Research progress on pollutant emission and control from CO, chemical absorption system

Due to its high capture efficiency, relatively mature technology and good adaptability,C02 chemical absorption technology is cur rently the most potential C()2 capture technology for industrial application.However,in C()2 chemical absorption system,absorbent is used to capture C02 in the flue gas,and part of the absorbent and its degradation products are discharged with the flue gas,which not only in creases the loss of absorbent,and further reacts in the atmosphere to form strong carcinogen nitrate amine and nitrosamines.Therefore,it is necessary to effectively control the pollutant emission from C02 chemical absorption system.At present, pollutants are usually controlled by adjusting the operating parameters of the system and using pollutant control means,but there is no universal control method and the pollu tant emission control target value has not been established.In this paper, three emission forms of pollutants in C()2 chemical absorption sys tem were introduced, including physical entrainment, gas and aerosol.The aerosol has high emission and is difficult to be controlled by tra ditional methods.According to the emissions measured by the research institutions, C02 chemical absorption systems of different scales generally have higher emissions.The mechanism of aerosol generation and growth was analyzed.The aerosol emission is mainly pro duced through heterogeneous nuclei,which depends on the existence of condensation nuclei and the supersaturated environment.Based on the experimental and simulation methods,the effects of condensation core of flue gas,inlet temperature of lean liquid,lean liquid load and C02 content of flue gas on the emission of organic amine dominated by aerosols were reviewed.The research on the emission of degradation products,including oxidative degradation and thermal degradation,was briefly introduced.Finally,the control effect,advantages and disad vantages of the current pollutant emission control methods were summarized.The traditional water washing method can effectively control the gaseous emission of organic amines.The traditional mist eliminator has a good control effect on large-size aerosol particles, hut the re moval efficiency of small particles is low.Although wet electric dust removal, steam injection, dry bed and other methods have certain re moval effect,hut the cost is high.Acid pickling can solve the problem of ammonia emission,but it is difficult to recover organic amines.Colloid gas foam method has high efficiency for aerosol removal,but there is a lack of industrial research.In the future,it is necessary to develop new control methods for pollutant emission, which can effectively reduce the emission of pollutants in the form of gas phase and aerosol,and control the industrial investment cost.This method will be the key link for the establishment of advanced carbon capture process system.