Life Cycle Assessment of flax fibre for the reinforcement of composites

1. Life Cycle Assessment of flax fibre for the reinforcement of composites Nilmini Dissanayake,John Summerscales, Stephen Grove and Miggy Singh

2. 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

3. 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

4. Why Flax ? • flax is the most agro-chemical intensive bast fibre used as reinforcement • other bast fibres may be “greener”provided yield/hectare andperformance/durability are satisfactory

5. 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, 1987via http://www.flaxcouncil.ca/images UK harvest

6. 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

7. Life Cycle Assessment (LCA) Interpretation Goal and Scope Definition Inventory Analysis Impact Assessment

8. 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 Eflax = 42 GPa  equal specific modulus) • Co-products allocated burdens only for post-separation handling

9. System Boundaries seed, fertiliser, pesticides, diesel machinery Crop Production Dry, green flax stems Retting diesel, machinery, water Dry, retted flax atmospheric emissions, emissions into water, co-products and waste Scutching electricity Scutched long fibre Hackling electricity SLIVER Wet Spinning electricity, water YARN

10. Life Cycle Inventory (LCI) Three scenarios linking different tillage and retting methods: • No-till & water retting - minimum impact? 2. Conservation till (chisel) & stand/dew retting - average impact? 3. Conventional till (mouldboard) & bio-retting - maximum impact?

11. Tillage Methods

12. Fibre Processing

13. Mass loss during the production < Sliver

14. LCI results – energy consumption

15. Energy consumption - breakdown Scenario 1- Sliver (54 GJ/tonne)

16. LCI results – energy consumption

17. Energy consumption - breakdown Scenario 1- Yarn (80GJ/tonne)

18. Energy consumption

19. Energy consumption UK: http://www.decc.gov.uk/en/content/cms/statistics/fuel_mix/fuel_mix.aspx France:http://ieepa.org/news/Other/20100917174353200.pdf

20. Environmental Impact Classification Factors From Adisa Azapagic (and ISO 14047) Acidification Potential (AP) Aquatic Toxicity Potential (ATP) – ecotoxicity Eutrophication Potential (EP) - nitrification Global Warming Potential (GWP) - climate change Human Toxicity Potential (HTP) Non-Renewable/Abiotic Resource Depletion Potential (NRADP) Ozone Depletion Potential (ODP) Photochemical Oxidants Creation Potential (POCP) – smog Draft BS8905 adds “land use”

21. 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)– ecotoxicitybased on the maximum tolerable concentrations of different toxic substances in water by aquatic organismswhat about insects and birds ? • Eutrophication Potential (EP)– nitrificationthe 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 changecaused 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 atmosphererelatively difficult to quantify climate change

22. 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 smogrelated to the potential for VOCs and oxides of nitrogen to generate photochemical or summer smog

23. Environmental Impact for Flax fibre : See also http://www.netcomposites.com/downloads/03Thurs_Summerscales.pdf - slide 15

24. Life Cycle Inventory Analysis (LCI)

25. Life Cycle Impact Assessment – LCIA methodology In the impact assessment interpretation of the LCI data, Environmental impact potential, where: Bjx = burden (release of emission j or consumption of resource j per functional unit) ec1= characterisation factor for emission j continues …

26. Non-renewable/abiotic resource depletion potential is calculated using : Where: Bj = burden (consumption of resource j per functional unit) ec1= 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

27. Life Cycle Impact Assessment (LCIA) For the production of flax sliver continues …

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

29. No-till/water-ret flax vs glass fibres… GF data from Sustainability at Owens Corning – 2008 Summary Progress Report

30. However …. • our analysis uses100% burden to long fibre • economic apportionment:If long fibre = 10% weight at 90 p/kgand short fibre/dust = 90% at 10p/kg,then burdens on long fibre halved • if mass apportionment (indefensible?), then long fibre burden reduced to ~10%

31. A Le Duigou et al, JBMBE, 2011. • environmental impact analysis onFrench flax fibers using different underlying assumptionsto Dissanayake et al for UK fibersconcluded that“without the allocation procedurethe results from the two studieswould be similar.”

32. 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 CO2 sequestration • Higher level of nuclear power in the French energy mix • UK study allocated all burdens to fiberFrench study allocated on mass of product and co-products

33. This study did not address: • sequestration of CO2 • use phase – assumed comparable to glass • disposal – flax could be compostedbut 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).

34. This study did not address: • glass fibres are inert • natural fibres burn GJ/tonne* • Flax (Top-F) 16.36±0.05 • Hemp (Strick H) 17.20±0.24 • Jute (Wingham) 17.46±0.14 • Jute (Virk) 17.75±0.17 • but that will release the sequestered CO2 * Parr 1356 bomb calorimeter data by Adam Smith

35. However … • long flax fibre could bea by-product/co-productif flax grown for seed (Ω3 health food) • … but more difficultto separate fibre from stem

36. 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)

37. 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

38. Conclusions II • the validity of the “green” case for substitution of glass fibres by natural fibres is dependent on the chosen reinforcement form, associated processes and allocation of burdens • 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

39. PhD thesis as free download: http://pearl.plymouth.ac.uk/handle/10026.1/483

40. Thank you for your attention. Any questions? http://www.tech.plym.ac.uk/sme/acmc/lca.htm