The packing material is the core mass transfer component of the spray tower, and its rational selection directly determines the gas-liquid contact effect, which in turn affects the dust removal, exhaust gas treatment efficiency, and long-term operational stability of the spray tower. This article combines practical experience from overseas industrial sites, refines and analyzes the key points of filling material selection for spray towers, sorts out the key factors affecting dust removal efficiency, and provides concise and practical technical references for on-site operation and maintenance personnel to help optimize the operation effect of spray towers.

1、 Core points for selecting spray tower packing materials (refined and practical)

The selection of fillers should revolve around adaptability to working conditions, mass transfer efficiency, corrosion and temperature resistance, and ease of operation and maintenance. There is no need to pursue high-end models, and the focus should be on meeting actual processing needs. The following are the core selection points.

（1） Core selection criteria

1. Working condition parameters: Priority should be given to matching the gas flow rate, dust concentration, flue gas temperature, and corrosiveness. Conventional fillers can be used for non corrosive working conditions at room temperature, while high-temperature (>80 ℃) and strongly corrosive (acid alkali flue gas) materials should be selected for temperature and corrosion resistance.

2. Dust removal requirements: For fine dust (≤ 10 μ m), fillers with large specific surface area and moderate porosity should be selected to increase the gas-liquid contact time; Coarse dust can be filled with simple and non clogging fillers, balancing efficiency and operation.

3. Operating costs: Taking into account the service life, difficulty of replacement, and energy consumption of the packing material, avoiding cost waste caused by excessive selection, and adapting to the overseas on-site operation and maintenance level.

（2） Common types of fillers and their adaptation scenarios

1. Polypropylene (PP) filler: resistant to weak acids and bases, low cost, suitable for room temperature (≤ 80 ℃), no strong corrosive dust/exhaust gas conditions, such as mechanical processing and woodworking dust control, widely used in overseas small and medium-sized spray towers.

2. Polyvinyl chloride (PVC) filler: It has better acid resistance than PP, slightly lower temperature resistance (≤ 60 ℃), and is suitable for low to medium concentration acidic dust conditions, such as mild acid mist accompanied by dust treatment in the chemical industry.

3. Ceramic filler: Strong temperature and corrosion resistance (temperature resistance>150 ℃), suitable for high temperature, strong acidity and alkalinity, and dust conditions containing sharp particles, such as metallurgy and mining high-temperature flue gas dust removal. It has a long service life but is heavy.

4. Stainless steel packing: resistant to temperature and corrosion, high strength, suitable for high temperature (≤ 200 ℃), strong corrosion, and requiring high packing stability in working conditions such as high-end chemical and pharmaceutical industry dust control, with high cost.

（3） Supplementary selection of packing specifications

The filling specifications are based on specific surface area and porosity as the core reference: conventional dust removal uses 25-50mm specifications, and fine dust treatment uses 16-25mm specifications; If the porosity is too low, it is easy to block, and if it is too high, the gas-liquid contact will not be sufficient. It needs to be matched reasonably according to the size of the tower body.

2、 Key factors affecting the dust removal efficiency of spray towers

The dust removal efficiency is influenced by various factors such as packing, spray system, and working conditions. The core is to optimize the gas-liquid contact effect. The following are the key influencing factors, which are concise, clear, and practical.

（1） Factors related to fillers

1. Packing material and structure: Inconsistent material can easily lead to aging and damage of the packing, while unreasonable structure (small specific surface area, uneven pores) can shorten the gas-liquid contact time and directly reduce dust capture efficiency.

2. Packing quality: Overly dense packing is prone to blockage and increased resistance, while loose packing can cause gas-liquid short circuit, both of which will affect the dust removal effect; It needs to be evenly packed to avoid gaps and uneven stacking.

3. Packing pollution and blockage: Dust adhesion and scaling can reduce the mass transfer performance of the packing, and long-term failure to clean can lead to a continuous decline in dust removal efficiency, requiring regular inspection and cleaning.

（2） Spray system factors

1. Spray pressure and flow rate: Insufficient pressure and low flow rate prevent the spray liquid from evenly covering the surface of the packing, resulting in insufficient gas-liquid contact; Excessive pressure and flow rate can increase energy consumption and easily lead to smoke carrying water.

2. Selection and arrangement of nozzles: nozzle blockage and poor atomization effect can cause the spray liquid to form a droplet shape, which cannot form a uniform liquid film; Uneven nozzle arrangement can result in blind spots where the filling material is not covered by the spray.

3. Spray liquid water quality: If the spray liquid contains too many impurities, it is easy to block the nozzle and contaminate the filler. If the pH value of the water does not meet the standard (such as using alkaline spray liquid to treat acidic dust), it will reduce the dust absorption efficiency.

（3） Working conditions and equipment factors

1. Imported dust concentration and particle size: Excessive concentration can easily cause rapid clogging of the filler, while fine particles (≤ 5 μ m) require efficient fillers and atomization systems to capture.

2. Smoke temperature and flow rate: If the temperature is too high, it will accelerate the evaporation of the spray liquid and reduce the gas-liquid contact effect; A too fast flow rate will shorten the gas-liquid contact time, while a too slow flow rate will reduce the processing capacity. It is necessary to match the tower size reasonably.

3. Tower body sealing and liquid level control: Leakage of the tower body can cause a short circuit in the flue gas, high liquid level can easily cause the flue gas to carry water, and low liquid level cannot guarantee the spraying effect, both of which will affect the dust removal efficiency.

3、 Key considerations (refinement focus)

1. The selection of fillers should prioritize adapting to the working conditions, avoiding a disconnect between "high-end materials" and "actual needs", and reducing operating costs.

2. Regularly clean the packing and nozzle, check the spray pressure and water quality, and avoid the decline of dust removal efficiency due to blockage and aging.

3. When there are fluctuations in working conditions (such as changes in dust concentration and flue gas temperature), it is necessary to adjust the spray parameters in a timely manner to meet the requirements of the working conditions.

4. The replacement of packing materials should use products that are consistent with the original specifications and materials to ensure the gas-liquid contact effect and tower compatibility.

The core of selecting packing materials for spray towers is "working condition adaptation". Reasonable selection of packing materials and specifications, combined with optimized spray systems, can maximize the gas-liquid contact effect; Controlling key factors such as the state of the filling material, spray parameters, and fluctuations in operating conditions can effectively ensure stable dust removal efficiency. The content of this article is in line with the practical needs of overseas industries, providing concise and practical technical references for foreign trade practitioners to help spray towers operate efficiently and stably.