Regeneration of waste SCR catalyst by air lift loop reactor

• Published in: Journal of Central South University Vol. 20; no. 5; pp. 1314 - 1318
• Main Authors: Lee, Jung-bin, Eom, Yong-seok, Kim, Jun-han, Chun, Sung-nam
• Format: Journal Article
• Language: English
• Published: Heidelberg Central South University 01.05.2013
• Subjects: Engineering; Metallic Materials; air lift loop reactor catalyst; selective catalyst reduction; regeneration; nitrogen oxide
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-013-1617-5

A solution of 0.1 mol/L to 1.0 mol/L H 2 SO 4 can dissolve alkali metals and alkaline earth metals which weaken an active site of SCR catalyst. The waste catalyst washed with 0.5 mol/L H 2 SO 4 regained the best catalytic activity. When a concentration of the sulfuric acid is less than 0.5 mol/L, sufficient cleaning effects cannot be obtained. In contrast, when the concentration is greater than 1.0 mol/L, the active components, vanadium and tungsten are undesirably eluted. The total BET surface of the catalyst regenerated by air lift loop reactor showed almost the same as that of fresh catalyst due to the removal of insoluble compounds which may be penetrated into pores of catalyst. The addition of a solution of 0.075 mol/L ammonium vanadate (NH 4 VO 3 ) and 0.075 mol/L ammonium paratungstate (5(NH 4 ) 2 O·12WO 3 ·5H 2 O) to 0.1 mol/L H 2 SO 4 significantly increases the activity of the waste catalyst.