Abstract
Urea-Selective Catalytic Reduction (SCR) is widely used to reduce nitrogen oxide (NOx) emissions. This paper presents a comprehensive experimental research work on aftertreatment emissions of NOx and ammonia (NH3) slip for three aftertreatment concepts by introducing the SCR sizing strategy on a 6-cylinder mid-range non-exhaust gas recirculation (EGR) diesel engine to meet China non-road Stage IV regulation limits. It can be observed that the three concepts could meet the regulation limits for NOx emissions and NH3 slip by selecting the appropriate length. There is little effect on emission results during a non-road transient cycle (NRTC) when the aftertreatment inlet/outlet with insulation and without insulation and the emission results on both strategies could meet non-road China Stage IV regulation limits. It is recommended to select Concept 2 which could meet regulation requirements considering multiple factors in the SCR sizing strategy. Substrate impact and NH3/NOx molar ratio (ANR) impact are investigated based on Concept 2. The results show that by applying the SCR substrate aftertreatment with a cell density of 600 cpsi, NOx conversion capability is stronger than that with cell density 400 cpsi for the same SCR size. Current dosing strategy is capable and recommended ANR is 0.9–1.1 if considering dosing strategy optimization. The methodology in this study provides an effective guidance and reference for future aftertreatment SCR sizing strategies in real applications.
Highlights
China proposed new non-road Stage IV emission regulations that preliminarily states that for engines with powers within a 130 kW to 560 kW range, the system nitrogen oxide (NOx) emission limit should be 2.0 g/kWh, the NH3 slip limit 25 ppm, and the particle matter (PM) limit 0.025 g/kWh, while a particle number (PN) requirement is added, with a limitation of 5 × 1012 [1]
China proposed new non-road Stage IV emission regulations that preliminarily states that for engines with powers within a 130 kW to 560 kW range, the system NOx emission limit should be 2.0 g/kWh, the NH3 slip limit 25 ppm, and the particle matter (PM) limit 0.025 g/kWh, while a particle number (PN) requirement is added, with a limitation of 5 × 1012 [1]. Fulfilling this strict emission regulation in non-road diesel engines requires a complex aftertreatment with a Diesel oxidant catalyst (DOC) + Diesel particle filter (DPF) + selective catalytic reduction (SCR) scheme [2]
SCR catalyst performance degradation was validated after long use in real world application due catalyst performance degradation was validated after long use application
Summary
China proposed new non-road Stage IV emission regulations that preliminarily states that for engines with powers within a 130 kW to 560 kW range, the system NOx emission limit should be 2.0 g/kWh, the NH3 slip limit 25 ppm, and the particle matter (PM) limit 0.025 g/kWh, while a particle number (PN) requirement is added, with a limitation of 5 × 1012 [1]. Fulfilling this strict emission regulation in non-road diesel engines requires a complex aftertreatment with a Diesel oxidant catalyst (DOC) + Diesel particle filter (DPF) + selective catalytic reduction (SCR) scheme [2]. To achieve low NOx emissions, an integrated control strategy involving a Energies 2020, 13, 4462; doi:10.3390/en13174462 www.mdpi.com/journal/energies
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