How to troubleshoot internal leaks in heat exchangers?
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The Third Distillation Unit of our plant is equipped with over a dozen sets of heat exchangers. Some of these are experiencing leaks, and they are used for heat exchange with crude oil or vacuum residue. Crude oil or vacuum residue has leaked into this unit, causing the color of the wax oil to turn black. However, the unit has an upward reflux flow of around 800 T/T, which results in the entire Third Distillation Unit system being contaminated. The current approach is to remove the heat exchangers in groups and conduct inspections, but after almost five days, it has still not been possible to determine which one is leaking. Excuse me, are there any other good methods for troubleshooting?
It would be best to send a video of the actual setup so we can see what these types of heat exchangers look like; it’s more intuitive to go by visuals. Typically, such heat exchangers are equipped with bottom discharge valves and top vent valves for the media on both sides; by using the discharge from these valves, it is possible to determine the density and pressure difference of the media. It’s troublesome if it isn’t set, so it’s best to take a look at what the device looks like for reference.
Just take a regular floating-head heat exchanger – it has everything needed for emptying and the like. The problem now is that there is backflow in the process of reducing to three lines; the entire system has become contaminated, and it’s no longer possible to conduct visual inspections through sampling
Pay close attention to the process and equipment diagrams, starting with the details.
Cut off the heat exchanger; apply water pressure to one side while draining the other side. Alternatively, stop the reflux and conduct an inspection
Is it possible to provide a flow diagram of the decompression tower for me to see?
With the complete removal of the construction of the third line and its replacement with crude oil, after ensuring that the color of the auxiliary line meets the standards, any leaks in the heat exchangers can be detected one by one
In our catalytic reforming pre-hydrogenation unit, whenever the refined oil produced fails to meet the specifications regarding sulfur content, the issue is addressed by working backward. Sampling for sulfur analysis is required in basically every location. I’m not sure if it applies to atmospheric and vacuum distillation
But the problem now is that reducing the third line has resulted in 800T of backflow, and the entire system has become contaminated. So far, each group of heat exchangers has been tested separately, but it hasn’t been possible to identify which group is leaking; it’s likely that more than one group is leaking
It is recommended that, in terms of the processing approach, first determine whether it is crude oil or vacuum residue that has leaked based on material balance, in order to narrow down the area that needs to be addressed. Using the ledger on the equipment, identify which devices have potential hazards; those with a high likelihood of leakage should be isolated and monitored first.