• 한국환경과학회지
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• 제23권11호
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• pp.1881-1888
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• 2014

Greenhouse gas (GHG) emissions from dye wastewater treatment processes were estimated by analysing their mass and energy balances, which were then used as baseline information for environmental assessment. The total GHG emissions from dye wastewater treatment plants were divided into direct emissions from the treatment processes and indirect ones from electricity usage. The amounts of $CO_2$, $CH_4$ and $N_2O$ emissions were calculated according to the Intergovernmental Panel on Clime Change (IPCC) guideline for the GHG target management system. For 3 years between 2011 and 2013, direct and indirect emissions were on average 8,742.7 and 7,892.0 Ton.$CO_2eq/year$, respectively, with the former exhibiting 52.6 %. Also, compared to 2012, in 2013, the eco-efficiency indicator by the GHG emissions was found to be more than 1, suggesting that environmental quality was effectively improved.

• 한국분무공학회지
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• 제20권3호
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• pp.156-161
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• 2015

This paper described the effect of dual clutch transmissions on the stability emissions characteristic in a GDI engine at vehicle Inspection and Maintenance(I/M) program. In order to investigate the influence of direct injection gasoline engine with DCT, the experimental apparatus consisted of GDI engine with 4 cylinder, dynamometer and exhaust emissions analyzer. Analyzed emission gas include CO, HC and NOx results that DCT vehicle in the case of NOx, HC in automatic transmission vehicles less than 1/2 level was confirmed to be exhausted. However vehicle specific power increases CO also has increased.

• 한국대기환경학회지
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• 제30권2호
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• pp.150-160
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• 2014

Greenhouse gas (GHG) and Air Pollution (AP) emission inventories have been constructed and estimated independently up-to-date in Seoul. It causes difficulty in GHG and AP integrated management due to a difference in emission inventories. In this study, we constructed GHG and AP integrated emission inventories for direct and indirect sources in Seoul during the year 2010 in Energy activities for estimating GHG and AP emissions were derived from IPCC guideline, guidelines for local government greenhouse inventories, air pollutants calculation manual, and Indirect Emission Factors (IEF) reported by Korea Power Exchange. The annual GHG emission was estimated as 50,530,566 $tonCO_{2eq}$, of which 54.8% resulted from direct sources and the remaining 45.2% from indirect sources. Among direct sources, transportation sector emitted the largest GHG, accounting for 47.3% of the total emission from direct sources. As with indirect sources, purchased electricity sector only emitted 98.6% of the total emission from indirect sources. The annual AP emission was estimated as 283,701 tonAP, of which 85.9% was contributed by the combined AP emissions of transportation and fugitive sectors. Estimation of individual air pollutant showed that the largest source were transportation sector for CO, $NO_x$, TSP, $PM_{10}$ and NH3, non-energy sector for $SO_x$, and fugitive sector for VOCs. This study found some limitations in estimating GHG and AP integrated emissions, such as nonconforming emission inventories between GHG and AP, and no indirect AP emission factor of purchased electricity, and so on. Those should be further studied and improved for more effective GHG and AP integrated management.

• 한국자동차공학회논문집
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• 제20권4호
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• pp.39-45
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• 2012

Today gasoline engines for vehicular application are not only faced with stringent emission regulation but also with increasing requirements to better fuel economy, while guaranteeing power density. The spray-guided type gasoline direct injection (GDI) engine has an advantage of improved thermal efficiency and lower harmful emissions. Centrally mounted high pressure injector and adjacent spark plug allow stable lean combustion due to the flexible mixture stratification. In the present study, the performance and emissions characteristics of developed spray-guided type GDI combustion system were evaluated at various excess air ratio conditions. The specific fuel consumption and nitrogen oxides ($NO_x$) emissions were reduced due to the achievement of stable lean combustion under flammability limit. Multiple injection strategy was not helpful to improve fuel consumption while further reduction of $NO_x$ emissions was possible.

• 한국환경과학회지
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• 제20권11호
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• pp.1465-1481
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• 2011

The accuracy of ozone sensitivity coefficients estimated with HDDM (High-order Decoupled Direct Method) can vary depending on the $NO_x$ (Nitrogen Oxides) and VOC (Volatile Organic Compound) conditions. In order to evaluate the applicability of HDDM over the Seoul Metropolitan Area (SMA) during a high ozone episode in 2007 June, we compare BFM (Brute Force Method) and HDDM in terms of the $1^{st}$-order ozone sensitivity coefficient to explain ozone change in response to changes in NOx and VOC emissions, and the $2^{nd}$-order ozone sensitivity coefficient to represent nonlinear response of ozone to the emission changes. BFM and HDDM estimate comparable ozone sensitivity coefficients, exhibiting similar spatial and temporal variations over the SMAduring the episode. NME (Normalized Mean Error) between BFM and HDDM for the episode average $1^{st}$- and $2^{nd}$-order ozone sensitivity coefficients to NOx and VOC emissions are less than 3% and 9%, respectively. For the daily comparison, NME for the $1^{st}$- and $2^{nd}$-order ozone sensitivity coefficients are less than 4% ($R^2$ > 0.96) and 15% ($R^2$ > 0.90), respectively. Under the emission conditions used in this study, two methods show negative episode average $1^{st}$-order ozone sensitivity coefficient to $NO_x$ emissions over the core SMA. The $2^{nd}$-order ozone sensitivity coefficient to $NO_x$ emissions leads ozone to respond muchnonlinear to the reduction in $NO_x$ emissions over Seoul. Nonlinear ozone response to reduction in VOC emissions is mitigated due to the $2^{nd}$-order ozone sensitivity coefficient which is much smaller than the $1^{st}$-order ozone sensitivity coefficient to the emissions in the magnitude.

• Journal of Advanced Marine Engineering and Technology
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• 제31권7호
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• pp.823-832
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• 2007

This paper presents the static characteristics of EGR-WI combined system. The water injection system was statically characterized by recording the engine exhaust outlet $NO_x$ emissions for comparison with baseline $NO_x$ emissions. Effects of the water injection system on CO and HC emissions and fuel consumption were examined. The research engine used for these experiments was a 103 kW turbocharged, intercooled, 2.5 L VM Motori CIDI engine equipped with a cooled EGR system. Water injection in the intake system demonstrated the potential for significant reductions in engine outlet $NO_x$ emissions. The system has reduced engine outlet $NO_x$ emissions by 40-50%, but caused significant increases in CO and HC emissions, particularly at low loads. Fuel consumption effects were minimal.

• 한국기후변화학회지
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• 제9권3호
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• pp.273-281
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• 2018

The purpose of this study is to consider the effectiveness of continuous $CO_2$ emission monitoring in waste incinerator. To prevent global warming, many countries are trying to reduce $CO_2$, the main greenhouse gas. Currently, Korea is implementing an emission trading scheme to reduce $CO_2$, and waste incinerators are included in this scheme as major $CO_2$ sources. However, when using waste incinerators, $CO_2$ is discharged during incineration of various types of wastes, therefore it is very difficult to calculate the amount of emissions according to IPCC guidelines. In addition, the estimation of $CO_2$ emissions by calculation is known to lack of accuracy comparing with actual emissions. Currently, Korea is operating CleanSYS, which enables continuous measurement of gases emitted into the atmosphere. Therefore, it is possible to estimate the $CO_2$ emissions of waste incineration facilities. The IPCC, which published $CO_2$ emission calculation guidelines, recognizes that direct measurement of emission is a more advanced method in cases of various $CO_2$ emission sources such as a waste incineration facility. Also, Korean emission trading scheme guidelines allow estimation of $CO_2$ emissions by continuous measurement at waste incineration facilities. Therefore, this study considers the effectiveness of a direct measurement method by comparing the results of CleanSYS with the calculation method suggested by the IPCC guidelines.

• 대한환경공학회지
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• 제33권12호
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• pp.874-885
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• 2011

현재 국가 온실가스 배출량 산정은 IPCC 가이드라인을 이용하여 화석연료 사용량을 우리나라의 에너지 분야의 온실가스 배출량 산정에 있어서 전력사용은 간접배출, 기타연료 사용은 직접배출로만 산정하고 있어, 자치단체의 온실가스 감축전략을 수립하기에는 미흡한 점이 있다. 본 연구는 16 개 광역자치단체의 2007년 에너지 사용량을 기초로 에너지 부문(석탄, 석유 제품, 전력, 도시가스)에 의한 온실가스물질의 직접 및 간접 배출량을 산정하였다. 각 지방자치단체의 에너지 분야 온실가스 배출량은 에너지 연료 생산단계에서 발생되는 간접배출량(Indirect Emissions)과 에너지 연료를 사용 했을 때 발생되는 직접배출량(Direct Emissions)으로 나누어 산정하였다. 각 지방자치단체별 직간접 발생량을 합산할 경우, 2007년 국내 에너지 부문 총 온실가스 배출량은 497,083 천톤 $CO_2eq.$이였으며, 간접 온실가스 배출부분에서 전체 발생량의 48%인 240,388 천톤 $CO_2eq.$, 직접 온실가스 배출부분에서 52%인 256,694 천톤 $CO_2eq.$의 온실가스가 배출되는 것으로 나타났다. 이 수치는 현재 기존의 평가방법으로 산정되어진 온실가스 배출량 439,698 천톤 $CO_2eq.$와 약 13%의 차이를 보이고 있다. 따라서 기후변화에 대응하기 위한 자치단체 및 국가 온실가스 감축 전략수립을 위해서는 우리 실정에 맞는 배출계수의 개발과 직, 간접배출을 고려한 체계적인 온실가스 배출량 산정방법의 정립이 필요한 것으로 나타났다.

• 한국연소학회지
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• 제18권1호
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• pp.7-12
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• 2013

A quasidimensional program is developed for a four stroke cycle homogeneous GDI (Gasoline Direct Injection) engine. It includes models for spray, burning rate and chemistry to predict knock and emissions. With early injection a homogeneous GDI engine goes through spark ignited, turbulent premixed combustion as in PFI (Port Fuel Injection) engines. The cylinder charge is divided into unburned and burned zone with the latter divided into multiple zones of equal mass to resolve temperature stratification. Validation is performed against measured pressure traces, NOx and CO emissions at different load and RPM conditions. Comparison is made between an empirical knock model and predictions by the chemistry model in this work.

• Journal of Mechanical Science and Technology
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• 제18권5호
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• pp.865-876
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• 2004

A new concept of reduced quasi-dimensional combustion model for a direct injection diesel engine is developed based on the previously developed quasi-dimensional multi-zone model to improve the computational efficiency. In the reduced model, spray penetration and air entrainment are calculated for a number of zones within the spray while three zones with aggregated spray zone concept are used for the calculation of spray combustion and emission formation processes. It is also assumed that liquid phase fuel appears only near the nozzle exit during the breakup period and that spray vaporization is immediate in order to reduce the computational time. Validation of the reduced model with experimental data demonstrated that the new model can predict engine performance and NO and soot emissions reasonably well compared to the original model. With the new concept of reduced model, computational efficiency is significantly improved as much as 200 times compared to the original model.