Hi nellcris,
the major factors to improve are :
1.Circulation rate of solvent (increase)
2.Temperature (decrease)
3.Gas Pressure(decrease)
I need more information of the design values,and how near is your operation to specification..you may also have a heat xchange or pump capacity problem
E-mail me at wayil@hotmail.com ,no fees consultation!!
Good luck,
whylie