Regenerating hydration inhibitor solution, for use in transporting natural gas comprises distilling and contacting with ion-fixing solid to reduce water and ion contents

摘要

#CMT# #/CMT# Regeneration of a solution (A) of a hydration inhibitor (I), to obtain a solution depleted in water and ions, involves: (a) distilling (A) to reduce its water content; and (b) contacting at least part of (A) with ion-fixing solid(s) (II), to reduce its ion content. #CMT#USE : #/CMT# (I) is used as a hydration inhibitor in the transport of natural gas, for preventing blockages of pipelines due to hydrate formation. The process is specifically part of an overall process in which (A), depleted in water and ions, is contacted with crude natural gas; the mixture of (A) and natural gas is transported by circulation through a pipeline; and (A), loaded with water and ions, is separated from the natural gas (claimed). #CMT#ADVANTAGE : #/CMT# Treatment with (II) (specifically incorporated in a column) markedly reduces the salt content of (A), without the need to remove corrosion inhibitors (such as MDEA) present in (A). Consumption of the corrosion inhibitors is thus greatly reduced. #CMT#CHEMICAL ENGINEERING : #/CMT# Preferred Process: (I) is methanol or mono-, di- or triethylene glycol. (II) fixes anions or cations, and (A) is optionally also contacted with a further (II) fixing cations or anions respectively. The anion-fixing (II) is selected from anion-doped zeolites, silicas, aluminas, clays and resins; or is a basic compound. The cation-fixing (II) is selected from proton-charged zeolites, silica-aluminas and synthetic resins; or is a fluorinated alumina, chlorinated alumina or clay. (A) is contacted with (II) at atmospheric pressure to 100 bars and 0-500[deg]C. #CMT#EXAMPLE : #/CMT# 100 g of dealuminated zeolite HY powder (Si/Al ratio 48) was activated by calcination under nitrogen (10 Nl/h) at 350[deg]C overnight, then placed in a reactor and heated to 80[deg]C. A conventional monoethylene glycol-based hydration inhibitor was passed through the reactor at 0.1 ml per minute. The charge had pH 9, sodium ion content 1018 ppm, calcium ion content 145 ppm, magnesium ion content 58.5 ppm and total ion content 1219.5 ppm, whereas the effluent had pH 2, sodium ion content 50 ppm, calcium ion content 10 ppm, magnesium ion content 3 ppm and total ion content 63 ppm.