JPS6269005A - Method of controlling temperature of turbine bypass desuperheater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides high-pressure
This article relates to a noise control method for a turbine bypass tank that controls high-temperature steam to water at an appropriate temperature.

[Conventional technology]

For general steam turbine equipment, a turbine bypass cooling device is adopted. Turbine bypass temperature reduction equipment allows steam to flow directly from the steam generator to the condenser when the power system does not require much electricity or when the steam pressure and temperature have not reached a specified level such as during startup. In this system, cooling water is added to relatively high-pressure, high-temperature steam from a steam generator, and water at an appropriate temperature is passed to a condenser. The reason for flowing water at an appropriate temperature into the condenser is to prevent permanent thermal deformation in the structure of the condenser.

By the way, recently, the adoption of so-called combined cycle power generation, which combines gas turbine equipment and steam turbine equipment, has become active in Japan. There is a trend towards adopting turbine bypass detemperature devices, taking into consideration the waiting period until temperatures reach 30 degrees. That is, the sixth
The figure is a schematic example of a typical combined cycle power generation system, and this equipment is roughly divided into gas turbine equipment, exhaust heat recovery equipment, and steam turbine equipment.

As shown in the diagram, the gas turbine equipment includes a compressor (1), combustion! (2), a gas turbine (3),
The air sent out at high pressure from the compressor (1) is added with fuel in the combustor (2), and reaches the gas turbine (3) as high-temperature gas. After doing work here, the exhaust gas is sent to the exhaust heat recovery equipment. I'm trying to send it. The waste heat recovery equipment has a vertical waste heat boiler (6), and inside the waste heat boiler (6) there are a coal saver (7), an evaporator (7a),
(7b) A superheater (9) is arranged along the barrel axis, and in particular the evaporator (7a) is provided with a drum (8). The supplied water sent to the economizer (7) is preheated here and further sent to the evaporator (7a).

The steam leaving the evaporator (7a) is separated into water and steam in the drum (8), and the steam is again sent to the superheater (9), where it is sent as dry steam to the steam turbine equipment. .

The steam turbine equipment has a main steam pipe (12a) and a turbine bypass pipe (12b). The former is a steam control valve C
The latter is connected to the steam turbine (5) via the steam turbine (5), and the latter has a turbine bypass valve (13, a desuperheater α), a cooling water valve (0), and is connected to the condenser Ii. (
5) and the gas turbine (3) are interposed with a generator αa connected by a common shaft. -The dry steam leaving the superheater (9) of the waste heat boiler (6) is flow controlled by the steam control valve (121) and reaches the steam turbine (5), where the expansion of the steam causes the generator I The steam leaving the steam turbine (5) is cooled in the condenser α1, passes through the pump (11) as condensate, and one side is sent to the economizer (7) of the waste heat boiler (6). , and the other is sent to the cooling water valve 3 of the turbine bypass temperature reducing device.

FIG. 7 shows a schematic control system diagram of the turbine bypass temperature reducing device, in which a pressure detector is provided in the main steam pipe (12a). The pressure detector (1e) constantly detects the steam pressure, and its detection signal is sent to the turbine bypass valve α3 via the pressure regulator αη, which opens and closes the turbine bypass valve α3. On the other hand, the desuperheater I is connected in series to the turbine binos valve α3.
Water is sent from the cooling water valve (IQ), but the opening and closing of this cooling water valve (151) is controlled by the desuperheater (14).
The temperature signal from the temperature sensor section on the outlet side of the temperature controller (
11, and after calculation there, the signal is given to the cooling water valve.

The water that has reached the appropriate temperature in this way is sent from the desuperheater (14) to the condenser (1G), and is cooled again in the condenser α1.
After that, the pump (1υ) and the waste heat boiler (6) economizer (
7).

[Problem that the invention seeks to solve]

By the way, the desuperheater I uses the heat of vaporization of the cooling water added to the steam to reduce the temperature of the steam. For this reason, since the temperature detector α ladder provided on the outlet side of the attemperator (14) is located approximately 25 m from the outlet side, a delay due to the signal may occur. for example,
When the turbine bypass valve (
Although the steam passing through the cooling water valve t15) increases rapidly, the amount of cooling water sent from the cooling water valve t15) to the desuperheater (L4) does not increase, and in the end, this is thought to be due to the signal delay. , it has been done. Signal delays are particularly noticeable during start-up, stop, and sudden load changes.

Figures 8 and 9 are graphs of fluctuations in steam flow rate and steam temperature in the case of start-up, shutdown, and rapid load changes.As can be seen from these figures, the range of fluctuation is significant. high and not well controlled.

Here, FIG. 8 shows a case where the turbine bypass valve C13 is suddenly engaged during an emergency stop of combined cycle power generation or sudden load fluctuation, and the steam flow 1 signal changes in a step manner. Due to the change in
Due to the signal delay, water is insufficiently supplied to the desuperheater (14), and the steam temperature suddenly rises. Moreover, when the step-like signal approaches the end, Ifd water flows into the desuperheater I from the time of the cooling water valve, and the steam temperature decreases more than necessary. Is this Artr? hEA”3E, hAa
, I'-Reservoir-11515-hr*IF-KJ12, NOSI:l"J77'1Ml was not at the appropriate temperature, so the condenser (In) was subjected to sudden thermal stress and thermal shock, resulting in complete damage. In addition, Figure 9 is a graph of the flow rate and temperature changes of steam flowing from the desuperheater side to the condenser (11) during startup and low load. Such fluctuations are thought to be due to the signal delay described above.

Therefore, in view of the above points, the present invention has been devised to create a turbine that is pressurized so that steam can be sent from the desuperheater to the condenser as appropriately heated water so that there is no signal delay even during startup, shutdown, and load fluctuations. It is an object of the present invention to provide a temperature control method for a bypass temperature reduction device.

[Means for solving problems]

In order to achieve the above object, the present invention includes a turbine bypass pipe K that branches a main steam pipe connecting a steam generator and a steam turbine and connects directly to a condenser, a turbine bypass valve, and a temperature reducing device. In the temperature control method of the turbine bypass temperature reduction device, water from the cooling water valve is mixed with high pressure and high temperature steam sent from the turbine bypass valve to the temperature reduction device, and the water is brought to an appropriate temperature and pressure and sent to the condenser. valve valve 7
A water temperature signal on the outlet side of the temperature reducing device is added to the temperature signal, and the calculated signal is used as an opening/closing signal for the cooling water valve.

[Effect]

The reason why the temperature of the steam flowing from the desuperheater (141) to the condenser αC fluctuates rapidly due to startup, shutdown, and load changes is thought to be due to the delay in the opening/closing signal sent to the cooling water valve (IS). Therefore, in the present invention, the turbine bypass valve (13) and the cooling water valve αS have a certain opening/closing relationship. That is, since the valve lift of the turbine bypass valve (13) is directly linked to the increase/decrease of steam, this valve 7 signal from the cooling water valve (if given as one open/close signal, the increase/decrease in the amount of steam and the increase/decrease in the amount of cooling water correspond one-to-one, and water at an appropriate temperature can be sent from the desuperheater side to the condenser α1. .

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the pressure of steam passing through the Hf steam pipe (12a) is applied to the turbine bypass 131 via a pressure detector (from IG to pressure regulator 1i7). In this state, for example, when a command to "reduce" the load is input to the turbine bypass valve Q3, the valve pressure gradually increases. At this time,
Lift detector C! υ detects the valve list, and the detection signal is corrected by the function calculator ■ and sent to the temperature controller (1'J. On the other hand, the steam temperature after passing through the attemperator α is sent to the temperature detector (1'J). 11, and the detection signal is sent to temperature controller 1.

Then, a temperature detection signal is added to the valve lift valve signal, and
This addition signal is given to the cooling water valve (ls) as an opening/closing signal.

In this way, the turbine bypass valve (13) and the cooling water valve (i
Since there is an interlocking relationship with s through the valve lift signal, the conventional signal delay is eliminated, and even if there is a start, stop, or load change, the steam flow rate is Even if the temperature fluctuates, the steam temperature can be maintained at a nearly constant value.

4 and 5 show other embodiments of the present invention, in which the steam pressure signal detected by the pressure detector tte is transmitted to the turbine bypass valve via the pressure regulator (17). While being sent to αJ, it is also sent to the function calculator ■, and from there to the temperature controller α], where the temperature signal from the temperature detector CI8 on the outlet side of the desuperheater I is added, and this added signal is given as the opening/closing signal of the cooling water valve (151). In addition, Fig. 5 shows that the pressure signal from the pressure detector (1G) is sent directly to the temperature controller α through the function calculator (1). The temperature signal on the outlet side of the desuperheater α is added to this signal, and an opening/closing signal is sent to the cooling water valve (IS) as an added signal.In both of these embodiments, the valve lift signal is In this embodiment, a steam pressure signal is used instead of the first embodiment, which is advantageous because the control system is further simplified compared to the first embodiment.

〔Effect of the invention〕

As explained above, according to the present invention, since the valve lift signal of the turbine bypass valve and the steam temperature signal on the outlet side of the attemperator are used as the opening/closing number 18 of the cooling water valve, the startup, Even if the steam passing through the turbine bypass valve suddenly increases due to shutdowns, load fluctuations, etc., cooling water corresponding to the increased amount of steam flows from the cooling water valve, and water at an appropriate temperature can flow through the condenser. As a result, it is expected that damage to the condenser will be further reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram showing one embodiment of the present invention, FIGS. 2 and 3 are characteristic diagrams obtained by the present invention, and FIGS. 4 and 5 show other embodiments of the present invention. Schematic system diagram; Figure 6 is a schematic diagram showing a conventional embodiment; Figure 7 is a partial enlarged view of a part of the turbine bypass temperature reducing device in Figure 6; Figures 8 and 9 are a diagram showing a conventional example. FIG. 3 is a characteristic diagram obtained in Example. 12a...Main steam FI pipe x2b...Turbine bypass pipe 13...Turbine bypass valve 14・Desuperheater 15・
- Cooling water valve 16... Pressure detector [7... Pressure regulator 18 Temperature detector 19 - Temperature regulator 20 - Function calculator 21... Lift detector Fig. 2 Fig. 3 National policy Fig. 4 Fig. 5

Claims (1)

[Claims] The main steam pipe that connects the steam generator and the steam turbine is branched off, and the turbine bypass pipe that connects directly to the condenser has a turbine bypass valve and a temperature reducing device, and high pressure is sent from the turbine bypass valve to the temperature reducing device.・In a temperature control method for a turbine bypass attemperature device in which water from a cooling water valve is mixed with high-temperature steam and water is made into appropriate temperature water and sent to a condenser, the outlet of the attemperation device is 1. A temperature control method for a turbine bypass temperature reduction device, characterized by adding a side water temperature signal and using the calculated signal as an opening/closing signal for a cooling water valve.