According to the principle of pressure swing adsorption, the industrial nitrogen generator uses high-quality carbon molecular sieve as adsorbent to produce nitrogen from air under certain pressure. After purification and drying of compressed air, pressure adsorption and decompression desorption were carried out in the adsorber. Nitrogen is preferentially adsorbed by oxygen in the carbon gas phase due to the diffusion rate of nitrogen in the molecular sieve. After that, the adsorbent desorbs oxygen and other impurities to realize regeneration. Generally, two adsorption towers are set up in the system, one for nitrogen production and the other for desorption and regeneration. The opening and closing of pneumatic valves are controlled by PLC program controller to make the two towers circulate alternately, so as to realize the purpose of continuous production of high-quality nitrogen. The whole system consists of the following components: compressed air purification components, air storage tank, oxygen and nitrogen separation device, nitrogen buffer tank.
1. The compressed air provided by the air compressor is first passed into the compressed air purification unit. Most of the oil, water and dust are removed from the compressed air by the pipeline filter, and then the water, oil and dust of the fine filter are further removed by the freeze dryer, and the deep purification is carried out by the super fine filter immediately following. According to the working conditions of the system, a set of compressed air degreaser is specially designed to prevent possible oil penetration and provide sufficient protection for carbon molecular sieve. The rigorous design of air purification components ensures the service life of carbon molecular sieve. The clean air treated by the module can be used for instrument air.
2. The function of the air storage tank is to reduce the air flow pulsation and act as a buffer, so as to reduce the system pressure fluctuation and make the compressed air pass through the compressed air purification unit smoothly, so as to fully remove the oil and water impurities and reduce the load of the subsequent PSA oxygen and nitrogen separation device. At the same time, when the adsorption tower is switching, it also provides a large amount of compressed air for PSA oxygen and nitrogen separation device to boost pressure rapidly in a short time, which makes the pressure in the adsorption tower rise to the working pressure quickly and ensure the reliable and stable operation of the equipment.
3. There are a and B in the adsorption tower equipped with special carbon molecular sieve. When the clean compressed air enters into the inlet end of tower a and flows through the carbon molecular sieve to the outlet end, O2, CO2 and H2O are absorbed by it, and the product nitrogen flows out from the outlet of the adsorption tower. After a period of time, the adsorption of carbon molecular sieve in tower a is saturated. At this time, tower a automatically stops adsorption, compressed air flows into Tower B for oxygen absorption and nitrogen production, and molecular sieves of tower a are regenerated. The regeneration of molecular sieve is realized by rapidly lowering the adsorption tower to atmospheric pressure to remove adsorbed O2, CO2 and H2O. The adsorption and regeneration of the two towers are carried out alternately to complete the separation of oxygen and nitrogen, and the nitrogen is continuously output. All the above processes are controlled by PLC. When the purity of nitrogen at the outlet is set, the PLC program will open the automatic vent valve to vent the unqualified nitrogen automatically to ensure that the unqualified nitrogen does not flow to the gas consumption point. Noise reduction is used to make the noise less than 75dBA when the gas is vented.
4. Nitrogen buffer tank the nitrogen buffer tank is used to balance the pressure and purity of nitrogen separated from the nitrogen oxygen separation system to ensure the stability of continuous nitrogen supply. At the same time, after the working switch of the adsorption tower, it will recharge part of its own gas to the adsorption tower, on the one hand, it helps the adsorption tower to boost pressure, on the other hand, it also plays a role in protecting the bed, which plays a very important auxiliary role in the process of equipment operation.
On 2018-08-08 11:45:46
