PP spray tower is a common industrial waste gas purification equipment. It is mainly used to treat acidic waste gas, alkaline waste gas, dust and some waste gas with pungent odor generated during the production process. The equipment purifies harmful components in the exhaust gas through spray absorption, filler contact and gas-liquid separation, so that the treated gas meets the corresponding emission requirements.

1. Main application scenarios of PP spray tower

PP spray tower is usually used for industrial dust removal, acid and alkali waste gas treatment and harmful gas pretreatment. It can be installed in chemical production equipment, electroplating equipment, pickling equipment, etching equipment, laboratory exhaust system, spray pre-treatment equipment and other production lines that generate corrosive waste gas.

For working conditions with higher exhaust gas concentration, more complex components or higher treatment requirements, multi-stage spraying, double towers in series or combination with activated carbon adsorption towers can be used according to the actual situation to improve the overall purification effect.

2. Main components of PP spray tower

PP spray tower is mainly composed of tower body, circulating water tank, circulating water pump, spray pipeline, nozzle, packing layer, demister layer, air inlet, air outlet, maintenance port and drainage device.

1. Spray system: Spray the absorbing liquid evenly into mist or raindrops to fully contact the exhaust gas with the absorbing liquid.

2. Filling layer: disperses air flow and liquid flow, increases air-liquid contact area, and improves absorption and neutralization efficiency.

3. Circulating water tank and water pump: store and circulate the absorption liquid so that the spray system can continue to operate.

4. Demist layer: separates the liquid droplets entrained in the gas and reduces the discharge of water mist with the air flow.

3. Principle of Acidic Waste Gas Treatment

When PP spray tower treats acidic waste gas, the gas-liquid countercurrent contact method is usually used. The acid waste gas enters from the lower part of the spray tower, and the circulating water pump transports the alkaline absorption liquid in the water tank to the upper nozzle of the tower body, and sprays it into mist or raindrops.

The exhaust gas flows from bottom to top, and the absorption liquid flows from top to bottom. The two are in full contact in the packing layer. The filler can disperse the air flow and water flow, increase the contact area, and fully neutralize the acidic waste gas and alkaline absorption liquid, thus reducing the concentration of harmful components in the waste gas.

The gas after spray absorption and filler treatment will then pass through the demister layer to remove entrained droplets, and finally be discharged from the air outlet.

IV. System configuration suggestions

1. When the exhaust gas concentration is high, two PP spray towers can be used for treatment in series.

2. When the exhaust gas contains obvious odor or organic components, a PP activated carbon adsorption tower can be added at the back end of the spray tower.

3. The absorption liquid should be replenished with chemicals in time according to the composition of the waste gas. When dealing with acidic waste gas, the pH value of the circulating liquid can usually be controlled at around 7 to 9, and the specific range should be determined according to the actual working conditions.

4. Systems with higher requirements for chemical control can be equipped with automatic dosing devices and pH online monitoring devices.

5. The fan should be arranged in an induced draft type so that the fan is installed at the rear end of the purification equipment to reduce the impact of corrosive exhaust gas on the fan impeller, bearings and other components.

5. Performance characteristics of PP materials

PP materials have low water absorption. The water absorption rate after soaking in water for 14 hours is about 0.01%. It also has good molding properties and is suitable for processing and manufacturing spray towers, scrubbers, air ducts and related accessories.

PP material has high crystallinity, regular structure, good strength, hardness and elasticity, and good bending fatigue resistance. It is suitable for manufacturing exhaust gas treatment equipment that requires long-term operation and maintenance.

In terms of thermal properties, the melting point of PP material is about 164 to 170°C, and it has good heat resistance. In the absence of obvious external force, a certain structural stability can still be maintained at higher temperatures, but brittleness may occur in low-temperature environments. Therefore, the operating temperature of the equipment should be reasonably determined based on the material grade and actual working conditions.

In terms of chemical stability, PP materials have good tolerance to a variety of acids, alkalis and chemical reagents, but concentrated sulfuric acid, concentrated nitric acid and some organic solvents may still corrode, soften or swell the material. Therefore, before selecting equipment materials, the exhaust gas composition, liquid concentration and operating temperature should be confirmed.

6. Equipment Usage Characteristics

PP spray tower has the characteristics of relatively simple structure, acid and alkali resistance, corrosion resistance, low operating resistance, easy operation and maintenance, etc., and is suitable for use in a variety of industrial waste gas purification systems. Equipment specifications, spray levels, filler height, circulating water volume and chemical type should be designed according to the treatment air volume, exhaust gas concentration and emission requirements.