【Accident Case Analysis】Handling and Prevention of Scalding Accidents in Petrochemical Enterprises

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During the petrochemical production process, the presence of large amounts of high-temperature media and high-temperature equipment surfaces, along with various chemical agents, makes burns very likely to occur. In the petrochemical production process, fires, explosions, poisoning, and asphyxiation are generally regarded as the types of accidents that require focused control. Since the consequences of burns are often not very severe – in most cases resulting only in minor, localized burns that can heal on their own without special treatment – they do not tend to attract much attention. However, the likelihood of such accidents is high, and some of the injuries can be severe; or they may become serious due to lack of treatment or improper treatment, resulting in wounds that fail to heal properly. Once healed, severe scars may form, affecting appearance and function, and even posing a threat to life. Therefore, high attention should also be paid to burns. What is a burn injury? A burn injury refers to injuries caused by flames, hot objects, chemical burns (injuries inside or outside the body caused by acids, bases, salts, or organic substances), and physical burns (injuries inside or outside the body caused by light or radioactive substances); it does not include electric burns or burns resulting from fires. Skin burned by chemicals will swell, change color, and discharge fluid; the dermal tissue is affected, and in severe cases, internal organs can be impacted. In patients with extensive burns, the severe pain and significant blood loss from the wound sites can lead to infections; in severe cases, this can result in shock and sepsis. The severity of burn injuries is related to the duration of contact and the energy delivered during that contact; the longer the contact time, the more severe the injury. The shorter the contact time, the milder the injury. The greater the impact energy, the more severe the injury. Lower contact energy means less injury. The more concentrated the energy, the more severe the injury. The causes of scalding accidents are the high temperatures generated by substances or equipment used in production. Various high-temperature materials used in production (such as water, steam, flue gas, and high-temperature fluids) can cause scalding accidents when there are leaks in pressure-bearing components such as equipment, pipelines, and valves, or when insulation is inadequate. Such accidents occur frequently; due to their sudden onset, workers do not have time to react, which often results in serious consequences. The chemical energy released by chemicals can cause burns when chemicals are used or mishandled during the production process, and when the human body comes into contact with these chemicals. During laboratory testing, chemical burns are also a common safety hazard; the splashing of strong acids, strong bases, and other irritating chemicals onto the skin or eyes can cause burns to these areas. Case: In 2008, a doctoral student at a research institute in Shanghai failed to wear protective glasses while using peracetic acid; as a result, the acid got into his eyes and caused injuries to both eyes. Another doctoral student accidentally came into contact with triethylaluminum on his hands; since he was not wearing protective gloves and did not rinse the area immediately with plenty of water after the incident, his left hand suffered severe skin damage that required skin grafting. Burns caused to the human body by light energy, radiation, etc., such as injuries to the eyes from welding arcs during inspection, maintenance, and repair work. Prevention of scalding accidents ★ Install external insulation measures for production media with high temperatures, high-temperature equipment within installations, as well as steam-insulated pipelines. For those parts that operators frequently pass by or may come into contact with, in accordance with the requirements of SH3047-93 \"Design Code for Occupational Safety and Health in Petrochemical Enterprises\", insulation measures to prevent burns shall be installed on equipment, pipes, valves, flanges, as well as low-temperature equipment and pipelines whose surface temperature exceeds 60°C and are located within 2.1 meters above the ground or workbench level, and within 0.75 meters of the perimeter of the operating platform. When the opening of the acid or alkali storage tank is more than 1 meter above the ground level or at the same height as the ground, a protective fence should be installed around it along with a tank cover to prevent people from falling in. ★ Strengthen equipment management. An analysis of the burn accidents that have occurred shows that, due to equipment failures, medium leaks that cause burns to people account for a large proportion. Strengthening equipment management and reducing the occurrence of leaks are important preventive measures to avoid burn accidents. Enterprises should implement strict quality assurance measures throughout the entire process of equipment design, manufacturing, procurement, and installation, to ensure that the quality of the equipment remains under control at every stage of product production. Furthermore, regular inspection and maintenance are equally important; companies should establish responsibilities for the use and upkeep of equipment, as well as formulate safety operating procedures to ensure its safe and proper operation. Experience shows that employee inspections are the most important means of detecting problems and early signs of accidents in a timely manner, and companies should pay sufficient attention to employees’ routine inspections. ★ Before inspecting the container, ensure that the medium stored in the system has been completely drained and the pressure is at zero ； When maintaining high-temperature equipment, wait until it has cooled down before proceeding with the work ； When emergency repairs are necessary, gloves and special protective clothing should be worn. Case: On August 1, 1996, during the startup of a benzene dewaxing unit at a certain company, it was discovered that the valve cover was leaking. Feng and others were assigned to handle the issue. During this process, hot water from inside the valve cover sprayed out, scalding Feng’s feet. The reason for this was that it was not checked whether there was pressure or fluid in the pipelines before removing the valve cover. ★ Be careful of your position while working, and avoid areas where the medium might spray out. For example, when reading a level gauge, stand to the side of it; when loosening flanges, do not stand directly in front of them to prevent residual medium from spraying out and causing injury. During boiler ignition or when combustion is unstable, do not stand directly in front of the viewing doors, inspection doors, or burner access holes to avoid being injured by flames. When opening these doors, do so slowly and carefully, with staff standing behind the door and ensuring there are clear escape routes to both sides. ★ Operators must be familiar with the operating procedures and safety precautions, understand the physical and chemical properties of the chemicals they handle, and be aware of the burns that can result from contact with these chemicals as well as the methods for treating such burns. ★ To prevent burns from light, protective glasses must be worn or the eyes covered with colored glass when observing the boiler’s combustion ； When performing welding and cutting tasks, welders must use protective face shields and welding goggles that meet the required safety standards ； At the construction site, make every effort to provide proper protection or isolation for welding and gas cutting operations, in order to prevent burns to oneself or others. ★ Attach great importance to personal protection. Personal protective equipment is essential gear for protecting employees from occupational injuries. Employees should use such equipment appropriately based on the occupational hazards they are exposed to during work. When handling hazardous chemicals, it is necessary to wear protective clothing, safety glasses or face shields, as well as use safe tools ； When working in high-temperature environments, it is necessary to wear heat-resistant work clothes and shoes, as well as heat-resistant gloves and safety equipment ； Goggles should be worn in a chemistry laboratory to protect the eyes from irritating gases and to prevent chemicals, especially strong acids and strong bases, from splashing into the eyes. It is prohibited to pick up any chemicals with bare hands. When using toxic chemicals, rubber gloves must be worn in addition to spatulas and measuring instruments. After the experiment, clean the instruments and equipment immediately, and wash your hands with soap right away. Case: At 22:14 on September 5, 2007, during maintenance work on the acid circulation pump P404 in the sulfuric acid department of a petrochemical company, boiling occurred in the sulfuric acid circulation tank; sulfuric acid sprayed out from the sample collection container, severely burning two maintenance workers who were working on the platform at that time. The cause of the accident was that, with both acid circulation pumps damaged, nitric acid and water were continued to be added to the dry absorption circulation tank V401 in violation of operating procedures; the heat generated from this dilution could not be removed in time, resulting in boiling over in V401. The connection pipe of the sampling liquid collection hopper led straight down into the liquid level inside V401, with no overflow or spill prevention measures such as check valves in place. The maintenance personnel were not wearing acid-resistant suits during the repair work, and there was no supervisor present on site to oversee the operations, which led to the accident. Emergency treatment for scalding accidents: Hot water (steam) burns – When the human body is scalded by hot water (steam), it should be cooled using cold water or ice water. Mild burns require cooling for a few minutes, while severe burns need to be cooled for 30 minutes. In the event of a burn on an area covered by clothing, water should be poured directly on the clothing to cool it down; once cooled, the clothing can be cut away or removed. Once the injured area has been fully cooled, cover it with sterile gauze and receive treatment. Do not apply any ointments before a doctor’s diagnosis to avoid infection. To prevent scarring at the affected area, do not pop the swollen blisters; follow the doctor’s treatment instructions. First aid for burns ★ When the body is burned, one should roll on the ground to extinguish the flames on the body. Do not run in haste, lest the fire grow more intense with the wind. ★ Rinse or soak the burned area with tap water; the lower the water temperature, the better, as long as it is tolerable. On the one hand, it can rapidly lower the temperature, reduce the area of burns, minimize the transfer of heat to deeper layers of tissue, and lessen the depth of the burns ； On the other hand, it can clean the wound and relieve pain. Do not apply colored medications such as mercuric red or gentian violet to burn wounds, as this may interfere with the assessment of the depth of the burn. Also, avoid applying oily substances like toothpaste or ointments to the burn site, in order to reduce the risk of infection and make treatment easier when seeking medical care. If blisters appear, be careful to keep them intact and do not remove the skin over them to avoid infection. First aid for chemical burns: In the case of chemical skin burns, one should immediately leave the area affected, quickly remove contaminated clothing, shoes, socks, etc., and rinse the wound with plenty of flowing water for 20 to 30 minutes (more time is required for strong chemicals) in order to dilute the toxic substances and prevent further damage as well as their absorption through the wound. Do not apply ointments, merthiolate, or gentian violet to fresh wounds, and do not cover them with dirty cloth. In the case of chemical eye burns, it is essential to rinse the eyes immediately with flowing water. While rinsing, keep the eyelids open to ensure that all chemicals trapped under them are thoroughly washed away. If there is no rinsing equipment available on site, you can submerge your head in clean water in a basin, lift the eyelids open, and move the eyeballs back and forth to clean them. If carbide or quicklime particles get into the eyes, a cotton swab dipped in paraffin oil or vegetable oil should be used to remove the particles first, followed by rinsing with clean water.