The air we breathe contains two gases that are extremely useful in industry: oxygen (about 21%) and nitrogen (about 78%). Adding oxygen to a process enables better control of heating patterns, higher furnace efficiencies (for lower fuel consumption) and reduction in particulate and NOx emissions. It’s used with fuel gases to enhance processes including gas welding, gas cutting, oxygen scarfing, flame cleaning, flame hardening and flame straightening. Oxygen is a raw material in many oxidation processes and to regenerates catalysts. Nitrogen gas is used for purposes ranging from inerting and purging to flushing and sterilizing to product transfer and packaging. Many such processes remove undesirable oxygen from a manufacturing process or environment, preventing oxidation that can damage metal parts and sensitive electronics. Nitrogen is also used in refining and gas separation processes. Since oxygen and nitrogen occur together in the air, they must be separated before they can be used. The right tool for the job is an oxygen generator or a nitrogen generator.
How an Oxygen plant works
Oxygen molecules are separated from the other molecules within a clean, dry compressed air stream. Pressure Swing Adsorption (PSA) is a simple, reliable and cost-effective technology that enables continuous, high-capacity oxygen flow at the desired level of purity (90% to 95%). Adsorption happens when atoms, ions or molecules from a substance (compressed air in this case) adhere to a surface of an adsorbent. PSA technology isolates oxygen molecules from other molecules (nitrogen, CO2, water vapor and trace gases) to leave high purity oxygen at the outlet of the generator. The process takes place in two separate pressure vessels (tower A and tower B), each filled with a carbon molecular sieve, that switch between a separation process and a regeneration process.
How a Nitrogen generator works
Nitrogen molecules are separated from other molecules within a clean, dry compressed air stream. Pressure Swing Adsorption technology is used here as well, to isolate nitrogen molecules from other molecules in compressed air to leave nitrogen at the desired purity at the outlet of the Nitrogen plant. For some applications, such as tire inflation and fire prevention, relatively low purity levels (between 90% and 97%) are required. Other applications, such as food/beverage processing and plastic molding, require higher levels of purity (from 97% to 99.999%).
RO and DI filters use different physical reactions to clean water. Reverse Osmosis (RO) is used to partially clean-up tap water to make it roughly 90% to 99% pure. Deionization (DI) filters exchange positive hydrogen and negative hydroxyl molecules for positive and negative contaminant molecules in water. DI filtering and other processes are sometimes referred to as "water polishing."
Understanding the difference between reverse osmosis (RO) and deionized (DI) is important when identifying the right water purification unit for your lab. Having access to high quality water is essential for laboratories to carry out their daily processes and workflows. By taking a closer look at different methods of producing both types of water, RO and DI, you can feel confident in your decision regarding water purification systems.