CN115335494B

CN115335494B - Solid fuel production system, solid fuel production method, and solid fuel

Info

Publication number: CN115335494B
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: 2024-04-12
Anticipated expiration: 2041-04-23
Also published as: CN115335494A; JP2021175788A; JP6827582B1; WO2021220958A1; KR20220140854A; JP2021175781A; JP6994590B2

Abstract

A solid fuel production system (1) produces solid fuel from a raw material containing waste plastics. 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 apparatus (10) comprises: a reaction chamber for decomposing a raw material into fine particles by a hydrothermal reaction; a dispersion liquid supply unit for supplying a 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. The cleaning device (20) cleans the microparticles by stirring the discharged suspension. The separation means (30, 40) generates a solid fuel by separating particles from the suspension.

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

Solid fuel manufacturing systems are known that manufacture solid fuel from raw materials that include waste plastics. For example, the solid fuel production system described in patent document 1 includes a reaction chamber for decomposing organic waste including polyvinyl chloride by hydrothermal reaction. The solid fuel production system supplies the decomposed solid components to the mixing tank, and supplies water to the mixing tank, and performs mixing in the mixing tank, thereby reducing the chlorine concentration of the solid components.

Prior art literature

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. For this reason, for example, in a coal boiler used for thermal power generation, if 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 with combustion gas or combustion ash may be corroded. However, in the above-described solid fuel production system, there is 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 apparatus includes: a reaction chamber for decomposing a raw material into fine particles by a hydrothermal reaction; a dispersion liquid supply unit for supplying a 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. The cleaning device cleans the microparticles by stirring the discharged suspension. The separation device generates solid fuel by separating particles from the suspension.

In another aspect, a solid fuel manufacturing method manufactures a solid fuel from a raw material including waste plastic.

The solid fuel manufacturing method comprises the following steps:

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

after the raw materials are decomposed, introducing a dispersion liquid into a reaction chamber;

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

cleaning the particles by stirring the discharged suspension;

solid fuel is produced by separating particles from a suspension.

In another aspect, the solid fuel is manufactured by decomposing a raw material containing waste plastics into particles by a hydrothermal reaction and cleaning the particles.

In the solid fuel, the average particle diameter of the solid fuel is less than 1180 μm, 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 structure of a solid fuel production system according to the first embodiment.

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

Fig. 3 is a flowchart showing a 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 structure of a solid fuel production system according to a second modification of the first embodiment.

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

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

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

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

Fig. 10 is a block diagram showing the structure of a solid fuel production system according to the 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 plastics.

However, aggregates may be formed by aggregation of fine particles generated by the hydrothermal reaction. The aggregates are hardly decomposed even when stirred together with the dispersion liquid. In addition, chlorine-containing substances that have entered the aggregate are difficult to dissolve out even when stirred together with the dispersion. The chlorine-containing substance is a substance containing chlorine atoms. Therefore, for example, in the case where the dispersion liquid is not supplied to the reaction chamber and the solid component is discharged from the reaction chamber after decomposition by the hydrothermal reaction as in the solid fuel production system described in patent document 1, there is a concern 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 apparatus includes: a dispersion liquid supply unit for supplying a 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 dispersion. This can suppress aggregation of fine particles generated by the hydrothermal reaction. As a result, the chlorine concentration of the particulates 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 a solid fuel from a raw material including waste plastics. In this example, the raw materials are composed of a first raw material and a second raw material.

In this example, the first raw material is waste plastic. Waste plastics are waste materials comprising plastics. For example, waste plastics include containers that package goods. In this example, the waste plastic contains a chlorine-containing substance such as salt and polyvinyl chloride attached to the container.

In this example, the second feedstock is biomass. For example, biomass is waste paper, sludge, grass, straw, wheat straw, rice hulls, or woody biomass (e.g., wood chips, meta-wood, or woody waste, etc.), and the like. For example, wood waste is bark or sawdust, wood chips, building disintegrated materials, or pruned wood generated at the time of making the wood.

The solid fuel production system 1 includes a hydrothermal reaction unit 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 unit 20, a large-diameter fine particle supply unit 25, a dehydration unit 30, a drying unit 40, a separated liquid storage unit 51, and a drain treatment unit 52.

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

The reaction chamber 101 is a space provided inside the hydrothermal reaction unit 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 subcritical state water (in other words, subcritical water). For example, the subcritical water maintained in the reaction chamber 101 has a pressure of 1.5MPa to 3.5 MPa. For example, the temperature of subcritical water maintained in reaction chamber 101 is a temperature of 180 ℃ to 250 ℃.

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

The stirring body 102 includes a plurality of stirring blades. The number of stirring blades provided in the stirring body 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 unit 10 may include a baffle plate on the inner wall of the reaction chamber 101.

The stirring body 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 stirring body 102 stirs the material introduced into the reaction chamber 101.

In this example, the stirring body 102 is rotationally driven in the first rotational direction, so that the substance introduced into the reaction chamber 101 moves 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, so that 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 introduction unit 104 introduces the first raw material supplied from the first raw material supply unit 11 into the reaction chamber 101. The first raw material introduction unit 104 adjusts the amount of the first raw material introduced into the reaction chamber 101. The number of the first raw material introduction units 104 included in the hydrothermal reaction unit 10 may be 2 or more.

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. The second raw material introduction unit 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 included in the hydrothermal reaction apparatus 10 may be 2 or more.

The hydrothermal reaction apparatus 10 may also include a raw material introduction portion for introducing 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 introduction portion 104 and the second raw material introduction portion 105.

The steam introduction unit 106 introduces the steam supplied from the steam supply unit 13 into the reaction chamber 101. The steam introduction 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 steam introduction sections 106 included in the hydrothermal reaction unit 10 may be 2 or more.

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

The hydroxide introducing portion 108 introduces the hydroxide supplied from the hydroxide supplying portion 15 into the reaction chamber 101. The hydroxide introducing portion 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 occurs 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 hydroxide ions generated from the hydroxide react with polyvinyl chloride contained in the waste plastic, whereby chlorine contained in the polyvinyl chloride is substituted with hydroxyl groups.

In addition, it is presumed that the chloride ions generated by this reaction react with calcium ions generated by the hydroxide, thereby generating calcium chloride. Further, it is assumed that the generated calcium chloride is mixed with the fine particles generated by the hydrothermal reaction. As described later, calcium chloride mixed in the fine particles is removed by washing in the washing apparatus 20. In this way, the chlorine concentration of the particles after washing can be sufficiently reduced.

The hydroxide may be a hydroxide of a metal other than calcium (for example, aluminum, nickel, iron, magnesium, zinc, copper, sodium, or the like). In addition, ammonia may be used in place of hydroxide in the solid fuel production system 1. The number of hydroxide introducing parts 108 provided 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 assumed that the steam contains chlorine-containing substances. The steam discharge unit 109 includes a valve for opening and closing a passage that communicates between the reaction chamber 101 and the steam recovery unit 16. The number of the steam discharge units 109 included in the hydrothermal reaction unit 10 may be 2 or more.

The steam 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 drain treatment device 52.

As shown in fig. 2, the suspension discharge section 110 discharges the suspension in the reaction chamber 101 to the outside of the hydrothermal reaction unit 10. In this example, the suspension is a dispersion in which particles produced by a hydrothermal reaction in the reaction chamber 101 are dispersed in a dispersion (water in this example) introduced by the water introduction portion 107.

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

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

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

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

The stirring body 212 includes stirring blades. The number of stirring blades provided in the stirring body 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. The first cleaning unit 21 may include a baffle on the inner wall of the 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 this configuration, the stirring body 212 stirs the material (suspension in this example) introduced into the cleaning tank 211.

The first cleaning unit 21 may introduce the water supplied from the water supply unit 14 into the cleaning tank 211. The first cleaning unit 21 may introduce the hydroxide supplied from the hydroxide supply unit 15 to the cleaning tank 211.

In this example, the first cleaning section 21 includes a heater, not shown, and heats the material introduced into the cleaning tank 211 by heat generated by the heater. For example, the first cleaning unit 21 maintains the temperature of the substance introduced into the 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 this configuration, the first cleaning section 21 cleans the particles by heating and stirring the suspension discharged from the reaction chamber 101. The first cleaning unit 21 may clean the particles by stirring the suspension without heating the suspension.

The suspension discharging portion 213 discharges the suspension in the cleaning tank 211 to the outside of the first cleaning portion 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 particle removing unit 22 includes a classifier 221. The suspension discharged from the suspension discharge unit 213 is supplied to the classifier 221. The classifier 221 captures large-diameter particles, which are particles having a larger particle diameter than a predetermined reference particle diameter, among the particles contained in the supplied suspension, and passes through the portions other than the large-diameter particles in the supplied suspension. In this example, the reference particle diameter was 0.2mm. The reference particle diameter may be 0.1mm to 5mm in length.

In this example, the classifier 221 is a wedge wire screen. In this example, the interval between wedge wires adjacent to each other is substantially 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 punched metal mesh, or a porous body. The large-diameter fine particle removal unit 22 may be realized by a solid-liquid separation device such as a Slit Saver.

With this configuration, the large-diameter particle removal unit 22 removes large-diameter particles from the particles washed by the first washing unit 21.

The large-diameter particle removing section 22 supplies the large-diameter particles captured by the classifier 221 to the large-diameter particle supply section 25. Further, the large-diameter particle removing unit 22 supplies the suspension having passed through the classifier 221 to the steam cleaning unit 23.

The steam cleaning section 23 includes a solid-liquid separator 231. The suspension having passed through the classifier 221 is supplied to the solid-liquid separator 231. The solid-liquid separator 231 captures fine particles contained in the supplied suspension, and passes through a portion other than the fine particles in the supplied suspension (in other words, the separated liquid).

In this example, the solid-liquid separator 231 is a wedge wire screen. The interval between wedge wires 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 sprays the steam supplied from the steam supply unit 13 onto the fine particles captured by the solid-liquid separator 231, thereby cleaning the fine particles with the steam.

The steam cleaning unit 23 supplies the particles, which are captured by the solid-liquid separator 231 and cleaned with steam, to the second cleaning unit 24. The steam cleaning unit 23 further 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 fine particles are supplied from the steam cleaning unit 23 to the cleaning tank 241. With this configuration, the cleaning tank 241 stores a suspension in which the fine particles cleaned by the steam cleaning section 23 are dispersed in the water supplied from the water supply section 14.

The stirring body 242 includes stirring blades. The number of stirring blades provided in 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 unit 24 may include a baffle on the inner wall of the cleaning tank 241.

The stirring body 242 is rotatably supported inside the cleaning tank 241 and is driven to rotate by a motor, not shown. With this structure, the stirring body 242 stirs the material (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 material introduced into the cleaning tank 241 by heat generated by the heater. For example, the second cleaning unit 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 this configuration, the second cleaning section 24 cleans the fine particles by heating and stirring the suspension in which the fine particles cleaned by the steam cleaning section 23 are dispersed in water. The second cleaning unit 24 may clean the particles by stirring the suspension without heating the suspension.

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

The large-diameter particle supply unit 25 supplies the large-diameter particles removed by the large-diameter particle removal unit 22 to the reaction chamber 101. In this example, the large-diameter particle supply unit 25 supplies large-diameter particles to the reaction chamber 101 via the first raw material introduction unit 104. The hydrothermal reaction apparatus 10 may further include a large-diameter particle introduction unit for introducing large-diameter 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 washing unit 24, thereby separating the separated liquid from the suspension. In this example, the dewatering device 30 is a press-filter type dewatering device. The dewatering device 30 may be a dewatering device other than a filter press type (for example, a screw filter press type, a belt filter press type, or a centrifugal separation type).

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

The drying device 40 generates a solid fuel by drying the dehydrated cake supplied from the dehydrating device 30. In this example, the solid fuel produced by the drying device 40 is in the form of fine powder or granules.

In this way, in this example, the dewatering device 30 and the drying device 40 constitute a separation device that generates solid fuel by separating fine particles from the suspension washed by the washing device 20.

As shown in fig. 1 and 2, the separation liquid storage unit 51 includes a storage tank 511 for storing the separation liquid supplied from the steam cleaning unit 23 and the separation liquid supplied from the dewatering device 30. The separation liquid storage unit 51 supplies the stored separation liquid to the drainage treatment device 52.

The drain treatment device 52 performs a treatment (in other words, a cleaning treatment) of cleaning the separation liquid supplied from the separation liquid storage unit 51 and the recovered water supplied from the steam recovery unit 16. In this example, the cleaning treatment includes a treatment of removing chlorine-containing substances contained in the separation liquid and the recovered water.

The solid fuel production system 1 may be provided with a forming device for forming the dehydrated cake into a predetermined shape (for example, a rod shape, etc.), 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 unit 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. In this way, the raw material is supplied to the reaction chamber 101 of the hydrothermal reaction unit 10 (step S101).

Next, in the hydrothermal reaction unit 10, the steam introduction unit 106 introduces the steam supplied from the steam supply unit 13 into the reaction chamber 101, the water introduction unit 107 introduces the water supplied from the water supply unit 14 into the reaction chamber 101, and the hydroxide introduction unit 108 introduces the hydroxide supplied from the hydroxide supply unit 15 into the reaction chamber 101. In this way, steam, water and hydroxide are supplied to the reaction chamber 101 of the hydrothermal reaction unit 10 (step S102).

Next, the hydrothermal reaction unit 10 rotates the stirring body 102 to stir the material introduced into the reaction chamber 101, and holds water (subcritical water in this example) having a predetermined pressure and a predetermined temperature in the reaction chamber 101 for a predetermined time, thereby decomposing the raw material into fine particles by the hydrothermal reaction (step S103).

Next, in the hydrothermal reaction unit 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 into the reaction chamber 101. In this way, steam is discharged from the reaction chamber 101 of the hydrothermal reaction unit 10, and the dispersion liquid is supplied to the reaction chamber 101 (step S104). Thus, the particles produced by the hydrothermal reaction do not dry in the reaction chamber 101, and a suspension in which the particles produced by the hydrothermal reaction are dispersed in a dispersion (in this example, water) is produced.

Next, in the hydrothermal reaction unit 10, the suspension discharge unit 110 discharges the suspension in the reaction chamber 101 to the outside of the hydrothermal reaction unit 10, and thereby supplies the suspension to the cleaning tank 211 of the first cleaning unit 21 (step S105). At this time, in this example, the stirring body 102 of the hydrothermal reaction unit 10 is rotationally driven in the first rotational direction. Thereby, the suspension in the reaction chamber 101 is moved so as to approach the suspension discharge portion 110.

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

Next, in the cleaning apparatus 20, the large-diameter particle removing section 22 captures the large-diameter particles in the supplied suspension by the classifier 221, thereby removing the large-diameter particles from the suspension (step S107).

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

Further, the large-diameter particle removing part 22 of the cleaning apparatus 20 supplies the suspension having passed through the classifier 221 to the steam cleaning part 23.

Next, the steam cleaning unit 23 of the cleaning apparatus 20 captures fine particles contained in the supplied suspension by the solid-liquid separator 231, thereby separating the fine particles and the separated liquid from the suspension. Further, in the cleaning apparatus 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 apparatus 20, the steam cleaning unit 23 supplies the fine particles, which have been captured by the solid-liquid separator 231 and cleaned with steam, to the second cleaning unit 24. The steam cleaning unit 23 of the cleaning device 20 supplies the separation liquid having passed through the solid-liquid separator 231 to the separation liquid storage unit 51.

Next, in the cleaning apparatus 20, the second cleaning unit 24 disperses the fine particles supplied from the steam cleaning unit 23 in the cleaning liquid stored in the cleaning tank 241 to generate a suspension, and in the cleaning tank 241, the generated suspension is heated and stirred to clean the fine particles (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 dewatering device 30.

Next, the dewatering device 30 dewaters the suspension supplied from the second washing section 24, thereby separating the separated 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 storage 51.

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

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

Thus, the solid fuel manufacturing system 1 manufactures solid fuel from raw materials including waste plastics. The solid fuel production system 1 may repeatedly perform the above-described operations.

As described above, the solid fuel production system 1 of the first embodiment produces solid fuel from a raw material including waste plastics. The solid fuel production system 1 includes a hydrothermal reaction apparatus 10, a washing apparatus 20, and a separation apparatus (in this example, a dehydration apparatus 30 and a drying apparatus 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 liquid discharge unit 110. The reaction chamber 101 decomposes the raw material into fine particles by a hydrothermal reaction. The dispersion liquid introduction portion introduces a 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. The cleaning device 20 cleans the microparticles by stirring the discharged suspension. The separation device generates solid fuel by separating particles from the suspension.

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

In contrast, according to the solid fuel production system 1, the hydrothermal reaction unit 10 includes a dispersion liquid introduction unit (in this example, the water introduction unit 107) for introducing the dispersion liquid into the reaction chamber 101 after decomposition, and a suspension liquid discharge unit 110 for discharging 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 particulates 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 particle removal section 22 that removes, from the cleaned particles, large-diameter particles that are particles having a particle diameter larger than a predetermined reference particle diameter.

The larger the particle diameter of the fine particles, the higher the likelihood of insufficient decomposition by the hydrothermal reaction. In addition, the larger the particle diameter of the fine particles, the higher the probability of being aggregates. Therefore, the larger the particle diameter is, the more easily the chlorine concentration of the fine particles becomes high. Therefore, as in the solid fuel production system 1, the chlorine concentration of the solid fuel can be reduced by removing the 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 particle supply unit 25 that supplies the removed large-diameter particles to the reaction chamber 101.

Thus, the particles or aggregates which are insufficiently decomposed by the hydrothermal reaction can be decomposed into particles again by the hydrothermal reaction. Therefore, the reduction in the amount of the generated solid fuel can be suppressed.

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

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

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

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

(solid fuel)

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

The Hardgrove grindability index measured in accordance with JIS M8801 for solid fuels is a value of 100 to 200. The hadamard grindability index of coal was about 40. Thus, the hadamard grindability index of solid fuels is higher than that of coal.

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

In addition, the calorific value of the solid fuel measured in accordance with JIS Z7302-2 is a value of 20MJ/kg to 40 MJ/kg. Therefore, the calorific value of the solid fuel is 20MJ/kg or more.

Thus, the solid fuel of the first embodiment is produced from a raw material containing waste plastics. Further, the Hardgrove grindability index of the solid fuel is higher than that of coal, and the chlorine concentration of the solid fuel is 0.1 wt% or less.

However, in the case where the pulverizability 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. In addition, if the chlorine concentration of the solid fuel is not sufficiently reduced, there is a possibility that the member contacted with the combustion gas or the combustion ash may be corroded.

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 is different from the solid fuel production system according to the first embodiment in that the steam cleaning section is not provided. 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 portions as those used in the first embodiment are denoted by the same reference numerals.

(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 the cleaning device 20A in the solid fuel production system 1 according to the first embodiment.

In the cleaning apparatus 20A, in the cleaning apparatus 20 according to the first embodiment, the steam cleaning portion 23 is replaced with a solid-liquid separation portion 26A. The solid-liquid separator 26A includes a solid-liquid separator similar to the steam cleaning unit 23. The solid-liquid separator 26A allows the solid-liquid separator to capture the fine particles contained in the supplied suspension and allows the portions other than the fine particles in the supplied suspension (in other words, the separation liquid) to pass through. The solid-liquid separator 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 51.

With such a configuration, the solid fuel production system 1A according to the first modification of the first embodiment can also provide the same operations and effects as those of 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. The solid fuel production system according to the second modification of the first embodiment is different from the solid fuel production system according to the first embodiment in that the first purge portion is not provided. 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 portions as those used in the first embodiment are denoted by the same reference numerals.

(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 the 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 the first cleaning portion 21 is not provided.

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

(Experimental example)

Next, an experimental example performed to examine the change in chlorine concentration of the solid fuel with respect to the particle diameter of the solid fuel and the presence or absence of cleaning will be described.

In the experimental example, an unwashed sample of the solid fuel and a washed sample of the solid fuel were produced using the solid fuel manufacturing system 1F of the second modification of the first embodiment.

Unwashed samples were generated as follows: after the completion of the hydrothermal reaction, the dispersion liquid is not supplied to the reaction chamber 101, and the microparticles produced by the hydrothermal reaction are dried by the drying device 40.

The washed samples were generated as above: the large-diameter particles removed by the large-diameter particle removing section 22 are supplied to the steam cleaning section 23, cleaned by the steam cleaning section 23 and the second cleaning section 24, dehydrated by the dehydrating device 30, and dried by the drying device 40.

The chlorine concentrations measured in accordance with JIS Z7302-6 for the unwashed samples and the washed samples are shown in Table 1. In this example, chlorine concentrations were measured for each of the 7 particle size ranges. The particle size range is the range of particle sizes for both unwashed and washed samples. In this example, the particle size ranges in table 1 represent: the particle diameters of the unwashed sample and the washed sample are included in a range of a value on the left side of "-" or more and a value smaller than the right side of "-".

TABLE 1

Fig. 6 is a graph showing the change in chlorine concentration with respect to particle diameter shown in table 1.

As shown in fig. 6, the chlorine concentration of the washed sample was equal to or lower than the chlorine concentration of the unwashed sample in any particle size range. When the particle diameter is smaller than 1180 μm, the chlorine concentration of the washed sample is significantly reduced by washing as compared with the case where the particle diameter 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, in the case where the particle diameter is smaller than 600 μm, the chlorine concentration of the washed sample is further greatly reduced by washing as compared with the case where the particle diameter 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% by weight or less.

Further, in the case where the particle diameter is smaller than 425 μm, the chlorine concentration of the washed sample is further greatly reduced by washing as compared with the case where the particle diameter is 425 μm or more. When the particle diameter is less than 425. Mu.m, the chlorine concentration of the washed sample is 0.19% by weight or less.

Further, in the case where the particle diameter is smaller 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 diameter is 105 μm or more. In the case where the particle diameter is less than 105. Mu.m, the chlorine concentration of the washed sample is 0.06% by weight or less.

Therefore, the solid fuel produced by the solid fuel production system 1F according to 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. In addition, the solid fuel produced by 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 diameter is smaller than 600 μm. In addition, the solid fuel produced by 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 diameter is smaller than 425 μm. In addition, the solid fuel produced by 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 diameter is smaller than 105 μm.

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

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

(solid fuel)

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

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

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

Thus, the solid fuel according to the second modification of the first embodiment is produced from the raw material including the waste plastic. Further, the Hardgrove grindability index of the solid fuel is higher than that of coal, the average particle diameter of the solid fuel is less than 200 mu m, and the chlorine concentration of the solid fuel is below 0.1 weight percent.

In contrast, according to the solid fuel of the second modification 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.

< 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 the recovered water is supplied to the hydrothermal reaction unit. The following description will focus on the differences. In the description of the second embodiment, the same or substantially the same portions as those used in the first embodiment are denoted by the same reference numerals.

(constitution)

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

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

The steam recovery unit 16B further includes a chlorine concentration detection unit 161B. The chlorine concentration detection portion 161B may be referred to as a recovered water chlorine concentration detection portion. The chlorine concentration detection portion 161B detects the chlorine concentration of the water stored in the water storage tank, that is, the recovered water, after introducing steam into the water stored in the water storage tank.

When the chlorine concentration detected by the chlorine concentration detection portion 161B is lower than the predetermined first reference concentration, the steam recovery portion 16B supplies the recovered water stored in the water storage tank to the reaction chamber 101 after decomposition of the raw material by the hydrothermal reaction. On the other hand, when the chlorine concentration detected by the chlorine concentration detection portion 161B is higher than the first reference concentration, the steam recovery portion 16B supplies the recovered water stored in the water storage tank to the drain treatment device 52.

With such a configuration, the solid fuel production system 1B according to the second embodiment can also provide the same operations and effects 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 water stored after the steam is introduced. When the detected chlorine concentration is lower than the predetermined first reference concentration, the steam recovery unit 16B supplies the recovered water to the reaction chamber 101 after decomposition of the raw material by the hydrothermal reaction.

This allows chlorine-containing substances contained in the vapor 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, the water supplied from the water supply unit 14) separately supplied to the reaction chamber 101 for generating the suspension can be reduced.

However, the higher the chlorine concentration of the recovered water, the smaller the amount of chlorine-containing substances contained in the fine particles eluted in the recovered water becomes. Therefore, in the case where 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 particulates can be reliably reduced by the 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 the recovered water is supplied to the washing apparatus. The following description will focus on the differences. In the description of the third embodiment, the same or substantially the same portions as those used in the first embodiment are denoted by the same reference numerals.

(constitution)

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

The steam 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.

The steam recovery unit 16C further includes a chlorine concentration detection unit 161C. The chlorine concentration detection portion 161C may be referred to as a recovered water chlorine concentration detection portion. The chlorine concentration detection portion 161C detects the chlorine concentration of the water stored in the water storage tank, that is, the recovered water, after introducing steam into the water stored in the water storage tank.

The steam recovery unit 16C supplies the recovery 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 detection portion 161C is higher than the first reference concentration, the steam recovery portion 16C supplies the recovered water stored in the water storage tank to the drain treatment device 52.

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

The solid fuel production system 1C according to the third embodiment further 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 water stored after the steam is introduced. 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 vapor discharged from the reaction chamber 101 to be dissolved in the stored water and recovered. Further, 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 smaller the amount of chlorine-containing substances contained in the fine particles eluted in the recovered water. Therefore, in the case where 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 unit. The following description will focus on the differences. In the description of the fourth embodiment, the same or substantially the same portions as those used in the first embodiment are denoted by the same reference numerals.

(constitution)

As shown in fig. 9, in the solid fuel production system 1D according to the fourth embodiment, in the solid fuel production system 1 according to the first embodiment, the separated liquid storage 51 is replaced with the separated liquid storage 51D.

The separation liquid storage unit 51D includes a storage tank for storing the separation liquid supplied from the steam cleaning unit 23 and the separation liquid supplied from the dewatering device 30.

The separated liquid storage unit 51D further includes a chlorine concentration detection portion 512D. The chlorine concentration detection portion 512D may be referred to as a separated liquid chlorine concentration detection portion. The chlorine concentration detection portion 512D detects the chlorine concentration of the separated liquid stored in the storage tank.

When the chlorine concentration detected by the chlorine concentration detection portion 512D is lower than the predetermined second reference concentration, the separation liquid storage portion 51D supplies the separation liquid stored in the storage tank to the reaction chamber 101 after the raw material is decomposed by the hydrothermal reaction. On the other hand, when the chlorine concentration detected by the chlorine concentration detection portion 512D is higher than the second reference concentration, the separated liquid storage portion 51D supplies the separated liquid stored in the storage tank to the drain treatment device 52.

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

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

Thus, after the decomposition by the hydrothermal reaction, by supplying the separation liquid to the reaction chamber 101, the amount of the dispersion liquid (in this example, the water supplied from the water supply unit 14) that is separately supplied to the reaction chamber 101 to generate 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 in the separation liquid. Therefore, in the case where 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 particulates 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 is different from the solid fuel production system according to the first embodiment in that a separation liquid is supplied to a cleaning device. The following description will focus on the differences. In the description of the fifth embodiment, the same or substantially the same portions as those used in the first embodiment are denoted by the same reference numerals.

(constitution)

As shown in fig. 10, in the solid fuel production system 1E according to the fifth embodiment, in the solid fuel production system 1 according to the first embodiment, the separated liquid storage 51 is replaced with the separated liquid storage 51E.

The separation liquid storage unit 51E includes a storage tank for storing the separation liquid supplied from the steam cleaning unit 23 and the separation liquid supplied from the dewatering device 30.

The separated liquid reservoir 51E further includes a chlorine concentration detection portion 512E. The chlorine concentration detection portion 512E may be referred to as a separated liquid chlorine concentration detection portion. The chlorine concentration detection portion 512E detects the chlorine concentration of the separated liquid stored in the storage tank.

When the chlorine concentration detected by the chlorine concentration detection portion 512E is lower than the predetermined second reference concentration, the separation liquid storage portion 51E supplies the separation liquid stored in the storage tank to the cleaning tank 241 of the second cleaning portion 24. On the other hand, when the chlorine concentration detected by the chlorine concentration detection portion 512E is higher than the second reference concentration, the separated liquid storage portion 51E supplies the separated liquid stored in the storage tank to the drain treatment device 52.

With such a configuration, the solid fuel production system 1E according to the fifth embodiment can also provide the same operations and effects 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 storage unit 51E for storing a separation liquid, which is a liquid from which fine particles are separated from a suspension. The separation liquid storage unit 51E includes a chlorine concentration detection unit 512E for detecting the chlorine concentration of the stored separation liquid. The separation liquid reservoir 51E supplies the separation liquid to the cleaning device 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, 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 separation liquid, the smaller the amount of chlorine-containing substances contained in the fine particles eluted in the separation liquid. Therefore, in the case where 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 particulates 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 embodiment. For example, various modifications which can be understood by those skilled in the art may be applied to the above-described embodiments within the scope not departing from the gist of the present invention.

Symbol description

1,1a,1b,1c,1d,1e,1f: solid fuel manufacturing system, 10: hydrothermal reaction apparatus, 101: reaction chamber, 102: stirring body, 103: motor, 104: first raw material introduction sections, 105: second raw material introduction section, 106: steam introduction part, 107: water introduction portion, 108: hydroxide introduction part, 109: steam discharge unit, 110: suspension discharge unit, 11: first raw material supply units, 12: second raw material supply unit, 13: steam supply unit, 14: water supply unit, 15: hydroxide supply sections 16, 16b,16c: vapor recovery units, 161b,161c: chlorine concentration detection sections 20, 20a,20f: cleaning device, 21: first cleaning unit, 211: cleaning tank, 212: stirring body, 213: suspension discharge unit, 22: large-diameter particle removal unit, 221: grading body, 23: steam cleaning section, 231: solid-liquid separator, 24: second cleaning section, 241: cleaning tank, 242: stirring body, 25: large-diameter particle supply unit, 26A: solid-liquid separation unit, 30: dewatering device, 40: drying device, 51: separation liquid storage unit, 511: reservoir tank 512d,512e: chlorine concentration detection sections 51d,51e: separation liquid storage unit, 52: a drainage treatment device.

Claims

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

the hydrothermal reaction apparatus includes: a reaction chamber for decomposing the raw material into fine particles by a hydrothermal reaction; a hydroxide introduction unit for introducing an aqueous solution of hydroxide into the reaction chamber; a dispersion liquid introduction unit for introducing a dispersion liquid into the reaction chamber after the decomposition; and a suspension discharge unit for discharging a suspension in which the fine particles are dispersed in the introduced dispersion,

the cleaning device cleans the fine particles by stirring the discharged suspension,

the separation means generates the solid fuel by separating the particles from the suspension,

the cleaning device 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.

2. The solid fuel production system according to claim 1, comprising a fine particle supply unit that supplies the removed large-diameter fine particles to the reaction chamber.

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

the cleaning device includes a steam cleaning section that cleans the fine particles with steam after the cleaning.

4. The solid fuel production system according to claim 1 or 2, comprising a vapor recovery unit that includes a water storage tank for storing water and introduces vapor 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,

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

5. The solid fuel production system according to claim 1 or 2, comprising a separation liquid reservoir for storing a separation liquid in which the fine particles are separated 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 supplies the separation liquid to the reaction chamber after the decomposition when the detected chlorine concentration is lower than a predetermined second reference concentration.

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

introducing an aqueous solution of a hydroxide into the reaction chamber;

decomposing the feedstock into particulates by a hydrothermal reaction in the reaction chamber;

introducing a dispersion into the reaction chamber after the decomposing;

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

washing the microparticles by stirring the discharged suspension;

removing large-diameter particles, which are particles having a particle diameter larger than a predetermined reference particle diameter, from the washed particles;

the solid fuel is produced by separating the large-diameter particulates from a suspension from which the particulates are removed.