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On June 14, 2001, an injury accident involving a conveyor belt occurred at a coking plant in Taiyuan, Shanxi Province, resulting in the death of one operator. I. Incident Overview: At 15:00 on June 14, Hao, the operator at Position 3 of the belt conveyor in the plant’s coal preparation workshop, entered the conveyor to carry out pre-shift inspections and cleanups from the control room. Around 15:10, Liu, the person responsible for feeding coal, noticed that there was a break in the coal flow on Belt 3; he went to the coal receiving hopper to check the situation. After feeding coal, he found that the conveyor belt was misaligned. Attempts to correct this issue on the spot were unsuccessful, so he headed towards the tail wheel of Belt 3. About 5–6 meters away from the tail wheel, he saw a broken shovel handle on the north side of the tail wheel; Hao himself was not visible. Realizing the seriousness of the situation, he immediately stopped the conveyor and informed the relevant personnel. Upon arriving at the scene, the relevant personnel found Hao lying face down under the tail wheel of conveyor belt No. 3, with severe head injuries; he was immediately taken to the hospital, but died despite efforts to save him. Upon on-site inspection, it was found that the belt had shifted 150 mm to the south. There was no coal accumulation on the northern side of the tail wheel, while there was about 10 mm of coal accumulation on the southern side. The shovel was broken into 3 pieces on the north side of the tail wheel; the head was facing slightly eastward and southward, while the feet were facing slightly westward and northward. The body was lying beneath the tail wheel of the belt conveyor, with blood spots found about 200 mm away from the head. Gloves and a hat had fallen under the belt. Based on the on-site investigation, it is inferred that while Hao was cleaning the coal stuck to the end of the conveyor belt, his shovel became entangled in the moving belt and was then flung by it; it hit a hard object near the end of the belt, breaking. Hao failed to release the shovel quickly, and was pushed forward by inertia, resulting in his head hitting the hard object and causing his death. II. Analysis of the accident cause: After the accident occurred, the local authorities formed an investigation team to analyze it. It was determined that: (1) Operator Hao handled the coal stuck to the rear wheel of the machine while it was still in operation, violating the factory’s rule that \"it is not allowed to clean, repair, or address faults on machines that are running.\" This was the direct cause of the accident ； (2) The conveyor belt lacked an emergency stop device, and there were no protective railings at the tail end of the machine, which were important causes of this accident ； (3) The factory’s inadequate safety management, insufficient safety training for employees, and incomplete safety protection facilities were among the causes of this accident.

A gas leak and fire occurred due to faulty valves in the coking workshop of xx Coking Plant; on the morning of December 17, 1986, workers in that workshop were cleaning the gas pipes. Heating was stopped at 10 o’clock for scheduled maintenance. After completing the regular maintenance tasks, we went to repair the gas valve on the coke side of Boiler No. 2. At 10 o’clock, shift workers Xu XX and Wang XX went to close the main valve. There are about 20 centimeters left before it can no longer be closed. After the two of them came down, Shao XX and Wang XX went to close the main valve again, fearing it might not be sealed properly, until it could no longer be closed. At 10:05, a power outage occurred suddenly across the entire plant, and power was restored at 12:25. After the wind returned, all members of the ironwork team went to repair the gas valve on the coke side of Furnace No. 2. At 13:15, while removing the valve screws, a large amount of gas leaked out, causing an unpleasant odor. The director asked Xu to go and call the safety officer at the branch factory. Shortly after Xu left, there was a loud explosion, and the entire switching room was set alight; 9 people suffered burns (minor injuries). Cause of the accident: The gas valve could not be closed properly due to the absence of a blind flange ； The weather is sleety; pressure and temperature are low, and gas disperses more slowly indoors ； Lack of preventive measures and on-site supervision personnel.

Fire and explosion hazard analysis in the coking workshop of a coking plant. The coking workshop consists of coke ovens, a quenching (wet method) system, as well as screening and storage systems for coke. This system involves flammable and explosive substances such as coke, coke oven gas, blast furnace gas, tar, crude benzene, and ammonia. Therefore, if there are welding defects, poor sealing, incomplete safety accessories, or improper material selection in the numerous valves, pipes, and equipment present in this system – such as rising pipes, gas collection pipes, exhaust valve devices, and coke oven heating equipment – leaks may occur, posing a risk of fire and explosion. In the coke oven basement, or when installing gas isolation valves, if a large amount of gas escapes and comes into contact with a source of fire, there is a risk of fires and explosions ； When working with gas, the use of iron tools, the presence of open flames in the vicinity, or exposed high-temperature steam pipes pose a risk of fire and explosion accidents ； When gas pipelines are shut down for maintenance, deposits such as naphthalene or iron sulfide within the pipes pose a risk of spontaneous ignition ； Leakages that occur when working on gas equipment, starting work without thoroughly clearing the gas from the equipment during maintenance shutdowns and without having fire suppression facilities ready, as well as lightning strikes or the accumulation of iron sulfide at the coke oven gas discharge points, all pose a risk of causing fires and explosions. In coking production and maintenance, if there are equipment defects or inadequate measures to cut off gas, there is a risk of fire and explosion. For example, on July 29, 1981, during maintenance of the main gas return valve for Furnace No. 1 in one of the coking plants, the valve used to shut off the gas was not tight, allowing some gas to leak. When maintenance work began, gas escaped and caused a fire, which damaged the power distribution circuits of the coke oven and led to a shutdown of operations. Furthermore, if the vent pipes in a coking system are not designed in accordance with regulatory requirements, there is a risk of explosive mixtures forming when these vents release gas. On October 3, 1985, a coking plant used an unused 45-meter-high chimney as an automatic gas vent, which led to the formation of an explosive gas mixture inside the chimney. The head of the equipment department led three people to remove waste steam pipes at a distance of five meters from the chimney; during the welding and cutting operations, a gas explosion occurred, causing half of the 45-meter-high chimney to collapse. This incident resulted in 4 deaths and 5 serious injuries. Gas is introduced into the furnace combustion chamber before the temperature reaches the ignition point, resulting in the formation of an explosive mixture inside the furnace; an explosion will occur when ignition takes place ； In a furnace with forced air supply, if the fan is not turned on, gas will enter the air supply ducts; this can lead to an explosion when ignition occurs ； When supplying gas for ignition, if the operator mistakenly thinks that turning the gas valve open means closing it and thus allows gas to flow in, there is a risk of explosion upon ignition ； During the first ignition of the coke oven, the gas supplied did not catch fire; without any treatment, the remaining gas was used for the second attempt at ignition, posing a risk of explosion ； If the blower of the coke oven loses power suddenly, the gas cannot burn completely; some of the gas leaks from the burner into the air ducts, posing a risk of explosion ； For gas pipelines ready for operation, if they are not separated from existing gas pipelines using blind flanges, gas can leak into the new pipelines through the gate valves. If no sampling and analysis are conducted, an explosion can occur during welding work. The falling of red coke can lead to fire accidents. Since the coke pusher, the coke stopper, and the coke quencher are located on different sides of the coke oven, the drivers cannot see each other’s vehicles. If coordination is poor or mistakes occur, accidents resulting from the falling of red coke can happen if the coke stopper fails to position itself correctly relative to the guide grates, or if the coke quencher does not arrive in time to push the coke away. Push the red coke onto the coke side platform, where it falls on the quenching lane. As a result, several tons, or even over twenty tons of red coke ended up on the ground. Fallen red coke can cause fire accidents; more importantly, if red coke is pushed into the driver’s cab of a coke car or a quenching vehicle, it can kill or injure the driver. If such a vehicle is located in front of the furnace, it may be pushed off the furnace bed, resulting in serious accidents that lead to vehicle destruction and loss of life. Accidents in which coke cars were pushed off coke ovens occurred successively at the Linsteel Coking Plant in July 1983, the Xinjiang Iron and Steel Company’s Coking Plant in November 1986, the Jigang Coking Plant in September 1983, the Meishan Coking Plant in November 1976, and the Xingang Coking Plant in 1981 ； In 1987, a coke car at the Wuxi Coking Plant was pushed over ； In March 1990, the coke stopping track at the Ningxia Coking Plant was designed. On September 8, 1971, in chamber No. 44 of furnace No. 16 in the coking workshop of a steel plant, it was difficult to push out the coke due to deformation of the furnace wall, and the coke could not be pushed out despite multiple attempts. It was shift change time, and the coke car driver received instructions to retract the guide rack and stop pushing the coke, but forgot to inform the coke pusher. After the coke stopper car withdrew from the coke guide grid, the pusher car pushed the red coke out; the coke stopper car tilted as a result. Seeing the raging fire approaching him, the driver of the coke stopper car quickly jumped toward the side of the furnace. At that moment, the coke stopper car derailed and its body rebounded, crushing the driver between the furnace columns where he was burned to death.

News from September 4, 2007: At around 3 p.m. on September 1, a large fire broke out in the oil guiding workshop of a coking plant in Liuzhou, Guangxi. The dispatch and command center of the Liuzhou detachment quickly mobilized the entire Liubei Fire Brigade to go and handle the situation. After more than an hour of strenuous efforts to put out the fire, it was successfully extinguished. Thanks to rapid response and effective command, no explosions occurred in the adjacent oil tanks during the fire fighting, allowing several large storage tanks and liquefied gas pipelines in the vicinity to be successfully protected; the fire did not result in any casualties. At 15:35 on the 1st, the dispatch and command center of the Liuzhou Fire Brigade received a report that a large leak had occurred in a heat transfer oil tank in the oil guiding workshop of a coking plant located at No. 117, Beique Road, Liubei District, resulting in a massive fire. Upon receiving the alarm, the command center immediately dispatched the Liubei squadron with all its resources to the scene to carry out firefighting efforts. At 15:40, the officers and soldiers of Liubei Squadron arrived at the fire scene. From a distance, it was possible to see that one of the heat transfer oil tanks in the oil handling facility had been completely engulfed by flames. The toxic fumes released by the burning heat transfer oil filled the entire factory area. Heat transfer oil is a type of light fuel; next to the tank on fire, there was another tank containing 30 tons of benzene, which was at risk of being affected by the spreading flames. Several tanks connected to the tank on fire were marked with the warning “Beware of explosion.” If not extinguished promptly, this could lead to severe chain reactions involving explosions, with consequences that are hard to imagine. While conducting a fire assessment, the commander of the Liubei squadron ordered the technical personnel on site to immediately close the valves and cut off the supply of materials, thereby stopping the production process in that area. Then, the commander promptly issued the combat orders; all combatants put on air respirators, and the vehicle number one, parked to the north of the oil tank, used its onboard water cannon to extinguish the fire at the tank ； Vehicle number 2 was parked to the northeast, from where two water guns were used to cool the adjacent oil tanks and liquefied gas pipelines, in order to prevent explosions that could result from heat radiation ； Vehicles 3 and 4 will stop to the northeast, access the fire hydrant, and use two 80-meter hoses to supply water to Vehicle 1 ； The dedicated duty team and the plant security staff are to carry out inspections and set up barriers to strictly control access and eliminate all sources of fire. After some time of efforts to put out the fire, it was successfully contained within a certain area. At this point, the commander learned from the on-site technicians that after the valves were closed, there was still about 20 tons of heat transfer oil in the tank. It would take a long time to burn all of this heat transfer oil completely, and the surrounding storage tanks might be punctured or explode due to prolonged exposure to heat radiation. The commander promptly changed the combat strategy and ordered an immediate full-scale attack. Vehicle No. 2 deployed a foam gun as well as a water gun; under the cover of the water cannon team, they launched an assault on the bottom of the tank. 20 minutes later, the raging fire was finally completely extinguished. The fire caused no casualties. Currently, the cause of the accident and the economic losses are under investigation.

A coking plant underwent maintenance on January 15, 2005, and the coke ovens were stopped from being heated at 5:30 p.m. At 6:27, an explosion occurred in the coke oven flue. The access hatch at the lower part of the large chimney was blown open, and some bricks on the floor of the flue basement were dislodged. The suction flap of the separate flue was damaged. The fire viewing cover on the top of the furnace was blown off. Accident analysis: 1. When heating was stopped, the gas heating was halted using a switch, but the blast furnace gas valve in the basement was not closed. 2. The high pressure of the blast furnace gas caused it to flow directly from the exhaust valve into the flue, reaching the explosive limit of the gas.

Regarding the disconnection of the motor car attached to the coke quenching vehicle: Course of events: On the morning shift of November 16, 2006, at 5:30, the coke quenching vehicle went to chamber No. 10 of furnace No. 1 to remove the coke there. Wang Hongji, the driver of the coke quenching vehicle, drove it to the coke quenching tower to carry out the quenching process. After completing the quenching at 5:35, he set off to leave the tower and head to the coke drying area; however, the connection between the coke quenching vehicle and the motor car broke, resulting in the rupture of three flexible connectors for air pipes at that connection point. This caused delays: furnace No. 1, chamber No. 15, was delayed by 2 hours and 20 minutes, chamber No. 20 by 30 minutes; furnace No. 2, chamber No. 33 by 2 hours and 30 minutes, chamber No. 38 by 2 hours, and chamber No. 43 by 30 minutes. The issue was resolved at 8:10, and coke removal resumed normally. II. Reasons: 1. The coupling of the newly manufactured coke quenching vehicle does not match that of the electric locomotive; the height difference between their center lines is 30 MM. 2. It is caused by the absence of shock absorber springs on the coupler head of the coking car, resulting in direct impact. 3. The locking device of the coupling between the coking car and the motor car failed to function properly, and no locking effect was achieved. 4. The operator failed to conduct timely inspections and failed to detect it in a timely manner. III. Measures: 1. Provide a complete set of spare parts for the coupling hooks connecting the coking car to the locomotive, to carry out replacement. 2. Install a safety protection chain between the coke quenching vehicle and the motor car to prevent disengagement. 3. Strengthen the inspection of equipment at workstations and conduct regular patrols, addressing any existing or identified issues promptly.

Report on an Incident Caused by an Empty Coal Tower, Affecting Coking Operations I. Incident Overview: From 18:00 on December 22, 2004, to 2:10 in the early morning of the following day, an incident occurred in the first coking workshop due to an empty coal tower, which affected coking operations. The coal blending worker in Section B of Coking Workshop 1 started feeding coal in accordance with standard procedures after taking over the shift. Around 18:00, he noticed that it was becoming increasingly difficult to feed coal into Main Coke Bin No. 1, so he called the section leader. The section leader then inquired by phone about the amount of coal stored in Main Coke Bin No. 1 with a large inclination angle, and was informed that there was still around 300 tons left, thus ruling out the possibility that the low amount of coal was the cause of the difficulty in feeding coal in. At 18:10, two personnel from other positions were sent to assist in handling the situation; methods such as using air cannons, drills, and hammers were attempted, but with little effect – the amount of coal entering the warehouse remained less than the amount exiting it. By 23:50, the remaining coal in the coal tower was exhausted. This resulted in the loss of focus in 3 holes; a total of 108 tons of coal were fed during the 4th shift in Section B. At 24:00, the shift change took place at Section D; the section leader summoned 3 people to organize the loading of coal. However, the same method was still used, and the coal loading continued to be intermittent. At 1:04, the supervisor received a call from the dispatch control center and went from the control room to the coal mixing site. At 2:25, the deputy supervisor received a call and rushed there from home. Based on an analysis of the actual conditions on site, it was determined that the cause of the blockage in the silo was the freezing and accumulation of coal blocks. The best solution was heating, and it was decided to use iron rods wrapped in cotton yarn dipped in gasoline, which would then be lit and inserted into the silo to dry and heat it up. After 20 minutes of baking, as the temperature inside the chamber gradually increased, the frozen coal blocks began to fall one after another. At 4:10, coal feeding has gradually returned to normal and can now meet the production needs. The problem has been solved. A total of 220 tons of coal were loaded during the zero-o’clock shift at Ding Duan. In this incident of an empty coal tower, it resulted in the failure to complete the production schedule for 3 coke ovens in Workshop 1 for December 22; on December 23, another 10 ovens could not produce coke due to insufficient coking time. The production order and coke pushing coefficient are disrupted. II. Accident analysis: After the accident occurred, the workshop and relevant departments organized personnel to conduct an analysis, and two reasons were identified: 1. The temperature at the work site was too low, causing the coal to freeze against the walls of the storage area, resulting in the accumulation of coal piles. 2. The operators’ methods for dealing with faults are not flexible, and the problems are not resolved at their root. III. Rectification measures: 1. Install a coke furnace in the coal blending room to increase the temperature inside. 2. The downtime of the conveyor belt during shift handover should not be too long to prevent the warehouse walls from freezing. 3. Workshop leaders and section chiefs must keep track of the daily coal supply at all times, and take preventive measures promptly based on the amount of coal supplied.

Reply to 6# Yun Shu: Are you from the coking operation area of Anling Steel?

Thank you all for sharing; it’s all very educational

At around 3 p.m. on September 14, 1989, a trial production was underway in the smelting workshop of a metallurgical plant in this city; suddenly, the filter bag No. 1 came loose. The management immediately sent a mechanic named Zhou to go to the bottom of the filter unit to carry out repairs. During that period, the No. 3 air intake and exhaust device located next to the dust collector suddenly \"tripped\" and stopped operating, causing the large amount of carbon monoxide gas generated by the coke added to the furnace to remain around the No. 1 dust collector via the air supply system. Zhou, who was performing maintenance at the bottom of the dust collector, immediately suffered poisoning and collapsed. Seeing that Zhou had gone in for maintenance and hadn’t come out for a long time, the other two assembly workers went down to the bottom of the dust collector to check on him, only to also fall ill from poisoning and pass out one after another. After the accident, the factory immediately sent the three people to the hospital for treatment. The hospital diagnosed Zhou as suffering from severe acute carbon monoxide poisoning, while the other two assembly workers had mild acute carbon monoxide poisoning. Fortunately, thanks to prompt rescue, all three survived. Comment: The smelting workshop of this factory is a new facility that is still in the trial production and debugging phase; it is normal for there to be some issues with production techniques and equipment. Therefore, enterprises should pay more attention to establishing occupational health and safety systems and formulating operational procedures for occupational health and safety. During the trial production and debugging phase, strengthen on-site supervision and management, install carbon monoxide alarm devices, and ensure that workers wear personal protective equipment while working; this way, accidents can be avoided.