SS 304 Gas Liquid 125Y Structured Packing In Distillation Column

SS 304 Wire Gauze Structured Tower Packing For Distribution Of Gas Liquid 125Y

Metal Structured Packing  Introduction

Structured packing include knitted structured packing,wire gauge structured packing,metal perforated plate corrugated packing.

Knitted structured packing is made from multiple strands of fine wire that are knitted together in a tubular pattern and then crimped and coiled or layered to provide a three dimensional structure of peak and valleys. The multi-strand fine wire provides a high surface area. This structured packing is suited for applications that demand high separation efficiency with a lower pressure drop, such as, high purity product distillations and solvent and byproduct recovery.

Wire gauge structured packing is manufactured from specially woven wire gauze that is pressed into smooth plates, uniformly perforated, corrugated and stacked with corrugations in alternate directions. This construction promotes intimate gas/liquid contact. The woven structured packing with of high separation efficiency, is used in pharmaceuticals and fine chemicals.

Metal perforated plate corrugated packing is made from perforated plate with channel corrugation on surface. It is formed from vertical sheets of corrugated metal with the angle of the corrugation reversed in adjacent sheets to form an open structure with inclined flow channel. The packing has advantages such as high capacity, low resistance, high mass-transfer efficiency and strong resistance to fouling. It is widely used in unit operations like rectification, absorption and extraction.

1. The pressure drop of the structured packing is significant

Since the gas-liquid two-phase membrane contact in the structured packing is different from the bubbling contact of the two phases in the sieve tray, the pressure drop of the packed tower is only 1/4 to 1/6 of the sieve tray. For example, the operating resistance of the tower on the structured packing is 3.5-4.2 kPa, the operating pressure at the bottom is only 35-45 kPa, the lower tower is still still using the sieve tray tower, and the operating resistance is not changed, so the operating pressure of the lower tower is correspondingly reduced by 0.05~ 0.06 MPa, generally 0.44 to 0.48 MPa, so that the shaft power of the air compressor can be reduced by 5% to 7%.

2. High efficiency of structured packing separation

The lower the operating pressure of the upper column, the greater the separation of oxygen, nitrogen and argon, especially the separation of oxygen and argon. Generally, the extraction rate of oxygen can be increased by 1% to 3%, and the extraction rate of argon can be increased by 5%. 10%, practice has proved that the oxygen extraction rate of air separation equipment has reached more than 99%, and the extraction rate of argon has reached more than 80%.

The extraction rate of the distillation column depends to a large extent on the amount of expansion air entering the upper column, especially for the extraction rate of argon, so the isentropic efficiency of the turboexpander and the supercharging of the supercharger are continuously improved. The ratio is the key to increasing the extraction rate of the distillation column.

3. The regular packing has a small liquid holding capacity

The volume of the structured packed column is generally only 1% to 6% of the column volume, while the holding capacity of the sieve column is 8% to 10% of the column volume. The small liquid holding capacity means that the liquid stays in the tower for a short time and the operating pressure drop is small, which is beneficial to the operation of the variable working condition. The structured packing tower can be designed in the range of 40% to 120%. The oxygen production of the upper tower of the 12000m3/h air separation plant of Shanggang No. 5 Plant can be adjusted within the range of 9000~14000mm3/h, and the operating load range is only 75%~117%.

4. Regular packing gap is large

The structured packing has a void ratio of more than 95%. In the sieve tray tower, the orifice plate area accounts for 80% of the tower section, and the opening ratio is 8% to 12%, which are far less than the void ratio of the filler layer. For the same load, the tower of the packed tower is smaller than the sieve tower; in general, the cross-sectional area is only about 70% of the sieve tower, which is advantageous for large-scale air separation equipment.

5. The device startup time is greatly shortened

The starting process of the air separation equipment is no product output operation, so shortening the starting time is one of the ways to save energy and reduce consumption of the air separation equipment. The starting time of the air separation equipment refers to the time required to start the expansion machine to the oxygen output. After the completion of the packing, the amount of liquid held during normal rectification is greatly reduced, and the start-up time of the air separation plant is greatly shortened. After the conventional packing is used in the upper tower, the amount of liquid held during normal rectification is greatly increased. After the descent, the start-up time of the air separation plant is greatly shortened, and the general start-up time only takes 26 to 30 hours.

6. The oxygen content in the argon fraction is about 90%.

To reduce directly to 1~2×10-4% by cryogenic rectification, the theoretical plate number of the rectification column needs about 180 pieces, the sieve plate plate needs about 300 pieces, and the resistance is up to about 100 kPa. Obviously, the crude argon is It is impossible to discharge the outside of the tower, and the height of the structured packing is about 45m. The resistance is only 14 to 16 kPa, so the realization of the full rectification argon process is possible.

Metal Structured Packing Application

• Fine chemicals.
• Solvent recovery.
• Chemical product refining.
• Atmospheric rectification.
• Vacuum rectification.