EP2897792A1

EP2897792A1 - Method for separating litter from liquid manure

Info

Publication number: EP2897792A1
Application number: EP13756819.2A
Authority: EP
Inventors: Otto Roiss
Original assignee: Roehren und Pumpenwerk Bauer GmbH
Current assignee: Roehren und Pumpenwerk Bauer GmbH
Priority date: 2012-09-20
Filing date: 2013-08-23
Publication date: 2015-07-29
Also published as: CA2884697A1; US20140076801A1; CN104781066A; RU2015111007A; WO2014044350A1; DE102012018650A1

Abstract

The invention relates to a method for separating litter from liquid manure (1), comprising the following steps: feeding liquid manure (1) into a separator (2) which separates the solid constituents (11) and the liquid constituents (12) of the liquid manure; squeezing a first quantity of a solid (6) per time unit from the liquid manure by means of the separator (2) and squeezing a second quantity of the solid (6) per time unit from the liquid manure (1) by means of the separator (2), wherein the solid (6) has a first dry substance content; feeding the solid (6) to a litter recovery unit (3); heating the solid (6) inside the litter recovery unit (3) from an infeed temperature (4) to a target temperature (5); and holding the solid (6) at a temperature above the target temperature (5) and for a first time period, wherein the first quantity is smaller than the second quantity if the infeed temperature (4) increases within a measurement interval (40), and wherein the first quantity is greater than the second quantity if the infeed temperature (4) drops within the measurement interval (40).

Description

Process for separating litter from manure

description

The invention relates to a method for the production of litter from liquid manure, in particular manure solids to be used as litter. Such a method is advantageously used in dairies, in order to buy at best no bedding material. Litter is used in the stalls of dairy cattle farms to cover the soil and is a prerequisite for hygienic animal husbandry. Several methods are known from the prior art, in which manure solids are pressed out of the manure in order to subsequently use these as litter. However, when using manure solids as litter, EC Regulation 1774/2002, "Hygiene requirements for animals not intended for human consumption, is It states, inter alia, that such products must undergo a temperature treatment of at least one hour above 70 ° C. Therefore, this requirement introduces new conditions to the method of separating litter from manure, which is not known from the known methods Thus, the prior art can not reliably ensure the required heat treatment.

It is therefore an object of the invention to provide a method that allows a simple and cost-effective application of a proper separation of bedding from manure. It is a particular object of the invention that a time-defined heat treatment of the bedding material is ensured in the process.

The object is achieved by the features of claim 1. This discloses a method for separating litter from manure, wherein the following steps are performed: First, the slurry to be used is fed to a separator which separates solid components and liquid components of the slurry. In the separator, a first amount of a solid per unit time is squeezed out of the manure. Likewise, a second amount of the solid per unit time of the slurry is squeezed through the separator. It is preferably provided that first the first amount per unit time of the manure is squeezed and then the second amount per unit time. According to the invention, the first quantity per unit of time is pressed out over the duration of a predefined measurement interval. It is then determined how large the second amount per unit time must be. The determination of the second quantity per time unit follows a control process which is dependent on the further method steps. The thus expressed solid has a first dry matter content, regardless of whether the separator presses out the first amount per unit time or the second amount per unit time.

Finally, the recovered solid is fed to a litter recovery plant where the solid is heated from an inlet temperature to a target temperature while the solid is being transported from an input of the litter recovery plant to an exit of the litter recovery plant. It is therefore preferable to reach the target temperature before the exit of the litter recovery plant (t), so that the solid material is still in To be traveled path to the output of the litter recovery system follows a temperature profile (is maintained at a temperature), which is above the target temperature. It is thus possible to determine a first period of time in which the solid is exposed to a temperature which is above the target temperature. In order to keep the first period of time above a predetermined value, according to the invention, the amount of solid which is pressed out by the separator per unit of time and which is thus supplied per unit time to the litter recovery system, depending on the input temperature of the solid upon entry into the litter Regulated recovery system. Thus, the previously described determination of the second amount per unit time is dependent on the input temperature of the solid. If the inlet temperature rises within the measurement interval, the first amount is less than the second amount. If, however, the inlet temperature falls within the measuring interval, the first quantity is greater than the second quantity. With this feedback, therefore, the input temperature, which has the solid when filling in the litter recovery system, can be kept constant or at least within specified limits.

The dependent claims have preferred developments of the invention to the content. The process according to the invention is preferably carried out by the separator squeezing out the solid by means of a screw drive. For this purpose, a screw core of approximately 180 mm is preferably used with a screw diameter of 260 mm. The use of the worm drive according to the invention allows a regulation of the torque, so that the dry matter content of the pressed solid can be adjusted via the torque of the worm drive. Thus, it is advantageously possible with the worm drive to always squeeze solid with the first dry matter content.

Particularly preferably, it is provided that the first amount per unit time and the second amount per unit time on the speed of the worm drive is adjustable. The output of the separator can thus be set very easily. In connection with the regulation of the torque, therefore, a decoupled system is available, as with the regulation of the torque preferably the dry matter content is regulated, while on the speed preferably the discharge rate per unit time is regulated.

In an advantageous embodiment, the litter recovery system to a drum, wherein the drum rotates at a first rotational speed and the solid is preferably transported parallel to the axis of rotation. The rotation has the advantage that the filled solid is mixed in the bedding recovery plant, so that a homogeneous mixture is formed. It is likewise advantageous if the drum has an insulation and / or is located in an insulated space. In this way, heat losses can preferably be reduced.

Particularly preferably, the rotational speed of the drum is 0.5 to 1.5 revolutions per minute. Such a rotational speed allows a good mixing of the solid in the drum.

Likewise, it is particularly preferred that the degree of filling of the drum is adjustable 45% to 70%. In particular, it is particularly preferred that the degree of filling of the drum is 65%. With such a degree of filling, the relative heat losses of the solid in the drum are particularly low.

Furthermore, it is advantageous if the litter recovery system is ventilated via a ventilation system. The air thus supplied may preferably be heated to heat the solid within the bedding recovery plant. Preferably, the air is supplied in countercurrent process, so that the air is supplied to the litter recovery plant at the point where the solid leaves the litter recovery system, while the air is discharged at the point at which filled the solid in the Einstreurückgewinnungsanlage becomes. Alternatively or additionally, it is advantageous to adjustably heat the solid before it is fed to the straw recuperation plant. For example, after being pressed out of the separator, the solid can be conveyed through another element which heats the solid before the solid is introduced into the litter recovery unit. The method according to the invention is advantageously carried out in such a way that the first period of time is at least one hour and / or the measuring interval is preferably half an hour. By choosing the first time span of at least one hour, the requirement of the aforementioned EC Regulation 1774/2002 is met. The choice of the measuring interval of half an hour is advantageous in terms of the stability of the control loop, consisting of litter recovery plant and separator. The selected periods therefore make it possible to carry out the method according to the invention safely and reliably. The process according to the invention is likewise preferably carried out in that the first dry matter content is between 35% and 42%, particularly preferably between 37% and 38%. On the one hand, these values are easily accessible through the separator, on the other hand, it has been shown that the litter should have a dry matter content of about 40%. Since further drying takes place during the passage of the solid through the bedding recovery plant, it is advantageous to select the first dry matter content with which the separator presses the solid out of the liquid manure between 37% and 38%.

Preferably, an inlet temperature of 50 ° C to 60 ° C is selected, with an inlet temperature of 55 ° C should prevail particularly preferred. These values allow an optimum temperature profile of the solid over the length of the bedding recovery plant. Furthermore, it is preferably provided that the target temperature is above 70 ° C. This ensures that the method according to the invention in this advantageous embodiment meets the requirements of the aforementioned EC Regulation 1774/2002.

Since even a brief drop below a predefined input temperature can no longer be guaranteed that the solid is held above 70 ° C for at least one hour, as prescribed by the EC Regulation 1774/2002, is advantageously provided that falls below a warning temperature Alarm signal is output. In this case, an operator can recognize the situation and, if necessary, initiate further countermeasures manually. Finally, it is preferably provided that a biocenosis is produced in the litter recovery plant, which preferably contains thermophilic bacteria. The biocenosis is preferably influenced by the monitoring of the temperature development of the inlet temperature and the control of the supply of the solid.

In an advantageous embodiment, the feeding of the liquid manure to the separator takes place from a central warehouse, wherein the liquid manure in the central warehouse can be advantageously homogenized by means of an agitator. Preferably, it is also contemplated that the temperature rise of the solid within the bedding recovery plant is constant over the length of the bedding recovery plant so that the solid is transported from the bedding recovery plant entrance to the bedding recovery plant exit, with a linear flow Temperature profile is heated.

Furthermore, the method according to the invention is preferably used continuously. This means that first the first amount of solid per unit time is pressed out over the duration of the measurement interval, then the second amount per unit time is determined, so that the second amount of solid per unit time over the duration of the measurement interval is pressed and then the inventive method starts again. Thus, the now expressed second amount of the solid per unit time is again regarded as the first amount of the solid per unit time and again determined after the measurement interval, a second amount per unit time. In this way, the inlet temperature can advantageously be regulated continuously within predetermined limits.

The invention will now be described in more detail by means of embodiments with reference to the accompanying drawings. 1 shows a schematic overview of a system with which the method according to the invention can be carried out according to a preferred exemplary embodiment, 2 shows a schematic structure of a separator, with which the method according to the invention according to the preferred embodiment can be advantageously carried out, FIG. 3 is a schematic overview of the logical structure of the system of FIG.

1, a schematic overview of the litter recovery system and the temperature profile of a solid therein when the method according to the invention is used according to the preferred embodiment, and an exemplary course of the inlet temperature when using the method according to the preferred embodiment.

Fig. 1 shows a system with which preferably the method according to the invention can be carried out. In this case, manure 1 is collected in a collecting container 100 and advantageously homogenized by a stirrer 102. Via a pump 101, the manure 1 is finally fed to the separator 2, which is set up to separate solid constituents 11 from liquid constituents 12 of the manure 1. The liquid components 12 of the slurry are not needed here and therefore transported away. The solid constituents include, for example, the solid material 6, which is fed via a screw conveyor 9 to the straw recuperation plant 3.

The separator 2 is shown in detail in FIG. Thus, the liquid manure 1 is introduced into the separator 2 and compressed via a worm drive 7, so that solid constituents 11 and liquid constituents 12 are discharged from the separator 2. The worm drive 7 is driven by a motor 20, wherein torque and speed of the motor 20 are controlled separately. First, the speed of the motor 20 is controlled by a speed controller 22. The speed controller 22 therefore receives a signal feedback, which is discussed in more detail in Fig. 3. Furthermore, the separator 2 has a torque controller 21, which exerts a counter pressure on the solid 6 emerging from the separator 2. The motor 20 must therefore have a corresponding rotary torque to overcome the back pressure of the torque controller 21. With the choice of the back pressure, the torque controller 21 can therefore control the torque of the motor 20. In interaction, speed controller 22 and torque controller 21 can thus accurately determine the dry matter content of the emerging solid 6. On the other hand, by changing the rotational speed of the engine 20, the separator 2 can increase or decrease the discharge rate of the solid 6. Thus, the separator 2 can firstly respond to requirements of the amount of discharged solid 6 by the litter recovery system 3, on the other hand, the separator 2 can ensure that the ejected solid 6 always has a first Trockensub- content. This is advantageous insofar as the manure 1 due to various external influences, such as different feed compositions in different seasons, cleaning methods with more or less water to fluctuating needs, wet, cold, warm or dry weather phases or decomposition processes by different storage times in their composition usually varies greatly. Thus, it can be achieved by the separator 2 that the solid 6, which is supplied to the litter recovery system, always has a constant dry matter content.

In Fig. 1, the litter recovery system 3 is further shown. This is designed as a drum and is about 10 meters long. In addition, the drum is rotated at a speed of 0.5 to 1.5 revolutions per minute, with the drum being rotated, for example, at a speed of 1 revolute per minute. At a first end face 30 of the litter recovery system 3, the solid 6 is supplied. The solid 6 then passes through the litter recovery system 3, to finally be discharged at the second end face 32 again. Furthermore, a ventilation device 8 is present, the air on the second end face 32 of the litter recovery system 3 on and on the first end side 30 derives. In this case, the air supplied through the ventilation device 8 can be heated, so that the temperature within the litter recovery system 3 can be influenced. It is also possible to heat the solid 6 via the screw conveyor 9 in order to adjust the inlet temperature of the solid 6 at the first end face 30 of the litter recovery system. Finally, the litter recovery plant 3 has insulation and is mounted inside an insulating container 300. Fig. 3 shows schematically the logical structure of the plant described above, as outlined in FIGS. 1 and 2. In the sketch of FIG. 3, arrows that strike a module perpendicularly display information flows, while arrows that meet components horizontally indicate mass flows.

According to the invention, manure 1 is first supplied to a separator 2. The separator 2 is set up to separate the manure 1 into solid constituents 11 and liquid constituents 12. In the separator 2, a solid 6 is squeezed out, wherein an amount of the discharged solid per unit time and the dry matter content of the solid can be regulated via the speed governor 22 and via the torque controller 21. First, a first amount of the solid 6 per unit time is delivered to the screw conveyor 9. The screw conveyor 9 conveys the first amount of the solid 6 per unit time to the litter recovery system, which is thus filled by the screw conveyor 9 with the solid 6. A temperature sensor 31 is disposed on the litter recovery system 3 and determines an input temperature 4 of the supplied solid 6. As soon as a measurement interval, for example 30 minutes, has passed, the temperature sensor 31 detects the input temperature 4 and returns it to the speed controller 22. By this signal feedback thus creates a control loop, since the speed controller 22 controls the speed of the motor 20 of the separator 2 due to the input temperature 4. If the inlet temperature 4 has risen within the measuring interval, the separator 2 is adjusted by the speed controller 22 in such a way that from now on a second quantity of the solid 6 per unit time is squeezed out, the second quantity being greater than the first quantity. If, on the other hand, the inlet temperature 4 has fallen within the measuring interval, the second quantity is less than the first quantity. In this way, the input temperature 4 of the solid 6 at the litter recovery unit 3 can either be lowered by supplying a larger amount of solid, or increased by supplying a smaller amount. This results in a continuous process, in which the input temperature 4 serves as a controlled variable and the speed of the motor 20 as a manipulated variable.

In addition to the above-mentioned regulation, it is furthermore possible to supply heated air via the aeration system 8 to the litter recovery system 3 in order to: to further increase the temperature of the solid 6 within the bedding recovery plant. Alternatively or additionally, the screw conveyor 9 may also heat the solid 6 prior to feeding to the bedding recovery plant 3. Fig. 4 shows schematically the structure of the litter recovery system 3. In this case, the solid 6 is filled at a first end face 30, wherein also on the first end face 30 of the temperature sensor 31 determines the inlet temperature 4 of the solid 6. Also shown in Fig. 4 is a diagram showing the vertical axis of the temperature profile over the length of the litter recovery system (longitudinal axis). It can be seen that the temperature profile is linear. Starting from an inlet temperature 4, the temperature of the solid 6 rises, the temperature within a first area 33 of the litter recovery plant being below a target temperature 5. In a second region 34 of the litter recovery system, however, the temperature of the solid 6 is above the target temperature. 5

For example, the solid 6 is transported through the bedding recovery plant 3 at a rate of 1 meter per hour. Thus, it follows that the first region 33 may be at most 9 meters long so that the second region 34 has a length of at least 1 meter. In this case, it is ensured that the solid 6 is kept within the second area 34 for at least 1 hour in order to be exposed to a heat treatment of at least 1 hour above the target temperature 5. The target temperature 5 is, for example, 70 ° C. In this case, according to the invention, the inlet temperature 4 in about 50 ° C. This results in a favorable temperature profile over the length of the litter recovery system. 3

Fig. 5 shows schematically a temperature profile of the inlet temperature 4 when the inventive method is applied. Here, the vertical axis illustrates the amount of temperature 4, while the horizontal axis represents the time axis. An upper limit temperature 41 and a lower limit temperature 42 indicate a working range in which the inlet temperature 4 must be maintained in order to be able to reliably and reliably carry out the required heat treatment of the solid 6. According to the invention, therefore, after a first measuring interval 40, for example after half an hour, it is determined that the inlet temperature 4 has dropped. Therefore, will used this temperature information to the speed of the motor 20 of the worm drive 7 by the speed controller 22, which is designed for example as a frequency converter to slow down by an adjustable amount. However, the solid 6 now remains longer in the worm drive 7 of the separator 2, which would lead to an increase in the dry matter content of the solid 6. However, the increase in the dry matter content of the solid 6 also means an increase in the torque acting on the worm drive 7. Thus, the torque controller 21 can counteract this and reduce the torque acting on the worm drive 7, lower. In this way, the dry matter content of the solid 6 is kept constant. Overall, less solid is released to the litter recovery system 3, whereby in a next measurement interval 40, the input temperature 4 increases.

Should the inlet temperature 4 fall below the lower limit 42 or exceed the upper limit 41, then the optimum working range is left and there is a risk that the required temperature treatment of the solid 40 no longer takes place as required. In this case, for example, an alarm can be triggered to alert an operator of the system to this circumstance. Especially in winter months, the inventive method is particularly advantageous because it can come here at sudden cold spells disturbances in the operation of a conventional plant for the production of bedding from manure. In order to counteract such situations, the heated air may preferably be supplied to the bedding recovery plant 3 through the aeration device 8, or the solid 6 may be heated by the screw conveyor 9 before being fed to the bedding recovery plant 3. Overall, it is thus ensured that a biocenosis is produced by the inventive method in the litter recovery system 3, at the end of a heat treatment of the supplied solid 6, in which the solid 6 is maintained above a temperature of 70 ° C, where the heat treatment lasts at least 1 hour.

Claims

claims

A process for separating litter from manure (1) comprising the steps of:

Feeding manure (1) to a separator (2) which separates solid components (1 1) and liquid components (12) of the manure,

- Squeezing a first amount of a solid (6) per unit time from the slurry through the separator (2) and pressing a second amount of the solid (6) per unit time from the slurry (1) through the separator (2), wherein the solid ( 6) has a first dry matter content,

Feeding the solid (6) to a litter recovery plant (3),

- Heating the solid (6) within the litter recovery system (3) from an inlet temperature (4) to a target temperature (5), and

- Holding the solid (6) above the target temperature (5) and over a first period, wherein

- The first amount is less than the second amount when the input temperature (4) within a measuring interval (40) increases, and

- The first amount is greater than the second amount, when the input temperature (4) within the measuring interval (40) decreases.

2. The method of claim 1, wherein the separator (2) the solid (6) by means of a worm drive (7) and presses a torque of the worm drive (7) is controlled to adjust the first dry matter content.

3. The method of claim 2, wherein the speed of the worm drive (7) is changed to the pressing of the first amount or the pressing of the second

Adjust the quantity through the separator (2).

4. The method according to any one of the preceding claims, wherein the litter recovery system (3) comprises a drum which is rotated at a first rotational speed.

5. The method of claim 4, wherein the first rotational speed is 0.5 to 1.5 revolutions per minute.

6. The method of claim 4 or 5, wherein the degree of filling of the drum is adjustable 45% to 70%, in particular 65%.

7. The method according to any one of the preceding claims, wherein the litter recovery system (3) via a ventilation system (8) preferably heated air is supplied and the amount of air supplied is adjustable, and / or optionally the solid (6) before Feeding to the litter recovery system (3) is heated adjustable.

8. The method according to any one of the preceding claims, wherein the first time period is at least one hour and / or the measuring interval is preferably half an hour.

9. The method according to any one of the preceding claims, wherein the first dry matter content is between 35% and 42%, preferably between 37% and 38%.

10. The method according to any one of the preceding claims, wherein the inlet temperature is 50 ° C to 60 ° C, preferably 55 ° C and / or the target temperature is above 70 ° C.

11.Verfahren according to any one of the preceding claims, wherein when falling below a warning temperature, an alarm signal is output.

12. The method according to any one of the preceding claims, wherein by monitoring the temperature development of the inlet temperature and the control of the supply of the solid in the litter recovery system (3) a biocenosis is generated, which preferably contains thermophilic bacteria.