The co-removal of CO_(2)while removing SO_(2)and NOxfrom industrial flue gas has great potential of carbon emission reduction but related research is lacking.In this study,a wet scrubbing process with various urea sol...The co-removal of CO_(2)while removing SO_(2)and NOxfrom industrial flue gas has great potential of carbon emission reduction but related research is lacking.In this study,a wet scrubbing process with various urea solutions for desulfurization and denitrification was explored for the possibility of CO_(2)absorption.The results showed that the urea-additive solutions were efficient for NOxand SO_(2)abatement,but delivered<10%CO_(2)absorption efficiency.The addition of Ca(OH)_(2)dramatically enhanced the CO_(2)absorption,remained the desulfurization efficiency,unfortunately restricted the denitrification efficiency.Among various operating parameters,pH of solution played a determining role during the absorption.The contradictory pH demands of CO_(2)absorption and denitrification were observed and discussed in detail.A higher pH of solution than 10 was favorable for CO_(2)absorption,while the oxidizing of NO to NO_(2),NO_(2)^(-)or NO_(3)^(-)by NaClO_(2)was inhibited in this condition.When7<pH<10,it was favorable for the conversion and absorption of NO and NOx.However,the conversion of HCO_(3)^(-)to CO_(3)^(2-)was significantly inhibited,hence preventing the absorption of CO_(2).Large part of Ca(OH)_(2)became CaCO_(3)with a finer particle size,which covered the unreacted Ca(OH)_(2)surface after the reaction.Kinetic analysis showed that the CO_(2)absorption in urea-NaClO_(2)-Ca(OH)_(2)absorbent was controlled by chemical reaction in early stage,then by ash layer diffusion in later stage.展开更多
基金supported by the National Key Research and Development Plan of China (Nos.2019YFC0214300 and 2020YFF0408886)the Central Public-interest Scientific Institution Basal Research Fund of China (Nos.PM-zx703-202104059,PM-zx703-202104-087,and PM-zx703-202204-159)the Project of Science and Technology Program of Guangzhou,China (No.202102020135)。
文摘The co-removal of CO_(2)while removing SO_(2)and NOxfrom industrial flue gas has great potential of carbon emission reduction but related research is lacking.In this study,a wet scrubbing process with various urea solutions for desulfurization and denitrification was explored for the possibility of CO_(2)absorption.The results showed that the urea-additive solutions were efficient for NOxand SO_(2)abatement,but delivered<10%CO_(2)absorption efficiency.The addition of Ca(OH)_(2)dramatically enhanced the CO_(2)absorption,remained the desulfurization efficiency,unfortunately restricted the denitrification efficiency.Among various operating parameters,pH of solution played a determining role during the absorption.The contradictory pH demands of CO_(2)absorption and denitrification were observed and discussed in detail.A higher pH of solution than 10 was favorable for CO_(2)absorption,while the oxidizing of NO to NO_(2),NO_(2)^(-)or NO_(3)^(-)by NaClO_(2)was inhibited in this condition.When7<pH<10,it was favorable for the conversion and absorption of NO and NOx.However,the conversion of HCO_(3)^(-)to CO_(3)^(2-)was significantly inhibited,hence preventing the absorption of CO_(2).Large part of Ca(OH)_(2)became CaCO_(3)with a finer particle size,which covered the unreacted Ca(OH)_(2)surface after the reaction.Kinetic analysis showed that the CO_(2)absorption in urea-NaClO_(2)-Ca(OH)_(2)absorbent was controlled by chemical reaction in early stage,then by ash layer diffusion in later stage.
