• Journal of Energy Engineering
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• v.25 no.1
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• pp.145-152
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• 2016

Recently, we can find news about toxic and combustible gas accident. So, we have to develop gas detector that can measure gas at dangerous area for preventing gas accidents. In this paper, we calculate a approximation function from sensor's output using the linear regressiong. And we develop software algorithm using Neville's algorithm for measuring gas concentration. Finally, we compare our algorithm with combustible gas detectors that are already developed, by using standard gas samples manufactured Korea Gas Safety. As a result of this experiment, we confirm that performance of our algorithm is more improved than performance of already developed combustible gas detectors. In the future, we'll research how to improve reliability from using count, temperature and humidity. And we'll design hardware applied explosion proof for safety.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.173.1-173.1
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• 2011

The high fuel flexibility of gas turbine power system has boosted their use in a wide variety of applications. Recently, the demand for biogas generated from the digestion of organic wastes and sewage waste water as a fuel for gas turbines has increased. We investigated the performance of high pressure biogas compression system and operating conditions for supplying biogas. The total flow per minute of biogas from food waste water digestion tank is $54Nm^3$. The main type of biogas compression system is the reciprocating system and screw type system. The target of biogas mechanical data is the as belows; inlet pressure 0.045bar, supplying biogas temperature is $30{\sim}60^{\circ}C$, and final pressure is above the 25 bar. Also, inlet conditions of biogas consist of CH4 48.5%~83%, $H_2S$ Max. 500ppm, $NH_3$ Max. 1,500ppm and Siloxane 2.7~4.6ppm. The boosting Blower system raises a pressure from 0.045bar to 1bar before main compressor. The main system lay out of reciprocating consisits of compressor driver, filter, cooling system, blowdown vessel, control system and ESD(Emergency Shut Down) system. And an enclosure package needs to be installed for reducing noise up to 75dB. The system driver is the electronic motor of explosion proof type. Forthe compressor system reliable operation, the cleaning system something like particulate filter needs to be set up in the inlet of compressor and Coalescing Filter in the outlet of compressor. Particulate Filter has to be removed above $10{\mu}m$ size of the particles in biogas. The coalescing filter(Micofine Borosilicate Glass Fibers Filter treated phenol acid) also removes moisture and oil of above $0.3{\mu}m$ to be involved in high pressure biogas up to 90%~98%.

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.248-256
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• 2020

In this study, predictive models based on machine learning for evaluating the extent of hazardous zone of explosive gases are developed. They are able to provide important guidelines for installing the explosion proof apparatus. 1,200 research data sets including 12 combustible gases and their extents of hazardous zone are generated to train predictive models. The extent of hazardous zone is set to an output variable and 12 variables affecting an output are set as input variables. Multiple linear regression, principal component regression, and artificial neural network are employed to train predictive models. Mean absolute percentage errors of multiple linear regression, principal component regression, and artificial neural network are 44.2%, 49.3%, and 5.7% and root mean square errors are 1.389m, 1.602m, and 0.203 m respectively. Therefore, it can be concluded that the artificial neural network shows the best performance. This model can be easily used to evaluate the extent of hazardous zone for explosive gases.

• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.55-61
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• 2004

This paper provided a counter measures against the troubles and accidents that are likely to take place in the power plant using hydrogen gas as a coolant for the cooling system of the generator. Because of the extremely wide flammability limits of hydrogen in comparison to the other flammable gases, the safety measures against the hydrogen accidents is very important to ensure the normal operation of electric-power facility. This study's purpose was a presentation of standard model of safety management of hydrogen equipments in the coal firing power plant such as following items: 1) providing the technical prevention manual of the hydrogen explosions and hydrogen fires occurring in the cooling system of power generator; 2) the selection of explosion-proof equipments in terms of the risk level of operating environment; 3) the establishment of regulations and counter measures, such as the incorporation of gas leakage alarm device, for preventing the accidents from arising, 4) the establishment of safety management system to ensure the normal operation of the power plant.

• Fire Science and Engineering
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• v.18 no.1
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• pp.18-23
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• 2004

This paper describes the minimum ignition limits for propane-air 5.25 Vol.% mixture gases in low voltage inductive circiuts. The improved effects on the ignition limit are studied by parallel safety components(resistors) for propane-air 5.25 Vol.% mixture gas in low voltage inductive circuits. The experimental devices used in this test are the IEC type spark ignition test apparatus. The minimum ignition limits are controlled by the values of current in inductive circuit. Energy supplied from electric source is first accumulated at the inductance, it's extra energy is working as ignition source of the explosive gas. The improved effects on the ignition limit are respectively obtained as the maximum rising rate of 330% by composing parallel circuits between inductance and resistor as compared with disconnecting inductance with the safety components. The more values of inductance increase the higher improved effects of ignition limit rise. The less values of resistor the higher improved effects of ignition limit rise. It is considered that the result can be used for not only data for researches and development of intrinsically safe explosion-proof machines which are applied equipment and detectors used in dangerous areas but also for datum for its equipment tests.

• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.167-174
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• 2019

Protective facilities are the last means of ensuring the survivability of personnel and assets, and there is a greater amount of matters to consider than those of general buildings. However, the Defense Military Facilities Criteria and the Ministry of the Interior and Safety, Ordinance No. 20, are only considering the expected enemy threats. In this study, we use objective and statistical methods to refine the consideration of the required capacity of protection based on the opinions of the experts. Specifically, the study adopts the Delphi technique associating the experts related to 30 defense military facilities criteria. The first-round questions were open-ended, and it compiled the points to consider related to the bulletproof and explosion - proof design. The second questionnaire was applied as closed questionnaire with 7 points scale methods. As a result of the factor analysis on the opinions of the experts, it was confirmed that the protection requirement level was due to METT + TC.

• Membrane Journal
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• v.21 no.1
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• pp.62-71
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• 2011

Highly enriched oxygen is used in energy-efficient combustion due to decreased non-flammable nitrogen, while high purity nitrogen is used for explosion proof in the LNG ships and keeping the freshness of green stuffs. Membrane technology can be used in these $O_2$ and $N_2$ generation with low energy consumption. In this study, PES was used as a membrane material and 1-methyl-2-pyrollidone (NMP) and acetone were employed as a good solvent and nonsolvent addictive (swelling agent to PES), respectively. Dope solutions were prepared by changing the content of acetone (0, 6.5, 15, 25, 31.5 wt%) in 37 wt% PES solutions. Hollow fiber spinning was performed at 0~10 cm of air-gap distances for each dope solution. $O_2/N_2$ selectivity and permeability were investigated by comparing of hollow fibers coated or not by silicons. $O_2/N_2$ selectivity increased and permeance of $O_2$ and $N_2$ decreased with increasing air-gap height independently of acetone addictions. Optimized PES hollow fibers were obtained with 37/6.5/56.5 wt% PES/acetone/NMP dope solution and 10 cm air-gap, which showed 7.3 of $O_2/N_2$ selectivity and 4.3 GPU of $O_2$ permeability after silicon coating.

• Journal of the Korean Institute of Gas
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• v.2 no.4
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• pp.79-84
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• 1998

This paper describes the minimum ignition limit voltages for LPG-Air 5.25[Vol$\%$] mixture gas by discharge sparks in radio-frequency limits using RF power supply and IEC type ignition spark apparatus. As a result, the minimum ignition limit voltages is increased in proportional to the rate of increasing of frequency in LPG-Air mixture gas. Especially, the minimum ignition limit voltages increase remarkably between 3[KHz] and 10[KHz]. It is considered that ignition is caused by one discharge until 3[KHz] and, beyond 3[KHz] ignitiof is caused by more than two discharges. The reason is analyzed that energy loss is caused by existing pause interval between discharges. It is considered that the result can be used for not only data for researches and development of intrinsically safe explosion-proof RF machines which are applied tole-equipments and detectors used in dangerous areas but also for datum for its equipment tests.