• Korean Chemical Engineering Research
• /
• v.45 no.5
• /
• pp.455-459
• /
• 2007

Plasma catalytic methane conversion was carried out in the presence of sol-gel derived $Pt/TiO_2$ catalysts within a dielectric-barrier discharge (DBD) reactor. Plasma-assisted reduction (PAR) was applied to reduce the prepared $Pt/TiO_2$ catalysts in DBD reactor, and prepared catalysts were successively reduced by PAR within 20 min irrespective of the Pt loading and the calcination temperature. The highest methane conversion was 40% when 3 wt% $Pt/TiO_2$ and 5 wt% $Pt/TiO_2$ catalysts were used after calcination at $600^{\circ}C$. The selectivities of light alkanes ($C_2H_6$, $C_3H_8$, $C_4H_{10}$) were highly increased when $Pt/TiO_2$ catalysts were used in DBD reactor.

• Journal of Environmental Health Sciences
• /
• v.46 no.2
• /
• pp.159-169
• /
• 2020

Objectives: The purpose of this study was to investigate changes among the nine kinds of reduction chemical substances in Korea over the period of 2008-2017. We will define basic data for improving the management methods for reducing chemical substances. Methods: A survey of hazardous pollutant emissions for 2008-2017 was conducted through the pollutant Release and Transfer Register homepage. Nine kinds of designated reduction chemical substances (Benzene, Vinyl chloride, Trichloro ethylene, 1,3-butadiene, Dichloro methane, Tetrachloro ethylene, N,N-dimethylformamide, Acrylo nitrile, and Chloroform) provided the study subjects. The emission of hazardous chemicals and health effects used the National Health Statistics and Integrated Chemicals Information System (ICIS) as a reference. Results: Hazardous pollutant emissions increased by 1.2 times over the past decade, and nine types of reduction chemical substances increased by 1.6 times. By region, the emissions of reduction chemical substances over the last 10 years were in the order of Chungbuk, Gyeonggi, and Gyeongbuk. Emissions of Dichloro methane was the highest in Chungbuk and Gyeongbuk. N,N-dimethylformamide was the highest in Gyeonggi. Carcinogen pollutant emissions showed a tendency to increase continuously. In addition, group 1 carcinogen emissions showed a tendency to decrease. Conclusion: In the last decade, the amount of hazardous chemical emissions has been continuously increasing. Hazardous chemical emissions require facility improvement for continuous emissions reduction. More research on reduction of emissions is needed.

• Journal of the Korean Society of Industry Convergence
• /
• v.11 no.1
• /
• pp.5-10
• /
• 2008

A flame speed of methane mixture of water vapor and air have been measured to study the process of flame propagation using schlieren photographs. The quantity of water vapor contained were changed 5% and 10% of total mixture, and equivalence ratio of mixture between 0.8 and 1.2 were tested under the ambient temperature 323K and 373K. The results showed that the burning velocity was decreased by increasing the water vapor contents due to the interruption of flame development. And, the reduction rate of burning velocity was smaller by increasing the water contents under the same ambient temperature. The effects of ambient temperature on burning velocity was decreased by increasing the water vapor contents.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.5
• /
• pp.715-718
• /
• 2013

Density of catalytic organisms can determine the biodegradation capacity and specific biodegradation rate (SBR). A new index, biodegradation capacity utilization (BCU, %), was developed for estimating the extent of actual biodegradation of a gas compound over the full capacity. Three methanotrophic cultures were serially diluted (1-1/25), and methane SBR and BCU were measured. Consistently, biomass reduction increased the SBR and decreased the BCU. Linearity (p < 0.05, r > 0.97) between the BCU and cell density indicated the reflection of biodegradation capacity by BCU. Therefore, BCU is indicative of whether the density of catalytic organisms is pertinent for SBR evaluation of low-soluble gaseous compounds.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.63-66
• /
• 2007

Reformers which produce hydrogen from natural gas are essential for the operation of residential PEM fuel cells. For this purpose, steam-methane reforming reactions with Ni catalysts is primarily utilized. Commercial Ni catalysts are generally made to have porous pellet shapes in which Ni catalyst particles are uniformly dispersed over Alumina support structures. This study numerically investigates the reduction of catalyst effectiveness due to the mass transport resistances posed by porous structures of spherical catalyst pellets. The multi-component diffusion through porous media and the accurate kinetics of reforming reaction is fully considered in the numerical model. The preliminary results on the variation of the effectiveness factor according to different operation conditions are presented, which is planned to be used to develop correlations in future studies.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.5
• /
• pp.453-458
• /
• 2017

A study on the modeling of the methane Chemical Looping Reforming system was carried out. It is aimed to predict the temperature and concentration behavior of the product through modeling of oxygen carrier fixed bed reactors composed of multiple stacks. In order to design the reaction system, first of all, the flow rate of the hydrogen to be produced was calculated. The flow rate ratio of the oxidation/reduction reactor was calculated considering the heat of reaction between adjacent reactors. Finally, in this paper, kinetic model including empirical coefficients was suggested.

• Journal of Biosystems Engineering
• /
• v.36 no.5
• /
• pp.342-347
• /
• 2011

The effect of SNC(silver nano colloid) on the emission reduction of odors such as ammonia ($NH_3$), hydrogen sulfide ($H_2S$), and methane ($CH_4$) from swine excreta was studied. Silver has been used as an universal antibiotic substance and can reduce the emission of some gases by sterilizing action. Therefore, an apparatus which produces SNC was developed and was conducted its performance test. Also, the SNC made by the apparatus was applied to swine excreta sampled from a piggery in oder to find the effect on the reduction of odor emission. An electrolysis apparatus was developed to produce SNC and its capacity was 0.024 ppm/$hr{\cdot}L$. The effects of SNC on the reduction of odor emission from swine excreta were tested for bad smell gases of ammonia ($NH_3$), hydrogen sulfide ($H_2S$) and methane ($CH_4$). For ammonia gas, factorial experiments were conducted to find the effects of concentration and application rate of SNC. The test results for the different concentrations of 20 ppm, 50 ppm, and 100 ppm showed that the more concentration of SNC was increased, the more emission reduction of ammonia gas increased. From the test results about the effect of application rate, the more SNC was applied, the more emission reduction of $NH_3$ increased. In order to reduce the concentration of $NH_3$ below 5 ppm, SNC of 50 ppm is recommended to be applied at an interval of 6 hours, and is mixed with swine excreta in the volumetric ratio of 4:1. For hydrogen sulfide gas, the concentration was decreased as time went by and was reduced rapidly in the first stage of the tests for all applied concentrations of SNC (20 ppm, 50 ppm, and 100 ppm). Especially, when 100 ml of SNC with 100 ppm was applied, emission of hydrogen sulfide gas was reduced rapidly during early 4 hours after the application of SNC. And, concentration of hydrogen sulfide gas was maintained below 20 ppm after 12 hours. For methane gas, t-test showed that there was no significance on the effect of its application for all applied concentrations of SNC. Therefore, it was concluded that the application of SNC on swine excreta had no effect on the emission reduction of $CH_4$.

• KSBB Journal
• /
• v.8 no.5
• /
• pp.438-445
• /
• 1993

Raw cow manure was treated by a 4-step integrated system with phase separation anaerobic digestion and algal culture. When the first methane fermentation was performed by the effluent from the acid fermenter with retention time of 4 days, the elrerage blogas production rate was 977m1/1 culture/day Gas productivity compared to conventional single-stage anaerobic digestion increased up to 31.4%. As the 2nd methane fermenter was fed by the effluent from the first methane fermenter with 4 days of retention time, average amount of 428m1/1 culture/day of biogas was produced. The reduction rate of COD in the effluent from the acid fermenter, the 1st and the 2nd methane fermenter were 71.8%, 42.6% and 24.0% respectively. Finally, we examined algal treatment process for the effluent from the 2nd methane fermenter. A semi-continuous culture of Chlorella sp. PSH3 was conducted by feeding the effluent with retention time of 10days. In this process, the production rate of algal biomass and COD reduction rate were averaged 1.8g/1 culture/day(2.8$\times$106 cells/ml) and 73%, respectively. Through the 4-setp treatments, the total chemical oxygen demand was reduced from 51,300ppm to 85ppm. Therefore, the reduction rate of total chemical oxygen demand reached about 99.8%. The results indicate that the integrated system could be applicable for treatment of organic wastes, concurrently producing biogas and algal biomass.

• Journal of Energy Engineering
• /
• v.25 no.3
• /
• pp.104-113
• /
• 2016

This study analyzes correlation between methane gas production and injection of food waste water to motivate to expand renewable energy as a way of GHG (Green House Gas) mitigation to achieve the national GHG target proposed for the climate agreement in Paris last year. Pretreatment of food waste water was processed with pH 6 at $35^{\circ}C$ and used the fixed-bed upflow type reactor with the porous media. As a result of operation of pilot-scaled bioreactor with food waste water, the methane gas production was 6 times higher than the methane gas production of control group with rain water. The average production of methane was $56{\ell}/day/m^3$ which is possible to produce $20m^3$ of methane in $1m^3$ of landfill. As a way of energy source, when it is applied to the landfill over $250,000m^3$, it is also able to achieve financial feasibility along with GHG reduction effect. GHG reductions of $250,000m^3$ scale landfill were assessed by registered CDM project and the annual amount of reductions was 40,000~50,000 $tCO_2e$.

• Ocean and Polar Research
• /
• v.36 no.1
• /
• pp.25-37
• /
• 2014

To understand the degradation processes of organic matter related to sulfate reduction by Sulfate Reduction Bacteria (SRB) in the tidal flat sediments of Hwang-do and Sogeun-ri, Tae-an Peninsula in Chungnam-do, biogeochemical characteristics were analyzed and highlighted using specific microbial biomarkers. The organic geochemical parameters (TOC, ${\delta}^{13}C_{org}$, C/N ratio, long-chain-n-alkane) indicate that most of the organic matter has been derived from marine phytoplankton and bacteria in the fine-grained sediment of Sogeun-ri, although terrestrial plant components have occasionally been incorporated to a significant degree in the coarse-grained sediment of Hwang-do. The concentration of sulfate in pore water is a constant tendency with regard to depth profile, while methane concentration appears to be slightly different with regard to depth profile at the two sites. Especially, the sum of bacteria fatty acid (a-C15:0 + i-C15:0 + C16:1w5) confirms that the these concentrations in Sogeun-ri are related to the degradation of Benzene, Toluene, Ethylbenzene and Xylene (BTEX) compounds from the crude oil retained in the sediments as a result of the Hebei Spirit oil-spill accident in 2007. The methane-related microbial communities as shown by lipid biomarkers (crocetane, PMI) are larger in some sedimentary sections of Hwang-do than in the Sogeunri tidal flat. These findings suggest that methane production by microbiological processes is clearly governed by SRB activity along the vertical succession in organic-enriched tidal flats.