• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.50-57
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• 2015

Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of a by-products such as fly ash and ground granulated blast-furnace slag to partially replace the cement in concrete are gathering momentum. Many researchs on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the sources of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effect reduction of $CO_2$ gas. In this study, we investigated the influence of the fluidity, air content and compressive strength of mortar on alkaline activator in order to develop cementless fly ash and ground granulated blast-furnace slag based alkali-activated mortar with superplasticizer. In view of the results, we found out that Pn of fluidity and compressive strength is the best in four type of superplasticizer, and PNS of powder type of fluidity is better than that of liquid type in the case of AA.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.143-143
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• 2010

GTL(Gas-to-Liquids)공정 중 합성가스 제조공정(Reforming Process)인 ATR(Auto-Thermal Reforming), SCR(Steam Carbon Reforming), POx(Partial Oxidation)의 시뮬레이션 연구를 수행하였다. Reforming 공정에서 생산된 합성가스는 GTL 합성유 제조공정인 FT(Fischer-Thropsch) 반응기로 주입되며, 합성유 생산에 최적의 효율을 보이는 H2/CO 비(합성가스에 포함된 반응물비)는 2.0으로 알려져 있다. FT공정은 합성가스를 원료로 고온 및 고압 반응을 거쳐 GTL 공정의 최종 생산품인 FT합성유를 제조하는 공정이다. 본 연구에서는 FT공정 효율 극대화를 위해 reforming 공정에서 생성되는 합성가스 내 H2/CO의 비를 2로 수렴토록 모사조건을 설정하였으며, 상기 조건을 만족하는 reforming 공정들의 운전 온도 및 feed 조성을 분석하고 비교하고자 한다. 현재 GTL 플랜트관련 산업계에 적용 혹은 주 연구대상인 reforming 공정으로는 ATR, SCR, POx 공정이 있다. ATR 공정은 $850{\sim}1100^{\circ}C$에서 메탄, 스팀 및 산소를 원료로 활용하여 H2 및 CO를 생산하는 공정으로 발열/흡열 반응이 상존하여 에너지 비용이 낮지만 공정구조 상 열회수설비 및 ASU(Air Separation Unit)이 필요하기에 CAPEX(초기설비 설치비용)가 높은 편이다. SCR공정은 CH4, Steam 및 CO2를 연료로 하기에 이산화탄소가 일정부분 포함된 가스전에도 적용이 가능하나 공정 운전 중 지속적으로 외부에서 열을 공급해야 하기에 에너지 투입비용이 높은편이며, 탄소침적의 문제가 있어 대용량 플랜트에는 적합하지 않다. POx공정은 약 $1,500^{\circ}C$의 고온에서 CH4가 O2에 의해 부분 산화되는 방식으로 촉매가 필요없어 설비비가 타 공정에 비해 저렴하나 생산가스의 H2/CO비가 다소 낮아 전체적인 GTL 공정효율이 저하되는 단점이 있다. 상기 세 공정은 GTL 산업계에서 실증 및 효율증대를 위해 주로 연구되는 공정이기에 본 연구의 분석대상으로 설정하였다. 본 연구에서는 상용공정모사기인 Aspen Plus를 활용하여 reforming 공정별로 FT합성공정의 최적 조건(H2/CO=2)을 만족하는 합성가스 생산조건 분석 및 비교를 수행할 예정이다. 운전조건인 공정 운전온도 및 feed 가스조성 등을 모사하기 위해 합성가스 reforming 공정을 모델링하고 공급유량 및 압력 등의 운전변수는 GTL국책과제 1단계 연구수행 결과를 토대로 선정하고자 한다. GTL공정의 경우, 설비의 운전조건이나 연료가스의 구성 및 유량에 따라 적합한 reforming 공정이 다르기에 본 시뮬레이션 결과를 향후 GTL 플랜트 공정모델 설계시 reforming 공정선정에 참고자료로 활용하고자 한다.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.182-190
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• 2017

All liquids contain a small amount of gaseous components and the amount of gases dissolved in a liquid is in accordance with Henry's Law. In a multi-stage thermal-type seawater desalination plant, as the supplied seawater undergoes variations in temperature and pressure in each evaporator, the gases dissolved in the seawater are discharged from the liquid. The discharged gases are carbon dioxide, nitrogen, oxygen, and argon, and these emitted gases are non-condensable. From the viewpoint of convective heat transfer, the evaluation of non-condensable gas released during a vacuum evaporation process is a very important design factor because the non-condensable gases degrade the performance of the cooler. Furthermore, in a thermal-type seawater desalination plant, most evaporators operate under vacuum, which maintained through vacuum system such as a steam ejector or a vacuum pump. Therefore, for the proper design of a vacuum system, estimating the non-condensable gases released from seawater is highly crucial. In the study, non-condensable gases released in a thermal-type seawater desalination plant were calculated quantitatively. The calculation results showed that the NCG releasing rate decreased as the stage comes getting a downstream and it was proportional to the freshwater production rate.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1085-1093
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• 2017

Plasticizers are materials added to give softness and elasticity to plastics having rigid properties to give soft properties as products, and they are mainly added to high molecular materials to give flexibility to improve workability and to improve cold resistance, resistance to volatility and electrical properties. It is used for the purpose. Most plasticizers are inert liquids, similar in function to solvents but with high molecular weight and no volatility. In addition, when dissolved in petrochemical products, only the plasticizer is separated by the matrix effect with other compounds, and qualitative and quantitative analysis. In this study, qualitative and quantitative analysis of DOA and DOP, which are representative components of petrochemical products, were conducted using MD-GC/MS and developed an optimal plasticizer analysis method.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.119-126
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• 2012

Portland cement production-1.5billion tonnes yearly worldwide-contributes substantially to global atmospheric pollution(7% of total of $CO_2$ emissions). Attempts to increase the utilization of fly ash, by-products from thermal power plant to partially replace the cement in concrete are gathering momentum. But most of fly ash is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the sources of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effect reduction of $CO_2$ gas. In this study, we investigated the influence of the compressive strength of mortar on alkaline activator and curing condition in oder to develop cementless fly ash based alkali-activated concrete. In view of the results, we found out that it was possible for us to make alkali-activated mortar with 70MPa at the age of 28days by using alkaline activator manufactured as 1:1 the mass ratio of 9M NaOH and sodium silicate and applying the atmospheric curing after high temperature at $60^{\circ}C$ for 48hours.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.343-348
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• 2010

The surface of low density polyethylene (LDPE) film was oxyfluorinated under different reaction conditions to introduce hydroperoxide groups and change surface characteristics. Hydroperoxide functional groups created by oxyfluorination were used as active sites for graft polymerization with hydrophobic monomer, acryl amide (AM), and hydrophilic monomer, methyl methacrylate (MMA) to carry out the second modification of the LDPE film surface. The surface properties of the OFPE films and grafted OFPE films were characterized by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method, ATR-IR, contact angle measurement and DSC. From the results of DPPH method, the amount of hydroperoxide groups on the oxyfluorinated LDPE film continuously increased as the total pressure in the oxyfluorination and the partial pressure of fluorine gas increased. The water contact angle and surface free energy measurements showed that hydrophilic liquid (water) contact angle on LDPE film surface decreased with hydrophilic AM grafting and hydrophobic liquid (methylene diiodide) contact angle on LDPE film surface decreased with hydrophobic MMA grafting. These were attributed to AM or MMA monomer grafting and the wettability of LDPE filmsurface to hydrophilic and hydrophobic liquids were improved.

• KSBB Journal
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• v.30 no.1
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• pp.21-26
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• 2015

Plasma is an ionized gas mixture, consisting of neutral particles, positive ions, negative electrons, electronically excited atoms and molecules, radicals, UV photons, and various reactive species. Also, plasma has unique physical properties distinct from gases, liquids, and solids. Until now, non-thermal plasmas have been widely utilized in bio-medical applications (called bio-plasma) and have been developed for the plasma-related devices that are used in the medical field. Although numerous bio-plasma studies have been performed in biomedicine, there is no confirmation of the nonthermal effect induced by bio-plasma. Standardization of the biological application of plasma has not been evaluated at the molecular level in living cells. In this context, we investigated the biological effect of bio-plasma on living cells. Hence, we treated the fibroblasts with Dielectric Bauvier Discharge bio-plasma (DBD), and assessed the characteristic change at the molecular level, one of the typical cellular responses. Heat shock protein 70 (HSP70) regulates its own protein level in response to stimuli. HSP70 responds to heat shock by increasing its own expression at the molecular level in cells. Hence, we confirmed the level of HSP70 after treatment of mouse embryonic fibroblasts (MEFs) with DBD. Interestingly, DBD-plasma induced cell death, but there was no difference in the level of HSP70, which is induced by heat shock stimuli, in DBD-treated MEFs. Our data provide the basic information on the interaction between MEFs and DBD, and can help to design a molecular approach in this field.

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.81-84
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• 2006

Slot coating process, in continuous and patch modes, has been applied for the many precise coating products, e.g., flat panel displays and second batteries. However, manufacturing uniform coating products is not a trivial task at high-speed operations because various flow instabilities or defects such as leaking, bubbles, ribbing, and rivulets are frequently observed in this process. It is no wonder, therefore, that many efforts to understand the various aspects of dynamics and coating windows of this process have been made both in academia and industry. In this study, as the first topic, flow dynamics within the coating bead in slot coating process has been investigated using the one-dimensional viscocapillary model by lubrication approximation and two-dimensional model by Flow-3D software. Especially, operability windows in both 1D and 2D cases with various slot die lip designs have been successfully portrayed. Also, effects of process conditions like viscosity and coating gap size on slot coating window have been analyzed. Also, some experiments to find minimum coating thickness and coating windows have been conducted using slot die coater implemented with flow visualization device, corroborating the numerical results. As the second topic, flow dynamics of both Newtonian and Non-Newtonian fluids in patch or pattern slot coating process, which is employed in manufacturing IT products such as secondary batteries, has been investigated for the purpose of optimal process designs. As a matter of fact, the flow control in this system is more difficult than in continuous case because od its transient or time-dependent nature. The internal die and die lip designs for patterned uniform coating products have been obtained by controlling flow behaviors of coating liquids issuing from slot. Numerical simulations have been performed using Fluent and Flow-3D packages. Flow behavior and pressure distribution inside the slot die has been compared with various die internal shapes and geometries. In the coating bead region, efforts to reduce irregular coating defects in head and tail parts of one patterned coating unit have been tried by changing die lip shapes. It has been concluded that optimal die internal design gas been developed, guaranteeing uniform velocity distribution of both Newtonian and shear thinning fluids at the die exit. And also optimal die lip design has been established, providing the longer uniform coating layer thickness within one coating unit.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.226.1-226.1
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• 2010

본연구에서는 GTL(gas to liquids)공정의 합성가스 생산을 위해 수증기-이산화탄소 복합개질반응(Combined Steam and Carbon dioxide Reforming of Methane, CSCRM)을 수행하였다. CSCRM은 수증기와 이산화탄소의 공급비 조절을 통해 $H_2$/CO비를 2로 맞추기 용이한 장점을 지니고 있어 다른 단일 개질 반응과 달리 합성가스 생산 시 $H_2$/CO 비율을 조절하기 위한 부가적인 공정이 필요하지 않아 경제적인 공정이다. 일반적으로 사용되는 Ni개질촉매는 가격대비 우수한 성능을 보이지만 S/C비가 낮은 CSCRM의 경우 촉매표면의 탄소침적에 의한 비활성화가 야기되는 문제점이 있다. 따라서 본 연구에서는 산소저장능력과 산소전달능력이 우수한 $CeO_2$를 조촉매로 첨가하여 표면에 형성된 코크 제거가 용이하도록 하였다. Ni-Ce/$MgAl_2O_4$촉매는 동시함침법(co-impregnation)으로 제조하였으며, Ni의 함량을 10wt%로 고정한 상태에서 Ce의 함량을 조절하여 Ce/Ni 최적비를 찾고자 하였다. XRD, TPR, BET, $H_2$-Chemisorption과 같은 촉매의 특성분석을 통해 촉매의 비표면적, 환원특성과 Ni입자의 분산도 등을 확인하였다. Ce를 첨가함에 따라 Ce2.5wt%까지는 비표면적이 증가하다가 이후 점차 줄어드는 경향성을 보였다. 또한, $H_2$-Chemisorption 결과 역시 비표면적과 유사한 경향성을 보였는데, Ce5.0wt%까지 Ni 분산도가 증가 하다가 다시 감소하는 것을 확인할 수 있었다. 반응실험은 $H_2O:CO_2:CH_4:N_2$ = 0.8:0.4:1:1의 공급조건에서 수행하였으며, 질소와 수소 환원분위기로 $700^{\circ}C$에서 1시간 환원 후 $650^{\circ}C$에서 $550^{\circ}C$범위로 온도를 떨어뜨려가면서 반응을 수행하였다. Ce를 첨가함에 따라 $CH_4$ 전환율이 증가를 하다가 Ce2.5wt% 이후 감소하는 것을 확인할 수 있었다. 이러한 높은 촉매 활성은 Ce 첨가로 인해 환원특성이 좋아지고 Ni분산도가 증가하여 담체와 강한 상호작용(SMSI)을 형성함으로 탄소침적 저항성 강화에 기인한 것이다.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.701-711
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• 2020

Purpose: In this study, the risk of flammability of a liquid mixture was experimentally confirmed because the purpose of this study was to confirm the increase or decrease of the flammability risk in a mixture of two substances (combustible+combustible) and to present the risk of the mixture. Method: Flash point test method and result processing were tested based on KS M 2010-2008, a tag sealing test method used as a flash point test method for crude oil and petroleum products. The manufacturer of the equipment used in this experiment was Japan's TANAKA. The flash point was measured with a test equipment that satisfies the test standards of KS M 2010 with equipment produced by the company, and LP gas was used as the ignition source and water as the cooling water. In addition, when measuring the flash point, the temperature of the cooling water was tested using cooling water of about 2℃. Results: First of all, in the case of flammable + combustible mixtures, there was little change in flash point if the flash point difference between the two substances was not large, and if the flash point difference between the two substances was low, the flash point tended to increase as the number of substances with high flash point increased. However, in the case of toluene and methanol, the flash point of the mixture was lower than that of the material with a lower flash point. Also, in the case of a paint thinner, it was not easy to predict the flash point of the material because it was composed of a mixture, but as a result of experimental measurement, it was measured between -24℃ and 7℃. Conclusion: The results of this study are to determine the risk of mixtures through experimental studies on flammable mixtures for the purpose of securing the effectiveness of the details of the criteria for determining dangerous goods in the existing dangerous goods safety management method and securing the reliability and reproducibility of the determination of dangerous goods Criteria have been presented, and reference data on experimental criteria for flammable liquids that are regulated in firefighting sites can be provided. In addition, if this study accumulates know-how on differences in test methods, it is expected that it can be used as a basis for research on risk assessment of dangerous goods and as a basis for research on dangerous goods determination.