Learn about the wood-fired boiler exhaust gas treatment system:
Today, some companies to save costs should reuse the materials used to burn boilers, especially wood companies. Most of the emissions from wood-burning boilers come from the burning of wood, coal, etc. In which, nearly 99% of the combustion products are substances such as nitrogen, water vapor, CO, CO2,… besides in the process. The combustion process generates a large amount of soot, ash and a number of harmful gases that directly affect human health and organisms such as CO, NOx, SOx, dust.
The wood-burning boiler exhaust gas treatment system operates according to the following process:
– Exhaust smoke, after leaving the combustion chamber through the exhaust pipe, is transported by a centrifugal fan to transport air through the wet filter device. Here ash and soot are thoroughly filtered. The exhaust gas is then directed to the absorption tower.
– The absorption tower is designed to absorb harmful gases generated from the combustion of fuel such as CO, SOx, NOx … by the lime milk solution provided from the metering pump system.
– Liquid absorption of harmful gases is the process of dissolving gases in liquids when they come into contact with each other. The structure of this process is divided into three steps:
– Diffusion of gaseous pollutant molecules in the exhaust gas to the surface of the absorbent liquid.
– Penetrates and dissolves the gas on the surface of the absorbent.
– Diffusion of the dissolved gas on the surface of the separator deep into the interior of the absorbing liquid.
– At the absorption tower of the wood-burning boiler exhaust gas treatment system, the lime solution is continuously pumped from the top of the tower to the contact plate layers, and the exhaust gas containing CO, SOx, NOx is led from the bottom. The process of contact between the gas phase and the water phase helps the absorption process to take place easily. The absorption process occurs in the tower (isothermal absorption process): – The gas coming out of the absorber is clean air that continues to be pushed into the chimney by the exhaust fan and discharged. Absorbent solution is pumped circulating from the reservoir to the absorber. Ash and soot are periodically disposed of, and the adsorbent solution is periodically discarded.
How many methods of treating wood-burning boiler exhaust gas?
Treatment of wood-burning boiler flue gas by dispersal method:
Calculate the emission of pollutants into the environment without treatment by raising the exhaust chimney to dilute the exhaust smoke into the air.
This method is suitable for waste sources that are not highly polluted, only needing to be diluted with air to meet the emission standards to the environment.
Treatment of wood-burning boiler flue gas by absorption method:
Principle: for flue gas in contact with liquid, these gases are either dissolved into the liquid or converted into components.
The effectiveness of this method depends on the contact surface area between the gas phase and the liquid phase, the contact time, the concentration of the absorbing medium, and the reaction rate between the absorbent and the exhaust gas.
The absorption method is widely used in the reduction of SO2, in the exhaust gas from firewood, coal burning, oil and from smelters; degassing H2SO4 from the chemical industry; degassing H2S from the natural gas production and oil refining industry; Chlorine gas from chemical production; halogens, CO2, NO2 and dust from other technological processes; HCl, NH3 from metal plating process…
Waste gas treatment of wood-burning boilers by adsorption method:
Adsorption is the process of selectively attracting components in the gas or liquid phase to the surface of a solid. he adsorption process is carried out by contacting two insoluble phases, the solid phase (the adsorbent) with the gas or liquid phase. The adsorbent will go from gas or liquid phase to solid phase until the concentration between the two phases reaches equilibrium.
The effectiveness of the adsorption method is highly dependent on the surface area of the solid phase and the adsorption capacity of the selected material. Activated carbon is one of the commonly selected materials as an adsorbent.
Scope of application: The adsorption method is often used in the case of recovering alcohol vapors from alcohol storage, cleaning furnace exhaust …
Waste gas treatment of wood-burning boilers by heat catalysis method:
This method uses heat exchanger surfaces as a catalyst to change the composition of the exhaust gas before it is released into the environment.
Incineration method:
Principle: Direct combustion of toxic gas vapors to be treated to produce combustion products other than non-toxic or less toxic gases and water vapor.
KS – Boiler specializes in manufacturing, installing and maintaining industrial boilers:
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