融合CFD与PI控制的船舶柴油机SCR脱硝系统设计与分析

SCR-DeNO_X System Design and Analysis for Marine Diesel Based on CFD and PI Algorithm

选择性催化还原技术对氮氧化物脱除具有显著效果,是当前广泛使用的脱硝处理技术。文章从介观角度出发,采用CFD方法建立船用SCR脱硝系统的物理模型,分析SCR脱硝系统的反应机理,并通过用户自定义函数将PI控制算法融合进介观系统模型中,摒弃传统控制模型中的均匀分布假设,实现介观尺度上的非均匀喷氨控制。仿真测试结果表明:船用SCR脱硝系统的气体分布呈现严重非均匀性;融合介观尺度上PI控制算法后,不仅可改善系统的非均匀性,还可提高系统的整体脱硝率,降低系统的氨逃逸量。研究结果可为宏观控制与介观机理建模的融合提供新的研究思路。

The selective catalytic reduction technology has a significant effect on the removal of nitrogen oxides and is widely used in denitrafication systems. A mechanism model of a certain marine SCR denitrafication system is established with CFD method, which is from mesoscopic point of view. And then, reaction mechanisms of the SCR denitrafication system is analyzed. The PI algorithm is integrated into the CFD model by user-defined function, in which the homogeneous hypothesis for the mixed gases adopted in traditional control models is abandoned. Simulation results show that the gas distribution in the marine diesel SCR denitrification system presents a high non-uniformity. The fusion of mesoscale PI algorithm can not only improve the non-uniformity of the system, but also improve the overall denitrafication rate and reduce the ammonia slip of the system. The research results can provide new research ideas for the fusion of macroscopic control and mesoscopic models.