JP7547568B2 - Litter recycling device and litter recycling method - Google Patents

Description

The present invention relates to a bedding recycling device used for livestock bedding.

Bedding is a flooring material laid on the floor of a livestock barn for livestock to lie or sit on. This bedding is required to have high cushioning and heat retention properties, to be non-slip, to be dry and hygienic to dry the skin surface of livestock and suppress bacterial growth, and not to injure livestock. In addition to liveability for livestock, it is also required to have high water absorption properties to absorb excrement and improve the ease of handling the excrement, and to adsorb the foul odor of excrement to reduce the foul odor of excrement.
Examples of bedding that are used include hay, straw, sawdust, rice husks, etc.

This type of bedding reaches the end of its usefulness when it absorbs the moisture from the excrement and becomes saturated with water. For example, in dairy cow breeding facilities, it becomes saturated with water within a few days. This means that every time the bedding becomes saturated with water, it must be replaced with new bedding. However, because hay and straw are not used as livestock feed, there are limits to the stable supply of these materials for the number of livestock being raised. Meanwhile, the prices of sawdust, rice husks, etc. are soaring amid growing demand for biomass power generation.

As such, bedding costs have become a major factor putting pressure on ranch management, and technology for recycled bedding, such as that described in Patent Document 1, has been developed.
Patent Document 1 discloses a method for regenerating livestock bedding, which makes used livestock bedding reusable, by a first step of drying the livestock bedding in the sun for several hours, a second step of fermenting the livestock bedding at high temperature, and a third step of forcibly air-drying the livestock bedding while forcibly stirring it for several days.

Japanese Patent Application Publication No. 9-172895

However, the technology of Patent Document 1 involves forcibly blowing air on the fermented livestock litter to dry out the moisture, and the drying process takes time, lasting 2 to 3 days. Furthermore, this drying process cannot remove substances (such as ammonia) that remain in the litter and that cause odorous gases, such as ammonia and hydrogen sulfide.
The present invention aims to provide a simple litter regeneration device that is low-cost and highly safe for livestock.

The bedding recycling device of the present invention is characterized by comprising a hot air generating section that generates hot air, and a drying section that agitates used bedding while drying it with the hot air to produce recycled bedding.
The bedding recycling device of the present invention dries used litter with hot air while stirring it, making it possible to sterilize the used litter and remove ammonia and other substances contained in the used litter.

In the bedding recycling device of the present invention, the used bedding is preferably dried feces-containing bedding obtained by drying feces-containing bedding or composted bedding obtained by fermenting and drying feces-containing bedding. In particular, the moisture content of the used bedding is preferably 20% to 85%.
Used litter made by drying manure-containing litter is easy to handle and suitable for drying with hot air.

In the bedding regeneration device of the present invention, the hot air is preferably at least 450° C. This makes it possible to further remove ammonia and the like.
In the bedding recycling apparatus of the present invention, it is preferable that the exhaust temperature of the drying section is 90° C. or higher. In this case, bacteria contained in the used bedding can be killed.

In the bedding recycling apparatus of the present invention, it is preferable that the drying section has a cylindrical treatment tank which is installed at an angle so that the end of the treatment tank from which the recycled litter is removed is lower than the end of the treatment tank from which the used litter is fed. By installing the treatment tank at an angle, the used litter moves from the input port of the treatment tank to the output port while being dried over a predetermined time.
It is preferable that the treatment tank has an outlet for removing the recycled litter. By directly removing the recycled litter from the treatment tank, it is possible to selectively remove only the recycled litter that is in a good condition suitable for reuse.
It is preferable that the treatment tank has a plurality of stirring blades attached to a shaft within the treatment tank, in which case the used bedding put into the treatment tank moves towards the outlet while being stirred and crushed.

The bedding recycling device of the present invention preferably has a dust collector that extracts powder from the exhaust air of the drying section, and extracts the powder collected by the dust collector as recycled bedding. In this case, recycled bedding can be produced more efficiently.

In the bedding recycling device of the present invention, the hot air generating section has a primary hot air generating section which generates primary hot air, and a secondary hot air generating section which generates secondary hot air which is at a lower temperature than the primary hot air by non-contact heat exchange with the primary hot air, and it is preferable that the drying section dries the used bedding with the secondary hot air.
Since the used bedding is dried using secondary hot air that is heat exchanged without contact with the primary hot air generated in the primary hot air generating section, the garbage contained in the primary hot air is not included in the recycled bedding. Furthermore, exhaust gases such as chlorine contained in the primary hot air do not affect the used bedding in the drying section. Therefore, cheap fuel can be used, and the recycling cost can be reduced. In particular, it is preferable that the primary hot air generating section generates the primary hot air by burning RPF fuel.

The bedding recycling device of the present invention dries used bedding with hot air while stirring it, producing recycled bedding that is safe for livestock.

FIG. 1 is a schematic diagram showing one embodiment of a bedding regeneration device of the present invention. 2a and 2b are a plan view and a side view, respectively, of the drying drum of the drying section of FIG. FIG. 3a is a side cross-sectional view showing the drum body of the drying drum of FIG. 2a, and FIGS. 3b and 3c are schematic views showing the attitudes of the stirring blades, respectively.

First, we will explain the target bedding.
Litter is a floor material for livestock such as cows, pigs, chickens, etc. to lie or sit on, particularly for cattle sheds.
Litter materials include agricultural products, wood, organic waste, and inorganic materials.
Agricultural products include rice straw, wheat straw (straw), rice husks, and hay.
Wood-based waste includes sawdust, sawdust, bark, chipper dust, pin chips, cutter chips (brainer, moulder, drill), curl mat, etc. Sawdust, pin chips and curl mat are either factory residues or are produced for bedding.
Organic waste includes waste paper, waste mushroom beds such as mushroom culture medium, demolition materials, tea leaves, biogas residue, etc. Demolition materials are the same as pin chips, but they contain unknown species, including tree species.
Inorganic materials include sand, crushed shells, and the like.
Litter is produced by mixing these materials alone or in combination. In particular, litter made mainly of wood-based materials is preferred because it can be supplied in large quantities, is suitable for mechanical work, and has high water absorption and water retention. Litter made mainly of crushed materials is also preferred.

Used bedding refers to bedding derived from bedding containing livestock manure. Examples include manure-containing bedding removed from cowsheds, dried manure-containing bedding in which the moisture in manure-containing bedding has been evaporated by ventilation or sunlight, and composted bedding in which the manure-containing bedding has been fermented and dried, that is, the organic matter in the manure-containing bedding has been decomposed and dried by the heat of fermentation. Dried manure-containing bedding and composted bedding have a low moisture content and are easier to handle than manure-containing bedding. In particular, composted bedding is less likely to emit odorous gases and is environmentally friendly because the organic matter contained in the manure has been decomposed. Note that manure-containing bedding that has been returned and mixed with a moisture regulator such as compost or sawdust to adjust the moisture is also included in the dried manure-containing bedding.
The moisture content of manure-containing litter is generally between 85% and 99%.
The moisture content of dried manure-containing litter and composted litter is 20% to 85%, preferably 30% to 80%, and particularly preferably 30% to 60%.
The moisture content of the regenerated litter obtained from such used litter is 10% to 30%, preferably 20% to 30%.

Next, the bedding regeneration device will be described.
The bedding recycling device 10 in Figure 1 produces recycled bedding from used bedding, and is equipped with a hot air generation section 20 that generates hot air, and a drying section 50 that dries the used bedding with the hot air while stirring it.

The hot air generating section 20 includes a primary hot air generating section 30 that generates primary hot air, and a secondary hot air generating section 40 that generates secondary hot air by non-contact heat exchange with the primary hot air.

The primary hot air generating section 30 has a primary hot air generator 31 that generates the primary hot air HA1, a dust collector 32 that removes dust and other debris from the primary hot air exhaust EA1, an exhaust tube 33 that discharges the primary hot air exhaust EA1, and an induction fan 34 that draws the primary hot air HA1 into the exhaust tube 33.

The primary hot air generator 31 is provided with a generator body 31a, a fuel input section 31b for inputting fuel into the generator body 31a, and a combustion fan 31c. A temperature sensor is also provided inside the generator body 31a. The fuel input section 31b is not particularly limited as long as it contains fuel and guides it to the primary hot air generator. In this embodiment, it has an input hopper 31b1 for containing fuel, and a conveyor 31b2.
The fuel for the primary hot air generator is preferably fossil fuel, biomass such as wood powder and sawdust, and solid waste fuel such as RPF (Refuse Paper & Plastic Fuel), and in particular, RPF fuel, which has stable quality, high calorie and low cost, is preferred. Biomass fuel such as sawdust is environmentally friendly, but may be difficult to obtain due to the recent increase in demand, so it is better to use waste fuel such as RPF, which is more stably supplied.

The dust collector 32 is not particularly limited, but may be, for example, a cyclone type dust collector. The dirt, dust, etc. collected by the dust collector 32 are discharged into a dust box 32b via a rotary valve 32a. By collecting the dirt, etc. from the primary hot air by the dust collector 32, pollution dust is not discharged into the atmosphere.
The induction fan 34 induces the primary hot air and also controls the temperature inside the generator body 31a of the primary hot air generator 31.

The secondary hot air generating section 40 has an air supply tube 41 that supplies air, a discharge tube 42 that discharges the generated secondary hot air HA2 to the drying device, a heat exchanger 43, and an induction fan 54 (also used as the drying section 50).
The structure of the heat exchanger 43 is not particularly limited as long as it generates secondary hot air HA2 by non-contactly transferring heat of the primary hot air HA1 to the outside air OA taken in from the air supply cylinder 41.
The induction fan 54 induces the secondary hot air HA2 and controls the temperature of the secondary hot air HA2. The induction fans 54 are provided on either side of the drying unit 50 as described below, and also serve as an induction fan for the drying unit 50.

The hot air generating section 20 generates the secondary hot air HA2 sent to the drying section 50 by non-contact heat exchange with the primary hot air HA1 generated by the primary hot air generator 31, so that components that are undesirable for livestock, such as garbage and chlorine contained in the primary hot air HA1, are not sent to the drying section 50. In other words, the garbage and other components contained in the primary hot air HA1 are not contained in the recycled bedding that is generated. In addition, the chlorine contained in the primary hot air HA1 does not affect the used bedding in the drying section 50. Therefore, the primary hot air generator has a high degree of fuel selectivity.

As shown in FIG. 1, the drying section 50 has a drying drum 51, a dust collector 52 that extracts powder and the like from the exhaust gas discharged from the drying drum 51, an exhaust pipe 53 that discharges the exhaust gas from the drying drum 51, and an induction fan 54 that draws the secondary hot air into the chimney.

As shown in Figures 1 and 2, the drying drum 51 comprises a cylindrical drum body (treatment tank) 61, an input hopper 62 (Figure 1 only) that guides used bedding into the drum body 61, a stand 63 (Figure 2 only) that supports the drum body 61, a shaft core 64 that is fixed so as to be freely rotatable within the drum body 61, a number of stirring blades 65 (Figure 1 only) that rotate around the shaft core 64 within the drum body 61, and a drive unit 66 that drives the shaft core 64.

The drum body 61 is provided with a used bedding inlet 61a at the upper side near one end (upstream side) (left side in Fig. 2a and Fig. 2b) and hot air inlets 61b1 and 61b2 for supplying secondary hot air HA2. In addition, recycled bedding (dried matter) outlets 61c1 and 61c2 are provided at the lower side near the other end (downstream side) (right side in Fig. 2a and Fig. 2b), and gas exhaust outlets 61d1 and 61d2 are provided on the upper and side sides, respectively. The drum body 61 is installed at an angle so that the upstream end is higher than the downstream end. In this embodiment, there are two hot air inlets, two gas exhaust outlets, and two outlets, but at least one of each is sufficient. However, by providing two of each, the processing time can be adjusted according to the state of the used bedding (for example, changes in moisture content, etc.).
The inclination angle of the drum body 61 is preferably 5 to 25 degrees, more preferably 10 to 20 degrees, and particularly preferably 12 to 18 degrees. If it is less than 5 degrees, the used bedding that is added tends to become stagnant. If it is more than 25 degrees, there is a risk that the used bedding that is added cannot be retained within the drum body 61 and sufficiently dried.

The length X of the drum body 61 is 1000 mm to 4000 mm, preferably 1500 mm to 3000 mm. The diameter Y of the drum body 61 is 300 mm to 1500 mm, preferably 500 mm to 1000 mm. The ratio of the diameter Y of the drum body 61 to the length X of the drum body 61 (Y/X) is 0.1 to 0.5, preferably 0.2 to 0.3.
Reference numeral 67 denotes a peephole for checking the inside state.

The input hopper 62 is not particularly limited as long as it can accommodate used bedding and guide it to the drum body 61 .
The shape and structure of the stand 63 are not particularly limited as long as it can support the drum body 61, in particular, as long as it can support the drum body 61 at an angle so that the upstream end is higher than the downstream end.

As shown in Figures 3a, 3b, and 3c, the stirring blade 65 has a rotating base 68a connected to the shaft core 64, and two blades 68b extending radially outward from the rotating base 68a at 180 degree intervals. The blade 68b has support parts 68b1 and 68b2 extending from the front and rear of the axial direction of the drum, and a plate-shaped blade part 68b3 connecting the tips of the support parts. The width direction of the plate-shaped blade part 68b3 is parallel to the radial direction of the drum body 61, and the length direction is parallel to the shaft core 64 of the drum body 61. In this way, the stirring blade 65 does not push air in the axial direction by rotating, but finely crushes and pulverizes the used bedding put into the drum. However, its shape is not particularly limited.
The multiple agitating blades 65 are arranged at equal intervals in the drum, and adjacent agitating blades 65 are installed with the blade 68b angle shifted by 90 degrees. Figure 3b shows an odd-numbered stage of agitating blades 65a, and Figure 3c shows an even-numbered stage of agitating blades 65b. In other words, the angle of the blade 68b is the same for every other stage. In this embodiment, 13 agitating blades 65 are provided, but the number is not particularly limited.

Returning to FIG. 2, the drive unit 66 is installed outside the drum and includes a motor 66a, a reduction gear 66b that connects the motor 66a to the shaft core 64, and a cover 66c that covers the reduction gear 66b. Note that the drive unit 66 is not particularly limited.

Returning to FIG. 1, the dust collector 52 is not particularly limited, and is substantially the same as the dust collector 32 of the hot air generating section 20.
The induction fan 54 guides the hot air in the drying section 50 to the chimney 53. It also controls the temperature in the drying section 50 and the temperature of the exhaust air from the drying section 50. As described above, the induction fan 54 serves both as the secondary hot air generating section and as the induction fan for the drying section 50.

In this bedding recycling apparatus 10, the dried material (recycled bedding) and powder etc. recovered from the recovery section of the drying section 50, i.e. the outlets 61c1, 61c2 of the drying drum 51 and the dust collector 52, are stored in a storage facility 55.
The powder etc. collected by the dust collector 52 may be mixed with the dried material (recycled bedding) removed from the drying section 50 to produce recycled bedding, or a powder usable as recycled bedding may be extracted from the powder etc. and mixed with the dried material to produce recycled bedding. Alternatively, the powder may be discarded as is. However, mixing the dried material with the powder to produce recycled bedding is preferable because recycled bedding can be produced without waste.

Next, the flow of this bedding recycling device 10 will be explained using FIG.
First, primary hot air HA1 is generated in primary hot air generation section 30 of hot air generation section 20. The temperature of this primary hot air HA1 is 600° C. to 1200° C., preferably 700° C. to 1000° C., and particularly preferably 800° C. to 900° C. Then, primary hot air HA1 passes through secondary hot air generation section 40 and is exhausted from exhaust tube 33 as primary hot air exhaust EA1.
Meanwhile, in the heat exchanger 43 of the secondary hot air generating section 40, the taken-in outside air OA is heated in a non-contact manner by the heat of the primary hot air HA1 to generate the secondary hot air HA2. The lower limit of the temperature of this secondary hot air HA2 is 450°C or higher, preferably 500°C or higher, and particularly preferably 550°C or higher. By setting it to 450°C or higher, it is possible to remove odors contained in the used bedding (e.g., ammonia is 500°C or higher) in the drying section 50, as described below. The upper limit of the temperature of the secondary hot air HA2 is 900°C or lower. If it is 900°C or higher, it may have an adverse effect on the material of the device. It is preferably 700°C or lower.

The secondary hot air HA2 generated by the hot air generation section 20 is supplied to the drying section 50.
In the drying section 50, the used bedding is directly dried with the secondary hot air HA2 while being agitated and crushed by the agitating blades 65. Because the drum body 61 of the drying section 50 is inclined, the used bedding is carried by gravity to the outlets 61c1, 61c2 while being agitated by the agitating blades 65. In this way, the used bedding is dried within the drying drum 51 for a predetermined time and is then removed from the outlet of the drying drum 51 as recycled bedding.
Here, the lower limit of the temperature of the exhaust air EA2 of the secondary hot air HA2 of the drying section 50 is 90° C. or higher, preferably 95° C. or higher, and particularly preferably 110° C. or higher. If it is lower than 90° C., the used bedding input cannot be sufficiently sterilized. On the other hand, the upper limit of the temperature of the exhaust air EA2 is 300° C. or lower, preferably 150° C. or lower, and particularly preferably 130° C. or lower. If it is higher than 300° C., the recycled bedding will turn into dust, which may be harmful to the health of livestock when used as recycled bedding, such as impairing their respiration.

In this way, the bedding recycling device 10 dries the used bedding while stirring it with hot air (secondary hot air HA2), so it can remove ammonia and other substances from the used bedding and produce high-quality recycled bedding. The drying time is also short.

In this bedding recycling device 10, hot air (secondary hot air) is generated using the hot air generating section 20, but the method for generating hot air is not particularly limited.
In addition, in this bedding recycling device 10, the used bedding is directly dried with hot air (secondary hot air), but the method of drying is not particularly limited. For example, the used bedding may be indirectly dried with hot air, i.e., without contact. In that case, hot air generated by a primary hot air generator may be sent to the drying section.

LIST OF SYMBOLS 10 bedding recycling device 20 hot air generation section 30 primary hot air generation section 31 primary hot air generator 31a generator body 31b fuel input section 31b1 input hopper 31b2 conveyor 31c combustion fan 32 dust collector 32a rotary valve 32b dust box 33 exhaust stack 34 induced draft fan 40 secondary hot air generation section 41 air supply stack 42 exhaust stack 43 heat exchanger 50 drying section 51 drying drum 52 dust collector 53 exhaust stack 54 induced draft fan 55 storage 61 drum body 61a input port 61b1, 61b2 hot air inlet 61c1, 61c2 outlet 61d1, 61d2 gas exhaust port 62 input hopper 63 stand 64 Shaft core 65, 65a, 65b Agitating blade 66 Driving device 66a Motor 66b Reduction gear 66c Cover 68a Rotating base 68b Blade 68b1, 68b2 Support portion 68b3 Blade portion HA1 Primary hot air EA1 Exhaust of primary hot air HA2 Secondary hot air EA2 Exhaust of secondary hot air OA Outside air

Claims (6)

A hot air generating unit that generates hot air of 500°C or higher ;
The processing tank is cylindrical and obliquely installed so that the end where the outlet for removing the recycled bedding is provided is lower than the end where the used bedding is fed in, and has an internal processing tank with stirring blades, and a drying section that directly dries the used bedding with the hot air while stirring it to produce the recycled bedding.
Litter recycling device. The used bedding is a dried feces-containing bedding obtained by drying feces-containing bedding or a composted bedding obtained by fermenting and drying feces-containing bedding.
The litter regeneration device according to claim 1. The moisture content of the used litter is 20% to 85%.
The bedding regeneration device according to claim 1 or 2. The exhaust temperature of the drying section is 90°C or higher.
A bedding regeneration device according to any one of claims 1 to 3 . A dust collector is provided for extracting powder from the exhaust gas of the drying section,
The powder collected by the dust collector is taken out as the recycled bedding.
A bedding regeneration device according to any one of claims 1 to 4 . A hot air generating step of generating hot air of 500°C or higher;
and a drying step in which the used bedding is directly dried with the hot air while being stirred by a stirring blade in a processing tank that is cylindrical and obliquely installed so that the end of the processing tank where the used bedding is fed is lower than the end of the processing tank where the recycled bedding is fed.
Litter regeneration methods.

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