• Journal of the Korean Institute of Gas
• /
• v.25 no.4
• /
• pp.36-42
• /
• 2021

When the landfill gas generated at the landfill site is released into the atmosphere, methane gas with a high global warming potential is emitted, which adversely affects climate change. When methane contained in landfill gas is used as fuel for internal combustion engines and burned to generate electricity, it is emitted into the atmosphere in the form of carbon dioxide, which can contribute to lowering the global warming potential. Therefore, in order to use the landfill gas as fuel for power generation using an internal combustion engine, it is important to increase the thermal efficiency of the engine. Thus, it is necessary to use a fuel supply system in which gas is injected using an electronically controlled injector at an intake port for each cylinder rather than a fuel supply technology using the conventional mixer technology. In order to use the electronically controlled gas injection method, it is important to accurately measure the mass flow rate according to the conditions of using landfill gas. For this, a study was conducted to measure the injection amount and calculate them in order for the intake port gas injection of landfill gas.

• The Korean Journal of Quaternary Research
• /
• v.20 no.1 s.26
• /
• pp.51-66
• /
• 2006

The climate of the last glacial maximum (LGM) in northeast Asia is simulated with an atmospheric general circulation model of NCAR CCM3 at spectral truncation of T170, corresponding to a grid cell size of roughly 75 km. Modern climate is simulated by a prescribed sea surface temperature and sea ice provided from NCAR, and contemporary atmospheric CO2, topography, and orbital parameters, while LGM simulation was forced with the reconstructed CLIMAP sea surface temperatures, sea ice distribution, ice sheet topography, reduced $CO_2$, and orbital parameters. Under LGM conditions, surface temperature is markedly reduced in winter by more than $18^{\circ}C$ in the Korean west sea and continental margin of the Korean east sea, where the ocean exposed to land in the LGM, whereas in these areas surface temperature is warmer than present in summer by up to $2^{\circ}C$. This is due to the difference in heat capacity between ocean and land. Overall, in the LGM surface is cooled by $4{\sim}6^{\circ}C$ in northeast Asia land and by $7.1^{\circ}C$ in the entire area. An analysis of surface heat fluxes show that the surface cooling is due to the increase in outgoing longwave radiation associated with the reduced $CO_2$ concentration. The reduction in surface temperature leads to a weakening of the hydrological cycle. In winter, precipitation decreases largely in the southeastern part of Asia by about $1{\sim}4\;mm/day$, while in summer a larger reduction is found over China. Overall, annual-mean precipitation decreases by about 50% in the LGM. In northeast Asia, evaporation is also overall reduced in the LGM, but the reduction of precipitation is larger, eventually leading to a drier climate. The drier LGM climate simulated in this study is consistent with proxy evidence compiled in other areas. Overall, the high-resolution model captures the climate features reasonably well under global domain.

• Journal of Bio-Environment Control
• /
• v.18 no.3
• /
• pp.291-296
• /
• 2009

This study was conducted to compare the storability of 6 chicory cultivars for producing chicon; 'Vintor', 'Focus', 'Metafora', 'Kibora', 'Nobus', and 'Redoria Red' grown in 2 regions: Chuncheon (plain region) and Pyeongchang (high land region). Chicons were produced from chicory roots that grown for 120days and then stored for over 120days at $2^{\circ}C$ and 90% of RH conditions. To produce chicon, chicory root was forced at $18^{\circ}C$ for 22days with suppling the nutrient solution ($KNO_30.54g{\cdot}L^{-1}$, $Ca(NO_3)_2\;1.02g{\cdot}L^{-1}$, $MgSO_4\;0.36g{\cdot}L^{-1}$, $KH_2PO_4\;0.21g{\cdot}L^{-1}$, $K_2SO_4\;0.10g{\cdot}L^{-1}$, pH 7.0). Chicons produced from 6 different chicory cultivars packed with $25{\mu}m$ ceramic film and stored for 25days at $8^{\circ}C$. The fresh weight of chicon in MAP was maintained to 99.5% of pre-storage weight. The fresh weight of 'Redoria Red' was lowest in all cultivars, and that of Chuncheon region cultivated treatment was lower than Pyeongchang treatment. The $CO_2$ and $O_2$ concentration in chicon MAP were 2% and $10{\sim}17%$. There were not significantly different among cultivars and between regions, although 'Redoria Red' cultivar showed highest $CO_2$ and lowest $O_2$ concentrations. The ethylene concentration in chicon MAP was $1.0{\mu}{\iota}{\cdot}{\iota}^{-1}$ and also didn't show any significant difference among all treatments. Chicon detoriorated visual quality with appearing russet spotting that result from ethylene gas. The visual quality of 'Redoria Red' cultivar decreased faster than the other cultivars. 'Metafora', 'Focus', and 'Kibora' maintained higher firmness of their leaf than the others, and the firmness was higher grown in Pyeongchang region cultivated treatments than in Chuncheon region.

• Korean Chemical Engineering Research
• /
• v.52 no.5
• /
• pp.657-666
• /
• 2014

Coal gasification technology is considered as next generation clean coal technology even though it uses coal as fuel which releases huge amount of greenhouse gas because it has many advantages for carbon capture. Coal or pet-coke slurry gasification is very attractive technology at present and in the future because of its low construction cost and flexibility of slurry feeding system in spite of lower efficiency compared to dry feeding technology. In this study, we carried out gasification experiment using bituminous coal slurry sample by integrating coal slurry feeding facility and slurry burner into existing dry feeding compact gasifier. Especially, our experiment was conducted under fairly lower operation temperature than that of existing entrained-bed gasifier, resulting in partial slagging operation mode in which only part of ash was converted to slag and the rest of ash was released as fly ash. Carbon conversion rate was calculated from data analysis of collected slag and ash, and then cold gas efficiency, which is the most important indicator of gasifier performance, was estimated by carbon mass balance method. Fairly high performance considering pilot-scale experiment, 98.5% of carbon conversion and 60.4% of cold gas efficiency, was achieved. In addition, soundness of experimental result was verified from the comparison with chemical equilibrium composition and energy balance calculations.

• Journal of Plant Biotechnology
• /
• v.40 no.2
• /
• pp.79-87
• /
• 2013

The aim of this study was to establish plant regeneration from leaf explants of Sedum tosaense Makino, which is globally rare and endangered species. The leaf explants of S. tosaense were cultured on the MS medium supplemented with different concentration of BA and NAA for callus induction. Callus induction was showed the highest (100%) on MS medium containing $2.0mg{\cdot}L^{-1}$ BA and $1.0mg{\cdot}L^{-1}$ NAA. The highest number of shoots were regenerated when callus were cultured on MS medium containing $2.0mg{\cdot}L^{-1}$ BA and $1.0mg{\cdot}L^{-1}$ NAA for 5 weeks. The axillary bud were cultured on the MS media supplemented with combination of BA and NAA for in vitro propagation. The highest number of adventitious shoot (7.9 per explants) formed at $1.0mg{\cdot}L^{-1}$ NAA and $2.0mg{\cdot}L^{-1}$ BA. For rooting, MS medium supplemented with or without $2.0g{\cdot}L^{-1}$ activated charcoal was tested. The optimal results were observed using MS medium supplemented with $2.0g{\cdot}L^{-1}$ activated charcoal, on which 85.7 (No. of root), 4.6 cm (length of root). 1,200 ppm $CO_2$ and 350 ppm $CO_2$ were supplied for make certain the effects of $CO_2$ on pre-acclimatization by photoautotrophic culture. 1,200 ppm $CO_2$ treatment was established higher than 350 ppm $CO_2$ treatment. Soil acclimatization of in vitro plantlets was the best in mixture soil consisted of peat moss and perlite with 100% survival rate and they showed the maximum growth.

• Journal of Bio-Environment Control
• /
• v.28 no.4
• /
• pp.293-301
• /
• 2019

The experiment was conducted to determine the performance of DME combustion gas when used as a fuel for DME burner for raising temperature and $CO_2$ concentration in greenhouse and also to examine its effects on chlorophyll content, and fresh and dry weight of lettuce and Chinese cabbage. DME-1 and DME-2 treatments consisted of average DME flow quantity in duct were $17.4m^3min^{-1}$ and $10.2m^3min^{-1}$ respectively to greenhouse-1 and greenhouse-2 and no DME gas was supplied to greenhouse-3 which was left as control (DME-3). DME supply times were $0.5hr\;day^{-1}$, $1hr\;day^{-1}$, $1:30hrs\;day^{-1}$ and $2hrs\;day^{-1}$ on week 1, 2, 3, and 4 respectively. Chlorophyll content and fresh and dry weight of lettuce and Chinese cabbage were measured for each treatment and analyzed through analysis of variance with a significance level of P<0.05. The result of the study showed that $CO_2$ concentration increased up to 265% and 174% and the level of temperature elevated $4.8^{\circ}C$ and $3.1^{\circ}C$ in greenhouse-1 and 2, respectively as compared to greenhouse-3 due to application of DME combustion gas. Although, the same crop management practices were provided in greenhouse-1, 2 and 3 at a same rate, the highest change (p<0.05) of chlorophyll content, fresh weight and dry weight were found from the DME-1 treatment, followed by DME-2. As a result, DME combustion gas that raised the level of temperature and $CO_2$ concentration in the greenhouse-1 and greenhouse-2, might have an effect on growth of lettuce and Chinese cabbage. At end of experiment, the highest fresh and dry weight of lettuce and Chinese cabbage were measured in greenhouse-1 and followed by greenhouse-2. Similarly chlorophyll content of greenhouse-1 and greenhouse-2 were more compared to greenhouse-3. In general, DME was not producing any harmful gas during its combustion period, therefore it can be used as an alternative to conventional fuel such as diesel and liquefied petroleum gas (LPG) for both heating and $CO_2$ supply in winter season. Moreover, endorsed quantify of DME combustion gas for a specified crop can be applied to greenhouse to improve the plant growth and enhance yield.

• Horticultural Science & Technology
• /
• v.29 no.3
• /
• pp.211-216
• /
• 2011

This study was carried out to clarify precise $CO_2$ demands of paprika plants (Capsicum annumm L.) by measuring photosynthesis rates of the leaves in high, low positions, and the $CO_2$ consumption of a whole plant in a large sealed chamber. A photosynthesis measuring system (LI-6400) was used to measure the photosynthetic rates of the leaves located in different positions. A large sealed chamber that can control inside environmental factors was developed for measuring $CO_2$ consumption by a whole paprika plant. With increase of radiation, photosynthetic rates of the leaves in higher position became larger than those in lower position. The $CO_2$ consumption by the plant was estimated by using decrement of $CO_2$ concentration from initial level of 1500 ${\mu}mol{\cdot}mol^{-1}$ in the chamber with increase of integrated radiation. A regression model for estimating $CO_2$ consumption by the plant (leaf area = 7,533.4 $cm^2$) was expressed with integrated radiation (x) and was suggested as $y=-0.06234+3.671^*x/(2.589+x)$ ($R^2=0.9966^{***}$). The photosynthetic rate of the whole plant measured in the chamber was 3.4 ${\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ under 300 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ light intensity, which is in-between photosynthetic rates of the leaves in high and low positions. For this reason, some differences between required and supplied $CO_2$ amounts in greenhouses might occur when depending too much on photosynthetic rates of leaves. Therefore, we can estimate more accurately $CO_2$ amount required in commercial greenhouses by using $CO_2$ consumption model of a whole plant obtained in this study in addition to leaf photosynthetic rate.

• Journal of Bio-Environment Control
• /
• v.20 no.4
• /
• pp.406-411
• /
• 2011

This study was conducted to find out the effect of cut-off period (0 hour, 3 hours, 6 hours, 12 hours, and 24 hours) to supply nutrient solution for chicon forcing at that was predrying treatment on the storability of chicon. The cut-off treatment increased dry matter rate, respiration rate, and ethylene production rate. The dry matter rate of chicon increased, as the cut-off period increased, but the respiration rate and ethylene production rate of chicon was highest in 12 hours and 6 hours cut-off treatment, respectively, and then their rates decreased, as the cut-off period prolonged. The weight loss at cut-off 6 hours treatment was lower than other treatments during $10^{\circ}C$ storage temperature. The cut-off 6 hours treatment showed higher carbon dioxide and oxygen concentration in 10,000 cc/$m^2$/day/atm oxygen permeability film package during storage period than control and showed a little predrying effect but was not statistically significant. At $4^{th}$ day, the ethylene concentration reached higher than other storage day and after that decreased but was not statistically significant. The quality of chicon for 3 hours, 6 hours, 24 hours cut-off treatments on storability showed higher than other treatments, accordingly. The 6 hours cut-off treatment showed the inhibited effect of the degree of browning of chicon cutting plane. The effect of 6 hours cut-off treatment on storability of chicon showed proper predrying effect, reduced moisture loss and browning inhibition apparently during $10^{\circ}C$ storage.

• Plant Journal
• /
• v.18 no.4
• /
• pp.58-65
• /
• 2023

In this study, to increase the methane content of biogas supplied from Nanji Water Regeneration Center and to purify impurities, a three-stage membrane purification process was designed and installed to demonstrate operation. The methane concentration of biomethane produced in the 2 Nm3/h purification process was set to three cases: 95%, 96.5%, and 98%, and the membrane area ratio of the membrane was 1:1, 1:2, 1:1:1, The optimum conditions for the membrane area of the separator were derived by changing to five of 1:2:1 and 1:2:2. 3 stage separation membrane process of 30 Nm3/h was installed to reflect the optimum condition of 2 Nm3/h, and biomethane production of 98% or more of methane concentration was demonstrated. As a result of the operation of the 2 Nm³/h refining device, the methane recovery rate at the 98% methane concentration was 95.6% when the membrane area ratio was 1:1 as the result of the two-stage operation of the separator, and the recovery rate of methane at 1:2 was increased to 96.8%. The methane recovery rate of the membrane three-stage operation was highest at 96.8% when the membrane area ratio was operated at 1:2:1. The carbon dioxide removal rate was 16.4 to 96.4% and the 2:2 to 95.7% film area ratio in the two-step process. In the three-step process, the film area ratio was 1:2:1 to 95.4%, and the two-step process showed higher results than the three-step process. In the 30 Nm3/h scale biogas purification demonstration operation, the methane concentration after purification was 98%, the recovery rate of methane was 97.1%, the removal rate of carbon dioxide was 95.7%, and hydrogen sulfide, the cause of corrosion, was not detected, and the membrane area ratio was 1:2:1 demonstration operation, biomethane production with a methane concentration of 98% or higher was possible.

• Environmental and Resource Economics Review
• /
• v.32 no.1
• /
• pp.47-75
• /
• 2023

Compared to the EU, which legislates the Carbon Border Adjustment System (CBAM), the United States' carbon border adjustment policy movement is still relatively slow. Recently, however, a related bill has been proposed in the United States, and research institutes have been presenting research results on how to introduce an upstream carbon tax rather than an emission trading system and carry out carbon border adjustment based on it. Therefore, in this study, we looked at the economic and environmental effects of introducing this type of upstream carbon tax and carbon border adjustment in Korea. If an upstream carbon tax of KRW 30,000 per ton of CO₂ is applied to the net supply of domestic fossil energy, the expected carbon tax revenue is approximately KRW 22.9961 trillion, equivalent to about 5.7% of the total revenue of the Korean government of KRW 402 trillion in 2019. In addition, the carbon dioxide content of the steel sector, calculated based on the energy supply and demand status of the steel sector, which emits the most greenhouse gas emissions in Korea and has a considerable amount of overseas exports, was 106.22 million tons of CO₂. On the other hand, assuming that the upstream carbon tax of 30,000 won per ton of CO₂ embodied is directly passed on to the production cost of the steel sector, the carbon tax burden in the steel sector is estimated to reach approximately KRW 3.1865 trillion. Even after deducting KRW 1.1599 trillion in export refunds estimated by using the share of exports of steel products, the net carbon tax burden on steel products for domestic demand amounts to KRW 2.0266 trillion, which is analyzed to act as a factor in increasing the price of steel products.