Q & A > Question Details
Sometimes it is seen that the leaky tube of heat exchanger is used by plugging both sides. I want to know the percentage of tubes that can be used in plugged condition in running condition and also the standard for this plugging.
03/01/2017 A: RAMAKRISHNA DADI, HMEL, dadi2rama@gmail.com
We found many tube leaks in cooling water tube side exchanger due to low velocity to fouling the tubes and corroded.we normally refinery condition maximum is 10-12% can only allowed otherwise you need to throughput reduction required like flow also reduced. second time we found more cross to 15% we procure new tube bundle to replace for next heat exchanger leak or opportunity condition.
My suggestion for cooling water exchangers back flush sequence weekly to minimize the tube fouling.
We found recently recycle gas preheater exchanger tubesheet is alloy P11 but we never observed any tube leaks but after we found after 5 years tube sheet is corrosion/erosion found in tubesheet. So i strongly recommends any heat exchanger minimum 2-3 years need to open and hydro jetting for increase the life
10/11/2010 A: Vivek Jain, Panipat Refinery, Indian Oil Corporation Limited, vivek265@gmail.com
Normally 20% per pass is the maximum limit of the tubes which can be plugged.
06/04/2010 A: Mike Watson, Tube Tech International Ltd, mike.watson@tubetech.com
Typically shell and tube exchangers are built overcapacity of about 30%. As a global cleaning / inspection specialist we have found up to 30% plugged whether it be due to blockages that cannot be cleaned or leaky tubes. We are developing an On-Line Cleaning system for Shell and Tube Exchangers during full production at 20 bar and 300 degrees C. This will ensure tubes are less likely to corrode or erode as the tubes will be kept clean all the time.
03/04/2010 A: Balasubramanian Iyer, Nexen CNOOC Limited, balasubramanian.n@aol.in
Approximately about 9% of the tubes can be plugged. And if still more than 9-10% tubes are to be plugged then one can just do some calculations for the heat transfer and check that the required heat transfer is achieved or not. Generally if conditions arise for more than 10% of tubes to be plugged then it is better to go for tube replacement to have same heat transfer efficiency.
03/04/2010 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
The percentage of tubes plugged is typically limited by the extent of heat duty loss you can tolerate. I have never seen more than 25%. I don't know of a standard or correct procedure for the plugging operation. Obviously, if it is not done well, there will eventually be leaks again.