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Han H, Li A, Zhu M, Hu S, Xu J, Xiong Z, Ren Q, Wang Y, Jiang L, Su S, Xiang J. Heavy tar evolution characteristics during advanced sludge pyrolysis and biomass gasification integrated process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 853:158107. [PMID: 36055490 DOI: 10.1016/j.scitotenv.2022.158107] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/13/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
Sludge pyrolysis and biomass gasification integrated process (SPBG) is an attractive route for the comprehensive utilization of the two materials but more tar is produced in this process compared to traditional biomass steam gasification. Nitrogen-containing compounds in the tar bring threatens to the environment and heavy components in the tar contributes to undesired coke formation. In current study, the evolution of heavy tar, especially the nitrogen-rich components, during SPBG is revealed for the first time. It was found that heavy components were mainly distributed in the mass range of 150-450 Da, where aromatics consisted of carbon, hydrogen and nitrogen atoms were the most abundant. Deamination (NH3) and the combination of quinoline accompanied with the generation of the heavy components. Organics from sludge could react with biomass to form heavier oxygen-containing molecules. Meanwhile, steam from sludge promoted heavy components to crack by tar reforming reactions and consumed radicals in bio-char to inhibit the catalytic cracking of tar. Under the combination of above reactions, more heavy molecules were generated at low sludge volatile/biomass ratio and the aromatic content in the heavy tar decreased at high sludge volatile/biomass ratio.
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Affiliation(s)
- Hengda Han
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Aishu Li
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Meng Zhu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Song Hu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Jun Xu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhe Xiong
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qiangqiang Ren
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yi Wang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Long Jiang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Sheng Su
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jun Xiang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, China
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Abstract
The catalyst MNi0.9Zr0.1O3 (M = La, Ce, and Cs) was prepared using the sol–gel preparation technique investigated for the dry reforming of methane reaction to examine activity, stability, and H2/CO ratio. The lanthanum in the catalyst LaNi0.9Zr0.1O3 was partially substituted for cerium and zirconium for yttrium to give La0.6Ce0.4Ni0.9Zr0.1−xYxO3 (x = 0.05, 0.07, and 0.09). The La0.6Ce0.4Ni0.9Zr0.1−xYxO3 catalyst’s activity increases with an increase in yttrium loading. The activities of the yttrium-modified catalysts La0.6Ce0.4Ni0.9Zr0.03Y0.07O3 and La0.6Ce0.4Ni0.9Zr0.01Y0.09O3 are higher than the unmodified La0.6Ce0.4Ni0.9Zr0.1O3 catalyst, the latter having methane and carbon dioxide conversion values of 84% and 87%, respectively, and the former with methane and carbon dioxide conversion values of 86% and 90% for La0.6Ce0.4Ni0.9Zr0.03Y0.07O3 and 89% and 91% for La0.6Ce0.4Ni0.9Zr0.01Y0.09O3, respectively. The BET analysis depicted a low surface area of samples ranging from 2 to 9 m2/g. The XRD peaks confirmed the formation of a monoclinic phase of zirconium. The TPR showed that apparent reduction peaks occurred in moderate temperature regions. The TGA curve showed weight loss steps in the range 773 K–973 K, with CsNi0.9Zr0.1O3 carbon deposition being the most severe. The coke deposit on La0.6Ce0.4Ni0.9Zr0.1O3 after 7 h time on stream (TOS) was the lowest, with 20% weight loss. The amount of weight loss increases with a decrease in zirconium loading.
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