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

TCR ® Animation

Integrated Pyrolysis and Anaerobic Digestion

Intermediate and

fast pyrolysis

Anaerobic

Digestion

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 ®

BIO-OIL SYNGAS CHAR

TCR® Product Quality

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

Processing seaweed using TCR® technology

Seeded lines

Seaweed silage

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

22

Electrocoagulation Biochar Trickle FilterAnaerobic Digestion

Proposition

Polished Water

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

• Lab scale electrocoagulation system

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

Thank you for listening!