Tower equipment is one of the most important equipment in chemical, petrochemical, and refining production. It can enable close contact between gas (or vapor-liquid) or liquid-liquid phases, achieving the purpose of mass and heat transfer between phases. Common unit operations that can be performed in tower equipment include distillation, absorption, desorption, and extraction. In addition, cooling and recovery of industrial gases, wet purification and drying of gases, as well as humidification and dehumidification that combine gas-liquid two-phase mass and heat transfer. After long-term development, tower equipment has formed a variety of structures to meet various special needs.