Purification Unit

Purification Unit is skid mounted with the following components-

• After Coolers -This is cylindrical tank fitted with air coils. The air is cooled after passing from compressor and cooled by circulating water.
• Cascade Coolers -This is elliptical tank fitted with air coils. These coils are half submerged in water, dry nitrogen bubbled through this water to become wet gas. As water vaporizes water gets cooled. The air inside the pipe will get cooled.
• Chilling Tank and Chilling Unit-Chilling tank is cylindrical tank fitted with air coil and refrigeration coils. The water is cooled by chilling unit and refrigeration coils. In this unit air is further cooled.
• Moisture Separators used in Oxygen Gas Plants-Two numbers of moisture separators provided one after the after cooler and second one after chilling tank .The moisture condensed as water will be separated and drained regularly.
• Oil Adsorber -Oil adsorber is packed with activated alumina balls . Here the oil Vapour carried over by compressor will be removed. It is desirable to drain moisture from the bottom of the oil adsorber at regular intervals and also change the alumina after a specified time frame.
• Molecular Seive Driers-It is twin vessel driers both are filled with molecular sieves. As the process air passes through molecular sieves, the molecular sieves adsorb water vapour and carbon - di- oxide (Co2) from the air and make the air dry. After about 10 hours the molecular sieves become saturated and it will have to be regenerated by blowing hot air or nitrogen. Once the hot gas is blown through the saturated molecular sieves the CO2 and water vapour discharged and the drier is ready to use again.
• Dust filter:Dry air is filtered in this unit by a special material and prevents any dust particles entering the air separation unit.
• Defrost Heater for oxygen plants-Despite purification and filtration of air some water vapour and CO2 will get past the molecular sieve driers and enter the Air separation unit and may be deposited in the tubes of heat exchangers, valves and L.O. pump filters. To remove this deposit, defrosting of the plant is carried out. For this dry air after heating in defrost heater passed inside the air separation unit and L.O. pump and deposits will be melted and removed.