(1) Cryogenic air separation nitrogen generator
The cryogenic air separation nitrogen generator is a well-established method for nitrogen production with a history spanning several decades. It utilizes air as the feedstock, which undergoes compression and purification before being liquefied via heat exchange, resulting in liquid air that consists mainly of liquid oxygen and liquid nitrogen. By exploiting the discrepancy in boiling points between these two substances (-183°C for liquid oxygen and -196°C for liquid nitrogen at 1 atmosphere), nitrogen is obtained through the rectification and separation of the liquid air mixture. However, this process requires sophisticated cryogenic equipment, occupies a considerable area, entails high construction costs, demands substantial initial investment, incurs significant operational expenses, and has a slow gas production rate (12 to 24 hours). Additionally, it necessitates strict installation requirements and has a lengthy production cycle. Considering all these factors, for nitrogen production equipment below 3500Nm3/h, the investment required for a PSA (Pressure Swing Adsorption) unit with the same capacity is typically 20% to 50% lower than that of the cryogenic air separation unit. While cryogenic air separation is suitable for large-scale nitrogen production in industrial settings, it is less economical and impractical for medium and small-scale nitrogen production applications.
(2) Molecular sieve nitrogen generator
PSA nitrogen production is a cutting-edge technology that has seen significant development since the 1970s. It utilizes air as raw material and carbon molecular sieve as adsorbent to selectively adsorb oxygen and nitrogen. As a result, nitrogen and oxygen are separated, and the process is commonly referred to as pressure swing adsorption. Its numerous advantages include process simplification, high degree of automation, quick gas production (within 15-30 minutes), low energy consumption, and adjustable product purity based on customer requirements. Additionally, its operation and maintenance are convenient, and the overall operating costs are low. As such, this technology has revolutionized the traditional method of nitrogen production.
(3) Membrane air separation nitrogen generator
By utilizing air as a raw material, oxygen and nitrogen can be separated through a membrane that allows for different permeation rates based on each gas's unique properties. This process requires specific pressure conditions to be met. This equipment offers several advantages over other hydrogen production systems, including a straightforward design, compact size, ease of capacity expansion, no switching valve, low maintenance, and quick gas production times (within just three minutes). It is particularly well-suited for small users who require nitrogen purity levels of around 98. However, the price of this equipment will increase by over 15% when nitrogen purity is above 98%, compared to systems with similar specifications, such as PSA nitrogen generators.