The circulation rates for amine systems can be determined from the acid gas flow rates by selecting a solution concentration and an acid gas loading.
The following equations can be used:
For design, the following solution strengths and loadings are recommended to provide an effective system without an excess of corrosion:
For the recommended concentrations the densities at 60°F are:
20% MEA= 8.41 Ib/gal = 0.028 mole MEA/gal
35 % DBA = 8.71 Ib/gal = 0.029 mole DEA/gal
Using these design limits, Equations 7-24 and 7-25 can be simplified to:
The circulation rate determined with these equations should be increased by 10-15% to supply an excess of amine.