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Strategies for Recovery of Energy and
Chemicals from Biomass
Prof Michael K. Theodorou, Prof Andreas Hornung
Dr Marie Kirby, Dr Miloud Ouadi, Dr Matthew Reilly, Dr Trish Toop
Harper Adams University, Agricultural Centre for Sustainable Energy Systems (ACSES)
Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT
Department of Chemical Engineering, University of Birmingham
Presentation Content
1. EPSRC Challenge Grant
To improve the overall net energy yield obtained from organic fraction
municipal solid waste through a combination of thermal pyrolysis and
anaerobic digestion
Aston University, University of Southampton, The Open University,
University of Leeds, Harper Adams University, Fraunhofer UMSICHT
2. Thermo-Catalytic Reforming (TCR®)
3. Anaerobic Digestion Research at Harper Adams
Municipal Solid Waste (MSW)
• UK produces approximately 26.8 million tonnes of household municipal solid waste per year
– represents 14% of the total waste
• In 2013, average MSW produced per person was 403kg
• Estimated to increase by a further 10% by 2020
Paper/card19%
Organic (Food & Biomass)
32%
Textiles2%
Fines6%
Misc. combustible
14%
Misc. Non combustible
6%
Metals8%
Glass5%
Plastics8%
Composition of MSW Waste UK Average (2020)
Source: Renewable Power Association
Sorted OFMSW…
Municipal Solid Waste
• Diameter of 1 to 10 mm
• Granulated Structure
• Moisture Content of 24.5 wt%
• HHV of 13.7 MJ/kg
• LHV of 12.8 MJ/kg
• Size: Lab scale, 2 kg per hour
• Heat Source: Electrically heated
• Design: Lab scale (TRL 3)
• Purpose: Initial feasability testing of materials
Size: Pilot plant, 30 kg per hour
Heat Source: Electrically heated
Design: Pilot scale (TRL-4)
Purpose: Long duration and CHP testing
Size: Demonstrator, 300 kg per hour
Heat Source: Thermally heated (biomass source)
Design: Demonstration scale (TRL-5/6)
Purpose: Fully decentralised renewable CHP
system
Sewage Sludge Park & Garden
Wastes
Cattle Manure Gasifier ResiduesChicken
Manure
Industrial Sludges
Straw Residues
Digestate Compost Residues
Paper / Plastics
Woody Biomass
Food WasteBiosludge
Leaf Litter
& Weeds
Separated MSW
Target feedstocks for Thermo-Catalytic Reforming Process - TCR ®
Thermo-Catalytic Reforming of the OFMSW
• Auger temperature 450 oC
• Residence time of 8 minutes
• Three different reforming (box) temperatures:
– 450⁰C, 600⁰C, 700⁰C and 700⁰C with steam reforming (SR)
• OFMSW did not require pelleting
Influence of Reforming Temperature on Pyrolysis Products
from OFMSW.
Reforming
Temperature Char (%) Gas (%) Oil (%) Water (%)
450 oC 45.9 13.6 5.9 34.6
600 oC 42.2 27 3.1 27.7
700 oC 34.6 34.6 2.2 28.5
700 SR oC 39.6 36.2 2.7 21.5
Auger temperature kept constant at 450 oC
Summary of Analysis of TCR products
Heating value of gas increased with increasing reforming
temperature (9.9 – 17.0 MJ/kg).
Relatively constant oil composition (low ash, low O2 , very high HV)
(good for use in an engine).
Char has a very high ash content (78-85 wt %) (coal replacement
fuel)
Little variation in elemental analysis of pyrolysis water although
COD decreased considerably with increasing reforming temperature
COD ranged from 76 – 23 g/l
Composition of pyrolysis water (GCMS)
• 450ᵒC – 42 different components
• 600ᵒC – 53 different components
• 700ᵒC – 56 different components
• 700ᵒC SR – 61 different components
• Factorial experiment
4 pyrolysis water treatments
5 inclusion levels (2:1, 4:1, 8:1,
16:1, 32:1) loaded on a COD basis
Also included a control (cellulose) and blank
Replicated 3 times (total 66 x 3 assays)
Reforming
Temp Pyrolysis water inclusion ratio (inoculum: pyrolysis water
2:1 4:1 8:1 16:1 32:1
400 oC - + + + +
600 oC - - - + +
700 oC - - - - +
700SR oC - - - - +
Biomethane Potential Test (BMP) of
Pyrolysis Water
+ ve = positive methane production relative to control
- ve = negative methane production relative to control
Methane Yield ranged from 0 – 100 mg/ml COD
Concluding remarks (positive)
Pyrolysis of the organic fraction of MSW is feasible
Integration of pyrolysis with AD can produce additional biogas
AD can be used as a method to treat pyrolysis water
Concluding remarks (negative) Pyrolysis water can inhibit initial digestion
Inhibition dependent on reforming temperature and the loading rate
Anaerobic Digestion of TCR Pyrolysis Water from
OFMSW
Silage
TransportFuels
Developing an integrated supply and processing pipeline for the sustained
production macroalgae-derived hydrocarbon fuels.
MacroBioCrude
TCR Pyrolysis
Redivivus
The recovery of water and nutrients following anaerobic
digestion of food waste
• Effluent from digesters contain fertilising nutrients (N,P,K)
• Nutrients are dilute and pose problems for transportation and
land spreading
• Discharged effluents from farms need to meet legal
requirements (COD/BOD/Heavy metals)
• Economically recover nutrients in a concentrated form and
recycle polished water
The Challenge
Electrocoagulation (EC)
23
• EC uses electrolysis to generate metal ions in water which cause some solute chemicals to coagulate
• EC removes soluble phosphates from digestate and also complex organics that co-coagulate
• Coagulation results in a concentrated sludge that can be processed to recover chemicals
25
Fe Electrocoagulation and filtration of food waste digestate
Electrocoagulation Control
Filtered digestate
Filtered digestate +/-
electrocoagulation
Turbidity (NTU) >90 %
Chemical
oxygen
demand (COD)
>85%
a
Agro-cycle – valorisation of waste feedstocks
• Demonstrate wet AD
• Process poultry manure using dry AD
Summary Slide: Strategies for Recovery of Energy and
Chemicals from Biomass.
Integration of pyrolysis with AD can leads to enhanced energy
production but response is dose dependent and can be negative.
Note that pyrolysis water is rich in organic chemicals.
Preserved seaweed is a novel form of biomass for biofuel production
Electrocoagulation is an effective methodology for recovery of
phosphate-rich sludge from AD digestate.
Ammonia stripping and dry AD can be used for recovery of energy
and chemicals from poultry litter for fertiliser production.
Taught PgC Renewable Energy
https://www.harper-adams.ac.uk/courses/postgraduate/201144/renewable-energy