The method of using a scraper film evaporator to continuously treat waste acid from methanol low-pressure carbonyl process includes the following steps:
(1) Add deionized water to the waste acid material, which accounts for 0.5% to 2% of the waste acid content by mass, and mix it thoroughly with the waste acid.
(2) Transfer the waste acid mixed with deionized water into a scraper film evaporator for transpiration treatment.
(3) The liquid in the storage tank is sent to the distillation tower for distillation. Crude acetic acid with a mass content greater than 90% is distilled at the top of the distillation tower and returned to the acetic acid production equipment for further distillation. If there is acetic acid, dark propionic acid is separated at the bottom of the distillation tower. The dark propionic acid is sent to the second distillation tower for distillation, and colorless propionic acid with a mass content of 99.5% or more is distilled at the top of the second distillation tower.Thin film evaporator is a type of evaporator characterized by the flow of material liquid along the heating tube wall to form a film, generating heat and evaporation. It has high heat transfer efficiency, fast evaporation speed, and short material residence time, making it particularly suitable for the evaporation of heat sensitive materials. According to the reasons for film formation and flow direction, it can be divided into three types: rising film evaporator, falling film evaporator, and scraping film evaporator. The thin film evaporator device consists of three components: evaporator, vapor-liquid separator, and preheater, as well as a rising film heat pipe heat exchanger. This evaporator has the characteristics of strong production capacity, high efficiency, and short material heating time, and is suitable for dilute solution concentration in industries such as pharmaceuticals, food, and chemicals
Thin film evaporator is a type of evaporator characterized by the flow of material liquid along the heating tube wall to form a film, generating heat and evaporation. It has high heat transfer efficiency, fast evaporation speed, and short material residence time, making it particularly suitable for the evaporation of heat sensitive materials.