ISSN : 1225-0112(Print)
ISSN : 2288-4505(Online)
ISSN : 2288-4505(Online)
Applied Chemistry for Engineering Vol.28 No.6 pp.607-618
DOI : https://doi.org/10.14478/ace.2017.1092
DOI : https://doi.org/10.14478/ace.2017.1092
Various Technologies for Simultaneous Removal of NOx and SO2 from Flue Gas
Abstract
Harmful air pollutants are exhausted from the various industrial facilities including the coal-fired thermal power plants and these
substances affects on the human health as well as the nature environment. In particular, nitrogen oxides (NOx) and sulfur dioxide
(SO2) are known to be causative substances to form fine particles (PM2.5), which are also deleterious to human health. The integrated
system composed of selective catalytic reduction (SCR) and wet flue gas desulfurization (WFGD) have been widely
applied in order to control NOx and SO2 emissions, resulting in high investment and operational costs, maintenance problems,
and technical limitations. Recently, new technologies for the simultaneous removal of NOx and SO2 from the flue gas, such
as absorption, advanced oxidation processes (AOPs), non-thermal plasma (NTP), and electron beam (EB), are investigated in
order to replace current integrated systems. The proposed technologies are based on the oxidation of NOx and SO2 to HNO3
and H2SO4 by using strong aqueous oxidants or oxidative radicals, the absorption of HNO3 and H2SO4 into water at the gas-liquid
interface, and the neutralization with additive reagents. In this paper, we summarize the technical improvements of each
simultaneous abatement processes and the future prospect of technologies for demonstrating large-scaled applications.
substances affects on the human health as well as the nature environment. In particular, nitrogen oxides (NOx) and sulfur dioxide
(SO2) are known to be causative substances to form fine particles (PM2.5), which are also deleterious to human health. The integrated
system composed of selective catalytic reduction (SCR) and wet flue gas desulfurization (WFGD) have been widely
applied in order to control NOx and SO2 emissions, resulting in high investment and operational costs, maintenance problems,
and technical limitations. Recently, new technologies for the simultaneous removal of NOx and SO2 from the flue gas, such
as absorption, advanced oxidation processes (AOPs), non-thermal plasma (NTP), and electron beam (EB), are investigated in
order to replace current integrated systems. The proposed technologies are based on the oxidation of NOx and SO2 to HNO3
and H2SO4 by using strong aqueous oxidants or oxidative radicals, the absorption of HNO3 and H2SO4 into water at the gas-liquid
interface, and the neutralization with additive reagents. In this paper, we summarize the technical improvements of each
simultaneous abatement processes and the future prospect of technologies for demonstrating large-scaled applications.
배출가스의 질소산화물과 이산화황 동시 저감 기술
초록
석탄화력발전소를 포함한 다양한 산업설비에서 유해 대기오염물질이 배출되고 있으며, 이러한 오염물질은 인체 건강 과 자연 생태계에 영향을 준다. 특히, 질소산화물(NOx)와 이산화황(SO2)은 인체 건강에 악영향을 주는 미세먼지(PM2.5) 형성에 원인물질로 알려져 있다. 이러한 NOx와 SO2 배출을 저감하기 위해서 선택적 촉매 환원(SCR)과 습식 탈황 공정 (WFGD)으로 결합된 혼합 시스템이 사용되고 있으나, 높은 설치비용 및 운전비용을 필요로 하며, 유지보수의 문제점, 기술적인 한계점을 가지고 있다. 최근에 이러한 혼합 시스템을 대체하기 위한 NOx, SO2 동시 저감 기술이 연구되고 있으며, 제안된 기술들은 흡수, 고도 산화(AOPs), 저온 플라즈마(NTP), 전자 빔(EB) 등이 있다. 이러한 기술들은 강한 수용성 산화제 및 산화력을 가진 화학활성종에 의한 NOx, SO2를 HNO3, H2SO4 형태로의 산화 반응, 기-액 계면에서 HNO3와 H2SO4 흡수 반응, 화학 첨가제에 의한 중화 반응을 기본으로 하고 있다. 본 논문에서는 각각의 동시 저감 공정에 대한 기술적인 특징과 대용량 처리 공정 응용을 위한 향후 전망을 정리하였다.