Forming an ice plug inside a high diameter pipeline in stationary water using a nitrogen vapour exhaust restriction

The ice plug isolation technology is used for repair or maintenance activities conducted on large diameter horizontal pipelines without shutting down the entire thermal-hydraulic installation or its water supply. The amount of information useful in dimensioning the ice plug devices as well as on the operating techniques themselves is extremely scarce. The nitrogen vapour exhaust nozzle diameter is arbitrarily chosen; reducing it by 24 % has an important influence on the ice plugging process. Its influence is more or less dependent on the liquid nitrogen injection technique inside the device. The article contains a brief presentation of the experimental technological facilities used, followed by a series of two experiments performed on a 200 mm diameter testing section using stationary demineralized water under similar temperature and liquid nitrogen supply conditions. At the end of the article, there is a brief result analysis and a few conclusions. The paper is dedicated to specialists working in research and technological engineering.