JP2020131169A - Heat dehydration system and heat dehydration method - Google Patents

Abstract

To provide a heat dehydration system capable of suppressing fluctuations in moisture content of sludge discharged from dehydrator.SOLUTION: A heat dehydration system comprising a heating dehydrator, a moisture content acquisition unit that acquires the moisture content of sludge discharged from the heating dehydrator, and a heat medium control unit that controls the supply of a heat medium for the heating of sludge in the heating dehydrator in accordance with the moisture content.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thermal dehydration system and a thermal dehydration method.

There is a screw press that controls the press-fitting pressure of sludge supplied to the inner peripheral side of the screen to be constant (for example, Patent Document 1). In this screw press, the moisture content of the dehydrated cake discharged from the screw press is measured, and the chemical injection rate of the coagulant or the rotation speed of the screw shaft is adjusted so that the measured moisture content of the dehydrated cake falls within the set range. Increase or decrease.

Japanese Patent No. 4849380

However, although the chemical injection rate or the rotation speed of the screw shaft is increased or decreased to keep the water content constant, there is a limit to the adjustment of the water content with only these two parameters. For example, when the set value of the water content is set to a low value, the chemical injection rate may reach the upper limit and the rotation speed of the screw shaft may become the lower limit, and it is difficult to adjust to the set water content.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a heat dehydration system and a heat dehydration method capable of suppressing fluctuations in the water content of sludge discharged from a dehydrator. is there.

In order to solve the above-mentioned problems, one aspect of the present invention includes a heat dehydrator, a water content acquisition unit for acquiring the water content of sludge discharged from the heat dehydrator, and the water content according to the water content. It is a heat dehydration system including a heat medium control unit that controls the supply of a heat medium for heating the sludge of the heat dehydrator.

Further, in one aspect of the present invention, the water content acquisition unit acquires the water content of the sludge discharged from the heat dehydrator, and the heat medium control unit obtains the sludge of the heat dehydrator according to the water content. It is a heating and dehydrating method that controls the supply of a heat medium for heating.

As described above, according to the present invention, a heat medium is supplied to the heating / dehydrating machine to heat the concentrated sludge according to the water content of the sludge discharged from the heating / dehydrating machine. As a result, the water content can be adjusted by adjusting the degree of heating by the heat medium, so that the degree of freedom in adjusting the water content is increased, and it becomes easy to adjust to the set water content. As a result, fluctuations in the water content of sludge discharged from the dehydrator can be suppressed.

It is the schematic which shows the structure of the heating dehydration system by one Embodiment of this invention. It is a schematic block diagram explaining the function of the control panel 100. It is a flowchart explaining operation of a heating dehydration system 1.

FIG. 1 is a schematic view showing a configuration of a heat dehydration system according to an embodiment of the present invention.
In this embodiment, the heat dehydration system 1 includes a coagulator 10, a concentrator 20, a concentrated sludge supply pump 30, a coagulant supply pump 40, a coagulant flow meter 45, a press-fit pressure sensor 48, a heat dehydrator 50, and a heat medium supply. It includes a pump 60, a heat medium flow meter 65, a dehydrated sludge pump 70, a water content meter 75, an incineration facility 80, and a control panel 100.

The coagulation device 10 has a coagulation tank in which a polymer coagulant B is added to organic sludge A such as mixed raw sludge generated and supplied from a sewage treatment plant or the like to coagulate. The coagulation tank has a stirring function of stirring the organic sludge A and the polymer coagulant B. The organic sludge A and the polymer flocculant B are agitated and mixed to coagulate. The aggregating device 10 supplies the agglomerated organic sludge A as the agglomerated sludge C to the concentrating device 20.

The concentrating device 20 concentrates the agglomerated sludge C aggregated by the aggregating device 10. For example, the concentrating device 20 has a concentrating filtration screen inside, and the coagulated sludge C supplied from the coagulating device 10 is concentrated by separating water by the concentrating filtration screen 2a.
The concentrated sludge supply pump 30 supplies the concentrated sludge discharged from the concentrator 20 to the heating / dehydrating machine 50 as the concentrated sludge D.

The output side of the coagulant supply pump 40 is connected to a path connecting the concentrated sludge supply pump 30 and the heating / dehydrating machine 50. The coagulant supply pump 40 supplies the coagulant to the concentrated sludge D supplied from the concentrated sludge supply pump 30 to the heat dehydrator 50. The coagulant supplied is at least one of a polymer coagulant and an inorganic coagulant. In this embodiment, the case where the inorganic flocculant E is supplied will be described. As this inorganic flocculant, for example, ferric polysulfate (PFS) can be used.
The coagulant flow meter 45 measures the supply amount of the coagulant supplied from the coagulant supply pump 40 to the concentrated sludge D, and outputs the measurement result to the control panel 100.
The press-fitting pressure sensor 48 detects the press-fitting pressure of the concentrated sludge D supplied to the heating / dehydrating machine 50, and outputs the detection result to the control panel 100.

The heat dehydrator 50 is a sludge dehydrator having a function of heating sludge, and dehydrates the concentrated sludge D supplied from the concentrated sludge supply pump 30. When the inorganic coagulant is supplied to the concentrated sludge D by the coagulant supply pump 40, the heat dehydrator 50 dehydrates the concentrated sludge D after the inorganic coagulant is injected.
In this embodiment, the case where the heating dehydrator 50 is a vertical screw press will be described, but a horizontal screw press or a rotary press may be used as long as it is a dehydrator capable of dehydrating concentrated sludge.

In the heat dehydrator 50, a filtration screen 50B for filtering the concentrated sludge D is arranged in the casing 50A, and the space is concentrated in the first space 50A1 among a plurality of spaces in the casing 50A divided by the filtration screen 50B. Sludge D is supplied.

Further, the heating dehydrator 50 has an internal filtration screen as the second filtration screen 50B, which is arranged in the casing 50A in a cylindrical or conical shape centered on an axis extending in the longitudinal direction coaxial with the casing 50A. The 50Ba and the outer filtration screen 50Bb which forms a cylindrical or conical shape coaxial with the inner filtration screen 50Ba and is arranged in the casing 50A at intervals on the outside of the inner filtration screen 50Ba and twists around the axis. It is housed between the inner filtration screen 50Ba and the outer filtration screen 50Bb in a spiral shape, and is relatively relative to the inner filtration screen 50Ba and the outer filtration screen 50Bb around the above axis by a rotary drive unit 50c such as a motor. It is equipped with a rotatable ribbon screw 50d.

The casing 50A has a bottomed cylindrical shape centered on the axis. The inner filtration screen 50Ba and the outer filtration screen 50Bb are formed of, for example, a wedge wire, a punching metal, or the like.
Then, the concentrated sludge D is supplied to the space between the inner filtration screen 50Ba and the outer filtration screen 50Bb as the first space 50A1.
The space outside the outer filtration screen 50Bb and on the inner peripheral side of the casing 50A is the second space 50A2.
The space inside the internal filtration screen 50Ba is the third space 50A3.

The heating unit 50A4 heats the concentrated sludge D in the heating / dehydrating machine 50. For example, the heating unit 50A4 heats the storage unit containing the concentrated sludge D from the outer peripheral side. In this embodiment, the heating unit 50A4 supplies hot water H from the heat medium supply pump 60 to the space outside the outer filtration screen 50Bb and on the inner peripheral side of the casing 50A (that is, the second space 50A2). As a result, the filtrate and the hot water H are mixed, and as a result, the temperature of the filtrate rises and the temperature of the second space 50A2 rises. Therefore, heat is transferred to the concentrated sludge D through the outer filtration screen 50Bb, and the concentrated sludge D is transferred. Can be heated. In this way, the accommodating portion is heated from the outer peripheral side.
Here, the case where the storage unit is the filtration screen 50B will be described, but it is sufficient that the concentrated sludge D supplied from the outside of the heating / dehydrating machine 50 can be heated. As long as the concentrated sludge D is accommodated, the accommodating portion may be provided with an accommodating portion in which the filtration screen is not formed in the axial direction of the filtration screen 50B, and the accommodating portion may be heated. Further, both the accommodation site and the filtration screen 50B may be heated.

The heating unit 50A4 may heat the entire accommodating portion, but it may also heat a part of the region in the axial direction or a part of the region in the circumferential direction. Good.

Further, the case where the medium for heating the accommodating portion is hot water H will be described, but if the accommodating portion can be heated, another medium may be used. Further, a heater or the like may be used.

The temperature of the hot water H may be higher than the temperature of the concentrated sludge D. The temperature of the hot water H is, for example, in the range of 50 ° C. or higher and lower than 100 ° C., preferably in the range of 60 ° C. or higher and 90 ° C. or lower.
Here, if the temperature of the dehydrated hot water H is less than 50 ° C., the effects of lowering the viscosity of the concentrated sludge D and separating water as described above cannot be sufficiently obtained. Further, when the temperature of the dehydrated hot water H exceeds 100 ° C., the difficulty of handling increases. The higher the temperature of the dehydrated hot water H, the lower the viscosity of the concentrated sludge D and the promotion of water separation due to heat denaturation of proteins. However, as described above, the hot water used in the organic sludge treatment facility is used. When used as dehydrated hot water H, a temperature range of 60 ° C. or higher and 90 ° C. or lower is realistic.

Such hot water H is supplied from the bottom of the casing 50A to the second space 50A2 in the casing 50A. The hot water H thus supplied to the second space 50A2 heats the concentrated sludge D in the first space 50A1. When the concentrated sludge D is heated using the hot water H as a heat medium, the protein of the concentrated sludge D is heat-denatured to separate the retained water. By heating the concentrated sludge D using hot water H as a heat medium, the viscosity of the concentrated sludge D decreases. Then, the concentrated sludge D is filtered by the inner filtration screen 50Ba and the outer filtration screen 50Bb. The filtrate is discharged as drainage J from the drainage pipe 50H raised from the second space 50A2. Further, the dehydrated hot water H cooled by heating the concentrated sludge D is discharged as drainage J from the drainage pipe 50H together with the filtrate.

The connecting plate 50e connects the inner filtration screen 50Ba and the bottom of the outer filtration screen 50Bb. The shape of the connecting plate 50e is an annular plate shape. A supply pipe 50f is connected to the connecting plate 50e.
The supply pipe 50f supplies the concentrated sludge D supplied from the concentrated sludge supply pump 30 into the first space 50A1 from the bottom of the casing 50A. Moisture is separated by the inner filtration screen 50Ba and the outer filtration screen 50Bb while the concentrated sludge D supplied from the supply pipe 50f is conveyed upward by the relative rotation of the ribbon screw 50d. Here, since a large filtration area can be secured, more efficient filtration can be achieved.

Further, a ring plate-shaped substrate 50C is arranged on the upper part of the casing 50A. The outer filtration screen 50Bb is attached and fixed to the inner peripheral portion of the substrate 50C. Further, a lid 50D is arranged in the upper opening of the casing 50A above the substrate 50C, and the internal filtration screen 50Ba is attached to and fixed to the lid 50D.
The rotation drive unit 50c is arranged on the lid body 50D, and rotates the ribbon screw 50d via a cylindrical screw support that covers the upper part of the internal filtration screen 50Ba.
In the present embodiment, the inner filtration screen 50Ba and the outer filtration screen 50Bb are fixed to the casing and the ribbon screw 50d is rotated by the rotation drive unit 50c, but conversely, the ribbon screw 50d is fixed and inside. The filtration screen 50Ba and the outer filtration screen 50Bb may be rotated, or the ribbon screw 50d and the inner filtration screen 50Ba and the outer filtration screen 50Bb may be rotated in opposite directions.

Further, in the casing 50A, the upper space between the substrate 50C and the lid 50D is the discharge chamber 50E, and the annular upper opening of the first space 50A1 in the discharge chamber 50E is the discharge port 50F. Will be done. The discharge port 50F is provided with a back pressure plate 50G having a truncated cone-shaped outer peripheral surface centered on the axis that goes upward toward the outer peripheral side. The dehydrated sludge I dehydrated from the concentrated sludge D while being conveyed upward through the first space 50A1 by the ribbon screw 50d and separated from the concentrated sludge D flows out from the discharge port 50F into the discharge chamber 50E while being pressed by the back pressure plate 50G. It is discharged.
A back pressure plate drive unit is attached to the back pressure plate 50G. The back pressure plate drive unit moves the back pressure plate in the longitudinal direction of the axis so as to have an opening degree according to an instruction from the control panel 100.
The back pressure sensor 50Gs detects the opening degree of the back pressure plate.

The heat medium supply pump 60 supplies the heat medium heated by the heat obtained by burning the sludge discharged from the heat dehydration system to the heat dehydrator 50 (for example, the heating unit 50A4).
The heat medium flow meter 65 measures the amount of hot water supplied from the heat medium supply pump 60 to the heating unit 50A4, and outputs the measurement result to the control panel 100.

The dewatering sludge pump 70 supplies the dewatering sludge I discharged from the heating / dehydrating machine 50 to the incineration facility 80. The water content meter 75 measures the water content of the sludge (dehydrated sludge I) discharged from the heating / dehydrating machine 50, and outputs the measurement result to the control panel 100.

The incinerator 80 incinerates the dewatered sludge I discharged from the heat dewatering machine 50. The incinerator 80 includes an incinerator 81, a boiler 82, and a flue gas treatment tower 83. The incinerator 81 incinerates the dewatered sludge I supplied from the heat dewatering machine 50. If the incinerator 81 can be operated so that the water content of the dehydrated sludge I is near the self-burning point, if the dehydrated sludge I is supplied to the incinerator 81, the dehydrated sludge I is burned without using auxiliary fuel. be able to. Therefore, it is preferable that the fluctuation of the water content of the dehydrated sludge I is small. Further, the fact that the water content of the dehydrated sludge I does not fluctuate from the vicinity of the self-burning point means that it is not necessary to use an auxiliary fuel and it is not necessary to lower the temperature in the incinerator 81 by sprinkling water or the like, which is wasteful dehydration (water content). It is also possible to suppress (too much lowering).

The boiler 82 uses the heat of the combustion exhaust gas from the incinerator 81 to heat the heat medium by a heat exchanger. As the heat medium, for example, water supplied from the flue gas treatment tower 83 can be used. The water supplied from the flue gas treatment tower 83 is heated in the flue gas treatment tower 83, and the boiler 82 further heats the water and then supplies the water to the heat medium supply pump 60. As a result, the heat medium heated by utilizing the heat of the combustion exhaust gas can be supplied to the heating dehydrator 50.

The smoke exhaust treatment tower 83 removes predetermined substances such as dust and impurities from the combustion exhaust gas supplied from the boiler 82 by spraying water supplied from the outside, and exhausts the combustion exhaust gas from the chimney. Further, the flue gas treatment tower 83 heats the water supplied from the outside by the heat of the combustion exhaust gas and supplies the water to the boiler 82.
The control panel 100 controls each part in the heat dehydration system 1. The control panel 100 is composed of a computer or the like.

Next, the control panel 100 will be described.
FIG. 2 is a schematic block diagram illustrating the function of the control panel 100.
The control panel 100 includes a water content acquisition unit 101, a storage unit 102, a water content determination unit 103, a heat medium amount determination unit 104, a heat medium control unit 105, a coagulant determination unit 106, a coagulant control unit 107, and a press-fitting pressure determination unit. 108, back pressure determination unit 110, back pressure control unit 111, control unit 112, communication unit 113 are included.

The water content acquisition unit 101 acquires the water content of the sludge discharged from the heat dehydrator 50. For example, the water content acquisition unit 101 acquires the measurement result of the water content output from the water content meter 75. The water content acquisition unit 101 may be a water content meter 75.

The storage unit 102 stores various information.
For example, the storage unit 102 stores a reference value of the water content.
The stored reference value of the water content may be one (first reference value) or may be plural. When a plurality of water contents are used, for example, an upper limit water content and a lower limit water content can be used as the reference value of the water content.

Further, the storage unit 102 stores a reference value of the heat medium amount.
The stored heat medium amount reference value may be one (second reference value) or may be plural. When a plurality of heat mediums are used, for example, an upper limit heat medium amount and a lower limit heat medium amount can be used as the reference value of the heat medium amount.

In addition, the storage unit 102 stores a reference value of the supply amount of the inorganic flocculant.
The stored reference value of the supply amount of the inorganic flocculant may be one (third reference value) or may be plural. When a plurality of inorganic coagulants are used, for example, the upper limit coagulant amount and the lower limit coagulant amount can be used as the reference value of the supply amount of the inorganic coagulant.

Further, the storage unit 102 stores a reference value of the press-fitting pressure.
The stored press-fitting pressure reference value may be one (fourth reference value) or may be plural. When a plurality of press-fitting pressures are used, for example, an upper limit press-fitting pressure and a lower limit press-fitting pressure can be used as the reference value of the press-fitting pressure.

Further, the storage unit 102 stores a reference value of the pressure of the back pressure plate.
The reference value of the pressure of the back pressure plate to be stored may be one (fifth reference value) or may be a plurality. When a plurality of back pressure plates are used, for example, an upper limit back pressure and a lower limit back pressure can be used as the reference value of the pressure of the back pressure plate.

Such a storage unit 102 may be a storage medium, for example, an HDD (Hard Disk Drive), a flash memory, an EEPROM (Electrically Erasable Programmable Read Only Memory), a RAM (Random Access memory), or a RAM (Random Access memory) Alternatively, it is composed of any combination of these storage media.
For the storage unit 102, for example, a non-volatile memory can be used.

The water content determination unit 103 determines which of the magnitude relations the water content obtained by the water content acquisition unit 101 has with respect to the water content stored in the storage unit 102. In the water content determination unit 103, when the reference value of the water content used for the determination process is one (first reference value), the water content obtained by the water content acquisition unit 101 is larger than the first reference value. Judge whether or not.
When the water content determination unit 103 has two reference values for the water content used in the determination process (upper limit water content and lower limit water content), the water content obtained by the water content acquisition unit 101 is the upper limit water content. It is determined whether or not it is larger (or more), and the water content determination unit 103 determines whether or not the water content obtained by the water content acquisition unit 101 is smaller than (or less than or equal to) the lower limit water content.

The heat medium amount determination unit 104 determines whether the supply amount of the heat medium measured by the heat medium flow meter 65 has a magnitude relationship with the reference value of the heat medium amount stored in the storage unit 102. ..
Specifically, when the water content obtained by the water content acquisition unit 101 is larger than the reference water content, the heat medium amount determination unit 104 supplies the heat medium as measured by the heat medium flow meter 65. However, the reference value of the amount of heat medium stored in the storage unit 102 (the second reference value when the reference value used for the determination process is one, and the upper limit when the reference value used for the determination process is two). It is determined whether there is a magnitude relationship with respect to the medium amount).
Further, when the water content obtained by the water content acquisition unit 101 is smaller than the reference water content, the heat medium amount determination unit 104 determines that the heat medium supply amount measured by the heat medium flow meter 65 is determined. Reference value of heat medium amount stored in storage unit 102 (second reference value when there is one reference value used for determination processing, lower limit heat medium when there are two reference values used for determination processing) It is determined whether there is a magnitude relationship with respect to the quantity).

The heat medium control unit 105 controls the supply amount of the heat medium for heating the sludge of the heat dehydrator according to the determination result of the heat medium amount determination unit 104. The target controlled by the heat medium control unit 105 is, for example, the heat medium supply pump 60. The heat medium control unit 105 controls the heat medium supply pump 60 to increase or decrease the amount of the heat medium (hot water H) supplied to the heat dehydrator 50 by controlling the on / off control or the rotation speed.

For example, in the determination result of the moisture content determination unit 103, the heat medium control unit 105 is the first when the moisture content obtained by the moisture content acquisition unit 101 is a reference value (when the reference value used for the determination process is one). If the reference value and the reference value used for the judgment process are higher than the upper limit moisture content) and less than the upper limit heat medium amount, the heat medium supply is increased and the moisture content is increased. The water content obtained by the acquisition unit 101 is the reference value (the first reference value when there is one reference value used in the determination process, and the lower limit moisture content when there are two reference values used in the determination process). If it is lower than the lower limit heat medium amount and is equal to or higher than the lower limit heat medium amount, the heat medium supply is reduced.

Here, the heat medium control unit 105 may control the temperature of the heating unit 50A4 instead of controlling the amount of the heat medium supplied to the heating / dehydrating machine 50. For example, a temperature sensor for detecting the temperature of the heat medium in the heating unit 50A4 is provided in the second space 50A2, and the temperature is raised or lowered so that the temperature becomes a reference value based on the detection result of the temperature sensor. As described above, the drive amount of the heat medium supply pump 60 may be controlled.

The coagulant determination unit 106 determines which of the magnitude relations the supply amount of the coagulant measured by the coagulant flow meter 45 has with respect to the reference value of the supply amount of the inorganic coagulant stored in the storage unit 102. judge.
Specifically, when the water content obtained by the water content acquisition unit 101 is larger than the reference dehydration rate, the coagulant determination unit 106 supplies the inorganic coagulant as measured by the coagulant flow meter 45. However, when the reference value of the supply amount of the inorganic flocculant stored in the storage unit 102 (the third reference value when the reference value used for the determination process is one, and the reference value used for the determination process is two). It is determined which of the magnitude relations with respect to the upper limit coagulant amount).
Further, in the coagulant determination unit 106, when the water content obtained by the water content acquisition unit 101 is smaller than the reference dehydration rate, the supply amount of the inorganic coagulant measured by the coagulant flow meter 45 is determined. Reference value of the supply amount of the inorganic flocculant stored in the storage unit 102 (the third reference value when the reference value used for the determination process is one, and the reference value used for the determination process when there are two). It is determined whether there is a magnitude relationship with respect to the lower limit coagulant amount).

The coagulant control unit 107 controls the supply amount of the inorganic coagulant according to the determination result of the coagulant determination unit 106. The object controlled by the coagulant control unit 107 is, for example, the coagulant supply pump 40. The coagulant control unit 107 controls the coagulant supply pump 40 to increase or decrease the amount of the inorganic coagulant supplied to the concentrated sludge D by controlling the on / off control or the rotation speed.

For example, in the determination result of the water content determination unit 103, the coagulant control unit 107 has the water content obtained by the water content acquisition unit 101 as a reference value (when the reference value used for the determination process is one, the first If the reference value and the reference value used for the judgment process are two or more, the supply of the heat medium is predetermined (the second reference value when the reference value used for the judgment is one). , When the reference value used for the determination is two, the upper limit heat medium amount is increased), the coagulant supply pump 40 increases (or starts supplying) the supply amount of the inorganic coagulant.
In the determination result of the water content determination unit 103, the coagulant control unit 107 determines that the water content obtained by the water content acquisition unit 101 is a predetermined value (when the determination value is one, the first reference value is determined). When the reference value used for is two, it is less than or equal to the lower limit water content), and the supply amount of the flocculant is predetermined (when the reference value used for the determination is one, the third reference value is used for the determination). When the reference value is two or more, the lower limit coagulant amount) or more, the supply amount of the inorganic coagulant supplied by the coagulant supply pump 40 is reduced (or stopped).

The press-fitting pressure determination unit 108 determines whether the press-fitting pressure measured by the press-fitting pressure sensor 48 has a magnitude relationship with the reference value of the press-fitting pressure stored in the storage unit 102.
Specifically, when the water content obtained by the water content acquisition unit 101 is larger than the reference dehydration rate, the press-fit pressure determination unit 108 stores the press-fit pressure measured by the press-fit pressure sensor 48 in the storage unit 102. With respect to the reference value of the press-fitting pressure stored in (the fourth reference value when the reference value used for the determination process is one, and the upper limit press-fitting pressure when the reference value used for the determination process is two). Determine which of the magnitude relationships.
Further, when the water content obtained by the water content acquisition unit 101 is smaller than the reference dehydration rate, the press-fit pressure determination unit 108 stores the press-fit pressure measured by the press-fit pressure sensor 48 in the storage unit 102. Greater or lesser relationship with the reference value of the press-fitting pressure (the fourth reference value when there is one reference value used for the judgment process, and the lower limit press-fitting pressure when there are two reference values used for the judgment process). Which of the above is determined.

The press-fitting pressure control unit 109 controls the press-fitting pressure according to the determination result of the press-fitting pressure determination unit 108. The object controlled by the press-fitting pressure control unit 109 is, for example, the ribbon screw 50d. In the heating dehydrator, the rotation speed of the ribbon screw 50d is controlled so that the press-fitting pressure measured by the press-fitting pressure sensor 48 becomes a preset press-fitting pressure. If the measured press-fitting pressure is lower than the set press-fitting pressure, the rotation speed of the ribbon screw 50d is decreased, and if the measured press-fitting pressure is higher than the set press-fitting pressure, the rotation speed of the ribbon screw 50d is increased. I'm letting you. The higher the press-fitting pressure setting value, the more the amount of sludge solids leaking from the filtration screen 50B increases, while the number of rotations of the ribbon screw 50d decreases, so the sludge retention time in the dehydrator increases and the water content decreases. To do. The press-fitting pressure control unit 109 controls the rotation speed of the ribbon screw 50d by controlling the rotation speed of the rotation drive unit 50c. The lower the rotation speed of the ribbon screw 50d, the higher the press-fitting pressure, and the higher the rotation speed of the ribbon screw 50d, the lower the press-fitting pressure.

The back pressure determination unit 110 determines which of the magnitude relations the back pressure opening degree obtained from the back pressure sensor 50Gs has with respect to the reference value of the back pressure opening degree stored in the storage unit 102.
Specifically, when the water content obtained by the water content acquisition unit 101 is larger than the reference dehydration rate, the back pressure determination unit 110 stores the back pressure opening degree measured by the back pressure sensor 50 Gs. The reference value of the back pressure stored in the unit 102 (the fifth reference value when the reference value used for the determination process is one, and the upper limit back pressure when the reference value used for the determination process is two). On the other hand, it is determined whether the relationship is large or small.
Further, in the back pressure determination unit 110, when the water content obtained by the water content acquisition unit 101 is smaller than the reference dehydration rate, the back pressure opening degree measured by the back pressure sensor 50 Gs is stored in the storage unit 102. With respect to the reference value of the back pressure stored in (the fifth reference value when the reference value used for the determination process is one, and the lower limit back pressure when the reference value used for the determination process is two). Determine which of the magnitude relationships.

The back pressure control unit 111 controls the back pressure according to the measurement result of the back pressure determination unit 110. The target controlled by the back pressure control unit 111 is, for example, the back pressure plate 50G (back pressure plate drive unit). The back pressure control unit 111 drives the back pressure plate drive unit to move the back pressure plate 50G in any direction along the axial direction. As a result, the degree of opening of the discharge port 50F is increased or decreased.

The control unit 112 controls each unit in the control panel 100 according to a control program for controlling each unit of the heat dehydration system 1.
The communication unit 113 communicates with each unit of the heating / dehydrating system 1.

Next, the operation of the heat dehydration system 1 in the above-described embodiment will be described.
FIG. 3 is a flowchart illustrating the operation of the heat dehydration system 1.
The aggregating device 10 mixes the organic sludge A supplied from the outside and the polymer flocculant B and supplies the coagulating sludge C to the concentrating device 20. The concentrating device 20 concentrates the coagulated sludge C, and supplies the concentrated sludge C as the concentrated sludge D to the heating / dehydrating machine 50. Here, when the inorganic coagulant is supplied from the coagulant supply pump 40, the inorganic coagulant is injected into the concentrated sludge D and then supplied to the heat dehydrator 50. The coagulant flow meter 45 measures the supply amount of the inorganic coagulant supplied from the coagulant supply pump 40, and outputs the measurement result to the control panel 100. The heat medium supply pump 60 supplies hot water H to the second space 50A2 of the heating / dehydrating machine 50. The heat dehydrator 50 dehydrates the supplied concentrated sludge D (step S100). Here, since the hot water H is supplied to the second space 50A2, the concentrated sludge D is heated by the heating unit 50A4 using the hot water H as a heat medium, so that the water can be easily separated from the concentrated sludge D. , The concentrated sludge D can be efficiently dehydrated.
The concentrated sludge D is dehydrated by the heating / dehydrating machine 50, and then supplied to the incineration facility 80 by the dehydrating sludge pump 70 as the dehydrated sludge I and incinerated.
The water content meter 75 measures the water content of the dehydrated sludge I and outputs the measurement result to the control panel 100.

The water content determination unit 103 of the control panel 100 determines whether or not the water content obtained from the water content meter 75 is equal to or higher than the upper limit water content (step S101).
The control unit 112 proceeds to step S102 when the determination result of the water content determination unit 103 is equal to or higher than the upper limit moisture content (step S101-YES), and when the determination result is not equal to or higher than the upper limit moisture content (step S101-NO). Goes to step S111.
In step S102, the control unit 112 waits until a predetermined timer time elapses. When the predetermined timer time elapses, the control unit 112 instructs the press-fitting pressure determination unit 108 to execute the determination process. Upon receiving the determination processing instruction from the control unit 112, the press-fitting pressure determination unit 108 acquires the measurement result of the press-fitting pressure from the press-fitting pressure sensor 48 and determines whether or not it is less than the upper limit press-fitting pressure (step S103).

The press-fitting pressure control unit 109 increases the press-fitting pressure when it is less than the upper limit press-fitting pressure in the determination result of the press-fitting pressure determining unit 108 (step S103-YES). For example, the press-fitting pressure determination unit 108 reduces the rotation speed of the ribbon screw 50d by increasing the press-fitting pressure by one step. The amount of increase in the press-fitting pressure is set in advance in multiple stages, for example. Therefore, the press-fitting pressure determination unit 108 instructs the rotation drive unit 50c to increase or decrease the rotation speed so that the measured press-fitting pressure becomes the set press-fitting pressure. As a result, the rotation speed of the ribbon screw 50d decreases, so that the pressure in the first space 50A1 increases.
After that, the control unit 112 shifts the process to step S100.

The control unit 112 instructs the back pressure determination unit 110 to execute the determination process when the pressure is not less than the upper limit press-fitting pressure (step S103-NO), that is, when the pressure is equal to or higher than the upper limit press-fitting pressure. When the back pressure determination unit 110 receives the instruction of the determination process from the control unit 112, the back pressure determination unit 110 acquires the measurement result of the back pressure from the back pressure sensor 50Gs and determines whether or not it is less than the upper limit back pressure (step S105).
When the back pressure is less than the upper limit back pressure (step S105-YES), the back pressure control unit 111 controls to close the back pressure plate (step S106). For example, the back pressure control unit 111 lowers the opening degree of the back pressure plate by one step. For example, the back pressure control unit 111 controls to close (make the discharge port 50F smaller) or open (so that the discharge port 50F becomes larger) according to a plurality of preset openings. Can be done. Therefore, the back pressure control unit 111 controls the back pressure plate 50G so that the opening degree is one step lower than the current step. As a result, the pressure in the first space 50A1 increases, which promotes the separation of the water content of the concentrated sludge D in the first space 50A1.
After that, the control unit 112 shifts the process to step S100.

When the control unit 112 is not less than the upper limit back pressure (step S105-NO), that is, when it is equal to or more than the upper limit back pressure, the control unit 112 instructs the heat medium amount determination unit 104 to execute the determination process. .. Upon receiving the determination processing instruction from the control unit 112, the heat medium amount determination unit 104 determines whether or not the supply amount of the heat medium obtained from the heat medium flow meter 65 is less than the upper limit heat medium amount (step S107). ).
When the heat medium control unit 105 is less than the upper limit heat medium amount (step S107-YES), the heat medium control unit 105 controls to increase the heat medium (step S108). For example, the heat medium control unit 105 controls the heat medium supply pump 60 to increase the supply amount of hot water H supplied from the heat medium supply pump 60 to the heat dehydrator 50. For example, the heat medium control unit 105 raises the supply amount of hot water H from the heat medium supply pump 60 by one step. The amount of increase is set in advance in multiple stages, for example, and the heat medium supply pump 60 is instructed to drive the one having a supply amount larger than the current stage with the supply amount one stage higher. As a result, the supply amount of the hot water H supplied from the heat medium supply pump 60 increases, so that the degree of heating of the concentrated sludge D in the first space 50A1 increases. As a result, the temperature of the concentrated sludge D rises, and the separation of water is promoted.
After that, the control unit 112 shifts the process to step S100.

The control unit 112 instructs the coagulant determination unit 106 to execute the determination process when the amount is not less than the upper limit heat medium amount (step S107-NO), that is, when the amount is equal to or more than the upper limit heat medium amount. Upon receiving the determination processing instruction from the control unit 112, the coagulant determination unit 106 acquires the measurement result of the supply amount of the inorganic coagulant from the coagulant flow meter 45, and the amount is less than the upper limit coagulant amount of the coagulant supply amount. It is determined whether or not there is (step S109).

When the supply amount of the coagulant is less than the upper limit coagulant amount (step S109-YES), the coagulant control unit 107 controls to increase the supply amount of the coagulant (step S110). For example, the coagulant control unit 107 raises the supply amount of the coagulant by one step. For example, the coagulant control unit 107 controls the coagulant supply pump 40 so that the supply amount is one step higher than the current step among the plurality of preset steps of the supply amount. As a result, the amount of the inorganic coagulant injected into the concentrated sludge D increases, so that the heat dehydrator 50 can be supplied in a state where the ratio of the inorganic coagulant to the concentrated sludge D is increased. As a result, the inorganic flocculant is increased, and heating with warm water H promotes the separation of water in the concentrated sludge D in the first space 50A1.
After that, the control unit 112 shifts the process to step S100.

On the other hand, in step S101, when it is determined that the water content is not equal to or higher than the upper limit water content (step S101-NO), that is, when it is determined that the water content is less than the upper limit water content, the water content determination unit 103 starts from the water content meter 75. It is determined whether or not the obtained water content is equal to or less than the lower limit water content (step S111). If it is not less than or equal to the lower limit water content (step S111-NO), the control unit 112 shifts the process to step S100.
On the other hand, when the control unit 112 is equal to or less than the lower limit water content (step S111-YES), the control unit 112 waits in step S112 until a predetermined timer time elapses. When the predetermined timer time elapses, the control unit 112 instructs the coagulant determination unit 106 to execute the determination process. Upon receiving the determination processing instruction from the control unit 112, the coagulant determination unit 106 acquires the measurement result of the supply amount of the inorganic coagulant from the coagulant flow meter 45, and the measurement result is the lower limit coagulant of the supply amount of the coagulant. It is determined whether or not the amount is equal to or greater than the amount (step S113).

The coagulant control unit 107 reduces the coagulant supply amount when the coagulant supply amount is equal to or greater than the lower limit coagulant amount (step S113-YES). For example, the coagulant control unit 107 reduces the supply amount of the coagulant by one step (step S114). For example, the coagulant control unit 107 controls the coagulant supply pump 40 so that the supply amount is one step lower than the current step among the plurality of preset steps of the supply amount. As a result, the amount of the inorganic flocculant injected into the concentrated sludge D is reduced, so that the heat dehydrator 50 can be supplied in a state where the ratio of the inorganic flocculant to the concentrated sludge D is reduced. As a result, the separation of water in the concentrated sludge D in the first space 50A1 is suppressed as the amount of the inorganic flocculant is reduced.
After that, the control unit 112 shifts the process to step S100.

When the supply amount of the coagulant is not equal to or more than the lower limit coagulant amount (step S113-NO), that is, when it is less than the lower limit coagulant amount, the control unit 112 causes the heat medium amount determination unit 104 to execute the determination process. Give instructions. Upon receiving the determination processing instruction from the control unit 112, the heat medium amount determination unit 104 determines whether or not the supply amount of the heat medium obtained from the heat medium flow meter 65 is equal to or greater than the lower limit heat medium amount (step S115). ).

When the heat medium control unit 105 is equal to or greater than the lower limit heat medium amount (step S115-YES), the heat medium control unit 105 controls to reduce the heat medium (step S116). For example, the heat medium control unit 105 lowers the supply amount of hot water H supplied from the heat medium supply pump 60 by one step. As a result, the supply amount of the hot water H supplied from the heat medium supply pump 60 decreases, so that the degree of heating of the concentrated sludge D in the first space 50A1 decreases. As a result, the temperature of the concentrated sludge D is lowered, and the separation of water is suppressed.
After that, the control unit 112 shifts the process to step S100.

On the other hand, when it is not equal to or more than the lower limit heat medium amount (step S115-NO), that is, when it is less than the lower limit heat medium amount, the control unit 112 instructs the back pressure determination unit 110 to execute the determination process. When the back pressure determination unit 110 receives the instruction of the determination process from the control unit 112, the back pressure determination unit 110 acquires the measurement result of the back pressure from the back pressure sensor 50Gs and determines whether or not it is equal to or higher than the lower limit back pressure (step S117).

The back pressure control unit 111 controls to open the back pressure plate when the back pressure is equal to or higher than the lower limit back pressure (step S117-YES) (step S118). For example, the back pressure control unit 111 raises the opening degree of the back pressure plate by one step. As a result, the discharge port 50F is opened so as to be large. As a result, the pressure in the first space 50A1 is reduced, so that the separation of water in the concentrated sludge D in the first space 50A1 is suppressed.
After that, the control unit 112 shifts the process to step S100.

When the back pressure is not equal to or higher than the lower limit back pressure (step S117-NO), that is, when the back pressure is less than the lower limit back pressure, the control unit 112 instructs the press-fitting pressure determination unit 108 to execute the determination process. do. Upon receiving the determination processing instruction from the control unit 112, the press-fitting pressure determination unit 108 acquires the measurement result of the press-fitting pressure from the press-fitting pressure sensor 48 and determines whether or not it is equal to or higher than the lower limit press-fitting pressure (step S119).

When the press-fitting pressure determination unit 108 is equal to or higher than the lower limit press-fitting pressure (step S119-YES), the press-fitting pressure is reduced. For example, the press-fitting pressure determination unit 108 lowers the press-fitting pressure by one step. As a result, the rotation speed of the ribbon screw 50d increases, so that the pressure in the first space 50A1 decreases. Therefore, the separation of water in the concentrated sludge D in the first space 50A1 is suppressed.
After that, the control unit 112 shifts the process to step S100.

According to the above-described embodiment, the water content of the dehydrated sludge I discharged from the heat dehydrator 50 becomes the target value while the hot water H is supplied into the heat dehydrator 50 as a heat medium and the concentrated sludge D is heated. I tried to control the amount of heat medium. As a result, the water content can be adjusted by adjusting the degree of heating by the heat medium, so that the degree of freedom in adjusting the water content is increased, and it becomes easy to adjust to the set water content. As a result, fluctuations in the water content of sludge discharged from the dehydrator can be suppressed.

Further, according to the present embodiment, when the current water content is higher than the target water content, the water content is adjusted by increasing the press-fitting pressure and the back pressure, and still reaches the target water content. If it could not be lowered, the amount of heat medium was increased. As a result, the water content can be controlled while suppressing the amount of heat medium used, as compared with the case where the water content is controlled by increasing the heat medium amount before the press-fitting pressure or back pressure is increased. Can be done. As a result, the amount of heat medium used can be reduced and used for another heat utilization facility.
In addition, if the target water content could not be reduced even if the heat medium amount was increased, an inorganic coagulant was added, so that the amount of the inorganic coagulant used was reduced and the water content was reduced. Rate control is possible. By reducing the amount of the inorganic flocculant used, the cost of the inorganic flocculant can be suppressed.

Further, according to the present embodiment, among the parameters to be adjusted, the adjustment is made from the injection amount of the flocculant which has a great influence on the running cost. If the current moisture content is lower than the target moisture content, reduce the injection amount of coagulant, and if the current moisture content is higher than the target moisture content, other parameters press-fitting pressure, back pressure plate Adjust the opening degree and the flow rate of the heat medium, and increase the injection amount of the coagulant when the target water content is still not reached.
According to the present invention, since the incineration facility can always be operated near the autoignition temperature, the auxiliary fuel can be significantly reduced and wasteful dehydration is not performed. That is, it is possible to always perform self-combustion operation with the minimum required amount of coagulant injected.

For example, conventionally, there is also a dehydration system in which an incineration facility is provided after the screw press. In such a case, if dehydrated sludge with a moisture content higher than the self-burning point is put into the incineration facility as a result of not being able to adjust to the set moisture content, auxiliary fuel is injected in the incineration facility to incinerate the dehydrated sludge. There is a need to. On the other hand, when dewatered sludge with a water content lower than the autoignition temperature is put into the incinerator, it is necessary to sprinkle water in the incinerator to lower the internal temperature of the incinerator, and the dewatering is wasted. It will end up being.
On the other hand, according to the above-described embodiment, the use of auxiliary fuel can be reduced and unnecessary dehydration can be avoided.

Further, when the water content is lower than the target even if the supply amount of the inorganic flocculant is reduced, the amount of heat medium supplied to the heat dehydrator 50 as hot water H is reduced. As a result, even when the water content is lower than the target water content, the water content can be controlled by adjusting the heat medium amount, so that the degree of freedom in adjusting the water content is increased and it is easy to adjust to the set water content. become. As a result, fluctuations in the water content of sludge discharged from the dehydrator can be suppressed.
In addition, the amount of heat medium used can be reduced and used for another heat utilization facility.
Further, even if the inorganic flocculant is adjusted and the heat medium amount is adjusted, when the water content is lower than the target water content, the water content is adjusted by lowering the back pressure and the press-fitting pressure. be able to. As a result, it is possible to give priority to controlling the water content by adjusting the supply amount of the inorganic flocculant and controlling the water content by adjusting the heat medium amount. Therefore, when controlling the water content, the operating cost of the heating dehydrator Or, the recovery of waste heat can be minimized.

Further, since the degree of heating of the concentrated sludge D is controlled according to the water content of the dehydrated sludge I, fluctuations in the water content of the dehydrated sludge I can be suppressed, and the dehydrated sludge I can be stably self-burned. Can be maintained at a point. Further, since the control of supplying the inorganic flocculant is also performed, the dehydrated sludge I can be more stably maintained at the autoignition point.
Further, according to the present embodiment, since the dehydrated sludge I can be stably operated so as to be near the autoignition temperature, it is possible to reduce the use of auxiliary fuel and burn it in the incineration facility at the subsequent stage.

Further, in the above-described embodiment, in controlling the water content, the adjustment by the press-fitting pressure, the adjustment by the back pressure, the adjustment by the amount of heat medium, and the adjustment by the input amount of the inorganic flocculant are performed in a predetermined order. , If there is a discrepancy between the measured moisture content and the moisture content set as the target, increase the amount of each change, or multiple parameters (press-fit pressure, back pressure, heat medium amount, inorganic aggregation). Agents) may be changed simultaneously (parallel).

Further, according to the above-described embodiment, the case where the concentrated sludge D is heated by supplying the hot water H to the second space 50A2 has been described, but if the concentrated sludge D can be heated, the heating dehydrator 50 can be used. The concentrated sludge D in the stage before being supplied may be heated. For example, hot water H is added to the concentrated sludge D in the path between the concentrator 20 and the heating / dehydrating machine 50, and the piping of the path between the concentrating device 20 and the heating / dehydrating machine 50 is heated by the hot water H. It may be.

When the filtration screen 50B is heated by adding warm water H to the filtrate as in the above-described embodiment, the amount of heat required to heat the concentrated sludge D can be suppressed. For example, when the organic sludge A is heated, the organic sludge A before being supplied to the concentrating device 20 has a larger amount of water than the concentrated sludge D concentrated in the concentrating device 20, so that the amount of water is increased accordingly. This is because a large amount of heat is required.

Further, in the above-described embodiment, the flowchart of FIG. 3 includes a step of controlling the screw rotation speed (increasing or decreasing the rotation speed) according to the magnitude relationship of the current water content with respect to the reference value of the water content. You may try to do it.
Further, in the above-described embodiment, in the flowchart of FIG. 3, the supply amount of the polymer flocculant is controlled (increased or decreased) according to the magnitude relationship of the current water content with respect to the reference value of the water content. It may include steps.

The control panel 100 in the above-described embodiment may be realized by a computer. In that case, the program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. Further, a "computer-readable recording medium" is a communication line for transmitting a program via a network such as the Internet or a communication line such as a telephone line, and dynamically holds the program for a short period of time. It may also include a program that holds a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or a client in that case. Further, the above program may be for realizing a part of the above-mentioned functions, and may be further realized for realizing the above-mentioned functions in combination with a program already recorded in the computer system. It may be realized by using a programmable logic device such as FPGA (Field Programmable Gate Array).

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and the design and the like within a range not deviating from the gist of the present invention are also included.

1 ... Heat dehydration system, 2a ... Concentration filtration screen, 10 ... Coagulator, 20 ... Concentrator, 30 ... Concentrated sludge supply pump, 40 ... Coagulant supply pump, 45 ... Coagulant flow meter, 48 ... Press-fit pressure sensor, 50 ... heating dehydrator, 50A ... casing, 50A1 ... first space, 50A2 ... second space, 50A3 ... third space, 50A4 ... heating unit, 50B ... filtration screen, 50Ba ... inner filtration screen, 50Bb ... outer filtration Screen, 50c ... Rotary drive unit, 50C ... Board, 50d ... Ribbon screw, 50D ... Lid, 50e ... Connecting plate, 50E ... Discharge chamber, 50f ... Supply pipe, 50F ... Discharge port, 50G ... Back pressure plate, 50Gs ... Back Pressure sensor, 50H ... drainage pipe, 60 ... heat medium supply pump, 65 ... heat medium flow meter, 70 ... dehydration sludge pump, 75 ... moisture content meter, 80 ... incineration equipment, 81 ... incinerator, 82 ... boiler, 83 ... Smoke exhaust treatment tower, 100 ... control panel, 101 ... water content acquisition unit, 102 ... storage unit, 103 ... water content determination unit, 104 ... heat medium amount determination unit, 105 ... heat medium control unit, 106 ... coagulant determination unit , 107 ... coagulant control unit, 108 ... press-fitting pressure determination unit, 110 ... back pressure determination unit, 111 ... back pressure control unit, 112 ... control unit, 113 ... communication unit

In order to solve the above-mentioned problems, one aspect of the present invention is a heat dehydrator, a water content acquisition unit for acquiring the water content of sludge discharged from the heat dehydrator, and rotation of a screw of the heat dehydrator. A press-fitting pressure control unit that controls the press-fitting pressure by controlling the number, and a back pressure control unit that is provided at the discharge port of the heating / dehydrating machine and controls the degree of opening between the back pressure plate that presses the sludge and the discharge port. , depending on the water content, supplying supplies a heat medium control section for controlling the supply of heating medium for heating the sludge of the heating dehydrator, an aggregating agent to the sludge to be supplied to the heating dehydrator It has a coagulant control unit that controls the amount, and the press-fit pressure control unit increases the press-fit pressure by reducing the number of rotations of the screw when the water content is higher than the upper limit water content. When the water content is higher than the upper limit water content and the press-fitting pressure is equal to or higher than the upper limit press-fitting pressure, the back pressure control unit closes the back pressure plate so that the degree of opening becomes smaller, and the heat medium control unit When the water content is higher than the upper limit water content, the press-fitting pressure is equal to or higher than the upper limit press-fitting pressure, and the back pressure due to the back pressure plate is equal to or higher than the upper limit back pressure, the temperature of the heat medium is 50 ° C. or higher and 100 ° C. In the coagulant control unit, the water content is higher than the upper limit water content, the press-fitting pressure is equal to or higher than the upper limit press-fitting pressure, and the back pressure by the back pressure plate is the upper limit back pressure. When the pressure is equal to or higher than the pressure and the supply of the heat medium is equal to or higher than the upper limit heat medium amount, the supply of the coagulant is increased, and the coagulant control unit determines that the water content is lower than the lower limit water content. When the supply amount of the coagulant is reduced and the water content of the heat medium control unit is lower than the lower limit water content and the supply amount of the coagulant is less than the lower limit coagulant amount, the temperature of the heat medium is raised. The supply of the heat medium having a temperature of 50 ° C. or higher and lower than 100 ° C. is reduced, and the back pressure control unit has a water content lower than the lower limit water content, and the supply amount of the coagulant is less than the lower limit coagulant amount. When the amount of the heat medium is less than the lower limit heat medium amount, the back pressure plate is opened so that the degree of opening is large, and the press-fitting pressure control unit has the water content lower than the lower limit water content and the coagulant. When the supply amount of is less than the lower limit coagulant amount, the amount of the heat medium is less than the lower limit heat medium amount, and the pressure of the back pressure plate is less than the lower limit back pressure, the rotation speed of the screw is increased. It is a heating and dehydration system that reduces the press-fitting pressure .

Further, one aspect of the present invention is press-fitting by controlling a heat dehydrator, a water content acquisition unit for acquiring the water content of sludge discharged from the heat dehydrator, and a screw rotation speed of the heat dehydrator. A press-fitting pressure control unit that controls the pressure, a back pressure control unit that is provided at the discharge port of the heating / dehydrator and controls the degree of opening between the back pressure plate that presses the sludge and the discharge port, and a back pressure control unit according to the water content. , A heat medium control unit that controls the supply of a heat medium for heating the sludge of the heating dehydrator, and a coagulant control that controls a supply amount of a coagulant for the sludge supplied to the heating dehydrator. It is a heat dehydration method in a heat dehydration system having a unit, in which a water content acquisition unit acquires the water content of sludge discharged from the heat dehydrator, and the press-fitting pressure control unit obtains the water content up to the upper limit of the water content. When the rate is higher than the rate, the press-fitting pressure is increased by reducing the number of rotations of the screw, and the back pressure control unit has the water content higher than the upper limit water content and the press-fitting pressure is equal to or higher than the upper limit press-fitting pressure. If, the back pressure plate is closed so that the degree of opening is small, and the heat medium control unit has the water content higher than the upper limit water content, the press-fitting pressure is equal to or higher than the upper limit press-fitting pressure, and the back pressure plate. When the back pressure due to is equal to or higher than the upper limit back pressure, the supply of the heat medium having a temperature of 50 ° C. or higher and lower than 100 ° C. is increased, and the coagulant control unit causes the water content to exceed the upper limit water content. When the press-fitting pressure is equal to or higher than the upper limit press-fitting pressure, the back pressure by the back pressure plate is equal to or higher than the upper limit back pressure, and the supply of the heat medium is equal to or higher than the upper limit heat medium amount, the coagulant is supplied. The coagulant control unit reduces the supply amount of the coagulant when the water content is lower than the lower limit water content, and the heat medium control unit has the water content lower than the lower limit water content. When the supply amount of the coagulant is less than the lower limit coagulant amount, the supply of the heat medium whose temperature of the heat medium is 50 ° C. or higher and lower than 100 ° C. is reduced, and the back pressure control unit causes the water content. Is lower than the lower limit water content, the supply amount of the coagulant is less than the lower limit coagulant amount, and the amount of the heat medium is less than the lower limit heat medium amount, the back pressure plate is arranged so that the degree of opening becomes large. When the press-fitting pressure control unit opens, the water content is lower than the lower limit water content, the supply amount of the coagulant is less than the lower limit coagulant amount, and the amount of the heat medium is less than the lower limit heat medium amount. This is a heating and dehydration method in which the press-fitting pressure is reduced by increasing the number of rotations of the screw when the pressure of the back pressure plate is less than the lower limit back pressure .

Claims (11)

With a heating dehydrator
A water content acquisition unit that acquires the water content of sludge discharged from the heating / dehydrating machine,
A heat medium control unit that controls the supply of a heat medium for heating the sludge of the heating / dehydrating machine according to the water content.
Heat dehydration system with. The heat dehydration system according to claim 1, wherein the heat medium control unit controls at least one of the amount of the heat medium and the temperature. The heating / dehydrating system according to claim 1 or 2, further comprising a heating portion that heats the sludge of the heating / dehydrating machine from the outer peripheral side of the accommodating portion using the heat medium. The heat medium control unit
When the water content is higher than the reference value, the supply of heat medium is increased.
The heat dehydration system according to any one of claims 1 to 3, wherein when the water content is lower than the reference value, the supply of the heat medium is reduced. It has a heat medium supply unit that supplies a heat medium heated by the heat obtained by burning the sludge discharged from the heat dehydration system.
The heat dehydration system according to any one of claims 1 to 4, wherein the heat medium control unit controls the amount of heat medium supplied from the heat medium supply unit. A coagulant supply unit that supplies a coagulant to the sludge supplied to the heat dehydrator,
When the water content is equal to or higher than a predetermined value and the supply of the heat medium is increased to a predetermined value, the coagulant control unit increases the supply of the coagulant by the coagulant supply unit.
The heat dehydration system according to any one of claims 1 to 5. The heat medium control unit
The heat dehydration system according to claim 6, wherein the supply of the heat medium is reduced when the water content is equal to or less than a predetermined value and the supply of the flocculant is reduced to a predetermined value. The heating / dehydrating system according to any one of claims 1 to 7, further comprising a dehydrating sludge pump that supplies sludge discharged from the heating / dehydrating machine to a subsequent incineration facility. The moisture content acquisition unit acquires the moisture content of the sludge discharged from the heat dehydrator,
A heating / dehydrating method in which the heat medium control unit controls the supply of a heat medium for heating the sludge of the heating / dehydrating machine according to the water content. A claim that the coagulant control unit increases the supply of the coagulant to the sludge supplied to the heat dehydrator when the water content is equal to or higher than a predetermined value and the supply of the heat medium is increased to a predetermined value. 9. The heat dehydration method according to 9. The heat dehydration method according to claim 10, wherein the heat medium control unit reduces the supply of the heat medium when the water content is equal to or less than a predetermined value and the supply of the flocculant is reduced to a predetermined level.

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