Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/62—Carboxylic acid esters
  • C12P7/625—Polyesters of hydroxy carboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M23/00—Constructional details, e.g. recesses, hinges
  • C12M23/58—Reaction vessels connected in series or in parallel
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M45/00—Means for pre-treatment of biological substances
  • C12M45/04—Phase separators; Separation of non fermentable material; Fractionation
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M45/00—Means for pre-treatment of biological substances
  • C12M45/20—Heating; Cooling
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M47/00—Means for after-treatment of the produced biomass or of the fermentation or metabolic products, e.g. storage of biomass
  • C12M47/10—Separation or concentration of fermentation products
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P39/00—Processes involving microorganisms of different genera in the same process, simultaneously
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/40—Preparation of oxygen-containing organic compounds containing a carboxyl group including Peroxycarboxylic acids
  • C12P7/52—Propionic acid; Butyric acids
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/40—Preparation of oxygen-containing organic compounds containing a carboxyl group including Peroxycarboxylic acids
  • C12P7/54—Acetic acid
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
  • C10B53/02—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form of cellulose-containing material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L9/00—Treating solid fuels to improve their combustion
  • C10L9/08—Treating solid fuels to improve their combustion by heat treatments, e.g. calcining
  • C10L9/086—Hydrothermal carbonization
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E50/00—Technologies for the production of fuel of non-fossil origin
  • Y02E50/10—Biofuels, e.g. bio-diesel

Definitions

• This invention relates to a method and a plant for the conversion of mainly cellulosic material.
• This invention is thus applied in particular in the chain of recycling, and in particular in the exploiting of the waste of the printing or offset printing industry.
• the prior art includes some methods allowing recovery of cellulosic waste and transforming it in substances of wide consumption and use, such as for example methane gas, other types of fuels or in recycled paper.
• US publication US2012/0073199 described a bio-treatment able to transform wood-cellulosic materials into methane or ethanol.
• the process described therein consists of a succession of steps, which consists mainly in a first step of pyrolysis at low temperature and of long duration ⁇ Long Time-Low Temperature) followed by an anaerobic bio- treatment of digestion, or of fermentation with low oxygen content.
• the process illustrated in US2012/0073199 comprises inlet of the pyrolysis liquids (and preferably also of the pyro- gas) in an anaerobic fermenter, for obtaining ethanol, or in an anaerobic digester, for obtaining biogas (methane).
• the described process can disadvantageously develop only a portion of the methane potential of the material, which makes it relatively not easily applicable and economically disadvantageous.
• An aim of the present invention is therefore to provide a method and a plant for the conversion of mainly cellulosic material, or for waste from the industry of the paper/offset printing, able to overcome the drawbacks of the prior art.
• the aim of this invention is to provide a method and a plant for the conversion of mainly cellulosic material that is rapid and efficient. Further, an aim of this invention is to provide a method and a plant for the conversion of mainly cellulosic material able to produce bioplastic.
• the aims are achieved by a method for the conversion of mainly cellulosic material according to or more of the claims from 1 to 13 and by a plant for the conversion of mainly cellulosic material according to or more of claims from 14 to 25.
• the aims are achieved by a method comprising steps of:
• thermochemical treatment - predisposing a mixed aerobic bacterial population; - decomposition of said quantity of mainly cellulosic material into a liquid fraction, a gaseous fraction and a solid fraction by means of a predetermined thermochemical treatment;
• This method is preferably actuated by a plant, also according to this invention, comprising:
• - heating means provided with at least a chamber and designed to superheat the material contained in said chamber so as to break it down into a liquid fraction, a gaseous fraction and a solid fraction; said chamber being provided with at least an infeed, for allowing entry of a predetermined quantity of mainly cellulosic material, and at least an outfeed, for allowing said liquid fraction and said gaseous fraction to exit the chamber; - an anaerobic digester or fermenter operatively positioned downstream of said heating means, set up to receive said liquid fraction and gaseous fraction and designed to convert the fractions into a solution containing volatile fatty acids by means of the action of an anaerobic bacterial population;
• a first aerobic reactor operatively positioned downstream of said anaerobic digester, set up to receive a first portion of said solution and designed to convert it, by means of the action of a mixed aerobic bacterial population, into a bacterial population enriched with polyhydroxyalkanoates;
• a second aerobic reactor provided with at least a first infeed and a second infeed respectively predisposed to receive a second portion of solution from said anaerobic digester and the enriched bacterial population from said first aerobic reactor; said second aerobic reactor being configured so as to make said second portion of the solution react with said enriched bacterial population for obtaining products rich in polyhydroxyalkanoates;
• - separating means located operatively downstream of said second aerobic reactor and configured so as to split said products into a useful fraction, defined mainly by polyhydroxyalkanoates, and a residual fraction, defined mainly by a cellular residue.
• - figure 1 schematically illustrates a plant for the conversion of mainly cellulosic material according to the invention, in a first embodiment thereof
• - figure 2 schematically illustrates a plant for the conversion of mainly cellulosic material according to the invention, in a second embodiment thereof;
• FIG. 3 schematically illustrates a plant for the conversion of mainly cellulosic material according to the invention, in a third embodiment thereof;
• figure 4 is a detail of figure 3.
• reference numeral 100 denotes a plant for recycling of mainly cellulosic material according to the invention, which plant 100 is preferably designed for implementing the conversion method of mainly cellulosic material, also described in the following and object of the present invention.
• mainly cellulosic material is intended to define those materials wherein the percentage of lignin is very much lower than that of the cellulose, such as for example paper or cardboard.
• wood is also to be considered a mainly cellulosic material (it is composed of cellulose up to approximately 40-50%), it has a high lignin content (25-30%), which makes not ideally suitable for the treatment using the method and plant according to the present invention.
• mainly cellulosic material will hereinafter be used, preferably, for those materials having a cellulosic content of above 40% and a lignin content of less than 20% (more preferably less than 15%, such as for example waste in the printing or offset printing industry.
• mainly cellulosic material is used in this text to define a material with high cellulosic content (greater than 40%) and a carbon/nitrogen ratio of greater than 50 (C/N>50).
• the method according to the present invention thus entails predisposing a predetermined quantity 1 of mainly cellulosic material to be treated.
• This quantity may be defined and discrete, or fed continuously to the plant 100.
• the flow rate of mainly cellulosic material is preferably between 3000 and 5000 tonnes/year, more preferably approximately 4000 tonnes/year.
• the method according to this invention comprises subjecting the quantity 1 of material to a succession of steps consisting mainly of a thermochemical treatment, followed by a fermentation or anaerobic digestion and by an aerobic digestion so as to obtain a production of polyhydroxyalkanoates (PHA), or of bioplastic.
• a thermochemical treatment consisting mainly of a thermochemical treatment
• a fermentation or anaerobic digestion followed by an aerobic digestion so as to obtain a production of polyhydroxyalkanoates (PHA), or of bioplastic.
• PHA polyhydroxyalkanoates
• the method comprises a first step of decomposition of the quantity 1 of mainly cellulosic material into a liquid fraction 1 a, a gaseous fraction 1 b and a solid fraction 1 c.
• the liquid fraction 1 a is defined as bio-oil (or tar); the gaseous fraction 1 b is known as syngas and the solid fraction is known as b o-char.
• the liquid fraction 1 a comprises substances such as for example acetic aid, propionic acid, hydroxy acetaldehyde, hydroxy acetic acid, oligosaccharides, methanol, phenols.
• the gaseous fraction 1 b on the other hand comprises portions of methane, carbon monoxide, carbon dioxide, hydrogen and other gaseous substances.
• the solid portion 1 c is instead mainly defined by a carbon-rich residue (char) with a certain ash content.
• This decomposition is performed using a predetermined thermochemical treatment.
• the step of decomposition is defined by a overheating of the quantity 1 of mainly cellulosic material performed to a preset temperature for a predetermined interval of time.
• thermochemical treatment is preferably carried out by superheating the quantity 1 of mainly cellulosic material in a high temperature environment, between 350 and 800 °C, preferably between 400° and 500°C.
• thermochemical treatment is preferably defined by one of the following processes:
• the pyrolysis is performed at high temperature and with a brief duration.
• the liquid fraction 1 a is defined as pyrolysis oil (or tar);
• the gaseous fraction 1 b is known as syngas and the solid fraction is known as b o-char.
• the pyrolysis is performed by superheating the quantity 1 of material to a temperature of between 400° C and 550° C, preferably using the action of a current of inert gas (nitrogen, carbon dioxide or super-heated water vapour).
• inert gas nitrogen, carbon dioxide or super-heated water vapour
• this treatment is performed at a temperature of between 650° C and 800° C and in the presence of a reactive gas (carbon dioxide, super-heated water vapour, oxygen or air in reduced quantity relative to the stoichiometry of combustion).
• a reactive gas carbon dioxide, super-heated water vapour, oxygen or air in reduced quantity relative to the stoichiometry of combustion.
• this process advantageously enables reducing the energetic requirements, and reducing the production of char, increasing the efficiency of the process.
• this treatment is performed at a temperature of between 250° C and 400° C.
• the hydrothermal liquefaction does not comprise the passage of state (volatilization) of the products, and may thus be performed on a moist or watery substrate (having a water content of up to
• the plant 100 is equipped with heating means 1 1 provided with at least a chamber 16 for containing the quantity 1 of material to be broken down.
• the heating means 1 1 are thus configured for superheating the material 1 contained in the chamber 16 with the aim of decomposing it into the liquid fraction 1 a, the gaseous fraction 1 b and the solid fraction 1 c.
• the chamber 16 is thus provided with at least an inlet 16a, designed to allow access of the predetermined quantity 1 of mainly cellulosic material, and of at least an outlet 16b, designed to allow the release of the liquid fraction 1 a and the gaseous fraction 1 b.
• the chamber 16 preferably also comprises a second outlet 16c designed to enable exit of the solid fraction 1 c.
• the heating means 1 1 preferably comprise a pyrolyser 29 or a gasifier.
• the pyrolyser 29 is preferably configured for superheating the chamber 16 (by action of an inert gas, previously super-heated, or using another carrier) to a temperature of between 350° C and 800° C, preferably between 400° C and 600° C, even more preferably between 400° C and
• the gasifier is configured so as to perform the decomposition of the quantity 1 of material at high temperatures, higher than 650° C, in the presence of a gasifying action (carbon dioxide, water vapour, oxygen or air in sub-stoichiometric quantities).
• a gasifying action carbon dioxide, water vapour, oxygen or air in sub-stoichiometric quantities.
• the quantity 1 of mainly cellulosic material is broken down into three distinct fractions 1 a, 1 b, 1 c.
• liquid fraction 1 a and gaseous fraction 1 b are then subjected to a fermentation inside a fermenter (or digester) 12.
• This fermentation is performed by introduction of the liquid fraction 1 a and gaseous fraction 1 b into an anaerobic environment (at very low or zero quantity of oxygen) and inoculated with an anaerobic bacterial population 2.
• the plant 100 comprises an anaerobic digester 12 or fermenter operatively positioned downstream of the heating means 1 1 , predisposed for receiving the liquid fraction 1 a and gaseous fraction 1 b. Consequently, the anaerobic digester 12 has an inlet 12a in fluid connection with the first outlet 16b of the chamber 16.
• the anaerobic digester 12 is configured for converting the liquid fraction 1 a and gaseous fraction 1 b into the VFA solution containing volatile fatty acids by the action of an anaerobic bacterial population 2.
• the anaerobic bacterial population 2 is designed, in anaerobic conditions, such as to convert the liquid fraction 1 a and gaseous fraction 1 b into a VFA solution containing volatile fatty acids.
• volatile fatty acids is taken to define those acids having a carbon-rich skeleton with a number of less than six.
• These acids are for example acetic acid, propionic acid and butyric acid. Therefore the VFA solution obtained with the fermentation step defines a substrate rich in these acids.
• the anaerobic bacterial population 2 is preferably accumulated in a specific medium and is defined by the capacity thereof of converting the pyrolysis gas (gaseous fraction 1 b) and the pyrolysis liquid (liquid fraction 1 a) in a solution 4 enriched with volatile fatty acids (VFA).
• the digester 12 is added to by a predetermined quantity of solid fraction 1 c (or of vegetable carbon otherwise obtained).
• the anaerobic digester 12 is in connection (functional and structural) with the second outlet 16c of the chamber 16.
• the method also comprises a mixing step performed operatively upstream of the fermentation step, wherein the gaseous fraction 1 b is struck by a nebulized portion 2a of the anaerobic bacterial population 2.
• the mixing also preferably occurs by Venturi effect.
• the plant 100 preferably comprises an absorption column 17 operatively interposed between the heating means 1 1 and the anaerobic digester 12.
• nebulized portion 2a is aspirated from the digester 12 by special means.
• the absorption column 17 is equipped with suction means 17a
• a hydraulic pump for aspirating a portion 2a of the anaerobic bacterial population 2 from the anaerobic digester 12, striking at least the portion gaseous fraction 1 b with this nebulized portion 2a.
• This also enables speeding up the action of the subsequent anaerobic digester 12, allowing a continuous operation of the plant (that is, a continuous carrying out of the method).
• the absorption column 17 preferably comprises at least a Venturi tube 17b
• the absorption column 17 is defined by a Venturi Scrubber. Therefore, the absorption column comprises the Venturi tube 17b, into which the gaseous fraction 1 b and the nebulized portion 2a of the anaerobic bacterial population 2 are introduced, and a filling column (not illustrated), in which the gaseous fraction 1 b, when rising along the column, is freed from a liquid part, which goes to mix with the liquid fraction 1 a in inlet to the anaerobic digester 12.
• the gaseous fraction 1 b is introduced together with the nebulized portion 2a through the Venturi tube 17b; in proximity of the choke in the pipe 17b there is a reduction in cross-section of the pipe and therefore an increase of the speed through it; this increase of the speed generates load losses in the flow, which generate turbulences that are aimed at facilitating the absorption action of the nebulized portion 2a.
• the anaerobic digester 12 thus provides, at a relative outlet 12b, the VFA solution containing volatile fatty acids, defining a substrate for the subsequent steps of the method.
• a device selector 32 is provided operatively downstream of the digester 12, which selector 32 is configured for decomposing the VFA solution in such a way as to separate the compounds of interest (the volatile fatty acids VFA proper) from other compounds of the solution, such as for example anhydro sugars, sugars, phenols or primary products of cellulose pyrolysis.
• This device is preferably a pertraction device 32a.
• this device comprises a first 33 and a successive second stage 34.
• the VFA solution is mixed with a non-water-soluble dilutant (biodiesel, diesel oil, vegetable oil) and a non-soluble amine.
• a non-water-soluble dilutant biodiesel, diesel oil, vegetable oil
• the presence of the amine is such that the VFAs separate from the other compounds, solubilising in the non-water-soluble dilutant.
• This step is preferably, performed in a CSTR reactor 33a in order to maximise the effect.
• a sedimenter 33b is located where the aqueous phase (containing anhydro sugars, sugars and phenols), is separated from the non-water-soluble dilutant (containing the salt formed by amine and the VFAs)
• the aqueous phase is reintroduced upstream of the digester 12 and the mixture formed by the non-hydrosoluble dilutant, amine and VFA enters the second stage 34.
• the alkalinity of the liquid solution 5b is such that the VFA acids separate from the oil and combine with the liquid solution 5b.
• the step implemented by the device 32 is a step of pertraction, performed in two stages of mixing, sedimentation and successive separation (as already described in the foregoing).
• VFA solution will be termed in the same way both in a case where it has crossed the selector device 32 and in embodiments where the device is not present.
• the method comprises dividing the VFA solution into a first portion (VFA a ) and a second portion (VFA b ).
• this sub-division occurs downstream of the digester 12, which therefore has single outlet 12b.
• the division occurs internally of the digester 12, which therefore has an outlet 12b and a further outlet 12c.
• the flow of volatile acids dissolved in the first portion (VFA a ) is preferably comprised between 100 and 140 kg/h, more preferably about 120 kg/h.
• the flow rate of acids volatile dissolved in the second portion (VFA b ) is between 120 and 170 kg/h, more preferably approximately 150 kg/h.
• the first portion (VFA a ) is subjected to a respective step of aerobic digestion, performed by the action of a mixed aerobic bacterial population 3, with the aim of producing an enriched bacterial population 4 of polyhydroxyalkanoates (PHA).
• a respective step of aerobic digestion performed by the action of a mixed aerobic bacterial population 3, with the aim of producing an enriched bacterial population 4 of polyhydroxyalkanoates (PHA).
• the mixed aerobic bacterial population 3 is preferably accumulated in a specific terrain and is defined by a set of aerobic micro-organisms able to convert the VFA solution obtained starting from the fermentation of the liquid fraction 1 a and gaseous fraction 1 b.
• the mixed anaerobic bacterial population 3 comprise mixed bacterial cultures, for example bacteria of the following phyla: Proteobacteria, Bacteroidetes, Firmucutes and Actinobacteria.
• polyhydroxyalkanoate-enriched bacterial population is used to define, with no distinction: - a bacterial colony having a high polyhydroxyalkanoate content, or
• the enriched bacterial population 4 comprises a plurality of micro-organisms suitable for production polyhydroxyalkanoates (PHA).
• the plant 100 comprises at least a first aerobic reactor 13, operatively located downstream of the anaerobic digester 12 (associated to the outlet 12b).
• This first aerobic reactor 13 is predisposed to receive the first portion
• VFA a of the VFA solution and is configured to convert it, by the action of the mixed aerobic bacterial population 3, into the enriched bacterial population 4 of polyhydroxyalkanoates.
• the enriched bacterial population 4, in outlet from the first aerobic digester 13, is preferably composed of a moist part (sludge) and a dry part.
• the moist part has a flow rate of between 0.5 and 1 .5 m 3 /h, preferably approximately 1 m 3 /h.
• the dry part on the other hand, has a flow rate of between 40 and 60 kg/h, preferably approximately 50 kg/h.
• the aerobic reaction for obtaining the enriched bacterial population 4 is made according to the feast & famine principle.
• this enriched bacterial population 4 is achieved by a precise separation into two sub-steps, temporal or spatial, of the step of aerobic digestion of the first portion (VFA a ), and in particular into:
• the plant 100 can be realised in at least two substantially equivalent embodiments, one with "time separation” and the other with “spatial separation", which differ simply for the fact that the second step in one case is temporally distinct with respect to the first and in the other is spatially distinct in relation to the first.
• the step of aerobic digestion of the first portion (VFA a ) of the VFA solution is sub- divided into:
• first and the second periods are repeated cyclically in succession.
• the first aerobic reactor 13 preferably comprises at least a continuous flow stirred-tank reactor (CSTR) 27.
• CSTR continuous flow stirred-tank reactor
• This reactor is constituted by a tank 27a supplied by a flow of material (VFA solution and mixed aerobic bacterial population 3) and equipped with a stirring system 27b.
• This type of reactor advantageously enables an excellent mixing of the substrate, which is therefore homogeneous.
• the plant 100 preferably comprises feed means 18 associated with said first aerobic reactor 13 and designed to supply it with said first portion (VFA a ) of the VFA solution intermittently, at predetermined time intervals.
• the plant 100 comprises at least an anaerobic storage tank 19 located downstream of the anaerobic digester 12.
• the storage tank 19 is equipped with an inlet 19c connected to the anaerobic digester 12 (that is to the outlet 12b) and at least a first outlet 19a connected to the first aerobic reactor 13.
• the feed means 18 are therefore associated to this first outlet 19a.
• this digestion is sub-divided into: - a sub-step of introducing the first portion (VFA a ) of VFA solution into a first aerobic space (13a), having a predetermined size, containing the mixed aerobic bacterial population 3;
• PHA polyhydroxyalkanoates
• the second space 13b is positioned in succession to the first space 13a.
• the step of aerobic digestion of the first portion (VFA a ) of the VFA solution is also temporally continuous, avoiding the need for introducing storage tanks to interrupt the feeding of substrate to the first reactor 13.
• the first aerobic reactor 13 is preferably of the plug- flow type, which comprises at least a piston flow reactor (PFR) 26.
• the biochemical reaction i.e. the conversion of the first portion (VFAa) of the VFA solution into the enriched bacterial population 4) occurs inside the reactor and the concentration of products increases, and then decreases, with the spatial variable.
• the single piston flow reactor (PFR) 26 could be substituted by a plurality of continuous flow stirred-tank reactors (CSTR) located in series.
• CSTR continuous flow stirred-tank reactors
• the step of aerobic digestion of the first portion (VFA a ) is stabilised by addition of inorganic nutrient products 7.
• inorganic nutrient products is intended to define one or more of the following substances:
• the plant 100 preferably comprises at least a tank 21 (hopper) containing these inorganic nutrient products 7 and configured for providing the products 7 to the first aerobic reactor 13 for increasing the stability of the reaction.
• the plant 100 could be equipped with as many tanks as there are nutrients or with a single tank containing all the nutrients used.
• the tank 21 is preferably operatively connected to the heating means 1 1 so as at least in part to receive the solid fraction 1 c of the quantity 1 of mainly cellulosic material.
• the solid fraction 1 c of the quantity 1 of prevalently cellulosic material obtained following the decomposition step is rich in some inorganic nutrients 7.
• the method preferably also comprises a step of accumulating at least a part of the solid fraction 1 c of the quantity 1 of mainly cellulosic material in outlet from the heating means 1 1 .
• This accumulated part is stored in the tank 21 or directly inoculated inside the first aerobic reactor 13 with the function of a nutrient.
• the method includes a (further) step of aerobic digestion of a second portion (VFAb) of the VFA solution carried out by the action of the enriched bacterial population 4 for obtaining products 5 rich in polyhydroxyalkanoates.
• VFAb second portion of the VFA solution
• the step of aerobic digestion of the second portion is a step of accumulating polyhydroxyalkanoates (PHA).
• This (further) step of aerobic digestion is preferably performed in a second aerobic reactor 14 provided with at least a first 14a and a second inlet 14b respectively set up to receive respectively:
• This second aerobic reactor 14 is thus configured so as to make the second portion (VFAb) of the VFA solution react with the enriched bacterial population 4 to obtain products 5 rich in polyhydroxyalkanoates.
• the products 5 in outlet from the second aerobic digester 14 are preferably composed of an aqueous part and a dry part.
• the dry part has a flow rate of between 15 and 30 kg/h, preferably approximately 23 kg/h.
• the second aerobic reactor 14 preferably, comprises an aerated tank into which the enriched bacterial population 4 is inoculated (through the second inlet 14b).
• the second aerobic reactor 14 is a continuous flow stirred-tank reactor CSTR 28 (structurally alike the one described above).
• first inlet 14a might be in direct connection with the anaerobic digester 12, in particular with a further outlet 12c thereof (figure 2) or through the storage tank 19 (figure 1 ).
• the storage tank 19 is in effect also provided with a second outlet 19b connected to the second aerobic reactor 14 (i.e. to the first inlet 14a thereof).
• the method comprises a final step of separation of the products 5 into a useful fraction 5a', defined mainly by polyhydroxyalkanoates (PHA), and a residual fraction 5b, 5a", defined mainly by a cellular residue.
• a useful fraction 5a' defined mainly by polyhydroxyalkanoates (PHA)
• a residual fraction 5b, 5a defined mainly by a cellular residue.
• the plant comprises separating means 15 operatively positioned downstream of the second aerobic reactor 14 and configured so as to split the products 5 into a usable fraction 5a', mainly made up of polyhydroxyalkanoates (PHA), and a residual fraction 5b, 5a", at least partly made up of a cellular residue 5a".
• separating means 15 operatively positioned downstream of the second aerobic reactor 14 and configured so as to split the products 5 into a usable fraction 5a', mainly made up of polyhydroxyalkanoates (PHA), and a residual fraction 5b, 5a", at least partly made up of a cellular residue 5a".
• PHA polyhydroxyalkanoates
• the step of separating preferably comprises a sub-step of filtering, in which the products are divided into a solid portion 5a and a liquid portion 5b.
• liquid portion 5b is strongly alkaline; in the light of this, in the embodiment of figure 3 the liquid portion 5b is collected and introduced into the second stage 34 of the selector device 32 (that is of the pertraction device 32a).
• the filtration sub-step is preferably performed using mechanical separating means 30, such as for example a centrifuge, a decanter or a filtration apparatus.
• the separating step also comprises a sub-step of extraction, subsequent to the step of filtering, in which the useful fraction 5a' is extracted from the solid portion 5a, leaving a cellular residue 5a", performed by suitable extractor organs 31 .
• the residual fraction is defined by the liquid portion 5b and the cellular residue 5a".
• the liquid portion 5b (or clarified solution) is preferably re-introduced in the process internally of the anaerobic digester 12.
• the cellular residue 5a" is reintroduced into the process during the step of decomposition (that is, internally of the heating means).
• the residual fraction is re-introduced before or during the thermochemical treatment.
• the plant 100 comprises recirculating means 20 associated with the separating means (in particular the extractor organs 31 ) configured so as to:
• these recirculation means 20 can be defined by a conveyor belt, by a screw conveyor or by vehicles controlled by an operator, as well as automated.
• the plant 100 preferably also has a system of actuators and sensors which enables dynamic control of the reactions.
• the plant 100 comprises a plurality of actuator means18, 22, 23, a plurality of sensor means 24 and a control unit 25 associated thereto and configured such as to control the actuator means 18, 22, 23 as a function of respective signals received by the sensor means 24.
• the plant comprises first actuator means 18 (corresponding to the previously-described feed means) operatively interposed between the anaerobic digester 12 and the first aerobic reactor 13.
• the first actuator means 18 are configured for collecting the first portion
• VFA a VFA a
• the plant comprises second actuator means 22 operatively interposed between the anaerobic digester 12 and the second aerobic reactor 14.
• the second actuator means 22 are configured to collect said second portion (VFAb) of the VFA solution and send it to the second aerobic reactor 14.
• the second actuator means 22 are preferably located at the second outlet
• the plant also comprises third actuator means 23 operatively interposed between the tank 21 and the first aerobic reactor 13.
• the third actuator means 23 are configured for collecting the inorganic nutrient products 7 and sending them to the first aerobic reactor 13.
• actuators are present in the plant, such as for example the hydraulic suction pump of the portion 2a of anaerobic bacterial population. However, in the majority of cases these actuators not are piloted by the dynamic control system.
• the sensor means 24 are associated with the anaerobic digester 12, with the first aerobic reactor 13 and with the second aerobic reactor 14 for detecting a plurality of parameters representative respectively of said anaerobic digestion and said aerobic reactions.
• the sensor means 24 comprise at least a first sensor group 24a associated with the anaerobic digester 12 and configured for detecting one or more of the following parameters:
• the means sensors 24 comprise at least a second group sensor 24b associated to the first aerobic reactor 13 and configured for detecting one or more of the following parameters:
• the sensor means 24 comprise at least a third sensor group 24c associated to the second aerobic reactor 14 and configured for detecting one or more of the following parameters: -pH;
• the sensor means 24 comprise at least a first sensor group 24d associated to the anaerobic digester 15 and configured for detecting one or more of the following parameters:
• the fourth group sensor 24d is divided into a first sensor 24d' associated to mechanical separating means 30 and a second sensor 24d" associated to the extractor means 31 .
• the control unit 24 is operatively associated with the first 18, second 22 and third 23 actuator means and with the sensor means 24 and:
• the invention achieves the preset aims and provides major advantages. In effect, with the method and the plant of the present invention it is possible to obtain bioplastic starting from print waste, thus considerably increasing the use of these materials and achieving excellent yield.
• bio-char as nutrient and additive in anaerobic digestion increases the stability of the reactions, thus considerably limiting the waste material from the plant.
• thermochemical treatment of cellular residue following extraction newly enables increasing the of the plant yield, thus minimising waste products.

Landscapes

• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Zoology (AREA)
• Wood Science & Technology (AREA)
• Health & Medical Sciences (AREA)
• Bioinformatics & Cheminformatics (AREA)
• Biotechnology (AREA)
• Genetics & Genomics (AREA)
• General Health & Medical Sciences (AREA)
• Biochemistry (AREA)
• Microbiology (AREA)
• General Engineering & Computer Science (AREA)
• Sustainable Development (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Biomedical Technology (AREA)
• General Chemical & Material Sciences (AREA)
• Molecular Biology (AREA)
• Analytical Chemistry (AREA)
• Clinical Laboratory Science (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Apparatus Associated With Microorganisms And Enzymes (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=51265726

Family Applications (1)

Country Status (2)

Families Citing this family (2)

Family Cites Families (6)

• 2015
  • 2015-06-10 WO PCT/IB2015/054371 patent/WO2015189775A1/en active Application Filing
  • 2015-06-10 EP EP15732434.4A patent/EP3155114A1/de not_active Withdrawn

Also Published As

Similar Documents

Legal Events