• 설비공학논문집
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• 제19권1호
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• pp.51-59
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• 2007

The waste bunker usually consists of waste entrance zone and waste pit. In this paper, the distributions of air flow, $NH_3$ concentration and $H_2S$ concentration in a waste bunker were investigated to prevent an odor generated in a waste pit from dispersing to the waste entrance zone by numerical method. Four cases were considered such that 1) the waste incinerators is operated, 2) the waste incinerators is stopped, 3) the waste incinerator is operated and the direction of a supply diffuser is $45^{\circ}$ upward, 4) the waste incinerator is stopped and the direction of a supply diffuser is $45^{\circ}$ upward. In case of 1), the fresh air from the waste entrance zone is exhausted smoothly to the main exhaust grill of the waste pit. It means that an odor dispersion to the waste entrance zone will not occur. However in case of 2), the induction of fresh air is so small and the supply air with an odor in waste pit can flow to the waste entrance zone. Therefore, an odor will be dispersed to the waste entrance zone. This paper shows the solution that the supply diffuser with the direction of $45^{\circ}$ upward is chosen. As a result in case of 3) and 4), an odor dispersion to the waste entrance zone does not occurred and on odor is exhausted smoothly to the auxiliary exhaust grill.

• 한국유체기계학회 논문집
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• 제18권5호
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• pp.26-32
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• 2015

This paper describes performance evaluation of design parameters, air velocity inside a pipeline and pressure along a pipeline, using experimental measurements in an automated vacuum waste collection system. Automatic robot having six cameras is introduced to analyze the internal pipeline conditions whether waste accumulates at the bottom of the pipeline or not. Throughout the experimental measurements of the pipeline having the various shapes, it is found that pressure and internal air velocity linearly increase along the pipeline from a waste inlet to a waste collection station while air density decreases due to the air compression effect with high pressure. Although air velocity inside the pipeline at a waste inlet keeps design velocity range between 20 m/s and 30 m/s, it is noted that air velocity near the waste collection station exceeds maximum design velocity of 30 m/s. Pressure increase per unit length is changed from 17.6 Pa/m to 18.9 Pa/m, which depends on the air velocity inside the pipeline. From the investigation inside the pipeline with CCTV loaded on an automated robot, waste accumulated at the bottom of the pipeline is mainly found at the downstream of a circular curved pipe, an inclined pipe and a bended pipe.

• 설비공학논문집
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• 제5권1호
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• pp.18-26
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• 1993

The performance of the evaporation facility of low radioactive liquid waste is studied experimentally. The evaporation facility comprises storage pools, feeding pumps, evaporation units with 1,040 sheets of cloth and air handling units. As the results of this study, it is found that the evaporation rate increases as the waste feed rate increases, the relative humidity of induced air decreases, and the air velocity increases. The modified Dalton's evaporation equation derived from experimental data is $E_h=(0.0168+0.0141V){\Delta}H$. The optimum operating conditions of the evaporation facility are waste feed rate of $4.5./hr.m^2$ and air velocity of 1.47m/sec.

• Environmental Engineering Research
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• 제23권3호
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• pp.258-264
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• 2018

The objectives of this research were to 1) isolate and identify thermophilic bacteria for food waste treatment; 2) investigate the capability of food waste treatment using Bacillus species; and 3) develop air-dried Bacillus starters for food waste treatment. Five Bacillus species were isolated from food wastes and identified as Bacillus licheniformis (B. licheniformis) G1, Bacillus circulans C2, Bacillus subtilis (B. subtilis) E1, Bacillus vanillea F1, and Bacillus atrophaeus G2 based on 16S rDNA sequencing. Each identified Bacillus and the mixture of Bacillus species were cultivated in the standard food waste at $45^{\circ}C$ for 8 d. Changes in cell count, solid contents, and pH of the food waste were monitored during cultivation. Air-dried Bacillus cell powders were prepared using wheat flour and lactomil as excipients, and the cell count and survival rate were determined. The cell count of B. licheniformis G1 exhibited the highest number among the tested Bacillus (${\sim}10^8CFU/mL$). The greatest reduction in solid contents of food waste was achieved by B. subtilis E1 (22.6%). The mixture of B. licheniformis G1 and B. subtilis E1 exhibited a synergistic effect on the reduction of solid contents. Lactomil was determined as better excipient than wheat flour based on the greatest survival rate of 95%.

• 설비공학논문집
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• 제26권7호
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• pp.329-334
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• 2014

This study indicated the possibility of energy regeneration from waste coolant heat, by using thermoelectric generation integrated with heat pipe. The internal combustion engine rejects more than 60% wasteful energy to the atmosphere by heat. The thermoelectric generator has recently been studied, to convert the energy from engine waste heat into electricity. For coolant waste heat recovery, a thermoelectric generator was investigated, to find out the possibility of vehicular application. Performance characteristics were conducted with various test conditions of coolant temperature, coolant mass flow rate, air temperature, and air velocity, with the thermoelectric generator installed either horizontally or vertically. Experimental results show that the electric power and conversion efficiency increases according to the temperature difference between the hot and cold side of the thermoelectric generator, and the coolant flow rate of the hot side heat exchanger. Performance improvement can be expected by optimizing the heat pipe design.

• Design & Manufacturing
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• 제14권2호
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• pp.28-33
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• 2020

Recently, as the income level and quality of life have improved, the desire for a pleasant environment has increased, and a deodorization plan is required through thorough prevention and diffusion of odorous substances in waste treatment facilities recognized as hateful facilities, appropriate collection, and selection of the right prevention facilities. In this study, a waste disposal facility was modeled and computerized analysis for odor and ventilation analysis was conducted. Numerical analysis of the waste treatment facility was performed at the size of the actual plant. CATIA V5 R16 for numerical model generation and ANSYS FLUENT V.13 for general purpose flow analysis were used as analysis tools. The average air-age of the internal was 329 seconds, and the air-flow velocity was 0.384m/s. The odor diffusion analysis inside the underground pump room showed congestion-free air circulation through streamline distribution and air-age distribution. This satisfies the ASHRAE criteria. In addition, the results of diffusion analysis of odorous substances such as ammonia, hydrogen sulfide, methyl mercaptan and dimethyl sulfide were all expected to satisfy the regulatory standards. Particularly in the case of the waste loading area, the air-flow velocity was 0.297m/s, and the result of meeting the regulatory standards with 0.167ppm of ammonia, 0.00548ppm of hydrogen sulfide, 0.003ppm of methyl mercaptan, and 0.003ppm of dimethyl sulfide was found.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 춘계학술논문요약집
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• pp.237-238
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• 2017

• Design & Manufacturing
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• 제16권2호
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• pp.26-32
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• 2022

It is known that the fluidized bed incinerator, which is the subject of analysis, shows excellent performance in heat and mass transfer due to excellent mixing and contact performance between fluidized sand and fuel, and also shows relatively good combustion characteristics thanks to good mixing and long residence time for low-grade fuels. have. In this study, air flow analysis is performed to understand the characteristics of co-firing of sludge, waste oil and solid waste in the fluidized bed incinerator, flow characteristics of flue gas, and discharge characteristics of pollutants.The fluidized bed incinerator subject to analysis is a facility that incinerates factory waste and general household waste together with sludge, with a processing capacity of 32 tons/day. to be. In addition, the operation method was designed for continuous operation for 24 hours. As a result, it can be seen that the lower combustion air and the introduced secondary air are changed to a strong turbulence and swirl flow form and exit through the outlet while rotating inside the freeboard layer. The homogeneous one-way flow form before reaching the secondary air nozzle has very high diffusivity with the high-speed jet flow of the nozzle.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.238-244
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• 2005

This study performs the pilot-plant experiments to evaluate the effect of the oxygen enrichment on the co-incineration of municipal solid waste and organic sludge from a wastewater treatment facility. The design capacity of the stoker-type incinerator pilot-plant is 150 kg/h. Combustion chamber temperatures were measured as well as the stack gas concentrations, i.e., NOx, CO, and the residual oxygen. The maximum ratio of organic sludge waste to the total waste input is 30%. Also the oxygen-enriched air with 23% of oxygen in supplied air is used for stable combustion. As the co-incineration ratio of the sludge increased up to 30% of the total waste input, the primary and the secondary combustion chamber temperature was decreased $to900^{\circ}C$ (primary combustion chamber), $750^{\circ}C$(secondary combustion chamber), respectively, approximately $200^{\circ}C$ below the incineration temperature of the domestic waste only (primary: $1,100^{\circ}C$, secondary: $950^{\circ}C$). However, if the supplied air was enriched to 22% oxygen content in air, the incinerator temperature was high enough to burn the waste mixture with 30% sludge, which has the heating value of 1,600 kcal/kg.

• 대한설비공학회지:설비저널
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• 제15권4호
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• pp.362-371
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• 1986

In the normal Refrigeration process, the condensation heat of refrigerant s not been used because of its low-temperature waste heat. To recover the condensation waste heat of R-12 refrigerator, a drying and hot water system was designed and experimented. The results obtained were summarized as follows: 1. As the temperature a temosphere was increased, the temperature of discharge gas of compressor was increased. And the temperature was $80-84^{\circ}C$ for air condensing type and was $68-71^{\circ}C$ for water condensing type during summer. 2. The condensation waste heat could be obtained up to $50-55^{\circ}C$ of drying heat-source and Hot water in summer. In this case, recovered rate was about $73\%$. And the more temperature of drying Heat-source and Hot water were increased, the more a recovered rate were decreased. 3. When comparing drying characteristics of Agro-products in dryer of waste heat utilization and Hot air, there was no quality difference in products. But drying time of the former was 3 Hours longer than the latter. 4. The condensation waste heat of compressor could be applied into the drying of marine products, the predrying of agro-products and making hot water. And showed high possibility of the waste heat using in low-temperature storage.