Vacuum pressure swing adsorption oxygen generation system and control method thereof

Abstract

The invention discloses a vacuum pressure swing adsorption oxygen generation system and a control method thereof. The pressure swing adsorption oxygen generation system is provided with two independent pressure equalizing tanks; the forward pressure release is performed in two times, wherein the oxygen rich air in a first adsorber is fed into a first pressure equalizing tank in the first-time forward pressure release, the oxygen rich air is fed into a second pressure equalizing tank in the second-time forward pressure release; the gas discharged by the first-time forward pressure release is used as the gas of a first charging step of a second adsorber, and the gas discharged by the forward pressure release of the second time is used as the gas of a cleaning step of the first adsorber. Thus, the product gas is not used in the cleaning step, the loss of the product gas is reduced; in addition, the adsorber is charged by only the gas discharged from the first-time forward pressure release, the total oxygen concentration in the adsorber can be improved, so as to facilitate the adsorbing operation. Therefore, the system and the control method has the advantages that the loss of the product oxygen is reduced and the concentration distribution of the oxygen in the adsorber is improved, and thus the yield of the product oxygen is increased, the efficiency of the adsorbing operation is improved, the energy consumption is reduced and the cost is saved.

Description

technical field [0001] The invention relates to pressure swing adsorption air separation oxygen production technology, in particular to a vacuum pressure swing adsorption oxygen production system and a control method thereof. Background technique [0002] Vacuum pressure swing adsorption VPSA oxygen production system, that is, under the condition of higher than the atmospheric pressure, the special molecular sieve and adsorbent for VPSA oxygen production are used to selectively adsorb nitrogen, carbon dioxide, water and other impurities in the air, and the molecular sieve and The adsorbent is desorbed to circulate and produce oxygen with high purity (70~95%). [0003] The VPSA oxygen generation system in the prior art consists of a blower, a vacuum pump, a switching valve, two adsorbers and a buffer tank. The raw material air after the dust particles are removed by the suction inlet filter enters the blower, and is transported by the blower into one of the adsorbers. The b...

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Problems solved by technology

[0007] 2. During the desorption process, when the desorption pressure is close to the predetermined minimum pressure, the adsorber needs to be cleaned. In the existing VPSA oxygen production process, the cleaning step uses a part of the product gas in another adsorber, which will cause loss of product gas;

[0008] 3. The best distribution of oxygen concentration inside the adsorber is as follows: the oxygen concentration of the adsorber should gradually increase from the bottom to the top. If the oxygen concentration at the top of the adsorber is lower than the bottom, it is not conducive to the adsorption operation and will reduce the adsorption capacity of the adsorbent. Utilization efficiency reduces the oxygen recovery rate. In addition, most of the product gas used in the cleaning process will be sucked away by the vacuum pump, that is, this part of the product body is wasted.

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