JPH0135267B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a steam turbine plant that improves the efficiency of the steam turbine plant by absorbing the heat of low-temperature water discharged from various plants or factories using an absorption heat pump installed in the boiler water supply system. The present invention relates to a water supply system for a boiler.

Low-temperature water discharged from various plants or factories,
For example, the cooling that cools hot air valves in ironmaking equipment and the drain discharged from factories are low-temperature water of 40° to 50°C (hereinafter referred to as "heat source water"), and the heat of this heat source water remains unchanged until now. Heat was being radiated. In other words, even if we try to absorb the heat of such low-temperature heat source water, there are many cases where there is no heat-accumulating water with a lower temperature level than this, and even if there is, the temperature difference necessary for heat exchange cannot be obtained sufficiently, so This requires a heat exchanger with an enormous heat transfer surface, which necessitates the manufacture of a very large heat exchanger.

Therefore, it is often impossible to collect heat with a normal heat exchanger, and even if it is possible, considering the overall economic efficiency of the production cost of a large heat exchanger and the heat absorption effect from the heat source water, Economic effects could not necessarily be expected. However, even if the temperature is low, if the amount of heat source water is large, the total amount of heat will be enormous.

In view of these circumstances, the inventor of the present application has conducted intensive studies to effectively utilize this enormous amount of waste heat, and as a result, has found that:
The present invention has been developed, and the gist of the present invention is that a deaerator 19 and an absorption heat pump 26 located upstream thereof are installed in a boiler water supply pipe 29 in a steam turbine plant. The heat pump 26 includes an absorber heat exchanger 6 and a condenser heat exchanger 7 connected in series to the boiler water supply pipe 29, a regenerator heat exchanger 8, and The steam branch discharge pipe 30 connected to the steam outlet of the steam turbine 22 has a built-in evaporator heat exchanger 5 connected to the exhaust heat source water supply source, and the steam branch discharge pipe 30 connected to the steam outlet of the steam turbine 22 is connected to the regenerator heat exchanger 8
It is located in the water supply system of the boiler in the steam turbine plant connected to the boiler.

Next, the principle of the absorption heat pump used in the present invention will be explained. The absorption heat pump shown in Fig. 1 is a typical example, and has a built-in evaporator 1, absorber 2, regenerator 3, and condenser 4, each of which has a heat exchanger consisting of a large number of tube groups. The entire structure is completely airtight and kept airtight.

First, in the evaporator 1, which is in a highly vacuum state, the refrigerant sprayed from the refrigerant spraying device 9 onto the tube surface of the heat exchanger 5 evaporates at an evaporation temperature corresponding to the internal pressure, and at that time, heat of vaporization is generated. The refrigerant to be cooled, such as cold water, flowing through the pipes of the heat exchanger 5 is cooled.

In addition, in the absorber 2, the absorption liquid sprayed from the absorption liquid distribution device 10 onto the tube surface of the heat exchanger 6 flows down while being cooled by the cooling water flowing inside the tube, and evaporates in the evaporator 1. Refrigerant vapor is quickly absorbed into the absorber 2. The heat of absorption generated during absorption is taken away by the cooling water passing through the tubes of the heat exchanger 6. The dilute absorption liquid that has absorbed the refrigerant vapor is collected in a reservoir 12 at the lower part of the absorber 2.

The dilute absorption liquid in the reservoir 12 is sent to the heat exchanger 11 through a pipe line by a pump 13, and is heated up.
Furthermore, the refrigerant is introduced into the regenerator 3 and is further heated and heated by the heated refrigerant passing through the pipes of the heat exchanger 8 in the regenerator 3, whereupon the refrigerant is evaporated and separated, and is concentrated to the reservoir 1.
It accumulates to 4. The concentrated absorption liquid in the reservoir 14 passes through the heat exchanger 11 and returns to the absorption liquid distribution device 10 to the absorber 2.
is sprayed onto the tube surface of the heat exchanger 6. In other words, in the heat exchanger 6, the cooling water passing through the pipes takes away the heat of evaporation of the refrigerant and the heat retained in the absorption liquid, and the temperature of the cooling water rises.

The refrigerant vapor evaporated in the regenerator 3 is led to the condenser 4, where the latent heat of the refrigerant vapor is removed by the cooling water flowing through the tubes of the heat exchanger 7 in the condenser 4, and the vapor is condensed and stored. It accumulates to 15. The refrigerant liquid in the reservoir 15 is again sprayed onto the tube surface of the heat exchanger 7 in the evaporator 1 from the refrigerant spraying device 9.

Therefore, the present invention provides an absorption heat pump in the boiler water supply pipe in a steam turbine plant on the upstream side of the deaerator 19, and uses steam from the turbine outlet as a heat source for the regenerator in the absorption heat pump. By passing feed water through the absorber heat exchanger and condenser heat exchanger of the absorption heat pump, and passing exhaust heat source water from outside the steam turbine plant system through the evaporator heat exchanger, the refrigerant vapor that evaporates in the evaporator is The boiler feed water can be preheated by the absorption heat generated when the high-temperature absorption liquid absorbs the water in the absorber, and the heat collected by condensing the refrigerant vapor separated by evaporation from the absorption liquid in the regenerator into refrigerant liquid in the condenser. This is how it was done.

Next, the present invention will be explained in detail with reference to an embodiment shown in FIG.

FIG. 2 is a system diagram showing an example of a steam turbine plant for power generation, and water that has been treated as boiler water through a water purification device passes through a water supply pipe 16 and is stored in a boiler water supply tank 17. This stored boiler water is guided to the deaerator 19 and deaerated by the deaerator feed water pump 18 provided in the boiler feed water pipe 29, and then heated by the high pressure feed water heater 20 to be heated to the boiler. Guided by 21. The steam generated in the boiler 21 is introduced into the generator operation steam turbine (high pressure and low pressure) 22 through the steam pipe, and then cooled in the condenser 23 to become condensed water, which is then returned to the boiler feed water tank 17.
is stored in

In the present invention, in the steam turbine plant as described above, an absorption heat pump 26 is installed in the boiler feed water pipe 29 between the deaerator feed water pump 18 and the boiler feed water tank 17 on the upstream side of the deaerator 19. The absorption heat pump 26 includes an evaporator heat exchanger 5 provided in the evaporator and an absorber heat exchanger 6 provided in the absorber.
and a regenerator heat exchanger 8 provided in the regenerator.
and a condenser heat exchanger 7 provided inside the condenser.

The absorber heat exchanger 6 and the condenser heat exchanger 7 are connected in series to the boiler water supply pipe 29, and the regenerator heat exchanger 8 and the steam outlet of the steam turbine 22 are connected via a steam branch discharge pipe 30. connected,
The evaporator heat exchanger 5 is connected to an exhaust heat source water supply source outside the steam turbine plant system, such as a low temperature water discharge section of various plants or factories. In FIG. 2, reference numeral 25 indicates in-house steam used for heating in the factory and for production in the factory.

Next, the operation of this embodiment will be explained.

First, the boiler water leaving the boiler water supply tank 17 enters the absorber heat exchanger 6 of the absorption heat pump 26 . Here, the heat source water flowing through the evaporator heat exchanger 5 is cooled by the heat of vaporization at the time when the refrigerant sprayed onto the pipe surface from the spraying device evaporates at an evaporation temperature corresponding to the pressure inside the evaporator. Ru. The boiler water is preheated by the absorption heat when the evaporated refrigerant vapor is absorbed by the high-temperature absorption liquid sprayed from the spraying device onto the pipe surface of the absorber heat exchanger 6 in the absorber. This preheated boiler water or boiler water supply tank 17
The boiler water from enters the condenser heat exchanger 7,
The refrigerant vapor evaporated and separated in the regenerator is condensed by the heating medium flowing in the regenerator heat exchanger 8, and is further heated by the heat.

The steam supplied to the regenerator heat exchanger 8 is
It is guided from the outlet side of the steam turbine 22. By doing so, the amount of steam flowing into the condenser 23 is reduced, and the amount of heat released from the condenser 23 to the outside is reduced by that amount, thereby maintaining or improving plant efficiency.

The boiler water heated in this way is guided to the deaerator 19 through the boiler water supply pipe 29 without being cooled down. For example, absorption heat pump 2
If the feed water whose temperature has been raised in step 6 is temporarily stored in a tank, the tank has a large capacity, so the temperature of the feed water, which has been heated up over time, will drop, which is not preferable.

In the deaerator 19, the deaeration temperature of the boiler feed water is uniquely determined by the pressure and temperature of the boiler, and its heat source is branched by a turbine bleed pipe 25, and the pressure is regulated by a pressure regulating valve 28. pipe 2
At 7, it is fed to a deaerator 19. The boiler water degassed by the deaerator 19 is heated by a high-pressure feed water heater 20 and supplied to the boiler 21 . High-temperature, high-pressure steam evaporated in the boiler 21 is guided to a steam turbine 22 to operate it, and then cooled in a condenser 23 and condensed into water, which is stored in a boiler water supply tank 17. The steam turbine 22 also operates a generator.

Next, an example will be explained using a practical numerical example. In the absorption heat pump 26, 250 tons of 55°C wastewater, which is low-temperature wastewater from outside the steam turbine plant system and is normally discarded as factory wastewater, was input to the evaporator heat exchanger 5 as heat source water.
When H is supplied and flows out from the outlet at 42°C, the boiler water temperature at the inlet of the absorber heat exchanger 6 is 30°C.
℃ becomes 75℃ at the outlet of the condenser heat exchanger 7. As a result, the amount of steam supplied to the deaerator 19 was 4.5 tons/
H is saved. Converting this to power generation amount,
It will increase by 943KW/H.

As detailed above, according to the present invention, the absorber heat exchanger 6 and the condenser heat exchanger 7 are connected in series to the boiler water supply pipe 29 in the steam turbine plant, An absorption heat pump 26 incorporating a regenerator heat exchanger 8 and an evaporator heat exchanger 5 connected to an exhaust heat source water supply source outside the steam turbine plant system is provided, and the boiler water is absorbed in the heat pump 26. Since the water is supplied to the deaerator 19 through the mechanical heat exchanger 6 and the condenser heat exchanger 7, low-temperature waste water from outside the steam turbine plant system is used as a heat source water to heat the boiler by the absorption heat pump 26. It is possible to raise the temperature of water and supply the heated boiler water to the deaerator 19 without lowering the temperature.

Further, as a regeneration heat source for the regenerator heat exchanger 8 in the absorption heat pump 26, a part of the steam discharged from the steam turbine is supplied to the regenerator heat exchanger 8 through the steam branch discharge pipe 30. By a simple means, it is possible to reduce the amount of heat dissipated to the outside from the condenser, and therefore, together with the temperature increase of the boiler water, the efficiency of the steam turbine plant can be improved. Since the boiler water is preheated in this way, the waste heat of the low-temperature water that has been left unused can be used extremely effectively, increasing the efficiency of the steam turbine plant, being highly economical, and fully satisfying the technical aspects. It is an industrially significant invention, and its effects are remarkable.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the principle of an absorption heat pump, and FIG. 2 is a system diagram showing an example in which the present invention is implemented in a water supply system for a boiler in a steam turbine plant for power generation. 1...Evaporator, 2...Absorber, 3...Regenerator, 4...Condenser, 5...Evaporator heat exchanger, 6...Absorber heat exchanger, 7...Condenser heat exchanger, 8...Regenerator heat exchanger 17... Boiler feed water tank, 18... Deaerator feed water pump, 19... Deaerator, 22... Steam turbine,
26...Absorption heat pump, 29...Boiler water supply pipe, 30...Steam branch discharge pipe.

Claims (1)

[Claims] 1 A boiler water supply pipe 29 in a steam turbine plant is provided with a deaerator 19 and an absorption heat pump 26 located upstream thereof, and the absorption heat pump 26 is connected in series to the boiler water supply pipe 29. It has a built-in absorber heat exchanger 6, a condenser heat exchanger 7, a regenerator heat exchanger 8, and an evaporator heat exchanger 5 connected to an exhaust heat source water supply source outside the steam turbine plant system. , a water supply system for a boiler in a steam turbine plant, in which a steam branch discharge pipe 30 connected to a steam outlet of a steam turbine 22 is connected to the regenerator heat exchanger 8.