Influence of thermal ageing on oxidation performance and nanostructures of dry soot in diesel engine

Abstract

Diesel soot subjected to high exhaust temperature suffers from thermal ageing, which is difficult to be removed by regeneration process. Based on the thermogravimetric (TG) analysis and images by high resolution transmission electron microscope (HRTEM), effects of thermal ageing temperature, ageing time and oxygen concentration on oxidation characteristic of soot are investigated. The activation energy of soot increases with the increase of ageing temperature and oxygen concentration. The activation energy increases rapidly when the ageing time is less than 45 min, and then it keeps in a value of 157 kJ/mol when the ageing time is between 45 and 60 min. Compared to the soot without thermal ageing, the shape of ageing soot particles presents shorter diameter and more regular circle by observing soot nanostructure. With the increase of ageing temperature, ageing time and oxygen concentration, the more stable structure of “shell and core” is shown in the basic carbon. The soot has an increased fringe length, decreased tortuosity and separation distance after thermal ageing process, which leads to the deepening of the disorder degree of soot nanostructures and reduction of soot oxidation activity. Consequently, the thermal ageing process should be avoided in order to optimize the active regeneration strategy.

Keywords

thermal ageing / oxidation performance / soot nanostructure / activation energy

References

[1] ChuH-Q, XiangL-K, NieX-K, YaY-C, GuM-Y, EJ-Q. Laminar burning velocity and pollutant emissions of the gasoline components and its surrogate fuels: A review [J]. Fuel, 2020, 269: 117451

[2] HanW-W, ZhouY, ZhuT, ChuH-Q. Combustion synthesis of defect-rich carbon nanotubes as anodes for sodium-ion batteries [J]. Applied Surface Science, 2020, 520146317

[3] LiY-X, NingZ, YanJ-H, LeeT H, LeeC F. Experimental investigation on combustion and unregulated emission characteristics of butanol-isomer/gasoline blends [J]. Journal of Central South University, 2019, 26(8): 2244-2258

[4] ZhangG-J, EJ-Q, ZuoQ-S, GongJ-K, ZuoW, YuanW-H. Numerical simulation on trapping efficiency of steady filtration process in diesel particulate filter and its experimental verification [J]. Journal of Central South University, 2015, 22(11): 4456-4466

[5] ZhangQ, FangJ, MengZ-W, ChenC, QinZ-H. Thermogravimetric analysis of soot combustion in the presence of ash and soluble organic fraction [J]. RSC Advances, 2020, 10(55): 33436-33443

[6] MengZ-W, ChenC, LiJ-S, FangJ, TanJ, QinY, JiangY, QinZ-H, BaiW-L, LiangK. Particle emission characteristics of DPF regeneration from DPF regeneration bench and diesel engine bench measurements [J]. Fuel, 2020, 262116589

[7] WangF-F, ZhangE-S, XuX-H, WangJ-B, MiJ-C. Particle deposition in ventilation duct with convex or concave wall cavity [J]. Journal of Central South University, 2018, 25(11): 2601-2614

[8] ShiY-X, CaiY-X, LiX-H, JiL, ChenY, WangW-K. Evolution of diesel particulate physicochemical properties using nonthermal plasma [J]. Fuel, 2019, 2531292-1299

[9] FangJ, MengZ-W, LiJ-S, DuY-H, QinY, JiangY, BaiW-L, ChaseG G. The effect of operating parameters on regeneration characteristics and particulate emission characteristics of diesel particulate filters [J]. Applied Thermal Engineering, 2019, 148: 860-867

[10] DuY-H, MengZ-W, FangJ, QinY, JiangY, LiS, LiJ-S, ChenC, BaiW-L. Characterization of soot deposition and oxidation process on catalytic diesel particulate filter with ash loading through an optimized visualized method [J]. Fuel, 2019, 243: 251-261

[11] BuonoD, SenatoreA, PratiM V. Particulate filter behaviour of a diesel engine fueled with biodiesel [J]. Applied Thermal Engineering, 2012, 49: 147-153

[12] ShiY-X, CaiY-X, FanR-L, CuiY-X, ChenY, JiL. Characterization of soot inside a diesel particulate filter during a nonthermal plasma promoted regeneration step [J]. Applied Thermal Engineering, 2019, 150: 612-619

[13] ROSSOMANDO B, ARSIE I, MELONI E, PALMA V, PIANESE C. Experimental testing of a low temperature regenerating catalytic DPF at the exhaust of a light-duty diesel engine [C]// WCX World Congress Experience, 2018-01-0351. DOI: https://doi.org/10.4271/2018-01-0351.

[14] MengZ-W, LiJ-S, FangJ, TanJ, QinY, JiangY, QinZ-H, BaiW-L, LiangK. Experimental study on regeneration performance and particle emission characteristics of DPF with different inlet transition sections lengths [J]. Fuel, 2020, 262: 116487

[15] FangJ, QinZ-H, MengZ-W, JiangY, LiuJ, ZhangQ, TanJ. Performance of diesel soot oxidation in the presence of ash species [J]. Energy & Fuels, 2020, 34(2): 2185-2192

[16] FangJ, MengZ-W, LiJ, PuY-F, DuY-H, LiJ-S, JinZ-X, ChenC, ChaseG G. The influence of ash on soot deposition and regeneration processes in diesel particular filter [J]. Applied Thermal Engineering, 2017, 124633-640

[17] FangJ, ZhangQ, MengZ-W, LuoY, OuJ, DuY-H, ZhangZ-L. Effects of ash composition and ash stack heights on soot deposition and oxidation processes in catalytic diesel particulate filter [J]. Journal of the Energy Institute, 2020, 93: 1942-1950

[18] LiuJ-H, WangL-J, SunP, WangP, LiY-Q, MaH-J, WuP-C, LiuZ-G. Effects of iron-based fuel borne catalyst addition on microstructure, element composition and oxidation activity of diesel exhaust particles [J]. Fuel, 2020, 270: 117597

[19] EJ-Q, ZhaoX-H, XieL-F, ZhangB, ChenJ-W, ZuoQ-S, HanD-D, HuW-Y, ZhangZ-Q. Performance enhancement of microwave assisted regeneration in a wall-flow diesel particulate filter based on field synergy theory [J]. Energy, 2019, 169719-729

[20] PalmaV, MeloniE. Microwave assisted regeneration of a catalytic diesel soot trap [J]. Fuel, 2016, 181: 421-429

[21] FangJ, ShiR, MengZ-W, JiangY, QinZ-H, ZhangQ, QinY, TanJ, BaiW-L. The interaction effect of catalyst and ash on diesel soot oxidation by thermogravimetric analysis [J]. Fuel, 2019, 258: 116151

[22] LiatiA, EggenschwilerP D, SchreiberD, ZelenayV, AmmannM. Variations in diesel soot reactivity along the exhaust after-treatment system, based on the morphology and nanostructure of primary soot particles [J]. Combustion and Flame, 2013, 160(3): 671-681

[23] ROSSOMANDO B, ARSIE I, MELONI E, PALMA V, PIANESE C. Experimental test on the feasibility of passive regeneration in a catalytic dpf at the exhaust of a light-duty diesel engine [C]// 14th International Conference on Engines & Vehicles, 2019-24-0045. DOI: https://doi.org/10.4271/2019-24-0045.

[24] EJ-Q, ZuoW, GaoJ-X, PengQ-G, ZhangZ-Q, HieuP M. Effect analysis on pressure drop of the continuous regeneration-diesel particulate filter based on NO₂ assisted regeneration [J]. Applied Thermal Engineering, 2016, 100356-366

[25] MeloniE, PalmaV, VaianoV. Optimized microwave susceptible catalytic diesel soot trap [J]. Fuel, 2017, 205: 142-152

[26] GaddamC K, WalR V, ChenX, YezeretsA, KamasamudramK. Reconciliation of carbon oxidation rates and activation energies based on changing nanostructure [J]. Carbon, 2016, 98: 545-556

[27] MengZ-W, YangD, YanY. Study of carbon black oxidation behavior under different heating rates [J]. Journal of Thermal Analysis and Calorimetry, 2014, 118(1): 551-559

[28] DengY-W, CuiJ-H, EJ-Q, ZhangB, ZhaoX-H, ZhangZ-Q, HanD-D. Investigations on the temperature distribution of the diesel particulate filter in the thermal regeneration process and its field synergy analysis [J]. Applied Thermal Engineering, 2017, 123: 92-102

[29] BredinA, LarcherA V, MullinsB J. Thermogravimetric analysis of carbon black and engine soot—Towards a more robust oil analysis method [J]. Tribology International, 2011, 44(12): 1642-1650

[30] YehliuK, WalR V, ArmasO, BoehmanA L. Impact of fuel formulation on the nanostructure and reactivity of diesel soot [J]. Combustion and Flame, 2012, 159(12): 3597-3606

[31] RajA, YangS Y, ChaD, TayouoR, ChungS H. Structural effects on the oxidation of soot particles by O2: Experimental and theoretical study [J]. Combustion and Flame, 2013, 160(9): 1812-1826

[32] JaramilloI C, GaddamC K, WalR V, HuangC H, LevinthalJ D, LightyJ S. Soot oxidation kinetics under pressurized conditions [J]. Combustion and Flame, 2014, 161(11): 2951-2965

[33] OschatzM, PréP, DörflerS, NickelW, BeaunierP, RouzaudJ-N, FischerC, BrunnerE, KaskelS. Nanostructure characterization of carbide-derived carbons by morphological analysis of transmission electron microscopy images combined with physisorption and Raman spectroscopy [J]. Carbon, 2016, 105: 314-322

[34] WangX-B, LiS-S, AdeosunA, LiY, VujanovićM, TanH-Z, DuićN. Effect of potassium-doping and oxygen concentration on soot oxidation in O₂/CO₂ atmosphere: A kinetics study by thermogravimetric analysis [J]. Energy Conversion and Management, 2017, 149: 686-697

[35] ChongH S, AggarwalS K, LeeK O, YangS Y, SeongH. Experimental investigation on the oxidation characteristics of diesel particulates relevant to DPF regeneration [J]. Combustion Science and Technology, 2013, 185(1): 95-121

[36] YehliuK, WalR V, BoehmanA L. Development of an HRTEM image analysis method to quantify carbon nanostructure [J]. Combustion and Flame, 2011, 158(9): 1837-1851

[37] YehliuK, WalR V, BoehmanA L. A comparison of soot nanostructure obtained using two high resolution transmission electron microscopy image analysis algorithms [J]. Carbon, 2011, 49(13): 4256-4268

[38] WalR V, TomasekA J, StreetK, HullD R, ThompsonW K. Carbon nanostructure examined by lattice fringe analysis of high-resolution transmission electron microscopy images [J]. Applied Spectroscopy, 2004, 58(2): 230-237

[39] WalR V, TomasekA J. Soot oxidation [J]. Combustion and Flame, 2003, 134(12): 1-9

[40] WalR V, YezeretsA, CurrierN W, KimD H, WangC M. HRTEM Study of diesel soot collected from diesel particulate filters [J]. Carbon, 2007, 45(1): 70-77

[41] WangC-A, HuddleT, HuangC H, ZhuW, WalR V, LesterE H, MathewsJ P. Improved quantification of curvature in high-resolution transmission electron microscopy lattice fringe micrographs of soots [J]. Carbon, 2017, 117: 174-181

[42] ChengH K F, ChongM F, LiuE, ZhouK, LiL. Thermal decomposition kinetics of multiwalled carbon nanotube/polypropylene nanocomposites [J]. Journal of Thermal Analysis and Calorimetry, 2014, 117(1): 63-71

[43] KholghyM R, VeshkiniA, ThomsonM J. The core-shell internal nanostructure of soot-A criterion to model soot maturity [J]. Carbon, 2016, 100: 508-536

[44] TanP-Q, LiY, ShenH-Y. Effect of lubricant sulfur on the morphology and elemental composition of diesel exhaust particles [J]. Jounal of Environmental Sciences, 2017, 55: 354-362

[45] KameyaY, HayashiT, MotosukeM. Oxidation-resistant graphitic surface nanostructure of carbon black developed by ethanol thermal decomposition [J]. Diamond and Related Materials, 2016, 65: 26-31