5 replies to this topic

[processji]

Can someone support me on the following.

 

Does drying a process system(pipes and vessels) with Nitrogen at 40 deg c and 19 barg take more time compared to dry out using natural gas at 40 deg c and 19 barg.

 

Thanks

Regards

 

 

 

 

 

 

[Bobby Strain]

You should be able to determine this if you are a Chemical engineer.

 

Bobby

[processji]

Bobby

Thanks. Let us wait for response for response from Chemical Engineers.

Regards

[Lavi]

Strange question. I wonder why I can't think like you guys!

 

Well, I believe the time required shall depend on the concentration of water (vapour) present in the purge gas.

Assuming that we have technologies that can give us 100% pure Nitrogen and Natural Gas, the time required to dry out must be the same.

 

Frankly speaking, my experience tells me I have not used Nitrogen for a dry out purpose. I have used it for purging oxygen and others out of my line but not for drying. Nitrogen is then followed by Natural Gas which is used for bone drying.  

 

Please find attached a calculation sheet which shows approximate time required to purge oxygen out of the line.

I guess this will give you a clue.

 

 

Attached Files

•  Purge Time Calculation.xlsx   10.08KB   42 downloads

[Steady]

Nitrogen has specific gravity marginally less than 1 at the given conditions and it can hold more water content than air to get to the saturation. I think, theoretically, one can say that nitrogen may take less time to dry a process system than air.

Edited by Steady, 08 January 2014 - 03:50 AM.

[Babu Prasad]

As stated by Lavi, it supposes to take same time if both gas used same quantity & quality. Practically, drying with natural gas will be faster as quantity of gas availability for purging will be more and economically it will be cheaper than N2. Once the equipment is made oxygen free with N2, it is better to use natural gas for dry out if time is short. Otherwise, if time is not constrain and Nitrogen availability is more, then purging with N2 will be ok  as it will be safer to blow into atmosphere.