1. Guarantee of compressed air
Oxygen comes from the air. Without the right amount of air, no oxygen is needed to separate it. The right amount of air also needs proper pressure to meet the requirements of pressure swing adsorption oxygen and nitrogen separation technology. At present, the compressed air of the PSA oxygen generator is obtained through an air compressor. The output gas of the air compressor is the input gas of the molecular sieve tower. Here, the output air pressure and gas volume of the air compressor must be properly matched with the molecular sieve adsorption tower and the whole system of the pressure swing adsorption oxygen generator. If the gas volume is too large or too small, the required High quality and high concentration of oxygen. Therefore, the stable working output of the air compressor is the basic guarantee for oxygen in the pressure swing adsorption oxygen generation mechanism, and its service life is directly related to the normal operating life of the air compressor. If the output air volume and pressure of the air compressor are declining after working for a certain period of time, it should be replaced, otherwise the oxygen production effect will be reduced, resulting in a decrease in the separation capability of the molecular sieve oxygen and nitrogen until the output air and the life of the PSA oxygen generator is over.
2. Reliable switching of molecular sieves in two towers
As the PSA oxygen generator uses two towers of molecular sieve alternate working technology, then the two towers conversion work status is also one of the key factors. If the two molecular sieve columns cannot be accurately switched in accordance with a certain pressure or time period, the oxygen production performance of the molecular sieve inside the tower will be reduced until the oxygen production capacity is completely lost. If the conversion time is too long or the pressure is too high, the following phenomenon will occur: When the molecular sieve enters the tower where adsorption and oxygen production work, the molecular sieve will become saturated and the separation capacity will decrease until the state of oxygen and nitrogen separation cannot be achieved at all. The oxygen concentration produced by the machine will be reduced until it is completely out of the air; and the tower molecular sieves that enter the nitrogen-removal purge working state will not be backwashed with high concentration of oxygen after the nitrogen is exhausted, nor will they be able to obtain good results. Analytic regeneration. In this way, the oxygen-nitrogen separation capacity of the molecular sieves in both towers will decrease until they completely fail. Similarly, if the conversion time is too short or the pressure is too low, the following state will occur: The molecular sieve inside the column that has entered the working state of adsorption and oxygen production will not obtain enough air and pressure to carry out oxygen and nitrogen separation, and the obtained product gas will not be enough. The amount will not rise, and enter the tower nitrogen molecular sieve backwash clean working state, because the time is too short, nitrogen is not complete, can not get enough backflushing oxygen, the analysis and regeneration will not be complete, the same Molecular sieve oxygen and nitrogen separation ability. Therefore, the time or pressure required to switch between the two towers must be consistent and accurate.
At present, the two towers of molecular sieve towers of the PSA oxygen generator are controlled by the pneumatic switching valve. The pneumatic switching valve is controlled by the electronic electromagnetic control or motor. Each of these links is related to the success or failure of the two towers conversion work. As long as the action of any one of these steps fails, the control conversion of the two tower molecular sieve towers will be deviated, resulting in a decrease in the oxygen-nitrogen separation capacity of the molecular sieves in the two towers until complete failure. I have observed various types of pressure swing adsorption oxygen generators. It is not uncommon for a pneumatic valve and electronic or motor control to fail after a period of use. This is also one of the main reasons for reducing the oxygen and nitrogen separation capacity of the molecular sieve in the adsorption tower and shortening the service life of the pressure swing adsorption oxygen generator.
3, the molecular sieve regeneration should be fully
The working flow of one molecular sieve of two tower molecular sieves is: the molecular sieve adsorbs nitrogen gas (saturates gradually) while the oxygen generation → molecular sieve exhausts nitrogen gas, high-concentration oxygen cleans the blowback, decomposes and regenerates → repeats the previous process. The two molecular sieve columns alternate, and the molecular sieves in the tower are continuously subjected to oxygen-nitrogen separation. Therefore, the molecular sieve must be analyzed and regenerated. The more thorough the analysis, the greater its ability to regenerate and the longer its service life. In the oxygen production process of the two tower molecular sieves, a part of the high-concentration product oxygen produced by one tower is to be separated out for use in the analysis of the molecular sieve cleaning blowback after the nitrogen is exhausted in the other tower. After the nitrogen is removed, the high concentration of oxygen in the purge blowback is higher, and the analytical effect of the molecular sieve will be better. When entering the next cycle, the ability to adsorb nitrogen will be stronger and the oxygen production effect will be better. Conversely, if the amount of high-concentration oxygen is reduced during cleaning and backflushing, then the analytical effect of the molecular sieve will be poor, and the oxygen-nitrogen separation capacity will be worse when it enters the next cycle, and the effect of oxygen production will be reduced.
The PSA oxygen generator is designed with a rated oxygen output. Within the rated oxygen output, the high concentration of oxygen separated from the purge and blowback is generally sufficient to meet the need for cleaning and backflushing after nitrogen is exhausted. However, if the user is used improperly, exceeding the rated oxygen output will cause great damage to the molecular sieve. First of all, exceeding the rated output will inevitably be supplemented with a part of nitrogen, so that the output oxygen concentration cannot reach more than 90%, and the oxygen quality will decline. Secondly, the oxygen quality of the finished product will decrease, which will reduce the oxygen concentration used for cleaning the blowback. The resolution and regeneration effect of the molecular sieve in the tower is reduced, which directly affects the oxygen production capability and service life of the molecular sieve. If the user can use about two-thirds of the oxygen content of the PSA oxygen generator, the molecular sieve can be better protected, which is beneficial to extending the service life of the molecular sieve.