How do you calculate "salt point" of an atmospheric crude distillation tower overhead system containing full boiling range naphtha?
Answers
|
07/12/2009
|
A:
|
Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Best way is to simulate the overhead system using OLI's ionic modeling software. Currently the only salt that it can calculate is ammonium chloride, however. There is an industry JIP that is collecting the necessary thermo data to allow calculation of various amine chloride salt points in the OLI software as well. To get access to this data, however, you need to be a member of the JIP.
The chemical vendors like Baker Petrolite, Nalco and GE also have their own proprietary ionic models and they can estimate salt points for you as well.
I have also curve fit the ammonium chloride equilibrium curve and used that to estimate salt points. You need to estimate the total moles of overhead vapor (hydrocarbon, steam and contaminants) and the total mass of ammonia and chloride so that you can calculate the partial pressure of ammonia and chloride. With that information you estimate the salt point based on the ammonium chloride equilibrium curve. It generally produces salt points that are reasonably close to what the chemical vendor models produce.
|