• 한국해양공학회지
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• 제35권6호
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• pp.393-402
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• 2021

As greenhouse gas emissions from maritime transport are increasing, the International Maritime Organization is continuously working to strengthen emission regulations. Liquefied natural gas (LNG) fuel is less advantageous as a point of CO₂ reduction due to the methane leakage that occurs during the bunkering and operation of marine engines. In this study, greenhouse gas emissions from an LNG-fueled ship were analyzed from the perspective of the life cycle. The amount ofmethane emission during the bunkering and operation procedures with various boil-off gas (BOG) treatment methods and gas engine specifications was analyzed by dynamic simulation. The results were also compared with those of other liquid fuel engines. As a result, small LNG-fueled ships without a BOG treatment facility emitted 32% more greenhouse gas than ships utilizing marine gas oil or heavy fuel oil. To achieve a greenhouse gas reduction via a BOG treatment method, a gas combustion unit or re-liquefaction system must be mounted, which results in a greenhouse gas reduction effect of about 25% and 30%. As a result of comparing the amount of greenhouse gas generated according to the BOG treatment method used with each tank size from the perspective of the operating cycle with the amounts from using existing marine fuels, the BOG treatment method showed superior effects of greenhouse gas reduction.

• Journal of Advanced Marine Engineering and Technology
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• 제37권7호
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• pp.792-798
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• 2013

In this study, we have carried out measurement for exhaust emissions such as particulate matter (PM), nitrogen oxide and carbon oxide from main engines installed on the training ships, HANBADA and HANNARA, of Korea Maritime University. In particular, we considered the two conditions; at arrivals/departures and at constant speed of about 160 rpm. The result showed that the concentration of PM at the ship arrival was 2.41mg/m3. On the other hand, when the ship is on the navigation condition, the concentration of PM was 1.34 mg/m3. The concentrations of nitrogen oxide and carbon oxide were measured in the range of 1,120~1,600 ppm and 320~1,450 ppm at the arrival and departure at the port. Under constant speed condition, the concentrations of nitrogen oxide and carbon oxide were 913~1,470 ppm and 73~460 ppm, respectively. Generally, the concentrations of exhaust emissions under the arrivals and departures were higher than that of constant speed condition. These results imply that the ship operation skill to prevent a sudden load change of main engine is needed during the arrival or departure. In addition, it means that the difference of exhaust emissions according to navigation conditions has to be considered when the reduction technologies of air pollutants from ships are developed.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.155-165
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• 2013

The effect of gaseous ammonia direct injection on the engine performance and exhaust emissions in gasoline-ammonia dual fueled spark-ignition engine was investigated in this study. Results show that based on the gasoline contribution engine power increases as the ammonia injection timing and duration is advanced and increased, respectively. However, as the initial amount of gasoline is increased the maximum power output contribution from ammonia is reduced. For gasoline-ammonia, the appropriate injection timing is found to range from 320 BTDC at low loads to 370 BTDC at high loads and the peak pressures are slightly lower than that for gasoline due to the slow flame speed of ammonia, resulting in the reduction of combustion efficiency. The brake specific energy consumption (BSEC) for gasoline-ammonia has little difference compared to the BSEC for gasoline only. Ammonia direct injection causes slight reduction of $CO_2$ and CO for all presented loads but significantly increases HC due to the low combustion efficiency of ammonia. Also, ammonia direct injection results in both increased ammonia and NOx in the exhaust due to formation of fuel NOx and ammonia slip.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.49-54
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• 2003

The purpose of this work is to investigate the effect of premixed fuel on the reduction of exhaust emissions in premixed charge compression ignition engine. The premixed fuel is injected into the intake manifold to form homogeneous pre-mixture in the combustion chamber. The pre-mixture is ignited by a small amount of diesel fuel directly injected into the cylinder. In the case of gasoline as a premixed fuel of the engine, $NO_x$ and smoke concentration of exhaust emissions were reduced compared with the conventional diesel engine. But in the event of diesel fuel for premixed fuel, the rate of smoke reduction was small compared with the case of gasoline as a premixed fuel. HC and CO emissions were increased at high premixed ratio in the case of two premixed fuels. The combustion characteristics of the engine such as the combustion pressure, the rate of heat release, and other characteristics are compared.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.128-135
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• 2008

EGR(exhaust gas recirculation) is considered as a most effective method to reduce the NOx emissions. But high EGR tolerance is always pursued not only for its advantages of the pumping loss reduction and fuel economy benefit in Gasoline-Hybrid engine. However, the occurrence of excessive cyclic variation with high EGR normally prevents substantial fuel economy improvements from being achieved in practice. Therefore, the optimum EGR rate should be carefully determined in order to achieve low fuel consumption and low exhaust emission. In this study, 2 liters gasoline engine with E-EGR system was used to investigate the effects of EGR on fuel efficiency, combustion stability, engine performance and exhaust emissions. With optimal EGR rates, the fuel consumption was improved by 4%. This improvement was achieved while a reduction in NOx emissions of 75% was accomplished. Increase of EGR gas temperature causes the charge air temperature to affect the knock phenomenon and moreover, the EGR valve lift changes for the same control signal.

• Environmental Engineering Research
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• 제22권3호
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• pp.294-301
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• 2017

This paper is based on experiments conducted on a stationary, four stroke, naturally aspirated air cooled, single cylinder compression ignition engine coupled with an electrical swinging field dynamometer. Instead of 100% diesel, 20% Jatropha oil methyl ester with 80% diesel blend was injected directly in engine beside 25% pre-mixed charge of diesel in mixing chamber and with 20% exhaust gas recirculation. The performance and emission characteristics are compared with conventional 100% diesel injection in main chamber. The blend with diesel premixed charge with and without exhaust gas recirculation yields in reduction of oxides of nitrogen and particulate matter. Adverse effects are reduction of brake thermal efficiency, increase of unburnt hydrocarbons (UBHC), carbon monoxide (CO) and specific energy consumption. UBHC and CO emissions are higher with Diesel Premixed Combustion Ignition (DPMCI) mode compared to compression ignition direct injection (CIDI) mode. Percentage increases in UBHC and CO emissions are 27% and 23.86%, respectively compared to CIDI mode. Oxides of nitrogen ($NO_x$) and soot emissions are lower and the percentage decrease with DPMCI mode are 32% and 33.73%, respectively compared to CIDI mode.

• 동력기계공학회지
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• 제15권6호
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• pp.11-15
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• 2011

This study investigated the symptoms of the a reduction in output while driving on the road, or increasing of fumer out exhaust gas on inclined road while working air-conditioner in summer. Notice how the experiment in 2010, the Ministry of Environment(Chapter No. 2010-46), and how the vehicle emissions inspection was carried out. 2500cc Diesel cars used in the study were used and compare to output of engine, exhaust gas, inhalation temperature measurement Inhalation of cold air has not been supplied to all agencies when comparing the results when cold air intake temperature of the supply air-conditioning switch range control from 1 to 4, the temperature drops $98^{\circ}C$ to $78^{\circ}C$. At the momentum of switch level 4, output from 63ps to 66ps after the connection has increased 9.6 percent, the highest concentration of exhaust emissions were reduced by 42.8%. This research can contribute in part to the reduction of exhaust directly supply into the cooling air intake line, doing the output of diesel cars in the summer. In addition, construction equipment and machinery that are currently being used excluding the engine's intercooler cooling of the supply line via a separate output in the summer and help reduce exhaust emissions is expected.

• Coupled systems mechanics
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• 제1권3호
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• pp.285-295
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• 2012

In this paper, two types of porous burners with radial and axial flow have been modeled numerically and compared. For this purpose, governing equations were solved one-dimensionally for methane-air premix gas. The mechanism used in simulating combustion phenomenon was 15 stage reduced mechanism based on GRI3.0. In order to compare the two burners, the inlet flow rate and fuel-air ratio have been assumed equal for the two burners. The results of the study indicated that reduction in speed and increase in cross-section area in the direction of flow have a considerable influence on the behavior of radial burner in comparison to axial burner. Regarding temperature distribution inside the burner, it was observed that the two above mentioned factors can be influential in temperature of flame propagation region. Also, regarding distribution of CO and NO emission, the results indicate that the porous radial burner has lower emissions in comparison to the axial once. The output radiative heat transfer efficiency of the two burners was also compared and in this case also even the radial porous burner was found to be preferable.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.549-563
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• 2022

Continuous global warming is causing ecosystem destruction and direct damage to human life. The main cause of global warming is greenhouse gases, which account for more than 90 % of carbon dioxide. The leaders of each country signed the Paris Agreement at the United Nations Convention on Climate Change (UNFCCC) to reduce greenhouse gas emissions. Currently, the total amount of CO₂ emitted from South Korea is 664.7 million tons as of 2018, ranking eighth in the world. 37 % of South Korea's total CO₂ emissions come from the construction & building field, especially the cement production, which is a construction material. Carbon reduction technologies can be largely divided into four types: carbon reduction (CC), carbon reduction and storage technology (CCS), carbon reduction and utilization technology (CCU), and carbon reduction, storage and utilization technology (CCUS). Overseas, CCUS technology is mainly applied to reduce and store CO₂ emitted from construction and construction field. A technology for permanently storing CO₂ through mineralization by capturing CO₂ and utilizing CO₂ into a cement production process was developed, and this technology is applied to the entire cement industry. However, the development of CCUS technology applicable to the cement industry is still insignificant in South Korea. In this study, carbon dioxide reduction technology and methods for reducing carbon dioxide emitted during the cement manufacturing process, which is the main component of concrete mainly used in civil engineering construction, were investigated. Overseas, it has reached the commercialization stage beyond the demonstration stage as a way to reduce carbon dioxide by vomiting carbonation reactions. Accordingly, if carbon dioxide reduction plan technology generated during cement manufacturing is developed based on domestic technology differentiated from foreign technology, it is expected to contribute one more step to the carbon neutrality policy.

• 한국건설관리학회논문집
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• 제18권1호
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• pp.74-82
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• 2017

2011년부터 온실가스 에너지 목표관리제와 같은 국가적 온실가스 감축 규제가 대학에도 적용되기 시작하면서 2000년대 급속한 증가를 보이는 것으로 알려졌던 대학의 온실가스 배출량은 2011년 이후 안정세 및 하락세를 보여 오고 있다. 따라서, 온실가스 배출 규제의 시행을 계기로 대학사회가 온실가스 에너지에 대한 관리를 강화하고 있고 그 효과가 나타나고 있다고 이야기할 수 있게 되었다. 특히, 보다 강력한 제도적 속성을 지닌 배출권거래제 시행 준비 시기에는 총량이 줄어드는 결과를 보이는 등 온실가스 다배출 대학을 중심으로 감소하는 추세로 전환되었다고 평가할 수 있다. 본 연구에서는 개별 대학의 온실가스 감축 활동을 세부적으로 추적하지는 않았지만 온실가스 배출에 영향을 끼치는 주요 활동도 자료를 분석하였고, 그 결과 대학의 온실가스 배출이 2011년 이전에는 연구수혜액, 그리고 2013년 이후에는 연면적의 변화가 영향을 주는 것을 확인하였다. 이에, 향후 대학의 온실가스 감축 목표 설정 원단위는 연면적을 기준으로 하는 것이 바람직하다고 판단되며, 보다 체계적인 대학의 온실가스 감축을 지원하기 위한 면적 단위 온실가스 배출량의 기준 수립과 관련 정보 공유가 필요하다고 할 수 있다.