Prize-winning Quiz on Coal Chemical Engineering Knowledge 5

The management requirements for open flames should include: obtaining a safety permit for working with open flames, and the relevant departments carrying out necessary inspections and implementing appropriate measures； Before starting any work that involves fire, ensure that fire prevention and extinguishing facilities are in place, and remove any flammable materials from the surrounding area. Firework operations carried out inside towers and tanks also require the completion of relevant procedures ； When using an open flame, safety must be ensured, with a dedicated person assigned to supervise it, and fire extinguishing equipment should be available nearby. Personnel performing hot work must strictly follow safety procedures, and in the event of a fire or explosion, they must promptly organize firefighting efforts ； After starting a fire, the area must be thoroughly cleared of all sources of ignition before leaving the site. Leaks, emissions, drips, and spills are major factors contributing to low yields. Strict control of these issues can help save energy and reduce consumption, minimize environmental pollution, and lessen wear and tear on equipment.

The management requirements for open flames should include: obtaining a safety permit for working with open flames, and the relevant departments carrying out necessary inspections and implementing appropriate measures； When using an open flame, safety must be ensured, with a dedicated person assigned to supervise it, and fire extinguishing equipment should be available nearby. Personnel performing hot work must strictly follow safety operating procedures ； After starting a fire, the area must be thoroughly cleaned before leaving. Strict control of leaks, spills, evaporation, and drips can help save energy and reduce consumption, as well as minimize environmental pollution and equipment wear and tear.

The management requirements for open flames should include: obtaining a safety permit for working with open flames, and the relevant departments carrying out necessary inspections and implementing appropriate measures； When using an open flame, safety must be ensured, with a dedicated person assigned to supervise it, and fire extinguishing equipment should be available nearby. Personnel performing hot work must strictly follow safety operating procedures ； After starting a fire, the area must be thoroughly cleaned before leaving it. The hazards of leaks, spills, and other such issues include energy waste, reduced equipment lifespan, disruption to normal production processes, and potential safety risks.

The management requirements for open flames should include: obtaining a safety permit for working with open flames, and the relevant departments carrying out necessary inspections and implementing appropriate measures； When using an open flame, safety must be ensured, with a dedicated person assigned to supervise it, and fire extinguishing equipment should be available nearby. Personnel performing hot work must strictly follow safety operating procedures ； After starting a fire, the area must be thoroughly cleaned before leaving. Strict control of leaks, spills, and other forms of waste can reduce consumption and lower costs, while also preventing fires and explosions caused by the leakage of flammable and explosive substances. .

Leakage, spillage, dripping, and seepage refer to leaks of liquid or gaseous chemical raw materials/intermediates/products that occur during storage, production, or transportation, due to corrosion of containers or pipelines, poor sealing, or excessive pressure or flow rates. Generally, small amounts are called drops or leaks, while large amounts are called seepage or leakage. The purpose of controlling leaks is: 1. To meet the requirements of safe operation management; 2. For environmental protection; 3. To save energy; 4. To ensure people’s normal living conditions

October 27th of last year was a disastrous day for the refinery of Daqing Petrochemical Branch Company; on that day, a fire and an explosion took the lives of 7 employees forever. It seems as though that happened just yesterday, and now their anniversary is approaching again. Before that day arrives, and in order to serve as a reminder to chemical enterprises, this article has been written. Given the special nature of chemical enterprises, small chemical plants across the country experience fires and explosions from time to time. So what are the causes of such accidents? How can it be prevented? Fire accidents occur widely. Fire and explosion accidents in chemical enterprises occur not only across the country but also in various workshops within a single factory. From process operations, equipment and pipelines, production maintenance to design and manufacturing, violations in command, improper operations, and management gaps can all lead to fires. The losses from fire and explosion accidents are quite severe. Fire and explosion accidents in chemical enterprises have resulted in the damage of individual units, as well as the destruction of the entire plant’s production facilities. More cases involve production disruptions due to the damage of individual pieces of equipment or critical machinery. Among these severe consequences are also the loss of lives among workers and managers. After such accidents, not only does it take doubled efforts to restore production at the plant, but they also contribute to instability in society. The severe consequences of fire and explosion accidents keep the safety situation in chemical enterprises in a passive state. Causes of fires: The reasons for the frequent fire accidents in chemical enterprises can be summarized as follows: Leakage of flammable gases. Since flammable gases, when released into the air, can form explosive mixtures, their leakage easily leads to fire and explosion incidents. Such accidents are generally caused by factors such as chaotic piping in production equipment, substandard materials for sealing or improper maintenance, inadequate operation and maintenance, application of external force without first releasing pressure during maintenance, and failure to follow the operating procedures when conducting routine inspections or starting/stopping operations. Therefore, it is necessary to manage such situations in accordance with the maintenance procedures stipulated by the former Ministry of Chemical Industry, the standards for leak-free factories, and other relevant regulations on equipment and power management. For any leaks that have occurred, they should be detected and eliminated promptly; for those that cannot be eliminated immediately, preventive measures must be taken to prevent them from spreading or causing disasters. Negative pressure in the system leads to a mixture of air and flammable gases. Such accidents mostly occur in positions related to gas transportation or gas compression; they are even more dangerous when they happen during the pressurization process, as in an explosive mixture the oxygen content increases, and moreover the explosion range widens after pressurization, increasing the likelihood of accidents. Excessive oxygen levels occur during system operation. While such high oxygen levels can appear in various areas, the root causes lie primarily in the gas generation unit; they are usually caused by operational errors, equipment defects, violations of safety procedures, interruptions in the supply of oil or gas, or failures in safety alarm systems. Excessive oxygen levels may also arise in areas such as desulfurization, conversion, and compression units, beyond the gas generation unit, and this situation warrants special attention. System air leakage: The causes of fires resulting from system air leakage can generally be divided into two situations; one is when high pressure mixes with low pressure, leading to an overpressure explosion ； Another type is a chemical explosion resulting from the mixing of air with flammable gases. The former case is mostly caused by operational errors, as well as the absence of safety accessories at low pressures or the failure of such accessories. Such as an explosion in the high-pressure ammonia synthesis tank connected to a low-pressure tank, or an explosion in the high-pressure ammonia synthesis system connected to a low-pressure regeneration system, etc. The latter case is mostly caused by errors in removing or installing blind plates, such as using valves in place of blind plates or improper operations. If welding is carried out on a device that contains air, and since the system isn’t isolated using blind flanges, combustible gases may leak in through valves, or someone might accidentally open a valve that was closed, allowing combustible gases to enter the device where welding is taking place. There, these gases mix with air to form an explosive mixture, resulting in an explosion. Illegal welding involves the following: carrying out welding work without obtaining a welding permit and without having the necessary safety knowledge, as well as performing welding work privately ； Although a hot work permit was applied for, the purging was not thorough enough or the sampling method was incorrect, resulting in erroneous analysis results ； Fire safety measures were not properly considered ； The safety conditions at the site where welding work is being carried out were not thoroughly checked ； The hot work system is not thoroughly isolated from other systems ； Privately altering safety measures or changing the timing of hot work without authorization ； Hot work without displacement or hot work without maintaining positive pressure. Such accidents are a major focus of chemical fire and explosion incidents. Given the high technical complexity of hot work and the stringent management requirements associated with it, the safety and technology department should exercise strict control to prevent accidents. Fire prevention measures: Although there are many cases of fires and explosions in chemical enterprises, and considerable experience and lessons have been gained as well as a good understanding of the areas prone to such incidents, there are numerous factors that can lead to combustion and explosions during the production process, and these factors cover a wide range of aspects. In particular, some of the sources of fire that cause combustion and explosions are not easy to identify. Therefore, preventing fires and explosions is a complex and meticulous task. The focus of fire and explosion prevention should be on controlling and eliminating combustible materials, oxidizing agents, and ignition sources, ensuring that these three do not come into interaction at the same time. At the same time, it is required to take strict and reliable measures technically and administratively in order to prevent the expansion of the accident situation. Control and eliminate hazardous factors. In chemical enterprises, there are many opportunities for technical upgrades and minor reforms carried out as part of major overhauls. During the design changes, advanced process technologies and reliable fire and explosion prevention measures should be employed, along with safe process parameters and appropriate piping systems. Strengthen equipment management; a major cause of fire accidents is defects in production facilities. Equipment in good condition has a long operational life, requires minimal maintenance, has few potential hazards, and thus experiences a low incidence of fires and explosions. Units that manage their equipment well also have better production conditions. With the development of chemical enterprises, there is a need to increase automation not only to save energy and reduce consumption, improve quality, and boost labor productivity thereby enhancing economic efficiency, but also to improve safety through greater automation. Thanks to the increased level of automation, overheating, overpressure, and overloading are avoided, thereby ensuring stable and long-term operation of the production equipment and preventing accidents. The use of interlocked protection devices can enhance the safety of the system; in the event of any abnormal conditions, these interlocked protections will automatically shut down or take action, thereby not only preventing accidents from occurring but also stopping their spread. Of course, when using safety interlock devices, maintenance should be strengthened first, with regular inspections to ensure their sensitivity and reliability ； At the same time, the sense of responsibility for safety work should not be reduced; one must not become complacent just because of the presence of safety devices. Special attention should be paid to protecting those components that are particularly dangerous. Strengthen the management of ignition sources and hazardous materials. A significant cause of furnace explosions is the lack of proper control over ignition sources. The common types of ignition sources in chemical enterprises include open flames ； Sparks generated by friction and impact ； Electrical sparks and static sparks ； Other sources of fire (referring to materials that can catch fire on contact with hot surfaces, cigarette butts, motor vehicles, etc.). Hazardous materials prone to fire and explosion include the following: explosive substances, oxidizers, flammable and oxidizing gases, flammable and oxidizing liquids, flammable solids, self-igniting substances, and substances that burn when in contact with water. According to the properties of various hazardous materials, they are stored and kept in separate categories as required. During storage, it is essential to control three key stages: the acceptance stage upon entry, the storage stage while in inventory, and the re-inspection stage upon exit. Explosion-proof pressure relief measures: Commonly used explosion-proof pressure relief devices include safety valves, explosion-proof membranes, explosion-proof doors, vent valves, and drain valves, which are primarily used to prevent physical overpressure explosions. Safety valves should be calibrated regularly, and when selecting them, attention should be paid to the operating pressure and pressure release speed. The function of explosion-proof membranes and doors is primarily to prevent the high pressures generated during chemical explosions; when selecting such components, calculations must be carried out to choose appropriate parts. Relief valves and drain valves are used as pressure relief mechanisms in emergency situations, but they require manual operation; therefore, it is essential to ensure they are easy to use. Adhering to a people-oriented approach, to prevent fires in chemical enterprises it is also necessary to establish a fully equipped dedicated fire fighting team. Therefore, it is important to select and train commanders who are highly conscientious and of high quality, possess a certain level of professional knowledge, have an understanding of petrochemical processes, and are able to handle potential fire hazards and accidents properly. In accordance with standardized requirements, a strict daily routine is enforced. Based on the actual conditions of our enterprise, we must focus on technical and tactical training, pursue the path of building a highly skilled force, and derive combat effectiveness from training. Vigorously carry out training at duty posts and initiatives to encourage everyone to strive to become a \"technical expert\" in their respective roles. Improve the professional competence of fire service officers and staff to meet the requirements of the new situation for fire protection work.