FAQ

The selection primarily requires the following parameters: First, the nature of the exhaust gas, including pollutant composition, concentration, and whether it contains dust; second, the treatment air volume, measured in cubic meters per hour; third, the exhaust gas temperature and humidity; fourth, the required purification efficiency and the applicable emission standards; fifth, the on-site installation space, including height and footprint limitations; sixth, material preferences and flammability rating requirements. Providing these parameters allows for matching the cabinet size, adsorption layer count, and activated carbon loading, supporting custom non-standard designs. If the parameters are incomplete, an approximate air volume and exhaust gas type can be provided first, and technical personnel will assist in refining them.

The selection primarily requires the following parameters: First, the nature of the exhaust gas, including pollutant composition, concentration, whether it contains viscous substances or dust; second, the treatment air volume, measured in cubic meters per hour; third, the exhaust gas temperature and humidity; fourth, the on-site installation space, including height and footprint limitations; fifth, the required purification efficiency and the applicable emission standards; sixth, material preferences. Providing these parameters allows for matching the tower diameter, number of swirl blade layers, and circulating water pumps. Standard tower diameters cover φ800 to φ3000, and non-standard designs are available for special conditions.

PP ducts and PVC ducts each have their own characteristics. PP ducts offer better temperature resistance, excellent chemical corrosion resistance, good flexibility, and are non-toxic and recyclable, making them suitable for conveying acidic, alkaline, and slightly temperature-raised gases. PVC ducts are more cost-effective and have good rigidity, but their temperature resistance and corrosion resistance are relatively weaker, and they may produce harmful gases when burning. In the field of exhaust gas treatment, especially when conveying corrosive acidic and alkaline exhaust gases, PP ducts are more commonly used and reliable. The specific choice should be comprehensively considered based on the composition of the exhaust gas, temperature, and budget.

PP elbows and PP ducts are made of the same PP polypropylene or PPs flame-retardant polypropylene material, with identical material composition. The advantage of the same material is that they have the same coefficient of thermal expansion, ensuring that the expansion and contraction of elbows and ducts are consistent under temperature changes. This prevents loosening or leakage at connection points due to thermal expansion and contraction, making the connection more reliable. Additionally, the same material offers the same acid and alkali corrosion resistance, making it suitable for conveying corrosive gases. When used together, elbows and ducts form a unified material ventilation system, ensuring consistent service life.

PP processing ducts primarily use flange connections. Flange plates are welded to both ends of the duct body, and the two flanges are connected with bolts and sealed with gaskets, offering excellent sealing performance and secure connections, making them suitable for large pipe diameters and applications requiring frequent disassembly. For smaller pipe diameters, socket connection can also be used, where one end of the duct is inserted into the socket of another duct, sealed with sealant, and offers easy installation. When connecting ducts to equipment or fans, it is recommended to use flexible connections to reduce vibration transmission. Specific connection methods should be selected based on pipe diameter, pressure, and maintenance requirements.

The absorbent is determined based on the composition of pollutants in the exhaust gas. For treating acidic exhaust gas, alkaline absorbents such as sodium hydroxide solution are typically used; for treating alkaline exhaust gas, acidic absorbents such as dilute sulfuric acid solution are used; for treating water-soluble organic exhaust gas, water or corresponding solvents can be used. The concentration and circulation rate of the absorbent need to be designed according to the exhaust gas concentration and treatment air volume. During operation, the pH and concentration of the absorbent should be monitored regularly, and chemicals should be replenished or circulating liquid replaced in time to ensure stable purification effects. The absorbent should be avoided from being discharged arbitrarily, and it needs to be discharged or recycled after being treated in accordance with environmental protection requirements.

The tower is mainly composed of an air inlet, a water tank, a packing layer, a spray layer, a demister, and an exhaust stack from bottom to top. The lower water tank stores the absorbent, equipped with interfaces for water replenishment, wastewater discharge, overflow, and chemical dosing. The packing layer is filled with multi-faceted hollow balls or Raschig rings to increase gas-liquid contact area. The spray layer is equipped with two or more layers of nozzles to evenly spray the absorbent onto the packing cross-section. The upper mesh demister removes liquid droplets carried by the outlet gas, protecting the downstream fan. The tower is also equipped with a circulating pump, pipes, valves, manholes, sight glasses, ladders, and maintenance platforms. Pipe connections use flanges for convenient transportation, assembly, and maintenance.

The resistance of activated carbon adsorption towers primarily comes from the pressure loss in the activated carbon adsorption layer and the airflow passing through the housing, generally within the range of hundreds of Pascals, depending on the thickness of the adsorption layer, airflow velocity, and type of activated carbon. Honeycomb activated carbon has lower resistance, cylindrical activated carbon has moderate resistance, and granular activated carbon has relatively higher resistance. When selecting, the thickness of the adsorption layer and airflow velocity should be designed based on the pressure margin of the fan to ensure system air pressure matching. Excessive resistance will increase fan energy consumption, and sufficient air pressure margin should be reserved during selection.

The circulating liquid in the cyclone tower requires regular maintenance to ensure purification efficiency. During operation, the pH and suspended solids concentration of the circulating liquid should be checked regularly. When dust or paint mist sediment accumulates excessively in the circulating liquid, the circulating liquid should be replaced promptly, and the sediment at the bottom of the tower should be cleaned. It is recommended to configure a water replenishment and drainage device for regular effluent discharge and water replenishment. The circulating liquid should be avoided from being discharged arbitrarily and must be discharged after being treated in accordance with environmental protection requirements. Meanwhile, it is necessary to regularly check whether the spray nozzles are blocked and whether the swirl vanes are coated with dust, and perform timely cleaning and maintenance. During winter operation, attention should be paid to anti-freezing. When necessary, insulation measures should be taken or the circulating liquid should be drained regularly.

When installing PP ducts, the following points should be noted: First, the spacing of pipe supports should be reasonable to prevent pipe sagging and deformation; Second, the connection joints should be well-sealed to prevent exhaust gas leakage; Third, the pipes should have a certain slope for convenient condensate drainage; Fourth, avoid contact with sharp objects to prevent scratching the pipe wall; Fifth, for outdoor installation, avoid direct sunlight or take shading measures to delay aging; Sixth, when connecting the duct to the fan or equipment, set up a flexible connection to reduce vibration transmission. After installation, an air leakage test should be conducted to ensure system sealing.

When installing PP elbows, the following points should be noted: First, the elbow specification should match the connected duct to ensure connection size compatibility; Second, during spigot connection, ensure proper insertion and use sealant or seal ring to guarantee sealing; Third, supports should be installed at the bend to prevent concentrated pipe weight at the connection point; Fourth, avoid directly connecting equipment or fans at the elbow; it is recommended to use flexible connections to reduce vibration; Fifth, when multiple elbows are connected in series, maintain reasonable spacing to avoid excessive airflow resistance; Sixth, after installation, perform a leakage test to ensure good sealing at the connection points.

PP Processed Ducts are suitable for applications requiring large diameters, non-standard dimensions, or special-shaped ventilation pipes, such as the main exhaust ducts in large industrial plants, corrosive gas transport pipelines in chemical enterprises, acid-resistant and corrosion-proof ventilation systems in environmental engineering, or on-site scenarios with limited space where customized square or irregular ducts are needed. For standard-sized medium and small-diameter branch pipes, extruded integral-formed PP profiled ducts can be selected. When used together, they balance cost and flexibility. PP Processed Ducts are widely used in industrial, agricultural, chemical, environmental pollution control, and other acid-resistant and corrosion-proof engineering projects.

Regular spray towers rely on a packing layer to increase gas-liquid contact area, suitable for conventional acid-base waste gases and acid mists; the cyclone tower features multiple cyclone blades internally. The first layer sprays counterclockwise, the second layer sprays clockwise, with the two-phase gas colliding in opposite directions, causing dust or paint mist sludge to flow into the bottom of the tower through inertia collision, centrifugal separation, and liquid film adhesion. The third layer is the mist separator with a size transition. The cyclone tower is more suitable for sticky paint mist waste gases and conditions with higher dust content, while the regular packing tower is better for soluble acid-base gases. The cyclone tower has relatively higher resistance, requiring a fan with higher pressure matching during selection.

In the complete exhaust gas treatment system, it is typically used in conjunction with exhaust hood, duct, damper, corrosion-resistant fan, and exhaust stack. A washing or pre-cooling section can be connected before the tower, and after the tower, activated carbon adsorption unit, dry adsorption unit, or regenerative thermal oxidation (RTO) equipment is installed based on the composition of pollutants. The tower itself is equipped with circulating water pumps, chemical dosing system, and piping valves instruments to ensure continuous supply of absorption liquid. When the system contains both acid mist and organic compounds, a combination of spray tower and activated carbon adsorption is often adopted. First, wash the acid and alkali while cooling and removing dust, then let the downstream equipment adsorb organic compounds, with clear division of labor. Xicheng Environmental Protection can provide complete sets including stainless steel spray tower, corrosion-resistant fan, water pump, duct, damper, and downstream adsorption equipment, taking charge of design, manufacturing, installation, and commissioning.

The activated carbon adsorption tower is primarily designed for organic exhaust gases and odors, with limited effectiveness in treating acidic and alkaline exhaust gases. Acidic and alkaline exhaust gases are recommended to be treated by PP spray tower for washing and neutralization. If the exhaust gas contains both organic pollutants and acidic/alkaline components, a combined process of spray tower plus activated carbon adsorption tower can be adopted. First, the spray tower removes acidic/alkaline components, and then the activated carbon tower adsorbs organic pollutants. Using only the activated carbon tower to treat high-concentration acidic/alkaline exhaust gases may cause the activated carbon to fail and lead to equipment corrosion.

The cyclone tower is suitable for installation in industrial settings where paint mist, viscous exhaust gas, or dust-containing exhaust gas is generated, such as spray booths, sanding workshops, polishing production lines, and building material production workshops. The equipment features a vertical structure, occupies minimal space, and can be installed both indoors and outdoors. For locations with limited installation height, options such as horizontal spray towers or non-standard designs with reduced tower height can be considered. The cyclone tower can be paired with PP fans, activated carbon adsorption boxes, and PP ducts to form a complete exhaust gas treatment system.

The tower body of the winding tower adopts a one-piece winding forming process, resulting in higher mechanical strength, better overall integrity, superior corrosion resistance, and anti-leakage performance compared to conventional welded towers. The tower body is aesthetically pleasing and exhibits excellent airtightness. The thickness of the winding tower body can be customized based on actual requirements, ranging from 8 to 70 millimeters, offering enhanced wind resistance performance and longer service life, making it suitable for a wider range of applications. For scenarios involving high airflow and stringent requirements for tower strength and service life, the winding tower is a more reliable choice. Standard towers can also be equipped with spray, packing, and demisting systems. The production cycle of the winding tower is slightly longer than that of conventional welded towers, making it ideal for projects with high quality requirements.