하이브리드 SNCR-SCR 공정의 질소산화물 저감특성을 파일럿 규모의 흐름반응기를 이용하여 고찰하였다. SNCR 공정의 질소산화물 저감효율은 970 oC에서 80% 수준이었으며 하이브리드 SNCR-SCR 공정은 NSR = 2.0, 940 ℃에서 92%의 저감율을 보였다. SNCR 단일 공정과 비교할 때, 하이브리드 SNCR-SCR 공정은 940 ℃보다 낮은 저온영역에서 보다 효과적이었다. 암모니아 유출농도는 비교적 높은 공간속도조건에서 1 ppm 이하로 유지되었으며 요구되는 촉매양은 SCR 단일공정과 비교할 때 2/3 수준으로 감소하였다. 질소산화물 저감을 위한 하이브리드 SNCR-SCR 공정의 주요인자는 SNCR 공정에 분사되는 요소용액의 질소산화물에 대한 선택도와 생성되는 암모니아 농도로 조사되었다.
DeNOx characteristics of hybrid SNCR-SCR process have been investigated in a pilot scale flow reactor. DeNOx efficiency of SNCR reaction was about 80% at 970 ℃ and hybrid SNCR-SCR process showed 92% at 940 ℃ with NSR = 2.0. Compared to SNCR process alone, hybrid SNCR-SCR process was more effective at cool side, which is lower than 940 ℃. It should be also noted that ammonia slip from hybrid SNCR-SCR process was below 1ppm at the condition of higher space velocity and the required catalyst volume can be decreased to 2/3 of SCR process. Key factors for DeNOx efficiency of hybrid SNCR-SCR process were found to be NH3 concentration and NOx selectivity of urea injected in SNCR process.
Gentemann AMG, Caton J, “Decomposition and Oxidation of a Urea-Water Solution as Used in Selective Non-Catalytic Removal(SNCR) Processes,” 2nd Joint Meeting of the United States Sections of the Combustion Institute, 2001 Spring Technical Conference, 2001
Gullett BK, Lin ML, Groff PW, Chen JM, J. Air Waste Manage. Assoc., 44, 1188, 1994