The wet electric demister is a highly efficient flue gas purification device, which is widely used in industrial production to remove droplets and particulate matter from flue gas. Its working principle is based on the charging of droplets and their collection under the action of an electric field. However, the operating conditions such as flue gas temperature and flow rate have an important influence on the droplet charging and collection efficiency of the wet electric demister. A deep understanding of these influencing mechanisms is of great significance for optimizing the operating parameters of the wet electric demister and improving its performance.
Changes in flue gas temperature can affect the droplet charging process. On the one hand, the increase in temperature will intensify the thermal motion of gas molecules, increase the degree of gas ionization, and produce more ions. These ions collide with droplets and adhere to the surface of droplets, making the droplets easier to charge. On the other hand, high temperature will accelerate the evaporation of water on the surface of droplets and reduce the droplet size. Smaller droplets have a larger specific surface area and can adsorb more ions, thereby improving the charging efficiency. However, if the temperature is too high, it may cause the gas breakdown voltage in the electric field to decrease, causing the electric field to be unstable, which is not conducive to the droplet charging.
The flue gas temperature also has a significant effect on the droplet collection efficiency. When the temperature rises, the viscosity of the gas increases, and the resistance to the movement of the droplets in the electric field increases. This slows down the migration speed of the droplets in the electric field and prolongs the collection time. At the same time, high temperature will reduce the gas density in the electric field, increase the mobility of ions, and cause changes in the distribution of electric field strength. Uneven electric field strength will cause the movement trajectory of the droplets to deviate and reduce the collection efficiency. In addition, excessively high temperatures may also cause the performance of the plates and insulating components of the wet electric demister to deteriorate, affecting the normal operation of the equipment and further reducing the droplet collection efficiency.
The flue gas flow rate mainly interferes with the charging of droplets by affecting the residence time of the droplets in the electric field. When the flue gas flow rate is low, the droplets stay in the electric field for a longer time, have more opportunities to collide with ions and charge, and have a better charging effect. When the flue gas flow rate is too high, the droplets stay in the electric field for too short a time, and are taken out of the electric field before they are fully charged, resulting in a decrease in charging efficiency. In addition, high-speed airflow will also intensify the collision between droplets, which may cause the droplets to break or merge, change the particle size distribution of the droplets, and thus affect the charging effect.
The effect of flue gas flow rate on droplet collection efficiency is relatively complex. On the one hand, if the flow rate is too high, the droplets will move too fast in the electric field, exceeding the ability of the electric field force to act on the droplets, making it difficult for the droplets to be collected by the electrode plate and reducing the collection efficiency. On the other hand, appropriately increasing the flue gas flow rate can enhance the turbulence of the gas, making the droplets more evenly distributed in the electric field, which is conducive to improving the collection efficiency. However, if the flow rate is too high and the turbulence is too strong, the movement trajectory of the droplets in the electric field will become disordered, increasing the possibility of droplet escape, and reducing the collection efficiency. In addition, the flue gas flow rate will also affect the airflow distribution inside the wet electric demister. Uneven airflow distribution will lead to a weakening of the local electric field strength and reduce the droplet collection efficiency.
In actual operation, the flue gas temperature and flow rate often change at the same time, and there is an interaction between them. For example, when the flue gas temperature increases, in order to ensure the processing capacity of the equipment, the flue gas flow rate may be increased accordingly. However, this simultaneous change of temperature and flow rate will have a more complex effect on droplet charging and collection efficiency. The combination of high temperature and high flow rate may reduce the efficiency of droplet charging, and the collection efficiency is also greatly affected. Therefore, when optimizing the operating parameters of the wet electric demister, it is necessary to comprehensively consider the relationship between temperature and flow rate to find the best operating conditions to improve the droplet charging and collection efficiency.
Flue gas temperature and flow rate are important operating conditions that affect the charging and collection efficiency of wet electric demister droplets. Temperature affects the charging and collection efficiency by affecting factors such as gas ionization, droplet particle size and electric field characteristics, while flow rate mainly interferes with the charging and collection process by changing the residence time and motion state of droplets in the electric field. The combined effect of the two makes the operation of the wet electric demister more complicated. In order to improve the performance of the wet electric demister, it is necessary to reasonably control the flue gas temperature and flow rate according to the specific flue gas conditions, optimize the equipment operating parameters, so as to achieve efficient droplet charging and collection, and achieve good flue gas purification effect.
