| At present,China still faces the problem of atmospheric complex pollution by ozone(O3)and Particulate Matter(PM)as the main pollutant.Increasing attention has been paid to the management and control of Volatile Organic Compounds(VOCs),which is the key precursors of O3 and PM.At the same time,China publicly stated that "we will strive to achieve carbon peak by 2030 and carbon neutrality by 2060",and has introduced the implementation plan of"Increasing the collaborative control of VOCs and greenhouse gases" in reducing pollution and carbon synergies.The mainstream technology of current VOCs terminal control technology are combustion and adsorption,the previous evaluation of treatment technology is mainly concerned with the removal efficiency of VOCs,and still lack of the research about relevant terminal equipment itself in the production process and operation process of the comprehensive environmental benefits including greenhouse gas emissions.In this context,it is of great significance to study the synergistic effects and comprehensive environmental benefits of VOCs typical treatment technologies in the life cycle of pollution reduction and carbon reduction.Based on the Life Cycle theory,this paper first selected VOCs combustion method and activated carbon adsorption method devices as the research objects,and carried out Life Cycle Assessment(LCA)on the treatment equipment.By studying the input and output of raw materials and energy in different links of the production process of the equipment,The environmental impact of its production process was analyzed.Secondly,this paper studied the VOCs emission rate,VOCs activity,carbon emissions through gas sampling analysis,studied the VOCs pollutant removal efficiency and energy consumption in the operation process of exhaust gas combustion equipment in key VOCs industry,analyzed the synergistic effect of pollution reduction and carbon reduction of treatment technology and the environmental impact load(EIL)in the use process.Finally,based on scenario analysis,the influence of low-carbon transformation of energy production structure on the synergistic effect of pollution reduction and carbon reduction of VOCs treatment technology was studied.At the same time,the environmental benefits of the life cycle of VOCs waste gas treated by combustion method and activated carbon adsorption method were studied.To provide a reference basis for measuring the synergistic effects of pollution and carbon reduction and comprehensive environmental benefits of VOCs treatment in the life cycle under different scenarios.The main results of this paper are as follows:(1)Based on LCA,the environmental impacts of the Regenerative Thermal Oxidation(RTO)and activated carbon adsorption equipment with low-medium-high air volume during the production process were analyzed,and the contribution of the production process to 11 types of environmental impacts,such as global warming,photochemical oxidation,acidification,etc.The results showed that the contribution of RTO production equipment to each environmental impact category was 10～30 times of that of activated carbon adsorption equipment when the treatment ability of the two equipment is similar.The production of an activated carbon adsorption equipment above 6000 m3/h will cause at least 551.8 kg of CO2 emissions,and the production of an RTO equipment above 10000 m3/h will cause at least 20600.0 kg of CO2 emissions.Within the boundaries of this research,the contribution of production RTO and activated carbon adsorption equipment to the environmental impact mainly comes from the use of refractory and cable,and the use of motor,respectively.Therefore,the improvement of the production process of equipment can be carried out from the aspects of optimizing the line layout to reduce the cable usage,optimizing the heat storage material to improve the heat storage capacity and selecting the appropriate motor.(2)Gas sampling analyzed 9 typical combustion devices such as RTO and Catalytic combustion(CO)were used to evaluate the treatment effect of exhausted gas and the synergistic effect of pollution reduction and carbon reduction from key VOCs industries.The results showed that the treatment efficiency of RTO equipment for 53.91～3126.79 mg/m3 waste gas was 96.33%～99.59%,while that of CO equipment for 11.25～257.22 mg/m3 waste gas was 94.41%～97.32%.The reduction rates of ozone generation potential were 93.33%～99.24%,and the reduction rates of secondary organic aerosol generation potential were 90.10%～99.27%.Although combustion method had an excellent overall removal effect on VOCs,it also caused some VOCs emissions and activity increased(mainly alkanes and alkenes,including acetylene,ethylene,propylene and propane components).At the same time,the operation process of combustion method device caused different degrees of carbon emissions.After comprehensively considering the contribution of energy,power resource input and combustion conversion to carbon emissions in the operation process,the synergistic effect coefficient S1 of the combustion method on VOCs and CO2 emission reduction ranges from-145.65 to 4.59,and the synergistic effect coefficient S2 of O3 and CO2 emission reduction ranges from-91.21 to 7.37.With the exception of equipment Ⅲ,which originally accounted for a large proportion of greenhouse gases in the exhaust,all other equipment had contribution to increase emissions of greenhouse gases.In summary,if the current situation continues to operate for one year,each combustion equipment can reduce 1.34～984.94 tons of VOCs emissions,but will cause 182.60～2459.33 tons of CO2 emissions.(3)The product life cycle method and scenario analysis method were used to analyze the EIL of the actual operation of the combustion or activated carbon adsorption equipment and the RTO and activated carbon adsorption technologies under differentscenarios with different air volume and concentration of VOCs,so as to seek a better path to reduce pollution and carbon synergies.The results showed that most of the combustion equipment can achieve positive environmental benefits by combining the calculation of standard human equivalent and weight,but for equipment Ⅱ and Ⅵ whose intake concentration of VOCs was only 53.91 and 11.25 mg/m3(corresponding emission rates are 0.73 and 0.68 kg/h,respectively),the environmental benefits can also be changed from negative to positive when activated carbon dispersionadsorption-concentrated regeneration technology was used as an alternative technology.The incremental environmental benefit after replacement was equivalent to reducing the EIL of about 134 and 39 people.person.Therefore,for exhaust gas with low emission rate(such as below about 1.0 kg/h in this study),using activated carbon dispersion-adsorption-centralized regeneration technology as the treatment technology and the same batch of activated carbon regeneration twice had better environmental benefits than the combustion treatment technology.Scenario analysis was used to analyze the influence of different energy production structures on the synergistic effect of VOCs emission reduction and carbon emission reduction.It was found that when the proportion of non-fossil energy in energy production structure was increased,the synergistic emission reduction effect of VOCs and CO2 could be significantly improved.Considering the production and use process of the equipment,the EIL value of the exhaust gas treated by different technologies with different emission rates in its whole life cycle was analyzed.The results show that the production process of the RTO and adsorption equipment had little impact on the environment when the service life is as long as 5～10 years. |
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