• Journal of Biosystems Engineering
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• v.8 no.2
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• pp.49-61
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• 1983

U shape multitube heat exchanger was equipped in the flue to recover the exhaust heat from the boiler system. The fluids of the exhaust heat recovery equipment were the flue gas as the hot fluid, and the water as the cold fluid. The flow geometry of the fluids was cross flow - two pass, the hot fluid being mixed and the cold fluid unmixed. The results of the theoretical and the experimental analysis and the economic evaluation are summarized as follows. 1) The heat exchanger effectiveness and the temperature efficiency of the hot fluid were about 35% when the fuel consumption rate was 140 - 150 L/15min. The temperature efficiency for the cold fluid ranged from 3.0% to 4.5%. The insulation efficiency ranged from 85% to 98%, which was better than the KS air preheater insulation efficiency of 90%. 2) The relationship between the fuel consumption rate, F, and the outlet temperature, $T_{h2}$, of the flue gas from the heat exchanger was $T_{h2}$ = 0.927F + 110. In order to prevent the low temperature corrosion from the coagulation of $SO_3$, it is necessary to maintain the fuel consumption rate above 82 L/15min. 3) The ratio of the exhaust heat from the boiler system to the total energy consumption was about 14.5%. With the installation of the exhaust heat recovery equipment, the energy recovery ratio to the exhaust heat was about 25%. Accordingly, about 3.6% of the total fuel consumption was estimated to be saved. 4) Economic analysis indicated that the installation of the exhaust heat recovery equipment was feasible to save the energy, because the capital reocvery period was only 10 months when the fuel consumption rate was 80 L/15min. 4 months when it was 160 L/15min. 5) Based on the theoretical and the experimental analysis, it was estimated to save the energy of about 18 million Won per year, if four heat exchangers are installed in a factory. 6) A further study is recommended to identify the relationship among the flow rate of the exhaust gas, the size of the heat exchanger and the capacity of the air preheater. For a maximum heat recovery from the exhaust gas an automatic control system is required to control the flow rate of the cold fluid depending on the boiler load.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.553-556
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• 2009

This research aims at the recovery of valuable resource and more efficient waste treatment through solving the problem of pyrolysis technique. At first, in order to raise the economical efficiency, the low temperature pyrolysis experiment was carried out at the temperature of $450^{\circ}C$, which is lower than the common pyrolysis temperature area ($500{\sim}1000^{\circ}C$). We could lower the reaction temperature and reduce the reaction time by using catalyst. Also we used indirect heat for the purpose of maintaining favorable anoxic condition. As a result, we could raise the recovery rate of the valuable copper and synthetic fuel oil. Furthermore, the by-products and flue gas could be treated more effectively as well. The flue gas passed through two stage neutralization tank, so that dioxin hardly occurs and other environment items are controlled fairly well to the environmental standard. Throughout this study, we produced the low temperature pyrolysis equipment (GTPK-001) as mentioned above, and we found out that the technique can be commercialized economically as well as environmentally friendly.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.160-165
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• 1998

The Joint curing barns for flue-cured tobacco is a favorite with the tobacco farmers in Korea. However, most of farmer utilizing the joint curing barns indicated many problems such as high temperature and noise in the working room and a dry of cured leaves in the storage room. A structure of Joint curing barns has been modified to meet the needs of tobacco farmers. Compared with the unimproved joint curing barns, the improved one showed that the noise of workshop decreased about 7.7～10.8db, the amount of $CO_2$ decreased 40～50ppm in a working room and 80～100ppm in a machine room. Ammonia gas decreased 0.29mg/㎥ and the temperature of a working room dropped about 2.1～3.5$^{\circ}C$. The amount of air flow in a working room increased 23.2% at a site being 2m away from the entrance and 30.8% at a center. The inner temperature of the improved storage room showed that maximum temperature dropped about 3$^{\circ}C$, minimum temperature was high about 2$^{\circ}C$. The highest relative humidity was low 6%, the lowest one increased high about 10% when compared with the unimproved joint curing barns.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.449-457
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• 1996

The main purpose of this study was to investigate sulfur dioxide removal performance of flue gas desulfurization system utilizing a Spray Absorption/Drying Reactor. In this system, the size of droplets was considered the most significant factor and tested using a PDA system. Lime slurry flow rate, operating temperature, calcium/sulfur (Ca/S) ratio and applied air pressure were selected as major operation variables and tested/analyzed in terms of system performance. The results are as follows. 1. The $SO_2$ removal efficiencies were 49%, 74%, 85% for Ca$(OH)_2$ slurry flow rate of 10, 20, 30 ml/min, which implies that the increase of slurry flow rate improves removal efficiency. The optimum slurry flow rate in this study was, however, considered 20 ml/min because of constraints of system troubles and absorbent utilization. 2. As Ca/S ratio increased, $SO_2$ removal efficiency was observed to increase. 3. As air pressure, at the atomizing nozzole, increased from 3 to 5 $kg/cm^2, SO_2$ removal efficiency increased from 74% to 80%, because of droplet size reduction due to pressure increase during atomizing process and the increase of surface area, helping mass transfer between gas and liquid phase.

• Membrane Journal
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• v.15 no.2
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• pp.147-156
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• 2005

It is well-known that polyethersulfone (PES) has high $CO_2$ selectivity over $N_2\;(or\;CH_4)$ and excellent pressure resistance of $CO_2$ plasticization among muy commercialized engineering plastics[1-4]. Asymmetric PES hollow fiber membranes for flue gas separation were developed by dry-wet spinning technique. The dope solution consists of PES, NMP and acetone. Water and water/NMP mixtures are used in outer and inner coagulants, respectively. Gas permeation rate (i.e., permeance) and $CO_2/N_2$ selectivity were measured with pure gas, respectively and the micro-structure of hollow fiber membranes was characterized by scanning electron microscopy. The effects of polymer concentration, ratio of NMP to acetone, length of air gap, evaporation condition and silicone coating were investigated on the $CO_2/N_2$ separation properties of the hollow fibers. Optimized PES hollow fiber membranes exhibited high permeance of $25\~50$ GPU and $CO_2/N_2$ selectivity of $30\~40$ at room temperature and have the apparent skin layer thickness of about $0.1\;{\mu}m$. The developed PES hollow fiber membranes, would be a good candidate suitable for the flue gas separation process.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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• pp.359-364
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• 2004

For the development of high efficiency and low emission combustion systems, high temperature air combustion technology has been tested by utilizing preheated air over 1100 K and exhaust gas recirculation. In this system, combustion air is diluted with large amount of recirculated exhaust gases, such that the oxygen concentration is relatively low in the reaction zone, leading to low flame temperature. Since, the temperature fluctuations and sound emissions from the flame are small and flame luminosity is low, the combustion mode is expected to be flameless or mild combustion. Experiment was performed to investigate the turbulent flame structure and NO$_x$ emission characteristics in the high temperature air combustion focused on coflowing jet diffusion flames which has a fundamental structure of many practical combustion systems. The effect of turbulence has also been evaluated by installing perforated plate in the oxidizer inlet nozzle. LPG was used as a fuel. Results showed that even though NO$_x$ emission is sensitive to the combustion air temperature, the present high temperature air combustion system produce low NO$_x$ emission because it is operated in low oxygen concentration condition by the high exhaust gas recirculation.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.654-661
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• 2000

Area of greenhouse increases rapidly up to 45,265ha by the year of 1998 in Korea. Hot air heater with light oil combustion is the most common heater for greenhouse heating in the winter season. However, exhaust gas heat discharged to atmosphere through chimney reaches up to 10~20% of total heat of the oil combusted in the furnace. In order to recapture the heat of this exhaust gas and to recycle for greenhouse heating, the heat pipe type exhaust heat recovery system was manufactured and tested in this experiment. The exhaust heat recovery system was made for space heating in the greenhouse. The system consisted of a heat exchanger made of heat pipes, ${\emptyset}15.88{\times}600mm$ located in the rectangular box of $600{\times}550{\times}330mm$, a blower and air ducts. The rectangular box was divided by two compartments where hot chamber exposed to exhaust gas in which heat pipes could pick up the heat of exhaust gas, and by evaporation of the heat transfer medium in the pipes it carries the heat to the cold compartment, then the blower moves the heat to greenhouse. The number of heat pipe was 60, calculated considering the heat exchange amount between flue gas and heat transfer capacity of heat pipe. The working fluid of heat pipe was acetone because acetone is known for its excellent heat transfer capacity. The system was attached to the exhaust gas path. According to the performance test it could recover 53,809 to 74,613kJ/hr depending on the inlet air temperature of 12 to $-12^{circ}C$ respectively when air flow rate $1,100\textrm{m}^3/hr$. The exhaust gas temperature left the heat exchanger dropped to $100^{circ}C$ from $270^{circ}C$ by the heat exchange between the air and the flue gas, the temperature difference was collected by the air and the warm air temperature was about $60^{circ}C$ at the air flow rate of $1,100\textrm{m}^3/hr$. This heat pipe type exhaust heat recovery system can reduce fuel cost by 10% annually according to the economic analysis.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.4 no.1
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• pp.6-17
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• 1975

For a periodic variation of the flue gas temperature the heat conduction through the Ondol floor was analysized. Also the heat loss to the ground was estimated. The floor thermal capacity, as a function of the floor thickness, has strong influence on the time lag of the temperature variation. It is an important design parameter for intermittent heating. Even for the steady periodic variation, there was significant heat loss to the ground below the Ondol floor.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.44-52
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• 2024

This study presents a novel approach to hydrogen production by biogas from organic waste without CO₂ removal. A process model was developed to reduce the costs associated with biogas pretreatment and purification processes. Through optimization of heat exchange networks, the simulation aimed to minimize process costs, maximizing hydrogen production and flue gas temperature. The results reveal that the most efficient process model maximizes the flue gas temperature while following the constraint of the number of heat exchangers. These findings hold promise for contributing to the expansion of "Biogas-to-clean hydrogen" energy conversion technology.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.125.1-125.1
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• 2011

$CO_2$ separation from a flue gas by using the gas hydrate technology was suggested by Kang et al. They reported phase equilibrium conditions of mixed gases composed of $CO_2$ and N2 with THF as a thermodynamic promoter. In this study, we reported the phase equilibrium conditions of a mixed gas which had a realistic composition of the blast furnace gas (BFG) emitted from the steel-making process. The phase equilibrium measurements were done by using the "continuous" QCM method, and the results demonstrate that this method is efficient and as accurate as the conventional temperature search method.