Boiler dust collector renovation

With the further improvement of environmental standards and the further reduction of smoke and dust emission concentration, most electrostatic precipitators in coal-fired power plants are facing renovation problems. In recent years, our factory has been engaged in the development of electrostatic precipitator maintenance and renovation industry. We have successfully transformed electrostatic precipitators for coal-fired boilers in many self owned power plants such as Shijiazhuang, Shandong, Shanxi, Shaanxi, and Inner Mongolia into electric bag composite precipitators. The electric bag composite precipitators can meet emission standards, and the equipment is in good operating condition, receiving high praise from users. Our factory has technical personnel to provide you with reasonable design solutions, reducing the user's investment to a low level.

Economic benefits comparison between electrostatic precipitator and bag filter

The working pressure loss of the electrostatic precipitator system is low, generally less than 250Pa, and high-pressure policies are applied within the temperature range. However, changes in boiler coal combustion, operating conditions, and load all affect the efficiency of the precipitator, leading to unstable smoke emission concentration, especially when the boiler burns low sulfur coal and high specific electrical resistance coal, the dust removal efficiency decreases significantly; The concentration of smoke and dust emitted by bag filters is low. For low sulfur coal and high specific resistance coal, it is technically difficult for electrostatic precipitators to achieve a smoke and dust emission concentration of less than 50mg/m3, requiring significant investment. Although bag filters are not affected by changes in coal quality, smoke composition, or ash resistance. However, the loss of system working pressure is large, and although the changes in smoke concentration and particle size have a small impact on dust removal efficiency, they directly or indirectly affect the service life of the filter bag. To achieve an economic service life of more than 3 years for the filter bag, high requirements are placed on the stability of flue gas parameters and the maintenance and management of the dust collector. So far, there have been no industrial applications of bag filters in coal-fired power plants in China that exceed 28000 hours (the service life of filter bags).

Advantages of electric bag composite dust collector

A considerable portion of the coal used in China's thermal power plants is high in ash content, especially in circulating fluidized bed boilers that burn coal gangue. The concentration of dust in the flue gas is high, and the use of pure bag filters for dust removal is difficult and has high resistance. Frequent dust removal seriously affects the service life of filter bags, and even some equipment has excessive resistance, which affects the load of the unit. An electric field is arranged at the front of the bag filter to collect 80% -85% of the dust. The remaining 15% -20% of the dust is fully charged in the electrostatic precipitator and enters the bag filter unit. Due to the low dust load and electrostatic effect, the dust layer on the surface of the dust filter bag is loose, the working resistance is reduced, the cleaning effect and frequency are reduced, and the service life of the filter bag is extended. Therefore, for coal-fired boilers with high smoke and dust concentration, the development of electric bag combined dust collectors can solve the problem of "meeting standards" for existing electrostatic precipitators.

In recent years, the technology of converting electrostatic precipitators into bag filters has generally been to retain the individual electric fields of the electrostatic precipitator as primary electrostatic precipitators while keeping the original electrostatic precipitator shell unchanged. Then, the three electric fields of the electrostatic precipitator are removed, and the space of these two electric fields is used to arrange the bag filter. In this way, without moving the shell, the space of the original two and three electric fields is divided into compartments, and the flower plate holes and filter bags are arranged in a matrix of vertical and horizontal columns. This arrangement makes reasonable use of the square box space and avoids the idle space at the four corners of the box caused by the concentric circle arrangement. The center of the filter bag is separated from the lifting space of the dusty gas, while avoiding collisions that may occur due to the shaking of the filter bag.

The bag filter adopts the popular low-pressure pulse blowing method for dust cleaning. The dust cleaning system consists of a stabilizing air bag, a pulse valve, a blowing pipe, and a drainage nozzle. It has the advantages of good dust cleaning effect, low equipment resistance, small maintenance workload, and low dust cleaning pressure. It avoids the occurrence of high failure rates caused by the easy damage of rotating spray bearings and the difficulty in lubricating them, and avoids the problem of high equipment resistance due to insufficient dust cleaning during rotation. Our bag filter uses a pressure difference controller to provide feedback signals. As the filtering process progresses, when the surface area of the dust removal bag reaches a certain level of dust, the resistance of the dust collector will rise to a value (which can be set, generally weighing 1500Pa). The electromagnetic pulse valve of the bag filter is opened in sequence to blow, and compressed gas is induced to enter the bag in a very short time sequence through various pulse valves and nozzles on the blowing pipe, inducing several times the amount of injected clean smoke into the bag, forming an air wave, causing the bag to rapidly expand and vibrate from the bag mouth to the bottom, causing the bag to shake and forming a reverse blowing airflow from inside to outside, resulting in a reverse cleaning effect, shaking off the dust on the bag and achieving the purpose of cleaning.

Shengjing Environmental Protection Company has rich experience in electric bag conversion, and the structure of the electric bag composite dust collector is reasonably matched. It fully utilizes the original structure of the electrostatic precipitator, retains the shell, ash hopper, and ash conveying and discharging system, and maximizes the use of the existing structure and accessory equipment of the electrostatic precipitator. Therefore, the renovation work is small, the construction period is short, and the cost is low. Our company's mission is to achieve dust removal, low operating resistance, long service life of filter bags, and meet strict environmental protection requirements.

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