| In recent years,the production of glyphosate herbicide has increased greatly due to its high efficiency,low toxicity and environment-friendly characteristics.However,due to the complexity of the synthesis process and the use of methanol,triethylamine,paraformaldehyde,dimethyl phosphite and other flammable and explosive dangerous chemicals,the possibility of safety accidents in the production process is very high.In order to ensure the safe production of glyphosate workshop and avoid or reduce safety accidents in the production process,it is particularly important to identify hazard sources and evaluate the risk of safe production in glyphosate workshop,and put forward prevention and control measures.For the current domestic chemical safety production,there is the fact that the advanced and complicated risk assessment technology is difficult to transplant and apply to the bottom production enterprises.Therefore,in this thesis,the glyphosate production workshop of an enterprise is taken as an example,and the convenient qualitative risk assessments,as well as the advanced quantitative ones,were carried out for the chemical safety productionFirstly,the HAZID hazard identification method with energy as the guide word,combined with butterfly diagram method and risk matrix method,is used to qualitatively evaluate the synthesis reactor unit,hydrolysis unit,methanol methylal recovery unit,crystallization unit,centrifugal drying unit and triethylamine recovery unit in glyphosate production workshop.It was found that the risk levels of reactor reaction out of control and methanol tank leakage in the synthesis reactor unit,methanol leakage in the methanol methylal recovery unit and triethylamine leakage in the triethylamine recovery unit were all level II,which were located in the area of unacceptable risk.Then,the improved Dow Chemical Fire and explosion risk index evaluation method（Dow method）is used to quantitatively analyze the synthetic reactor unit,methanol methylal recovery unit and triethylamine recovery unit with high risk level.The results show that after increasing the personnel safety compensation coefficient and dividing the safety compensation into event prevention type and consequence mitigation type,the F＆EI value of synthetic reactor unit is 155.63,the exposure area is 4984.21 m~2,and the risk level is very high,so safety measures need to be added;The F＆EI value of methanol recovery unit is102.48,the exposure area is 2161.16 m~2,the risk level is medium,and safety measures can be added;The F＆EI value of triethylamine recovery unit is 95.05,the exposure area is1859.15 m~2,and the risk level is relatively light.Finally,with the help of fault tree method and layer of protective analysis method（LOPA）,the out of control reaction of synthesis reactor unit and methanol tank leakage are diagnosed and analyzed,and targeted improvement measures are put forward.The results showed that the reactor reaction was out of control.By increasing the reactor overtemperature alarm,cutting off the heat source after the alarm,and increasing the frequency of personnel inspection,the possibility of consequences was reduced to 2.5×10-7after safety control measures such as timely feedback in case of overtemperature problems,the possibility level is reduced to level 1,the risk value is reduced to 5,the risk level is reduced from level II to level III,and it is located in the risk acceptable area;The leakage of methanol tank is caused by increasing the overpressure alarm of methanol tank,taking measures immediately after the alarm,regularly detecting the safety valve,increasing the frequency of patrol inspection by personnel,and reducing the frequency of consequences to2.5×10-6after the operators find abnormalities and take immediate action and other safety control measures,the possibility level is reduced to level 1,the risk value is reduced to level4,and the risk level is reduced from level II to level IV,which is located in the risk acceptable area.The comprehensive evaluation system and method proposed in this thesis can provide theoretical guidance and decision support for improving the overall production safety of glyphosate enterprises,so as to guarantee the safe production of glyphosate enterprises,and provide practical application reference for the risk assessment of safety production in China’s chemical industry. |
