JP7556673B2 - Sludge heat recovery device, sludge heat recovery system, and sludge heat utilization factory - Google Patents

Description

The present invention relates to a sludge heat recovery device, a sludge heat recovery system, and a factory that utilizes sludge heat.

Various devices and methods are known for processing sludge into fuel for boilers (see Patent Documents 1 to 6).

Patent document 1 describes a method for producing fuel using organic sludge, which includes a dehydration process in which the organic sludge is dehydrated to form dehydrated sludge, and a mixing process in which the dehydrated sludge is mixed with at least one of wood chips and sawdust to form wood mixed sludge.
Furthermore, Patent Document 1 describes a sludge reuse system that uses the produced fuel, in which organic sludge is dehydrated at a sludge treatment plant, the dehydrated sludge is transported by vehicle to a fuel production facility, the dehydrated sludge is mixed with at least one of small wood chips and sawdust at the fuel production facility to produce fuel, the fuel is transported by vehicle to a combustion facility, and the fuel is combusted at the combustion facility.

Patent Document 2 describes a method for producing biomass fuel that includes a dephosphorization process for removing phosphorus from sewage sludge and a carbonization process for carbonizing the sewage sludge to produce fuel. In the dephosphorization process, the sewage sludge is stirred in an alkaline solution and then filtered and separated. The dephosphorized sewage sludge obtained by filtration and separation is converted into carbonized fuel. On the other hand, gypsum is added to the solution obtained by filtration and separation, the pH is set to 13.0 to 14.9 at the start of the reaction, the solution is stirred at 40 to 100°C, and the pH is maintained at 12 or higher at the end of the reaction, causing the phosphoric acid in the alkaline solution to react with the gypsum to produce an adsorbent mainly composed of hydroxyapatite crystals.

Patent Document 3 describes a method for producing solid fuel in which organic waste such as sewage sludge, paper sludge, and food sludge is dried to a moisture content of 20-60%, granulated, and carbonized in an air-tight rotary kiln at a carbonization temperature of 300-600°C for 4-22 minutes, then immediately cooled, and the cooled carbonized material is dried at a drying temperature of 70°C to 150°C for 2-7 hours.

Patent document 4 describes a solid fuel derived from organic sludge, which is obtained by drying and carbonizing the organic sludge, and has an atomic ratio H/C of hydrogen to carbon of 0.8 to 1.8, and is a solid fuel that can be burned together with coal.

Patent Document 5 describes a method for producing solid fuel, in which the organic waste is anaerobic digestion sludge or sludge generated at a sewage treatment plant, the raw materials for producing RPF (Refuse Paper & Plastic Fuel) contain a total of 50% by mass or more of plastic and/or paper, and the mixture ratio of the organic waste to the total mass of the organic waste and the raw materials for producing RPF is adjusted so as to satisfy the following formula (I), where the moisture content of the organic waste is x (mass %) and the ratio (mass %) of the mass of the organic waste to the total mass of the organic waste and the raw materials for producing RPF is y, and the method includes a mixing step for obtaining a mixed raw material containing these, and a molding step for obtaining a molded body from the mixed raw material.
Formula (I): y≦-0.0436x ² +1.7458x+40.0

Patent Document 6 describes a method for producing solid fuel, which includes an aging process in which sewage sludge, human waste sludge, food waste, livestock waste, or digested sludge of these is dried to adjust the moisture content to 20-50% by mass, and the organic waste is kept in an atmosphere at a temperature of 20-65°C for 12-120 hours to obtain aged waste, a mixing process in which a mixed raw material containing the aged waste and RPF production raw material containing 50% or more by mass of plastic and/or paper in total is obtained, and a molding process in which a molded body is obtained from the mixed raw material.

JP 2015-25054 A Patent No. 5001594 Patent No. 4368964 JP 2007-119641 A Patent No. 6022259 Patent No. 6047337

However, the methods described in Patent Documents 1 and 2 have the problem that the transportation costs are high because the fuel produced from the dried sludge must be transported to the combustion facility by vehicle, and odors and dust are generated when the fuel produced from the dried sludge is transported.
The methods described in Patent Documents 3 and 4 involve granulating organic waste such as sewage sludge and then carbonizing it using a rotary kiln or the like to produce solid fuel, but no consideration has been given to reducing the transportation costs involved in transporting the resulting solid fuel to a combustion facility.
The methods described in Patent Documents 5 and 6 involve mixing organic waste such as sewage sludge with raw materials for RPF production to produce molded solid fuel, but no consideration has been given to reducing the transportation costs involved in transporting the resulting solid fuel to a combustion facility.

The problem that the present invention aims to solve is to provide an apparatus and system that can reduce the cost of transporting dried sludge, suppress odors and dust when transporting dried sludge, and recover the heat contained in sludge into electric thermal energy without using special sludge fuel conversion equipment.
Another problem to be solved by the present invention is to provide a sludge heat recovery system and a sludge heat utilization factory that include the above-mentioned sludge heat recovery device.

The specific configuration of the present invention, which is a means for solving the above problems, and the preferred configuration of the present invention are described below.

[1] At least a conveying unit and a solid fuel boiler are provided in this order;
A sludge heat recovery device, wherein the conveying section conveys at least the dried sludge to a solid fuel boiler.
[2] The sludge heat recovery apparatus according to [1], wherein the moisture content of the dried sludge is 5 to 40 mass%.
[3] The sludge heat recovery apparatus according to [1] or [2], wherein the transport section transports RPF or coal containing at least one of plastic, paper, and paper sludge, and dried sludge to a solid fuel boiler.
[4] The sludge heat recovery apparatus according to any one of [1] to [3], further comprising a sludge drying section, wherein dried sludge is obtained in the sludge drying section.
[5] A sludge heat recovery apparatus according to any one of [1] to [4], wherein the transport section has a crushing means for dried sludge, or further comprises a sludge drying section, and the sludge drying section has a crushing means for dried sludge.
[6] The sludge heat recovery device according to any one of [ ¹ ] to [ ^5] , wherein the dried sludge satisfies the following condition 1A, condition 1B, or condition 1C, where Q1 is the total net calorific value of all fuels supplied to the solid fuel boiler, and Q2 is the net calorific value of the dried sludge:
Condition 1A: The moisture content of the dried sludge is 20 mass % or less, and the value of 100%×Q ² /Q ¹ is 40% or less.
Condition 1B: The moisture content of the dried sludge is more than 20 mass % and not more than 30 mass %, and the value of 100%×Q ² /Q ¹ is not more than 20%.
Condition 1C: The moisture content of the dried sludge is more than 30 mass % and not more than 40 mass %, and the value of 100%×Q ² /Q ¹ is not more than 10%.
[7] The sludge heat recovery apparatus according to any one of [1] to [6], wherein the transport unit transports the dried sludge together with the coal to the solid fuel boiler by air current transport.
[8] The solid fuel boiler further comprises an input for additional fuel;
The sludge heat recovery apparatus according to any one of [1] to [7], wherein the additional fuel includes at least one of coal, plastic, paper, wood chips, and rubber.
[9] the solid fuel boiler further comprises a generator;
The sludge heat recovery apparatus according to any one of [1] to [8], wherein the power obtained from the generator is supplied to the transport section, or the sludge heat recovery apparatus further includes a sludge drying section and the power is supplied to the sludge drying section.
[10] A sludge heat recovery apparatus according to any one of [1] to [9], wherein the transport means for the dried sludge transported to the transport section is a vehicle, or the sludge heat recovery apparatus further comprises a sludge drying section, and the transport means for the sludge transported to the sludge drying section is a vehicle.
[11] A sludge heat recovery apparatus and a sewage treatment plant according to any one of [1] to [10],
A sludge heat recovery system in which dried sludge, which is sludge obtained at a sewage treatment plant, is transported to a transport section by a vehicle, or in which the sludge heat recovery device further includes a sludge drying section and the sludge obtained at the sewage treatment plant is transported to the sludge drying section by a vehicle.
[12] The sludge heat recovery apparatus according to any one of [1] to [10] or the sludge heat recovery system according to [10],
Equipped with a factory,
It is equipped with piping to supply steam obtained from the solid fuel boiler to the factory,
The factory is a paper mill that utilizes sludge heat.
[13] the solid fuel boiler further comprises a generator;
The sludge heat utilization factory according to [12], in which electricity obtained from the generator is supplied to the factory.

According to the present invention, it is possible to provide a sludge heat recovery device, a sludge heat recovery system, and a sludge heat utilization factory without installing a new heat recovery device or heat recovery system.

FIG. 1 is a schematic diagram showing an example of a sludge heat recovery system and a sludge heat utilization factory of the present invention, which are provided with a sludge heat recovery device according to a preferred embodiment of the present invention.

The present invention will be described in detail below. The following explanation of the constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower and upper limits.

[Sludge heat recovery equipment]
The sludge heat recovery apparatus of the present invention includes at least a transport section and a solid fuel boiler in this order, and the transport section transports at least dried sludge to the solid fuel boiler.
According to the present invention, it is possible to provide a sludge heat recovery device and a sludge heat utilization factory without installing a new heat recovery device or heat recovery system. In addition, it is possible to reduce the cost of transporting dried sludge and suppress odors and dust when transporting dried sludge.

For example, sewage treatment sludge or the like can be dried in a sludge drying section (so-called drying business, including carbonization) to produce dried sludge, and then the resulting dried sludge can be transported in a short time, thereby suppressing odors and dust and making it into solid fuel to be put into a boiler instead of being treated as industrial waste. For convenience, in this invention, fuel containing dried sludge and other materials transported to a solid fuel boiler may be referred to as solid fuel derived from dried sludge, or simply as solid fuel.
Specifically, by transporting the dried sludge to the solid fuel boiler through a transport unit integrated within the sludge heat recovery device, the transport cost can be significantly reduced and odors during transport can be suppressed.

In a preferred embodiment of the sludge heat recovery device of the present invention, the solid fuel derived from the dried sludge is directly transported to a solid fuel boiler, and the obtained steam or electricity (if the solid fuel boiler is equipped with a generator) is used in the sludge heat recovery device of the present invention or in a sludge fuel-utilizing factory. Therefore, the dried sludge can be used more effectively. In the conventional method and device for converting dried sludge into solid fuel, the number of businesses that have large-scale solid fuel boilers (biomass boilers, coal boilers, etc.) was limited, and the supply of the obtained solid fuel derived from the dried sludge sometimes exceeded the demand. In a preferred embodiment of the sludge heat recovery device of the present invention, since the solid fuel derived from the surplus dried sludge is not produced, there is no need to dispose of such solid fuel derived from the surplus dried sludge as industrial waste at a cost, and the cost of disposal can be reduced. In addition, the amount of waste to be disposed of in landfills can be reduced.
Furthermore, by using the sludge heat recovery device of the present invention, the dried sludge can be granulated, etc., to operate a solid fuel boiler as a solid fuel (certified as a valuable resource), so that the dried sludge is not disposed of as industrial waste, the solid fuel boiler can be operated efficiently, and _CO2 emissions can be reduced. In recent years, businesses are sometimes required to submit their own efforts to combat global warming and _CO2 emission reduction targets to public organizations as a "manifesto" (action declaration), and the sludge heat recovery device of the present invention is useful for formulating such a "manifesto."
Hereinafter, preferred embodiments of the sludge heat recovery apparatus of the present invention will be described.

<Configuration of sludge heat recovery device>
The overall configuration of the sludge heat recovery device will be described.
In the present invention, the sludge heat recovery apparatus includes at least a transport section and a solid fuel boiler in this order.
A preferred embodiment of the sludge heat recovery device will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of a sludge heat recovery system and a sludge heat utilization factory of the present invention, which are provided with a (preferred embodiment) sludge heat recovery device of the present invention.
In FIG. 1, the sludge heat recovery apparatus 101 includes an optional sludge drying section 11, a transport section 41, and a solid fuel boiler 51, in this order.
Dried sludge is obtained in a sludge drying section 11 which is provided as necessary.
The transport section 41 transports at least the dried sludge 22 to the solid fuel boiler 51 .
Each component of the sludge heat recovery apparatus of the present invention will be described in order.

<Sludge drying section>
The sludge drying section may be provided at least by, for example, a sewage treatment plant or a drying business operator. In the present invention, it is preferable that the sludge heat recovery device further includes a sludge drying section, and dried sludge is obtained in the sludge drying section. There are no particular limitations on the sludge supplied to the sludge drying section. Examples of the sludge include various organic sludges such as sewage sludge, paper sludge, building pit sludge, and food sludge. Among these, it is particularly preferable to use sewage sludge.
The sludge supplied to the sludge drying section is preferably dehydrated sludge that has been dehydrated to a certain extent. More preferably, in the sludge drying section 11, sludge 3 that has been dehydrated to a certain extent in a sludge dewatering machine 2 of the sewage treatment plant 1 is dried to obtain dried sludge 12.
The moisture content of the dewatered sludge is usually 70 to 85% by mass. The dewatered sludge is sometimes called a dewatered cake, and may be either solid or fluid. When the dewatered sludge has fluidity, the degree of fluidity is not particularly limited, but it is sufficient that the dewatered sludge can be sucked up by a suction vehicle, i.e., a vacuum car. It is preferable that the transport means for the dried sludge transported to the transport section in the present invention is a vehicle, or that the sludge heat recovery device further includes a sludge drying section, and the transport means for the sludge transported to the sludge drying section is a vehicle.

The drying performed in the sludge drying section may be a carbonization treatment or a simple drying treatment without carbonization. A simple drying treatment without carbonization is preferable.
The sludge drying section is not particularly limited, and may be a carbonization type sludge drying section or a steam type sludge drying section. A steam type sludge drying section is preferable. It is more preferable from the viewpoint of reducing _CO2 emissions that the sludge heat recovery device has a pipe that supplies (returns) steam obtained from the solid fuel boiler to the sludge drying section, and drying in the steam type sludge drying section is performed using the returned steam. In addition, heating may be performed using a fossil fuel such as heavy oil as an auxiliary. The drying temperature is preferably 100 to 300°C, more preferably 120 to 200°C, and particularly preferably 140 to 160°C.
From the viewpoint of reducing _CO2 emissions, it is preferable that the sludge heat recovery device has wiring that supplies electricity obtained from the generator to the sludge drying section, and that drying and transportation in the sludge drying section are performed using the returned electricity.

From the viewpoint of easy control of the net calorific value of the solid fuel, it is preferable that the moisture content of the dried sludge is 5 to 40% by mass. 20 to 40% by mass is more preferable. 25 to 35% by mass is even more preferable. The moisture content means the value obtained by keeping 50 g of the measurement object (e.g., dried sludge) in any dryer adjusted to 105°C for 20 hours and calculating the mass lost by this drying process as the moisture content.

<Transportation section>
In the present invention, the transport section transports at least the dried sludge to the solid fuel boiler.
It is preferable that the sludge heat recovery device has at least a transport unit and a solid fuel boiler integrated in this order, from the viewpoint of shortening the transport distance of the dried sludge, and reducing the transport cost and _CO2 emissions. It is preferable that one end of the transport unit is directly connected to the sludge drying unit. It is also preferable that the other end of the transport unit is directly connected to the solid fuel boiler.
The conveying means of the conveying section is not particularly limited, but examples thereof include a belt conveyor, a screw feeder, a wind conveyor (piping), a pump pressure conveyor, a road (vehicle), etc. For example, it is preferable to convey the solid fuel to the top of the solid fuel boiler by a conveyor. As the conveyor, it is preferable to use an RPF conveyor or a coal conveyor from the viewpoint of reducing costs by utilizing existing facilities.
The conveyor is preferably one that has been provided with corrosion protection against chlorine, etc. RPF conveyors are usually provided with corrosion protection against chlorine, etc., so that plastics containing polyvinyl chloride can be used. In contrast, coal conveyors often have insufficient corrosion protection against chlorine, etc. Therefore, it is preferable to use an RPF conveyor rather than a coal conveyor.
On the other hand, it is preferable that the conveying section and the solid fuel boiler, or the sludge drying section, the conveying section and the solid fuel boiler are located on the same premises, from the viewpoint of suppressing the processing cost. Also, it is preferable that the conveying section is not a public road, and it is more preferable that it is not a road. Therefore, it is preferable that the conveying means from the conveying section to the solid fuel boiler, or from the sludge drying section to the solid fuel boiler, is other than a vehicle, from the viewpoint of the conveying cost and the reduction of the _CO2 emissions.
However, the entire amount of dried sludge does not have to be transported to the solid fuel boiler via the transport unit. For example, a preferred embodiment is one in which a transport port leading to the outside of the sludge heat recovery device is provided between the sludge drying unit and the transport unit or in the transport unit, and part of the dried sludge is transported from the transport port to the outside of the sludge heat recovery device using a vehicle or the like and can be transferred to another facility or business.
From the viewpoint of reducing _CO2 emissions, it is preferable that the sludge heat recovery device has wiring that supplies power obtained from the generator to the transport section, and that transport in the transport section is performed using the returned power.

It is preferable that the transport section can be sealed between the transport section and the solid fuel boiler, and more preferably between the sludge drying section and the solid fuel boiler. By feeding the dried sludge into the solid fuel boiler in a sealed state, it is easier to suppress odors and dust when the dried sludge is transported.
The sealing means is not particularly limited, and examples thereof include a mode in which a cylindrical cover is provided to cover the transport section, and a mode in which the inside is made negative pressure to prevent odors and soot from scattering.

(RPF supply section)
It is preferable that the transport section 41 is equipped with an RPF input section so that the dried sludge 22 and the RPF 31 can be mixed in a desired ratio.
It is also preferable that the transport section 41 is provided with a coal input section so that the dried sludge 22 and coal (not shown) can be mixed in a desired ratio.
From the viewpoint of adjusting the dried sludge to easily satisfy Condition 1A, Condition 1B or Condition 1C in the preferred embodiment described later, it is more preferable that the conveying section conveys the RPF containing at least one of plastic, paper and paper sludge, or coal, and the dried sludge to the solid fuel boiler. Here, it is preferable that the conveying section conveys the dried sludge together with the coal to the solid fuel boiler by airflow conveyance. Specifically, it is preferable that the conveying section has a crushing means for the dried sludge, or further includes a sludge drying section, and the sludge drying section has a crushing means for the dried sludge. A crusher can be used as the crushing means. In addition, by conveying the dried sludge by airflow, the dried sludge can be crushed to a fine particle size. The average particle size of the dried sludge in the conveying section is not particularly limited, but is preferably 10 mm or less, more preferably 3 mm or less.

In a preferred embodiment of the present invention, when the total net calorific value of all fuels supplied to a solid fuel boiler is ^Q1 and the net calorific value of the dried sludge is ^Q2 , it is preferable that the dried sludge satisfies the following condition 1A, condition 1B or condition 1C. By adjusting the solid fuel containing dried sludge so as to satisfy these conditions, it is possible to obtain a high calorific value while adjusting the heat of vaporization when the moisture becomes steam and achieving the same degree of combustion as coal.
Condition 1A: The moisture content of the dried sludge is 20 mass % or less, and the value of 100%×Q ² /Q ¹ is 40% or less.
Condition 1B: The moisture content of the dried sludge is more than 20 mass % and not more than 30 mass %, and the value of 100%×Q ² /Q ¹ is not more than 20%.
Condition 1C: The moisture content of the dried sludge is more than 30 mass % and not more than 40 mass %, and the value of 100%×Q ² /Q ¹ is not more than 10%.
The calorific value can be measured using a combustion heat measuring device (manufactured by IKA, model "C5003").

RPF generally means high-calorie solid fuel made from waste plastics and waste paper, which are difficult to recycle, among industrial waste. RPF manufacturing raw materials mean raw materials mainly made from waste plastics and waste paper that can be used to manufacture such normal RPF, but also include RPF that has already been made into solid fuel. In addition, raw materials mainly made from plastics and/or paper (with a total content of plastics and paper of approximately 50% by mass or more) are included in RPF manufacturing raw materials.
There are no particular limitations on the type of plastic (including waste plastics; the same applies below) that may be contained in the raw materials for RPF production, but it is preferable to use plastics that do not produce toxic gases when burned. For example, it is preferable to use polystyrene, polyethylene, and polypropylene. It is also preferable to use chlorine-containing plastics such as polyvinyl chloride after taking measures against corrosion from chlorine, etc. In addition to plastics and paper (including waste paper; the same applies below), waste wood may be an example of materials that may be contained in the raw materials for RPF production.

Paper sludge is wastewater treatment sludge (dewatered sludge) from a paper mill. Before using the paper sludge as other materials, it may be concentrated in a settling tank or rotary screen and dewatered with a screw press or belt filter. Paper sludge includes mixed sludge in which all wastewater treatment sludge generated in a factory is mixed, sludge mainly composed of fibrous material recovered from pulp-based wastewater in a pressurized flotation device, simple settling tank, coagulation settling tank, fiber recovery device, etc. (DIP sludge), excess sludge generated in an activated sludge device, screen rejects, cleaner rejects, broke, coated broken, dry broken, or wet broken in the papermaking process. For example, fibrous material recovered from wastewater without being separated by a screen includes fibers less than 0.1 mm in length.
In the present invention, it is preferable to use raw materials for manufacturing RPF that contain at least one of plastic, paper, and paper sludge.

<Solid fuel boiler>
It is preferable that the conveying unit is connected to the upper part of the solid fuel boiler. For example, it is preferable that the conveying unit is connected to an area within 30% from the top of the height of the solid fuel boiler, more preferably within 20% from the top, and particularly preferably within 10% from the top.
The height of the solid fuel boiler is not particularly limited, and for example, the lower limit is preferably 10 m or more, more preferably 20 m or more, and particularly preferably 40 m or more, and the upper limit is preferably 100 m or less, more preferably 80 m or less, and particularly preferably 60 m or less.

The solid fuel boiler is not particularly limited, and examples thereof include a biomass boiler and a fossil fuel boiler (particularly a coal boiler). The solid fuel boiler is preferably a biomass boiler.
The combustion method of the solid fuel boiler is not particularly limited, and examples thereof include a fluidized bed furnace, a stoker furnace, a melting furnace, a rotary kiln, etc. Among these, a fluidized bed furnace is preferred from the viewpoint of maintenance. The fluidized bed furnace is more preferably a circulating fluidized bed furnace from the viewpoint of temperature control inside the furnace.
The solid fuel boiler may be a combination of two or more of these furnaces, in which case a fluidized bed furnace and a stoker furnace are preferably combined in this order.

(Additional fuel supply section)
Preferably, the solid fuel boiler 51 further comprises an input 52 for additional fuel.
The additional fuel 53 preferably includes at least one of coal, plastic, paper, wood chips, and rubber. The additional fuel 53 may include fiber waste and the like.
By feeding the solid fuel 22 containing dried sludge and other additional fuels 53 into the solid fuel boiler 51, a high amount of heat can be obtained.

(Pipes supplying steam)
The sludge heat recovery device preferably includes a pipe (not shown) for supplying (returning) the steam 55 obtained from the solid fuel boiler 51 to the sludge drying section 11. This configuration reduces the cost of obtaining the energy input for drying in the sludge drying section, improves energy efficiency, and reduces _CO2 emissions.
In addition, in the case where the solid fuel boiler is equipped with a generator, it is preferable that these pipes are arranged so that steam that has passed through the generator can be used.

(Generator)
The solid fuel boiler 51 preferably further includes a generator 56. The steam 55 generated in the solid fuel boiler 51 is preferably supplied to a turbine (not shown) of the generator 56 and used to generate electricity.
It is preferable that the sludge heat recovery device 101 supplies the electric power 57 obtained from the generator 56 to the transport section 41, or that the sludge heat recovery device 101 further includes a sludge drying section 11 and supplies the electric power to the sludge drying section 11. It is more preferable to supply the electric power to both the sludge drying section 11 and the transport section 41.
This configuration reduces the cost of obtaining the energy input for drying in the sludge drying section and the transport section, improves energy efficiency, and reduces _CO2 emissions.

<Other devices>
The sludge heat recovery device may include parts having other functions.
For example, it is usually preferable to have a deodorizing section to treat odors, a dust collection section to treat dust, a temperature reducing tower, a reaction tower, an ash pit, an exhaust section such as a chimney that can discharge exhaust air to the outside, a heat exchanger, a noise reduction device, a deodorizing agent sprayer, etc.

It is preferable that all of the facilities constituting the sludge heat recovery apparatus are located within the same administrative district.
By integrating the sewage treatment plant, drying business, and solid fuel boiler (with the equipment being connected and the owner and operator being the same), sewage treatment sludge can be used as fuel for the solid fuel boiler without ever being treated as industrial waste.

[Sludge heat recovery system]
The sludge heat recovery system of the present invention comprises the sludge heat recovery device of the present invention and a sewage treatment plant, and transports dried sludge consisting of sludge obtained at the sewage treatment plant to a transport section by a vehicle, or the sludge heat recovery device further comprises a sludge drying section, and the sludge obtained at the sewage treatment plant is transported to the sludge drying section by a vehicle.
1, a sludge fuel production system 102 includes a sludge fuel production device 101 and a sewage treatment plant 1. For example, sludge 3 obtained in a sludge dewatering machine 2 in the sewage treatment plant 1 is preferably transported to a sludge drying section 11 by a vehicle.
As the sewage treatment plant, a normal sewage treatment plant can be used.
The sludge dehydrator is not particularly limited, and any known device can be used, including a conventionally known centrifugal separator, an indirect heating type dryer, or a reduced pressure heating type dryer. Examples of the dehydrator include a screw press, a belt press, a belt filter, and a centrifuge.

In the sludge heat recovery system of the present invention, it is preferable that the sludge heat recovery device and the sewage treatment plant are located within the same administrative district.
In the case where a public entity has a sewage treatment plant, a preferred embodiment is for an operator (e.g., an operator that owns a factory such as a paper mill or a power plant) to lease land for the solid fuel boiler portion to the public entity (e.g., a local government such as the nation, a prefecture, or a city, town, or village) that owns the sewage treatment plant, and install the sludge heat recovery apparatus of the present invention on that land (install a sludge drying unit and a conveying unit).
The sludge heat recovery system of the present invention efficiently links the sludge heat recovery device and the sewage treatment plant, and can efficiently recycle sludge as fuel. In addition, because sludge can be easily treated in a short time, the problem of odor generation due to decay can be suppressed. Furthermore, the heat generated by combustion in the solid fuel boiler can be used, for example, in other facilities that require heating.
Other facilities requiring such heating include factories (preferably paper mills), power plants, greenhouses for growing flowers and the like, and the like.
It is preferable for other facilities that require heating to be located close to the sludge heat recovery equipment in order to reduce the costs of using electricity and steam.

[Sludge heat utilization factory]
The sludge heat utilization factory of the present invention comprises the sludge heat recovery device of the present invention or the sludge heat recovery system of the present invention, and a factory, and is equipped with piping for supplying steam obtained from a solid fuel boiler to the factory, and the factory is a paper factory.
1, the sludge heat utilization factory 103 includes a sludge heat recovery system 102 (including a sludge heat recovery device 101) and a factory 61. For example, the factory 61 is preferably a paper factory, and includes piping (not shown) for supplying steam 55 obtained from a solid fuel boiler 51 to the factory 61.
In the sludge heat utilization factory 103 , the solid fuel boiler 51 is preferably further equipped with a generator 56 , and electricity 57 obtained from the generator 56 is preferably supplied to the factory 61 .

By integrating (connecting) the sewage treatment plant, sludge drying section, transport section, solid fuel boiler and factory, it is possible to contribute to the efficient use of thermal energy.

1 Sewage treatment plant 2 Sludge dewatering machine 3 Sludge 11 Sludge drying section 12 Dried sludge 22 Solid fuel derived from dried sludge 31 RPF, coal 41 Transport section 51 Solid fuel boiler 52 Additional fuel input section 53 Additional fuel 55 Steam 56 Generator 57 Electricity 61 Factory 101 Sludge heat recovery device 102 Sludge heat recovery system 103 Sludge heat utilization factory

Claims (8)

At least a sludge drying section, a conveying section, and a solid fuel boiler are provided in this order;
A sludge heat recovery apparatus, comprising: a sludge drying unit that obtains dried sludge; and a transport unit that transports at least the dried sludge to the solid fuel boiler,
One end of the conveying section is directly connected to the sludge drying section, and the other end is directly connected to the solid fuel boiler,
a sealing means capable of sealing the space between the sludge drying section and the solid fuel boiler;
The transport unit has a crushing means for crushing the dried sludge,
The inside of the conveying section is under negative pressure,
The transport unit transports the dried sludge together with the coal to the solid fuel boiler by air current transport . The sludge heat recovery device according to claim 1, wherein the moisture content of the dried sludge is 5 to 40% by mass. The sludge heat recovery apparatus according to claim 1 or 2, wherein the transport section transports RPF containing at least one of plastic , paper, and paper sludge, the coal, and the dried sludge to the solid fuel boiler. the solid fuel boiler further comprises an input for additional fuel;
The sludge heat recovery apparatus according to any one of claims 1 to 3 , wherein the additional fuel includes at least one of coal, plastic, paper, wood chips, and rubber. the solid fuel boiler further comprises a generator;
The sludge heat recovery apparatus according to any one of claims 1 to 4 , wherein electric power obtained from said generator is supplied to said transport section or to said sludge drying section. A sludge heat recovery apparatus and a sewage treatment plant according to any one of claims 1 to 5 ,
A sludge heat recovery system in which sludge obtained at the sewage treatment plant is transported to the sludge drying section by a vehicle. The sludge heat recovery apparatus according to any one of claims 1 to 5 or the sludge heat recovery system according to claim 6 ,
Equipped with a factory,
a piping for supplying steam obtained from the solid fuel boiler to the factory;
The factory is a paper factory, and uses sludge heat. the solid fuel boiler further comprises a generator;
The sludge heat utilization factory according to claim 7 , wherein the power obtained from the generator is supplied to the factory.

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