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Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 1
Saran Sohi and Ondrej MasekSchool of GeoSciences, University of Edinburgh
UK Biochar Research Centre (UKBRC)www.biochar.ac.uk
Biochar and biochar systems – specificity and flexibility
FOREBIOM Workshop, Eskisehir, 6th June 2014
1. Properties and function2. Flexibility in properties3. Specificity of properties4. Systems definition5. Conclusions
Outline
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 2
Biochar properties – native and non-native
Photo: Ondrej Masek
• Some functions common to soil organic matter, but without the turnover of carbon (so some long-term / permanent effects of single additions);
• The material stability of biochar carbon does not mean that biochar is inert – in fact it is multi-functional;
• Initial properties are also NOT necessarily a guide to longer-term function, e.g. beyond first year.
Are functions synergistic, additive and exclusive? Are they predictable? Can they be manipulated?
We developed a screening toolkit (a set of functional tests) to help examine this…
Biochar functions in soil
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 3
ConclusionsExamining consistency and specificity of properties through twelve standard biochars…
Photo: Ondrej Masek
Consistency in the conversion phase
Masek et al., in prep
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 4
Function versus properties
Sohi et al. In Prep.
Type Function Purpose Durationphysical porosity bulk density years;
texture water retention changingchemical base minerals pH and nutrient months;
(ash) recycling decreasingchemical exchange N-use efficiency decades;
capacity GHG mitigation increasingchemical adsorption hydrophobic days;
(micropores) compounds saturatedbiological volatiles hormesis <days;
induced resist. exhaustedbiological microbial stable surfaces decades;
attachment saturated
Biochar is multifunctional. These functions are not constant over time…
Sohi et al. In Prep.
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 5
Potential flexibility of biomass conversion using pyrolysis – but also specificity to the system used.
Investigated by statistical (multi variable) approach:
�30 samples from 30 production facilities
�HTC, microwave, fast, slow, gasification, batch, continuous, rotary, auger, downdraft, updraft, etc.
�Scales from grams to tonnes per hour with nominal operating conditions
�Hardwood, softwood, waste wood, wood pellets, straw, sludge, digestate, municipal waste, etc.
The range in biochar (functional) propertiesalso “influenced by 13 pyrolysis parameters”1
1 Cordner Peacocke, British Biochar Foundation meeting, June 2013
Blanket 100-yr stability values assumed in LCAs
• Quantifying the specific 100-yr stability of biochar refines – and often increases – the C abatement value…
0
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0 200 400 600 800 1000 1200
Sta
ble
C (
%)
Reported pyrolysis temperature (oC)
• Taking carbon storage function as an example: screening 100-yr carbon stability by accelerated ageing; “pyrolysis temperature” is not adequate as sole predictor of function...
– the range for one (functional) property
Sohi et al. In Prep.
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 6
Studies of pyrolysis<>properties using different single materials using one set of equipment – clear trends emerge, e.g…
Predictability for pure feedstock materials?
0
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Pyrolysis temperature
Car
bon
stab
ility
(%
)
Willow slow heat rate (stable%)Willow fast heat rate (stable%)Willow slow heat rate (fixed C%)Willow slow heat rate (fixed C%)
Crombie et al., unpublished data
Multiple functions obtained by mixing and blending?
Sohi et al. (2014) In: Biochar for Environmental Management, 2nd Ed.
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 7
ORS straw large scaleBarley straw bales small scale
waste wood (large-scale) Sawmill residues
Arboricultural arisings Wheat straw bales large scale
barley straw bales large scale
greenwaste, domestic food (large-scale)
ORS straw small scale
Forestry residue (chips) Short rotation coppice (chips) (large-
-300
309298
298229229
125
-117
Ø 178
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Short rotation forestry (chips)
138196
-220
-117
416404360
342309
Commercial & industrial (C&I) animal & vegetable waste (l Imported Canadian forestry (chips) Miscanthus (chips) (large-scale) SRC chips (small scale)
wheat straw bales small scale
sewage sludge (large-scale)
cost (£ per tonne CO2e)
Cost(£ tC-1)
vedo
m
Cumulative C sequestered
GBP t-1biochar
Feedstock is no.1 of thirteen influences – choice afecetd by feedstock price – and biochar value
VeDom
arge scale
Shackley et al. 2011. Carbon Management, 3:335–356
Viable feedstock will often be mixes.
If these mixes vary over time (e.g. seasonal changes in green waste) - how will product properties be affected?
Can we predict – rather than make and analyse –biochar in all permutations of mixing?
Mixing and blending…?
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 8
0
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Post-Pyro450
Post-pyro550 deg
Pre-pyro550 deg
Post-pyro700 deg
Pre-pyro700 deg
Sta
ble
C (
% b
ioch
ar C
)
Expected
Actual
Interactions between feedstock types occur during pyrolysis and after…
UKBRC - In Prep.
USE PHASE
environmental context
transport, storage distribution and application of biochar
quality of products quantity of products
transport and infrastructure
socio-economic context
deployment equipment
LAND SYSTEM(contaminated and degraded)
CLIMATE SYSTEM(C abatement)
ENERGY SYSTEM(export or transport for us
of energy co/products)
markets
regulations and standards
FARMING SYSTEMAgriculture Horticulture
Research focused narrowly on production processes and biochar function in end-use context
Sohi et al. (2014) In: Biochar for Environmental Management, 2nd Ed.
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 9
WASTE SYSTEM
production, transport, storage and preparation of feedstock
FARMING SYSTEM
processing technology
feedstock availability
land availability tenure and
ownership
labour supply
transport and infrastructure
environmental context
socio-economic context
BIOMASS PHASE
CONVERSION PHASE
conversion of prepared feedstock to biochar and co-products
environmental context socio-economic
context
technology innovation
labour supply
effects of processing conditions effects of processing conditions
Sohi et al. (2014) In: Biochar for Environmental Management, 2nd Ed.
Aspects of system spatial scale and structure overlie the socio-economic context and system categories:
• Reach – what is the maximum separation of any two elements in biomass, conversion and use?
• Ubiquity – over what spatial / geographic range does the system replicate?
• Intensity – what proportion of land or production within a region is involved in the system?
• Directionality – is biochar used on land that produces the biomass or is there a net transfer?
Feedstock and system characteristics
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 10
Tokyo sewage sludge pyrolysis plantPhoto: Ondrej Masek
Biochar production – physical (unit) scale
Pyreg containerised systemPhotos: Jim Hammond
Biochar production – physical (unit) scale
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 11
Biochar will not be at the centre of the connected wider systems. Acceptance into systems affected by:
• Markets – existing products, brands and current / future resource supply / contracts;
• Social – end-user acceptability: familiarity (risk, quality,…), future availability, equity / equality;
• Policy – public perceptions and priorities, leadership and risk, time horizons;
• R&D – high rates of technology innovation.
Inter-disciplinary programmes essential, engaging business, industry, regulators and policy makers.
Opportunities must be assessed alongside “fit”
• Biochar for bulk use from major non-virgin biomass sources (e.g. sewage sludge) – use nutrient value and require rules for matching; needs standards / management of feedstock and process;
• Biochar as a (minor) ingredient to distributed products e.g. growing media, fertiliser, animal feed. Function will be facilitated / engineered / positioned, with added value exceeding additional cost.
Initial use may be inversely proportional to the ultimate scale of production and use. This changes the relevant stakeholders and investors in R&D – but all experience supports later large / very large scale use...
Conclusions
Dr Saran [email protected]
UK Biochar Research CentreUniversity of Edinburgh, UK 12
University of Edinburgh
Prof Stuart Haszeldine
Researchers
Simon ShackleySarah GreenwoodKyle CrombieAndrew CrossClare PetersUKBRC team
Sponsors:
Acknowledgements