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Wei J, He C, Zeng Y. Diesel soot combustion in air-NO environment: Evolution of soot physical properties and fragmentation characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167412. [PMID: 37769740 DOI: 10.1016/j.scitotenv.2023.167412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Since the oxidation activity of nitrogen oxides on soot is obviously higher than that of O2, it is one of the most effective means to improve soot combustion in diesel particulate filter (DPF) by fully utilizing the oxidation activity of nitrogen oxides in diesel exhaust. This paper investigated the physical properties (i.e. morphology, primary particle diameter, fractal dimension and nanostructure) and oxidation-induced fragmentation characteristics of diesel exhaust soot particles during oxidation degrees (0 %, 20 %, 50 % and 80 %) in different atmospheres (air, air-1000 ppm NO and air-2000 ppm NO). The results showed that during the oxidation process the variation trends of soot morphology in air and air-NO environments were similar, while the number and size of primary particles in an aggregate decreased and the fractal dimension of the aggregate increased with the presence of NO in air atmosphere. With the progress of oxidation, the nanostructure of soot particles became more ordered, while this variation trend was slowed down when NO was added to the air atmosphere. This is because soot particles oxidized in air-NO atmospheres showed less probability of internal oxidation but more external oxidation than those in air atmosphere. Over the oxidation process, the soot aggregate fragmentation rate presented a decreasing variation trend under each oxidizing atmosphere, with a higher aggregate fragmentation rate and more apparent variations in air-NO atmospheres. Moreover, in the air atmosphere, the probability of primary soot particle fragmentation showed a consistent upward trend, while the addition of NO slowed down this trend and showed an upward trend in stages 1(0 % ∼ 20 %) and 2(20 % ∼ 50 %), but a downward trend in stage 3(50 % ∼ 80 %). This suggests that the addition of NO reduces the probability of oxidants (especially O2) entering the particles, which would lead to a decrease in the probability of primary soot fragmentation caused by internal oxidation.
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Affiliation(s)
- Jiangjun Wei
- School of Automotive and Transportation Engineering, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Chengjun He
- School of Automotive and Transportation Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
| | - Yang Zeng
- School of Automotive and Transportation Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
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Wu D, Meng Z, Bao Z, Deng M, Ou J, Chen Z. Experimental study on gas and particle emission characteristics of carbon black oxidation process in the presence of water and catalysts. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165748. [PMID: 37495122 DOI: 10.1016/j.scitotenv.2023.165748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/10/2023] [Accepted: 07/21/2023] [Indexed: 07/28/2023]
Abstract
The study of oxidation characteristics of carbon black particle is the basis to investigate the regeneration process and characteristics of diesel particulate filter (DPF). Based on the fixed-bed test bench, the gas and particle emission characteristics of carbon black oxidation process in the presence of water are investigated under different temperatures, Printex-U (PU) masses, and catalysts. The experimental results show that the rise of temperature and PU mass increases the emissions of CO, CO2 and the total average particle number (PN). The oxidation efficiency (η) increases with temperature, but decreases with PU mass. The addition of catalysts promotes PU oxidation, and reduces CO emission. Due to the influence of particle diffusion, CeO2 has slightly lower efficiency than Pt/Al2O3 in the same ratio (1:1), but it is beneficial to significantly reduce particle emission, especially as the ratio increases (1:5). Water decreases CO and the η in PU oxidation, and the negative impact is gradually reduced after 3 % water concentration; However, the PN significantly increases, and expands the particle size range, particularly at high temperature and adding Pt/Al2O3 (from about 10 nm to 6- 30 nm, and a large number of particles with 30- 100 nm are produced). Additionally, the CO2/CO ratio of carbon black oxidation gradually increases with water concentration. Controlling DPF regeneration needs to strike a balance between the benefits on increasing oxidation efficiency and the potential negatives on particulate and harmful gas emission.
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Affiliation(s)
- Daigeng Wu
- Key Laboratory of Fluid and Power Machinery, Ministry of Education (Xihua University), Chengdu 610039, PR China; Vehicle Measurement, Control and Safety Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, PR China
| | - Zhongwei Meng
- Key Laboratory of Fluid and Power Machinery, Ministry of Education (Xihua University), Chengdu 610039, PR China; Vehicle Measurement, Control and Safety Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, PR China.
| | - Zhongqiang Bao
- Key Laboratory of Fluid and Power Machinery, Ministry of Education (Xihua University), Chengdu 610039, PR China; Vehicle Measurement, Control and Safety Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, PR China
| | - Meng Deng
- Key Laboratory of Fluid and Power Machinery, Ministry of Education (Xihua University), Chengdu 610039, PR China; Vehicle Measurement, Control and Safety Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, PR China
| | - Juan Ou
- Power Machinery and Vehicular Engineering Institute, Zhejiang University, Hangzhou 310027, PR China
| | - Zhou Chen
- Key Laboratory of Fluid and Power Machinery, Ministry of Education (Xihua University), Chengdu 610039, PR China; Vehicle Measurement, Control and Safety Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, PR China
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Luo J, Zhang H, Liu Z, Zhang Z, Pan Y, Liang X, Wu S, Xu H, Xu S, Jiang C. A review of regeneration mechanism and methods for reducing soot emissions from diesel particulate filter in diesel engine. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:86556-86597. [PMID: 37421534 DOI: 10.1007/s11356-023-28405-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/19/2023] [Indexed: 07/10/2023]
Abstract
With the global emphasis on environmental protection and the proposal of the climate goal of "carbon neutrality," countries around the world are calling for reductions in carbon dioxide, nitrogen oxide, and particulate matter pollution. These pollutants have severe impacts on human lives and should be effectively controlled. Engine exhaust is the most serious pollution source, and diesel engine is an important contributor to particulate matter. Diesel particulate filter (DPF) technology has proven to be an effective technology for soot control at the present and in the future. Firstly, the exacerbating effect of particulate matter on human infectious disease viruses is discussed. Then, the latest developments in the influence of key factors on DPF performance are reviewed at different observation scales (wall, channel, and entire filter). In addition, current soot catalytic oxidant schemes are presented in the review, and the significance of catalyst activity and soot oxidation kinetic models are highlighted. Finally, the areas that need further research are determined, which has important guiding significance for future research. Current catalytic technologies are focused on stable materials with high mobility of oxidizing substances and low cost. The challenge of DPF optimization design is to accurately calculate the balance between soot and ash load, DPF regeneration control strategy, and exhaust heat management strategy.
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Affiliation(s)
- Jianbin Luo
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, 545006, Liuzhou, China
| | - Haiguo Zhang
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, 545006, Liuzhou, China
| | - Zhonghang Liu
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, 545006, Liuzhou, China
| | - Zhiqing Zhang
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, 545006, Liuzhou, China.
| | - Yajuan Pan
- School of Mechanical Engineering, Liuzhou Institute of Technology, Liuzhou, 545616, China
| | - Xiguang Liang
- Liuzhou Jindongfang Automotive Parts Co., Ltd., Liuzhou, 545036, China
| | - Shizhuo Wu
- Liuzhou Branch, Aisn AUTO R&D Co., Ltd., Liuzhou, 545616, China
| | - Hongxiang Xu
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, 545006, Liuzhou, China
| | - Song Xu
- School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, 545006, Liuzhou, China
| | - Chunmei Jiang
- Institute of the New Energy and Energy-Saving & Emission-Reduction, Guangxi University of Science and Technology, Liuzhou, 545006, China
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Yashnik SA, Ismagilov ZR. Diesel Oxidation Catalyst Pt–Pd/MnOx–Al2O3 for Soot Emission Control: Effect of NO and Water Vapor on Soot Oxidation. Top Catal 2023. [DOI: 10.1007/s11244-022-01779-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Zhong C, Liang J, Zhu Y, Zuo H, Wang S, Chen B, Wu X, Wu C. Effects analysis on soot oxidation performance in the diesel particulate filter based on synergetic passive-active composite regeneration methods. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.118013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Xiong J, Zhang P, Li Y, Wei Y, Zhang Y, Liu J, Zhao Z. Ordered macro-mesoporous nanostructure of Pd/ZrO2 catalyst for boosting catalytic NO-assisted soot oxidation. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116635] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
The energy efficiency of Gasoline Direct Injection (GDI) engines is leading to a continuous increase in GDI engine vehicle population. Consequently, their particulate matter (soot) emissions are also becoming a matter of concern. As required for diesel engines, to meet the limits set by regulations, catalyzed particulate filters are considered as an effective solution through which soot could be trapped and burnt out. However, in contrast to diesel application, the regeneration of gasoline particulate filters (GPF) is critical, as it occurs with almost an absence of NOx and under oxygen deficiency. Therefore, in the recent years it was of scientific interest to develop efficient soot oxidation catalysts that fit such particular gasoline operating conditions. Among them ceria- and perovskite-based formulations are emerging as the most promising materials. This overview summarizes the very recent academic contributions focusing on soot oxidation materials for GDI, in order to point out the most promising directions in this research area.
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Cortés-Reyes M, Herrera C, Larrubia MÁ, Alemany LJ. Understanding of Soot Removal Mechanism over DeNO x-Catalysts as Passive Converters. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c05363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marina Cortés-Reyes
- Departamento de Ingeniería Química, Facultad de Ciencias, Campus de Teatinos, Universidad de Málaga, Málaga E-29071, Spain
| | - Concepción Herrera
- Departamento de Ingeniería Química, Facultad de Ciencias, Campus de Teatinos, Universidad de Málaga, Málaga E-29071, Spain
| | - M. Ángeles Larrubia
- Departamento de Ingeniería Química, Facultad de Ciencias, Campus de Teatinos, Universidad de Málaga, Málaga E-29071, Spain
| | - Luis J. Alemany
- Departamento de Ingeniería Química, Facultad de Ciencias, Campus de Teatinos, Universidad de Málaga, Málaga E-29071, Spain
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Srilomsak M, Hanamura K. Time-lapse visualization of shrinking soot in diesel particulate filter during active-regeneration using field emission scanning electron microscopy. J Microsc 2020; 279:85-97. [PMID: 32415865 DOI: 10.1111/jmi.12905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/06/2020] [Accepted: 05/11/2020] [Indexed: 11/30/2022]
Abstract
Regeneration of diesel particulate filter (DPF) is a complicated process due to its high operating temperature and associated oxidation of soot on the filter substrate. Several oxidation mechanisms of diesel soot have been proposed based on reaction kinetics, but more information about the oxidation phenomena is needed in a practical system, that is, soot oxidation on a DPF substrate. In this work, the DPF regeneration process was, for the first time, visualized at the particle scale ex-situ, in time-lapse series, using field emission scanning electron microscopy (FE-SEM). Time-lapse transformation of soot cake layer on a real DPF was followed from initiation through the complete regeneration process. In parallel, transformation of the soot primary particle diameter was directly measured using high-resolution transmission electron microscopy. FE-SEM visualization clearly showed shrinkage of the soot cake layer on the DPF wall as oxidation progressed. Furthermore, diameter distribution analysis revealed a trend of shrinkage of the nanoscale soot primary particles during oxidation, supporting the FE-SEM observations of the micron-scale shrinkage of the agglomerated soot cake layer. Fragmentation of the shrunken soot cake layer was also observed and is suspected to be a result of locally higher gas flow that depends on surface pore morphology of the filter substrate. LAY DESCRIPTION: In this work, the DPF regeneration process was, for the first time, visualized at the particle scale ex-situ, in time-lapse series, using field emission scanning electron microscopy (FE-SEM). Time-lapse transformation of soot cake layer on a real DPF was followed from initiation through the complete regeneration process. In parallel, transformation of the soot primary particle diameter was directly measured using high resolution transmission electron microscopy. FE-SEM visualization clearly showed shrinkage of the soot cake layer on the DPF wall as oxidation progressed. Furthermore, diameter distribution analysis revealed a trend of shrinkage of the nano-scaled soot primary particles during oxidation, supporting the FE-SEM observations of the shrinkage of the micron-scale agglomerated soot cake layer. Fragmentation of the shrunken soot cake layer was also observed and is suspected to be a result of locally higher gas flow that depends on surface pore morphology of the filter substrate. Further detail mechanism about transformations of the soot cake layer was additionally discussed based on electrostatic attraction.
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Affiliation(s)
- M Srilomsak
- Department of Mechanical Engineering, Graduate School of Engineering, Tokyo Institute of Technology, Meguro, Tokyo, Japan
| | - K Hanamura
- Department of Mechanical Engineering, Graduate School of Engineering, Tokyo Institute of Technology, Meguro, Tokyo, Japan
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Low temperature, medium temperature and high temperature performance of the continuous regenerative diesel particulate filter assisted by electric regeneration. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.07.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Yashnik SA, Ismagilov ZR. Pt–Pd/MnOx–Al2O3 Oxidation Catalysts: Prospects of Application for Control of the Soot Emission with Diesel Exhaust Gases. KINETICS AND CATALYSIS 2019. [DOI: 10.1134/s0023158419040207] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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