JPH0784852B2 - Cogeneration system - Google Patents

Description

[Detailed Description of the Invention] A Field of Industrial Use Emergency power generator for co-generation and disaster prevention, which generates electricity by a generator driven by a prime mover such as an engine, and collects and uses exhaust heat generated by the prime mover at the same time. The present invention relates to a combined heat and power generation device having an operation as described above, and more particularly to a combined heat and power generation device having a control means for reducing the capacity of a cooler that processes an excess heat amount of the recovered heat storage amount.

B Outline of the Invention The present invention is a co-generation power generator that also operates as an emergency generator for disaster prevention, and allows the hot water circulation system of the exhaust gas heat exchanger to bypass the flow water to the exhaust gas heat exchanger. By providing switching valve means to stop the flow to the exhaust gas heat exchanger and discharge the drain, during normal cogeneration power generation operation, low temperature water is passed through the cooling water heat exchanger and the exhaust gas heat exchanger. The exhaust heat of the engine cooling water and exhaust gas is collected to maximize the heat storage, while the exhaust gas heat exchanger should be bypassed during emergency emergency generator operation and co-generation operation with heat load less than half. Remove the drain and make it empty,
Only the exhaust heat of the engine cooling water is collected in the low-temperature water through the cooling water heat exchanger to store a minimum amount of heat, and in cogeneration operation, the excess heat storage amount is released to the atmosphere by the cooling device and the heat to the heat load is released. In the operation of emergency generators for disaster prevention, the excess heat storage amount was released to the atmosphere by the cooler, and the engine cooling water was controlled within the allowable temperature to balance the heat and reduce the cooler capacity. It is a thing.

C Prior Art A cogeneration system is a power generation system that improves the economical efficiency of the system by utilizing the electric output of the generator driven by the prime mover and the heat output based on the exhaust heat of the prime mover at the same time.

For example, conventionally, the output of a generator driven by an engine is supplied to an electric power load, and at the same time, exhaust heat of engine cooling water is pumped from a low temperature water tank of a system tank having a low temperature water tank and a high temperature water tank through a heat exchanger. Then, the low-temperature water is heated by the exhaust heat of the engine exhaust gas, stored as high-temperature heat storage water in the high-temperature water tank of the system tank, and then supplied to a heat load such as hot water supply. Then, the low temperature water, which has been released by heat due to the heat load and cooled, is sent to the low temperature water tank.

The heat output is generated in proportion to the electric output and is supplied to the heat load.However, when the heat load is light, the heat supply becomes excessive.Therefore, the high temperature water is guided to a cooler such as a cooling tower, and the excess heat amount is supplied. The heat cogeneration system is operated by discharging a quantity of heat corresponding to the above into the atmosphere and sending it to the low temperature water tank to balance the heat.

D Problems to be Solved by the Invention When the cogeneration system as described above is operated as an emergency generator for disaster prevention, since it is an emergency, only the electric output is used and the heat output is not used at all.

For this reason, it is necessary to radiate that heat output in a cooling tower, etc. Therefore, it is necessary for the cooler such as a cooling tower to have a cooling capacity far higher than the cooling capacity required for cogeneration operation. . This cooling capacity requires a cooler capacity that is about twice the amount of heat that can be processed when operating the cogeneration system as an emergency generator for disaster prevention. Even when the heat load is reduced to less than half, there is a problem that a cooler having a large heat capacity is required to handle the excess heat amount.

The present invention has been made in view of the above problems, and by selectively using the exhaust gas heat exchanger, the excess amount of the heat storage amount of the exhaust heat recovered is released to the atmosphere to balance the heat and improve the heat capacity of the cooler. It is an object of the present invention to provide a cogeneration power generation device that can be reduced in capacity.

E Means and Actions for Solving Problems The system tank having the low temperature water tank and the high temperature water tank, the low temperature water in the low temperature water tank is used as the cooling water heat exchanger to recover the exhaust heat of the engine cooling water, and the exhaust gas of the engine is further exhausted. A means for heating this with a gas heat exchanger to conduct water to the high temperature water tank, a means for supplying high temperature water from the high temperature water tank to a heat load to conduct water to the low temperature water tank, a hot water of the high temperature water tank such as a cooling tower Means for cooling through a cooler and conducting water to the low temperature water tank, and switching valve means for bypassing flowing water to the exhaust gas heat exchanger and stopping water supply to the exhaust gas heat exchanger to discharge its drain. The exhaust gas heat exchanger is constituted by a member capable of being heated in an empty state, and the exhaust gas heat exchanger is bypassed by the switching valve means at the time of emergency emergency generator operation for disaster prevention and cogeneration operation with heat load less than half. Only the exhaust heat of the engine cooling water is collected in the hot water that flows through the cooling water heat exchanger to store a minimum amount of heat. The heat quantity is released into the atmosphere by the cooler, and in the operation of the emergency power generator for disaster prevention, the excess heat quantity is exclusively released into the atmosphere by the cooler and the engine cooling water is controlled within the allowable temperature to balance the heat and cool the cooler. The heat capacity will be reduced and the equipment area and cost will be greatly reduced to improve the economical efficiency of the cogeneration power generation equipment.

F Example One example of the present invention will be described below with reference to the drawings.

The figure is a block diagram of a cogeneration system that also has the function of an emergency generator for disaster prevention. 1 is an engine, and a generator 2
To drive. A cooling water heat exchanger 3 recovers heat of the engine cooling water W. Reference numeral 4 denotes an exhaust gas heat exchanger that can be heated empty, and recovers exhaust heat of the exhaust gas G of the engine. V1
1, V12 is a circulation solenoid valve of the exhaust gas heat exchanger 4, V2 is a bypass solenoid valve, V3 and V4 are ventilation solenoid valves and drain-free solenoid valves, respectively, and the circulation solenoid valves V11, V12 and the bypass solenoid valve. , Ventilation solenoid valve, Drain drain solenoid valve V2, V3,
V4 works in reverse by interlocking. 5 is a drain tank. The system tank 6 is composed of a low temperature water tank 61 for storing low temperature water W1 and a high temperature water tank 62 for storing high temperature water W2. 7 is a heat load such as hot water supply, which utilizes the heat of the high temperature water W2 sent from the high temperature water tank. Reference numeral 8 denotes a cooling tower, which releases the excess heat of the high-temperature water W2 to the atmosphere.

P1, P2 and P3 are pumps for pumping low temperature water W1 and high temperature water W2.

Next, the operation of the embodiment will be described.

First, the operation when the device of the present invention is operated as a normal cogeneration system will be described. In this operation, the flow solenoid valves V11 and V12 of the exhaust gas heat exchanger 4 are opened and the bypass solenoid valve V is opened.
2. Close the ventilation solenoid valve V3 and drain drain solenoid valve V4. The circulating engine cooling water W absorbs exhaust heat in the engine 1 and rises in temperature to be sent to the primary side of the cooling water heat exchanger 3 to serve as a heat source. On the other hand, the low temperature water tank 61 of the system tank 6
The low temperature water W1 stored in the pump is pumped by the pump P1 and flows through the secondary side of the cooling water heat exchanger 3.

At this time, the low-temperature water W1 recovers the heat of the engine cooling water W from the primary side of the cooling water heat exchanger 3 and is heated, and then flows into the exhaust gas heat exchanger 4 via the flow solenoid valve V11. To do. The low temperature water W1 collects and heats the exhaust heat of the exhaust gas G of the engine in the exhaust gas heat exchanger 4, and then the flow solenoid valve
It is sent to the high temperature water tank 62 of the system tank 6 via V12 and stored as heat storage high temperature water W2. The high temperature water W2 once stored in the high temperature water tank 62 is pumped by the pump P2 to the heat load 7 for heat utilization. The low-temperature water W1 that has released heat and decreased in temperature is circulated to the low-temperature water tank 61 of the system tank 6 and circulated. When the heat load 7 is lighter than the heat output generated in proportion to the electric output, the cooling tower 8 is operated,
By pumping the high-temperature water W2 in the high-temperature water tank 62 to the cooling tower 8 by the pump P3, and releasing a heat amount equivalent to the excessive supply to the atmosphere, the temperature of the engine cooling water W is controlled within the allowable value to achieve heat balance. Drive. Next, the operation when operating as an emergency generator for disaster prevention in the event of a disaster will be described. In this operation, the exhaust gas heat exchanger 4
The flow solenoid valves V11 and V12 are closed, the bypass solenoid valve V2 is opened to allow the low temperature water W1 to flow to the exhaust gas heat exchanger 4 by bypass, and the ventilation solenoid valve V3 and the drain solenoid valve V4 are opened. The drain of the exhaust gas heat exchanger 4 is discharged to the drain tank 5, and the exhaust gas heat exchanger 4 is not fired.

That is, as in the case of combined heat and power generation operation, the low temperature water W1 stored in the low temperature water tank 61 of the system tank 6 is pumped by the pump P1, and the exhaust heat of the engine cooling water W is recovered in the cooling water heat exchanger 3. Although it is heated and flows, it does not circulate in the exhaust gas heat exchanger 4 because the flow solenoid valves V11 and V12 are closed, and is sent to the high temperature water tank 62 of the system tank 6 via the bypass solenoid valve V2. It is stored and stored as heat storage high temperature water W2. Since this high-temperature water W2 does not collect exhaust heat of exhaust gas, the amount of heat storage decreases compared to the case of combined heat and power generation operation, but in this operation only electric power is supplied and no heat load 7 is supplied at all. It becomes one of the ones where heat is stored. Therefore, in order to prevent the temperature of the engine cooling water W from exceeding the allowable value, the high temperature water W2 is pressure-fed to the cooling tower 8 by the pump P3, and the stored heat is released into the atmosphere to generate the low temperature water W1. It is decided that the water is transferred to the low temperature water tank 61 of the tank 6, and the operation is performed so as to balance the heat.

Moreover, even if the heat load is reduced to less than half in cogeneration power generation operation, the amount of heat storage will be excessively large and the heat dissipation capacity of the cooling tower will need to be large. A solenoid valve is selected in the configuration, the exhaust gas heat exchanger 4 is bypassed to reduce the amount of accumulated heat, and the heat capacity of the cooling tower 8 is reduced.

As a specific numerical example, in the cogeneration system of 400KW diesel generator, diesel engine 400KW output, then the heat exchange amount of the cooling water heat exchanger is 212,000KCal / h, the heat output of the exhaust gas heat exchanger Is 240,000KCal / h, total heat is 1,060,000KCal / h, power output 400KW 32.4%, heat recovery 452,000KCal / h 42.6%, total efficiency 75%. In the conventional emergency generator operation for disaster prevention, 452,000KCal / h is required as a cooler capacity to process the heat recovery amount. However, according to the present invention, the exhaust gas heat recovery amount 240,00
Only heat treatment of 212,000 KCal / h excluding 0 KCal / h will be sufficient.

G Effect of the invention As described above, the present invention is, in a cogeneration system, a hot water circulation system of an exhaust gas heat exchanger, bypassing the exhaust gas heat exchanger and stopping water supply to the heat exchanger. A means for discharging the drain is provided, and in a normal cogeneration power generation operation, the exhaust water of the prime mover is maximally recovered and stored in the hot water flowing through the cooling water heat exchanger and the exhaust gas heat exchanger, On the other hand, when operating an emergency power generator for disaster prevention and co-generation with heat load less than half the heat load, the exhaust gas heat exchanger is bypassed to be empty, and the engine cooling water is used as hot water flowing through the cooling water heat exchanger. Only the exhaust heat of is collected and the minimum heat is stored. In the combined heat and power generation operation, the heat load is supplied and at the same time excess heat is released to the atmosphere by the cooler. Quantity to cooler Since it releases heat into the atmosphere and controls the engine cooling water within the allowable temperature to balance the heat, the heat capacity of the cooler is reduced, the equipment area and cost are greatly reduced, and the cogeneration power generation system is economical. Has an excellent effect that it is further improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a cogeneration system that also operates an emergency generator in case of disaster prevention according to an embodiment of the present invention. 1 is an engine, 2 is a generator, 3 is a cooling water heat exchanger, 4 is an exhaust gas heat exchanger, 5 is a drain tank, 6 is a system tank, 61 is a low temperature water tank, 62 is a high temperature water tank, 7 is a heat load, 8 is a cooling tower, W is engine cooling water, W1 is low temperature water, W2 is high temperature water,
G is exhaust gas, P1 to P3 are pumps, V11 and V12 are flow solenoid valves, V2 is a bypass solenoid valve, V3 is a ventilation solenoid valve, and V4 is a drain solenoid valve.

Claims (1)

[Claims] Claim: What is claimed is: 1. A system tank having a low temperature water tank and a high temperature water tank, low temperature water in the low temperature water tank is used as a cooling water heat exchanger to recover exhaust heat of engine cooling water, and the exhaust gas heat exchanger of the engine is used to recover the exhaust heat. Means for heating and guiding water to the high-temperature water tank, means for supplying high-temperature water from the high-temperature water tank to a heat load to conduct water to the low-temperature water tank, and cooling the hot water in the high-temperature water tank via a cooler to cool the low-temperature water tank. The exhaust gas heat exchanger, and a switching valve means for bypassing the flowing water to the exhaust gas heat exchanger and stopping the flow to the exhaust gas heat exchanger to discharge the drain. A combined heat and power generation device, characterized in that it is constituted by a member that can be heated.