• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.487-494
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• 1996

Simultaneous effects of $C_2H_4$ injection and heterogeneous chemical reactions on non-thermal plasma process to remove $SO_2$ and NOx from flue gas were investigated in the present experimental study. The present results showed that 40% of the electrical power can be reduced in $C_2H_4$ injection and heterogeneous chemical reaction are simultaneously included in the non-thermal plasma precess. As an effort to apply the non-thermal plasma technique to practical flue gas treatment system, a wire-plate type reactor which has technically similar geometry of industrial electrostatic precipitators is used instead of other types of reactors, such as wire-cylinder, packed-bed and surface discharge which are inappropriate to industrial application. In the present study, the photo pictures of positive streamer corona taken by ICCD camera, voltage and current oscillograms, and design criteria of a wire-plate type reactor are also shown, which are needed for industrial application of the non-thermal plasma process.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.217-222
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• 2015

There has been increased amount of atmospheric pollutants including NOx and SOx which cause acid rain and photochemical smog as a result of increased use of fossil fuels. In order to reduce the amount of pollutants produced by fossil fuel, wet scrubber system is introduced in this experiment. Wet scrubber system is applied to a diesel engine (3,298 cc) and the amount of smoke is measured before and after the application in terms of aspect ratio, filling rate, and flow rate. The result showed a lot of smoke reduction when wet scrubber system was applied, and also the aspect ratios and water spray flow rate were the important factors to improve smoke reduction.

• Journal of Industrial Technology
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• v.18
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• pp.249-258
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• 1998

In this paper, we investigated the post-combustion removal of nitrogen oxide($NO_x$) and sulfur oxide($SO_x$) which is based on the gas to particle conversion process by the pulsed corona discharge. Under normal pressure, the pulsed corona discharge produces the energetic free electrons which dissociate gas molecules to form the active radicals. These radicals cause the chemical reactions that convert $SO_x$ and $NO_x$ into acid mists and these mists react with $NH_3$ to form solid particles. Those particles can be removed from the gas stream by conventional devices such as electrostatic precipitator or bag filter. The reactor geometry was coaxial with an inner wire discharge electrode and an outer ground electrode wrapped on a glass tube. The simulated flue gas with $SO_x$ and $NO_x$ was used in the experiment. The corona discharge reactor was more efficient in removing $SO_x$ and $NO_x$ by adding $NH_3$ and $H_2O$ in the gas stream. We also measured the removal efficiency of $SO_x$ and $NO_x$ in a cylinder type corona discharge reactor and obtained more than 90 % of removal efficiency in these experimental conditions. The effects of process variables such as the inlet concentrations of $SO_x$, $NH_3$ and $H_2O$, residence time, pulse frequencies and applied voltages were investigated.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1061-1068
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• 2012

These days, world wide interest about global warming and environmental pollution and exhausting fossil fuel which have been main energy source in all around the world. So many country have tried to find out the solution by investing new & renewable and clean energy. Therefore LNG have been widely used as a substitution of fossil fuel and clean energy that emits less pollutant like SOx, NOx. Therefore LNG consumption has been quickly raised and LNG carriers have been getting larger for decades. In this study, high power fiber laser was used for welding of stainless steel for LNG carrier to increase its productivity. Used material was STS316L which has low carbon less than 0.03% and its thickness was 8 mm. We carried out bead, lap and butt welding by using the fiber laser which has maximum power up to 5kW. As a result, we could find out that lap and butt joint was possible at welding speed of 2.0m/min and 3.0m/min respectively.

• Resources Recycling
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• v.20 no.5
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• pp.52-57
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• 2011

This study was conducted to examine the possibilities to utilize the mixture of domestic and organic wastes from B-city as a fuel. All types of mixing ratio for uncarried waste, sludge cake, and food waste were found 10 generate heating value with 6,000 kcal/kg, and in case of sludge cake the concentration of toxic substance produced was found to be decreased as air-fuel ratio and temperature were increased. It was noted that toxic gases such as CO, NOx, and SOx were observed below concentration of emission standard, and temperature inside the incinerator was stabilized at 2 of air-fuel ratio and 800$^{\circ}C$. It was observed that a heating value of 6000 kcal/kg generated using RDF(Refuse Derived Fuel) was appropriate to utilize a fuel if a complete combustion was attained.

• Journal of Environmental Policy
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• v.12 no.2
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• pp.59-86
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• 2013

We analyzed the correlation among the GHG (Greenhouse Gas) emission, energy consumption and economic growth for the 6 specific regions in Korea by using Panel approaches with the test of the EKC hypothesis. We also analyzed the effects of environmental regulation on GHG and economic growth. The results show that by testing of the EKC (Environmental Kuznets Curve) hypothesis model,the effects of the environmental regulation and the structure of industries on GHC emission have a significant result on the regional analysis for SOx. For the NOx and TSP, only TK region passed the turning point of the EKC among the 6 specific regions. And, for the Co, the Central, Honam and the PUKN region passed the turning point of the EKC. This is because GHG emissions by the environment regulation had a weak path effect and also regional industry structures had a weak relation with regional GHG emissions.

• Journal of Navigation and Port Research
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• v.40 no.4
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• pp.173-181
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• 2016

From 2016, controls on reduction of NOx and SOx emissions from the vessels that are operated in the emission control area were tightened. The selectivity catalytic reduction system of the denitrification equipment which NOx among the above controlled materials is very effective and used commercially very much. But it has the disadvantage that CSR is activated at high temperatures. Therefore, the SCR and SCR activation instrument that can react even at low temperatures by using micro-nano bubbles so that the above problems can be minimized were developed. And the computational fluid dynamics technique was used by ANSYS-CFX package to prepare the plan that improves the SCR system's efficiency. Simulation for the viscous flow analysis of the SCR system was executed by applying the Navier-Stokes equation to it as a governing equation. For the SCR system's shape, 3D modeling was done by using CATIA V5. SCR jet nozzle's position was checked by changing it to the intervals of 1/3, 1/2, and 2/3 from the inlet of the vent pipe to compare the SCR system's efficiency. And the number of nozzles was compared and analyzed by simulating 4, 6, and 8 holes to check an effect of the number on the SCR system's efficiency. The simulation result has found that the closer nozzles are to the inlet of the vent pipe and the more nozzles are, the more efficiency is improved.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.1-10
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• 2022

Exhaust gases emitted from internal combustion engines contain nitrogen oxides (NOx) and sulfur oxides (SOx), which are major air pollutants causing acid rain, respiratory diseases, and photochemical smog. As a countermeasure, scrubber systems are being studied extensively. In this study, the pressure drop characteristics were analyzed by changing the exhaust gas inflow velocity using a scrubber for a 700 kW engine as a model. In addition, the fluid flow inside the scrubber and the behavioral characteristics of the droplets were studied using CFD, and the design compatibility of the cleaning device was verified. Flow analysis was performed using inertial and viscous resistances by applying porous media to the complex shape of the scrubber. The speed of the exhaust passing through the outlet nozzle from the inlet was determined through the droplet behavior analysis by spraying, and the flow characteristics for the pressure drop were studied. In addition, it was confirmed through computational analysis whether there was a stagnation section in the exhaust gas flow in the scrubber or the sprayed droplets were in good contact with the exhaust gas.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.3
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• pp.398-415
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• 2010

The purpose of this paper is to grasp levels of cost burden in pollution treatment by measuring efficiencies and shadow prices by pollutants in Korean cities. The efficiencies and shadow prices of pollutants will be compared for cities divided by Seoul metropolitan area and non-Seoul metropolitan area. Annual shadow prices of NOx, SOx, and PM10 emissions in the cities of Seoul metropolitan area are 0.846, 0.318, 0.816, respectively for 1999-2005. The annual shadow prices in the cities of Non-Seoul metropolitan area are 0.848, 0.272, and 0.789, respectively over the same periods. The shadow prices of SOx showed similar levels between two areas but those of NOx and PM10 of cities in Seoul metropolitan area were higher. NOx emission quantities of both areas have similar increasing patterns because the NOx has mainly increased with augmentation of transportation regardless of Seoul metropolitan and non-Seoul metropolitan areas. It seems that the reason the shadow prices of two pollutants for the cities of Seoul metropolitan area are higher, is because environmental regulation is stronger in the cities of Seoul metropolitan area, the cities of Seoul metropolitan relatively show higher quantities of pollution reduction under given desirable outputs, and generally have industrial sectors with small pollution emission. In the future we need to reduce pollutants in the various respects such as adjustment of overall industry structure, energy consumption pattern, and reviews of arrangement of living space for the cities located on the downward-sloping segment of production frontier.

• Journal of the Korean Chemical Society
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• v.64 no.6
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• pp.334-344
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• 2020

The adsorption of various atmospheric harmful gases (COx, NOx, SOx) on graphene-like Germanene 2D sheet was theoretically investigated using density functional theory(DFT) method. The structures were fully optimized at the B3LYP/cc-pvDZ and CAM-B3LYP/cc-pvDZ levels of theory and confirmed to be a local minimum by the calculation of the harmonic vibrational frequencies. The adsorptions of gases on the Germanene sheet were predicted to be a physisorption process for CO, CO2, NO, and SO2 gases but to be a chemisorption process for NO2, SO, and SO2 gases.