http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Hydrothermal carbonization of lipid extracted algae for solid fuel production
( Donghwan Sohn ),( Jongkeun Lee ),( Junhee Ryu ),( Youngho Park ),( Sungwan Cho ),( Ki Young Park ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 한국폐기물자원순환학회 심포지움 Vol.2019 No.1
As the microalgae are used as the third generation biomass, the area of cultivation is narrow and the growth is fast, so much research is being conducted for the production of biodiesel. During biodiesel production, lipid extracted algae (LEA) is generated from the algal biodiesel production industries. The LEA residue, after the extraction of lipid, is commonly considered as waste. The objective of this study is to produce alternative solid fuels from LEAs via HTC process as a method of bio-carbon recovery and waste disposal. In this study, feedstocks were used LEA form Chlorella vulgaris were extracted by Dimethyl Ether (DME), and untreated C. vulgaris. Experiments were performed using a lab-scale reactor with a volume of 1 L, into which 300mL of LEA or C.vulgaris feedstock, mixed with an equal amount of distilled was water loaded. The anaerobic condition was achieved by purging the reactor with nitrogen gas for sufficient time before the HTC experiments. The operating temperature ranged between 180 to 270℃ with the reaction being maintained for 30 min in the presence of subcritical water. The contents of the reactor were mixed vigorously using an agitator, rotating at 200 rpm. After the HTC treatment, the residual steam was discharged from the reactor. The reaction time, as a result, the carbon contents of LEA and microalgae increased from 47.16% to 58.45% and from 50.91% to 59.36%, respectively, as the treatment temperature increased until 210℃. Also, the calorific value was also increased, indicating the highest value of 6,594 kcal/kg and 6,800 kcal/kg at 210℃. LEA has low carbon content and calorific value compare with C.vulgaris, but it has enough high carbon content and calorific value for using solid fuel. In addition, the characteristics of solid fuel of LEA are enhanced by HTC, and the product may be sufficient to use solid fuel.
수열탄화를 통한 하수슬러지의 고형연료화 및 연료특성 개선 평가
손동환 ( Donghwan Sohn ),이종근 ( Jongkeun Lee ),박기영 ( Ki Young Park ) 한국폐기물자원순환학회(구 한국폐기물학회) 2017 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2017 No.-
급속한 경제 성장과 함께 국내 하수처리 시설의 수는 증가하여 왔으며, 이로 인해 하수처리 시설로부터 발생되는 하수슬러지의 양도 꾸준히 증가하여 왔다. 2014년 기준 연간 발생량이 3,651,029 톤에 이르는 하수슬러지는 국제협약과 국내 법제도로 인해 해양투기와 직매립이 금지됨에 따라 이를 처리하기 위한 적절한 방법의 개발이 요구된다. 최근 하수슬러지 처리 방법을 살펴보면 전체 재활용되는 양의 43.8% (w/w)인 상당량의 하수슬러지가 건조 및 탄화의 방법을 통해 연료화 되고 있다. 하지만 슬러지의 경우 높은 함수율로 인해 건조 및 탄화 공정에 많은 양의 에너지가 소모되는 문제점이 있다. 이를 극복하기 위한 수단으로 슬러지에 함유되어 있는 수분을 열분해 반응에 이용할 수 있으며 비교적 낮은 온도에서 바이오매스의 탄화가 가능한 수열탄화가 많은 관심을 받고 있다. 본 연구에서는 슬러지의 수열탄화를 실시하고 생성된 바이오차를 이용하여 고형연료로서의 특성을 분석하는 한편 연료특성 개선을 위한 타 바이오매스와의 혼합처리 가능성을 확인하였다. 연구결과 180-270 ℃의 온도조건에서 생성된 바이오차는 모두 국내 바이오고형연료제품의 기준 발열량인 3,000 kcal/kg 보다 높은 4,000 kcal/kg 이상의 발열량을 보였다. 하지만 바이오고형연료제품 기준 중 회분함량에 대한 항목을 살펴보면 원시료 기준 29.11% (w/w)로 관련 기준인 15% (w/w)와 비교할 때 높았던 슬러지내 회분함량이 수열탄화 과정을 거치며 처리 온도에 따라 32.75-47.64% (w/w)로 오히려 증가하는 것을 확인할 수 있었다. 따라서 슬러지를 고형연료로 사용하기 위해서는 회분함량 개선을 위한 혼합물의 투입이 필요할 것으로 판단되었다. 이를 위하여 최근 대량 생산이 용이하여 차세대 에너지원으로 주목받고 있는 미세조류와의 혼합을 통한 연료특성 개선 가능성을 확인하였다. 미세조류의 경우 슬러지와 동일한 조건에서 수열탄화를 통하여 처리될 경우 회분함량이 1.29-2.96% (w/w)로 현저히 낮고, 발열량 또한 6,740 kcal/kg으로 높은 값을 보였다. 따라서 적절한 비율로 혼합된 슬러지와 미세조류의 수열탄화를 통한 처리 시 생성된 바이오차는 국내 바이오고형연료제품 기준을 만족할 수 있을 것으로 판단된다.
Fault Diagnosis Method based on Feature Residual Values for Industrial Rotor Machines
Kim, Donghwan,Kim, Younhwan,Jung, Joon-Ha,Sohn, Seokman Korea Electric Power Corporation 2018 KEPCO Journal on electric power and energy Vol.4 No.2
Downtime and malfunction of industrial rotor machines represents a crucial cost burden and productivity loss. Fault diagnosis of this equipment has recently been carried out to detect their fault(s) and cause(s) by using fault classification methods. However, these methods are of limited use in detecting rotor faults because of their hypersensitivity to unexpected and different equipment conditions individually. These limitations tend to affect the accuracy of fault classification since fault-related features calculated from vibration signal are moved to other regions or changed. To improve the limited diagnosis accuracy of existing methods, we propose a new approach for fault diagnosis of rotor machines based on the model generated by supervised learning. Our work is based on feature residual values from vibration signals as fault indices. Our diagnostic model is a robust and flexible process that, once learned from historical data only one time, allows it to apply to different target systems without optimization of algorithms. The performance of the proposed method was evaluated by comparing its results with conventional methods for fault diagnosis of rotor machines. The experimental results show that the proposed method can be used to achieve better fault diagnosis, even when applied to systems with different normal-state signals, scales, and structures, without tuning or the use of a complementary algorithm. The effectiveness of the method was assessed by simulation using various rotor machine models.
진동신호 특성 예측 및 분류를 통한 회전체 고장진단 방법
김동환(Donghwan Kim),손석만(Seokman Sohn),김연환(Yeonwhan Kim),배용채(Yongchae Bae) 한국소음진동공학회 2014 한국소음진동공학회 학술대회논문집 Vol.2014 No.10
In this paper, we have developed a new fault detection method based on vibration signal for rotor machinery. Generally, many methods related to detection of rotor fault exist and more advanced methods are continuously developing past several years. However, there are some problems with existing methods. Oftentimes, the accuracy of fault detection is affected by vibration signal change due to change of operating environment since the diagnostic model for rotor machinery is built by the data obtained from the system. To settle a this problems, we build a rotor diagnostic model by using feature residual based on vibration signal. To prove the algorithm’s performance, a comparison between proposed method and the most used method on the rotor machinery was conducted. The experimental results demonstrate that the new approach can enhance and keeps the accuracy of fault detection exactly although the algorithm was applied to various systems.
Hyrothermal carbonization of sewage sludge for energy recovery
( Gabin Kim ),( Donghwan Sohn ),( Jongkeun Lee ),( Seunghyun Lee ),( Kyung Jin Min ),( Ki Young Park ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 한국폐기물자원순환학회 심포지움 Vol.2019 No.1
One way to recover energy from sewage sludge is to use it as fuel through drying and carbonization. Although this method accounts for 43.8% (w/w)of sludge recycling rate, however, it consumes much energy in the fueling process due to the high water content of sewage sludge. In order to overcome this problem, a hydrothermal carbonization method which can carbonize sewage sludge at a lower temperature by using water in sewage sludge is being used as a new treatment method. In this study, to increase the efficiency of the sewage sludge fueling method for the energy independence of the sewage treatment plant, the primary sludge generated in the sewage treatment plant and the digested sludge are converted into fuel through hydrothermal carbonization, and the solid fuel characteristics of the product are analyzed Sludge selection and optimum treatment conditions for solid fuel production. In this study, sludge generated in J wastewater treatment plant in Seoul was used. Experimental conditions were as follows: 300 mL of feedstock and the same amount of distilled water was added to the reactor and heated to 180~270℃. The reaction time was the same for 30 minutes and aimed at the optimum temperature was obtained. Both the primary sludge and the digested sludge showed an increase in carbon content, a decrease in oxygen and hydrogen content, and an improvement in coal quality as the water temperature increased. However, as the treatment temperature increased, the calorific value of the primary sludge improved, but the calorific value of the digested sludge decreased. This phenomenon is considered to be the result of increased ash content in the carbonization process. In order to use sewage sludge generated from sewage treatment facilities as solid fuel, primary sludge with high heating value is more suitable than digestion sludge and 210℃ with high energy recovery efficiency is suitable because the treatment temperature is the highest.
Lee, Jongkeun,Lee, Kwanyong,Sohn, Donghwan,Kim, Young Mo,Park, Ki Young Elsevier 2018 ENERGY Vol.153 No.-
<P><B>Abstract</B></P> <P>In this study, hydrothermal carbonization was conducted to convert lipid extracted algae (<I>Chlorella vulgaris</I>) from the algal biodiesel process to produce hydrochar, while evaluating its feasibility for use as a solid fuel. Hydrothermal carbonization was conducted at a relatively low temperature range, owing to the energy consumption during the process. Based on the results, the properties of lipid extracted algae as a solid fuel improved during hydrothermal carbonization, being comparable to the low-ranked coals. The hydrochars thus produced showed stable combustion characteristics at high temperature. Moreover, the sulfur and ash content in the lipid extracted algae decreased through devolatilization during hydrothermal carbonization, allowing the hydrochar (low sulfur and ash content) to be considered as a clean energy source. Thus, a sustainable integration process, combining the hydrochar production from lipid extracted algae with the algal biodiesel process, seems to be feasible for solid fuel production and disposal of waste.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The hydrothermal carbonization of lipid extracted algae was conducted. </LI> <LI> Hydrochar had appropriate characteristics for using as alternative solid fuel. </LI> <LI> Hydrochar showed stable combustion characteristics at high temperature. </LI> <LI> Hydrochar to be considered as clean energy source due to low sulfur and ash content. </LI> <LI> A green integration process, hydrochar production using LEA, seems to be feasible. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>