Hydrothermal
Carbonisation (HTC)
for the Treatment of
AD Digestate
Sarah Farthing, Colin Snape, Jon McKechnie
Centre for
Doctoral Training in
Sustainable Chemistry
What can we do with AD digestate?
Low economic return
Nutrient level policies
Regional and seasonal restrictions
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
Anaerobic
Digestion Digestate
Crop
Growth
Land
Application
?
What can we do with AD digestate?
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
High moisture content =
High drying requirement
Anaerobic
Digestion Digestate
Thermal
Treatment
Hydrothermal Carbonisation
CO2-rich gas
Hydrochar
Process Liquid
Wet Digestate
HTC Reactor
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
Hydrothermal Carbonisation, but:
How?• Operating conditions
• Integration opportunities
Where?• Feedstock selection
• Plant scale
When?• Policy
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
Hydrochar Energy Content (MJ)
=
How? – Modelling
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
+
Pro
cess
Model
Experi
menta
l Work
Hydrochar Energy Content(MJ/kg)
Hyd
roch
ar E
nerg
y C
onte
nt(
MJ/kg)
How? – Integration
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
How? – Integration
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
How? – Integration
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
Where and when? –Techno-economics + LCA
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
• Economic analysis
• CAPEX and OPEX of HTC
• Different configurations
• Life Cycle Assessment
• Fossil energy use
• CO2 emissions
• Water use
Summary
Digestate ››› Hydrothermal Carbonisation (HTC) ››› Scope ››› Modelling ››› Integration ››› Feasibility ››› Summary
Hydrothermal Carbonisation of Digestate
Understanding: operation, opportunities, potential
Acknowledgements
Supervisors: Jon McKechnie and
Colin Snape
Experimental support: Clement Uguna
and Robert Stirling
CDT in Sustainable Chemistry
SPT Research Group
EPSRC