The demand for high-purity gases in modern laboratories is increasing day by day, and nitrogen hydrogen air integrated machines have become an ideal choice to replace high-pressure gas cylinders due to their safety, convenience, and economic characteristics. Its core technology lies in the clever combination of two advanced technologies, pressure swing adsorption (PSA) and proton exchange membrane (PEM) electrolysis, to produce high-purity nitrogen, zero order air, and high-purity hydrogen, respectively.

1、 Pressure Swing Adsorption (PSA): The Art of Separating Nitrogen and Air

The core of the preparation of nitrogen and zero order air is PSA technology. The principle is to utilize the selective adsorption ability of molecular sieves for gas components. Compressed air enters the adsorption tower equipped with carbon molecular sieves, where impurities such as oxygen, water molecules, and carbon dioxide are preferentially adsorbed, while nitrogen molecules are enriched and output as high-purity product gas due to their fast passing speed.

Before the adsorption tower reaches saturation, the system will automatically switch to another tower for adsorption, and the saturation tower will achieve regeneration by rapidly reducing the pressure (the core of "pressure swing"), desorbing and emptying the adsorbed impurities. This dual tower alternating and cyclic working process ensures the continuous and stable production of nitrogen, with a purity of up to 99.999% or higher. Meanwhile, compressed air that has been deeply dried and filtered is directly supplied as zero order air.

2、 PEM electrolysis technology: green preparation of hydrogen gas

The preparation of high-purity hydrogen relies on PEM pure water electrolysis technology. The principle is that under electrified conditions, deionized water undergoes electrochemical reactions in the electrolytic cell. PEM membrane is a solid-state acidic electrolyte that only allows protons (H ⁺) to pass through, while serving as a gas barrier and catalyst support.

At the anode, water molecules are decomposed into oxygen (O ₂), protons (H ⁺), and electrons (e ⁻).

At the cathode: Protons (H ⁺) passing through the PEM membrane combine with electrons (e ⁻) to generate hydrogen gas (H ₂).

The presence of PEM membrane isolates hydrogen and oxygen, thereby directly producing high-purity hydrogen gas (usually ≥ 99.999%). Due to the use of only ultrapure water and the absence of any alkaline solution in the entire process, the hydrogen produced is pure, pollution-free, and the system is safe and reliable.

Conclusion

In summary, the nitrogen hydrogen air integrated machine has achieved efficient separation of nitrogen and purification of air through PSA technology, and green production of high-purity hydrogen gas from pure water through PEM electrolysis technology. The collaborative work of these two core technologies together constitutes a safe and autonomous on-site gas source solution for modern laboratories.