TABLE OF CONTENTS When I discuss a process problem, I ll frequently qualify my views by stating, Let s assume equilibrium conditions have been reached. What I m doing is choosing to ignore the effect of time on changes in composition. I m ignoring the effects of kinetics on the process. I ll make such assumptions to simplify complex discussions. It s a bad habit, which sometimes gets me into trouble.
A reaction that is limited by equilibrium is finished. Waiting longer will make no difference. An example of this is the absorption of H 2S from refinery fuel gas into an amine solution. Depending on the concentration of the H 2S in the fuel gas, the amine solution will become saturated with H 2S. Mixing the fuel gas and the amine solution for a longer period of time will not push more of the H 2S into the amine solution. The reaction is complete, and we say the absorption of H 2S by amine is limited by equilibrium.
On the other hand, a reaction that is limited by kinetics is not finished. Waiting longer will help to complete the reaction. An example of this is the absorption of CO 2 from refinery fuel gas into an amine solution. The CO 2 will react with the amine to produce a stronger chemical bond than would the H 2S and amine. CO 2 reaction with amine goes slower than the H 2S reaction with...
