Leaking of Sweet Naphtha vapouriser exchanger in H2 unit

[Naiduat]

Our Hydrogen plant is designed by M/s Technip. In the feed desulphurisation section, an exchanger (Process gas from HT shift reactor Vs Sweet Naphtha) is suspected to be leaking. The MOC of the tubes and shell is 1 ¼ Cr ½ Mo. Sweet Naphtha is on tube side and HT shift effluent is on shell side and the exchanger is BES type (TEMA). The tube inlet is provided with an expansion bellow. Request others to share their experience on similar failure and the preventive measures / modifications undertaken to avoid the leaking of the exchanger in the similar service.

 

[apiguy]

If you can isolate this vessel on the fly, you could perform video-borescope or iris of those tubes adjacent to the splash plate in the bellows section. This is a common location for a leaker due to the erosion.

The APIGUY....

 

[dhdsvr]

The reformer effluent contains large quantities of steam condensate and CO&CO2. If any cold areas are there this low pH condensate condenses and attacks the metal. Hence selection of suitable metallurgy that will withstand a pH of 4 will solve the problem. The metallurgy selected should have tolerance to chlorides that will be present in Naphtha.