Method for treating composite material waste, apparatus for carrying out the method, and regenerated fibers obtained thereby

Abstract

The present invention relates to a method for treating a composite material containing reinforcing fibers and an organic compound, wherein the post-treatment step of oxidizing the composite material comprises: heating a reactor (100) to a first temperature of 300°C to 600°C; injecting oxygen into the reactor configured to produce (provide) an oxygen content consisting of 2% to 15% of the reaction volume of the reactor; the vapor being superheated to a temperature ranging from 300°C to 600°C; and oxidizing the organic compound to CO and / or CO2. The present invention also relates to a treatment apparatus configured to carry out this method, and to the regenerated fibers obtained thereby.

Description

Technical Field

[0001] The present invention relates to a method for treating (processing) composite material waste.

[0002] In particular, the present invention relates to a method for treating and processing fiber-reinforced composite materials, such as, for example, mainly carbon fibers, or glass fibers, or basalt fibers, or other fibers (elements with expired service life generated from manufacturing waste, aviation, automotive, shipbuilding industries, etc.), that is, materials containing fibers at least partially coated with organic compounds.

[0003] The present invention also relates to a processing apparatus configured to carry out this method.

[0004] Finally, the present invention also relates to recycled fibers obtained by this method.

Background Art

[0005] The composite materials considered here typically include fibers and a matrix (base material) coated with the fibers (i.e., an organic compound, such as an organic resin of a polymer material).

[0006] To recycle such materials, one possibility is to separate the matrix (base material) from the fibers, that is, to remove the fibers from the matrix surrounding the fibers, thereby recovering at least the constituent materials (substances) of the fibers (e.g., carbon, glass, basalt, etc.) with as few impurities as possible.

[0007] For this purpose, the composite material can undergo a pyrolysis or steam pyrolysis process.

[0008] For example, in the steam pyrolysis process, pyrolysis in the presence of superheated steam and in the absence of oxygen enables the decomposition of the organic matrix of the composite material. In this process, compared with the conventional pyrolysis process, a medium with a higher oxidizing power enables more complete decomposition of the polymer constituting the matrix, while at the same time, the operating conditions are not so severe (for example, the temperature is low or the residence time is short), which makes it possible to reduce damage to the fibers. Subsequently, the thermolysis reactor operates, for example, in an atmosphere slightly under reduced pressure.

[0009] For example, the fibers obtained after steam pyrolysis (in the case of carbon fibers, also represented as "rCF", which is an abbreviation of "Recovered Carbon Fibres") can be used in the manufacture of subsequent products and are then called "semi-finished products (such as chopped fibres, short fibres, non-woven fibres, spun yarns of discontinuous fibres, yarns, etc.)". This is because these products can then be used as raw materials for manufacturing composite materials based on recycled materials. Therefore, these semi-finished products are intended for the manufacture by third-party manufacturers of new composite materials for, for example, the automotive, shipbuilding, aeronautical construction, or energy industries.

Disclosure of the Invention

Problems to be Solved by the Invention

[0010] However, it may be difficult to remove the resin in a simple pyrolysis or steam pyrolysis step.

[0011] As a result, undesirable organic compounds may remain on the fibers.

[0012] Therefore, an object of the present invention is to provide a method for treating a composite material that improves the removal of organic compounds on reinforcing fibers.

Means for Solving the Problem

[0013] To achieve this object, according to a first aspect of the present invention, there is provided a method for treating a composite material including reinforcing fibers and an organic compound that at least partially coats one of the fibers, the method including a post-oxidation treatment step of the composite material in a reaction apparatus, the post-oxidation treatment step including the following: - a step of heating the reaction apparatus at a first temperature ranging from 300 °C to 600 °C; - a step of injecting oxygen (O2) into a reaction apparatus configured to produce (provide) an oxygen content ranging from 2% to 15% of the reaction volume of the reaction apparatus, - a step of injecting vapor into the reaction apparatus; the vapor is superheated to a temperature, for example, ranging from 300 °C to 600 °C which is the first temperature, and - a step of oxidizing the organic compound to carbon monoxide (CO) and / or carbon dioxide (CO2).

[0014] Thus, the post-oxidation treatment herein refers to an oxidation step of the material performed after a pyrolysis (or steam pyrolysis) type treatment in a reaction apparatus.

[0015] This method then includes an additional treatment step: a post-oxidation treatment step, which can be performed in addition to the pyrolysis or steam pyrolysis step to remove the organic compound. The post-oxidation treatment step herein consists of injecting a controlled amount of oxygen into a reaction apparatus maintained at a specified and controlled temperature.

[0016] In the context of the treatment of the composite material considered here, this post-oxidation treatment step is configured to oxidize the organic compound still present on the fibers to convert it to carbon monoxide (CO) and / or carbon dioxide (CO2).

[0017] Thus, such a process enables the removal, regardless of the operating conditions, not only of a part of the organic compounds that are not decomposed, or cannot be decomposed, or cannot be completely decomposed by pyrolysis or steam pyrolysis, but also, if appropriate, of other organic compounds (such as tar, carbides, or other residues) that can be obtained by the conversion of the organic compounds of the composite material during a prior pyrolysis or steam pyrolysis step.

[0018] In particular, the step of injecting steam into the reactor during the post-oxidation treatment step has the advantage of enabling the stabilization of the post-oxidation reaction, for example, by stabilizing the temperature of the reactor.

[0019] For example, it is also possible to limit (reduce) the risk of fire; without steam, there may be combustion problems.

[0020] As an example, the step of injecting oxygen into the reactor may include the injection of pure oxygen, or any gas containing oxygen such as air, for example, or a nitrogen-dioxygen complex (nitrogen dioxide).

[0021] As an example, the reactor in which the post-oxidation treatment step is carried out is the same as the reactor in which pyrolysis or steam pyrolysis is carried out. However, nevertheless, it can also be configured as another reactor downstream of the reactor intended for pyrolysis or steam pyrolysis.

[0022] As an example, oxygen is injected into the reactor at an ambient temperature (atmospheric temperature) of, for example, 15°C to 50°C.

[0023] As another example, oxygen is injected into the reactor, for example, at 50°C to 600°C, for example, at 300°C to 600°C, after being heated to a first temperature, for example.

[0024] As an example, oxygen is injected into the reactor over a period of 10 minutes to 6 hours.

[0025] For example, oxygen is injected into the reactor at a flow rate adjusted to reach and then maintain an oxygen (O2) content in the reactor of 2% to 15%.

[0026] Therefore, the flow rate can vary very flexibly, for example, between 10 and 1,000 m 3 / h.

[0027] As an implementation example, the post-oxidation treatment process includes the following: - A step of lowering the temperature in the reactor from a first temperature to a second temperature. The second temperature consists of 300°C to 500°C (due to the organic compound); - A step of maintaining the second temperature in the reactor for a period ranging from 10 minutes to 6 hours; and - A step of introducing oxygen (O2) into the reactor.

[0028] As an example, the post-oxidation treatment process may further include a step of reducing the steam injection into the reactor.

[0029] When the steam injection decreases, the steam injection flow rate decreases, which depends, for example, on the size of the reactor (e.g., the internal volume of the reactor and / or the amount of the substance to be treated present in the reactor).

[0030] As an implementation example, the steam injection can be stopped (i.e., the flow rate is 0 m 3 / hour).

[0031] In practice, since the post-oxidation treatment reaction can be exothermic, the temperature in the reactor can vary frequently.

[0032] Nevertheless, the post-oxidation treatment may be carried out at least partially after or during the temperature reduction step.

[0033] As an example, the post-oxidation treatment step may further include at least one step of simultaneously or alternately analyzing (measuring) the flow rates of steam and dioxygen (O2) in order to maintain the temperature of the reaction medium and the dioxygen (O2) content at 300°C to 600°C and 2% to 15%, respectively.

[0034] As an example, the step of lowering the temperature from the first temperature to the second temperature includes the step of lowering the temperature of the superheated steam injected into the reactor.

[0035] As an example, this method includes the step of measuring the amount of oxygen at the exhaust port of the reactor.

[0036] As an example, the step of introducing oxygen into the reactor includes the step of adjusting the injection flow rate according to the oxygen content at the exhaust port of the reactor.

[0037] For example, when the oxygen content is stable, the method of the present invention includes the following: - The step of stopping oxygen injection; and / or - The step of stopping the heating of steam; and / or - The step of cooling the reactor including the saturated steam injection step.

[0038] "Stable" means that, for example, for at least 10 minutes, ranging from 10 minutes to 30 minutes, the fluctuation of the oxygen content is less than 20% or less than 10%.

[0039] If the oxygen content is stable, then the oxidation is completed thereafter. As a result, the injection of oxygen can be stopped and / or the reactor can be cooled.

[0040] The saturated steam here refers to the steam at the liquid-vapour equilibrium point (and thus is composed of non-superheated steam).

[0041] In this framework, it is injected at a temperature of 100°C to 170°C.

[0042] Next, this method includes, for example, a step of emptying the reaction apparatus.

[0043] Thereafter, this method can be repeatedly executed for the new contents in the reaction apparatus.

[0044] As an example, this method includes, before the oxidation post-treatment step, a step of pyrolyzing or steam-pyrolyzing a composite material including fibers and an organic matrix in the reaction apparatus.

[0045] For example, the pyrolysis step or the steam-pyrolysis step is configured to produce recycled fibres and decompose the organic matrix into at least one organic compound.

[0046] The reaction apparatus may be the same as the one in which the oxidation post-treatment step is carried out, or another reaction apparatus upstream of the one used for the oxidation post-treatment step.

[0047] According to a second aspect (feature) of the present invention, there is provided a processing apparatus configured to execute the method for processing the aforementioned composite material.

[0048] As an example, the apparatus includes at least one reaction apparatus.

[0049] For example, the reaction apparatus is configured to execute both the steam-pyrolysis step and the oxidation post-treatment step.

[0050] For example, the reaction apparatus includes a supply inlet configured to supply the composite material to be processed into the reaction apparatus, and further an outlet from which so-called "recycled" fibres are recovered.

[0051] As an example, the apparatus includes a steam superheater.

[0052] For example, the steam superheater is configured to inject superheated steam into the reactor.

[0053] For example, the steam superheater is located upstream of the reactor.

[0054] For example, the steam superheater is set to raise the temperature of the steam from 300°C to 600°C and is configured to inject it into the reactor.

[0055] As an example, the apparatus includes at least one sensor configured to control the post-oxidation treatment process.

[0056] For example, the at least one sensor includes, for example, at least one temperature sensor and / or an oxygen content sensor. It is also possible to include a pressure sensor.

[0057] As an example, the apparatus includes a control unit configured to automatically control the post-oxidation treatment process based on data transmitted by at least one sensor.

[0058] For example, it consists of an automation system for controlling the post-oxidation treatment process and all related operating mode parameters.

[0059] As an example, the apparatus includes a water treatment unit configured to treat running water (tap water) to provide infiltrated water.

[0060] As an example, the apparatus includes a storage unit configured to store the infiltrated water and also configured to supply the infiltrated water to, for example, a thermal oxidizer and / or a steam generator.

[0061] As an example, the apparatus includes a steam generator configured to superheat the infiltrated water and supply saturated steam to the steam superheater.

[0062] As an example, the apparatus includes a thermal oxidiser configured to process vapours and gaseous products (gaseous products) generated from a reactor.

[0063] As an example, the apparatus includes a primary exchanger configured to circulate permeated water within the thermal oxidiser.

[0064] For example, the primary exchanger is a plate exchanger.

[0065] As an example, the apparatus includes a secondary exchanger configured to circulate an air coolant such as glycolated water.

[0066] For example, the secondary exchanger is connected to the primary exchanger.

[0067] According to a third aspect (feature) of the present invention, recycled fibres obtained by the method of treating the aforementioned composite material are also provided.

[0068] In particular, the recycled fibres contain fibres such as carbon fibres, glass fibres, basalt fibres, etc. and residues of organic compounds in an amount of 0 wt% to 5 wt%, or 0 wt% to 1 wt%.

[0069] Here, the percentage denoted as "wt%" indicates the weight percentage.

[0070] In certain embodiments, the recycled fibres do not contain residues of organic compounds (which corresponds to a content of 0 wt%).

[0071] According to one embodiment, the present invention will be fully understood and its advantages will become more apparent by reading the following detailed description with reference to the accompanying drawings shown below, which are for illustrative purposes only and are in no way limiting:

Brief Description of the Drawings

[0072]

Figure 1

[0073] Ranges of values are shown as examples of pilot installations; they need to be adjusted (adapted) according to the capacity of the reactor mainly used.

Modes for Carrying Out the Invention

[0074] The following description relates to a method of treating a composite material comprising carbon fibers (although it may be composed of other types of fibers such as, for example, glass fibers, basalt fibers, etc.) and an organic compound that at least partially coats one of the fibers, and includes a post-treatment step of oxidizing the material, which is carried out after the step of vapor pyrolysis of the composite material comprising the fibers and the organic matrix. Nevertheless, this can be a simple thermolysis step. It also relates to an apparatus configured to carry out this method. For example, the pyrolysis or steam-thermolysis step is configured to produce (provide) the fibers and decompose the organic matrix into at least one organic compound.

[0075] Vapor pyrolysis enables the decomposition of the organic matrix of a composite material by pyrolysis in the presence of superheated steam and in the absence of oxygen. This process allows for a more complete decomposition of the polymer compared to conventional pyrolysis processes by using a medium with a higher oxidizing power, while at the same time reducing fiber damage due to less severe operating conditions (e.g., lower temperature or shorter residence time). Generally, a thermolysis reactor operates in an environment that is very slightly under vacuum (under atmospheric pressure).

[0076] In the examples of this specification, the possible composite materials used at the inlet of the method mainly include thermosetting (e.g., epoxy, polyester, vinyl ester, or other types) or thermoplastic (e.g., polyamide, polypropylene, polyether ether ketone, polyphenylene sulfide, or other types) organic compounds composed of polymer resins, prepregs, or sized and dried fibers. The fiber content of the tested laminated composite or prepreg composite ranges from 20% to 70%, up to 80% at most. In the case of dry fibers, this fiber content can increase up to 99% at most.

[0077] As shown in Figure 1, the apparatus configured to perform the method described below mainly comprises a reactor 100.

[0078] In this embodiment, the reactor 100 is configured to perform both a vapor pyrolysis (or pyrolysis) step and an oxidation post-treatment step.

[0079] Nevertheless, in another embodiment, the apparatus described here may include two separate reactors, one for performing the pyrolysis or vapor pyrolysis step and the other for performing the oxidation post-treatment step.

[0080] For example, the following table shows the characteristics of a reactor suitable for the framework of the present invention:

[0081]

Table 1

[0082] As a result, in this reactor 100, a supply port (supply inlet) 1 configured to supply a base composite material to be processed, that is, a composite material including fibers and an organic matrix herein, into the reactor, and an outlet 2 from which so-called "recycled" fibers are recovered are provided. The fibers here include, for example, fibers and residues of organic compounds of less than 5% by mass, or less than 1% by mass.

[0083] In this case, the reactor operates mainly electrically, for example.

[0084] For example, the reactor 100 includes an air injection inlet 101 and a superheated steam inlet 102.

[0085] In particular, the air injection inlet 101 is useful for a treatment cycle including a post-oxidation treatment step according to, for example, an embodiment of the present invention.

[0086] For example, the reactor 100 is a vacuum-controlled sealed electric furnace with forced convection opened by a single hinged door on one side. It is mainly composed of a reaction region with an effective volume of 3.375 m 3 . The heating of the reactor is ensured by six sets of electrical resistances with a total power of 118 kW.

[0087] In order to inject (supply) superheated steam, this device is equipped with a steam superheating device 103.

[0088] For example, the following table shows the characteristics of a superheating device suitable for the framework of the present invention:

[0089]

Table 2

[0090] In this embodiment, the superheater operates mainly electrically, for example.

[0091] Next, the superheater 103 includes a superheated steam outlet 104 connected to a superheated steam inlet 102 of the reactor 100 via a duct, for example, and a saturated steam inlet 118 that enables the supply of steam.

[0092] For these purposes, the apparatus includes a water treatment unit 105.

[0093] In this embodiment, the water treatment unit operates mainly electrically, for example.

[0094] Therefore, the water treatment unit includes a running water supply inlet 106.

[0095] In this embodiment, the water treatment operation is performed in a loop independent of the rest of the process. For example, the start of this unit operation is servo-controlled by the filling level of the storage unit 109. For example, an adjustable minimum water level can be the trigger for operating the water treatment section. For example, the production cycle can be started only when the water level is higher than the limit equal to the amount of water required for steam generation over the entire batch period. Therefore, this method is independent of possible accidental water shortages.

[0096] For example, the water treatment operation is performed in the following two steps: - Softening of water by two exchange resin trays. Calcium ions and potassium ions contained in the water of the network are exchanged with sodium ions in order to greatly limit the possibility of limestone formation during evaporation. - Reverse osmosis to reduce the concentration of ionic species that may produce precipitates.

[0097] Thus, the running water is treated in the water treatment unit 105 which provides osmosed water on the one hand and eluate on the other hand. Therefore, the water treatment unit 105 is provided with an osmosed water outlet 107 and an eluate outlet 108.

[0098] To store the osmosed water, the device is provided with a storage unit 109.

[0099] Such a storage unit has a capacity of several cubic meters, for example 5 m 3 to 10 m 3 and has a capacity of.

[0100] At the outlet of the storage unit 109, two pumps enable the supply of steam products and the supply of the cooling system of the thermal oxidizer 120.

[0101] Therefore, the storage unit 109 is provided with an osmosed water inlet 110 connected to the osmosed water outlet 107 of the water treatment unit 105. Furthermore, the storage unit 109 is provided with a first osmosed water outlet 111 configured to supply the cooling system of the thermal oxidizer 120 and a second osmosed water outlet 112 configured to supply the steam generator 113.

[0102] To generate saturated steam, the device is provided with a steam generator 113.

[0103] For example, the following table shows the characteristics of a steam generator suitable for the framework of the present invention:

[0104]

Table 3

[0105] Here, the steam generator operates, for example, on electricity or natural gas.

[0106] In order for the osmosed water to be supplied, the steam generator 113 is provided with an osmosed water inlet 114, and therefore, this osmosed water inlet 114 is connected to a second osmosed water outlet 112.

[0107] The steam generator 113 also includes a combustion air inlet 115.

[0108] At the outlet, the steam generator includes a liquid effluent outlet 116.

[0109] It also includes a saturated steam outlet 117 configured to supply the steam superheater 103.

[0110] The saturated steam outlet 117 is connected to the saturated steam inlet 118 of the steam superheater 103, for example, via a duct.

[0111] For example, the device uses a steam generator and a superheater that include, for example, a pharmaceutical-type water-quality steam generator. This water quality is defined by the specifications of the device in order to avoid possible dirt and damage that may occur in this device.

[0112] Thanks to the use of very pure water, this device can generate steam very rapidly.

[0113] For example, the water in the steam generator has the following characteristics:

[0114]

Table 4

[0115] Furthermore, the reactor 100 is provided with an outlet for steam and gaseous products 119.

[0116] Downstream, the device is provided with a thermal oxidizer 120.

[0117] In this case, the thermal oxidizer 120 operates with, for example, electricity or natural gas.

[0118] The thermal oxidizer 120 is provided with an inlet for steam and gaseous products 121, which is connected, for example via a duct, to the outlet for steam and gaseous products 119 of the reactor.

[0119] The thermal oxidizer 120 is also provided with a first osmosed water inlet 122, which is connected, for example by way of example via a duct, to the first osmosed water outlet 111 of the storage unit 109.

[0120] Here, the thermal oxidizer 120 is provided with a second osmosed water inlet 123 configured to receive osmosed water from the primary exchanger 127.

[0121] The thermal oxidizer 120 also comprises, for example, air supply inlets 124 which are inlets for quench air and combustion air.

[0122] At the outlet, the thermal oxidizer 120 comprises an outlet 125 for the treated gaseous effluents.

[0123] Finally, the thermal oxidizer 120 comprises an osmosed water outlet 126 configured to return the osmosed water to the primary exchanger 127.

[0124] For example, the thermal oxidizer 120 according to an embodiment of the present invention is sized to have two combustion zones, namely a first combustion zone at 900 - 1,100 °C and a second combustion zone at 850 - 950 °C.

[0125] For example, the following table shows the characteristics of an oxidiser suitable for the framework of the present invention:

[0126]

Table 5

[0127] The device further comprises a primary exchanger 127 configured to circulate the osmosed water within the thermal oxidizer 120.

[0128] In this case, the primary exchanger operates mainly electrically, for example.

[0129] To achieve the purpose, in the primary exchanger, for example, there is an osmosed water inlet 128 connected to the permeate water discharge port 126 of the thermal oxidation device 120 via a duct, and an osmosed water outlet 129 connected to the second osmosed water inlet 123 of the thermal oxidation device 120 via a duct, for example. The primary exchanger 127 also includes a glycolated water inlet 133 and a glycolated water outlet 134 here.

[0130] Finally, the device includes a secondary exchanger 130 configured to circulate glycolated water.

[0131] In this case, the secondary exchanger operates mainly electrically, for example. Here, the secondary exchanger 130 includes a glycolated water inlet 131 connected to the glycolated water outlet 134 of the primary exchanger 127 via a duct, for example, and a glycolated water outlet 132 connected to the glycolated water inlet 133 of the primary exchanger 127 via a duct, for example.

[0132] During operation, upstream of all operations of the reactor 100, this method includes the step of operating the thermal oxidation device 120 and maintaining it in a steady state.

[0133] Thereby, the operation of raising and lowering the temperature of the reactor 100 results in a low discharge level, and the risk of a discharge level higher than the steady state of the reactor occurring is highly restricted and can be avoided.

[0134] Thus, since the thermal oxidizer 120 operates in a steady state, this method will include the steps of loading the base composite material to be processed into the reactor 100, and first heating the reactor under air and then heating it to the processing plateau temperature under superheated steam.

[0135] The temperature plateau is maintained for a time necessary to maximally remove the organic matrix on the fibers of the base composite material.

[0136] Thereby, during the stage of reducing the temperature of the reactor by injecting saturated steam, minimal organic compounds are released from the reactor towards the thermal oxidizer 120 or not released at all.

[0137] To avoid condensation of the steam in the oxidizer as much as possible, the operation of the oxidizer is maintained during this stage (step).

[0138] The preparation and loading operations of the base composite material are carried out in batches. For example, parts made of recycled composite materials are pre-classified by type of fiber and organic compound in order to process one type of material in a batch. Next, the parts are loaded onto a support that can be transported by a lift truck or forklift.

[0139] This support is configured to ensure an optimal distribution of the temperature and steam throughout the reactor. Also, at the end of the steam-thermolysis step, the collection (recovery) of the recycled fibers is ensured to secure a firm mechanical cohesion.

[0140] For example, the support is a metal cube equipped with a system for cooperating with a forklift (or trolley), and it has a shelf-like system (i.e., a rack system) for arranging the material and properly dispersing the temperature.

[0141] In order to accurately control the method and control the quality of the decomposition of the organic compound, the composite material to be processed is weighed using weights (weights: scales), for example, before being inserted into the reactor and at the outlet (end) of the process.

[0142] Subsequently, the support is introduced into the reactor together with the composite material to be processed (previously washed if necessary).

[0143] For example, each batch is composed of at most 2,000 kg of composite material.

[0144] 1. Generation of steam The steam essential for the steam pyrolysis reaction is generated here by a steam generator 113 and a (steam) superheater 103. In the process (method) described here, the steam has the following two functions: - A function of inactivating the reaction medium to limit the oxygen concentration and avoid the occurrence (generation) of oxidation reactions in the reactor. - A catalytic function by lowering the thermal decomposition temperature of the organic compound.

[0145] First of all, the infiltrated water is sent into the storage unit 109, where the oxygen content and pH value decrease.

[0146] The steam discharged from the steam generator is adjusted by a separator so that the steam titre exceeds 99%.

[0147] Subsequently, the dry steam thus generated is expanded to about 100 kPa and then superheated by the (steam) superheater 103 so as to reach the conditions desirable for use in this method.

[0148] The pressure rise of the steam device is very rapid (in the case of the steam generator 113, 3 to 4 minutes), and it is carried out when the temperature of the reactor exceeds, for example, 160 °C in order to avoid any condensation phenomenon in the chain of gaseous effluent treatment.

[0149] The steam generator 113 operates at the same speed throughout the entire processing batch. Therefore, the mass flow rate of the steam becomes a fixed parameter in this method. The temperature of the steam is adjusted using the superheater 103 during the heating-up and cooling-down phases of the equipment.

[0150] Saturated steam is generated in the steam generator, which is an instantaneous vaporisation steam generator with an output of 800 - 1,000 kW operating on, for example, natural gas, and is configured to generate the first part (the first stage) of superheating. Such technology also enables very rapid pressurisation and is compatible with a batch process. The steam quality at the steam generator outlet is higher than 99% (i.e., in the range of 99% - 100%), which corresponds to pharmaceutical or food standards.

[0151] When the steam is discharged from the steam generator, it is sent to the superheater 103 that handles the completion of superheating, and as a result, it reaches, for example, 500 °C at 101,325 Pa (Pascal).

[0152] 2. Steam pyrolysis reaction In the reactor 100, the action of the temperature in an atmosphere (atmospheric environment) inactivated by superheated steam enables the thermal decomposition of the organic matrix in the form of gaseous products.

[0153] Throughout the process, continuous oxygen measurement within the reactor 100 and emergency nitrogen injection when the oxygen concentration reaches at least 8% are carried out (provided). An important point of this equipment regarding product quality is the uniformity of the temperature and the steam flow. The composite materials are loaded onto a loading support, which is configured not to create dry or low-temperature regions within the reactor.

[0154] The controllable stirring fan achieves homogenization at approximately 1.5 °C at the Plateau temperature. Superheated steam is injected into the reactor in a subordinate manner to ensure inactivation and generate the atmosphere (atmospheric environment) required for steam pyrolysis. This steam and the pyrolysis gas products are continuously extracted from the reactor by a hot gas extractor equipped with a remote belt drive and controlled by the reduced pressure value of the reactor.

[0155] Steam is injected when the temperature of the reactor is higher than the condensation temperature (160 °C) at 700 kPa. Subsequently, the temperature rise continues according to a given Plateau temperature composed in the range of 300 - 600 °C. For example, the total continuous time of these temperature plateaus consists of 2 to 4 hours. For example, the ratio of the flow rate of the injected steam to the mass of the composite material is 0.5 - 1.5.

[0156] When the temperature reaches the plateau, the heating of the reactor is stopped, and the reactor is cooled by injecting saturated steam, and then injecting outside air and nitrogen (if necessary). When the temperature reaches 140 °C, the door of the reactor can be opened. Subsequently, the cooling continues until it drops to 50 - 60 °C, at which temperature the loading support can be removed from the reactor.

[0157] 3. Oxidation post-treatment In addition to the pyrolysis or steam pyrolysis treatment, the treatment method according to the present invention enables the execution of post-treatment. This supplementary treatment is the so-called "oxidation post-treatment".

[0158] In fact, a part of the waste consists of a part of the organic compounds that cannot be completely removed only by the completion of pyrolysis or steam pyrolysis. Therefore, a second treatment step, the oxidation post-treatment step, is required. The oxidation post-treatment step essentially consists of injecting a controlled amount of oxygen into the reactor maintained at a defined and controlled temperature to oxidize the organic compounds still remaining on the fibers and convert them into CO and CO2.

[0159] Regardless of the operating conditions, it is possible to remove, by pyrolysis or steam pyrolysis, a part of the organic compounds that are not decomposed, or non-decomposable, or not completely decomposable, and, if necessary, other organic compounds (such as tar, carbide, or other residues) that can be obtained by the change (alteration) of the organic compounds of the composite material during the previous pyrolysis or steam pyrolysis process. For this purpose, oxygen injection is carried out, for example, by injecting air into the reaction medium using a dedicated valve.

[0160] This injection can be carried out as follows: - After the complete pyrolysis or steam pyrolysis reaction (all that can be decomposed by pyrolysis or steam pyrolysis have already been decomposed); - With or without maintaining steam injection in parallel (for example, air injection containing O2); - Preferably, between 300 and 600 °C - Usually, for a time ranging from 20 minutes to 6 hours.

[0161] The choice of various other methods depends on the material to be processed and the desired (required) content of residual organic compounds. For example, preliminary analysis in the laboratory allows estimating the amount of material to be decomposed and enables appropriate treatment (such as the duration and flow rate of O2).

[0162] For example, the end of the oxidation reaction is measured by the O2 level at the exhaust of the reactor stabilizing, for example, at about 20 - 21%.

[0163] For example, three embodiments according to the present invention are described below, in which a temperature plateau is achieved at a temperature ranging from 400 °C to 600 °C, as a result of which the pyrolysis / steam pyrolysis reaction is completed;

[0164] As a first embodiment, the method includes a step of lowering the temperature inside the reactor device, and then a step of finally stopping the injection of steam and maintaining this temperature until only air is introduced into the reaction medium, for example, at a controlled flow rate. To do this, for example, in the first step, the superheater is stopped and cooling is advanced to inject saturated steam (for example, 100 °C) into the reactor. When the temperature of the reaction medium is reached, the injection of steam is stopped, and the temperature is maintained, for example, by the action of the heating resistor of the reactor device, and outside air is introduced into the reactor device. For example, the adjustment of the air injection flow rate is performed based on the O2 content at the exhaust port of the reactor device. When this ratio approaches 20 - 21%, the post-oxidation treatment step is completed, and for example, saturated steam is injected again to advance the cooling of the product.

[0165] As a second embodiment, since some compounds need to perform the post-oxidation treatment step at 500 °C, the reaction medium is not cooled. Nevertheless, unlike the first embodiment, the injection of superheated steam at about 500 °C is maintained to more quickly update the reaction volume and as a result maintain a stable temperature. For example, outside air is injected into the reaction medium at 500 °C not by adjusting the O2 content at the outlet anymore (for example, oxygen is diluted in the steam), but by injecting a constant air flow over a defined plateau period. In fact, the mass of O2 injected is defined by the mass of the organic compound being treated by the post-oxidation treatment, and as a result, it is possible to determine which air flow to introduce and for which period. Similar to the first embodiment, when the reaction is completed, the injection of air can be stopped to heat the steam to promote the cooling of the product by the saturated steam.

[0166] As a third embodiment, the first and second embodiments are integrated. That is, the method first includes a cooling step, and then, for example, a step of slowly heating the reaction medium during the post-oxidation treatment step to control not only the air flow rate but also the post-oxidation reaction temperature. However, this embodiment takes time and requires more energy.

[0167] Generally, these examples are carried out immediately after the pyrolysis or steam pyrolysis reaction (before the temperature drops and the reaction apparatus is opened). However, they can also be carried out in an independent cycle (after complete cooling and a new temperature increase). However, this incurs additional energy costs (it is necessary to raise the temperature at the start of the second cycle).

[0168] 4. Treatment of Gaseous Products (Gas Products) The gaseous products (gas products) obtained from steam pyrolysis are treated by complete decomposition by thermal oxidation. This apparatus is composed of a low NOx burner, two combustion chambers (combustion rooms), and SNCR (selective non-catalytic reduction) treatment of NOx by urea spraying.

[0169] The pyrolysis gas resulting from the pyrolysis reaction is mainly composed of organic species (C, H, O, N), and carbon dioxide (CO2), water (H2O), and nitrogen oxides (NOx) are produced by thermal oxidation (reaction with oxygen at high temperature). To comply with the emission limits of nitrogen oxides, an example related to a combination of waste control technologies including the following elements is introduced:

[0170] · A low NOx burner that generates little NOx during the oxidation of organic species. · A double oxidation chamber configured to completely oxidize organic compounds without oxidizing nitrogen. · Reduction of residual NOx by "non-catalytic reduction" of spraying urea into the gas stream at a set high temperature. The flow rate of urea is set to be much higher than the amount of NOx to be treated, thereby enabling maximum reduction.

[0171] The first oxidation chamber is controlled in sub-stoichiometry at a very high temperature, and in order to greatly limit the appearance (generation) of nitrogen oxides, this device is provided with a double envelope. This form enables the cooling of the metal structure of the first oxidation chamber. In order to maintain the temperature of the structure within the allowable limits of the material, a rail for spraying infiltrated water at 20 - 50 m 3 / h is installed. The cooling water is collected at the bottom of the double envelope, then sent to a primary exchanger 127 which is a plate exchanger, cooled, and re-injected into the oxidation device 120 as a new cooling cycle.

[0172] For example, 30 m 3 / h to 60 m 3 / h of a countercurrent flow of glycolated water also passes through the plate exchanger (primary exchanger) 127, and finally, thanks to an external closed-circuit air cooler, the extra calories are discharged.

[0173] The gas discharged into the atmosphere is cooled by injecting fresh air (for example, 5,000 - 25,000 Nm 3 / h) at the outlet of the thermal oxidizer 120 in order to limit the temperature in the chimney. For example, in the case of a steel chimney with a diameter of 900 mm - 1,500 mm, the temperature will be 300 - 400 °C, but it is possible to limit (restrict) the discharge rate and / or noise pollution, for example.

[0174] The treatment of the gaseous emissions consists of direct flame oxidation of all the organic species present. In the guidelines for this type of treatment, it is recommended to pass the organic compounds at a high temperature of 850 °C for at least 2 seconds.

[0175] For example, the thermal oxidizer 120 according to an embodiment of the present invention is sized to have two combustion zones, namely a first combustion zone at 900 - 1,100 °C and a second combustion zone at 850 - 950 °C, as described above.

[0176] 5. Handling, quality control, adjustment After cooling the reaction device to 50 to 60 °C or lower, open the reaction device and carry it out using, for example, a forklift. Then, in order to control the decomposition rate of the organic compound in the composite material, weigh the loading (stacking) support with the fibers on the same scale as during loading. Then, the fibers are removed from the loading (stacking) support and placed in the transfer area.

[0177] Samples of the obtained recycled fibers are prepared for quality control of the pyrolysis reaction (to ensure that there are no residual organic compounds on the recycled fibers). If the preliminary control is good, then mechanical quality control of the rCF is carried out. Then, the recycled fibers undergo the following operations: - Sorting: At the exhaust of the steam pyrolysis reactor, the carbon fibers are separated from other wastes (such as bolts); - Conditioning and storage: The sorted rCF is conditioned and stored in cardboard boxes, bags, IBCs, or large bags. - Delivery: Depending on the order, the carbon fibers are packed in cardboard boxes, bags, IBCs, or large bags according to the customer's needs.

Claims

1. In a method of treating a composite material comprising a reinforcing fiber and an organic compound that at least partially coats one of the fibers, the method includes a post-treatment step of oxidizing the material in a reactor (100), the post-treatment step of oxidation including: - heating the reactor (100) to a first temperature in the range from 300°C to 600°C; - injecting oxygen into the reactor (100) configured to produce (provide) an oxygen content of 2% to 15% of the reaction volume of the reactor; - injecting steam into the reactor (100); this steam is superheated to a temperature, for example, in the range from 300°C to 600°C which is the first temperature, and - A step of oxidizing an organic compound to carbon monoxide (CO) and / or carbon dioxide (CO ２ )

2. The method according to claim 1, characterized in that oxygen is injected into the reactor (100) at an ambient temperature (atmospheric temperature), for example, in the range from 15°C to 50°C.

3. The method according to claim 1, characterized in that oxygen is injected into the reactor (100) after being heated, for example, to a temperature in the range from 50°C to 600°C, for example, in the range from 300°C to 600°C, for example, to the first temperature.

4. The method according to any one of claims 1 to 4, characterized in that oxygen is injected into the reactor (100) over a period of from 10 minutes to 6 hours.

5. The post-treatment step of oxidation includes: - reducing the temperature in the reactor (100) from the first temperature to a second temperature. The second temperature is in the range from 300°C to 500°C; - maintaining the second temperature for a period of from 10 minutes to 6 hours; and - introducing oxygen into the reactor (100) The method according to any one of claims 1 to 4, characterized in that.

6. The method according to claim 5, characterized in that the post-treatment step of oxidation includes a step of reducing the injection of steam into the reactor (100).

7. The method according to claim 5 or claim 6, characterized in that the step of introducing oxygen includes a step of adjusting the injection flow rate according to the oxygen content at the exhaust port of the reactor (100).

8. The method according to any one of claims 5 to 7, characterized in that the step of reducing the temperature from the first temperature to the second temperature includes a step of reducing the temperature of the superheated steam injected into the reactor (100).

9. The method according to any one of claims 1 to 8, characterized in that the post-oxidation treatment step includes a step of simultaneously or alternately analyzing (measuring) the flow rates of steam and oxygen in order to maintain the temperature and oxygen content of the reaction medium at 300°C to 600°C and 2% to 15%, respectively.

10. The method includes a step of measuring the amount of oxygen at the exhaust port of the reactor (100), and when the oxygen content is stable, the following steps: - A step of stopping oxygen injection; and / or - A step of stopping heating of the steam; and / or - A step of cooling the reactor (100) including a saturated steam injection step. The method according to any one of claims 1 to 9, characterized by the above.

11. The method according to any one of claims 1 to 10, characterized in that before the post-oxidation treatment step, a step of pyrolyzing or steam pyrolyzing a composite material including fibers and an organic matrix is included in the reactor.

12. In a processing apparatus configured to execute the method for processing a composite material according to any one of claims 1 to 11, the apparatus includes a reactor (100) and a steam superheater (103) upstream of the reactor (100), and the steam superheater (103) is set to raise the temperature of the steam to a temperature from 300°C to 600°C and is configured to inject it into the reactor (100). A processing apparatus characterized by the above.

13. The processing apparatus according to claim 12, characterized in that it includes at least one sensor configured to control the post-oxidation treatment step and a control unit configured to automatically control the post-oxidation treatment step according to (based on) the data transmitted by the at least one sensor.

14. The processing apparatus according to claim 12 or claim 13, characterized in that it includes a water treatment unit (105) configured to treat running water (tap water) to provide infiltrated water.

15. The processing apparatus according to any one of claims 12 to 14, characterized in that it includes a storage unit (109) configured to store infiltrated water.

16. The processing apparatus according to claim 14 or claim 15, characterized in that it includes a steam generator (113) configured to superheat infiltrated water and supply saturated steam to the steam superheater (103).

17. The processing apparatus according to any one of claims 12 to 16, characterized by comprising a thermal oxidizer (120) configured to process vapor and gaseous products (gaseous products) generated from a reaction apparatus (100).

18. The processing apparatus according to any one of claims 12 to 17, characterized by comprising a primary exchanger (127) configured to circulate permeated water within the thermal oxidizer (120).

19. The processing apparatus according to any one of claims 12 to 18, characterized by comprising a secondary exchanger (130) configured to circulate an air-cooled substance such as glycolated water.

20. In the regenerated fiber obtained by the method for processing the composite material according to any one of claims 1 to 11, the regenerated fiber is characterized by comprising a fiber and a residue of an organic compound in an amount of 0% by mass to 5% by mass.

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