• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.125-126
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• 2012

The key issues for the reduction technologies of the exhaust gas from diesel engine being developed are to reduce particulate matters and NOx. Performance of NOx removal in SCR process depends on such various factors as catalyst factors(catalyst composition, shape, velocity, etc.), exhaust gas temperature and velocity distribution. In this study checked flow uniformity with the flow characteristics in the SCR reactor by using STAR CCM+. The pressure drop of experiment and simulation had similar result more than 90% at catalytic Cell. Also, flow uniformity calculated about 0.9036 ant 1st catalytic ind SCR reactor.

• Journal of the Korean Society of Visualization
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• v.19 no.1
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• pp.62-67
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• 2021

Selective catalytic reduction(SCR) is an exhaust gas reduction device to remove nitro oxides (NOx). SCR operation of ship can be controlled through valves for minimizing economic loss from SCR. Valve in SCR-high pressure (HP) system is directly connected to engine exhaust and operates in high temperature and high pressure. Long-term thermal deformation induced by engine heat weakens the sealing of the valve, which can lead to unexpected failures during ship sailing. In order to prevent the unexpected failures due to long-term valve thermal deformation, a failure prediction system using autoregressive integrated moving average (ARIMA) was proposed. Based on the heating experiment, virtual data mimicking temperature range around the SCR-HP valve were produced. By detecting abnormal temperature rise and fall based on the short-term ARIMA prediction, an algorithm determines whether present temperature data is required for failure prediction. The signal processed by the data collection algorithm was interpolated for the failure prediction. By comparing mean average error (MAE) and root mean square error (RMSE), ARIMA model and suitable prediction instant were determined.

• Journal of the Korean Society of Visualization
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• v.22 no.3
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• pp.21-28
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• 2024

The study investigates the application of Selective Catalytic Reduction (SCR) systems in steel manufacturing processes. To calculate the pressure drop occurring in the SCR system's catalytic plates under various operating conditions, we assumed a porous filter model. The pressure drop along the gas flow path is determined by theoretical calculations and computational simulations. The discrepancy in the data obtained from the both approach happens in the region of curved sections of SCR system where secondary flows occur. The pressure drop was calculated depending on different flow rate, by which a correlation between the pressure drop and the flow rate was made based on the simulation results. Inside the SCR system, boundary layer separation occurs before the SCR chamber, causing the flow to deviate in one direction. As a result, the flow uniformity decreases in the SCR chamber, which could lead to a decrease in the reaction performance on the catalytic plates. By installing baffles at the inlet region of the SCR chamber, the uniformity is enhanced by around 18.8% based on the standard deviation.

• Journal of the Korean Society of Combustion
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• v.12 no.3
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• pp.16-23
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• 2007

Employing an after-treatment system has almost become a mandatory requirement for Diesel vehicles, which results from a reinforced exhaust regulations as the number of vehicles powered by a Diesel engine increases. The Diesel Particulate Filter (DPF) system is considered as one of the most efficient method to reduce particulate matter (PM); however, the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Temperature, gas composition and flow rate of exhaust gas are important parameters in DPF evaluation processes, especially during a regeneration process. Engine dynamometer and segment tester are generally used in DPF evaluation so far. These test methods, however, could not completely evaluate the effect of various parameters on real DPF, such as oxygen concentration, amount of soot and exhaust gas temperatures. The evaluation of DPF systems using a dump combustor has been verified experimentally and this dump combustor system is likely to be appropriate for the DOC (Diesel Oxidation Catalyst) and SCR (Selective Catalytic Reduction) assessments test, too.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.368-377
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• 2011

A package type of SCR (selective catalytic reduction) system that was proposed for removing the $NO_x$ found in flue gas from the small scale of air pollution sources was evaluated. The efficiency of the SCR system is determined by the proper utilization of catalytic media installed inside of the system, and the proper distribution of flow velocity and $NH_3$ concentration in the flue gas is a crucial factor for using the catalytic media. In this study, the distributions of $NH_3$ concentration were estimated under the various arrays and shapes of AIG at the given gas flow condition. The value of RMS (%) in $NH_3$ concentration is 95.3% at co-current flow (at $0^{\circ}$) injection but it is 90.1% at the condition of counter-current flow (at $120^{\circ}$) condition, which implies the counter-current injection is more favorable. By rearranging the $NH_3$ injection flow rates based on the distribution of velocity and $NH_3$ distribution in basic calculation, the value of RMS (%) in $NH_3$ concentration was reduced to 62.8%. The enhanced effect of $NH_3$ mixing by the combined effect of arrays and shapes are complied in the study.

• Particle and aerosol research
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• v.8 no.3
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• pp.99-110
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• 2012

In the SCR (selective catalytic reduction) system which is used for controlling the NOx emission from the Diesel engines, the soot deposited on the catalysis causes degradation of the system performance. Numerical study was done to evaluate the performance of soot blower which is proposed as a method for removing the soot on the catalysis. The spray conditions and the effect of the compressed air from the AIG (air inlet gun) were analyzed numerically to evaluate the overall effective method of the soot blowing. The characteristics of the final velocity distribution and velocity waves across the inlet section of the catalysis were evaluated with respect to the geometries of the AIG outlets and pressure conditions. An experimental model was used to validate the results of the numerical calculation that is used for finding the effective removal blowing momentum transfer quantities of soot the inlet section of the catalysis, and it is proposed that the required minimum blowing momentum transfer quantities are over than 0.499 $kg/m{\bullet}t_{eff}$ in the current study.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.153-158
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• 2019

The overall environmental regulations of the industry have been strengthened due to environmental pollution that occurred in modern society. Therefore, R&D of selective reduction catalyst (SCR) is needed to meet these environmental regulations. This paper carried out thermal analysis to develop the pneumatic damper valve (PDV), which is a key component of SCR system. For thermal analysis, verification of material properties was performed first. Verification was performed through the thermal properties test and the thermal tensile test of the specimen, and the results were reinforced with the material properties to enhance the reliability of the thermal analysis.The heat analysis was intended to identify thermal characteristics with PDV in total of three materials (SM400B, SS275, SB410) applied under the conditions of use of PDV, and to confirm the structural stability of the PDV.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.73-82
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• 2012

The main and side reactions of the three selective catalytic reduction (SCR) reactions with ammonia over a vanadium-based catalyst have been investigated using synthetic gas mixtures in the temperature range of $170{\sim}590^{\circ}C$. The three SCR reactions are standard SCR with pure NO, fast SCR with an equimolar mixture of NO and $NO_2$, and $NO_2$ SCR with pure $NO_2$. Vanadium based catalyst has no significant activity in NO oxidation to $NO_2$, while it has high activity for $NO_2$ decomposition at high temperatures. The selective catalytic oxidation of ammonia and the formation of nitrous oxide compete with the SCR reactions at the high temperatures. Water strongly inhibits the selective catalytic oxidation of ammonia and the formation of nitrous oxide, thus increasing the selectivity of the SCR reactions. However, the presence of water inhibits the SCR activity, most pronounced at low temperatures. In this study, the experimental results are analyzed by means of a dynamic one-dimensional isothermal heterogeneous plug-flow reactor (PFR) model according to the Eley-Rideal mechanism.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.95-105
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• 2012

The selective catalytic reduction (SCR) system is a highly-effective aftertreatment device for NOx reduction of diesel engines. Generally, the ammonia ($NH_3$) was generated from reaction mechanism of SCR in the SCR system using the liquid urea as the reluctant. Therefore, the precise urea dosing control is a very important key for NOx and $NH_3$ slip reduction in the SCR system. This paper investigated NOx and $NH_3$ emission characteristics of urea-SCR dosing system based on model-based control algorithm in order to reduce NOx. In the map-based control algorithm, target amount of urea solution was determined by mass flow rate of exhaust gas obtained from engine rpm, torque and $O_2$ for feed-back control NOx concentration should be measured by NOx sensor. Moreover, this algorithm can not estimate $NH_3$ absorbed on the catalyst. Hence, the urea injection can be too rich or too lean. In this study, the model-based control algorithm was developed and evaluated on the numerical model describing physical and chemical phenomena in SCR system. One channel thermo-fluid model coupled with finely tuned chemical reaction model was applied to this control algorithm. The vehicle test was carried out by using map-based and model-based control algorithms in the NEDC mode in order to evaluate the performance of the model based control algorithm.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3096-3101
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• 2008

Selective Catalytic Reduction (SCR) technology is well-known to be effective for the reduction of NOx emission. So car manufacturers has adopted Ures-SCR system to be satisfied with emission regulation. This paper discusses the effective of $NH_3/NOx$ ratio and SCR catalyst temperature in the $NH_3$-SCR reactor on DeNOx performance. So it is shown the characteristic of NOx conversion and ammonia slip using the $NH_3$ instead of Urea-Solution. From the result of this study, it is found to optimize $NH_3/NOx$ ratio to have the best case of high NOx conversion and low ammonia slip at variable SCR catalyst temperatures. Lastly, it is also found the characteristics of NOx conversion and ammonia slip with compared with Urea.