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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Institute of Gas
Journal Basic Information
Journal DOI :
The Korean Institute of GAS
Editor in Chief :
Volume & Issues
Volume 2, Issue 4 - Dec 1998
Volume 2, Issue 3 - Sep 1998
Volume 2, Issue 2 - Jun 1998
Volume 2, Issue 1 - Mar 1998
Selecting the target year
Characterization of A Catalystic Gas Sensor for Measuring Heat Content of Natural Gas
Lee K. Y. ; Maclay G. J. ; Stetter J. R. ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 1~6
A low power (below than 300 mW) catalytic bead combusible gas sensor is developed and utilized with a computer controlled sampling system for measuring heat content of natural gas. The heat content of gas is proportional to the change in the energy required to exposure to the sample of combustible gas. The heat content of natural gas samples ranging 36.30 - 39.88
is measured in the range of approximately
error, which is comparable to its nominal heat content. Each gas represents a slightly different curve of sensitivity to sensor temperature. Thus all of the sensitivities are not equal to every temperature. In calibration process the choice of a optimum operating temperature is an important factor that influences the overall performance of the measurement system.
Evaluation of Fracture Toughness in Steel Weldment for Inner Wall of LNG Storage Tank
Jang J.-i. ; Ju J.-B. ; Yang Y.-c. ; Kim W.-s. ; Hong S. H. ; Kwon D. ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 7~13
In this study, for the safety performance of LNG storage tank, the fracture toughness in X-grooved weld HAZ(heat-affected zone) of
Ni steel was evaluated qualitatively and quantitatively, and the relation with the change in microstructure was analyzed. The toughness assessment was peformed through the modified CTOD test proposed for thick weldment with X-groove. Additionally, microstructures of HAZ were evaluated by OM, SEM and XRD. From the results, HAZ toughness of SMA(shielded metal arc)-welded
Ni steel decreased as the evaluated region approached the fusion line. The decrease in toughness was apparently caused by the increase in the fraction of coarse-grained zone within HAZ. On the other hand, toughness drop with decreasing test temperature in F.L.(fusion line)
F.L.+3mm was larger than that in F.L.+5mm
F.L.+7mm region due to the fact that in the former regions, retained austenite had poor stability.
Radiation Damage by the Pool Fire of LNG Storage Tank
Sohn Jung-Hwan ; Hahn Yoon-Bong ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 14~22
In this work, in order to quantitatively predict the radiation flux and propose an idea about how to reduce the radiation damage, the radiation flux caused by pool fire of an LNG storage tank has been calculated using the RISC (Risk and Industrial Safety Consultant) proposed model under various conditions. Model predictions showed that the most important parameter affecting the radiation flux by the LNG pool fire is the wind speed. The extent of radiation damage to a target from fire flame was more significant with variation of wind speed at a low wind speed than with that at a high wind speed. It was found that the radiation damage by the former is substantially reduced with planting windbreak system around the plant. Since the windbreak is most economical than any other method, it is strongly suggested to plant a tree belt in the factory surroundings, especially near by the area of gas storage facilities, linking with water cooling and fire protection systems.
Study on the damage effect to the Gas pipeline coating by the crashed stone backfill material
Cho Sung Ho ; Jeon Kyung Soo ; Li Seon Yeob ; Cho Yong Bum ; Kho Young Tei ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 23~27
To protect the underground pipeline from the mechanical damage and to enhance the cathodic protection effect, the river sand has been backfilled traditionally around the buried pipeline. However, river sand became depleted and expensive. One has to seek for the economic alternative materials. Crashed stone is a good candidate for the backfill material. In this study, how much the particle size and shape of the crashed stone can effect on the gas pipeline coating was examined. A series of laboratory and field test was performed. In the Lab, the increasing loads were applied to the coated pipeline surrounded by the crashed stone, where no significant damage was observed.
A Study on the natural Convection and Radiation in a Rectangular Enclosure with Ceiling Vent
Park Chan-kuk ; Chu Byeong-gil ; Kim chol ; Jung Jai-hwan ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 28~39
This study investigated the natural convection and radiation in a rectangular enclosure with ceiling vent experimentally and numerically. A heat source is located on the center of the bottom surface. The analysis was peformed a pure convection and is combination of natural convection and radiation. The shape of the considered two dimensional model is a square whose center of ceiling(
) is opened. The numerical simulations are carried out for the pure natural convection case and the combined heat transfer case by using the SIMPLE algorithm. For the turbulent flow, Reynolds stresses are closed by the standard
model and the wall function is used to determine the wall boundary conditions. The experiment was performed on the same geometrical shape as the computations. The radiative heat transfer is analized by the S-N discrete ordinates method. The results of pure natural convection are compared with those of combined heat transfer by the velocity vectors, stream lines, isothermal lines. The results obtained are as follows 1. Comparing the results of pure convection with those of the combined convection-radiation through the shape of stream lines, isothermal lines are similar to each other. 2. The temperature fields obtained by numerical method are compared to those obtained by experimental one, and it is found that they are showed mean relative error
. 3. Visualization bt smoke is similar to computational results.
Mathematical Modeling on the Corrosion Behavior of the Steel Casing and Pipe in Cathodic Protection System
Kim Y.S. ; Li S.Y. ; Park K.W. ; Jeon K.S. ; Kho Y.T. ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 40~46
Mathematical modeling on the corrosion of the steel casing and main pipe due to the protection current resulting from a cathodic protection system was carried out using boundary element method. The model is consisted of Laplace's equation with non-linear boundary conditions(Tafel equations) and the iterative technique to determine the miexed potential of the steel casing. The model is applied to the normal steel casing section as well as abnormal one with defects such as metal touch and insulation defects. From the modeling procedure, we can calculate the potential distributions and current density distributions of the system. The theoretical results of the qualitatiive corrosion aspect along the steel casing and main pipe agree well with the experimental results within the experimental conditions studied.
Study on improvement of efficiency of gas filter at the natural gas valve station
Cho Y.B. ; Jeon K.S. ; Her J.Y. ; You K.H. ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 47~52
To eliminate foreign substance like metal rust and sand in natural gas pipeline, 250um strainer filter is used present in Korea Gas Corporation. But particles smaller than 250um passing the filter have bad effects to the valves and the measuring equipments. In order to eliminate small paticle in the pipeline, it is necessary to cut down the pore size of filter When we cut down the pore size of filter, the pressure difference between the front of filter and that of the rear part is increasing and disturb normal condition of gas supply. So it is very important to control the condition between the pore size of filter and the pressure difference. In this study, using head loss coefficient K, the estimation method of efficiency of gas filter according to the pore size and the pressure difference is presented.
A Study on the Automatic Synthesis of Signed Directed Graph Using Knowledge-based Approach and Loop Verification
Lee Sung-gun ; An Dae-Myung ; Hwang Kyu Suk ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 53~58
By knowledge-based approach, the SDG(Signed Directed Graph) is automatically synthesized, which is commonly used to represent the causal effects between process variables. Automatic synthesis of SDG is progressed by two steps : (1)inference step uses knowledge base and (2)verification step uses Loop-Verifier. First, Topology and Knowledge Base are constructed by using the information on equipment. And then, Primary-SDG is synthesized by Character Pattern Matching between Variable-Relation-Representation generated by using Topology and Variable-Tendency-Data contained in Knowledge Base. Finally, a modified SDG is made after the Primary-SDG is verified by Loop-Verifier.
Studies on the Morphology and Thermal Properties of the Polyurethane Synthesized from 4,4'-Diphenylmethane Diisocyanate (MDI) and Polyester Polyol
Jung Hyun Chul ; Kang Sung Joong ; Kim Woo Nyon ; Kim Sang Bum ; Lee Yeong Beom ; Hong Seong Ho ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 59~65
Morphology and thermal properties of polyurethane synthesized from 4,4'-diphenylmethane diisocyanate (MDI), polyester polyol, and 1,4-butane diol are investigated using fourier transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC), and dynamic mechanical thermal analysis (DMTA). From the FT-IR study, it is found that the stretching peaks of hydrogen bonded N-H and C=O are shifted to the low frequencies with the increase of hard segment content of the polyurethanes. The shift of the stretching peaks of hydrogen bonded N-H and C=O indicates that the degree of hydrogen bonding is increased. From the DSC study, it appears that the glass transition temperature (
) of the polyurethanes is increased with the increase of the hard segment content. Also, it is found that the polyurethanes investigated in this study have the homogeneous network structure due to the high functionality of the MDI. From the DMTA study, transition of the soft segment was not found. Therefore it is concluded that the polyurethanes investigated in this study have the one-phase morphology which is consistent with the DSC results.
Analysis of the Characteristics of Flue Gas in Infrared Mobile Heaters for Gas Room Heating
Kim Young-Gyu ; Kwon Jeong-Rock ; Kim Chung-Kyun ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 66~73
This paper deals with the combustion characteristics of flue gas in infared mobile heaters. The experimental work has been performed to obtain the concentration levels and combustion characteristics of flue gas with varying chamber size and room temperature. The experimental results showed that oxygen depletion sensor device was operated at the oxygen concentration level of
for all the chamber size. The combustion characteristics of oxygen and carbon dioxide show a linearity After 10 minutes the combustion property of carbon monoxide occurs at random without a level of oxygen and carbon dioxide in closed space of the heater. In these results, it is very important to prevent incomplete combustion through a sufficient ventilation, and accident prevention with a reduction of the oxygen and diffusion of toxic carbon monoxide.
Assessment of Material Degradation of High-Temperature Components for Process Plant by Grain Boundary Etching Method
Han Sang In ; Yoon Kee Bong ; Kim Ji Yoon ; Chung Se Hi ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 74~82
The grain boundary etching method as a technique for assessing degradation of structural materials used at elevated temperature has received much attention since it is simple, inexpensive and easy to apply to real plant components. In this study, the technique is applied to some aged petroleum and chemical plant components such as reactors and drums. As a degradation parameter, intersection number ratio (
), is employed. The intersection number ratio (
) is defined as the ratio of intersection number (
) obtained from 5-minute picric acid etched surface to the number (
) obtained from Nital etched surface. In order to study degradation level, several relationships were measured such as the correlation between shift in ductile brittle transition temperature,
and intersection number ratio, (
) and the correlation between the measured (
) values and Larson-Miller Parameter values.
A Study on Effects of Temperature Difference between the Inside and Outside the Meter-Run on Natural Gas Flow Measurement Errors
Ha Youngcheol ; Lee Chulgu ; Chang Seungyong ; Lee Kangjin ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 83~89
Experiments had been conducted Qualitatively regarding flow measurement errors of orifice flowmeter due to temperature difference between the inside and outside the natural gas meter-run in case of no pipe insulations. The primary factors considered in this study are fluid velocity and surrounding temperature. In addition, a portion of thermal radiation due to the sun was involved as a factor. The results showed that the considerable errors were not detected even in conditions of low flow rates and large temperature difference between the inside and outside the meter-run.
A Study on Development of Fire Accident Analysis System Using Classification Model and Database
Kim In-Tae ; Heo Jaeseok ; Song Hee-Oeul ; Ko Jae-Wook ; Kim In-Won ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 90~98
In order to establish detailed plans for fire protection and reduce the possible fire accidents in the future, collection of domestic and foreign fire accident cases and fundamental analysis are very important. In this study the classification model for fire accidents was developed and the direction to a new model was suggested by comparison ours with the accidents classification model of NFPA of United States of America and Japan. A new developed PC-based database program for fire accidents (FADBS) was used to analyse fire accidents easily and efficiently.
Impact Properties and Fractography of Structural Materials for LNG Tank at Cryogenic Temperatures
Shin Hyung-Seop ; Lee Hae-Moo ; Shin Ju-Yeong ; Park Jong-Seo ;
Journal of the Korean Institute of Gas, volume 2, issue 1, 1998, Pages 99~106
In order to investigate the impact properties of structural materials for LNG tank, instrumented Charpy impact tests were carried out at cryogenic temperatures.
Ni steel showed a superior fracture resistance because of less degradation in toughness until 77 K. From the load-deflection curve obtained by an instrumented methods it was found that with the decrease of temperature from 173 K to 77 K, the peak load in the curve increased, but the total absorbed energy decreased. In addition, the energy absorbed during the crack growth was larger than one absorbed in the process of crack initiation. In SUS304L material, the energy absorbed in the process of the crack initiation was relatively large, but the energy absorbed in the process of crack growth was small, the behavior of absorbed energy was well agreed with the observations of the fracture surface which showed a relatively smooth fracture surface. The absorbed Charpy impact energy in the case of A5083 alloy was lower as compared with other steels, and some cracks were observed along the crack propagation direction at the fracture surface of 77 K.