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Distillation column system

I. Distillation column system composition and arrangement

The distillation column system consists of a simple distillation column, a reboiler, a condenser, a reflux tank, etc., generally in the order of the process, and arranged as close as possible to form an independent operating system. The same kind of equipment is arranged centrally, such as the condenser is generally arranged on the three-story floor, and the reflux tank is arranged in the second.

On the floor, the reboiler is installed at the bottom of the distillation column, and the pump is placed on the floor. This is not only neat, beautiful, but also easy to operate. Due to the special nature of the reboiler, the equipment and piping associated with it must be carefully designed.

Second, distillation column system operation

The liquid at the bottom of the column is heated by a reboiler to partially vaporize it, and enters the column from the bottom reboiler into the column, and is in countercurrent contact with the descending liquid, and the volatile (low boiling) component in the falling liquid is continuously turned to In the vapor transfer, the less volatile (high boiling point) component of the vapor is continuously transferred to the descending liquid, and the vapor is continuously connected.

Near the top of the column, the higher the concentration of volatile components, the closer the falling liquid is to the bottom of the column, and the more volatile components are enriched to achieve the purpose of component separation. The rising vapor at the top of the column enters the condenser, a portion of the condensed liquid is returned to the top of the column as reflux, and the remainder is sent as a distillate. The liquid flowing out from the bottom of the column, a part of which is sent to the reboiler to heat the return column, and the other part of the liquid is taken as the residual liquid.

Third, thermosiphon reboiler

1, the principle of thermosiphon reboiler

The thermosiphon reboiler uses the liquid level of the distillation column and the head difference of the reboiler liquid level as the power to drive the liquid gravity circulation flow, so that the liquid at the bottom of the distillation column flows to the reboiler. A portion of the liquid is vaporized in the reboiler and returned to the column to effect vapor and liquid separation. In order to ensure the normal operation of the reboiler, it must be ensured that there is a certain pressure difference to overcome the pressure drop in the pipeline, the reboiler and the static pressure of the two phases.

2, thermosiphon reboiler installation height requirements

The liquid at the bottom of the distillation column flows into the pipe, and the pressure is higher as it goes upward. If the pipe in which the liquid rises is high, the pressure is reduced to cause bubbles in the pipe (consisting of air or other constituent gases). The height of the siphon action is determined by the generation of bubbles. Because the bubbles will break the liquid, the bubbles

The force between the gas molecules at the end is reduced to zero, thereby destroying the siphon effect. The thermosiphon reboiler installation position is not as low as possible.

3, vertical thermosiphon reboiler special requirements

If the vertical thermosiphon reboiler is operated under vacuum, it is not suitable for liquids with a high viscosity and solid materials, and also requires a high height of the column skirt. The horizontal thermosiphon reboiler does not require high liquid level and pressure drop, and is more suitable for vacuum distillation. The distillation column is an efficient and energy-saving distillation column type. According to the designed parameters, various specifications can be designed to meet the requirements of different production capacities.