Characteristics of novel synthetic fuels using coal and sewage sludge impregnated bioliquid applying for a coal combustion system

Namkung, Hueon,Park, Ju-Hyoung,Lee, Young-Joo,Song, Gyu-Seob,Choi, Jong Won,Kim, Joeng-Geun,Park, Jun-Su,Um, Byung Hwan,Song, Kwang Ho,Park, Se-Joon,Choi, Young-Chan Elsevier 2017 Fuel processing technology Vol.167 No.-

<P><B>Abstract</B></P> <P>The application of biomass resources and sewage sludge is currently the most important issue in the field of coal combustion systems. The main drawback for operating a boiler system is its varied firing characteristics and low heating value. In this study, we have developed new synthetic fuels, namely hybrid sludge fuel (HSF), using coal and sewage sludge impregnated bioliquid (molasses) and evaluated their properties by comparison with conventional fuels. To prepare the HSF, it was treated in a carbonization system at 250°C. Depending on the van Krevelen diagram, the fuel quality of HSF was superior to that of raw bioliquid and sewage sludge. In addition, its fuel characteristic was similar to sub-bituminous and bituminous coal. Thermogravimetric analysis (TGA) indicated only a single-stage combustion pattern for HSF during non-isothermal heating. To clarify the unburned carbon (UBC) content, an ultimate analysis was conducted. The amount of UBC of the HSF was much more than that of sewage sludge, but less than that of coal. To investigate the surface hydrophobicity of HSF, Fourier transform infrared spectroscopy (FT-IR) analysis and a moisture re-adsorption test were carried out. The HSF possessed high hydrophobicity and presented a low moisture re-adsorption rate compared to conventional fuels.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The new synthetic fuel (HSF) using coal and sewage sludge impregnated bioliquid was investigated. </LI> <LI> HSF properties were similar to sub-bituminous and bituminous coal on the van Krevelen diagram. </LI> <LI> HSF showed single-stage combustion characteristics from the thermogravimetric analysis. </LI> <LI> HSF presented higher fuel reactivity in comparison with low reactivity coal. </LI> <LI> HSF had a higher hydrophobicity on the surface. </LI> </UL> </P>

Blending effect of sewage sludge and woody biomass into coal on combustion and ash agglomeration behavior

Namkung, Hueon,Lee, Young-Joo,Park, Ju-Hyoung,Song, Gyu-Seob,Choi, Jong Won,Choi, Young-Chan,Park, Se-Joon,Kim, Joeng-Geun Elsevier 2018 Fuel Vol.225 No.-

<P><B>Abstract</B></P> <P>The co-combustion of sewage sludge and woody biomass is a key issue in coal power plants. Different combustion and ash behaviors of sewage sludge and woody biomass cause unpredictable operating concerns. In this study, the combustion and ash agglomeration behavior of blended fuel of sewage sludge and woody biomass (BSW) were investigated while coal co-combusted with it. Thermogravimetric analysis (TGA) revealed that adding a high amount of BSW into the coal lowered volatilization, ignition, and burn-out temperature. The char combustion reactivity of coal differed from that of BSW. The shrinking core model (SCM) and volumetric reaction model (VRM) were used to fit the char combustion reactivity of coal and BSW. In the case of ash agglomeration behavior, BSW addition led to increasing particle agglomeration at fouling temperatures. In particular, phosphorus composition influenced particle growth, which was verified using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX) analysis. Furthermore, the ash mixture ratio of BSW and coal changed the intensity of the phosphorus-bearing mineral phase from X-ray diffraction (XRD) analysis, and finally influenced the melting temperature of the ash.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The combustion and ash agglomeration characteristics of coal and BSW mixture were investigated. </LI> <LI> Addition of BSW into the coal lowered the combustion temperature profiles during non-isothermal heating conditions. </LI> <LI> Carbon and reagent gas reaction occurred on exterior and interior of the particle during char combustion. </LI> <LI> BSW containing high phosphorus contents made a high agglomeration tendency and low melting mineral phase. </LI> </UL> </P>

탄산염 광물화 반응의 최적화를 위한 사문석 전처리 특성 연구

남궁훤(Hueon Namkung),장나형(Na-Hyung Jang),이준수(Joon-Soo Lee),허려화(Li-Hua Xu),김형택(Hyung-Teak Kim) 한국에너지기후변화학회 2008 에너지기후변화학회지 Vol.3 No.1

The carbonation reaction of the carbon dioxide and Serpentine in an aqueous have been recently studied. The assessment of the heat treatment was evaluated to be used widely. In this research it was studied to know characteristic of Serpentine through heat treatment. To use FT-IR found out whether the -OH group was removed or not and TGA confirmed weight loss of Serpentine. Also Serpentine was used in experiment less than ~38 ㎛ diameter. Serpentine was treated to improve reactivity at 650℃, for I hour, which was found as the best conditions of heat treatment.

Production and characterization of hybrid coal using sugar impurities extracted from pitch pine

Lee, Young-Joo,Namkung, Hueon,Park, Ju-Hyoung,Song, Gyu-Seob,Park, Se-Joon,Kim, Joeng-Geun,Choi, Jong-Won,Jeon, Chung-Hwan,Choi, Young-Chan Elsevier 2018 Applied thermal engineering Vol.145 No.-

<P><B>Abstract</B></P> <P>The main concerns of coal power plants are related to high thermal efficiency and biomass utilization for the reduction of CO<SUB>2</SUB> emissions. In this work, the fuel characteristics of a hybrid coal (HCK) impregnated by sugar impurities extracted from a lignocellulosic biomass were investigated. First, an optimized extraction condition for the sugar impurities was chosen among the various reaction temperatures and times using a hydrothermal pre-treatment (HTP) reactor. The extracted sugar impurities were consisted of 21.76 wt% glucan, 75.88 wt% XMG (xylan + mannan + galactan) and 2.36 wt% arabinan at the optimized reaction condition (190 °C and 30 min). 5 wt% sugar impurities based on the coal weight (dry basis) was used to prepare the HCK and the fuel characteristics were compared. According to the H/C and O/C ratios, raw coals were upgraded. In addition, the calorific value of the raw coals was enhanced by HCK production process. The HCKs had a low moisture re-adsorption rate in an excessive water immersion condition compared to the raw coals. To clarify the combustion behavior of the HCKs, thermogravimetric analysis (TGA) was carried out. The HCKs had a single-stage combustion pattern on the differential thermogravimetric (DTG) curve, even though they were composed of a coal and biomass resource. During the kinetic study of the raw coals and HCKs, a high reaction rate constant (<I>k</I>) and low activation energy (<I>Ea</I>) for the HCKs were identified compared to that of the raw coals.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We optimized the HTP based sugar extraction process from Pitch pine to show 50 wt% yield, which were 190 °C and 30 min. </LI> <LI> The sugar impurities consist of 21.8 wt% glucan, 75.9 wt% XMG and 2.3 wt% arabinan, respectively. </LI> <LI> The hybrid coal with the sugar impurities shows 5% higher heating value and 70% reduction of moisture re-adsorption. </LI> </UL> </P>

외환의 심리적 장벽과 통화옵션의 내재변동성

신동훈 ( Dong Hoon Shin ),김선현 ( Seon Hueon Kim ),김호준 ( Ho Joon Kim ),정대휘 ( Dae Hwi Jung ) 한국파생상품학회(구 한국선물학회) 2014 선물연구 Vol.22 No.2

이 논문은 원/달러, 유로/달러, 엔/달러 세 환율을 대상으로 심리적 장벽수준이 존재하는가를 검증하고, 심리적 장벽수준이 각 통화옵션의 내재변동성에 유의한 영항을 주는가를 조사하였다. 각 환율당 내재변동성 데이터가 제공되는 약 10년간의 일별환율을 기준으로 심리적장벽의 존재와 위치를 파악하였고, 조건부 수익률의 평균과 변동성, 그리고 각 환율을 기초자산으로 하는 통화옵션의 내재변동성에 GARCH(1,1)모형을 사용하여 심리적 장벽을 돌파하는 시점을 기준으로 전, 후에 유의한 모멘텀 효과가 있음을 확인하였다. 특히 내재변동성 데이터에서 그 현상이 더욱 뚜렷하였으며, 이는 심리적 장벽이 통화옵션의 가격에 영향을 준 직접적 증거로 해석된다. In this paper, we examine the existence of the psychological barriers in three foreign exchange rate, won/dollar, euro/dollar, yen/dollar, and test that the psychological barriers effect to the implied volatilities of the FX options. For each exchange rate, the existence and spots of the psychological barriers are estimated from roughly 10 years data for each currency rate, and GARCH (1,1) model was applied to observe the momentum effect about the mean and variance of the conditional returns, and the implied volatility of the FX-options for each currency rate near the psychological barriers. Since this effect is more clearly observed on the implied volatility data, this fact supports that psychological barriers affects to the price of the FX-options.

무인항공기 자동착륙을 위한 활강궤적 추종 알고리듬 성능분석

최영현,구훤준,김종성,석진영,Choi, Young-Hyun,Koo, Hueon-Joon,Kim, Jong-Sung,Suk, Jin-Young 제어로봇시스템학회 2005 제어·로봇·시스템학회 논문지 Vol.11 No.3

Automatic landing of UAVs receives increasing interest these days, with increasing number of the developed UAV systems. In this paper, a glidepath tracking algorithm of the subscale UAV was proposed and the performance was analyzed. Flight data analysis shows that the existing autolanding flight control algorithm has a classical type glidepath control. This paper presents an alternative glidepath tracking strategy based on embedded flight control law. The performance of the proposed strategy was investigated through the TDP(Touch Down Point) error analysis with regard to various flight environment: steady headwind, atmospheric disturbance, communication transfer delay. It was verified that the proposed glidepath tracking strategy can be successfully applied to the practical autolanding of UAV systems.

Characterization of PM2.5 and gaseous emissions during combustion of ultra-clean biomass via dual-stage treatment

Lee, Young-Joo,Park, Ju-Hyoung,Song, Gyu-Seob,Namkung, Hueon,Park, Se-Joon,Kim, Joeng-Geun,Choi, Young-Chan,Jeon, Chung-Hwan,Choi, Jong Won Elsevier 2018 Atmospheric environment Vol.193 No.-

<P>Biomass combustion technology is widely considered as an attractive option to remove carbon dioxide emissions and thus could become a viable option for next generation co-combustion power plants with coal. Among biomasses, the faster growing herbaceous biomass (Miscanthus) is relatively inexpensive as a solid fuel but has higher mineral contents (especially high levels of alkali metals) than that of a lignocellulosic biomass (Pitch pine) which leads to ultrafine particle emissions during combustion. This study proposes a dual stage treatment method to extract the inherent minerals in a herbaceous biomass prior to the combustion test. The method consists of an initial treatment with a basic (NaOH) solution and a sequential treatment with an acidic (CH3COOH) solution. To verify the proposed method, we investigated the variations in both the mineral contents and the PM, NOx and SO2 emissions between raw- and treated samples. The experimental results show that sodium, potassium and chloride in the treated herbaceous sample, which are the major minerals that generate ultrafine particles, were removed up to 96.3, 99.4 and 98.3%, respectively. The proposed method is more effective for herbaceous biomasses due to its higher Brunauer Emmett Teller (BET) value. Furthermore, the treated herbaceous biomass is even environmentally superior to raw lignocellulosic biomasses currently used in co-combustion power plants with coal in terms of the PM2.5, NOx and SO2 emissions, for which their rejection was measured as 60, 25 and 46%, respectively. These results will help to reduce the energy and costs for De-NOx (selective catalytic reduction, SCR system) and De-SO2 (scrubber) units.</P>

퍼지로직을 이용한 무인항공기의 충돌 회피

장대수(Dae-Su Jang),조신제(Shin-Je Cho),탁민제(Min-Jea Tahk),구훤준(Hueon-Joon Koo),김종성(Jong-Soeng Kim) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.7

본 논문에서는 국제민간항공기구와 미연방항공청에서 규정한 “Right of way” 규정과 조종사의 경험을 바탕으로 한 퍼지로직을 이용한 무인항공기의 충돌회피를 다루고 있다. 이 규정을 적용하기 위해 퍼지로직을 이용한 충돌회피 시스템을 설계하였다. 그리고 충돌회피 시스템이 작동할 조건을 위해 결심로직을 설계하였다. 결심로직은 상대방위, CPA까지의 시간, CPA에서의 거리 등 세가자의 중요 요소로 구성되어 있다. 결심로직의 적용은 NMAC를 회피하기위해 설계 되어졌으며 몇 가지 시뮬레이션을 통하여 검증하였다. 결론 적으로 본 논문에서는 일반공역에서 유인항공기와 함께 비행할 수 있도록 무인항공기의 “See and Avoid” 능력을 수행할 수 있는 방법을 제안하였다. This thesis describes collision avoidance using fuzzy logic based on “Right of way” rules of ICAO and FAA and pilot’s experiences for Unmanned Aerial Vehicle(UAV). To apply the rules, we designed fuzzy logic based collision avoidance system. And we also designed decision logic for enable condition of collision avoidance system. Decision logic have three kinds of core key, i.e. Relative Range, Time of CPA (Closest Point of Approach) and Distance at CPA. Application of decision logic made a possible to avoid NMAC(Near Mid-Air Collision) and it has been verified through several simulations. To conclude, we proposed the method to carry out “See and Avoid” ability on UAVs, which is capability to mingle with manned aircraft in civil airspace.

비식량자원 기반 혼합 바이오액(impurity sugar)이 함침된 하이브리드석탄의 제조 및 그 연료 특성에 관한 연구

박주형(Ju-Hyoung Park),송규섭(Gyu-Seob Song),이영주(Young-Joo Lee),박세준(Se-Joon Park),남궁훤(Hueon Namkung),이동욱(Dong-Wook Lee),최종원(Jong Won Choi),김정근(Joeng-Geun Kim),송광호(Kwang Ho Song),최영찬(Young-Chan Choi) 대한설비공학회 2017 대한설비공학회 학술발표대회논문집 Vol.2017 No.11

TCAS-Ⅱ를 응용한 무인항공기의 충돌회피기동 연구

조신제(Shin-Je Cho),장대수(Dae-Su Jang),탁민제(Min-Jae Tahk),구훤준(Hueon-Joon Koo),김종성(Jong-Soeng Kim) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.4

본 논문에서는 항공기충돌방지장치인 TCAS-Ⅱ를 응용한 무인항공기의 충돌회피를 다룬다. TCAS-Ⅱ의 최소운용성능표준 문서에 기초한 시뮬레이션 프로그램을 구현하고, TCAS-Ⅱ가 제공하는 다양한 수직회피 명령을 자동조종장치의 입력으로 변환하여 최대고도변화율이 상이한 두 가지 무인항공기의 충돌회피 성능을 비교분석한다. 낮은 최대고도 변화율을 가진 무인항공기에 TCAS-Ⅱ를 적용할 때 발생 가능한 Near Mid-Air Collision을 방지할 수 있는 방안으로서, 최대고도변화율과 고도를 고려한 개선된 알고리듬을 제안하였다. 이 알고리듬은 ADS-B 개념에 의한 보다 넓은 감시범위가 제공된다는 전제하에 사용될 수 있다. In this paper, the collision avoidance of Unmanned Aerial Vehicles(UAVs) by applying the Traffic alert and Collision Avoidance System Ⅱ(TCAS-Ⅱ) is introduced. The performances of two UAVs whose maximum vertical rates are different each other are compared and analysed by not only converting many TCAS-Ⅱ commands into an autopilot input but also implementing a computer program based on the Minimum Operational Performance Standards for TCAS-Ⅱ. As the alternative to a possible Near Mid-Air Collision for UAVs whose maximum vertical rates are low, we have proposed a modified algorithm considering the maximum vertical rate and altitude. The modified algorithm is available on the assumption that a wider surveillance range is provided by a ADS-B system.