Process for rejuvenating used alkanolamaine solutions

A method for increasing the AACI of an aqueous diethanolamine solution being at least partially deactivated from contact with an acid gas, said regeneration method comprising:

• (a) filtering said aqueous diethanolamine solution to remove suspended particulates;
• (b) contacting said filtered aqueous diethanolamine solution with an anionic ion-exchange resin;
• (c) contacting said aqueous diethanolamine solution with a cationic exchange resin;
• (d) reacting said aqueous diethanolamine solution with hydrogen in the presence of a hydrotreating catalyst under hydrotreating conversion conditions of temperature from 30.degree. C. to 400.degree. C., liquid hourly space velocity of from 0.1 hr.sup.-1 to 100 hr.sup.-1, pressure of from 1 to 14,000 kPa, hydrogen dosage from 1 to 100 mols H.sub.2 per mol of diethanolamine, and contact time sufficient to evolve a product stream having a higher concentration of diethanolamine that said at least partially deactivated diethanolamine solution.

A process for removing at least one of H.sub.2 S, CO.sub.2 and CO from a hydrocarbon gas stream containing the same comprising the steps of:

• (a) providing a hydrocarbon gas stream containing a recoverable concentration of H.sub.2 S, CO.sub.2 or CO;
• (b) contacting said hydrocarbon gas stream of step (a) with an aqueous alkanolamine solution containing alkanolamine to remove H.sub.2 S, CO.sub.2 or CO from said hydrocarbon gas stream, to convert at least a portion of said alkanolamine to degradation products having a lesser affinity for sorbing acid gases than said alkanolamine, and to evolve an alkanolamine solution enriched in H.sub.2 S, CO.sub.2 or CO;
• (c) stripping H.sub.2 S, CO.sub.2 or CO from said enriched alkanolamine solution of step (b) to evolve a lean alkanolamine solution containing both alkanolamine and said alkanolamine degradation products;
• (d) heating at least a portion of said lean aqueous alkanolamine stream of step (c) to elevated temperature and holding said lean aqueous alkanolamine solution of step (c) at said elevated temperature under hydrogen pressure in the presence of a hydrotreating catalyst for a period of time sufficient to rejuvenate said lean alkanolamine solution such that the rejuvenated lean alkanolamine solution exhibits increased acid gas sorption capacity per unit mass than stripped lean alkanolamine solution of step (c).