Q & A > Question Details
There is continuous increase and decrease in our column delta pressure in water methanol column. At the same time we noted that our temperature profile of the bottom and middle bed is also fluctuating.
I feel that our column is having vapor cross channeling.
There is some variation in feed flow and steam flow, but column is somewhat running at 100 % load.
If anybody experienced such problem in your plant, please throw some light to understand what causes this fluctuation in delta pressure and temperature profile in the bed and what action to be taken.
Additional information:
Steam direct injection for stripping
There are three bed made of PP intolox saddels
Steam flow is controlled by mid bed temp
Reflux is controlled by feed flow

More information:
This is a packed distillation column to strip methanol from water. We are using steam stripping in our case because there are some traces of Acetic acid in the bottom. To prevent corrosion we have to strip at low temperature, so we are using steam stripping. There is huge variation in temperature profile of the middle bed, at 100 % load First indication of channeling is the change in delta pressure and disturbance in temperature profile. Disturbance in temperature profile is caused by improper distribution of vapor flow in the bed. So thinking this is because of vapor cross channeling.
If it is channeling or flooding how can we deal with it?

More information:
Thanks a lot for all your suggestions, we have opened our tower found that steam deflector plate was installed wrongly, so steam was injecting directly into the packing, which caused packing to expand and that caused channeling in our tower. After rectifying this, now we don't face this problem.
25/04/2011 A: Rajkumar Chate, Sulzer, rajkumar.chate@sulzer.com
Generally vapor distribution is the problem in tray column, in tray column if my flowpath is too big then it may be a chances of vapor channeling and by passing. For your column please check what height is available from vapor feed nozzle to bottom of bottom bed where you have a vapor feed. Steam will be coming at high pressure when it enters in the column it get suddenly expand. once it entered in the column then its momentum need to be broken else there will be a huge entrainment and it will increase the pressure drop. please check the height available for vapor disengagement, this height should be at least 500 mm. if possible have a chimney tray below the bottom bed for vapor distribution.
17/03/2011 A: SUNDEEP GUPTA, PETROCHEMICAL INDUSTRIES COMPANY, sundeep_gupta@pic.com.kw
It is difficult to provide a single answer to your problem. You need to work with your column packing provider on this issue. He will work with the liquid/vapor loads and see how is the loading of the packings.
If still there is no clue, then a gamma scan of the column provides a good picture of what is wrong inside. May be some internal device has a problem, or there is excess liquid built-up in one of the distribution trays.
20/11/2010 A: keith bowers, B and B Consulting, kebowers47@gmail.com
You describe a column that is 'flooding'.
18/11/2010 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
I am assuming this is a distillation column. Conduct a test run by reducing the feedrate to 85% of flood by calculation using the capacity curve for the packing being used. Then describe the operation again to us for comments.
18/11/2010 A: Berthold Otzisk, Kurita Europe GmbH, Berthold.Otzisk@kurita.eu
Without knowing for which plant and purpose the water methanol column is used, it is difficult to annotate something.
The Rectisol process uses such columns and they often suffer with nickel fouling. This results in delta pressure increase, channeling in the bottom section and declined flow characteristics. Kurita developed a chemical cleaning program, which removes the nickel deposits without attacking the metal surface.