• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.6
• /
• pp.696-701
• /
• 2018

The nitrogen oxides generated during combustion reactions have a great influence on the generation of acid rain and fine dust. As an NOx reduction method, exhaust gas recirculation combustion using Coanda nozzles capable of recirculating a large amount of exhaust gas with a small amount of air has recently been utilized. In this study, for the burner outlet with dual end opening, the use of a recirculation burner was investigated for the distribution of the pressure, streamline, temperature, combustion reaction rate and nitrogen oxides using computational fluid analysis. The gas mixed with the combustion air and the recirculated exhaust gas flow in the tangential direction of the circular cylinder burner, so that there is a region with low pressure in the vicinity of the fuel nozzle exit. As a result, a reverse flow is formed in the central portion of the burner near the center of the circular cylinder burner and the exhaust gas is discharged to the outside region of the circular cylinder burner. The combustion reaction occurs on the right side of the burner and the temperature and NOx distribution are relatively higher than those on the left side of the burner. It was found that the average NOx production decreased from an air flow ratio of 1.0 to 1.5. When the air flow ratio is 1.8, the NOx production increases abruptly. It is considered that the NOx production reaction increases exponentially with temperature when the air ratio is more than 1.5 and the NOx production reaction rate increases rapidly on the right-hand side of the burner.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.12
• /
• pp.1375-1381
• /
• 2011

Combustion processes in an optically-accessible single-cylinder heavy-duty diesel engine equipped with a highpressure common-rail injection system were investigated for JP-8 and diesel. Direct imaging and two-color thermometry were employed to verify the emission trend for both fuels. The combustion process was characterized by image analysis with focus on luminosity. The results of two-color thermometry were analyzed on the basis of the flame temperature and KL factor distribution. Analysis of the combustion process by direct imaging showed that the ignition delay was longer for JP-8 than for diesel, while the flame was extinguished rapidly. Analysis of the flame luminosity showed that the combustion intensity was higher for diesel and that the flame lasted for a longer duration in this case. Two-color thermometry results showed that the high-temperature region extended over a large area during JP-8 combustion, implying the formation of a large amount of $NO_x$. In addition, the KL factor showed low level over a large area and relatively homogeneous in the case of JP-8 combustion, which implied that less smoke was produced when using this fuel.

• Journal of Energy Engineering
• /
• v.17 no.4
• /
• pp.241-246
• /
• 2008

Increase of $CO_2$ by using fossil fuels makes mainly global warming and the international efforts to reduce the $CO_2$ emission is being promoted. Absorption process using aqueous alkanolamine solution to remove acid components in the mixed gases has been used commercially. This method was used to remove $CO_2$ in the flue gas in recent years. $CO_2$ Absorption characteristics of several aqueous alkanolamine solutions such as MEA, DEA and AMP was studied by measuring vapor-liquid-equilibrium(VLE) and absorption velocity in this study. VLE measuring equipment, shell and reactor type, was used to acquire VLE data, equilibrium $CO_2$ pressure(${P_{CO_2}}^*$) and time at each pulse gas input. We also acquired the $CO_2$ absorption velocity by measuring the time to arrive the VLE at $40{\sim}80^{\circ}C$ and first gas input. The $CO_2$ absorption capacity of MEA 10wt% solution was higher than two alkanolamine solutions at $40^{\circ}C$ and the equilibrium $CO_2$ loading was 0.5. Absorption capacity was excellent as follows; AMP>DEA>MEA. But absorption velocity was fast as follows; MEA>AMP>DEA. Though good absorbent was considered by many variables, absorption velocity and capacity was more important factor.

• Journal of Energy Engineering
• /
• v.28 no.4
• /
• pp.1-7
• /
• 2019

In response to the recent increase in demand for hydrogen stations, the Ministry of Trade and Industry has enacted and promulgated special notifications to enable the installation of hydrogen stations in the form of the combined complex in existing automotive fuel supply facilities such as LPG, CNG, and gas stations. Hydrogen multi energy filling stations haven't been operated yet in Korea till the establishment of special standards, so it is necessary create special standards by considering all Korean environmental characteristics such as four seasons and daily crossings. In this study, we collected and analyzed the charging data of Ulsan LPG-Hydrogen Multi Fueling Station installed for the first time in Korea. The data are hourly temperature and pressure data from compressors, storage vessels and dispensers. We used the data collected for a year, including the highest temperature and the lowest temperature in Ulsan to compare seasonal characteristics. As a result, it was found that the change of the outside temperature affects the initial temperature of the vehicle's container of the hydrogen car, which finally affects the charging time and the charging speed of the vehicle. There was no effect on vehicle containers because the limit temperature suggested by the Korean Hydrogen Station Standard(KGS FP217) and the US Filling Protocol(SAE J2601) was not exceeded.

• Polymer(Korea)
• /
• v.35 no.2
• /
• pp.106-112
• /
• 2011

Aromatic copolyamides were prepared and their applicability to proton exchange membrane was studied. The copolymers contain two segments; thermally stable and mechanically strong poly (p-phenylene terephthalamide) (PPTA), and easily processable and good film-forming polysulfone. For the copolymers, different ratios of amine-terminated sulfonated ether sulfone monomer, terephthaloyl chloride, and p-phenylene diamine were sequentially reacted. The obtained copolymers were mixed with trimethylolpropane triglycidyl ether (TMPTGE), thermally cured, and converted into proton exchange membranes for fuel cell application. The reactions at each step and the molecular characteristics of precursor copolymers were confirmed by $^1H$ NMR, FTIR, and titration. The performance of the membranes was measured in terms of water uptake and proton conductivity. The water uptake, ion exchange capacity (IEC), and proton conductivity of the membranes increased with the increase of sulfonated ether sulfone segment content. Membrane containing 60 mol% sulfonic acid sulfone segment showed 1.88 meq/g IEC value. Water uptake was limited less than 110 wt% and the highest proton conductivity was up to $7.4{\times}10^{-2}$ S/cm ($25^{\circ}C$, RH=100%).

• Resources Recycling
• /
• v.27 no.2
• /
• pp.55-62
• /
• 2018

This study aims to investigate the characteristics on bottom ash flotation using vegetable oils as a collector. The experiment of changing the kerosene dosage as a collector for the flotation of coal ashes, the recovery of unburned carbon and unburned carbon content were 80% and 63%, respectively, when the dosage of kerosene was 9 kg/ton. The experiment of using soybean oil as a collector to improve flotation efficiency, the recovery of unburned carbon and unburned carbon content increased to 95% and 68%, respectively, when the dosage of soybean oil was 9 kg/ton. The recovery of unburned carbon and unburned carbon content were 99% and 78%, respectively, when safflower oil containing more poly unsaturated fats with double bonds than soybean oil was 9 kg/ton. The calorific value of the unburned carbon was 5,803 cal/g, confirming that it was possible to be used as a fuel for thermal power plants. Lastly, using vegetable oil as a collector it showed higher recovery of unburned carbon and higher unburned carbon than kerosene, which was mineral oil. Moreover, oil containing a large amount of poly unsaturated fat with two or more double bonds was found to have higher unburned carbon than other vegetable oils; thus showing excellent adsorbability for unburned carbon.

• Clean Technology
• /
• v.24 no.1
• /
• pp.70-76
• /
• 2018

Pyrolysis of Saccharina japonica in an Auger reactor was conducted by varying the temperature and the auger speed and then physicochemical properties of the S. japonica-derived pyrolysis oil were analyzed. The maximum yield of S. japonica-derived pyrolysis oil (32 wt%) was obtained at a pyrolysis temperature of $412^{\circ}C$ and an auger speed of 20 rpm. Due to low carbon content and high oxygen content in the pyrolysis oil, the higher heating value of S. japonica-derived pyrolysis oil was $23.6MJ\;kg^{-1}$, which was about 60% that of conventional hydrocarbon fuels. By GC/MS analysis, 1,4-Anhydro-d-galactitol, dianhydromannitol, 1-hydroxy 2-propanone and isosorbide were identified as the main chemical compounds of S. japonica-derived pyrolysis oil. The bio-char has low higher heating value ($13.0MJ\;kg^{-1}$) due to low carbon content and high oxygen content and contains a large amount of inorganic components and sulfur.

• Journal of Korea Technology Innovation Society
• /
• v.11 no.2
• /
• pp.264-286
• /
• 2008

In 2006, the share of energy in Korea amounted to 28% from the total import, 97% from overseas dependency, and 83% for the national Greenhouse Gas (GHG) emission in 2004. Thus, from the aspects of economical and environmental policies, an energy analysis is very important, for the industry to cope with the imminent pressure for climate change. However, the estimation of GHG gas emissions due to an energy use is still done in a primitive way, whereby each industry's usage is multiplied by coefficients recommended from international organizations in Korea. At this level, it is impossible to formulate the prevailing logic and policies in face of a new paradigm that seeks to force participation of developing countries through so called post-Kyoto Protocol. In this study, a hybrid energy input-output (E-IO) analysis is conducted on the basis of the input-output(IO) table of 2000 issued by the Bank of Korea in 2003. Furthermore, according to economic sectors, emission of the GHG relative to an energy use is characterized. The analysis is accomplished from four points of view as follows: 1) estimating the GHG emission intensity by 96 sectors, 2) measuring the contribution ratio to GHG emissions by 14 energy sources, 3) calculating the emission factor of 3 GHG compounds, and 4) estimating the total amount of national GHG emission. The total amount estimated in this study is compared with a national official statistical number. The approach could be an appropriate model for the recently spreading concept of a Life Cycle Analysis as it analyzes not only a direct GHG emission from a direct energy use but also an associated emission from an indirect use. We expect this model can provide a form for the basis of a future GHG reduction policy making.

• Resources Recycling
• /
• v.21 no.2
• /
• pp.34-40
• /
• 2012

$Pt_{10}$/C, $Pt_9Mn_1$/C, $Pt_7Mn_3$/C electrocatalysts for Polymer Electrolyte Membrane Fuel Cells(PEMFCs) were synthesized by reduction with HCHO and their activity as a oxygen reduction reaction(ORR) was examined at half cell. The electrochemical oxygen reduction reaction(ORR) was studied by using a glaasy carbon electrode through cyclic voltammetric curves(CV) in a 1 M $H_2SO_4$ solution. The ORR activities of $Pt_9Mn_1$/C were higher than $Pt_{10}$/C, $Pt_7Mn_3$/C. Also potential-current curves of $Pt_9Mn_1$/C at 0.9, 0.8, 0.7, 0.6V for 5minutes respectively were higher than $Pt_{10}$/C, $Pt_7Mn_3$/C. Physical characterization was made by using x-ray diffraction(XRD) and transmission electron microscope(TEM). The TEM images of $Pt_9Mn_1$/C, $Pt_{10}$/C catalysts showed homogenous particle distribution with particle size of about 2.7 nm, 3 nm respectively and then the XRD results showed that the crystalline structure of the synthesized catalysts are seen FCC structure.

• Journal of Climate Change Research
• /
• v.4 no.4
• /
• pp.349-358
• /
• 2013

In this study, the newest technology available to reduce GHG emissions, which can be applicable in energy industries of the future that has large reduction obligations by energy target management and large intensity of GHG emissions, has been investigated by searching the technical characteristics of each technology. The newest technology to reduce GHG emissions in the field of power generation and energy can be mainly classified into the improvement of efficiency, CCS, and gas combined-cycle technology. In order to improve the reliability of the GHG emission factor obtained from the investigation process, it has been compared to the technology-specific GHG emission factor derived from the estimated amount of emissions. Then the GHG abatement measures, using the derived estimation of factor, by using the newest technology to reduce GHG emissions have been predicted. As a result, the GHG reduction rate by technology of CCS development has been expected to be the largest more than 30%, and the abatement rate by technology of coal gasified fuel cell and pressurized fluidized-bed thermal power generation has been showed more than 20%. If the effective introduction of the newest technology and the study of its characteristics is continued, and properly applied for future GHG emissions, it can be prospected that the national GHG reduction targets can be achieved in cost-efficient way.