JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE) ›› 2017, Vol. 47 ›› Issue (4): 70-76.doi: 10.6040/j.issn.1672-3961.0.2017.047

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Analysis and optimization of urea deposits formation in urea-SCR systems

BAI Fengyue, WEN Bangyao, BAI Shuzhan*   

  1. School of Energy and Power Engineering, Shandong University, Jinan 250061, Shandong, China
  • Received:2017-02-08 Online:2017-08-20 Published:2017-02-08

Abstract: Urea crystallization in the urea selective catalytic reduction(urea-SCR)system was analyzed by detecting the components of the deposits with thermo-gravimeter-fourier transform infrared spectroscopy(TG-FTIR)technology and simulating the air motion in the exhaust system with computational fluid dynamics(CFD)technology. To solve the problem of urea solution hitting the wall and poor atomization, the integral nozzle mountings structure and integrated nozzle seat package structure were put forward based on the CFD results, and the exhaust temperature when it started to spray and the injection rate of urea solution were optimized with engine bench tests. The results indicated that there were no urea deposits in the optimized structures when the exhaust temperature reached 272 ℃ or the injection rate of urea solution reached 5 g/min, thus solved the urea crystallization problem, which could provide effective methods for design and optimization of SCR systems for diesel engines.

Key words: urea deposition, urea-SCR system, urea injection strategy, diesel engine, structural optimization

CLC Number: 

  • TK421.5
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