Investigation on the urea deposits formation in the selective catalyst reduction system of a marine high-power engine

IF 5.5 3区工程技术 Q1 ENGINEERING, CHEMICAL Journal of the Taiwan Institute of Chemical Engineers Pub Date : 2025-03-08 DOI:10.1016/j.jtice.2025.106075

Chong Xia , Yuanqing Zhu , Diantao Liu , Song Zhou , Yongming Feng , Jie Shi , Ang Sun , Kai Zhu

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Abstract

Background

The incomplete decomposition of urea to form urea deposits is a major problem in the application of engine selective catalytic reduction (SCR) technology. To improve the NOx reduction rate of the SCR system, it is necessary to suppress the formation of urea deposits.

Methods

The high-pressure SCR system of a 20 MW marine low-speed two-stroke diesel engine was taken as a research object. The positions and shapes of urea deposits formed within the SCR system were investigated through sea navigation experiments. Then, various characterization techniques were used to detect the chemical composition of urea deposits in different regions. Finally, a comprehensive computational fluid dynamics (CFD) simulation method was introduced to model the injection of urea-water solution (UWS), droplet collision, and the formation of urea deposits.

Significant findings

The main chemical composition of urea deposits was cyanuric acid (cya, C₃H₃N₃O₃) and ammelide (C₃H₄N₄O₂). The simulation results indicated a high level of consistency between the predicted shape, location, and chemical composition of urea deposits and the experimental findings. After adjusting the installation direction of the static mixer, the deposition rate of the liquid film was reduced by about 50%, and the formation of cya and ammelide was effectively suppressed.

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来源期刊

Journal of the Taiwan Institute of Chemical Engineers 工程技术-工程：化工

CiteScore

9.10

自引率

14.00%

发文量

362

审稿时长

35 days

期刊介绍： Journal of the Taiwan Institute of Chemical Engineers (formerly known as Journal of the Chinese Institute of Chemical Engineers) publishes original works, from fundamental principles to practical applications, in the broad field of chemical engineering with special focus on three aspects: Chemical and Biomolecular Science and Technology, Energy and Environmental Science and Technology, and Materials Science and Technology. Authors should choose for their manuscript an appropriate aspect section and a few related classifications when submitting to the journal online.