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Nowadays, a number of sensors which are placed in industrial complex are monitoring areas involving chemical leak and other faults. However, even in the presence of the sensors, chemical leaks, sometimes involving huge amount of chemicals, continuously led to big losses in the industrial complex. In most industries, sensor installation has been performed using past experience or using senor manufacturers` guideline; which leads to poor performance of the installed sensor grid. Therefore, we investigate an optimal placement methodology of point sensors for rapid detention and response when chemical leaks happen. This research suggests a generalized formulation suitable for the optimized decision making of minimizing number of sensors to be placed and increasing the fraction of covered scenarios under assumption of negligible effect of other structures. The proposed method has been verified for suitable performance for simple leak scenario simulations, by achieving the safety objectives and guaranteeing safe process operations.

Looking at the large and small fire, explosion, or release accidents that occurred recently, we can see that the accident of subcontractor workers has been increased in the contractor workplace while a harmful or dangerous maintenance works. In this study, the actual status of subcontractor's safety management was examined by using the questionnaire to the contractor who submitted the process safety report. In order to improve the safety management of subcontractors, the responsibility and rational role-sharing between the contractors and subcontractors were reviewed. Also, Providing safety and health information and worker protection measures during maintenance were investigated. The results of this study can be used to help strengthen and improvement safety management of the subcontractor at the time of a hazardous or dangerous works. In addition, it will be utilized to reduce industrial accidents and to build mutual cooperation relationship between contractor and subcontractor.

Carbon dioxide was designated as one of greenhouse gases that cause global warming. Among various ways to solve the emission issue, the 3rd-generation biomass (algae) production is considered as a viable method to reduce in the atmosphere. In this research, we propose a design of an innovative sustainable production system by utilizing the 3rd generation biomass in the environment of floating production storage and offloading (FPSO). Existing biomass production systems depend on the solar energy and they cannot continue producing biomass at night. Electricity produced from offshore wind farms also need an efficient way to store the energy through energy storage system (ESS) or deliver it real-time through power grid, both requiring heavy investment of capital. Thus, we design an offshore grid structure harnessing LED lights to supply the necessary light energy, by using the electricity produced from the wind farm, resulting in the maximized production of biomass and efficient use of wind farm energy. The final design integrates the biomass production system enhanced by LED lights with a wind power generation. The suggested NLP model for the optimal design, implemented in GAMS, would be useful for designing improved offshore biomass production systems combined with the wind farm.

A suitable monitoring method is necessary for successful policy implementation and its evalua-tion, required for effective prevention of abnormal fire occurrences. To do this, there were studies for applying control charts of quality management to fire occurrence monitoring. As a result, it was proved that more fire occurs in winter and its trend moves yearly-basis with some patterns. Although it has trend, if we apply the same criteria for each time, inefficient overreacting fire prevention policy will be accomplished in winter, and deficient policy will be accomplished in summer. Thus, applying different control limits adaptively for each time would enable better forecasting and monitoring of fire occurrences. In this study, we treat fire occurrences as time series model and propose a method for configuring its coefficients with ARIMA model. Based on this, we expect to carry out advanced analysis of fire occurrences and reasonable implementation of prevention activities. Key words : fire occurrence pattern, time series, ARIMA model, autocorrelationKIGAS Vol. 19, No. 2, pp 20~28, 2015 http://dx.doi.org/10.7842/kigas. 2015.19.2.20(Journal of the Korean Institute of Gas)

To assess downward positions of water spray for the small-scale release of chlorine gas, dispersion coefficients for the Gaussian dispersion model were validated at the small-scale release experiment. And the downwind distances of water spray were assessed with the simulated results. As results, the Gaussian plume model using the Briggs’ dispersion coefficient well estimated the dispersed characteristics for small-scale release of chlorine gas. The best adequate downwind position of water spray is the position of the maximum concentration of chlorine at the ground level. And the adequate vertical and horizontal dimensions of water spray consider the maximum width and height of cloud.

In this study, we suggest a system to build the monitoring model for compressed natural gas (CNG) stations, operated in only non-stationary mod es, and perform the real-time mon-itoring and the abnormality diagnosis using principal component analysis (PCA) that is suitable for processing large amounts of multi-dimensional data among mu ltivariate statistical analysis methods. We build the model by the calculation of the new characteristic variables, called as the major components, finding the factors representing the trend of process operation, or a combina-tion of variables among 7 pressure sensor data and 5 temperature sensor data collected from a CNG station at every second. The real-time monitoring is performed reflecting the data of process operation measured in real-time against the built model. As a r esult of conducting the test of mon-itoring in order to improve the accuracy of the system and verification, all data in the normal operation were distinguished as normal. The cause of abnormality could be refined, when abnor-mality was detected successfully, by tracking the variables out of the score plot.Key words : fault detection, monitoring, diagnosis, principal component analysis (PCA), CNG station

This study aims to suggest risk management plan including safety measures through hazard iden-tification followed by consequence analysis in petrochemical plants. Consequence analysis was performed through practical release scenario by using PHAST RISK(ver. 6.7) software in the propylene recovery proc-ess(PRP). As results, consequences by fire or explosion accidents in the depropanizer zone, deethanizer zone and heat pump zone were relatively larger than other else zones among six process zones in the PRP. In the case of jet fire, it is recommendable not to install residence building within 200 m of the process zone. Additionally, process zones having large inventory or high pressure must be prevented from accidents and required to estab-lish quick response against accidents. Key words : consequence analysis, fire, explosion, propylene recovery process, PHAST RISK 1) I. 서 론 에너지 산업의 급속한 발전에 따라 석유화학공장은 시설이 복잡하고, 다양화되고 있으며, 특히 다양한 종류의 유해물질을 대량으로 취급하고 있다 . 또한 † Corresponding author:kimto@mju.ac.kr Copyright ⓒ 2014 by The Korean Institute of Gas

Fire detection system is used for detection and alarm-generation of danger in case of fire. Most fire detection systems being used these days often malfunction from false positive and false neg-ative errors. To improve detection reliability, an integrated fire detection algorithm using multi-senor information of heat, smoke and carbon monoxide detectors is suggested, then built and tested using the LabVIEW environment. Simulated using sensor measurement data offered by National Institute of Standards and Technology (NIST), possibility of reducing false positive and false negative errors is verified.Key words : fire detection, LabVIEW, test bed, multi-sensor information, false positive error, false negative error 1) I. 서 론 최근 백화점, 대형 지하상가, 공공건물 등은 건축비용 상의 문제로 점차 고층화와 고밀도화가 되고 있으며, 이로 인해 재해가 발생할 경우에는 큰 피해를 초래하게 된다. 2011년도 국내 화재현황을 살펴보면, Fig. 1과 같이 부주의로 인한 화재가 16015건(36.5%)으로 가장 많고, 다음으로 전기적 요인으로 인한 화재가 10793 † Corresponding author:dongil@mju.ac.kr Copyright ⓒ 2012 by The Korean Institute of Gas

Systematic safety research by Korea Government has been made to enhance the safety of CNG (compressed natural gas) vehicles since the burst of compressed cylinder of an urban bus in August 9, 2010. This article summarizes some major activities to ensure the safety of CNG vehicles, which covers review of regulation, safety management system including standard of inspection and certification, and training program of inspectors and car mechanics. Specifically, the followings were reviewed; type of CNG cylinder, location of CNG cylinder, material and type of fuel line and vent line, modification of pipeline connection, installation of gas detector, installation of emergency shutdown valve, installation of protecting cover for cylinder, obligations for CNG vehicle filling station. improving periodical inspection, routine test on gas vehicles, training program for engaged in gas vehicles, and designation of safety manager for CNG bus company. This paper suggests how to improve safety of CNG vehicles as a result of review of above mentioned check items.Key words : CNG vehicles, safety improvement, regulation, safety management

For a methanol separation column of the BPA (Bisphenol A) plant, HAZOP (hazard and oper-ability) assessment was performed and damage ranges were predicted from the accident scenarios for the fire and the explosion. As a result, the damage range of the jet fire was 20 m in the case of rupture of the discharge pipe (50 mm diameter) of safety valve, and that of the flash fire was 267 m in the case of catastrophic rupture. Also, the damage ranges of the unconfined vapor cloud explosion (UVCE) for the rupture of the discharge pipe and for the catastrophic rupture were 22 m and 542 m, respectively. For the worst case of release scenarios, safety measures were suggested as follows: the pressure instruments, which can detect abnormal rise of the in-ternal pressure in the methanol separation column, should be installed by the 2 out of 3 voting method in the top section of the column. Through the detection, the instuments should simultaneously shut down the control and the emergency shut-off valves. Key words : HAZOP (hazard and operability), risk assessment, fire and explosion accidents, safety meas-ures, methanol separation column, BPA (Bisphenol A)

In this paper, an analytical model of a cantilever beam having a midpoint load is considered for structural optimization and design. This involves creation of the geometry through a parametric study of all design variables. For this purpose, the optimization of the cantilever beam was elaborated in order to find the optimum geometry which minimizes its volume eventually for minimum weight by FEM (finite element method) analysis. Such geometry can be obtained by different combinations of width and height, so that the beam may have the same cross-sectional area, yet different dynamic behavior. So for optimum safe design, besides minimum volume it should have minimum vibration as well. In order to predict vibration, different dynamic analyses were performed simultaneously to identify the resonant frequencies and mode shapes belonging to the lowest three modes of vibration. Next, by introducing damping effects, the tip displacement and bending stress at the fixed end was evaluated under dynamic loads of varying frequency. Investigation of the results clearly shows that only structural analysis is not enough to predict the optimum values of dimension for safe design it must be aided by dynamic analysis as well.

Risk-based inspection (RBI) is a inspection technique suggesting inspection plan, such as inspection interval and inspection method, of the pressurized facilities based on its risk in the petrochemical, refinery and gas industries. Therefore, we can intensively and cost-effectively maintain, repair and manage the high-risk facilities through RBI technology. This paper reviews RBI technology, such as principle and implemental procedure of RBI, management of risks and facilities and return of investment through RBI, RBI technology at present and its application in domestic industries. In addition, some improvement directions of RBI are also proposed.

As a way to propose a method for the establishment of practical damage-minimizing plan for chemical plants, the release scenario was established by using API-581 BRD and the effect zone was estimated by the KS-RBI program supporting the quantitative cause analysis. And the risk assessment was performed. As a result, we found that to minimize the damage of a chemical plant, it is effective to use four release hole diameters (small, medium, large and rupture) and release time estimated according to the classes of detection and isolation systems. In addition, it can be safely said that through appling the damage areas considering weighted average by failure frequency and worst-case simultaneously, industrial sites can come up with the effective emergency response plan. Key words : damage-minimizing plan, effect zone, risk assessment, API-581, KS-RBI program, emergency response plan † Ⅰ. 서 론 화학공업은 고도의 기술집약적인 장치산업으로, 생산기술의 발전과 더불어 시설이 대규모화, 고속 † 주저자:kimto@mju.ac.kr화, 그리고 복잡화되고 있을 뿐만 아니라 유해․위험성이 큰 화학물질의 취급량이 증가되고 있다[1,2]. 따라서 최근에는 설비의 자동화, 안전설계, 안전설비 설치, 비상조치계획 수립 등을 통하여 사고위험을 최소화 하려는 노력이 꾸준히 진행되고 있다. 그러나 설비의 노후화, 조작자 실수, 기계적인 고장 등으로 인하여 화재 , 폭발독성물질의 누출 등과 같은 KIGAS Vol. 15, No. 2, April, 2011(Journal of the Korean Institute of Gas)

The interest about new and renewable energy is increasing to reduce the burden of problems by depletion of fossil fuels and air pollutions. For example, LNG/CNG and LPG are expected to be replaced, especially in transportation use, by HCNG mixture and DME-LPG mixture, respectively. Because these new energies are still flammable gases, it is not inherently safe from the explosion. In this research, the quantitative risk analysis for using alternative mixtures in existing recharging facilities has been studied by using three types of explosion models (TNT equivalency model, PHAST and CFD-based FLACS) to manage the risk effectively. The differences of results by models were compared against, and the practical ways of when and how to use these models were suggested. It was also predicted that conventional gas filling stations would be converted as new energy stations without additional explosion risk.