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Shao M, Zhang C, Chen Q, Wu H, Dong Z, Bai X, Wang N, Xu Q. Hydrothermal-enhanced pyrolysis for efficient NO X reduction and biochar valorization from food waste digestate. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 183:112-122. [PMID: 38739988 DOI: 10.1016/j.wasman.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 04/26/2024] [Accepted: 05/08/2024] [Indexed: 05/16/2024]
Abstract
Pyrolysis has emerged as a promising technology for valorizing digestate resulting from the anaerobic digestion of food waste. However, the high NOX emissions during pyrolysis limit its application. This study proposed a hydrothermal coupled pyrolysis process to control the element transfer in digestate during biochar production. The efficient reduction of NOX emissions and the improvement of biochar adsorbability were realized. The hydrothermal process reduced the nitrogen content in solid digestate by 49.10 %-81.79 %, thus reducing the NOX precursors in syngas and the N-containing substances in bio-oil. Additionally, the specific surface area and the total pore volume of biochar were enhanced from 25 m2/g to 60-73 m2/g and 0.06 cm3/g to 0.12-0.14 cm3/g, respectively. More defects, oxygen-containing functional groups, and doped Ca on the biochar resulted in a high phosphate removal efficiency of 94 %. The proposed technology provides an efficient and environmentally friendly way to utilize the digestate.
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Affiliation(s)
- Mingshuai Shao
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China
| | - Chao Zhang
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China
| | - Qindong Chen
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China
| | - Huanan Wu
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China
| | - Zihang Dong
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China
| | - Xinyue Bai
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China
| | - Ning Wang
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China
| | - Qiyong Xu
- Shenzhen Engineering Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Nanshan District, Shenzhen, 518055, PR China.
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Guo S, Wang Y, Zhu S, Qu H, Zhao D, Li X, Zhao Y. Reactive Force Field Molecular Dynamics Investigation of NH 3 Generation Mechanism during Protein Pyrolysis Process. Molecules 2024; 29:2016. [PMID: 38731506 PMCID: PMC11085164 DOI: 10.3390/molecules29092016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
The mechanism of ammonia formation during the pyrolysis of proteins in biomass is currently unclear. To further investigate this issue, this study employed the AMS 2023.104 software to select proteins (actual proteins) as the model compounds and the amino acids contained within them (assembled amino acids) as the comparative models. ReaxFF molecular dynamics simulations were conducted to explore the nitrogen transformation and NH3 generation mechanisms in three-phase products (char, tar, and gas) during protein pyrolysis. The research results revealed several key findings. Regardless of whether the model compounds are actual proteins or assembled amino acids, NH3 is the primary nitrogen-containing product during pyrolysis. However, as the temperature rises to higher levels, such as 2000 K and 2500 K, the amount of NH3 decreases significantly in the later stages of pyrolysis, indicating that it is being converted into other nitrogen-bearing species, such as HCN and N2. Simultaneously, we also observed significant differences between the pyrolysis processes of actual proteins and assembled amino acids. Notably, at 2000 K, the amount of NH3 generated from the pyrolysis of assembled amino acids was twice that of actual proteins. This discrepancy mainly stems from the inherent structural differences between proteins and amino acids. In proteins, nitrogen is predominantly present in a network-like structure (NH-N), which shields it from direct external exposure, thus requiring more energy for nitrogen to participate in pyrolysis reactions, making it more difficult for NH3 to form. Conversely, assembled amino acids can release NH3 through a simpler deamination process, leading to a significant increase in NH3 production during their pyrolysis.
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Affiliation(s)
- Shuai Guo
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin 132012, China; (S.G.); (Y.W.); (H.Q.); (X.L.)
- Shanxi Key Laboratory of Coal Flexible Combustion and Thermal Conversion, Datong 037000, China;
| | - Yu Wang
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin 132012, China; (S.G.); (Y.W.); (H.Q.); (X.L.)
| | - Shujun Zhu
- Shanxi Key Laboratory of Coal Flexible Combustion and Thermal Conversion, Datong 037000, China;
| | - Hongwei Qu
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin 132012, China; (S.G.); (Y.W.); (H.Q.); (X.L.)
| | - Deng Zhao
- College of Vehicles and Energy, Yanshan University, Qinhuangdao 066000, China
| | - Xingcan Li
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin 132012, China; (S.G.); (Y.W.); (H.Q.); (X.L.)
| | - Yan Zhao
- Shenyang Academy of Environmental Sciences, Shenyang 110167, China
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Valorization of Residues from Energy Conversion of Biomass for Advanced and Sustainable Material Applications. SUSTAINABILITY 2022. [DOI: 10.3390/su14094939] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The reduction in greenhouse gas (GHG) emissions by shifting towards renewable energy sources to control global warming is one of the main challenges of the 21st century [...]
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