Kinetics of faecal biomass hydrothermal carbonisation for hydrochar production
journal contribution
posted on 2013-06-07, 09:03authored byEric Danso-Boateng, Richard Holdich, G. Sharma, Andrew Wheatley, M. Sohail (Khan), Simon MartinSimon Martin
Decomposition kinetics of primary sewage sludge (PSS) and synthetic faeces (SF), of various moisture
contents, were investigated over different reaction times and temperatures using a hydrothermal batch
reactor. Solid decomposition of PSS and SF was first-order with activation energies of 70 and 78 kJ/mol,
and pre-exponential factors of 4.0 106 and 1.5 107 min 1, respectively. Solid decomposition was significantly
affected by reaction temperature more so than reaction time. Higher temperature resulted in
higher solids conversion to hydrochar. Equilibrium solid hydrochar yields (relative to the original dry
mass used) were 74%, 66%, 61% and 60% for PSS at 140, 170, 190 and 200 C respectively, and 85%,
49%, 48% and 47% for SF at 140, 160, 180 and 200 C respectively. Energy contents of the hydrochars from
PSS carbonised at 140–200 C for 4 h ranged from 21.5 to 23.1 MJ/kg, and increased following carbonisation.
Moisture content was found to affect the Hydrothermal Carbonisation (HTC) process; feedstocks
with higher initial moisture content resulted in lower hydrochar yield and the extent of carbonisation
was more evident in feedstock with lower moisture content. The results of this study provide information
useful for the design and optimisation of HTC systems for waste treatment.
Funding
This research was part of Gates Foundation: "Reinventing the
Toilet".
History
School
Architecture, Building and Civil Engineering
Research Unit
Water, Engineering and Development Centre (WEDC)
Citation
DANSO-BOATENG, E. ... et al., 2013. Kinetics of faecal biomass hydrothermal carbonisation for hydrochar production. Applied Energy, 111, pp. 351 - 357