Life Cycle Assessment

of flax fibre for the reinforcement of composites

Nilmini Dissanayake, John Summerscales, Stephen Grove and Miggy Singh

Fibre-reinforced composites: typical applications

J-boats Poma-Otis mass transit

Images from www.tpicomp.com

Reitnouer flat bed trailer NABI 30-foot bus

Content

      Flax Life Cycle Assessment (LCA)  goal and scope  system boundaries Life Cycle Inventory analysis (LCI)  3 scenarios  energy Environmental Impact Classification Factors (EICF) Life Cycle Impact Assessment (LCIA) - results Conclusions

• • • • •

Flax

Linum usitatissimum temperate zone plant flax – grown for fibre linseed – grown for seed oil sown in March-May in UK life cycle of the plant 45-60 day vegetative period 15-25 day flowering period 30-40 day maturation period

Why Flax ?

•

flax is the most agro-chemical intensive bast fibre used as reinforcement

•

other bast fibres may be “greener” provided yield/hectare and performance/durability are satisfactory

• •

Growth stages

Life cycle of the flax plant consists of • a 45 to 60 day vegetative period, • a 15 to 25 day flowering period and • a maturation period of 30 to 40 days From J A Turner “Linseed Law” BASF (UK) Limited, 1987 via http://www.flaxcouncil.ca/images UK harvest

Flax grown on campus

• • • • 4 x 4 x 2 replicates behind Portland Villas three fertilisers (N, P, K) or none 0, 0.5, 1.0 or 2.0 times recommended level  no significant differences (soil too good ?)

Flax: from plant to fibre

• • • • • • • tillage and growth harvest (combining or pulling) retting (dew-, wet-, stand- or enzyme-retting) – enzymes (e.g. pectinase digests pectin binder) decortication/scutching (hammer mill, fluted rollers, willower) cleaning (removal of shive) carding (brushing/combing aligns fibres)

> sliver

spinning (twisting binds fibres)

> yarn/filament

Life Cycle Assessment (LCA )

Goal and Scope Definition Inventory Analysis Interpretation Impact Assessment



Goal and Scope

To determine the sustainability of natural fibres as reinforcement in polymer matrix composites (referenced to glass fibres)  Cradle-to-factory gate • agricultural operations (from ploughing to harvest) • fibre extraction operations (retting and decortication) • • fibre preparation operations (hackling and carding) fibre processing operations (spinning or finishing)  The functional unit : “one tonne of flax fibres for reinforcement in polymer matrix composites” (assumes E flax = 42 GPa  equal specific modulus)  Co-products allocated burdens only for post-separation handling

System Boundaries

seed, fertiliser, pesticides, diesel machinery diesel, machinery, water electricity electricity electricity, water Crop Production Dry, green flax stems Retting Dry, retted flax Scutching Scutched long fibre Hackling

SLIVER

atmospheric emissions, emissions into water, co-products and waste Wet Spinning

YARN

Life Cycle Inventory (LCI)

Three scenarios linking different tillage and retting methods:

1. No-till & water retting - minimum impact?

2. Conservation till (chisel) & stand/dew retting - average impact?

3. Conventional till (mouldboard) & bio-retting - maximum impact?

Tillage Methods

Mouldboard plough Chisel plough Pass with no soil tillage 0 100 200 300 400 500 600 Energy consumption in ploughing MJ/ha

Fibre Processing

Bio-retting Stand/Dew retting Dessicant Retting + Scutching Water retting 0 20 40 60 80 100 Energy consumption in retting & subsequent scutching process GJ/tonne of yarn

Mass loss during the production

100 90 80 70 60 50 40 30 20 10 0 Scenario-1 Scenario-2 Scenario-3 Crop Production Retting Scutching Hackling Spinning

Remaining mass as a % of green stems at each stage of the production

60 50 40 30 20 10 0

LCI results – energy consumption

90 80 70 Scenario-1 Scenario-2 Scenario-3

Energy use in the production of flax sliver (GJ/tonne)

Energy consumption - breakdown

Scenario 1-

Sliver

(54 GJ/tonne) 4% 9% 1% 17% 69% Agricultural operations Fertiliser/pesticides Warm water retting Scutching Hackling

40 30 20 10 0 90 80 70 60 50

LCI results – energy consumption

Scenario-1 Scenario-2 Scenario-3

Energy used in the production of flax yarn (GJ/tonne)

Energy consumption - breakdown

Scenario 1- Yarn (80GJ/tonne) 30% 2% 12% 6% 49% Agricultural operations Fertiliser/pesticides Warm water retting Scutching Hackling Spinning 1%

Energy consumption

Mat .. sliver

Glass fibre mat No-till & water retting Conservation & stand retting Conventional & bio-retting

Continuous fibre … yarn

Glass fibre No-till & water retting Conservation & stand retting Conventional & bio-retting

GJ/t

54.7

54.4

113 119

GJ/t

31.7

80.4

142 148

Energy consumption

Energy source Coal/Solid fuels Natural Gas Oil Nuclear Renewables Other % in UK

25.8

47.7

18.0

6.6

1.9

% in France

5 14 33 40 6 2

UK:

http://www.decc.gov.uk/en/content/cms/statistics/fuel_mix/fuel_mix.aspx

France:

http://ieepa.org/news/Other/20100917174353200.pdf

Environmental Impact Classification Factors

From Adisa Azapagic (and ISO 14047) 1. Acidification Potential (AP) 2. Aquatic Toxicity Potential (ATP) – ecotoxicity 3. Eutrophication Potential (EP) - nitrification 4. Global Warming Potential (GWP) - climate change 5. Human Toxicity Potential (HTP) 6. Non-Renewable/Abiotic Resource Depletion Potential (NRADP) 7. Ozone Depletion Potential (ODP) 8. Photochemical Oxidants Creation Potential (POCP) – smog Draft BS8905 adds “land use”

EICF definitions I

• • • •

Acidification Potential (AP)

consequence of acids (and other compounds which can be transformed into acids) being emitted to the atmosphere and subsequently deposited in surface soils and water

Aquatic Toxicity Potential (ATP)

– ecotoxicity based on the maximum tolerable concentrations of different toxic substances in water by aquatic organisms what about insects and birds ?

Eutrophication Potential (EP)

– nitrification the potential of nutrients to cause over-fertilisation of water and soil which in turn can result in increased growth of biomass

Global Warming Potential (GWP)

- climate change caused by the atmosphere's ability to reflect some of the heat radiated from the earth's surface: reflectivity is increased by the greenhouse gases (GHG) in the atmosphere relatively difficult to quantify climate change

EICF definitions II

• • • • Human Toxicity Potential (HTP) persistent chemicals reaching undesirable concentrations in each of the three elements of the environment (air, soil and water) leading to damage to humans, animals and eco-systems Non-Renewable/Abiotic Resource Depletion Potential (NRADP) depletion of fossil fuels, metals and minerals Ozone Depletion Potential (ODP) potential for emissions of chlorofluorocarbon (CFC) compounds and other halogenated hydrocarbons to deplete the ozone layer

Photochemical Oxidants Creation Potential (POCP)

– summer smog related to the potential for VOCs and oxides of nitrogen to generate photochemical or summer smog

:

Environmental Impact for Flax fibre

Environmental Impact Classification Factor

Acidification Potential (AP ) Aquatic Toxicity Potential (ATP) Eutrophication Potential (EP) Global Warming Potential (GWP) Human Toxicity Potential (HTP) Non-Renewable/Abiotic Resource Depletion (NRADP) Ozone Depletion Potential (ODP) Photochemical Oxidants Creation Potential (POCP)

Noise and Vibration Odour Loss of biodiversity

Very High Effect Low Effect No Effect See also http://www.netcomposites.com/downloads/03Thurs_Summerscales.pdf

- slide 15

Life Cycle Inventory Analysis (LCI)

INPUTS Materials Seed Fertilisers: Lime Ammonium nitrate Triple superphosphate Potassium chloride Pesticides Diesel (using no-till & water retting) Electricity Value (per tonne of yarn) 423 kg 2445 kg (4GJ) 444 kg (25 GJ) 400 kg (6GJ) 305 kg (3 GJ) 9 kg (2 GJ) 5 GJ 36 GJ OUTPUTS Yarn Co-products : Short Fibres Shive Dust Coarse plant residues Direct Emissions : CO 2 NH 3 N 2 O NO x SO 2 1000 kg 4497 kg 7104 kg 2824 kg 2304 kg 9334 kg 68 kg 14 kg 6 kg 3 kg

Life Cycle Impact Assessment – LCIA methodology

In the impact assessment interpretation of the LCI data,

Environmental impact potential

, where: B jx ec 1 = burden (release of emission j or consumption of resource j per functional unit) = characterisation factor for emission j continues …

Non-renewable/abiotic resource depletion potential

is calculated using : Where: B ec j (consumption of resource 1 = burden j per functional unit) = estimated total world reserves of resource j .

As defined by Adisa Azapagic et al (2003, 2004) in Polymers, the Environment and Sustainable Development and Sustainable Development in practice – case studies for engineers and scientists

Life Cycle Impact Assessment (LCIA) For the production of flax sliver

ATP HTP 40 GWP 30 20 10 0 ODP AP No-till & water retting Conservation & dew retting Conventional & bio-retting POCP EP

continues …

HTP

Life Cycle Impact Assessment (LCIA) For the production of flax yarn

ATP 40 GWP 30 20 10 0 ODP No-till & water retting Conservation & dew retting AP Conventional & bio retting POCP EP

No-till/water-ret flax

vs

glass fibres…

HTP 50 GWP 40 30 20 10 0 ODP Yarn (yarn) Sliver (sliver) POCP AP EP GF data from Sustainability at Owens Corning – 2008 Summary Progress Report

• • •

This study did not address:

sequestration of CO 2 use phase – assumed comparable to glass disposal – flax could be composted

but

degradation leads to “biogas [which] is typically 60-65% methane, 35% carbon dioxide and a small amount of other impurities” [Jana et al, 2001] S Jana, NR Chakrabarty and SC Sarkar, Removal of Carbon Dioxide from Biogas for Methane Generation , Journal of Energy in Southern Africa, August 2001, 12(3).

A Le Duigou et al, JBMBE, 2011.

• environmental impact analysis on French flax fibers using different underlying assumptions to Dissanayake et al for UK fibers concluded that “without the allocation procedure the results from the two studies would be similar.”

Le Duigou

vs

Dissanayake key differences

• • • • • UK plants desiccated at mid-point flowering but French plants allowed to set seed UK yield only 6000 kg/ha but French yield 7500 kg/ha at harvest UK study excluded photosynthesis and CO 2 sequestration Higher level of nuclear power in the French energy mix UK study allocated all burdens to fiber French study allocated on mass of product and co-products



Conclusions I

no-till and water retting scenario • lowest global warming potential  using bio-retting process • increased global warming • reduced eutrophication, acidification and toxicity  fibre mass as % green flax stems • 5% in bio-retting • 4% in water retting • 2% in dew retting  the embodied energies for flax (no-till agriculture): 54 GJ/tonne for

sliver

(55 GJ/tonne for glass mat) 80 GJ/tonne for yarn (32 GJ/tonne for continuous glass)

However ….

• • • Analysis uses 100% burden to long fibre Economic apportionment: If long fibre = 10% weight at 90 p/kg and short fibre/dust = 90% at 10p/kg, then burdens on long fibre halved Mass apportionment (indefensible?), then long fibre burden reduced to 10%

Burdens from …

minimum < average < maximum

• • • • •

no till <

conservation agriculture

<

mouldboard plough

organic fertiliser <

agro-chemicals

biological control of pests <

pesticides

water <

dew-

<

bio-retting

sliver <

spun yarn

Conclusions II

 the validity of the “green” case for substitution of glass fibres by natural fibres is dependent on the chosen reinforcement form and associated processes  no-till with water retting is identified as the most environmental friendly option  conservation agriculture, organic fertiliser and biological control of pests will improve environmental credentials of flax

PhD thesis as free download:

http://pearl.plymouth.ac.uk/ handle/10026.1/483

Thank you for your attention.

Any questions?

http://www.tech.plym.ac.uk/sme/acmc/lca.htm