What happen after breakthrough occur?? 1

We adsorp moisture from nat. gas from 40 lb/MM to 0.1 lb/MMscf. Vendor suggest life time = 4 yrs., but we scare that breakthrough 'ld happen before design-life.
What happen when breakthrough occur?? Somone said moisture will be increased so fast and has water (liquid) in outlet gas? Is it true ? How do you control or design to change bed? also does it longer or shorter than vendor design ? Bad luck is we don't have moistue probe along vessle.

 

[TD2K]

You will not get liquid water downstream of the bed unless the you cool the gas below its dewpoint. Think about it.

When a bed reaches breakthrough, the outlet water content will fairly quickly approach the inlet water content, the amount of time depends on the mass transfer zone.

To monitor our beds, we used to record for each cycle the flow rate through the bed and the time to breakthrough and use that to determine how the bed's performance was deteriorating with time. As our inlet temperature/pressure was very stable, we didn't need to adjust for changes in the inlet gas water concentration but that might be another variable you need to monitor. The 'performance curve' was linear so we could project fairly comfortably how the bed was going to continue to perform.

Basically, you need to plan to replace the bed before the adsorbtion time reaches the time it takes to regenerate the off-line bed OR the pressure drop across the bed becomes limiting. The vendor's life span is just an estimate, it's not a 'must change' date.