• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.50-57
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• 2014

The performance of five kind adsorbents, which can reduce nitrogen oxide (NOx) from the diesel engine occupying 85% of the fishing boat, was carried out and the emission reduction filter was manufactured and evaluated in the adsorption efficiency of the emission gas for 240 KW diesel portable generator. As a NOx emission filter made of mordenite which has an excellent cation exchange capacity was manufactured by ball type adsorbents having excellent specific surface area. The adsorption efficiency of mordenite material applying the emission reduction filter began to show up at the operating time 10 minutes in comparison with the activated carbon and zeolite materials, and it was exposed to continue until 100% capability with passing by 20 minutes. So the adsorption efficiency of the NOx reduction filter consistently maintained at the averaged 80%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.7
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• pp.1039-1046
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• 2002

Co-flow axisymmetric laminar premixed flame of methane was used to study the influence of air temperature and $N_2$ addition on the flame structure, temperature field and emission characteristics. OH 2-D images and temperatures along the centerline were measured experimentally by PLIF and CARS techniques respectively to observe the influences of dilution and thermal effects of $N_2$ in the gas mixture. Also, the concentration of NOx was measured at each condition by gas analyser to see the suppression effect of N2 addition on NOx emissions. It was found that OH concentrations distribute widely as air temperature goes higher, while the effect of $N_2$ addition is not significant. But $N_2$ addition highly contributes to the flame front and NOx emissions which was argued to be due to the reduction of flame temperature. In accordance with experimental study, numerical simulation using CHEMKlN code was carried out to compare the temperature results with those acquired by CARS measurement, and we could find that there is good agreement between those results.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.356-361
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• 2003

The objective of this study is a qualitative comparison between line-integrated OH chemiluminescence ($OH{\ast}$) image and its Abel inversion image at different phase of the oscillating pressure field. PIV(Particle Image Velocimetry) measurements were conducted under non-reacting conditions to see the global flow structure. Also NOx emission was measured to investigate the effect of fuel-air premixing on combustion instability and emission characteristics. Experiments were carried out in an atmospheric pressure, laboratory-scale dump combustor operating on natural gas. Combustion instabilities in present study exhibited a longitudinal mode with a dominant frequency of ${\sim}341.8$ Hz, which corresponded to a quarter wave mode of combustor. Heat release and pressure waves were in-phase when instability occurred. Results gave an insight about the location where the strong coherence of pressure and heat release existed. Also an additional information on active control to suppress the combustion instabilities was obtained. For lean premixed combustion, strong correlation between $OH{\ast}$ and NOx emissions was expected largely due to the exponential dependence of thermal NOx mechanism on flame temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.12
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• pp.811-820
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• 2007

A Study on the optimal design of the AIG(Ammonia Injection Grid) to improve the performance of DeNOx facilities in the HRSG(Heat Recovery Steam Generator) was performed using the CFD analysis. On the basis of the flow analysis results in the case that the AIG in the HRSG was not installed, the numerical analyses according to the positions of AIG, injection angles of nozzle and the control of ammonia injection quantity were carried out. The standard deviation according to factors was calculated for quantitative comparison. As the results, the AIG in the HRSG should be installed in the position that the uniform flow field shows through the exact flow analysis in the previous of the AIG design and installation. In the case the AIG has already been installed and non uniform flow distribution shows, it is recommended that flow correction device or KoNOx catalyst should be used. Otherwise, the control of ammonia injection angle or the ammonia injection quantity using the velocity profile analysis is demanded to accomplish the optimal performance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.201-207
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• 2012

This study was carried out to improve the design of heat exchanger for small marine diesel engine. As air pollutants emitted from small marine diesel engine become international problem, IMO(International Marine Organization) tried to establish severe regulations for NOx reduction. The formation of NOx is affected by cooling system, for instance, such as intercooler, heat exchanger, exhaust manifold, and therefore cooling systems are one of essential parts for design of small marine diesel engine. In this study, heat exchanger for small marine diesel engine was modeled and simulated using CATIA V5R19 and ANSYS FLUENT V.13. Thermal flow simulation for heat exchanger was performed to find the optimal design. As the results, maximum velocity of engine coolant in shell inside was 9.1m/s and it was confirmed that outlet temperature and temperature drop for engine coolant could be calculated by simulating proportional relations of temperature between engine coolant and sea water.

• Clean Technology
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• v.27 no.4
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• pp.332-340
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• 2021

With the recent reinforcement of emission standards, it is necessary to make efforts to reduce NOx from air pollutant-emitting workplaces. The NOx reduction method mainly used in industrial facilities is selective catalytic reduction (SCR), and the most commercial SCR catalyst is the ceramic honeycomb catalyst. This study was carried out to reduce the NOx emitted from steel plants by applying De-NOx catalyst coated on metallic monolith. The De-NOx catalyst was synthesized through the optimized coating technique, and the coated catalyst was uniformly and strongly adhered onto the surface of the metallic monolith according to the air jet erosion and bending test. Due to the good thermal conductivity of metallic monolith, the De-NOx catalyst coated on metallic monolith showed good De-NOx efficiency at low temperatures (200 ~ 250 ℃). In addition, the optimal amount of catalyst coating on the metallic monolith surface was confirmed for the design of an economical catalyst. Based on these results, the De-NOx catalyst of commercial grade size was tested in a semi-pilot De-NOx performance facility under a simulated gas similar to the exhaust gas emitted from a steel plant. Even at a low temperature (200 ℃), it showed excellent performance satisfying the emission standard (less than 60 ppm). Therefore, the De-NOx catalyst coated metallic monolith has good physical and chemical properties and showed a good De-NOx efficiency even with the minimum amount of catalyst. Additionally, it was possible to compact and downsize the SCR reactor through the application of a high-density cell. Therefore, we suggest that the proposed De-NOx catalyst coated metallic monolith may be a good alternative De-NOx catalyst for industrial uses such as steel plants, thermal power plants, incineration plants ships, and construction machinery.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.7
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• pp.1013-1018
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• 2008

For a sequential port fuel injection natural gas engine, its combustion and emission characteristics at low loads are crucial to meet light duty vehicle emission regulations. Fuel injection timing is an important parameter related to the mixture formation in the cylinder. Its effect on the combustion and emission characteristics of a natural gas engine were investigated at 0.2 MPa brake mean effective pressure (BMEP)/2000 rpm and 0.26 MPa BMEP/1500 rpm. The results show that early fuel injection timing is beneficial to the reduction of the coefficient of variation (COV) of indicated mean effective pressure (IMEP) under lean burn conditions and to extending the lean burn limits at the given loads. When relative air/fuel ratio is over 1.3, fuel injection timing has a relatively large effect on engine.out emissions. The levels of NOx emissions are more sensitive to the fuel injection timing at 0.26 MPa BMEP/1500 rpm. An early fuel injection timing under lean burn conditions can be used to control engine out NOx emissions.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.211-216
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• 2000

In this paper, experimental investigations were carried out to remove NOx, SOx simultaneously from a simulated combustion flue gas [$NO(0.02%)-SO_2(0.08%)-CO_2-Air-N_2$] by using a pulse corona induced plasma chemical processing. Discharge domain of wire-cylindrical plasma reactor was separated from a gas flow duct to avoid unstable discharge by aerosol particle deposited on discharge electrode and grounded electrode. The NOx, SOx removal was experimentally investigated by a reaction induced to ammonium nitrate, ammonium sulfate using a low price of aqueous NaOH solution and a small quantity of ammonia. Volume percentage of aqueous NaOH solution used was 20% and $N_2$ flow rate was $2.5{\ell}/min$ for bubbling aqueous NaOH solution. Ammonia gas(l4.82%) balanced by argon was diluted by air and was introduced to a main simulated flue gas duct through $NH_3$ injection system which was in downstream of reactor. The $NH_3$ molecular ratio(MR) was determined based on [$NH_3$] and [$NO+SO_2$]. MR is 1.5. The NOx removal rates increased in the order of DC, AC and pulse, but SOx removal rates was not significantly effected by source of electricity. The NOx removal rate slightly decreased with increasing initial concentration. but SOx removal rate was not significantly affected by initial concentration. The NOx, SOx removal rates decreased with increasing gas flow rate.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.105-111
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• 2012

Manganese (Mn) catalysts were generated using $CeO_2$ and $ZrO_2$supports synthesized by the supercritical hydrothermal method and two different Mn precursors, aimed at an application for a low-temperature selective catalytic reduction process. Manganese acetate (MA) and manganese nitrate (MA) were used as Mn precursors. Effects of the kind and the concentration of the Mn precursor used for catalyst generation on the NOx removal efficiency were investigated. The characteristics of the generated catalysts were analyzed using $N_2$ adsorption-desorption, thermo-gravimetric analysis, X-ray diffraction, and X-ray photoelectron spectroscopy. De-NOx experiments were carried out to measure NOx removal efficiencies of the catalysts. NOx removal efficiencies of the catalysts generated using MA were superior to those of the catalysts generated using MN at every temperature tested. Analyses of the catalyst characteristics indicated that the higher NOx removal efficiencies of the MA-derived catalysts stemmed from the higher oxygen mobility and the stronger interaction with support material of $Mn_2O_3$ produced from MA than those of $MnO_2$ produced from MN.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.789-798
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• 2011

We carry out an experimental investigation to analyze the basic performance of NO(nitric oxide) storage in a lean phase and also analyze the NO reduction achieved by the spraying of reducing agents in the rich phase of the exhaust gas in an LNT(Lean NOx Trap). This is an after-treatment system used to reduce the NOx emissions from a diesel engine. If the stored NO is reduced, we measure the outlet concentration downstream of the LNT. The test LNT material used in the experiments is commercial LNT. After being canned into stainless-steel(SUS304), it was built in a micro bench-flow reactor. Compositions of feed gases, three heated and three no heated gases were sprayed upstream of the LNT to analyze the characteristics. We use various temperatures and space velocities as response variables.