Reduction of NOx emissions from diesel engines by solid SCR technology
LIU Yingshuai1,2,3,, HU Guangdi1,,, QI Baohua2 1.School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, China 2.Ningbo Free Trade Zone Workstation, Ningbo 315899, China 3.Institute of Intelligent Manufacturing, Weifang University of Science & Technology, Weifang 261000, China
Abstract:The urea-SCR technology is prone to low NOx conversion efficiency and urea crystallization in the low exhaust temperature actual operation process of the vehicle. To address this, engine test bench studies are conducted to investigate the effectiveness of solid SCR technology on NOx emission reduction. Results show that the volume of the solid SCR system is only 1/3 of the urea-SCR when carrying the same amount of reductant. The NOx conversion efficiency of the solid SCR system reaches 40% when the exhaust temperature is 160 ℃. Based on the same ammonia nitrogen ratio setting, the NOx conversion efficiency improves by 3.3% and 4.5% by applying the WHSC and WHTC cycles respectively. The NOx conversion efficiency improves significantly when the starting temperature of the solid SCR is reduced to 160 ℃, which is 9.7% and 15.5% higher than that of the solid SCR system and urea-SCR systems at 200 ℃, respectively. The emission of NOx pollutants from diesel vehicles with the urea-SCR system is significantly higher, which is 2.38 and 1.73 times that of solid SCR system with injection temperature at 160 ℃ and 200 ℃ according to the work based windows analysis ((0, 20]). Key words:selective catalytic reduction/ exhaust emission of diesel engine/ leakage of ammonia/ conversion efficiency/ metal ammine chloride salts.
图1固态SCR系统工作示意图 Figure1.Schematic diagram of solid SCR system
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1.School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, China 2.Ningbo Free Trade Zone Workstation, Ningbo 315899, China 3.Institute of Intelligent Manufacturing, Weifang University of Science & Technology, Weifang 261000, China Received Date: 2020-05-13 Accepted Date: 2020-10-10 Available Online: 2021-02-22 Keywords:selective catalytic reduction/ exhaust emission of diesel engine/ leakage of ammonia/ conversion efficiency/ metal ammine chloride salts Abstract:The urea-SCR technology is prone to low NOx conversion efficiency and urea crystallization in the low exhaust temperature actual operation process of the vehicle. To address this, engine test bench studies are conducted to investigate the effectiveness of solid SCR technology on NOx emission reduction. Results show that the volume of the solid SCR system is only 1/3 of the urea-SCR when carrying the same amount of reductant. The NOx conversion efficiency of the solid SCR system reaches 40% when the exhaust temperature is 160 ℃. Based on the same ammonia nitrogen ratio setting, the NOx conversion efficiency improves by 3.3% and 4.5% by applying the WHSC and WHTC cycles respectively. The NOx conversion efficiency improves significantly when the starting temperature of the solid SCR is reduced to 160 ℃, which is 9.7% and 15.5% higher than that of the solid SCR system and urea-SCR systems at 200 ℃, respectively. The emission of NOx pollutants from diesel vehicles with the urea-SCR system is significantly higher, which is 2.38 and 1.73 times that of solid SCR system with injection temperature at 160 ℃ and 200 ℃ according to the work based windows analysis ((0, 20]).