Valve corrosion

Shut down the system and replace the valve. Reason: 1. Quality issues in valve manufacturing ； 2. Inspections were not conducted carefully; valves that failed pressure tests were still used.

The amine solution is N-methyldiethanolamine. The corrosivity of amine solutions is quite severe; the cause of this corrosion is generally attributed to thermally stable salts, and the amine solutions themselves also have corrosive properties. We have also encountered cases of internal leakage in several of our lean amine liquid control valves, manual valves, and bypass valves. The valves have been in use for too long; if they are used for a shorter period, it is either due to a problem with the quality of the valves or with their material composition. Not sure what problem needs to be solved? For internal leakage in simple control valves, one can use the valve stem adjustment mechanism; as for internal leakage in manual valves, it can only be resolved by replacing them during downtime. If it cannot be reduced due to excessive internal leakage flow, there should be another valve at the tower’s inlet that can be used to limit the flow.

The lean amine solution contains too many impurities. It is mainly to prevent the erosive corrosion of the valve plate caused by salts, so stainless steel valves are used. The valve should not be used for throttling as much as possible; throttling should be accomplished through a control valve. Regenerate the amine solution.

The control valve is of poor quality; the pressure regulators in my factory, which are over ten years old, still look like new.

First, consider the quality issues of the valve

1. Valve quality issues. 2. Whether the valve pressure test is qualified.

Replace the valves; we have replaced many bellows valves in our equipment, and there are still many more that need to be replaced.