• 한국응용과학기술학회지
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• 제32권1호
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• pp.48-55
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• 2015

전 세계적으로 증가하고 있는 선박 배출가스 규제를 위해 국제해사기구(IMO)는 배출되고 있는 가스의 부정적 환경영향에 대한 부각과 함께 법적인 규제를 강화하고 있다. 국제해사기구(IMO) 규제에 따라, 발트 해 연안을 지나는 모든 배들은 배출가스 제거창치를 장착해야 한다. 다양한 최신 탈황/탈질 장치가 소개되고 있는 가운데, 선박의 제한 된 공간을 활용한 폐 세정액 회수 공정 또한 중요한 기술로 발전 가능하다. 탈황/탈질 장치 후단에서 발생되는 폐 세정액은 질산암모늄, 황산암모늄과 같은 유용부산물을 포함하고 있다. 본 연구는 선택적 유기용매 염석 법, 저온 결정화 추출, 열 감압농축을 이용하여 유용부산물로서 질산암모늄을 추출하였다. 열 감압농축으로 얻어진 부산물을 반복적 유기용매 추출방법으로 정제했을 시 가장 높은 순도의 질산암모늄이 추출 되었다. 분석 장비를 통해 추출 된 유용 부산물의 성분 및 특성을 평가하였다.

• Korean Chemical Engineering Research
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• 제47권3호
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• pp.386-393
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• 2009

본 연구는 도심녹지의 대기질 영향을 정량적으로 해석하기 위해 수행되었다. 도심의 '근린공원 녹지'가 가스상 오염물질인 '질소산화물'과 '황산화물'에 미치는 영향을 분석하였으며, 이를 위해 녹지의 대기환경영향평가 모델링시스템이 개발되었다. 모델링은 서울 도심의 대표적 근린공원이라 할 수 있는 종로구의 파고다 공원 인근지역을 대상으로 수행되었다. 모델링 결과, 도시 근린공원의 수목은 자체적으로 오염물질을 흡수 제거하여 대기질을 개선시키는 기능이 크다고는 볼 수 없지만, 상대적으로 친환경적인 토지이용형태(배출원이 거의 없고, 해당지역 및 주변지역에서 원활한 기류소통 촉진)를 유지함으로서 대기환경 악화를 억제하는 효과는 탁월한 것으로 나타났다. 대기오염이 심한 도시지역에서의 대기정책은 오염원 추가건설 제어를 위한 녹지보호정책을 우선적으로 고려해야 할 것으로 판단된다.

• 한국분무공학회지
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• 제19권3호
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• pp.115-122
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• 2014

As a demand for an automobile increases, air pollution and a problem of the energy resources come to the fore in the world. Consequently, governments of every country established ordinances for green-house gas reduction and improvement of air pollution problem. Especially, as international oil price increases, engine using clean energy are being developed competitively with alternative transportation energy sources development policy as the center. Bio ethanol, one of the renewable energy produced from biomass, gained spotlight for transportation energy sources. Studies are in progress to improve fuel supply methods and combustion methods which are key features, one of the engine technologies. DI(Direct Injection), which can reduce fuel consumption rate by injecting fuel directly into the cylinder, is being studied for Green-house gas reduction and fuel economy enhancement at SI(Spark Ignition). GDI(Galoine Direct Injection) has an advantage to meet the regulations for fuel efficiency and $CO_2$ emissions. However it produces increased number of ultrafine particles, that yet received attention in the existing port-injection system, and NOX. As fuel is injected into the cylinder with high-pressure, a proper injection strategy is required by characteristics of a fuel. Especially, when alcohol type fuel is considered. In this study, we tried to get a base data bio-ethanol mixture in GDI, and combustion for optimization. We set fuel mixture rate and fuel injection pressure as parameters and took a picture with a high speed camera after gasoline-ethanol mixture fuel was injected into a constant volume combustion chamber. We figured out spraying characteristic according to parameters. Also, we determine combustion characteristics by measuring emissions and analyzing combustion.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권2호
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• pp.45-51
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• 2006

In this paper, we propose a new architecture of Information Granulation based genetically optimized Self-Organizing Fuzzy Polynomial Neural Networks (IG_gSOFPNN) that is based on a genetically optimized multilayer perceptron with fuzzy polynomial neurons (FPNs) and discuss its comprehensive design methodology involving mechanisms of genetic optimization, especially information granulation and genetic algorithms. The proposed IG_gSOFPNN gives rise to a structurally optimized structure and comes with a substantial level of flexibility in comparison to the one we encounter in conventional SOFPNNs. The design procedure applied in the construction of each layer of a SOFPNN deals with its structural optimization involving the selection of preferred nodes (or FPNs) with specific local characteristics (such as the number of input variables, the order of the polynomial of the consequent part of fuzzy rules, and a collection of the specific subset of input variables) and addresses specific aspects of parametric optimization. In addition, the fuzzy rules used in the networks exploit the notion of information granules defined over system's variables and formed through the process of information granulation. That is, we determine the initial location (apexes) of membership functions and initial values of polynomial function being used in the premised and consequence part of the fuzzy rules respectively. This granulation is realized with the aid of the hard c-menas clustering method (HCM). To evaluate the performance of the IG_gSOFPNN, the model is experimented with using two time series data(gas furnace process and NOx process data).

• 한국추진공학회지
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• 제12권5호
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• pp.43-50
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• 2008

서인천 복합 화력발전소의 GE 7FA+e DLN-2.6 가스터빈 연소기 튜닝을 실시하였다. DLN-2.6 연소기는 기동초기 저출력 조건에서 yellow plume 현상과 정상상태보다 높은 수준의 연소진동이 발생하는 문제점이 있었다. 본 논문의 목적은 기동초기의 yellow plume과 연소진동의 발생 원인을 규명하여 실 연소기를 안정적으로 운용할 수 있는 최적의 운전 조건을 제시하는 것이다. 실연소기 튜닝과정을 통해 얻은 자료를 분석한 결과 기동초기 모드 3($20{\sim}30MW$)에서 PM 1 노즐에서의 과농한 혼합기(${\phi}{\sim}1$)에 의해 yellow plume이 생성되었다. 모드 6B($40{\sim}45MW$)에서의 연소진동 발생은 $120{\sim}140Hz$ 부근에서 생성되었고 연소기 온도에 영향을 받지 않는 cold flow 특성으로 보이며 PM 3 노즐에서의 유량과 관련이 있었다.

• 대한환경공학회지
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• 제35권12호
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• pp.967-972
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• 2013

질소산화물 저감에 큰 효과가 있는 MILD 연소는 고온의 배기가스가 연소로내에 유입되는 양에 따라 질소산화물 저감 특성이 많은 영향을 받는다. 본 연구에서는 동심원관 형태의 MILD 연소로에서 바깥 원통의 배기가스 통로에서부터 안쪽 원통의 연소통로 사이에 연결관을 설치하고 배기가스를 유입하기 위해 coanda 노즐을 사용하였다. 이러한 coanda 노즐의 기하학적 형상 변화에 따라 고압공기 유량, 배기가스 유입량 특성을 수치해석을 통해 살펴봄으로써 최적의 coanda 노즐 형상을 도출하는 것을 본 연구의 목적으로 하였다. 본 연구의 전산 해석의 결과는 conada 노즐의 노즐 통로 간격이 0.5 mm, 노즐 각도 $4^{\circ}$, 노즐 확관 길이 146 mm일 때 최적의 유입량비가 되었고 노즐 통로 수직 길이는 유입량비에 무관하였다.

• 한국자동차공학회논문집
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• 제22권2호
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• pp.156-165
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• 2014

This paper is the first investigation on the effect of flow control methods on the part load performance in a spark ignition engine. For comparison of the methods, two control devices, port throttling and masking, were applied to a conventional engine without any design change of the intake port. Steady flow evaluation shows that steady flow rates per unit opening area and swirl ratio are very low compared with the port throttling and saturated from mid-stage valve lift, however, swirl increases slightly as the lift is higher in case of 1/4 masking control. In the part load performance, the effect of simple port throttling on lean misfire limit expansion is limited and insufficient; on the other hand a masking improves the limit considerably without any port modification for increasing swirl. Also the results show that the intake flow control improves the combustion with following two mechanisms: stratification induced by the combination of the flow pattern and the fuel injection timing attribute to ignition ability and the intensified flow ensure fast burn. In addition fuel consumption reduces under the flow controls and the reduction rate is different according to the operation conditions and control methods. At the Stoichiometric and/or low speed and low load the throttling method is more advantageous; however vice versa at lean and high load condition. Finally, the throttling is more efficient for HC reduction than masking, on the other side the NOx emissions increase under the masking and decrease under the port throttling compared with conventional port scheme.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.102-112
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• 2012

The vast stores of biomass available in the worldwide have the potential to displace significant amounts of fuels that are currently derived from petroleum sources. Fast pyrolysis of biomass is one of possible paths by which we can convert biomass to higher value products. The wood pyrolysis oil (WPO), also known as the bio crude oil (BCO), have been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of BCO in a diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the BCO. One of the easiest way to adopt BCO to diesel engine without modifications is emulsification of BCO with diesel and bio diesel. In this study, a diesel engine operated with diesel, bio diesel (BD), BCO/diesel, BCO/bio diesel emulsions was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine fuelled by BCO emulsions were examined. Results showed that stable engine operation was possible with emulsions and engine output power was comparable to diesel and bio diesel operation. However, in case of BCO/diesel emulsion operation, THC & CO emissions were increased due to the increased ignition delay and poor spray atomization and NOx & Soot were decreased due to the water and oxygen in the fuel. Long term validation of adopting BCO in diesel engine is still needed because the oil is acid, with consequent problems of corrosion and clogging especially in the injection system.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.81-89
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• 2014

This study researched on the effect of HP/LP-EGR system to improve fuel consumption of Low Temperature Combustion Engine. Firstly, low temperature combustion engine with HP/LP-EGR system was established using 6.0L wastegate turbocharger HDDI engine. And suppliable EGR rate of the engine was proven to be enough to realize stable low temperature combustion. Then, optimum operating strategy was founded to develop fuel consumption of the engine. Control parameters were HP/LP-EGR valve and IPCV(Intake Pressure Control Valve) duty. Experiments method was that characteristics of the engine were measured and analyzed according to HP/LP-EGR strategies while EGR rate was fixed. Operating range for the strategy were divided into three parts, low load for low temperature combustion, high load for conventional diesel combustion, and transient condition. Finally, with the above strategy of this study, BSFC of the engine was improved about 2% compared to the base engine, and emission level, NOx and PM, met Tier4Final emission regulation.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.80-86
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• 2008

Recently, controlled auto ignition(CAI) in gasoline engines are drawing more attentions due to its extremely low level of NOx emissions and potentials in lowering the fuel consumption rate. The one of the key techniques for realizing CAI combustion in engines is the control of valve system. Since the valve linkage system with higher complexity, or even earn-less valve systems, such as electro-hydraulic and electro-magnetic system, are adopted in CAI engines, it is not easy to estimate the valve lift profile from earn profiles. Therefore new measurement techniques for valve lift in CAI engines have been tried and tested. In this paper, hole type valve lift sensor was developed and tested to check the applicability in CAI engines. The valve lifts could be obtained from the sensor signal, which depends on the distance from the sensor to magnet attached to valve. Various engine speeds, ranging from 2,000 to 6,000 rpm, and valve lifts, maximum up to 9.7 mm, were tested. It was found that the sensor output for valve lift had accuracy of 98% in comparison with the basic specifications of valve lift through improvements of sensor driving circuit.