1.25MPA biomass steam boiler manufacturer

Description :

　　The reason why the bag filter of biomass boiler cannot remove dust from the bag is that if the operating resistance of the biomass boiler bag filter is high during use, the boiler will produce smoke and the steam pressure will not increase. The resistance design of small and medium-sized biomass boiler dust collectors has already been determined. If the resistance of the dust collector increases sharply in a short period of time during operation, it indicates that there is a problem with the dust collector. The reasons for high resistance can be divided into two types: occurring immediately after the system is running and occurring after a period of operation. If the design is improper, it can easily cause various phenomena to occur. The second type is caused by operation and maintenance, mainly due to the following reasons.

　　Biomass boilers can burn granular fuel, as well as wood, construction waste templates, sawdust, and sawdust. Their smoke and dust are fine and difficult to capture, so PTFE coated bags are generally used for biomass boiler dust collectors. If the design is reasonable and the filtering air speed is selected appropriately, there should be no problem. If the bag filter of biomass boiler bag filter cannot clear the dust, the following aspects should be checked:

　　1. Poor adjustment of the dust cleaning device

　　Check whether the compressed air of the biomass boiler bag filter contains oil and water, whether the gas supply pipeline is unobstructed, whether the electromagnetic pulse valve is normal, whether the setting of the pulse controller meets the requirements, and whether the jet branch pipe and Venturi pipe are installed correctly.

　　2. Dust filter bag blockage

　　The main reasons for clogging of bag filters in biomass boilers are excessive filtration speed, fine and sticky dust, poor dust cleaning of filter bags, and moisture absorption.

　　If the filtering gas velocity exceeds the design standard of the filter bag, it is highly likely to cause fine dust to get stuck in the fibers of the filter bag, causing blockage of the filter bag. Membrane filter media or a protective powder layer can be used to pre coat the surface of the filter bag. For dust with high viscosity, it is necessary to reduce the filtration gas velocity or increase the pressure of pulse blowing, or use offline pulse cleaning of the filter bag. However, a better method is to increase the filtration area to reduce the filtration gas velocity and extend the service life of the filter bag.

　　The poor dust cleaning of the bag filter bag of biomass boiler bag dust collector mainly includes frequent dust cleaning frequency, long or short dust cleaning time. Excessive frequency of dust cleaning can easily loosen the fiber structure of the dust removal bag, thereby increasing the blockage of the filter bag by fine dust in the exhaust gas. If the cleaning time is too long, the initial powder layer on the surface of the filter bag will be cleaned off together. A short cleaning time can cause unwashed dust to accumulate on the surface of the filter bag, resulting in blockage of the filter bag.

　　The reason for the moisture absorption of the bag filter bag of biomass boiler bag dust collector is that the sealing of the dust collector shell is not tight enough, causing water leakage and entering humid air. The compressed air used for reverse blowing and dust cleaning is not clean (containing oil and water), and the compressed air used for dust cleaning is too cold. To prevent the filter bag from getting damp, in cold regions, the compressed air used for dust cleaning can be heated, insulated, degreased, and dehydrated. After the dust collector stops, continue cleaning for 10-20 minutes. Moisture is the cause of filter bag blockage, and the reason for moisture content is usually due to condensation at low temperatures. Especially when dealing with combustion or high-temperature flue gas, the following methods can be used to prevent it:

　　(1) Avoid turning on when there is high resistance. When there is condensation on the surface of the filter bag, restarting it will cause a large amount of dusty air to make the surface of the filter bag muddy. The inlet of the dust collector should be preheated with dusty air or pre coated with a dust layer.

　　(2) Avoid starting up below dew point. When the dust collector operates below the dew point, uneven distribution of air intake can easily cause localized corrosion of the dust collector housing. Therefore, dust collectors should be avoided from working below the dew point, and insulated devices should be used.

　　(3) Avoid air infiltration. If the flanges, maintenance doors, and other components of the dust collector are not tightly sealed, external air will enter and create a low-temperature zone inside the dust collector, causing condensation and corrosion of the dust collector, resulting in moisture absorption of the filter bag.

　　3. Improper gas distribution: If the inlet gas distribution of the dust collector is uneven, there will be greater resistance when starting up. Therefore, it is necessary to ensure that the intake distribution of the dust collector is uniform.

　　The existing bag filter is not ideal enough in actual operation, and there are still many problems, such as a rapid increase in operating resistance and poor ash discharge. The main reason for this is the uneven airflow organization of the dust collector; Unreasonable dust removal design of filter bags leads to poor regeneration capacity of filter bags; Smoke and dust cover or penetrate into the fiber layer of the filter bag, making it difficult to remove, resulting in a sharp decline in the filtration performance of the filter bag and the occurrence of bag sticking in the short term.

　　The structure of biomass boiler bag filter is improved based on the actual situation of conventional bag filter. By adjusting the internal structure, the flow field distribution of dusty flue gas is changed, which helps to improve the cleaning effect and reduce operating resistance. The structural principle is that the smoke inlet and outlet are arranged on the same side and separated by inclined partitions. The bag chamber consists of four identical compartments, with the lower part connected to the ash hopper. After filtration, the flue gas is controlled by an offline valve to enter the upper box for discharge. The offline valves are closed at intervals in sequence. When one of the compartments is offline, compressed air is injected in reverse to blow off the dust cake collected on the cloth bag and drop it into the ash hopper.

　　By comparing and analyzing the distribution of the flue gas flow field inside the bag filter, it can be concluded that the bag chamber is composed of several compartments based on the characteristics of biomass dust. By taking some filter bags offline and reducing the flue gas flow rate, it can effectively reduce airflow disturbance, facilitate dust shedding and collection, and enhance the regeneration ability of the filter bags. It has increased the filtration area and offline valve equipment, resulting in an increase in cost. However, actual operation has shown significant improvements compared to conventional bag filters, and the cost is lower than switching between dual dust collectors. For the problem of slope accumulation, a vibration damper can be installed on the outer wall of the dust collector hopper depending on the specific situation.

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• Biomass steam boiler