“The direct cause of the explosion at the Yima Gasification Plant identified as a \"sand blast\"

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“The direct cause of the explosion at the Yima Gasification Plant identified / Author/Source: Coal Chemical Industry / Date: 2019-07-29 / Views: 107. At around 17:45 on July 19, 2019, an explosion occurred in the Air Separation Unit C at the Yima Gasification Plant of Henan Gas Group in Sanmenxia City, Henan Province (hereinafter referred to as the Yima Gasification Plant), resulting in 15 deaths and 16 serious injuries. Based on preliminary investigation and analysis, the direct cause of the accident was the failure to address promptly a leak in the cold box of the air separation unit, which led to a \"sand explosion\" (when there is a leak in the cold box of an air separation unit, large amounts of low-temperature liquid accumulate within the perlite insulation material; when this low-temperature liquid evaporates rapidly, the shell of the cold box is forced to expand and burst, causing gas along with large quantities of perlite to be ejected). This in turn resulted in the collapse of the cold box, leading to the rupture of a liquid oxygen storage tank with a capacity of 500 cubic meters located nearby. A large amount of liquid oxygen escaped rapidly, and flammable materials in the vicinity exploded or caught fire under the influence of the liquid oxygen or oxygen-rich environment, resulting in numerous casualties among the people around. The specific cause of the accident is under further investigation. Since the beginning of this year, the national chemical industry has witnessed three major accidents: the \"3·21\" incident in Xiangshui, Jiangsu; the \"4·15\" incident in Jinan, Shandong; and the \"7·19\" incident in Sanmenxia, Henan. These accidents resulted in heavy casualties and severe consequences, drawing widespread attention from society. The \"7·19\" accident in Sanmenxia, Henan, revealed a lack of safety awareness and risk awareness among the enterprises involved, as well as poor capabilities in identifying risks. There was inadequate response to device leaks, and operations continued despite existing problems; significant safety gaps existed in the management of equipment and production processes. The accident also exposed serious issues such as an unreasonable design layout of the factory and insufficient attention paid to the safe operation of supporting facilities like air separation units. Following the accident, senior leaders of the State Council attached great importance to it and issued important directives, calling for full efforts to carry out search and rescue operations as well as treat the injured. They ordered that the causes of the accident be determined as soon as possible, and that strict action be taken in accordance with laws and regulations. At the same time, it was necessary to learn deeply from this accident, give top priority to the safety supervision of hazardous chemical enterprises, further identify related safety hazards, and prevent the occurrence of serious accidents. To thoroughly learn from the lessons of this accident, draw broader conclusions from it, strengthen risk identification and control, effectively fulfill the enterprise’s primary responsibilities for safe production, further improve safety measures in the handling of hazardous chemicals, resolutely prevent and curb serious accidents, and fully protect the lives and property of the people, the following requirements are hereby set forth: 1. It is strictly prohibited to operate equipment while it is in a faulty condition; special inspections should be conducted on air separation units. This accident occurred because leaks in the air separation unit at Yima Gasification Plant were not addressed in a timely manner, resulting in the continued operation of the unit in a faulty state. On June 26, 2019, the Purification Branch of Yima Gasification Plant detected an increase in oxygen content within the insulation layer of the cold box of Unit C of the air separation unit; it was determined that there was a slight oxygen leak, but insufficient attention was paid to this issue, as it was believed that monitoring the operation would be sufficient ； On July 12, cracks appeared on the outer surface of the cold box, and the leakage increased further. Due to factors such as the substandard condition of the backup air separation system equipment, the company continued to operate despite these issues, failing to take measures to shut down the plant for maintenance in a timely manner, until an explosion occurred on July 19. All relevant enterprises must earnestly learn from the lessons of these accidents, fully recognize the significant safety risks associated with operating chemical production facilities in a faulty condition, properly balance profitability and safety, adopt the mindset that \"hidden dangers are accidents,\" ensure that any such dangers are eliminated as soon as they are detected, and resolutely prevent facilities and equipment from being operated in a faulty state. Emergency management departments at all local levels must carry out strict law-enforcement inspections; whenever serious hazards such as the operation of equipment in a faulty condition are detected, they must order immediate corrective action and impose penalties in accordance with the law, ordering shutdowns where necessary ； It is necessary to urge enterprises involved in air separation units within the jurisdiction to carry out inspections for potential risks and hazards. The key points of such inspections should include whether there are leaks in the cryogenic tanks, whether the overall layout of the air separation units is reasonable, whether organic substances in the air at the inlet of the air compressors are properly controlled, whether the hydrocarbon content in the liquid oxygen system is regularly monitored with accurate data, and whether the liquid oxygen storage tanks are safe. Any issues or hazards identified during these inspections must be addressed immediately; those facilities that do not meet safety requirements should cease operations right away. II. Strengthen professional management of equipment to ensure its proper operation. Yima Gasification Plant was once an enterprise recognized for its safe production practices, but due to shortcomings in comprehensive safety management, as well as a lack of awareness regarding safety and risks related to equipment and production processes, professional management of such assets declined, which became a significant factor contributing to accidents. Chemical production processes are complex and operate under harsh conditions; the materials used are often flammable, explosive, toxic, and harmful. Moreover, operating conditions such as high temperatures, high pressures, and low temperatures place strict demands on the condition of the equipment. In daily production, process fluctuations, improper operations, incorrect use, and inadequate maintenance can all lead to equipment failure, resulting in material leaks and accidents. Strengthening the management of equipment integrity is the foundation for safe chemical production. Relevant enterprises must attach great importance to professional equipment management, optimize equipment design and selection from the outset, and improve the level of intrinsic safety. It is necessary to select equipment and facilities with mature technology and good performance, thoroughly understand safety-related information such as the design materials and operating parameters of the equipment, and establish strict technical procedures for equipment inspection and maintenance. It is necessary to increase the frequency of inspections at key areas, ensure that backup equipment is in good condition, carry out preventive maintenance thoroughly, and eliminate potential problems at an early stage. III. Strengthening comprehensive management of safety in chemical processes. Chemical processes involve various specialties such as process engineering, equipment, instrumentation, and electrical systems, as well as complex utility systems. Strengthening the safety management of these processes is an effective way to prevent and control chemical accidents from a professional perspective. It constitutes an essential foundation for enterprises to eliminate potential hazards promptly, prevent accidents, and establish long-term mechanisms for safe production. Relevant enterprises should integrate all elements of chemical process safety management into their daily enterprise management systems and treat them as key components, ensuring that each element is properly implemented. They should conduct regular assessments in accordance with the requirements of chemical process safety management, identify weak points, and make continuous improvements to enhance the scientificity and systematicness of their enterprise safety management. It is necessary to strengthen production organization and management, properly handle the relationship between safety and production, and always adhere to the safety production policy of \"safety first, prevention first, and comprehensive management\" in order to effectively prevent the occurrence of serious and major accidents. IV. Conduct targeted warning education for key executives of enterprises. Emergency management departments in various regions should organize a warning education campaign by the end of August 2019, aimed at raising the legal awareness, risk awareness, and understanding of lessons learned from accidents among the key executives of chemical and hazardous materials enterprises. Central enterprise branches as well as provincial-owned enterprises shall have such campaigns organized by the provincial emergency management departments, while other chemical and hazardous materials enterprises shall have them organized by the municipal emergency management departments. After completing these warning education campaigns, the provincial and municipal emergency management departments should sign commitment letters with the key executives of relevant enterprises, urging them to focus on carrying out safety risk assessments and control measures to ensure safe production. V. Earnestly ensure safe production in the chemical and hazardous chemicals sector during this hot season. We are currently in a hot season, with frequent extreme weather conditions such as scorching heat, thunderstorms, and typhoons, which have an adverse impact on the safe production in these industries and make it a period prone to accidents. Relevant enterprises must earnestly draw lessons from the chemical and hazardous materials accidents that have occurred during hot seasons in recent years, conduct thorough risk assessments, formulate scientific preventive measures, focus on inspecting key areas, critical locations, and essential positions, and implement responsibilities and control measures for managing major hazardous sources of hazardous materials. Management protocols must be tightened for any work involving open flames or operations in confined spaces within areas where hazardous materials are stored. Emergency management departments at all levels should focus on key areas and key enterprises, urging them to strengthen duty coverage, implement job responsibilities, and carry out regular inspections; any issues detected must be addressed promptly. At the same time, attention should also be paid to non-key areas and non-primary production facilities, in order to prevent serious accidents resulting from problems that are not anticipated, monitored, or addressed, thus creating a stable safety environment for the 70th anniversary of the founding of the People’s Republic of China. Please promptly disseminate this notice to the local emergency management departments at all levels within your jurisdiction, as well as the relevant enterprises. General Office of the Ministry of Emergency Management, July 25, 2019