Study on risk prevention and control for custom-built gas combustion devices in college and university laboratories
[Objective]Most gas combustion devices used in university laboratories are custom-built.Given the widespread use of mixed gases,both the devices and experiments pose significant risks.Inadequate consideration of safety during the design,manufacture,and operation of these devices increases the likelihood of explosion accidents,which can result in severe injuries and property damage.Therefore,engineering control measures should be implemented to reduce the risk of such accidents.[Methods]This paper proposes using the Le Chatelier formula to estimate the explosion limits of combustible mixed gases.It emphasizes creating a flammability diagram for combustible gas-inert gas-oxygen mixtures and presents the combustion and explosion characteristics of mixed gases with varying volume fractions under standard temperature and pressure conditions.This approach offers a quantitative method for mitigating explosion risks by incorporating inert gases into combustion experiments.Additionally,the paper classifies combustion devices into two categories:normal pressure burners and deflagration/detonation devices.[Results]A comparison of the two types of devices reveals that deflagration/detonation devices pose a higher safety risk.When preparing and handling combustible mixed gases in these devices,special attention should be given to the impact parts of the device during gas flow,as these components are more prone to abnormal temperature increases.This paper estimates the temperature after adiabatic compression of commonly used combustible gases,such as methane and oxygen,and suggests that adiabatic compression in the negative pressure state of impact parts may lead to accidental combustion and explosion.Moreover,the explosion hazards associated with gas combustion devices are discussed from several perspectives,including the explosion temperatures and pressures of commonly used combustible gases in the laboratory and the effects of explosion overpressure on human health.[Conclusions]From the standpoint of inherent safety,the following recommendations are proposed:① Relatively safe combustible gases should be chosen for experimental schemes whenever possible.Inert gases should be selected based on their inerting capacity.Normal-pressure burners should be chosen,or the volume of the combustion chamber and gas mixing tank in deflagration/detonation devices should be minimized as much as feasible.② Experimental devices should be equipped with appropriate valves,impact parts should be minimized,and a status monitoring and control system should be used to promptly address abnormal situations.Additionally,filters,flame arresters,pressure relief valves,and other necessary safety features should be installed.③ The laboratory environment must meet the requirements for combustion experiments.Devices with explosion potential should be isolated.The room should be equipped with combustible gas detection and alarm systems,adequate ventilation,explosion-proof electrical equipment,and complete emergency supplies.④ The configuration and proper use of personal protective equipment should be standardized.By implementing a comprehensive set of explosion prevention and control measures,accidents can be prevented,their progression can be managed,their consequences can be mitigated,and the overall safety of combustion experiments can be improved.
premix gascombustion devicesabnormal temperature rise of impact partsadiabatic compressionexplosion risk prevention and control
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