I. Overview
The waste gas purification tower is a crucial piece of equipment in the environmental protection field, which is used to purify the waste gas generated during industrial production processes. It can effectively remove harmful substances in the air, such as waste gas, dust, and odors, and is widely applied in multiple industries including chemical engineering, petroleum, metallurgy, electronics, and medicine. Depending on different purification principles and structures, it can be classified into various types, such as plate towers, bubble absorption towers, spray towers, packed absorption towers, falling film absorption towers, and biological purification towers.
II. Working Principle
Pretreatment Stage: When the waste gas containing pollutants enters the purification tower, it first undergoes preliminary pretreatment. Usually, a filtering device is used to remove large particles of dust and impurities to prevent them from interfering with the subsequent purification process.
Physical Purification Stage: There are multiple spray layers inside the purification tower. High-pressure nozzles evenly spray specific purification liquids into the waste gas. The purification liquid fully contacts the waste gas, and through collision, adsorption and other effects, it captures particulate matter and soluble pollutants in the waste gas.
Chemical Purification Stage: The purification liquid used in the purification tower is specially formulated according to different pollutants. For acidic waste gas, an alkaline solution is used for neutralization, and for waste gas containing organic pollutants, a solution with an oxidizing effect is used for decomposition. Through chemical reactions, harmful substances are converted into harmless substances or forms that are easy to handle.
Liquid Circulation and Waste Gas Emission: There is a liquid collection tank at the bottom of the purification tower, which collects the treated liquid and the captured pollutants. The liquid can be recycled and pumped to the spray layer again after treatment. After purification treatment, the waste gas is discharged into the atmosphere through the exhaust port at the top of the purification tower. At this time, the waste gas has met the national emission standards.
III. Performance Characteristics
High Purification Efficiency: For example, the acid (alkali) mist waste gas purification tower adopts a two-stage counter-spraying method. The packing has a large specific surface area, and the gas ratio determined through experimental research ensures stable performance. The purification efficiency for various concentrations of acid (or alkali) waste gas can reach 85% - 95%.
Wide Applicability: It can purify multiple pollutants simultaneously and can handle organic waste gas discharged during the production processes of multiple industrial sectors such as chemical engineering, light industry, and printing and dyeing, as well as tail gases of sulfuric acid, nitric acid, hydrochloric acid, and acidic gases such as sulfur oxides, nitrogen oxides, and carbon oxides.
Convenient Operation: It is suitable for the treatment of waste gas discharged continuously or intermittently. The process is simple, and management, operation, and maintenance are quite convenient and will not affect the production in the workshop.
Low Pressure Drop: It has a large operating flexibility and excellent demisting performance. Based on ensuring a sufficient gas-liquid contact area, packing varieties and structural forms with aerodynamic characteristics are adopted to make the equipment have a relatively small resistance under the rated air volume.
Diverse Materials: The tower body can be made of materials such as FRP/PP/PVC according to the actual situation, which has good corrosion resistance and high strength, and can adapt to different working environments.
IV. Structural Components
Tower Body: It is the main structure of the waste gas purification tower and is fabricated according to different material and process requirements, providing the space and place for waste gas treatment.
Packing: It is the core of the packed tower, providing the contact surface between the gas and liquid phases in the tower. The packing and the tower structure determine the performance of the tower. For example, using efficient and low-resistance Pall rings and other packings can increase the gas-liquid contact area and improve the mass transfer efficiency.
Spray System: It includes spray layers and nozzles, which evenly spray the purification liquid into the waste gas to achieve full contact between the gas and the liquid, and it is a key component in the purification process.
Demister: It is used to collect the droplets in the purified waste gas to prevent the liquid from being carried out of the tower, improving the quality of the waste gas emissions.
Circulation System: It consists of a circulation pump and a liquid collection tank, realizing the recycling of the purification liquid and ensuring the continuous and stable progress of the purification process.
Air Intake and Outlet Devices: They include air inlets and outlets, enabling the waste gas to enter the purification tower evenly and discharge the purified waste gas into the atmosphere.
V. Application Cases
In electroplating factories, the electroplating process generates waste gas containing acid mist. By installing a waste gas purification tower and using an alkaline solution as the absorption liquid, through the action of spraying and the packing layer, the acid mist waste gas fully contacts the alkaline solution and undergoes a neutralization reaction, effectively removing the acid mist in the waste gas, making the emitted waste gas meet the environmental protection standards and reducing the harm to the surrounding environment and the health of employees. In pharmaceutical factories, the organic waste gas and odorous gases generated during the production process are treated by waste gas purification towers. Through processes such as activated carbon adsorption and catalytic oxidation, the organic pollutants are decomposed and removed, eliminating the odors and achieving the standard emissions of waste gas.
In conclusion, the waste gas purification tower plays an important role in industrial waste gas treatment with its excellent performance and wide application range, contributing significantly to environmental protection and the sustainable development of industries.
