EP2176378A1

EP2176378A1 - Pyrolysis method and pyrolyzer

Info

Publication number: EP2176378A1
Application number: EP08782807A
Authority: EP
Inventors: Walter Graf; Franz B. SCHÜGERL; Wolfgang Kromp; Emmerich Seidelberger
Original assignee: Universitaet Wien
Current assignee: Universitaet Wien
Priority date: 2007-08-09
Filing date: 2008-08-07
Publication date: 2010-04-21
Also published as: WO2009018595A1

Abstract

A method for the pyrolysis of a pyrolyzable material, particularly a biomass and organic waste products, the material to be pyrolyzed being fed to a pyrolyzer unit (3), the material to be pyrolyzed being pressed, heated and pyrolyzed in the pyrolyzer unit (3) in at least one pyrolysis zone (3') defined by two counter-rotating pressing means, at least one of the pressing means being configured as a heating means, characterized in that the two pressing means are configured as toothed rolls (5a, 5b) engaging in each other, that means for supporting the pressing means are provided, said means being configured as roll pairs (22), and that means for adjusting both a minimum distance and a maximum distance between the two pressing means are provided.

Description

Pyrolysis process and pyrolyzer

The invention relates to a pyrolysis process, in particular the production of oil by the so-called flash pyrolysis, and a pyrolyzer suitable for this purpose.

Pyrolysis is generally understood as a thermal cleavage of chemical compounds, whereby high temperatures cause bond breaking within large molecules. Mostly this happens under exclusion of oxygen (anaerobic) to prevent the combustion. Optionally, dehydrating or dehydrating agents are added during the process. Process parameters are, in addition to the temperature, the pressure, the heating time and possibly also the presence of catalysts.

The pyrolysis produces a primary pyrolysis gas and almost always solid residues such as coke or coal. Most of the primary pyrolysis gas is converted into an oil by (fractional) condensation. Non-condensable gas components must be disposed of or utilized for the generation of process heat.

Flash pyrolysis is often carried out in fluidized bed reactors. In this case, a sand bed is heated and swirled up by a fluidizing gas, resulting in liquid-like physical properties with regard to the heat transfer. In this fluidized bed, the input material is then finely ground (particle size in the order of one millimeter) supplied. As a result, the energy can be transferred very quickly from the fluidized bed to the input material and thus a prerequisite for the flash pyrolysis can be fulfilled.

The disadvantage of this method is that the feed must be crushed necessarily to a very small particle size and that the fluidizing gas must be heated cyclically and cooled again.

A possible remedy for this is an ablative realization of flash pyrolysis. In this case, for example, wood is fed to a rapidly rotating, about 650 ° C hot disk, where it evaporates at about 475 ° C. This results in heating rates of 10000C / s to 100000C / s (Bridgewater, "Biomass, Pyrolysis, Liquids, Upgrading and Utilization", page 21, 1991). This principle has subsequently been realized in various designs, such as those summarized by Bridgewater and Peacock (see Bridgewater and Peacock, Fast pyrolysis process for biomass, in Renewable & Sustainable Energy Reviews 4, 2000, 1-73). These plants described are complicated throughout and require the crushing of the entry material, which implies an energy-consuming additional process.

Based on these experiences, DE 103 45 842 A1 has disclosed a method based on a rotating heated disk against which biomass is forced under pressure, which very quickly melts and evaporates in this process in accordance with the flash pyrolysis condition. Essential in this method are means for guiding or supplying the biomass to the rotating hot disk. A particularly advantageous embodiment is described in which a revolver drum rotating relative to the heated disk is provided, which serves as a means for guiding the biomass, and conveying means connected to this guiding means, which apply the necessary pressure to the biomass against the hot disk to squeeze. At a fixed point, the filling of the guide means by an arrangement for refilling the guide means of biomass is performed by a magazine. For example, this magazine is designed to compress the biomass in order to introduce the compressed biomass into the guide means.

A disadvantage of this method is the high mechanical complexity for guiding, conveying and Vorverpressen the biomass, the number of necessary drives and the electrical or electronic effort to control the processes. This process was designed primarily for processing woodchips. It may even be suitable for the utilization of planks (for example whole railway sleepers).

However, for economic reasons (increasing wood prices), the object of the present invention is not primarily the utilization of wood, but the utilization of other organic residues, such as wood. Straw, reed or corncob, for which the method known from DE 103 45 842 A1 is too expensive.

Another object of the subject invention is the utilization of areal waste such as e.g. Car tires without preliminary processes, which is not possible with the method known from DE 103 45 842 Al.

Since the main application of the subject invention on the utilization of low energy density entry materials, the subject method must be substantially simplified over that described above, so that an economic representation of much smaller units is possible. On the device side, the heated disk and the means for guiding and compressing should be replaced by a simpler mechanical unit.

Devices and methods for pyrolysis of pyrolyzable material are also known from WO 2006/23662 and US 6,623,602.

The object is achieved with regard to the method by the features of claim 1 and with respect to the device by the features of claim 14.

The inventive method for pyrolysis of a pyrolyzable material, in particular of biomass and organic waste, wherein the material to be pyrolyzed is fed to a Pyrolysatoreinheit, characterized in that the material to be pyrolyzed in the Pyrolysatoreinheit pressed in at least one defined by two counter-pressing means Pyrolysierzone, is heated and pyrolyzed, wherein the two pressing means are formed as intermeshing toothed rollers, means for storing the pressing means are provided, which means are formed as pairs of rollers and that means are provided both for setting a minimum distance and a maximum distance between the two pressing means.

The entry material can thus be fed without pressure, since the pressure is generated by the counter-rotating pressing means.

The apparatus for carrying out the method comprises means for feeding the material to be pyrolyzed, a pyrolyzer unit comprising at least two counter-rotating pressing means, at least one of which is designed as heating means defining a pyrolysis zone, means for driving at least one of the two pressing means, means for heating the at least one pressing means designed as heating means, means for regulating pressure and means for collecting the pyrolysis products and is characterized in that the two pressing means are designed as intermeshing toothed rollers, that means for supporting the pressing means are provided, which means are designed as pairs of rollers and in that means are provided both for setting a minimum distance and a maximum distance between the two pressing means.

Further aspects and advantageous improvements of the invention are specified in the subclaims.

In addition, the invention can be advantageously designed in the following way: - The exhaust gases of the heating element can be at least partially discharged.

- An unexhausted part of the exhaust gases can be used as a purge gas.

- An unexcelled part of the exhaust gases of the heating element can be processed with primary pyrolysis gases.

All exhaust gases of the heating element can be discharged and processed separately from primary pyrolysis gases.

The invention will be described with reference to preferred embodiments in the following with reference to the drawings. In the figures show:

1 is a highly schematic representation of a preferred exemplary embodiment of an inventively designed pyrolysis,

2 is a detailed view of the pyrolyzer unit of the preferred embodiment of FIG. 1,

3 shows a schematic representation of the torques and forces occurring in the preferred embodiment,

4 is a highly schematic side view of the rollers with spacers arranged thereon,

5 is a highly schematic view of rollers in concave-convex shape,

Fig. 6 is a schematic representation of the supply of material for granular material, e.g. Straw, and

7 shows a schematic representation of the pyrolysis unit with separate exhaust gas and pyrolysis gas zones.

FIG. 1 shows an overview of the individual functional groups of a preferred exemplary embodiment of a pyrolyzer according to the subject invention. The subject invention relates to a pyrolyzer 1 and a flash pyrolysis process in which the feedstocks decompose very rapidly, that is, on the order of one to two seconds at a temperature of typically 550 ° C - 650 ° C, to a primary pyrolysis gas and within a similar period of time to be condensed into an oil. However, the invention can also be used for any other pyrolysis process in which the process parameters deviate from the typical values of flash pyrolysis.

The process according to the invention and the device according to the invention are suitable for the pyrolysis of substances in various forms, e.g. liquid, granular, elongated and flat feedstock. In particular, the method and apparatus of the invention are suitable for pyrolysis of biomass and organic wastes, e.g. natural or synthetic oligomers, natural or synthetic polymers, lignocellulosic raw materials, rubber, plastics and mixtures of these substances, manure, sludge, in particular sewage sludge, organic residues, industrial wood, timber and car tires.

The inventively provided Pyrolysator 1 has a material metering unit 2, which may possibly comprise a reservoir not shown. By means of the material metering unit 2, the actual pyrolyzer unit 3 is fed in a controlled manner with a pyrolysis zone 3 'to the material to be pyrolyzed. By an external drive 4 rollers 5 of the pyrolysis unit 3 are driven speed controlled. In the preferred embodiment, one of the rollers 5, which is designed as a heating roller 5a, heated by a heating element 6, which can be fed with pyrolysis products. In a preferred embodiment, the exhaust gases of this heating element 6 are passed through the second roller 5b in order to make maximum use of the waste gas heat. The resulting in the pyrolysis charcoal is collected in a separate receptacle 7. The primary pyrolysis gases are condensed in a condenser 8. The condensable fractions of the primary pyrolysis gas are collected in an oil collector 9.

The non-condensable fractions of the primary pyrolysis gas are sucked off in the preferred embodiment by means of a suction pump 10. The suction power of the pump 10 is controlled, wherein the pressure in the Pyrolysatoreinheit 3 is the controlled variable, which is measured by means of a pressure sensor 11. The temperature in the pyrolyzer 1 is measured with one or more temperature sensors 12.

Depending on the requirements, further temperature sensors 12 can be arranged in the entire pyrolyser 1. For example, in the illustrated arrangement, the temperature of the non-condensable pyrolysis gas in the cooler 8 measured. All measurements, controls and controls are performed by a control unit 13.

A further advantageous embodiment can provide a temperature control by controlling the supply of the input material, which eliminates a control stage and the pyrolyzer 1 can be operated both simpler and more economical.

The pyrolysis takes place in principle with the exclusion of air, that is, the two rollers 5 are in the Pyrolysatoreinheit 3 under exclusion of air. The same applies if the heating of the rollers 5 is effected by a heating element 6 located in the interior of the rollers 5, in which a fuel is burned. In order to ensure the function of the heating element 6, therefore, the heating element 6 in addition to the fuel and air in stoichiometric ratio must be supplied. Thus, for reasons of clarity not shown means for controlling the fuel and the air supply necessary.

The resulting during operation of the heating element 6 exhaust gases can be either at least partially discharged and used in particular instead of an inert gas as a sealing gas as described below, which significantly reduces the use of an inert gas and the associated design and maintenance costs. This is particularly advantageous because any hot gases can be used.

The processing of the exhaust gases of the heating element 6 together with by-products of the pyrolysis is possible, which facilitates the sealing of the Pyrolysatoreinheit 3. This is especially possible when using a heating gas whose combustion products do not contain water vapor, e.g. Carbon monoxide (CO).

A third possibility for handling the exhaust gases of the heating element 6 is shown in FIG. 7 in a section through the pyrolyzer unit 3. The heating element 6 is arranged in this embodiment in a U-shaped tube 27 which extends through both the interior of the heating roller 5a as well as the transport roller 5b. In the region of the rollers 5a and 5b, cooling fins 28 are arranged in order to remove the heat of the heating element 6 in the targeted manner in the area of the rollers 5a, 5b. A combustion chamber of the heating element 6 is thus spatially completely separated from the pyrolysis zone 3 'and thus also the resulting heating and pyrolysis gases. The gas pressure inside the Pyrolysatoreinheit 3 is held by external means such as the aforementioned barrier or inert gas, on the one hand to prevent the escape of toxic gases, on the other hand, to avoid the ingress of oxygen, which would lead to a burning of the pyrolysis. These means must reduce the resulting from the formation of primary pyrolysis gases pressure and consist of at least one pressure gauge 11 and a device for pressure control. This includes, for example, the induced draft pump 10 for exhausting the pyrolysis gases and a corresponding control unit, which may be part of the control unit 13.

To carry out the process according to the invention, means for collecting the pyrolysis products are expediently provided. These are preferably designed so that solids are separated as a result of gravity or by means of cyclones of the liquid or gaseous pyrolysis. Furthermore, a cooler 8 arranged downstream of the pyrolysis unit 3 is provided in which the primary pyrolysis gases may also be fractionally condensed and solids which are still in the primary pyrolysis gas are separated off. The resulting pyrolysis oil is collected in the container 9 and discharged the non-condensable gas components.

By the pressure control and by suitable design of the Pyrolysatoreinheit 3 and the container 9 for collecting the condensable pyrolysis must be taken to ensure that the residence time of the primary pyrolysis until further processing to a period of about 0.5 to about 10 seconds, preferably less than 5 seconds, more preferably less than 2 seconds. Preferably, the residence time is adjusted based on the rotational speed of the pressing means 5.

The material entry takes place in the preferred embodiment from above by a suitable material metering unit 2, which regulates the amount of material introduced, but could in principle also be made from any other side as required. The execution of the material metering unit 2 is carried out according to the properties and the shape of the entry material, depending on whether the entry is liquid, granular, oblong or flat, and may be carried out in the form of any other material conveyor.

The task of the material metering unit 2 is to supply as much material as possible, as can be processed in the Pyrolysatoreinheit 3. This quantity is determined by the heat output of the heating element 6 and the melting or gasification heat required per unit of quantity. Another object of the material metering unit 2 is to heat the material supply in the reservoir of the Pyrolysatoreinheit 3 thermally foreclosed, so that the stockpiled material does not prematurely thermally decompose or even burned in unfavorable cases. Likewise, the material metering unit 2 must ensure maximum gas tightness.

As raw material for the pyrolysis natural or synthetic oligomers, natural or synthetic polymers, lignocellulosic raw materials, rubber, plastic or mixtures of these substances, liquid manure, sludge, especially sewage sludge, organic residues, but also difficult to dispose of materials such as coated, varnished or glazed or in other ways, surface-treated wood-based materials, industrial and construction timber and car tires are used.

The pyrolyzer 1 is controlled by the control unit 13. The task of this control unit 13 is to monitor the operating parameters or regulate 2x1. The most important parameters are the temperature of the heating roller 5a, the speed of the heating roller 5a and the transport roller 5b, the distance between the two rollers 5 to each other during the pyrolysis process, the material dosage and the gas pressure.

The temperature can be adjusted on the one hand by controlling the energy supply to the heating element 6 (eg gas supply to the gas burner), on the other hand, in a preferred embodiment, the control of the heating can be omitted and the energy supply can be kept constant, but the amount of material supplied via the above-described material metering unit 2 be controlled as a coolant so that the temperature remains constant.

The temperature profile along the Heizwalzenumfanges should be controlled in each case so that after the hot zone, the roll surface is cooled by the necessary heat of fusion and is heated again in the course of rotation.

The necessary torque is thus obtained by the control to a predetermined speed from the pressure necessary for the pyrolysis. The pressure exerted is thus limited only by the dimensioning of the drive and the mechanical arrangement. The speed of the rollers 5 is controlled so that, for example, according to the conditions of flash pyrolysis, the time ΔT _f i of passage of the feed through the melting or gasification zone (heating time) does not exceed a certain process time (eg one second) , Assuming that, for example, a rotation by an angle α of the rollers 5 is necessary, this results, for example, for α = 6 °, a speed N of one revolution per minute: (1) N = α / (6 * ΔT _fl ) [l / min].

However, the use of the invention is not limited to the conditions of flash pyrolysis. The heating time and according to the above formula the speed can be variably adjusted within wide limits with a certain mechanical dimensioning by the means for control. The maximum possible speed depends only on the dimensioning of the drive 4, that is, the drive power P and the maximum applied torque M:

(2) P = (2 * π * N / 60) * M [W].

The speed control consists of means for measuring the speed, in the preferred embodiment of a pulse generator, the drive 4 and the control unit 13th

The maximum drive torque of the drive 4 must be dimensioned so that the resulting during the drive of the rollers 5 resistive torque can be safely overcome. This moment of resistance depends on the maximum contact pressure to be exerted, the nature of the input material, the roll surface and the roll spacing. By specifying a minimum roll distance of this resistance moment and thus also the contact pressure is limited. For proper operation of the arrangement must therefore be ensured in a suitable manner that a certain minimum distance between the rollers 5 is maintained. In a preferred embodiment, spacer rings 23, as can be seen in FIG. 4, are provided for this purpose, but suitably positioned rollers could also be provided.

By crushing the material to be pyrolyzed, on the other hand, the rollers 5 may be forced apart. Therefore, it must be ensured in a suitable manner for a maximum distance between the two rollers 5, so that the entry material in the hot zone between the two rollers 5 is securely melted and gasified. This maximum distance depends only on the type or shape of the entry material.

The means for limiting the maximum distance consist in the preferred embodiment of pairs of rollers 22, which must absorb the horizontal forces in the preferred embodiment and will be described in more detail with reference to FIGS. 2 and 3. The position of these roller pairs 22 with respect to the roller position can be made adjustable. However, in the preferred embodiment only the position of that pair of rollers 22 are made adjustable, which receives the lateral forces of the indirectly driven roller 5b.

FIG. 2 shows a detailed representation of the pyrolyzer unit 3 of the exemplary embodiment illustrated in FIG. 1 of a pyrolyzer 1 configured according to the invention.

Via an opening 20, the material is supplied from the metering unit 2. The material passes in the preferred embodiment on a transport roller 5b, but could also be fed directly to the hot zone between the two rollers 5 in elongated or planar entrance materials. The heating roller 5a is driven in the preferred embodiment via a matching gear pair 21, which in turn is driven by the external controlled drive 4. The position of the drive 4 along the calf circumference is arbitrary and determined only by mechanical requirements. In principle, the transport roller 5b or both rollers 5 could be driven together. The latter is particularly necessary if the two rollers 5 are not designed as a toothed rollers as in the preferred embodiment.

In principle, the heating roller 5 a could also be heated in some other way (for example by a heat exchanger or by supplying an externally heated, gaseous heat transfer medium ). If the heating roller 5a is e.g. Indirectly heated by a gaseous heat transfer medium, the surface should be as large as possible in the interior of the heating roller 5a to improve the heat transfer. The transporting roller 5b is also hollow in the preferred embodiment to allow passage of the residual heat accumulating in the heating roller 5a (e.g., in the form of exhaust gases of the heating element 6). Preference is given to the pyrolysis products used for the heating, non-condensable pyrolysis gases or coal. The heating roller 5a is heated by the heating element 6 from the inside to the extent that the desired temperature is established on the surface of the heating roller 5a. The temperature can be up to about 1000 ° C. In special applications, for example for special input materials, it may also be necessary to heat both rolls 5 directly. The rollers 5 are made of a suitable refractory material, e.g. made of a corrosion-resistant steel, ceramic or a sintered material.

According to the present invention, both rollers 5 are designed as intermeshing, preferably cylindrical, toothed rollers. Depending on the nature of the input material, however, the roll surface can be structured as desired, for example by Nubs, mandrels or by radially extending grooves. The teeth of the toothed rollers could also be interrupted by radially extending grooves. The rollers 5 can also deviate from a cylindrical shape in order, for example, to adapt to the shape of the additive (eg car tires). Thus, for example, the rollers 5 can also be designed so that one roller 5 is convex and the other roller 5 is concave, as shown in highly schematic form in FIG.

The rolls can be formed depending on the entry material so that the entry material is well recorded and a dome formation and a Leidenfrost effect can be avoided.

One of the two rollers 5 is rotated by suitable drive means 4 in rotation, while the second roller 5 is driven in a preferred embodiment indirectly via the first roller 5 and thereby rotated in the opposite direction. The second roller 5 can be driven by the same drive 4 as the first roller 5 with special requirements or execution of the roller surface, but this is not necessary because the rollers 5 are designed as intermeshing toothed rollers. The drive 4 consists in the preferred embodiment of at least one, rotatably mounted on an axis, to the toothed rollers matching gear 21 which is driven by a variable speed motor. However, the drive of the rollers 5 can also take place in any other suitable form, for example by a directly engaging on the rollers 5 chain drive.

The execution of the rollers 5 as toothed rollers fulfills two functions. First, the material to be picked is well grasped by the transporting roller 5b and transported through the melting or gasification zone between the two rollers 5 in a predetermined period of time determined by the set number of revolutions of the rollers 5. Second, the entry material is squeezed in the melting or gasification zone and thus applied the necessary pressure for pyrolysis. The tooth depth is determined by the nature of the input materials (e.g., grain size).

In principle, the pyrolyzer unit 3 could also consist of several cascaded pairs of rollers in another embodiment. The above considerations apply analogously to each pair of rollers. This could be necessary in particular if the material to be picked can not be completely melted or gasified in one step due to its thickness (eg car tires). The capacity of the pyrolyzer unit 3 depends primarily on the heat of fusion or gasification provided by the heating element 6 (heating power minus thermal losses due to convection and radiation), but for feedstocks such as straw it may also be limited by other factors, as shown in FIG. 6 shown schematically. These factors are the tooth depth, the cross section of the feed channel 25 between the material metering unit 2 and the transport roller 5b and a distance d between the feed channel 25 and the transport roller 5b. These parameters have to be optimally optimized so that they do not have a capacity-limiting effect or that a backlog of the input material can be avoided. An upper housing part 26 of the Pyrolysatoreinheit 3 is advantageously carried out in isolation to improve the thermal decoupling of the Pyrolysatoreinheit 3 of the material metering unit 2.

Depending on the crop, it may be necessary to clean the rollers 5 by suitable means to ensure a uniform heat transfer to the crop. If solid residues stick to the rollers 5, this could lead to disturbances of the pyrolysis and malfunction of the system. These means may for example consist of steel brushes.

The two rollers 5 are supported by a plurality of roller pairs 22 which receive the occurring horizontal and vertical forces, the number of roller pairs 22 and their position being determined by mechanical requirements. The pairs of rollers 22 may be arranged arbitrarily over the roll circumference. In the preferred embodiment shown in Fig. 2 take two pairs of rollers 22, the vertical forces, while another two pairs of rollers 22 absorb the horizontal forces. For special requirements (for example with variable setting of the minimum roll spacing), further pairs of rolls 22 could be arranged.

In the preferred embodiment, the necessary minimum distance between the two rolls is made by spacer rings 23. This is shown schematically in FIG.

The roller temperature can be determined by a further temperature sensor 12. The resulting from the pyrolysis charcoal is discharged through an opening 24.

In Fig. 3, the torque and forces occurring in the preferred embodiment are shown in highly schematic form. Basically, depending on which quadrants (Ql, Q2, Q3) along the calf circumference the position of the drive is selected, different cases are conceivable: 1st drive at the position Ql

By the torque Ml of the drive, the heating roller 5a is driven in the specified direction of rotation in the preferred embodiment. This creates a horizontal force Fl, which presses the heating roller 5a against the transport roller 5b. A rectified by the moment of resistance M3 of the heat roller 5 a bearing roller pair 22 resulting horizontal force F3. Fl and F3 thus press the heating roller 5a and the transport roller 5b against each other and thus support the necessary for the pyrolysis contact pressure. The pair of rollers 22 in position Ql remains almost free of forces.

2. Drive at position Q2

In this case, the heating roller 5a is drawn by the drive at the

Direction of rotation pushed upwards.

3. Drive at position Q3

In this case, in the indicated direction of rotation, the heating roller 5a against the

Roller pair 22 at the position Q2 and pushed away from the transport roller 5b.

The pairs of rollers 22 result from the high temperature and the consequent impossibility of directing the rollers 5 directly e.g. Store with a ball bearing as ball bearings are not specified for the high temperatures that occur. Therefore, an indirect storage by suitable bearings is necessary. Preferably, these bearings consist of roll tuples (in the simplest case said pairs of rolls 22) which must accommodate the horizontal and vertical forces (e.g., roll weight) that occur. At the roll position, the surface of the respective roller 5 is of course made round. By the rotation of the rollers 5 against each other, the introduced entry material is squeezed and thus generates horizontal forces. The crushing of the material entry in conjunction with the temperature of about 600-650 ° C then leads to the pyrolysis of the material. The pressure necessary for the pyrolysis determines the torque to be applied via the drive means 4, 21. It ultimately depends on the material to be processed and the resulting conditions, which drive position is given preference.

The heating roller 5 a drives in the preferred embodiment, the transport roller 5 b and is pressed in the assumed direction of rotation by the moment of resistance of the transport roller 5 b upwards (F2). Consequently, even in the cases where the drive is located in position Q2 and Q3, a supporting pair of rollers 22 at the position Ql necessary. F2 is opposite to the roll weight, which leads to a relief of the roller pair 22 at the position Q3 (F7). Thus, if the heating roller 5a is driven by the position Ql, the pair of rollers Q2 is free of forces and the roller pair 22 is relieved at the position Q3. In other words, this means that the thermally most loaded roller pairs 22 are mechanically relieved.

Between the heating and transport roller 5 a, 5 b acts a friction torque Mr, which is caused by the contact pressure necessary for the pyrolysis. In case 1 (drive at position Ql), the contact pressure and thus the friction torque are amplified by the drive. This results in a positive feedback, which can lead to mechanical blockages in unfavorable cases.

To avoid such blockages must be ensured by suitable means a minimum distance and thus a maximum friction torque between the two rollers, which depends essentially on the material to be processed. In the preferred embodiment, these means consist of the already mentioned spacer rings 23 which are positioned at the roll ends. But it could also be arranged additional pairs of rollers 22 between the rollers 5. Alternatively, it is also possible to change the drive position to Q2 or Q3.

Another way to reduce the risk of blockages in the case of a drive at the position Ql, Fig. 2 can be seen. The driving gears 21 are not located exactly above the heating roller 5 a, but at an angle ß to the transport roller 5 b. The angle β is preferably between 0 ° and 90 °, the angle range between 15 ° and 25 ° being particularly preferred. The circumferential force exerted by the drive therefore acts only reduced in the direction of the transport roller 5b.

The drive torque acting on the transport roller 5b via the heat roller 5a causes a vertical force F4 with which the transport roller 5b is pressed against the roller pair 22 at the position Q3 '. This vertical force is identical in magnitude to F2, but acts in the opposite direction, ie in the direction of gravity. The roller pair 22 at the position Q3 'is thus much more heavily loaded than the roller pair 22 at the position Q3.

The provision according to the invention for supporting the rollers by pairs of rollers and by the means provided for setting a minimum distance as well as a maximum distance between the two rollers ensures that the distance between the rollers automatically adapts to the thickness of the material to be pyrolyzed. Thus, the pressure exerted by the rolls is substantially independent of the thickness of the furnish and its respective structure. Also, the rolling resistance of the rollers and thus the corresponding proportion of the drive due to the inventive concept is independent of thermal expansion occurring.

Claims

Claims:

A process for pyrolysis of a pyrolyzable material, in particular of biomass and organic wastes, wherein the material to be pyrolyzed is fed to a pyrolyzer unit (3) and the material to be pyrolyzed in the pyrolyzer unit (3) in at least one counter-pressing means, at least one the pressing means is designed as a heating means, defined pyrolysis (3 ') is pressed, heated and pyrolyzed, characterized in that the two pressing means as intermeshing toothed rollers (5a, 5b) are formed, that means for storing the pressing means are provided, which means as Roller pairs (22) are formed and that means are provided both for setting a minimum distance and a maximum distance between the two pressing means.

2. The method according to claim 1, characterized in that the at least one heating means in the form of a heating element (6) is designed for direct heating.

3. The method according to claim 2, characterized in that in the heating element (6) by-products of pyrolysis, in particular non-condensable gases and coal, are utilized as heating fuels.

4. The method according to any one of claims 2 or 3, characterized in that the temperature at constant fuel supply to the heating element (6) is regulated by the supply amount of the insertion material.

5. The method according to any one of claims 2 to 4, characterized in that the surface temperature of the at least one heating means between 300 ° C and 1000 ° C, preferably between 400 ° C and 800 ° C, more preferably between 500 ° C and 700 ° C. , is advantageously between 55O ⁰ C and 650 ° C.

6. The method according to any one of the preceding claims, characterized in that the residence time of primary pyrolysis until further processing to a period of about 0.5 to about 10 seconds, preferably less than 5 seconds, more preferably less than 2 seconds is set.

7. The method according to claim 6, characterized in that the dwell time is adjusted based on the rotational speed of the pressing means.

8. The method according to any one of the preceding claims, characterized in that the rotational speed of the pressing means is regulated independently of the applied torque.

9. The method according to any one of the preceding claims, characterized in that due to the means for both setting a minimum distance and a maximum distance between the two pressing means, the distance of the pressing means automatically adjusts each other to the thickness of the material to be pyrolyzed.

10. The method according to any one of the preceding claims, characterized in that only one of the two pressing means is driven.

11. The method according to any one of the preceding claims, characterized in that both the rotation of the pressing means and the pressure on the material to be pyrolyzed material is accomplished only by a single drive.

12. Apparatus for carrying out the method according to one of the preceding claims, comprising

Means (2) for feeding the material to be pyrolyzed,

A pyrolyzer unit (3) which comprises at least two counter-rotating pressing means (5, 5a, 5b), of which pressing means at least one is designed as heating means, which define a pyrolysis zone (3 '),

Means (4, 21) for driving at least one of the two pressing means,

Means (6) for heating the at least one pressing means designed as heating means,

- means for pressure control, and

- means for collecting the pyrolysis products, characterized in that the two pressing means (5a, 5b) are formed as intermeshing toothed rollers that means for storing the pressing means are provided, which means are formed as pairs of rollers (22) and that means for both adjusting a Minimum distance and a maximum distance between the two pressing means are provided.

13. The apparatus according to claim 12, characterized in that as means for driving at least one in the or the pressing means cross-gear (21) or one or the pressing means driving chain drive is provided.

14. The apparatus according to claim 13, characterized in that the gear (21) is arranged with respect to the center of the toothed roller to be driven and on the vertical at an angle ß, for which applies 0 ° <ß <90 °, preferably 10 ° <ß <45 °, more preferably 15 ° <β <25 °.

15. The device according to any one of claims 12 to 14, characterized in that at least designed as a heating medium pressing means is designed to be hollow inside.

16. The apparatus according to claim 15, characterized in that means are provided for direct or indirect heating of the pressing means designed as a heating medium in the cavity.

17. The apparatus according to claim 16, characterized in that the heating means is designed as a heating element (6) for direct heating.

Device according to claim 17, characterized in that the heating element (6) has an exhaust gas outlet (27) separate from the pyrolyzer inlet (3).

19. The device according to any one of claims 12 to 18, characterized in that the surface temperature of the pressing means designed as a heating medium between 300 ⁰ C and 1000 ⁰ C, preferably between 400 ⁰ C and 800 ⁰ C, more preferably between 500 ⁰ C and 700 ⁰ C, is advantageous between 55O ⁰ C and 650 ° C.

20. Device according to one of claims 12 to 19, characterized in that the means for setting a minimum and / or maximum distance as Rollentupem with at least two rollers (22) are formed.

21. Device according to one of claims 12 to 20, characterized in that as means for setting a minimum distance spacer rings (23) are provided.

22. The apparatus according to claim 21, characterized in that the spacer rings (23) are positioned at the roll ends.

23. Device according to one of claims 12 to 22, characterized in that the device (1) is designed to be airtight.

24. Device according to one of claims 12 to 23, characterized in that the rotational speed of the pressing means is regulated independently of the applied torque.

25. Device according to one of claims 12 to 24, characterized in that the means for collecting the pyrolysis products comprise means for fractionating the gaseous pyrolysis products.

26. Device according to one of claims 12 to 25, characterized in that the drive means (4, 21) is designed to drive only one of the two pressing means.

27. Device according to one of claims 12 to 26, characterized in that the rotation of the pressing means (5, 5a, 5b) and the generation of the contact pressure on the material to be pyrolyzed is accomplished only by a single drive means.

28. The device according to any one of claims 12 to 27, characterized in that due to the means for both setting a minimum distance and a maximum distance between the two pressing means, the distance of the pressing means automatically adjusts each other to the thickness of the material to be pyrolyzed.