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Title: Characterization of biochar prepared from biogas digestate

Abstract

Highlights: • Solid digestate (SD) is a potential feedstock for preparing biochars. • The optimal BET surface area of resulting biochar from SD is over 100 m{sup 2}/g. • The higher temperature leads to the increase in true density of resulting biochar, but exhibited a decreased higher heating value. • The SD-based biochar may be used as a biofertilizer due to the mesoporosity and the abundant in nutrient minerals. - Abstract: In the study, the biogas digestate was evaluated as a potential feedstock for preparing biochars at a broad temperature range of 300–900 °C. The physico-chemical and pore properties of the resulting biochars (denoted as SDBC, solid digestate biochar), including calorific value (higher heating value), surface area/pore volume/pore size distribution, true density, scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray powder diffraction (XRD), were studied. It was found that the higher heating values of the SDBC products were on a decreasing trend as pyrolysis temperature increased, but they indicated an increase in true density. The results are probably associated with the active pyrolysis of the lignocellulosic fragments and the calcination (or shrinkage) processes, thus resulting in the increased contents of aromatic carbon clusters and main mineral constituentsmore » remained. Based on the pore properties, pyrolysis temperature at around 800 °C seemed to be the optimal condition for producing SDBC, where its Brunauer-Emmet-Teller (BET) surface area (>100 m{sup 2}/g) largely increased as compared to that of the digestate feedstock (<1 m{sup 2}/g). Furthermore, the main compositions of mineral ash in the resulting biochar could exist as phosphates, carbonates, or oxides of calcium and other alkali/alkaline earth elements. According to the data on EDS and XRD, more pores could be significantly generated under severe pyrolysis (>700 °C) due to the high aromaticity via the thermal decomposition of lignocelluloses and the volatilization of inorganic minerals.« less

Authors:
 [1];  [2];  [1];  [3];  [2]
  1. Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Pingtung 912, Taiwan (China)
  2. Graduate Institute of Bioresources, National Pingtung University of Science and Technology, Pingtung 912, Taiwan (China)
  3. Department of Biomechatronics Engineering, National Pingtung University of Science and Technology, Pingtung 912, Taiwan (China)
Publication Date:
OSTI Identifier:
22742108
Resource Type:
Journal Article
Journal Name:
Waste Management
Additional Journal Information:
Journal Volume: 66; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0956-053X
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANAEROBIC DIGESTION; BIODEGRADATION; CALORIFIC VALUE; HEATING; SCANNING ELECTRON MICROSCOPY; SOLIDS; SURFACE AREA; TEMPERATURE RANGE 0400-1000 K; WASTE WATER; WATER TREATMENT; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY

Citation Formats

Hung, Chao-Yi, Tsai, Wen-Tien, Chen, Jie-Wei, Lin, Yu-Quan, and Chang, Yuan-Ming. Characterization of biochar prepared from biogas digestate. United States: N. p., 2017. Web. doi:10.1016/J.WASMAN.2017.04.034.
Hung, Chao-Yi, Tsai, Wen-Tien, Chen, Jie-Wei, Lin, Yu-Quan, & Chang, Yuan-Ming. Characterization of biochar prepared from biogas digestate. United States. doi:10.1016/J.WASMAN.2017.04.034.
Hung, Chao-Yi, Tsai, Wen-Tien, Chen, Jie-Wei, Lin, Yu-Quan, and Chang, Yuan-Ming. Tue . "Characterization of biochar prepared from biogas digestate". United States. doi:10.1016/J.WASMAN.2017.04.034.
@article{osti_22742108,
title = {Characterization of biochar prepared from biogas digestate},
author = {Hung, Chao-Yi and Tsai, Wen-Tien and Chen, Jie-Wei and Lin, Yu-Quan and Chang, Yuan-Ming},
abstractNote = {Highlights: • Solid digestate (SD) is a potential feedstock for preparing biochars. • The optimal BET surface area of resulting biochar from SD is over 100 m{sup 2}/g. • The higher temperature leads to the increase in true density of resulting biochar, but exhibited a decreased higher heating value. • The SD-based biochar may be used as a biofertilizer due to the mesoporosity and the abundant in nutrient minerals. - Abstract: In the study, the biogas digestate was evaluated as a potential feedstock for preparing biochars at a broad temperature range of 300–900 °C. The physico-chemical and pore properties of the resulting biochars (denoted as SDBC, solid digestate biochar), including calorific value (higher heating value), surface area/pore volume/pore size distribution, true density, scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray powder diffraction (XRD), were studied. It was found that the higher heating values of the SDBC products were on a decreasing trend as pyrolysis temperature increased, but they indicated an increase in true density. The results are probably associated with the active pyrolysis of the lignocellulosic fragments and the calcination (or shrinkage) processes, thus resulting in the increased contents of aromatic carbon clusters and main mineral constituents remained. Based on the pore properties, pyrolysis temperature at around 800 °C seemed to be the optimal condition for producing SDBC, where its Brunauer-Emmet-Teller (BET) surface area (>100 m{sup 2}/g) largely increased as compared to that of the digestate feedstock (<1 m{sup 2}/g). Furthermore, the main compositions of mineral ash in the resulting biochar could exist as phosphates, carbonates, or oxides of calcium and other alkali/alkaline earth elements. According to the data on EDS and XRD, more pores could be significantly generated under severe pyrolysis (>700 °C) due to the high aromaticity via the thermal decomposition of lignocelluloses and the volatilization of inorganic minerals.},
doi = {10.1016/J.WASMAN.2017.04.034},
journal = {Waste Management},
issn = {0956-053X},
number = ,
volume = 66,
place = {United States},
year = {2017},
month = {8}
}