• 한국수소및신에너지학회논문집
• /
• 제25권6호
• /
• pp.561-569
• /
• 2014

Ceria ($CeO_2$) was used to increase the durability of the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance. The sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) to improve electrochemical characteristics. After sulfonation reaction, the organic-inorganic blended composite membranes were prepared by means of sol-gel casting method with loading the highly dispersed $CeO_2$ and Cs-substituted molybdophosphoric acid (Cs-MoPA) with cross-linking agent (tetrapropyl orthosilicate). Consequently, the composite membrane CL-SPEEK/Silane 4wt%/Cs-MoPA/Ceria(1%) showed the improved characteristics such as 82% of water content, 0.11136 S/cm of proton conductivity at $80^{\circ}C$, 55.50 MPa of tensile strength and 4.37% of breeding out of MoPA.

• 한국수소및신에너지학회논문집
• /
• 제25권6호
• /
• pp.636-642
• /
• 2014

As environment problem became a worldwide issue, countries are tightening regulations regarding greenhouse gas reduction and improvement of air pollution problems. With these circumstances, one of the renewable energies produced from biomass is getting attention. Bio-ethanol, which is applicable to SI engine, showed a positive effect on the PFI (Port Fuel Injection) type. However, Ethanol has a problem in homogeneous mixture formation because it has high latent heat of vaporization characteristics and in the GDI (Gasoline Direct Injection) type, mixture formation is required quickly after fuel injection. Particularly, South Korea is one of the countries with great temperature variation among seasons. With this reason, South Korea supply fuel additive for smooth engine operation during winter. Therefore, experimental study and investigation about application possibility of blending fuel is necessary. This paper demonstrates the spray characteristics by using the CVC direct injection and setting the bio-ethanol blending fuel temperature close to the temperature during each seasons: -7, 25, $35^{\circ}C$. The diameter and the width of the CVC are 86mm and 39mm. High-pressure fuel supply system was used for target injection pressure. High-speed camera was used for spray visualization. The experiment was conducted by setting the injection pressure and ambient pressure according to each temperature of bio-ethanol blending fuel as a parameter. The result of spray visualization experiment demonstrates that as the temperature of the fuel is lower, the atomization quality is lower, and this increase spray penetration and make mixture formation difficult. Injection strategy according to fuel temperature and bio-ethanol blending rate is needed for improving characteristics.

• 한국가스학회지
• /
• 제17권1호
• /
• pp.1-6
• /
• 2013

$NO_x$ 배출허용기준이 강화되는 배출가스 규제에 대응하기 위한 대안으로서 제시되는 천연가스-수소 혼합연료 (HCNG)는 수소의 빠른 화염속도와 넓은 가연범위를 이용하여 후처리 장치 없이 규제치를 만족할 수 있어 디젤엔진에 비해 저공해성이나 가격경쟁력 측면에서 유리한 장점이 있다. 열효율 측면에서도 우수성을 인정받는 HCNG 연료는 수소 혼합율은 물론 운전영역별 운전전략에 따라 연소특성이 달라진다. 본 연구에서는 대형 천연가스 엔진에 수소혼합율 30%의 HCNG 연료를 적용하여 운전영역별 안정적인 연소특성 및 배출가스 특성을 살펴봄으로써 상용화 가능성과 운전전략을 포함한 기술 개발방향에 대해 검토하고자 하였다.

• 한국수소및신에너지학회논문집
• /
• 제26권3호
• /
• pp.212-220
• /
• 2015

The engineering plastic of sulfonated polyether ether ketone (SPEEK) as a polymer matrix has been developed in this lab to replace Nafion, solid polymer electrolytes of perfluorosulfonic acid membrane which has several flaws such as high cost, and limited operational temperature above $80^{\circ}C$. The SPEEK was prepared in the sulfonation reaction of polyether ether ketone (PEEK). The organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted tungstosilicic acid (Cs-TSiA) with cross-linking agent contents of 0.01 mL. In conclusion, CL-SPEEK/Cs-TSiA/ceria 1% membrane showed the optimum results such as 0.1882 S/cm of proton conductivity at $80^{\circ}C$, and 99.61 MPa of tensile strength which were better than Nafion 117 membrane.

• 한국수소및신에너지학회논문집
• /
• 제29권1호
• /
• pp.81-89
• /
• 2018

Fuel blend technique is one of the most effective way of using biomass to replace the coal. Many studies on combustion characteristics with coal and biomass blends have been conducted. In this study, char reactivity and emission characteristics of coal (Suek) and biomass (EFB) blends has been investigated by TGA and DTF to evaluate the applicability of the pre-treated (torrefaction, ash removal technology) EFB to pulverized coal boiler. In all blending cases, char reactivity improved as the blending ratio increases (10, 20, and 30%), especially torrefied EFB blended at 30%. Also, unburned carbon decreased as the blending ratio increases in all types of EFB. NOx emission showed the increase and decrease characteristics according to the content of fuel-N of raw EFB and torrefied EFB. But the amount of NOx emission at ashless EFB blends is greater than that of Suek despite of lower fuel-N. It indicated that co-firing effect of using the pretreatment biomass fuel is relatively better than those of the untreated biomass fuel about char reactivity and emission characteristics.

• 한국수소및신에너지학회논문집
• /
• 제25권1호
• /
• pp.1-10
• /
• 2014

Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance and to increase the duration of the membrane. In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) and the organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted phophomolybdic acid(Cs-MoPA) with cross-linking agent contents of 0.01mL. In conclusion, CL-SPEEK/$Cs_{(2.5)}$-MoPA/ceria(1%) membrane showed the optimum results such as 0.1095S/cm of proton conductivity at $80^{\circ}C$, 2.906meq./g-dry-membrane of ion exchange capacity and mechanical characteristics, and 49.73MPa of tensile strength which were better than Nafion 117 membrane.

• 한국수소및신에너지학회논문집
• /
• 제29권5호
• /
• pp.523-529
• /
• 2018

Two liquids which are generally used as fuels of rockets are mixed and their mixing process is quantitatively investigated by the use of particle image velocimetry (PIV). As working fluids for the liquid mixing, Dimethylfuran (DMF) and JetA1 oils have been used. Since the specific gravity of DMF is larger than that of JetA1 oil, the DMF oil has been set at the lower part of the JetA1 oil. For better visualization of the mixing process, Rhodamin B powder has been blended into the DMF oil. An agitator having 3 blades has been used for mixing the two liquids. For quantitative visualization, a LCD monitor has been used as a light source. A color camera, camcoder, has been used for recording the mixing process. The images captured by the camcoder have been digitized into three color components, R, G, and B. The color intensities of R, G, and B have been used as the inputs of the neural network of which hidden layer has 20 neurons. Color-to-concentration calibration has been performed before commencing the main experiments. Once this calibration is completed, the temporal changes of the concentration of the DMF has been quantitatively analyzed by using the constructed measurement system.

• 한국수소및신에너지학회논문집
• /
• 제23권5호
• /
• pp.437-447
• /
• 2012

Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance and to increase the duration of the membrane. In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) and the organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted tungstophosphoric acid (Cs-TPA) with cross-linking agent contents of 0.01 mL. In conclusion, CL-SPEEK/Cs-TPA/ceria (1%) membrane showed the optimum results such as 0.130 S/cm of proton conductivity at $80^{\circ}C$, 2.324 meq./g-dry-membrane of ion exchange capacity and mechanical characteristics, and 65.03 MPa of tensile strength which were better than Nafion 117 membrane.

• 한국수소및신에너지학회논문집
• /
• 제30권6호
• /
• pp.567-577
• /
• 2019

Due to the depletion of fossil fuels and environmental pollution, demand for alternative energy is gradually increasing. Among the various methods, a method to convert biomass into alternative fuel has been proposed. The bio-fuel obtained from biomass through pyrolysis process is called pyrolysis oil (PO) or bio-oil. Because PO is difficult to use directly in conventional engines due to its poor fuel properties, various methods have been proposed to upgrade pyrolysis-oil. The simplest approach is to mix it with conventional fossil fuels. However, due to their different polarity of PO and fossil fuel, direct mixing is impossible. To resolve this problem, emulsification of two fuels with a proper surfactant was proposed, but it costs additional time and cost. Alternatively, the use of alcohol fuels as an organic solvent significantly improve the fuel properties such as fuel stability, calorific value and viscosity. In this study, blends of diesel, n-butanol, and coffee ground pyrolysis oil (CGPO) which is one of the promising PO, was applied to diesel generator. Combustion and emissions characteristics of blended fuels were investigated under the entire load range. Experimental results show that ignition delay is similar to that of diesel at high load. Although, hydrocarbon and carbon monoxide emissions are comparable to diesel, significant reduction of nitrogen oxides and particulate matter emissions were observed.

• 공업화학
• /
• 제9권2호
• /
• pp.185-192
• /
• 1998

네 종류의 폴리아믹산(PPA)은 서로 다른 구조의 디아민들인 3,3'-diaminodiphenyl sulfone(3,3'-$DDSO_2$), 4,4'-diarrinodiphenyl sulfone(4,4'-$DDSO_2$), 4,4'-methylene dianiline(4,4'-MDA) 및 4,4'-oxydianiline(4,4'-ODA)와 디안하이드라이드인 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA)를 용매인 DMAc를 이용하여 합성되었다. 이들의 폴리아믹산(PAA)을 이용하여 poly[2,2-(m-phenylene)-5,5'-bibenzimidazole](PBI)와 용액 블렌딩하여 Blend-I, II, III, 그리고 IV로 칭하였으며, 이에 대한 시료를 필름이나 분말로 제조한 PBI/PAA 시스템을 예상된 $T_g$보다 높은 온도에서 열경화시켜 PBI/PI 블렌드로 전환시킨후 PI 합성시 사용된 디아민의 분자구조 변화에 따른 블렌드의 상용성과 그 상호작용의 상대적인 세기를 살폈다. 이로부터 본 연구에서 이용된 네 개의 블렌드들은 상용성을 보였으며, 이들 상용성을 가져다주는 상호작용의 세기는 Blend-III와 Blend-IV가 Blend-I와 Blend-II보다 큼을 보였다. 이와 같이 블렌드에 사용된 PI의 구조변화에 따라 상호작용이 다른 것은 PI합성시에 사용된 디아민의 구조에서 페닐링 사이에 존재하는 linkage인 O나 $CH_2$보다는 $SO_2$가 존재할 때 블렌드를 이루는 두 고분자사이의 상호작용인 수소결합력을 약화시키는 spacer로 작용하였다고 판단된다.