High purity nitrogen air separation FAQ

For the maintenance of nitrogen-water precooling system, the most important thing to pay attention to is to prevent the occurrence of nitrogen suffocating accident. There have been several lessons that maintenance workers died of nitrogen suffocating in China. During the overhaul, nitrogen is often used to warm the unit at the same time, and the heated nitrogen often flows into the cooling tower through the three-way valve of dirt and nitrogen, causing the nitrogen concentration in the tower to be too high. Therefore, before heating the device, the air cooling tower and water cooling tower should be separated from the device by blind plate; the oxygen content in the air cooling tower and water cooling tower should be analyzed. When the oxygen content is 19% ~ Only between 21% can the maintenance personnel be allowed to enter; if they work in the area where the oxygen content is less than 19%, there must be someone to supervise and wear isolation masks (oxygen respirator, long tube m...

What should be paid attention to during the switching operation of molecular sieve adsorbers in air separation equipment

What issues should be paid attention to when operating the molecular sieve purification system of the air separation equipment

When air enters into the cooler (or switching heat exchanger) through the last stage cooler of air compressor and nitrogen water precooler, the content of water vapor in the air has reached the saturated state. After that, with the decrease of temperature, the corresponding pressure of saturated water vapor is decreasing; the content of saturated water per cubic meter of air is gradually decreasing. For example, when the temperature drops from 30℃ to-60℃, the saturated moisture content in the air decreases from 30.3g/m3 to 0.011g/m3. The extra water is precipitated on the stuffing of the cooler or the fin of the Plate-fin Heat Exchanger. At-60℃, the saturated water vapor pressure has decreased to 1.067 Pa, which can be considered as no water, so 30℃ to-60℃ is called the water precipitation area. The "three-phase point" of water (the state of the coexistence of gas phase, liquid phase and solid phase) pressure is 0.613kPa, and the temperature is 0.01 ℃. When the partial pressure of t...

Why does the acetylene content not exceed the standard, and the main cooling system of the air separation equipment may also explode

The carbon molecular sieve of Nitrogen generator has high requirements on the quality of compressed air, while the compressed air contains a large amount of water, certain dust and oil mist, therefore, before the compressed air enters the nitrogen generator, it must be treated with cooling, water removal, oil removal and so on. The purification treatment of compressed air is of vital importance, which should not be ignored! Because the quality of compressed air purification treatment is directly related to the service life of carbon molecules, thus directly related to the long-term effective use of nitrogen generator. I. Start-up steps of the nitrogen generator 1) turn on the power supply of the cold dryer and precool for five minutes. 2) open the air valve that enters the air dryer, and let the compressed air enter the air dryer to remove water, oil and dust. 3) open the air valve entering the nitrogen generation machine, and let the dry clean air enter the nitrogen generation mach...

Air compressor absorbs the external air and compresses the gas generated through the air dryer and drier. After separating the water in the air, the gas flowing into the nitrogen generator generally contains only nitrogen molecules and oxygen molecules. When the gas enters into the two absorption towers of the main engine of the nitrogen generator, the high-performance carbon molecular sieve with oxygen absorption specially configured in the tower will be automatically switched by the valve under pressure according to the different "selective absorption" of nitrogen and oxygen in the air, realize the pressure adsorption process of the two towers and the pressure diffusion process, that is, carbon molecular sieve adsorbs oxygen under pressure, while nitrogen passes through, is collected and transported. When the adsorption is saturated, it will automatically switch to another absorption tower for pressure adsorption, and the main engine of the chilled nitrogen generator will release ...

Why is there water analysis after the air is compressed and cooled by the air separation equipment

Carbon molecular sieve (CMS) is a new type of non-polar adsorbents, which has the performance of absorbing oxygen molecules in the air under normal temperature and pressure, thus obtaining nitrogen-rich bodies. The most remarkable feature of adopting the new nitrogen production technology of carbon molecular sieve pressure changing absorption method is: the impurity content of N2 product is low, the concentration of N2 and the gas volume can be adjusted arbitrarily according to the need, and high purity N2 with O2 content less than 5PPm and dew point less than-60℃ can be obtained through refining. In 1960s, carbon molecular sieve was firstly manufactured successfully in America and was promoted and applied soon. At first, carbon molecular sieve was used as the absorbant to separate oxygen from the air, and later it was gradually applied to the equipment for producing nitrogen. By the end of 1970s S and the beginning of 1980s S, the demand for nitrogen in various countries around the...

The liquid nitrogen supercooler uses the low temperature gas nitrogen from the upper tower to cool the liquid nitrogen from the lower tower, so as to reduce the gas rate when the liquid nitrogen throttling enters the upper tower. Why is the temperature of gas nitrogen lower than that of liquid nitrogen? This is because for the same substance, phase change temperature (saturation temperature) is related to pressure. The lower the pressure is, the lower the corresponding saturation temperature is (see Figure 8 ). On the top of the tower, it is in the saturated state of the coexistence of gas nitrogen and liquid nitrogen, both of which have the same saturation temperature. The absolute pressure of nitrogen going out of the tower is about 0.13MPa, and the corresponding saturation temperature is-193℃, which is also the temperature of the nitrogen saturated vapour going out of the tower. The absolute pressure on the top of the lower tower is about 0.55MPa, and the corresponding nitrogen s...

As for the oxygen generator in the flow of switching heat exchanger, in order to achieve the self-elimination of moisture and carbon dioxide, the amount of dirt and nitrogen is relatively large, so the condition of not freezing can be guaranteed. Therefore, the amount of pure gas and nitrogen products is relatively small, it can only reach 1.3 times of the output of gas and oxygen at most, so the amount of pure liquid nitrogen provided by the lower tower is less, so a stream of sewage nitrogen can be extracted to the upper tower, which increases the reflux ratio of the distillation section of the upper tower, it has greater rectification potential, thus allowing more inflated air to enter the upper tower to prevent inflated air from passing by and affecting oxygen extraction rate. As for the oxygen generator in the process of purification, pressurization and expansion of molecular sieve, the quantity of pure gas and nitrogen products has been greatly increased due to the lack of sel...

The advantage of using this process design is that the nitrogen cycle compressor and the medium/high/ultra-high pressure product nitrogen press are combined into one machine, eliminating the need to use multiple product nitrogen presses. Due to the high nitrogen to oxygen ratio, a portion of the nitrogen must be extracted from the top of the low pressure tower to make up the nitrogen cycle compressor. This make-up compressor is also combined with the low-pressure/low-pressure product nitrogen pr...