JPS58162706A - Feed water supply device for multiple pressure type combined electric generator - Google Patents

Abstract

PURPOSE:To allow a single unit of pump to perform a feed water supplying operation and to remove a flush which can take place at an area close to a suction port of the pump, by extracting a water of intermediate pressure from an intermediate stage of one type of feed water pump and by supplying such a water into a waste heat recovery boiler as a feed water other than a maximum pressure water. CONSTITUTION:A multi-stage feed water pump 18 has its delivery port 18a of final stage connected with a high pressure drum 9 via economizers 19, 7 for a high pressure zone and a high pressure feed water valve 8. An extraction outlet 18b of an intermediate stage is connected with a low pressure drum 5 via an economizer 3 for a low pressure zone and a low pressure feed water valve 4. A suction inlet 18c of feed water pump 18 is connected with a condenser 1. Since one type of feed water pump 18 can supply the feed water both to the high pressure drum 9 and the low pressure drum 5, money investment for equipments are greatly saved. Moreover, the feed water pump 18 can suck a low temperature condenser outlet water directly from the condenser 1 and therefore a risk of causing a flush at a suction port can be got rid of.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water supply device for an exhaust heat recovery boiler in a double pressure combined cycle power generation facility.

FIG. 1 shows an example of a system configuration of a conventional double pressure type combined cycle.

The condensate in the condenser 1 is sucked into the condensate pump 2, reduced to zero pressure, and heated by the low pressure economizer 3 of the exhaust heat recovery boiler. 2
' is supplied by a backup condensate pump installed in accordance with safety standards.

Low pressure section carbon saving! A part of the feed water heated in a3 is fed to the low pressure drum 5 via the low pressure water feed valve 4.

The remaining water supplied from the low-pressure section economizer 3 is further boosted in pressure by the water supply pump 6, and is supplied to the high-pressure drum 9 via the high-pressure section economizer 7 and the mid-pressure water supply valve 8.

6' is a water supply pump installed in accordance with safety standards and used as a backup.

The water stored in the low-pressure drum 5 is convectively circulated to the low-pressure evaporator 10 due to the difference in specific gravity between cold water and hot water, heated by heat exchange with exhaust gas, evaporated and returned to the low-pressure drum 5, and then passed through the low-pressure main steam pipe. 11 and a low pressure regulating valve 12'id to be sent to the steam turbine 17 to drive it and rotate the main electric machine G.

The water stored in the high-pressure drum 9 is evaporated in a high-pressure evaporator 13 and sent to a steam turbine 17 via a high-pressure superheater 14, a high-pressure main steam pipe 15, and a high-pressure control valve 16 to drive it.

The above is the pressure part economizer 7, high pressure drum 9 and high pressure evaporator 1.
About a double pressure type double pressure combined power generation facility that consists of two systems: a high pressure heat recovery system consisting of 3 etc., and a low pressure heat recovery system consisting of a low pressure section economizer 3, a low pressure drum 5, a low pressure evaporator 1O etc. As explained, high pressure, medium pressure,
There is a post-pressure combined generator' facility that consists of three low pressure systems, and a double-type combined generator'vt facility that similarly consists of four systems: high pressure, Nakajima pressure, Nakado, and low pressure.

Although the above-mentioned co/pound cycle power generation equipment has the advantage of high thermal efficiency, it has the disadvantage of high equipment cost and maintenance management cost due to the large number of auxiliary equipment.

In the case of an i-pressure combined power generation facility with two cylinder and low-pressure systems as in the above example (Fig. 1), including the spare pump,
If a total of 4 pumps, 2 condensate pumps and 2 water supply pumps, are to be installed for one steam turbine shaft, and n systems with different generated steam pressures are constructed, 2n water supply systems will be required. It is necessary to install a pump for The fact that a large number of water supply pumps are required to be installed is also one of the reasons for the above-mentioned disadvantage of having a large number of auxiliary equipment.

In addition, the water supply pump 6 in the example shown in FIG. 1 is configured to suck in high-temperature supply water heated by the low-pressure section economizer 3, so that it is flushed at the pump inlet in a transient state when the load suddenly changes. Easy to occur. This is also a technical problem common to conventional double pressure combined power generation equipment.

The present invention has been made in view of the above circumstances, and its purpose is to provide a double-pressure combined power generation facility that recovers heat from exhaust gas as steam at the pressure of multiple foods.
To provide a water supply device that can supply water with one type of pump per steam turbine and is free from the risk of flash occurring near the pump population.

The principle of the present invention is to install one type of multi-stage high-pressure water supply pump that meets the requirements of a high-pressure heat recovery system, and extract water at the required pressure, such as medium-high pressure, medium pressure, or low pressure, from the intermediate stage. By supplying this to the exhaust heat recovery system of each pressure, the water supply pumps are consolidated into [Type 1].

The fact that the principle of the present invention described above can be practically applied is as follows when examined from the relationship between the required pressure of water supply and pump performance.

FIG. 2 is a chart showing the evening bin load and water supply pressure in the double pressure type double pressure type combined power generation equipment shown in FIG. 1.

Curve ptVi indicates the low-pressure side system pressure, and is the required pressure to supply water to the low-pressure drum 5 in FIG.
The specific value of , is 4 to 5 atg.

In the conventional water supply system shown in Fig. 1, the turbine load is 10
In order to obtain the above pressure p1 at 0%, the pressure characteristics of the condensate pump 2 in Fig. 1 are set as PL. Reduce pressure by effect.

As before, the curve pk shows the high-pressure side system pressure, which is the required pressure to feed the high-pressure drum 9 in FIG. In conventional equipment, the pressure p! at the point where this curve p- intersects with the 100% turbine load line. The discharge pressure characteristic of the water supply pump 6 is set as P- so that
In the figure, the differential pressure corresponding to the section 9 shown with tuching is reduced by the effect of the high-pressure water supply valve 80 and the throttle 9.

Referring to FIG. 1, as a reminder, the water supply pump 6 sucks the condensate that has been pressurized to the curve PL by the condensate pump 2 and increases the pressure to the curve Ph by 8 ports.

The specific value of the pressure p is 50 to 60 atg.

In the conventional technology, as described above, the condensate pump 2
The condensate was fully pressurized to the curve P□ in the vsz diagram, and the pressure was further increased to the curve P1 by the water supply pump 6, but it is of course possible to pressurize the condensate to the curve Ph with a single pump.

As the one pump, for example, the rating is 1100a.
When using a five-stage pump of t, a pressure of 20 atg can be obtained by extracting from the first intermediate stage, so it is technically possible to reduce the pressure to the curve pL using a throttle valve.

Based on the above principle, steam turbine, v1s per bottle shaft
In order to achieve the object of the present invention, which is to construct a water supply system for a double-pressure combined power generation equipment using similar water supply pumps and to prevent flushing, the present invention provides a water supply system for multiple types of water supply pressures in a lateral pressure combined power generation equipment. The system is characterized in that it is equipped with a water feed pump that satisfies the specifications for the highest pressure, extracts water at an intermediate pressure from the intermediate stage, and supplies this water to the exhaust heat recovery boiler as water at a pressure other than the highest pressure. do.

To my friend, the one type of pump mentioned above means one pump, excluding the spare pump.

Next, an embodiment of the present invention will be described with reference to FIG. In this figure, the same drawing reference numerals as in FIG. 1 refer to similar or similar components to those in FIG. 1 (prior art device).

18 is a multistage water supply pump provided by applying the present invention,
It has a final stage discharge port 18a and an intermediate stage extraction port 18b. The rated pressure of this multi-stage water supply tank 18 is set to be equal to or significantly higher than the required water supply pressure of the high-pressure drum 9, and the extraction pressure of the intermediate stage is set to be equal to or slightly higher than the required water supply pressure of the low-pressure drum 5. Set to . 18' is a backup water pump.

The discharge port 18m of the final stage of the water supply pump 18 is connected to the high pressure drum 9 through the high pressure section economizer 19, the same 7, and the high pressure water supply valve 8t.
Connect to. Then, the intermediate stage extraction port 18b is connected to the low pressure drum 5 via the low pressure section economizer g7h and the low pressure water supply valve 4.
Connect to. The suction port 18c of the water supply pump 18 is connected to the condenser 1
Connect to.

Next, the operation of the water supply system for the nine double pressure combined power generation facilities constructed as described above will be explained.

The water supply pump 18 sucks the condensate in the condenser 1.
(Discharged from the final stage discharge port 18a and intermediate stage extraction port 18b.

From the final stage discharge port 18a, water with a pressure equal to or higher than the required water supply pressure of the high-pressure trim 9 is discharged, so this is appropriately throttled with the high-pressure water supply valve 8 to the required water supply pressure according to the turbine load. It is depressurized and supplied to the high pressure drum 9. The water supplied to the high pressure drum 9 is supplied to the high pressure part economizer 19
The water is heated in the water tank 7, the pressure is regulated by the high-pressure water supply valve 8, and the water flows into the high-pressure drum 9 to be stored.
The steam turbine 17 is driven in the same manner as in Fig. 11).

In addition, since the intermediate stage extraction port 18b of the water supply pump discharges water at a pressure equal to or higher than the water supply pressure required for the low pressure drum 50, this is appropriately throttled by the low pressure water supply valve 4 and adjusted according to the turbine load. The water is depressurized to the required water supply pressure and supplied to the low pressure drum 5.

The water supplied to the low-pressure drum 5 is heated by the low-pressure part economizer 3, the pressure is regulated by the low-pressure water supply valve 4, and flows into the low-pressure drum 5 to be stored.After that, in the conventional device (Fig. 1) K. The steam turbine 17 is driven in the same manner.

As explained above, in this embodiment, the high-pressure drum 9 and the low-pressure drum 5 are
water supply is possible. In this way, the two types of pumps (condensate pump 2 and water supply pump 6 in the example in Figure 1) that were conventionally used as water supply devices for double-pressure type double-pressure combined power generation equipment are consolidated into one type of pump. This not only reduces the equipment cost of the pump, but also simplifies the electrical system, piping, care, and control means attached to the pump, significantly reduces equipment investment, and improves operability and maintainability. Improved.

The embodiment shown in FIG. 3 is one in which the present invention is applied to a water supply system for a double pressure combined power generation facility that has two exhaust heat recovery systems, one high pressure and one low pressure. Therefore, the present invention can also be applied to a water supply device of a double pressure combined power generation facility having three or more exhaust heat recovery systems.

In particular, the water supply pump 6 in the conventional device shown in Figure 181 sucks condensate heated to about 1,500 ℃ by the low-pressure section economizer 3, so it is necessary to flush near the suction port due to sudden changes in load. However, as can be seen from the embodiment of the present invention shown in Fig. 3, the water supply pump according to the present invention (18 in this example) Since the low-temperature condenser outlet water is directly sucked from the vessel, there is no strain that would cause 7 lashes at the suction section.

As explained above, the present invention provides one type of water supply pump that satisfies the specifications of the highest pressure among multiple types of water supply pressures in a double-pressure combined power generation facility, and extracts water at an intermediate pressure from an intermediate stage of the water supply pump. By supplying this water to the exhaust heat recovery boiler as water other than high pressure water, it is possible to supply water with one pump per steam turbine in a double pressure combined power generation facility. This has an excellent practical effect in that there is no ugliness caused by flash.

[Brief explanation of the drawing]

Figure 1IAI is a steam system diagram of a conventional double-pressure combined power generation facility, Figure 2 is a diagram showing the relationship between the main turbine load factor and water supply pressure in a double-pressure combined cycle, and Figure 4 and @3 are steam system diagrams of a conventional double-pressure combined cycle. It is a 4-gas system diagram of an embodiment of a water supply device for a pressure-type CO/NOKUI/DO power generation facility. l...Condenser, 2...Condensate pump, 3...Low pressure section economizer, 4...Low pressure water supply valve, 5...Low pressure trim, 6
...Water supply pump, 7...High pressure section TDR coal generator, 8...
- High pressure water supply valve, 9... High pressure drum, 17... Steam turbine, 18... Water supply pump, 18a... Same final stage discharge port, 18b... Same middle stage extraction port, 19...・Thermostatic section energy saver. Agent: Patent attorney Masamikatsu Akimoto, 20! -1:N hair correction%

Claims (1)

[Claims] 1. In a double-pressure combined power generation facility in which the thermal energy contained in the exhaust gas of a gas turbine is recovered as steam at a pressure of several degrees by an exhaust heat recovery boiler, and this steam is used to drive a steam turbine, the above-mentioned A water supply pump compatible with the exhaust heat recovery boiler 2 that generates steam at the highest pressure among multiple pressures is installed, and medium-pressure water is extracted from the intermediate stage.
This is configured to be supplied as water to the exhaust heat recovery boiler that generates steam at a pressure other than the highest pressure, and it is possible to supply water to multiple exhaust heat recovery boilers in a double pressure combined power generation facility using one type of water supply device. Water supply system for double pressure combined power generation equipment.