Application Note Trace Moisture Measurement in Air Separation Units Air Separation Units (ASUs) are critical in industries that require high-purity gases such as oxygen, nitrogen, and argon. Accurate dewpoint measurement plays a vital role in ensuring the e ciency, safety, and reliability of these units. This application note outlines the signi cance of dewpoint monitoring in ASUs, common moisture-related challenges, practical solutions, and references to key standards. What are Air Separation Units? ASUs are industrial plants designed to separate atmospheric air into its primary components — nitrogen, oxygen, and argon — using cryogenic distillation or non-cryogenic methods. These gases are essential for applications in steel manufacturing, healthcare, electronics, and chemical processing. Key Functions of ASUs: Cryogenic Distillation: Air is cooled to extremely low temperatures, lique ed, and then separated based on boiling points. Non-Cryogenic Methods: Techniques like pressure swing adsorption (PSA) or membrane separation are used for speci c purity requirements. How Does an Air Separation Unit Work? The most common method used is cryogenic distillation of air. The principle is simple: air is cooled to very low temperatures so it can be lique ed and then separated based on boiling points. WASTE NITROGEN WASTE NITROGEN DISTILLATION COLUMN MAIN HEAT EXCHANGER (LIQUIFICATION OF THE AIR) EXTERNAL PRODUCT COMPRESSION

Application NoteTrace Moisture Measurement in Air Separation UnitsStep by Step ASU Process Compression: In this stage, atmospheric air is drawn into the ASU and passed through a series of compressors to increase its pressure. The purpose is to make the subsequent cooling and separation processes more efficient, with typical pressure ranges going between 5 and 10 bar gauge. Purification: Before further processing, the compressed air is typically purified to remove impurities (including moisture, carbon dioxide, or trace contaminants). This step ensures that the separated gasses are of high purity...

Application NoteTrace Moisture Measurement in Air Separation Units Moisture Problems in Air Separation Units Moisture is a critical contaminant in ASUs. Even trace amounts can cause significant operational issues: • Freezing Blockages: Water vapour can freeze at cryogenic temperatures, leading to blockages in heat exchangers and distillation columns. • Corrosion: Moisture accelerates corrosion of internal components, reducing equipment lifespan. • Product Purity: Excess moisture compromises the purity of separated gases, affecting downstream processes and product quality. • Safety Risks: Ice...