Drying method of pipeline 1

[daebakwoo]

Dear ALL.

I am a process manager in my company that is in charge of commissioning natural gas pipeline ranging from 20inch to 36inch.

Since the construction of the pipes, various processes have bees implemented to remove water in the pipes.

First, purging with nitrgen of about 150% of the pipe volume, and puge until the water dew point temperature of -49℃ at atmospheric pressure is reached with natural gas.

Anyway, I have a few questions about purging procedures.


Question 1) As far as I know, there are a few methods to remove water in the pipes(30inch, 18km).

- Continuously blowing nitrogen or natural gas into the pipes
- Opening the discharge valve after filling and pressurizing nitrogen or natural gas in the pipes

Which method is more efficient above ?


Question 2) What is the rated flow or pressure when removing moisture using nitrogen or natural gas?


Thank you

 

[alchemon]

This may be a dumb question... but aren’t you forgetting the pig(s)?

 

[shvet]

Question 1) As far as I know, there are a few methods to remove water in the pipes(30inch, 18km).

- Continuously blowing nitrogen or natural gas into the pipes
- Opening the discharge valve after filling and pressurizing nitrogen or natural gas in the pipes

Which method is more efficient above ?

See AGA Purging Guide for comissioning of natural gas pipelines. Applicable methods for inerting for your case as per AGA:
- inert gas slug
- filling with water
- pigging
Each of these methods has pros and cons. Continuous blowing and pressure swing are not the best options as high consumption of inert gas. For calculation of inert gas consupmtion during continuous blowing and pressure swing see CEN/TR 15281.

 

[shvet]

Sorry for incorrect reply. For drying see chapter 6 McAllister's Pipeline Rules of Thumb Handbook.