Study on Urea Crystallization Risk Assessment and Influencing Factors in After-Treatment System of Diesel Engines
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Published:2024-01-13
Issue:2
Volume:14
Page:684
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ISSN:2076-3417
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Container-title:Applied Sciences
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language:en
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Short-container-title:Applied Sciences
Author:
Sun Ke1, Zhang Gecheng1ORCID, Zhao Kui1, Sun Wen1, Li Guoxiang1, Bai Shuzhan1, Lin Chunjin2, Cheng Hao3
Affiliation:
1. School of Energy and Power Engineering, Shandong University, Jinan 250061, China 2. Geotechnical and Structural Engineering Research Center, Shandong University, Jinan 250061, China 3. School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
Abstract
In order to meet the increasing pollutants discharge standard, the selective catalytic reduction (SCR) module in the diesel engine after-treatment system is an important means to reduce nitrogen oxide (NOx) emissions. SCR systems are prone to urea crystallization at lower temperatures, especially during the cold-start conditions of diesel engines. In this study, we use the diesel engine after-treatment system test bench to obtain the boundary parameter of the simulation modules, and the urea crystallization risk assessment model of the diesel SCR system is established. Comparing the computational fluid dynamics (CFD) results with the test bench results, it is shown that the predicted urea film distribution of the assessment model is in good agreement with the experimental results. In order to clarify the various factors that affect the urea crystallization risk, this paper conducts a simulation analysis on a nozzle and mixer structure and operating parameters. The CFD results indicate that the increase in urea spray time will increase the maximum urea film thickness on the SCR system mixer surface. Exhaust temperature is the most important influencing factor. When the diesel engine exhaust temperature increases from 190 °C to 300 °C, the maximum urea film thickness decreases by 32 and the urea film mass accumulation decreases by 5%. Exhaust flow has a small impact on urea crystallization risk. When the exhaust flow increases from 300 kg/h to 600 kg/h, the maximum urea film thickness decreases by 39% and the urea film mass accumulation decreases by about 1%. In addition, urea spray rate, nozzle numbers, spray angle, and spray cone angle are also factors that affect urea crystallization risk.
Funder
Construction Machinery Intelligent Equipment Innovation and Entrepreneurship Community of Shandong, China Department of Science & Technology of Shandong Province, China Asset & Laboratory Management Department of Shandong University, China the Undergraduate School of Shandong University, China
Subject
Fluid Flow and Transfer Processes,Computer Science Applications,Process Chemistry and Technology,General Engineering,Instrumentation,General Materials Science
Reference26 articles.
1. Johnson, T., and Joshi, A. (2017, January 4–6). Review of Vehicle Engine Efficiency and Emissions. Proceedings of the WCX™ 17: SAE World Congress Experience, Detroit, MI, USA. 2. An Experimental Investigation of the Performance and Emissions of a Hydrogen-Diesel Dual Fuel Compression Ignition Internal Combustion Engine;Castro;Appl. Therm. Eng.,2019 3. Hydrogen effects on the diesel engine performance and emissions;Koten;Int. J. Hydrogen Energy,2018 4. Effects of Private Electric Vehicles on Carbon Emission Reduction in China during Whole Life Cycle;Zixian;Res. Environ. Sci.,2021 5. Li, Y., Ha, N., and Li, T. (2019). Research on Carbon Emissions of Electric Vehicles throughout the Life Cycle Assessment Taking into Vehicle Weight and Grid Mix Composition. Energies, 12.
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