System and Process For Removal Of Organic Carboxylates From Mono Ethylene Glycol (MEG) Water Streams By Acidification and Vaporization Under Vacuum

Abstract

A system and method for removing organic carboxylates from a mono ethylene glycol (“MEG”) stream includes a reaction vessel; means for cooling and diluting the MEG stream being routed to the reaction vessel; means for acidifying the cooled and diluted MEG stream during its residence time within the reaction vessel; and means for removing an acetic-rich overhead stream from the reaction vessel. The acidification of the cooled and diluted MEG stream occurs under a vacuum. The reaction vessel may be located downstream of a calcium removal vessel and receive a filtered bottom stream from that vessel, or it may be a single reaction vessel that cycles between a calcium removal mode and an acetate removal mode, with the pressure of the single vessel being greater during the calcium removal mode than during the acetate removal mode.

What is claimed: 
     
         1 . A system for removal of organic carboxylates from a mono ethylene glycol (“MEG”) stream, the system comprising:
 a reaction vessel; 
 means for cooling and diluting the MEG stream being routed to the reaction vessel; 
 means for acidifying the cooled and diluted MEG stream during its residence time within the reaction vessel; and 
 means for removing an acetic-rich overhead stream from the reaction vessel; 
 
       wherein the acidification of the cooled and diluted MEG stream occurs under a vacuum. 
     
     
         2 . A system according to  claim 1  wherein the reaction vessel includes an acetate removal mode and a calcium removal mode, the reaction vessel including means for alternating between the above mentioned modes, the pressure of the reaction vessel being greater during the calcium removal mode than during the acetate removal mode. 
     
     
         3 . A system according to  claim 1  wherein the reaction vessel is located downstream of a calcium removal vessel within a MEG recycle loop and receives a bottom stream from the calcium removal vessel. 
     
     
         4 . A system according to  claim 1  further comprising means for raising the alkalinity of the cooled and diluted MEG stream during its residence time within the treatment vessel. 
     
     
         5 . A system according to  claim 4  wherein the raising alkalinity means is selected from the group consisting of sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide. 
     
     
         6 . A system according to  claim 1  further comprising means for removing a calcium-rich bottom stream from the reaction vessel. 
     
     
         7 . A system according to  claim 1  wherein the reaction vessel is at a pressure in a range of 0.1 to 0.3 bar. 
     
     
         8 . A system according to  claim 1  wherein the acidifying means results in the cooled and diluted MEG stream during its residence time within the reaction vessel having a pH in a range of 3.5 to 5.5. 
     
     
         9 . A system according to  claim 1  wherein the acidifying means is hydrochloric acid. 
     
     
         10 . A system according to  claim 1  wherein the cooled and diluted MEG stream is below 80 wt % MEG. 
     
     
         11 . A system according to  claim 10  wherein the cooled and diluted MEG stream is about 50 wt % MEG 
     
     
         12 . A system according to  claim 1  wherein the cooled and diluted MEG stream is at a temperature in a range of 80° to 100° C.