WO2018133905A1 - Device and method for treating biomass - Google Patents

Abstract

The present invention relates to a method for treating biomass in a heating plant, in which method the biomass (B) is fed in batches to a fuel dryer (2) and is dried therein by circulation with continuously fed process air (L) and, after drying has taken place, is discharged from the fuel dryer (2). Here, the following method sequence is realized: the process air (L) flowing through the fuel dryer (2) is heated, upstream of the fuel dryer (2), by means of a heating medium in a heat exchanger, and then the process air (L) that has been humidified in the fuel dryer (2) is discharged from the fuel dryer (2), and thereafter the circulation with process air (L) is performed, which ends after a target humidity of the biomass (B) situated in the fuel dryer or of the discharged process air (L) is attained.

Description

 Device and method for the treatment of biomass

The invention relates to a method for processing biomass for use in a heating system, in which the biomass is supplied in batches to a fuel dryer and is dried therein by circulating with process air. The biomass is pressed after removal from the fuel dryer in fittings. The invention also relates to a device for processing biomass.

Biomass: Organic substances of biogenic, non-fossil type for energy use, for example for use in biomass heating systems.

According to the definition of the Federal Association of Agricultural Trade Cooperatives e.V .: biomass heating systems. Kassel, 2008, p. 3, the energy-related biomass term covers animal and plant products that can be used for the production of heating energy, electrical energy and as fuels. Here, the biomass term refers exclusively to animal and vegetable, but not to microbial substances. Moreover, within the animal and plant substances it only includes substances that can be utilized in energy technology.

In the context of the described invention, biomass is an energy source of phytoplankton and zoom. This also includes phytate and by-product derived products and by-products, residues and wastes whose energy content originates from phytoplankton and zoomasse.

Economically interesting is the generation of heat from bioenergy, which is promoted in Germany, for example, by the Renewable Energy Heat Act (EEWärmeG). This applies above all to the use of biomass for pellet heating systems. A large amount of biomass accumulates in the form of horse manure mixed with sawdust and straw in horse farms. Keeping horses, especially for breeding and recreational sports, has become an important, if little noticed, economic factor worldwide and in Germany as well. The number of alone in

Germany for the purposes mentioned horses and ponies is estimated at about 1 million animals. The total turnover of this branch of industry in Germany is around € 6 billion annually. Approximately 57 m ^{3 of} horse manure are produced per horse per year (approx. 25 kg fuel / horse per day), whereby litter in the form of straw or sawdust is taken into account. The calorific value of horse manure is interesting and noteworthy. Thus, when burning 1 kg horse manure 3.5 to 4.0 kWh can be obtained. The calorific value of 1 kg of horse manure in a form suitable for burning, dried form is roughly comparable to the calorific value of 200 to 300 ml of fuel oil.

At dunging out of stables for pets, such as horses, animal manure or horse dung falls along with the respective bedding material for the animals, so for example straw or sawdust also mixed with food leftovers, such as hay as a mixture.

The pellets obtained from this are suitable for filling CHPs (combined heat and power plants), which in turn generate electricity and produce heating heat.

An introduction to the basics, techniques and procedures for energy production from biomass is given in KALTSCHMITT, M; HARTMANN, H, HOFBAUER, H; Energy from biomass. Basics, techniques and procedures. 2nd Edition. Berlin Heidelberg: Springer-Verlag, 2009, pp. 314-332. To find ISBN 978-3-540-85094-6. Described are for drying the biomass u.a. Catcher or box dryer with a regulated recirculation. Such systems are widespread, but build very voluminous and require a complex seal for recirculation.

An apparatus and method for the production of pellets of horse manure obtained biomass is already disclosed in DE 10 2006 006 701 B3. A suitably suitable heating system and method for operating a heating system, in particular using horse dung, is published in DE 102 26 538 A1. From this, the device for the treatment of biomass published from WO 2012/152248 A2 developed from the state of the art. The special feature here was the idea to cool process air before it is fed to the fuel dryer with a refrigerant in a heat exchanger, during which process air is removed from the process air by condensation. However, before the process air is fed to the dryer, it is still heated. Such dried and warmed process air would relatively quickly withdraw the unwanted moisture and dry it when they meet with the biomass in the fuel dryer. Another step towards a more compact design with controlled recirculation is disclosed in WO 2012/059075 A2. There, a drying drum with internal rotor for drying and crushing the biomass is provided.

However, to be operated in these two devices described design effort for the controlled recirculation is considerable, as in addition to the components for the drying of the biomass, the supply and discharge of process air and the device for pressing the dried biomass in fittings a refrigeration system with evaporator too install. In addition, there is the control and regulation technical effort in the coordination of the refrigeration process parameters with the process steps of drying and promotion of biomass. During the extensive testing has finally shown that the control and the equipment required for this equipment for an operator of such a system are economically unattractive.

On this basis, it is an object of the invention to provide a generic method and devices with which the energy and equipment required for the treatment of biomass is minimized.

According to the invention the object is achieved by the features mentioned in the independent claims.

With regard to the method for processing biomass is provided according to the features of claim 1, the biomass feed a fuel dryer in batches and thereby to dry by circulating with process air. After discharging the dried biomass from the fuel dryer this is in Pressed pieces. The process air flowing continuously through the fuel dryer can be heated upstream of the fuel dryer by means of a heating medium in a heat exchanger, and the process air moistened in the fuel dryer is then removed from the fuel dryer. The drying process finally comes to an end when either the biomass in the fuel dryer or the discharged process air has reached a target moisture.

The particular advantage of this invention lies in the fact that the process of preparing the biomass for use in a heating system with a few, simple components can be represented and thus the treatment process with few controlled variables is reliably controlled. Optionally, the target moisture content of the biomass in the fuel dryer or the discharged process air is available as a control variable, the detection of the target moisture of the biomass in the fuel dryer being a more direct and precise process control. Expediently, the process management, the detection and control of the relevant process parameters via a programmable controller, such as a commercially available Simatic control.

This can important u.a. Quality parameters of the fittings or pellets to be produced are respected or controlled via relevant standards. This particularly concerns the water content for pellets for non-industrial and industrial use. For wood pellets, for example, ISO 17225-2 "Biogenic Solid Fuels - Fuel Specifications and Classes" applies.

Due to the compact design of the device with its components, it is possible to design the device as a mobile plant parts that can be loaded or mounted on a vehicle for service purposes - such as contractors - are used.

In a further development of the invention, the fuel dryer is provided with an additional heater to accelerate the drying process. The heater is part of the surface formed on the lateral surface of the dryer drum and preferably extends over a circumferential angle α of about 75 ° to 225 °.

Further advantageous embodiments of the invention will become apparent from the dependent claims. The invention can be better understood by reference to the attached Figures 1 to 5 taken. Show it

1 shows a simple, schematic process flow diagram for a method according to the invention for the treatment of biomass,

 2 shows a schematic cross section through a device for processing biomass with representation of the mass flows,

 3 shows a side view of a device for processing biomass with designation of the components,

 3a shows a cross section A-A according to FIG. 3 of the device,

 Fig. 4 is a perspective view of a device and

 Fig. 5 is a schematic plan for illustrating the biomass flow.

In Fig. 1 is a schematic process flow diagram for a method for processing biomass B is shown.

For carrying out the method, a device 1 for processing biomass B is shown schematically. The device 1 consists essentially of a fuel dryer 2 with a drying drum 3, which is formed in the manner of a horizontal hollow cylinder with a horizontal axis of rotation 4. The fuel dryer 2 has an approximately centered on the shell periphery of the drying drum 3 provided, closable filling opening 5, through which the drying drum 3 with biomass B can be charged. The filling opening 5 is above the axis of rotation 4 and extends approximately parallel to this, so that when charging the fuel dryer 2, the biomass B falls under gravity approximately in the center of the dryer drum 3.

Diametrically the filling opening 5 opposite, lying on the lower shell portion is a closable outlet opening 6 is located, which extends approximately parallel to the axis of rotation 4. Dried biomass B is removed from the fuel dryer 2 via this outlet opening 6. From there, the dried biomass B can be fed to a storage bunker, not shown, for pelleting. At the front end of the drying drum 3, an air inlet opening 7 is provided, via which the drying drum 3 is supplied with process air L. Upstream of the air inlet opening 7, a heat exchanger 8 is arranged, via which the process air L by means of a heating means W is temperature controlled. The heat supply with respect to temperature and amount of heat can be controlled via a control device for process control of the device 1. As a means of heat W is not shown water cycle of an exhaust gas heat exchanger of a heating system. The heating system in turn is heated with the pellets produced by the device 1. As a rule, the temperature of the process air L when entering the fuel dryer 2 is 60 ° C.

At the opposite end face of the drying drum 3 is an exhaust duct

9 is provided, via which the humidified process air L is discharged from the drying drum 3. For this purpose, downstream of the air outlet opening 9 is a blower

10 arranged which promotes the process air L. The resulting during operation of the blower 10 in the drying drum 3 pressure drop suppresses the unwanted dust discharge from the fuel dryer. 2

The fuel dryer 2 is further detailed in Figures 3, and 3a.

1, the material flow of the biomass B during operation of the device 1 in three sequential successive base phases a) to c) can be represented: a) filling: the fuel dryer 2 is manually or mechanically with a batch biomass B. , which is undried, including the water contained, filled, the batch is previously measured in their amount. b) Drying: the fresh biomass contained in the fuel drier 2 is circulated with preheated process air L and dried to a predeterminable target moisture (14% or less), thereby increasing the humidity of the process air L during the drying process and downstream within the fuel drier 2.

c) emptying: the dried biomass B ("dry biomass") is discharged via the outlet opening 6 from the fuel dryer 2 and conveyed away for further utilization. Likewise, with reference to FIG. 1, the mass flow of the process air L and its process work during the operation of the device 1 in the following four base phases A) to D) are shown:

A) heating of the process air L coming from the ambient air via a heat exchanger 8 to about 70 ° C,

 B) Introduction of the heated process air L in the fuel dryer 2, wherein the introduction during the drying process takes place temporarily or permanently

C) absorption of the water vapor from the fresh biomass B, further heating of the fresh biomass B in the fuel dryer 2.

 D) The largely saturated process air L leaves fuel dryer 2 on the opposite side, wherein the process air L is conveyed by a blower 10.

The mass flow of the process air L, the material flow of the biomass B are controlled during operation of the device 1 via a control unit not shown, so that after filling the fuel dryer 2 with a batch of biomass B, the drying process runs automatically controlled.

Fig. 2 shows the device 1 with respect to the device 1 shown in Fig. 1 in a higher level of detail with other components. In addition to the components shown in FIG. 1, the following is shown in FIG.

Inside the dryer drum 3, a coaxially arranged rotor 11 is installed, which is provided with gripping arms 12 which are arranged distributed over its circumference and axially. The rotor 1 1 coupled to a rotary drive 13 circulates with the biomass B located in the drying drum 3 during operation and brings it into contact with the process air L flowing through the drying drum 3. The radially extending gripping arms 12 act mechanically on the biomass B. and crush them. During operation, the direction of rotation of the rotor 11, clockwise or anti-clockwise is reversible.

Above the filling opening 5, a filling funnel 22 is formed, via which the fuel dryer 2 is charged with bulk material B present biomass. The Filling opening 5 is closed by a slide 14, so that during the drying process and during operation of the rotor 11, the fuel dryer 2 remains closed. This is a safety aspect to avoid that people or objects may accidentally fall into the dryer drum 3. In addition, the slider 14 has a dust seal 24, whereby an unwanted dust contamination of the environment is avoided.

At the downstream, front end of the drying drum 3, the exhaust duct 9 is connected to this via which the heated and moist process air L is discharged from the drying drum 3 and discharged to the outside. About a arranged in the exhaust duct 9 via the control unit controllable fan 10, the mass flow of the process air L is controlled. About a downstream downstream separator, the recorded in the process air L particles, such as dust, etc. are separated and fed to the fuel dryer 2 for recovery. The thus purified process air L then passes into the open, with a residual dust amount of max. 20 mg / m ^{3 is} achieved.

Compared to the device 1 described with reference to FIGS. 1 and 2, the device 1 according to FIG. 3 is supplemented by further functional components.

After the biomass B has dried up to a target moisture of at most 14% that can be predetermined via the control unit and the comminution of the long-fiber fractions in the drying drum 3, pelleting takes place in a further method step. Through this process step, the biomass B for a continuous feed of a heating system is easier to handle. In addition, pelleted biomass B can be stored very well without significantly changing its physicochemical properties. The pellets can be stored in short-term or long-term storage facilities such as silos 16. In addition, they are easy to transport as pellets because of their ease of handling with an automatic conveyor. Thus, a screw conveyor or a chain conveyor or a conveyor belt may be provided to remove the pellets from the silo again and supply a burner to a heater.

The waste heat generated in a heating device can be used, for example, in two ways. On the one hand, a hot water cycle for a residential or farm building or the like can be operated in the vicinity of stables. On the other hand, hot water can be made available for the buildings. A heat exchanger 8 with the heating device can also be operated in such a way that with the aid of the heat exchanger 8 the process air L for dehumidifying and drying the biomass B is heated and a high saturation deficit is thus achieved.

For pelletizing the biomass B, as shown in FIG. 3, a commercial pelletizer 17 is added to the device 1. The dried biomass B taken from the fuel dryer 2 via the outlet opening 6 is conveyed away via a conveyor screw 18 to a buffer 19. From there, the biomass B for pressing the fittings passes into the pelletizer 17. The finished pressed, pellets then pass through a further conveyor 20 into the silo 16th

FIG. 3 a shows a cross-section A-A according to FIG. 3 of the device 1.

In the center of the cross section A-A, the drying drum 3 of the fuel dryer 2 can be seen. Whose longitudinal axis also forms the axis of rotation 4 of coaxially mounted inside the dryer drum 3 rotor 11. The rotation axis 4 extends perpendicular to the plane of the cross section A-A. As the direction of rotation arrow shows, the rotor 11 is left-handed during operation.

Further, the cross-section AA within the dryer drum 3 is divided into four quadrants I, II, II I and IV for ease of further reference with center Z lying on the rotation axis 4, with quadrant I upper right, quadrant II lower right, quadrant III bottom left and quadrant IV at the top left.

In the area of the quadrant IV, the filling opening 5 is formed on the shell periphery of the drying drum 3 via which the drying drum 3 is charged with biomass B. In the area of the quadrant III, the outlet opening 6, which can be closed by means of a flap 23, is carried out on the outer circumference of the drying drum 3, via which dried biomass B is conveyed out of the drying drum 3. Both the filling opening 5 and the outlet opening 6 have, as can be seen in FIG. 3, apart from the expansion in the circumferential direction, an extension in the axial direction of the drying drum 3. The relative to the center Z laterally offset formation of the outlet opening 6 is beneficial when emptying the drying drum 3. By the example in the example left-turning rotor 11, the biomass B along the inner wall of the dryer drum 3 over the areas of the quadrant in the order of the circumferential direction III-II-L moves, thrown and finally falls left of the rotor 11, in the region of the quadrant III on the Bottom of the drying drum 3 down where the initially closed outlet opening 6 is located. The laterally offset formation of the outlet opening 6 thus considerably facilitates the residue-free emptying of the drying drum 3 and also reduces the overall height of the fuel dryer 2. A one or more reversal of the direction of rotation of the rotor 1 1 enables substantially complete emptying via the opened outlet opening 6.

To accelerate the drying process, the fuel dryer 2 is provided with an additional heater 26, whereby the biomass B is heated directly and therefore more efficiently. The heater 26 partially contacted the inner wall of the drying drum 3 in the region of the quadrants I, II and III over a circumferential angle α of about 150 °. The heater 26 is formed by non-illustrated meandering tubes, which is connected to a hot water heater. In the longitudinal direction, the heater 26 extends just above the effective inner length of the dryer drum. 3

The heater 26 thus predominantly heats the lower right inner side of the drying drum 3 so that in the case of left-handed operation of the rotor 1 1, the biomass B is moved by the gripper arms 12 over the regions of the quadrants in the order of the circumferential direction III-II-L. The biomass B sweeps over the heated inside and is thus heated. In the area of the quadrants I and IV, the biomass B falls from the inner surface in the area of the quadrants II and III, from where the biomass B is reheated along the heated inner wall until the drying process is completed. A heating in the area of the quadrant IV is not required and thus unnecessary, especially since there is virtually no contact of the biomass B with inner wall.

Due to the design of the heater 26 in the area of the coated by the biomass B inner wall of the dryer drum 3 present as bulk biomass B is moved by the rotor 11 along the heated inner wall. essential borrowed here is that the heater 26 is formed in the region of the rising in operation of the rotor 11 gripping arms 12, since there the biomass B is supported by the gripping arms 12 on the inner wall upwards. The heat transfer from the heated inner wall to the biomass B is thus immediate and optimal.

On the rotor 1 1 six radially extending gripping arms 12 are mounted at the same angular distance, which extend radially to the inner wall of the drying drum 3 and form with this a small gap of a few mm. The gap is large enough to compensate for different, operational expansion between the gripping arms 12 and the dryer drum 3, without the gripping arms 12 start in operation on the inner wall. At the same time, the gap is small enough that the biomass B can be completely gripped and circulated without biomass being able to deposit on the inner wall of the drying drum 3. At the drum-side end of the gripping arms 12 plate-shaped grippers 21 are mounted, which promote the biomass B from the bottom of the dryer drum 3, raise and bring in the flow of process air L. The biomass B is comminuted and dried by circulating the process air L.

In Fig. 4 shows the device 1 in a perspective view. The fuel dryer 2 is provided on the outer circumference of the drying drum 3 with a heat insulation 26 in order to avoid heat losses during operation of the fuel dryer 2 and to optimize the efficiency of the device. In addition, the extent of attached to a part of the outer surface of the drying drum 3 heater 26 can be seen in the longitudinal and circumferential directions.

The schematic process diagram according to FIG. 3 illustrates the separation of the biomass B before it enters the fuel dryer 2. Using the example of a biomass B originating from stables, there are generally three forms of operation for processing the biomass B: a) Separation of the raw, untreated biomass B into its constituents manure and bedding, feeding the manure to the fuel dryer 2, further processing of the manure as fertilizer,

b) Separation of the raw, untreated biomass B in its components dung and litter, feeding the litter to the fuel dryer 2, further processing of the litter as fuel or c) feeding the untreated biomass B to the fuel dryer 2, further processing the biomass B as fuel.

Hereinafter, production characteristics from the trial operation of the device 1 will be explained. In a first drying cycle, a batch with 165 kg of biomass B with a water content of originally 42% was reduced to 13%. The batch was deprived of 55kg of water during a runtime of 8h13min. The resulting energy balance is shown in the table below:

In a second drying cycle, a batch with 228 kg biomass B with a water content of originally 54% was reduced to 18%. The batch was deprived of 100 kg of water for a period of 11 h 25 min. The resulting energy balance is shown in the table below:

Energy balance (228 kg with 54% to 18

 %)

 Oil price 0.6 €

used amount of heat 9.74 kWh Calorific value of 1 liter oil 10.00 kWh theoretical oil consumption 1, 00 I theoretical costs for oil 0.60 € corresponds to wood briquette at F. 2.5 2.50 kg

Electricity consumption 17.00 kWh

Electricity costs € 0.20 / kWh € 3.40

Total cost of energy 4.00 €

Total weight after drying 127.80 kg

Surplus 30,07 €

Excess in oil converted 50, 12 I theoretical net income 10975.55 €

LIST OF REFERENCE NUMBERS

Facility

 fuel dryer

 dryer drum

 axis of rotation

 fill opening

 outlet opening

 Air inlet opening

 heat exchangers

 exhaust duct

 0 blower

 1 rotor

 2 gripping arms

 3 rotary drive

 14 slides

 15 separators

 16 silo

 17 pelletizers

 18 screw conveyor

 19 cache

 0 subsidies

 21 grippers

 22 filling funnel

 23 flap

 24 dust seal

 25 rotary drive

 26 heating

 27 heat insulation

 B biomass

 L process air

 W heating means

 Z center

Claims

claims 1. A method for processing biomass (B) for use in a heating system in which the biomass (B) fed to a fuel dryer (2) in batches and dried by circulating continuously supplied process air (L) and after drying from the fuel dryer ( 2) is discharged, characterized in that  The process air (L) flowing through the fuel dryer (2) can be heated upstream of the fuel dryer (2) by means of a heating medium in a heat exchanger (8),  • the process air (L) moistened in the fuel dryer (2) is removed from the fuel dryer (2) and  • the circulation with process air (L) ends after reaching a target moisture level of the biomass (B) or the discharged process air (L) in the fuel dryer. 2. The method according to claim 1, characterized in that for heating the process air (L) of the heat exchanger (8) is connected to a hot water circuit. 3. The method according to claim 2, characterized in that the hot water circuit is heated by means of exhaust gas heat exchanger of a heating system. 4. The method according to any one of the preceding claims, characterized in that the process air (L) during the drying of the biomass (B) is continuously fed to the fuel dryer (2). 5. The method according to any one of the preceding claims, characterized in that the fuel dryer (2) flowing through process air (L) by means of a downstream of the fuel dryer (2) arranged fan (10) is promoted. 6. The method according to any one of the preceding claims, characterized in that the process air (L) downstream of the fuel dryer (2) flows through a separator (15) for separating the particles. 7. The method according to claim 6, characterized in that the process air (L) downstream of the fuel dryer (2) flows through a filter for separating the particles from the process air (L), wherein the filter preferably combined with the separator (15) or structurally integrated is. 8. The method according to claim 6 or 7, characterized in that the particles fed to the fuel dryer (2) or mixed with the biomass (B) and pressed into fittings. 9. The method according to any one of the preceding claims, characterized in that in the fuel dryer (2) located biomass (B) is heated by means of a heater. 10. The method according to any one of the preceding claims, characterized in that the removal of the dried biomass (B) after reaching a predetermined target moisture in the fuel dryer (2) located biomass (B), wherein the target moisture is preferably 14% or less. 1 1. A method according to any one of the preceding claims, characterized in that after the removal of the biomass (B) from the fuel dryer (2) this is pressed into fittings, in particular in pellets. 12. The method according to any one of the preceding claims, characterized in that the biomass contains at least litter and manure and before being fed into the fuel dryer (2) are separated into the constituents bedding and manure so that the fuel dryer (2) as biomass (B) only the ingredients bedding or manure are supplied. 13. A device (13) for processing biomass (B) according to the method of one of the preceding claims, characterized in that the fuel dryer (2) a drying drum (3), a filling opening (5) for filling and an outlet opening (6) for the removal of biomass (B), whereby in the internal a device for moving the biomass (B) is arranged ren of the drying drum (3), wherein at the same time a drying and crushing of the biomass (B) takes place during operation. 14. Device according to claim 13, characterized in that the fuel dryer (2) is provided with a heater for heating the biomass (B). 15. Device (13) for conditioning and drying of biomass (B), in particular according to the method of one of claims 1 to 12, with a fuel dryer (2), which has a drying drum (3), wherein The drying drum (3) has a filling opening (5) for filling and an outlet opening (6) for removal of biomass (B),  A device for moving the biomass (B) is arranged inside the drying drum (3) along the inner wall of the drying drum (3), • for drying the biomass (B) the drying drum (3) tempered process air (L) is supplied,  • the drying drum (3) is provided with a heater (26) for heating the biomass (B), and  • during operation at the same time a drying and crushing of the biomass (B) takes place. 16. Device according to one of claims 13 to 15, characterized in that the device for moving and crushing the biomass (B) has a rotor (23) with grippers (24) and a rotary drive (25) for rotating the rotor (23) , 17. Device according to one of claims 13 to 16, characterized in that the device for moving and crushing the biomass (B) has a rotor (23) which is arranged coaxially within the drying drum (3). 18. Device according to one of claims 13 to 17, characterized in that the heating of the fuel dryer (2) via a heating means or is electrically operated. 19. A device according to any one of claims 13 to 18, characterized in that the heating part of the surface on the jacket of the drying drum 3 along a Umfangsab- section is executed. 20. Device according to one of claims 13 to 19, characterized in that a cross section of the cylindrical drying drum 3 in the circumferential direction (L / R) quadrants I, II, III and IV describes and wherein the heater (26) at least part of the surface on the jacket of the drying drum 3 is formed at least in the area of the quadrants I and II or IV and III.