METHOD AND SYSTEM FOR SEPARATING A POLYMER FROM A BIOMASS

Abstract

The present invention relates to a a method for separating a polymer from a biomass including melt extrusion of a polymer gel and to a system for separating a polymer from a biomass and to a polymer gel obtained using the aforementioned method. The method comprises the steps of: - providing a biomass comprising a polymer; - providing a solvent to the biomass; - dissolving the polymer in the solvent; - forming a polymer-solvent gel; - providing the polymer-solvent gel to an extruder; - melt processing of the polymer-solvent gel in the extruder at a temperature of at least 40 OC; such that at least 85 wt.% of the solvent present in the polymer-solvent gel is separated by evaporation from the polymer; and - drying the polymer during melt processing to form at least one solid extrudate comprising at most 5 wt.% of solvent; wherein the step of melt processing the polymer-solvent gel in the extruder is performed at a temperature which is at least 3 °C lower than the melting temperature of the polymer.

Description

The present invention relates to amethod for separating a polymer from a biomass including melt extrusion of a polymer gel and to a system for separating a polymer from a biomass and to a polymer gel obtained using the aforementioned method. Over the past years the research and development, as well as the commercial interest, in the manufacture ofbio-based polymers has increased as they may form an alternative for fossil-based, in particular oil-based, plastics. Biobased polymers may be produced in, and extracted from, a biomass, including production methods from waste water and / or organic residual waste, and therewith provide an important source ofbiopolymers. Although methods for separating polymers from biomass have been developed, it has been found that the quality of and / or approach for the polymer obtained using the known methods is insufficient and / or costly formany applications. In particular, the molecular weight ofthe polymers obtained bythe knownmethods is insufficiently controlled formany (higher end) applications and / or products. The present invention aims to obviate or at least significantly reduce the aforementioned disadvantage and aims to provide amethod inwhich higher qualitypolymers canbe obtained reliably and more viably. This objective is achieved with a method for separating apolymer from a biomass including melt extrusion ofa polymer gel comprising the steps of: - providing a biomass comprising a polymer, providing a solvent to the biomass, dissolving the polymer in the solvent, forming a polymer-solvent gel, providing the polymer-solvent gel to an extruder, melt processing ofthe polymer-solvent gel in the extruder at a temperature of at least 40 OC, such that at least 85 wt.% of the solvent present in the polymer-solvent gel is separated by evaporation from the polymer, and drying the polymer during melt processing to form at least one solid extrudate comprising at most 5 wt.% of solvent, wherein the step of melt processing the polymer-solvent gel in the extruder is performed at a temperature which is at least 3 °C lower than the melting temperature ofthe polymer. It is noted that melt processing includes melt extrusion that involves extruding the polymer- solvent gel in the extruder at a temperature ofat least 40 °C. An advantage ofthe method according to the invention is that higher quality ofthe extracted polymer (using solvent extraction) is conserved due to obviating a drying step. It has been found that providing the solvent to the biomass (i.e. providing a liquid mass) allows the melt-processing ofthe polymer solvent gel to be performed at a temperature below the melting temperature of the dried polymer. As a result, degradation ofthe polymer during the extraction process can be substantially prevented / limited, thus leading to a higher quality and in particular a conserved higher molecular weight of the extracted polymer compared to conventional methods. Furthermore, the method according to the invention enables to conserve / maintain the quality and properties ofthe polymers. In addition, the method according to the invention enables separation of the polymers from the biomass without drying the polymer before extrusion. Furthermore, the melting temperature ofthe polymers during extrusion is at least 3 °C lower compared to the melting temperature ofthe dried polymers. Preferably, the separation is performed by ltration and / or gravity separation. Another advantage ofthe method according to the invention is that all desired polymers can be extracted, formulated, blended, and melt processed, in one go. As a result, an efficient and effective method is achieved. Another advantage ofthe method according to the invention is that this method allows for a substantially complete removal and re-use ofthe solvent from the polymer. In view ofthe fact that the solvent is an expensive key element, the re-use thereofprovides that the method according to the invention is, contrary to known methods, economically viable. A further advantage of the method according to the invention is that the extrusion of the polymer can be performed at a reduced pressure ortemperatures compared to the extrusion ofa dried polymer. A further advantage is that the method according to the invention is energetically efficient, because the heat that is required to dry the polymer and for recovery ofthe solvent is used in a single process step after the extraction of the polymer to provide economy of process while conserving quality in steps ofconversion and processing to an extruded article. In an embodiment of the method according to the invention, the melt processing of the polymer-solvent gel may be performed at a temperature in the range of40 °C to 200 °C, preferably in the range of50 °C to 160 °C. An advantage ofthe mentioned temperature range is that the polymermay be extruded with good dimensional stability. A further advantage is that the extruded polymer also exhibits good aesthetic quality at the abovementioned temperature ranges. In otherwords, the extruded polymer is stable at the abovementioned temperatures. A further advantage is that the extruded polymer is substantially free of solvent. In other words, the extruded polymer does not necessarily need to be dried. In an embodiment of the method according to the invention the polymer-solvent gel may comprise atmost 95 wt.% solvent, preferably the polymer-solvent gel may comprise solvent in the range of 5 wt.% to 95 wt.%, more preferably in the range of 5 wt.% to 90 wt.%. An advantage of the abovementioned ranges for the solvent is that the polymer-solvent is provided as a gel that can easily be processed, for example by pelletizing and / or granulating the gel during the method steps. Another advantage is that the solvent content ofthe gel as disclosed above limits the polymer crystallization before extrusion. This enables to decrease the heat necessary to melt the polymer in the gel extrusion to obtain a solid extrudate and increases the quality ofthe extracted polymer even further. Furthermore, a decrease in temperature reduces the decomposition rate ofthe polymer and enables to produce / obtain polymers with (high) average molecular weights. In other words, high quality extrudate is achieved. In an embodiment ofthe method according to the invention, the polymer comprises a polymer blend. It was found that the method according to the invention can be used for single polymers as well as for polymer blends comprising two ormore different polymers. An advantage thereof is that differenttypes ofproducts (based on different types ofpolymers / polymer blends) can be made using the method according to the invention. A further advantage is that the method according to the invention enables to segregate a desired polymer composition in a single process. For example, a desired fraction ofpolymer blend with a specic average molecular weight range and / or crystallinity can be recovered. In other words, the method according to the invention enables selective dissolving and / or solidifying ofthe polymer. Said selective separationmay be achieved by tuning the polarity ofthe solvent. In an embodiment ofthe method according to the invention, the polymermay be one ormore polyhydroxyalkanoate. An advantage of polyhydroxyalkanoate (PHA), such as and polyhydroxybutyrate (PHB), is that these polymers are produced by numerous (micro)organisms in nature and thus inherent capacity exists to produce these polymers in large amounts using biomass derived from organic rich waste products. Another advantage is that polyhydroxyalkanoates, such as polyhydroxybutyrate, are suitable for manufacturing bio-plastics, and with polyhydroxyalkanoates in particular, because these biopolymers are inherently biodegradable. In an embodiment ofthe method according to the invention, the polyhydroxyalkanoates may be one or more selected from the group of short or medium length polyhydroxyalkanoate homopolymers, short or medium length polyhydroxyalkanoate co-polymers, short and / or medium length polyhydroxyalkanoate blends. In an embodiment ofthe method according to the invention the polymermay include one or more monomer selected from the group of 3-hydroxybutyrate, 4-hydroxybutyrate, 3- hydroxyvalerate, 3-hydroxyhexanote, 3-hydroxyoctanoate, 3-hydroxydecanoate, 3- hyrodoxydodecanoate. For example, the polyhydroxyalkanoate may be poly(3-hydroxybutyrate-co-3- hydroxyvalerate).Itwas found thatthe abovementioned (semi-crystalline) polymers and / orpolymers formed by the aforementioned monomers sufciently form a gel with a solvent, for example forming a gel in combination with the solvent 2-butanol. In an embodiment ofthe method according to the invention the step ofproviding a solvent to the biomass further may comprise pre-heating the solvent before said solvent is provided to the biomass. An advantage ofpreheating the solvent is thatthe speed ofdissolving ofthe polymer contained in the biomass in the solvent is increased by the increased temperature. In an embodiment ofthe method according to the invention the step ofdissolving the polymer in the solventmay further comprise heating the solvent and biomass. An advantage ofheating the solvent and biomass in the dissolving step is that it increases the rate with which the polymer dissolves in the solvent, thus providing amore efcient process. In an embodiment ofthe method according to the invention the step of forming a polymer- solvent gel further may comprise cooling the solvent during the formation ofthe polymer-solvent gel. An advantage ofthe abovementioned embodiment is that, due to the cooling, the formation of the polymer-solvent gel is accelerated. In an embodiment ofthe method according to the invention the biomass comprising polymer may originate from one or more ofthe sources selected from the group of organic residual waste, feedstock biomass or waste water. The abovementioned biomass sources have the advantage that they are readily available in sufcient quantities to provide a reliable and constant source of polymer for separation and processing. In addition, these sources are often considered relating to costs rather than as a resource having a (signicant) value. Thus, the biomass comprising (containing) polymer may be one or more selected rich in microorganisms and produced from the group oforganic sources including residual by-products or wastes, feedstock biomass or waste water derived from municipal, industrial or agricultural activities. In an embodiment ofthe method according to the invention the step of forming a polymer- solvent gel may comprise the step ofdissolving the polymer in a solvent. The method according to the invention comprises the dissolving the polymer in a solvent, which stepmay be provided by adding a solvent to the biomass. In another option, itmay be desired to, in a subsequent step, add additional solvent to at least partially dilute and / or rinse the polymer gel and / or cause any remaining polymer to become part of a polymer-solvent gel with preferred or desired properties. In an embodiment ofthe method according to the invention may further comprise the step of recirculating the solvent obtained after the step of melt processing the polymer-solvent gel to the step ofproviding a solvent to the biomass. An advantage ofrecirculating the solvent is that it reduces the cost associated with the method according to the invention and thus has a positive effect on the commercial viability of the manufacturing. This is mainly due to the fact that the costs associated with the solvent are high. The recirculation of the solvent thus signicantly reduces costs. Another advantage is that the recirculation (and re-use) of the solvent also reduces the environmental footprint of the method according to the invention. In addition, it was found that drying the polymer and recovering the solvent before the step ofextrusion was shown by the methods ofthe invention to not be necessary. In an embodiment ofthe method according to the invention the solventmay comprise one or more selected from the group of ketone, alcohol, hydrocarbon, aromatic hydrocarbon, carbonate ester. An advantage of the abovementioned solvents is that they provide a good balance between costs and effectivity with regard to the process steps described in the method according to the invention. In an embodiment ofthe method according to the invention, the solvent may be one ormore selected from the group ofacetone, methyl ethyl ketone, methyl isobutyl ketone, propanol, butanol, pentanol, hexanol, toluene, dimethyl carbonate, propylene carbonate. Preferably, the butanol is 2- butanol. The abovementioned solvents provide a good balance between temperature dependent solubility for the polymer and the ability to form a gel. An advantage of the abovementioned solvents is that they provide a good balance between costs and effectivity with regard to the process steps described in the method according to the invention. Another advantage of the abovementioned solvents is that they provide a good balance between dissolving and extracting the polymer from the biomass at an elevated temperature while tending to form a gel upon cooling the intermediate stage, being the polymer-solvent solution, after the polymer is dissolved. In anembodimentofthemethod according tothe invention, the solvent is amixture ofsolvents wherein due to the proportions ofthe mixture similarly provides a (good) balance between dissolving the polymer at elevated temperature and tending to form a gel upon cooling after the polymer is dissolved. In an embodiment ofthe method according to the invention, the methodmay further comprise the step ofproviding an additive to the solvent and / orpolymer-solvent gel. It is noted that the polymer and the solvent mixture just before the stage ofpolymer-solvent gel formationmay be referred to as a polymer-solvent solution. In a preferred embodiment, the additive may be one or more selected from the group of nucleators, plasticizers, composite materials, llers, antioxidants, colorants. In a further preferred embodiment, the additive is one or more selected from the group of a polymer, a polymer-solvent gel. An advantage of providing an additive is that predetermined thermal and / or mechanical properties can be provided to the polymer (or can be further enhanced). Another advantage is that an additive can be used to reduce the effects ofaging ofa product manufactured from the polymer. Furthermore, the addition ofadditives enables effective blending and achieving target quality and property specications ofthe extruded solid article. Yet another advantage of the step of providing an additive to the solvent, polymer-solvent solution, and / or polymer-solvent gel is that the additive can be effectively and homogenously blended with the polymer or in the gel in order to avoid a step ofmelt compounding. Avoiding a step ofmelt compounding reduces loss ofmolecular weight quality for the extruded article. Therefore, the method according to the invention enables the polymer quality to be controlled and conserved. In an embodiment ofthe method according to the invention, the methodmay further comprise the step of ltering the biomass after the step of dissolving the polymer in the solvent, such that suspended solids are separated from the solvent with dissolved polymer. Preferably, the step of ltering is performed before the step offorming a polymer-solvent gel. The suspended solids, such as suspended particulate parts of the biomass, are preferably removed from the polymer-solvent gel. An advantage ofusing a ltering step is that it provides an effective and cost-effective manner of at least partially removing suspended matter (such as the suspended particulate parts) from the gel. Preferably, the ltering is adapted to the type ofbiomass and / orthe type ofpolymer-solvent solution to provide optimal ltering results. Thismay forexample be the largest yield of gel and / or the highest purity of the gel (i.e. maximum removal of (undesired / unwanted) suspended solids that are considered as contaminants ofthe product purity or that detract in anyway from the nal article quality). It is noted that in this application ltering refers in general to methods of separation that effectively separate undesired particulate non-dissolved matter from a polymer solvent solution based on principles such as exclusion ofthe unwanted suspended solids due to particulate size or density before forming a gel. In an embodiment ofthe method according to the invention, the methodmay further comprise the step ofcontrolling the polymer-solvent gel formation. An advantage ofthe controlling step is thatthe specic process parameters ofthe gel formation may be adapted prior to and / or during the formation step to optimize the gel formation. The optimization may be provided with regard to the maximum gel formation (i.e. maximum polymer yield) and / or the quality ofthe polymer that is extracted and / or other suitable parameters, such as morphology. It is noted that the morphology can be controlled by the temperature of gelation, the rate of cooling ofthe polymer-solvent solution, and the degree ofmixing during cooling ofthe polymer- solvent solution and / or during gelation. In an embodiment ofthe method according to the invention, the methodmay further comprise the step ofcompressing the polymer-solvent gel. An advantage ofcompressing the polymer-solvent gel is thatpolymer (in terms ofweight) is controlled relative to the solvent (in terms ofweight). In other words, the polymer to solvent ratio is increased. Another advantage is that, by compressing the gel, an excess ofsolvent can be removed, for example for re-use, from the gel. This solvent removal may be advantageous for preparing the gel for the melt processing in the extruder. In other words, the step ofcompressing enables to lose (a surplus) of solvent. Therefore, the polymer to solvent ratio is improved. In an embodiment ofthe method according to the invention, the methodmay further comprise the step ofpressing residual solvent out ofthe polymer. An advantage ofthe pressing step of is that at least part ofthe solvent can be extracted for recirculation in an effective and (energy-)efcient manner. The pressing step may be performed in addition to other drying steps or methods, without limitation, to control the polymer (in terms of weight) relative to the solvent (in terms ofweights) before the step ofextrusion. Yet another advantage ofthe step of pressing residual solvent out of the polymer is that at least part ofthe mass ofundesired dissolved solids present in the solvent are removed from the gel by exuding at least some of the solvent from the gel. Preferably, including as part of the step of pressing, further rinsing ofthe gel with cleaner solvent is applied before the step ofextrusion. It is noted that pressing may comprise compressing. For example, the step of pressing may include applying normal or shear forces to the polymer-solvent gel that causes at least some solvent to be selectively removed while retainingmost ofthe polymermass contained in the polymer-solvent gel. In an embodiment ofthe method according to the invention, the methodmay further comprise the step of reducing the solvent in the solvent-polymer gel before and / or during the step of melt processing of the polymer-solvent gel, preferably the step of reducing the solvent-polymer gel comprises evaporation.An advantage of reducing the solvent in the solvent-polymer gel is that the amount ofsolvent in the polymer is reduced (even further). This for example allows the polymer to be solidied into at least one solid extrudate comprising at most 5 wt.% of solvent during and / or afterthe step ofproviding the polymer-solvent gel to an extruder. A further advantage of the step of reducing the solvent in the polymer-solvent gel before and / or during the step ofmelt processing ofthe polymer-solvent gel is that the morphology ofthe polymer-solvent gel can be controlled, preferably the morphology of the polymer-solvent gel is controlled before the step ofmelt processing ofthe polymer-solvent gel in the extruder. For example, the polymer-solvent gel morphology may be a gel granulate or gel paste. As a result, controlled feeding ofthe polymer-solvent gel to the extruder is achieved. In an embodiment ofthe method according to the invention, the methodmay further comprise the step ofgranulating the separated polymer and / or climatizing the separated polymer after the step ofmelt processing ofthe polymer-solvent gel in the extruder. It is noted that granulatingmay include pelletising. An advantage ofgranulating is that the one ormore solid extrudate may easily be transported and / or processed for further applications, such as the further steps of melt processing in manufacturing steps towards, for example, making nal consumer plastic articles. Furthermore, an advantage ofthe step ofclimatizing is that the one ormore solid extrudate is conditioned and stored appropriately. As a result, the one or more solid extrudate will not absorb water and / or volatile matter from the environment, and further processing using the granulate ofthe solid extrudate is possible without drying is enabled. An advantage ofavoiding water absorption is to reduce risk for decomposition ofthe polymers during further processing and producing, thereby, nal articles ofhigher and controlled quality. A further advantage of further processing without drying enabled is to avoid associated costs of a drying step and thereby produce processed articles more economically. In an embodiment according to the invention, molten extrudate is fed or injected directly into ancillary equipment to ultimately form moulded articles, lms, membranes, or coated articles that are optionally based on conventional methods ofmelt processing and / or coating. In an embodiment according to the invention, the temperature ofthe solvent during addition to the biomass is at least 3 °C, preferably at least 5 °C, more preferably at least 10 °C, mostpreferably at least 15 °C, higherthan the temperature ofthe biomass comprising the polymer. An advantage of an increased temperature ofthe solvent is that an enhanced and / or a more rapid dissolution ofthe polymer and formation ofthe gel is achieved. This provides amore effective and efcient process. In an embodiment, the step of melt processing the polymer-solvent gel in the extruder is performed at a temperature which is at least 5 °C, preferably at least 10 °C, more preferably at least 15 °C, lower than the melting temperature ofthe polymer. The invention also relates to a system for melt extrusion of a polymer gel, the system comprising: - an extruder that is congured for melt processing a polymer-solvent gel at a temperature of at least 40 °C, - a feeding unit which is operatively coupled with the extruder such that the feeding unit is congured for feeding a polymer-solvent gel to the extruder, - solvent removal means which are operatively coupled with the extruder such that solvent is removed from the extruder, and - a die which is operatively coupled with an outer end ofthe extruder and providing an extrudate, wherein the extrudate comprises a polymer. The system according to the invention has similar effects and advantages as the method according to the invention. The system is specically congured to perform the aforementioned method, preferably including one or more of the optional method steps. More specically, the embodiments described in relation to the method according to the invention may be applied, either alone or in any combination, in the system according to the invention. The solvent removal means may for example comprise a solvent recovery unit, which terms are used interchangeably throughout the application. In an embodiment ofthe system according to the invention, the system may further comprise a control unit or controller that is congured to at least control a processing temperature in the extruder, wherein the control unit is congured to, during use, substantially maintain the processing temperature in the extruder at a temperature set point, wherein the temperature set point is a temperature that is at least 3 °C, preferably at least 5 °C, more preferably at least 10 °C, most preferably at least 15 °C, below the melting temperature ofthe polymer to be manufactured. An advantage of the control unit is that it can be used to regulate the temperature in the extruder to achieve or maintain the processing temperature near a set point that is at least 3 °C, preferably at least 5 °C, more preferably at least 10 °C, most preferably at least 15 °C, below the melting temperature of the polymer to be manufactured. This achieves that the polymer manufactured using the system has well-maintained quality, in particular with regard to maintained molecular weight ofthe polymer in the polymer-solvent gel. In an embodiment ofthe system according to the invention, wherein the system comprises at least one temperature sensor that is congured to measure a processing temperature in the extruder, and wherein the control unit comprises a processor that is congured to: _ calculate a difference between the measured processing temperature and the temperature set point, and _ to control the extruder, preferably a heating installation thereof, to regulate the processing temperature towards the set point temperature. The control unit preferably comprises a processor that is used to receive (real-time) data ofa sensor in the extruder. This allows a precise and continuous monitoring and adaptation of the processing temperature toward the set point to achieve a high-quality polymer. In particular, the control unit is congured to ascertain that the processing temperature does not exceed a processing temperature limit that is a temperature that is 3 °C, preferably at least 5 °C, more preferably at least 10 °C, most preferably at least 15 °C, below the melting temperature of the polymer to be manufactured. In an embodiment of the system according to the invention, the control unit may further comprise a processor and an inputmodule that are connected to each other, wherein the inputmodule is congured to receive control commands and / or control information from an external source, wherein the processor is congured for processing the information from the input module. An advantage of an input module, which may be a user interface or an external database containing for example polymer information, is that the system can be used to manufacture a large variety of different polymers or polymer blends. The input module, which is connected to the processor, allows the process parameters, in particularthe set point temperature in the extruder to be set at the relevant value forthe polymer (blend) to be manufactured. In an embodiment ofthe system according to the invention, the system may further comprise an extraction unitwhich is operatively coupled with the feeding unit, wherein the extraction unit is congured for dissolving apolymer in a solvent to form the polymer-solvent gel. An advantage ofan extraction unit according to this embodiment is that the polymer can be extracted from the biomass in an efcient and cost-effective mannerby dissolving the polymer from the biomass into the solvent. This allows a polymer-solvent gel to be formed, which can be processed further in the subsequent steps ofthe extrusion system. In an embodiment ofthe system according to the invention, the system may further comprise recirculation means which are congured to recirculate solvent removed from the extruder to the extraction unit. An advantage of recirculating the solvent is that the manufacturing cost ofthe polymer are signicantly reduced. This is mainly due to the fact thatthe solvent is an expensive resource. Another advantage is that the application ofthe recirculations means decrease the environmental impact of the system. This is on the one hand due to the fact that a limited amount ofsolvent is needed and on the otherhand due to the fact that it reduces the amount oftransport of said solvent to the location. A further advantage to recirculating solvent as part ofthe system is that a step ofseparately drying the polymer before extrusion is avoided. This combination of drying within the system of extrusion to a nal article facilitates more efcient processing ofpolymer and solvent. In anembodimentofthe system according to the inventionthe extrudermay comprise multiple heating zones, preferably at least 4 heating zones, more preferably at least 6 heating zones, most preferably at least 8 heating zones. An advantage of multiple heating zones is that a more consistent heating is achieved, thus allowing an improved control over the extruder. Another advantage is that the polymer-solvent gel can more easily be brought up to and maintained at the desired temperature that is at least 3 °C, preferably at least 5 °C, more preferably at least 10 °C, most preferably at least 15 °C, below the melting temperature ofthe polymer separated by the melt processing. In an embodiment ofthe system according to the invention the solvent removal means may comprise avacuum pump and a condenser. An advantage of a vacuum pump and condenser is that it provides an effective manner to separate and extract the evaporated solvent from the polymer. The condenser in particular provides that the solvent is condensed for easy recirculation to other parts ofthe system in which it can be re- used. In an embodiment ofthe system according to the invention, the system may further comprise cooling means and / or temperature controlling means, preferably a cooling device, more preferably a cooling bath, even more preferably awater bath, that is operatively coupled with the die to provide the extrudate to the cooling device. An advantage ofcooling means (such as a cooling device), in particular a cooling bath and / or temperature controlling bath, is that the extruded polymer can be cooled down to form a solidied polymer in a controlled manner. The solidied polymer can be stored and / or used for further processing, including the manufacturing of (bio)plastic articles. In an embodiment ofthe system according to the invention, the system may further comprise a lament puller and / or a pelletizer or granulator. It is noted that said lament puller and / or a pelletizer or granulator may be referred to as ancillary equipment to manage the extrudate, when formulated plastic pellets formed from the polymer dene the solid article to be produced. An advantage of this embodiment is that the extruded polymer is prepared for further processing, such as the manufacture of plastic articles. In particular polymer granules, pellets or laments are widely used as basis for manufacturing plastic articles. Therefore, it is advantageous to provide a lament puller and / or a pelletizer or granulator. In an embodiment ofthe system according to the invention, the system may further comprise a drying unit that is congured to dry the extrudate. An advantage ofdrying the extrudate is that the polymer can be stored in a dry manner. This reduces storage weight and also prevents the transport ofsolvent. Ifthe prepared polymer is used for the manufacture ofproducts, it is also advantageous ifthe polymer is dried before further processing it to products. In an embodiment of the system according to the invention, the control unit is further congured to control one ormore of: _ the feeding unit, _ the solvent removal means; _ the extraction unit, _ the recirculation means; _ the cooling device, _ the drying unit, _ the lament unit, and / or _ the pelletizer. It is advantageous ifthe control unit is congured to control one, preferably more or all, components of the system according to the invention. This allows an integrated control over the system, therewith allowing polymer to be processed and manufactured under highly controlled circumstances. This improves the quality ofthe polymer even further. In an embodiment according to the invention, the temperature ofthe solvent during addition to the biomass is at least 5 °C, preferably at least 10 °C, more preferably at least 15 °C higher than the temperature ofthe biomass comprising the polymer. An advantage ofan increased temperature ofthe solvent is that an enhanced dissolution and / or a more rapid dissolution of the polymer is achieved. This provides a more effective and efcient process. The invention further relates to an extrudate comprising a polymer obtainable by the method according to the invention and / orthe system according to the invention. The polymer according to the invention has similar effects and advantages as the method and / or the system according to the invention. The embodiments described in relation to the method and / or the system according to the inventionmay be applied, either alone or in any combination, to the polymer according to the invention. Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which: Figure 1 shows a schematic view ofan example ofthe method according to the invention, Figure 2 shows a schematic view ofan example ofa system according to the invention, Figure 3 shows a schematic view of an example of an extruder that can be used in the system according to the invention, Figure 4 shows a schematic view ofan example ofa control unit according to the invention, Figure 5 shows results ofan experiment according to an example ofthe method according to the invention, in particular melt and crystallization trends for heating and cooling PHB samples (it 10 OC / min) with 0, 5 and 86 wt.% 2-butanol content. The double peak for meltingPHB (5 wt.% 2-butanol) may reect a heterogenous distribution ofbutanol in the gel, Figures 6A and 6B show results of an experiment according to an example of the method according to the invention, in particular melting ofPHAs as dried polymer and gels. (a) DSC heat ow showing endothermic melting peaks for the neat dried PHB and aPHBV with 34 wt. % 3HV (0 wt.% 2 butanol). (b) Average melt temperatures ofgels for the same PHB and a co- polymer blend ofPHBV as a function ofwt.% 2-butanol t to atwo segment line by least squares regression, Figures 7A and 7B show results of an experiment according to an example of the method according to the invention, in particular PHBV thermal decomposition with and without 2- butanol. (a) Trend of the polymer molecular weight (intrinsic viscosity) for incubation of the same PHBV at 160 (squares) versus 180 (circles) °C given dried (open symbols) versus the gel melted polymer in 2-butanol (lled symbols). (b) decomposition assessed with respect to the trend ofa scission number with results that decomposition rates were inuenced by temperature but were not inuenced by presence ofthe solvent, Figure 8 shows results ofan experiment according to the method according to the invention, in particular a DSC measurement of a neat PHA sample that was a co-polymer blend of poly(3- hydroxybutyrate-co-3-hydroxyvalerate) with 34 weight percent of the 3-hydroxyvalerate monomer. Measurement shows a heating ramp at 10 ° / min revealing an endothermic melting peak marked by the shaded area A. Percent values denoting temperatures representing from 1 to 99 percent of the melting enthalpy are shown. Corresponding temperatures for 5, 50 and 95 percent ofthe enthalpy are shown by example as Tmos, Tso, and Tm95. A melting temperature may be dened forthe purposes ofthis invention as the temperature corresponding to 95 percent ofthe melting enthalpy, and Figure 9 shows results ofan experiment according to the method according to the invention, in particular DSC measurements that were made for a series of samples of neat poly(3- hydroxybutyrate-co-3-hydroxyvalerate), orPHBV, samples. The polymer samples had different monomer contents over a range of weight percent of the 3-hydroxyvalerate (3HV) monomer. With reference to Figure 8, in heating the neatpolymer samples at 10 °C / min, values for Tm05, Tm50, and Tm95 corresponding to the melt enthalpy peak were estimated. The melt temperature is inuenced by the polymermonomer composition and / orblend composition. This inuence is shown in this example by average trend of Tos, Tmso, and Tm95 estimated as a function of3HV content ofthe PHBV. In an example ofmethod 1000 (gure 1) for separating apolymer from a biomass including melt extrusion ofapolymer gel as an embodiment ofthe invention, method 1000 comprises the steps ofproviding 1002 a biomass comprising apolymer and providing 1004 a solvent to the biomass and subsequently dissolving 1006 the polymer in the solvent. Method 1000 further comprises the step of forming 1008 a polymer-solvent gel and providing 1010 the polymer-solvent gel to an extruder. Method 1000 further comprises the step ofmelt processing 1012 ofthe polymer-solvent gel in the extruder at a temperature of at least 40 °C, such that at least 85 wt.% ofthe solvent present in the polymer-solvent gel is separated by evaporation from the polymer. Step 1012 ofmelt processing the polymer-solvent gel in the extruder is performed at a temperature which is at least 3 °C lower than the melting temperature ofthe polymer. Method 1000 further also comprises the step ofdrying 1014 the polymer during melt processing to form at least one solid extrudate comprising atmost 5 wt.% of solvent. Furthermore, method 1000 may comprise one ormore optional steps which can be performed independently from each other as part of method 1000 or which can be applied in different combinations to method 1000. In the example (see gure 1), several ofthe optional steps are shown and described, even though they do not have to be applied to method 1000. An optional step concems pre-heating 1016 the solvent before said solvent is provided to the biomass, which optional step is performed before step 1004. Additionally, or alternatively, method 1000 may comprise the step ofproviding 1022 an additive to the solvent and / or solvent-polymer gel. Step 1022may be performed during step 1004 ofproviding the solvent, yetmay also be additionally or altematively be performed during or before other steps, such as the step of forming 1008 a polymer-solvent gel. A further optional step is performed during the step of dissolving 1006 the polymer in the solvent and comprises heating 1018 the solvent and biomass. The step offorming 1008 a polymer- solvent gel optionally comprises cooling 1020 the solvent during the formation of the polymer- solvent gel.A further optional step, which is performed as part ofstep 1008 is the step ofcontrolling 1026 the polymer-solvent gel formation. Further optional steps thatmay be performed as part ofthe step offorming 1008 or thereafter, are the step ofltering 1024 the polymer-solvent gel, such that suspended solids are separated from the polymer-solvent gel, the step of compressing 1028 the polymer-solvent gel and / or the step of pressing 1030 residual solvent out ofthe polymer-solvent gel. A further optional step is the step of recirculating 1032 the solvent obtained after step 1012 to step of providing 1004 a solvent to the biomass. Further optionally, method 1000 comprises the step of granulating 1034 and / or the step of climatizing 1035 the separated (also referred to as extruded) polymer (after extrusion thereof). Also optionally, method 1000 further comprises the step of drying 1036 of the extruded polymer. This step can be performed before or after the step ofgranulating 1034 and / orthe step ofclimatizing 1035 the separated polymer. In an example ofsystem 2 in an embodiment according to the invention (see gure 2) formelt extrusion ofapolymer gel G, system 2 comprises extruder 4 that is congured for melt processing apolymer-solvent gel. To that end, extruder4 is providedwith inlet 6 forreceiving apolymer-solvent gel and outlets 8 and 10. Outlet 8 is solvent outlet 8 that is congured for discharging solvent S from extruder 4, whereas polymer outlet 10 is congured for discharging polymer P that is formed in extruder 4. Preferably, extruder 4 is congured to process a continuous ow ofpolymer-solvent gel. Extruder 4 further comprises inner space 12, which is operatively connected to inlet 6, solvent outlet 8 andpolymer outlet 10, and which is congured as processing space for processing polymer-solvent gel G. System 2 further comprises extrusion feeder 14 or feeder unit 14 (which terms are used interchangeably herein), which is operatively coupled to inlet 6 ofextruder 4 and which is congured to feed a predetermined amount ofpolymer-solvent gelG (over a predetermined amount oftime T) to extruder 4. In addition, system 2 comprises solvent removal means inthe form ofsolvent recovery unit 16, which is operatively coupled to solvent outlet 8, and extrusion die (not shown) which is operatively coupled to polymer outlet 10. The extrusion die is congured to extrude polymer from extruder 4 into a specic shape. System 2 in this example (see gures 2, 4) further also comprises controller 19, which is congured to control one ormore aspects ofsystem 2, including operational values and / or one ormore parts ofsystem 2. In amore detailed example (see gure 3), extruder 104 comprises extrusion barrel 120 having inlet 106 that is connected to extrusion feeder 114, which in this example is hopper 114. In this example, hopper 114 is operatively connected to extrusion feeder supply 122. Extruder 104 further comprises motor 124 that is usable to drive extrusion means, such as extrusion screws, (not shown) in extrusion barrel 120 and also comprises heating installation 126. In this particular example, extrusion barrel 120 comprises four heating zones 128, each of which is provided with heat by heating installation 126. Heating installation 126may comprise a single heating unit 130 or multiple heating units 130 that are coupled to, or in some cases provided in, one ormore heating zones 128 for extrusion barrel 120. In this example (see gure 3), solvent recovery unit 116 is formed byvacuum pump 132 and condenser 134, which are operatively coupled to solvent outlet 108 for extrusion barrel 120. In this example, extruder die 118 is coupled to polymer outlet 110 in longitudinal end 120a of extrusion barrel 120, from which polymer can be discharged, for example under pressure, out of inner space 112 (of extrusion barrel 120). This example (see gure 3) further shows optional cooling means (such as a cooling bath) 136 in which, during use, polymer P extruded through extruder die 118 can be cooled down, preferably cooled down in a controlled manner. In this example, polymer P is displayed as polymer lament F, which isdrawn through cooling means (such as a cooling bath) 136 by means oflament puller 138. Optional pelletizer 140 is shown to be positioned downstream of lament puller 138 to pelletize polymer lament F. Cooling means (such as a cooling bath) 136 is provided with cooling bath inlet 142 and cooling bath outlet 144, which allows a stable cooling temperature to be achieved in cooling means (such as a cooling bath) 136. It is noted that cooling means (such as a cooling bath) 136, lament puller 138 and pelletizer 140 all are optional parts of extruder 104 andmay be dispensed with. It is furthermore noted that other congurations ofextruder 104 are also possible and that the present example may be provided with different or other parts that perform a similar function. Preferably, the molten extrudate from die 118 may be processed further. In this example (see gure 4), controller 119 is also congured to control extruder 104. In particular, controller 119 is connected to hopper 114 to control the feed ofpolymer-solvent gel G that is fed into extruder barrel 120. It is further connected to heating installation 126 to control the amount of heat provided to the various heating zones 128, in this case by controlling the one or more heating units 130. Controller 119 in this example is also congured control solvent recovery unit 116, in particularvacuum pump 132, and to control water supply to and discharge from coolingmeans (such as a cooling bath) 136. Furthermore, controller 119 is in this example congured to control operational parameters oflament puller 138 and pelletizer 140, for example the rotation speed of lament puller 138 and / or the size ofpellets made by pelletizer 140. In use of extruder 104, as shown in this example (see gure 3, 4), polymer-solvent gel G is fed from extrusion feeder supply 122 into hopper 114 (controlled by controller 119) after which it enters into inner space 112 of extrusion barrel 120. Motor 124 (preferably controlled by controller 119) drives the extrusion means (preferably at a controlled rate) to process polymer-solvent gel G during its transport through heating zones 128. During transport, polymer P and solvent S are separated from each other out ofpolymer-solvent gel G. Solvent S is evaporated and discharged by vacuum pump 132 via conduit 133 to condenser 134, in which solvent S is condensed for re-use. Polymer P is extruded through extruder die 118 to form, in this example, a (solid) lament F that is subsequently pulled further downstream by lament puller 138 through cooling means (such as a cooling bath) 136 for cooling down (preferably in a controlled manner). Thereafter, it is pelletized by pelletizer 140 as preparation for further processing to make products comprising the polymer. During use, controller 119 controls one ormore parameters ofthe process, preferably in an integrated manner, to allow continuous processing ofpolymer-solvent gelG into polymer P with recovery of solvent S. In the example ofsystem 2 (see gure 2), system 2 further comprises components that allow the formation, extraction and processing ofthe polymer-solvent gel G. To that end, system 2 further comprises biomass feed 46 that is operatively coupled to extraction unit 48, which further comprises solvent inlet 50 to form a biomass-solvent mixture in inner space 52 ofextraction unit 48. Outlet 54 ofextraction unit 48 is operatively coupled to separatorapparatus 56, which is congured to separate suspended biomass solids BS from solvent PS in which polymer is dissolved. Separator apparatus 56 therefore is provided with biomass solids outlet 58 (for discharging suspended biomass solids BS) and outlet 60 for the polymer-solvent mixture. Outlet 60 is operatively connected to optional gelation apparatus 62, which may be used to promote gelation and formulation to obtain polymer- solvent gel G. In some cases, additional gelation is not required and the polymer-solvent mixture from outlet 60 is already sufciently gelated to be used as polymer-solvent gel G for polymer extrusion. In this example, gelation apparatus 62 is connected to outlet 60 for receiving the polymer- solvent mixture and is operatively connected, via conduit 64, to additive supply 66. The lattermay be used to provide additives to the mixture to improve and / or promote gelation and / or achieve formulation ofthe polymer-solvent gel G. In this example, processing unit 68 or processing units 68 are positioned downstream ofgelation apparatus 62. In this example, processing units 68 are one or more ofgel rinsing unit 68a, mechanical processing unit 68b, gel conditioning unit 68c and blending unit 68d. In general, processing unit(s) 68 is / are used at least for removing excess solvent from polymer-solvent gel G. Excess solventES is discharged from processing unit(s) via excess outlet 70 to solvent recycling unit 72. Optionally, one ormore ofprocessing unit(s) 68a, 68b, 68c, 68dmay be provided with solvent inlet 74, which is operatively connected to solvent supply 76, which in this example is a solvent supply for organic solvent S. It is noted that other solvents S may also be used in system 2. Solvent S may for example be used for gel rinsing or other processing steps to improve polymer-solvent gel G. Further optionally, one or more of processing unit(s) 68a, 68b, 68c, 68d may be provided with additive inlet 78, which is operatively connected to additive supply 66. Polymer-solvent gelG can be transported via gel outlet 80 of processing unit 68 and conduit 82 to extrusion feeder 14, 114, which is positioned upstream ofextruder 4, 104, and which is operatively connected to inlet 6, 106 of extruder 4, 104. Extruder 4, 104 is provided with solvent outlet 8, 108 that is congured for discharging solvent S from extruder 4, 104. The discharge of solvent S is achieved using solvent recovery unit 16, 116, which is operatively coupled to (or part of) extruder 4, 104. Solvent recovery unit 16, 116 is connected to solvent recycling unit 72, which in turn is operatively connected to solvent supply 76 or re-use of solvent S in system 2. Polymer outlet 10, 110 is congured for discharging polymer P that is formed by extruder die 118 in extruder 4, 104, for example using extruder die 118. Polymer outlet 10, 110 is operatively connected to polymer processing unit 84. Polymer processing unit 84 thatmay be polymer storage 84 ormay additionally or altematively be additional polymer forming apparatus 84, including but not limited to a moulding apparatus. Controller ofcontrol unit 19, 119 (see gure 4) in this example is also congured to control several other aspects of system 2, including one or more of (parameters of) biomass feed 46, extraction unit 48, additive supply 66, processing unit(s) 68, 68a, 68b, 68c, 68d, separator apparatus 56, gelation apparatus 62, solvent recycling unit 72 and solvent supply 76. To that end, in this example controller 19, 119 comprises processor 86 and optionally (operator) interface 88 and / or memory 90. Other computer- or processor-based components may also be usedwhen appropriate for the functioning ofsystem 2. In use ofsystem 2, polymer-containing biomass is provided viabiomass feed 46 to inner space 52 ofextraction unit 48. In addition, a predetermined amount ofsolvent is provided via solvent inlet 50 to inner space 52 of extraction unit 48. During extraction in extraction unit 48, polymer is dissolved in solvent S, thus extracting it from biomass B. Subsequently, the mixture of biomass, solvent and dissolved polymer is discharged via extraction unit outlet 54 to separator apparatus 56, in which (suspended) biomass solids are removed, for example using ltering or other suitable techniques, and discharged via biomass solids outlet 58. The remaining fraction of the mixture, which mainly comprises a mixture of solvent and dissolved polymer, is provided to gelation apparatus 62 via polymer-solvent mixture outlet 60 ofseparator apparatus 56. During processing of the solvent-polymer mixture in gelation apparatus 62, the solvent-polymer mixture is treated to form adesiredpolymer-solvent gel G. The processingmay include forexample the steps ofgelation and / or providing additives to create a polymer-solvent gel G with the desired properties. Several other optional steps may be applied after gelation, which include for example the steps of gel rinsing, blending, such as blending with other sources ofpolymer, mechanical processing such as pressing or compressing and / or conditioning. In particular, polymer-solvent gel G is processed to remove excess solvent ES, which is discharged towards solvent recycling unit 72 for re-use in solvent supply 76. The removal of excess solvent ES is preferably provided after any of the optional steps is performed, and in particular after other steps that include adding additional solvent such as gel rinsing. After the optional other processing steps, polymer-solvent gelG is provided, via gel outlet 80 and conduit 82 to extrusion feeder 14, 114 ofextruder 4, 104. Polymer-solvent gelG is processed in extruder 4, 104 to form polymer P extrudate, which is discharged via polymer outlet 10, and (reusable) solvent S that is discharged via solvent outlet 8. Solvent S is extracted using solvent recovery unit 16, 116 and is provided to solvent recycling unit 72 for reuse (via solvent supply 76) in system 2. Extruder 4, 104 is congured to melt process polymer-solvent gel G at a temperature of at least 40 °C and is controlled by controller 19, 119 to provide a melt process temperature that is at least 3 °C lower than the melting temperature of polymer P that is manufactured using system 2. This provides a high-quality polymer P. Several experiments were conducted in relation to the disclosure ofthe present application, of which some results are shown below. First, the melt and crystallizationtrends for heating and cooling PHB samples with different amounts ofsolvent (in wt.%) were researched. The results thereof are shown in gures 5 and 6. Subsequently, polymer degradation rates were evaluated with or without the presence of solvent (see gure 3 below). Parallel samples with and without added 2-butanol were heat treated by incubation in sealed tubes at 160 °C and 180 °C. A solvent mass was added to the polymer mass before heat treatment in order to target 66 wt.% 2-butanol. At the applied temperatures, in the presence of 2-butanol, PHA will melt to form viscous polymer solutions. The polymer decomposition rates were expressed as a scission number to compare the rate loss ofthe polymer intrinsic viscosity (average molecular weight). Constant decomposition rates were observed based on the linear trend of scission number with samples taken over 1 hour ofincubation. There was no statistically signicant inuence ofthe presence of2-butanol on the observed decomposition rates. Decomposition rates increased sixfold with atemperature increase from 160 °C to 180 °C (see gure 7). In further experiments, the melt processing ofa polymer-solvent gel was researched using an extruder in which the melt processing was executed (see Tables 1 and 2). Said results were achieved by the method according to the invention, in particular extruder operations for aPHBV gel granulate with 68 wt.% 2-butanol with 500 i 20 mm-Hg applied vacuum (SME = specic mechanical energy demand). Barrel zone 1 temperature setpointwas 25 °C. SME given on the basis ofoutput polymer, and output total productmass (polymer and solvent) in brackets. Table l: SME ofmelt processing using the method according to the invention Feeder gel Barrel screw rate and Die temperature and Mass output temperature Pressure EXtmda output rate SME g / h rpm °C °C bar % g / h kJ / kg 2-butanol _ _ _ Table 2: SME ofmelt processing using the method according to the invention Feeder gel Barrel screw rate and Die temperature and Mass output temperature Pressure EXtmda output rate SME g / h rpm °C °C bar % g / h kJ / kg 2-butanol From the experiments, it was found that the melt processing ofthe gel led to a consistent quality PHA along with concurrent solvent recovery. Production ofPHA, including both more amorphous PHBV and more crystalline PHB, was demonstrated through several extraction campaigns and subsequent polymer-solvent gel processing with variations in combinations with barrel and die temperature parameters. In a further experiment melting temperatures of dried (neat) polymers were quantied by differential scanning calorimetry (DSC). Differential scanning calorimetry (DSC 3+, Mettler- Toledo) was performed with nominally 2 to 5 mg ofthe polymer disposed to a tare weighed vented crucible. Crucibles were inserted to the DSC and held for 5 minutes at an initial temperature below the polymer glass transition temperature with nitrogen purge gas at 50mL min1 to obtain an initial stable heat ow signal. Thereafter, the crucible was heated at 10 °C min1 to melt the polymer and then it was cooled back down. From heating and cooling the endothermic melting (heating) and exothermic crystallization (cooling) peaks were respectively assessed. Endothermic melting peaks were not always single and well-dened over a narrow temperature range. Rather they often appeared as a broad distribution over a wide temperature range. The peaks were integrated, and the fractional area ofpolymer melting enthalpies were estimated as a function oftemperature. The end melt temperature of the (neat) polymer is dened for the purposes of this development as the temperature at 95 percent ofthe polymer melt enthalpy during heating at 10 °C min1 (Figure 8 and 9). Similarly, melting temperatures ofthe same polymers in polymer-solvent gels were measured byDSC measurements.A weighed sample mass from a gel was dispensed to a sealable tare weighed crucible. The masses of polymer and solvent in the gel sample were determined by published methods ofthermogravimetric analysis. Sealed crucibles were inserted to the DSC and held for 5 minutes at a start temperature below room temperature with nitrogen purge gas at 50mL minl. A set ofheating and quench cycles were applied by heating at 10 °C min1 to amaximum temperature above the melting point of the polymer in a gel, and cooling (quenching) back to the start temperature. The melting peak temperature range ofthe same polymer, in the form ofa solvent-gel, was generally observed to be lowerthan the melting temperature range for the neat polymer. Figure 8 shows a DSC measurement of a neat PHA sample that was a co-polymer blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with 34 weight percent of the 3-hydroxyvalerate monomer. Measurement shows a heating ramp at 10 °C minl revealing an endothermic melting peak markedbythe shaded areaA. Percentvalues denoting temperatures representing from 1 to 99 percent of the melting enthalpy are shown. Corresponding temperatures for 5, 50 and 95 percent of the enthalpy are shown by example as Tmos, Tmso, and ngs. An end melting temperature is dened for the purposes ofthis invention as the temperature corresponding to 95 percent ofthe melting enthalpy. Figure 9 shows DSC measurements that were made for a series of samples of neat poly(3- hydroxybutyrate-co-3-hydroxyvalerate), or PHBV, samples. The polymer samples had different monomer contents over a range ofweight percent ofthe 3-hydroxyvalerate (3HV) monomer. With reference to Figure 8, in heating the neat polymer samples at 10 °C minl, values for Tmos, Tmso, and ngs corresponding to the melt enthalpy peak were estimated. The end melt temperature ngs is inuenced by the polymer average monomer composition and / orblend composition. This inuence is shown in this example by the average trend lines ofTm05, Tmso, and Tm95 estimated as a function of 3HV content ofthe tested PHBV. The present invention is by no means limited to the above described preferred embodiments and / or experiments thereof. The rights sought are dened by the following claims within the scope ofwhichmany modications can be envisaged. CLAUSES 1. Method for separating apolymer from a biomass including melt extrusion ofa polymer gel comprising the steps of: providing a biomass comprising a polymer, providing a solvent to the biomass, dissolving the polymer in the solvent, forming a polymer-solvent gel, providing the polymer-solvent gel to an extruder, melt processing ofthe polymer-solvent gel in the extruder at a temperature ofat least 40 °C, such that at least 85 wt.% ofthe solvent present in the polymer-solvent gel is separated by evaporation from the polymer, and drying the polymer during melt processing to form at least one solid extrudate comprising at most 5 wt.% of solvent, wherein the step of melt processing the polymer-solvent gel in the extruder is performed at a temperature which is at least 3 °C lower than the melting temperature ofthe polymer. 2. Method according to clause 1, wherein the melt processing of the polymer-solvent gel is performed at a temperature in the range of40 °C to 200 °C, preferably in the range of50 °C to 160 °C. 3. Method according to any one of the preceding clauses, wherein the polymer-solvent gel comprises at most 95 wt.% solvent, preferably the polymer-solvent gel comprises solvent in the range of 5 wt.% to 95 wt.%, more preferably in the range of5 wt.% to 90 wt.%. 4. Method according to any one ofthe preceding clauses, wherein the polymer is one ormore polyhydroxyalkanoate. 5. Method according to the foregoing clause, wherein the polymer includes one or more monomer selected from the group of 3-hydroxybutyrate, 4-hydroxybutyrate, 3-hydroxyvalerate, 3- hydroxyhexanote, 3-hydroxyoctanoate, 3-hydroxydecanoate, 3-hyrodoxydodecanoate. 6. Method according to any one of the preceding clauses, wherein the step of providing a solvent to the biomass further comprises pre-heating the solvent before said solvent is provided to the biomass. 7. Method according to any one ofthe preceding clauses, wherein the step of dissolving the polymer in the solvent further comprises heating the solvent and biomass. 8. Method according to any one of the preceding clauses, wherein the step of forming a polymer-solvent gel further comprises cooling the polymer and the solvent during the formation of the polymer-solvent gel. 9. Method according to any one of the preceding clauses, wherein the biomass comprising polymer originates from one or more of the sources selected from the group of organic residual waste, feedstock biomass or wastewater. 10. Method according to any one of the preceding clauses, wherein the step of forming a polymer-solvent gel comprises the step ofdissolving the polymer in a solvent. 11. Method according to any one of the preceding clauses, further comprising the step of recirculating the solvent obtained after the step of melt processing the polymer-solvent gel to the step ofproviding a solvent to the biomass. 12. Method according to any one ofthe preceding clauses, wherein the solvent comprises one ormore selected from the group ofketone, alcohol, hydrocarbon, aromatic hydrocarbon, carbonate ester. 13. Method according to the foregoing clause, wherein the solvent is one ormore selected from the group of acetone, methyl ethyl ketone, methyl isobutyl ketone, propanol, butanol, pentanol, hexanol, toluene, dimethyl carbonate, propylene carbonate. 14. Method according to any one of the preceding clauses, further comprising the step of providing an additive to the solvent and / or polymer-solvent gel. 15. Method according to any one ofthe preceding clauses, furthercomprising the step ofltering the biomass after the step of dissolving the polymer in the solvent, such that suspended solids are separated from the solvent with dissolved polymer. 16. Method according to any one of the preceding clauses, further comprising the step of controlling the polymer-solvent gel formation. 17. Method according to any one of the preceding clauses, further comprising the step of compressing the polymer-solvent gel. 18. Method according to any one of the preceding clauses, further comprising the step of pressing residual solvent out ofthe polymer. 19. Method according to any one of the preceding clauses, further comprising the step of reducing the solvent in the polymer-solvent gel before and / or during the step ofmelt processing of the polymer-solvent gel, preferably the step of reducing the solvent in the polymer-solvent gel comprises evaporation ofthe solvent. 20. Method according to any one of the preceding clauses, further comprising the step of granulating the separated polymer and / or the step ofclimatizing the separated polymer after the step ofmelt processing ofthe polymer-solvent gel in the extruder. 21. Method according to any one ofthe preceding clauses, wherein the step ofmelt processing the polymer-solvent gel in the extruder is performed at a temperature which is at least 5 °C, preferably at least 10 °C, more preferably at least 15 °C, lowerthan the melting temperature ofthe polymer. 22. System formelt extrusion ofapolymer gel comprising: an extruder that is congured for melt processing a polymer-solvent gel at a temperature of at least 40 °C, a feeding unit which is operatively coupled with the extruder such that the feeding unit is congured for feeding a polymer-solvent gel to the extruder, solvent removal means which are operatively coupled with the extruder such that solvent is removed from the extruder, and a die which is operatively coupled with an outer end of the extruder and providing an extrudate, wherein the extrudate comprises a polymer. 23. System according to the foregoing clause, furthercomprising a control unitthat is congured to at least control a processing temperature in the extruder, wherein the control unit is congured to, during use, substantially maintain the processing temperature in the extruder at a temperature set point, wherein the temperature set point is a temperature that is at least 3 °C below the melting temperature ofthe polymer to be manufactured. 24. System according to clause 22 or 23, further comprising an extraction unit which is operatively coupled with the feeding unit, wherein the extraction unit is congured for dissolving a polymer in a solvent to form the polymer-solvent gel. 25. System according to the foregoing clause, further comprising recirculation means which are congured to recirculate solvent removed from the extruder to the extraction unit. 26. System according to any one ofthe clauses 22 to 25, Wherein the extruder comprises multiple heating zones, preferably at least 4 heating zones, more preferably at least 6 heating zones, most preferably at least 8 heating zones. 27. System according to any one of the clauses 22 to 26, Wherein the solvent removal means comprise avacuum pump and a condenser. 28. Extrudate comprising a polymer obtainable by the method according to any one of the clauses 1 to 21 and / orthe system according to any one ofthe clauses 22 to 27. 29. Use ofapolymer according to clause 28 in the manufacturing ofa plastic article.

Claims

1. Method for separating a polymer from a biomass-containing melt extrusion of a polymer gel comprising the steps of: the provision of a biomass comprising a polymer; providing a solvent to the biomass; dissolving the polymer in the solvent; the formation of a polymer-solvent gel; supplying the polymer-solvent gel to an extruder; the melt processing of the polymer-solvent gel in the extruder at a temperature of at least 40 °C; such that at least 85 wt.% of the solvent present is separated in the polymer-solvent gel by means of evaporation of the polymer; and drying the polymer during melt processing to obtain at least a solid extrudate comprising a maximum of 5 wt.% solvent to form where the step of melt processing the polymer-solvent gel in the extruder is carried out at a temperature that is at least 3 °C lower than the melting temperature of the polymer.

2. Method according to claim 1; involving the melt processing of the polymer solvent gel is performed at a temperature in the range of 40 °C up to and including 200 °C; preferably in the range of 50 °C up to and including 160 °C.

3. Method in accordance with one of the preceding claims; whereby the polymer solvent applies contains the highest 95 wt.% solvent; preferably the polymer solvent includes gel solvent in the range of 5 wt.% up to and including 95 wt.%; preferably in the range of 5 wt.% up to and including 90 wt.%.

4. Method in accordance with one of the preceding claims; whereby the polymer one or more is polyhydroxyalkanoate.

5. Method according to the preceding claim; where the polymer is one or more monomers contains selected from the group of 3-hydroxybutyrate; 4-hydroxybutyrate; 3-hydroxyvalerate; 3- hydroxyhexanut; 3-hydroxyoctanoate; 3-hydroxydecanoate; 3-hyrodoxydodecanoate.

6. Method in accordance with one of the preceding claims; whereby the step of providing a solvent to the biomass further preheating of the solvent involves before it solvent is supplied to the biomass.

7. Method according to one of the preceding conclusions; where the step of solving the polymer in the solvent further heating of the solvent and the biomass involves.

8. Method in accordance with one of the preceding conclusions; whereby the step of forming a polymer-solvent gel further cooling of the polymer and the solvent involves during the formation of the polymer-solvent gel.

9. Method in accordance with one of the preceding claims; whereby the biomass comprising polymer that a <omstig is van een ofmeervan de bronnen geselecteerd uit de groep van organisch residual waste; raw material biomass or wastewater.

10. Method in accordance with one of the preceding conclusions; whereby the step of forming a Polymer-solvent gel comprises the step of dissolving the polymer in a solvent.

11. Method in accordance with one of the preceding claims; further comprising the step of the recirculation of the solvent obtained after the step of melting and processing the polymer solvent gel to the step of providing a solvent to the biomass.

12. Method in accordance with one of the preceding claims; where the solvent one or more includes selected from the group of ketone; alcohol; alcohol; hydrocarbon; aromatic hydrocarbon; carbonate ester.

13. Method in accordance with the preceding claim; where the solvent is one or more selected from the group of acetone; methyl ethyl ketone; methyl isobutyl ketone; propanol; butanol; pentanol; hexanol; toluene; dimethyl carbonate; propylene carbonate.

14. Method in accordance with one of the preceding claims; further comprising the step of the providing an additive to the solvent and / or the polymer solvent gel.

15. Method in accordance with one of the preceding claims; further comprising the step of the filtering of the biomass the step of dissolving the polymer in the solvent; such that that suspended solids are separated from the solvent with dissolved polymer.

16. Method in accordance with one of the preceding claims; further comprising the step of the controlling the polymer-solvent gel formation.

17. Method in accordance with one of the preceding claims; further comprising the step of the compressing the polymer-solvent gel.

18. Method in accordance with one of the preceding claims; further comprising the step of the Squeezing out residual solvent in the polymer.

19. Method in accordance with one of the preceding claims; further comprising the step of the reducing the solvent in the polymer-solvent gel before and / or during the step of the melt processing of the polymer-solvent gel; preferably the step of reducing the The solvent in the polymer-solvent gel involves evaporation of the solvent.

20. Method in accordance with one of the preceding claims; further comprising the step of the granulation of the separated polymer and / or the step of climate control of the separated polymer after the melting step, processing of the polymer-solvent gel in the extruder.

21. Method in accordance with one of the preceding claims; whereby the step of processing the melt of the polymer-solvent gel in the extruder is carried out at a temperature that is at least 5 preferably at least 10 °C; by more preference at least 15 °C; is lower than the melt temperature of the polymer.

22. System for melt extrusion of a polymer gel comprising: an extruder designed for the melt processing of a polymer-solvent gel at a temperature of at least 40 °C; a feeding unit that is operationally connected to the extruder such that the The supply unit is designed for supplying a polymer solvent gel to the extruder; solvent removal agents that are active connected to the extruder in such a way that solvent is removed from the extruder; and one that is operational connected to an outer end of the extruder and the supplying an extrudate; where the extrudate comprises a polymer.

23. System in accordance with the preceding claim; further comprising a control unit which is designed to control at least one processing temperature in the extruder; whereby the The control unit is configured to; during operation; primarily the processing temperature in the to maintain the extruder at a set temperature; where the set temperature is temperature is at least 3 °C lower than the melting temperature of the polymer to be manufactured is.

24. System within the meaning of claim 22 or 23; further comprising an extraction unit operating is connected to the feed unit; where the extraction unit is configured for dissolving a polymer in a solvent to form a polymer-solvent gel.

25. System in accordance with the preceding claim; further comprising recirculating means which are designed to recirculate solvent removed from the extruder to the extraction unit.

26. System according to one of claims 22 to 25; where the extruder a multiple of comprises heating zones; preferably at least 4 heating zones; more preferably at at least 6 heating zones; most preferably at least 8 heating zones.

27. System according to one of Claims 22 to 26; where the solvent removal equipment includes a vacuum pump and a condenser.

28. Extrudate comprising a polymer obtainable by the method according to one of the claims 1 to 21 and / or the system under one of claims 22 to 27.

29. Use of a polymer pursuant to claim 28 in the manufacture of a plastic article.

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