Reboiler

A reboiler (also called a reboiler, as the name implies) is a device that vaporizes liquid again. Its structure is quite similar to that of a condenser; the difference is that a condenser is used for cooling, while a reboiler is used for heating and vaporization.

Reboilers are mostly used in conjunction with fractionating towers: a reboiler is a special heat exchanger that can exchange heat and has a vaporization space. The liquid level of the material in the reboiler is at the same height as the liquid level in the fractionating tower. The liquid phase is supplied from the bottom line of the tower into the reboiler. Usually, 25-30% of the liquid phase in the reboiler is vaporized. The vaporized two-phase flow (gas-liquid mixture) is sent back to the fractionating tower: the gas-phase components returning to the tower move upward through the trays, while the liquid-phase components fall back to the bottom of the tower.

When the material is heated in the reboiler, it expands and even vaporizes, resulting in a decrease in density. Thus, it leaves the vaporization space and returns to the tower smoothly. For the gas-liquid two-phase flow returning to the tower, the gas phase moves upward through the trays, and the liquid phase falls to the bottom of the tower. Due to the effect of static pressure difference, the bottom of the tower will continuously replenish the part of the liquid level that has been evaporated.