화력발전소의 온배수를 열원으로 이용하는 시설원예 난방용 히트펌프 시스템의 열교환기 설계기준 설정

유영선(Young Sun Ryou),강연구(Youn Ku Kang),장재경(Jae Kyung Jang),김영화(Young Hwa Kim),김종구(Jong Goo Kim),강금춘(Geum Chun Kang) (사)한국생물환경조절학회 2012 생물환경조절학회지 Vol.21 No.4

본 연구에서는 화력발전소에서 온배수의 형태로 배출되는 폐열을 히트펌프의 열원으로 이용하여 온실의 난방에 활용할 수 있는 히트펌프 시스템을 설계 제작하였으며, 난방 성능을 분석하여 PE 파이프 열교환기의 설계기준을 제시하고자 하였다. PE 파이프 열교환기의 내경은 20㎜, 두께는 2㎜였으며, Roll의 직경은 1,000㎜로 하였다. 연구결과 PE파이프 열교환기의 적정 길이는 1.0RT당 75m로 설계하는 것이 바람직할 것으로 판단되었으며, 이때 히트펌프시스템의 난방성능계수(COPh)는 3.8로 나타났다. This study was carried out in order to determine the optimum length of a roll type PE pipe heat exchanger employed in the water-to-water heat pump system using the waste heat of the heated effluent flowed out from thermal power generation plants as a heat source. And the heat pump system of 30 RT for an experimental test was designed and manufactured. And also PE pipes were employed to recover the waste heat from the heated effluent. The inside diameter of PE pipe heat exchanger was 20 ㎜, the thickness was 2 ㎜ and the diameter of a roll was 1,000 ㎜. And from the results of this study, we found that the optimum length of PE pipe heat exchanger was 75 m per the heat pump capacity of 1.0 RT (3.51 ㎾) and then the heating COP of heat pump system was 3.8.

미생물연료전지의 가축분뇨 처리 가능성 연구

김영화 ( Young Hwa Kim ),유영선 ( Young Sun Ryou ),최정은 ( Jung Eun Choi ),김세희 ( Se Hee Kim ),장재경 ( Jae Kyung Jang ),김종구,이성현 ( Sung Hyoun Lee ),강연구 ( Young Goo Kang ) 한국미생물생명공학회(구 한국산업미생물학회) 2010 한국미생물·생명공학회지 Vol.38 No.4

본 연구는 미생물연료전지를 이용하여 액비를 처리하고 동시에 유용한 전기에너지 발생이 가능한지를 실험한 것이다. 탄소섬유전극(graphite felt)와 스테인레스 스틸망을 다른 비율로 충진한 single-chamber 미생물연료전지를 이용하였으며 탄소섬유전극보다 스테인레스망을 더 많이 충진한 미생물연료전지를 대조구(CMFC)로 하여 탄소섬유전극이 더많이 충진된 미생물연료전지(SMFC)와 서로 비교하였다. 농화 배양이 끝난 후, SMFC로부터 발생되는 전류는 3.167±80mg/L의 액비를 공급할 때 18 mA가 안정적으로 발생되었다. 이때 최대 전력밀도와 전류밀도는 각각 680 mW/m3와 3,770 mA/m3이었으며, CMFC의 전력밀도와 전류밀도보다는 높았다. 화학적산소요구량(COD)는 SMFC와 CMFC에서 3,718±80 mg/L에서 865±21과 930±14 mg/L로 감소하여 각각72.7%와 70.6%가 감소되었다. SMFC와 CMFC로부터 부유물질(SS)은 99% 이상이 감소되는 것을 확인하였다. 또한SMFC의 암모니아성질소, 질산성질소, 그리고 인산염인과 같은 영향물질 농도의 변화도 각각 65.4%, 57.5%, 그리고 73.7%이 감소되었으며 CMFC의 경우도 거의 유사한 제거율을 보였다. 이들 결과로부터 저가 재료가 충진한 미생물 연료전지를 이용함으로써 경제적 효과를 기대할 수 있음은 물론 가축분뇨로부터 적지만 전기 에너지가 발생하는 것을 확인할 수 있었다. In this study the feasibility of simultaneous electricity generation and treatment of swine farm wastewater using microbial fuel cells (MFCs) was examined. Two single-chamber MFCs containing an anode filled with different ratio of graphite felt and stainless-steel cross strip was used in all tests. The proportion of stainless-steel cross strip to graphite felt in the anode of control microbial fuel cell (CMFC) was higher than that of swine microbial fuel cell (SMFC) to reduce construction costs. SMFCs produced a stable current of 18 mA by swine wastewater with chemical oxygen demand (COD) of 3,167±80 mg/L after enriched. The maximum power density and current density of SMFCs were 680 mW/m3 and 3,770 mA/m3, respectively. In the CMFC, power density and current density was lower than that of SMFC. CODs decreased by the SMFC and CMFC from 3,167±80 to 865±21 and 930±14 mg/L, achieving 72.7% and 70.6% COD removal, respectively. The suspended solid (SS) of both fuel cells was also reduced over 99% (4,533±67 to 24.0±6.0 mg/L). The concentration of nutritive salts, NH4 +, NO3 -, and PO4 3-, dropped by 65.4%, 57.5%, and 73.7% by the SMFC, respectively. These results were similar with those of CMFC. These results show that the microbial fuel cells using electrode with mix stainless-steel cross strip and graphite felt can treat the swine wastewater simultaneously with an electricity generation from swine wastewater.

제3발표장 : 생물생산시설 및 환경공학 분야 ; 농촌형 녹색마을 내 재생에너지 투입 효과분석

김종구 ( Jong Goo Kim ),유영선 ( Young Sun Ryou ),강연구 ( Youn Koo Kang ),김영화 ( Young Hwa Kim ),장재경 ( Jae Kyung Jang ) 한국농업기계학회 2013 한국농업기계학회 학술발표논문집 Vol.18 No.1

식품 및 환경, 기타 Single-cathode와 Dual-cathode 미생물연료전지의 탄소원과 질산성질소의 전류발생 특성

장재경 ( Jae Kyung Jang ),이은영 ( Eun Young Lee ),유영선 ( Young Sun Ryou ),이성현 ( Sung Hyoun Lee ),황지환 ( Ji Hwan Hwang ),이형모 ( Hyung Mo Lee ),김종구 ( Jong Goo Kim ),강연구 ( Youn Koo Kang ),김영화 ( Young Hwa Kim ) 한국미생물생명공학회 2011 한국미생물·생명공학회지 Vol.39 No.4

Microbial fuel cells (MFC), devices that use bacteria as a catalyst to generate electricity, can utilize a variety of organic wastes as electron donors. The current generated may differ depending on the organic matter concentrations used, when other conditions, such as oxidant supply, proton transfer, internal resistance and so on, are not limiting factors. In these studies, a single-cathode type MFC (SCMFC) and dual-cathode type MFC (DCMFC) were used to ascertain the current`s improvement through an increase in the contact area between the anode and the cathode compartments, because the cathode reaction is one of the most serious limiting factors in an MFC. Also an MFC was conducted to explore whether an improvement in electricity generation resulted from oxidizing the carbon sources and nitrates. About 250 mg L-1 sodium acetate was fed to an anode compartment with a flow rate of 0.326 mL min-1 by continuous mode. The current generated from the DCMFC was higher than the value produced from MFC with a single cathode. COD removal of dual-cathode MFC was also higher than that of single-cathode MFC. The nitrate didn`t affect current generation at 2 mM, but when 4 and 8 mM nitrate was supplied, the current in the single-cathode and dual-cathode MFC was decreased by 98% from 5.97±0.13 to 0.23±0.03 mA and 8.40±0.23 to 0.20±0.01 mA, respectively. These results demonstrate that increasing of contact area of the anode and cathode can raise current generation by an improvement in the cathode reaction.

가축분뇨내 질소이온 제어가 전류발생에 미치는 영향

장재경(Jae Kyung Jang),유영선(Young Sun Ryou),박정수(Jung Soo Park),임영순(Youngsoon lim),장인섭(In Seop Chang),김종구(Jong Goo Kim),강연구(Youn Koo Kang),김영화(Young Hwa Kim) 한국신재생에너지학회 2013 한국신재생에너지학회 학술대회논문집 Vol.2013 No.11

Single-cathode와 Dual-cathode로 구성된 미생물연료전지에서 전류발생 향상을 위한 전자수용체로서의 Nitrate와 Ferric ion의 이용

장재경 ( Jae Kyung Jang ),유영선 ( Young Sun Ryou ),김종구 ( Jong Goo Kim ),강연구 ( Youn Koo Kang ),이은영 ( Eun Young Lee ) 한국미생물생명공학회(구 한국산업미생물학회) 2012 한국미생물·생명공학회지 Vol.40 No.4

미생물연료전지 운전을 할 때, 전압손실을 감소시키기 위한 다양한 방법들이 시도 되고 있다. 이 연구는 전해질과 저가의 금속이온을 전자수용체로 이용하여 전류발생을 확인하였다. 전해질로 phosphate buffer를 사용한 경우, 공기만 사용하였을 때보다 향상되었으며, 공기의 공급이 없이는 효과가 적은 것으로 나타났다. 전자수용체로 질산염(nitrate)을 사용하였을 때 산소를 공급하지 않았을 때보다 높은 전류발생을 보였으나 공기포화 물을 사용한 경우와 비교하여 전류발생이 향상되지는 않았다. 질산염을 양극부에 적용시에는 음극부와 양극부 모두 폐수처리가 가능한 시스템으로 구성하여 운전한다면 전류발생은 낮으나 서로 다른 폐수를 처리 할수 있을 것으로 판단된다. 이 연구에서 적용한 3가지 방법중에서 3가 철이온을 사용하였을 때 전류 발생이 가장 높았으며, 공기를 공급하지 않아도 전류 발생이 높게 유지되는 것으로 나타났다. 이것은 미생물연료전지의 규모를 증대시킬 때 폭기가 필요 없는 시스템을 구축할 수 있어 큰 장점으로 작용할 것으로 판단된다. 따라서 3가 철이온은 지구상에 가장 많은 금속 이온 중 하나로 용해도가 낮으나 저가의 3가 철이온을 잘 이용한다면 양극부 반응속도를 효율적으로 향상 시킬 수 있을 것으로 판단된다. The quantity of research on microbial fuel cells has been rapidly increasing. Microbial fuel cells are unique in their ability to utilize microorganisms and to generate electricity from sewage, pig excrement, and other wastewaters which include organic matter. This system can directly produce electrical energy without an inefficient energy conversion step. However, with MFCs maximum power production is limited by several factors such as activation losses, ohmic losses, and mass transfer losses in cathodes. Therefore, electron acceptors such as nitrate and ferric ion in the cathodes were utilized to improve the cathode reaction rate because the cathode reaction is very important for electricity production. When 100 mM nitrate as an electron acceptor was fed into cathodes, the current in single- cathode and dual-cathode MFCs was noted as 3.24±0.06 mA and 4.41±0.08 mA, respectively. These values were similar to when air-saturated water was fed into the cathodes. One hundred mM nitrate as an electron acceptor in the cathode compartments did not affect an increase in current generation. However, when ferric ion was used as an electron acceptor the current increased by 6.90±0.36 mA and 6.67±0.33 mA, in the singlecathode and dual-cathode microbial fuel cells, respectively. These values, in single-cathode and dual-cathode microbial fuel cells, represent an increase of 67.1% and 17.6%, respectively. Furthermore, when supplied with ferric ion without air, the current was higher than that of only air-saturated water. In this study, we attempted to reveal an inexpensive and readily available electron acceptor which can replace platinum in cathodes to improve current generation by increasing the cathode reaction rate.

Effect of ammonium on the current generation in the microbial fuel cell

장재경(Jang, Jae Kyung),최정은(Choi, Jung Eun),유영선(Ryou, Young Sun),이성현(Lee, Sung Hyung),김종구(Kim, Jong Goo),강연구(Kang, Youn Koo),김영화(Kim, Young Hwa),이형모(Lee, Hyung Mo) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05

These studies carried out to know the effect of ammonium on the current generation in the microbial fuel cells (MFCs). MFCs used in the study were enriched with anaerobic digestion sludge and operated for 3 years using artificial wastewater (AWW). When the current was stably generated, ammonium ion with 27.0{pm}0.0, 51.5{pm}0.0, 103.5{pm}0.0mg/L with acetate fed into the anode compartment. The current values under condition included ammonium were changed from its initial 6.30{pm}0.06 to 6.28{pm}0.36, 5.95{pm}0.61, 5.64{pm}0.38mA, respectively. The current value was slightly decreased to 5.64{pm}0.38mA compared to 6.30{pm}0.06mA generated from MFC without ammonium ion in the AWW. But After 3days operating under ammonium concentration with 103.5{pm}0.0mg/L, the current was unstably generated when artificial wastewater without ammonium was fed again. MFC enriched with AWW without ammonium ion was inhibited by high concentration of ammonium. At this time, the ammonium was removed 5.27~16.41 mg per day under all conditions.

가축분뇨를 이용한 미생물연료전지의 농화배양 단계에서 미생물 군집 변화

장재경(Jae Kyung Jang),홍선화(Sun Hwa Hong),유영선(Youg Sun Ryou),이은영(Eun Young Lee),장인섭(In Seop Chang),강연구(Youn Koo Kang),김종구(Jong Goo Kim) 大韓環境工學會 2013 대한환경공학회지 Vol.35 No.12

이 연구는 전기화학적 활성을 갖는 미생물들을 알아내기 위하여 농화배양 단계에서 시간에 따라 미생물연료전지의 미생물 군집 변화를 알아본 것이다. 접종원으로 하수처리장 혐기 소화액와 가축분뇨를 1 : 1로 혼합한 액을 사용하였다. 농화 배양 과정에서 미생물 생장곡선에 따라 지체기, 대수성장기 그리고 정지기로 전류발생 패턴을 보면서 구분하였다. 전류가 안 정적으로 발생되는 시점을 농화배양이 끝난 시점으로 판단하였으며, 이때 전류는 0.84 ± 0.06 mA가 발생되었다. 농화배양이 되어 가는 과정에서 미생물군집 변화를 전기영동(DGGE)에서 확인하여 시간에 따라 새롭게 나타나는 band나 농도가 높아지는 band 17개를 잘라내어 염기서열을 분석하였다. 이 결과 지체기와 대수성장 단계에서는 Clostridium, Rhodocyclaceae, Bacteriodete 그리고 Uncultured bacterium 등이 검출되었고, 정지기에서는 Geobacter sp., Rhodocyclaceae, Candidatus, Nitrospira, Flavobactriaceae, 그리고 Uncultured bacterium 등이 검출되었다. Geobactor의 경우는 이미 전기활성 미생물로 알려져 있는 미생물 종으로 이를 포함하여 이 연구에서 검출된 다른 미생물들 중에도 전기활성이 있는 미생물을 포함하고 있을 것으로 판단된다. These studies were attempted to investigate the change of microbial community of anode of microbial fuel cell using swine wastewater in the enrichment step with the lapse of time. Microbial fuel cells enriched by a 1 : 1 mixture of anaerobic digestive juices of the sewage treatment plant and livestock wastewater. Enrichment culture step was divided into three stages to indentify the microorganisms. It was separated by each lag phase, exponential phase, and stationary phase. These steps were determined by the change of the current value. The current after enrichment was generated about 0.84 ± 0.06 mA. We were cut out the different 17 bands in the DGGE fingerprint gel to do sequencing. The bands which the concentration was increasing or newly appearing with the lapse of time were included for this study. In the lag and exponential phase, Clostridium, Rhodocyclaceae, Bacteriodetes, and Uncultured bacterium etc. were detected. There were in the stationary phase Geobacter sp., Rhodocyclaceae, Candidatus, Nitrospira, Flavobactriaceae and uncultured bacterium etc. Geobactor among microorganisms detected in this study is known as the Electrochemically active microorganisms. It may include electrochemically active microorganisms to be considered as electrical activity microorganisms.