Study On Process Safety And Reaction Hazard In Peracetic Acid Production

The acetic acid oxidation method is usually applied for peracetic acid production.As the peroxides（hydrogen peroxide and peracetic acid）that are extremely sensitive to heat are involved in the process,the reaction may get out of control at very low temperature,leading to reactor damage caused by high temperature and pressure.What is worse,fire and explosion may occur,affecting the safe production of surrounding equipment.Now,Most of studies focus on thermal safety of simple substances during storage and transportation,while studies on hazard of substances in the reaction system and hazard of the whole reaction process during peracetic acid production are relatively less.In addition,the hazard in static environment such as storage is not far comparable to that in production.In the study,the differential scanning calorimeter（DSC）is used to test and analyze the thermal decomposition of hazardous substances in reaction,obtain thermal decomposition parameters such as heat release of hydrogen peroxide and peracetic acid at different heating rates during scanning.The heat release of hydrogen peroxide and peracetic acid is 682.8J/g and460.2J/g.Advanced kinetics and technology software（AKTS）is used to test and calculate thermodynamics parameters of hydrogen peroxide and peracetic acid,including reaction process,activation energy.In addition,the decomposition reaction rule and the thermal safety index TMRad of peroxides under isothermal condition are predicted and analyzed,obtain TD24 of hydrogen peroxide and peracetic acid are-10.1℃、-1.4℃,?T_add of hydrogen peroxide and peracetic acid are 183.5℃、120.9℃.It can be seen that the possibility is 4 levels and severity is 2 levels for uncontrolled reaction of hydrogen peroxide and peracetic acid.The reaction calorimeter（RC1e）is used to study the thermal hazard of the existing process under the same process conditions.It can be seen that the“one-pot reaction”has less process heat release and is 10.11kJ.The accelerating rate calorimeter（ARC）is used to study thermal decomposition of the reaction product and hydrogen peroxide under the adiabatic condition and obtain more accurate heat release,adiabatic temperature rise?T_ad are 141.2℃、196.1℃,TMRad are 3.1h、7.2h.It can be seen the hazard of the peracetic acid production system mainly comes from the secondary decomposition reaction after the uncontrolled reaction of the reactant and product.Combining ARC and RC1e data,hazard levels of reaction system,reaction product and hydrogen peroxide are classified according to the risk matrix assessment standard.The result shows that the hazard level of the reaction system is Ⅰ,which is acceptable;that of reaction products and hydrogen peroxide is Ⅱ,which is conditionally acceptable.The Dow’s Fire&Explosion Index is used to assess hazard levels of the reactor of the peracetic acid production plant and the hydrogen peroxide tank.The result shows that the reactor and the hydrogen peroxide tank after safety factor compensation is Ⅲ,which is moderate.