• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.1-5
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• 2006

With the rapid increase in gas consumption, the role of pipelines as a transportation means of natural gas is increasing. In general, when natural gas is being transported in pipelines, some liquid mainly from formation of condensate is introduced and this phenomenon makes operational problems more complex in the gas industry. Thus, an appropriate method is necessary for predicting the effect of presence of gas condensate on operational efficiency. In this study, a statistical model was developed using an integrated single- and two-phase flows concept. Using this model, the effects of the incipient point of gas condensate and its quantity on outlet pressure were analyzed. Also, the effect of variations of flow regimes in two-phase region on outlet pressure after the incipient point was analyzed.

• Journal of Korean Society of Transportation
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• v.32 no.1
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• pp.1-12
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• 2014

The tier 3 methodology used in estimation of greenhouse gas emissions from road sectors is based on mileage data. However, such data can neither accurately represent the mileage of regional unit nor have sufficient integrated data reflecting the characteristics by region, vehicle type, fuel type and road type. Such estimation of greenhouse gas emissions is not reliable. Accordingly, the purpose of this study is, firstly to accumulate activity data based on distance traveled which enables us to accurately estimate the amount of green gas emitted by regional unit(emission point), and secondly, to develop a methodology for estimation of greenhouse gas emissions using these data. To do this, the study utilizes the mileage data of Korea Transportation Safety Authority(TS), statistics of registered motor vehicles, statistical yearbook of traffic volume from the Ministry of Land, Infrastructure and Transport(MLIT), the Korea Transport Database of the Korea Transport Institute(KOTI), and average road speed by local government. Methodology for estimation by local government level(emission point) is meaningful, because it reflects traffic pattern data including flow in and out and internal traffics. Finally, to verify the methodology presented in this study, it is applied to Seoul. Both greenhouse gas estimates, one by multiplying the average mileage and the number of registered vehicles and the other by multiplying traffic volume and road extension, are less than the amount estimated by the methodology presented in this study.

• Corrosion Science and Technology
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• v.7 no.5
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• pp.288-295
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• 2008

The increase use of natural gas as an energy source has been continuous demand for ever-increasing strength in gas transmission pipeline materials in order to achieve safe and economic transportation of natural gas. In particular, linepipe material for sour gas service primarily needs to have crack resistant property. However, applications of sour linepipes are expanding toward deep water or cold region, which require higher toughness and/or heavier wall thickness as well as higher strength. To improve the crack resistance of linepipe steel in sour environment, low alloy steel are produced by controlled rolling subsequently followed by the accelerated cooling process. This paper summarizes the design concepts for controlling crack resistant property low alloy linepipe steels for sour gas service.

• Journal of Institute of Convergence Technology
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• v.6 no.1
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• pp.31-35
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• 2016

In this paper, the present status of shale gas development was briefly introduced and intended the growing importance and shale gas as a source of chemicals. The large amounts of shale are expected to be produced thereby, a wealth of methane and ethane will be provided as a raw material of ethylene. This manuscript also focus on the influence of potential volumes of shale gas on petrochemical industry, especially domestic one based on naphtha cracking because ethane cracking can offer cost effective ways to convert methane to higher value chemicals.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.51-61
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• 2022

Gas separation via hollow fibre membrane modules (HFMM) is deemed to be a promising technology for natural gas sweetening, particularly for lowering the level of carbon dioxide (CO₂) in natural gas, which can cause various problems during transportation and process operation. Separation performance via HFMM is affected by membrane properties, module specifications and operating conditions. In this study, a mathematical model for HFMM is developed, which can be used to assess the effects of the aforementioned variables on separation performance. Appropriate boundary conditions are imposed to resolve steady-state values of permeate variables and incorporated in the model equations via an iterative numerical procedure. The developed model is proven to be reliable via model validation against experimental data in the literature. Also, the model is capable of capturing axial variations of process variables as well as predicting key performance indicators. It can be extended to simulate a large-scale plant and identify an optimal process design and operating conditions for improved separation efficiency and reduced cost.

• Journal of Institute of Convergence Technology
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• v.12 no.1
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• pp.19-23
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• 2022

Interest in hydrogen production to respond to climate change is increasing. Until now, hydrogen has been mainly produced through the SMR (Steam Methane Reforming) process using natural gas. A large amount of CO₂ is emitted in the hydrogen production process through SMR, and the gas flow including CO₂ generated in the SMR process has different characteristics for each emission source, so it is important to apply a suitable CO₂ capture process. In the case of PSA tail gas or synthesis gas, the applicability of an amine-based process has been confirmed or demonstrated close to a commercial level. However, in the case of the flue gas generated from the reformer, it is still difficult to apply the conventional amine-based process because the partial pressure of CO₂ is relatively low. Energy-saving innovative absorbents such as phase separation absorbents can be a solution to these difficulties.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.179-185
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• 2017

This article describes the characteristics of nondispersive infrared carbon dioxide gas sensor according to the temperatures and humidifies. In this researches, a thermopile sensor that included application-specific integrated circuit (ASIC) was used and the White-cell structure was implemented as an optical waveguide. The developed sensor modules were installed in gas chamber and then the temperature of gas chamber has been increased from 283 K to 313 K with 10K temperature step. In order to analyze the effects of humidity levels, the relative humidity levels were changed from 30 to 80%R.H. with small humidifier. Then, the characteristics of sensor modules were acquired with the increment of carbon dioxide concentrations from 0 to 2,000 ppm. When the initial voltages of sensors were compared before and after humidifying the chamber at constant temperature, the decrements of the output voltages of sensors are like these: 9mV (reference infrared sensor), 41 mV (carbon dioxide sensor), 2 mV (temperature sensor). With the increment of ambient temperature, the averaged output voltage of carbon dioxide sensor was increased 19 mV, however, when the humidity level was increased, it was decreased 14mV. Based upon the experimental results, the humidity effect could be alleviated by the increment of temperature, so the effects of humidity and temperature could be only compensated by the ambient temperature itself. The estimated carbon dioxide concentrations showed 10% large errors below 200 ppm, however, the errors of the estimations of carbon dioxide concentrations were less than ${\pm}5%$ from 400 to 2,000 ppm.

• Journal of Energy Engineering
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• v.10 no.3
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• pp.233-242
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• 2001

This paper attempts to analyze the effects of promotion of natural gas vehicles (NGVs) on LNG storage facilities and load patterns, and to verify economic feasibilities of NGVs as a DSM (Demand-Side Management) strategy. For these purpose, we have established an econometric mode. Results from the model indicate that natural gas demand in transportation sector will increase continuously, having a 7.84% share in total natural gas demand in 2014. By this analysis, the increased use of NGVs can result in a decreased requirement on the volume of around 1.3 LNG tanks lower in 2014. Also, it shows that TDRs can be reduced by 0.4 for the city gas and by 0.15 for the total LNG in 2014. As a conclusion, we suggest that the promotion of NGVs may play an efficient role as a DSM strategy, and should be considered as a promising strategy to optimize the investment needs in LNG sector as well as an environmental protection measures. Lastly, we acknowledge that a transportation module in our model is based on a Korean government's NGVs promotion plan, not on a market function.

• Journal of the Korean Institute of Gas
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• v.26 no.5
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• pp.22-27
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• 2022

Atomic Layer Deposition (ALD) is a facility that deposits an atomic layer on a wafer by causing a chemical reaction after decomposition using heat or plasma by inputting two or more gases during the semiconductor process. The main gas used at this time is NH₃ (Ammonia). NH₃ has a relatively narrow explosive range with an upper limit (UFL) of 33.6% and a lower limit (LEL) of 15%, but it can explode if a large amount suddenly gathers in one place. It is Velocity and fatal if inhaled or in contact with the skin. NH₃ (Ammonia) of ALD (Atomic Layer Deposition) facility is supplied to the chamber through the gas inlet and discharged after the reaction.

• Journal of the Korean Society for Railway
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• v.17 no.3
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• pp.216-222
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• 2014

In general, the rail transportation recognized as a better transportation mode than road transportation in terms of the environment. However, due to a lack of quantitative analysis based on Korean data, foreign cases for environmental advantages of the railway have often been cited in Korea. To address this issue, we estimated the energy consumption of passenger and freight transportation using certified activity data from Korea Railroad Statistics and the Electrical Work Report for railway and the Energy Consumption Survey for road. We estimated the Green House Gas emission of passenger and freight transportation on a Tier 1 level by applying the IPCC 2006 Guideline. Finally, we calculated the energy consumption unit and GHG emission unit to determine the environmental impact of rail and road transportation. We also compared the analyzed results of high-speed rail and auto as typical means of rail and road transportation.