• Transactions of the Korean hydrogen and new energy society
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• v.29 no.2
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• pp.139-147
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• 2018

Korea Electric Power Research Institute (KEPCO RI) had developed molten carbonate fuel cell (MCFC) system since 1993. Finally, KEPCO RI developed and operated a 125 kW MCFC system in 2010. To make MCFC system compact, it is indispensable to install an ejector in this system where the anode off gas, the cathode off gas, and fresh air are mixed before flowing to the catalytic burner. KEPCO RI had developed various ejectors for MCFC system since 2006. The 125 kW MCFC system built with the developed ejector was operated successfully in Boryeong Thermal Power Plant in 2010. This 125 kW MCFC ejector was designed on the basis of the experimental results of 5 kW and 75 kW MCFC ejectors. The main goal of ejector design in our MCFC system is to maintain the entrainment ratio and the pressure between fuel cell stack and catalytic burner within the operating range. In this paper, the design results of the ejector are presented based on the 125 kW MCFC system operating conditions. In addition, a designed ejector was manufactured and installed in the MCFC system. As the fuel cell is under load operation, the pressure surrounding the ejector was measured to ensure that the fuel cell system is operating smoothly.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.965-970
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• 2008

The separation of sulfone components using light cycle oil(LCO) after oxidation was carried out by solvent extraction method using various polar solvents such as water, n-methyl-2-pyrrolidone(NMP), dimethyl sulfoxide, ethyl acetate, acetonitrile, dimethyl formamide, and methyl alcohol. It was found that phase separation between LCO layer and solvent occurred under mixed solvent adding a proper amount of water. The mixture solvent of NMP and water was a promising extraction solvent due to the selective removal and high distribution coefficient of sulfone component in LCO. 99.5% over of sulfur contents in LCO can be removed by 4 stages equilibrium extraction.

• Journal of the Korean Society of Combustion
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• v.17 no.4
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• pp.11-20
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• 2012

The Blow-off characteristics of LPG/air lean pre-mixed flames were experimentally investigated using a double and a multiple concentric coflow burners. Experiments were conducted to understand the effects of recirculation motion, thermal interaction between flames, and stratified flame configuration. Here, the stratified premixed flame is a "new concept" of a flame that sequentially contains fuel rich, stoichiometric, and fuel lean reaction zones in a flame. The blow-off from a lean premixed flame was significantly suppressed with recirculation motion. The recirculation motion by itself, however, was not sufficient to prevent the blow-off when the equivalence ratio became low. The existence of a inner premixed flame could also help to prevent the blow-off of lean premixed flame; however, the blow-off suppression effect was rather diminished by weakened recirculation motion with the presence of inner flame. The inner flame could be separated from an outer flame on a multiple concentric coflow burner, causing recirculation motion as well as thermal interaction between flames to become effective; therefore, the blow-off was further suppressed. The lean premixed flame could be stabilized with a fuel rich premixed flames that was produced with the supply of fuel through an inner nozzle. The penetration of lean premixed gas from outside into the fuel stream produced a lifted rich premixed flame. Chemiluminescence images of OH, CH, and $C_2$ radicals confirmed the structure of a stratified premixed flame. The stable premixed flames could be obtained at the very fuel lean condition by applying the stratified premixed flame concept.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.28-33
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• 2015

In this study, a dual fuel engine fueled with natural gas and diesel was tested to investigate the effects of heating value variation of CNG fuel. CNG substitution rate which is defined as the ratio of CNG and diesel supplied in a heating value basis was fixed at 80%. The higher heating value was varied from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$ by mixing nitrogen gas with pure CNG and diesel fuel was injected at a fixed injection timing. The engine test results showed that thermal efficiency and power output were decreased as the heating value of mixed CNG fuel was decreased. And the peak cylinder pressure was also decreased but the ignition delay time and the combustion duration and timing were almost same.

• Journal of Power System Engineering
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• v.22 no.6
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• pp.67-73
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• 2018

Gasoline that meets the quality standards is distributed in Korea. However, consumers who use toluene or solvent mixed with gasoline have appeared due to rising crude oil prices and for the purpose of tax evasion. Gasoline quality standard is enacted by the domestic and international research reference. A wrong fuel can influence automobile performance or environmental issue. Thus, empirical data from this issue is necessary. Therefore, this research observed catalyst influence by gasoline property change and inspect influence of environment. In this study, fuel property evaluation, lean-burn evaluation, and real vehicle exhaust emission test were performed. In the result of fuel property, the fuel "A" was measured to be up to 27% less octane than the normal gasoline and the distillation property was measured 24% higher than normal gasoline. In the test result of single cylinder engine lean-burn test, the fuels "A" and "B" show torque value 20% less than the normal gasoline. As a result of vehicle test using the catalyst, the fuel "A" was increased more than the normal gasoline with 83% THC, 1,806% CO and 128% NOx, and the fuel "B" was increased more than normal gasoline with 1.6% THC, 391% CO and 142% NOx.

• Clean Technology
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• v.18 no.4
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• pp.426-431
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• 2012

Carbon-rich coal can be utilized as a fuel for direct carbon fuel cell (DCFC). However, left-behind ash after the electrochemical oxidation may hinder the electrochemical reactions. In this study, we produced ash-free coal (AFC) by thermal extraction and then tested it as a fuel for DCFC. DCFC was built based on solid oxide electrolyte and the electrochemical performance of AFC mixed with $K_2CO_3$ was compared with AFC only. Significantly enhanced power density was found by catalytic steam gasification of AFC. However, an increase of the power density by catalytic pyrolysis was negligible. This result indicated that a catalyst activated the steam gasification reactions, producing much more $H_2$ and thus increasing the power density, compared to AFC only. Results of a quantitative analysis showed much improved kinetics in AFC with $K_2CO_3$ in agreement with DCFC results. A secondary phase of potassium on yttria-stabilized zirconia (YSZ) surface was observed after the cell operation. This probably caused poor long-term behavior of AFC with $K_2CO_3$. A thin YSZ (30 ${\mu}m$ thick) was found to be higher in the power density than 0.9 mm of YSZ.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3367-3378
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• 2021

The design phase and safety assessment of Generation IV liquid metal-cooled fast reactors calls for the improvement of fuel pin performance codes, in particular the enhancement of their predictive capabilities towards uranium-plutonium mixed oxide fuels and stainless-steel cladding under irradiation in fast reactor environments. To this end, the current capabilities of fuel performance codes must be critically assessed against experimental data from available irradiation experiments. This work is devoted to the assessment of three European fuel performance codes, namely GERMINAL, MACROS and TRANSURANUS, against the irradiation of two fuel pins selected from the SUPERFACT-1 experimental campaign. The pins are characterized by a low enrichment (~ 2 wt.%) of minor actinides (neptunium and americium) in the fuel, and by plutonium content and cladding material in line with design choices envisaged for liquid metal-cooled Generation IV reactor fuels. The predictions of the codes are compared to several experimental measurements, allowing the identification of the current code capabilities in predicting fuel restructuring, cladding deformation, redistribution of actinides and volatile fission products. The integral assessment against experimental data is complemented by a code-to-code benchmark focused on the evolution of quantities of engineering interest over time. The benchmark analysis points out the differences in the code predictions of fuel central temperature, fuel-cladding gap width, cladding outer radius, pin internal pressure and fission gas release and suggests potential modelling development paths towards an improved description of the fuel pin behaviour in fast reactor irradiation conditions.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.938-943
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• 2007

Anaerobic degradation of petroleum hydrocarbons in a soil artificially contaminated with 10,000 mg/kg soil of diesel fuel was tested by adding an anaerobic sludge taken from a sludge digestion tank. Treatments of soil(50 g) with 15 mL/kg soil and 30 mL/kg soil of the digestion sludge(2,000 mg/L of vss(volatile suspended solids)) showed 37.2% and 58.0% of total petroleum hydrocarbons(TPH) removal during 90 days incubation, respectively. In evaluation of several anaerobic conditions including nitrate reducing, sulfate reducing, methanogenic, and mixed electron accepters condition, treatments with the digested sludge showed significant degradation of diesel fuel under all anaerobic conditions compare to a control treatment of soil without the sludge and a treatment of autoclaved soil treatment with autoclaved digestion sludge. The rate of diesel fuel degradation was the highest in the treatment with the sludge and mixed electron accepters (75% removal of TPH) for 120 days incubation followed in order by sulfate reducing, nitrate reducing, methanogenic condition as 67%, 53%, 43%, respectively. However, the removal rate of non-biodegradable isoprenoid was the highest in the sulfate reducing condition. These results suggest that anaerobic degradation of diesel fuel in soil with digested sludge is effective for practical remediation of soil contaminated with petroleum hydrocarbons.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.559-567
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• 2008

SAPO-34 is a well-known catalyst for methanol to olefins (MTO) process, but is rapidly deactivated by coke formation. It is necessary to improve the catalyst lifetime of SAPO-34 for MTO process. In the present work, SAPO-34 catalysts were synthesized with a variety of structure directing agent, and the physicochemical properties of the catalysts were examined by $N_2$-isotherm, XRD, SEM, and $NH_3$-TPD. It was found that mixed structure directing agents, especially DEA and TEAOH, gave well developed SAPO-34 crystal structure and reduced the crystal size and moderated acidity of SAPO-34 under the same synthetic conditions as that of various structure directing agents. Also, we could find that SAPO-34 catalyst prepared by mixed templates of DEA and TEAOH had the superior catalytic activity and the longer lifetime in MTO reaction.

• Resources Recycling
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• v.30 no.1
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• pp.53-59
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• 2021

Waste vinyl generated from household waste has been used as a solid refuse fuel (SRF) due to the presence of impurities such as soil, metal, and glass; however, the amount of SRF used has been decreasing owing to recent environmental problems, thereby necessitating the need for recycling. In this study, the mixed recycled raw material produced from household waste vinyl and polyethylene (PE) single recycled raw material produced from agricultural waste vinyl were examined. Raw material analysis revealed that waste vinyl was mainly composed of polyethylene, and approximately 2% of ash remained in the mixed recycled raw material, whereas no ash was found in the PE single recycled raw material. In addition, the analysis of tensile strength according to the mixing ratio of the two recycled raw materials revealed that the highest tensile strength was approximately 16 MPa under the heat treatment temperature of 200 ℃, compression pressure of 30 MPa, and a mixing ratio of 3:7 (mixed:PE single). In addition, the highest bending strength was approximately 39 MPa under the heat treatment temperature of 200 ℃, compression pressure of 30 MPa, and a mixing ratio of 3:7 (mixed:PE single). Therefore, the possibility of recycling waste vinyl was suggested by investigating the change in strength characteristics according to the mixing ratio of the recycled raw materials.