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Categories of Industrial Use Smoke and Dust Removal Equipments
2025-01-27
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Mechanical Smoke and Dust Collector
A dust collector, or Dust Removal device, is equipment that separates dust particles from exhaust gases. A baghouse dust collector, also known as a fabric filter, is a type of dry, high-efficiency dust collector. It uses fabric bags as filter elements to capture solid particles from dust-laden air. The principle is that as dust particles pass through the fabric, they are intercepted by colliding with the fibers due to inertia.
Mechanical dust collectors use mechanical forces like gravity, inertia, and centrifugal force to separate dust particles from gases. Common examples include settling chambers and cyclone dust collectors
Settling Chamber (Mechanical Smoke and Dust Removal Device)
A settling chamber is the simplest type of dust removal equipment. When smoke passes into the chamber, its flow slows down because the space becomes larger. Larger dust particles, which settle faster, drop to the bottom of the chamber before the smoke exits. These particles are collected in a storage hopper at the base. Smaller dust particles that don't settle are carried out with the smoke. The dust removal efficiency is typically around 30%, so the chamber is mainly used for preliminary purification and to prepare the smoke for further dust removal by other equipment.
Settling Chamber (Mechanical Dust Collector)
A settling chamber is the simplest type of dust removal equipment. When smoke passes into the chamber, its flow slows down because the space becomes larger. Larger dust particles, which settle faster, drop to the bottom of the chamber before the smoke exits. These particles are collected in a storage hopper at the base. Smaller dust particles that don't settle are carried out with the smoke. The dust removal efficiency is typically around 30%, so the chamber is mainly used for preliminary purification and to prepare the smoke for further dust removal by other equipment.
Water Scrubber Equipment
A spray-type Dust Remover uses water sprayed as a mist through nozzles inside the device. When dust-laden air passes through the misty space, dust particles collide with, attach to, or combine with the water droplets and fall down. This type of dust remover is simple in design, has low resistance, and is easy to operate.
Its key advantage is the small gaps and openings inside the device, which allow it to handle air with high dust concentrations without clogging. The coarse water droplets it sprays eliminate the need for fine mist nozzles, making the system more reliable. Additionally, it can use recycled water repeatedly until the liquid accumulates a significant amount of particles, which simplifies water treatment systems. For these reasons, many companies still use this type of dust remover.
However, it has some drawbacks. The equipment is bulky, less effective at handling fine dust particles, and consumes a large amount of water. It is mainly used to remove larger dust particles in high-dust-concentration air. Other disadvantages include high operating costs, large initial investment, low purification efficiency, the need for dedicated personnel to manage it, high system resistance, and the risk of secondary pollution.
Water Spray Box
Polluted gas enters the spray tower from the left side. Inside, liquid mist sprays onto the gas, causing insoluble adhesive particles and dust to fall into the water. A filter then removes moisture and suspended particles from the gas, eliminating harmful substances like odors. Clean gas exits from the top, while insoluble particles and dust settle into a collection tank. Suspended particles are discharged through an overflow outlet, and collected sediments are drained through a waste outlet.
This is a typical water spray system. It achieves about 70% purification efficiency for dust particles larger than 10µm. It can also be used for kitchen smoke removal, with an efficiency of around 40%-50%.
Industrial Water Spray
This industrial water spray uses a water spray to create a thin water film on the surface of the packing material. This film comes into contact with flue gas, allowing it to absorb pollutants from the gas.
The spray liquid is distributed from the top of the tower through a liquid distributor (spray nozzles) onto the packing material, flowing down along its surface. Gas is introduced at the bottom of the tower and distributed evenly through a gas distribution device. The gas and liquid move in opposite directions through the gaps in the packing, where they come into close contact on the packing surface for mass transfer.
To prevent the gas from carrying away the spray liquid, a gas-liquid separator (essentially a packing layer without spray) is installed at the top of the tower to capture the spray liquid. The spray liquid is reused in a circulation system, with losses replenished as needed from a water tank at the bottom of the tower.
Various oil-dissolving agents can be added to the spray liquid to enhance its ability to absorb pollutants. After collection, the spray liquid is treated in an oil-water separator before being recirculated.
The Granite Stone Tower Scrubber
The Granite Tower Dust Collector, also known as the Masheet Water Film Dust Collector or Granite Water Film Dust Collector, is a cylindrical dust removal device. It is made by processing masheet (granite) into blocks and assembling them with acid-resistant mortar. Essentially, it is a water spray device that uses granite as the filling material.
The marble dust collector is a type of wet dust removal equipment. By making the circulating water alkaline, it can remove dust and desulfurize at the same time. It works like a water spray system and is effective at removing larger oil mist particles but less effective for smaller ones. This method has high operating costs, requires significant investment, has low purification efficiency, and needs dedicated management. It also has high system resistance and can cause secondary pollution. It is typically used for dust and sulfur removal in boilers.
Water Mist Hood
A water mist hood uses spray pipes to create a curtain of water, allowing the smoke to fully mix with the water. The water mist, which contains oil-removing agents, reacts with the smoke to break it down and separate the oil. This removes both the smoke and odor. To save water, the system usually recycles the water, but it needs to be replaced after some time. This is a purification method that involves placing water spray inside the range hood.
Electrostatic Precipitators
Dry Electrostatic Precipitator (ESP)
The electrostatic precipitator uses electrons emitted by the cathode in a high-voltage electric field, along with negative ions created by the electrons colliding with air molecules, to capture oil smoke particles. These particles become charged and are then attracted to the anode by the electric field, effectively removing the oil smoke.
Electrostatic precipitators are classified based on the distance between the cathode and anode into two types: wide electrode distance (typically more than 10 cm between the electrodes, with a high voltage of over 40 kV) and narrow electrode distance (typically less than 5 cm between the electrodes, with a high voltage of over 20 kV). They are used in two main settings: industrial and commercial (such as in restaurants).
Industrial electrostatic precipitator
Tower-type Electrostatic precipitator
The smoke flow in a dust collector is vertical to the horizontal direction, which is called a vertical electrostatic dust collector. The tower structure requires a high-power fan. Because the equipment is large, it usually needs to be assembled on-site, which takes a long time and is difficult. Typically, it uses a single power source.
Horizontal Style Electrostatic precipitator
In a horizontal electrostatic precipitator, the smoke flows horizontally. The horizontal design ensures smooth airflow without needing a high-power fan. It is configured with multiple units and uses a single-stage power source for each unit.
Commercial ESP Electrostatic Precipitator
Electrostatic precipitators are classified into different types based on the shape of the electrodes: honeycomb, plate-wire, and dual-mode systems that combine tubular and plate designs. The diagram is shown below:
Physical Filters
This method uses various filtering materials with a certain density to filter and purify smoke and dust.
Gas containing oil mist enters the oil mist purifier through a pipeline. First, a filter screen removes large particles of dust and liquid droplets, which helps purify the oil mist. However, the system has high operational resistance, and the filter screen needs to be replaced regularly.
Condensation Cooling Type Filter
In the electrostatic precipitator industry, this refers to a purification method that leverages the liquefaction properties of pollutants at low temperatures. It achieves purification by cooling the flue gas, utilizing the collision between the gas flow and finned tubes, as well as collecting secondary oil condensed from high-temperature flue gas. Due to the short travel distance and high wind speed, its standalone efficiency is approximately 30-40%. It is generally used in conjunction with electrostatic equipment.
Plasma Electrostatic Precipitator
The plasma purifier, also known as the low-temperature plasma exhaust gas purifier, operates under the overarching design concept of electro catalysis and incorporates three interconnected yet independent excitation systems: the microwave excitation zone, the plasma excitation zone, and the electrode plate excitation zone.
Under the influence of an applied electric field, the dielectric discharge generates a large number of high-energy electrons, which collide with pollutant molecules, causing ionization, dissociation, and excitation. This initiates a series of complex physical and chemical reactions, transforming complex macromolecular pollutants into simple, safe small molecules, or converting toxic and harmful substances into non-toxic, harmless, or low-toxicity substances, thereby achieving pollutant degradation and removal.
The average energy of the electrons generated after ionization is approximately 10 ev. By appropriately controlling the reaction conditions, it becomes possible to accelerate chemical reactions that are typically difficult or slow under normal conditions, making them exceptionally rapid.
Ultraviolet Odor Remover
In the electrostatic precipitator industry, ultraviolet (UV) light refers to the radiation in the electromagnetic spectrum with wavelengths ranging from 10 nm to 400 nm. It is classified into three categories: UVA (UV-A, wavelengths of 320–400 nm, long-wave), UVB (wavelengths of 280–320 nm, medium-wave), and UVC (wavelengths of 100–280 nm, short-wave).
UVC radiation is utilized to alter the molecular chains of oil particles. Simultaneously, this ultraviolet light reacts with oxygen in the air to produce ozone. The ozone facilitates the cold combustion of oil molecules, breaking them down into water and ozone. This process also eliminates odors within the exhaust duct. Applications are primarily focused on disinfection and deodorization.
Activated Carbon Adsorption
Activated carbon is composed of very fine carbon particles with a large surface area, and these particles contain even smaller pores—capillaries. These capillaries have a strong adsorption capacity. Due to the large surface area of the carbon particles, they can come into full contact with gases (impurities). When these gases (impurities) encounter the capillaries, they are adsorbed, leading to purification. The larger the specific surface area of the activated carbon, the stronger its adsorption capacity. Activated carbon is a non-polar molecule, making it easy to adsorb non-polar or low-polarity adsorbates. The size of the activated carbon particles, the structure and distribution of the micropores, and the surface chemical properties significantly influence its adsorption performance.
Combustion-Based Dust Remover
Catalytic Combustion Equipment (Combustion Type)
The main components of the catalytic combustion equipment include the catalytic reactor, heat exchanger, combustion chamber, heat recovery system, and the chimney for purifying exhaust gases. The primary principle is as follows: Before entering the combustion chamber, the exhaust gas is preheated by passing through the heat exchanger, then transported to the combustion chamber, where it is heated to the reaction temperature. The oxidation reaction occurs in the catalytic reactor. After purification, the exhaust gas releases most of its heat through the heat exchanger, and is then discharged into the atmosphere via the chimney.
The catalyst used in catalytic combustion equipment is primarily made from porous materials with a large specific surface area and suitable pore sizes. When organic gases pass through the catalytic layer at temperatures ranging from 300 to 450°C, oxygen and gases are adsorbed onto the catalyst surface. This allows oxygen and organic gases to come into contact and collide, increasing their reactivity. As a result, a chemical reaction occurs between the organic gases and oxygen, producing CO2 and H2O, along with the release of heat. This process converts the organic gases into non-toxic and harmless gases, achieving the purpose of emissions control.
RTO Regenerative Thermal Oxidizer / Incinerator
The Regenerative Thermal Oxidizer (RTO) works on the principle of heating organic waste gases to above 760°C, causing the VOCs in the exhaust to oxidize and decompose into carbon dioxide and water. The high-temperature gases produced by oxidation pass through specialized ceramic heat exchange media, which absorb and store heat. This "stored heat" is then used to preheat the incoming organic waste gases, thus saving fuel consumption for heating the gases. The ceramic heat exchange media should be divided into two or more chambers, with each chamber undergoing a cycle of heat storage, heat release, and cleaning in turn, operating continuously. After a chamber releases heat, a portion of the clean exhaust gas that has been treated to a qualified level is introduced to clean the chamber (ensuring a VOC removal efficiency of over 95%). Only after the cleaning process is complete can the chamber enter the "heat storage" phase again.
Composite combustion-based electrostatic precipitator
Composite type refers to the combination of two or more of the above-mentioned nine technologies used together. Common combinations include Filtration + Cooling + electrostatic precipitator, Water scrubber+ Electrostatic Precipitator, Cooling + electrostatic + UV Light+ Activated Carbon Filter, etc.