CN114776394A - A dual-cycle steam turbine power generation system - Google Patents

Abstract

The invention relates to the technical field of thermal power generation systems, in particular to a dual-cycle steam turbine power generation system, comprising: a first cycle pipeline, including a cyclically connected turbine, a condenser body, a compressor and a heater body; a second cycle The pipeline, including the cyclically connected steam turbine unit, condenser, multi-stage low-pressure heater, deaerator, multi-stage high-pressure heater and evaporator; both low-pressure heater and high-pressure heater are arranged in parallel with the liquid side of the condenser body There is a steam pipeline connected between the low-pressure heater, the high-pressure heater and the deaerator and the steam turbine unit, and the hot side of the heater body is installed on the steam pipeline in series. Through the coupling and cooperation of the first circulation pipeline and the second circulation pipeline, the heat in the steam turbine unit is utilized in a cascade, so as to reduce the superheat degree of the regenerative exhaust gas of the steam turbine unit and reduce the heat exchange.

The loss can increase the power generation system's working capacity and on-grid electricity, and reduce the energy consumption of the power generation system.

Description

A dual-cycle steam turbine power generation system

technical field

The invention relates to the technical field of thermal power generation systems, in particular to a dual-cycle steam turbine power generation system.

Background technique

Coal-fired generating units not only provide large-scale power security, but also consume a large amount of coal resources and cause environmental pollution. Therefore, the efficient and clean operation of coal-fired units can not only save precious coal resources, improve energy conversion and utilization efficiency, reduce energy costs of thermal power companies, but also improve environmental quality and reduce pollution emissions, which has significant social benefits.

As the core part of the steam turbine, the performance of the thermal system has a direct impact on the energy consumption, efficiency, and emissions of the steam turbine. The steam turbine unit in the prior art has a higher degree of superheat of the regenerative extraction steam, a large heat exchange temperature difference of the evaporator, and a higher heat loss during the heat exchange process, resulting in an increase in the overall energy consumption of the steam turbine unit.

SUMMARY OF THE INVENTION

Therefore, the technical problem to be solved by the present invention is to overcome the defect of high heat loss in the heat exchange process in the existing steam turbine unit, which leads to increased energy consumption of the steam turbine unit, thereby providing a dual-cycle steam turbine power generation system.

In order to solve the above technical problems, the present invention provides a dual-cycle steam turbine power generation system, comprising:

The first circulation pipeline, including the circulating turbine, the condenser body, the compressor and the heater body;

The second circulation pipeline, including the cyclically connected steam turbine unit, condenser, multi-stage low-pressure heater, deaerator, multi-stage high-pressure heater and evaporator;

Both the low pressure heater and the high pressure heater are arranged in parallel with the liquid side of the condenser body;

A steam pipeline is connected between the low-pressure heater, the high-pressure heater, the deaerator and the steam turbine unit, and the hot side of the heater body is installed on the steam pipeline in series.

Optionally, the condenser bodies are sequentially installed in series with multiple stages, the liquid-side inlet end of the final-stage condenser body is communicated with the condenser, and the liquid-side outlet end of the final-stage condenser body is communicated with the outlet end of the first-stage low-pressure heater. .

Optionally, the liquid-side inlet end of the first-stage condenser body communicates with the outlet end of a certain high-pressure heater, and the liquid-side outlet end of the first-stage condenser body communicates with the inlet end of the last-stage high-pressure heater.

Optionally, the heater bodies are installed in series with multiple stages, and the hot side of a group of heater bodies is communicated with at least one steam pipeline.

Optionally, a first drain pipeline is communicated between the high pressure heater of the latter stage and the high pressure heater of the previous stage, and a second drain pipeline is communicated between the high pressure heater of the first stage and the deaerator.

Optionally, a third drainage pipeline is communicated between the low-pressure heater of the latter stage and the low-pressure heater of the previous stage, and a fourth drainage pipeline is communicated between the low-pressure heater of the first stage and the condenser.

Optionally, a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder are installed in the steam turbine unit, and a steam pipeline is connected between the medium-pressure cylinder and the last-stage low-pressure heater, the deaerator and the first-stage high-pressure heater, which is connected to the medium-pressure heater. A heater body is installed in series on the steam pipes connected to the cylinders.

Optionally, a plurality of steam pipelines are communicated with the high-pressure cylinder, and the steam pipelines communicated with the high-pressure cylinder and the multi-stage high-pressure heaters other than the first stage are connected in one-to-one correspondence.

Optionally, a plurality of steam pipelines are communicated with the low-pressure cylinder, and the steam pipelines communicated with the low-pressure cylinder and the multi-stage low-pressure heaters other than the last stage are connected in one-to-one correspondence.

Optionally, a heater body is installed on the steam pipeline communicating with the low-pressure cylinder.

The technical scheme of the present invention has the following advantages:

1. The dual-cycle steam turbine power generation system provided by the present invention includes: a first circulation pipeline, including a cyclically connected turbine, a condenser body, a compressor and a heater body; a second circulation pipeline, including a cyclically connected Steam turbine unit, condenser, multi-stage low-pressure heater, deaerator, multi-stage high-pressure heater and evaporator; both low-pressure heater and high-pressure heater are arranged in parallel with the liquid side of the condenser body; low-pressure heater, high-pressure heater A steam pipeline is connected between the deaerator and the deaerator and the steam turbine unit, and the hot side of the heater body is installed on the steam pipeline in series.

损失，同时第一循环回路中的透平机和第二循环回路中的汽轮机组均能够驱动发电机对外输出电能，能够增大发电系统做功能力及上网电量，降低发电系统的能耗。The first circulation pipeline is used as the Brayton cycle, and the second circulation pipeline is used as the power generation pipeline. When the dual-cycle steam turbine power generation system performs power generation work, the steam drives the steam turbine unit to rotate to generate electricity. The steam discharged from the steam turbine is condensed into a liquid state through the condenser and then input to the multi-stage low-pressure heater. After heat exchange and deoxygenation in the oxygenator, it is input to the multi-stage high-pressure heater, and after being heated up by stage-by-stage high-pressure heating, it is converted into steam through the evaporator and re-input to the steam turbine unit. By installing the liquid side of the condenser body on the low-pressure heater and the high-pressure heater in parallel, the heat in the condenser body is transferred to the low-pressure heater and the high-pressure heater. The liquid is heated up, and the gas on the gas side in the condenser is cooled at the same time; at the same time, a steam pipeline is set between the low-pressure heater, the high-pressure heater, the deaerator and the steam turbine unit, and the heater body in the first circulation pipeline is installed. It is installed in series on the steam pipeline, absorbs heat from the steam pipeline, and heats the medium in the first circulation pipeline. Through the coupling and cooperation of the first circulation pipeline and the second circulation pipeline, the heat in the steam turbine unit is utilized in a cascade through the low-pressure heater, the high-pressure heater and the heater body, so as to reduce the superheat degree of the regenerative exhaust gas of the steam turbine unit and reduce the small heat exchange

At the same time, the turbine in the first circulation loop and the steam turbine unit in the second circulation loop can both drive the generator to output electric energy to the outside, which can increase the working capacity of the power generation system and the power on the grid, and reduce the energy consumption of the power generation system.

2. In the dual-cycle steam turbine power generation system provided by the present invention, the condenser body is sequentially installed in series with multiple stages, the liquid-side inlet end of the final-stage condenser body is communicated with the condenser, and the liquid-side outlet end of the final-stage condenser body is connected to the condenser. The outlet end of the first stage low pressure heater is communicated. By arranging multi-stage condenser bodies, the multi-stage condenser bodies are respectively connected with different high-pressure heaters or low-pressure heaters, so that the inlet and outlet temperatures of different condenser bodies are consistent with the corresponding high-pressure heater or low-pressure heater inlet and outlet temperatures. Matching, improve the heat exchange efficiency between the condenser body and the low-pressure heater or high-pressure heater.

3. In the dual-cycle steam turbine power generation system provided by the present invention, the heater bodies are installed in series with multiple stages, and the hot side of a group of heater bodies is connected in series with at least one steam pipeline. The multi-stage series-connected heater body and the steam pipeline are used in series to absorb the heat in the steam pipeline, gradually increase the temperature of the medium in the first circulation pipeline, and at the same time transport the steam to the high-pressure heater through the steam pipeline. Or the steam temperature of the low-pressure heater matches the internal temperature of the corresponding high-pressure heater or low-pressure heater, so as to improve the heat exchange efficiency and make full use of the excess heat in the steam turbine unit.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

FIG. 1 is a dual-cycle steam turbine power generation system provided in an embodiment of the present invention.

Description of reference numerals: 1, high pressure cylinder; 2, medium pressure cylinder; 3, low pressure cylinder; 4, generator; 5, condenser; 6, condensate pump; 7, low pressure heater; 8, deaerator; 9 10, high pressure heater; 11, evaporator; 12, turbine; 13, condenser body; 14, compressor; 15, heater body.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. 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.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Example

As shown in FIG. 1 , a dual-cycle steam turbine power generation system provided in this embodiment includes: a first circulation pipeline used as a Brayton cycle and a second cycle pipeline used as a power generation cycle.

The first circulation pipeline includes a circulating turbine 12 , a condenser body 13 , a compressor 14 and a heater body 15 . The second circulation pipeline includes a cyclically connected steam turbine unit, a condenser 5, a condensate pump 6, a low-pressure heater 7 connected in series with four stages, a deaerator 8, a feed water pump 9, a high-pressure heater 10 connected in series with three stages, and A boiler as the evaporator 11 . Both the low-pressure heater 7 and the high-pressure heater 10 are arranged in parallel with the liquid side of the condenser body 13 . A steam pipeline is connected between the low-pressure heater 7, the high-pressure heater 10, the deaerator 8 and the steam turbine unit, and the hot side of the heater body 15 is installed on the steam pipeline in series. A first drainage pipeline is communicated between the high pressure heater 10 of the latter stage and the high pressure heater 10 of the previous stage, and a second drainage pipeline is communicated between the high pressure heater 10 of the first stage and the deaerator 8 . A third drainage pipeline is communicated between the low pressure heater 7 of the latter stage and the low pressure heater 7 of the previous stage, and a fourth drainage pipeline is communicated between the low pressure heater 7 of the first stage and the condenser 5 .

The condenser body 13 is sequentially installed in series with multiple stages, the liquid side inlet end of the last stage condenser body 13 is communicated with the condenser 5 , the liquid side outlet end of the last stage condenser body 13 is connected with the outlet end of the first stage low pressure heater 7 Connected. The liquid-side inlet end of the first-stage condenser body 13 is communicated with the outlet end of a certain high-pressure heater 10 , and the liquid-side outlet end of the first-stage condenser body 13 is communicated with the inlet end of the last-stage high-pressure heater 10 . Specifically, the condenser body 13 is provided with four stages in series, and the condensate water flowing out from the outlet end of the condensate pump 6 is divided into two strands, one strand directly enters the low-pressure heater 7 of the first stage, and the other strand enters the low-pressure heater 7 of the fourth stage. The liquid side of the condenser body 13 is heated up and merged into the outlet end of the first-stage low-pressure heater 7 . The condensed water output from the second-stage low-pressure heater 7 is heated through the third condenser body 13 and then merged into the outlet end of the third-stage low-pressure heater 7 . The condensed water output from the outlet of the fourth-stage low-pressure heater 7 passes through the liquid side of the second-stage condenser body 13 to be heated and directly enters the deaerator 8 . The inlet end of the first-stage condenser body 13 is communicated with the outlet end of the first-stage high-pressure heater 10, and the outlet end of the first-stage condenser body 13 is merged into the outlet end of the second-stage high-pressure heater 10. The feed water enters the high pressure heater 10 in the third stage.

A high-pressure cylinder 1, a medium-pressure cylinder 2 and a low-pressure cylinder 3 are installed in the steam turbine unit. A steam pipeline is connected between the medium-pressure cylinder 2 and the last-stage low-pressure heater 7, the deaerator 8 and the first-stage high-pressure heater 10. A heater body 15 is installed in series on the steam pipelines communicating with the medium pressure cylinder 2 . The high-pressure cylinder 1 is connected with a plurality of steam pipelines, and the steam pipelines in communication with the high-pressure cylinder 1 are in one-to-one correspondence with the multi-stage high-pressure heaters 10 other than the first stage. The low-pressure cylinder 3 is connected with a plurality of steam pipelines, and the steam pipelines communicated with the low-pressure cylinder 3 and the multi-stage low-pressure heaters 7 other than the last stage are connected in one-to-one correspondence. A heater body 15 is installed in series on one of the steam pipelines communicating with the low-pressure cylinder 3 . The heater bodies 15 are installed in multiple stages in series, and the hot side of a group of heater bodies 15 is connected in series with at least one steam pipeline. Specifically, the heater body 15 is provided with four stages in series, and a steam pipeline is correspondingly connected in series on the hot side of the heater body 15 of each stage. The high-pressure cylinder 1 is connected with two steam pipelines, which are respectively communicated with the third-stage high-pressure heater 10 and the second-stage high-pressure heater 10 . The medium pressure cylinder 2 is connected with three steam pipelines, which are respectively connected with the high pressure heater 10 of the first stage, the deaerator 8 and the low pressure heater 7 of the fourth stage. A heater body 15 is installed in series on the three steam pipelines connected to the medium pressure cylinder 2 . The low-pressure cylinder 3 is connected with three steam pipelines, which are respectively communicated with the low-pressure heater 7 of the first stage, the low-pressure heater 7 of the second stage and the low-pressure heater 7 of the third stage. A heater body 15 is installed on the steam pipeline between the low pressure cylinder 3 and the low pressure cylinder 3 .

In this embodiment, the medium in the first circulation line is carbon dioxide, and the medium in the second circulation line is liquid water and steam. In the second circulation pipeline, the steam heated by the evaporator 11 enters the high pressure cylinder 1 and then returns to the evaporator 11 for a second temperature rise, and then enters the medium pressure cylinder 2 and the low pressure cylinder 3 to drive the steam turbine unit to operate and drive power generation. The machine 4 performs power generation work. The high pressure cylinder 1 , the medium pressure cylinder 2 , the low pressure cylinder 3 and the generator 4 are coaxially connected. The steam output from the low-pressure cylinder 3 is condensed into condensed water through the condenser 5, and is input to the low-pressure heater 7 connected in four stages through the condensate pump 6, and then enters the second-stage condenser body 13 for heat exchange, and then enters the deaerator 8. After deoxidizing operation, it is input to the three-stage series high pressure heater 10 through the feed water pump 9, and finally returns to the evaporator 11 to complete the cycle. Among them, steam pipes are arranged between the high-pressure cylinder 1 and the third-stage high-pressure heater 10 and the second-stage high-pressure heater 10 to utilize the heat of the steam in the high-pressure cylinder 1 in the feed water; A steam pipeline is communicated between the high pressure heater 10 of the first stage, the deaerator 8 and the low pressure heater 7 of the fourth stage to utilize the heat in the steam in the medium pressure cylinder 2 in the feed water and condensed water; A steam pipeline is connected between the low pressure cylinder 3 and the first stage low pressure heater 7, the second stage low pressure heater 7 and the third stage low pressure heater 7 to utilize the heat of the steam in the low pressure cylinder 3 in the condensed water. In the first circulation pipeline, the high-temperature carbon dioxide output from the turbine 12 enters the condenser body 13 connected in four stages in series for cooling, and then enters the compressor 14 for compression, and the compressed high-pressure carbon dioxide is heated in four stages in series. The condenser body 15 is further heated and then transported to the turbine 12 to drive the turbine 12 to rotate, and the carbon dioxide output from the turbine 12 is re-input into the condenser body 13 to complete the cycle.

损失，第一循环管路中的透平上也可同轴安装发电机4来对外输出电能，回收布雷顿透平排汽热量，增加汽轮机做功能力，能够增大系统做功能力及上网电量，降低汽轮机组的能耗。The hot sides of the four heater bodies 15 in the first circulation line are respectively installed on different steam lines, and heat is taken from the steam lines to heat up the carbon dioxide. The four-stage condenser body 13 in the first circulation pipeline, the first-stage condenser body 13 is connected in parallel with both ends of the first-stage low-pressure heater 7, and the second-stage condenser body 13 is connected in parallel with the third-stage low-pressure heater 7, the third-stage condenser body 13 is connected in series between the fourth-stage low-pressure heater 7 and the deaerator 8, and the fourth-stage condenser body 13 is installed in parallel with both ends of the second-stage high-pressure heater 10. The condenser body 13 condenses and cools the carbon dioxide in the first circulation pipe by heating and raising the temperature of the water in the second circulation pipe. The multi-stage coupling heat exchange is carried out through the first circulation pipeline and the second circulation pipeline, and the superheat and subcooling degree of the steam turbine regenerative system are reasonably utilized through the carbon dioxide Brayton cycle, which can greatly reduce the superheat degree of the regenerative extraction steam and reduce the low pressure heating. The heat exchange temperature difference between the heater 7 and the high pressure heater 10 reduces the heat exchange

The generator 4 can also be coaxially installed on the turbine in the first circulation pipeline to output electric energy externally, recover the exhaust heat of the Brayton turbine, and increase the working capacity of the steam turbine, which can increase the working capacity of the system and the power on the grid. , reduce the energy consumption of the steam turbine unit.

The steam pipeline is communicated with the outlet end of the high pressure heater 10 or the low pressure heater 7 , and the steam temperature in the steam pipeline matches the fluid temperature at the outlet end of the corresponding high pressure heater 10 or the low pressure heater 7 . After optimization, when the inlet steam pressure of Brayton cycle turbine 12 is 29MPa, the exhaust steam pressure is 8.13MPa, and the circulating carbon dioxide amount is 68t/h, the overall system energy consumption is the lowest, the corresponding Brayton turbine power is 9.16MW, and the system heat consumption is estimated Reduced by 52kJ/kWh, coal consumption for power supply is reduced by 0.61g/kWh, and the consumption reduction effect is remarkable. The turbine 12 in the Brayton cycle is used for power generation, which can increase the power of the unit on the grid. The electricity price is calculated at 0.4 yuan/kWh and the annual utilization hour is calculated as 4000h. Compressor 14 consumes electricity).

As an alternative embodiment, both the heater body and the condenser body may be multi-channel heat exchangers.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (10)

1. A dual cycle steam turbine power generation system, comprising:

the first circulation pipeline comprises a turbine (12), a condenser body (13), a compressor (14) and a heater body (15) which are connected in a circulation mode;

the second circulating pipeline comprises a turbine set, a condenser (5), a multi-stage low-pressure heater (7), a deaerator (8), a multi-stage high-pressure heater (10) and an evaporator (11) which are connected in a circulating manner;

the low-pressure heater (7) and the high-pressure heater (10) are both arranged in parallel with the liquid side of the condenser body (13);

the low-pressure heater (7), the high-pressure heater (10) and the deaerator (8) with all communicate there is the steam pipe way between the turboset, the hot side series connection of heater body (15) is installed on the steam pipe way.

2. The dual cycle steam turbine power generation system of claim 1, wherein the condenser bodies (13) are sequentially installed in series in a plurality of stages, a liquid side inlet end of the condenser body (13) at the final stage is communicated with the condenser (5), and a liquid side outlet end of the condenser body (13) at the final stage is communicated with an outlet end of the low pressure heater (7) at the first stage.

3. The dual cycle steam turbine power generation system of claim 2, wherein the liquid side inlet of the condenser body (13) of the first stage communicates with an outlet of one of the high pressure heaters (10), and the liquid side outlet of the condenser body (13) of the first stage communicates with an inlet of the high pressure heater (10) of the last stage.

4. A dual cycle steam turbine power generation system according to any one of claims 1 to 3, wherein the heater bodies (15) are mounted in series in a plurality of stages, the hot side of a group of the heater bodies (15) being in communication with at least one of the steam lines.

5. The dual cycle steam turbine power generation system of any one of claims 1 to 3, wherein a first drain line is communicated between the next stage high pressure heater (10) and the previous stage high pressure heater (10), and a second drain line is communicated between the first stage high pressure heater (10) and the deaerator (8).

6. The dual cycle steam turbine power generation system according to any one of claims 1 to 3, wherein a third drain line is communicated between the next stage low pressure heater (7) and the previous stage low pressure heater (7), and a fourth drain line is communicated between the first stage low pressure heater (7) and the condenser (5).

7. The dual cycle steam turbine power generation system of any one of claims 1 to 3, wherein a high pressure cylinder (1), an intermediate pressure cylinder (2) and a low pressure cylinder (3) are installed in the steam turbine unit, the steam pipeline is communicated between the intermediate pressure cylinder (2) and the last low pressure heater (7), the deaerator (8) and the first high pressure heater (10), and the heater body (15) is installed in series on the steam pipeline communicated with the intermediate pressure cylinder (2).

8. The dual cycle steam turbine power generation system of claim 7, wherein the high pressure cylinder (1) is connected to a plurality of steam lines, and the steam lines connected to the high pressure cylinder (1) are connected to the high pressure heaters (10) of different stages other than the first stage in a one-to-one correspondence manner.

9. The dual cycle steam turbine power generation system according to claim 7, wherein a plurality of the steam lines communicate with the low pressure cylinder (3), and the steam lines communicating with the low pressure cylinder (3) communicate with the plurality of stages of the low pressure heaters (7) other than the final stage in a one-to-one correspondence.

10. The dual cycle steam turbine power generation system according to claim 9, wherein the heater body (15) is installed on the steam pipe communicating with the low pressure cylinder (3).

Images