| Hydrazine hydrate is an important chemical raw material and the main material in various chemical production.Nowadays,under the situation that resources and environment are facing more and more pressure,such enterprises are also facing the need of upgrading.This research takes Xinren Chemical Limited as an example to replace urea production process with ketone-azide production process.By using the original project,environmental impact report of technological transformation project,the acceptance and acceptance monitoring report of original project and technological transformation project,combined with field investigation and information inquiry,the technical transformation of hydrazine hydrate project in Xinren Chemical Limited is carried out before and after the technological transformation of hydrazine hydrate project.The changes of fresh water consumption and discharge are analyzed,which can provide reference for the technical reform of hydrazine hydrate production enterprises in the future.The comparative analysis can draw the following conclusions and contents:(1)The fresh water consumption of the original project(urea method)is 6.33 m3/t,the fresh water consumption of the technological transformation project(ketonitride method)is 25.53 m3/t,and the fresh water consumption of the technological transformation project has increased three times,which has increased the pressure on the local water supply.(2)Emissions and effects of organized pollutants:through the transformation of boilers,fuel is replaced by natural gas,particulate matter emissions are reduced by 251.88t/a,99.7%;SO2 emissions are reduced by 477.74t/a,nearly 100%;NOx emissions are reduced by 703.67t/a,99.2%.The emission reduction of particulate matter per unit product is 12.57 kg/t,SO2 emission is 22.39 kg/t and NOx emission is 35 kg/t.It can be seen that the emission of atmospheric pollutants is significantly reduced after technological transformation,which plays a positive role in improving the local atmospheric environmental quality.(3)Discharge and impact of non-organized pollutants at factory boundary:After technological renovation,the concentration values of ammonia,particulate matter and hydrogen sulfide discharged from the same non-organized pollutants as those from the original process have increased,mainly because the project site has been built in an industrial park,and there are similar pollutant discharging enterprises around,but the monitoring concentration values conform to the national discharge.However,after technological renovation,toluene and non-methane total hydrocarbon organic pollutants have been added to the process air pollution,and the plant boundary concentration has reached the standard,but it has potential adverse effects on the atmospheric environment.(4)Solid waste emission and its impact:From the total amount,the solid waste discharged from the original process products is 10.43 t/t,mainly the boiler ash,desulfurization slag and salt slag,etc.The solid waste discharged from the unit products of the process after the technological transformation is 2.75 t/t,and the solid waste discharged from the unit products has decreased by 73.6%,mainly due to the large number of boiler ash,desulfurization slag and salt slag.The fuel is changed from coal to natural gas,and the ash and slag of the boiler are reduced more.However,new hazardous solid wastes have been added to the technical renovation project,which not only increases the management and treatment costs of enterprises,but also increases the local environmental risks and treatment costs.(5)Owing to the energy change after the technological transformation,the total amount of CO2 emission reduction achieved by enterprises is 65205t/a.According to the CO2 production per unit product,the production per unit product of the original process is 5.15t/t,and the production per unit product of the process is 3.14t/t after the technological transformation,which reduces the CO2 emission per unit product by 39%. |
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