Safety Preparations Before Maintenance
Energy Isolation: Strictly implement the Lockout-Tagout (LOTO) system, cut off the power supplies of the induced draft fan, unloader and air compressor, hang "No
Closing the Switch" warning signs, isolate the material conveying pipelines with blind plates, and release the residual pressure of the compressed air system to 0MPa.
Ventilation and Testing: Open all manholes and access doors, perform forced ventilation with an explosion-proof axial flow fan for no less than 30 minutes, test to
ensure the oxygen content is between 19.5% and 23.5% and the combustible gas concentration is less than 10% LEL, and conduct re-tests and record the results every
2 hours.
Site Clearance: Clear all combustibles within a 10-meter radius around the dust collector, equip dry powder fire extinguishers and fire sand boxes, and keep the access
passages in the work area unobstructed.
Personnel and Protection: All operators must hold corresponding special operation certificates, and be equipped with KN95 or higher-grade dust masks, anti-static work
clothes, safety helmets, and double-hook safety belts. Assign 2 full-time supervisors for confined space operations, and equip them with two-way radios and
emergency rescue tripods.
Safety Control During Maintenance
Filter Bag Replacement Operation: Use explosion-proof tools to remove the perforated plate bolts; striking that may generate sparks is strictly prohibited. Use nylon
ropes to tie and hoist the filter bags to avoid friction with metal components. It is strictly forbidden to step on the perforated plate to prevent deformation and ash
leakage.
Ash Hopper Ash Cleaning Operation: When the thickness of accumulated ash in the ash hopper reaches 0.5m or more, clean it with a vacuum dust collection
equipment, and directly striking the ash hopper wall is prohibited. Ensure the temperature of the ash hopper does not exceed 40℃ during operation to prevent the
accumulated ash from collapsing and causing personal injury.
Electrical System Maintenance: Test to ensure the insulation resistance of the pulse valve and lifting valve coils is no less than 0.5MΩ, check that the grounding
resistance of the PLC control system does not exceed 4Ω, clean the dust inside the control cabinet, and hot-plugging modules under live conditions is strictly
prohibited.
Structural Component Maintenance: Use an ultrasonic thickness gauge to test that the thickness of the wall panel is not less than 80% of the designed value.
Adopt cold working process to repair the deformed perforated plate, and open fire operations are prohibited. Ensure the height of the maintenance platform
guardrail is no less than 1.2m to prevent falls from heights.
Emergency Management, Acceptance and Restoration
Emergency Support: Equip positive pressure air respirators, first-aid kits and stretchers on site, formulate special response plans for incidents such as dust explosions
and poisoning/suffocation, and organize 1 emergency drill for confined space operations every quarter.
Joint Acceptance: Conduct joint acceptance jointly by the safety, equipment and production departments, count all tools to confirm no sundries are left inside the tank
body, check that the sealing strips of the manholes are in good condition, and the tightening torque of bolts meets the design requirements.
System Restoration: Carry out no-load trial operation first, monitor that the pressure difference between the inlet and outlet does not exceed 1500Pa, confirm that the
pulse valves act synchronously, and put the system into formal production after 72 hours of continuous operation and re-test to verify that the emission concentration
meets the standards.
