range of turndown ratio for absorber

[Tamer123]

dear gents
i would like to konw what is the range of absorber turndown ratio, it is trayed one 20 tray withe normal feed gas 700Knm3/h and amin circulation is 90 M3/h, our plant have proplem in startup with 125 Knm3/h always we have CO2 off-spec ( grater than 100 ppm ) what can we do ? lower or higer the feed ?

 

[joerd]

Please read FAQ731-376, particularly item 5, first. Then, make up your mind in which forum to post. Thank you.

Cheers,
Joerd

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[dcasto]

Without going through tray hydraulics, running an absorber below 50% of design will start seeing lower recoveries. By 30% design rates all the extra trays (again some amines can get by with 15 trays at peak effiencies and proper weir heights for kenetics) and higher residence times.

Get your feed up to over 40% and make sure your amine rate is at least 50% of design. To find you exact minimums would take complete tray specifications, the exact amine compositions and exact gas compositions. Of course temeratures and pressures would have to be known and data to support your lean amine loading.