Method for desorbing pah from carbon products, corresponding desorber and use of the desorber

Abstract

The present invention relates to an apparatus and a method for the desorption of residues from a carbon product, said method comprising the steps of: introducing a carbon product containing residues (2) into a desorber (1); heating the carbon product (2) within the desorber (1) to a temperature > 700°C, preferably between 700°C - 1500°C, so that the residues in the carbon product (2) are desorbed; introducing a gas stream (3) into the desorber (1) in order to remove the desorbed residues from the carbon product (2) by means of the gas stream (3) and to discharge them from the desorber via a gas outlet (4); transporting the carbon product within the desorber (1) and discharging the carbon product freed of residues (2') from the desorber (1).

Description

[0001] New PCT patent application based on DE 102024 122 258.1 SynCraft Engineering GmbH Vossius Ref.: AE3225 PCT S5

[0002] Methods for the desorption of PAHs from carbon products, corresponding desorbers and use of the desorber

[0003] Field of invention

[0004] 5 The present invention relates generally to a process for the desorption of polycyclic aromatic hydrocarbons (PAHs) or other residues from carbon products to obtain a purified carbon product. In particular, the present invention relates to a thermal process in which unwanted residues are thermally dissolved from a carbon product and removed by means of a gas stream to obtain a purified carbon product that can be used in a variety of applications. Furthermore, the present invention relates to a corresponding device for the desorption of these residues or PAHs, as well as the use of this device and a correspondingly purified carbon product.

[0005] Background of the invention

[0006] 15. Gasification, or thermochemical conversion, has the task of producing, on the one hand, a gas (wood gas; syngas; product gas; low-grade gas) and, on the other hand, a carbon product, such as a type of residual coke, charcoal, or biochar, from carbon-containing materials (e.g., biomass, forest wood chips). A complete thermochemical conversion into a pure carbon product would only be possible under extremely complex conditions.

[0007] High process temperatures and residence times of up to 20 are technically possible. The same applies to pyrolysis processes that precede the gasification process.

[0008] The inventors of the present invention disclosed in granted patent DE 10 2007 012452 B4 a fluidized bed gasifier and a corresponding gasification process that already produces a high-quality carbon product as a byproduct. It is also known that many gasification systems on the market produce carbon products as byproducts without separate afterburning. However, these carbon products are often contaminated by organic residues, such as PAHs (polycyclic aromatic hydrocarbons) or BTXE (benzene, toluene, ethylbenzene, xylenes). The 16 so-called [missing information - likely referring to specific contaminants or substances] are often analytically recorded and totaled.

[0009] 30 'EPA-PAHs' (PAH16), which cover the spectrum from naphthalene with only two rings to the higher molecular weight PAHs with 5 and 6 rings. However, such carbon products contaminated with residues or residual substances cannot be used in many areas.

[0010] For example, the limit values ​​for PAH 16 in agriculture are < 6 mg / kg dry matter (DM), and for organic farming, < 4 mg / kg DM. Therefore, coal or carbon products from most thermochemical processes often cannot be used in these areas.

[0011] It is therefore an object of the present invention to easily remove residual materials or residues such as PAHs from carbon products, thereby making the use of the purified carbon products more diverse.

[0012] Summary

[0013] This problem is solved by the subject matter of the independent claims. Preferred features of the subject matter according to the invention are described in the dependent claims.

[0014] The present invention relates to a method for the desorption of residues from a carbon product, wherein the method comprises at least one of the following steps: introducing a carbon product containing residues into a desorber; heating the carbon product within the desorber to a temperature of at least 700°C, such that at least a proportion of the residues of the carbon product is desorbed; introducing a gas stream into the desorber, such that the desorbed residues are removed from the carbon product by means of the gas stream and discharged from the desorber via a gas outlet; wherein the carbon product remains within the desorber for a residence time; and discharge of the residue-free carbon product from the desorber.

[0015] The residence time can be controlled either within a batch process, i.e., via the time at which the carbon product to be purified is introduced into the desorber and the time at which the purified carbon product is discharged from the desorber. However, the residence time can also be set, controlled, or regulated in a continuous process by adjusting the residence time via the transport rate of the inputs until the discharge of the carbon product. In particular, in a continuous process, it is preferred if the carbon product is transported in the desorber, preferably at a substantially constant rate. Furthermore, it should be noted that a purified end product is "only" purified to a desired degree of purity.In other words, a purified end product should not be considered as an end product from which unwanted residues have been completely removed, but only to a desired degree of purity.

[0016] Preferably, the carbon product is heated inside the desorber to a temperature between 700°C and 1500°C, preferably to a temperature between 700°C and 950°C.

[0017] The residence time of the carbon product in the desorber is preferably shorter than 20 min, preferably shorter than 10 min, preferably shorter than 5 min, preferably shorter than 2 min.

[0018] The carbon product can be any C-containing substance, preferably coal of organic origin, from biomass, from wood, from plants, and / or charcoal.

[0019] Preferably, the carbon product is fed to the desorber from a thermochemical conversion system, wherein the thermochemical conversion system is one of the group consisting of a torrification plant, a pyrolysis plant, a gasification plant, in particular a fixed bed gasifier, a fluidized bed gasifier, a entrained flow gasifier, a loop reactor and / or a fluidized bed gasifier.

[0020] A carrier gas or purge gas can be used as the gas stream to carry away the desorbed residues, for example, an inert gas, nitrogen, or a mixture thereof. Additionally or alternatively, a reaction gas can be used as the gas stream, which can react with the desorbed residues and / or the carbon product, such as water vapor, air, oxygen, a reducing or oxidizing agent, exhaust gases from combustion processes, such as internal combustion engines, or mixtures thereof.

[0021] The heating of the carbon product within the desorber can be allothermal, for example by external energy input, such as by electric heating elements, by firing or by heating gas; and / or autothermal, for example by partial oxidation of the carbon product (2) or partial oxidation of an additive.

[0022] The process according to the invention is generally suitable for purifying carbon products from which the residues to be removed are desorbable. Preferably, the process according to the invention is used to remove PAH residues, wherein the purified end product preferably contains less than 1000 mg / kg PAH based on the dry mass of the carbon product, preferably less than 600 mg / kg, preferably less than 300 mg / kg, preferably less than 100 mg / kg, preferably less than 50 mg / kg, preferably less than 10 mg / kg, preferably less than 6 mg / kg or 4 mg / kg or < 1 mg / kg.

[0023] Furthermore, it is preferred that the carbon product is introduced into the desorber to a maximum filling level of 75%, preferably to a maximum filling level of 50%, and preferably with a filling level of at least 25%. The filling level is the volume of the carbon product within the desorber divided by the internal volume of the desorber.

[0024] The carbon product can be turned and / or mixed several times during the residence time or during transport.

[0025] Furthermore, the present invention also relates to a method for producing a carbon product comprising the steps of: providing a carbon product, preferably from a thermochemical process, containing residues, in particular PAHs; removing residues according to a method according to the invention in order to obtain a residue-free or reduced carbon product.

[0026] The present invention also relates to a desorber for the desorption of residues from a carbon product, in particular according to a process according to the invention, or for the production of a carbon product, wherein the desorber preferably comprises: a residence volume into which a carbon product containing residues can be introduced, with an inlet for introducing the carbon product and an outlet for discharging the carbon product; heating means for heating the carbon product within the desorber to a temperature higher than 700°C, preferably between 700°C and 1500°C, so that the residues of the carbon product are desorbed; and a device for introducing a gas stream into the residence volume in order to remove at least a proportion of the desorbed residues from the carbon product by means of the gas stream and to discharge them from the desorber via a gas outlet.

[0027] According to the invention, the desorber can be operated in batch or continuous operation. For continuous operation, it is preferred to provide a transport device to transport the carbon product within the desorber, and preferably to transport the carbon product purified of residues to the outlet.

[0028] The heating medium can have at least one external heating sleeve, preferably at least one electrically operated heating sleeve.

[0029] The transport device can be, for example, a spiral conveyor unit.

[0030] Preferably, at least one temperature sensor is installed in the desorber, preferably at least one temperature sensor is installed in the core of the spiral conveying unit.

[0031] The temperature measured by the temperature sensor is preferably transmitted to a control unit, the control unit being preferably configured to control the temperature of the heating medium and / or the speed of the transport device.

[0032] Furthermore, the present invention also relates to a carbon product obtainable from the process according to the invention, wherein the carbon product preferably has less than 1000 mg PAH per kg based on the dry mass of the carbon product, preferably less than 600 mg / kg, preferably less than 300 mg / kg, preferably less than 100 mg / kg, preferably less than 50 mg / kg, preferably less than 10 mg / kg, preferably less than 6 mg / kg or 4 mg / kg or < 1 mg / kg.

[0033] For example, the carbon product can be charcoal. Preferably, the charcoal can have a dry mass content of 68 to 95%, preferably 75 to 93%, and particularly preferably 80 to 92% carbon, a dry mass content of 4 to 18%, preferably 5 to 13%, and particularly preferably 6 to 10% ash, a mass content of 20 to 50%, preferably 25 to 40%, and particularly preferably 28 to 35% water, and / or an internal surface area of ​​200 to 400 m² / g.

[0034] Definitions of terms

[0035] Desorption (from the Latin de-sorbere; sorbere: to absorb) refers specifically to the process by which atoms or molecules leave the surface of a solid (reverse process: adsorption) or pass from a liquid in which they were dissolved into the gas phase (reverse process: absorption). In the latter case, the process is also referred to as stripping. Desorption thus generally represents the reverse process of sorption. In order to desorb, the particle must possess or be supplied with sufficient energy to overcome the binding energy.

[0036] Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds consisting of at least two fused aromatic ring systems. Simple examples like naphthalene and fluorene have a planar structure, while others, such as benzo[c]phenanthrene, exhibit a helical structure (helicene). This helical structure results from the steric repulsion of the hydrogen atoms in the bay region. The simplest PAH is naphthalene, in which two benzene rings are fused via a common bond; these are also referred to as fused ring systems. Fluorene is also a PAH, as both rings are rigidly connected by an additional methylene unit. Polycyclic aromatic hydrocarbons (PAHs) comprise a class of hundreds of individual compounds.PAHs are typically formed when organic material is heated or burned under oxygen-deficient conditions (incomplete combustion), for example, during a thermochemical conversion process that produces a carbon product such as charcoal. Since PAHs are classified as partially toxic, large portions of these PAH residues should be removed from the carbon product to obtain a purified carbon product that can then be used in many applications.

[0037] A purge gas is generally an inert gas that is preferably passed through a process chamber as a continuous stream. Its purpose is twofold: firstly, to minimize unwanted and uncontrolled chemical reactions with any remaining substances; and secondly, or alternatively, to transport unwanted gases or substances out of the process chamber.

[0038] When the removal of residues is mentioned below, this means that at least some of these residues are removed, and not necessarily that the residues are removed 100%.

[0039] Brief description of the drawings

[0040] Preferred embodiments of the present invention are described in more detail below with reference to the figures. The figures show:

[0041] Figure 1 shows an exemplary overview of a gasification plant with a desorber according to the invention; and

[0042] Figure 2 shows a schematic cross-sectional view of an exemplary embodiment of a desorber in the form of a horizontal heated tube with a spiral conveyor arranged therein.

[0043] Detailed description of preferred embodiments

[0044] Figure 1 schematically shows a gasification plant 42 with a pyrolysis unit 40 and a downstream fluidized bed reactor 41 according to patent DE 10 2007 012452 B4. As briefly mentioned above, a gas and a carbon product, in the form of a solid, can be extracted from the fluidized bed reactor 41 and separated, for example, by means of a filter 43. The gas, purified of solids, is flammable and, after optional cooling and further purification, for example by means of a scrubber, can be used in a variety of ways. This flammable gas can, for example, be used to operate a gas engine, as schematically shown in Figure 1.

[0045] The solids separated in filter 43 are carbon-containing solids, i.e., a carbon product that may contain residues due to the manufacturing process, for example PAH residues.

[0046] A significant portion of these PAH residues can be removed by a device according to the invention, preferably to such an extent that known limit values ​​for PAH 16 of < 6 mg / kg or < 4 mg / kg dry material (DM) are met. According to the invention, the PAH separation is carried out by desorption, so that, for the sake of simplicity, the device according to the invention is also referred to as a desorber. In Fig. 1, the desorber 1 according to the invention is arranged below the filter, so that the desorber 1 forms part of a process plant, and a "fresh" carbon product is purified immediately. In other words, the desorber can be used "in-situ".

[0047] Alternatively, the desorber 1 according to the invention can also be used "ex-situ," for example, in conjunction with any container for a carbon product, essentially as a stand-alone post-treatment. In-situ use follows essentially the same operating principle as ex-situ use; however, the desorber 1 is preferably positioned directly at the point in the process where the carbon product is generated. In such an in-situ case, the "fresh" carbon product from the process is preferably preheated, so that the carbon product enters the desorber 1 at approximately 300°C, for example. This has the advantage, for instance, that the energy required to heat the desorber and the carbon product it contains can be reduced. Furthermore, the residence time of the carbon product within the desorber can also be reduced in in-situ use due to the preheated carbon product.

[0048] Fig. 2 shows a schematic cross-sectional view of an exemplary embodiment of a desorber 1 according to the invention. In this embodiment, charcoal, as an example of a carbon product, is purified according to the invention, i.e., PAHs adhering to the charcoal are removed. According to the invention, PAHs are desorbed by thermal action. This desorption takes place in a desorber 1, which, according to Fig. 2, is designed as a tubular reactor 1. A carbon product containing PAHs is introduced into the tubular reactor 1 via the inlet 11 and remains in the interior or volume of the tubular reactor 1 for a certain residence time in order to desorb the PAHs during this residence time. Subsequently, the purified carbon product is discharged from the tubular reactor 1 via an outlet 12.

[0049] Based on the thermal desorption of PAHs, the carbon product must be heated within the desorber 1, i.e., here within the tubular reactor 1. Generally, heating is achieved using heating elements, which can be implemented in a variety of ways according to the invention. In the illustrated embodiment, for example, six heating jackets 5 are attached outside the tubular reactor 1, which can be electrically operated, for instance. This is easy to design and also allows for precise and simple temperature control. Since the thermal energy is supplied externally, this embodiment is an example of an allothermal design. In process engineering, conversion processes involving an external heat supply are specifically referred to as allothermal.

[0050] The present invention is not limited to this particular allothermal embodiment and a person skilled in the art will understand that there are many ways to supply heat energy to the system from the outside, e.g. by means of a burner, gas burner, or simply by means of a hot gas, without being limited to this.

[0051] Furthermore, according to the invention, the energy supply for desorption is not limited to an external energy supply. Alternatively or additionally, energy from within, i.e., autothermal energy, can also be used to heat the carbon product within the desorber 1, for example by (partial) oxidation of the carbon product.

[0052] According to the invention, it is preferred that the carbon product to be purified remains in the desorber 1 for a defined residence time. A defined residence time is achieved, for example, by introducing the carbon product to be purified into the desorber 1 via an inlet 11, then transporting it within the desorber 1 by means of a transport means 6 until the purified carbon product is discharged via the outlet 12. In the embodiment shown in Fig. 2, a spiral conveyor unit 6 is installed inside the tubular reactor 1, so that the mass transport takes place along the reaction zone within the desorber 1. The spiral conveyor unit 6 is rotated, for example, by the motor M, which is arranged to the left outside the tubular reactor 1.

[0053] By combining this conveying unit 6 with an optional second upstream conveying unit that controls the amount of carbon product fed into the desorber 1 per unit of time, the mass flow rate, residence time, and fill level can be defined, i.e., fixed and / or changed. Preferably, the residence time depends on the temperature in the desorber 1. For an effective and economical system, it is preferred that the residence time be as short as possible. On the other hand, the residence time should be long enough to desorb the desired proportion of residual materials or PAHs. In general, with the desorber and the desorption process according to the invention, it is possible to purify carbon products to the desired degree of purity within a relatively short time, which makes the process according to the invention technically and economically applicable. Among other things, the residence time depends on the selected temperature in the desorber 1.A person skilled in the art will understand that higher temperatures require higher energy consumption but allow for shorter residence times. Therefore, a compromise between temperature and residence time is preferred. Typical residence times are, for example, > 2 min (e.g., at 950°C); preferably > 5 min (e.g., at 850°C); and preferably < 30 min (e.g., at 800°C).

[0054] Furthermore, it is preferred that the fill level within the desorber is < 100%, i.e., the quotient of the volume of the carbon product within the desorber 1 and the internal volume of the desorber. Preferably, the fill level is 25-75%; preferably approximately 50%.

[0055] Furthermore, it is preferred that the purification process within the desorber 1 takes place in an inert environment, which, for example, prevents structural changes to the carbon product. Alternatively, partial oxidation of the carbon product can also occur within the desorber 1, for example in an autothermal embodiment.

[0056] An inert environment is achieved, for example, by introducing a low-reactivity gas, such as nitrogen (N2).

[0057] With the aid of this introduced gas stream, it is also possible to transport the desorbed PAH from the desorber 1. In the embodiment shown in Fig. 2, this gas stream 3 is operated as a counter-current to the material stream. In other words, the carbon product 1 is transported from left to right by means of the spiral conveyor unit 6, whereas the gas stream 3 runs from right to left. However, a co-current flow of carbon product and gas stream is also possible. A batch operation is also possible according to the invention; that is, the desorber 1 is first filled with a carbon product to be purified, then the desorption process is carried out, and subsequently the purified carbon product is discharged from the desorber 1.

[0058] In Fig. 2 an optional filter 8 or filter candle 8 is shown at the gas outlet 4 to remove solid contaminants, such as coal dust, from the gas if necessary.

[0059] The introduced gas, hereinafter also referred to as transport gas, enables a clean separation of the solid and gas phases. Furthermore, by eliminating the need for additional oxidizing agents, the carbon content of the carbon product, e.g., charcoal, can be kept stable.

[0060] Since the desorption of PAHs depends essentially on temperature and residence time, it is preferred to monitor, control, and preferably regulate the ongoing process. In particular, for control purposes, the temperature is measured at at least one, preferably several, points within the desorber 1, and these measured temperature values ​​are then fed to a corresponding control mechanism. Accordingly, the temperature of the heating medium can then be increased, decreased, or kept constant. Additionally or alternatively, the residence time can also be controlled via the transport mechanism. For example, the rotational speed of the screw conveyor can be controlled in this way.

[0061] According to a preferred embodiment, at least one temperature sensor 7 is integrated into the screw conveyor core. For example, in Fig. 2, two temperature sensors 7 are shown near the two ends of the spiral screw conveyor. However, any number of temperature sensors 7 can be installed inside or outside the core of the spiral screw conveyor 6. Alternatively, a single temperature sensor 7 can be installed inside the core of the spiral screw conveyor 6 or at another location within the desorber. The arrangement of the at least one temperature sensor 7 has the advantage that this sensor is in a protected location and cannot be damaged by the conveyed material. A temperature sensor 7 can also be placed at the outlet of the reaction chamber (desorber), which then measures the temperature of the carbon product shortly before it is discharged from the desorber 1.

[0062] Initial test series showed that results below the detection limit can be achieved, i.e., PAHs could be removed to such an extent that a PAH residue is no longer easily detectable in the purified carbon product.

[0063] In this series of experiments, mass flows of 26 kgh were achieved. 1 successfully purified at temperatures above 700°C. Good PAH desorption has been shown to occur at temperatures between 700°C and 1500°C, preferably between 700°C and 950°C, and preferably between 800°C and 850°C.

[0064] To achieve better mixing and thus a uniform temperature distribution in the carbon product to be purified, it may also be preferable to attach additional blades or “displacers” to the conveying spiral 6, so that the carbon material 2 is not only transported transversely through the tubular reactor (1), but the carbon material is also mixed, so that different surfaces of the carbon material 2 repeatedly come into contact with the gas stream 3, and the desorbed PAH is well transported away.

[0065] Furthermore, the desorber (1) according to the invention can also be used to efficiently heat a carbon product to temperature in order to be activated or otherwise post-treated in a further process unit. It is also possible to continue the temperature treatment further; e.g.

[0066] Temperatures > 900°C..

[0067] Reference symbol list:

[0068] 1 container, desorber device, desorber, e.g. tubular reactor

[0069] 2 Carbon product 2' purified carbon product

[0070] 3 Gas flow, transport gas flow

[0071] 4 Gas outlet

[0072] 5 Heating agents

[0073] 6. Transport means or transport device, e.g. spiral conveyor unit; 7. Temperature sensor

[0074] 8 filters or filter cartridges

[0075] 11 Entrance

[0076] 12 Exit

[0077] 40 Pyrolysis unit 41 Fluidized bed reactor

[0078] 42 Gasification plant

[0079] 43 filters

[0080] M Motor for rotating the spiral conveyor unit

Claims

PATENT CLAIMS 1. A process for the desorption of residues from a carbon product, wherein the process comprises the following steps: Introducing a carbon product containing residues (2) into a desorber (1); Heating the carbon product (2) inside the desorber (1) to a temperature of at least 700°C, so that at least a proportion of the residual materials of the carbon product (2) is desorbed; Introducing a gas stream (3) into the desorber (1) such that the desorbed residues are removed from the carbon product (2) by means of the gas stream (3) and discharged from the desorber via a gas outlet (4); wherein the carbon product remains within the desorber (1) for a residence time in the desorber (1), and Discharge of the carbon product (2') freed from residues from the desorber (1).

2. The method of claim 1, wherein the carbon product (2) is located within the desorber (1) is heated to a temperature between 700°C and 1500°C, preferably to a temperature between 700°C and 1500°C. D C - 950 D C.

3. The method according to claim 1 or 2, wherein a residence time of the carbon product (2) is achieved in the desorber (1) in a batch operation or by continuous transport from introduction to discharge, wherein the residence time is preferably shorter than 20 min, preferably shorter than 10 min, preferably shorter than 5 min, preferably shorter than 2 min.

4. Method according to claim 1, 2 or 3, wherein the carbon product (2) is any C-containing substance, preferably coal of organic origin, from biomass, from wood, from plants, and / or charcoal.

5. A method according to any one of the preceding claims, wherein the carbon product (2) is fed to the desorber (1) from a thermochemical conversion system, wherein the thermochemical conversion system is one of the group consisting of a torrification plant, a pyrolysis plant, a gasification plant, in particular a fixed bed gasifier, a fluidized bed gasifier, a entrained flow gasifier, a loop reactor and / or a fluidized bed gasifier.

6. A method according to any of the preceding claims, wherein the gas stream (3) a. is a carrier gas or purge gas for the removal of the desorbed residues; such as an inert gas, N2 or a mixture thereof; and / or b. is a reaction gas that can react with the desorbed residues and / or the carbon product (2), such as water vapor, air, oxygen, a reducing or oxidizing agent, exhaust gases from combustion processes, such as internal combustion engines, or mixtures thereof.

7. Method according to any of the preceding claims, wherein the heating of the carbon product (2) within the desorber (1) is carried out a. allothermally, for example by external energy supply, for example by electric heating means, by firing or by heating gas; and / or b. autothermally, for example by partial oxidation of the carbon product (2) or partial oxidation of an additive.

8. A method according to any of the preceding claims, wherein the residual material is PAH and the purified end product has less than 1000 mg / kg PAH based on the dry mass, preferably less than 600 mg / kg, preferably less than 300 mg / kg, preferably less than 100 mg / kg, preferably less than 50 mg / kg, preferably less than 10 mg / kg, preferably less than 6 mg / kg respectively. 4mg / kg or < 1 mg / kg.

9. Method according to one of the preceding claims, wherein the carbon product (2) is introduced into the desorber to a maximum filling level of 75%, preferably to a maximum filling level of 50% and preferably with a filling level of at least 25%.

10. Method according to one of the preceding claims, wherein the carbon product is turned and / or mixed several times during the residence time or during transport.

11. A process for producing a carbon product comprising the steps of: a. Providing a carbon product, preferably from a thermochemical process, containing residues, in particular PAHs; b. Removing residues according to a process according to claims 1 to 7, to obtain a residue-free or reduced carbon product (2').

12. Desorber (1) for desorption of residues from a carbon product (2), in particular according to a method according to any one of claims 1 to 10, or for producing a carbon product, in particular according to claim 11, wherein the desorber (1) comprises: a. a residence volume into which a carbon product (2) containing residues can be introduced, with an inlet (11) for introducing the carbon product (2) and an outlet (12) for discharging the carbon product (2); b. heating medium (5) for heating the carbon product (2) within the desorber (1) to a temperature higher than 700°C, preferably between 700°C and 1500°C, so that the residues of the carbon product (2) are desorbed; c. a device for introducing a gas stream (3) into the residence volume in order to remove at least a proportion of the desorbed residues from the carbon product (2) by means of the gas stream (3) and to discharge them from the desorber (1) via a gas outlet (4); and d. optionally a transport device (6) for transporting the carbon product (2) within the desorber (1), and preferably for transporting the carbon product (2') purified of residues to the outlet (12).

13. Desorber according to claim 12, wherein the heating medium (5) has at least one external heating jacket, preferably at least one electrically operated heating jacket.

14. Desorber according to one of claims 12 or 13, wherein the transport device (6) is a spiral conveying unit (6).

15. Desorber according to one of claims 12 to 14, wherein at least one temperature sensor (7) is installed in the desorber (1), preferably in the core of the spiral conveying unit.

16. Desorber according to claim 15, wherein the temperature measured by the temperature sensor (7) is transmitted to a control unit and the control unit is configured to control the temperature of the heating medium (5) and / or the speed of the transport device (6).

17. Carbon product obtainable from the process according to claims 1 to 11, wherein the carbon product has less than 1000 mg PAH per kg based on the dry mass of the carbon product, preferably less than 600 mg / kg, preferably less than 300 mg / kg, preferably less than 100 mg / kg, preferably less than 50 mg / kg, preferably less than 10 mg / kg, preferably less than 6 mg / kg or 4 mg / kg or < 1 mg / kg.

18. Carbon product according to claim 17, wherein the carbon product is charcoal, wherein the charcoal has a. a dry mass content of 68 to 95%, preferably 75 to 93% and particularly preferably 80 to 92% carbon, b. a dry mass content of 4 to 18%, preferably 5 to 13% and particularly preferably 6 to 10% ash, c. a mass content of 20 to 50%, preferably 25 to 40% and particularly preferably 28 to 35% water, d. and an internal surface area of ​​200 to 400 m² 2 / g

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