The structural types of gas-liquid phase reaction reactors are numerous. In principle, a comprehensive consideration should be given to the selection, combining reaction kinetics and transfer requirements. The following factors are generally to be considered when making a selection:

When the bubble size is significantly larger, for rapid reaction and diffusion control, if the resistance is on the gas film side, a device with the gas phase as the continuous phase should be chosen, and it is preferable to have good turbulent conditions and a large interface, such as spray towers and packed towers. If the resistance is on the liquid film side, a tray tower is more suitable; in this case, the liquid phase is the continuous phase, and there is an adequate liquid hold-up to facilitate mass transfer in the liquid film.

For systems with a very small gas-liquid ratio, where the liquid phase reaction is slow and the process is controlled by a diffusing liquid film or kinetic control, with liquid phase back mixing having no effect on the reaction, a bubble column or a stirred bubble column with a liquid phase as the continuous phase and sufficient liquid hold-up, as well as a simple structure, should be selected for such systems.

3. In cases of a consecutive reaction where the intermediate product is the desired product, the reaction is kinetically controlled, or for non-ideal reactions where diffusion control is present, it is undesirable to have significant back-mixing. It is recommended to use co-current multi-stage bubble columns or multi-stage bubble columns with transverse baffles.

4. In cases where a large interfacial area is required for diffusion control or when the mass transfer coefficient needs to be maximized, as well as in gas-liquid reactions mixed with a certain amount of solid particles, mechanical agitation-equipped reaction equipment must be used.

5. A trickle bed reactor can be used for gas-liquid reactions utilizing solid catalysts, especially when the reaction needs to occur on the catalyst surface or through internal diffusion within its surface, and when the reaction heat can be mitigated by adiabatic temperature rise.

6. For gas-liquid reactions, both co-current and countercurrent tubular reactors are not commonly used in industry. This type of reaction is typically employed where the chemical reaction itself is fast-paced and there is a high demand for heat transfer area per unit volume.