Evaluation of hydrothermal carbonization as a preliminary step for the production of functional materials from biogas digestate

Catalina Rodriguez Correa, Maria Bernardo, Rui P. P. L. Ribeiro, Isabel A. A. C. Esteves, Andrea Kruse

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18 Citations (Scopus)

Abstract

Digestate from a biogas plant that uses solely biomass for biogas production was used as precursor material for the production of activated carbon as an alternative to increase its added value. The digestate was converted into hydrochar by hydrothermal carbonization varying the temperature (190–250 °C), residence time (3 and 6 h), and pH (5 and 7). Temperature followed by residence time had the strongest influence on the chemical composition and thermal stability of the hydrochars. A significant effect of the pH was not observed. The hydrochars were chemically activated to enhance the surface area and use them as activated carbon. As a consequence, the surface areas increased from 8 to 14 m2/g (hydrochars) to 930–1351 m2/g (activated carbons). Furthermore, large micropore volumes were measured (0.35–0.50 cm3/g). The activated carbons were studied as adsorbents in gas phase applications, showing that the product of digestate is a very effective adsorbent for carbon dioxide (CO2). Especially the activated carbon obtained from the hydrochar produced at 250 °C for 6 h, which adsorbed 8.80 mol CO2/kg at 30 °C and 14.8 bar. Additionally, the activated carbons showed a stronger affinity towards CO2 compared to methane (CH4), which makes this material suitable for the upgrading of raw biogas to biomethane.

Original languageEnglish
Pages (from-to)461-474
Number of pages14
JournalJournal of Analytical and Applied Pyrolysis
Volume124
DOIs
Publication statusPublished - 1 Mar 2017

Fingerprint

Functional materials
Biofuels
Biogas
Carbonization
Activated carbon
Adsorbents
Methane
Carbon Dioxide
Carbon dioxide
Biomass
Thermodynamic stability
Gases
Temperature
Chemical analysis

Keywords

  • Biogas
  • Carbon adsorbent materials
  • Digestate
  • Gas separation by adsorption
  • Hydrothermal carbonization

Cite this

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title = "Evaluation of hydrothermal carbonization as a preliminary step for the production of functional materials from biogas digestate",
abstract = "Digestate from a biogas plant that uses solely biomass for biogas production was used as precursor material for the production of activated carbon as an alternative to increase its added value. The digestate was converted into hydrochar by hydrothermal carbonization varying the temperature (190–250 °C), residence time (3 and 6 h), and pH (5 and 7). Temperature followed by residence time had the strongest influence on the chemical composition and thermal stability of the hydrochars. A significant effect of the pH was not observed. The hydrochars were chemically activated to enhance the surface area and use them as activated carbon. As a consequence, the surface areas increased from 8 to 14 m2/g (hydrochars) to 930–1351 m2/g (activated carbons). Furthermore, large micropore volumes were measured (0.35–0.50 cm3/g). The activated carbons were studied as adsorbents in gas phase applications, showing that the product of digestate is a very effective adsorbent for carbon dioxide (CO2). Especially the activated carbon obtained from the hydrochar produced at 250 °C for 6 h, which adsorbed 8.80 mol CO2/kg at 30 °C and 14.8 bar. Additionally, the activated carbons showed a stronger affinity towards CO2 compared to methane (CH4), which makes this material suitable for the upgrading of raw biogas to biomethane.",
keywords = "Biogas, Carbon adsorbent materials, Digestate, Gas separation by adsorption, Hydrothermal carbonization",
author = "{Rodriguez Correa}, Catalina and Maria Bernardo and Ribeiro, {Rui P. P. L.} and Esteves, {Isabel A. A. C.} and Andrea Kruse",
note = "This work was financed by the ERANet LAC initiative (ELAC2014/BEE-0367). Additionally, it was partially supported by the Associate Laboratory Research Unit for Green Chemistry, Technologies and Processes Clean, LAQV which is financed by national funds from FCT/MCTES (UID/QUI/50006/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007265). The authors of this work would like to thank the Bauer family for providing the digestate. Additionally, special thanks go to K. Suwelack and P. Fleischman for providing the fiber analysis, B. Rolli for conducting the GC-MS measurements of the HTC process waters, Dr. T. Otto and D. Neumann-Walther for measuring the N<INF>2</INF> isotherms, Dr. C. Fischer (Netzsch GmbH) for the mass spectrometer results, H. Oliphant for spell checking the article, and Andre Portela for his collaboration in the gas adsorption measurements. Isabel A. A. C. Esteves, Rui P. P. L. Ribeiro and Maria Bernardo acknowledge FCT/MCTES for financial support through FCT Investigator Contract IF/01016/2014 and grants SFRH/BPD/103533/2014 and SFRH/BPD/93407/2013, respectively.",
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TY - JOUR

T1 - Evaluation of hydrothermal carbonization as a preliminary step for the production of functional materials from biogas digestate

AU - Rodriguez Correa, Catalina

AU - Bernardo, Maria

AU - Ribeiro, Rui P. P. L.

AU - Esteves, Isabel A. A. C.

AU - Kruse, Andrea

N1 - This work was financed by the ERANet LAC initiative (ELAC2014/BEE-0367). Additionally, it was partially supported by the Associate Laboratory Research Unit for Green Chemistry, Technologies and Processes Clean, LAQV which is financed by national funds from FCT/MCTES (UID/QUI/50006/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007265). The authors of this work would like to thank the Bauer family for providing the digestate. Additionally, special thanks go to K. Suwelack and P. Fleischman for providing the fiber analysis, B. Rolli for conducting the GC-MS measurements of the HTC process waters, Dr. T. Otto and D. Neumann-Walther for measuring the N<INF>2</INF> isotherms, Dr. C. Fischer (Netzsch GmbH) for the mass spectrometer results, H. Oliphant for spell checking the article, and Andre Portela for his collaboration in the gas adsorption measurements. Isabel A. A. C. Esteves, Rui P. P. L. Ribeiro and Maria Bernardo acknowledge FCT/MCTES for financial support through FCT Investigator Contract IF/01016/2014 and grants SFRH/BPD/103533/2014 and SFRH/BPD/93407/2013, respectively.

PY - 2017/3/1

Y1 - 2017/3/1

N2 - Digestate from a biogas plant that uses solely biomass for biogas production was used as precursor material for the production of activated carbon as an alternative to increase its added value. The digestate was converted into hydrochar by hydrothermal carbonization varying the temperature (190–250 °C), residence time (3 and 6 h), and pH (5 and 7). Temperature followed by residence time had the strongest influence on the chemical composition and thermal stability of the hydrochars. A significant effect of the pH was not observed. The hydrochars were chemically activated to enhance the surface area and use them as activated carbon. As a consequence, the surface areas increased from 8 to 14 m2/g (hydrochars) to 930–1351 m2/g (activated carbons). Furthermore, large micropore volumes were measured (0.35–0.50 cm3/g). The activated carbons were studied as adsorbents in gas phase applications, showing that the product of digestate is a very effective adsorbent for carbon dioxide (CO2). Especially the activated carbon obtained from the hydrochar produced at 250 °C for 6 h, which adsorbed 8.80 mol CO2/kg at 30 °C and 14.8 bar. Additionally, the activated carbons showed a stronger affinity towards CO2 compared to methane (CH4), which makes this material suitable for the upgrading of raw biogas to biomethane.

AB - Digestate from a biogas plant that uses solely biomass for biogas production was used as precursor material for the production of activated carbon as an alternative to increase its added value. The digestate was converted into hydrochar by hydrothermal carbonization varying the temperature (190–250 °C), residence time (3 and 6 h), and pH (5 and 7). Temperature followed by residence time had the strongest influence on the chemical composition and thermal stability of the hydrochars. A significant effect of the pH was not observed. The hydrochars were chemically activated to enhance the surface area and use them as activated carbon. As a consequence, the surface areas increased from 8 to 14 m2/g (hydrochars) to 930–1351 m2/g (activated carbons). Furthermore, large micropore volumes were measured (0.35–0.50 cm3/g). The activated carbons were studied as adsorbents in gas phase applications, showing that the product of digestate is a very effective adsorbent for carbon dioxide (CO2). Especially the activated carbon obtained from the hydrochar produced at 250 °C for 6 h, which adsorbed 8.80 mol CO2/kg at 30 °C and 14.8 bar. Additionally, the activated carbons showed a stronger affinity towards CO2 compared to methane (CH4), which makes this material suitable for the upgrading of raw biogas to biomethane.

KW - Biogas

KW - Carbon adsorbent materials

KW - Digestate

KW - Gas separation by adsorption

KW - Hydrothermal carbonization

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DO - 10.1016/j.jaap.2017.02.014

M3 - Article

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JO - Journal of Analytical and Applied Pyrolysis

JF - Journal of Analytical and Applied Pyrolysis

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