• Journal of the Korean Institute of Gas
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• v.4 no.1 s.9
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• pp.63-68
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• 2000

We have developed a new relief valve which is a safety device for the domestic gas-fired hot water boilers. The relief valve has been designed to expand the inner diameter of the inlet, the outlet and the seat of the valve considering the relief capacity, and also to separate the spring from the room heating water. Therefore, we could minimize the adhesion and/or obstruction of the inlet and the corrosion phenomena of the spring which used to be the problem of the conventional relief valves. Test results of the developed relief valve showed that the performance of the opening pressure, reseating pressure, tightness, endurance were excellent, and the operating boiler with developed relief valve was evaluated as very good. The standardization and application of the relief valve can provide the advantage of component exchange and easy maintenance and repair.

• Korean Journal of Hazardous Materials
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• v.6 no.2
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• pp.77-86
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• 2018

Interest in renewable energy is increasing for eco-friendly use of energy, and fuel cells are being used in various ways such as houses and buildings as power generation methods that have low emissions such as $NO_X$ and $CO_2$. As the supply of fuel cells expands, more and more boilers are installed in the existing buildings, but safety management is not being performed properly. Therefore, in this study, a prior study was conducted on the status of fuel cell-boiler complex installation and related criteria, and the risk factors were analyzed according to the installation environment and structure. Based on these standards, the safety performance of the fuel cell-boiler combined installation is assessed by conducting a demonstration using the starting product of the simulated operation to derive the installation criteria (proposal) for the fuel cell-boiler combined installation. The installation criteria (proposal) include the construction and connection method of the piping according to the fuel cell-boiler complex installation.

• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.139-146
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• 2014

As Crosby notes, the most companies spend 15 to 20% of their sales dollars on quality costs. Generally the most effective way to manage quality costs is to avoid having defects in the first place. In this paper we have studied about the repair(service) problem of domestic gas boiler within warranty period. We develop a system, which man could find the cause of the problem at an early stage and could devise a countermove to the problem under supposing that the service(repair) rate follows exponential distribution and the product is manufactured lot-for-lot continually. Using the developed early sensing system. it is expected to improve the reliability of the product, to save expenses of company and to improve customer's satisfaction. And the system will be expended to incorporate information technology, which can detect the repair rate automatically.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.60-67
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• 1995

Ocassionally, many chemical plants experienced unexpected shutdown and suffered serious economic loss caused by boiler accidents due to mis-operations during the start-up or shutdown. A strategy to prevent such accidents is proposed here by using the form of frame for the recognition of all needed conditions, i.e., the states of the boiler, hazardous or dangerous conditions, each level conditions, transition network and heuristic knowledge of human operators. The expert system based on this strategy is considered to be an available method to predict all of the hazardous conditions in boiler plants.

• Journal of the Korean Society of Safety
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• v.12 no.1
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• pp.60-70
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• 1997

Since, human error is a major factor contributing to disaster during start-up of operation in Boiler plant. it is necessary to develop an automation system which prevent mode of operation that are known to be dangerous and to bring a loss of energy. The aim of this study is to suggest a model for the computer-aided synthesis of operation sequence as a part of automation system for start-up operation. Synthesis is accomplished by the formation of a hierarchical network of goals which decide sequence of operations. Hierarchical Network is formed by using method which upper goals ( i.e. upper operation al situation) are classified by the function of themselves into lower goals (i.e. lower operational situation). Knowledge for deciding operation sequence is generated by putting In order the knowledge of hazard operation and energy management.

• Journal of the Korean Society of Safety
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• v.24 no.3
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• pp.1-6
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• 2009

Recently power plants and oil refineries are focusing on capacity enlargement for better efficiency through higher temperature and higher pressure. Thickness of boiler tubes becomes lessened due to oxidation and erasion caused by high temperature bums gas flowing over tubes outside. Accordingly, mechanical stress of tubes is increasing and that is a critical factor to make a crack and fracture. To prevent those sorts of accidents, aging assessment for proper periodic repair and replacement should be conducted reliably and reasonably. We performed IIT test on Cr-Mo steel, one of the most heat-resistant materials for facilities in power plants, and we report the test result and the considerable effectiveness of IIT test.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.22-28
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• 2001

Heat transfer and pressure distribution for heat exchanger type of domestic gas boiler are different from shape, pitch, thickness of fin and array of pipe respectively. In order to measure the pressure distribution across the heat exchanger, a suction type wind tunnel was constructed and velocity distribution was measured for pilot tube(4 point) of rack type. The experiments were performed for 5 different air flow mass, rpm=3,6,9,12,15 and transverse axis of heat exchanger(x-length) is 5cm respectively. Results showed that above 9.5m/s, pressure distribution dispersion for wet type of heat exchanger is on the increase and above 5.5m/s, pressure distribution dispersion for dry type of heat exchanger is on the increase. Also, pressure distribution dispersion by comparing two different types heat exchanger, dry type of heat exchanger showed a higher augmentation than wet type of heat exchanger.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.143-153
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• 1996

Shutdown of boiler plants is a dynamic, complicated, and hazardous operation. Operational error is a major contributor to danserous situations during boiler plant shutdowns. It is important to develop an automatic system which synthesizes operating procedures to safely go from normal operation to complete shutdown. Knowledge representation for automatic shutdown of boiler plants makes use of the hierarchical, rule-based framework for heuristic knowledge, the semantic network, frame for process topology, and AI techniques such as rule matching, forward chaining, backward chaining, and searching. This knowledge representation and modeling account for the operational states, primitive operation devices, effects of their application, and planning methodology. Also, this is designed to automatically formulate subgoals, search for positive operation devices, formulate constraints, and synthesize shutdown procedures in boiler plants.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.131-140
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• 2003

An accident involving a boiler can result in a disaster since it handles high-pressurized steam so that it may cause an explosion. Therefore, the boiler is very susceptible to industrial accidents. This thesis aimed to develop counter-plans to prevent industrial accidents involved the boiler. At first after collecting accident cases involving boilers, a survey on the trait of them was carried out. Ant on the other hand a qualitative analysis was conducted to draw out hazardous components in the boiler itself and their inherent relative importance was assessed. Through this procedure, 'negligence of unsafe condition' was noted as the major cause for unsafe acts whereas 'fault in work procedure' for unsafe condition. In the meanwhile, results of a hazard analysis using FMEA technique ranked gas safety devices, a switch preventing gas from under-pressurization, protect relays high. In particular, it was pointed out that the water feeding and steam subsystem has more components in hazard than other subsystems. Considering these analyses results, counter-plans to improve safety management was suggested also.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.518-524
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• 2013

In this study, we conducted a study on characteristics of exhaust gas emissions from boiler when water-bunker oil mixed by homogenizer was burned in boiler. The results showed that NOx concentration and CO concentration of the homogenized bunker oil was decreased by 19% and 54% compared to pure bunker oil pretreatment was not being performed. And, in the case of water-bunker A oil, the NOx concentration was decreased with increasing water mixing ratio in bunker A oil. In particular, the NOx concentration in exhaust gas of 20 %water-80 %bunker A oil decrease by 45 % compared with pure bunker-A. However, the CO concentration in exhaust gas of 20 %water-80 %bunker A oil shows irregular changes. This means that the mixing of water more than a certain amount can cause a decrease in combustion performance. From this result, it can be found that critical mixing ratio of water in bunker A oil for normal combustion is 15% in this study. Deposition amount of soot that is collected in the vicinity of the chimney was decreased with increasing water mixing ratio.