최근 철도 주변에서 엄청난 양의 폐 콘크리트 침목이 적재 되어 있음을 쉽게 발견될 수 있다. 이는 열차에서 떨어진 금속가루 및 기름 때문에 폐 침목이 환경 유해물로 분류되기 때문이다. 보통 폐 콘크리트 침목은 50MPa 수준의 고강도 콘크리트로 되어 있어, 이를 활용하면 양질의 순환골재를 확보할 수 있다. Yang 등과 Kim 등은 순환골재에 붙어있는 구모르타르(RM)를 콘크리트 배합에 필요한 신모르타르(NM)의 일부로 간주하는 수정 등가모르타르체적(EMV) 배합법을 제안한 바 있다. 순환골재를 사용한 기존 배합법에서는 콘크리트 탄성계수의 저감 및 건조수축의 증가를 가져온 반면 수정 EMV 배합법에서는 천연골재를 사용한 기준 콘크리트에 비해 동등한 물성을 확보함을 보여주었다. 본 연구를 통해 위의 두 가지 배합법에 의해 제작된 콘크리트의 열팽창계수 실험을 수행하였다. EMV 배합법에 의해 제작된 순환골재 콘크리트의 열팽창계수가 기존 배합법에 의해 제작된 순환골재 콘크리트보다 작게 나옴을 보여 주었다. AASHTO-TP60 실험방법을 이용하여 10∼50℃의 범위에서 SUS304(열팽창계수 18.3m/m/℃)를 보정시편으로 사용하였다.

The fast pyrolysis of biomass (larch) in a circulating fluidized bed pyrolyzer was performed and the physico-chemical characteristics of biocrude-oil was investigated. Standard sand was used for fluidizing material and various reaction temperatures from 400℃ to 550℃ was applied. Wood (larch) sample was examined thorough proximate analysis and thermogravimetric analysis (TGA). From the results of the sample test, thermal decomposition characteristics of wood (larch) was investigated. Various analyses were carried out to determine the physicochemical properties of biocrude-oil such as Higher heating value (HHV), water content, viscosity, ash content and microscopic anaysis. The maximum biocrude-oil yield was 49.9wt.% at 550℃. At this temperature, HHV and water content were 4562.0 kcal/kg and 13.8wt.%, respectively. From the study results, wood (larch) has potential as an alternative energy source.

The development of renewable energy is currently strongly required to address environmental problems such as global warming. In particular, biomass is highlighted due to its advantages. When using biomass as an energy source, the conversion process is essential. Fast pyrolysis, which is a thermochemical conversion method, is a known method of producing bio-oil. Therefore, various studies were conducted with fast pyrolysis. Most studies were conducted under a lab-scale process. Hence, scaling up is required for commercialization. However, it is difficult to find studies that address the process analysis, even though this is essential for developing a scaled-up plant. Hence, the present study carries out the process analysis of biomass pyrolysis. The fast pyrolysis system includes a biomass feeder, fast pyrolyzer, cyclone, condenser, and electrostatic precipitator (ESP). A two-stage, semi-global reaction mechanism was applied to simulate the fast pyrolysis reaction and a circulating fluidized bed reactor was selected as the fast pyrolyzer. All the equipment in the process was modeled based on heat and mass balance equations. In this study, process analysis was conducted with various reaction temperatures and residence times. The two-stage, semi-global reaction mechanism for circulating fluidized-bed reactor can be applied to simulate a scaled-up plant.

화석연료의 고갈문제와 더불어 지구온난화 등의 환경문제에 대한 대응방안으로 전 세계적으로 지속가능한 에너지자원의 확보에 대한 필요성과 관심이 높아지고 있다. 중국, 인도 등의 국가에서 경제 성장을 위한 화석연료 의존도가 계속 높아지고 있다. 그러나 화석연료는 가격의 변동이 심하고, 한정된 매장량을 지니기 때문에 지나친 화석연료의 사용은 환경적으로 심각한 악영향을 미칠 수 있다. 바이오매스 및 폐자원을 활용하여 에너지를 생산하는 바이오에너지 분야는 최근 각광받는 신재생 에너지 분야 중 하나이다. 바이오에너지는 바이오매스, 폐자원으로부터 전환된 에너지 사용 시 발생되는 이산화탄소가 순환을 통하여 바이오매스의 성장에 다시 쓰이게 되므로 탄소중립적인 친환경 에너지이며 바이오매스의 경작, 재배를 통하여 지속적으로 생산 할 수 있다는 장점을 가진다. 바이오매스는 열분해, 가스화, 연소 등의 열화학적 분해공정을 통하여 더욱 가치있는 에너지의 형태로 활용 가능하며, 그 중 급속열분해 공정은 무산소 조건, 약 500℃의 반응온도, 2초 이하의 짧은 기체체류시간을 반응조건으로 하여 생산된 타르를 응축과정을 통해 액상 생성물인 바이오원유로 회수하는 공정이며 바이오원유의 회수율을 가장 높일 수 있는 공정이다. 바이오오일의 수율 및 성상은 급속열분해 운전조건에 따라 영향을 받으며 그 중 반응온도가 가장 중요한 인자이다. 따라서 본 연구에서는 낙엽송 톱밥을 원료로 하여 400 - 550℃로 반응온도를 변화시켜가며 바이오원유를 생산하고 생산된 바이오원유의 수율 및 다양한 물리화학적 분석(고위발열량, 수분함량, 점도, pH 등)을 통하여 그 특성을 파악하는 연구를 진행하였다.

In this study the AWS was installed in three areas to analyze creation and characteristics of local wind circulation through observation. According to the result, in night time when mountain wind is well developed showed temperature in A area located in Dalbigol valley and B area adjacent with the valley was lower than C area located in the lowland of the center of city by 1.5∼4℃. The wind speed was also shown two times stronger than C area. In addition, in terms of wind direction, A and B areas showed east wind consistently according to topographic shapes of Dalbigol valley with high altitude and residential sites of lowland with low altitude. Although the C area didn’t show big changes in wind direction due to the effects of city structures, east wind is often seen so mountain wind from Dalbigol valley is found to have an effect at least. Through the analysis of temperature, wind speed, and wind direction, nigh time showed relatively cold mountain wind blew following Dalbigol valley, throughout residential sites and to the center of city with lowland. During the daytime, the temperature in the city with lowland and residential sites is constantly higher than A area located in Dalbigol valley, and strong wind speed following Dalbigol valley, and three areas have 200∼300° of main wind direction, so west valley wind throughout the city with lowland and following Dalbigol is clearly formed.

How to plan the energy system is one of the keys for constructing the Environment -Friendly City. For this reason, a great number of surveys for utilizing unused energy have conducted by a planner. In regard to unused energy, the heat from incineration plants classify as a unused energy having high-exergy-energy. From this point of view, It is studied about the plant systems providing heat to district heating & cooling(D.H.C) and producing electric power. It is divided four system models as system I (10K [kgf/cm2] vapor as outlet of boiler, supply for 10K vapor and return to 60℃ as supply condition of district heating), system Ⅱ (30 K vapor as outlet of boiler, supply for 5K vapor and return to 60℃ as supply condition of district heating), system Ⅲ (30 K vapor as outlet of boiler, supply for 85℃ hot water and return to 60℃ as supply condition of district heating), system Ⅳ (30 K vapor as outlet of boiler, supply for 47℃ hot water and return to 40℃ as supply condition of district heating). The results from the upper condition of four system, System Ⅱ got a proper on economical benefits and system Ⅳ calculated as benefiting on energy saving effects, and suggest indifference curve as the total evaluation method of both economical benefits and energy saving.

An one dimensional atmosphere-canopy-soil interaction model is developed to estimate of the heat budget parameter in the atmospheric boundary layer. The canopy model is composed of the three balance equations of energy, temperature, moisture at ground surface and canopy layer with three independent variables of T_f(foliage temperature), T_g(ground temperature), and q_g(ground specific humidity). The model was verified by comparative study with OSUID(Oregon State University One Dimensional Model) proved in HAPEX-MOBILHY experiment. Also we applied this model in two dimensional land-sea breeze circulation. According to the results of this study, surface characteristics considering canopy acted importantly upon the simulation of meso-scale circulation. The factors which used in the numerical experiment are as follows ; the change for a sort of soll(sand and peat), the change for shielding factor, and the change for a kind of vegetation.