1. Introduction to the Function of a Defogger
The demister is used to separate liquid droplets carried by flue gas. Inside the absorption tower, it consists of two-stage demisters—either horizontal or diamond-shaped—as well as a flushing water system that includes pipelines, valves, nozzles, and other components. After undergoing purification treatment, the flue gas flows through two stages of horizontal demisters, where 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 demister blades into the slurry sump. At the upper and lower sections of the demister, as well as at the lower part of the second-stage demister, there is a set of header tanks equipped with nozzles. The demister cleaning water in these header tanks is sequentially sprayed through the nozzles to flush away solid particles deposited inside the demister. 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.
2. The mist eliminator body itself is assembled from structural components such as mist eliminator blades, clamps, fixtures, and supports.
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 mist eliminator blades are the fundamental and critical components of the mist eliminator; their performance significantly influences the overall operation of the mist elimination system. Mist eliminator blades are typically made from two major categories of materials: polymer materials (such as polypropylene and FRP) and stainless steel (such as 317L). There are many different types of mist eliminator blades. According to their geometric shapes, they can be classified into zigzag-type (a, d) and streamlined-type (b, c); according to their structural features, they can be further divided into two-channel blades and three-channel blades.
The common arrangements for demisters include horizontal, herringbone, V-shaped, and combined types. Among large-scale desulfurization absorption towers, the herringbone arrangement is widely adopted, as are V-shaped or combined arrangements (such as diamond-shaped or X-shaped). The horizontal type is typically used in the horizontal section at the outlet of the absorption tower.
