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Biorefinery of sunflower whole plant was performed successfully using a thermo-mechano-chemical twin-screw reactor. This led to the aqueous extraction of oil and other biopolymers like proteins, pectins and non pectic sugars. It resulted in the overall fractionation of biomass, thus allowing a complete valorization of the input. This biorefinery process was not only efficient but it was also environment-friendly. In addition, it contributed to the production of different end products for various industrial applications. Firstly, the hydrophilic phase will be recycled to the process. Secondly, the densest oil-in-water emulsion is a promising candidate for the formulation of cosmetic creams. Thirdly, the upper hydrophobic phase will be usable for the waterproofing treatment of the surface of agromaterials by coating. Its demixing will also lead to the production of proteins with tensioactive properties. These will serve for the food industry. Lastly, the cake was a mixture of plasticized proteins and lignocellulosic fibers. It was thus considered as a natural composite. Its molding into cohesive fiberboards was conducted successfully using both thermopressing and compression molding processes. The self-bonded boards with high density will be suitable for use as load bearing boards in dry conditions (floor underlayers, interior partitions, furniture, etc.). Positioned in walls and ceilings, boards with medium and low density will contribute to the heat insulation of buildings. In addition, the bulk cake will be also usable as a loose fill insulation material. As proposed, this flow chart thus allows a valorization for all fractions originating from the twin-screw reactor., Le bioraffinage du tournesol plante entière a été réalisé avec succès en utilisant un réacteur thermo-mécano-chimique bi-vis. Cela a permis l’extraction aqueuse de l’huile et d’autres biopolymères tels que des protéines, des pectines et des sucres non pectiques. Un fractionnement total de la biomasse a été obtenu, permettant ainsi une valorisation complète de la matière entrante. À la fois efficace et respectueuse de l’environnement, cette bioraffinerie a généré plusieurs produits finaux pour diverses applications industrielles. Tout d’abord, la phase hydrophile pourra être recyclée en tête de procédé. Puis, l’émulsion huile/eau la plus dense pourra être utilisée pour la formulation de crèmes cosmétiques. Pour sa part, la phase hydrophobe supérieure sera utilisable pour le traitement de surface des agromatériaux par enduction afin de les rendre moins sensibles à l’eau. Sa démixtion facilitera également l’obtention de protéines tensioactives, utilisables dans l’industrie alimentaire. Enfin, le tourteau étant un mélange de protéines plastifiées et de fibres, il a été considéré comme un composite naturel, moulable en panneaux de fibres cohésifs par thermopressage ou par moulage par compression. Les panneaux auto-liés de haute densité pourront être utilisés comme des panneaux travaillants, utilisés en milieu sec (sous-couches pour le sol, cloisons intérieures, meubles, etc.). Positionnés dans les murs et les plafonds, les panneaux de densité moyenne ou faible pourront servir à l’isolation thermique des bâtiments. Par ailleurs, le tourteau pourra aussi être utilisé comme isolant en vrac. Tel que proposé, ce schéma de procédé permet ainsi une valorisation de toutes les fractions provenant du réacteur bi-vis.

The objective of this study is to evaluate the feasibility of an aqueous process for the biorefinery of sunflower whole plant using a co-rotating twin-screw extruder. Traditionally, aqueous extraction of oil is looked upon as an environmentally cleaner alternative technology to the solvent extraction (Rosenthal et al., 1996) and the twin-screw extruder carries out three essential unit operations continuously: conditioning and grinding of whole plant, liquid/solid extraction and liquid/solid separation. Wringing out the mixing is favoured thanks to the stalk fibers. However, drying of the cake meal is not optimal and lixiviation of cotyledon cells within the seed is incomplete. Extraction efficiency depends on the operating conditions: screw rotation speed, input flow rates of whole plant and water. In best conditions, oil yield is 57% and residual oil content in the cake meal is 14%. These conditions lead to the co-extraction of proteins, pectins and hemicelluloses. Protein yield is 44% and residual protein content in the cake meal is 7%. Oil is extracted in the form of two oil-in-water emulsions stabilized by phospholipids and proteins at interface. An aqueous extract containing part of the water-soluble constituents from whole plant, mainly proteins and pectins, is also generated. As a mixture of fibers and proteins, the cake meal can be moulded by thermo-pressing. Panels have promising mechanical properties in bending.

Biorefinery of sunflower whole plant can be conducted with water using a nine modules Clextral Evolum HT 53 twin-screw extruder (TSE). Aqueous extraction of oil is an environmentally cleaner alternative technology to solvent extraction. TSE carries out three unit operations: conditioning and grinding, liquid/solid (L/S) extraction and L/S separation. The compressing action by the reverse screws (CF2C) is essential for L/S separation. Positioned in module 9, CF2C screws push part of the mixture upstream against the general movement in TSE, and this counter pressure ensures the L/S separation efficiency above the metal filter, located in eighth position. Oil is extracted in the form of two emulsions, stabilized by phospholipids and proteins, and usable as co-emulsifiers in cosmetic industry. An aqueous extract containing water-soluble components from whole plant is also generated; it could be recycled. As a mixture of fibers and proteins, the cake can be moulded by thermo-pressing into boards, usable in the furniture and building industries. In this study, fractionation was conducted from next inlet flow rates: 54 kg/h solid and 183 kg/h water (3.4 L/S ratio). The screw speed varied from 249 to 124 rpm, corresponding to a filling coefficient (ratio of the solid inlet flow rate to the screw speed) from 217 to 436 g/h rpm. The filling coefficient directly affects the L/S separation efficiency. The latter can be estimated from next experimental data: the outlet flow rates of both cake and filtrate, the cake moisture content, the residual contents of oil and water-soluble components in the cake, and the extraction yields in dry matter, lipids and water-soluble components. For low filling coefficients (i.e. high screw speed), the L/S mixture compression in CF2C screws is insufficient, not allowing a satisfactory L/S separation. Conversely, for high filling coefficients (i.e. low screw speed), solid particles accumulate more upstream from the pressing zone, obstructing part of the filtering screens and thus reducing the filtration surface. A less efficient L/S separation is then observed. From the experimental data evolution, optimal screw speed was estimated at 182 rpm using a second order polynomial regression, corresponding to a filling coefficient of 297 g/h rpm. Extraction yields in dry matter, lipids and water-soluble components were 22%, 49% and 40%, respectively. Such filling would lead to a specific mechanical energy of 103 W/h kg whole plant processed.

International audience; New thermal insulation fiberboards were manufactured by compression molding from a cake generated during the sunflower biorefinery. Fiberboards were cohesive mixtures of a natural binder and lignocellulosic fibers from sunflower cake. The natural binder ensured the board cohesion, and fibers acted as reinforcing fillers. The influence of molding conditions, i.e. binder type and binder content, on board density, mechanical and heat insulation properties was examined. The medium-density board containing 20% starch-based binder was a good compromise between mechanical and heat insulation properties (78 mW/m K thermal conductivity). It could be positioned on walls and ceilings for thermal insulation of buildings.

International audience; The objective of this study was to manufacture new thermal insulation fiberboards by thermo-pressing. The starting material was a slightly deoiled cake (17.6% oil content), generated during the biorefinery of sunflower (Helianthus annuus L.) whole plant in a co-rotating (Clextral BC 45, France) twin-screw extruder. All fiberboards produced were cohesive mixtures of proteins and lignocellulosic fibers, acting respectively as binder and reinforcing fillers in what could be considered as a natural composite. The molding experiments were conducted using a 400 ton capacity heated hydraulic press (Pinette Emidecau Industries, France). The influence of molding conditions on board density, mechanical properties and heat insulation properties was examined. Molding conditions included mold temperature (140-200°C), pressure applied (150-250 kgf/cm²) and molding time (40-76 s), and these greatly affected board density and thus the mechanical and heat insulation properties. Board density increased with increasingly extreme molding conditions, rising from 500 to 858 kg/m³. The mechanical properties increased at the same time (from 52 to 660 kPa for flexural strength at break, from 5.9 to 49.4 MPa for elastic modulus, from 0.5 to 7.7 kJ/m² for Charpy impact strength, and from 19.2 to 47.1° for Shore D surface hardness). Conversely, heat insulation properties improved with decreasing board density, and the lowest thermal conductivity (88.5 mW/m K at 25°C) was obtained with the least dense fiberboard. The latter was produced with a 140°C mold temperature, a 150 kgf/cm² pressure applied and a 40 s molding time. A medium mold temperature (160°C) was needed to obtain a good compromise between mechanical properties (272 kPa for flexural strength at break, 26.3 MPa for elastic modulus, 3.2 kJ/m² for Charpy impact strength, and 37.3° for Shore D surface hardness), and heat insulation properties (99.5 mW/m K for thermal conductivity).The corresponding board density was medium (687 kg/m³). Because of their promising heat insulation properties, these new fiberboards could be positioned on walls and ceilings for thermal insulation of buildings. The bulk cake also revealed very low thermal conductivity properties (only 65.6 mW/m K at 25°C) due to its very low bulk density (204 kg/m³). It could be used as loose fill in the attics of houses.

International audience; The objective of this study was to manufacture new biodegradable fiberboards by thermo-pressing. The starting material was deoiled cake (only 0.9% oil content), generated during the biorefinery of sunflower (Helianthus annuus L.) whole plant in a co-rotating twin-screw extruder. All fiberboards were cohesive mixtures of proteins and lignocellulosic fibers, acting respectively as binder and reinforcing fillers. The molding experiments were conducted using a 400 ton capacity heated hydraulic press. The influence of molding conditions on board density, mechanical and thermo-mechanical properties, thickness swelling, and water absorption was examined. Molding conditions included pressure applied (24.5–49.0 MPa), molding time (60–300 s), and mold temperature (156–204◦C), and these greatly affected board density and thus the mechanical and thermo-mechanical properties. Board density increased with increasingly extreme molding conditions, rising from 1162 to 1324 kg/m3. The flexural properties increased at the same time (from 12.2 to 27.7 MPa for flexural strength at break, and from 2183 to 5244 MPa for elastic modulus) and also Shore D surface hardness (from 69.6 to 79.0◦). Conversely, Charpy impact strength was low and quite independent of thermo-pressing conditions. Statistical analysis of the Doehlert’s experimental design was conducted to determine optimal thermo-pressing conditions for flexural properties, giving 49.0 MPa pressure applied, 300 s molding time, and 204◦C mold temperature. Density of boards molded under these conditions was 1267 kg/m3. Flexural strength at break, elastic modulus and Shore D surface hardness were 30.3 MPa, 5946 MPa, and 81.5◦, respectively, and these corresponded to the highest values for the entire study. Such boards largely complied with French standard NF EN 312, type P4 (i.e. load bearing boards for use in dry conditions) for flexural properties. However, thickness swelling (30%) needs to be slightly reduced to achieve the 21% recommended standard value.

Biorefinery of sunflower whole plant is conducted according to an aqueous process using a twin-screw extruder. Aqueous extraction of oil is looked upon as an environmentally cleaner alternative technology to solvent extraction. Twin-screw extruder carries out three unit operations continuously: conditioning and grinding of whole plant, liquid/solid extraction and liquid/solid separation. Extraction efficiency depends on screw speed, and input flow rates of whole plant and water. In best conditions, oil yield is 57%, and residual oil content in cake meal is 14%. These conditions lead to the co-extraction of proteins, pectins and hemicelluloses. Oil is extracted in the form of two oil-in-water emulsions stabilized by phospholipids and proteins at interface. They could be used as co-emulsifiers for creams production in cosmetic industry. An aqueous extract containing part of the water-soluble constituents from whole plant, mainly proteins and pectins, is also generated. It can be recycled to the process. As a mixture of fibers and proteins, the cake meal can be moulded by thermo-pressing. Denser fiberboards have promising mechanical properties in bending. They could be used in furniture industry. Fiberboards with the lowest densities are more fragile but they could be used for their heat insulation properties in building industry.

International audience; The starting material used in this study was a cake generated during thermo-mechanical fractionation of sunflower (Helianthus annuus L.) whole plant in a Clextral BC 45 (France) twin-screw extruder. It was slightly deoiled (17.6% dry matter for residual oil content), leading to an oil extraction yield of 46.1% (yield based on the residual oil content in cake). As it was a mixture of fibers and proteins, it could be considered as a natural composite that was processed successfully into fiberboards by thermo-pressing. This study aimed to evaluate the influence of thermo-pressing conditions on oil expression yield during molding and on flexural properties of fiberboards manufactured from this cake. An experimental design with three variables was realized: from 250 to 500 kgf/cm² for pressure applied (in 5 levels), from 60 to 300 s for molding time (in 7 levels), and from 600 to 1200 mg/cm² for cake quantity (in 3 levels). Temperature of the aluminium mold positioned between the two plates of the heated hydraulic press (PEI, France) with 400 tons capacity was 200°C. All fiberboards were cohesive. As an internal binder, proteins ensured the agromaterial cohesion, and fibers entanglement also acted like reinforcement. Thermo-pressing was not only a molding operation. It also consisted in increasing the oil extraction efficiency. Oil expression yield during molding increased with the increase of pressure applied, and especially with the increase of molding time. At the same time, it was not so much influenced by the modification of cake quantity. Highest oil expression yield was 58.8% in proportion to the oil that the cake contained, leading to a total oil yield (oil extracted by water in twin-screw extruder, and oil expressed during molding) of 77.8% in proportion to the oil that the sunflower whole plant contained. It was associated with the next thermo-pressing conditions: 469 kgf/cm² for pressure applied, 300 s for molding time, and 697 mg/cm² for cake quantity. Flexural properties of the corresponding fiberboard were 8.1 MPa for flexural strength at break, and 1778 MPa for elastic modulus. Its thickness was 5.40 mm, leading to a mean apparent density of 1.25. Such flexural strength at break was a bit lower (-25%) than the one of the most resistant fiberboard (10.8 MPa), manufactured from the next thermo-pressing conditions: 250 kgf/cm² for pressure applied, 300 s for molding time, and 807 mg/cm² for cake quantity. For such conditions, oil expression yield was 48.0% in proportion to the oil that the cake contained, leading to a total oil yield close (-8%) to the highest yield obtained (71.9% in proportion to the oil that the sunflower whole plant contained instead of 77.8%). Thermo-pressing of cake from sunflower whole plant led to two actions in a single step: the expression of part of residual oil in cake that contributed to the improvement of the oil extraction efficiency, and the molding of biodegradable fiberboards. Their flexural properties were promising. Moreover, because residual oil content in fiberboards was at least 8.0% dry matter, they were not too water-sensitive (i.e. more durable than other thermo-pressed agromaterials). Such fiberboards were value-added agromaterials that may have direct industrial applications. Indeed, they would be potentially usable as inter-layer sheets for pallets, for the manufacturing of biodegradable containers (composters, crates for vegetable gardening), or for their heat insulation properties in building trade.

Document Type : Proceedings Paper Conference Date : AUG 29-31, 2011 Conference Location : Strasbourg, FRANCE Conference Sponsor : Univ Strasbourg; International audience; The starting material used in this study was a cake generated during thermo-mechanical fractionation of sunflower (Helianthus annuus L.) whole plant in a twin-screw extruder. It was slightly deoiled (16.7% of oil in dry matter). Composed mainly of fibers and proteins, it could be considered as a natural composite and was processed successfully into fiberboards by thermo-pressing. This study aimed to evaluate the influence of thermo-pressing conditions on mechanical and heat insulation properties of fiberboards manufactured from this cake. All fiberboards were cohesive, proteins and fibers acting respectively as binder and reinforcing fillers. Highest cake quantity (1000 mg/cm²) led to the highest breaking load (60.7 N) with a flexural strength at break quite low (2.9 MPa), lowest elastic modulus (216.6 MPa), and highest Charpy impact strength (6.5 kJ/m² for resilience). The increase of pressure applied during molding (from 320 to 360 kgf/cm²) led to an important increase of elastic modulus (from 352.6 to 728.6 MPa). Besides, fiberboard molded at 360 kgf/cm² was the most rigid of this study, and logically revealed the most important Shore D surface hardness (52.6°). Moreover, lowest molding time (60 s) led to the highest flexural strength at break (3.9 MPa). The low density of the fiberboards (less than 0.97) involved promising heat insulation properties. Indeed, thermal conductivity of fiberboards at 25 °C was low (from 103.5 to 135.7 mW/m K), and decreased with the increase of thickness. According to their mechanical and heat insulation properties, fiberboards would be potentially usable as inter-layer sheets for pallets, for the manufacture of biodegradable containers (composters, crates for vegetable gardening) by assembly of fiberboards, or for their heat insulation properties in building industry. Moreover, thermo-pressing was not only a molding operation. It also improved the oil extraction efficiency as a part of residual oil was expressed from cake during molding, and total oil yield reached 79.3% with a pressure applied of 360 kgf/cm².

International audience; Twin-screw extrusion is an original solution for the biorefinery of sunflower whole plant according to an aqueous extraction process. In best operating conditions, oil yield is 57% and residual oil content in the cake meal is 14%. Oil is extracted in the form of two oil-in-water emulsions stabilized by phospholipids and proteins at interface. The cake meal would be suitable for use in animal feeds and for energy production in pellets burning furnaces. As a mixture of fibers and proteins, it is also considered as a natural composite. It can be processed into biodegradable agromaterials by thermo-pressing. During molding, part of residual oil is expressed (until 41% of oil from whole plant), leading to the increase of the total oil extraction yield (aqueous extraction in twin-screw extruder and expression during thermo-pressing): until 81% of oil from whole plant. Panels have promising mechanical properties in bending (until 12 MPa for stress at break). They are usable as inter-layer sheets for pallets, for their sound and heat insulation properties or for the manufacturing of containers by assembly of panels. Their hydrophobic character (8% for residual oil content in the panels) makes them resistant to water.

Twin-screw extrusion is an original solution for the biorefinery of sunflower whole plant according to an aqueous extraction process. In best operating conditions, oil yield is 57% and residual oil content in the cake meal is 14%. Oil is extracted in the form of two oil-in-water emulsions stabilized by phospholipids and proteins at interface. The cake meal would be suitable for use in animal feeds and for energy production in pellets burning furnaces. As a mixture of fibers and proteins, it is also considered as a natural composite. It can be processed into biodegradable agromaterials by thermo-pressing. During molding, part of residual oil is expressed (until 41% of oil from whole plant), leading to the increase of the total oil extraction yield (aqueous extraction in twin-screw extruder and expression during thermo-pressing): until 81% of oil from whole plant. Panels have promising mechanical properties in bending (until 12 MPa for stress at break). They are usable as inter-layer sheets for pallets, for their sound and heat insulation properties or for the manufacturing of containers by assembly of panels. Their hydrophobic character (8% for residual oil content in the panels) makes them resistant to water.

Fractionation of sunflower whole plant is carried out with water in a twin-screw extruder. An extract and a raffinate are produced in a single step. Oil extraction yield is 55%. Lipids are extracted in the form of two oil-in-water emulsions: the higher hydrophobic phase and the lower one. Stability of both hydrophobic phases is ensured by the presence at interface of surface-active agents co-extracted: phospholipids and proteins. Pectins and non pectic sugars complete the dry matter of the lower hydrophobic phase. Hydrophobic phases may have applications for non food uses: biolubricants market, transport of active principles (odours, colours, bactericides, antifungals), and treatment of hydrophilic surfaces. They can be also used for oil production because their demulsification with ethanol is efficient. Oil recovery produces also a precipitate containing proteins with tensioactive properties. The extract contains also a hydrophilic phase (aqueous phase). This largest phase is an extract of the soluble constituents from whole plant: proteins from kernel, pectins from pith and head, and hemicelluloses from stalk. Valorization of hydrophilic phase is difficult because it is much diluted. Nevertheless, it would be potentially recyclable for aqueous extraction. It would be also possible to use it for the production of proteins with surface-active properties and pectins. The raffinate (cake meal) is rich in fibres and proteins with thermoplastic properties. It would be suitable for use in animal feeds and for energy production. It is also a natural composite, and it can be manufactured into biodegradable agromaterials by compression moulding. Panels can be used as inter-layer sheets for pallets or for the manufacturing of containers.

Biorefinery of sunflower whole plant can be conducted with water by thermo-mechano-chemical fractionation in a Clextral BC 45 (France) co-penetrating and co-rotating twin-screw extruder. An extract and a raffinate are produced separately and in a single continuous step. The arrangement of screw profile makes possible to define three successive zones along the barrel, in which the three unit operations of the aqueous extraction process are taking place. (I) The grinding zone consists of a succession of 10 monolobes paddles, and 5 bilobe paddles. It ensures the conditioning and the grinding of solid matter. (II) The extracting zone begins with water injection. It is composed of a second series of 5 bilobe paddles to mix liquid and solid. (III) The pressing zone is the place where liquid/solid separation is realized. Screw configuration is then arranged with reversed pitch screws used to place pressure on the liquid/solid mixture, and positioned immediately downstream from a filter section. Representation of liquid/solid transport inside the barrel is performed thanks to (i) the measuring of the filling of each screw element after visual observation, (ii) the characteristics of the corresponding solid, and (iii) the modelling of the contribution of each screw element to the residence time distribution of solid and liquid phases. Consequently, twin-screw extruder can be represented as the association of a grinder, a liquid/solid extractor, and a liquid/solid separator, in which material exchanges are intensified. Thus, it is possible to predict the evolution of mean residence times of liquid and solid in the three zones of twin-screw extruder with the main operating variables: screw rotation speed, and inlet flow rates of whole plant and water. The decrease of both screw rotation speed and inlet flow rate of whole plant, simultaneously with the increase of inlet flow rate of water, causes the increase of liquid to solid ratio in the extracting zone, and the increase of residence time of solid in the pressing zone. These operating conditions (60 rpm for screw rotation speed, 5.0 kg/h and 20.3 kg/h for inlet flow rates of whole plant and water, respectively) are favourable to an efficient contact between liquid and solid (8.2 for liquid to solid ratio), and to the liquid/solid separation (156 sec for residence time of solid inside the separator). Oil yield is then around 55%, and residual oil content of the cake meal is only 13% of dry weight. The oil is extracted in the form of oil-in-water emulsions. The emulsion stability is ensured at interface by surface-active agents: phospholipids, proteins, and pectins. Extracts are also made up of a hydrophilic phase. This major fraction contains water-soluble components: proteins, and pectins. Raffinates are rich in fibres, and they have also a significant content of proteins with thermoplastic properties. They can be manufactured into biodegradable agromaterials by compression moulding.

L'extraction aqueuse des lipides de la graine de tournesol est étudiée en contacteur agité. La diffusion à l'intérieur des particules est le facteur limitant de l'échange de matière. Les protéines sont impliquées dans l'entraînement et la stabilisation des lipides par l'eau. Le fractionnement de la plante entière est également étudié avec l'eau en extrusion bi-vis. Un extrait et un raffinat sont obtenus séparément et en une seule étape continue. Des rendements d'extraction en huile de 55 % peuvent être obtenus sous forme d'émulsions huile/eau. Leur stabilité est assurée par la présence à l'interface de tensioactifs : les phospholipides et les protéines voire les pectines. Les extraits se composent aussi d'une phase hydrophile. Prépondérante, elle contient des composés hydrosolubles (protéines, pectines…). Riches en fibres, les raffinats présentent une teneur significative en protéines au comportement thermoplastique. Ils peuvent être transformés en agromatériaux par thermomoulage.