Advantages of structured packing for high temperature solenoid valve

1. The separation efficiency of structured packing is high, and the extraction rate of rectification tower is high. The extraction rate of oxygen and nitrogen of air separation equipment is divided into two types: extraction rate of complete set of equipment and extraction rate of rectification tower. Due to the extraction rate of complete set of equipment and the capacity of air separation equipment . The output of liquid products is related to other factors. It is difficult to measure the high separation efficiency of structured packing. The extraction rate of the rectification tower, especially the extraction rate of argon, can better represent the design level of the air separation equipment. After actual measurement, it has been put into production. New air separation equipment. The oxygen extraction rate of its rectification tower has reached over 99%; the argon extraction rate has reached 79%.

The operating value of the oxygen content in the sewage nitrogen of the upper tower is the main indicator of the extraction rate of rectification. According to actual measurement, the oxygen content of the sewage nitrogen can be less than 0.1%, and can even reach 150-200x10-4%.

The structured packing upper column and the crude argon column have high separation efficiency, which is the result of the significant reduction in their operating pressure. The lower the operating pressure, the separation of oxygen, nitrogen and argon is greatly beneficial, especially oxygen and argon. Separation. In general, the extraction rate of oxygen can be increased by 1% to 3%; the extraction rate of argon can be increased by 5% to 10%.

The extraction rate of the rectification tower also depends to a large extent on the amount of expanded air entering the upper tower, especially on the extraction rate of argon. Therefore, the isentropic efficiency of the turboexpander and the pressure increase of the booster are continuously improved. Ratio is the key to improve the extraction rate of the distillation tower.

2. The structured packing has large gaps, large production capacity, and reduced tower diameter for easy transportation

The porosity of structured packing can reach more than 95%. In the sieve-plate tower, the orifice area accounts for about 80% of the cross-section of the tower, and the opening ratio is about 8-12%, which are far less than the air drop rate of the packing layer. For the same load, the ratio of the tower diameter of the packed tower The sieve plate tower is small; under normal circumstances, its cross-sectional area is only ~70% of the sieve plate tower. For large air separation plants, the reduced diameter of the tower is conducive to transportation.

3. The structured packing has less liquid holding capacity, greater operating liquid-to-air ratio and flexibility, and rapid change of working conditions

The operating load of the sieve tray is limited by the leakage of the sieve and the flooding speed, and the packed tower is only limited by the flooding speed, so their operating load can be changed in a relatively large range, and the design load range of the packed tower can reach 40% ~120%, the oxygen output of the upper column of the structured packing of the 12000m3/h air separation plant in Shanghai Steel No. 5 Plant can be adjusted within the range of 9000-14000mm3/h, and the operating load range is only 75%-117%.

Because the liquid holding capacity of the packed tower is small, generally only 1% to 6% of the tower volume, while the liquid holding capacity of the sieve plate tower is 8% to N% of the tower volume. The small liquid holding capacity means that the liquid is in the tower. The residence time is short and the operating pressure drop is small, which is also conducive to variable-condition operation, but it must be verified in the actual operation of variable-condition in the future.

4. The device startup time is greatly shortened

The start-up process of the air separation plant is running without product output, so shortening the start-up time is one of the ways to save energy and reduce consumption of the air separation plant. The start-up time of the air separation plant refers to the time required to start the expander until the oxygen is released. After the packing is adjusted, the amount of liquid held during normal rectification is greatly reduced, which greatly reduces the start-up time of the air separation plant.