Thermal power plant accident case
1. Accident profile
On February 25, 2016, a thermal power plant in datang occurred a hot wind burning accident in the hot air tunnel at the entrance of no. 1 boiler C coal grinder during the maintenance operation, resulting in a major production safety accident that killed three people.
Datang a thermal power plant equipment management department of the preparation of no. 1 boiler C coal grinder internal maintenance program, after approval to implement.
The work leader of C coal mill maintenance working group zhang xx and the point inspector entered C coal mill for inspection and found that C coal mill centering bracket was opened for welding. They decided to deal with the welding of welding joint in the hot primary air duct and the root packing fault of sealing cover of hot primary air conditioning baffle shaft found in the previous operation.
Monitor li mou as C coal mill maintenance work site in charge of the maintenance work task assigned to the powder class, sent wang mou, tan mou to participate in the C coal mill entrance hot a wind path repair welding operation.
In the afternoon, li xx was engaged in the repair welding of a hot air passage at the entrance of C coal mill.
In the afternoon, li held a class meeting and arranged the work in the afternoon: the technician of the powder production team contacted the operator of the power generation management department and arranged li to debug the inlet heat air conditioning baffle of C coal mill. The repairman of the powder production team cleaned the waste insulation cotton above the heat primary air duct and cooperated with the debugging of the heat primary air damper. Wang xx, the repairman of the powder class, is the guardian of limited space operation. Li mou checks and accepts the welding position in the hot primary air duct.
Li arrived at C coal mill maintenance site, at this time, 6.9 meters platform construction scaffolding has been set up, li mou, wang mou, tan mou is entering the coal mill hot air channel for operation, wang mou outside the hot air channel monitoring.
Li opened the cabinet door of the control cabinet with a screwdriver in the local control cabinet of the 6.9m platform with the hot primary air driven plug door, switched the "far control/near control" switch in the control cabinet to the "near control" position, and pressed the solenoid valve starting switch. There was no response after the first press, and no response after the second press.
Li mou in 6.9 meters platform railing to a hot air duct on the inspector shouted, asked the adjustment baffle moved? The repairman kicked the adjusting baffle link crank with his foot and waved his hand to show that it was not moving.
Li also opened the manual valve of air source at the inlet of C coal mill with the warning sign of "no operation for human work". At this time, the door of the first air flow is opened, and the hot air at 309℃ is injected into the first air passage of the inlet of C coal mill with a pressure of 6kPa, and li mou, wang mou and tan mou are involved in the bottom of the bracket of the inlet of C coal mill.
Rescue workers enter no. 1 boiler C coal mill inlet to heat the primary air duct, rescue trapped personnel. But all were confirmed dead.
Direct cause of the accident
In the maintenance process, the inspector li a serious violation of the operation. In does not have equipment under the condition of the related conditions, check the device name identification, to open air solenoid valve plug door and there is "no operation someone work" placard air valve manually, the original coal mill inlet hot atmosphere in a closed C moving door open, the temperature is 309 ℃, pressure is 6 kpa coal mill inlet air injection C heat within a duct, lead to accidents.
In today's developed industry, although a lot of mechanization instead of human hands, but some important links are unable to do machinery. Work can continue to carry out the security, the establishment of orderly workflow is essential. First - rate workflow to work, reduce safety hazards, ensure the quality of work.