The lack of proper treatment of abnormal TDI conditions in Dahua, Cangzhou

At 13:28 on May 11, 2007, an explosion occurred in the nitrification plant of the TDI workshop of China National Chemical Corporation's Ganzhou Dahua TDI Co., Ltd., resulting in 5 deaths and 80 injuries, including 14 serious injuries. The power supply system in the plant area was seriously damaged. Thousands of people in nearby villages were evacuated and transferred.
After preliminary investigation of the cause of the accident, the State Administration of Work Safety analyzed that the immediate cause of the explosion was the abnormality of the treatment system in the mononitration system. The acid replacement caused excess nitric acid in the system. After the toluene was fed, the nitrification of the nitrification system occurred. The reaction produces dinitrotoluene that should have been produced in the dinitration system and trinitrotoluene (TNT) that should not be produced. Because there is no cooling function in a nitrating static separator, a large amount of heat can not be removed by the nitrification reaction. After the temperature of the static separator rises, the normal separation effect is lost, and the organic phase and the inorganic phase mix. The mixture flows into the nitrotoluene storage tank and the spent acid storage tank, and the reaction is continued here, resulting in a rapid rise in the temperature of the nitration static separator and a nitrotoluene storage tank, and the nitration of the nitration product occurs at high temperatures.
The explosion accident also exposed management problems. TDI production workshops, technical management confusion, strict control of process parameters, abnormal operating conditions did not strictly enforce the technical operating procedures; in the case of a long time in an abnormal state of the production device, the process parameters obviously abnormal situation, failed to take correct The technical measures that led to the accident. In addition, personnel technical training is not enough, technical personnel can not make a comprehensive analysis of the abnormal phenomenon of the device and make a correct judgment; the operator has no experience in handling abnormal conditions.