May I Ask Another Ques? Because I want to know the distribution of component of a non-ideal multicomponent mixture in a distillation column, I had calculated the activity coefficient for a particular multicomponent system at a temperature, lets say 60 C. Thus I can obtain its relative volatility afterwards. The question is would the relative volatility of this substance change or stays approximately the same when the T is being increased or decreased by let's say 30 C , considering that this system is a non ideal VLE system? I am doing this part because I wish to know its overhead temperature and distillate's temperature... If the answer is "No"..I have to recalculate the activity coefficient but this is rather tedious as I am using UNIFAC method to calculate activity coefficient..so can I just assume that the changes in relative volatility is slight upon changes in temperature?