JPH0650067B2 - Exhaust heat utilization system - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial Application) The present invention relates to an exhaust heat utilization system, and more particularly to an exhaust heat utilization system adapted to stably supply a heat medium to a turbine.

(Prior Art) Generally, an exhaust heat utilization system includes a heat medium circulation system that circulates a heat medium in each device such as an exhaust heat recovery device, a turbine, a compressor, a regenerator, and a cooler, a generator, and a power converter. , Battery,
It has an electric system including an electric control device, a heater, and the like, and a cooling water system including a cooling water pump, a control valve, and the like.

In this exhaust heat utilization system, especially in the heat medium circulation system, the heat medium is pressurized by the compressor, and this heat medium is supplied to the exhaust heat recovery device via the regenerator. Exhaust heat generated from the heat generator is recovered by the heat medium, and the heated heat medium drives the turbine to rotate. The heat medium that has worked in the turbine is sent again to the cooler via the regenerator, cooled by water or the like in the cooler, and returned to the compressor. A generator is directly connected to the turbine, and when the turbine is rotationally driven by a heat medium, electric power is generated from the generator, and this surplus power is supplied to the grid and the surplus power is supplied to the heat medium circulation system or other power source. , Used as a control power supply.

Furthermore, the cooling water system is used as a cooling source for the heat medium circulating system and the like.

(Problems to be Solved by the Invention) In such an exhaust heat utilization system, since the exhaust heat received by the exhaust heat recovery device uses the exhaust heat of the main equipment, for example, the steam turbine cycle, the exhaust heat is removed by the output of the main equipment. The heat is greatly affected and varied. Therefore, the temperature of the heat medium supplied from the exhaust heat recovery device to the turbine is fluctuated, the turbine is not rotated at a stable speed, and this causes the number of revolutions of the generator to be fluctuated, and constant power cannot be supplied to the system. Problems arise.

Further, the fluctuation of the exhaust heat temperature changes the temperature of the circulating heat medium, and changes the temperature of each device in the heat medium circulation system. Therefore, there is a problem that adjustment of each device of the heat medium circulation system becomes troublesome, and as a result, the rotation of the turbine becomes unstable and the electric power generated from the generator fluctuates.

In order to solve the above-mentioned problems, the present invention detects the pressure, temperature, etc. of the heat medium circulating through each device, and properly controls each device according to the detected values to stably drive the turbine exhaust heat. The purpose is to obtain a usage system.

[Structure of Invention]

(Means for Solving the Problem) The present invention supplies a heat medium pressurized by a compressor to a heat recovery device via a regenerator, and a turbine is heated by the heat medium heated in the heat recovery device. In the exhaust heat utilization system in which the exhaust heat from the turbine is circulated to the compressor through the regenerator and the cooler, the heat medium temperature supplied from the exhaust heat recovery device to the turbine is A first temperature detector for detecting, and a part of the heat medium which is operated by the heat medium temperature detected by the first temperature detector and is supplied to the exhaust heat recovery device, bypasses the exhaust heat recovery device. The exhaust gas heat recovery system further includes a first control valve and a heater operated by a temperature detected by the first temperature detector provided in the exhaust heat recovery device. Turbine? A second temperature detector that detects the temperature of the heat medium exhausted from the turbine, a third temperature detector that detects the heat medium exhausted from the turbine and sent to the cooler via the regenerator, and the compressor A fourth temperature detector that detects the temperature of the heat medium of the regenerator after heat exchange with the heat medium that is supplied to the exhaust heat recovery device from the turbine and is exhausted from the turbine; And a second control valve for operating a part of the heat medium supplied to the regenerator by the controlled heat medium temperature and bypassing the regenerator.

(Operation) In an exhaust heat utilization system in which a heat medium is circulated to the compressor through a compressor, a regenerator, an exhaust heat recovery device, a turbine, a cooler, etc., the heat medium passes through the exhaust heat recovery device. Temperature of the heat medium supplied to the turbine is detected, and a part of the heat medium supplied to the exhaust heat recovery device is bypassed in the exhaust heat recovery device or the heater is operated and supplied to the turbine by the detected temperature. The heating medium temperature is controlled to be heated to a predetermined temperature.

Further, the heat medium supplied from the compressor to the exhaust heat recovery device via the regenerator is exchanged with the heat medium exhausted from the turbine. The inlet temperature and the outlet temperature of each heat medium passing through this regenerator are detected, the heat medium is bypass-controlled in the regenerator by these detected temperatures, and the heat medium temperature supplied from the regenerator to the exhaust heat recovery device is a predetermined temperature. To be controlled.

(Embodiment) An embodiment of the exhaust heat utilization system of the present invention will be described below with reference to the accompanying drawings.

A heat medium circulating system of the exhaust heat utilization system, generally designated by 10, is provided with a compressor 13 for pressurizing a heat medium such as air and gas through a solenoid valve 11 and a regulating valve 12 described later. The heat medium pressurized by the compressor 13 is the control valve 1
4 (hereinafter, referred to as a second regulating valve) and is supplied to a regenerator 15 in which a turbine 16 described later is provided.
Heat exchange with the exhaust heat of. The heat medium that has undergone heat exchange by the regenerator 15 is a control valve 17 (hereinafter referred to as a first regulating valve).
Is supplied to an exhaust heat recovery device 18 via a heat source and heated by exhaust heat from a boiler (not shown) or other heating source, and is supplied to the turbine 16. The turbine 16 is rotationally driven at a predetermined speed.

The second control valve 14 is connected to one end of a bypass conduit 19 that bypasses the regenerator 15, and the other end is connected to the outlet side of the regenerator 15. Further, the first control valve 17 is also connected to one end of a bypass pipe 20 that bypasses the exhaust heat recovery device 18, and the other end is connected to the outlet side of the exhaust heat recovery device 18 for the first control. Valve 17
By adjusting the above, a part of the heat medium bypasses the exhaust heat recovery device 18.

The rotation of the turbine 16 causes the generator 21 connected thereto to rotate. Due to the rotation of the generator 21, electric power is generated from this and the electric power is supplied to a system (not shown). The heat medium that has worked in the turbine 16 is sent to the regenerator 15 and exchanges heat with the heat medium that is supplied from the compressor 13 to the exhaust heat recovery device 18 as described above, and the exhaust heat of the turbine 16 is effective. Used for. This regenerator 15
The heat medium having undergone heat exchange in (1) is sent to the cooler 22 to be cooled and then returned to the inlet side of the regulating valve 12 and is supplied to the compressor 13 again.

By the way, a pressure detector 23 is provided on the discharge side of the compressor 13.
Is provided, the heat medium outflow side of the regenerator 15, the outlet side of the exhaust heat recovery device 18, the exhaust side of the turbine 16, the regenerator 15
On the exhaust gas outflow side and the outlet side of the cooler 22 are provided with temperature detectors 24, 25, 26, 27 and 28, respectively, and a rotation speed detector 29 is provided on the rotating shafts of the turbine 16 and the compressor 13. ing.

Furthermore, a power converter 32 for converting alternating current into direct current is connected to an output terminal of the generator 21 via a circuit breaker 31 controlled by a control device 30 described later, and the output of the power converter 32 is It is sent to the electric storage device 33, and the generator 2
The surplus power of 1 is charged in the battery 33.

A circuit breaker 34, which is controlled by the control device 30 like the circuit breaker 31, is provided between the power converter 32 and the battery 33.
An electric controller 35 such as an SCR is connected to the heater 36 attached to the exhaust heat recovery device 18 by controlling the electric controller 35.

A cooling water pump 38 having a regulating valve 37 is connected to the cooler 22 so that the cooling medium circulated by the cooling water pump 38 cools the heat medium flowing out from the regenerator 15. .

The main part of the control device 30 is as shown in FIG. 2, and includes the pressure detector 23, the temperature detectors 24, 25, and 2.
6, 27 and 28, the detection signal from the rotation speed detector 29 is input, and the adjusting valve 12, the first and second control valves 17, 14 and the adjusting valve 37 are supplied via a converter, a computing unit, an adder / subtractor, etc. A control signal is sent to the heater 36.

That is, the temperature of the heat medium on the outlet side of the exhaust heat recovery device 18 is detected by the temperature detector 25 (hereinafter referred to as the first temperature detector), and this temperature signal is sent to the temperature-current converter 40. Is converted into an electric signal by. This electric signal is sent to the temperature setter 41 for comparison calculation with the set temperature signal, the deviation signal is sent to the PID controller 42, and an output signal based on the deviation is generated. Then, this output signal is applied to the first control valve 17 via the electropneumatic converter 43, the first control valve 17 is controlled according to the deviation signal, and the output side of the exhaust heat recovery device 18 is provided. The temperature of the heat medium is controlled so as to reach a predetermined temperature.

That is, when the temperature of the heat medium on the outlet side of the exhaust heat recovery device 18 becomes equal to or higher than the predetermined temperature, the first control valve 17 is operated and a part of the heat medium flowing into the exhaust heat recovery device 18 is bypassed. The exhaust heat recovery device 18 is bypassed via 20. As a result, the temperature of the heat medium on the outlet side of the exhaust heat recovery device 18 is set to a predetermined temperature.

Further, the electric signal of the temperature-current converter 40 is sent to the limiter 44, and when the electric signal is lower than the limit value defined by the limiter 44, an output signal is generated. This output signal is sent to the temperature setter 45 and is compared with the set temperature signal to generate the deviation signal.
This deviation signal is used as a control signal for the electric controller 35, and is also applied as a control signal to the circuit breakers 31, 34, and the heater 36 is controlled to control the exhaust heat recovery device 18.
Insufficient temperature is replenished.

The temperature detector 24 (hereinafter referred to as the fourth temperature detector) detects the temperature of the heat medium supplied from the regenerator 15 to the exhaust heat recovery device 18, and this temperature signal is sent to the temperature-current converter 46. Is converted into an electric signal by. This electric signal is sent to the temperature setting device 47, is compared with the set temperature signal, and the deviation signal is calculated via the PID controller 48.
Sent to 9.

On the other hand, the temperature detector 26 (hereinafter referred to as the second temperature detector)
Thus, the temperature of the heat medium that has worked in the turbine 16 is detected, and this temperature signal is sent to the temperature-current converter 51 and converted into an electric signal. Further, the temperature detector 27 (hereinafter referred to as the third temperature detector) passes through the regenerator 15 and the cooler 2
The temperature of the heat carrier sent to 2 is detected and this temperature signal is sent to a temperature-current converter 52, where it is converted into an electrical signal. The electric signals of the second temperature detector 26 and the third temperature detector 27 are sent to the addition / subtraction calculator 53 to be subjected to the adjustment calculation, and the addition / subtraction calculation signal is sent to the addition / subtraction calculator 49 via the bias circuit 54.

Therefore, in the addition / subtraction calculator 49, the fourth temperature detector 2 is used.
The signal from No. 4 and the signals from the second temperature detector 26 and the third temperature detector 27 are compared and calculated, and the deviation signal of the electro-pneumatic converter 50 operates similarly to the electro-pneumatic converter 43. The control amount is added to the second control valve 14 via the above, and the supply amount of the heat medium sent to the regenerator 15 is controlled.

That is, the setting signal is supplied via the PID controller 48 so that the temperature of the heat medium supplied from the regenerator 15 to the exhaust heat recovery device 18 reaches the temperature set by the setting device 47.
Send to 9.

On the other hand, when the temperature of the heat medium discharged from the turbine 16 is the second
Of the heat medium sent from the regenerator 15 to the cooler 22 is detected by the third temperature detector 27. The temperature difference between these two heat mediums is sent as an electric signal to the addition / subtraction calculator 53 as an addition / subtraction calculation signal to the addition / subtraction calculator 49 via the bias circuit 54.

The adder / subtractor calculator 49 processes the setting signal and the adder / subtractor calculation signal to calculate an adder / subtractor calculation value such that the temperature of the heat medium supplied from the regenerator 15 to the exhaust heat recovery device 18 becomes appropriate. The second control valve 14 is adjusted and controlled by this operation output signal to adjust the bypass amount of the bypass conduit 19 to control the temperature of the heat medium supplied to the exhaust heat recovery device 18.

The temperature detector 28 detects the temperature of the heat medium discharged from the cooler 22 to the compressor 12. This temperature signal is converted into an electric signal by the temperature-current converter 55 similar to the above. This electric signal is sent to the setting device 56 for setting the temperature required by the cooling machine 22, is compared with the set temperature signal, and the deviation signal is sent to the adjustment calculator 58 via the PID type controller 57. Further, the electric signal sent from the temperature detector 27 via the temperature-current converter 52 and the electric signal sent from the temperature-current converter 55 are added / subtracted by an add / subtract calculator 59, The addition / subtraction signal is given to the bias circuit 60. This bias signal and the PI
The deviation signal from the D-type controller 57 is used as the addition / subtraction calculator 58.
And an addition / subtraction calculation signal is generated. Addition / subtraction calculator 5
The addition / subtraction calculation signal of 8 is sent to the electropneumatic converter 61, and the adjustment valve 3
7 is controlled by an addition / subtraction calculation signal to control the amount of water sent from the cooling water pump 38 to the cooler 22, and the heat medium is
Is controlled so that the temperature is moderate.

The discharge pressure of the heat medium pressurized by the compressor 13 is detected by the pressure detector 23 as an electric signal. This discharge pressure signal is sent to the pressure setting device 62, is compared with the set pressure signal of the compressor 13, and the deviation signal is sent to the high value priority circuit 64 via the PID type controller 63.

The rotation detector 29 detects the number of rotations of the turbine 16 and the compressor 13.

This rotation signal is sent to the frequency converter 65 and converted into an electric signal. This electric signal is sent to the rotation speed setting device 66 and compared with the setting rotation speed of the turbine 16 and the deviation signal thereof is passed through the PID type controller 67 to the high value priority circuit 6
Sent to 4.

In the high value priority circuit 64, the higher one of the discharge pressure signal of the compressor 13 and the rotation speed electric signal of the turbine 16 or the like is applied to the adjusting valve 12 via the electropneumatic converter 68, and the adjusting valve 12 is applied. The opening / closing control of 12 controls the amount of heat medium supplied to the compressor 13.

The exhaust heat utilization system of the present invention detects the temperatures and pressures of the inlet and outlet of the heat medium circulating in the regenerator, the exhaust heat recovery device, the cooler, etc. by the temperature detector, the pressure detector, etc. Since the temperature of the heat medium circulating through the regenerator, the exhaust heat recovery device, the cooler, etc. is controlled from the pressure and the bypass control of the heat medium is performed, the exhaust heat of the exhaust heat recovery device may vary. In this case, the temperature of the heat medium supplied to the turbine can be maintained at a predetermined value. Therefore, stable operation of the turbine can be performed, and good quality electric power can be generated from the generator directly connected to the turbine.

〔The invention's effect〕

As described above, the present invention detects the temperature of the heat medium supplied from the exhaust heat recovery device to the turbine in the exhaust heat utilization system, and controls the heat medium of the exhaust heat recovery device, the bypass control, and the heating temperature control based on the detected temperature. I decided to do it,
The temperature of the heat medium supplied from the exhaust heat recovery device to the turbine can be maintained at a predetermined temperature, and good quality electric power can be generated from the generator directly connected to the turbine.

Further, in the exhaust heat utilization system, the exhaust heat medium of the turbine that exchanges heat with the regenerator, the inlet and outlet temperatures of the heat medium supplied from the regenerator to the exhaust heat recovery device are respectively detected, and the detected temperature of the regenerator is detected. Since the heat medium control and the bypass control are performed, the temperature of the heat medium supplied from the regenerator to the exhaust heat recovery device can be set to a predetermined temperature. as a result,
It is possible to stabilize the temperature of the heat medium supplied to the turbine via the regenerator and the exhaust heat recovery device, and to generate a certain amount of electric power from the generator connected to the turbine.

[Brief description of drawings]

FIG. 1 is a block diagram showing an exhaust heat utilization system of the present invention, and FIG. 2 is a block diagram showing a control circuit in FIG. 10 ... Exhaust heat utilization system, 11 ... Solenoid valve, 12, 3
7 ... Regulator valve, 13 ... Compressor, 14, 17 ... Control valve, 15 ... Regenerator, 16 ... Turbine, 18 ... Exhaust heat recovery device, 21 ... Generator, 20 ... Cooler , 23 ……
Pressure detector, 24, 25, 26, 27 and 28 ... Temperature detector, 29 ... Rotation speed detector, 30 ... Control circuit,
31, 34 ... Circuit breaker, 32 ... Power converter, 33 ...
Battery, 35 ... Electric controller, 36 ... Heater, 40,
46, 51, 52, 55 and 65 ... Temperature-electric converter, 41, 47, 56, 62 and 66 ... Setting device, 4
2, 48, 57, 63 and 67 ... PID controller, 4
9, 53, 58 and 59 ... Addition / subtraction calculator, 43, 5
0, 61 and 68 ... Pneumatic converter, 44 ... Limiter, 54, 60 ... Bias circuit, 64 ... High value priority circuit.

Claims (2)

[Claims] 1. A heat medium pressurized by a compressor is supplied to an exhaust heat recovery device via a regenerator, and a turbine is driven by the heat medium overheated in the exhaust heat recovery device, and from the turbine. Exhaust heat utilization system configured to circulate the exhaust gas of the exhaust gas to the compressor through the regenerator and the cooler, the first temperature detector for detecting the temperature of the heat medium supplied from the exhaust heat recovery device to the turbine. A first control valve that operates by the heat medium temperature detected by the first temperature detector and bypasses a part of the heat medium supplied to the exhaust heat recovery device by the exhaust heat recovery device; An exhaust heat utilization system comprising: a heater that is operated by the temperature detected by the first temperature detector provided in the exhaust heat recovery device. 2. A heat medium pressurized by a compressor is supplied to an exhaust heat recovery device via a regenerator, and a turbine is driven by the heat medium overheated in the exhaust heat recovery device, and from the turbine. An exhaust heat utilization system in which the exhaust gas from the turbine is circulated to the compressor through the regenerator and the cooler, the second detecting the temperature of the heat medium exhausted from the turbine;
Temperature detector, a third temperature detector that detects the temperature of the heat medium that is exhausted from the turbine and sent to the cooler via the regenerator, and the turbine that is supplied from the compressor to the exhaust heat recovery device A fourth temperature detector for detecting the heat medium temperature of the regenerator after heat exchange with the heat medium exhausted from the regenerator, and the regenerator operated by the heat medium temperature detected by each of these temperature detectors. A second control valve for bypassing a part of the heat medium supplied to the regenerator, and the exhaust heat utilization system.