Distillation tower is a chemical equipment made of rare metal titanium and its alloy materials, which has the characteristics of high strength, toughness, high temperature resistance, corrosion resistance, and light specific gravity; Therefore, it is widely used in fields such as chemical engineering, petrochemicals, metallurgy, light industry, textiles, alkali production, pharmaceuticals, pesticides, electroplating, electronics, etc.

1、 Tower height
The tower height of a plate tower consists of the main body height, top space height, bottom space height, and skirt height.
Distillation tower
Distillation tower
1. Main body height
The height of the main body of the plate tower is the vertical distance between the first tray at the top of the tower and the last tray at the bottom of the tower. The number of theoretical trays is commonly used in distillation operations to describe the height of the tower. To determine the tray efficiency, the actual number of trays can be obtained from the theoretical number of trays, and then multiplied by the tray spacing to obtain the main height of the plate tower.
2. Top space height
The height of the top space of the plate tower refers to the distance from the tangent line of the first tray at the top of the tower to the top head of the tower. In order to reduce the amount of liquid carried in the gas at the top of the tower, the top space is generally taken as 1.2-1.5m. Sometimes, in order to improve product quality, it is necessary to remove more mist and foam carried in the gas, so a removal device can be installed at the top of the tower
Foam dispenser. If a metal demister is used, the distance from the bottom of the mesh to the tray is generally not less than the spacing between the trays.
3. Bottom space height
The bottom space height of a plate tower refers to the distance from the last layer of tray at the bottom of the tower to the tangent line of the bottom head of the tower. When the feeding system has a buffer margin of 15 minutes, the residence time of the kettle liquid can be taken as 3-5 minutes, otherwise it must be taken as 15 minutes. But for towers with high liquid flow rates, the residence time is generally set at 3-5 minutes; For materials that are prone to coking, the residence time at the bottom of the tower should be shortened, generally taking 1-1.5 minutes. Based on this, the height of the bottom space can be calculated according to the flow rate of the kettle liquid and the diameter of the tower. The bottom space of the tower kettle provides space for gas-liquid separation and buffering.
4. Skirt height
The tower body is often supported by a skirt, and sometimes it is also placed on a frame and supported by ears. The skirt height refers to the height between the tangent line of the tower bottom head and the foundation ring, determined by the process conditions.
(1) The net positive suction head required by the pump is calculated based on the low liquid level of the tower kettle. The vacuum operation of a vertical thermosiphon reboiler requires a high height of the tower skirt.
(2) Installation height, length, etc. of the reboiler.
2、 Vertical thermosiphon reboiler inlet
1. Pipe mouth orientation
(1) It is best to install the inlet of the reboiler parallel to the downcomer plate of the bottom tray. If parallel installation is not possible due to tower layout and piping, consideration must be given to installing baffles.
(2) Attention should be paid to the flow of personnel at the inlet of the reboiler, which should not hinder the outflow of liquid from the bottom receiving tray.
(3) If it is superheated steam entering the tower, in order to prevent the liquid in the downcomer from being partially vaporized due to heating, the superheated steam inlet pipe should not be placed next to the downcomer.
2. Pipe mouth height
The height of the pipe opening should consider:
(1) The inlet of the thermosiphon reboiler is connected at a certain distance below the bottom layer of the tower plate. This distance should be able to provide a gas phase space for the separation of gas and liquid phases in the thermosiphon reboiler (usually with a gas phase mass fraction of 5% to 100%) and the redistribution of gas phase on the bottom tray. Based on experience, the distance between the inlet of a thermosiphon reboiler and the upper tray is usually a multi plate spacing of about 500mm, generally not exceeding 800mm.
(2) Above the upper limit of the tower kettle liquid level. The driving force of a thermosiphon reboiler is the density difference. Usually, the density difference between the inlet of the thermosiphon reboiler and the tower mouth of the thermosiphon reboiler is not very large, and the driving force is small. If the return port is in the liquid phase zone, it will increase the resistance, deteriorate the fluidity of the reboiler, and affect the heat transfer effect. In addition, it also causes the liquid level to be unstable, and the gas-liquid mixture at the outlet of the reboiler breaks through the liquid layer, sometimes generating great force and damaging the tray and internal components.
(3) Layout and piping requirements for vertical thermosiphon reboiler. When installing a vertical thermosiphon reboiler, the position of the upper tube plate of its tube bundle should be aligned with the normal liquid level of the tower kettle
The connecting pipeline from the flat and vertical thermosiphon reboiler to the tower kettle should be as short as possible, without bag shapes, and generally without valves.
3、 Level gauge port
(1) Connecting baffle above the liquid level gauge
In order to monitor and adjust the liquid level inside the kettle, a pair of liquid level gauge interfaces must be installed on the tower kettle. When the upper connecting port is directly connected to the tower wall, inaccurate readings may occur due to the influence of materials returning from the reboiler and liquid flowing down the tower wall into the liquid level meter. A baffle must be installed at the connection point above to display the liquid level
Accurate and stable.
(2) Operating liquid level
During tower operation, the liquid level of the tower kettle usually includes normal level, minimum level, and maximum level. When there is interlocking control, there are also high high liquid level and low low liquid level. The liquid level needs to be determined based on the principle of determining the height of the bottom space. The normal liquid level is generally between 50% and 60% of the highest liquid level.
(3) Length of liquid level gauge
The length of the tower kettle level gauge should cover the liquid level range of various operating conditions (normal liquid level, minimum liquid level, and maximum liquid level) during the operation process, in order to monitor and adjust the liquid level.
4、 Integrated design of tower kettle system
The nozzle of the tower kettle is sometimes designed by the manufacturer of the tower internals. When reviewing the drawings, the design unit needs to review the layout of the tower and reboiler, and pay attention to whether the height setting of each nozzle is reasonable; Is the height of the bottom space reasonable.