Cryogenic Air Separation for Nitrogen Production
Cryogenic air separation is a traditional nitrogen production method with a history of several decades. It uses air as the feedstock, which is compressed and purified, then liquefied into liquid air through heat exchange. Liquid air is mainly a mixture of liquid oxygen and liquid nitrogen. Based on the difference in their boiling points (at 1 atm, the boiling point of oxygen is -183°C while that of nitrogen is -196°C), nitrogen is obtained by rectifying and separating liquid air.
Cryogenic nitrogen generation units feature complex equipment, large footprint, high infrastructure costs, and high one-time investment. They also have high operating costs, slow gas production (12–24 hours), strict installation requirements and long installation cycles. Considering equipment, installation and infrastructure, for units with capacity below 3500 Nm³/h, the investment of PSA units of the same specification is 20%–50% lower than that of cryogenic air separation units. Cryogenic nitrogen generation is suitable for large-scale industrial nitrogen production, but uneconomical for medium and small-scale applications.
Pressure Swing Adsorption (PSA) for Nitrogen Production
Compared with traditional nitrogen production methods, PSA nitrogen generation features a simple process flow, high automation, fast gas production (15–30 minutes), low energy consumption, and adjustable product purity over a wide range according to user demands. It also offers easy operation and maintenance, low operating costs and strong adaptability. Therefore, it is highly competitive for nitrogen generators below 1000 Nm³/h, and has become increasingly popular among small and medium-sized nitrogen users. PSA nitrogen generation has become the preferred solution for such users.
Membrane Air Separation for Nitrogen Production
Using air as the feedstock, membrane separation separates oxygen and nitrogen based on their different permeation rates through the membrane under certain pressure.
Compared with other nitrogen generators, it has a simpler structure, smaller size, no switching valves, less maintenance, faster gas production (≤3 minutes) and easy capacity expansion. It is especially suitable for small and medium-sized users requiring nitrogen purity ≤98%, with an excellent cost-performance ratio. However, when nitrogen purity exceeds 98%, its price is more than 15% higher than that of PSA nitrogen equipment of the same specification.
The above is the knowledge about nitrogen generation units compiled and released by Suzhou Jiarui Gas System Co., Ltd., a PSA nitrogen generation manufacturer. We hope this information is helpful to you.
