Electrolytic water hydrogen generatorBy electrolyzing pure water to produce hydrogen, the quality of the incoming water directly determines the gas production efficiency, hydrogen purity, and service life of the equipment. Whether it is laboratory gas chromatography carrier gas preparation or industrial fuel cell hydrogen supply scenarios, if the impurities in the influent exceed the standard, it can lead to a decrease in electrolysis efficiency and fluctuations in hydrogen purity, and in severe cases, it can cause faults such as electrolytic cell scaling and electrode corrosion, increasing operation and maintenance costs. Therefore, establishing strict requirements for the quality of incoming water and establishing a scientific water quality control system are the core prerequisites for ensuring the stable operation of electrolytic water hydrogen generators.

The purity of the influent is the core indicator, quantified by electrical resistivity or conductivity. Different types of electrolytic cells have significant differences in purity requirements. Proton exchange membrane (PEM) electrolysis cells require an inlet water resistivity of ≥ 10M Ω· cm (25 ℃) and corresponding conductivity of ≤ 0.1 μ S/cm due to the sensitivity of membrane materials to impurities, and must meet the laboratory's first level water standard; Traditional alkaline electrolysis cells have slightly wider requirements for water quality, but also require a resistivity of ≥ 1M Ω· cm and a conductivity of ≤ 1 μ S/cm. If the purity of the incoming water is insufficient, the electrolyte in the water will increase conductive interference, leading to an increase in electrolysis power loss - taking a 100L/min generator as an example, when the incoming water resistivity decreases from 10M Ω· cm to 1M Ω· cm, energy consumption will increase by 5% -8%, and it will also accelerate the decay of the proton exchange membrane, shortening its service life.

The content of ion impurities needs to be strictly controlled, with a focus on limiting ions such as calcium, magnesium, and chlorine that are prone to causing malfunctions. Calcium and magnesium ions are the main causes of scaling in electrolytic cells. The total hardness of the inlet water (calculated as CaCO3) should be ≤ 1mg/L. When it exceeds the standard, calcium carbonate and magnesium hydroxide precipitates will form on the electrode surface, hindering the electrolysis reaction and causing a decrease in gas production flow rate. Chloride ions have strong corrosiveness and can corrode electrode coatings and electrolytic membranes. The chlorine content in the inlet water should be ≤ 0.1mg/L, especially in PEM electrolytic cells. Excessive chloride ions may lead to membrane material degradation and pose a safety risk of hydrogen and oxygen crossover. In addition, heavy metal ions such as iron and copper should be ≤ 0.01mg/L to avoid their deposition on the electrode surface and the formation of microbatteries, which can accelerate electrode corrosion.

Although organic matter and microbial pollution are easily overlooked, they have a profound impact on equipment operation and require the establishment of targeted prevention and control standards. The chemical oxygen demand (COD) of the influent should be ≤ 1mg/L. Organic matter may be oxidized and decomposed into small molecule acidic substances during the electrolysis process, reducing the pH value of the electrolyte and affecting electrolysis efficiency; At the same time, organic matter adhering to the surface of the electrolytic membrane can block the membrane pores, leading to a decrease in proton conduction efficiency. Microbial contamination is prone to breed in water storage tanks and pipelines, forming biofilms. The detached biological flocs may block the flow channels of the electrolytic cell. The total number of bacteria in the influent should be ≤ 10CFU/mL. It is recommended to use ultraviolet disinfection or ozone disinfection to control the microbial content.

The matching of physical indicators with pre-treatment processes is an important link in ensuring that water quality meets standards. The turbidity of the incoming water should be ≤ 0.1NTU to ensure that there are no suspended particles in the water and to avoid particle wear on the electrolytic membrane or blockage of the precision flow channel; The water temperature should be controlled between 5-35 ℃. If the water temperature is too low, it will reduce the electrolysis reaction rate, while if it is too high, it may accelerate the aging of the membrane material. To meet the above requirements, the incoming water needs to go through a "pretreatment+deep purification" process: first, suspended particles are removed through quartz sand filtration, then organic matter and residual chlorine are adsorbed by activated carbon, and finally, deep purification is achieved through a combination of reverse osmosis (RO) and ion exchange resin process to ensure that the water quality fully meets the standards.

Water quality monitoring and regular maintenance are closed-loop guarantees for water quality control. It is recommended to install online conductivity and resistivity detectors at the inlet to monitor water quality indicators in real time. When the values exceed the threshold, an automatic alarm will be triggered and the inlet will be cut off; Regularly check the ion impurity content every week, and backwash and replace consumables for the pre-treatment system every month. For equipment that has been out of use for a long time, it is necessary to blow the pipeline with high-purity nitrogen and inject fresh purified water to prevent residual impurities from depositing inside the equipment.

The inlet water quality requirements for electrolytic water hydrogen generators are essentially a precise match between equipment characteristics and water quality requirements. From strict standards for purity and ion content to comprehensive prevention and control of organic matter and microorganisms, every requirement revolves around the core goal of "improving efficiency, ensuring safety, and extending lifespan". By using purified water that meets standards and establishing a comprehensive water quality monitoring system, the performance advantages of the generator can be fully utilized, and the risk of failure and operation costs can be reduced, providing stable and reliable water quality assurance for hydrogen supply in various fields.