JP6447769B2 - Operation method of heat pump steam generator and heat pump steam generator - Google Patents

Description

  The present invention relates to a heat pump type steam generator that recovers exhaust heat from factory wastewater and generates steam.

As one of the steam generators, there is a heat pump steam generator using a heat pump. A heat pump steam generator is a combustion system steam generator that generates steam by recovering waste heat from waste water such as factory effluent and used cooling water, and generates steam using boiler equipment, etc. Compared to the above, there are advantages such as low running cost and reduced CO ₂ emission.

  In a heat pump device, a compressed high-temperature refrigerant is used as a heat medium. Usually, the temperature and pressure of the refrigerant are measured, and the degree of superheat calculated from the refrigerant is controlled so as to always maintain a certain value or more.

  However, when starting the heat pump type steam generator after it has been stopped for a long time, the temperature of each part of the device is in a state close to room temperature, so the gas that has recovered the exhaust heat and evaporated is cooled and condensed in the compressor, Causes equipment damage due to compression.

  In order to solve such a problem, in Patent Document 1, when the heat pump type steam generator is started after being stopped for a long time, the amount of heat transferred from the exhaust water to the refrigerant is controlled by the exhaust heat recovery device. Preheating operation is performed at a low gas refrigerant temperature, and liquid compression due to condensation of the gas refrigerant in the compressor is prevented.

JP 2008-8595 A

  However, the apparatus according to Patent Document 1 has a disadvantage that since the specific heat of water that is water to be heated of the steam generation apparatus is large, the temperature rise of the apparatus is hindered and the startup time is long until steady operation is possible. .

  Accordingly, an object of the present invention is to provide a heat pump type steam generator capable of shortening the start-up time until steady operation is possible.

In order to achieve the above object, in the operation method of the heat pump steam generator according to the present invention, when the heated water discharge condition is satisfied, the heated water is discharged from the heat pump steam generator ,
After completing the discharge of the heated water, the path for discharging the heated water is closed, the heat pump cycle is operated, and the heated water supply condition to the heated pump steam generator is established from the time when the heated water supply condition is satisfied. Is started .

Moreover, the heat pump steam generator according to the present invention is provided with an exhaust heat recovery device, a compressor, a condenser, and a throttle expander, and in that order, a heat pump portion in which a refrigerant circulates and the hot water into the exhaust heat recovery device A hot water supply unit that supplies water to the condenser, a steam generation unit that generates steam based on the heated water output from the condenser, and at least the target water in the condenser A discharge unit that discharges heated water ; an on- off valve that is provided in the discharge unit and opens when the heated water is discharged; and closes after the discharge is completed; and when the heated water discharge condition is satisfied, the condenser is heated And a controller for starting the supply of water .

  ADVANTAGE OF THE INVENTION According to this invention, the starting time of a heat pump type steam generator can be shortened, and also the amount of waste heat water supplied to a waste heat recovery device required for temperature rising can be minimized.

It is a schematic block diagram of the heat pump type steam generator which is an embodiment of the present invention. It is a flowchart of the water supply control at the time of starting in embodiment of this invention. It is a flowchart of the water supply control at the time of starting in the modification of this invention.

  First, a first embodiment of a heat pump steam generator according to the present invention will be described. FIG. 1 is a schematic configuration diagram of a heat pump type steam generator in the first embodiment. The heat pump apparatus 1 is roughly divided into a heat pump unit 100, a hot water supply unit 200, a steam generation unit 300, a discharge unit 400, and a control unit 500.

  The heat pump unit 100 is configured to collect heat from the hot water flowing through the hot water supply unit 200 and transfer the heat of the refrigerant to the heated water flowing through the steam generation unit 300 via the circulating refrigerant. ing.

  The heat pump unit 100 is provided with an exhaust heat recovery device 110, a compressor 120, a condenser 130, and a throttle expander 140, which are connected by a refrigerant flow path L10 so that the refrigerant circulates and flows in that order. Further, a thermometer 150 and a pressure gauge 160 for measuring the refrigerant state are provided between the condenser 130 and the throttle expander 140, and a thermometer 170 is provided between the compressor 120 and the condenser 130, respectively. Yes.

  The hot water supply unit 200 introduces hot water such as factory wastewater from outside the system into the exhaust heat recovery device 110 via the hot water supply flow path L20a, and transfers heat to the refrigerant. The warm water used for heat exchange is discharged out of the system via the warm water discharge channel L20b.

  The steam generation unit 300 is provided with a feed water pump P31, a condenser 130, and a gas-liquid separator 310. Supply water as heated water is supplied from an external water supply source to the condenser 130 through a supply water flow path L30.

  The gas-liquid two-phase flow of hot water and steam generated from the supply water in the condenser 130 is supplied to the gas-liquid separator 310 through the separated fluid flow path L40.

  A steam flow path L50 is connected to the upper part of the gas-liquid separator 310 to supply steam to the steam utilization facility 610. In addition, a circulating hot water flow path L70 is connected to the lower part of the gas-liquid separator 310, and hot water is returned to the supply water flow path L30 before the condenser 130.

  In the drainage section 400, the drainage flow path L60 is branched from the separated fluid flow path L40, and the heated water is discharged from the condenser 130. A solenoid valve 410 is provided in the drainage channel L60.

  The control unit 500 includes a microcomputer (not shown) including, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Randam Access Memory), and the like. The microcomputer reads and executes a program stored in the ROM, and inputs measurement values detected by detection units such as a thermometer 150, a thermometer 170, and a pressure gauge 160 provided in the heat pump unit 100, or Based on a timer provided therein, the rotational speed of the feed water pump P31, the opening degree of the electromagnetic valve 410, the throttle expander 140, and the rotational speed of the compressor 120 are controlled.

  Next, operation | movement of the heat pump type steam generation apparatus of this invention is demonstrated along the flow of heat.

(About refrigerant)
The refrigerant is heated by heat exchange with the hot water supplied from the hot water supply flow path L <b> 20 a in the exhaust heat recovery device 110, becomes a gas, and is sent to the compressor 120. The refrigerant in a gaseous state is compressed as a gas by the compressor 120, becomes a high temperature and a high pressure, and is sent to the condenser 130.

  The high-temperature and high-pressure refrigerant is condensed by heat exchange with the supply water supplied from the supply water flow path L30 in the condenser 130 to become a liquid. The refrigerant that has become liquid is decompressed in the expansion expander 140 and then introduced again into the exhaust heat recovery unit 110.

  An electronic expansion valve is most suitable as the throttle expander 140 listed here, but a manual expansion valve, a constant pressure expansion valve, a temperature expansion valve, an orifice, a capillary, etc. may be appropriately selected according to the application and configuration. good.

(About supply water)
Supply water is supplied from a water supply source by a supply water pump P31, and merged with hot water (circulated hot water) sent from the gas-liquid separator 310 via a circulating hot water flow path L70 to become mixed hot water, which is condensed. Introduced into the vessel 130. The mixed hot water introduced into the condenser 130 is heated by heat exchange with the refrigerant in a high-temperature and high-pressure state, becomes a gas-liquid two-phase flow of hot water and steam, and passes through the separated fluid flow path L40. Introduced into the separator 310.

  The gas-liquid two-phase flow of hot water and steam introduced into the gas-liquid separator 310 is separated into steam and hot water. The steam stored in the gas phase portion of the gas-liquid separator 310 is supplied to the steam utilization facility 610 via the steam flow path L50. Moreover, the hot water stored in the liquid phase part of the gas-liquid separator 310 is merged into the supply water flow path L30 via the circulating hot water flow path L70.

  Here, the gas-liquid two-phase flow may be transferred in a state of applying high pressure and high-pressure hot water. In this case, a flash tank may be provided as a gas-liquid separator instead of the gas-liquid separator, and the gas-liquid separation may be performed after vaporizing high-pressure hot water by decompression.

A drainage channel L60 is branched from the separated fluid channel L40, and the heated water is discharged to the outside.
It is desirable that the drainage flow path L60 be arranged so that the water to be heated in the condenser 130 can be discharged naturally by opening the atmospheric pressure. By branching from the lowest position of the condenser 130, the drainage from the condenser can be reliably performed by the natural drainage by the open air.
If it drains from the inside of the condenser 130, a branch position is not limited to this. Further, a water drain pump may be provided to discharge water actively. In this case, the water in the condenser 130 can be quickly drained regardless of the branch position of the drainage flow path L60.
This drainage flow path L60 is branched from any one of the supply water flow path L30, the gas-liquid separator 310, and the circulating hot water flow path L70 as shown by the broken line in FIG. Good. Moreover, the drainage flow path L60 may be branched from two or more of these, and in that case, it may be merged in the middle.
Further, a valve may be provided before and after the condenser 130 to isolate the inside of the condenser 130 and then discharge the non-heated water in the condenser 130. In this case, since the site | part used as drainage becomes only in the condenser 130, the time concerning drainage can be shortened.

  Next, the water supply control flow at the time of starting in 1st embodiment of this apparatus is demonstrated using the flowchart of FIG.

First, it is determined whether the heated water drainage condition is satisfied when the apparatus is activated (S1). This determination is based on one of the indicated values of the thermometer 150, the thermometer 170, and the pressure gauge 160, or the value of the degree of supercooling obtained by combining temperature and pressure. When temperature or pressure is used as a reference, high temperature start is selected if the measured value is equal to or greater than a predetermined value, and low temperature start is selected if the measured value is less than the predetermined value. When the degree of supercooling is used as a reference, low temperature activation is selected if the degree of supercooling is equal to or higher than a predetermined value, and high temperature activation is selected if it is less than the predetermined value. The degree of supercooling is the temperature difference between the liquid saturation temperature at a certain pressure and the measured refrigerant temperature. The saturation temperature of the liquid at a certain pressure can be obtained from a pressure temperature table or the like. By controlling the degree of supercooling of the refrigerant at the outlet of the condenser 130 to be less than a certain level, the refrigerant can be reliably vaporized in the throttle expander 140.
The reference value is set as appropriate from the design value or from the operation and configuration of the apparatus.

  If it is determined that the start is high temperature, the system immediately shifts to normal operation. Moreover, when it determines with low temperature starting, a waste_water | drain process is started.

  In the cold start, first, the electromagnetic valve 410 is opened to perform drainage treatment (S2). A manual valve, a three-way valve, or the like may be appropriately employed instead of the electromagnetic valve 410 depending on the application or installation location.

  When the waste water treatment is completed (S3), the electromagnetic valve 410 is closed (S4). If the drainage completion condition is not satisfied, the process waits at this step until the condition is satisfied. As a condition for completing this wastewater treatment, when a preset time has elapsed after the start of drainage, or when the water level of the condenser 130 and the gas-liquid separator 310 is interlocked, the water level of the gas-liquid separator 310 is This is the case when the level is less than a preset value. When employing the latter, it is desirable to provide a differential pressure type level meter in the gas-liquid separator.

After the drainage is completed, the compressor 120 is started (S5). When the compressor 120 is activated, the heat pump unit 100 starts the circulation of the refrigerant. However, since the water to be heated is drained here, the heat of the refrigerant is used to preheat each part of the heat pump unit 100. When the heat pump unit 100 is sufficiently preheated and the heated water supply condition is satisfied (S6), the supply water pump P31 is activated (S7). If the heated water supply condition is not satisfied, the process waits at this step until the condition is satisfied.
As this heating water supply condition, the case where the temperature of the refrigerant | coolant measured with the thermometer 150 becomes more than the preset temperature is mentioned. The position of the thermometer 150 can be appropriately selected from between the compressor 120 and the throttle expander 140.
Further, the temperature of the refrigerant may be measured at two places, the inlet and the outlet of the condenser 130, and the temperature difference may be used as a criterion for determining the heated water supply condition. In this case, when the temperature difference between the two thermometers is less than a certain level, it is determined that the condenser has been sufficiently preheated, and the feed water pump P31 is activated.
Alternatively, the degree of supercooling of the refrigerant at the outlet of the condenser 130 may be obtained from the values of the thermometer 150 and the pressure gauge 160, and used as a criterion for determining the heated water supply condition. In this case, when the degree of supercooling becomes less than a certain level, the supply water pump P31 is activated. The position of the thermometer 150 is appropriately selected from between the compressor 120 and the throttle expander 140, and the position of the pressure gauge 160 is appropriately selected from between the condenser 130 and the throttle expander 140.

Moreover, it is good also as a judgment criterion of to-be-heated water supply conditions by the timer setting after drainage completion. In this case, when the timer has elapsed after completion of drainage, it is determined that the condenser has been sufficiently preheated, and the feed water pump P31 is activated.
The heated water discharge condition and heated water supply condition may refer to the same value of the detection unit, or different detection units may be used. Moreover, the combination is also free and can be selected as appropriate according to the design and operating conditions.

  The amount of water supplied to the condenser 130 is continuously adjusted by making the rotation speed of the supply water pump P31 variable by an inverter and performing control based on a signal from the control unit 500. Alternatively, an electromagnetic valve (not shown) may be provided in the supply water flow path L30, and the flow rate may be adjusted by controlling the opening degree of the electromagnetic valve.

  As specific control, for example, the degree of supercooling of the refrigerant is obtained from the measured values of the thermometer 150 and the pressure gauge 160, and the rotation speed of the supply water pump P31 or the solenoid valve is adjusted so that the degree of supercooling of the refrigerant becomes constant. By controlling the opening degree by PID, the refrigerant discharged from the condenser 130 is maintained in a liquid state (S8).

When the normal operation start condition is satisfied (S9), the operation shifts to the normal operation. If the normal operation start condition is not satisfied, the process waits at this step until the condition is satisfied. The normal operation start condition is the condensation obtained from the values of the thermometer 150 and the pressure gauge 160 when the temperature of the refrigerant measured by the thermometer 150 or the thermometer 170 is equal to or higher than a preset temperature. For example, when the degree of supercooling of the refrigerant at the outlet of the vessel 130 becomes less than a certain level.
During normal operation, the mass Q1 of the supplied water is often controlled to be the total amount of the mass Q2 of the steam taken out from the steam channel L50 and the mass Q3 drained from the drain channel L60.

  Next, a modified example of the water supply control flow at the time of starting the apparatus will be described with reference to the flowchart of FIG. Since the device configuration is the same as that of the first embodiment, the description thereof is omitted.

In a modified example, the waste water treatment is performed when the operation is stopped, not when the apparatus is activated.
When the heated water discharge condition is satisfied during the operation stop (S1), the waste water treatment is started (S2). If there is a start command before the heated water discharge condition is satisfied (S11), the operation shifts to normal operation immediately after the start. If neither condition is satisfied, the process waits at this step until either condition is satisfied.
As this heated water discharge condition, when a preset time has elapsed after the operation stop, when any of the values measured by the thermometer 150 and the pressure gauge 160 during the operation stop falls below a preset value, Or it is the case where the degree of supercooling of the refrigerant obtained from the temperature measured by the thermometer 150 and the pressure measured by the pressure gauge 160 becomes a certain value or more. When this condition is satisfied, the waste water treatment is started.

  If there is no start command (S12) at the stage where drainage is completed, the apparatus stops after the drainage is completed, and the next start is started from the stage (S5) where the compressor 120 is started. When the apparatus is activated during the wastewater treatment, the compressor 120 is activated after completion of the wastewater treatment. Subsequent operations are the same as those in the first embodiment.

  In this modified example, it is not necessary to wait for the completion of the waste water treatment when the apparatus is activated, so that the activation time can be further shortened.

  As described above, the heat pump device according to the present invention controls the heat pump cycle to operate normally while minimizing the amount of heat absorbed by the water to be heated. It is possible to provide a heat pump type steam generator that can be increased and can be started in a short time.

1: Heat pump device 100: Heat pump unit 110: Waste heat recovery device 120: Compressor 130: Condenser 140: Throttle expander 150: Thermometer (between condenser and throttle expander)
160: Pressure gauge 170: Thermometer (between compressor and condenser)
200: Hot water supply unit 300: Steam generation unit 310: Gas-liquid separator 400: Discharge unit 410: Solenoid valve 500: Control unit 610: Steam use facility L10: Refrigerant flow path L20a: Hot water supply flow path L20b: Hot water discharge flow path L30: Supply water flow path L40: Separation fluid flow path L50: Steam flow path L60: Drainage flow path L70: Circulating hot water flow path P31: Supply water pump

Claims (12)

Heat is recovered from the hot water to the refrigerant using a heat pump cycle, and the recovered heat is transferred from the refrigerant to the heated water.
In the operation method of the heat pump type steam generator for generating steam,
When the heated water discharge condition is satisfied, the heated water is discharged from the heat pump steam generator ,
After the discharge condition of the heated water is satisfied, the path for discharging the heated water is closed,
The supply of the heated water to the heat pump type steam generating device is started from the time when the heat pump cycle is operated and the heated water supply condition is satisfied . how to drive.   When the heat pump cycle is stopped or started, the state of the heat pump steam generator is determined based on the heated water discharge condition, and the heated water is discharged based on the determination result. The operation method of the heat pump type | formula steam generator of Claim 1. In a heat pump type steam generator that recovers heat from hot water to a refrigerant and generates the steam by transferring the recovered heat from the refrigerant to heated water.
A heat pump unit provided with an exhaust heat recovery unit, a compressor, a condenser, and a throttle expander, in which refrigerant flows and circulates in that order;
A hot water supply unit for supplying the hot water to the exhaust heat recovery unit;
A steam generator for supplying heated water to the condenser and generating steam based on the heated water output from the condenser;
A discharge unit that discharges at least the heated water in the condenser when the heated water discharge condition is satisfied,
An on-off valve that is provided in the discharge unit, opens when the heated water is discharged, and closes after a discharge condition is satisfied;
A controller that operates the heat pump cycle and starts supplying the heated water to the condenser from the time when the heated water supply condition is established;
A heat pump steam generator characterized by comprising: When the heat pump cycle is stopped or started, the state of the heat pump steam generator is determined, and when the heated water discharge condition is satisfied, the heated water is discharged from the condenser. The heat pump type steam generator according to claim 3.   The discharge of the heated water is performed when the first refrigerant temperature in either the compressor outlet or the throttle expander inlet in the heat pump cycle becomes less than a first determination value. Item 5. The heat pump steam generator according to Item 3 or 4.   The discharge of the heated water is performed when the first refrigerant pressure in any of the compressor outlet and the throttle expander inlet in the heat pump cycle becomes less than a second determination value. Item 5. The heat pump steam generator according to Item 3 or 4.   When the degree of supercooling obtained from the second refrigerant temperature and the second refrigerant pressure at the condenser outlet at either the compressor outlet or the throttle expander inlet in the heat pump cycle is equal to or higher than the third determination value. The heat pump steam generator according to claim 3 or 4, wherein the heated water is discharged.   The heat pump steam generator according to claim 3 or 4, wherein when the elapsed time after the heat pump cycle is stopped is equal to or greater than a fourth determination value, the water to be heated is discharged.   The heat pump type steam generator according to claim 8, further comprising a timer for measuring the elapsed time.   The heat pump system according to any one of claims 3 to 9, wherein the pipe of the discharge unit is branched from a position where the water to be heated in the condenser is naturally discharged by opening the atmospheric pressure. Steam generator.   The heat pump steam according to any one of claims 3 to 9, wherein the pipe of the discharge unit is branched from a position where the heated water in the condenser can be actively discharged by a pump. Generator.   12. The throttle expansion device according to claim 3, wherein the expansion device is one of an electronic expansion valve, a manual expansion valve, a constant pressure expansion valve, a temperature expansion valve, an orifice, and a capillary. Heat pump steam generator.