At 6:40 on August 26th, 2008, an explosion occurred in the Guangxi Guangwei Chemical Co., Ltd. organic plant affiliated to Guangxi Vinylon Group Co., Ltd., causing 21 deaths and 59 injuries. There are 18 villages and companies within 3km of the factory. A total of 1,1,500 employees and their families were evacuated. As of September 11, the accident caused direct economic losses of about 75.86 million yuan. It is the most serious chemical accident in the country in the past 10 years.

　　First, the factory profile

　　Guangwei Organic Factory uses polyvinyl acetylene to produce polyvinyl alcohol. The main production units are tank area, synthesis, distillation, polymerization, alcoholysis, recovery, packaging and so on. It was completed and put into production in October 1980. After several technical renovations and expansions, the production capacity of polyvinyl alcohol increased from 10,000 t/a to 30,000 t/a, and the production capacity of vinyl acetate reached 60,000 t/a.

　　The process of producing polyvinyl alcohol by calcium carbide acetylene method is: acetylene from the calcium carbide workshop in the synthesis section and acetic acid, through the catalyst (zinc acetate-activated carbon) to form a reaction liquid → distillation section, separation of vinyl acetate, acetic acid and the like. Vinyl acetate → polymerization section, in the initiator

　　Polyvinyl acetate solution → alcoholysis reaction is formed by the polymerization of arsenic (azobisisobutyronitrile), and reacted with sodium hydroxide to obtain polyvinyl alcohol. Alcohol solution waste liquid → recycling section, treatment.

　　The raw materials, intermediate products, finished products and by-products of the plant mainly include acetylene, acetic acid, vinyl acetate and acetaldehyde, all of which are inflammable and explosive chemicals.

　　Second, the accident passed

　　On the night of August 26, 2008, 49 employees of Guangwei Organic Factory were employed.

　　0:00~6:00, production is normal. The liquid levels of CC-601A, B, C, and E reaction liquid storage tanks were 41, 50, 48, and 46 m3, respectively.

　　At 6:00, the tank area found that the liquid level of the above four reaction liquid storage tanks decreased overall, that is, the dispatch was reported.

　　At 6:40, the first explosion occurred in the western part of the tank area. The ejected material forms a cloud of white mist that diffuses as the wind moves to the north side of the synthesis, distillation section and other areas.

　　At 6:44, there was a strong explosion near the synthetic section and the tank area. Some buildings, equipment and pipelines in the construction, distillation, alcoholysis, polymerization and other sections were damaged by the explosion shock wave. A large number of materials leaked several times and exploded. As a result of the fire, the tanks in the tank area and the Song body pipelines also exploded and burned. Part of the leakage material in the tank area and each section flows into the sewer, causing the plant's sewer, sewage collection tank and total drainage outlet to deflagrate.

　　The explosion caused almost all the tanks to be damaged. The top of the tank of CC-602B was blown to the scale house at 90m on the south side and stumbled.

　　The blast wave also squashed the heads of the nine trucks parked outside the South Gate.

　　In addition, all the pumps in the tank area burned out, the process pipeline was burned 90%, and the cables and electrical switches were completely destroyed.

　　Third, the cause analysis of the accident

　　First, the direct cause

　　Due to the wide range of explosion accidents, large fire area and heavy damage, the on-the-job operation records and key equipment such as major equipment and equipment were burned or damaged. Two on-duty operators in the tank area and other on-duty personnel who may know the situation at the scene were killed. It is difficult to investigate and collect evidence.

　　As of October 20, the accident investigation team has not yet reached an agreement on the direct cause. The focus of the debate? ° ignition source? ±, only a variety of possibilities or assumptions, lack of evidence to support, is inconclusive.

　　Second, indirect reasons

　　1. Five 100m3 storage tanks for storing reaction liquids in CC-601A~E are used in parallel. If an accident occurs, the remaining four will be destroyed. Cause: The amount of leakage is paralyzed, and the consequences of the accident are slim.

　　2. The layout of tanks and tanks and safety facilities do not meet the requirements of current standards and regulations.

　　The tanks in the 1 tank group are 3 rows (current requirements: should not exceed 2 rows)

　　2 material pump is installed in the fire dam (current requirement: should be set outside the fire dam and meet the corresponding fire spacing)

　　3 tank area no flammable gas detection and alarm facilities (current requirements: should be set in the possible leakage of Class A gas (liquid) body)

　　4 There is no isolation valve at the discharge of the firewall (current requirements: sewage and rainwater, isolation valves should be installed at the discharge outlet)

　　3, equipment security management confusion

　　1 During the major repair period from April to May this year, the expansion needs to replace the tank area to the rectification section of 2 reaction liquid pumps. The inlet and outlet pipes are not replaced at the same time. The size head is connected to the original tube. The flow rate is ↑, the head ↑ will bring the flow rate ↑, the static electricity is hazard, the understanding is insufficient, and there is no countermeasure.

　　The foam fire extinguishing system originally installed in the 2 tank area was unusable after 1982 due to lack of maintenance. It was dismantled in 1999.

　　3 tank area operation rules without tank material temperature control requirements, liquid level control indicators are not clear.

　　4 CC-601 series tank exhaust condenser condensate directly sheds into the tank from the 6.65m high nozzle from the bottom plate, causing electrostatic ignition source to impact the liquid surface, lack of understanding!

　　Fourth, the accident lessons

　　1. Hidden troubles investigation and management must be maintained dynamically!

　　2, security facilities must be complete!

　　3, safety production investment, must be willing to use!

　　4. Implement the “Guidance Opinion” and must implement the action!