Case Studies of Boiler Operation Accidents--7
Thread Content
Incident involving casualties at Zunyi Power Plant: At 0:20 on May 9, 2001, the slag removal machine of Unit 8 at Zunyi Power Plant stopped operating due to a chain breakage issue, and emergency repairs were carried out. Around 0:35, the operator closed all the sealing panels on the left side of the slag removal machine for Unit 8; one panel on the right side could not be closed due to mechanical jamming, and the operator informed the shift supervisor, waiting for maintenance personnel to arrive at the site for repairs； At around 4:30, the maintenance staff repaired the slag extractor chain and requested a test run. At around 5:40, the trial run was successful, but no dust could be removed. Upon inspection, it was determined that the chain had come loose from beneath the chain guide pulley at the corner on the starboard side; therefore, it was necessary to reverse the direction of operation and drain the water from the slag remover. The shift supervisor did not agree to reverse the operation; instead, he instructed the operators to wash the chain tensioning pulley with high-pressure water. Before releasing water, the furnace operator was instructed to use an oil gun to maintain a stable flame. After flushing out the chain guide pulley, the maintenance worker failed to reset the chain by prying it into place, and decided to resort to cutting the chain in order to reset it. At around 6:40, a large piece of slag suddenly collapsed inside the furnace, creating a gap at the joint of the shut-off door panels. Red ash sprayed out through this gap, burning the 4 people who were preparing for emergency repairs on the platform next to the slag skimmer. Of these 4 injured individuals, 3 died in the hospital, while 1 was seriously injured.
Analysis of the accident cause: 1. Safety regulations were not followed. When dealing with slag skimmer failures, operators are required to follow relevant regulations by adding oil to maintain stable combustion, keeping a negative pressure, and closing the sealing baffles of the shut-off doors. 2. No effective emergency measures were taken. Due to their insufficient technical and professional skills, the persons in charge of the work lack the ability to identify and address defects. They are also unaware of the unsafe working conditions they are in, as well as the fact that the longer such conditions persist, the greater the potential hazards; as a result, no effective emergency measures were taken to prevent accidents from occurring. The above are the main causes of this personal injury.
Accident summary: The construction supervisor, upon arriving at the site, failed to identify the equipment defects accurately; his technical skills were inadequate, and he worked for an excessively long time, up to 5 hours. When the maintenance team requested to drain the water from the seal water tank, the permit issuer failed to comply with the regulation stating that the task of draining the water should be completed within a short time, and also agreed to carry out the work without implementing additional safety measures; no safety measures were taken during the execution of the work permit. 1. Conduct regular safety and technical training for personnel at all levels to improve the level of safety and technical protection. 2. Strengthen education on employees’ self-protection awareness, and ensure that emergency measures are in place in situations with high risks ； Please have experienced workers and veterans provide guidance based on their experience, in order to increase the knowledge and experience of young employees. 3. Regularly conduct safety awareness education for employees to strengthen their safety consciousness, ensuring adherence to the principles of \"not harming oneself, not harming others, and not being harmed by others\" as well as the importance of \"never forgetting safety and cherishing life.\" Persist in opposing inertial illegal activities. 4. Personnel at all levels must pay attention to their personal safety, earnestly fulfill their safety responsibilities, thoroughly understand the safety measures and requirements for various tasks, and strictly abide by all relevant regulations and procedures.
At 00:20 on May 9, 2001, the slag removal machine of Unit 8 at Zunyi Power Plant stopped operating due to a chain breakage issue, and emergency repairs were carried out. Around 00:35, the operator closed all the sealing baffles on the A side of the slag removal machine for Unit 8; one baffle on the B side could not be closed due to mechanical jamming, and the operator reported this to the shift supervisor while waiting for maintenance personnel to arrive on site for repairs； At around 4:30, the maintenance staff repaired the chain of the slag skimmer