JPH05296009A - Exhaust heat recovery system for steam turbine equipment - Google Patents

Abstract

PURPOSE:To provide an exhaust heat recovery system which utilizes exhaust heat of a steam turbine condenser to obtain hot water for heating and which is able to cope with variation of a heating load. CONSTITUTION:Cooling water drainage from a condenser 4 of a steam turbine 2 is utilized as heat source water, which is fed to an evaporator 5c through a heat source water circulation line 8 arranged between the condenser 4 and the evaporator 5c of a refrigerator 5, and the refrigerator 5 is operated as a heat pump so as to obtain hot water for heating from a condenser 5b. In relation to the heat source water circulation line 8, a bypass line 10 is provided for returning a part of the heat source water from midway of the circulation line 8 via a cooling tower 9 to the condenser 4, and a ratio of feeding quantity of the heat source water to the evaporator 5c to a feeding quantity thereof separated to the bypass line 10 is adjusted in compliance with variation of a heating load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat recovery system for steam turbine equipment applied as a cogeneration system for steam power generation.

[0002]

2. Description of the Related Art Recently, as an effective utilization method of thermal energy for a refuse incinerator in a city, steam is generated in a boiler attached to a refuse incinerator, and steam is used for steam power generation and local use. A cogeneration system for cooling and heating is becoming widespread, and one example is a cogeneration system that obtains cold water for cooling by operating an absorption refrigerator using steam extracted from a steam turbine that drives a generator as a heat source. It has been known.

On the other hand, in addition to the refrigerating operation, the refrigerator can be operated by a heat pump in which heat is taken in from the evaporator and hot water for heating is obtained from the condenser side. In addition, hot cooling wastewater from the steam turbine condenser is used as heat source water to pass through to the evaporator of the refrigerator to obtain hot water for heating from the condenser side, and at the same time, to pass through the evaporator to lower the temperature. An exhaust heat recovery system using a heat pump that returns the generated water as cooling water to the condenser again has been proposed and its development is in progress.

[0004]

By the way, as described above, in the exhaust heat recovery system which utilizes the exhaust heat of the steam turbine condenser to operate the refrigerator by the heat pump to obtain the hot water for heating, The amount of heat taken from the condenser by the evaporator of the refrigerator is determined by the load of the condenser, that is, the operating conditions of the steam turbine. For this reason, if the entire amount of the cooling waste water discharged from the condenser is directly passed to the evaporator of the refrigerator, it is not possible to cope with the case where the heating load fluctuates greatly like district heating.

The present invention has been made in view of the above points, and by improving the exhaust heat recovery system of the steam turbine equipment described above, it is possible to sufficiently cope with fluctuations in the load of the condenser and the heating load. It is an object of the present invention to provide an exhaust heat recovery system as described above.

[0006]

In order to solve the above problems, in the exhaust heat recovery system of the present invention, the heat source water circulation line connected between the condenser and the evaporator of the refrigerator is used. A bypass line that returns a part of the heat source water to the condenser from the middle of the circulation line to the condenser via the cooling tower is provided, and the heat source water flow to the evaporator and the bypass line in response to the fluctuation of the heating load. The operation shall be performed by adjusting the ratio with the flow rate of the divided water flow.

Here, as the refrigerator in the above-mentioned structure, an absorption refrigerator that operates by supplying steam extracted from a steam turbine to a regenerator can be adopted. In addition, in order to obtain cold water for cooling from the refrigerator in the summer using the exhaust heat recovery system, in addition to the heat source water circulation line connected between the evaporator of the refrigerator and the condenser, the cold water supply line It is also possible to obtain cold water for cooling from the evaporator through a cold water supply line after connecting the heat source water circulation line to the heat source water circulation line from the evaporator.

[0008]

In the above construction, the cooling tower works to cool the cooling waste water of the condenser diverting from the middle of the heat source water circulation line to the bypass line to lower the temperature, and to return it to the condenser again via the circulation pump. When the heating load fluctuates during the heat pump operation, the ratio between the amount of cooling waste water supplied from the condenser to the evaporator of the refrigerator as heat source water and the amount of water flow divided into the bypass line is adjusted. As a result, the amount of heat taken into the evaporator of the refrigerator can be appropriately adjusted according to the fluctuation of the heating load.

Further, by adopting the absorption type refrigerator as the refrigerator, the refrigerator can be operated by using the steam extracted from the steam turbine without using the compressor. Further, if the refrigerator is operated in a freezing state with the heat source water circulation line separated from the evaporator, cold water for cooling can be obtained through the cold water supply line connected to the evaporator.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system diagram of an embodiment of the present invention. In the figure, 1 is a boiler installed in an incinerator of a refuse incinerator, 2 is a steam turbine operated by the steam generated by the boiler 1, 3 is a generator connected to the steam turbine 2, and 4 is steam having a cooling coil 4a built therein. Turbine 2 surface condenser,
Reference numeral 5 is an absorption refrigerator. Here, the absorption refrigerator 5 is
The regenerator 5a, the condenser 5b, the evaporator 5c, and the absorber 5d are provided, and the steam extracted from the steam turbine 2 is supplied to the regenerator 5a as a heat source for operation. The refrigeration cycle of such an absorption chiller is well known, and the description thereof is omitted here.

On the other hand, between the cooling coil 4a of the condenser 4 and the evaporator 5c of the refrigerator, the cooling coil 4a again passes through the evaporator 5c, the cooling tower 6 and the circulation pump 7 and is again cooled. The heat source water circulation line 8 returning to
When the refrigerator 5 is operated as a heat pump, the high-temperature cooling drainage discharged from the cooling coil 4a of the condenser 4 is passed as the heat source water to the evaporator 5c of the refrigerator 5, and is passed through the absorber 5d and the condenser 5b. I try to get hot water for heating. Further, with respect to the heat source water circulation line 8, the bypass line 10 is branched from the middle of the line and passes through the cooling tower 9.
In addition to the heat source water circulation line 8 described above, the evaporator 5c further includes a cold water supply line 1 for obtaining cold water for cooling.
1 is connected and piped. In addition, 12 to 16 are open / close valves connected to various parts of the line.

In order to obtain hot water for heating in the winter with such a configuration, basically the valves 12 and 14 are opened and the valves 13 and 14 are opened.
Cooling coil 4 of condenser 4 with 15 and 16 closed
The high-temperature cooling waste water discharged from a is passed as the heat source water to the evaporator 5c of the refrigerator 5, and the waste heat recovered by the condenser 4 is transferred to the evaporator 5
give to c. Thereby, the refrigerator 5 operates as a heat pump, and hot water for heating is obtained through the condenser 5b and the absorber 5d. Although the cooling wastewater loses heat in the process of flowing through the evaporator 5c, the water temperature drops, but since it is slightly higher than the cooling water temperature required for the condenser, it is cooled by passing through the cooling tower 6 and then again. Cooling coil 4 of condenser 4 via circulation pump 7
reflux to a.

Here, when the heating load is small, the valve 13 connected to the bypass line 10 is opened, and the opening degree of the valve 13 is adjusted to divert a part of the cooling drainage from the middle of the circulation line 8 to the bypass line 10. .. As a result, the amount of heat source water flowing through the evaporator 5c of the refrigerator 5, and thus the amount of heat taken in by the evaporator 5c, corresponds to the heating load at that time. The cooling wastewater that has been split into the bypass line 10 is cooled by the cooling tower 9, and then merges with the water that has passed through the evaporator 5c and the cooling tower 6 and returns to the condenser side again. By adjusting the ratio of the flow rate of the heat source water flowing to the evaporator 5c and the flow rate of the water split to the bypass line 10 in this manner, the heat of the heat pump can be adjusted in response to the fluctuation of the heating load or the fluctuation of the load of the condenser. The output can be adjusted.

On the other hand, when obtaining cold water for cooling in the summer,
The valves 12 and 14 are closed to disconnect the heat source water circulation line 8 from the evaporator 5c, and the valves 15 and 16 are opened to flow cooling water to the cold water supply line 11 connected to the evaporator 5c, and the refrigerator 5 is operated in this state. To do. As a result, the water flowing in the cold water supply line 11 is cooled by the evaporator 5c, and cold water for cooling is obtained.

In the illustrated embodiment, an absorption type refrigerator is used as the refrigerator, but a compression type refrigerator may be used instead of the absorption type refrigerator.

[0016]

As described above, according to the exhaust heat recovery system of the steam turbine facility according to the present invention, the heat source water circulation line connected between the condenser and the evaporator of the refrigerator is
By installing a bypass line that returns part of the heat source water from the middle of the circulation line to the condenser via the cooling tower, the exhaust heat recovered from the condenser can be used by operating the refrigerator as a heat pump. Then, the hot water for heating required for district heating is obtained. Moreover, in this case, by adjusting the ratio between the amount of heat source water flowing to the evaporator of the refrigerator and the amount of water flowing to the bypass line, it is possible to easily cope with fluctuations in heating load and fluctuations in condenser. Can be made

Further, by adopting an absorption type refrigerating machine as the refrigerating machine, the refrigerating machine can be operated by using the extracted steam of the steam turbine as a heat source. Further, when cooling is required in the summer, the heat source water circulation line is used. The cooling water is obtained through the cold water supply line connected to the evaporator by disconnecting from the evaporator and operating the refrigerator.

[Brief description of drawings]

FIG. 1 is a system diagram of an exhaust heat recovery system for steam turbine equipment according to an embodiment of the present invention.

[Explanation of symbols]

 2 Steam turbine 4 Condenser 5 Absorption refrigerator 5a Regenerator 5b Condenser 5c Evaporator 5d Absorber 8 Heat source water circulation line 9 Cooling tower 10 Bypass line 11 Cold water supply line

Claims (3)

[Claims] 1. An exhaust heat recovery system for steam turbine equipment, which obtains hot water for heating by utilizing exhaust heat of a steam turbine condenser, wherein the cooling waste water discharged from the surface condenser is used as heat source water to evaporate a refrigerator. In the one in which water is passed through the condenser and the refrigerator is operated as a heat pump to obtain hot water for heating from the condenser, the heat source water circulation line piped between the condenser and the evaporator of the refrigerator is used for the heat source water. A bypass line that returns a part of the circulation line to the condenser via the cooling tower is provided, and the amount of heat source water that flows to the evaporator and the amount of water that splits to the bypass line in response to changes in heating load. The exhaust heat recovery system for steam turbine equipment, which is operated by adjusting the ratio of 2. The exhaust heat recovery system according to claim 1, wherein the refrigerator is an absorption refrigerator that operates by supplying steam extracted from a steam turbine to a regenerator. Exhaust heat recovery system. 3. The exhaust heat recovery system according to claim 1, wherein a cooling water supply line is connected to the evaporator of the refrigerator in addition to the heat source water circulation line connected between the evaporator and the condenser, and during cooling operation. An exhaust heat recovery system for steam turbine equipment, characterized in that the heat source water circulation line is separated from the evaporator, and then cold water for cooling is obtained from the evaporator through a cold water supply line.