• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.521-527
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• 2005

The effects of an urae injection at the exhaust pipe for a 4-cylinder DI(Direct Injection) diesel engine are investigated experimentally. The urea quantity was controlled by NOx quantity and MAF(Manifold Air Flow). The urea injection must be precisely metered and then I used the urea syringe pump. I have tested 4 kinds of items that were with the EGR base engine and without the EGR engine. Then I tested each urea-SCR(Selective Catalytic Reduction) system. As the results, I can caculate the SUF(Stoichiometric Urea Flow) and visualize the NOx results by variation of engine speed and engine load. Also, I can make the NOx map. Therfore, I knew that NOx reduction effects of the urea-SCR system without the EGR engine were better than the with EGR base engine except of low load and low speed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.2
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• pp.244-251
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• 2001

This paper describes a design study of heat exchanger assembly to be used for low NOx condensing gas boiler. In this study, specifications of each heat exchanger components(upper and lower fin-type HEX, coil-type HEX, baffle) were investigated experimently by using model apparatus and analytical model, and comprehensive performances of the pilot gas boiler were examined. As a result, the boiler efficiency for heating and hot-water reached 90% and 94%, respectively. NOx and CO emission are less than 50ppm and 200ppm (0$_2$0% basis), respectively, which are very improved results than those of conventional bunsen-type boiler. But it is considered that supplementary investigations necessary for CO emission improvement and optimum design with boiler capacity.

• Journal of Mechanical Science and Technology
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• v.16 no.7
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• pp.950-958
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• 2002

The combustion characteristics of a low NOx burner using reburning technology have been experimentally studied. The return burner usually has three distinct reaction zones which include the primary combustion zone, the reburn zone and the burnout zone by provided secondary air. NOx is mainly produced in a primary combustion zone and a certain portion of NOx can be converted to nitrogen in the rebury zone. In the burnout zone, the unburned mixtures are completely oxidated by supplying secondary air. Liquefied Petroleum Gas (LPG) was used as main and reburn fuels. The experimental parameters investigated involve the main/reburn fuel ratio, the primary/secondary air ratio, and the injection location of rebury fuel and secondary air. When the amount of return fuel reaches to the 20-30% of the total fuel used, the overall NO reduction of 50% is achieved. The secondary air is injected by two different ways including vertical and parallel injection. The injector of secondary air is located at the downstream region of furnace for a vertical-injection mode, which is also placed at the inlet primary-air injection region for a parallel-injection mode. In case of the vertical injection of the secondary air flow, the NOx formation of stoichiometric condition at a primary combustion zone is nearly independent of the rebury conditions (locations, fuel/air ratios) while the NOx emission of the fuel-lean condition is considerably influenced by the reburn conditions. In case of the parallel injection of the secondary air, the NOx emission is sensitive to the air ratio rather than the fuel ratio and the reburning process often coupled with the multiple air-staging and fuel-staging combustion processes.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.174-179
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• 2004

Domestic marine diesel engine makers reduce the NOx emission mostly by applying low NOx fuel nozzle and injection timing retard. However, it is necessary to develop high efficient technology (EGR, DWI and SCR, etc.) to reduce NOx emission in order to prepare for the further reinforcement of the NOx emission limit. Also, in the near future, IMO will restrict additively THC, PM and CO with NOx. Therefore, domestic engine makers have to prepare for it and the relevant government ministries should give a sufficient support to these technology research and establish or amend the relevant law, which should include the excursion riverboat.

• 연구논문집
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• s.27
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• pp.101-108
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• 1997

The characteristics of combustion and emissions in multi-staged oil burner have been experimentally studied for the various range of equivalence ratios, drop sizes and fuel formulations. Malvern system was used to measure droplet size of fuel. Light fuel oil and light fuel oil doped with pyridine($C_5H _5N$) were used to investigate the effects on fuel NOx emission. The emissions of NO and CO in exhaust gas and the flame temperatures were measured by the gas analyzer and thennocouples. NOx emissions were increased by increasing the excess air ratio (range:$lambda=1.1-1.4$) or decreasing the SMD of droplet in single-staged burner. In comparison with the single-staged burner, the emission of NOx in multi-staged burner was reduced by 50% but CO emission was slightly increased. It is found that multi-staged burner has a good capability in reducing thermal NOx resulting from the distributed heat release rate and lower flame temperature in fuel-rich and fuel-lean combustion zone. Moreover, the fuel NOx emission of the multi-staged burner is lower than that of single-staged burner, because multi-staged burner has fuel rich zone where fuel N is converted to $N_2$ more than NO. In 3-staged burner, the percentage of each stage combustion air have strong influence on emission characteristics. It is also found that NOx emission can be reduced by decreasing inner and outer air percentage or increasing middle air flow rate and CO emission is vice versa.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.318-321
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• 2005

The design and performance test of a low NOx gas turbine combustor to be used in 55kW class micro-gasturbine engine was performed in KARI's combustion test facility. The combustor is reverse flow-can type for easy installation of injector and other parts and LNG is used as fuel. The performance targets are $99.5\%$ combustion efficiency, less 10ppm NOx, $30\%$ patten factor and $4\%$ pressure loss. Most of the performances required are satisfied.

• Journal of the Korean Society of Combustion
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• v.12 no.4
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• pp.22-30
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• 2007

The NOx emission characteristics were studied in an oscillating combustion burner equipped with a specially designed proportioning valve. The effects of various parameters on the NOx emission which are important in oscillating combustion were investigated. Also, the effects of coincident application of flue gas recirculation(FGR) were evaluated. The results show that oscillating combustion is an efficient tool for reducing NOx in the burner. Up to 53% of NOx reduction could be acquired in low frequency and small duty ratio conditions. The coincident application of FGR further reduced the NOx emission up to 74%. Thus, this study assured that oscillating combustion technology with FGR could be a fascinating method for NOx reduction in industrial burners.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.628-636
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• 2005

In this paper. the effects of a WI(Water Injection) in the intake pipe for a 4-cylinder Dl(Direct Injection) diesel engine are investigated experimentally, The WI system was controlled by the duty cycle from the intake manifold's temperature and MAF(Manifold Air Flow) First. effect of EGR on NOx reduction was investigated. Then WI system was applied to reduce NOx As the results. we can make the NOx map and visualize the NOx results by variation of engine speed and engine load It was known that effect of WI system on NOx reduction without the EGR was better than the with EGR base engine except of low load and speed condition.

• Journal of the Korean Society of Combustion
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• v.4 no.1
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• pp.131-139
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• 1999

A Numerical Analysis of NOx production in Hydrogen-Air flame is performed using the quasi-laminar reaction modelling. As results, in low global strain rate region, $U_F/D_F\;{\leq}\;50,000$, the quasi-laminar reaction modelling reproduces the experimentally observed EINOx half power scaling that the ratio of EINOx and flame residence time, $L_f^3(D_F^2U_F)$, is proportional to the square root of global strain rate. Thus, it suggests that turbulence-chemistry interaction has a minor impact on the trend of NOx production in low global strain rate region. However, the quasi-laminar reaction modelling predicts the higher temperature and NOx than experimentally observed. This overprediction may be due to the lack of radiation and quasi-laminar reaction modelling.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.455-464
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• 1998

Removal teals of Soxmox were performed using low density ceramic filters doped with various catalysts. Disc type (50 mmO.Dx10 mmt) low density ceramic filters were doped with three different catalysts such as Cu to remove SOx and NOx, and Mn and Co to remove NOx. The air permeabilities and specific surface areas were 40~50cc/min.cm2.cmH2O and 4.1~8.88 m2/g, respectively. Also, the peak pore sizes of catalyst support were 3~5nm. Tests were focused to search optimum operating temperatures for different catalysts. It was found that as the CuO content increases, SOx removal efficiency was increased. NOx removal efficiencies for Mn, Cu and Co, were 85% at 30$0^{\circ}C$, 90% at 40$0^{\circ}C$ and 90% at 45$0^{\circ}C$, respectively.