a lot of money! :)
If the heat exchange tubes are not leaking significantly, they can simply be plugged up; this will have little impact on the heat exchange efficiency, and there is no need to replace the tube bundle. However, if too much leakage occurs, it will be necessary to consider replacing the entire tube bundle in order to ensure effective heat exchange. If it’s the head or the shell that is leaking, it’s not just a matter of replacement; production has to be stopped, and the problem becomes serious
If the leakage is minor, the pipe can be sealed, but this sealing must not affect the flow area of the heat exchanger; if the leakage is severe, it is recommended to replace the entire unit. Replacing a single heat exchange tube is quite difficult, and this method is generally not used in actual production.
Replace it if the housing leaks severely. Since it is a tube bundle, it is not of the fixed tube sheet type; replacing the tube bundle is more economical. Ensure good corrosion protection!
I think we should consider the costs and practical circumstances! If replacing the tube bundle can ensure normal production, then there’s no need to replace the heat exchanger! If it cannot be met, replace the heat exchanger.
If leakage occurs only at the flange connection of the equipment itself, it is sufficient to repair the sealing surface through on-site machining. Before welding, the area and depth at the weld site can be expanded by at least 3 mm to ensure the quality of the weld and reduce deformation; furthermore, a penetrant testing method is used to inspect the weld after machining, and reworking the sealing surface can also eliminate any minor deformations caused by high temperatures during welding ；
There are two types of leaks in heat exchangers: 1. Seal surface issues, which generally require removing and replacing the gasket. If there is a problem with the flange surface, it needs to be repaired. 2. Regarding the tube bundle issue, if there are few tubes, they can be sealed off using plugs made of the same material; however, if more than 1/3 of the tubes are leaking, the entire tube bundle must be replaced, as there is no longer any economic sense in continuing to use it
For leaks in heat exchangers, it is necessary to determine where the leak is occurring; if it is due to deformation of the fixed tube sheet or the flange surface, the sealing surface needs to be remanufactured； If it’s a pipe leak, plug it if the amount is small; if it’s severe, replace the pipe.
Check where the leakage is coming from: 1. Sealing surface. If the problem is a damaged gasket, replace it; if you want to extend its service life, you can make the gasket thicker. Due to the issue with the flange sealing surface, repair work is required. 2: Reason related to the heat exchange tubes: I think what was said upstairs is already very clear; if there aren’t many damaged tubes, just block them off ； If there are many, then replace the tube bundle. I assume you are from the manufacturer; everything should be considered from an economic perspective!
Block it if the process conditions are met; otherwise, replace the equipment
The main thing to consider is the number of leaking heat exchange tubes, as well as any changes in the heat exchange area that might affect normal operation. In our previous experience at petrochemical companies, if a large number of tubes were leaking and this failed to meet the process requirements, then it was necessary to replace the equipment； Or else, process the plugs to isolate the leaking heat exchange tubes
The reasons for leaks in heat exchangers are not singular, and simply replacing them is not sufficient. There are generally two reasons for leakage: one is the failure of the joint between the heat exchange tube and the tube sheet, which causes leakage ； Second, leakage occurs in the tubes at the contact points with the partition.
If the usage time is short and few heat exchange tubes are leaking, these can be plugged; this way, the heat exchange area is not reduced significantly, allowing the process to continue as usual. If there are many leaks, then the heat exchanger needs to be replaced