During the process of socio-economic development and industrialization, many factories and enterprises went into production and operation. This process causes many sources of wastewater discharge, emissions that pollute the environment and affect the health of people and the community.
What is emission treatment, dust treatment, odor treatment?
Emission treatment is the process of treating exhaust gas, smoke and dust generated in the production process of factories and companies. Depending on the specific industry of each factory, the amount of emissions released into the environment has different properties and components.
Therefore, it is necessary to have an appropriate emission treatment plan and technology to remove the pollutant components and avoid polluting the plant and the surrounding environment. The construction of a suitable and efficient exhaust gas treatment system will help the production and business activities of enterprises meet the requirements of environmental protection and worker health and safety.
HOA PHAT ECO – ENVIRONMENTAL CONTRACTOR SPECIALIZING IN DESIGN, CONSTRUCTION, INSTALLATION OF EMISSION TREATMENT SYSTEM, DUST AND ORDOR TREATMENT FOR THE FOLLOWING INDUSTRY:
– Treatment of boiler exhaust gas
– Treatment of paint dust exhaust gas
– Treatment of waste gas incinerators
– Treatment of odors in wastewater treatment systems
– Treatment of emissions from plating, metal processing
– Treatment of cement factory emission
– Treatment of the smell of aquatic plants, cattle and poultry slaughter stations
– Handling industrial dust, wood dust, cloth dust
– Treatment of the smell of chemical factories, treatment of rubber odors, treatment of landfill odors
– Handling solvent vapors, acid vapors
– Repair, upgrade and renovate the emission treatment, odor treatment, and dust treatment systems
The capacity of Hoa Phat Eco Company in the field of design, construction and installation of emission treatment, odor treatment, and dust treatment systems:
– Solution, service package, turn-key
– Consulting solutions and technologies suitable to the specific characteristics of each type of exhaust gas, odor, and dust
– Effectively and thoroughly handle the pollution indicators and components, completely solve the problem of emissions and odors that affect the production and business process.
– A team of consultants, designers, and installers have in-depth knowledge with many years of experience in the field of exhaust gas treatment, odor treatment
– Ensure reasonable and competitive investment costs, stable and effective system operation
– Package warranty, maintenance and repair solutions for exhaust systems
– Ensure to meet complex technical requirements, progress requirements as well as aesthetics and quality for each exhaust gas treatment project.
CURRENT METHOD AND TECHNOLOGY OF EMISSION TREATMENT:
Depending on the characteristics of each type of emission, it will contain different components and pollutants. To thoroughly treat these components requires a combination of appropriate processing methods and technologies.
I. Emission treatment by mechanical method
1. Use cyclon:
As a device in many emission treatment systems, it is a pre-treatment stage to separate most of the large amount of dust in the emission stream.
Particle size is a fundamental parameter in the design of cyclon dust separators. The choice of dust separator depends on the dispersion composition of the separated dust particles. In dust separators, the speciﬁc size of dust particles is a quantity of their settling velocity such as a quantity of settling diameter.
Because industrial dust particles have very different shapes (spherical, rod, fiber, ); so if the same mass will settle at different velocities, the closer the particle is to the spherical shape, the faster it will settle. The maximum and minimum sizes of a block of dust particles characterize their dispersion distribution range.
2. Use a dust filter bag
Dust filter bag is one of the most widely used equipment in emission treatment works, due to its easy construction, high treatment efficiency and relatively reasonable price.
The principle of the dust filter bag is as follows: for the air and dust to pass through a filter cloth, initially the dust particles larger than the gap between the fibers will be retained on the surface of the cloth according to the sieving principle, the particles are smaller. adhesion on the surface of the filter cloth due to impact, gravity and electrostatic attraction, gradually the collected dust layer thickens to form a filter aid film, which holds even very small dust particles. .
Filtration efficiency reaches 99.8% and even very small particles are filtered thanks to the filter aid layer. After a period of operation, the dust layer will be very thick, making the resistance of the filter too great, the efficiency of exhaust gas treatment will increase, but the speed and flow of exhaust air through the filter cloth will decrease significantly, so we must stop the emission to pass and proceed to remove the dust layer on the fabric surface.
This operation is called reverting filterability. The filter cloth is usually sewn into a circular filter bag with a diameter of D=125~250 mm or larger and a length of 1.5 to 2 m. It is also possible to sew into a rectangular box with a width of b=20~60mm; Length l=0.6~2m. In one device there can be tens to hundreds of dust filter bags.
3. Use electrostatic precipitator
Electrostatic precipitator is often used for exhaust gas treatment systems that generate a lot of fine dust such as exhaust gas treatment systems of thermal power plants, coal-fired boilers…
The working principle of the device is as follows: When the air and dust flow through a strong enough DC electric field, the gas will be ionized and adhere to the surface of the dust particles, making the surface of the dust particles electrified. Due to the effect of the electric field force, the charged particle will be attracted to the opposite pole (usually the anode). When hitting the electrode, the dust particles are electrically neutralized and fall to the bottom to discharge the dust.
The DC electric field in the device usually has a very high voltage, from 11 KV to 80KV depending on the type of device. In an electric field, a dust particle with a diameter of 0.1mm will be charged up to a maximum in about 1s. Therefore, the time of air flow through the device is from 2 to 8 seconds depending on the device. Treat exhaust gas by electrostatic precipitator with very high efficiency up to 99.8% when the initial concentration reaches 7 g/cm3. It is often used to purify the air after the pre-filtration stages by settling chamber and Cyclon. It also has the advantage of purifying exhaust gases at very high temperatures without cooling the exhaust gases.
This device is also a low power consumption device of 0.2 KW / 1000m3/h because of its low resistance (10 – 20 kg/m2). However, the concentration of explosive substances in the exhaust gas such as CO, coal dust, etc, … should be strictly controlled to avoid detonation due to the ionized gas stream generating sparks.
II. Emission treatment with chemical menthod
1. Emission treatment by absorption method
Absorption of waste gas by chemical method is a method of using liquids and solids as raw materials to absorb toxic gases from the production process of the factory. This is the process of transferring harmful gases to be treated into the liquid phase. Thanks to the dissolution process, they come into contact with each other. During absorption, a chemical reaction occurs.
In the absorption tower, the gas flow will be distributed to the device at the bottom and the absorption solution flow will be distributed in the top-down direction. This solution is transported by centrifugal pump from the absorption solution tank, through the distributor to form small liquid droplets, evenly sprayed into the device. The absorption tower in exhaust gas treatment has a two-stage structure, each floor plays a role in the entire treatment process.
At the lower part of the treatment device, the absorbed solution is distributed by a dedicated gas distribution system (injector) evenly throughout the entire volume of the tower, the exhaust gas flows from the bottom up to contact with the wastewater, here all the dust in the emission is retained, and part of the pollutants is absorbed here.
At the upper floor of the tower, an absorption buffer layer is arranged to increase the contact between the emission and the absorbing solution. At the absorption buffer materials, the absorbent solution forms water films, which are in contact with the emission stream, and the pollutants in the exhaust gas are thoroughly absorbed here.
Emission treatment systems by absorption method are divided into 2 types:
a.Treament of high temperature emission
Including emissions from incinerators such as garbage incinerators, boiler exhaust gases, emissions from aluminum smelters, copper furnaces, etc. These gases are characterized by high temperature, the main components of these gases are COx, SOx, NOx, Fluorine… when reacting with water in the absorption solution, they will produce acids with highly corrosive properties.
Depending on the type of gas, there is corrosiveness with each type of material separately. When designing and selecting materials, designers must pay attention to the following considerations:
– Emission of copper furnace and aluminum furnace after absorption has the ability to corrode stainless steel. Therefore, the best treatment tower should be coated with acid-resistant bricks.
– Emission from other incinerators can be made with CT3 Steel and then coated with heat-resistant and acid-resistant bricks.
– The buffer material used in this flue gas treatment tower is usually porcelain gasket.
– Another important note is that in the high-temperature furnace flue gas treatment system, it is imperative to have a pH neutralization system and a circulating solution cooling tower system.
b. Treatment of low temperature emission
Includes gases that must be generated from sources such as: emission from acid baths, metal cleaning tanks, plating baths, exhaust gases from combustion processes but without fire or with low heat generation such as emissions in the melting process. plastic particles, emissions from the packaging cutting process… With this emission characteristic, the optimal material for the device body is PP or Composite material.
2. Emission treatment by adsorption
Emission treatment by adsorption is a treatment process based on gas separation by pressure of some solids with some gases present in the gas mixture. In the process, the pollutant gas molecules in the exhaust gas are trapped on the solid material. The application of adsorption method to treat gas sources with small content of gas and vapor impurities. To clean and dry the air, separate the gas mixtures. Or vapor form individual molecules, conducting the process of heterogeneous influence on the surface. The solid material used in this process is called the adsorbent. The gas trapped in the adsorbent is called the adsorbate.
Chemical gas adsorption is a method by which gases are adsorbed. Due to the chemical reaction with the adsorbent, the intermolecular forces in this case are stronger than in the physical adsorption.
a. Emission treatment by activated carbon adsorption tower:
Commonly used in the treatment treatment of industrial printers, small capacity heating chambers The characteristics of the emission treatment system by the adsorption method is that the exhaust gas flow is small, and the pollutant concentration in the emission is low.
b. Adsorption by solid materials capable of chemically reacting with the emission
This method is usually only applied when treating exhaust gases with only a certain pollutant composition, or used in exhaust gas recovery, gas drying (e.g. oxygen, natural gas) and adsorption methods by-products of heavy (polar) from natural gas.
III. Treatment of emission by biological method biofilter
Made from familiar materials, low cost but high efficiency, biofilters system is designed to achieve all three factors: low operating costs, low maintenance costs and easy upgrade whenever required changes.
The Biofilters system is a biological treatment system capable of removing 90-98% of odors. Hazardous gases are drawn from the source by a blower and the air is forced through the humidification system to raise the relative humidity (RH) to >95%. The water/absorbent solution is pumped and recirculated. The water loss due to evaporation is automatically refilled by electronic level sensor and solenoid valve.
The gas diffuses through the moist organic filter media where microorganisms metabolize organic matter and other odorous compounds. Moisture in the filter bed is maintained and controlled by the irrigation system. Deodorized and decontaminated air is released into the atmosphere. The system is designed to be able to add an activated carbon processor at a later stage if required. The scraper can be easily opened for maintenance.
With the sharing of general knowledge and explanations on emission treatment, Hoa Phat Eco wishes that customers better understand the importance of the emission treatment system for environmental protection in the process production and business processes of enterprises and factories.
To invest in building a system of odor treatment, emission treatment or dust treatment at a reasonable cost and suitable for your factory, please contact Hoa Phat Eco Company for assistance detailed technical advice.
We are committed to providing optimal emission treatment services, appropriate technology, ensuring to thoroughly solve the problem of dust, emissions, and odors in the production process of factories and enterprises.