CN115335494A

CN115335494A - Solid fuel production system, solid fuel production method, and solid fuel

Info

Publication number: CN115335494A
Application number: CN202180022938.1A
Authority: CN
Inventors: 石川真也; 本田英信; 杤本信彦; 长谷川克久
Original assignee: Daqi Aikexi Water Sustainable New Energy Co ltd; Northeast Power Generation Industry Co ltd
Current assignee: Daqi Aikexi Water Sustainable New Energy Co ltd; Northeast Power Generation Industry Co ltd
Priority date: 2020-04-27
Filing date: 2021-04-23
Publication date: 2022-11-11
Anticipated expiration: 2041-04-23
Also published as: JP2021175781A; CN115335494B; JP6827582B1; KR20220140854A; JP2021175788A; WO2021220958A1; JP6994590B2

Abstract

A solid fuel production system (1) produces solid fuel from a raw material containing waste plastic. A solid fuel production system (1) is provided with a hydrothermal reaction device (10), a cleaning device (20), and separation devices (30, 40). The hydrothermal reaction device (10) comprises: a reaction chamber which decomposes a raw material into fine particles by a hydrothermal reaction; a dispersion liquid supply unit for supplying the dispersion liquid to the reaction chamber after the decomposition; and a suspension discharge unit that discharges a suspension in which fine particles are dispersed in the supplied dispersion liquid. A cleaning device (20) cleans the particles by agitating the discharged suspension. The separation devices (30, 40) separate particles from the suspension to produce a solid fuel.

Description

Solid fuel production system, solid fuel production method, and solid fuel

Technical Field

The present invention relates to a solid fuel production system, a solid fuel production method, and a solid fuel.

Background

A solid fuel production system for producing a solid fuel from a raw material containing waste plastics is known. For example, a solid fuel production system described in patent document 1 includes a reaction chamber for decomposing organic waste containing polyvinyl chloride by hydrothermal reaction. The solid fuel production system reduces the chlorine concentration of the solid component by supplying the decomposed solid component to the mixing/stirring tank and supplying water to the mixing/stirring tank, and mixing and stirring the solid component in the mixing/stirring tank.

Documents of the prior art

Patent literature

Patent document 1: japanese patent application laid-open No. 2010-37536

Disclosure of Invention

Problems to be solved by the invention

However, the chlorine concentration of coal is quite low. Therefore, for example, in a coal boiler used in thermal power generation, when a solid fuel is used instead of a part of coal, if the chlorine concentration of the solid fuel is not sufficiently reduced, there is a possibility that a member contacted by combustion gas or combustion ash may be corroded. However, the above solid fuel production system has a problem that the chlorine concentration of the solid fuel cannot be sufficiently reduced.

One of the objects of the present invention is to reduce the chlorine concentration of solid fuel.

Means for solving the problems

In one aspect, a solid fuel manufacturing system manufactures solid fuel from a feedstock comprising waste plastic.

The solid fuel production system is provided with a hydrothermal reaction device, a cleaning device, and a separation device.

The hydrothermal reaction device comprises: a reaction chamber that decomposes a raw material into fine particles by a hydrothermal reaction; a dispersion liquid supply unit for supplying the dispersion liquid to the reaction chamber after decomposition; and a suspension discharge unit that discharges a suspension in which fine particles are dispersed in the supplied dispersion liquid. The cleaning device cleans the microparticles by stirring the discharged suspension. The separation device generates solid fuel by separating particulates from a suspension.

In another aspect, a solid fuel manufacturing method manufactures a solid fuel from a feedstock comprising waste plastic.

The solid fuel manufacturing method includes:

decomposing the raw material into fine particles by hydrothermal reaction in the reaction chamber;

after decomposing the raw materials, introducing the dispersion into the reaction chamber;

discharging a suspension in which the fine particles are dispersed in the introduced dispersion liquid from the reaction chamber;

washing the microparticles by agitating the discharged suspension;

the solid fuel is produced by separating the particles from the suspension.

In another aspect, a solid fuel is produced by decomposing a raw material containing waste plastic into fine particles by a hydrothermal reaction and washing the fine particles.

In the solid fuel, the average particle diameter of the solid fuel is less than 1180 [ mu ] m, and the chlorine concentration of the solid fuel is 0.30 wt% or less.

Effects of the invention

The chlorine concentration of the solid fuel can be reduced.

Drawings

Fig. 1 is a block diagram showing the configuration of a solid fuel production system according to a first embodiment.

Fig. 2 is an explanatory view showing the configuration of the hydrothermal reaction apparatus and the cleaning apparatus according to the first embodiment.

Fig. 3 is a flowchart showing the method for producing a solid fuel according to the first embodiment.

Fig. 4 is a block diagram showing the configuration of a solid fuel production system according to a first modification of the first embodiment.

Fig. 5 is a block diagram showing the configuration of a solid fuel production system according to a second modification of the first embodiment.

Fig. 6 is a graph showing an example of changes in the chlorine concentration of the solid fuel with respect to the particle diameter and the presence or absence of purging.

Fig. 7 is a block diagram showing the configuration of a solid fuel production system according to a second embodiment.

Fig. 8 is a block diagram showing the configuration of a solid fuel production system according to a third embodiment.

Fig. 9 is a block diagram showing the configuration of a solid fuel production system according to the fourth embodiment.

Fig. 10 is a block diagram showing the configuration of a solid fuel production system according to a fifth embodiment.

Detailed Description

Hereinafter, embodiments of a solid fuel production system, a solid fuel production method, and a solid fuel according to the present invention will be described with reference to fig. 1 to 10.

< first embodiment >

(summary)

The solid fuel production system of the first embodiment produces solid fuel from a raw material containing waste plastic.

The hydrothermal reaction device comprises: a reaction chamber which decomposes a raw material into fine particles by a hydrothermal reaction; a dispersion liquid supply unit for supplying the dispersion liquid to the reaction chamber after the decomposition; and a suspension discharge unit that discharges a suspension in which fine particles are dispersed in the supplied dispersion liquid. The cleaning device cleans the microparticles by stirring the discharged suspension. The separation device generates the solid fuel by separating the particles from the suspension.

However, fine particles generated by the hydrothermal reaction may aggregate to form aggregates. The aggregate is not easily decomposed even when stirred together with the dispersion liquid. Further, the chlorine-containing substances that have entered the interior of the aggregate are less likely to elute out even when stirred together with the dispersion liquid. The chlorine-containing substance is a substance containing a chlorine atom. Therefore, for example, as in the solid fuel production system described in patent document 1, when the dispersion is not supplied to the reaction chamber after decomposition by the hydrothermal reaction and the solid component is discharged from the reaction chamber, there is a possibility that the chlorine concentration of the produced solid fuel cannot be sufficiently reduced.

In contrast, according to the solid fuel production system of the first embodiment, the hydrothermal reaction device includes: a dispersion liquid supply unit for supplying the dispersion liquid to the reaction chamber after the decomposition; and a suspension discharge unit that discharges a suspension in which fine particles are dispersed in the dispersion liquid. This can suppress aggregation of fine particles generated by the hydrothermal reaction. As a result, the chlorine concentration of the fine particles can be reduced by the cleaning in the cleaning device, and therefore the chlorine concentration of the solid fuel can be reduced.

Next, the solid fuel production system according to the first embodiment will be described in more detail.

(constitution)

As shown in fig. 1, a solid fuel manufacturing system 1 manufactures solid fuel from a raw material containing waste plastic. In this example, the raw materials are composed of a first raw material and a second raw material.

In this example, the first feedstock is waste plastic. Waste plastics are waste products containing plastics. For example, waste plastics include containers for packaging goods. In this example, the waste plastics contained chlorine-containing substances such as salt and polyvinyl chloride that adhered to the container.

In this example, the second feedstock is biomass. For example, the biomass is waste paper, sludge, grass, straw, wheat straw, rice hulls, or woody biomass (e.g., flowing wood, thinning wood, or wood waste, etc.), and the like. For example, the wood waste is bark or sawdust generated in the production of wood, wood chips, a disintegrated material of a building, prunes, or the like.

The solid fuel production system 1 includes a hydrothermal reaction device 10, a first raw material supply unit 11, a second raw material supply unit 12, a steam supply unit 13, a water supply unit 14, a hydroxide supply unit 15, a steam recovery unit 16, a cleaning device 20, a large-diameter fine particle supply unit 25, a dehydration device 30, a drying device 40, a separation liquid storage unit 51, and a drainage treatment device 52.

As shown in fig. 2, the hydrothermal reaction apparatus 10 includes a reaction chamber 101, a stirrer 102, a motor 103, a first raw material introduction part 104, a second raw material introduction part 105, a steam introduction part 106, a water introduction part 107, a hydroxide introduction part 108, a steam discharge part 109, and a suspension discharge part 110.

The reaction chamber 101 is a space provided inside the hydrothermal reaction apparatus 10. In this example, the reaction chamber 101 is cylindrical and extends in a predetermined extending direction. The reaction chamber 101 holds water having a predetermined pressure and a predetermined temperature. In this example, the reaction chamber 101 holds water in a subcritical state (in other words, subcritical water). For example, the pressure of subcritical water held in reaction chamber 101 is a pressure of 1.5MPa to 3.5 MPa. For example, the temperature of subcritical water held in the reaction chamber 101 is a temperature of 180 ℃ to 250 ℃.

In this example, the reaction chamber 101 maintains subcritical water for a predetermined time, thereby decomposing the raw material into fine particles by hydrothermal reaction. For example, the reaction chamber 101 holds subcritical water for a time of 1 minute to 60 minutes.

The stirring body 102 includes a plurality of stirring blades. The number of the stirring blades provided in the stirrer 102 may be 1. For example, the stirring blade is a propeller blade, a turbine blade, a paddle blade, an anchor blade, a helical ribbon blade, or the like. The hydrothermal reaction apparatus 10 may further include baffles on the inner wall of the reaction chamber 101.

The stirring member 102 is rotatably supported in the reaction chamber 101 so that a central axis of rotation extends in the extending direction. The stirring body 102 is rotationally driven by a motor 103. With this configuration, the stirrer 102 stirs the substance introduced into the reaction chamber 101.

In this example, the stirring body 102 is rotationally driven in the first rotational direction, whereby the substance introduced into the reaction chamber 101 is moved so as to approach the center of the reaction chamber 101 in the extending direction. On the other hand, the stirring body 102 is rotationally driven in a second rotational direction opposite to the first rotational direction, whereby the substance introduced into the reaction chamber 101 moves so as to approach the end of the reaction chamber 101 in the extending direction. For example, the rotation direction of the stirring body 102 is changed every time a predetermined time elapses.

The first raw material introducing unit 104 introduces the first raw material supplied from the first raw material supplying unit 11 into the reaction chamber 101. The first raw material introduction portion 104 adjusts the amount of the first raw material introduced into the reaction chamber 101. The number of the first raw material introduction parts 104 included in the hydrothermal reaction device 10 may be 2 or more.

The second raw material introducing part 105 introduces the second raw material supplied from the second raw material supplying part 12 into the reaction chamber 101. The second raw material introduction portion 105 adjusts the amount of the second raw material introduced into the reaction chamber 101. The number of the second raw material introduction portions 105 provided in the hydrothermal reaction apparatus 10 may be 2 or more.

The hydrothermal reaction apparatus 10 may include a raw material introducing unit that introduces a raw material composed of the first raw material and the second raw material into the reaction chamber 101, instead of the first raw material introducing unit 104 and the second raw material introducing unit 105.

The steam introduction unit 106 introduces the steam supplied from the steam supply unit 13 into the reaction chamber 101. The steam introducing unit 106 adjusts the amount of steam introduced into the reaction chamber 101. In this example, the steam supply unit 13 supplies steam. The steam supplied from the steam supply unit 13 may be steam of an aqueous solution (for example, an aqueous solution of hydroxide supplied from the hydroxide supply unit 15). The number of the steam introduction parts 106 provided in the hydrothermal reaction apparatus 10 may be 2 or more.

The water inlet 107 introduces the water supplied from the water supply 14 into the reaction chamber 101. The water inlet 107 adjusts the amount of water introduced into the reaction chamber 101. In this example, the water introduced into the reaction chamber 101 through the water introduction unit 107 corresponds to the dispersion liquid introduced into the reaction chamber 101 after the decomposition of the raw material by the hydrothermal reaction. The dispersion liquid may be an aqueous solution of a hydroxide supplied from the hydroxide supply unit 15. The number of the water introduction parts 107 provided in the hydrothermal reaction apparatus 10 may be 2 or more.

The hydroxide introduction unit 108 introduces the hydroxide supplied from the hydroxide supply unit 15 into the reaction chamber 101. The hydroxide introduction section 108 adjusts the amount of hydroxide introduced into the reaction chamber 101. For example, the hydroxide is calcium hydroxide.

In this example, a hydrothermal reaction is generated after the hydroxide is introduced into the reaction chamber 101. In the hydrothermal reaction, the raw material is decomposed into fine particles. At this time, it is presumed that the chlorine contained in the polyvinyl chloride is substituted with the hydroxyl group by the hydroxide ion generated from the hydroxide reacting with the polyvinyl chloride contained in the waste plastic.

It is also presumed that calcium chloride is produced by the reaction of the chloride ions produced by this reaction with the calcium ions produced from the hydroxide. Further, it is presumed that the generated calcium chloride is present in a mixture in the fine particles generated by the hydrothermal reaction. As described later, the calcium chloride mixed in the particulates is removed by the washing in the washing apparatus 20. Thus, the chlorine concentration of the fine particles after washing can be sufficiently reduced.

The hydroxide may be a hydroxide of a metal other than calcium (e.g., aluminum, nickel, iron, magnesium, zinc, copper, sodium, or the like). In addition, the solid fuel production system 1 may use ammonia instead of the hydroxide. The number of the hydroxide introduction parts 108 included in the hydrothermal reaction apparatus 10 may be 2 or more.

The steam discharge unit 109 discharges the steam in the reaction chamber 101 to the steam recovery unit 16 after the decomposition of the raw material by the hydrothermal reaction. It is presumed that the steam contains a chlorine-containing substance. The steam discharge unit 109 includes a valve for opening and closing a passage that communicates the reaction chamber 101 and the steam recovery unit 16. The number of the steam discharge units 109 provided in the hydrothermal reaction device 10 may be 2 or more.

The vapor recovery unit 16 includes a water storage tank for storing water. The steam recovery unit 16 introduces steam discharged from the reaction chamber 101 into water stored in the water storage tank. As shown in fig. 1, the steam recovery unit 16 supplies recovered water, which is water stored in the water storage tank, to the wastewater treatment apparatus 52.

As shown in fig. 2, the suspension discharger 110 discharges the suspension in the reaction chamber 101 to the outside of the hydrothermal reaction apparatus 10. In this example, the fine particles generated by the hydrothermal reaction in the reaction chamber 101 are dispersed in the dispersion liquid (water in this example) introduced from the water introduction part 107.

The suspension discharge unit 110 includes a valve for opening and closing a passage that communicates the reaction chamber 101 with the outside of the hydrothermal reaction apparatus 10. The number of the suspension discharge units 110 provided in the hydrothermal reaction apparatus 10 may be 2 or more.

As shown in fig. 1, the cleaning device 20 includes a first cleaning unit 21, a large-diameter particulate removal unit 22, a steam cleaning unit 23, and a second cleaning unit 24.

As shown in fig. 2, the first cleaning unit 21 includes a cleaning tank 211, an agitator 212, and a suspension discharge unit 213.

The cleaning tank 211 stores the suspension discharged from the suspension discharge unit 110 of the hydrothermal reaction apparatus 10.

The stirring body 212 includes a stirring blade. The number of the stirring blades provided in the stirrer 212 may be 2 or more. For example, the stirring blade is a propeller blade, a turbine blade, a paddle blade, an anchor blade, a helical ribbon blade, or the like. First cleaning unit 21 may have a baffle plate on the inner wall of cleaning tank 211.

The stirring body 212 is rotatably supported inside the cleaning tank 211 and is driven to rotate by a motor, not shown. With such a configuration, the stirring body 212 stirs the substance (suspension in this example) introduced into the washing tank 211.

In addition, first cleaning unit 21 may introduce water supplied from water supply unit 14 into cleaning tank 211. In addition, the first cleaning unit 21 may introduce the hydroxide supplied from the hydroxide supply unit 15 into the cleaning bath 211.

In this example, first cleaning unit 21 includes a heater, not shown, and heats the substance introduced into cleaning tank 211 by heat generated by the heater. For example, first cleaning unit 21 maintains the temperature of the substance introduced into cleaning tank 211 at a predetermined temperature. For example, the temperature maintained by the first cleaning portion 21 is a temperature of 40 ℃ to 90 ℃.

With such a configuration, the first cleaning portion 21 cleans the fine particles by heating and stirring the suspension discharged from the reaction chamber 101. The first cleaning unit 21 may be configured to clean the fine particles by stirring the suspension without heating the suspension.

The suspension discharge unit 213 discharges the suspension in the cleaning tank 211 to the outside of the first cleaning unit 21. The suspension discharge unit 213 includes a valve for opening and closing a passage that communicates between the inside of the cleaning tank 211 and the outside of the first cleaning unit 21.

The large-diameter microparticle-removing section 22 includes a classifying body 221. The suspension discharged from the suspension discharge unit 213 is supplied to the classifier 221. The classifier 221 captures large-diameter microparticles, which are microparticles having a particle diameter larger than a predetermined reference particle diameter, among microparticles contained in the supplied suspension, and allows portions other than the large-diameter microparticles in the supplied suspension to pass therethrough. In this example, the reference particle diameter was 0.2mm. The reference particle size may be 0.1mm to 5mm in length.

In this example, the classification body 221 is a wedge wire screen. In this example, the interval between the wedge wires adjacent to each other is approximately equal to the reference particle diameter. The classifying body 221 may be a wire mesh other than a wedge wire mesh, a metal or resin mesh, a perforated metal mesh, or a porous body. The large-diameter fine particle removing unit 22 may be realized by a solid-liquid separator such as Slit Saver.

With such a configuration, the large-diameter particle removing unit 22 removes large-diameter particles from the particles cleaned by the first cleaning unit 21.

The large-diameter fine particle removing unit 22 supplies the large-diameter fine particles captured by the classifying body 221 to the large-diameter fine particle supplying unit 25. Further, the large-diameter microparticle removal unit 22 supplies the suspension that has passed through the classifying body 221 to the steam cleaning unit 23.

The steam cleaning unit 23 includes a solid-liquid separator 231. The suspension having passed through the classifying body 221 is supplied to the solid-liquid separator 231. The solid-liquid separator 231 captures fine particles contained in the supplied suspension and allows a portion other than the fine particles in the supplied suspension (in other words, the separation liquid) to pass therethrough.

In this example, the solid-liquid separator 231 is a wedge wire screen. The interval between wedge-shaped filaments adjacent to each other is shorter than the reference particle diameter. In this example, the spacing between wedge wires adjacent to each other is 20 μm. In addition, the interval between wedge wires adjacent to each other may also be 1 μm to 100 μm in length. The solid-liquid separator 231 may be a wire mesh other than a wedge wire mesh, a metal or resin mesh, a punched metal mesh, or a porous body.

The steam cleaning unit 23 cleans the microparticles captured by the solid-liquid separator 231 with steam by blowing the steam supplied from the steam supply unit 13 to the microparticles.

The steam cleaning unit 23 supplies the fine particles captured by the solid-liquid separator 231 and cleaned with steam to the second cleaning unit 24. Further, the steam cleaning unit 23 supplies the separated liquid having passed through the solid-liquid separator 231 to the separated liquid storage unit 51.

The second cleaning unit 24 includes a cleaning tank 241 and a stirring body 242.

As shown in fig. 1 and 2, the cleaning tank 241 stores water supplied from the water supply unit 14. In this example, the water stored in the cleaning tank 241 may be referred to as a cleaning liquid. The cleaning liquid may be an aqueous solution of hydroxide supplied from the hydroxide supply unit 15. The steam cleaning section 23 supplies the cleaning tank 241 with the fine particles. With such a configuration, the cleaning tank 241 stores a suspension in which the fine particles cleaned by the steam cleaning unit 23 are dispersed in the water supplied from the water supply unit 14.

The stirring body 242 includes a stirring blade. The number of the stirring blades provided in the stirring body 242 may be 2 or more. For example, the stirring blade is a propeller blade, a turbine blade, a paddle blade, an anchor blade, a helical ribbon blade, or the like. The second cleaning section 24 may include a baffle on the inner wall of the cleaning tank 241.

Stirring body 242 is rotatably supported inside cleaning tub 241, and is driven and rotated by a motor, not shown. With such a configuration, the stirring body 242 stirs the substance (suspension in this example) stored in the cleaning tank 241.

In this example, the second cleaning section 24 includes a heater, not shown, and heats the substance introduced into the cleaning tank 241 by heat generated by the heater. For example, the second cleaning portion 24 maintains the temperature of the substance introduced into the cleaning tank 241 at a predetermined temperature. For example, the temperature maintained by the second cleaning portion 24 is a temperature of 40 ℃ to 90 ℃.

With such a configuration, the second cleaning unit 24 cleans the fine particles by heating and stirring the suspension in which the fine particles cleaned by the steam cleaning unit 23 are dispersed in water. The second cleaning unit 24 may be configured to clean the fine particles by stirring the suspension without heating the suspension.

As shown in fig. 1, the second cleaning unit 24 supplies the dewatering device 30 with a suspension in which the cleaned fine particles are dispersed.

The large-diameter fine particle supply unit 25 supplies the large-diameter fine particles removed by the large-diameter fine particle removal unit 22 to the reaction chamber 101. In this example, the large-diameter fine particle supply unit 25 supplies the large-diameter fine particles to the reaction chamber 101 through the first raw material introduction unit 104. The hydrothermal reaction apparatus 10 may further include a large-diameter fine particle introduction unit for introducing large-diameter fine particles into the reaction chamber 101, in addition to the first raw material introduction unit 104.

The dewatering device 30 dewaters the suspension supplied from the second cleaning unit 24 to separate the separated liquid from the suspension. In this example, the dewatering device 30 is a filter press type dewatering device. The dehydration device 30 may be a type other than a filter press type (for example, a screw filter press type, a belt filter press type, a centrifugal separation type, or the like).

The dewatering device 30 supplies the dewatered cake after dewatering to the drying device 40. Further, the dehydration device 30 supplies the separated separation liquid to the separation liquid reservoir 51.

The drying device 40 dries the dehydrated cake supplied from the dehydration device 30 to produce a solid fuel. In this example, the solid fuel produced by the drying device 40 is in the form of fine powder or particles.

As described above, in the present embodiment, the dehydration device 30 and the drying device 40 constitute a separation device for separating fine particles from the suspension washed by the washing device 20 to generate the solid fuel.

As shown in fig. 1 and 2, the separated liquid storage unit 51 includes a storage tank 511 that stores the separated liquid supplied from the steam cleaning unit 23 and the separated liquid supplied from the dehydration device 30. The separated liquid reservoir 51 supplies the stored separated liquid to the wastewater treatment apparatus 52.

The wastewater treatment device 52 performs a treatment (in other words, a cleaning treatment) for cleaning the separation liquid supplied from the separation liquid reservoir 51 and the collected water supplied from the steam collection unit 16. In this example, the cleaning treatment includes a treatment for removing chlorine-containing substances contained in the separation liquid and the reclaimed water.

The solid fuel production system 1 may include a forming device for forming the dehydrated cake into a predetermined shape (for example, a rod shape) and the formed dehydrated cake may be dried by the drying device 40.

The solid fuel production system 1 may further include a molding device for molding the dried solid fuel into a predetermined shape (for example, a rod shape).

(action)

Next, the operation of the solid fuel production system 1 will be described with reference to fig. 3.

First, in the hydrothermal reaction apparatus 10, the first raw material introduction unit 104 introduces the first raw material supplied from the first raw material supply unit 11 into the reaction chamber 101, and the second raw material introduction unit 105 introduces the second raw material supplied from the second raw material supply unit 12 into the reaction chamber 101. Thus, the raw material is supplied to the reaction chamber 101 of the hydrothermal reaction apparatus 10 (step S101).

Next, in the hydrothermal reaction apparatus 10, the steam introducing part 106 introduces the steam supplied from the steam supplying part 13 into the reaction chamber 101, the water introducing part 107 introduces the water supplied from the water supplying part 14 into the reaction chamber 101, and the hydroxide introducing part 108 introduces the hydroxide supplied from the hydroxide supplying part 15 into the reaction chamber 101. Thus, steam, water, and hydroxide are supplied to the reaction chamber 101 of the hydrothermal reaction device 10 (step S102).

Next, in hydrothermal reaction apparatus 10, stirring body 102 is rotationally driven, and thus, while the substance introduced into reaction chamber 101 is stirred, water having a predetermined pressure and a predetermined temperature (in this example, subcritical water) is maintained in reaction chamber 101 for a predetermined period of time, whereby the raw material is decomposed into fine particles by hydrothermal reaction (step S103).

Next, in the hydrothermal reaction apparatus 10, the steam discharge unit 109 discharges the steam in the reaction chamber 101 to the steam recovery unit 16, and the water introduction unit 107 introduces the dispersion liquid (water in this example) supplied from the water supply unit 14 to the reaction chamber 101. In this way, steam is discharged from the reaction chamber 101 of the hydrothermal reaction device 10, and the dispersion liquid is supplied to the reaction chamber 101 (step S104). As a result, in the reaction chamber 101, the fine particles generated by the hydrothermal reaction are not dried, and a suspension in which the fine particles generated by the hydrothermal reaction are dispersed in a dispersion liquid (water in this example) is generated.

Next, in the hydrothermal reaction apparatus 10, the suspension discharge unit 110 discharges the suspension in the reaction chamber 101 to the outside of the hydrothermal reaction apparatus 10, thereby supplying the suspension to the cleaning tank 211 of the first cleaning unit 21 (step S105). In this case, in the present example, the stirrer 102 of the hydrothermal reaction device 10 is rotationally driven in the first rotational direction. Thereby, the suspension in the reaction chamber 101 is moved so as to be close to the suspension discharge portion 110.

Next, the cleaning device 20 heats and stirs the suspension supplied from the reaction chamber 101 in the cleaning tank 211 by the first cleaning unit 21 to clean the particles (step S106). Next, the cleaning apparatus 20 discharges the suspension in the cleaning tank 211 to the outside of the first cleaning unit 21 by the first cleaning unit 21, and supplies the suspension to the large-diameter microparticle removal unit 22.

Next, in the cleaning apparatus 20, the large-diameter particle removing unit 22 removes the large-diameter particles from the suspension by capturing the large-diameter particles in the supplied suspension with the classifying body 221 (step S107).

Next, the large-diameter particle removing unit 22 of the cleaning apparatus 20 supplies the removed large-diameter particles to the large-diameter particle supplying unit 25. In this example, the large-diameter fine particle supply unit 25 supplies the large-diameter fine particles supplied from the large-diameter fine particle removal unit 22 to the reaction chamber 101 when the raw material is next supplied to the reaction chamber 101.

Further, the large-diameter fine particle removing unit 22 of the cleaning apparatus 20 supplies the suspension having passed through the classifying body 221 to the steam cleaning unit 23.

Next, the steam cleaning unit 23 of the cleaning device 20 captures fine particles contained in the supplied suspension by the solid-liquid separator 231, thereby separating the fine particles and the separation liquid from the suspension. Further, in the cleaning device 20, the steam cleaning unit 23 sprays steam to the fine particles captured by the solid-liquid separator 231, thereby cleaning the fine particles with the steam (step S108).

Next, in the cleaning device 20, the steam cleaning unit 23 supplies the fine particles captured by the solid-liquid separator 231 and cleaned with steam to the second cleaning unit 24. Further, the steam cleaning unit 23 of the cleaning device 20 supplies the separated liquid having passed through the solid-liquid separator 231 to the separated liquid storage unit 51.

Next, in the cleaning apparatus 20, the second cleaning section 24 generates a suspension by dispersing the fine particles supplied from the steam cleaning section 23 in the cleaning liquid stored in the cleaning tank 241, and the fine particles are cleaned by heating and stirring the generated suspension in the cleaning tank 241 (step S109).

Next, the second cleaning unit 24 of the cleaning device 20 supplies the suspension in which the cleaned fine particles are dispersed in the cleaning liquid to the dehydration device 30.

Next, the dewatering device 30 dewaters the suspension supplied from the second cleaning portion 24, thereby separating the separation liquid and the dewatered cake from the suspension. Thereby, the dewatering device 30 generates a dewatered cake (step S110).

Next, the dewatering device 30 supplies the produced dewatered cake to the drying device 40, and supplies the separated liquid to the separated liquid reservoir 51.

Next, the drying device 40 dries the dehydrated cake supplied from the dehydrating device 30 to generate a solid fuel (step S111).

The storage tank 511 of the separated liquid storage unit 51 stores the separated liquid supplied from the steam cleaning unit 23 and the separated liquid supplied from the dewatering device 30, and supplies the stored separated liquid to the drain treatment device 52. Next, the wastewater treatment device 52 cleans the separation liquid supplied from the separation liquid reservoir 51 and the collected water supplied from the steam collection unit 16.

In this way, the solid fuel production system 1 produces solid fuel from a raw material containing waste plastic. The solid fuel production system 1 may repeatedly execute the above-described operations.

As described above, the solid fuel production system 1 of the first embodiment produces solid fuel from raw materials including waste plastics. The solid fuel production system 1 includes a hydrothermal reaction device 10, a cleaning device 20, and a separation device (in this example, a dehydration device 30 and a drying device 40).

The hydrothermal reaction apparatus 10 includes a reaction chamber 101, a dispersion liquid introduction unit (in this example, a water introduction unit 107), and a suspension discharge unit 110. The reaction chamber 101 decomposes the raw material into fine particles by hydrothermal reaction. The dispersion liquid introducing section introduces the dispersion liquid (water in this example) into the reaction chamber 101 after decomposition. The suspension discharge unit 110 discharges a suspension in which fine particles are dispersed in the introduced dispersion liquid. The cleaning device 20 cleans the microparticles by stirring the discharged suspension. The separation device generates the solid fuel by separating the particles from the suspension.

However, the fine particles generated by the hydrothermal reaction may aggregate to form aggregates. The aggregate is not easily decomposed even when stirred together with the dispersion liquid. Further, the chlorine-containing substances that have entered the interior of the aggregate are less likely to elute out even when stirred together with the dispersion liquid. Therefore, as in the solid fuel production system described in patent document 1, when the solid component is discharged from the reaction chamber without introducing the dispersion into the reaction chamber after the decomposition by the hydrothermal reaction, there is a possibility that the chlorine concentration of the produced solid fuel cannot be sufficiently reduced.

In contrast, according to the solid fuel production system 1, the hydrothermal reaction apparatus 10 includes a dispersion liquid introduction portion (in this example, the water introduction portion 107) that introduces the dispersion liquid into the reaction chamber 101 after decomposition, and a suspension discharge portion 110 that discharges the suspension in which the fine particles are dispersed in the dispersion liquid. This can suppress aggregation of fine particles generated by the hydrothermal reaction. As a result, the chlorine concentration of the fine particles can be reduced by the cleaning in the cleaning device 20, and therefore the chlorine concentration of the solid fuel can be reduced.

Further, in the solid fuel production system 1 of the first embodiment, the cleaning device 20 includes a large-diameter fine particle removal unit 22 that removes large-diameter fine particles, which are fine particles having a particle diameter larger than a predetermined reference particle diameter, from the cleaned fine particles.

The larger the particle size of the fine particles, the higher the possibility that the decomposition by the hydrothermal reaction is insufficient. Further, the larger the particle size of the fine particles, the higher the possibility of aggregates. Therefore, the larger the particle diameter, the higher the chlorine concentration of the fine particles becomes. Therefore, as in the solid fuel production system 1, the chlorine concentration of the solid fuel can be reduced by removing large-diameter fine particles larger than the reference particle diameter.

Further, the solid fuel production system 1 of the first embodiment includes a large-diameter fine particle supply unit 25 that supplies the removed large-diameter fine particles to the reaction chamber 101.

This allows the particles or aggregates that have not been sufficiently decomposed by the hydrothermal reaction to be decomposed into fine particles again by the hydrothermal reaction. Therefore, the amount of the generated solid fuel can be suppressed from decreasing.

Further, in the solid fuel production system 1 of the first embodiment, the cleaning device 20 includes a steam cleaning portion 23 that cleans the fine particles using steam after cleaning.

Thus, since the temperature of the steam is higher than that of the suspension, chlorine-containing substances that have not dissolved out by stirring the suspension can be removed from the fine particles. As a result, the chlorine concentration of the solid fuel can be reduced.

The solid fuel production system 1 of the first embodiment is of a batch type. The solid fuel production system 1 may be a continuous system.

The number of steam purge sections provided in the solid fuel production system 1 may be 2 or more. The number of the cleaning units provided in the solid fuel production system 1 may be 1, 3 or more.

(solid Fuel)

Next, a solid fuel produced by using the solid fuel production system 1 of the first embodiment will be described.

The Hardgrove grindability index of the solid fuel measured according to JIS M8801 is a value of 100 to 200. It is noted that the Hardgrove grindability index of coal is about 40. Thus, the solid fuel has a higher Hardgrove grindability index than coal.

In addition, the chlorine concentration of the solid fuel was measured in accordance with JIS Z7302-6 to be a value of 0.05% by weight to 0.1% by weight. Therefore, the chlorine concentration of the solid fuel is 0.1 wt% or less.

The calorific value of the solid fuel measured according to JIS Z7302-2 is 20MJ/kg to 40 MJ/kg. Therefore, the calorific value of the solid fuel is 20MJ/kg or more.

In this way, the solid fuel of the first embodiment is manufactured from a raw material containing waste plastic. Further, the solid fuel has a Hardgrove grindability index higher than that of coal, and the solid fuel has a chlorine concentration of 0.1 wt% or less.

However, when the pulverization of the solid fuel is lower than that of coal, for example, in a coal boiler used for thermal power generation, there is a possibility that the solid fuel cannot be pulverized. Further, if the chlorine concentration of the solid fuel is not sufficiently reduced, there is a possibility that a member which the combustion gas or the combustion ash contacts may corrode.

In contrast, according to the solid fuel of the first embodiment, for example, in a coal boiler used for thermal power generation, the solid fuel can be used instead of a part of coal.

< first modification of the first embodiment >

Next, a solid fuel production system according to a first modification of the first embodiment will be described. The solid fuel production system according to the first modification of the first embodiment differs from the solid fuel production system according to the first embodiment in that it does not include a steam purge unit. Hereinafter, the following description will focus on the differences. In the description of the first modification of the first embodiment, the same or substantially the same reference numerals are used for the same portions as those used in the first embodiment.

(constitution)

As shown in fig. 4, in the solid fuel production system 1A according to the first modification of the first embodiment, the cleaning device 20 is replaced with a cleaning device 20A in the solid fuel production system 1 according to the first embodiment.

In the cleaning apparatus 20A, the steam cleaning unit 23 is replaced with a solid-liquid separation unit 26A in the cleaning apparatus 20 of the first embodiment. The solid-liquid separation section 26A includes a solid-liquid separator similar to the steam cleaning section 23. The solid-liquid separation unit 26A causes the solid-liquid separator to capture fine particles contained in the supplied suspension and allows the supplied suspension to pass through portions other than the fine particles (in other words, the separation liquid). The solid-liquid separation unit 26A supplies the fine particles captured by the solid-liquid separator to the second cleaning unit 24, and supplies the separated liquid having passed through the solid-liquid separator to the separated liquid reservoir unit 51.

With such a configuration, the solid fuel production system 1A according to the first modification of the first embodiment can also achieve the same operation and effect as the solid fuel production system 1 according to the first embodiment.

< second modification of the first embodiment >

Next, a solid fuel production system according to a second modification of the first embodiment will be described. A solid fuel production system according to a second modification of the first embodiment differs from the solid fuel production system according to the first embodiment in that the first purge portion is not provided. Hereinafter, the following description will focus on the differences. In the description of the second modification of the first embodiment, the same or substantially the same reference numerals as those used in the first embodiment are used to designate the same or substantially the same components.

(constitution)

As shown in fig. 5, in the solid fuel production system 1F according to the second modification of the first embodiment, the cleaning device 20 is replaced with a cleaning device 20F in the solid fuel production system 1 according to the first embodiment.

The cleaning device 20F has the same configuration as the cleaning device 20 of the first embodiment, except that it does not include the first cleaning unit 21.

With such a configuration, the solid fuel production system 1F according to the second modification of the first embodiment can also provide the same operation and effect as those of the solid fuel production system 1 according to the first embodiment.

(Experimental example)

Next, experimental examples performed to investigate changes in the chlorine concentration of the solid fuel with respect to the particle diameter of the solid fuel and the presence or absence of purging will be described.

In the experimental example, an uncleaned sample of the solid fuel and a cleaned sample of the solid fuel were generated using the solid fuel production system 1F of the second modification of the first embodiment.

The unwashed samples were generated as follows: after the hydrothermal reaction is completed, the dispersion liquid is not supplied to the reaction chamber 101, and the fine particles generated by the hydrothermal reaction are dried by the drying device 40.

The washed sample was generated as above: the large-diameter microparticles removed by the large-diameter microparticle removal unit 22 are supplied to the steam cleaning unit 23, cleaned by the steam cleaning unit 23 and the second cleaning unit 24, dehydrated by the dehydration device 30, and dried by the drying device 40.

The chlorine concentrations of the unwashed and washed samples, as measured according to JIS Z7302-6, are shown in Table 1. In this example, the chlorine concentration was measured for each of 7 particle size ranges. The particle size range is the range of particle sizes for the unwashed sample and the washed sample. In this example, the particle size ranges in table 1 show: the particle diameters of the unwashed sample and the washed sample are included in the range of the numerical value on the left side of "-" or more and smaller than the numerical value on the right side of "-".

[ Table 1]

FIG. 6 is a graph showing changes in the chlorine concentration with respect to the particle diameter shown in Table 1.

As shown in fig. 6, the chlorine concentration of the washed samples was not higher than that of the unwashed samples in any particle size range. In the case where the particle size is smaller than 1180 μm, the chlorine concentration of the washed sample is greatly reduced by washing as compared with the case where the particle size is 1180 μm or more. The chlorine concentration of the washed sample was 0.30 wt% or less in the case of a particle size of less than 1180 μm.

Further, when the particle size is smaller than 600 μm, the chlorine concentration of the washed sample is further significantly reduced by washing compared with the case where the particle size is 600 μm or more. In the case where the particle diameter is less than 600. Mu.m, the chlorine concentration of the washed sample is 0.24 wt% or less.

Furthermore, when the particle size is less than 425 μm, the chlorine concentration of the washed sample is further significantly reduced by washing compared to the case where the particle size is 425 μm or more. In the case where the particle diameter is less than 425 μm, the chlorine concentration of the washed sample is 0.19 wt% or less.

Further, when the particle size is less than 105 μm, the chlorine concentration of the washed sample is reduced to the maximum extent by washing as compared with the case where the particle size is 105 μm or more. In the case where the particle diameter is less than 105 μm, the chlorine concentration of the washed sample is 0.06 wt% or less.

Therefore, the solid fuel produced by using the solid fuel production system 1F of the second modification of the first embodiment has a concentration of 0.30 wt% or less when the average particle diameter is smaller than 1180 μm. The solid fuel produced by using the solid fuel production system 1F according to the second modification of the first embodiment has a concentration of 0.24 wt% or less when the average particle size is smaller than 600 μm. The solid fuel produced by using the solid fuel production system 1F according to the second modification of the first embodiment has a concentration of 0.19 wt% or less when the average particle size is less than 425 μm. The solid fuel produced by using the solid fuel production system 1F according to the second modification of the first embodiment has a concentration of 0.06 wt% or less when the average particle size is less than 105 μm.

For example, the average particle diameter may be a particle diameter having a cumulative value of 50% in a particle diameter distribution (in other words, a particle diameter distribution) measured by a laser diffraction/scattering method. The average particle diameter may be a particle diameter having a mode in a particle diameter distribution (in other words, a particle diameter distribution) obtained by a laser diffraction/scattering method.

The solid fuel produced by using the solid fuel production system 1 of the first embodiment, the solid fuel production system 1A of the first modification of the first embodiment, or the solid fuel production systems of the second to fifth embodiments described later is also the same as the solid fuel produced by using the solid fuel production system 1F of the second modification of the first embodiment.

(solid Fuel)

Next, a solid fuel produced by using the solid fuel production system 1F of the second modification of the first embodiment will be described.

In addition, for solid fuels, the average particle size, as determined by laser diffraction/scattering methods, is less than 200 μm.

In addition, the chlorine concentration of the solid fuel was measured in accordance with JIS Z7302-6 to be a value of 0.06 to 0.1% by weight. Therefore, the chlorine concentration of the solid fuel is 0.1 wt% or less.

As described above, the solid fuel of the second modification of the first embodiment is produced from a raw material containing waste plastics. Further, the solid fuel has a Hardgrove grindability index higher than that of coal, an average particle diameter of less than 200 μm, and a chlorine concentration of 0.1 wt% or less.

In contrast, the solid fuel according to the second modification of the first embodiment can be used instead of a part of coal in a coal boiler used for thermal power generation, for example.

< second embodiment >

Next, a solid fuel production system according to a second embodiment will be described. The solid fuel production system according to the second embodiment differs from the solid fuel production system according to the first embodiment in that recovered water is supplied to the hydrothermal reaction device. Hereinafter, the differences will be mainly explained. In the description of the second embodiment, the same or substantially the same reference numerals as those used in the first embodiment are used for the same parts.

(constitution)

As shown in fig. 7, in the solid fuel production system 1B of the second embodiment, the vapor recovery unit 16 is replaced with a vapor recovery unit 16B in the solid fuel production system 1 of the first embodiment.

The vapor recovery unit 16B includes a water storage tank for storing water. The steam recovery unit 16B introduces steam discharged from the reaction chamber 101 into the water stored in the water storage tank.

Further, the steam recovery unit 16B includes a chlorine concentration detection unit 161B. The chlorine concentration detector 161B may be referred to as a chlorine concentration detector for the recovered water. The chlorine concentration detector 161B introduces steam into the water stored in the water storage tank, and then detects the chlorine concentration of the recovered water, which is the water stored in the water storage tank.

The steam recovery unit 16B supplies the recovered water stored in the water storage tank to the reaction chamber 101 after the decomposition of the raw material by the hydrothermal reaction when the chlorine concentration detected by the chlorine concentration detection unit 161B is lower than a predetermined first reference concentration. On the other hand, when the chlorine concentration detected by the chlorine concentration detector 161B is higher than the first reference concentration, the steam recovery unit 16B supplies the recovered water stored in the reservoir tank to the wastewater treatment apparatus 52.

With such a configuration, the solid fuel production system 1B according to the second embodiment can also provide the same operation and effect as those of the solid fuel production system 1 according to the first embodiment.

The solid fuel production system 1B according to the second embodiment further includes a water storage tank for storing water, and a steam recovery unit 16B for introducing steam discharged from the reaction chamber 101 into the stored water. The steam recovery unit 16B includes a chlorine concentration detection unit 161B, and the chlorine concentration detection unit 161B detects the chlorine concentration of the recovered water, which is the stored water, after the steam is introduced. The vapor recovery unit 16B supplies the recovered water to the reaction chamber 101 after the decomposition of the raw material by the hydrothermal reaction when the detected chlorine concentration is lower than the predetermined first reference concentration.

This allows chlorine-containing substances contained in the steam discharged from the reaction chamber 101 to be dissolved in the stored water and recovered. Further, by supplying the recovered water to the reaction chamber 101 after the decomposition by the hydrothermal reaction, the amount of the dispersion liquid (in this example, water supplied from the water supply unit 14) separately supplied to the reaction chamber 101 to produce the suspension can be reduced.

However, the higher the chlorine concentration of the recovered water, the less the amount of the chlorine-containing substances contained in the fine particles eluted into the recovered water. Therefore, when the chlorine concentration of the recovered water is lower than the first reference concentration as in the solid fuel production system 1B, the chlorine concentration of the fine particles can be reliably reduced by cleaning in the cleaning device 20 by supplying the recovered water to the reaction chamber 101.

< third embodiment >

Next, a solid fuel production system according to a third embodiment will be described. The solid fuel production system according to the third embodiment differs from the solid fuel production system according to the first embodiment in that recovered water is supplied to the cleaning device. Hereinafter, the following description will focus on the differences. In the description of the third embodiment, the same or substantially the same reference numerals as those used in the first embodiment are used for the same parts.

(constitution)

As shown in fig. 8, in the solid fuel production system 1C of the third embodiment, the vapor recovery unit 16 is replaced with a vapor recovery unit 16C in the solid fuel production system 1 of the first embodiment.

The vapor recovery unit 16C includes a water storage tank for storing water. The steam recovery unit 16C introduces steam discharged from the reaction chamber 101 into the water stored in the water storage tank.

Further, the steam recovery unit 16C includes a chlorine concentration detection unit 161C. The chlorine concentration detector 161C may be referred to as a chlorine concentration detector for the recovered water. The chlorine concentration detector 161C introduces steam into the water stored in the water storage tank, and then detects the chlorine concentration of the recovered water, which is the water stored in the water storage tank.

The steam recovery unit 16C supplies the recovered water stored in the water storage tank to the cleaning tank 241 of the second cleaning unit 24 when the chlorine concentration detected by the chlorine concentration detection unit 161C is lower than a predetermined first reference concentration. On the other hand, when the chlorine concentration detected by the chlorine concentration detector 161C is higher than the first reference concentration, the steam recovery unit 16C supplies the recovered water stored in the reservoir tank to the wastewater treatment apparatus 52.

With such a configuration, the solid fuel production system 1C according to the third embodiment can also provide the same operation and effect as those of the solid fuel production system 1 according to the first embodiment.

Further, the solid fuel production system 1C according to the third embodiment includes a water storage tank for storing water, and a steam recovery unit 16C for introducing steam discharged from the reaction chamber 101 into the stored water. The steam recovery unit 16C includes a chlorine concentration detection unit 161C, and the chlorine concentration detection unit 161C detects the chlorine concentration of the recovered water, which is the stored water, after the introduction of the steam. The steam recovery unit 16C supplies the recovered water to the cleaning device 20 when the detected chlorine concentration is lower than a predetermined first reference concentration.

This allows chlorine-containing substances contained in the steam discharged from the reaction chamber 101 to be recovered by dissolving the chlorine-containing substances in the stored water. Furthermore, by supplying the recovered water to the cleaning device 20, the amount of the cleaning liquid (in this example, the water supplied from the water supply unit 14) separately supplied to the cleaning device 20 can be reduced.

However, the higher the chlorine concentration of the recovered water, the less the amount of the chlorine-containing substances contained in the fine particles eluted into the recovered water. Therefore, when the chlorine concentration of the recovered water is lower than the first reference concentration as in the solid fuel production system 1C, the chlorine concentration of the particulates can be reliably reduced by the cleaning in the cleaning device 20 by supplying the recovered water to the cleaning device 20.

< fourth embodiment >

Next, a solid fuel production system according to a fourth embodiment will be described. The solid fuel production system according to the fourth embodiment differs from the solid fuel production system according to the first embodiment in that the separated liquid is supplied to the hydrothermal reaction device. Hereinafter, the following description will focus on the differences. In the description of the fourth embodiment, the same or substantially the same reference numerals as those used in the first embodiment are used for the same parts.

(constitution)

As shown in fig. 9, in the solid fuel production system 1D of the fourth embodiment, the separation liquid reservoir 51 is replaced with a separation liquid reservoir 51D in the solid fuel production system 1 of the first embodiment.

The separated liquid storage section 51D includes a storage tank for storing the separated liquid supplied from the steam cleaning section 23 and the separated liquid supplied from the dehydration device 30.

Further, the separated liquid storage section 51D includes a chlorine concentration detection section 512D. The chlorine concentration detector 512D may be a separated liquid chlorine concentration detector. The chlorine concentration detector 512D detects the chlorine concentration of the separation liquid stored in the storage tank.

The separated liquid storage unit 51D supplies the separated liquid stored in the storage tank to the reaction chamber 101 after decomposition of the raw material by the hydrothermal reaction when the chlorine concentration detected by the chlorine concentration detection unit 512D is lower than a predetermined second reference concentration. On the other hand, when the chlorine concentration detected by the chlorine concentration detector 512D is higher than the second reference concentration, the separated liquid reservoir 51D supplies the separated liquid stored in the reservoir tank to the wastewater treatment apparatus 52.

With such a configuration, the solid fuel production system 1D according to the fourth embodiment can also provide the same operation and effect as those of the solid fuel production system 1 according to the first embodiment.

Further, the solid fuel production system 1D of the fourth embodiment includes a separation liquid reservoir 51D that stores a separation liquid that is a liquid obtained by separating fine particles from a suspension. The separated liquid storage section 51D includes a chlorine concentration detection section 512D that detects the chlorine concentration of the stored separated liquid. The separated liquid storage unit 51D supplies the separated liquid to the reaction chamber 101 after the decomposition of the raw material by the hydrothermal reaction when the detected chlorine concentration is lower than a predetermined second reference concentration.

Thus, by supplying the separation liquid to the reaction chamber 101 after the decomposition by the hydrothermal reaction, the amount of the dispersion liquid (in this example, water supplied from the water supply unit 14) separately supplied to the reaction chamber 101 to produce the suspension can be reduced.

However, the higher the chlorine concentration of the separation liquid, the smaller the amount of chlorine-containing substances contained in the fine particles eluted into the separation liquid. Therefore, when the chlorine concentration of the separation liquid is lower than the second reference concentration as in the solid fuel production system 1D, the chlorine concentration of the fine particles can be reliably reduced by the cleaning in the cleaning device 20 by supplying the separation liquid to the reaction chamber 101.

< fifth embodiment >

Next, a solid fuel production system according to a fifth embodiment will be described. The solid fuel production system according to the fifth embodiment differs from the solid fuel production system according to the first embodiment in that the separation liquid is supplied to the cleaning device. Hereinafter, the following description will focus on the differences. In the description of the fifth embodiment, the same or substantially the same reference numerals as those used in the first embodiment are used for the same portions.

(constitution)

As shown in fig. 10, in the solid fuel production system 1E of the fifth embodiment, the separation liquid reservoir 51 is replaced with a separation liquid reservoir 51E in the solid fuel production system 1 of the first embodiment.

The separated liquid storage section 51E includes a storage tank for storing the separated liquid supplied from the steam cleaning section 23 and the separated liquid supplied from the dehydration device 30.

Further, the separated liquid storage section 51E includes a chlorine concentration detection section 512E. The chlorine concentration detecting unit 512E may be referred to as a separated liquid chlorine concentration detecting unit. The chlorine concentration detector 512E detects the chlorine concentration of the separation liquid stored in the storage tank.

When the chlorine concentration detected by the chlorine concentration detecting unit 512E is lower than a predetermined second reference concentration, the separation liquid reserving unit 51E supplies the separation liquid reserved in the reserving tank to the cleaning tank 241 of the second cleaning unit 24. On the other hand, when the chlorine concentration detected by the chlorine concentration detector 512E is higher than the second reference concentration, the separated liquid reservoir 51E supplies the separated liquid stored in the reservoir tank to the wastewater treatment apparatus 52.

With such a configuration, the solid fuel production system 1E according to the fifth embodiment can also provide the same operation and effect as those of the solid fuel production system 1 according to the first embodiment.

Further, the solid fuel production system 1E according to the fifth embodiment includes a separation liquid reservoir 51E that stores a separation liquid that is a liquid obtained by separating fine particles from a suspension. The separated liquid storage unit 51E includes a chlorine concentration detection unit 512E for detecting the chlorine concentration of the stored separated liquid. The separated liquid storage unit 51E supplies the separated liquid to the cleaning apparatus 20 when the detected chlorine concentration is lower than a predetermined second reference concentration.

Thus, by supplying the separation liquid to the cleaning device 20, the amount of the cleaning liquid (in this example, water supplied from the water supply unit 14) separately supplied to the cleaning device 20 can be reduced.

However, the higher the chlorine concentration of the separation liquid, the smaller the amount of chlorine-containing substances contained in the fine particles eluted into the separation liquid. Therefore, when the chlorine concentration of the separation liquid is lower than the second reference concentration as in the solid fuel production system 1E, the chlorine concentration of the fine particles can be reliably reduced by the cleaning in the cleaning device 20 by supplying the separation liquid to the cleaning device 20.

The present invention is not limited to the above embodiments. For example, various modifications that can be understood by those skilled in the art may be applied to the above-described embodiments without departing from the scope of the present invention.

Description of the symbols

1,1A,1B,1C,1D,1E,1F: solid fuel production system, 10: hydrothermal reaction apparatus, 101: reaction chamber, 102: stirring body, 103: motor, 104: first raw material introduction portion, 105: second raw material introduction portion, 106: steam introduction portion, 107: water introduction section, 108: hydroxide introduction portion, 109: steam discharge unit, 110: suspension discharge unit, 11: first raw material supply unit, 12: second raw material supply unit, 13: steam supply unit, 14: water supply unit, 15: hydroxide supply unit, 16, 169, 16941: vapor recovery unit, 161b,161c: chlorine concentration detection unit, 20, 20a,20f: cleaning device, 21: first cleaning unit, 211: cleaning tank, 212: stirring body, 213: suspension discharge unit, 22: large-diameter microparticle removal unit, 221: classifier, 23: steam cleaning unit, 231: solid-liquid separator, 24: second cleaning unit, 241: cleaning tank, 242: stirring body, 25: large-diameter particulate supply section, 26A: solid-liquid separation unit, 30: dehydration device, 40: drying device, 51: separation liquid storage unit, 511: storage tank, 512D,512E: chlorine concentration detection unit, 51D,51E: separation liquid reservoir, 52: a wastewater treatment apparatus.

Claims

1. A solid fuel production system for producing solid fuel from a raw material containing waste plastic, comprising a hydrothermal reaction device, a cleaning device, and a separation device,

the hydrothermal reaction device comprises: a reaction chamber that decomposes the raw material into fine particles by hydrothermal reaction; a dispersion liquid introduction unit that introduces the dispersion liquid into the reaction chamber after the decomposition; and a suspension discharge unit that discharges a suspension in which the fine particles are dispersed in the introduced dispersion liquid,

the cleaning device cleans the microparticles by stirring the discharged suspension,

the separation device generates the solid fuel by separating the particulates from the suspension.

2. The solid fuel manufacturing system according to claim 1,

the cleaning apparatus includes a large-diameter particle removal unit that removes large-diameter particles, which are particles having a particle diameter larger than a predetermined reference particle diameter, from the cleaned particles.

3. The solid fuel production system according to claim 2, comprising a fine particle supply unit that supplies the removed large-diameter fine particles to the reaction chamber.

4. A solid fuel manufacturing system according to any one of claims 1 to 3, wherein the cleaning device includes a steam cleaning portion that cleans the fine particles using steam after the cleaning.

5. The solid fuel production system according to any one of claims 1 to 4, comprising a steam recovery unit that includes a water storage tank that stores water and that introduces steam discharged from the reaction chamber into the stored water,

the steam recovery unit includes a recovered water chlorine concentration detection unit that detects a chlorine concentration of the recovered water as the stored water after the introduction, and,

and supplying the recovered water to the reaction chamber after the decomposition when the detected chlorine concentration is lower than a predetermined first reference concentration.

6. The solid fuel production system according to any one of claims 1 to 5, comprising a separation liquid storage unit that stores a separation liquid, the separation liquid being a liquid obtained by separating the fine particles from the suspension,

the separation liquid storage unit includes a separation liquid chlorine concentration detection unit that detects a chlorine concentration of the stored separation liquid, and the separation liquid is supplied to the reaction chamber after the decomposition when the detected chlorine concentration is lower than a predetermined second reference concentration.

7. A solid fuel production method for producing a solid fuel from a raw material containing waste plastic, comprising:

decomposing the raw material into fine particles by hydrothermal reaction in a reaction chamber;

introducing a dispersion into the reaction chamber after the decomposing;

washing the microparticles by stirring the discharged suspension;

generating the solid fuel by separating the particulates from the suspension.

8. A solid fuel produced by decomposing a raw material containing waste plastics into fine particles by a hydrothermal reaction and washing the fine particles,

the solid fuel has an average particle size of less than 1180 μm, and,

the solid fuel has a chlorine concentration of 0.30 wt% or less.

9. The solid fuel according to claim 8,

the solid fuel has an average particle diameter of less than 600 μm, and,

the solid fuel has a chlorine concentration of 0.24 wt% or less.

10. The solid fuel according to claim 8 or 9,

the solid fuel has a higher Hardgrove grindability index than coal.

11. The solid fuel according to any one of claims 8 to 10,

the calorific value of the solid fuel is more than 20 MJ/kg.