• 한국연소학회지
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• 제15권2호
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• pp.41-49
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• 2010

Various coals from many countries around the world have been used for pulverized coal boiler in power plants in Korea. In this study, the gasification reactivities of various coal chars with $CO_2$ were investigated. Carbon conversion was measured using a real time gas analyzer with NDIR CO/$CO_2$ sensor. In a lab scale furnace, each coal sample was devolatilized at $950^{\circ}C$ in nitrogen atmosphere and became coal char and then further heated up to reach to a desired temperature. Each char was then gasified with $CO_2$ under isothermal conditions. The reactivities of coal chars were investigated at different temperatures. The shrinking core model (SCM) and volume reaction model(VRM) were used to interpret the experiment data. It was found that the SCM and VRM could describe well the experimental results within the carbon conversion of 0-0.98. The gasification rates for various coals were very different. The gasification rate for any coal increased as the volatile matter content increased.

• 대한기계학회논문집B
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• 제33권2호
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• pp.133-140
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• 2009

A fast-response $CO_2$ analyzer has been developed for measuring the $CO_2$ concentration during transient condition of a SI engine. The analyzer consists of the non-dispersive infrared absorption method, electrical chopping system and water cooling system. The analyzer has good repeatability, linearity and permissible drift characteristic. Besides, it showed 18ms of a response to measure the $CO_2$ concentration. The fast-response $CO_2$ analyzer was applied to a single cylinder SI engine and the $CO_2$ emission was examined during engine start. Simultaneously, the standard exhaust gas analyzer, which has slow response time, was used for confirming the accuracy of the exhaust gas analysis using the fast-response $CO_2$ analyzer. The developed analyzer showed much faster responsive characteristic than that of a standard analyzer and made cycle by cycle exhaust gas analysis possible. The transient engine operating characteristics will be estimated from the $CO_2$ concentration of engine-out emissions and engine operating variables.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3079-3084
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• 2008

A fast response $CO_2$ analyzer has been developed for measuring the $CO_2$ concentration during transient condition of SI engine. The analyzer is based on the non-dispersive infrared absorption technique, electrical chopping system and water cooling system. The analyzer has good repeatability, linearity and permissible drift characteristic. Besides, it has 18ms with a response to measure the $CO_2$ concentration. The fast response $CO_2$ analyzer was applied to single cylinder SI engine and the $CO_2$ emission was examined during engine start. Simultaneously, the standard exhaust gas analyzer, which has slow response time, was used for considering the engine-out $CO_2$ characteristic. The developed analyzer showed much faster responsive characteristic than that of a standard analyzer and made cycle by cycle exhaust gas analysis possible. The transient engine operating characteristics will be estimated and the transient behaviors on engine-out emission and performance will be improved.

• 한국안전학회지
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• 제30권1호
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• pp.111-118
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• 2015

In this study, we carried out the emissions analysis of CO and $non-CO_2$ for the age-classes of various pine trees(Pinus koraiensis, Pinus densiflora, Pinus rigida Mill., Pinus thunbergii Parl.) to estimate of emission factors of the crown layer and surface layer in the forest fire. We used the thermal characteristic analyzer cone heater and NDIR analyzer in order to measure amount of emission. As a result, the major emissions of Pinus koraiensis were $CO_2$ and $CH_4$ and that of Pinus thunbergii Parl. was only CO. The major emissions of the most of pine trees were NO and $N_2O$. The $CO_2$ emission of Pinus thunbergii Parl. was the highest about as $7.26{\times}10^{-2}{\sim}1.63{\times}10^{-1}g$ and next came Pinus densiflora, Pinus koraiensis, Pinus rigida Mill.. And the CO emission of Pinus thunbergii Parl. was about $5.14{\times}10^{-3}{\sim}6.58{\times}10^{-3}g$ and followed by Pinus densiflora, Pinus koraiensis, Pinus rigida Mill.. The emissions of $CH_4$, NO, and $N_2O$ showed small differences between species and the emission of $CH_4$ was $8.37{\times}10^{-5}{\sim}2.55{\times}10^{-4}g$, and NO was $6.65{\times}10^{-5}{\sim}2.0{\times}10^{-4}g$ and $N_2O$ was $1.42{\times}10^{-4}{\sim}2.09{\times}10^{-3}g$ in all species. Particularly, the emission of Pinus thunbergii Parl. was the highest in all pine trees except $CH_4$.

• 센서학회지
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• 제13권4호
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• pp.258-263
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• 2004

In this study, we carried out a basic study for the development of optical transcutaneous $pCO_{2}$ gas sensor and analyzer using non-invasive method. The basic principle of $pCO_{2}$ measurement is adapted Beer lambert's law and embodied the system using NDIR method. This measuring system was composed of a IR lamp, a optical filter, a optical reaction chamber, pyroelectric sensor and a signal process. We measured $EtCO_{2}'s$ concentration in basis step instead of $pCO_{2}$ gas that can collect by inflicting heat in outer skin. We minimize the size of optical reaction chamber which takes up the largest volume, to make the portable sensor. We made optical reaction chamber in Si wafer using MEMS technology and the optical reaction chamber was shortened to 2 mm and we carried out an experiment. When we injected the $EtCO_{2}$ to the inside of the optical reaction chamber, we could confirm change of 4.6 mV. The system response time was within 2 second that is fairly fast.

• 한국대기환경학회지
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• 제22권1호
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• pp.107-116
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• 2006

The main purpose of this study is to develop the greenhouse gas emission factor for power plant using bituminous coal. The power plant is a major source of greenhouse gases among the sectors of fossil fuel combustion, thus information of its emission factors is very essential to the establishment of control strategies for the greenhouse gas emissions. These emission factors derived in this study were compared with those of U. S. EPA, AGO and CCL. The $CO_{2}$ concentrations in the flue gas were measured using NDIR analyser and the GC-FID with a methanizer. The amount of carbon (C) and hydrogen (H) in fuel was measured using an elemental analyzer. Calorific values of fuel were also measured using a calorimeter. Caloric value of bituminous coal used in the power plants were 5,957 (as received basis), 6,591 (air-dried basis) and 6,960 kcal/kg (dry basis). Our estimates of carbon emission factors were lower than those of IPCC. The CO2 emission factors for the power plants using bituminous coal were estimated to be 0.791 Mg/MWh (by carbon contents and caloric value of the fuel) and 0.771 Mg/MWh (by $CO_{2}$ concentration of the flue gas). The $CO_{2}$ emission factors estimated in this study were $3.4\sim 5.4\%$ and $4.4\sim 6.7\%$ lower than those of CCL (2003) and U. S. EPA (2002).

• 한국가스학회지
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• 제12권4호
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• pp.63-68
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• 2008

본 논문은 적외선 센서의 광 강도 및 효율을 증가시키기 위해 새로운 오목한 반사 벽면(curved mirror surface)과 기존의 수직 반사 벽면(vertical mirror surface)구조와의 모의해석 및 실험 결과에 대해 기술하였다. 모의해석 결과 수직 반사 벽면을 사용했을 때 적외선 센서 필터 표면에 도달하는 광의 분포는 타원 형상으로 적외선 센서 표면에 도달함을 볼 수 있고, 오목한 반사 벽면을 사용하는 경우에는 광이 원형상으로 집광되는 것을 볼 수 있었다. 따라서 초기 평행광의 면적보다 작은 면적으로 집광됨으로 인해 단위면적당 광 강도는 향상되고, 이에 따라 광학적 센서의 출력전압은 향상될 것이라 예측되었다. 이 모의해석을 근간으로 하여 $25^{\circ}C$, 45%R.H.에서 이산화탄소를 0 ppm에서 2500 ppm까지 250 ppm 간격으로 주입시켰을 때, 오목한 반사 벽면의 광 공동이 수직 반사 벽면의 광 공동보다 출력전압이 약 200 mV 증가하였다.

• 한국물환경학회지
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• 제24권6호
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• pp.682-689
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• 2008

The purpose of this study was to find out the variation between molecular size distribution (MSD) of natural organic matter (NOM) in raw waters after different water treatment processes like conventional process (coagulation, flocculation, filtration) followed by advanced oxidation process (ozonation, GAC adsorption). The MSD of NOM of Suji pilot plant were determined by Liquid Chromatography-Organic Carbon Detection (LC-OCD) which is a kine of high-performance size-exclusion chromatography (HPSEC) with nondispersive infrared (NDIR) detector and $UV_{254}$ detector. Five distinct fractions were generally separated from water samples with the Toyopearl HW-50S column, using 28 mmol phosphate buffer at pH 6.58 as an eluent. Large and intermediate humic fractions were the most dominant fractions in surface water. High molecular weight (HMW) matter was clearly easier to remove in coagulation and clarification than low molecular weight (LMW) matter. Water treatment processes removed the two largest fractions almost completely shifting the MSD towards smaller molecular size in DW. No more distinct variation of MSD was observed by ozone process after sand filtration but the SUVA value were obviously reduced during increase of the ozone doses. UVD results and HS-Diagram demonstrate that ozone induce not the variation of molecular size of humic substance but change the bond structure from aromatic rings or double bonds to single bond. Granular activated carbon (GAC) filtration removed 8~9% of organic compounds and showed better adsorption property for small MSD than large one.

• 한국가스학회지
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• 제18권2호
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• pp.48-54
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• 2014

본 논문에서는 알코올 측정용 센서의 광학적 특성 향상을 위한 고유한 광학적 구조를 제안하였으며, 모의해석을 실시하였다. 광 도파관은 한쪽에 공통초점을 갖는 두 개의 타원형 광 도파관으로 구성되었으며, 각 광 도파관의 서로 다른 초점에 적외선 광원과 적외선 센서를 갖는다. 두 타원형 광 도파관의 각도가 30도에서 90도로 증가시켰을 때, 단위면적당 최대 입사광량은 $2.23{\times}10^6W/m^2$에서 $5.74{\times}10^5W/m^2$로 감소하였다. 그러나 조사 빔의 반지름은 1.86 mm로 최소값을 나타내었고, 전체 입사 에너지는 90도 각도를 갖는 구조와 비교하여 약 10 % 작은 값을 보였다. 모의해석 결과로부터 본 논문에 제안한 구조는 긴 흡수파장을 갖는 광학적 가스센서의 감도향상에 기여할 것으로 판단된다.

• 분석과학
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• 제13권2호
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• pp.222-228
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• 2000

비분산 적외선 방식에 의한 대기 중 일산화 탄소 측정용 검출기를 제작하고, 감도 및 안정성을 조사하였다. 검출 감도를 향상시키기 위하여 동일 흡수셀 내에 3개의 반사거울을 장착하여 셀 안에서의 빛의 통과거리가 증가되도록 설계하였다. 50cm 길이의 셀 안에서 빛의 통과거리를 16m까지 늘릴 수 있도록 컴퓨터 모사에 의해 반사거울의 곡률반경 및 곡률중심, 셀 안에서의 위치 등을 산출하여 셀을 제작하였다. 빛의 경로와 광학적 특성은 모의 셀 안에서 laser beam alignment에 의해 확인하였다. 투과광의 검출에는 광전도성 PbSe센서를 사용하였으며, 센서소자는 열전냉각방식에 의해 냉각하였다. 제작된 일산화 탄소 검출기의 검출한계와 스팬 드리프트는 각각 0.24ppm과 0.03ppm(v/v)이었다.