Common Fault Analysis of Liquid Nitrogen Machines and Carbon Molecular Sieves in Laboratories

　　Laboratory Liquid Nitrogen GeneratorThe main phenomena of carbon molecular sieve leakage are black smoke in the oxygen-enriched exhaust of the nitrogen generator, molecular sieve particles spraying out, molecular sieve pulverization, and damage to internal components of the equipment. These are the direct causes of powder leakage in the nitrogen generator. Let's take a look at the common fault analysis of carbon molecular sieves in laboratory liquid nitrogen generators!

　　1. Poor Molecular Sieve Quality

　　Molecular sieves are adsorbents that adsorb nitrogen and oxygen. Their quality directly affects the performance and gas purity of the nitrogen generator. High-quality molecular sieves have better dust resistance, moisture resistance, strength, and adsorption capacity than ordinary molecular sieves. Poor-quality molecular sieves have a short lifespan and will pulverize during operation.

　　2. Insufficient Molecular Sieve Filling

　　Laboratory liquid nitrogen generators do not have dedicated vibration equipment for filling molecular sieves, resulting in low filling density of the molecular sieves inside the machine. During the operation of the nitrogen generator, the compressed air flows upward from the bottom of the tank, and after the oxygen is adsorbed by the molecular sieve, the nitrogen is transported to the downstream pipeline. Frequent collisions of the airflow continuously wear down the internal molecular sieves, and the position of the molecular sieves gradually decreases. After dropping to the lower limit of the top cylinder, the cylinder no longer compresses and restricts the molecular sieves, accelerating the pulverization of the molecular sieves. The powder passes through the filter and leaves with the oxygen-enriched exhaust.

　　3. Gas Source Pressure

　　The purified compressed air enters the bottom of the nitrogen generator tower, and the gas source pressure affects the operating condition of the nitrogen generator. Because the PSA nitrogen equipment has a high pressure reduction frequency, the pressurized gas impact on the molecular sieve is significant. The pressure and flow rate of all gas sources must be strictly controlled to prevent wear on the carbon molecular sieve. If the air source pressure is too high, the impact force of the air source on the molecular sieve increases when the air valve opens, and the friction between the molecular sieves increases. When the air valve closes after the molecular sieve has completed adsorption, the static friction when the molecular sieve falls also increases relatively. If the gas source pressure is too low, the time for the molecular sieve to adsorb oxygen to saturation will be prolonged. In other words, the operating time for the nitrogen generator to produce qualified nitrogen is longer, the friction time between the molecular sieves is longer, and the pulverization of the molecular sieves is accelerated.

　　4. Non-Strict Air Valves

　　Laboratory Liquid Nitrogen GeneratorAir-quick butterfly valve groups are installed on the piping, and pressure equalization is performed on the valve group, exhaust valve group, and vent valve group. If any valve group is not closed properly and air leaks, another nitrogen generator that is temporarily not working may generate airflow. Even with the rush of airflow, the static friction between the molecular sieves will increase, and the pulverization of the molecular sieves will intensify.

　　5. Malfunctions Caused by High Levels of Water and Oil in the Intake Air

　　The intake source of the laboratory liquid nitrogen generator is equipped with multi-stage filtration and drying facilities. This equipment mainly includes a refrigeration dryer, a high-efficiency filter, an alumina heating dryer, and a precision filter, which constitute the gas source purification system. The filter elements and alumina ceramic balls of the gas source purification system need to be replaced regularly. If the filter elements are damaged or replacement is delayed, the gas source will contain water and oil, and water and oil are important factors affecting the quality and life of the molecular sieve.

　　6. Loose Top Cylinder Pressure

　　Low instrument wind pressure, cylinder damage, and low nitrogen generator level are the reasons for insufficient top cylinder pressure. On the other hand, when the upper cylinder pressure is weak, the cylinder no longer restricts the molecular sieve. After the airflow enters, it provides the molecular sieve with greater activity space, increasing the impact force between the molecular sieves and accelerating the pulverization of the molecular sieve.7. Filter and Coconut Mat Rupture

　　Long-term impact of airflow and molecular sieves causes damage to the middle part of the filter and coconut mat, causing the molecular sieves to fall to the bottom of the tank and leak out along with the oxygen-enriched exhaust pipe. If the damaged filter and coconut mat are not replaced in time, it will form a vicious cycle, affecting the purity and flow rate of the product gas, and seriously affecting the stability and safety of the equipment operation.

　　The above is an introduction toLaboratory Liquid Nitrogen Generatorcommon fault analysis of carbon molecular sieves. If you want to learn more, please Contact Us!