• Clean Technology
• /
• v.17 no.1
• /
• pp.69-77
• /
• 2011

The intrinsic $CO_2$ separation and hydrogen production system is a novel concept using oxidation and reduction reactions of oxygen carrier for both $CO_2$ capture and high purity hydrogen production. The process consists of a fuel reactor (FR), a steam reactor (SR) and an air reactor (AR). The natural gas ($CH_4$) is oxidized to $CO_2$ and steam by the oxygen carrier in FR, whereas the steam is reduced to hydrogen by oxidation of the reduced oxygen carrier in SR. The oxygen carrier is fully oxidized by air in AR. In the present study, the chemical looping moving bed reactor having 200 L/h hydrogen production capacity is designed and the hydrodynamic properties were determined. Compared with other reactors, two moving bed reactors (FR, SR) were used to obtain high conversion and selectivity of the oxygen carrier. The desirable solid circulation rates are calculated to be in the range of $20{\sim}100kg/m^2s$ from the conceptual design. The solid circulation rate can be controlled by aeration in a loop-seal. To maintain the gas velocity in the moving beds (FR, SR) at the minimum fluidization velocity is found to be suitable for the stable operation. The solid holdup in moving beds decrease with increasing gas velocity and solid circulation rate.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.14 no.4
• /
• pp.257-266
• /
• 2008

PAHs are of mainly anthropogenic origin from urban runoff, oil spill and combustion of fossil fuels. Some PAHs are potentially carcinogenic and mutagenic to aquatic organisms. This study was carried out to survey the contamination of PAHs in the column sediments around Gwangyang bay. Yeosu petrochemical industrial complex, POSCO(Pohang steel compony) and Gwangyang container harbor are located near the bay. The column sediments were collected at 4 stations(A, B, C and D) and fractionated at intervals of two-centimeter depth on July 29, 1999. PAHs in colmn sediment samples were extracted in soxhlet extractor and were identified and quantified by GC-MS. PAHs compounds were analyzed and found to be 13 species. Total PAHs concentrations in the column sediments ranged from 275.04 to 2,838.64${\mu}g/kg$ dry wt. Naphthalene had the highest concentration in the range of 40.60 to 2,294.06${\mu}g/kg$ dry wt. and Anthracene had the lowest concentration in the range of 2.63 to 11.30${\mu}g/kg$ dry wt. The correlation coefficients between individual PAHs and total PAHs in the column sediments were relatively higher in the low molecular compounds such as Naphthalene, Acenaphthylene and Phenanthrene. The relationship between the P/A(Phenanthrene/Anthracene)ratio and F/P(Fluoranthene/Pyrene)ratio showed that P/A ratio was generally above 10 and F/P ratio was above 1 in all sediment samples. These data indicate that PAHs in the column sediments around Gwangyang bay seem to be of both pyrolytic and petrogenic origin The values of PAHs in the column sediments were lower than the biological effect guidelines.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.29 no.4
• /
• pp.477-487
• /
• 2019

Objectives: Firefighters are known to be exposed to a variety of toxic substances, but little information is available on the exposure profile of firefighting activities. The aims of this study were to conduct exposure monitoring of toxic chemicals at fire scenes, to compare the concentrations of respective chemicals among firefighting tasks, and to assess the main factors influencing the concentrations of chemicals. Methods: Researchers performed sampling at firefighting scenes during four weeks in 2013. At the scene, we collected samples based on firefighters' own activities and examined the situation and scale of the accident. Collected samples were classified into three categories, including fire extinguishing and overhaul, and were analyzed in the laboratory according to respective analysis methods. Results: A total of fourteen fire activity events were surveyed: five fire extinguishing, six overhaul, and three fire investigations. Although no substance exceeded the ACGIH TLV, PAHs were detected in every sample. Naphthalene ranged from 0.24 to 279.13 mg/㎥ (median 49.6 mg/㎥) and benzo(a)pyrene was detected in one overhaul case at 10.85 ㎍/㎥. Benzene (0.01-12.2 ppm) was detected in every task and exceeded the ACGIH TLV. No significant difference in concentrations between tasks was shown. Conclusions: These results indicate that all firefighting tasks generated various hazardous combustion products, including possible carcinogens.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.13 no.1 s.28
• /
• pp.9-20
• /
• 2007

PAHs(Polycyclic Aromatic Hydrocarbons) are widespread contaminants in the marine environment. They are of mainly anthropogenic origin from urban runoff, oil spill and combustion of fossil fuels. Some PAHs are potentially carcinogenic and mutagenic to aquatic organism The contamination of PAHs in the coastal environments has not been well known yet in Korea. This study was carried out to survey the contamination of PAHs in sediments around Gwangyang bay. The Yeosu petrochemical industrial complex, POSCO(Pohang steel company) and Gwangyang container harbor are located around the bay. PAHs in sediment samples were extracted in soxhlet extractor and were identified and quantified by GC-MS(Gas Chromatography-Mass Spectrometry) TOC(Total Organic carbon) and textural parameters in sediment samples were also analyzed 13 species of PAHs were detected at all of the surface sediments. Total PAHs concentrations in the surface sediments ranged from 171.40 to $1013.54{\mu}g/kg$ dry wt.. In most of the surface sediments, Naphthalene was the highest in the range of 14.08 to $691.39{\mu}g/kg$ dry wt. and Anthracene was the lowest in the range of 0.49 to $22.66{\mu}g/kg$ dry wt.. The correlation coefficients between individual PAHs and Total PAHs in the surface sediments were relatively higher in the low molecular compounds such as Naphthalene and Phenanthrene. In the relationship of the P/A(Phenanthrene/Anthracene) ratio and F/P(Fluoranthene/Pyrene) ratio, P/A ratio was generally above 10 and F/P ratio was shown to be above 1 in all sediment samples. These data indicate that PAHs in sediments around Gwangyang bay seem to be of both pyrolytic and petrogenic origin. Total PAHs in the surface sediments were correlated with TOC and textural parameters. The values of PAHs in the surface and core sediments were lower than the biological effect guidelines.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.2
• /
• pp.275-281
• /
• 2018

It is known that he pollutant emitted from the combustion process of marine fuel oil causes air pollution and harmful effects to the human body. Accordingly, IMO regulates pollutants emitted from ships. However, the regulation of Particulate Matter (PM) is still in the process of debate, so preemptive action is needed. Fundamental research on PM is essential. In this study, the Dimensionless Light Extinction Constant ($K_e$) of fuel oil used in marine diesel engines was measured and analyzed to construct the basic data of the PM generated from marine-based fuel oil. The fuel oil used in the land diesel engine was measured in the same way for character comparison. Both fuel oils differ in sulfur content and density. The $K_e$ was measured via the optical method using a 633 nm laser and was determined by using the volume fraction of PM collected by the gravimetric filter method. The $K_e$ of the PM discharged from marine fuel oil is 8.28, and the land fuel oil is 8.44. The $K_e$ of two fuel oils was similar within the measurement uncertainty range. However, it was found by comparison with the value obtained by the Rayleigh-Limit solution that the light scattering portion could be large. Also, it was found that light extinction characteristics could be different due to the relationship between light transmittance and collected mass.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.8
• /
• pp.554-563
• /
• 2013

The purpose of this study is to evaluate the possibility of nutrient release at up and downstream of Kangchun weir, upstream of Yuju and Ipo weir in Namhan River. For this survey, we measured basic characteristics of the sediments (water content, ignition loss, TOC, TP, SRP, TN, phosphorus fractionation) and conducted nutrients release experiments under both aerobic and anaerobic condition. The overlying water from the sediment-water column was analyzed for nutrients (i.e. TP, $PO_4$-P, TN, $NO_3$-N, $NH_3$-N) everyday for 18days. Result of soil texture experiment showed that sediments are Sand. SRP concentration before the release experiment was different with the value after the release experiment. According to this result, we can find that there were more activated release processes in anaerobic condition. $PO_4$-P increased from 1 to 8 days and remained at the maximum value (7~8 days) afterward. The rapidly increase of $PO_4$-P was observed from 1 to 2~3 days whereas the TP continuously increase from 1 to 18 days. The $PO_4$-P release rate calculated by up to 7~8 days data highly correlated with initial SRP concentration with $R^2$=0.8502. $NO_3$-N release rate appears constantly decreasing trend as -5.7~-3.08 $mg/m^2{\cdot}day$, otherwise the $NH_3$-N release rate, by-product of a organic matter decomposition using nitrate as electron acceptor, was 0.57~2.41 $mg/m^2{\cdot}day$. Substantial portion in TN can be induced by organic nitrogen which originated from the tributary passing through non-point pollutant source. Compared with other similar researches, phosphorus and nitrogen release rates obtained in this study can be considered as relatively low values. Since this study targeted the sediments accumulated by one time of flooding season, there are limitation to generalize theses results. Therefore, it is necessary to consistently monitor and investigate the accumulation of nutrients in the sediment for understanding the effect of weir construction on the overlying water quality.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.4
• /
• pp.315-327
• /
• 2007

This study investigated temporal and spatial variation of Pb and stable Pb isotopes accumulated in Ulleung Basin core sediments (4) using MC ICP/MS in order to identify the sources of anthropogenic Pb in the East/Japan Sea. Leached (1M HCl) Pb concentration and isotope ratios ($^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$) were nearly constant during 300 yrs past than 1930, but increased up to twice in concentration and as much as 3.41% (1.70%) after 2000. On the other hand, residual Pb concentrations were nearly constant for past 400 yrs. The accumulation rates of anthropogenic Pb in the basin area were in the range of $3.1-3.5mg/m^2/yr$, which were similar levels to total atmospheric Pb deposition fluxes from 1990s to the present. In the slope area, more increase of anthropogenic Pb accumulation than the levels expected from mass accumulation rate could be found after the middle of 1990s. From the detailed evaluation for the temporal and spatial variation of accumulation rate and isotope ratios of anthropogenic Pb, we proposed probable sources and pathways of anthropogenic Pb. Pb emmision by coal burning from the China and Korea initiated the accumulation of anthropogenic Pb in the sediments of East/Japan Sea from 1930s. The accumulation of Pb increased by the addition of anti-nocking agents from both countries untill the beginning of 1990s, but from the middle of 1990s to the present, the phase-out of gasoline additives and the rapid increase of coal burning from the China maintained the atmospheric Pb levels in the Ulleung basin nearly similar to before. However, the local sources within this basin might take an important role in the rapid increase of anthropogenic Pb accumulation in slope areas from the middle of 1990s.