Drying system and drying method

Abstract

This system provides a way to reduce fuel costs for drying livestock waste. [Solution] A drying treatment system 10 comprising a first hot air generator 21, a hot air generating unit 20 that generates hot air HA, and a drying unit 50 that generates processed material DB by drying processed material UB derived from livestock excrement with the hot air while stirring, wherein the first hot air generator generates the hot air using at least the processed material as fuel.

Description

Technical Field

[0001] The present invention relates to a system and method for drying a material to be treated derived from livestock excrement.

Background Art

[0002] Livestock excrement is generally treated together with bedding spread on the floor of a livestock house. The bedding is used for the purpose of improving the livability of livestock and absorbing excrement to improve the handling property of excrement. As the bedding, for example, dried grass, straws (rice straw), sawdust (wood chips), rice husks, etc. are used. Such bedding finishes its role when it absorbs the moisture of excrement and becomes saturated. For example, in a dairy cattle breeding facility, it becomes saturated in a few days. The used bedding in a saturated state needs to be properly treated.

[0003] Patent Documents 1 and 2 disclose a bedding regeneration device that regenerates bedding into a bedding safe for livestock by drying it with hot air at a high temperature while stirring the used bedding. With that device, it is possible to produce alternative bedding that replaces dried grass, straws, sawdust, rice husks, etc. that have limited supply stability and whose prices are soaring due to the demand for biomass power generation.

[0004] Further, Patent Document 3 describes a method for regenerating livestock bedding that can be reused as bedding by sequentially sun-drying, fermenting, and forced-air drying used livestock bedding. Patent Document 4 describes a method for reusing livestock manure and used bedding as livestock bedding by sequentially sterilizing, fermenting, and drying them. The methods described in Patent Documents 3 and 4 include a fermentation step, and Patent Documents 3 and 4 also describe that the regenerated bedding can be used as compost.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] The bedding recycling equipment described in Patent Documents 1 and 2 can use fossil fuels, biomass such as wood flour and sawdust, and waste solid fuels such as RPF (Refuse Paper & Plastic Fuel) as fuel. However, in recent years, energy prices in general, including biomass fuels, RPF, and kerosene, a common fuel, have risen, increasing the cost of generating hot air.

[0007] Furthermore, regarding recycled alternative bedding and compost, securing storage space and the costs of transporting unused material off-site are problematic, and there is a need for efficient methods to reduce their volume.

[0008] The present invention has been made in consideration of the above, and aims to provide a drying system and method that can reduce fuel costs when drying materials derived from livestock excrement, such as used bedding. [Means for solving the problem]

[0009] To address the above issues, the drying system and method of the present invention uses a portion of the dried material obtained from livestock excrement as fuel for generating hot air.

[0010] Specifically, the drying system of the present invention has a first hot air generator, comprising a hot air generating unit that generates hot air, and a drying unit that produces a processed product by drying a material to be processed from livestock excrement with the hot air while stirring it, wherein the first hot air generator generates the hot air using at least the processed product as fuel.

[0011] Preferably, in the above drying system, the material to be processed includes used bedding containing livestock excrement.

[0012] Preferably, in any of the above drying systems, the material to be treated includes compost derived from livestock excrement.

[0013] Preferably, in any of the above drying systems, the hot air generating unit further comprises a second hot air generating unit that generates starting hot air to raise the temperature of the first hot air generating unit.

[0014] Preferably, in any of the above drying systems, the first hot air generator is a fluidized bed type device.

[0015] Preferably, in any of the above drying systems, the first hot air generator has an auxiliary heating means downstream of the input section for the material to be processed.

[0016] Preferably, any of the above drying systems further includes a material transport unit that transports the material from the drying unit to the first hot air generator.

[0017] The drying method of the present invention comprises a hot air generation step of generating hot air using a first hot air generator, and a drying step of producing a processed product by drying a material to be processed from livestock excrement with the hot air while stirring it, wherein the first hot air generator generates the hot air using at least the processed product as fuel.

[0018] Preferably, in the above drying method, the hot air generation step includes a first step of generating hot air using an auxiliary heating means provided in the first hot air generator while sending starting hot air generated by the second hot air generator to the first hot air generator to raise the temperature of the first hot air generator, and generating the hot air, and a second step of generating the hot air by burning the workpiece in the first hot air generator while sending outside air to the first hot air generator. [Effects of the Invention]

[0019] According to the drying treatment system or method of the present invention, since a part of the processed material obtained by drying the material to be processed derived from livestock excrement is used as fuel for generating hot air, the fuel cost for drying treatment can be reduced. Further, by using the processed material, which is biomass fuel instead of fossil fuel, as fuel for generating hot air, the carbon dioxide emission can be reduced.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic diagram showing the configuration of the drying treatment system of the first embodiment. [Figure 2] It is a schematic diagram showing the structure of the first hot air generator of the first embodiment. [Figure 3] It is A: a plan view and B: a side view of the drying drum of the drying section. [Figure 4] A: A side cross-sectional view showing the drum body, and B - C: schematic diagrams showing the posture of the stirring blades. [Figure 5] It is a schematic diagram showing the configuration of the drying treatment system of the second embodiment. [Figure 6] It is a schematic diagram showing the structure of the first hot air generator of the second embodiment.

Modes for Carrying Out the Invention

[0021] The first embodiment of the drying treatment system and method of the present invention will be described based on FIGS. 1 to 4.

[0022] The materials to be processed targeted by the drying treatment system and method of the present embodiment are derived from livestock excrement such as used dressings containing livestock excrement, compost obtained by fermenting livestock excrement, and organic substances including livestock excrement. In the following, the case of drying used dressings as the material to be processed will be described.

[0023] Used bedding refers to bedding that contains livestock manure as a result of use. Examples include manure-containing bedding removed from cattle barns, etc., and dried manure-containing bedding obtained by evaporating the moisture from manure-containing bedding through ventilation or sunlight. Dried manure-containing bedding is also included when manure-containing bedding is returned to the animal and mixed with moisture-adjusting agents such as compost or sawdust to adjust the moisture content. Generally, the moisture content of manure-containing bedding is 85% to 99%, and the moisture content of dried manure-containing bedding is 20% to 85%.

[0024] Referring to Figure 1, the drying system 10 dries used bedding material UB and comprises a hot air generating unit 20 that generates hot air HA and a drying unit 50 that dries the used bedding material UB with the hot air HA while stirring it. The drying system 10 also comprises a processed material transport unit 40 that transports the processed material DB, which is the dried used bedding material UB, from the drying unit 50 to the hot air generating unit 20. In the following, the drying system 10 may be simply referred to as the processing system.

[0025] The hot air generating unit 20 includes a first hot air generator 21 and an air supply unit 30 that supplies air to the first hot air generator 21. The air supply unit 30 is equipped with a second hot air generator 32, which generates starting hot air SA to raise the temperature of the first hot air generator 21 when the processing system 10 is started.

[0026] The first hot air generator 21, the second hot air generator 32, and the drying drum 51 of the drying section 50 are connected to each other by piping. The piping connecting the first hot air generator 21 and the drying drum 51 supplies hot air HA from the former to the latter, and valve 37 in the middle is always kept open. The piping connecting the second hot air generator 32 and the first hot air generator 21 supplies outside air OA or starting hot air SA from the former to the latter, and valve 36 in the middle is always kept open. The piping connecting the second hot air generator 32 and the drying drum 51 is an emergency piping, and valve 38 in the middle is always kept closed. As a result, the second hot air generator 32 and the first hot air generator 21 are always connected in series. The following explanation will continue assuming that valves 36 and 37 are open and valve 38 is closed.

[0027] The piping connecting the second hot air generator 32 and the drying drum 51 is used when performing maintenance on the first hot air generator 21. Specifically, by opening valve 38 and closing valves 36 and 37, hot air can be supplied from the second hot air generator 32 to the drying drum 51 to dry the used bedding material UB.

[0028] Referring to Figures 1 and 2, the first hot air generator 21 has a shaft-shaped body, an air inlet 22 at the bottom, a fuel inlet 23 above it which serves as the input for the processed material DB which is the fuel, and an auxiliary burner (auxiliary heating means) 26 near the hot air outlet at the top. During steady-state operation, the first hot air generator 21 burns the fuel supplied into the device from the fuel inlet 23 to heat the air introduced from the air inlet 22 and generate hot air HA. The fuel for generating the hot air HA includes at least the processed material DB, which is used bedding material UB that has been dried.

[0029] The first hot air generator 21 is preferably a fluidized bed type device, which heats the air by flowing a heat transfer medium such as sand within the device. Fluidized bed type devices are energy efficient, and the temperature of the generated hot air HA tends to remain stable even if the moisture content of the fuel fluctuates.

[0030] Air is supplied to the air inlet 22 from the air supply unit 30 to fluidize the heat transfer medium such as sand in the first hot air generator 21. In addition, when the processing system 10 is started, the starting hot air SA generated by the second hot air generator 32 of the air supply unit 30 is supplied to the air inlet 22 in order to raise the temperature of the first hot air generator 21. The configuration of the air supply unit 30 will be described later.

[0031] The fuel input unit 23 introduces fuel for generating hot air HA into the first hot air generator 21. Hereinafter, the fuel introduced from the fuel input unit 23 will be referred to as the main fuel. The main fuel burns in the first hot air generator, heating the air introduced from the air introduction unit 22 to generate hot air HA. The fuel input unit 23 has an input hopper 24 and an input conveyor 25. The main fuel, after passing from the input hopper 24 and through the input conveyor 25, is blown into the first hot air generator 21 using air from the suction blower 43 of the processed material transport unit 40.

[0032] The main fuel includes, at least in part, processed material DB obtained by drying used bedding material UB. The processed material DB used as the main fuel may be stored after drying, or, preferably, a portion of the processed material DB is transported from the drying unit 50 while the drying process is being carried out. The configuration of the processed material transport unit 40 that transports the processed material DB from the drying unit 50 will be described later.

[0033] The main fuel may include compost derived from livestock waste. Preferably, the main fuel consists of dried used bedding material DB and compost derived from livestock waste, and more preferably consists of dried used bedding material DB.

[0034] The main fuel may also contain other fuels. However, since the processed material DB dried in the drying section 50 can be returned to the barn as recycled bedding, the main fuel should be one that does not contaminate the processed material DB even if the hot air HA comes into direct contact with the used bedding UB.

[0035] The moisture content of the main fuel is preferably 45% or less, more preferably 40% or less, and particularly preferably 35% or less. The moisture content of the processed material DB of the used bedding treated in the drying section 50 is 10% to 50%, and the moisture content of the composted bedding is generally 10% to 50%.

[0036] The auxiliary burner 26 is located downstream of the fuel input section 23 (upper side in Figure 2), preferably near the outlet of the first hot air generator 21. The auxiliary burner 26 is preferably a kerosene burner, supplied with kerosene fuel from the kerosene supply source 28 and outside air from the combustion fan 27.

[0037] The auxiliary burner 26 is used to heat the hot air HA when the temperature of the hot air HA decreases due to fluctuations in the moisture content of the main fuel during steady operation of the first hot air generator 21.

[0038] Furthermore, the auxiliary burner 26 is also used when starting the processing system 10. When the first hot air generator 21 is heated up, the starting hot air SA introduced from the air inlet 22 loses heat to various parts of the first hot air generator and to heat transfer media such as sand, causing its temperature to drop. Therefore, the auxiliary burner can be used to heat it, allowing the first hot air generator to produce hot air HA at the required temperature.

[0039] In particular, when a fluidized bed type device is used as the first hot air generator 21, the temperature of the hot air HA is easily stabilized by the heat transfer medium with a large heat capacity, but there is a problem that it takes a long time to heat up. Even if the first hot air generator 21 is a fluidized bed type device, by using an auxiliary burner 26, it becomes possible to dry the used bedding material UB in the drying section 50 from an early stage of heating up the first hot air generator 21, thus avoiding wasting time and fuel for heating.

[0040] A cooling damper 29 is connected to the piping at the outlet of the first hot air generator 21. By opening the cooling damper 29 and drawing in outside air OA, the outside air OA can be mixed with the hot air HA, thereby lowering the temperature of the hot air HA. The cooling damper 29 is used to cool the hot air HA when the temperature of the hot air HA rises too high during steady operation of the first hot air generator 21, for example, when the moisture content of the main fuel becomes low due to fluctuations. When the temperature of the hot air HA is within a predetermined range, the cooling damper is kept closed.

[0041] The method of cooling the hot air HA is not limited to using a damper. For example, outside air OA may be drawn in using a fan and mixed with the hot air HA. Alternatively, the hot air HA may be cooled by passing it through a heat exchanger with outside air OA. Alternatively, the hot air HA may be cooled by passing it through a heat exchanger with a gas or liquid that is cooler than the hot air HA, other than outside air.

[0042] Referring to Figure 1, the air supply unit 30 includes a push fan 31 for taking in outside air OA and a second hot air generator 32. The second hot air generator 32 has a kerosene burner 33 as a heating means.

[0043] The push fan 31 can send a portion of the incoming outside air OA to the combustion fan 34 of the kerosene burner 33. When the processing system 10 is started, the kerosene burner 33 is supplied with kerosene fuel from the kerosene supply source 35 and outside air from the combustion fan 34, heating the air in the second hot air generator 32 to generate starting hot air SA. The starting hot air SA is then guided from the second hot air generator 32 to the air inlet 22 of the first hot air generator 21.

[0044] The heating means of the second hot air generator 32 is not limited to a kerosene burner; burners that burn various fossil fuels such as natural gas and liquefied petroleum gas, or biofuels, can be used. Preferably, the second hot air generator 32 uses a fuel that does not contain water. Examples of water-free fuels include fossil fuels, bioethanol, and biogas. This is because it is desirable for the second hot air generator 32 to have a rapid rise in temperature of the starting hot air SA and to be easy to control the heat output. More preferably, the second hot air generator 32 uses fossil fuels, and particularly preferably kerosene. This is because it has a stable supply and is easily available.

[0045] During steady-state operation of the processing system 10, when the kerosene burner 33 is not in use, the entire volume of outside air OA taken in by the push fan 31 is guided to the second hot air generator 32, and the outside air OA can be sent directly from the second hot air generator 32 to the first hot air generator 21 without being heated.

[0046] The drying unit 50 includes a drying drum 51, an input hopper 52 and input conveyor 53 for loading used bedding material UB into the drying drum, dust collectors 54 and 55 for removing powder and the like from the exhaust EA discharged from the drying drum 51, an induction fan 56 for drawing in the exhaust EA from the drying drum 51, and a processed material conveyor 57 for transporting the processed material removed from the drying drum 51.

[0047] Referring to Figures 3 and 4, the drying drum 51 has a cylindrical drum body (processing tank) 61 supported by a frame 62. The drum body 61 is installed at an angle such that the upstream end, i.e., the end into which the used bedding material UB is introduced, is higher than the downstream end, i.e., the end from which the processed material DB is removed. The shape and structure of the frame 62 are not particularly limited as long as it can support the drum body 61, and in particular, as long as it can support the drum body 61 at an angle such that the upstream end is higher than the downstream end.

[0048] 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 material UB that is put in tends to accumulate. If it is greater than 25 degrees, there is a risk that the used bedding material that is put in will not be able to be held inside the drum body 61 and dried sufficiently.

[0049] The length X of the drum body 61 is 1000mm to 3000mm, preferably 1500mm to 2100mm. The diameter Y of the drum body 61 is 210mm to 1500mm, preferably 500mm to 1000mm. The ratio of the diameter Y (Y / X) of the drum body 61 to the length X is 0.1 to 0.5, preferably 0.2 to 0.3.

[0050] The drum body 61 is equipped with an inlet 63 for used bedding material and a hot air inlet 64 for supplying hot air HA on the upper side near one end (upstream side). On the lower side near the other end (downstream side), there is an outlet 65 for the dried processed material DB, and gas exhaust ports 66 are provided on the top and sides. In Figure 3, two hot air inlets 64, two gas exhaust ports 66, and two outlets 65 are depicted, but at least one of each is sufficient. However, by providing two of each, the processing time can be adjusted according to the condition of the used bedding material UB, such as changes in moisture content. Reference numeral 67 denotes a viewing window for checking the internal condition.

[0051] The drum body 61 comprises a shaft 70 that is fixed to rotate freely within the drum body 61, a plurality of stirring blades 71 that are attached to the shaft 70 within the drum body 61 and rotate around the shaft 70, and a drive device 76 that drives the shaft 70.

[0052] As shown in Figure 4, the stirring blade 71 consists of a rotating base 72 connected to the shaft 70, and two blades 73 extending radially outward from the rotating base 72 at 180-degree intervals. Each blade 73 has support parts 74, 74 extending from the front and rear in the axial direction of the drum body, and a plate-shaped blade part 75 connecting the tips of these support parts. The plate-shaped blade part 75 has a width parallel to the radial direction of the drum body 61 and a length parallel to the shaft 70 of the drum body 61. Thus, the stirring blade 71 does not push air in the axial direction by rotating, but rather finely crushes and grinds the used bedding material UB that has been put into the drum body. However, the shape of the stirring blade 71 is not particularly limited.

[0053] Multiple stirring blades 71 are arranged at equal intervals in the axial direction within the drum body 61, and adjacent stirring blades 71 are set with the angle of the blades 73 offset by 90 degrees. Figure 4B shows odd-numbered stages of stirring blades 71, and Figure 4C shows even-numbered stages of stirring blades 71. In other words, the angles of the blades 73 coincide every other blade. In this embodiment, 13 stirring blades 71 are provided, but the number is not particularly limited.

[0054] The drive unit 76 is installed outside the drum body 61 and includes a motor 77, a reduction gear 78 connecting the motor 77 to the shaft 70, and a cover 79 covering the reduction gear 78. The type and structure of the drive unit 76 are not particularly limited.

[0055] Returning to Figure 1, the input hopper 52 and input conveyor 53 are not particularly limited in their form, as long as they collect the used bedding material UB and guide it to the drum body of the drying drum 51.

[0056] The processed material DB, which has been dried in the drying drum 51, is collected from the outlet (65 in Figure 3B) and transported to the temporary processing area 58 by the processing material conveyor 57. The processed material DB is then removed from the temporary processing area 58 and stored in silos or other containers, or returned to the livestock barn as recycled bedding.

[0057] The exhaust gas EA discharged from the gas exhaust port (66 in Figure 3) of the drying drum 51 is released into the atmosphere through dust collectors 54 and 55 and an induced draft fan 56. The temperature of the exhaust gas EA from the drying drum 51 can be controlled by changing the output of the induced draft fan 56 to control the amount of induced draft. The dust collectors 54 and 55 are not particularly limited in type, but for example, they are cyclone-type dust collectors. Since the exhaust gas from the drying drum 51 contains a large amount of powdery material DB, the material DB collected by the dust collectors 54 and 55 is returned to the material conveyor 57. If an appropriate dust collector is selected, almost all of the material DB in the exhaust gas will be collected by the preceding dust collector 54, so the subsequent dust collector 55 mainly functions to purify the exhaust gas before it is released into the atmosphere.

[0058] The material transport unit 40 includes a transport pipe 41, a dust collector 42, and a suction blower 43. The material transport unit 40 transports the material DB pneumatically from the drying unit 50 to the first hot air generator 21.

[0059] The transport pipe 41 has its inlet facing near the end of the material conveyor 57 and sucks up the material DB on the material conveyor. The material transported through the transport pipe 41 goes to the dust collector 42 and is discharged into the main fuel input hopper (24 in Figure 2). The suction blower 43 generates an airflow that flows through the transport pipe 41.

[0060] The processed material transport unit 40 can be omitted, but by including the processed material transport unit in the processing system 10, the used bedding material UB can be dried in the drying unit 50, and the processed material DB can be directly transported to the first hot air generator 21 and used as the main fuel.

[0061] Next, the drying process method of this embodiment will be described. This process is carried out using the drying process system 10 described above and includes a hot air generation step and a drying step for drying the used bedding material UB. The reference numerals for each part are shown in Figures 1 to 4.

[0062] First, let me explain the drying process.

[0063] In the drying section 50, used bedding material UB is placed in the drying drum 51, and hot air HA generated by the first hot air generator 21 is supplied. Inside the drying drum 51, the used bedding material UB is agitated and crushed by the stirring blades 71 while being dried by the hot air HA applied directly. Because the drum body 61 of the drying drum 51 is inclined, the used bedding material is agitated by the stirring blades 71 and carried to the outlet 65 by gravity. In this way, the used bedding material is dried inside the drying drum 51 for a predetermined time.

[0064] The temperature of the hot air HA supplied to the drying drum 51 is usually 400°C or higher, preferably 450°C or higher, more preferably 500°C or higher, and particularly preferably 550°C or higher. By setting the temperature of the hot air HA to 400°C or higher, odors contained in the used bedding material UB (for example, ammonia at 500°C or higher) can be removed. The temperature of the hot air HA is preferably 900°C or lower. If the hot air temperature is 900°C or higher, it may adversely affect the material of the device. The temperature of the hot air HA is more preferably 700°C or lower.

[0065] The temperature of the exhaust EA discharged from the drying drum 51 is preferably 90°C or higher, more preferably 95°C or higher, and particularly preferably 110°C or higher. If the temperature of the exhaust EA is lower than 90°C, the used bedding material being introduced cannot be sufficiently sterilized. On the other hand, the temperature of the exhaust EA is preferably 300°C or lower, more preferably 150°C or lower, and particularly preferably 130°C or lower. If the temperature of the exhaust EA is higher than 300°C, the processed material DB may turn into dust, which may harm the health of livestock, such as damaging their respiratory system, when used as recycled bedding material. The temperature of the exhaust EA can be adjusted by changing the output of the induced draft fan 56 to control the airflow velocity inside the drying drum 51.

[0066] The dried used bedding material DB is collected from the outlet of the drying drum 51 (65 in Figure 3B), and a portion is collected from the exhaust EA by dust collectors 54 and 55, and then transported to the temporary storage area 58 by the processed material conveyor 57. The drying process is carried out under conditions that reduce the moisture content of the processed material to 10% to 30%, preferably 20% to 30%.

[0067] The hot air generation process is the process of generating hot air HA using the first hot air generator 21. The hot air generation process is divided into two stages: the first stage during startup, which involves raising the temperature of the first hot air generator 21, and the second stage during steady-state operation after the first hot air generator 21 has been heated.

[0068] In the first stage of startup, the second hot air generator 32 of the air supply unit 30 heats the outside air OA to generate starting hot air SA, which is supplied to the air inlet 22 of the first hot air generator 21. The starting hot air SA heats the various parts of the first hot air generator and the sand inside. The temperature of the starting hot air SA supplied to the first hot air generator 21 is 200°C to 800°C, preferably 500°C to 700°C. As the starting hot air SA loses heat to the various parts of the first hot air generator and the sand, its temperature decreases, so the auxiliary burner 26 heats it to raise the temperature of the hot air HA coming out of the first hot air generator to a predetermined temperature. This allows the hot air HA generated during startup to also be used for drying the used bedding material UB in the drying unit 50.

[0069] Once the first hot air generator 21 has reached a sufficient temperature, specifically exceeding the ignition temperature of the material DB, which is 200-250°C, it moves from the first stage to the second stage of steady-state operation. When the kerosene burner 33 of the air supply unit 30 is stopped, the outside air OA taken in by the push fan 31 passes through the second hot air generator 32, but without being heated except for preheating, and is supplied to the air inlet 22 of the first hot air generator 21. In this state, the main fuel is supplied from the fuel input unit 23 of the first hot air generator 21 and combusted.

[0070] The main fuel is transported from the first stage of the hot air generation process, while drying the used bedding material UB, to the input hopper 24 from the processing material conveyor 57. Even after moving to the second stage of the hot air generation process, the weight of the processing material DB in the input hopper 24 is monitored, and processing material DB is transported from the processing material conveyor 57 to replenish it as needed.

[0071] The processed material DB used as the main fuel may be processed material DB that has been stored from a previously carried out drying process. In addition to processed material DB, compost made from dried and fermented livestock manure may be added to the main fuel. Other fuels besides processed material DB and compost may also be added to the main fuel. The moisture content of the main fuel is preferably 45% or less, more preferably 40% or less, and particularly preferably 35% or less, as described above.

[0072] As described above, the hot air generating unit 20 has three heating means, namely, combustion of the main fuel, the kerosene burner 33 of the air supply unit 30, and the auxiliary burner 26. In the first stage of the hot air generation process, the kerosene burner 33 and the auxiliary burner 26 are used to generate hot air HA, and in the second stage, the main fuel is used for combustion and, if necessary, the auxiliary burner 26 is used to generate hot air HA. When using a fluidized bed type first hot air generating device, in a typical operating example, the first 3 to 4 hours of a total 10 hours of operation are the first stage, and the remaining 6 to 7 hours are the second stage.

[0073] Next, a second embodiment of the drying system and method of the present invention will be described.

[0074] Referring to Figures 5 and 6, the drying system 10A of this embodiment does not include the air supply unit 30 of the first embodiment shown in Figure 1, nor does it include the second hot air generator 32 within the air supply unit.

[0075] The first hot air generator 21A of the hot air generating unit 20A receives outside air directly from the push fan 31A to the air inlet 22, without passing through the second hot air generator (32 in the first embodiment). A kerosene burner 33A is provided just above the air inlet 22.

[0076] When the processing system 10A is started, kerosene fuel is supplied to the kerosene burner 33A from the kerosene supply source 35A, and a portion of the outside air OA taken in by the push fan 31A is supplied by the combustion fan 34A, raising the temperature of the first hot air generator 21A by the heat of combustion of the kerosene. During steady operation after the first hot air generator 21A has reached a certain temperature, the kerosene burner 33A is extinguished, and the main fuel introduced from the fuel input section 23 is burned to heat the air introduced from the air introduction section 22 and generate hot air HA. In this embodiment as well, the main fuel includes at least the material to be processed DB.

[0077] Components denoted by the same reference numerals in the drying system 10 of the first embodiment and the drying system 10A of this embodiment have the same function. Furthermore, the description of the kerosene burner 33 and its fuel in the first embodiment also applies to the kerosene burner 33A of this embodiment.

[0078] According to the drying method of the above embodiment, when drying a material to be treated derived from livestock excrement, a portion of the treated material obtained by the drying process is used as fuel for generating hot air, thus reducing fuel costs.

[0079] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of its technical concept. [Explanation of symbols]

[0080] 10, 10A Drying System 20, 20A Hot air generating unit 21, 21A First hot air generator 22 Air intake section 23 Fuel input section 24 Input Hopper 25 Input conveyor 26. Auxiliary burner (auxiliary heating means) 27 Combustion fan 28 Kerosene supply sources 29 Cooling damper 30 Air supply unit 31, 31A Push-in fan 32. Second Hot Air Generator 33, 33A kerosene burner 34, 34A Combustion Fan 35, 35A Kerosene supply source 36, 37, 38 valves 40 Processing and Transport Department 41 Transport pipe 42 Dust collector 43. Suction Blower 50 Drying section 51 Drying Drum 52 Input hopper 53 Input conveyor 54, 55 Dust collector 56 Inducing Fan 57. Material conveyor 58 Temporary storage area for processed materials 61 Drum body (processing tank) 62 mounting bases 63 Used bedding disposal slot 64 Hot air inlet 65 Outlet 66 Gas exhaust port 67 Peephole 70 axis 71 Agitator blade 72 RPM base 73 Wings 74 Support part 75 Blade section 76 Drive unit 77 Motor 78 Reduction gear 79 Cover DB Processing Items EA exhaust HA hot air OA outside air SA Starting Hot Air UB Used bedding material (material to be processed) X Length of the drum body Y Drum body diameter

Claims

1. It has a first hot air generating device, a hot air generating unit that generates hot air, The system includes a drying unit which produces a processed product by drying a material derived from livestock excrement with hot air while stirring it, The first hot air generating device generates the hot air using at least the processed material as fuel. Drying system.

2. The material to be processed includes used bedding containing livestock excrement. The drying process system according to claim 1.

3. The material to be treated includes compost derived from livestock excrement. The drying process system according to claim 1.

4. The hot air generating unit further includes a second hot air generating device that generates starting hot air to raise the temperature of the first hot air generating device. The drying process system according to claim 1.

5. The first hot air generating device is a fluidized bed type device. The drying process system according to claim 1.

6. The first hot air generator has an auxiliary heating means downstream of the input section for the processed material. The drying process system according to claim 1.

7. The system further includes a material transport unit that transports the processed material from the drying unit to the first hot air generator. The drying process system according to claim 1.

8. A hot air generation process in which hot air is generated by a first hot air generating device, The process includes a drying step in which a material to be treated, derived from livestock excrement, is dried with hot air while being stirred to produce a treated product. The first hot air generating device generates the hot air using at least the processed material as fuel. Drying method.

9. The aforementioned hot air generation process is: The first step involves sending the starting hot air generated by the second hot air generator to the first hot air generator to raise the temperature of the first hot air generator, while generating the hot air using an auxiliary heating means provided in the first hot air generator. The process includes a second step of generating hot air by burning the material to be processed within the first hot air generator while supplying outside air to the first hot air generator, The drying method according to claim 8.

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