船用柴油机SCR系统控制策略试验研究
李文听1,谢宗序2,郑添1
1.中船重工第七〇三研究所无锡分部,江苏 无锡 214000;2.中国核电工程有限公司华东分公司,浙江 嘉兴 314300
摘要:为降低船用柴油机NOx排放,分析柴油机选择性催化还原(selective catalytic reduction,SCR)后处理系统的开环、闭环控制策略,对不同策略及工况下NOx转化率及NH3泄露进行试验对比。结果表明:采用开环策略,柴油机功率与额定功率的比为75%以上时,NOx转化效率可达到83%,但不同工况下NOx转化率波动超过20%;采用闭环控制策略,不同工况下NOx转化率稳定在85%左右,尾气中NH3的体积分数低于20×10-6;闭环控制策略下NOx转化率具有自调整、高稳定性、响应速度快等优势,可降低NOx排放且尾气中NH3的体积分数在规定范围内。
关键词:SCR系统;开环控制;闭环控制;NOx排放
Experimental study on SCR control strategy for a marine diesel engine
LI Wenting1, XIE Zongxu2, ZHENG Tian1
1.Wuxi Division, NO.703 Research Institute of CSSC, Wuxi 214000, China;
2.East China Branch, China Nuclear Power Engineering Co., Ltd., Jiaxing 314300, China
Abstract: In order to reduce marine diesel engines NOxemission, the open-loop and closed-loop control strategies of the diesel selective catalytic reduction aftertreatment system are analyzed, the NOx conversion and NH3 leakage under different strategies and operating conditions are compared. The results show that with the open-loop control, when the load ratio of diesel engine is above 75% , the NOx conversion efficiency can reach 83%, but the fluctuation of NOx conversion is more than 20%. With the closed-loop control strategy, the conversion of NOx is stable at about 85% , and the volume fraction of NH3 leakage is less than 20×10-6 under different operating conditions. The closed-loop control strategy has the advantages of self-adjustment of NOx conversion, high stability and fast response speed, which can reduce NOxemission and NH3 leakage volume fraction within the specified range.
Keywords: SCR system; open-loop control; closed-loop control; NOx emission