To resolve excessive resistance of the dust collector, you can carry out step-by-step operations in the sequence of "first inspect the ash cleaning system, then address
filter bag clogging, and finally optimize the system operating conditions" to quickly bring the pressure difference back to the designed normal range.
Troubleshooting and Optimization of Dust Cleaning Systems
This is the most common cause of excessive resistance. Prioritizing its inspection can quickly resolve 80% of minor resistance issues:
Calibrate core dust cleaning parameters: Set the pulse width to 0.1-0.2s, and the dust cleaning interval to 30-60s under normal working conditions; when the pressure
difference exceeds 80% of the designed value, automatically shorten the interval to 15-30s to prevent dust from accumulating into a dense ash layer on the filter bag
surface.
Inspect the air source and injection components: Ensure the compressed air pressure is stably maintained at 0.5-0.7MPa, install an oil-water separator and a refrigerated
dryer to guarantee the dew point of compressed air ≤ -40℃, so as to avoid bag clogging caused by moisture and oil; check each pulse valve one by one, replace faulty
parts with damaged diaphragms or stuck spools, to ensure powerful injection.
Calibrate the injection alignment accuracy: Adjust the injection pipe with a laser aligner to ensure the parallelism deviation from the tube sheet is ≤ 1mm, so that the
high-pressure airflow is vertically aligned with the center of the filter bag, preventing incomplete local dust cleaning caused by offset blowing.
Targeted Disposal of Filter Bag Clogging
Filter bag pasting and dust embedding are the core reasons for persistently high resistance. Carry out classified treatment according to the clogging degree:
Minor clogging: Adopt the combined dust cleaning method of offline pulse back-blowing and mechanical rapping, and manually blow off the floating dust on the filter
bag surface to restore the basic air permeability.
Moderate clogging: Select compatible chemical cleaning according to the filter bag material to dissolve the viscous dust in the fiber pores, and reuse the filter bag after
the air permeability is tested to meet the standard.
Severe clogging: When the filter bag is hardened and the fiber pores are completely blocked, replace the whole set directly. For working conditions with high dust
concentration, prioritise membrane-coated filter bags to reduce the permanent pore blockage caused by fine dust penetrating into the fibers.
Simultaneously inspect the filter bag cages: Replace rusted, deformed or burr-equipped filter bag cages to ensure the filter bags are fully stretched without extrusion,
avoiding local dust accumulation that drives up the resistance.
System Flow Field and Operating Condition Optimization
If the resistance is still too high after eliminating the first two types of problems, rectification needs to be carried out at the system level:
Balance the internal flow field: Install deflectors at the air inlet to eliminate local eddy currents and high-speed air passing zones, ensure the filtration load of filter bags
in each chamber is uniform, and prevent the excessively high resistance of a single chamber from raising the overall pressure difference.
Clean dead corners of dust accumulation: Thoroughly clear the hardened dust in the ash hopper, install a level gauge to control the accumulated material in the ash
hopper not exceeding 2/3 of the height, and equip with air cannons to prevent dust bridging, so as to avoid secondary dust raising from the bottom accumulated dust
that repeatedly adheres to the filter bags.
Strictly control temperature and humidity to prevent condensation: Stabilize the operating temperature of the box body to be 15-20℃ higher than the flue gas dew
point, block the air leakage points of access doors and pipeline flanges, prevent low-temperature cold air from seeping in and causing water vapor condensation, and
fundamentally eliminate the hardening and pasting of wet dust on filter bags.
Match the filtration wind speed: If the filtration velocity far exceeds the design standard, fine dust will be stuck into the filter bag fibers. The filtration wind speed can
be reduced by increasing the filtration area, so as to reduce the risk of bag clogging from the root cause.
Long-term Operation and Maintenance Prevention Mechanism
Establish a classified pressure difference control ledger, set three-level thresholds of normal, warning and exceeding the standard, and track the change trend of
pressure difference in real time; conduct filter bag resistance tests every quarter, detect the response time of pulse valves every half year, and deal with hidden dangers
such as slight bag pasting and abnormal injection in advance, so as to avoid the long-term accumulated resistance exceeding the standard.
