CMS carbon molecular sieve nitrogen generator is the mainstream pressure swing adsorption (PSA) nitrogen production equipment in the industrial field, which relies on the selective adsorption characteristics of carbon molecular sieve to realize efficient separation of nitrogen and oxygen in air. Nitrogen purity is the core performance index of CMS nitrogen generator, and purity insufficiency is one of the most common faults in the operation of the equipment, which directly affects the normal use of industrial nitrogen and production quality. The insufficient purity of the system is mainly caused by molecular sieve failure, air source pollution, system parameter abnormality and equipment pipeline failure, and targeted fault analysis and maintenance can effectively solve the purity problem and restore the equipment’s working performance.
The failure and aging of carbon molecular sieve are the primary causes of insufficient nitrogen purity. Carbon molecular sieve is the core adsorption medium of CMS nitrogen generator. After long-term cyclic adsorption and desorption operation, the molecular sieve will be powdered, blocked and aged, resulting in reduced oxygen adsorption capacity and decreased separation efficiency. In addition, if the raw compressed air contains excessive oil and water impurities, the oil molecules will adhere to the surface of the molecular sieve and block the microporous structure, causing permanent deactivation of the molecular sieve and serious nitrogen purity decline. For this fault, users need to regularly detect the nitrogen purity and molecular sieve activity. For slightly aged molecular sieves, nitrogen purging and regeneration treatment can be carried out; for severely failed and invalid molecular sieves, they need to be replaced in time to restore the equipment’s nitrogen separation capacity.
Air source pollution and post-processing system failure are important inducements for purity insufficiency. The front-end air compression and purification system of CMS nitrogen generator is responsible for providing dry, oil-free and dust-free compressed air. If the cold dryer fails to reduce temperature and remove water, or the precision filter element is blocked and invalid, the raw air will contain a large amount of water, oil and dust impurities, which will not only affect the molecular sieve activity, but also cause incomplete gas separation and low nitrogen purity. At the same time, the failure of the pressure stabilization system and the unstable working pressure of the equipment will affect the adsorption and desorption cycle of the molecular sieve, resulting in insufficient oxygen removal and unqualified nitrogen purity. The solution is to regularly inspect and maintain the air purification system, replace filter elements on schedule, check the operating state of the cold dryer, and calibrate the system pressure parameters to ensure stable and qualified raw air supply.
Pipeline leakage and parameter setting errors will also lead to persistent insufficient nitrogen purity of the system. Long-term operation of the equipment may cause aging and loosening of connecting pipelines, valve wear and air leakage, resulting in the mixing of external air with high oxygen content into the separated high-purity nitrogen, reducing the overall gas purity. In addition, unreasonable setting of adsorption time and cycle parameters will lead to incomplete oxygen adsorption and insufficient nitrogen purification. For such faults, it is necessary to conduct a comprehensive inspection of the equipment’s gas pipeline and control valves, replace aging sealing parts and repair leakage points, and re-calibrate the adsorption cycle parameters according to the equipment model and gas production demand. Regular daily maintenance, parameter calibration and fault detection can effectively avoid the recurrence of nitrogen purity insufficiency faults and ensure the long-term stable and high-purity operation of the CMS carbon molecular sieve nitrogen generator system.
