• 에너지공학
• /
• 제25권4호
• /
• pp.214-225
• /
• 2016

목재 바이오매스를 이용한 가스화 공정은 고열량의 합성가스를 통해 알콜류, SNG 등 다양한 에너지 자원으로 변환시킴으로써 자원의 재순환에 기여할 수 있으며, $CO_2$ 등의 온실가스를 감소시킴으로써 지구온난화 방지에 기여할 수 있다. 본 연구에서는 이중유동층 가스화기에 목재 바이오매스를 투입하여 가스화기의 최적운전 조건을 도출하고, SNG 생산효율을 검증함으로써 이중유동층 가스화기에 대한 국내 상용화 기반을 마련하고자 하였다. 목재 바이오매스에 대한 가스화기의 최적 운전조건 도출 결과, 운전온도 $826^{\circ}C$에서 Steam 투입량 1,334g/hr, Air 투입량 5.56L/min일 때 탄소전환율이 81%로 확인되었으며, SNG 생산을 위한 $CH_4$가스 농도를 확인한 결과, 92%로 나타났다.

• 한국환경복원기술학회지
• /
• 제10권5호
• /
• pp.31-39
• /
• 2007

This study was carried out to evaluation the recycled waste soils from construction site for planting soil. For this purpose, the concentrations of polluted materials and the physico-chemical properties were measured at recycled soil samples of an industrial waste treating company in the Metropolitan landfill area. The concentrations of polluted materials did not exceed to the standard critical levels of soil pollution in all analyzed items. The measures of the samples soil texture (loamy sand), bulk density (1.09~1.32g/$cm^3$), saturated hydraulic conductivity ($1.6{\times}10^{-3}{\sim}1.8{\times}10^{-3}$cm/sec), solid phase distribution (0.4~0.5$m^3/m^3$), porosity (0.5~0.6$m^3/m^3$), Ex. $K^+$ (1.0~1.2cmol/kg), Ex. $Mg^{2+}$ (0.2~0.6cmol/kg) were identified as not worse than those of conventional planting soil. But the sample soils have serious problems for planting soil such as high levels of pH (9.6~11.5), EC (0.78~1.84ds/m) and Ex. $Ca^{2+}$ (25.6~34.5cmol/kg), low level of organic matter (0.2~0.3%). It is required to improve pH, EC and Ex. $Ca^{2+}$ of sample soils. Consequently, the results suggested a high potential of recycling of the wastes soils for planting soil.

• Computers and Concrete
• /
• 제19권4호
• /
• pp.419-427
• /
• 2017

With the rising global environmental awareness on energy saving and carbon reduction, as well as the environmental transition and natural disasters resulted from the greenhouse effect, waste resources should be efficiently used to save environmental space and achieve environmental protection principle of "sustainable development and recycling". This study used recycled cement mortar and adopted the volumetric method for experimental design, which replaced cement (0%, 10%, 20%, 30%) with recycled materials (fly ash, slag, glass powder) to test compressive strength and ultrasonic pulse velocity (UPV). The hyperbolic function for nonlinear multivariate regression analysis was used to build prediction models, in order to study the effect of different recycled material addition levels (the function of $R_m$(F, S, G) was used and be a representative of the content of recycled materials, such as fly ash, slag and glass) on the compressive strength and UPV of cement mortar. The calculated results are in accordance with laboratory-measured data, which are the mortar compressive strength and UPV of various mix proportions. From the comparison between the prediction analysis values and test results, the coefficient of determination $R^2$ and MAPE (mean absolute percentage error) value of compressive strength are 0.970-0.988 and 5.57-8.84%, respectively. Furthermore, the $R^2$ and MAPE values for UPV are 0.960-0.987 and 1.52-1.74%, respectively. All of the $R^2$ and MAPE values are closely to 1.0 and less than 10%, respectively. Thus, the prediction models established in this study have excellent predictive ability of compressive strength and UPV for recycled materials applied in cement mortar.

• Geomechanics and Engineering
• /
• 제12권3호
• /
• pp.523-539
• /
• 2017

Clay soils are typical for their swelling properties upon absorption of water during rains and development of cracks during summer time owing to the profile desorption of water through the inter-connected soil pores by water vapour diffusion leading to evaporation. This type of unstable soil phenomenon by and large poses a serious threat to the strength and stability of structures when rest on such type of soils. Even as lime and cement are extensively used for stabilization of clay soils it has become imperative to find relatively cheaper alternative materials to bring out the desired properties within the clay soil domain. In the present era of catastrophic environmental degradation as a side effect to modernized manufacturing processes, industrialization and urbanization the creative idea would be treating the waste products in a beneficial way for reuse and recycling. Bottom ash and ecosand are construed as a waste product from cement industry. An optimal combination of bottom ash-eco sand can be thought of as a viable alternative to stabilize the clay soils by means of an effective dispersion dynamics associated with the inter connected network of pore spaces. A CATIA model was created and imported to ANSYS Fluent to study the dispersion dynamics. Ion migration from the bottom ash-ecosand pile was facilitated through natural formation of cracks in clay soil subjected to atmospheric conditions. Treated samples collected at different curing days from inner and outer zones at different depths were tested for, plasticity index, Unconfined Compressive Strength (UCS), free swell index, water content, Cation Exchange Capacity (CEC), pH and ion concentration to show the effectiveness of the method in improving the clay soil.

• Journal of Construction Engineering and Project Management
• /
• 제2권4호
• /
• pp.20-24
• /
• 2012

Construction while being an economic activity that provides facilities and infrastructure, it is beneficial to man in some aspects and detrimental in others. There have been environmental concerns related to construction activities globally which mainly focus on atmospheric emissions, depletion of natural resources and energy issues. This study was carried out to assess the impacts of construction activities on the environment in Iganga Municipality and to propose measures for their mitigation. The methodology included: review of relevant literature, observations of the general environmental effects of construction activities, focus groups and a survey conducted among construction industry role players to determine their perceptions and opinions regarding environmental impact of construction activities. The collected data was presented in tabular form and analysed by description of responses to questions. The study revealed that forests were the most greatly degraded due to high demand of timber for construction followed by wetlands degradation. The findings of this study will be useful to architects, designers and builders in order to carefully design buildings and other infrastructure that are environmentally friendly and sustainable. Construction materials and their mode of acquisition are harmful threats to the environment. There is need to reduce the consumption of these materials through recycling and reusing wastes to reduce on waste generation, use of virgin materials and the subsequent waste of energy used in new material production.

• 한국유기농업학회지
• /
• 제20권4호
• /
• pp.475-490
• /
• 2012

Since 1997, Korean Ministry of Knowledge Economy and Ministry of Environment have established data on some 400 basic raw and subsidiary materials and process like energy, petro-chemical, steel, cement, glass, paper, construction materials, transportation, recycling and disposal etc by initiating establishment of LCI database. Regarding agriculture, Rural Development Administration has conducted establishment of LCI database for major farm products like rice, barley, beans, cabbage and radish etc from 2009, and released that they would establish LCI database for 50 items until 2020 later on. The domestic LCI database for seeds, seedling, agrochemical, inorganic, fertilizer and organic fertilizer etc is only at initial stage of establishment, so overseas LCI databases are brought and being used. However, since the domestic and overseas natural environments differ, they fall behind in reliability. Therefore, this study has the purpose to select organic farming materials, survey the production process for various types of organic farming materials and establish LCI database for the effects of greenhouse gas emitted by each crop during the process. As for selecting methods, in this study organic farming materials were selected in the method of direct observation of material and bottom-up method a survey method with focus on the organic farming materials admitted into rice production. For the basic unit of carbon emission amount by the production of 1kg of organic farming material, the software PASS 4.1.1 developed by Korea Accreditation Board under Ministry of Knowledge Economy was used. The study had the goal to ultimately provide basic unit to calculate carbon emission amount in executing many institutions like goal management system and carbon performance display system etc in agricultural sector to be conducted later on. As a result, emission basic units per 1kg of production were calculated to be 0.04968kg-$CO_2$ for oystershells, 0.004692kg-$CO_2$ for expanded rice hull, and 1.029kg-$CO_2$ for bordeaux mixture liquid.

• 한국농공학회논문집
• /
• 제57권1호
• /
• pp.99-109
• /
• 2015

In the construction industry, the interest for recycling aggregates is rising as more people demand for alternatives due to lack of supply of natural aggregates and environmental problems. However, in order for recycled aggregates to be used in infrastructures, stability and other factors need to be verified. Therefore, the objective of this study is to analyze the sensitivity of soil properties to secure slope safety according to various heights of embankment when bottom ash and dredged soil mixture is applied in the embankment. In most cases, all heights were safe for the slide for the embankment whether the water level is full or sudden draw down. The result of the sensitivity analysis revealed that the unit weight of embankments is highest among all factors to be considered. However, the sensitivity of the unit weight became smaller and the sensitivity of the friction angle of embankments increased with the height of embankments. The sensitivity of factors of core materials is very small because the core has weaker physical properties than those of the embankment. The effect of the height for each factor is different for each slope and water levels. The sensitivity of the unit weight of embankments is most affected when the height is 60m in the upstream slope. To conclude, bottom ash and dredged soil mixture can be applied in the embankment and different factors must be considered in different scale because the sensitivity depends highly on the height of embankments.

• 한국구조물진단유지관리공학회 논문집
• /
• 제19권4호
• /
• pp.101-108
• /
• 2015

급격한 산업화와 삶의 질의 변화로 인해 생산된 고밀도 폐유리의 양은 꾸준히 증가하고 있으나 대부분 재활용되지 못하고 있다. 특히 고밀도 폐유리의 경우 불법적으로 처리되거나 매립되는 실정이다. 한편, 원전구조물의 안전성 확보를 위해 차폐 성능이 우수한 재료가 사회적으로 요구되고 있다. 콘크리트는 가장 많이 사용되고 있는 건설재료이며, 많은 양의 자원들이 콘크리트를 생산하기 위해 사용되고 있다. 따라서 고밀도 폐유리를 차폐 콘크리트 재료로 재활용할 수 있는 방안에 대한 연구가 요구되어진다. 본 연구에서는 고밀도 폐유리를 차폐 콘크리트 잔골재로의 적용가능성을 평가하였다. 결과에 따르면, 폐유리를 혼입한 모르타르의 경우, 일반 모르타르에 비하여 단위용적질량이 증가하여 차폐 성능 개선이 가능할 것으로 판단된다. 폐유리 혼입에 의해 강도는 감소하는 것으로 나타났으며, 세척의 경우보다 비세척의 경우에 강도 발현이 유리한 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
• /
• pp.937-940
• /
• 2008

골재자원의 부족과 폐기콘크리트의 증가로 인하여 순환골재사용의 필요성이 증가되고 있다. 그러나 순환골재의 건조수축으로 인한 균열등과 같은 문제점이 지적되어 이에 대한 연구가 요구되고 있다. 따라서 본 연구에서는 순환골재에 관한 연구의 일환으로 순환잔골재를 활용한 섬유 보강 콘크리트의 소성 및 초기 건조수축균열을 판상-링형구속수축시험 및 모의부재 옥외폭로시험을 통하여 측정하였다. 그 결과 판상-링형구속수축시험의 경우 순환잔골재를 사용한 콘크리트가 천연 잔골재보다 균열발생이 크게 나타났으며 섬유혼입의 경우 무혼입보다 높은 균열 저감성능을 나타내었다. 모의부재 실험에 있어서도 판상-링형구속수축시험과 유사하게 순환잔골재를 사용한 콘크리트가 균열발생이 큰 것으로 나타났으며 섬유 혼입의 경우 높은 저감 성능을 나타내었다.

• 한국건축시공학회지
• /
• 제15권2호
• /
• pp.193-199
• /
• 2015

최근, 콘크리트 산업에서는 $CO_2$ 배출량감소등 환경문제와 함께 부존자원의 고갈대책도 중요한 문제점으로 제기되어, 이를 동시에 해결하기 위하여 각종 산업부산물이나 산업폐기물을 콘크리트용 자원으로 재이용하는 방법이 연구되고 있다. 본 연구는 고로슬래그 미분말(BS)과 순환잔골재(RFA) 혼합 모르타르를 기반으로 하여 BS의 잠재수경성 반응을 탈황석고(FGD)와 보통포틀랜드 시멘트(OPC)의 자극반응으로 추가 활성화시킴으로써 일반 강도영역까지의 모르타르 활용성을 검토하고자 하였다. 결과적으로, BS에 FGD 10%, OPC 30%를 치환하고 RFA를 사용할 경우 OPC만을 사용하는 플레인 모르타르의 80%정도인 보통강도모르타르가 발휘되었지만 실용적인 측면에서 유동성적으로 플로치를 동일하게 유지하는 물-결합재를 낮춰 주게 된다면 더욱 플레인 강도영역에 근접할 수 있을 것으로 사료된다.