• Applied Chemistry for Engineering
• /
• v.28 no.6
• /
• pp.607-618
• /
• 2017

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 ($NO_x$) and sulfur dioxide ($SO_2$) are known to be causative substances to form fine particles ($PM_{2.5}$), 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 $NO_x$ and $SO_2$ emissions, resulting in high investment and operational costs, maintenance problems, and technical limitations. Recently, new technologies for the simultaneous removal of $NO_x$ and $SO_2$ 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 $NO_x$ and $SO_2$ to $HNO_3$ and $H_2SO_4$ by using strong aqueous oxidants or oxidative radicals, the absorption of $HNO_3$ and $H_2SO_4$ 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.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.5
• /
• pp.501-512
• /
• 2016

The study evaluated methods to measure condensable fine particles in flue gases and measured particulate matter by fuel and material to get precise concentrations and quantities. As a result of the method evaluation, it is required to improve test methods for measuring Condensable Particulate Matter (CPM) emitted after the conventional Filterable Particulate Matter (FPM) measurement process. Relative Standard Deviation (RSD) based on the evaluated analysis process showed that RSD percentages of FPM and CPM were around 27.0~139.5%. As errors in the process of CPM measurement and analysis can be caused while separating and dehydrating organic and inorganic materials from condensed liquid samples, transporting samples, and titrating ammonium hydroxide in the sample, it is required to comply with the exact test procedures. As for characteristics of FPM and CPM concentrations, CPM had about 1.6~63 times higher concentrations than FPM, and CPM caused huge increase in PM mass concentrations. Also, emission concentrations and quantities varied according to the characteristics of each fuel, the size of emitting facilities, operational conditions of emitters, etc. PM in the flue gases mostly consisted of CPM (61~99%), and the result of organic/inorganic component analysis revealed that organic dusts accounted for 30~88%. High-efficiency prevention facilities also had high concentrations of CPM due to large amounts of $NO_x$, and the more fuels, the more inorganic dusts. As a result of comparison between emission coefficients by fuel and the EPA AP-42, FPM had lower result values compared to that in the US materials, and CPM had higher values than FPM. For the emission coefficients of the total PM (FPM+CPM) by industry, that of thermal power stations (bituminous coal) was 71.64 g/ton, and cement manufacturing facility (blended fuels) 18.90 g/ton. In order to estimate emission quantities and coefficients proper to the circumstances of air pollutant-emitting facilities in Korea, measurement data need to be calculated in stages by facility condition according to the CPM measurement method in the study. About 80% of PM in flue gases are CPM, and a half of which are organic dusts that are mostly unknown yet. For effective management and control of PM in flue gases, it is necessary to identify the current conditions through quantitative and qualitative analysis of harmful organic substances, and have more interest in and conduct studies on unknown materials' measurements and behaviors.