• Proceedings of the KSME Conference
• /
• 2001.06d
• /
• pp.979-984
• /
• 2001

As a preceding process for developing design technology and establishing operation technology, the design procedure of the SCR(Selective Catalytic Reduction) pilot plant that can handle $1,000Nm^{3}/hr$ of flue gas was reported in this paper. And we also considered several factors that might cause abnormality of the plant in the designing process. The plant was designed and fabricated to test the $DeNO_{x}$ performances in variable operating conditions in the range of $3,000{\sim}36,000hr^{-1}/hr$ in space velocities, $1.67{\sim}6\;m/s$ in linear velocities, $200{\sim}500^{\circ}C$ temperatures, $300{\sim}1,000Nm^{3}/hr$ flow rates, and $0{\sim}1.4:1\;NH_{3}/NO$ ratios. In order to maintain the flow uniformity, the guide vanes and flow straightener were designed and constructed in the plant. The SCR pilot plant can be operated by the automatic control system, which enable to obtain performance data in real time and to set up the operating technology. The catalyst reactor consists of 4 catalyst layers and surface area of each layer can be adjusted to be of small size. Arrangement of catalysts per layer is $3{\times}6$ with the catalyst dimensions of $150{\times}150{\times}500mm(L{\times}W{\times}H)$.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.4
• /
• pp.1923-1930
• /
• 2012

Mn-Cu catalysts were tested for selective catalytic reduction of NOx with NH3. Influence of initial reaction temperature was studied for NOx conversion in which reaction temperature was changed three patterns. NOx conversion of catalysts calcined at 200, 300 and $340^{\circ}C$ was measured during the changing temperature. Hydrogen conversion efficiency of calcined catalysts was also measured in the $H_2$-TPR system. The deactivation effect of $SO_2$ on catalyst was investigated with the on-off control of $SO_2$ supply. The catalyst which calcined above $340^{\circ}C$ was somewhat deactivated with thermal shock. The reason of deactivation was draw from the results of surface area and hydrogen conversion.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.5
• /
• pp.497-504
• /
• 2023

In this study, Selective catalytic reduction (SCR) + Diesel particulate filter (DPF) system was installed on a ship with a low-speed engine to conduct the on-board test. The target ship (2,881 gross tons, rated power 1,470 kW@240 rpm ×1) is a general cargo ship sailing in the coastal area. Drawing development, approvals and temporary survey of the ship were performed for the installation of the after-treatment system. For performance evaluation, the gaseous emission analyzer was used according to the NOx technical code and ISO-8178 method of measurement. The particulate matter analyzer used a smoke meter to measure black carbon, as discussed by the International Maritime Organization (IMO). Tests were conducted using MGO (0.043%) and LSFO (0.42%) fuels according to the sulfur content. The test conditions were selected by considering the engine rpm (130, 160 and 180). Gaseous emission and particulate matter (smoke) were measured according to the test conditions to confirm the reduction efficiency of the after treatment system. The results of NOx emission and particulate matter (smoke) revealed that reduction efficiency was more than 90%. The exhaust pressure met the allowable back pressure (less than 50 mbar). This study confirms the importance of the on-board test and the potential of SCR + DPF systems as a response technology for reducing nitrogen oxides and particulate matter.

• Journal of Power System Engineering
• /
• v.17 no.1
• /
• pp.19-26
• /
• 2013

The purpose of the study is carried out volume optimization of a combined system consisting of an LNT and SCR catalysts from the standpoint of its economic feasibility and de-NOx performance. Under the rich air-fuel ratio conditions for 5s (${\Phi}$=1.1), CO, $H_2$ and THC were generated at levels of 4%, 1.2% and $110ppmC_1$, respectively. The NOx conversion of the 1+1 combination was 5% lower than that of the 1.5+0.5 combination, however the reduced volume of the LNT catalyst decreased the total cost by about 6%. Therefore, the optimal volume ratio of the LNT and SCR catalysts was found to be the 1+1 catalyst combination, which has the highest total score in the terms of an economic feasibility and the NOx performance.

• Journal of Institute of Convergence Technology
• /
• v.7 no.1
• /
• pp.15-18
• /
• 2017

As emission gas regulation of deisel vehicles is strengthened to Euro-6, It becomes difficult to deal with NOx regulated value mainly by EGR without additional after-treatment system. In addition, RDE(Real Driving Emissions) test will be introduced after september 2017. Therefore, It is essential to develop the after-treatment of diesel vehicles which reduce NOx emissions. It is possible to use DOC, DPF, LNT or DOC, DPF and SCR as a after-treatment system for reducing NOx. However, It is expected that the SCR will be applied widely because LNT alone does not have sufficient NOx purification efficiency. In this study, It tried to analyze the efficiency of reducing NOx emissions during the mode test by attaching a NOx sensor to test vehicle. As a result, It was confirmed that NOx emissions was significantly reduce through the after-treatment system from engine. And the NOx reduction efficiency of SCR was about 4.5 times better than DOC, DPF.

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

• Journal of the Korea Convergence Society
• /
• v.10 no.4
• /
• pp.131-138
• /
• 2019

Diesel engines have important advantages over its gasoline counterpart including high thermal efficiency, high fuel economy and low emissions of CO, HC and $CO_2$. However, NOx reducing is more difficult on diesel engines because of the high $O_2$ concentration in the exhaust, marking general three way catalytic converter ineffective. Two method available technologies for continuous NOx reduction onboard diesel engines are Urea-SCR and LNT. The implementation of the Urea-SCR systems in design engines have made it possible for 2.5l and over engines to meet the tightened NOx emission standard of Euro-6. In this study, we investigate the characteristics of NOx reduction with respect to engine speed, load, types of catalyst and the $NH_3$/NOx ratio and present the conditions which maximize NOx reduction. Also we provide detailed experimental data on Urea-SCR which can be used for the preparation for standards beyond Euro-6.

• Journal of Power System Engineering
• /
• v.13 no.4
• /
• pp.5-10
• /
• 2009

Urea-SCR system, the selective catalytic reduction using urea as reducing agent, is a powerful technique to reduce nitrogen oxides(NOx) emitted from diesel engines. However, a tank of urea(32.5 wt%)-water solution can be frozen in low ambient temperature levels of below $-11^{\circ}C$. The purpose of this study is to understand freezing and melting phenomena of the urea-water solution, and its can be applied to get the urea-water solution from frozen it within 5 minutes after cold start. Factors considered were the type of heater and the urea tank shape. From the results, it was found that melting volume of cartridge heater B during 5 minutes of heating period was 83ml when supplying electric power of 150W. Horizontal heater B, which was put in the narrow bottom space of the tank T1, had fast melting characteristics.

• 한국연소학회:학술대회논문집
• /
• 2007.05a
• /
• pp.98-103
• /
• 2007

The number of vehicles employing diesel engines is rapidly rising. Accompanying this trend, application of an after-treatment system is strictly required as a result of reinforced exhaust regulations. The Diesel Particulate Filter (DPF) system is considered as the most efficient method to reduce particulate matter (PM), but the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Temperature, gas compostion and flow rate of exhaust gas are important parameters in DPF evaluation, especially regeneration process. Engine dynamometer and degment tester are generally used in DPF evaluation so far. But these test method couldn't reveal the effect of various parameters on real DPF, such as O2 concentration, amount of soot and exhaust gas temperature. This research has studied the possibility using dump combustor that used to take an approach lean premixed combustion in gas turbine for a DPF power and optimized. It is possible that utilize the system as DOC (Diesel Oxidation Catalyst) and SCR(Selective Catalytic Reduction) assessments test as well as DPF evaluation

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.2 s.257
• /
• pp.167-172
• /
• 2007

A new method that optimizes a control of hydrocarbon (HC) addition to diesel exhaust gas for HC type DeNOx catalyst system has been developed. These catalysts are called the HC-DeHOx catalyst in this paper. The system using HC-DeNOx catalyst requires a resonable quantity of hydrocarbons addition in the inlet gas of the catalyst, because the HC concentration in a diesel engine is so low that the HC is not sufficient for NOx conversion. It is expected that this study offers a robust data developing HC injection system.