2 replies to this topic

[Anish Nair]

We are facing a problem in our amine regeneration column where the column level gets empty which results in low Acid gas generation. Suddenly the level builds up after a while and acid gas flow also increases.

 

Here I am suspecting that our trays are getting flooded as the column DP during this period is high. 

 

We are having 23 Valve tray in the column and maximum allowable pressure drop for the column in 0.21 Kg/cm2(g). 

 

Can anyone kindly suggest, if this is tray flooding condition that we are facing and what can be done to rectify the same?

[cea]

Prime-facie, it does not appear any problem with your column operation / column design.

 

The sudden change in level is may be predominantly due to

1) Very low level in column pot

2) Type of level instrument selected (I guess, it is DP (differential pressure) type.)

3) Improper selection of level control valve

 

In case, if the above said problem is recent development, probable cause would be very low level in column pot. This can be justified on account of your statement "...which results in low acid gas generation". Your reboiler may be of any type, it will not deliver desired duty unless there is desired flow through it & hence liberation of absorbed acid gas. You may check circulation flow through reboiler, in case you have got forced circulation through it. To prove this prediction, you may start building-up level in column under manual supervision & observe steady functioning of the column. Accordingly, your level instrument can be calibrated.

 

Just one question - What is status of your utility stream control valve (steam / condensate control valve), when there is no level appear in level instrument. Keep an eye on functioning of this control valve, as it can tell you much about your concern. You can check history trend of its valve opening / flow. This may reverse above finding.

 

Your column pressure drop of 0.21 kg/cm2 (g) for 23 trays is seems to be ok as long as it remains unchanged. Probability of column flooding is expected to be very low.

Edited by cea, 17 June 2016 - 06:40 AM.

[Bobby Strain]

Give little, get little. You won't get much useful help, but lots of speculation without giving information on the system. A P&ID and operating data including duties, flows, temperatures, and pressures over a suitable time period. A drawing showing the internals of the column bottom, with dimensions, would be helpful, too. Along with piping between the column and reboiler, including elevations. Original design data would give a basis for analysis.

 

Bobby