Drying of vessel after pressure test

Date 03-11-2016 21:44

Open the manway, handhole, or inspection point and have a look. Use a borescope if necessary. How are you blowing the hot air through?

By Superflux (****)

Date 03-11-2016 23:10

Need a calibrated dewpoint meter if this a critical dry for something like anhydrous ammonia.
Or, you can find a portable meteorology device for cheap if you just want peace of mind.

http://www.cabelas.com/catalog/product.jsp?productId=1744944&type=product&MDK=dynbanP_DOb&MDC=cat104788080

By Sambuddha (*)

Date 03-15-2016 05:45

Here in Kolkata India in summer temparature is about more than 40 C with relative humidity some times more tha 90% .With use of Hygrometer if i found no change in relative humidity for a certain amount of time ,then is it ok

By Trackergd (**)

Date 03-15-2016 12:27

Sambuddha, Is there a particular specification you are working to? What is going into the tank? Might help if we had a few more details. My concern is that the relative humidity (90%) might be higher than the specification or might react with what is going into the tank.

By Sambuddha (*)

Date 03-18-2016 07:33

Actually I have to dry a Air Cooled Heat Exchanger and it will go by sea and may take 1 month of sailing.It will be purged with Nitrigen after drying at 0.25Kg/cm2 pressure

By Trackergd (**)

Date 03-18-2016 14:09

OK, that is a bit more clear.

In a former life working for Kidde, I inspected code pressure vessels (post code inspection at manufacturer) used for dry chemical systems. We would run heat in them for a couple of days, then seal them up with a humidity sensor inside to ensure they were dry. It's been about 10 years, but if memory serves me well, the spec was about 20% humidity. We would then remove the sensor, drop in a large desiccant pack for transport to our main plant. The change in temperature and humidity from Port Arthur Texas to winter in Pennsylvania was sometimes rather dramatic.

Hope this helps.