Precautions for selection of hydrogen analyzer in electrolytic water oxygen
Hydrogen in oxygen analyzer And the application of oxygen in hydrogen analyzer in electrolytic water hydrogen production industry: no matter what kind of hydrogen production method, to meet the use requirements, it needs to reach a certain purity, so how to judge whether the hydrogen is up to standard? This requires the use of gas analysis instruments to detect the purity of hydrogen. The purity of hydrogen produced by electrolysis of water to produce hydrogen is higher (more than 99.9%), which is far higher than other methods of hydrogen production. Therefore, most places using hydrogen use electrolysis of water to produce hydrogen equipment. However, once the oxygen generated by the electrolysis of water for oxygen production exceeds a certain ratio with oxygen, an unavoidable dangerous accident will occur, so the equipment for electrolysis of water for oxygen production generally requires hydrogen in oxygen analyzer and Oxygen analyzer in hydrogen , which is used to monitor the content of hydrogen and oxygen online in real time.
Hydrogen production by electrolysis of water refers to the dissociation of water molecules under the action of direct current to generate oxygen and hydrogen, which separate from the anode and cathode of the electrolytic cell. According to the different membrane materials of electrolyzer, it can be divided into three technical routes: alkaline electrolysis (AWE), proton exchange membrane (PEM) electrolysis and solid oxide (SOEC) electrolysis. Proton exchange membrane (PEM) water electrolysis for hydrogen production: PEM water electrolysis for hydrogen production selects proton exchange membrane with good chemical stability, proton conductivity and gas separation as solid electrolyte, which can effectively prevent electron transfer and improve the safety of the electrolytic cell. PEM(Proton exchange Membrane) is the abbreviation of proton exchange membrane electrolysis of water to produce hydrogen technology. Different from alkaline water electrolysis hydrogen production technology, PEM water electrolysis hydrogen production technology uses proton exchange membrane as solid electrolyte instead of membrane and liquid electrolyte (30% potassium hydroxide solution or 26% sodium hydroxide solution) used in alkaline electrolyzer, and uses pure water as raw material for hydrogen production gas from electrolytic water, avoiding potential alkaline pollution and corrosion problems.
Schematic diagram of PEM electrolyzer for hydrogen production
Alkaline (AWE) electrolytic water hydrogen production: The membrane of alkaline electrolytic water hydrogen production electrolyzer is mainly composed of asbestos, which is used to separate gas. Alkaline electrolyzed water has a large scale and a high degree of commercialization. Although its structure is simple, its technology is mature, and its cost is low, its efficiency is low, its performance is poor, and its asbestos diaphragm has some defects such as environmental pollution.
Solid oxide (SOEC) electrolytic water hydrogen production: solid oxide is used as electrolyte material for solid oxide electrolytic water hydrogen production, and the operating temperature is 800~1000 ℃. The electrochemical performance of the hydrogen production process is significantly improved and the efficiency is higher, but its disadvantages such as high temperature conditions and slow startup limit its application prospect.
Precautions for selection of hydrogen analyzer in electrolytic water oxygen:
1. Hydrogen concentration in oxygen of electrolytic water Analyzer The measuring range is generally between 5000ppm-5% Vol Very high precision Thermal conductivity principle of 。
2. Since the hydrogen flow generated by PEM proton membrane is very small, it is necessary to select a hydrogen in oxygen analyzer with very fast response time. However, the response time of the hydrogen in oxygen analyzer based on electrochemical principle is generally about 30 seconds, which is not suitable for the occasions with small sample gas flow.
3. The stability of the hydrogen in oxygen analyzer should be very good. Generally, the zero reading should be verified once every 5-6 months without frequent calibration. In the life cycle of the analyzer, in most cases, there is no need to conduct full range calibration, save tedious verification and calibration processes, and there is no need to replace the sensor periodically.
4、 Hydrogen in oxygen analyzer It can effectively prevent condensate water and micro particle pollution, thus protecting the hydrogen in oxygen analyzer and the oxygen in hydrogen analyzer, and obtaining accurate measurement values.
5、 Oxygen analyzer in hydrogen The service life of hydrogen analyzer in oxygen is generally 8-10 years; From the perspective of the whole life cycle, the analyzer The cost of ownership is relatively low.
6. The pretreatment system of hydrogen in oxygen analyzer shall be configured. When electrolyzing water to produce hydrogen, hydrogen flows out of the electrolytic cell, and the measured sample gas (oxygen and hydrogen) is saturated with liquid water, with high humidity, and even liquid water. This requires the pre-treatment device to perform gas-liquid separation, multiple drying and particle filtration on the gas, Fully dry the tested sample gas The measured sample gas can enter the analyzer for hydrogen concentration measurement only when it is dry and clean.
7. For alkaline electrolyzed water, the gaseous gel of lye must be removed during gas pretreatment, otherwise lye will enter Hydrogen in oxygen analyzer or oxygen in hydrogen analyzer , damage the instrument.
