REMOVAL OF DIVALENT SALTS FROM AQUEOUS MEG SOLUTIONS IN A MEG RECLAMATION PROCESS

摘要

Hydrate inhibition with Monoethylene Glycol (MEG) is a well-established means of preventing the formation of hydrates in gas production pipelines. MEG Reclamation technology was developed specifically to recover the MEG for reuse. The term "reclaiming" typically refers to the process of removing water, salts and other dissolved and suspended solids to achieve the required outlet MEG purity. MEG is "regenerated" by boiling off the MEG and water, leaving salts to build up and be removed from the process. Removal of the divalent cations from the incoming MEG/water/salt feed stream is critical due to the high solubility of the divalent cations in MEG. At process conditions this solubility is sufficient to raise the MEG viscosity and hinder removal of the predominate sodium chloride salt from the process. This paper describes the process improvements for removal of divalent salts from aqueous MEG solutions by (i) a continuous process and (ii) a batch process. Two case studies are used to illustrate when to select the appropriate process.