CN111927569A - Steam turbine system and method for improving flexibility of heat supply unit - Google Patents

Abstract

The invention discloses a steam turbine system and method for improving the flexibility of a heating unit. The generator of the invention has dual output shafts, two sets of overrunning clutches are arranged, and the rotor of the low pressure cylinder of the auxiliary steam turbine is disconnected online or connected to the rotor of the generator. The medium and low pressure connecting pipes are provided with a heat supply regulating valve to assist the adjustment of steam supply parameters, and an isolation valve is arranged on the steam inlet pipeline of the low pressure cylinder of the steam turbine to assist the removal of the low pressure cylinder of the steam turbine. During the heating period, the low-pressure cylinder of the first steam turbine and the low-pressure cylinder of the second steam turbine can be cut off online according to the peak-shaving demand of the power grid. The rotor of the low-pressure cylinder of the steam turbine can be completely separated from the generator without desuperheating and cooling, which eliminates the risk of blade damage caused by the low intake of steam in the low-pressure cylinder of the steam turbine. One or all of the low-pressure cylinders of the steam turbine can be selected to be removed, which enhances the flexibility of the unit's peak regulation, and can greatly improve the unit's heating capacity and improve the heating economy.

Description

A steam turbine system and method for improving the flexibility of a heating unit

【Technical field】

The invention belongs to the technical field of steam turbines, and relates to a steam turbine system and method for improving the flexibility of a heating unit.

【Background technique】

External heat supply can effectively reduce the energy consumption index of thermal power generating units, and cogeneration is also one of the important development directions of power companies. Peak shaving needs.

However, because the heating steam needs to ensure a certain pressure, and if the steam intake of the low-pressure cylinder of the steam turbine is lower than the limit value, blade damage will occur. Therefore, the inlet steam flow and load of the general heating unit will be limited by the minimum value, and it is difficult to deeply adjust the peak. If the steam turbine adopts high back pressure for heating, although the economy is good, the peak shaving capacity of the unit is poor, and the rotor needs to be removed before heating, and it cannot be switched online. Through technical means, the low-pressure cylinder of the steam turbine can be cut off or put into operation online according to peak shaving and heating demand, which can greatly enhance the peak shaving capability of the steam turbine during the heating period, improve the heating economy, and eliminate the low-pressure cylinder blades of the steam turbine during the heating period. risk of injury.

[Content of the invention]

The purpose of the present invention is to solve the problems in the prior art, and to provide a steam turbine system and method for improving the flexibility of the heating unit. Risk of water erosion.

To achieve the above object, the present invention adopts the following technical solutions to realize:

A steam turbine system for improving the flexibility of a heating unit, comprising:

The steam turbine high pressure cylinder, the steam source of the steam turbine high pressure cylinder is superheated steam, and the rotor of the steam turbine high pressure cylinder is connected with the rotor of the steam turbine middle pressure cylinder;

The middle pressure cylinder of the steam turbine, the steam source of the middle pressure cylinder of the steam turbine is reheated steam, and its rotor is connected with the rotor of the dual-shaft generator; part of the exhaust steam of the steam turbine middle pressure cylinder enters the heating pipeline for external heat supply, and the other part enters The first steam turbine low pressure cylinder and the second steam turbine low pressure cylinder;

A dual-shaft generator, the other end of the rotor of the dual-shaft generator is connected to the rotor of the low-pressure cylinder of the first steam turbine;

The first steam turbine low pressure cylinder is connected with the rotor of the second steam turbine low pressure cylinder; the exhaust steam from the first steam turbine low pressure cylinder and the second steam turbine low pressure cylinder enters the condenser.

The further improvement of the present invention is:

The dual-shaft generator and the low-pressure cylinder of the first steam turbine are connected through a first overrunning clutch.

The first steam turbine low pressure cylinder and the second steam turbine low pressure cylinder are connected through a second overrunning clutch.

The exhaust steam from the middle pressure cylinder of the steam turbine is divided into three paths, the first path enters the heating pipeline for external heat supply, the second path enters the first steam turbine low pressure cylinder through the regulating valve and the first isolation valve, and the third path passes through the regulating valve and the first isolation valve. The second isolation valve enters the second turbine low pressure cylinder.

A method of increasing the flexibility of a heating unit comprising the steps of:

When the unit is pure condensing or the external steam supply is lower than the threshold, the first isolation valve and the second isolation valve are opened, the dual-shaft generator and the first overrunning clutch are in a connected state, and the second overrunning clutch is in a connected state; the first steam turbine is in a connected state; The low-pressure cylinder and the low-pressure cylinder of the second steam turbine have steam entering and are in a normal operation state, and the external heating parameters are adjusted by the regulating valve;

When the external steam supply of the unit is large or the power grid requires deep peak regulation of the unit, the first isolation valve is opened and the second isolation valve is closed; the speed of the low-pressure cylinder of the second steam turbine decreases, the second overrunning clutch is automatically disengaged, and the low-pressure cylinder of the second steam turbine is automatically disengaged. When the output is reduced to zero, the regulating valve assists in adjusting the steam supply parameters to complete the removal process;

When the unit needs to put the second steam turbine low-pressure cylinder into operation again, the second isolation valve is opened, the speed of the second steam turbine low-pressure cylinder increases, the second overrunning clutch is automatically connected, and the output of the second steam turbine low-pressure cylinder gradually increases as required, and the regulating valve assists Adjust the steam supply parameters to complete the switching process;

When the external steam supply of the unit is higher than the threshold value, and it is necessary to cut off all the low-pressure cylinders of the steam turbine for deep peak regulation, the first isolation valve and the second isolation valve are closed, and the rotational speed of the first and second low-pressure cylinders of the steam turbine decreases; The first overrunning clutch and the second overrunning clutch are automatically disengaged, the output of the first steam turbine low pressure cylinder and the second steam turbine low pressure cylinder drop to zero, the exhaust steam of the steam turbine middle pressure cylinder is completely externally heated, and the complete removal process of the steam turbine low pressure cylinder is completed;

When the unit needs to be switched from the state of complete removal of the low-pressure cylinder of the steam turbine to the state of being put into operation, the first isolation valve is opened, and the speed of the low-pressure cylinder of the first steam turbine is increased to the same as the speed of the dual-shaft generator, and the first overrunning clutch automatically Connect; then open the second isolation valve, the speed of the second steam turbine low pressure cylinder will increase, and when the increase reaches the set speed, the second overrunning clutch will be automatically connected, and the regulating valve will assist in adjusting the steam supply parameters to complete the switching process.

Compared with the prior art, the present invention has the following beneficial effects:

The invention can cut off the low pressure cylinder of the first steam turbine and the low pressure cylinder of the second steam turbine online according to the demand for peak regulation of the power grid during the heating period. The rotor of the low-pressure cylinder of the steam turbine can be completely separated from the generator without desuperheating and cooling, which eliminates the risk of blade damage caused by the low intake of steam in the low-pressure cylinder of the steam turbine. One or all of the low-pressure cylinders of the steam turbine can be selected to be removed, which enhances the flexibility of the unit's peak regulation, and can greatly improve the unit's heating capacity and improve the heating economy.

The generator of the invention has dual output shafts, and two sets of overrunning clutches are arranged to assist the rotor of the low-pressure cylinder of the steam turbine to be disconnected online or connected to the rotor of the generator. The medium and low pressure connecting pipes are provided with a heat supply regulating valve to assist the adjustment of steam supply parameters, and an isolation valve is arranged on the steam inlet pipeline of the low pressure cylinder of the steam turbine to assist the removal of the low pressure cylinder of the steam turbine. The invention can be applied to a power generation steam turbine using the steam exhausted from the middle pressure cylinder of the steam turbine to supply heat to the outside. The risk of water erosion in the low-pressure cylinder blades of the steam turbine can increase the external heat supply of the unit, improve the heating economy, and at the same time increase the peak shaving depth of the unit. You can choose to cut off all the low-pressure cylinders of the steam turbine or only part of the low-pressure turbine according to the demand for peak shaving. The output of the low-pressure cylinder of the steam turbine can be adjusted according to the needs, and the minimum output can be reduced to zero, which enhances the flexibility of the unit operation during the heating period.

【Description of drawings】

In order to describe the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic diagram of the overall structure of the present invention.

Among them, 1- steam turbine high pressure cylinder; 2- steam turbine medium pressure cylinder; 3- double shaft generator; 4- first overrunning clutch; 5- first steam turbine low pressure cylinder; 6- second overrunning clutch; 7- second steam turbine Low pressure cylinder; 8-regulating valve; 9-first isolation valve; 10-second isolation valve; 11-condenser.

【Detailed ways】

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

Thus, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inside", etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings , or the orientation or positional relationship that the product of the invention is usually placed in use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed in a specific orientation and operation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are only used to differentiate the description and should not be construed to indicate or imply relative importance.

Furthermore, the presence of the term "horizontal" does not imply that the component is required to be absolutely horizontal, but rather may be tilted slightly. For example, "horizontal" only means that its direction is more horizontal than "vertical", it does not mean that the structure must be completely horizontal, but can be slightly inclined.

In the description of the embodiments of the present invention, it should also be noted that, unless otherwise expressly specified and limited, the terms "set", "installed", "connected" and "connected" should be understood in a broad sense. It can be a fixed connection, or a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Referring to Fig. 1, the steam turbine system for improving the flexibility of the heating unit of the present invention includes a steam turbine high pressure cylinder 1, a steam turbine medium pressure cylinder 2, a dual-shaft generator 3, a first overrunning clutch 4, a first steam turbine low pressure cylinder 5, a second steam turbine low pressure cylinder 5, and a second Overrunning clutch 6, second steam turbine low pressure cylinder 7, regulating valve 8, first isolation valve 9, second isolation valve 10; the rotor of the steam turbine middle pressure cylinder 2 is connected to the rotor of the dual-shaft generator 3, and the other end of the generator rotor It is connected with the rotor of the first steam turbine low pressure cylinder 5 by the first overrunning clutch 4 . The rotors of the first steam turbine low pressure cylinder 5 and the second steam turbine low pressure cylinder 7 are connected by a second overrunning clutch 6 . Part or all of the steam discharged from the intermediate pressure cylinder 2 of the steam turbine enters the external heating pipeline, and the part of the exhaust steam from the intermediate pressure cylinder 2 of the steam turbine that does not enter the heating pipeline enters the low pressure cylinder 5 of the first steam turbine and the low pressure cylinder 7 of the second steam turbine through the regulating valve 8 .

Principle of the present invention:

Through the opening and closing of the first isolation valve 9 and the second isolation valve 10, the first steam turbine low pressure cylinder 5 and the second steam turbine low pressure cylinder 7 can be switched on or off at any time. The online disconnection and connection of the overrunning clutch enables the first steam turbine low pressure cylinder 5 and the second steam turbine low pressure cylinder 7 to be connected and disconnected from the dual-shaft generator 3 at any time. To achieve the purpose of improving the peak regulation capacity of the heating unit, eliminating the risk of water erosion of the low-pressure cylinder blades of the steam turbine, increasing the external heat supply of the unit, and improving the heating economy.

The working process of the present invention:

When the unit is pure condensing or the external steam supply is small, the first isolation valve 9 and the second isolation valve 10 are in the open state, the dual-shaft generator 3 and the first overrunning clutch 4 are in a connected state, and the second overrunning clutch 6 is also in Connection Status. The low-pressure cylinder 5 of the first steam turbine and the low-pressure cylinder 7 of the second steam turbine have steam entering and are in a normal operation state, and the external heating parameters are adjusted by the regulating valve 8 .

When the amount of steam supplied from outside the unit is large or the power grid requires deep peak shaving of the unit, the first isolation valve 9 is in an open state, and the second isolation valve 10 is gradually closed. After that, the low-pressure cylinder 7 of the second steam turbine will gradually reduce its rotational speed due to the gradual reduction of the incoming steam to zero, the second overrunning clutch 6 will be automatically disengaged, the output of the low-pressure cylinder 7 of the second steam turbine will drop to zero, and the regulating valve 8 will assist in adjusting the steam supply parameters. Finally complete the excision process.

When the unit needs to put the second steam turbine low pressure cylinder 7 back into operation, the second isolation valve 10 is gradually opened, the second steam turbine low pressure cylinder 7 is gradually increased due to the gradual increase in steam intake, and the rotational speed is also gradually increased, the second overrunning clutch 6 is automatically connected, and the first The output of the low-pressure cylinder 7 of the second steam turbine gradually increases according to the needs, and the regulating valve 8 assists in adjusting the steam supply parameters, and finally completes the switching process.

When the unit supplies a large amount of steam to the outside, and it is necessary to cut off all the low-pressure cylinders of the turbine for deep peak regulation, the first isolation valve 9 and the second isolation valve 10 are gradually closed, and the first and second low-pressure cylinders 5 and 7 of the turbine The intake steam gradually drops to zero, and the speed also drops. At this time, the first overrunning clutch 4 and the second overrunning clutch 6 are automatically in the disengaged state, the output of the first steam turbine low pressure cylinder 5 and the second steam turbine low pressure cylinder 7 is reduced to zero, the exhaust steam of the steam turbine middle pressure cylinder 2 is completely heated to the outside, and finally Complete the complete removal process of the low pressure cylinder of the steam turbine.

When the unit needs to be switched from the state of complete removal of the low-pressure cylinder of the steam turbine to the state of being put into operation, the first isolation valve 9 is gradually opened first. At this time, the rotational speed of the low-pressure cylinder 5 of the first steam turbine is gradually increased to the same level as the rotational speed of the dual-shaft generator 3. At the same time, the first overrunning clutch 4 is automatically connected. Then gradually open the second isolation valve 10, the low-pressure cylinder 7 of the second steam turbine starts to enter steam, and the speed gradually increases. When the speed reaches a certain speed, the second overrunning clutch 6 is automatically connected, and the regulating valve 8 assists in adjusting the steam supply parameters, and finally completes the switching. fortune.

The principle of the invention is clear and the system is simple, and the low-pressure cylinder of the steam turbine can be put into operation and stopped online without stopping the operation. It is suitable for all heating generator sets with low-pressure cylinders of steam turbines. It is an innovative technology to enhance the peak-shaving capacity of heating units, eliminate the risk of water erosion in the low-pressure cylinders of steam turbines, and increase the heat supply to improve the heating economy of the units.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. A steam turbine system for improving flexibility of a heat supply unit is characterized by comprising:

the steam turbine high-pressure cylinder (1), the steam source of the steam turbine high-pressure cylinder (1) is superheated steam, and the rotor of the steam turbine high-pressure cylinder is connected with the rotor of the steam turbine intermediate-pressure cylinder (2);

the steam turbine intermediate pressure cylinder (2), the steam source of the steam turbine intermediate pressure cylinder (2) is reheat steam, and the rotor of the steam turbine intermediate pressure cylinder is connected with the rotor of the double-output-shaft generator (3); one part of the steam discharged by the steam turbine intermediate pressure cylinder (2) enters a heat supply pipeline to supply heat to the outside, and the other part of the steam enters a first steam turbine low pressure cylinder (5) and a second steam turbine low pressure cylinder (7);

the other end of the rotor of the double-output-shaft generator (3) is connected with the rotor of the first turbine low-pressure cylinder (5);

the first turbine low-pressure cylinder (5), the first turbine low-pressure cylinder (5) is connected with the rotor of the second turbine low-pressure cylinder (7); the exhaust steam of the first turbine low-pressure cylinder (7) and the second turbine low-pressure cylinder (7) enters a condenser (11).

2. Steam turbine system for increasing the flexibility of a heating unit according to claim 1, characterized in that the double output shaft generator (3) is connected with the first low pressure turbine cylinder (5) through a first overrunning clutch (4).

3. Steam turbine system for increasing flexibility of a heating unit according to claim 1 or 2, characterized in that the first and second low-pressure turbine cylinders (5, 7) are connected by a second overrunning clutch (6).

4. The steam turbine system for improving the flexibility of the heat supply unit according to claim 1 or 2, wherein the steam exhaust of the intermediate pressure cylinder (2) of the steam turbine is divided into three paths, the first path enters the heat supply pipeline to supply heat to the outside, the second path enters the first low pressure cylinder (5) of the steam turbine through the regulating valve (8) and the first isolating valve (9), and the third path enters the second low pressure cylinder (7) of the steam turbine through the regulating valve (8) and the second isolating valve (10).

5. A method for increasing the flexibility of a heating unit using the system of claim 4, comprising the steps of:

when the engine set is pure condensed or the external steam supply amount is lower than a threshold value, a first isolation valve (9) and a second isolation valve (10) are opened, the double-output-shaft generator (3) and the first overrunning clutch (4) are in a connected state, and the second overrunning clutch (6) is in a connected state; steam enters the first steam turbine low pressure cylinder (5) and the second steam turbine low pressure cylinder (7) and is in a normal running state, and external heat supply parameters are adjusted by an adjusting valve (8);

when the steam supply quantity outside the unit is large or the power grid needs unit deep peak shaving, the first isolation valve (9) is opened, and the second isolation valve (10) is closed; the rotating speed of the second steam turbine low pressure cylinder (7) is reduced, the second overrunning clutch (6) is automatically disengaged, the output of the second steam turbine low pressure cylinder (7) is reduced to zero, and the regulating valve (8) is used for assisting in regulating steam supply parameters to complete the cutting process;

when the unit needs to put the second steam turbine low-pressure cylinder (7) into operation again, a second isolation valve (10) is opened, the rotating speed of the second steam turbine low-pressure cylinder (7) rises, the second overrunning clutch (6) is automatically connected, the output of the second steam turbine low-pressure cylinder (7) gradually rises according to the requirement, and the regulating valve (8) is used for assisting in regulating steam supply parameters to complete the switching operation process;

when the external steam supply of the unit is higher than a threshold value and all the low-pressure cylinders of the turbine are required to be cut off for deep peak regulation, closing the first isolation valve (9) and the second isolation valve (10), and reducing the rotating speed of the first low-pressure cylinder (5) and the second low-pressure cylinder (7) of the turbine; the first overrunning clutch (4) and the second overrunning clutch (6) are automatically in a disengaged state, the output of the first steam turbine low pressure cylinder (5) and the second steam turbine low pressure cylinder (7) is reduced to zero, and the exhaust steam of the steam turbine intermediate pressure cylinder (2) completely supplies heat to the outside to complete the complete cutting process of the steam turbine low pressure cylinder;

when the unit needs to be switched from a complete cutting-off state of a low-pressure cylinder of the steam turbine to a commissioning state, a first isolation valve (9) is opened, the rotating speed of the low-pressure cylinder (5) of the first steam turbine is increased, and when the rotating speed of the low-pressure cylinder of the first steam turbine is increased to be the same as that of the double-output-shaft generator (3), a first overrunning clutch (4) is automatically connected; and then the second isolating valve (10) is opened, the rotating speed of the second steam turbine low-pressure cylinder (7) is increased, the second overrunning clutch (6) is automatically connected when the rotating speed is increased to the set rotating speed, and the regulating valve (8) is used for assisting in regulating steam supply parameters to complete the switching operation process.

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