Book Synopsis AN EXPERIMENTAL INVESTIGATION OF THE EFFECT OF TEMPERATURE AND SPACE VELOCITY ON THE PERFORMANCE OF A CU-ZEOLITE FLOW-THROUGH SCR AND A SCR CATALYST ON A DPF WITH AND WITHOUT PM LOADING by :
Download or read book AN EXPERIMENTAL INVESTIGATION OF THE EFFECT OF TEMPERATURE AND SPACE VELOCITY ON THE PERFORMANCE OF A CU-ZEOLITE FLOW-THROUGH SCR AND A SCR CATALYST ON A DPF WITH AND WITHOUT PM LOADING written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Abstract The heavy-duty diesel (HDD) engines use the diesel oxidation catalyst (DOC), catalyzed particulate filter (CPF) and urea injection based selective catalytic reduction (SCR) systems in sequential combination, to meet the US EPA 2010 PM and NOx emission standards. The SCR along with a NH3 slip control catalyst (AMOX) offer NOx reduction >90 % with NH3 slipHowever, there is a strong desire to further improve the NOx reduction performance of such systems, to meet the California Optional Low NOx Standard implemented since 2015. Integrating SCR functionality into a diesel particulate filter (DPF), by coating the SCR catalyst on the DPF, offers potential to reduce the system cost and packaging weight/ volume. It also provides opportunity to increases the SCR volume without affecting the overall packaging, to achieve NOx reduction efficiencies >95 %. xvii In this research, the NOx reduction and NH3 storage performance of a Cu-zeolite SCR and Cu-zeolite SCR catalyst on DPF (SCRF®) were experimentally investigated based on the engine experimental data at steady state conditions. The experimental data for the production-2013-SCR and the SCRF® were collected (with and without PM loading in the SCRF®) on a Cummins ISB 2013 engine, at varying inlet temperatures, space velocities, inlet NOx concentrations and NO2/NOx ratios, to evaluate the NOx reduction, NH3 storage and NH3 slip characteristics of the SCR catalyst. The SCRF® was loaded with 2 and 4 g/L of PM prior to the NOx reduction tests to study the effect of PM loading on the NOx reduction and NH3 storage performance of the SCRF®. The experimental setup and test procedures for evaluation of NOx reduction performance of the SCRF®, with and without PM loading in the SCRF® are described. The 1-D SCR model developed at MTU was calibrated to the engine experimental data obtained from the seven NOx reduction tests conducted with the production-2013-SCR. The performance of the 1-D SCR model was validated by comparing the simulation and experimental data for NO, NO2 and NH3 concentrations at the outlet of the SCR. The NO and NO2 concentrations were calibrated to ±20 ppm and NH3 was calibrated to ±20 ppm. The experimental results for the production-2013-SCR indicate that the NOx reduction of 80 - 85% can be achieved for the inlet temperatures below 250°C and above 450°C and NOx reduction of 90 - 95% can be achieved for the inlet temperatures between 300 - 350°C, at ammonia to NOx ratio (ANR) 1.0, while the NH3 slip out of the SCR wasConversely, the SCRF® showed 90 - 95 % NOx reduction at ANR of 1.0, while the NH3 slip out of the SCRF® was >50 ppm, with and without PM loading in the SCRF®, for the inlet temperature range of 200 - 450°C, space velocity in the range of 13 to 48 k/hr and inlet NO2/NOx in the range of 0.2 to 0.5. The NOx reduction in the SCRF® increases to >98 % at ANR 1.2. However, the NH3 slip out of the SCRF® increases significantly at ANR 1.2. xviii The effect of PM loading at 2 and 4 g/L on the NOx reduction performance of the SCRF® was negligible below 300°C. However, with PM loading in the SCRF®, the NOx reduction decreased by 3 - 5% when compared to the clean SCRF®, for inlet temperature >350°C. Experimental data were also collected by reference [1] to investigate the NO2 assisted PM oxidation in the SCRF® for the inlet temperature range of 260 - 370°C, with and without urea injection and thermal oxidation of PM in the SCRF® for the inlet temperature range of 500 - 600°C, without urea injection by reference [1]. The experimental data obtained from this study and [1] will be used to develop and calibrate the SCR-F model at Michigan Tech. The NH3 storage for the production-2013-SCR and the SCRF® (with and without PM loading) were determined from the steady state engine experimental data. The NH3 storage for the production-2013-SCR and the SCRF® (without PM loading) were within ±5 gmol/m3 of the substrate, with maximum NH3 storage of 75 - 80 gmol/m3 of the substrate, at the SCR/SCRF® inlet temperature of 200°C. The NH3 storage in the SCRF®, with 2 g/L PM loading, decreased by 30%, when compared to the NH3 storage in the SCRF®, without PM loading. The further increase in the PM loading in the SCRF®, from 2 to 4 g/L, had negligible effect on NH3 storage.
