不同催化剂负载量柴油机颗粒捕集器的性能研究

Performance of Diesel Particulate Filter Under Different Catalyst Loadings

摘要:

柴油机颗粒捕集器（diesel particulate filter，DPF）是减少柴油机颗粒排放的高效技术手段，其性能与催化剂负载量密切相关。基于重型柴油机台架试验系统研究催化剂负载量对催化型柴油机颗粒捕集器（catalyzed diesel particulate filter，CDPF）压降、气态物及颗粒物减排性能的影响并结合CDPF再生探究其对NO的氧化特性的影响。结果表明：CDPF排气背压随催化剂负载量的增大呈线性增大趋势，当催化剂负载量从0 g/ft³分别增至5、10、20 g/ft³（1 ft³=0.0283 m³）时，平均排气背压从2.94 kPa依次增大至3.44、3.96和4.51 kPa。催化剂负载量越高，CDPF对CO和总碳氢化合物（total hydrocarbon，THC）的减排效果越好。当催化剂负载量从0 g/ft³分别增至5、10、20 g/ft³时，CO排放浓度从78.94×10^-6依次降至71.39×10^-6、68.12×10^-6和63.30×10^–6，THC排放浓度则从57.34×10^–6依次降至48.31×10^–6、46.93×10^–6和44.51×10^–6。催化剂负载量会显著影响NO氧化特性，但对NO_x排放浓度的影响较小。CDPF可以实现95%以上的颗粒物（particulate matter，PM）和颗粒物数量（particulate number，PN）减排率，增大催化剂负载量，CDPF颗粒减排效果有所提高，核态颗粒减排效果提升更为显著。研究结果对设计高性能CDPF具有重要参考价值。

Abstract:

The diesel particulate filter is an effective technology to reduce diesel particulate emissions, and its performance is closely related to catalyst loading. Based on the platform test system of heavy diesel engine, the influence of catalyst amount on the pressure drop, gas state and particulate emission reduction performance of diesel CDPF regeneration was studied. The results show that the exhaust back pressure of catalyst increases linearly with the increase in catalyst loading. When catalyst loading increases from 0 g/ft³ to 5, 10 and 20 g/ft³(1 ft³=0.0283 m³), the average exhaust back pressure increases from 2.94 kPa to 3.44, 3.96 and 4.51 kPa, respectively. The larger the amount of catalyst, the better the emission reduction effect of the catalytic converter on CO and total hydrocarbon (THC). When catalyst loading increases from 0 g/ft³ to 5, 10 and 20 g/ft³, CO emission decreases from 78.94×10^–6 to 71.39×10^–6, 68.12×10^–6 and 63.30×10^–6, and THC emission concentration decreases from 57.34×10^–6 to 48.31×10^–6, 46.93×10^–6 and 44.51×10^–6, respectively. The amount of catalyst has a significant effect on NO oxidation, but not on NO_x emission concentration. Catalyzed diesel particulate filter (CDPF) can achieve a reduction rate of more than 95% for particulate matter and particulate number. Increasing catalyst loading improves the particulate emission reduction effect of CDPF, with a more significant improvement in the reduction effect of nucleation particles. The results of this study have important reference value for the design of high-performance CDPF.