Simultaneous removal of NOx and SO2 using two-stage O3 oxidation combined with Ca(OH)2 absorption

• Published in: The Korean journal of chemical engineering Vol. 37; no. 11; pp. 1907 - 1914
• Main Authors: Zou, Yang, Wang, Yan, Liu, Xiaolong, Zhu, Tingyu, Tian, Mengkui, Cai, Maoyu
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2020; 한국화학공학회
• Subjects: Biotechnology; Catalysis; Chemistry; Chemistry and Materials Science; Environmental Engineering; Industrial Chemistry/Chemical Engineering; Materials Science; 화학공학; Iron Ore Sintering Flue Gas; Two-stage Oxidation; NO; Ozone; SO
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-020-0597-z

This paper proposes two-stage O 3 oxidation combined with Ca(OH) 2 for simultaneous removal of NO x and SO 2 (NO x : Nitrogen oxides including NO, NO 2 and N 2 O 5 ). In two-stage oxidation, NO was first oxidized to NO 2 in an oxidation tube, and NO 2 was further oxidized into N 2 O 5 in the spray tower. NO x and SO 2 were simultaneously removed in the spray tower. This method can effectively reduce the extra waste of O 3 caused by the decomposition of N 2 O 5 , especially at high temperature. Effects of various factors on denitrification efficiency were investigated. The results showed that the NO x removal efficiency decreased and O 3 extra consumption ratio increased with the increase of oxidation temperature or oxidation reaction time. When the O 3 /NO molar ratio was 1.8, one-stage O 3 oxidation at 150 o C extra wasted 33.3% of O 3 . With the increase of O 3 concentration at site 2, the NO x removal efficiency first increased and then stabilized. Compared with the one-stage O 3 oxidation-absorption, the two-stage oxidation-absorption improved NO x removal efficiency from 62.5% to 89%. In addition, the increase of CaSO 3 slurry concentration had little effect on the denitrification efficiency.