• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.607-618
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• 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 the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.658-663
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• 2018

Current measuring methods for air quality are based on ground measurement networks and satellite data. New methods of collecting evidence with advanced sensors are needed because current methods have limitations in collecting evidence for the illegal emission of air pollutants at narrow areas or specific sites. This study analyzed the possibility of using an ultraviolet hyperspectral sensor to measure the concentration of nitrogen dioxide and sulfur dioxide. Two types of spectra were used: simulated spectra for gases with various concentrations using a radiative transfer model and observed spectra for each gas for a concentration. To understand the possibility of using a hyperspectral sensor, the differences between the simulated spectra and the observed spectra were analyzed, and the variation of simulated spectra were then analyzed according to the concentration. The results showed good agreement between observed spectra and simulated spectra. In addition, the absorption depth at specific wavelengths in the simulated spectra had a very strong correlation with the gas concentration. The gas concentration could be estimated using the hyperspectral sensor. In the future, validation would be needed to estimate the gas concentration through observations of various concentrations of gases using a hyperspectral sensor.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1241-1248
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• 2010

In large-scale production of hydrogen, a PHE (Process Heat Exchanger) is a key component because the heat required to carry out the Sulfur-Iodine chemical reaction that yields hydrogen is transferred from a VHTR (Very High Temperature Reactor) by the PHE. Korea Atomic Energy Research Institute established a helium gas loop for conducting performance test of components that are used in the VHTR. In this study, as a part of high-temperature structural-integrity evaluation of a designed PHE prototype that is scheduled to be tested in the helium gas loop, we carried out high-temperature structural-analysis modeling, thermal analysis, and thermal-expansion analysis for the designed PHE prototype. An appropriate constraint condition is proposed at the end of the in-flow and out-flow pipelines of the primary and secondary coolants and the proposed constraint condition will be applied to the design of the performance-test loop setup for the designed PHE prototype.

• Membrane Journal
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• v.22 no.3
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• pp.201-207
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• 2012

In this study, we investigated permeation of single gas ($N_2$, $O_2$, $CF_4$, and $SF_6$) through flat sheet membrane composed of PDMS (poly-dimethylsiloxane) and PEBAX (polyether block amides). Gas permeation experiment was performed with various feed pressure. Permeability was estimated using permeation flux measured by continuous-flow technique. The permeability of gases except $SF_6$ in PDMS were decreased with the upstream pressure increased. $SF_6$ is much more permeable than $CF_4$, which is due to higher critical temperature of $SF_6$. The permeability decreased in the following order: $O_2$ > $N_2$ > $SF_6$ > $CF_4$. On the other hand, the permeability of gases in PEBAX followed the order: $O_2$ > $N_2$ > $CF_4$ > $SF_6$ which are opposite of the order of kinematic diameter (${\AA}$)($SF_6$ > $CF_4$ > $N_2$ > $O_2$). The $SF_6/CF_4$ pure gas selectivity in PDMS was 2.1 at 0.7 MPa.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1409-1416
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• 2015

The change of temperature influences on the various aspect, especially human health, plant and animal's growth, economics, industry, and culture of the country. In this article, the autoregressive error (ARE) model has been considered for analyzing the monthly temperature data at the Suwon monitoring site in Korea. In the ARE model, five meteorological variables, four greenhouse gas variables and five pollution variables are used as the explanatory variables for the temperature data set. The five meteorological variables are wind speed, rainfall, radiation, amount of cloud, and relative humidity. The four greenhouse gas variables are carbon dioxide ($CO_2$), methane ($CH_4$), nitrous oxide ($N_2O$), and chlorofluorocarbon ($CFC_{11}$). And the five air pollution explanatory variables are particulate matter ($PM_{10}$), sulfur dioxide ($SO_2$), nitrogen dioxide ($NO_2$), ozone ($O_3$), and carbon monoxide (CO). Among five meteorological variables, radiation, amount of cloud, and wind speed are more influence on the temperature. The radiation influences during spring, summer and fall, whereas wind speed influences for the winter time. Also, among four greenhouse gas variables and five pollution variables, chlorofluorocarbon, methane, and ozone are more influence on the temperature. The monthly ARE model explained about 43-69% for describing the temperature.

• Journal of Animal Environmental Science
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• v.16 no.3
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• pp.175-180
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• 2010

Many greenhouse gases occur naturally, such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Others such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride ($SF_6$) result exclusively from human industrial processes. Current global warming has been linked to anthropogenic greenhouse gas concentration increases. Methods to quantify greenhouse gas emissions during animal agriculture and the possibility to apply those to circumstance in the world were studied. Various chamber methods with trace gas analyzer (TGA) were used to quantify greenhouse gas emissions from stored manure. Methane fluxes from pails storing liquid swine manure were measured. Methane emissions increased a little with time and mean was 393.2 ${\mu}g\;m^{-2}\;s{-1}$ (standard error : 4 ${\mu}g\;m^{-2}\;s{-1}$).

• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.450-458
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• 2012

In order to reduce the effects of greenhouse gas (GHG) emissions, the South Korean government has announced a special platform of technologies as part of an effort to minimize global climate change. To further this effort, the Korean government has pledged to increase low-carbon and carbon neutral resources for biofuel derived from biomass to replace fossil and to decrease levels of carbon dioxide. In general, second generation biofuel produced form woody biomass is expected to be an effective avenue for reducing fossil fuel consumption and greenhouse gas (GHG) emissions in road transport. It is important that under the new Korean initiative, pilot scale studies evolve practices to produce biomass-to-liquid (BTL) fuel. This study reports the quality characteristics of F-T(Fischer-Tropsch) diesel for production of BTL fuel. Synthetic F-Tdiesel fuel can be used in automotive diesel engines, pure or blended with automotive diesel, due to its similar physical properties to diesel. F-T diesel fuel was synthesized by Fischer-Tropsch (F-T) process with syngas($H_2$/CO), Fe basedcatalyst in low temperature condition($240^{\circ}C$). Synthetic F-T diesel with diesel compositions after distillation process is consisted of $C_{12}{\sim}C_{23+}$ mixture as a kerosine, diesel compositions of n-paraffin and iso-paraffin compounds. Synthetic F-T diesel investigated a very high cetane number, low aromatic composition and sulfur free level compared to automotive diesel. Synthetic F-T diesel also show The wear scar of synthetic F-T diesel show poor lubricity due to low content of sulfur and aromatic compounds compared to automotive diesel.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.315-333
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• 2009

In this study, the hydrochemical and the isotopic characteristics of major streams in the Daejeon area were investigated during rainy and dry seasons. The stream water shows the electrical conductivity of the range of $37{\sim}527{\mu}s$/cm, and pH $6.21{\sim}9.83$. The chemical composition of stream waters can be grouped as three types: the upper streams of Ca(Mg)-$HCO_3$ type, Ca(Mg)-$SO_4(Cl)$ type of middle streams flowing through urban area, and Na(Ca)-$HCO_3$(Cl, $SO_4$) type of the down streams. Based on in-situ investigation, the high pH of stream waters flowing through urban area is likely to be caused by the inflow of a synthetic detergent discharging from the apartment complex. The electrical conductivity of stream waters at a dry season is higher than those of at a rainy season. We suggest that the hydro-chemical composition of stream waters in the Daejeon area was affected by the discharging water from the sewage treatment facilities and anthropogenic contaminants as well as the interaction with soil and rocks. ${\delta}D$ and ${\delta}^{18}O$ values of the stream waters show the relationship of ${\delta}D=6.45{\delta}^{18}O-7.4$, which is plotted at a lower area than global meteoric water line(GMWL) of Craig(1961). It is likely that this isotopic range results from the evaporation effect of stram waters and the change of an air mass. The isotope value shows an increasing trend from upper stream to lower stream, that reflects the isotopic altitude effect. The relationship between ${\delta}^{13}C$ and $EpCO_2$ indicates that the carbon as bicarbonate in stream water is mainly originated from $CO_2$ in the air and organic materials. The increasing trend of ${\delta}^{13}C$ value from upper stream waters to lower stream waters can be attributed to the following reasons: (1) an increasing dissolution of $CO_2$ gas from a contaminated air in downtown area of the Daejeon, and (2) the increment of an inorganic carbon of groundwater inflowed into stream by base flow. Based on the relationship between ${\delta}^{34}S$ and $SO_4$ of stream waters, the stream waters can be divided into four groups. $SO_4$ content increases as a following order: upper and middle Gab stream${\delta}^{34}S$ value decreases as above order. ${\delta}^{34}S$ value indicates that sulfur of stream waters is mainly originated from atmosphere, and is additionally supplied by pyrite source according to the increase of sulfate content. The sulfur isotope analysis of a synthetic detergent and sewage water as a potential source of the sulfur in stream waters is furtherly needed.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.157-164
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• 2016

In this study, researchers performed preliminary design and numerical analysis for a pilot-scale helium heating system intended to support full-scale construction for a sulfur-iodine (SI) cycle. The helium heat exchanger used a liquefied petroleum gas (LPG) combustor. Exhaust gas velocity at the heat exchanger outlet was approximately 40 m/s based on computational thermal and flow analysis. The maximum gas temperature was reached with six baffles in the design; lower gas temperatures were observed with four baffles. The amount of heat transfer was also higher with six baffles. Installation of additional baffles may reduce fuel costs because of the reduced LPG exhausted to the heat exchanger. However, additional baffles may also increase the pressure difference between the exchanger's inlet and outlet. Therefore, it is important to find the optimum number of baffles. Structural analysis, followed by thermal and flow analysis, indicated a 3.86 mm thermal expansion at the middle of the shell and tube type heat exchanger when both ends were supported. Structural analysis conditions included a helium flow rate of 3.729 mol/s and a helium outlet temperature of $910^{\circ}C$. An exhaust gas temperature of $1300^{\circ}C$ and an exhaust gas rate of 52 g/s were confirmed to achieve the helium outlet temperature of $910^{\circ}C$ with an exchanger inlet temperature of $135^{\circ}C$ in an LPG-fueled helium heating system.

• Journal of Life Science
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• v.32 no.12
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• pp.971-978
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• 2022

Sulfur-oxidizing, ammonium-oxidizing, and nitrogen-oxidizing media were used to isolate bacteria to degrade malodor gas effectively in piggery manure or soil. Twelve different strains were isolated: Paenibacillus amylolyticus, Rhodococcus jostii, Rhodococcus qingshengii, Rhodococcus opacus, Alcaligenes faecalis, Alcaligenes faecalis, Kastia adipate, Kastia adipata, Microbacterium oxydans, Halomonas campisalis, Acinetobacter oleivorans, and Micrococcus luteus. By inoculating each strain in the piggery liquid manure by 1%, the pH in most strain treatments was maintained at 8.0. Total bacterial counts were maintained at 7.3~7.9 log CFU/ml until 15 days, and then they dropped dramatically down to 5.1~5.5 log CFU/ml. On the 30th day, the treatment group inoculated with Rhodococcus opacus SK2659 showed a relatively high level of ammonium nitrogen removal, which was 39% of that of the control group. When Rhodococcus opacus SK2659 was inoculated, H2S concentration after 100 days was 3.23% compared with the control (no inoculation), suggesting that Rhodococcus opacus SK2659 is an excellent strain for removing malodor gas. The gas production of the treatments was lower than that of the control. The total accumulated amount of gas production in most strain treatments was a quarter of the gas production compared to the control throughout the experimental periods. Acinetobacter oleivorans SK2675 showed the lowest level at 12.39% compared to the control in gas production. In conclusion, the use of mixture strains, such as Rhodococcus opacus SK2659 and Acinetobacter oleivorans SK2675 isolated in this study could increase the efficacy of malodor gas reduction in the biological treatment of piggery manure.