As a key equipment in laboratory and industrial fields, the hydrogen purification technology of the hydrogen air integrated machine directly determines the reliability of gas supply. The current mainstream technology focuses on proton exchange membrane (PEM) electrolysis of water to produce hydrogen, combined with multi-stage purification processes, achieving a breakthrough in hydrogen purity of ≥ 99.999%.
1、 Core purification technology: synergistic effect of PEM electrolysis and catalytic deoxygenation
The PEM electrolysis cell uses perfluorosulfonic acid proton exchange membrane as the electrolyte, with an ion conductivity of up to 0.1S/cm, which can efficiently separate hydroxide ions. Under the action of a direct current electric field, water molecules are oxidized at the anode to produce oxygen, while hydrogen ions penetrate the membrane layer and are reduced to hydrogen gas at the cathode. This process does not require the addition of strong alkaline solutions such as KOH, avoiding the corrosive pollution problem of traditional alkaline electrolysis cells. For example, PeakScientific's Genius series equipment has improved the hydrogen production rate to 99.999% purity by optimizing the membrane electrode structure, while reducing energy consumption to 4.5 kWh/Nm ³.
To further remove residual oxygen, the system integrates a catalytic deoxygenation module. When hydrogen gas flows through a deoxidizer loaded with platinum based catalyst, trace amounts of oxygen react with hydrogen gas to generate water vapor, with the reaction equation being 2H ₂+O ₂ → 2H ₂ O. This reaction occurs at 200-300 ℃, and with the help of explosion-proof electric heating components and dual temperature sensors, the reaction temperature can be accurately controlled to ensure that the oxygen content is reduced to below 1ppm.
2、 Purity maintenance plan: three-level drying and intelligent monitoring system
Pre cooling and drying: Hydrogen gas first passes through a spiral tube gas cooler, which uses circulating cooling water to reduce the temperature to 10-15 ℃, condensing most of the water vapor into liquid water, which is discharged through a gas water separator.
Molecular sieve adsorption: 5A type molecular sieve is used as the adsorbent, with a pore size of 0.5nm, which can selectively capture water molecules and impurities such as CO ₂. The equipment is equipped with a dual tower alternating regeneration system. When one tower is saturated with adsorption, the other tower is regenerated by blowing 180 ℃ hot nitrogen gas to ensure continuous output of dry hydrogen gas with a dew point ≤ -70 ℃.
Terminal filtration: Hydrogen gas ultimately flows through a 0.01 μ m polytetrafluoroethylene (PTFE) filter, which can intercept particles with a diameter ≥ 0.01 μ m and meet the gas requirements of high-precision instruments such as ICP-MS.
The intelligent monitoring system collects real-time parameters such as pressure, flow rate, and purity through high-precision sensors. When the oxygen content exceeds 2ppm or the dew point is higher than -65 ℃, it automatically triggers an alarm and starts the backup purification module. For example, the Anyan nitrogen hydrogen air integrated machine controls the fluctuation range of hydrogen purity within ± 0.05% through PID adjustment algorithm, ensuring the baseline stability of gas chromatography analysis.
3、 Technological breakthrough: anti fluctuation design and long-life maintenance
In response to the intermittent characteristics of renewable energy hydrogen production, modern hydrogen air integrated machines adopt a three tower energy-saving adsorption process, and achieve stable operation within the load range of 10-110% through variable control of high-precision instrument valves. For example, in the photovoltaic hydrogen production project, the Linuo hydrogen purification device can cope with 0-100% power fluctuations and maintain pressure for more than 48 hours after gas shutdown.
In terms of equipment maintenance, the replacement cycle of molecular sieves has been extended to 3 years. Through online monitoring of adsorbent pressure drop and effluent rate, replacement needs can be alerted in advance. The electrolytic cell adopts titanium based platinum plated electrodes, which improve corrosion resistance by 50% and have a lifespan of over 80000 hours, significantly reducing the total lifecycle cost.