In real life, most people may never have seen a dedicated wet-desulfurization process or an air-dust separator. However, those who have studied chemistry will know that during such desulfurization processes, numerous water mists and other substances are generated. These substances are not simply water droplets—rather, they can accumulate on components like fans or heat exchangers, which are prone to corrosion. They can also adhere to flue ducts and other surfaces that easily pick up dirt. If these water mists are present, such components cannot function properly. This is because the corrosive effects of the water mist, combined with its inherently turbid nature, make it unsuitable for existence within the absorption tower.
If workers from industries with experience in desulfurization are involved, they’ll certainly have already prepared such mist eliminators at the early stages of industrial production. After all, with the assistance of this kind of equipment, there’s no need to worry about the impact of water mist on the production environment. Although this type of equipment is relatively expensive, these operators still recommend purchasing it, because it ensures that the equipment won’t be damaged by these liquid droplets. In fact, while this water mist may look similar to ordinary steam, the composition of water mist in industrial settings is far from simple. Therefore, if such mist were to remain inside the absorption tower, it would naturally be impossible to guarantee that the production process could proceed smoothly without being affected.
When it comes to ridge-type demisters, many friends may not be very familiar with them. To meet the needs of some friends, Beiqing will now share with you some key points about demisters for your learning—and also let you experience the fresh air that demisters can bring. The ridge-type demister is assembled from components such as blades, clamps, fixtures, and supports, all structured and fitted together accordingly.
Its function is to capture droplets and a small amount of dust from the flue gas, reduce water carryover in the flue gas, and prevent fan vibration. The ridge-type demister blades are the fundamental and critical components of a demister system; their performance significantly influences the overall operation of the demisting system. Ridge-type demister blades are typically made from two major material categories: polymer materials or stainless steel. There are numerous types of ridge-type demister blades. According to their geometric shape, they can be classified into zigzag-shaped and streamlined types; according to their structural features, they can be divided into two-channel blades and three-channel blades.
The typical arrangements of roof mist eliminators include horizontal, herringbone, V-shaped, and combined types. In large-scale desulfurization absorption towers, the herringbone and V-shaped configurations are commonly adopted, and these are generally installed at the flue gas outlet of the absorption tower.
The roof-type demister is used to separate liquid droplets carried by flue gas. Inside the absorption tower, it consists of two-stage roof-type demisters—upper and lower—and a flushing water system. After undergoing purification treatment, the flue gas flows through two horizontal roof-type demisters, during which the fine slurry droplets it carries are removed. The small droplets separated from the flue gas gradually coalesce into larger droplets and then slide down along the blades of the roof-type demister into the slurry pool. At the upper and lower sections of the first-stage demister and at the lower section of the second-stage demister, there is a set of header tanks equipped with nozzles. The demister cleaning water in these header tanks sequentially flushes the solid particles deposited within the demisters via the nozzles. After being washed and purified, the flue gas exits the absorption tower and finally passes through a flue gas heat exchanger and a clean flue duct before being discharged into the chimney.
1. Regarding the de-fogging power, under normal operating conditions, the flue gas concentration at the outlet of the demister should be kept below 75 mg/Nm³.
2. Regarding pressure drop, assuming that disturbances before and after the mist and dust removal device are not taken into account, the total pressure drop across the entire mist and dust removal system will be below 120 Pa.
3. It is pressure-resistant and can withstand high temperatures ranging from 80 to 95℃. The blade can operate normally under pressures below 0.3 MPa.
4. The nozzle used is a full-cone nozzle, with a spray angle ranging from 90 to 120 degrees, and it can ensure that the entire blade is fully covered.
