What Is a Wet Scrubber?

Wet scrubber is a dust removal device designed and manufactured using wet dust removal technology. It is also called a wet duster or a scrubber. It can effectively remove liquid or solid particles with a diameter of 0.1-20 microns from the air stream, and at the same time, it can remove some gaseous pollutants. It has the advantages of simple structure, small footprint, convenient operation and maintenance, and high purification efficiency. It can handle high-temperature and high-humidity airflow, and minimize the possibility of fire and explosion. The fundamental difference between a wet dust collector and a general gas absorption tower is that the latter requires the washing liquid to form fine droplets to facilitate gas absorption, while the former does not have this requirement.

The dust removal device designed and manufactured by wet dust removal technology is called wet type

The dust removal principle of the wet type dust collector belongs to the short-range mechanism. The dust-containing gas in the dust collector has the following process: the dust particles contact the pre-dispersed water film or mist liquid phase. Water film. Larger particles (such as larger than 1mm) are captured when they collide with water droplets. The capture efficiency depends on the inertia and diffusion of the particles. Because of the relative movement between the water droplet and the airflow, and because of the ambient air film around the water droplet, when the gas is close to the water droplet, the gas changes its direction to bypass the water droplet, and the dust particles are affected by the inertial force and diffusion, maintaining the original trajectory and water droplet. Collided. In this way, dust particles may collide with water droplets within the range, and then condense into large particles due to the action of water, which is carried by the current. This shows that the water droplets are small and numerous, and the specific surface area is increased, and there are more opportunities to contact the dust particles, and the collision, diffusion, and condensation efficiency are also high. The larger the specific gravity of the dust particles, the relative speed of the particle size and the water droplets, the higher the collision and cohesion efficiency; the greater the viscosity, surface tension of the liquid, the larger the water droplet diameter, the uneven dispersion, and the lower the collision and cohesion. Experiments and production experience show that hydrophilic particles are easier to trap than hydrophobic particles because hydrophilic particles can easily pass through water films. In addition, when the diameter and density of dust particles are small, the dust removal efficiency is significantly reduced. In order to solve the problem of low efficiency of hydrophobic dust and fine particles, certain agents can be added to the water to improve the dust removal efficiency. ^[1]

Structure of wet dust collector: Although the structure of different types of wet dust collectors is quite different, it is generally composed of dust introduction device, water introduction device, water and gas contact body, droplet separator and sewage (mud) discharge device. .

There are different types of wet dust collectors from different angles.

(1) According to the structure type, it can be divided into

Water storage type: a certain amount of water is built in, and high-speed dust-containing gas impacts to form water droplets, water films and bubbles, and the dust-containing gas is washed, such as impulse type dust collector, water bath type dust collector, horizontal cyclone water film dust collector .

Pressure water spray type: Supply pressurized water into the dust collector, and use the spray or spray to generate water droplets to wash the dust-containing gas; such as Venturi dust collector, foam dust collector, packing tower, turbulent tower, etc. .

Forced Rotary Spraying: Forced rotating spraying with mechanical force, or rotating the blades, so that water droplets, water films and bubbles are formed in the water supply, and the dust-containing gas is washed. Such as rotary spray type dust collector.

(2) According to the energy consumption, it can be divided into

Low energy consumption type: the resistance is below 4000Pa, and the dust removal efficiency can reach 90%. This type of dust collector includes spray type, water bath type, impulse type, foam type, cyclone water film type dust collector.

High energy consumption type: resistance is above 4000Pa, and it is highly efficient for fine dust. This type mainly refers to Venturi dust collector.

(3) According to the gas-liquid contact method, it can be divided into

Integral contact type: Dust-containing air flows into the liquid and is washed, such as self-excited type, cyclone water film type, foam type and other dust collectors;

Dispersive contact type: spray into the air stream containing dust, and the dust particles collide with water droplets and liquid film and are captured, such as Venturi tube, spray tower, etc.

Preventing air flow from carrying droplets out of the wet dust collector is of great significance for ensuring the operation of the dust removal system. Common dehydration devices are gravity dehydrators, inertial dewaterers, cyclones, elbows

Wet dust removal is to bring the exhaust gas into close contact with liquid (usually water),

Washing and purification of various industrial dust, organic odor, absorption and purification of acid and alkali exhaust gas, boiler flue gas desulfurization, die casting machine, central furnace, incinerator and other flue gas, chemical and pharmaceutical, food processing, metallurgy, casting, carbon materials , Machinery processing, building materials, tablet presses, granulators, mixers, ingredients, mixes, shakers and other industries.
Compared with other dust collectors, wet dust collectors have the following advantages:
(1) Wet dust collector can be used to purify harmful gases together, and it is suitable for handling high temperature, high humidity smoke and sticky dust. In this case, the selection of dry dust collectors is often restricted by various conditions;
(2) In the case of equal energy consumption, the dust removal power of the wet dust collector is higher than that of the dry type. The high-energy wet dust collector (Venturi dust collector) still has a high dust removal power for dust as small as 0.1 m;
(3) The layout of the wet dust collector is simple, low investment at one time, and small footprint.