• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.35-40
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• 2011

An experimental study of the flame response in a turbulent premixed combustor has been conducted in order to investigate mechanisms for combustion instabilities in a lean premixed gas turbine combustor. A lab-scale combustor and mixing section system were fabricated to measure the flame transfer function. Measurements are made of the velocity fluctuation in the nozzle using hot wire anemometry and of the heat release fluctuation in the combustor using chemiluminescence emission. The results show that the flame transfer functions are greatly dependent on the modulation frequency as well as operating conditions such as equivalence ratio. Flame dynamics can be generalized as a function of Strouhal number which is a ratio of flame length to modulation wave length.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.1
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• pp.60-68
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• 2000

Biofiltration is an environmentally-sound technology for elimination of VOCs and odorous compound from low-concentration, high-volume waste gas streams because of its simplicity and cost-effectiveness. It can be appled to the treatment of gases from publicly owned treatment works, composting facilities, landfill sites, and soil vapor extraction systems. The ability to design an effective biofilter system involves a combination of fundamental biofilter knowledge, practical experience, and bench- and pilot-scale testing. The objective of this paper was to review principle, design parameters, operational conditions, case studies, and economy of biofiltration through literature.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.2
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• pp.19-38
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• 2023

Nitrous oxide, one of the six greenhouse gases from Kyoto protocol, is known to be emitted in biological nitrification and denitrification reactions at wastewater treatment plant. In this study, EQPS which is a computer program that can simulate nitrous oxide gas emission amount at wastewater treatment plants is used. The MLE process which treats wastewater from combined sewer is studied. Operational variables which are MLR, water temperature at reactor and primary clarifier by-pass percentage are changed to define the condition which produces the least amount of nitrous oxide gas. 200 % of MLR, 20 ℃ of water temperature at bioreactor and 15 % of primary clarifier by-pass percentage are shown the least nitrous oxide emission factor. Also, it is found that the deep aeration tank produces less amount of nitrous oxide gas since less air is required to meet oxygen demand in this type of aeration tank.

• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.41-47
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• 2012

There are PFD(Process Flow Diagram) and P&ID(Piping and Instrument Diagram) for designing and managing chemical process efficiently. They provide the operation condition and equipment specifications of chemical process, but they do not provide the reliability of chemical process. Therefore, in this study, Reliability Flow Diagram(RFD) which provide the cycle and time of preventive maintenance has been developed using Directed Graph Analysis methodology. Directed Graph Analysis methodology is capable of assessing the reliability of chemical process. It models chemical process into Directed Graph with nodes and arcs and assesses the reliability of normal operation of chemical process by assessing Directed Graph sequential. In this paper, the chemical process reliability transition according to operation time was assessed. And then, Reliability Flow Diagram has been developed by inserting the result into P&ID. Like PFD and P&ID, Reliability Flow Diagram provide valuable and useful information for the design and management of chemical process.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.49-57
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• 2016

In this study, a thermal hydrolysis technology was used to treat the poultry carcasses that were killed due to Avian Influenza (AI) occurrence, as well as to determine the possibility of fueling for the resultant products. Experimental results showed that the poultry carcasses were liquefied except for sand, and showed the optimum efficiency at $190^{\circ}C$ and operating time of 60 minutes. It has been shown that liquid products obtained after thermal hydrolysis has good conditions for fuel conversion since it had high carbon contents and calorific value, as well as low ash content. In addition, it was possible to operate the thermal hydrolysis facility by using only the waste heat generated in the combustion without injecting the auxiliary fuel, and the exhaust gas generated in the combustion has a small influence on the atmosphere.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.693-699
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• 2011

Internal combustion engines running on syngas, which can be obtained from biomass or organic wastes, are expected to be one of the suitable alternatives for power generation, because they are environment-friendly and do not contribute to the depletion of fossil fuels. However, syngas has variable compositions and a lower heating value than pure natural gas, owing to which the combustion conditions need to be adjusted in order to achieve stable combustion. In this study, a gas that has the same characteristics as syngas, such as low heating value (LHV), was produced by mixing $N_2$ with compressed natural gas (CNG). In addition, this study investigates the combustion characteristics of syngas when it is mixed with hydrogen in a ratio ranging from 10% to 30% with a constant LHV of total gas.

• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.40-44
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• 2009

This is a comparative structural analysis for a steel roof LNG storage tank that has some advantages relatively in designing larger scale tanks and construction cost, etc. compared with a conventional concrete roof LNG storage tank as the capacity of LNG storage tanks is bigger. Structural analysis was performed on a 200,000$k{\ell}$ steel roof LNG storage tank and a concrete of the same capacity in condition of three critical load combination cases, a normal operation, a LNG spillage and seismic case by using finite element method. And comparative structural safety evaluation was carried out by using strength ratio in places of concrete wall, foundation and roof with a quantitative method.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.65-75
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• 2022

Recently, the possibility of fire and explosion due to hydrogen leakage and the resulting risk are increasing since the operating pressure of the electrolysis increases. This study performed the hazardous area classification in accordance with KS C IEC 60079-10-1 and KGS GC101 in consideration of the general operating conditions of the electrolysis. In addition, in order to achieve a To Non-hazardous, an appropriate ventilation rate was estimated to maintain a concentration of less than 25 % of the lower explosive limit. As a result, it was reviewed that the electrolysis is classified as an hazardous area when only natural ventilation is applied, and a huge amount of ventilation is required to classify it as a non-hazardous area.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.107-111
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• 2017

The reliability on high cycle fatigue damage mechanism for new blades manufactured by reverse-engineering is demonstrated by success-run test. Turbine blades always experience various dynamic loads in turbine operation, as well as being in resonance condition and forced by fluid-induced vibrations mostly during run-up/down, which may accumulate high cycle damage to the blades. The accidents caused by blade failure especially incur not only a lot of troubles to the machinery but also huge financial losses. Therefore it is necessary to verify the reliability of blades in advance for the safe use. The success run test for the reliability demonstration is designed and performed for the new blades using the technique known as resonant high cycle fatigue testing.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.2
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• pp.93-101
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• 2019

The mechanical properties and microstructure of 1st stage used and casted buckets of $1,100^{\circ}C$ class gas turbine were analyzed to evaluate quality of the components. Gas turbine 1st stage buckets are exposed and operated in the most severe environment except 1st nozzle among the hot path gas components. Additionally, since the 1st stage bucket is a rotating component, so it may cause additional damage to the rear buckets and nozzles which cause a huge financial loss. Therefore, the quality of the casted bucket must be evaluated prior to use at the plant site. In this study, the microstructure analysis and mechanical properties of the casted bucket were evaluated to verify the casting quality and it was confirmed that the quality conditions designed by KEPCO were satisfied. A bucket operated 46% (11,067EOH) of its life time also evaluated for quality comparison.