某船用柴油机SCR系统匹配性能试验分析

针对某船用柴油机,在D2试验循环模式下进行原机和加装SCR系统后的性能对比试验,分析SCR反应器在无尿素喷射时对柴油机排气特性和经济性的影响,同时还分析按氮氨比为1∶1进行尿素喷射时SCR系统的工作性能。试验结果表明:柴油机安装SCR系统后,排气背压和排气温度均有所上升;经济性略有下降,额定工况下降低幅度在1%左右;虽然增压器后NOX排气浓度增大,但NOX质量流量下降幅度较大,额定工况下降幅度为12.3%,尿素基本喷射量标定计算应以加装SCR反应器后的柴油机排气参数为依据;NOX加权比排放由原机的12.63 g/k Wh降低到11.52 g/k Wh,降低了8.7%。按氮氨比为1∶1的比例进行尿素喷射时,SCR系统能满足Tire III的NOX排放限值要求。研究结果可为SCR系统设计和尿素喷射量的标定提供一定的指导依据。

Experimental Study on Matching Performance of SCR System for a Marine Diesel Engine

An experimental study was conducted to analyze the effects of SCR (Selective Catalytic Reduction) on exhaust emissions and engine performance characteristics of a marine diesel engines in D2 cycle (generation application). Meanwhile, the performance of the SCR emission control systems was evaluated. The results show that the EBP (exhaust back pressure) and temperature of the engine with SCR catalyst, compared those without SCR catalyst, are risen; the fuel consumption rate is increased by about 1% at 100% power condition point. Although the concentration of NOx is increased, the mass flow of NOx can be reduced by about 12.3% at 100% power condition point. The injecting mass of urea should be calculated on the emission parameters of marine diesel engines with SCR. The specific emission of NOx decreases from 12.63g/kWh to 11.52g/kWh, decreased by 8.7%.When the proportion of NH3 and NOx is 1:1 ratio, the NOx emission from the engine with SCR reactor meet requirement for Tire III. Those test results could give reference for SCR system design and the calibration of urea.