PP Spray Tower

PP spray tower (polypropylene spray tower) is an environmental protection equipment designed for the treatment of acid and alkali exhaust gas and organic waste gas, with strong corrosion resistance, efficient purification, low-cost operation and maintenance as the core advantages, widely used in chemical, electroplating, electronics, printing, spraying, pharmaceutical and other industries, can effectively treat harmful gases containing acid mist, alkali mist, VOCs (volatile organic compounds) and other harmful gases, is one of the key treatment devices for industrial waste gas to meet the emission standards.

From the perspective of structural design, the PP spray tower adopts a modular vertical or horizontal architecture, and the core is composed of six parts: tower body, spray system, packing layer, gas-liquid separation layer, circulating water tank, and dosing device. The tower body is welded with high-quality polypropylene (PP) plates, usually 8-15mm thick, with acid and alkali resistance, anti-aging and light weight, compared with the traditional carbon steel tower body without anti-corrosion coating, the service life can reach 8-10 years; The spray system is composed of a spray pump, a spray pipe, and a spraying nozzle, which adopts a spiral or fan design, which can atomize the absorbent liquid into fine droplets of 50-100μm, greatly improving the gas-liquid contact area. The packing layer is filled with PP material fillers such as multi-faceted hollow balls and Bauer rings to form a porous adsorption structure and prolong the contact time between the exhaust gas and the absorbent liquid. The gas-liquid separation layer is equipped with a baffle or mist eliminator to intercept the droplets carried in the exhaust gas and avoid secondary pollution. The circulating water tank stores the absorbent solution (such as sodium hydroxide solution for acid mist and sulfuric acid solution for alkali mist), and automatically adjusts the pH value with the dosing device to ensure stable absorption efficiency.

Its working principle follows the process of "gas-liquid reverse contact-absorption purification-gas-liquid separation": dusty exhaust gas enters from the air inlet at the bottom of the tower and flows evenly upwards through the airflow distribution plate; At the same time, the absorbent liquid in the circulating water tank is transported to the spray pipe through the spray pump, and sprayed from top to bottom after atomization by the nozzle. In the packing layer, the atomized liquid droplets are in full contact with the exhaust gas, and the harmful components in the exhaust gas (such as H₂SO₄ and HCl in acid mist, benzene and toluene in organic waste gas) neutralize and react with the absorbent liquid or dissolve and adsorp. The purified exhaust gas passes upwards through the gas-liquid separation layer, and after removing the carried droplets, it is discharged from the air outlet on the top of the tower. The waste liquid that has absorbed harmful components is returned to the circulating water tank, which can be recycled after dosing and adjusting, and discharged into the subsequent wastewater treatment system when the waste liquid concentration reaches the set value.

Compared with traditional carbon steel spray towers or FRP spray towers, PP spray towers have significant advantages: they have stronger corrosion resistance, can withstand acid-alkali environments with pH values of 1-14, and do not require regular maintenance of anti-corrosion coatings; The weight is lighter, the density of PP material is only 1/8 of carbon steel, and the equipment installation does not require large lifting equipment, reducing the construction cost. The purification efficiency is high, and the combination of the atomization nozzle and the packing layer can purify more than 90% of acid and alkali exhaust gas, and the purification efficiency of low and medium concentration VOCs can reach 70%-85%. The operation and maintenance cost is low, the PP material is not easy to scale and clog, the failure rate of spray pumps, nozzles and other components is low, and the absorbent can be recycled to reduce the consumption of consumables.

The equipment usually handles air flow of 500-50000m³/h, and the tower size can be flexibly customized according to the exhaust gas emissions, and can be treated with a single tower or multiple towers in series. However, it should be noted when using it: when treating high-temperature exhaust gas (>80°C), a cooling device should be installed at the front end to avoid the deformation of the PP tower; When treating high-concentration organic waste gas, it is necessary to use deep treatment equipment such as activated carbon adsorption boxes to ensure that the discharge meets the standards; Regularly check the pH value of the circulating water tank and the blockage of the packing layer to avoid affecting the purification effect.

In general, PP spray towers have become the preferred equipment for small and medium-scale industrial waste gas treatment due to their corrosion resistance, high efficiency and easy maintenance, and play an important role in reducing the cost of environmental protection treatment and reducing air pollution.