JPH01127801A - Gas turbine exhaust-heat recovery boiler - Google Patents

Abstract

PURPOSE: To ensure a high volume of steam to be generated while saving supply water by disposing a post-stage economizer independently on the downstream side of exhaust gas from a prestage economizer and providing a bypass line coupling a gas turbine exhaust line and a boiler flue thereby keeping a high quantity of heat to be recovered from the boiler. CONSTITUTION: On the downstream side of exhaust gas from a prestage economizer 1b, a post-stage water supply line 3b branched from a prestage water supply line is coupled with a post-stage economizer 1c through a mixer 8. A gate valve V1 is closed while a water supply valve V3 and other valves C2 , C3 , V4 and V5 are opened thus separating the economizers 1b, 1c from each other. Independently from circulation I of return water of the economizer 1b, water at about 60 deg.C is passed at first through the economizer 1c and heated up to about 100 deg.C thence introduced through a recirculation line 9 to a water supply tank 3. It is then passed through the line 3b branched from the line 3a and returned back to the economizer 1c before being recirculated. According to the arrangement, heat can be recovered from gas turbine exhaust gas up to the temperature of about 100 deg.C. When heat demand of steam or hot water is low, steam generation is suppressed by discharging a part of exhaust gas through a boiler bypass line 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a gas turbine exhaust heat system that recovers the heat of the exhaust gas of a gas turbine that meets the demand for electricity and generates steam or hot water to meet the demand for heat. Regarding recovery boilers.

BACKGROUND ART A conventional gas turbine exhaust heat recovery boiler system like this will be explained based on FIG. 14. l' is an exhaust heat recovery boiler (hereinafter simply referred to as a boiler), 2' is a gas turbine,
3' is a water supply tank, 4' is a steam line, 5' is a makeup water line, 6' is a refrigerator, and 7' is a heat demand destination, which is a gas turbine directly connected to a generator 2a' and a compressor 2b'. The exhaust gas discharged from 2' was supplied to the inlet side of the boiler l' through an exhaust runner 10a'.

By passing the exhaust gas through the evaporator 1a' of the boiler evaporator and the energy saver lb' that is paired with the evaporator, the water supplied from the water supply tank 3' through the water supply line 3a' is first reduced in energy consumption. After being heated to a predetermined temperature in the evaporator tb', it is evaporated in the evaporator 1a', and the steam is sent from the steam line 4' to, for example, a refrigerator 6' disposed within the system or outside the system not shown in the figure. It was supplied and distributed to heat demand 7' such as space heating and hot water supply.

In addition, the steam that has been used in this way and has released heat, that is, the return water, is returned to the water supply tank 3' through each supply water return line 6a', 7a', and the supply water introduced into this water tank is sent to the heat demand destination. While making up for the shortage consumed in water line 7' with make-up water from make-up water line 5', the above-mentioned energy saver tb
' and was recycled to evaporator 1a'.

In this case, as an example, it was sent to the exhaust of the gas turbine 2' and turned into steam in the evaporator 1a'. The type of evaporator was freely chosen, such as water tube type or smoke tube type.

The generated steam is summer/process steam/cooling steam,
It was used for process steam and heating steam in the winter, and for hot water heating throughout the year.

For boiler make-up and steam consumption, make-up water was treated with a water softener 5a' and supplied, and boiler water quality was ensured with a chemical feeder 3b'.

If there is return water of process steam, heating steam, or hot water supply steam outside the return water area from the refrigerator 6', it is finally returned to the water supply tank 3' via the water supply return lines 6a' and 7a'.
The shortage of water was made up by the makeup water line 5'.

Problems to be Solved by the Invention The conventional gas turbine exhaust heat recovery boiler described above, however, has the following problems.

(Regarding the amount of water returned and its temperature.

During partial load operation of the refrigerator 6', the miscarriage of return water (drain water) was reduced, and at the same time, the drain temperature was lower than the rated temperature. Boiler 1' is rotated weekly with a constant evaporation amount, and refrigerator 6
When operating ' with partial load, the residual steam that is no longer used by refrigerator 6' is used as process steam outside the system.'
However, at the initial stage, residual water in the return water line 7a' returns to the water supply tank 3' as process steam return water, which lowers the water temperature of the water supply tank 3' together with the low-temperature drain water. If there is no return of process steam, make-up water (approximately 25° C. in summer) is supplied, and the temperature of the water in the constant water supply tank 3' is further lowered together with low-temperature drain water.

As a result, a decrease in the water temperature at the inlet of the economizer 1b' directly causes a decrease in the water temperature at the inlet of the evaporator 1a', resulting in a reduction in the amount of steam generated and deteriorating the exhaust heat recovery efficiency.

(2) Regarding the use of exhaust heat from gas turbines.

When the gas turbine 2' side uses clean fuel such as city gas 13A for combustion, the temperature of the exhaust gas released from the boiler l' to the atmosphere is approximately 100°C, which is the low-temperature corrosion prevention limit value.
It is possible to recover heat up to 1, but in reality the exhaust temperature is 1
Currently, heat recovery is only performed up to around 40°C, and the heat recovery gain of clean burning heat has not been effectively utilized.

(3) Regarding adjustment of steam amount.

If the total amount of steam is small, the partial load of the gas turbine 2' will be sufficient. However, gas turbine 2
In order to reduce the total amount of steam when a high load is required for 1', the steam generated in boiler 1' must be discharged into the atmosphere through a silencer without being input to the gas turbine. In the end, the make-up water used to obtain the surplus steam was wasted into the atmosphere.

Means for Solving the Problems In order to solve these conventional problems, the present invention provides the following:
The exhaust heat of the gas turbine is recovered to generate steam and hot water, which are passed through each steam line and hot water line to be used for the chiller inside the system or for heat demand outside the system, and then the return water is passed through the water supply return line. In the exhaust heat recovery boiler, which is introduced into the water supply tank through the exhaust heat recovery boiler, the above-mentioned pleural water supply line is connected to the exhaust gas downstream side of the front-stage economizer, which is paired with the boiler evaporator and connected to the water supply tank through the front-stage water supply line. A post-stage economizer is provided independently, which is connected to a post-stage water supply line that branches off from the mixer and is connected to the water supply tank via a recirculation line, and a recirculation line is provided on the outlet side of the post-stage economizer. and a pre-stage water supply line on the inlet side of the pre-stage economizer are connected via a gate valve, and a make-up water line branching from a water level adjustment line extending to the water supply tank is connected to the mixer, and a gas turbine and a boiler are connected. A bypass artificial damper valve is provided in the boiler bypass line that connects the exhaust line and the flue of the boiler, and a boiler inlet damper valve and a boiler outlet damper valve are provided in the exhaust line and the flue, respectively.

Therefore, by installing a post-stage energy saver, heat can be recovered from the gas turbine exhaust gas by expanding the range from about 140° C. to 100° C., so the amount of heat recovered from the boiler can be maintained at a high level. This is possible whether the front stage economizer and the latter stage economizer are used independently or in series.

In addition, when the refrigerator in the system, which has a large heat load as one of the heat demand destinations, becomes partially loaded, makeup water can be injected to supply steam to other heat demand destinations outside the system. The temperature of the water supply to the front-stage economizer decreases due to the increase and rise of water, because the water that passes through the front-stage water supply line connected to the front-stage economizer and the independent recirculation line connected to the rear-stage economizer is recirculated.
This can be prevented by increasing the temperature of the water supply in the water supply tank, ensuring a high amount of steam generated by the boiler.

Moreover, when the demand for heat such as steam and hot water is low, part of the gas turbine exhaust gas is discharged through the boiler bypass line and only the required amount is input to the boiler, thereby eliminating the need to generate unnecessary steam and replenishing it. You can save water.

EXAMPLE Hereinafter, an example of the present invention will be explained with reference to FIGS. 1 to 12. FIG. 1 shows the basic system of the waste heat recovery boiler, the area around the water supply tank, and the heat demand outside the system. The downstream side of the exhaust gas of the front-stage economizer 1b connected to the front-stage water supply line 3a that is paired with the evaporator la of the boiler l and extends from the water supply tank 3 is connected to the rear-stage water supply line 3b branched from the front-stage water supply line. is connected to the inlet of the latter-stage economizer IC via the mixer 8.

Then, a recirculation line 9 with a water tank temperature control valve Ci installed in the middle is connected between the outlet of the rear stage economizer IC and the water supply tank 3, and is arranged independently from the front stage energy saver 1c. This recirculation line is connected to the pre-stage water supply line 3a via a gate valve V.

In addition, the water supply temperature adjustment valve C for the rear stage energy saver! A make-up water line 5 with a water level adjustment valve Cs provided in the middle is connected to the mixer 8, and a water level adjustment line 5a is branched from the middle of the make-up water line to a water tank with a water level adjustment valve Cs in the middle.

On the other hand, the boiler 1 population side exhaust line 10 of the gas turbine 2
A boiler bypass line 10 is provided with a bypass artificial damper valve DI in the middle between a and the boiler l outlet flue fob.
In addition, a boiler inlet damper valve and a boiler outlet damper valve are arranged in the exhaust line 10a and the flue 10b, respectively.

In the figure, 11 indicates the (process) hot water line, and other control system valves include C4, boiler water level adjustment valve, and C4.
, is a refrigerator steam flow rate adjustment valve; C6 is a refrigerator steam cutoff valve;
is the water supply valve for the rear stage energy saver, ■4 is the water supply valve for water level adjustment, V is the water supply valve for the mixer, ■ is the process hot water supply valve, and ■,
is the boiler stop valve.

Next, its effect will be explained.

Item (1) First, the gas turbine exhaust gas is reduced to approximately 140
In order to recover heat from 100°C to a low temperature of 100°C, an explanation will be given based on Figures 2 to 4. Figure 2 shows the evaporator 1a.
3 shows a case where the front-stage economizer 1b is used alone (the latter-stage economizer 1c is stopped), the gas turbine exhaust heat is recovered, and the entire amount of generated steam is consumed as steam for the refrigerator 6. Figure 4 shows the case where the post-stage economizer 1c is used independently of the evaporator 1a and the pre-stage economizer tb, and the heat is consumed by the heat demand destination 7 both inside and outside the system. The case is shown in which all the heat transfer tubes of the coalizer 1b and the post-stage economizer 1c are used in series, and the heat demand destination 7 mainly consumes process steam, and the water supply lines 3a and 3b are connected to the heat demand destination 7. The selection shall be made as appropriate depending on the usage. Practically speaking, a system as shown in Fig. 3 for summer and Fig. 4 for winter is appropriate.

In addition, the switching valves V, V, of the water supply lines 3a, 3b,
.

Although V is used as a manual valve, it is of course possible to use an automatic valve if the valve is operated frequently or remotely.

The above contents can be summarized as shown in Table 1.

First, in the operation shown in Fig. 2, the sluice valve VI% subsequent stage energy saver water supply valve V and other valves C, , C, , v, , v are closed, and the energy savers 1b and Ic are cut off. As a result, the generated steam enters the refrigerator 6 from the evaporator 1a via the steam line 4, becomes return water, is introduced into the water supply tank 3 via the water supply return line 6a, and is further introduced into the water supply tank 3 via the pre-stage water supply line 3a. It is returned to the pre-stage economizer 1b, and the above line (hereinafter referred to as
(referred to as circulation ■). In this case, as shown in Fig. 5, the return water (drain water) from the refrigerator 6 has a temperature of around 95°C in the water supply tank 3, and at this set water supply temperature of about 95°C, the gas turbine exhaust gas Heat can be recovered up to a temperature of approximately 140°C, which is the design point (
This is a basic system that is established only in the case of (Base Full).

Therefore, for example, when using a dual fuel system that co-combusts kerosene and light oil based on city gas, this system is used to prevent sulfuric acid corrosion. However, up to this stage, the above-mentioned drawbacks cannot be avoided.

Next, in the operation shown in FIG. 3, the gate valve vl is closed, and the subsequent stage economizer water supply valve Vs and other valves Ct, C,, V, are closed.

(2) By opening the valve and making the front-stage and rear-stage economizers 1b and Ia independent, the supply water at around 60°C is initially After heating the water to around 100°C through the latter stage economizer 1c, the water is introduced into the water supply tank 3 via the recirculation line 9,
The water supply line 3b branches from the water supply line 3a in the previous stage, returns to the water pipe 1c in the latter stage, and the above line (hereinafter referred to as
(referred to as circulation ■).

As the recirculation is repeated, the temperature inside the water supply tank 3 is maintained at approximately 90 to 95°C. On the other hand, when the water supply temperature at the inlet of the post-stage economizer 1c is 60°C, the gas turbine exhaust temperature is maintained at approximately 100°C. It is possible to recover heat up to a temperature of . In this case, the system is applied when a partial load or full load is applied to all of the steam and hot water heat demand destinations 7 including the refrigerator 6 listed in Table 1 above.

Therefore, as shown in FIG. 6, the amount of heat Q absorbed from the gas turbine exhaust gas in the post-stage economizer 1'c is determined by the fact that water is always supplied to the post-coal economizer 1c from the make-up water line 5 through the mixer 8. (Circulation (2)) is easy to control because it can be ensured independently of the steam generation system of the pre-stage economizer 1b, that is, the circulation (2).

In the figure, the amount of heat Q recovered per gas turbine exhaust gas up to 100°C in the post-stage economizer 1c is the amount of heat Q in the system of the refrigerator drain water (return water), and the steam (condensate) and temperature are consumed. If the extra-system heating amount q of make-up water equivalent to the insufficient return water is operated to the maximum regardless of circulation ■, that is, Q =
System efficiency can be maximized when ql+Qt.

Here, Table 2 summarizes temperature examples of each fluid in this system.

Table 2 Therefore, the predetermined pressure (for example, 9 Ky/cm
9), the water whose pressure is increased by the water supply pump 3C provided in the middle of the front-stage water supply line 3a is supplied and distributed to the front-stage and rear-stage energy savers 1b and lc, respectively.

When supplying water to the latter stage energy saver 1c, the mixer 8
Although the temperature is adjusted to 60°C as described above by mixing it with make-up water in advance in the tank, if the amount of make-up water from the make-up water line 5 by the post-stage coal saver feed water temperature control valve C2 is insufficient, -
- Supplement by adjusting the water level of the water tank with the water tank water level adjustment valve C5 of the water level adjustment line 5a branched from this make-up water line 5. The temperature of the water in the second-stage energy saver 1c is raised to about 95° C. by the exhaust gas, and then recirculated to the water supply tank 3. This hot water is allocated and used as hot water for hot water supply, water tank heating water, etc. as needed.

It is also possible to separately supply process hot water from the water supply tank 3 through the (process) aL water cylinder line 11.

Further, the relationship between the generated steam and the circulating water (return water) in the circulations I and H is summarized in Table 3, taking the case of the refrigerator 6 as an example.

- On the other hand, in the operation shown in FIG.
+ V, open one of them, and open the front stage energy saver water supply valve V.
In addition, since this system is mainly implemented in winter, the control valves cl and Cs around the refrigerator are also closed. Connect all heat exchanger tubes in series.

In this case, as shown in FIG. 1, the water supply tank 3 is routed from the post-stage economizer 1c via the recirculation line 9 (circulation ■), which consumes the amount of heat Q' absorbed from the gas turbine exhaust gas in the post-stage economizer 1c. In-system heating It q t ' of the return water flowing to the refrigerator 6 and process hot water (Va, the external heating amount q of make-up water equivalent to the insufficient return water that is consumed outside the system when closing/closing Va), ′, the amount of heating in the system of the former return water Q+′
Since the circulation (■) is recirculated, it can be ensured independently of the steam generation system of the pre-stage economizer 1b, that is, the circulation from the steam line 4 to the outside of the system (indicated by the circulation (■ in the figure)).

During the opening and closing operations of the various valves, make-up water can be introduced into the water tank 3 through the water level adjustment line 5a or into the mixer 8 through the make-up water line 5, depending on the setting of the make-up water temperature. The make-up water will be heated in the container 8.

That is, the makeup water temperature is adjusted as shown in Table 4.

Table 4 Item (2) Next, to explain another example of the above item (1), Fig. 8 shows an example of temperature control of the steam/water supply system. Although the system used has been cited, the present invention is not limited to this, and can also be applied to a system that uses superheated steam by disposing a superheater 1d upstream of the evaporator 1a and a temperature control valve C9 in the superheater. It goes without saying that it can be done.

In addition, the boiler L is smoke tube type or water tube type (deaerator internally sealed or not)
It can be of any format, including

(Calorific value of the steam at the inlet of the second stage economizer 1c.

The post-coal economizer bypass temperature control valve C6 is effective in always controlling the post-coal economizer outlet water to a predetermined value (for example, 95° C.) in response to changes in temperature. Note that 12a is a first auxiliary combustion burner, and 12b is a second auxiliary combustion burner.

Item (3) On the other hand, when the demand for heat such as steam or hot water is low, an operation is performed to release part of the gas turbine exhaust gas through the boiler bypass line IO. Explaining based on FIGS. 9 and 10, regarding the control of the steam generation amount of the boiler 1, FIG. 9 shows control when the consumed steam for the heat demand 7 outside the system consumes all the surplus steam inside the system. , Figure 10 shows control when the amount of steam consumed outside the system changes each time and the amount of steam supplied is increased or decreased in response to pressure fluctuations so that the steam header pressure remains constant. A valve C8 and a blowoff valve CIO are provided on the steam line 4. In the former case, the boiler 1 only needs to generate the maximum steam corresponding to the gas turbine 2 load, so the steam pressure control valve C8 is used to properly adjust the source pressure, and the blow-off valve CIO is operated until the steam conditions are established at the beginning of boiler 1 startup. An ON/OFF valve is used to release air. In addition,
Also possible as a manual valve.

On the other hand, in the latter case, the steam is controlled properly at the outlet (downstream side), and the air discharge is controlled to occur at the drum height. Also,
When the steam source pressure becomes higher than a predetermined value, the bypass artificial damper valve is opened under the control of the control device 13, and the boiler inlet damper valve D! Perform remote manual operation to close.

The order of control is (a) gas turbine 2
The load is set to electric power demand, and (b) when the exhaust heat amount of the gas turbine 2 is higher than the steam demand, the control device 13 limits and lowers the amount of heat flowing into the boiler I.

Furthermore, as a common function of the former and the latter as mentioned above, the control device 13 is configured to start the gas turbine 2, fully open the gas turbine 2, fully open the control valves D, and fully close the gas turbine 2 to stabilize the gas turbine 2 at a predetermined load. After that, fully open D3 and D.

It is equipped with a remote manual operation, a sequencer (not shown), etc. for closing D and opening D.

In addition, the bypass inlet damper valve and the boiler inlet damper valve are automatic valves, but (a) they can be individually operated valves and electrically interlocked, or (b) they can be connected by links, so that they can be mechanically improved. Take measures such as connecting them.

On the other hand, the boiler outlet damper valve may be either an automatic valve or a manual valve, and essentially only needs to ensure complete closure (shielding).

Item (4) Furthermore, to explain another embodiment of item (3), as shown in FIG. 11, a damper consisting of one valve body is used instead of the boiler bypass artificial valve D1 and the boiler inlet damper valve. It is also possible to provide a valve D4 to have a function of distributing the flow rate of the gas turbine exhaust gas.

2 Item (5) Regarding an actual system example applied under such a configuration, Fig. 12 shows the details of the heat demand destination, in addition to the refrigerator 6, 14 is a process, and 14a is a process Boiler, 15a is steam heating (fan coil unit), t
sb is a hot water heater, 16a is a steam heat exchanger, tab is a hot water heat exchanger, 14b is a process steam header, 14
c is a header for process recycled water, 17a is a (cogeneration) hot water header, and 17b is a header for (cogeneration) recycled water. In particular, the process steam header 14b is connected to the downstream side of the steam line 4 via a steam control valve C8. are doing. These components such as the refrigerator 6, heaters 15a and 15b, steam 16a and hot water supply 16b are arranged upstream of the steam control valve C8, so their momentary consumption is subtracted from the steam generated by the boiler. The steam generated by the boiler is controlled so that the remaining steam (hot water) matches the amount required for the downstream process.

To briefly explain the respective flows of steam and hot water, first, in the use of steam, the steam is used within the system for the refrigerator 6, and outside the system, it passes through the steam line 4 to the process 14, heating 15a, 15b and steam.

At this time, (a)' Process steam is once collected in the steam header 14b together with steam from other process boilers 14a and discharged to the process 14. In the process, in addition to heat recovery, a portion of the steam is consumed and the rest is returned to the water supply header 14c as water supply. Furthermore, this recycled water (cogeneration system component) is returned to the recycled water header 17b, and the consumed recycled water, that is, the steam sent to the process steam header 14b and the return steam to the process steam header 14c (
Supply water into the system for the difference between hot water and hot water.

(b) Heating steam is supplied to the fan coil unit 15a, and drain water is introduced to the water supply header 17b via a hot well tank (not shown).

(c) Hot water for hot water supply is first secured in the steam heat exchanger 16a, and drain water is introduced into the return water header 17b.

Next, in the use of hot water, hot water is supplied from within the system, that is, hot water is supplied from the hot water supply line lla and the process hot water line 11, and after the process hot water is collected together with the hot water obtained in the steam heat exchanger 16a in the hot water header 17a, ( b) The hot water from the hot water header 17a is used as a heating source to raise the temperature of tap water in the hot water heat exchanger tab and is used for hot water supply. Recirculate.

(b) Then, the hot water whose temperature has been lowered by the hot water header 17b is
The water passes through the hot water heater 15b and is collected into the water supply header 17b.

(c) Thereafter, the water in the water supply header 17b is introduced into the water supply tank 3 as return water through the supply water return water line 7a, and is subjected to a process of being recirculated.

Finally, a general example of the overall cogeneration system including the gas turbine exhaust heat recovery boiler according to the present invention described above is shown in FIG. 13, and the main specifications in this case are summarized in Table 5.

Table 5 In the figure, 5a is a water softener, 5b is a makeup water tank, 5c is a makeup water supply pump, 18 is a seal gas discharge pipe, 19 is a dump steam discharge silencer, 20 is an accumulator, and 21 is a fuel gas compressor. 6a is a cold water supply pump, 6b is a cooling water supply pump, llb is a process water supply pump, 22 is a chimney, and 23 is a cooling tower.

Effects of the Invention As detailed above, according to the present invention, (1) steam generation in the boiler is improved by keeping the water temperature of the water supply tank at a constant value using the water temperature at the outlet of the downstream economizer, for example (95°C) as a heating source; It is possible to maintain a high amount of heat recovery and heat recovery.

(2) The water temperature in the water tank is always approximately 95℃ when using a refrigerator.
When the refrigerator is not in use, the temperature is controlled at, for example, about 60°C. Furthermore, when the refrigerator is in use, the boiler evaporation amount and heat recovery amount can be increased by controlling the feed water temperature to a similar temperature of 60° C. at the inlet of the latter-stage economizer. When the refrigerator is not in use, the front and rear economizers are connected, ensuring a large total heat transfer area for the economizers.

(3) By providing a boiler bypass line, the amount of steam supplied can be freely adjusted in the range of 0 to ioo% according to the opening degree of each damper valve, and the amount of make-up water can also be controlled to only the necessary amount.

(4) In addition, when Dual Fuel (that is, city gas containing kerosene, diesel oil, etc.) is used in a gas turbine, it contains some sulfur, so the front stage economizer must not be operated alone from the viewpoint of sulfuric acid corrosion. (See Figure 2) When a single sulfur-free fuel is used in a gas turbine, the front-stage economizer and the post-stage economizer are operated independently from the viewpoint of efficient recovery of gas turbine exhaust heat. (Refer to Figure 3) or operation with a series of front and rear stage economizers (Refer to Figure 4). This can be easily handled by simple switching operations of control valves and valves.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram showing an example of a gas turbine exhaust heat recovery boiler according to the present invention, Fig. 2 is a configuration diagram showing a system using a front-stage economizer alone, and Fig. 3 is a diagram showing a system using the front-stage and rear-stage economizers. Fig. 4 is a block diagram showing a system in which the front stage and rear stage economizers are used in series. Figures 5.6.7 are the second
．． Figure 3.4 shows the relationship between gas turbine exhaust temperature and boiler generated steam/feed water temperature for each system, and shows how to control the amount of steam generated using damper valves installed in the bypass line, exhaust line, and flue. FIG.
FIG. 1 is a main part configuration diagram showing another embodiment of FIGS. 9 and 10. FIG. 12 is a system diagram showing an example of a heat demand destination and its component equipment, and FIG. 13 is an overall configuration diagram showing a general example of a cogeneration system including a gas turbine exhaust heat recovery boiler according to the present invention. FIG. 14 is a schematic configuration diagram showing an example of a conventional gas turbine exhaust heat recovery boiler. l...Boiler, 1a...Evaporator, lb...Pre-stage economizer,
1c...Late stage energy saver, 2...Gas turbine, 3...Water supply tank, 3a...Front stage water supply line, 3b...Late stage water supply line, 4...Steam line, 5...Makeup water line, 5a...
・Water level adjustment line, 6.. Refrigerator, 6a, 7a.. Water supply return line, 7.. Heat demand destination, 8.. Mixer, 9.. Recirculation line, IO.. Boiler bypass line, 10a
...Exhaust line, tab...Flue, 11...(process) hot water line, VL...Gate valve, Dl...Bypass artificial damper valve, D,...Boiler inlet damper valve, D,...Boiler outlet damper (1 other person) Figure 2 Figure 63 Figure 4 Figure 6 Figure 11

Claims (1)

[Claims] The exhaust heat of the gas turbine is recovered to generate steam and hot water, which are passed through each steam line and hot water line to be used for the chiller inside the system or for heat demand outside the system, and then the return water is passed through the water supply return line. In the exhaust heat recovery boiler, the exhaust gas is introduced into the water supply tank through the front water supply line, on the downstream side of the front stage energy saver, which is paired with the boiler evaporator and connected to the water supply tank via the front water supply line. A post-stage economizer is provided independently, which is connected to a post-stage water supply line that branches off from the mixer and is connected to the water supply tank via a recirculation line, and a recirculation line is provided on the outlet side of the post-stage economizer. and a pre-stage water supply line on the inlet side of the pre-stage economizer are connected via a gate valve, and a make-up water line branching from a water level adjustment line extending to the water supply tank is connected to the mixer, and a gas turbine and a boiler are connected. A gas turbine exhaust heat system in which a bypass inlet damper valve is provided in the boiler bypass line that connects the exhaust line and the boiler flue, and a boiler inlet damper valve and boiler outlet damper valve are provided in the exhaust line and the flue, respectively. recovery boiler.