CONTROL OF TOP OF LINE CORROSION BY CHEMICAL TREATMENT

摘要

Top of line corrosion (TLC) takes place in wet gas lines as a result of heavy water condensation due to extemal cooling of the pipe by river water or seawater. The presence of organic acids in the produced water, mainly acetic acid (HAc), was confirmed in field cases where severe TLC was observed. In fact, the rate of internal localised corrosion was significantly influenced by the presence of HAc as the corrosion product is very soluble in water and the pH is generally low. In order to control TLC in such cases two types of treatments were envisaged: continuous injection of neutralising chemicals and regular batch treatments using diluted corrosion inhibitor between two pigs. Special pigs could be used to film the top of the line either using concentrated inhibitor or inhibited water available at the bottom of the line. This paper summarises the results of various studies on the selection of filming inhibitors for batch treatment, on the batch treatment operation of gas lines and on the use of a neutralising amine to control the HAc acidity.