Prevention and control measures for hazardous chem

2022-10-02
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Prevention and control measures for hazardous chemical accidents in the workplace

① replacement. The best way to control and prevent chemical hazards is not to use toxic, harmful, flammable and explosive chemicals, but it is difficult to do so. The usual practice is to choose non-toxic or low toxic chemicals to replace toxic and harmful chemicals, and combustible chemicals to replace flammable chemicals

② change the process. Although substitution is the first choice to control the hazards of chemicals, at present, the alternatives available are very limited, especially for technical and economic reasons, it is inevitable to produce and use hazardous chemicals. At this time, chemical hazards can be eliminated or reduced by changing the process. For example, in the past, the production of acetaldehyde from acetylene used mercury as a catalyst. Now it is developed to use ethylene as raw material to produce acetaldehyde through oxidation or chlorination, without mercury as a catalyst. By changing the process, the harm of mercury was completely eliminated

③ isolation. Isolation is to prevent operators from being directly exposed to harmful environment by closing and setting barriers. The most common isolation method is to completely seal the equipment used when the oil delivery handwheel is closed, so that workers will not be exposed to chemicals during operation. Another common isolation method is to isolate the production equipment from the operation room

④ ventilation. Ventilation is the most effective measure to control harmful gas, steam or dust in the workplace. With the help of effective ventilation, the concentration of harmful gas, steam or dust in the air of the workplace is lower than the safe concentration, so as to ensure the health of workers and prevent fire and explosion accidents

ventilation is divided into local exhaust and comprehensive ventilation. Local exhaust is to cover the pollution source and extract the polluted air. The required air volume is small, economical and effective, and convenient for purification and recovery. Comprehensive ventilation is also called dilution ventilation. Its principle is to provide fresh air to the workplace, extract polluted air, and reduce the concentration of harmful gases. 1. The positive deviation of the indicated value is out of tolerance, steam or dust in the workplace. Full ventilation requires large air volume, which cannot be purified and recycled. For point diffusion sources, local exhaust can be used. When using local exhaust, the pollution source should be within the control range of the ventilation hood. In order to ensure the high efficiency of ventilation system, the rationality of ventilation system design is very important. The installed ventilation system should be maintained frequently to make it work effectively

⑤ personal protection. When the concentration of hazardous chemicals in the workplace exceeds the standard, workers must use appropriate personal protective equipment. Personal protective equipment can neither reduce the concentration of harmful chemicals in the workplace nor eliminate harmful chemicals in the workplace, but only act as a barrier to prevent harmful substances from entering the human body. The failure of protective equipment itself means the disappearance of protective barriers. Therefore, individual protection cannot be regarded as the main means to control hazards, but only as an auxiliary measure. Protective equipment mainly includes head protective equipment, respiratory protective equipment, eye protective equipment, body protective equipment, hand and foot protective equipment, etc

⑥ hygiene. Hygiene includes keeping the workplace clean and personal hygiene of operators. Regular cleaning of workplaces, proper disposal of wastes and spills, and keeping workplaces clean can also effectively prevent and control chemical hazards. In operation, we can know the force by measuring the change of output voltage. Personnel should develop good hygiene habits to prevent harmful substances from adhering to the skin and penetrating into the body through low-thickness skin

(2) prevention of fire and explosion accidents of dangerous chemicals

theoretically, the basic principles to prevent fire and explosion accidents: prevent and limit the formation of combustible and explosive systems; Eliminate various ignition sources; Prevent and limit the spread of fire and explosion

① prevent the formation of combustion and explosion system. Control according to the dangerous characteristics of the substance; Prevent the leakage of combustibles; Inert gas protection; Ventilation replacement; Safety monitoring and interlocking. ② Safety control of process parameters. In the process of chemical and petrochemical production, process parameters mainly refer to temperature, pressure, flow, material ratio, etc. Strictly control the process parameters within the safety limit according to the process requirements, and prevent overheating, overpressure and material leakage is one of the basic measures for fire and explosion prevention, and also the basic guarantee for the realization of safe production. ③ Eliminate ignition sources. The fire sources that can cause accidents include open fire, high-temperature surface, impact friction, spontaneous combustion and heating, electrical, electrostatic sparks, chemical reaction heat, light irradiation, etc., and the fire sources must be scientifically and strictly managed. ④ Measures to limit the spread of fire and explosion. Measures to limit the spread of fire and explosion include fire arresting devices, fire arresting facilities, explosion-proof pressure relief devices and isolation

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