Revealing roles of CO₂ and N₂ in pressurized hydrothermal carbonization process for enhancing energy recovery and carbon sequestration

TY - JOUR

T1 - Revealing roles of CO2 and N2 in pressurized hydrothermal carbonization process for enhancing energy recovery and carbon sequestration

AU - He, Mingjing

AU - Cao, Yang

AU - Fan, Yinzheng

AU - Mašek, Ondřej

AU - Clark, James H.

AU - Tsang, Daniel C.W.

N1 - Funding Information: The authors appreciate the financial support from the Hong Kong Research Grants Council (PolyU 15231522) and Environment and Conservation Fund (Project 101/2020) for this study. The authors also acknowledge the valuable suggestions from Dr. Iris K.M. Yu at the National University of Singapore. Funding Information: The authors appreciate the financial support from the Hong Kong Research Grants Council (PolyU 15231522) and Environment and Conservation Fund (Project 101/2020) for this study. The authors also acknowledge the valuable suggestions from Dr. Iris K.M. Yu at the National University of Singapore. Publisher Copyright: © 2023 Elsevier Ltd

PY - 2023/10

Y1 - 2023/10

N2 - In this study, CO2– and N2-pressurized hydrothermal carbonization processes were investigated to understand the catalytic effects of CO2 on hydrochar production and its quality (e.g., surface properties, energy recovery, and combustion behaviour). Both CO2– and N2-pressurized HTC processes could enhance the energy recovery (from 61.5% to 63.0–67.8%) in hydrochar by enhancing the dehydration reactions. Nonetheless, the two systems exhibited contrasting trends in volatile release, oxygen removal, and combustion performance as a function of increasing pressure. High N2 pressure enhanced deoxygenation reaction, facilitating the release of volatiles and increasing the hydrochar aromaticity and combustion activation energy (172.7 kJ/mol for HC/5N). Without the contribution of CO2, excessively high pressure may cause an adverse impact on the fuel performance owing to higher oxidation resistance. This study presents an important and feasible strategy to utilise CO2-rich flue gas in the HTC process to produce high-quality hydrochar for renewable energy and carbon recovery.

AB - In this study, CO2– and N2-pressurized hydrothermal carbonization processes were investigated to understand the catalytic effects of CO2 on hydrochar production and its quality (e.g., surface properties, energy recovery, and combustion behaviour). Both CO2– and N2-pressurized HTC processes could enhance the energy recovery (from 61.5% to 63.0–67.8%) in hydrochar by enhancing the dehydration reactions. Nonetheless, the two systems exhibited contrasting trends in volatile release, oxygen removal, and combustion performance as a function of increasing pressure. High N2 pressure enhanced deoxygenation reaction, facilitating the release of volatiles and increasing the hydrochar aromaticity and combustion activation energy (172.7 kJ/mol for HC/5N). Without the contribution of CO2, excessively high pressure may cause an adverse impact on the fuel performance owing to higher oxidation resistance. This study presents an important and feasible strategy to utilise CO2-rich flue gas in the HTC process to produce high-quality hydrochar for renewable energy and carbon recovery.

KW - Bio-renewable energy

KW - Biochar/hydrochar

KW - CO utilisation

KW - Combustion performance

KW - Energy and carbon balance

UR - http://www.scopus.com/inward/record.url?scp=85163985525&partnerID=8YFLogxK

U2 - 10.1016/j.biortech.2023.129429

DO - 10.1016/j.biortech.2023.129429

M3 - Article

C2 - 37392964

AN - SCOPUS:85163985525

SN - 0960-8524

VL - 385

JO - BIORESOURCE TECHNOLOGY

JF - BIORESOURCE TECHNOLOGY

M1 - 129429

ER -