Investigation On Deflagration Characteristics And Inerting Inhibition Mechanism Of Acetaminophen Dust

Dust explosion is the main threat to industry safety production hazard,in recent years,with the mechanization of powder related industry and scale,the dust explosion accidents are increasing,especially in the pharmaceutical industry,raw materials are mostly in powder form,in the process of production,it is easy to spread and then explode,which brings serious challenges to safe production.Therefore,effective prevention and control of dust explosion have important theoretical and practical significance.As an important mean of safety protection,inerting and suppression technologies belong to active and passive explosion-proof measures respectively.Based on this,the study focuses on the subject of paracetamol,the deflagration characteristics of paracetamol under inerting/inhibiting conditions were investigated using the common pharmaceutical excipients aluminium hydroxide and silica gel dry water material as inerting/inhibiting agents,and reveals its inerting inhibitory mechanisms.The research results are expected to provide some theoretical guidance for the design of explosion protection in pharmaceutical companies.The deflagration characteristics of paracetamol dust under different concentration and ignition energy conditions were studied.By the negative feedback effect of the pyrolysis time of dust particles and the propagation of the deflagration flame,the flame shows pulsating propagation.When the concentration of paracetamol dust is 500 g/m~3and the ignition energy is 20 J,the deflagration reaction is the most intense,the propagation time and ignition delay time of the deflagration flame are the shortest,the brightness and saturation of the flame are the highest,flame fills the pipe without breakage,with maximum parameters such as peak flame temperature and flame speed.The changes in the deflagration characteristics of paracetamol under inerting conditions were investigated and it was found that the inerting agent aluminium hydroxide/silica dry water mixed with paracetamol disrupted the thermal equilibrium of the reaction,making the flame pulsation phenomenon more pronounced,the deflagration intensity reduced and the peak flame temperature and flame speed inerted.As the amount of inerting agent increases,the amount of deflagration residue also gradually increases.When the mass fraction of aluminium hydroxide and silica gel dry water was increased to 100 wt%and 60 wt%,the paracetamol deflagration flame was suppressed.The deflagration characteristics of paracetamol under inhibition condition were studied.It is found that the deflagration flame is inhibited by nitrogen and carbon dioxide under the action of gas phase inhibitors.Especially,the brightness and saturation of flame change obviously under the action of carbon dioxide.Under the action of two phase inhibitor(nitrogen-carbon dioxide loaded with aluminum hydroxide-silica gel dry water):With the increase of solid phase inhibitor content,the deflagration flame is gradually suppressed,and the flame propagation speed and temperature are greatly reduced.When the amount of aluminum hydroxide/silica gel dry water is 80 wt%and 60 wt%under nitrogen loading,or the amount of aluminum hydroxide/silica gel dry water is 60 wt%and 40 wt%under carbon dioxide loading,the deflagration flame is significantly suppressed.Combined with the deflagration and pyrolysis characteristics of paracetamol and the analysis of deflagration products,the action mechanism of gas-solid two phase inerting inhibition was revealed.Gas inhibitors Nitrogen and carbon dioxide act mainly by diluting oxygen concentration and thermal effect.The mechanism of aluminum hydroxide is mainly decomposition endothermic,reducing oxygen content and free radical content,shielding heat and oxygen.Silica gel dry water has the characteristics of low thermal conductivity,large specific surface area and high water content.