The operator of the Merox™-type treating unit in Exercise 15.1 notices that the caustic slowly loses strength over time. Analysis of the spent caustic shows levels of Na2CO3. The inlet NGL has been...

The operator of the Merox™-type treating unit in Exercise 15.1 notices that the caustic slowly loses strength over time. Analysis of the spent caustic shows levels of Na2CO3. The inlet NGL has been washed with an MEA solution and does not contain CO2. What is the source of the CO2 that is reacting with the circulation caustic solution?

Exercise 15.1

Using Equation 15.1, how much 15% by weight caustic (molar mass = 40) solution must be circulated (lbm/h, kg/h) to remove 22 lbm/h (10 kg/h) of methyl mercaptan (molar mass = 48) from an NGL mixture?