Air separation -- simply speaking, it is a set of industrial equipment used to separate each component of gas in the air and produce oxygen, nitrogen and argon. There are also rare gases such as helium, neon, argon, kr.com, xenon, radon, etc.
I. Air separation can be divided:
1. Air filtration system; dust removal and filtration to remove dust and mechanical impurities.
2. Air compressor system; work on gas, improve energy and have refrigeration capacity.
3. Air precooling system; air precooling can reduce energy consumption and improve economy. Compared with the one-time throttling cycle without precooling, the one-time throttling cycle with precooling increases the refrigeration cycle, reduces the work burden of the heat exchanger, and makes full use of the cooling capacity of the product.
4. Air purification system; explosion-proof and purification; air is composed of multiple components. Besides oxygen, nitrogen and other gas components, there are also water vapor, carbon dioxide, acetylene and a small amount of dust and other return impurities. With the air entering into the air compressor and the air separation device, these impurities will cause great harm. Solid impurities will wear the running parts of the air compressor, block the cooler and reduce the cooling effect; water vapor and carbon dioxide will freeze and elude in the process of air cooling, which will block the equipment and gas pipeline, making the air separation unit unable to produce; after acetylene enters the air separation unit, it will lead to the occurrence of explosion accident, therefore, in order to ensure the safe operation of the oxygen generator, it is very necessary to remove these impurities. The difference of the adsorption capacity of multi-component in the gas mixture by using solid adsorbents; the ratio of oxygen and nitrogen production is 1: (2.5 ~ 3.5); function: absorb water, carbon dioxide, acetylene, propylene, propylene, heavy hydrocarbon, N in the air2O and other impurities.
5. Air compression expansion system; refrigeration system, heat exchange system, in the process of expansion, there is external power output, after expansion, the gas internal energy increases, need to consume energy, these energy needs to be compensated by kinetic energy, therefore, the gas temperature is bound to decrease. Heat exchange system: realize energy transmission, improve economy and low temperature operation conditions.
6. Air separation system; nitrogen/oxygen separation the main distillation column system consists of air separation, which can put an appropriate amount of inflated air (accounting for 20% of the Air ~ 25%) directly send it to the top tower for rectification; extract nitrogen from the top of the lower tower or from the top cover of the condensing evaporator, re-heat and enter into the nitrogen turbine Expander. After passing through the expander and receiving the cooling amount, output or empty as a product.
7. Oxygen compression;
8. Nitrogen compression;
9. Liquid storage vaporization system;
II. Process Description
Brief description of the flow path: After removing dust and mechanical impurities from the air suction filter, the raw material air enters the air turbine compressor and conducts Intermediate cooling with the help of the intermediate cooler, compress the air to about 0.62MPa (A), and then enter the air cooling tower for cooling.
Air exchanges heat and mass with water in the direct contact air cooling tower to cool down ~ 10℃, then enter the molecular sieve adsorber used alternately. The water used for cooling air has two parts: one part is normal temperature water, which enters the middle of the air cooling tower after being pressurized by the pump; the other part is called chilled water, which is cooled by ordinary cooling water through the water nitrogen tower, then it enters the top of the air cooling tower through the pressure of the chilled water pump.
The air of the cooling tower enters into the molecular sieve adsorber. The molecular sieve adsorber is a vertical double-bed layer, which is used to remove water, carbon dioxide and some hydrocarbon in the air, thus obtaining clean and dry air. Two adsorbers are used alternately, that is, one adsorber adsorbs impurities, and the other is regenerated by polluted nitrogen.
