• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.171-178
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• 2011

During the last decades, global warming from the increased amount of greenhouse gases, mainly carbon dioxide has become a major political and scientific issue. Burning fossil fuels (natural gas, coal and oil) releases $CO_2$, which is also a major cause of global warming. Among the clean environment, wood pellets are considered as promising renewable fossil fuels because of clean burning characteristics, reduction of particulate and NOx emission from combustion. In Korea, more than 50% pellets have to be imported every year because of shortage of feedstocks. On the other hand, about 80% of wood pulps are greatly dependent upon overseas products due to limited forest resources. Under this situation, this study explored how efficiently we have to use forest biomass instead of total dependence on wood as raw materials for pellets.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.406-412
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• 2007

An experimental study on the design of a catalytic combustor for 1.6 kW MCFC system has been performed. The roles of the catalytic combustor are to completely burn anode off-gas and to supply sufficient $CO_2$ to cathode channels. In order to avoid hot spot or fuel slippage, flow uniformity at the catalyst inlet was achieved by installing two crossing perforated plates between the catalyst and the mixing chamber with minimal pressure drop. A Pd/Ce/Ni-$Al_2O_3$ catalyst was used for complete combustion of the off-gas at GHSV=36,000.

• Journal of Environmental Science International
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• v.22 no.3
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• pp.269-279
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• 2013

In this paper, an environmental assessment was carried out on the whole process of industrial business activities to establish a basic plan for climate change mitigation and energy independency. The whole process was divided into each discharge process in terms of water, air, solid waste, green house gases and refractory organic compounds. The flowcharts and basic unit of process were analysed for three years (2008-2010), being utilized as basic information for the life cycle assessment. It was found that the unit loading for the whole process significantly depends on changes in the operation rate change and highly concentrated wastewater inflow. About 35% of solid waste production was reduced by improving the incineration method with co-combustion in coal boiler, generating about 57% of electricity used for the whole process, and consequently reducing the energy costs. As the eco-efficiency index was found to be more than 1, compared to the previous years, it can be said that improvement in general has taken place.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.17-25
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• 2009

The precise calculation of gas absorption coefficient in the radiative transfer equation is very important to the prediction of radiative heat transfer induced from liquid engine plume in view of base insulation design. For this purpose, the WNB model for gas absorption coefficient is described with the selection of important parameters and then the calculated results are compared with those of SNB model for validation. Total emissivity, narrow band averaged intensity and total intensity are calculated and compared to the results of SNB model. As results, the total emissivity and the total intensity are well matched within 3.1% and roughly 5 % error, respectively. Moreover, the gas modeling database is constructed with estimation of the combustion gas composition of $CO_2$ and $H_2O$ for liquid engine plume.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.3
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• pp.373-377
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• 2009

It is well known that SOx and NOx concentration has a considerable influence on the $N_2O$ emission of the greenhouse gas properties. The quantity of SOx generated during combustion, on fuel specific basis, is directly related to the sulfur content of the fuel oil. However, restricting the fuel oil sulfur content is only a partial response to limiting the overall quantity of SOx emissions, as there remains no over control on the fuel oil consumption other than the commercial pressure which have always directed the attention. This study was carried out as a new basic experiment method of emission control, manly targeted to the vessel. In the experiment, where the scrubbing was achieved through spray tower with high alkaline water made from the electrolysis of seawater, the combined action was to neutralize the exhaust gases (SOx, PM, CO etc.), dilute it, and wash it out. The results showed that SOx reduction of around 95 percent or over could be achieved when using in the high alkaline water, and also leaded to a reduction in the stability of the each pollutant components including the PM (Particulate Matter). The results suggest that the seawater electrolysis method has a very effective reduction of emissions without heavy cost, or catalysts particularly on board.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.589-594
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• 2001

In this study, the effects of the number and the presentational type of anomalous data on students'cognitive conflict and conceptual change in studying 'conservation of mass before and after combustion'were investigated. The subjects were 128 eighth graders in a co-ed middle school. A preconception test, a test of response to anomalous data, and a conception test were administered. Four types of anomalous data varying the number (one/two) and the presentational type (text/text+figure) were presented. The results indicated that students with two anomalous data showed more cognitive conflicts than those with one. However, no significant differences in the degree of cognitive conflict were found by the presentational types of anomalous data. The ANOVA results indicated that there were no significant differences by the characteristics of anomalous data in the conception test scores.

• Journal of ILASS-Korea
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• v.19 no.1
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• pp.25-32
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• 2014

For reduction of $CO_2$ emission emitted from combustion engine, the developed nations have been focused on R&D of hybrid electric vehicle. Further more, many automobile companies are researching on various techniques related to engine used in HEV to enhance fuel economy. One of key techniques is miller cycle that control a valve timing to reduce compression stroke for saving energy and increase expansion stroke for high power. In this study, it was investigated the in-cylinder flow characteristics of miller cycle with variable intake valve timing by using the ANSYS simulation code. For simulation, the key analytic parameter defined as intake valve closing timing and cam profile. As main results, it was shown that LIVC cause a lower pressure inside cylinder and had better control turbulence intensity.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.308-317
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• 2015

To investigate the effect of microstructure on the formation of the desorption peak, the volumetric thermal analysis technique (VTA) was applied to the Mg-13.5 wt% Ni hydride system. The sample made by the HCS (hydriding combustion synthesis) process had two kinds of Mg microstructures. Linear heating was started with various constant heating rates. Only one peak was appeared in the case of the small initial hydrogen wt% (0.83 wt%). Yet, two peaks were appeared with increasing initial hydrogen wt% (1.85 and 3.73 wt%) when only Mg was hydrogenated. The first peak was formed through the evolution of hydrogen from $MgH_2$, made by eutectic Mg. The second peak was formed through the evolution of hydrogen from $MgH_2$, made by primary Mg. Therefore, this result shows that the microstructure also has a considerable effect on forming the desorption peak. We have also derived the hydrogen desorption equations by VTA to get apparent activation energy when the rate-controlling step for the desorption of the hydrided system is the diffusion of hydrogen through the ${\alpha}$ phase and the chemical reaction ${\beta}{\rightarrow}{\alpha}$.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1257-1262
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• 2014

The variances of atomization characteristics with the misalignment of injectors defined as the fraction of skewness for various angles of impingement and pressure conditions were studied using the doublet impinging injectors with a like-on-like arrangement. Water was used as simulant and the spray characteristics along with the changes in the skewness were analyzed using the methods of spray image photography. Experiment was carried for the impinging nozzles of orifice diameter of 1.2 mm within Reynolds numbers ranging from $9{\times}10^3-4.5{\times}10^4$ and the fraction of skewness considered for the experiment ranges from 0.0 to 0.9 at ambient temperature condition. Flat sheet with a distinct rim produced perpendicular to the plane of impinging jets goes ondisappear and sheet appears comparatively shorterwith the increase in fraction of skewness resulting the atomization of fluid droplet very close to impingement point with decrease in breakup length and increase in spray angle up to certain extent. The maximum allowable skewness was found as the result. The skewness up to the certain extent can be considered as the parameter to control the atomization characteristics of simulant inside the combustion chamberproviding the high economic performance of fuel and time.

• The Journal of the Acoustical Society of Korea
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• v.11 no.4
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• pp.31-35
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• 1992

Cavity resonances are caused by combustion such as the rapid of pressure rise that occurs from knock in high power gasoline engines. These resonances generally occur at frequencies greater than 5KHz. Analysis of these resonances is important for knock control system design in high power gasoline engines. In this paper, in order to design knock control system for the high power gasoline engine, knock phenomena that occur in chamber were analized theoretically and resonance frequencies of knock signals were predicted. Also, experiments were performed using Soupe x-engine and non-resonance type knock sensor of Bosch co. in Germany. In the result, good agreement was obtained between theoretical prediction and experimental observation.