Removal of mercury in a gas dehydration process using thermally stable chemical additives

Abstract

The present invention is directed to the removal of mercury in a gas dehydration process using thermally table chemical additives.

What is claimed is: 
     
         1 . A process for removal of mercury in a gas dehydration system comprising (a) adding a complexing agent to a recirculated glycol solvent as part of the glycol solution feed to the dehydration liquid contactor and recirculating continuously with the glycol solvent, (b) selectively reacting the complexing agent with mercury in the wet natural gas to remove the mercury from the dry natural gas product, (c) and feeding the rich glycol with the complexing agent to a regenerator and continuously regenerating. 
     
     
         2 . The process of  claim 1 , wherein the overhead of the regenerator containing water and mercury vapor is contacted with an adsorbent that captures mercury. 
     
     
         3 . The process of  claim 2 , wherein the adsorbent is selected from the group consisting of activated carbon, alumina, silica, zeolite or supported metal. 
     
     
         4 . A process for removal of mercury in a gas dehydration system comprising (a) adding a complexing agent continuously prior to a liquid contactor, wherein inside the liquid contactor, the complexing agent dissolved in the lean glycol solvent selectively reacts with the mercury in the natural gas, producing a rich glycol solvent containing mercury, (b) and the rich glycol solvent is then sent to an adsorber where mercury and the complexing agent are removed using an adsorbent. 
     
     
         5 . The process of  claim 4  wherein the adsorbent is selected from the group consisting of activated carbon, ion-exchange resin, alumina, silica, zeolite or supported metal. 
     
     
         6 . The process of  claim 5  wherein the rich glycol with reduced complexing agent and no mercury is fed to a regenerator to remove water in the overhead and regenerate the glycol solvent. 
     
     
         7 . The process of  claim 4  wherein A filter aid is then added after the liquid contactor, but prior to the expansion valve. 
     
     
         8 . The process of  claim 7  wherein the filter aid is a mechanical filter, carbon filter, ultrafiltration filter or nanofiltration filter.