JP2017116196A - Sewage sludge drying system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage sludge drying system capable of curbing energy consumed for drying sewage sludge.SOLUTION: A sewage sludge drying system 1 dries sewage sludge in a drying chamber 2 with hot water circulated between a heat pump 4 and a hot water jacket 3. Gas containing moisture generated from the sewage sludge in the drying chamber 2 is circulated to a condenser 5 and a first heat exchanger 6 in this order and returned to the drying chamber 2. The condenser 5 condenses the gas through heat exchange between the gas and a coolant and discharges condensate water. The first heat exchanger 6 increases a temperature of the gas through the heat exchange between the gas and the hot water. Heat of the coolant transferred from the gas through the heat exchange therewith in the condenser 5 is recycled as a heat source of the heat pump 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sewage sludge drying system for drying sludge contained in sewage.

  In the sewage treatment facility, sewage is treated to produce treated water, and the treated water is returned to the natural environment. Here, the sewage after generating the treated water contains high clay and high water content sludge. Such sludge is recycled as a solid state by reducing the moisture content by drying. Patent Document 1 describes a sewage sludge drying system for drying sludge.

JP 2010-158616 A

  A large amount of energy is required to dry the sludge contained in the sewage. Here, from the viewpoint of economic consideration and environmental consideration, it is required to suppress energy consumed for drying sludge.

  The subject of this invention is providing the sewage sludge drying system which can suppress the energy consumed for drying of sludge in view of such a point.

  In order to solve the above-described problems, a sewage sludge drying system of the present invention includes a drying chamber into which sewage sludge is charged, a temperature tank for heating the drying chamber, a heat source side heat exchanger, and a use side. A heat pump including a heat exchanger, a condenser, a heat exchanger, a first fluid circulation path for returning fluid from the use side heat exchanger to the use side heat exchanger via the temperature bath, and the drying chamber A gas circulation path for returning the gas to the drying chamber through the condenser and the heat exchanger in this order, and the fluid from the first fluid circulation path to the first fluid via the heat exchanger. In order to use the second fluid circulation path returning to the circulation path, the refrigerant supply path that supplies the refrigerant to the condenser, and the heat of the refrigerant that has exchanged heat with the gas in the condenser as a heat source for the heat pump. Refrigerant heat And the condenser condenses the gas by heat exchange between the gas and the refrigerant to discharge condensed water, and the heat exchanger performs the heat exchange between the gas and the fluid. It is characterized by raising the temperature of the gas.

According to the present invention, the fluid is circulated between the temperature tank and the heat pump to heat the drying chamber and dry the sludge in the drying chamber. Since the temperature of the fluid for heating the drying chamber is increased using a heat pump, the energy utilization efficiency is high. Further, after the condensed water is discharged from the gas in the drying chamber via a condenser, the gas is returned to the drying chamber via a heat exchanger. That is, after reducing the moisture content of the gas in the condenser, the temperature of the gas is raised in the heat exchanger to increase the saturated water vapor content of the gas. Therefore, drying of sludge in the drying chamber can be promoted by circulating the gas through the gas circulation path. Here, in order to heat the gas which returns to a drying chamber, since the heat of the fluid which circulates between a temperature tank and a heat pump is utilized, the utilization efficiency of energy is high. Moreover, the refrigerant | coolant heat utilization mechanism which utilizes the heat | fever of the refrigerant | coolant which heat-exchanged with gas in the condenser as a heat source of a heat pump is provided. Therefore, the energy utilization efficiency is high. Furthermore, in this invention, the gas of the drying chamber into which sludge was thrown is circulated along a gas circulation path. Thereby, since gas is not discharged | emitted from a gas circulation path outside, the smell of sludge does not leak outside.

  In this invention, the said 2nd fluid circulation path shall return the said fluid of the said temperature tank to the said temperature tank via the said heat exchanger. If it does in this way, the temperature of the gas which returns to a drying chamber can be raised using the fluid temporarily stored by the temperature tank. Thereby, since the saturated water vapor amount of the gas returning to the drying chamber can be increased, drying of the sludge in the drying chamber can be promoted by the circulation of the gas.

  In the present invention, the second fluid circulation path is configured such that the fluid in the forward path of the first fluid circulation path from the use side heat exchanger toward the temperature tank passes through the heat exchanger and is It can return to the return path of the first fluid circulation path toward the use side heat exchanger. If it does in this way, the temperature of the gas which returns to a drying room using the fluid which flows through the 1st circulation way can be raised. Thereby, since the saturated water vapor amount of the gas returning to the drying chamber can be increased, drying of the sludge in the drying chamber can be promoted by the circulation of the gas. In addition, if the fluid whose temperature has decreased due to heat exchange with the gas in the heat exchanger is returned to the return path of the first fluid circulation path from the temperature tank to the use side heat exchanger, the temperature of the temperature tank for heating the drying chamber Will not drop.

  Next, another embodiment of the present invention includes a drying chamber into which sewage sludge is charged, a temperature tank for heating the drying chamber, a heat pump including a heat source side heat exchanger and a use side heat exchanger, , A condenser, a heat exchanger, a hot water supply path for supplying hot water having a predetermined temperature or higher from the outside to the temperature tank, a hot water heat exchanger installed in the middle of the hot water supply path, and the fluid The first fluid circulation path returning from the use side heat exchanger to the use side heat exchanger via the hot water heat exchanger, the gas in the drying chamber, and the condenser and the heat exchanger in this order. A gas circulation path that returns the fluid to the drying chamber, a second fluid circulation path that returns the fluid from the first fluid circulation path to the first fluid circulation path via the heat exchanger, and a refrigerant to the condenser. The refrigerant supply path to be supplied and the condenser A refrigerant heat utilization mechanism for utilizing the heat of the refrigerant that has exchanged heat with the gas as a heat source of the heat pump. The heat exchanger increases the temperature of the gas by heat exchange between the gas and the fluid, and the heat exchanger for hot water heats the heat between the hot water and the fluid. The temperature of the hot water is increased by replacement.

  According to this invention, while providing the warm water supply path which supplies warm water more than predetermined temperature to a temperature tank from the outside, the heat exchanger for warm water is installed in the warm water supply path. The fluid is circulated between the heat exchanger for hot water and the heat pump to raise the temperature of the hot water and supply it to the temperature tank, thereby heating the drying chamber and drying the sludge in the drying chamber. Since the temperature of the hot water having a predetermined temperature from the outside is raised using the liquid supplied from the heat pump and supplied to the temperature bath, the energy use efficiency is high. Further, after the condensed water is discharged from the gas in the drying chamber via a condenser, the gas is returned to the drying chamber via a heat exchanger. That is, after reducing the moisture content of the gas in the condenser, the temperature of the gas is raised in the heat exchanger to increase the saturated water vapor content of the gas. Therefore, drying of sludge in the drying chamber can be promoted by circulating the gas through the gas circulation path. Here, in order to heat the gas which returns to a drying chamber, since the heat of the fluid which circulates between a temperature tank and a heat pump is utilized, the utilization efficiency of energy is high. Moreover, the refrigerant | coolant heat utilization mechanism which utilizes the heat | fever of the refrigerant | coolant which heat-exchanged with gas in the capacitor | condenser as a heat source of a heat pump is provided. Therefore, the energy utilization efficiency is high. Furthermore, in this invention, the gas of the drying chamber into which sludge was thrown is circulated along a gas circulation path. Thereby, since gas is not discharged | emitted from a gas circulation path outside, the smell of sludge does not leak outside.

Here, a sewage treatment plant provided with a sewage sludge drying system is equipped with a hot water supply system for supplying hot water using digestion gas generated by the sludge digestion process in the digestion tank as fuel for combustion equipment such as a boiler. May have. In such a case, it is easy to procure hot water by using hot water from a hot water supply system as hot water from the outside. A sewage treatment plant provided with a sewage sludge drying system may be provided with a gas generator using digestion gas as fuel. In such a case, hot water heated to a predetermined temperature or higher using exhaust heat of the gas generator can be used as hot water from the outside.

  In this invention, the said refrigerant | coolant heat utilization mechanism can be made into the supply path which supplies the refrigerant | coolant heat-exchanged with the said gas in the said capacitor | condenser to the said heat source side heat exchanger. If it does in this way, the refrigerant which temperature rose by heat exchange with the gas in a capacitor can be directly supplied to the heat source side heat exchanger of a heat pump, and can be used as a heat source.

  In this invention, the said refrigerant | coolant heat utilization mechanism is a 2nd heat exchanger, and the said refrigerant | coolant by which heat exchange was performed between the said gas in the said capacitor | condenser is supplied to the said 2nd heat exchanger. A refrigerant supply path, and a fluid circulation path for circulating a second fluid between the heat source side heat exchanger and the second heat exchanger, wherein the second heat exchanger includes the refrigerant and The temperature of the second fluid can be increased by heat exchange with the second fluid. In this way, even when the refrigerant is not suitable for supply to the heat source side heat exchanger of the heat pump, the heat of the refrigerant whose temperature has increased due to heat exchange with the gas in the condenser is used in the heat pump. it can.

  In the present invention, the fluid supplied from the heat pump to the temperature vessel can be a liquid such as heated water.

  In the present invention, the fluid supplied from the heat pump to the temperature vessel can be a gas such as heated steam.

  In the present invention, the refrigerant may be sewage treated water. The temperature of sewage treated water that is generated by treating sewage and then released to rivers and the like is stable at around 20 ° C. throughout the year. Therefore, it can be used as a refrigerant for exchanging heat with the gas from the drying chamber. Moreover, if it is sewage treated water, it can be supplied to the heat source side heat exchanger of the heat pump after passing through the condenser. In addition, if it is sewage treated water, it can be discharged as it is into a river after being used as a refrigerant.

  According to the present invention, the sludge put into the drying chamber is dried by the heat of the fluid heated by the heat pump. Further, in order to heat the gas returning from the drying chamber to the drying chamber via the condenser and the heat exchanger, the heat of the fluid circulating between the temperature tank and the heat pump is used. Furthermore, a refrigerant heat utilization mechanism is provided that uses the heat of the refrigerant whose temperature has been raised by heat exchange with the gas in the condenser as a heat source for the heat pump. Therefore, the energy utilization efficiency is high. Further, according to the present invention, the gas in the drying chamber is discharged through the condenser and then the condensed water is discharged, and then returned to the drying chamber through the heat exchanger. Therefore, drying of sludge in the drying chamber can be promoted by circulating the gas through the gas circulation path. Furthermore, in this invention, the gas of the drying chamber into which sludge was thrown is circulated along a gas circulation path. Thereby, since gas is not discharged | emitted from a gas circulation path outside, the smell of sludge does not leak outside.

It is a schematic block diagram of the principal part of a sewage sludge drying system. It is a schematic block diagram of the principal part of the sewage sludge drying system of the modification 2. It is a schematic block diagram of the principal part of the sewage sludge drying system of the modification 3. It is a schematic block diagram of the principal part of the sewage sludge drying system of the modification 4. It is a schematic block diagram of the principal part of the sewage sludge drying system of the modification 5.

  Below, with reference to drawings, the sewage sludge drying system which is embodiment which applied this invention is demonstrated.

  The sewage sludge drying system 1 of this example dries the sewage sludge 100 to obtain a dried product. The moisture content of the sludge 100 carried into the sewage sludge drying system 1 is about 80%, and the moisture content of the dried product is 20% to 40%. As shown in FIG. 1, a sewage sludge drying system 1 includes a drying chamber 2 into which sludge 100 is charged, a hot water jacket (temperature bath) 3, a heat pump 4, a condenser 5, and a first heat exchanger (heat exchanger). ) 6, a second heat exchanger (second heat exchanger) 7, and a controller 8.

  The drying chamber 2 includes an inlet 2a for the sludge 100 and an open / close door 9 that seals the inlet 2a so that the inlet 2a can be opened and closed. Further, the drying chamber 2 includes a discharge port (not shown) for discharging the dried product. The discharge port is sealed by an open / close door (not shown) so as to be opened and closed. The drying chamber 2 is provided with a first gas temperature sensor 11 that detects the temperature of the gas in the drying chamber 2.

  The hot water jacket 3 is a hot water tank that temporarily stores the liquid supplied from the heat pump 4. The hot water jacket 3 surrounds the bottom wall portion and the side wall portion of the drying chamber 2 and warms the drying chamber 2 with the stored liquid. The heat pump 4 includes a heat source side heat exchanger 13, a use side heat exchanger 14, and a heat pump controller 15.

  Further, the sewage sludge drying system 1 includes a first liquid circulation path (first fluid circulation path) 17 that circulates liquid between the hot water jacket 3 and the use side heat exchanger 14 of the heat pump 4. A first pump 18 is disposed in the first liquid circulation path 17. The liquid is water that is heated in the heat pump 4.

  Furthermore, the sewage sludge drying system 1 is configured to circulate the gas in the drying chamber 2 through the condenser 5 and the first heat exchanger 6 in this order, and the liquid in the hot water jacket 3 to the first. A second liquid circulation path 22 circulated through the heat exchanger 6 and a drainage path 23 connected to the condenser 5 are provided. A blower fan 25 is disposed in the gas circulation path 21. The blower fan 25 generates an air flow that returns from the drying chamber 2 to the drying chamber 2 via the condenser 5 along the gas circulation path 21. A second pump 27 is disposed in the second liquid circulation path 22. The second pump 27 returns the liquid in the hot water jacket 3 to the hot water jacket 3 via the first heat exchanger 6.

  Further, the sewage sludge drying system 1 includes a refrigerant flow passage 29 that passes through the condenser 5 and the second heat exchanger 7. A portion upstream of the condenser 5 in the refrigerant flow passage 29 is a refrigerant supply path 30 for supplying the refrigerant to the condenser 5. The flow path portion between the condenser 5 and the second heat exchanger 7 in the refrigerant flow passage 29 supplies the second heat exchanger 7 with the refrigerant that has exchanged heat with the gas in the condenser 5. This is a refrigerant supply path. A third pump 31 for circulating the refrigerant along the refrigerant flow path 29 is disposed in the refrigerant supply path 30. Furthermore, the sewage sludge drying system 1 includes a fluid circulation path 32 that circulates the second fluid between the second heat exchanger 7 and the heat source side heat exchanger 13 of the heat pump 4. A fourth pump 33 for circulating the liquid along the fluid circulation path 32 is disposed in the fluid circulation path 32. In this example, the refrigerant is sewage treated water.

A second gas temperature sensor 35 that detects the temperature of the gas flowing through the downstream end portion is installed at the downstream end portion of the return path from the first heat exchanger 6 toward the drying chamber 2 in the gas circulation path 21. In the second liquid circulation path 22, a liquid temperature sensor 36 that detects the temperature of the liquid flowing in the forward path is installed on the forward path from the hot water jacket 3 to the first heat exchanger 6.

  Here, the first gas temperature sensor 11 and the second gas temperature sensor 35 are connected to the input side of the controller 8. The first pump 18, the blower fan 25, the second pump 27, the third pump 31, the fourth pump 33, and the heat pump 4 are connected to the output side of the controller 8. The liquid temperature sensor 36 is connected to the input side of the heat pump controller 15. The heat pump controller 15 controls the heat pump 4 based on the output from the liquid temperature sensor 36.

(Sewage sludge drying operation)
In the sewage sludge drying operation, the controller 8 drives the heat pump 4. Further, the controller 8 drives the first pump 18, the blower fan 25, the second pump 27, the third pump 31, and the fourth pump 33. When the heat pump 4 is driven, the fluid (hot water) heated by the heat pump 4 circulates between the hot water jacket 3 and the heat pump 4. The heat pump controller 15 drives and controls the heat pump 4 based on the output from the liquid temperature sensor 36, and distributes the hot water to the first liquid circulation path 17. When the warm water flows through the first liquid circulation path 17, the warm water is temporarily stored in the warm water jacket 3. Accordingly, the drying chamber 2 is heated by the hot water stored in the hot water jacket 3. Thereby, the drying chamber 2 is 80 degreeC or more.

  In this example, warm water having a temperature that allows the inside of the drying chamber 2 to be 80 ° C. or higher flows through the first liquid circulation path 17. That is, the heat pump controller 15 controls the drive of the heat pump 4 based on the output from the liquid temperature sensor 36, and the heat pump based on the control command from the controller 8 to which the output of the first gas temperature sensor 11 is input. 4 is driven and controlled. Thereby, the heat pump controller 15 adjusts the temperature of the hot water supplied from the heat pump 4 to the hot water jacket 3 to make the inside of the drying chamber 2 80 ° C. or higher.

  The gas in the drying chamber 2 returns to the drying chamber 2 through the condenser 5 and the first heat exchanger 6 in this order by driving of the blower fan 25 installed in the gas circulation path 21. A gas containing moisture evaporated from the sludge 100 flows from the drying chamber 2 to the condenser 5. The temperature of the gas from the drying chamber 2 toward the condenser 5 is about 80 °.

  In the condenser 5, heat exchange is performed between the gas from the drying chamber 2 and the refrigerant. In this example, the refrigerant is sewage treated water. Here, the temperature of the sewage treated water produced by treating the sewage is stable at around 20 ° C. Therefore, the gas is sufficiently cooled by heat exchange with the refrigerant. Thereby, the gas is condensed and condensed water is discharged from the condenser 5. Condensed water is discharged to a river or the like through the drainage channel 23.

  The gas whose temperature has decreased due to condensation goes to the first heat exchanger 6. The temperature of the gas output from the condenser 5 and supplied to the first heat exchanger 6 is reduced to around 60 °.

  In the first heat exchanger 6, heat exchange is performed between the gas and hot water supplied from the heat pump 4. Here, by passing through the first heat exchanger 6, the temperature of the gas rises to a temperature higher than 80 °.

That is, the controller 8 drives and controls the blower fan 25 based on the outputs from the first gas temperature sensor 11 and the second gas temperature sensor 35, thereby passing the first heat exchanger 6 in the gas circulation path 21. While adjusting the amount of gas (air volume) and drivingly controlling the second pump 27 based on the output from the liquid temperature sensor 36, hot water passing through the first heat exchanger 6 in the second liquid circulation path 22 is controlled. Adjust the amount (flow path). Further, these controls are repeatedly performed with feedback. Thereby, the amount of heat transferred from the hot water to the gas in the first heat exchanger 6 is controlled, and the temperature of the gas toward the drying chamber 2 (the temperature of the gas detected by the second gas temperature sensor 35) is The temperature of the gas in the drying chamber 2 (the temperature of the gas detected by the first gas temperature sensor 11) is set to be equal to or higher.

  As the gas temperature rises, the amount of saturated water vapor in the gas increases. Therefore, the gas introduced into the drying chamber 2 from the gas circulation path 21 (the gas returning to the drying chamber 2) has a high temperature and is in a dry state. Therefore, drying of the sludge 100 in the drying chamber 2 is promoted by circulating the gas through the gas circulation path 21.

  Note that the refrigerant used for heat exchange with the gas in the condenser 5 is supplied to the second heat exchanger 7. Then, heat exchange is performed between the refrigerant and the second liquid in the second heat exchanger 7. Here, the temperature of the refrigerant used for heat exchange with the gas in the condenser 5 is rising. Therefore, in the second heat exchanger 7, the second fluid can be heated by heat exchange between the refrigerant and the second fluid. (The heat of the refrigerant can be transferred to the second fluid). Further, the second fluid circulates between the second heat exchanger 7 and the heat source side heat exchanger 13 of the heat pump 4. Therefore, the heat transferred from the refrigerant to the second fluid is used as a heat source for the heat pump 4. Here, the heat pump controller 15 drives and controls the heat pump 4 based on the output from the liquid temperature sensor 36 so that the temperature of the hot water supplied to the hot water jacket 3 becomes 80 ° C. or higher.

(Function and effect)
In this example, the temperature of warm water (fluid) for heating the drying chamber 2 is increased using the heat pump 4. Further, in order to heat the gas that is condensed in the condenser 5 and returns to the drying chamber 2, the heat of the hot water (fluid) circulating between the hot water jacket 3 and the heat pump 4 is used. Furthermore, the heat of the refrigerant whose temperature has increased due to heat exchange with the gas in the condenser 5 is used as a heat source for the heat pump 4. Therefore, the energy utilization efficiency is high.

  In this example, the gas in the drying chamber 2 is returned to the drying chamber 2 via the first heat exchanger 6 after the condensed water is discharged via the condenser 5. That is, after reducing the moisture content of the gas in the condenser 5, the temperature of the gas is raised in the first heat exchanger 6 to increase the saturated water vapor content of the gas. Therefore, drying of the sludge 100 in the drying chamber 2 can be promoted by circulating the gas through the gas circulation path 21.

  Furthermore, in the present invention, the gas in the drying chamber 2 into which the sludge 100 is charged is circulated along the gas circulation path 21. Thereby, since gas is not discharge | released outside from the gas circulation path 21, the smell of the sludge 100 does not leak outside.

  Here, this example uses sewage treated water as a refrigerant. Since the sewage sludge drying system is often provided in a sewage treatment plant, in such a case, it is easy to procure the refrigerant.

(Modification 1)
In the sewage sludge drying system 1, the first gas temperature sensor 11 disposed in the drying chamber 2 can be a humidity sensor. In this case, the controller 8 drives and controls the blower fan 25 and the heat pump 4 based on the humidity sensor. That is, when it is detected based on the humidity sensor that the water vapor amount of the gas in the drying chamber 2 has approached the saturated water vapor amount, the controller 8 (heat pump controller 15) is configured to supply hot water supplied from the heat pump 4. The temperature is increased and the saturated water vapor amount of the gas in the drying chamber 2 is increased. Alternatively, the controller 8 drives and controls the second pump 27 to increase the rotation speed. As a result, the amount (flow path) of hot water passing through the first heat exchanger 6 in the second liquid circulation path 22 is increased, the temperature of the gas is increased, and the saturated water vapor amount of the gas toward the drying chamber 2 is increased. Let

(Modification 2)
FIG. 2 is a schematic block diagram of a sewage sludge drying system 1A of the second modification. In this example, a three-way valve 41 is provided in the first liquid circulation path 17 in the middle of the forward path from the use side heat exchanger 14 of the heat pump 4 to the hot water jacket 3. The second liquid circulation path 22 that returns the hot water supplied from the heat pump 4 from the first liquid circulation path 17 to the first liquid circulation path 17 via the first heat exchanger 6 is the first liquid in the three-way valve 41. The hot water flowing through the circulation path 17 is branched, and then returned to the return path of the first liquid circulation path 17 via the first heat exchanger 6. That is, the second liquid circulation path 22 passes through the first heat exchanger 6 after warm water branched from the upstream side of the warm water jacket 3 in the first liquid circulation path 17, and then in the first liquid circulation path 17. Return to the downstream side of the hot water jacket 3.

  Here, the three-way valve 41 is connected to the output side of the controller 8. The three-way valve 41 is driven and controlled by the controller 8 based on the output from the second gas temperature sensor 35 installed at the downstream end portion of the return path from the first heat exchanger 6 toward the drying chamber 2 in the gas circulation path 21. The That is, the controller 8 controls the driving of the blower fan 25 based on the output from the second gas temperature sensor 35, thereby reducing the amount of gas (air volume) passing through the first heat exchanger 6 in the gas circulation path 21. The amount of hot water passing through the first heat exchanger 6 (flow path) in the second liquid circulation path 22 is controlled by adjusting and drivingly controlling the three-way valve 41 based on the output from the second gas temperature sensor 35. adjust. Further, these controls are repeatedly performed with feedback. Thus, the amount of heat transferred from the hot water to the gas in the first heat exchanger 6 is controlled, and the temperature of the gas toward the drying chamber 2 is set to a predetermined temperature.

  Also in this example, the same effect as the above example can be obtained. Further, in this example, the fluid whose temperature has decreased due to heat exchange with the gas in the first heat exchanger 6 is returned to the return path of the first liquid circulation path 17 from the hot water jacket 3 toward the use side heat exchanger 14, The temperature of the hot water jacket 3 that warms the drying chamber 2 does not decrease.

  Instead of the three-way valve 41, a pump that branches the first liquid circulation path 17 and pumps the liquid flowing through the first liquid circulation path 17 to the first heat exchanger 6 may be disposed.

(Modification 3)
FIG. 3 is a schematic block diagram of a sewage sludge drying system according to the third modification. The sewage sludge drying system 1 </ b> B in the third modification is obtained by omitting the second heat exchanger 7 in the sewage sludge drying system 1. In this example, as a refrigerant heat utilization mechanism for utilizing the heat of the refrigerant in the heat pump 4, a refrigerant flow path (supply path) 45 that passes from the condenser 5 through the heat pump 4 is provided. That is, in the sewage sludge drying system 1 </ b> B, the refrigerant that has exchanged heat with the gas in the condenser 5 is supplied directly to the heat source side heat exchanger 13 of the heat pump 4 through the refrigerant flow path 45. In this way, the heat of the refrigerant whose temperature has risen through the condenser 5 can be efficiently used as a heat source for the heat pump 4.

(Modification 4)
FIG. 4 is a schematic block diagram of a sewage sludge drying system of Modification 4. The sewage sludge drying system 1C of Modification 4 uses hot water supplied from an external hot water supply system. That is, in the sewage treatment plant where the sewage sludge drying system 1C is provided, there is a hot water supply system 51 that supplies hot water using digestion gas generated by the digestion process of the sludge 100 in the digester as fuel for combustion equipment such as a boiler. There is a case. In such a case, a warm water flow passage 52 through which the warm water supplied from the warm water supply system 51 is circulated via the warm water jacket 3 may be provided alongside the first liquid circulation path 17. In this case, the inside of the hot water jacket 3 is partitioned into a temperature bath portion 53 that functions as the first liquid circulation path 17 and a temperature bath portion 54 through which the hot water supplied from the hot water supply system 51 flows. Can do. In addition, a gas generator using digestion gas as fuel may be provided in a sewage treatment plant where the sewage sludge drying system 1C is provided. In such a case, hot water heated to a predetermined temperature or higher using exhaust heat of the gas generator can be used as hot water from the outside. That is, warm water heated to a predetermined temperature or higher by using exhaust heat of the gas generator can be introduced into the warm water flow passage 52 of the sewage sludge drying system 1C.

(Modification 5)
FIG. 5 is a schematic block diagram of a sewage sludge drying system of Modification 5. The sewage sludge drying system 1D of Modification 5 is a modification of the sewage sludge drying system 1A. The sewage sludge drying system 1D uses hot water from a hot water supply system 51 provided in the sewage treatment plant at the sewage treatment plant. Since the sewage sludge drying system 1D of this example has a configuration corresponding to that of the sewage sludge drying system 1A, the corresponding components are denoted by the same reference numerals and description thereof is omitted.

  The sewage sludge drying system 1 </ b> D of the present example includes a hot water supply path 61 that supplies external hot water having a predetermined temperature or higher supplied from an external hot water supply system 51 to the hot water jacket 3. The temperature of the hot water supplied from the external hot water supply system 51 is, for example, 40 ° C. or higher. A hot water heat exchanger 62 is provided in the middle of the hot water supply path 61.

  In the sewage sludge drying system 1D of this example, the first liquid circulation path 17 that circulates hot water between the use-side heat exchanger 14 of the heat pump 4 and the hot water jacket 3 in the sewage sludge drying system 1A is: The hot water (liquid) is circulated between the use side heat exchanger 14 of the heat pump 4 and the hot water heat exchanger 62. The second liquid circulation path 22 branches the hot water flowing through the first liquid circulation path 17 from the three-way valve 41 provided in the first liquid circulation path 17, and passes through the first heat exchanger 6 to cause the first liquid to flow. Return to circuit 17.

  The hot water heat exchanger 62 performs heat exchange between the external hot water and the hot water supplied from the use-side heat exchanger 14 of the heat pump 4, thereby further increasing the temperature of the external hot water. In this example, the temperature of the hot water from the outside is increased to a temperature at which the inside of the drying chamber 2 can be 80 ° C. or higher. The warm water from the outside via the warm water heat exchanger 62 is discharged after passing through the warm water jacket 3.

  Here, the three-way valve 41 is controlled by the controller 8 based on the output from the second gas temperature sensor 35 installed in the downstream end portion of the return path from the first heat exchanger 6 toward the drying chamber 2 in the gas circulation path 21. Drive controlled. That is, the controller 8 controls the driving of the blower fan 25 based on the output from the second gas temperature sensor 35, thereby reducing the amount of gas (air volume) passing through the first heat exchanger 6 in the gas circulation path 21. The amount of hot water passing through the first heat exchanger 6 (flow path) in the second liquid circulation path 22 is controlled by adjusting and drivingly controlling the three-way valve 41 based on the output from the second gas temperature sensor 35. adjust. Further, the controller 8 drives and controls the three-way valve 41 to adjust the gas temperature to an appropriate one based on the output from the second gas temperature sensor 35, and uses the first liquid circulation path 17 for hot water. The flow rate of the hot water (fluid) flowing into the heat exchanger 62 is controlled. Thereby, the temperature of the warm water from the outside which flows into the warm water jacket 3 is adjusted.

  Also in this example, the same effect as the sewage sludge drying system 1, 1A can be obtained. In addition, in the sewage treatment plant, a hot water supply system 51 that supplies hot water using digestion gas generated in the digestion process of the sludge 100 in the digestion tank as fuel for combustion equipment such as a boiler is provided together with the sewage sludge drying system 1D. If it is, the hot water supplied from the hot water supply system 51 can be used effectively.

(Other embodiments)
The fluid flowing through the first liquid circulation path 17 may be gas. In other words, the heat pump 4 that uses gas on the use side heat exchanger 14 side can be adopted. In this case, the heat source side heat exchanger 13 can use carbon dioxide as a heat source.

  Further, the drying chamber 2 can be provided with an exhaust mechanism such as an exhaust valve. If the exhaust mechanism is provided, when the saturated water vapor amount of the gas in the drying chamber 2 does not decrease, the gas can be discharged to the outside and the dried gas can be introduced into the drying chamber 2.

  A plurality of sewage sludge drying systems 1 may be provided, and the sludge whose water content has been reduced by the first sewage sludge drying system 1 may be input to the second sewage sludge drying system 1 to further reduce the water content. it can.

1 ・ 1A ・ 1B ・ 1C ・ 1D ・ ・ Sewage sludge drying system 2 ・ ・ Drying room 3 ・ ・ Hot water jacket (temperature bath) 4 ・ ・ Heat pump 5 ・ ・ Condenser 6 ・ ・ First heat exchanger (Heat exchanger), 7 .... second heat exchanger (second heat exchanger), 8 .... controller, 9 .... opening / closing door, 30 .... refrigerant supply path, 61 ... hot water supply path, 62 .. Heat exchanger for hot water, 11 .. First gas temperature sensor, 13 .. Heat source side heat exchanger of heat pump, 14 .. Heat exchanger side of heat pump, 15 .. Heat pump controller, 17. 1 liquid circulation path (first fluid circulation path), 18. first pump, 21 ... gas circulation path, 22 ... second liquid circulation path (second fluid circulation path), 23 ... drainage path, 25 ...・ Blower fan, 27 ・ ・ Second pump, 29 ・ ・ Refrigerant flow passage, 30 ・ ・ Refrigerant supply passage, 31 ・ ・ Third pump , 32 .. Fluid circulation path, 33 .. Fourth pump, 35 .. Second gas temperature sensor, 36 .. Liquid temperature sensor, 41 .. Three-way valve, 45 .. Refrigerant flow path, 51. ..52..Warm water flow passage, 53.54..Temperature tank portion, 61..Hot water supply path, 62..Heat water heat exchanger

Claims (9)

A drying chamber into which sewage sludge is charged;
A temperature vessel for heating the drying chamber;
A heat pump including a heat source side heat exchanger and a use side heat exchanger;
A capacitor,
A heat exchanger,
A first fluid circuit for returning fluid from the use side heat exchanger to the use side heat exchanger via the temperature bath;
A gas circulation path for returning the gas in the drying chamber to the drying chamber via the condenser and the heat exchanger in this order;
A second fluid circuit for returning the fluid from the first fluid circuit to the first fluid circuit via the heat exchanger;
A refrigerant supply path for supplying refrigerant to the capacitor;
A refrigerant heat utilization mechanism for utilizing the heat of the refrigerant heat exchanged with the gas in the capacitor as a heat source of the heat pump,
The condenser condenses the gas by exchanging heat between the gas and the refrigerant to discharge condensed water,
The sewage sludge drying system, wherein the heat exchanger raises the temperature of the gas by heat exchange between the gas and the fluid. In claim 1,
The said 2nd fluid circulation path returns the said fluid of the said temperature tank to the said temperature tank through the said heat exchanger, The sewage sludge drying system characterized by the above-mentioned. In claim 1,
The second fluid circulation path passes the fluid in the forward path of the first fluid circulation path from the use side heat exchanger to the temperature tank through the heat exchanger, and exchanges the use side heat exchange from the temperature tank. A sewage sludge drying system characterized by returning to the return path of the first fluid circulation path toward the container. A drying chamber into which sewage sludge is charged;
A temperature vessel for heating the drying chamber;
A heat pump including a heat source side heat exchanger and a use side heat exchanger;
A capacitor,
A heat exchanger,
A hot water supply path for supplying hot water of a predetermined temperature or higher to the temperature tank;
A hot water heat exchanger installed in the middle of the hot water supply path;
A first fluid circuit that returns fluid from the use side heat exchanger to the use side heat exchanger via the hot water heat exchanger;
A gas circulation path for returning the gas in the drying chamber to the drying chamber via the condenser and the heat exchanger in this order;
A second fluid circuit for returning the fluid from the first fluid circuit to the first fluid circuit via the heat exchanger;
A refrigerant supply path for supplying refrigerant to the capacitor;
A refrigerant heat utilization mechanism for utilizing the heat of the refrigerant heat exchanged with the gas in the capacitor as a heat source of the heat pump,
The condenser condenses the gas by exchanging heat between the gas and the refrigerant to discharge condensed water,
The heat exchanger increases the temperature of the gas by heat exchange between the gas and the fluid,
The sewage sludge drying system characterized in that the warm water heat exchanger increases the temperature of the warm water by heat exchange between the warm water and the fluid. In any one of claims 1 to 4,
The sewage sludge drying system, wherein the refrigerant heat utilization mechanism is a supply path that supplies a refrigerant that has undergone heat exchange with the gas in the condenser to the heat source side heat exchanger. In any one of claims 1 to 4,
The refrigerant heat utilization mechanism includes: a second heat exchanger; and a second refrigerant supply path that supplies the refrigerant that has undergone heat exchange with the gas to the second heat exchanger. A fluid circulation path for circulating a second fluid between the heat source side heat exchanger and the second heat exchanger,
The sewage sludge drying system, wherein the second heat exchanger raises the temperature of the second fluid by heat exchange between the refrigerant and the second fluid. In any one of claims 1 to 6,
The sewage sludge drying system, wherein the fluid is a liquid. In any one of claims 1 to 6,
The sewage sludge drying system, wherein the fluid is steam. In any one of claims 1 to 8,
The sewage sludge drying system, wherein the refrigerant is sewage treated water.

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