• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.587-594
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• 2010

Hydrogen is an alternative fuel for the future energy which can reduce pollutants and greenhouse gases. Synthesis gas has played an important role of synthesizing the valuable chemical compounds, for example methanol, DME and GTL chemicals. Renewable biomass feedstocks can be potentially used for fuel and chemicals. Current thermal processing techniques such as fast pyrolysis, slow pyrolysis, and gasification tend to generate products with a large slate of compounds. Lignocellulose feedstocks such as forest residues are promising for the production of bio-oil and synthesis gas. Pyrolysis and gasification was investigated using thermogravimetric analyzer (TGA) and bubbling fluidized bed gasification reactor to utilize forest woody biomass. Most of the materials decomposed between $320^{\circ}C$ and $380^{\circ}C$ at heating rates of $5{\sim}20^{\circ}C$/min in thermogravimetric analysis. Bubbling fluidized bed reactor was used to study gasification characteristics, and the effects of reaction temperature, residence time and feedstocks on gas yields and selectivities were investigated. With increasing temperature from $750^{\circ}C$ to $850^{\circ}C$, the yield of char decreased, whereas the yield of gas increased. The gaseous products consisted of mostly CO, $CO_2$, $H_2$ and a small fraction of $C_1-C_4$ hydrocarbons.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.219-225
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• 2010

Optimal grinding condition was examined by changing only the size of screen opening with fixing other factors to produce coal fines of particle sizes required for circulating fluidized bed gasifier. At least 85 wt% of the coal particles should fall into the size range of 0.045~1.0 mm for efficient gasification. In this study, hammer mill was used to grind Chinese low rank lignite coal following grinding condition designed by Taguchi method. The analysis of signal to noise ratio showed that optimum grinding condition for the gasifier was 3 mm in primary screen size and 1.3 mm in secondary screen size on the 95% level of significance.

• Food Science and Preservation
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• v.15 no.3
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• pp.332-339
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• 2008

This study was performed to investigate the sorption characteristics and shelf-life of coated ascorbic acid Stability of ascorbic acid, which oxidizes easily during storage and processing, was achieved by applying a fluidized bed coating using Zein-DP and HPMC-FCC as covering materials. The monolayer moisture content calculated using the GAB equation showed a higher level of significance than when calculated using the BET equation. The fit to the isotherm curve was in the order of Halsey, Caurie, Oswin and Khun. The equilibrium relative humidity prediction model was established in terms of time and water activity, it had higher significance. The stability of the coated ascoribic acid during storage was investigated in terms of radical-scavenging activity, which decreased with increasing time of storage and was more affected at higher storage temperatures. The quality reduction rate constant (k) was calculated by a first-order reaction rate. The reaction rate constant increased with increasing storage temperature. The shelf-life of Zein-DP-coated ascorbic acid was estimated to be 45.83 days at 20C and 63.19 days at 10C, and the shelf-life for HPMC-FCC-coated ascorbic acid was estimated to be 28.84 days at 20C and 36.14 days at 10, the ascorbic acid was 24.52 days at $20^{\circ}C$ and 27.22 days at $10^{\circ}C$, respectively. Therefore, the fluidized bed coating effectively increased the stability of ascorbic acid.

• Food Science and Preservation
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• v.14 no.4
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• pp.364-368
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• 2007

The purpose of this study was to improve the stability and the processing property of vitamin C. Vitamin C was coated according to particle size(80-100 mesh, 100-140 mesh) and mixing ratio(1:1.6, 1:2.5, 1:3(w/w)) with coating solution(8% Zein-DP, 6% HPMC-FCC), and then the quality characteristics of fluidized bed micro coated vitamin C were investigated. The coating efficiency and the thickness of coating film were higher in $80{\sim}100$ mesh particle than in $100{\sim}140$ mesh particles, and coating efficiency was decreased as the coating material was increased. The distribution range of particle was more narrow in mixing ratio of 1:3(w/w) than in the other. DPPH radical scavenging activity was not affected by the particle size and the mixing ratio. There was no difference between the coating materials in terms of the quality characteristics. The optimum coating condition for fluidized bed micro-coating of vitamin C powder was selected as the particle size of $80{\sim}100$ mesh and the mixing ratio with coating solution of 1:3(w/w).

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.333-348
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• 2020

The present review dealt with the state-of-art on utilization of coal bottom ash in cement-based concrete and mortar. Two types of bottom ashes generated from pulverized coal combustion and circulating fluidized-bed combustion systems have been considered. The production process, chemical and physical characteristics of both ashes, and the methodology of utilization in various cement composites are summarized. The effect of bottom ash on various properties of concrete, such as workability, strength, and durability, were reviewed from the literature. In addition, the environmental and economic aspects of utilizing bottom ash in concrete are analyzed to explore the perspectives of bottom ash utilization, and through this, the future of the utilization was considered. The effect of bottom ash on the performance of concrete and mortar was greatly depended on the condition, pretreatment, and processing of the ash. Additional processing such as crushing might contribute to stimulating the utilization in this field. In particular, if economic support is possible in terms of policy, utilization rate is expected to be improved.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.60-67
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• 2021

This study presented techno-economic analysis of a 500 MWe oxy-coal power plant with CO2 capture. The power plant included a circulating fluidized-bed (CFB), ultra-supercritical steam turbine, flue gas conditioning (FGC), air separation unit (ASU), and CO2 processing unit (CPU). The dry flue gas recirculation (FGR) was used to control the combustion temperature of CFB. One FGR heat exchanger, one heat exchanger for N2 stream exiting ASU, and a heat recovery from CPU compressor were considered to enhance heat efficiency. The decrease in the temperature difference (ΔT) of the FGR heat exchanger that means the increase in heat recovery from flue gas enhanced the electricity and exergy efficiencies. The annual cost including the FGR heat exchanger and FGC cooling water was minimized at ΔT = 10 ℃, where the electricity efficiency, total capital cost, total production cost, and return on investment were 39%, 1371 M$, 90 M$, and 7%/y, respectively.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.354-361
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• 2016

The purpose of this study was to prepare lightweight foamed concrete by mixing coal fly ash of circulating fluidized bed combustion(CFBC) with cement, and to develop uses for recycling by analyzing carbonation behavior resulting from a change in conditions for pressurized carbonation. For concrete, CFBC coal fly ash was mixed with Portland cement to the water-binder ratio of 0.5, and aging was applied at room temperature after 3 days of curing at $20^{\circ}C$, RH 60%. For carbonation, temperature was fixed at $60^{\circ}C$ and time at 1 h in the use of autoclave. Pressures were controlled to be $5kgf/cm^2$ and the supercritical condition of $80kgf/cm^2$, and gas compositions were employed as $CO_2$ 100% and $CO_2$ 15%+N2 85%. In the characteristics of produced lightweight concrete, the characteristics of lightweight foamed concrete resulting from carbonation reaction were affirmed through rate of weight change, carbonation depth test, air permeability, and processing analysis for the day 28 specimen. Based on these results, it is concluded that the present approach could provide a viable method for mass production of eco-friendly lightweight foamed concrete from CFBC coal fly ash stabilized by carbonation.

• Journal of Dairy Science and Biotechnology
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• v.37 no.4
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• pp.213-222
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• 2019

Milk and dairy products are the high value foods for the elderly population. In particular, fermented milk is the best source of calcium for people in the specific age group of over 79 years. It provides a good source of protein. Regular exercise and active lifestyle are recommended to slow down the muscle loss. However, exercising without proper nutrient intake is simply not sufficient at this age. Milk and dairy products provide the iron and protein content required for effective exercise-assisted growth. Milk nutrients have the advantage of being produced in various food forms, such as liquid, semi-solid, and powder types. Fat-soluble vitamins such as retinol and vitamin K can be encapsulated using various technologies for milk and dairy products. Using the encapsulation method, spray drying and fluidized-bed coating have been used for adding the micro-nutrients to the food. Microencapsulation technology is being applied in case of the fermented dairy products too. In particular, various wall materials are being developed to enhance the viability of probiotics. In the near future, advanced high-efficiency technologies that can effectively nourish the dairy products with nutrients will be developed to produce targeted high-nutrition value food for the elderly.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.3
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• pp.152-160
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• 2013

The purpose of this study is to enhance the mechanical strength of specimens containing fly ash from fluidized bed type boiler, which the recycling rate will be eventually increased. Specimens containing fly ash in a certain portion were made and aged for 3, 14, and 28 days. Specimens were carbonated under the supercritical condition at $40^{\circ}C$. The carbonation process under the supercritical condition was performed to enhance the mechanical property of specimens by filling the voids and cracks existing inside cement specimen with $CaCO_3$ reactants. The additional aging effect after the supercritical carbonation process on mechanical strength of specimens was also investigated by comparing the compressive strength with and without 7 day extra aging. Under the supercritical condition and additional 7 day aging specimens were very effective for enhancement of mechanical strength and compressive strength increased by 44 %.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.5
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• pp.254-259
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• 2012

The mechanical property enhancement was studied using fly ash produced from fluidized bed type boiler in power plant, which contains a lot of Ca component being used to carbonate for $CO_2$ fixation in the lightweight aggregates made of cement and some portion of fly ash as a cement substitution under the supercritical condition. Specimens having various fly ash substitution rates and curing periods were carbonated under the supercritical condition at $40^{\circ}C$. The weight change rate, carbonation rate by TG/DTA analysis, 1% Phenolphthalein test, specific gravity and mechanical compression strength test were performed to observe the mechanical property enhancement of the cemented materials after carbonation under the supercritical condition and to make sure those could be classified as lightweight aggregates having specific gravity under 2.0.