JPS5912843B2 - Heat recovery equipment in power generation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an energy recovery system that recovers and utilizes waste heat from power generation equipment.

In this specification, "cooling load" includes not only cooling load but also loads that require cooling heat such as refrigeration load, and "heating load"
In addition to heating loads, this includes loads that require heat, such as hot water supply loads.

Conventionally, the purpose of power generation equipment was simply to obtain the necessary electric power, and the waste heat emitted from the generator or prime mover was wasted into the atmosphere or cooling water.

In order to prevent this, a waste heat recovery system as shown in FIG. 1 has been conventionally considered.

That is, the waste heat generated from the power generation equipment 1, which is composed of a generator 3 and a prime mover 4 and which bears the electric power of the electric power load 10 and the electric motor of the compression refrigerator 6, is recovered by the heat recovery device 2, and the generated heat medium vapor is recovered. through a pipe 11 to an absorption refrigerator 50 and a generator 12
The absorption chiller 5 is operated to cool the cooling load 17 together with the compression chiller 6, and the heat medium vapor is guided to the heat exchanger 7 to heat the heating load 18 or hot water supply equipment 19. Provides heat to the load.

In this way, the system is able to recover waste heat and use it effectively, but the cooling load is 17% compared to the amount of waste heat generated.
When the heating load 18 and the heating load such as the hot water supply equipment 19 are small, the absorption chiller 5 increases the apparent load with the bypass valve 16 to absorb excess heat and dissipate it into the air in the cooling tower 8. In order to prevent the heating load 18 and hot water supply equipment 19 from overheating, excess heat is dissipated into the air in the cooling tower 8 by a heat balancer circuit formed by a pipe 20.

In this way, with conventional methods, when the amount of waste heat generated is greater than the amount of heat required by the load, the surplus waste heat is wasted and dissipated without being utilized. When there is no heating load, all of the recovered heat is wastefully dissipated from the cooling tower 8, resulting in poor system thermal efficiency, which is disadvantageous economically, especially in small-scale power generation facilities.

The present invention eliminates the above-mentioned drawbacks of the conventional ones, and even when the amount of waste heat generated is larger than the amount of heat required from the load side, the surplus heat can be recovered and effectively used as electricity, and even small-scale power generation equipment can be efficiently and economically. The purpose of this invention is to provide a heat recovery device for a power generation facility that can be operated in a timely manner.

The present invention provides a power generation device that bears the power of an electric power load, a waste heat recovery device that recovers waste heat generated by the power generation device, and a cooling load that utilizes the recovered heat recovered by the waste heat recovery device. an absorption chiller that bears the same burden as the absorption chiller; a heating load heat exchanger that bears the heating load using the recovered heat; and a heating load heat exchanger that bears the heating load using the recovered heat; a compression refrigerator, in which the electric motor also serves as a generator, the compressor also serves as a turbine, and a heat exchanger that guides the recovered heat into a condenser and heats and evaporates the refrigerant liquid. The present invention, which is a heat recovery device for a power generation facility, is characterized in that it is equipped with a heat recovery device and is capable of recovering power, and will be described with reference to FIG. 2 with reference to an embodiment.

In Fig. 2, the constituent functions of the parts common to Fig. 1 are as follows.
It is similar to the one shown in the figure.

In the absorption refrigerator 5, the absorption solution in the generator 12 is heated by the heat medium vapor guided from the pipe line 11, and the refrigerant is evaporated.

The evaporated refrigerant gas enters the condenser 13, is cooled and condensed by the cooling water from the cooling tower 8, and is led to the evaporator 38 through the pressure reducing valve 49.

This refrigerant liquid falls on the cold water pipe 48 and partially evaporates,
The fallen condensate is also transferred to the cold water pipe 48 again by the refrigerant pump 45.
The cold water in the cold water pipe 48 is cooled by latent heat.

The evaporated refrigerant gas is absorbed by the absorption solution in the absorber 14, and is transferred to the generator 12 via the heat exchanger 47 by the solution pump 46.
sent to.

The absorption solution heated in the generator 12 to evaporate the refrigerant passes through the heat exchanger 47 and returns to the absorber 14 to the cooling tower 8.
The refrigerant vapor is cooled by the cooling water from the refrigerant, and refrigerant vapor is absorbed and circulated again, thus forming a refrigeration cycle.

Between the evaporator 38 of the absorption refrigerator 5 and the cooling load 17,
Cold water pipes 28 and 29 are provided for circulating cold water as a medium for conveying cold heat produced by the evaporator 38 to the cooling load 17.

A valve 30 is provided in the middle of the cold water pipe 28, and branch pipes 34 and 35 that connect to the evaporator tube 33 of the evaporator 31 of the compression refrigerator 6 are branched from both sides via valves 36 and 37. .

In the chilled water circuit, valves 30, 36, and 37 are opened and closed to change the route of chilled water depending on the size of the cooling load 17.

That is, when the cooling load 17 is small and only the absorption refrigerator 5 is operated, the valve 30 is opened and the valves 36 and 37 are closed.

When the cooling load 17 is a dog and the compression refrigerator 6 is to be used in addition to the absorption refrigerator 5, the valve 30 is closed and the valve 36.3 is closed.
Open 7.

In the example shown in Fig. 1, a heat exchanger for heat balance is provided in the heat exchanger 7 for heating load, but in the embodiment shown in Fig. 2, such a heat exchanger for heat balance is omitted. It's dark.

In the compression refrigerator 6, the compressor 25 is used as a turbine, the electric motor 26 is used as a generator, and the condenser 32 is provided with a heat exchanger 24.

The heat exchanger 24 includes a conduit 2 that branches from the heat medium conduit 11 that carries the heat recovered from the heat recovery device 2 and has a control valve 23.
2 is connected.

Valve 4L42, 43, 44 is cooling tower 39, circulation pump 40
This is a switching valve for a cooling water circuit having a cooling water circuit, and when the compression refrigerator 6 operates as a refrigerator, the valves 41 and 42 are closed, and the valves 43 and 44 are open.

To explain the power recovery effect of the compression refrigerator 6, when the amount of heat recovered from the heat recovery device 2 becomes surplus to the load such as cooling load or heating load, it is detected as an increase in pressure in the pipe line 11. , the valve 23 is opened and a portion of the heat medium is transferred to the heat exchanger 2.
Lead to 4.

If there is a surplus of recovered heat, the refrigerating action of the compression refrigerator 6 is of course unnecessary, so it is stopped.

Also, valves 30, 4L42 are open, valves 36, 37, 43, 4
4 is considered closed.

The condenser 3 is heated by the heat medium guided to the heat exchanger 24.
The refrigerant liquid in 2 evaporates and becomes refrigerant gas, which flows back into the casing 27, which drives the compressor 25 to rotate as a turbine, and the electric motor 26 acts as a generator to generate electricity, and the electric power can be recovered as motive power. .

In this case, the evaporator tube 33 has cooling water flowing through it and has a cooling effect, condensing the refrigerant gas.

The heat generated when operating the power generation equipment 1 consisting of a generator 3 and an electric motor 4 to obtain the required electric power is carried by exhaust gas, cooling water, cooling air, etc., and is transferred to a heat medium in a heat recovery device 2. It is moved and recovered to generate heat medium vapor.

During cooling or freezing, this steam is led to the absorption refrigerator 5 through the pipe 11, enters the generator 12, and is used as a heat source.
The liquid is returned to the heat recovery device 2 via the liquid receiver 21.

During heating and hot water supply, this heat-recovered steam is guided to the heat exchanger 7 and used for heating the heating load 18 or for hot water supply equipment 19.
It is used to make hot water for use, and is returned to the heat recovery device 2 via the liquid receiver 21.

9 is a circulation pump, 13 is a condenser, and 14 is an absorber.

First, the case where the cooling load 17 is less than the capacity of the absorption refrigerator 5 will be explained.

In this case, the valve 30 of the chilled water circuit is opened, the valves 36 and 37 are closed, and the chilled water is cooled only by the absorption refrigerator 5.

The compression refrigerator has stopped.

When the cooling load decreases, the steam consumption of the absorption refrigerator 5 is controlled and reduced, and the pressure within the pipe 11 increases.

This pressure rise opens the control valve 23 provided in the pipe line 22 and guides the excess steam to the heat exchanger 24 for power recovery.

The valves 41 and 42 are open, and the valves 43 and 44 are closed.

Upon receiving heat in the heat exchanger 24, the fluorocarbon gas in the condenser 32 evaporates, becomes high pressure, and flows back into the casing 27.

In this case, the compressor 25 functions as a turbine and rotates upon receiving the high-pressure fluorocarbon gas, which rotates the connected electric motor 25.
It can generate electricity as a generator and recover it.

With such a configuration, excess waste heat can be recovered and effectively used as electricity.

Next, considering the case that winter growth is an intermediate period, conventionally, the amount of waste heat from power generation equipment is generally larger than the amount required by the heating load, and the size of the heating load fluctuates. For this reason, heat balancers and the like were installed in the circuit, and excess waste heat was wasted into the atmosphere or water.

In addition, during the intermediate period, since the heating and cooling load for air conditioning was zero or very small, most of the waste heat from the power generation equipment was discharged into the atmosphere or water.

In contrast, in the system of this embodiment, as described above, surplus waste heat can be recovered and effectively utilized as electricity.

That is, excess waste heat is detected by the pressure increase in the pipe line 11, the control valve 23 is opened, the excess steam is guided to the heat exchanger 24, and power is recovered.

In this case as well, in the chilled water circuit, the valve 30 is opened and the valves 36 and 37 are closed, and even if there is a cooling load 17, the chilled water is cooled only by the absorption refrigerator 5.

In addition, although the amount of waste heat recovered from the power generation equipment 1 is smaller than the amount of heat required from the cooling load side to the absorption chiller, the amount of excess steam is so small that the compression chiller cannot be operated as a turbine generator. If it is surplus waste heat, pipe line 1
1, the bypass valve 16 of the absorption refrigerator 5 is opened, the bypass 15 connecting the condenser 13 and the absorber 14 is passed, and the refrigerant received in the condenser 13 is directly transferred to the absorber 14. and pour into the solution.

In this case, the heat given in the generator 12 by the recovered heat is given to the cooling water in the cooling water pipe in the absorber 14 as well as in the cooling water pipe in the condenser 13, and is dissipated in the cooling tower 8.

In this case, the surplus waste heat cannot be used effectively, but a dedicated heat exchanger (the lower heat exchanger 7 in Fig. 1) for discharging unbalanced heat as in the conventional No longer needed.

When the cooling load 17 is larger than the capacity of the absorption refrigerator 5 (
(including cases where the capacity of the absorption refrigerator 5 is small due to a small amount of recovered heat), in addition to guiding the heat medium vapor to the generator 12 and using it as a heat source to operate the absorption refrigerator 5, the compressor 25 is The compression type refrigerator 6 is operated as a compressor to bear part of the cooling load 17.

That is, in the chilled water circuit, the valve 30 is closed and the valves 36 and 37 are opened, and the chilled water is cooled by both the absorption refrigerator 5 and the compression refrigerator 6.

In this embodiment, an absorption refrigerator 5 and a compression refrigerator 6 are connected in series, and the absorption refrigerator 5 is provided on the upstream side (higher temperature side) of the chilled water system.

(1) As shown in FIG. 3, changes in the generated steam pressure caused by changes in the power load match well with the load characteristics of the absorption refrigerator.

(2) The economical efficiency of absorption refrigerators is greatly influenced by the cold water outlet temperature, and the size can be reduced by placing them on the high temperature side.

(3) When a load change occurs on the refrigerator set, since the control characteristics of the compression refrigerator are sensitive, the compression refrigerator is controlled first, and the amount of power generation increases or decreases accordingly, resulting in a self-balancing system. can be kept.

This is due to the following reasons.

According to the present invention, waste heat from power generation equipment is recovered and used to cover cooling and heating loads.If the recovered waste heat is insufficient for the cooling load, a compression chiller is used to supplement this, and the recovered waste heat is used to cover the entire load. If there is a surplus, it can be recovered as power, and fluctuations in the cooling load and fluctuations in the load on the power generation equipment can be balanced by simply combining a compression chiller and an absorption chiller without using special equipment. This makes it possible to reduce the running costs of power generation equipment based on the amount of recovered electricity, allowing even small-scale power generation equipment to use energy effectively.
It is possible to provide a heat recovery device for power generation equipment that operates efficiently and economically, resulting in an extremely effective practical effect in terms of energy saving.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a heat recovery system according to a conventional method, Fig. 2 is a block diagram of a heat recovery system according to an embodiment of the present invention, and Fig. 3 is a block diagram of a heat recovery system according to an embodiment of the present invention.
It is a graph showing the relationship between the power generation load and vapor pressure, and the absorption chiller load and vapor pressure. 1...Power generation equipment, 2...Heat recovery device,
Total: Generator, 4: Prime mover, 5:
...Absorption refrigerator, 6. ...compression refrigerator, 7.
...Heat exchanger, 8...Cooling tower, 9...
...Circulation pump, 10...Electricity load, 11.
-... Pipeline, 12-... Generator, 13...
... Condenser, 14 ... Absorber, 15 ...
...Bypass, 16...Bypass valve, 17...
...Cooling, freezing load, 18...Heating load,
19...Hot water supply equipment, 20...Pipe line, 2
1...Liquid receiver, 22...Pipeline, 23.
... Control valve, 24 ... Heat exchanger, 25.
-... Compressor, 26... Electric motor, 27...
...Casing, 28,29...Cold water pipe,
30...-1...Valve, 31...Evaporator, 32...
...Condenser, 33...Evaporator tube,
34.35-...branch pipe, 36°37...
Valve, 38...Evaporator, 39...Cooling tower, 40...Circulation pump, 41.42,43,4
4... Valve, 45... Refrigerant pump, 46
...Solution pump, 47...Heat exchanger,
48...-Cold water pipe, 49...Reducing valve.

Claims (1)

[Scope of Claims] 1. A power generation device that bears the power of an electric power load, a waste heat recovery device that recovers waste heat generated by the power generation device, and a system that utilizes the recovered heat recovered by the waste heat recovery device. an absorption chiller that bears the cooling load by using the recovered heat; a heating load heat exchanger that uses the recovered heat to bear the heating load; and a heating load heat exchanger that uses the recovered heat to bear the heating load; The compressor is equipped with a compression refrigerating machine that bears the load, and in the compression refrigerating machine, the electric motor is also used as a generator, the compressor is also used as a turbine, and the recovered heat is guided into a condenser to heat and evaporate the refrigerant liquid. A heat recovery device for power generation equipment, characterized in that a heat exchanger is provided and power recovery is possible.