• Clean Technology
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• v.28 no.4
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• pp.316-322
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• 2022

The flow pattern at the inlet of the catalyst layer in a selective catalytic reduction (SCR) system is one of the key parameters influencing the performance of the denitrification process. In the curved diffusing parts between the ammonia injection grids and the catalyst layers, guide vanes are installed to improve flow uniformity. In the present study, a numerical simulation has been performed to investigate the effect of the geometrical configuration of the guide vanes on the aerodynamic characteristics of a denitrification facility. This application has been made to the existing SCR process in a large-scaled coal-fired power plant. The flow domain to be solved covers the whole region of the flow passages from the exit of the ammonia injection gun to the exit of the catalyst layers. ANSYS-Fluent was used to calculate the three-dimensional steady viscous flow fields with the proper turbulence model fitted to the flow characteristics. The root mean square of velocity and the pressure drop inside the flow passages were chosen as the key performance parameters. Four types of guides vanes were proposed to improve the flow quality compared to the current configuration. The numerical results showed that the type 4 configuration was the most effective at improving the aerodynamic performance in terms of flow uniformity and pressure loss.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.77-86
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• 2021

In this study, to use as basic data for the organic waste resource energy incentive system, the energy efficiency is evaluated through the mass balance and energy balance calculation results of the anaerobic digester where food waste, food waste leachate and various organic wastes are treated. As a result of the mass balance analysis for 11 biogasification facilities, it was confirmed that 21.1% of process water and 25.7% of tap water were input in large amounts, excluding organic waste. Accordingly, it accounted for 87.6% of the total effluent of linked treated water. In addition, considering that 15.7% of the total input volume is converted to biogas and the average total solids (TS) is 22%, an average material conversion rate of 75% was confirmed. As a result of the energy balance analysis, the energy conversion rate was confirmed to be 78.5% on average by analyzing the biogas calorific value compared to the potential energy of the influent. The average biogas production efficiency including external energy sources for biogas production was 69.4%, and the biogas plant efficiency to which unused effluent energy was applied was 58.9% on average.

• Korean Journal of Environment and Ecology
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• v.36 no.1
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• pp.30-55
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• 2022

This study conducted a flora survey in the areas of Mt. Sambong (282m) and Mt. Jaung (263m), located in Paju-si, Gyeonggi-do. A total of 434 taxa, including 6 forms, 34 varieties, 11 subspecies, 383 species, 271 genera, and 94 families, were surveyed in the two mountain areas. The ferns were identified as 24 taxa from 10 families, the gymnosperms as 8 taxa from 2 families, the dicotyledonous plants as 322 taxa from 73 families, and the monocotyledonous plants as 80 taxa from 9 families. Five taxa, including Salix koriyanagi, Cimicifuga heracleifolia, Forsythia koreana, Paulownia coreana, and Hemerocallis hakuunensi, were identified as the Korean endemic plants. Eight taxa, including Cimicifuga heracleifolia, Tylophora floribunda, and Iris minutiaurea as Vulnerable species, andAristolochia contorta, Viola diamantiaca, Lithospermum erythrorhizon, Lilium distichum, andArisaema heterophyllumas Least Concern species, were designated as rare and endangered plants designated by the Korea Forest Service. The invasive alien plants were 40 taxa, including Rumex crispus, Phytolacca americana, Cerastium glomeratum, Silene armeria, Chenopodium album, Chenopodium ficifolium, Magnolia obovata, Potentilla supina, Amorpha fruticosa, Medicago sativa, Robinia pseudoacacia, Trifolium repens, Euphorbia supina, Hibiscus trionum, and Oenothera biennisaccounting for 9.2 percent of the 434 taxa of the surveyed plants. As this area is a mountainous area close to settlement facilities, it is believed that ecological preservation measures and measures of specialized plants should be implemented.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.2
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• pp.59-66
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• 2022

The purpose of this study was to suggest the landscaping repair work classification, the standard for securing the independence of and establishing the scope of landscaping repair works. Standard construction specifications currently specify the landscaping repair work classification around the planting construction, while standard work estimate does not include the field of landscaping. The landscaping construction specifications and the standard work estimate in the construction industry should be, however, applied, so it is difficult to specifically understand what is the landscaping repair work classification in the cultural heritage industry. From 1961 to 1980, not only the tree planting but also a variety of landscaping facilities had been specified as the landscaping repair works, and it was found that all of these work classifications are established as the landscaping repair work classifications in the construction industry. A total of 20 work classifications were verified by comprehensively arranging those specified in notices of tender for working drawing services for cultural heritages during three years, from 2018 to 2020, except for those for the maintenance and Dancheong of architectures, plant protection and conservation. All 20 work classifications corresponded to the landscaping work classifications in the construction industry. On the basis of the landscaping work classifications in the construction industry, this study divided the landscaping repair work classifications into site-building and shaping, planting work, facility construction, paving work, ecological landscape architectural construction and vegetation maintenance, by considering the specialty of cultural heritage space.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.339-347
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• 2023

Dissolved organic matter (DOM) is a key component in the biogeochemical cycling in freshwater ecosystem. However, it has been rarely explored, particularly complex river watershed dominated by natural and anthropogenic sources, such as various effluent facility and livestock. The current research developed a new analytical method for TOC/TN (Total Organic Carbon/Total Nitrogen) stable isotope ratio, and distinguish DOM source using stable isotope value (δ¹³C-DOC) and spectroscopic indices (fluorescence index [FI] and biological index [BIX]). The TOC/TN-IR/MS analytical system was optimized and precision and accuracy were secured using two international standards (IAEA-600 Caffein, IAEA-CH-6 Sucrose). As a result of controlling the instrumental conditions to enable TOC stable isotope analysis even in low-concentration environmental samples (<1 mgC L^-1), the minimum detection limit was improved. The 12 potential DOM source were collected from watershed, which includes top-soils, groundwater, plant group (fallen leaves, riparian plants, suspended algae) and effluent group (pig and cow livestock, agricultural land, urban, industry facility, swine facility and wastewater treatment facilities). As a result of comparing characteristics between 12 sources using spectroscopic indices and δ¹³C-DOC values, it were divided into four groups according to their characteristics as a respective DOM sources. The current study established the TOC/TN stable isotope analyses system for the first time in Korea, and found that spectroscopic indices and δ¹³C-DOC are very useful tool to trace the origin of organic matter in the aquatic environments through library database.

• Industry Promotion Research
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• v.9 no.2
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• pp.37-44
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• 2024

This study selected the worst-case scenario for fireball and vapor cloud explosion (VCE) of a styrene monomer storage tank installed in a petrochemical production plant and performed damage prediction and accident impact analysis. The range of influence of radiant heat and overpressure due to fireball and vapor VCE during the abnormal polymerization reaction of styrene monomer, the main component of the mixed residue oil storage tank, was quantitatively analyzed by applying the e-CA accident damage prediction program. The damage impact areas of radiant heat and explosion overpressure are analyzed to have a maximum radius of 1,150m and 626m, respectively. People within 1,150m of radiant heat of 4kW/m2 may have their skin swell when exposed to it for 20 seconds. In buildings within 626m, where an explosion overpressure of 21kPa is applied, steel structures may be damaged and separated from the foundation, and people may suffer physical injuries. In the event of a fire, explosion or leak, determine the risk standards such as the degree of risk and acceptability to workers in the work place, nearby residents, or surrounding facilities due to radiant heat or overpressure, identify the hazards and risks of the materials handled, and establish an emergency response system. It is expected that it will be helpful in establishing measures to minimize damage to workplaces through improvement and investment activities.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.75-84
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• 2023

Many developing countries face challenges in estimating long-term discharge due to the lack of hydrological data for water supply planning, making it difficult to establish a rational water supply plan for decision-making on water distribution. The study area, the Bandung region in Indonesia, is experiencing rapid urbanization and population concentration, leading to a severe shortage of freshwater. The absence of water reservoir prediction methods has resulted in a water supply rate of approximately 20%. In this study, we aimed to propose an approach for predicting water reservoirs in developing countries by analyzing water safety and potential water supply using the MODSIM (Modified SIMYLD) network model. To assess the suitability of the MODSIM model, we applied the unit hydrograph method to calculate long-term discharge based on 19 years of discharge data (2002-2020) from the Pataruman observation station. The analysis confirmed alignment with the existing monthly optimal operation curve. The analysis of power plant capacity revealed a difference of approximately 0.30% to 0.50%, and the water intake safety at the Pataruman point showed 1.64% for Q95% flow and 0.47% for Q355 flow higher. Operational efficiency, compared to the existing reservoir optimal operation curve, was measured at around 1%, confirming the potential of using the MODSIM network model for water supply evaluation and the need for water supply facilities.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.209-222
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• 2024

The Earth Pressure Balance (EPB) shield Tunnel Boring Machine (TBM) is widely used for underground tunnel construction for its advantages, such as eliminating the need for additional facilities compared to the slurry shield TBM, which requires Slurry Treatment Plant (STP). During EPB shield TBM excavation, a soil conditioning technique is employed to enhance the physical properties of the excavated soil by injecting additives, thus broadening the range of applicable ground conditions to EPB shield TBMs. This study explored the use of xanthan gum, a type of biopolymer, as an alternative to the commonly used polymer additive. Biopolymers, derived from biological sources, are fully biodegradable. In contrast to traditional polymers such as polyacrylic acid, which contain environmentally harmful components, xanthan gum is gaining attention as an eco-friendly material due to its minimal toxicity and environmental impact. Test conditions with similar workability were established through slump tests, and the rheological characteristics were assessed using a laboratory pressurized vane shear test apparatus. The experiments demonstrated that, despite exhibiting similar workability, the peak strength in the flow curve decreased with increasing the content of xanthan gum. Consequently, a correlation between the xanthan gum content and peak strength was established. Replacing the traditional polymers with xanthan gum could enable stable EPB shield TBM operation by reducing equipment load, in addition to offering environmental benefits.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2875-2880
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• 2024

The development of nuclear power plants is in three phases. The first phase is a consideration before the decision on the NPP construction program is approved, the second phase is the preparatory work for making contracts and preparing for the construction of NPP after the NPP construction policy is approved, and the third phase is contracting, licensing and building the first NPP. As a volcanically active country, Indonesia contains over 130 active volcanoes that are part of the Pacific Ring of Fire. The volcanic aspect is one of the safety factors considered while deciding the location of an NPP. Research on the potential of natural external risks to the determination of nuclear power plants in Indonesia, including the volcanic aspect, has been conducted based on the safety reference or safety guide of the IAEA and the Nuclear Energy Regulatory Body (BAPETEN) Regulation. Due to technological advancements, safety needs have evolved so the existing Indonesia National Standard (SNI) must be updated to comply with BAPETEN regulations. The substance in SNI 18-2034-1990 relating to volcanic features seems less relevant in actual conditions, given that more complete and exact criteria for determining a site guarantee the safety and health of residents and surrounding the environment site. The study intends to conduct a gap analysis of volcanic issues in SNI and volcanic regulations. The method used is identification requirements for volcanic aspects in SNI 18-2034-1990 about Determining Site of Nuclear Reactor Guidance with BAPETEN Chairman Regulation (BCR) number 4 of 2018 about Nuclear Installation Site Evaluation Safety Provisions and BCR number 5 of 2015 about Evaluation of Nuclear Installation Sites for Volcanic Aspects, and analysis uses a qualitative method of inductive techniques. The outcome of this research applies to suggesting a revision of SNI number 18-2034-1990, especially the volcanic aspect.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.687-692
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• 2024

The energy crisis is emerging as a serious problem around the world. In the case of Korea, there is great interest in energy efficiency research related to industrial complexes, which use more than 53% of total energy and account for more than 45% of greenhouse gas emissions in Korea. One of the studies is a study on saving energy through sharing facilities between factories using the same utility in an industrial complex called a virtual energy network plant and through transactions between energy producing and demand factories. In such energy-saving research, data collection is very important because there are various uses for data, such as analysis and prediction. However, existing systems had several shortcomings in reliably collecting time series data. In this study, we propose an intelligent IIoT platform to improve it. The intelligent IIoT platform includes a preprocessing system to identify abnormal data and process it in a timely manner, classifies abnormal and missing data, and presents interpolation techniques to maintain stable time series data. Additionally, time series data collection is streamlined through database optimization. This paper contributes to increasing data usability in the industrial environment through stable data collection and rapid problem response, and contributes to reducing the burden of data collection and optimizing monitoring load by introducing a variety of chatbot notification systems.