CN117537328A - Thermal power generation heat supply unit - Google Patents

Abstract

The invention discloses a thermal power generation heat supply unit, which relates to the technical field of thermal power generation, and comprises a primary reheating boiler and a steam generation system for supplying heat to the outside, and further comprises a steam recovery system, wherein the primary reheating boiler is used for providing first steam required by heat exchange for the steam generation system, and the steam recovery system is used for recovering intermediate steam in the heat exchange process, and reducing the pressure of the intermediate steam and returning the intermediate steam to a low-pressure steam pipeline of the primary reheating boiler; the ratio of the steam pressure of the intermediate steam to the steam pressure of the first steam is greater than or equal to a preset value, and the temperature of the intermediate steam is lower than the temperature of the first steam. The thermal power generation heat supply unit is not limited by the through flow of the steam turbine cylinder when supplying heat to the outside, can not influence the generated energy, and can fully utilize high-quality steam.

Description

Thermal power generation heat supply unit

Technical Field

The invention relates to the technical field of thermal power generation, in particular to a thermal power generation heat supply unit.

Background

Conventional thermal power generation generally adopts a single reheat boiler and a matched turbo generator set to generate electricity, when heat is supplied to the outside, corresponding steam is generally extracted from a cylinder body of a steam turbine to supply the heat to the outside according to heat supply requirements, but the mode of extracting the steam is limited by the through flow of the cylinder of the steam turbine, namely when the steam extraction quantity is overlarge, the cylinder is easy to cause the condition of blowing, the turbine overspeed and other accidents are caused, meanwhile, the generated energy and the extracted steam quantity can be mutually influenced, and the balance of the generated energy and the extracted steam is difficult under the condition of tension of the power supply requirements and the heat supply requirements.

Disclosure of Invention

The present invention aims to solve one of the technical problems in the related art to a certain extent. Therefore, the thermal power generation heat supply unit is not limited by the through flow of the steam turbine and does not influence the generated energy when supplying heat to the outside, and high-quality steam can be fully utilized.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the thermal power generation heat supply unit comprises a primary reheating boiler and a steam generation system for supplying heat to the outside, and further comprises a steam recovery system, wherein the primary reheating boiler is used for providing first steam required by heat exchange for the steam generation system, and the steam recovery system is used for recovering intermediate steam in the heat exchange process and reducing the pressure of the intermediate steam and returning the intermediate steam to a low-pressure steam pipeline of the primary reheating boiler; the ratio of the steam pressure of the intermediate steam to the steam pressure of the first steam is greater than or equal to a preset value (while less than 100%), and the temperature of the intermediate steam is lower than the temperature of the first steam.

Optionally, the steam recovery system includes a pressure matcher, a working fluid inlet on the pressure matcher receives the intermediate steam, and a mixed fluid outlet on the pressure matcher is communicated with a low-pressure steam pipeline of the primary reheating boiler.

Optionally, an injection fluid inlet on the pressure matcher is used for receiving second cooling steam, and the steam generation system can receive the second steam and output the second cooling steam after heat exchange; the second cooling steam has a lower steam pressure than the intermediate steam.

Optionally, the system also comprises a steam turbine generator set; one of the primary reheat boiler and the steam turbine generator set's cylinder is capable of providing the second steam for heat exchange to the steam generation system; the steam recovery system is capable of recovering the intermediate steam and the second cooling steam simultaneously.

Optionally, a main steam pipeline is communicated between the primary reheating boiler and the steam turbine generator set; the main steam line is connected with the steam generation system to provide the first steam to the steam generation system.

Optionally, a high-temperature reheat steam pipeline is communicated between the primary reheat boiler and the steam turbine generator set, and the high-temperature reheat steam pipeline is connected with the steam generation system so as to provide the second steam for the steam generation system.

Optionally, the steam generating system includes a main superheater, a heat medium inlet of the main superheater is communicated with the main steam pipeline, so that after heat exchange with the first steam, a heat medium outlet of the main superheater can output the intermediate steam to a working fluid inlet on the pressure matcher, and a heat steam outlet of the main superheater can output steam for supplying heat to the outside.

Optionally, the steam generation system includes a secondary superheater; the heat medium inlet of the auxiliary superheater is communicated with the high-temperature reheating steam pipeline, so that after heat exchange with the second steam, the heat medium outlet of the auxiliary superheater can output the second cooling steam to the injection fluid inlet on the pressure matcher, and the steam outlet of the auxiliary superheater can output steam for supplying heat to the outside.

Optionally, the steam generation system further comprises an evaporator and a steam drum; the steam drum is communicated with the evaporator; the heat medium inlet of the evaporator is communicated with the heat medium outlet of the main superheater so that after heat exchange with the intermediate steam, the evaporator can generate initial steam for supplying heat to the outside and supply the initial steam to the steam inlet of the main superheater or the steam inlet of the auxiliary superheater respectively through the steam outlet of the steam drum.

Optionally, the steam generation system further comprises a heater; the heat medium inlet of the heater is communicated with the heat medium outlet of the evaporator; the water outlet of the heater is communicated with the water inlet of the steam drum, and the heater can provide hot water for the steam drum.

Optionally, an external condensate tank is arranged on the evaporator, and the condensate tank is communicated with the evaporator; the steam turbine generator unit is provided with a water supply pipeline, the condensate tank is connected with the water supply pipeline, and a condensate booster pump is arranged on a connecting pipeline between the condensate tank and the water supply pipeline.

Optionally, the steam generating system further comprises a surge tank, and the surge tank is arranged between the condensate booster pump and the condensate tank; the condensate tank is provided with a fourth pressure regulating valve, and the fourth pressure regulating valve can control the pressure of the pressure stabilizing tank.

Optionally, the steam generation system further comprises a first pressure regulating valve arranged between the main steam pipeline and the main superheater, and the first pressure regulating valve can regulate the opening degree according to the pressure in the steam drum; when the pressure in the steam drum is smaller than a preset value, the opening of the first pressure regulating valve is increased; and when the pressure in the steam drum is larger than or equal to a preset value, the first pressure regulating valve is kept at a preset opening degree.

Optionally, the steam generating system further includes a first temperature adjusting valve, where the first temperature adjusting valve is disposed on a pipeline of the steam inlet of the auxiliary superheater, and the first temperature adjusting valve can adjust the opening according to a comparison result of the steam temperature of the steam outlet of the main superheater and the steam temperature of the steam outlet of the auxiliary superheater, so that a steam temperature difference between the steam outlets of the main superheater and the auxiliary superheater is maintained within a preset error range.

Optionally, the steam outlet of the main superheater is connected in parallel with the steam outlet of the auxiliary superheater to supply heat to the outside.

Optionally, the steam generation system further comprises a second pressure regulating valve and a desuperheater; the second pressure regulating valve and the desuperheater are arranged on a pipeline for supplying heat after the steam outlet of the main superheater is connected in parallel with the steam outlet of the auxiliary superheater.

Optionally, the steam generating system includes a three-way valve disposed on a pipeline between the heat medium inlet of the auxiliary superheater, the high-temperature reheat steam pipeline and the cylinder of the turbo generator set, and the three-way valve can enable the heat medium inlet of the auxiliary superheater to be selectively communicated with one of the high-temperature reheat steam pipeline and the cylinder of the turbo generator set.

These features and advantages of the present invention will be disclosed in more detail in the following detailed description and the accompanying drawings. The best mode or means of the present invention will be described in detail with reference to the accompanying drawings, but is not limited to the technical scheme of the present invention. In addition, these features, elements, and components are shown in plural in each of the following and drawings, and are labeled with different symbols or numerals for convenience of description, but each denote a component of the same or similar construction or function.

Drawings

The invention is further described below with reference to the accompanying drawings:

fig. 1 is a schematic diagram of a thermal power generation and heating unit according to this embodiment.

Fig. 2 is an enlarged view of fig. 1 at the primary superheater, the secondary superheater and the pressure matcher.

100 parts of a primary reheating boiler; 110. a main steam pipe; 120. a high temperature reheat steam line; 130. a low pressure steam line; 140. a high pressure water supply line; 200. a steam turbine generator set; 310. a main superheater; 320. a secondary superheater; 410. an evaporator; 420. a steam drum; 430. a condensate tank; 440. a surge tank; 500. a heater; 610. a first pressure regulating valve; 620. a second pressure regulating valve; 630. a third pressure regulating valve; 640. a fourth pressure regulating valve; 650. a condensate booster pump; 660. a first temperature regulating valve; 670. desuperheater; 680. a second temperature regulating valve; 700. and a pressure matcher.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The examples in the embodiments are intended to illustrate the present invention and are not to be construed as limiting the present invention.

Reference in the specification to "one embodiment" or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment itself can be included in at least one embodiment of the present patent disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

Examples:

as shown in fig. 1 and 2, there is shown a thermal power generation and heating unit including a primary reheat boiler 100, a steam generation system for externally supplying heat, and a steam recovery system. The primary reheating boiler 100 is configured to provide first steam required for heat exchange to the steam generating system, and the steam recovery system is configured to recover intermediate steam (i.e., cooling steam after heat exchange of the first steam) in the heat exchange process, and to depressurize the intermediate steam and return the intermediate steam to the low-pressure steam pipe 130 of the primary reheating boiler 100.

The first steam and the intermediate steam are both high quality steam, i.e. the steam pressure of both is relatively high, e.g. typically above 11 Mpa. The first steam has a relatively high temperature, for example, generally above 500 ℃, and after the first steam exchanges heat with the steam generating system for a plurality of times, the temperature of the first steam gradually decreases along with the heat exchange times, but the steam pressure loss during each heat exchange process is almost negligible. The ratio of the steam pressure of the intermediate steam to the steam pressure of the first steam is greater than or equal to a preset value, and the preset value is preferably 95%; while the upper limit of the ratio is less than 100%. The steam pressure of the first steam and the intermediate steam is higher than that of the low-pressure steam pipeline of the primary reheating boiler.

The intermediate steam is the product of the first steam and the steam generating system after the first heat exchange, and the steam temperature of the intermediate steam, the second cooling steam and the steam temperature of the cold reheat steam of the turbine (i.e. the steam in the low pressure steam pipeline 130) are equivalent. Since the intermediate steam is subjected to one heat exchange, the temperature of the intermediate steam is lower than that of the first steam by about 200 ℃.

According to the scheme, the steam generation system directly extracts first steam from the sequential reheating boiler as a heat medium to perform heat exchange, then outputs steam for external heat supply, changes the original mode of directly extracting steam from the side of the steam turbine generator set 200 in the thermal power generation heat supply unit, is not limited by the through-flow restriction of the cylinder body of the steam turbine, can not influence the power generation of the steam turbine when external heat supply is performed, and the loss of intermediate steam pressure after primary heat exchange is negligible, still belongs to steam with higher steam pressure, and is recovered through the steam recovery system to be returned to the primary reheating boiler 100 again, wherein one part still enters the primary reheating boiler in the form of steam, and the other part can enter the boiler water supply system to be recovered through high-pressure condensate formed after heat exchange with other heat exchange equipment (such as an evaporator and a preheater) in the steam generation system after pressurization, so that the loss of fire energy can be reduced and the first steam can be recycled in the recovery process.

Further preferably, the vapor recovery system includes a pressure matcher 700, the pressure matcher 700 having a fluid inlet, an ejector fluid inlet, and a mixed fluid outlet. The working fluid inlet of the pressure matcher 700 receives the intermediate steam, the mixed fluid outlet of the pressure matcher 700 is communicated with the low-pressure steam pipeline 130 of the primary reheating boiler 100, and the injection fluid inlet of the pressure matcher 700 can introduce steam with lower steam pressure than the low-pressure steam pipeline 130 (internal steam), or the injection fluid inlet is directly closed, and only the intermediate steam is depressurized and then is conveyed to the low-pressure steam pipeline 130 of the primary reheating boiler 100.

Further preferably, an injection fluid inlet on the pressure matcher 700 is configured to receive the second cooling steam, and the steam generating system is configured to receive the second steam and output the second cooling steam after heat exchange. The second cooling steam has a lower steam pressure than the intermediate steam.

The double heat sources are adopted to exchange heat with the steam generating system, and steam with a high pressure and a low pressure is generated after heat exchange or in the heat exchange process, and then is sent back to the low-pressure steam pipeline 130 of the primary reheating boiler 100 after being regulated by the pressure matcher 700.

Specifically, the thermal power generation and heat supply unit further comprises a steam turbine generator unit 200. The second steam is supplied to the steam generation system by the primary reheat boiler 100 or by the cylinders of the steam turbine generator set 200, thereby allowing the steam recovery system to recover the intermediate steam and the second cooling steam at the same time.

As shown in the drawing, a main steam pipe 110 and a high temperature reheat steam pipe 120 are connected between the primary reheat boiler 100 and the steam turbine generator unit 200. The low pressure steam line 130 of the primary reheat boiler 100 also communicates with the steam turbine generator set 200. The main steam line 110 is connected to the steam generating system to supply the first steam to the steam generating system. The high temperature reheat steam line 120 is connected to the steam generation system to provide the second steam to the steam generation system.

More specifically, the steam generation system includes a primary superheater 310 and a secondary superheater 320. The main superheater 310 and the sub superheater 320 each have a heat medium inlet, a heat medium outlet, a steam inlet and a steam outlet, wherein the heat medium inlet and the heat medium outlet are used for entering and exiting steam of a heat source, and the steam inlet and the steam outlet are used for entering and exiting steam of external heat supply. The primary superheater 310 and the secondary superheater 320 heat the lower temperature steam further into higher temperature superheated steam, i.e. the steam supplied by the steam generating system.

The heat medium inlet of the main superheater 310 communicates with the main steam pipe 110, and the main steam pipe 110 inputs the first steam to the heat medium inlet of the main superheater 310. After the main superheater 310 exchanges heat with the first steam, the heat medium outlet of the main superheater 310 can output the intermediate steam to the working fluid inlet of the pressure matcher 700, and the steam outlet of the main superheater 310 can output superheated steam, i.e., part of the steam output by the steam generation system for supplying heat to the outside.

The heat medium inlet of the auxiliary superheater 320 is communicated with the high-temperature reheat steam pipe 120, the high-temperature reheat steam pipe 120 inputs second steam to the heat medium inlet of the auxiliary superheater 320, after the auxiliary superheater 320 exchanges heat with the second steam, the heat medium outlet of the auxiliary superheater 320 can output the second cooling steam to the injection fluid inlet on the pressure matcher 700, the steam outlet of the auxiliary superheater 320 can output another superheated steam, and the superheated steam, namely, the steam generating system, outputs part of steam for supplying heat to the outside.

In particular implementations, the hot steam outlet of the primary superheater 310 outputs mixed superheated steam in parallel with the steam outlet of the secondary superheater 320.

In a further embodiment, the steam generation system further comprises an evaporator 410 and a drum 420, the evaporator 410 and drum 420 being capable of providing the lower temperature steam to the main superheater 310.

The steam drum 420 is a cylindrical container formed by welding steel plates, consists of a cylinder body and an end socket, and is pressure-bearing equipment capable of bearing steam pressure and water pressure. The cylinder of the drum 420 is provided with a down pipe, which is communicated with the evaporator 410, and the cylinder of the drum 420 stores liquid with a certain temperature for the evaporator 410 to consume in the process of generating steam.

The heat medium inlet of the evaporator 410 is communicated with the heat medium outlet of the main superheater 310, and the heat medium outlet of the main superheater 310 can deliver intermediate steam to the evaporator 410, so that after the evaporator 410 exchanges heat with the intermediate steam, the evaporator 410 can generate initial steam for supplying heat to the outside, that is, the lower temperature steam as described above, which is supplied to the steam inlet of the main superheater 310 or the steam inlet of the sub-superheater 320 via the steam outlet of the steam drum 420, respectively, so that the main superheater 310 and the sub-superheater 320 are further heated to superheated steam.

In this embodiment, the steam generation system further includes a heater 500, and the heater 500 is used to heat the liquid (water) and provide the liquid to the drum 420. The heat medium inlet of the heater 500 communicates with the heat medium outlet of the evaporator 410, so that the energy of the first steam can be fully utilized. The water outlet of the heater 500 is communicated with the water inlet of the drum 420 to supply hot water to the drum 420, and the water inlet of the heater 500 is supplied with deoxygenated water by a water supply line.

In this embodiment, the evaporator 410 is provided with an external condensate tank 430, and the condensate tank 430 is communicated with the evaporator 410. Meanwhile, the turbo generator set has a water supply pipeline, and the condensate tank 430 is connected to the water supply pipeline, and a condensate booster pump 650 is disposed on a connection pipeline between the two.

The supercooled cooling water, which is changed from the first steam after being used (a plurality of times) as a heat source, is generated by the heater 500. The pressure of the high-pressure water supply pipe 140 is increased by the condensate increasing pump 650. Then, they enter the high pressure water feed pipe 140 in the power plant steam-water cycle to mix, and finally enter the primary reheat boiler 100 to heat, forming the main steam, i.e. the high temperature and high pressure steam in the main steam pipe 110.

In the present embodiment, the primary steam side and the high temperature reheat steam side of the primary reheat boiler 100 each extract one steam, and exchange heat by the primary heat exchanger and the secondary heat exchanger, respectively. After the temperature of the main steam is lowered by heat exchange, the main steam is cooled and condensed into a condensate having a certain supercooling degree in the evaporator 410. Meanwhile, by arranging the external condensate tank 430, the vapor side and the condensate side of the evaporator 410 are respectively connected with the 430 vapor side and the condensate side of the condensate tank, the condensate tank is a vertical tank, the condensate tank has a certain volume, and the liquid level of the condensate tank is basically consistent with the liquid level of the heat source side of the evaporator 410, so that the heat exchange area of the evaporator on the heat source side condensate heat exchange tube is ensured, and the condensate outlet temperature of the evaporator is ensured to be constant.

At the same time, the condensate of the evaporator 410 is heated by the heater 500 to the saturation temperature by heating the deoxygenated water. During this heating process, the cooled condensate generated at the heat medium outlet of the heater 500 enters the condensate booster pump 650 to be boosted, and enters the water feed pipe of the turbo generator system to be merged. The combined feed water enters the boiler. In order to ensure a certain supercooling degree on the water inlet side of the condensate booster pump 650 and avoid cavitation of the condensate booster pump 650, a surge tank 440 is disposed in front of the condensate booster pump 650. A fourth pressure regulating valve 640 is provided in the condensate tank 430, and the fourth pressure regulating valve 640 can control the pressure of the surge tank 440. The pressure of the upper side of the surge tank 440 is controlled by the steam of the condensate tank 430 through the regulating valve, and the water side is connected with the condensate of the feedwater heater 500, so that the condensate has a certain liquid level and also maintains a certain pressure.

In this embodiment, the high-temperature reheat steam (i.e., the second steam) passes through the auxiliary superheater 320 and then enters the steam booster (i.e., the pressure matcher 700), the cooling steam is injected by the main steam cooling steam (i.e., the intermediate steam), and is boosted to a range matching with the pressure of the steam in the low-pressure reheat steam pipe by the steam booster, so that the low-temperature reheat steam enters, and the high-temperature reheat steam is formed by the reheater of the boiler.

The thermal power generation heat supply unit separates a boiler and a steam turbine, can simultaneously meet the requirements of heat supply and power generation of users, and simultaneously can independently adjust the power generation load by adjusting the main valve and the intermediate valve of the steam turbine when the boiler load is fixed (as long as the boiler load is ensured to be larger than the minimum steady combustion load), and adjusts the opening of an intermediate steam adjusting valve (namely a third pressure adjusting valve 630 in the figure) in front of an ejector through an adjusting valve 610 and an external heat supply heat source, so that the whole system and the whole system are flexible.

In order to achieve better adjustment, the steam generating system further includes a first pressure adjusting valve 610 disposed between the main steam pipe 110 and the main superheater 310, and the first pressure adjusting valve 610 can adjust the opening according to the pressure in the steam drum 420. When the pressure in the drum 420 is less than a preset value, the opening degree of the first pressure regulating valve 610 is increased. When the pressure in the drum 420 is greater than or equal to a preset value, the first pressure regulating valve 610 is maintained at a preset opening size.

For example, when the system is in operation, the primary reheat boiler 100 branches off from the primary steam header, a pressure regulating valve PCV1 (first pressure regulating valve 610, parameter 11.7mpa,540 ℃) is disposed on the steam header, the pressure regulating valve PCV1 is pressure-interlocked with the drum 420, that is, when the drum 420 pressure drops, the opening of the pressure regulating valve PCV1 increases, the flow rate of the primary steam (i.e., the first steam) entering is increased, the primary steam entering the system and the associated high temperature reheat steam increase, the heating steam source increases, the heating amount increases, the heat in the final drum 420 increases, the water in the evaporator 410 becomes more water vapor, and the pressure in the drum 420 increases.

It should be noted that, in order to achieve better adjustment, the steam generating system further includes a first temperature adjustment valve 660, where the first temperature adjustment valve 660 is disposed on a pipeline of the steam inlet of the auxiliary superheater 320, and the first temperature adjustment valve 660 can adjust the opening degree according to a comparison result between the steam temperature of the steam outlet of the main superheater 310 and the steam temperature of the steam outlet of the auxiliary superheater 320, so as to maintain the steam temperature difference between the steam outlets of the main superheater 310 and the auxiliary superheater 320 within a preset error range.

For example, in one embodiment, another path of cooling steam (intermediate steam) flows into the evaporator 410 (11.6 mpa,340 ℃), the saturated water (3.20 mpa,237.5 ℃) entering the evaporator 410 and heating the steam drum 420 is provided by the steam drum 420 through a down pipe, the heated steam-water mixture in the evaporator 410 enters the steam drum 420 through a rising pipe, the saturated steam enters the main superheater 310 and the auxiliary superheater 320 respectively through a pipe on the upper side of the steam drum 420, meanwhile, a first temperature regulating valve 660 is arranged on a steam pipe (i.e. a steam inlet) entering the auxiliary superheater 320, the first temperature regulating valve 660 is interlocked with the steam temperature (360 ℃) of a (steam) outlet of the auxiliary superheater 320, when the steam temperature of the steam outlet of the auxiliary superheater 320 is lower than the temperature of the steam outlet of the main superheater 310, the valve opening degree of the first temperature regulating valve 660 is reduced, the saturated steam passing through the auxiliary superheater 320 is reduced, and the temperature of the steam outlet of the auxiliary superheater 320 is increased to the temperature with the steam outlet of the main superheater 310; otherwise the opposite is true.

The heated steam from the evaporator 410 will be cooled to saturated water (11.5 mpa,321 c) during which time a significant amount of heat is evolved to heat the saturated water on the tube side of the evaporator 410, causing it to partially form saturated steam (3.2 mpa,237.5 c). One path of steam and one path of saturated water are respectively pulled out from the shell side (heat source side) and enter the condensate tank 430, so that the water level in the condensate tank 430 is consistent with the water level of the heat source at the shell side, the immersed area of the heat exchange tube at the shell side is ensured, and heat exchange is ensured.

In one embodiment, the steam generation system further includes a second pressure regulating valve 620 and a desuperheater 670. The second pressure regulating valve 620 and the desuperheater 670 are disposed on a pipeline for supplying heat after the steam outlet of the primary superheater 310 is connected in parallel with the steam outlet of the secondary superheater 320. Specifically, a second pressure regulating valve 620 and a desuperheater 670 are provided at the outlet steam side of the main superheater 310 and the sub superheater 320, the desuperheater 670 is provided with a cooling water source (3.4 mpa.185 ℃) from desuperheater water and a second temperature regulating valve 680, the second temperature regulating valve 680 is temperature-interlocked with the external heating steam (3.10 mpa,360 ℃) and the final temperature is controlled by the second temperature regulating valve 680. The second pressure regulating valve 620 and the second temperature regulating valve 680 are used as fine tuning of the external steam.

In an embodiment, the main steam (first steam) is cooled by the main heat exchanger to form steam (11.6 mpa,340 ℃), one path of steam (i.e. intermediate steam) enters the steam booster (i.e. pressure matcher 700) through a branch pipe to serve as a power steam source, a third pressure regulating valve 630 is arranged on the main steam (i.e. intermediate steam) and is interlocked with the pressure of the output side of the steam booster, the pressure of the third pressure regulating valve 630 is slightly higher than the pressure of the low-temperature reheat steam, the outlet steam of the third pressure regulating valve is ensured to enter a low-temperature reheat steam pipeline, the inner diameter of the steam booster is gradually reduced and then increased, the steam source steam flow speed is increased and the pressure is gradually reduced, the pressure is reduced to enable the cooling steam (i.e. second cooling steam) in the auxiliary superheater 320 to flow into the steam booster, and finally mixed steam is gradually increased to be slightly higher than the pressure of the low-temperature reheat steam (3.6 mpa,340 ℃), so that the cooling steam of the high-temperature reheat steam (3.30 mpa,540 ℃) flows into the low-temperature reheat steam (3.6 mpa,340 ℃). And mixing the rest low-temperature reheat steam, and finally heating the mixture through a boiler reheater to form high-temperature reheat steam. In this process, the intermediate steam of high quality is fully utilized to boost the pressure of the second cooling steam. The opening of the third pressure regulating valve 630 will affect the flow of high temperature reheat steam into the secondary superheater 320.

In an alternative embodiment, the steam generation system includes a three-way valve disposed on a line between the heat medium inlet of the secondary superheater 320, the high temperature reheat steam line 120, and a cylinder of the turbo generator set, the three-way valve enabling selective communication of the heat medium inlet of the secondary superheater 320 with one of the high temperature reheat steam line 120 and the cylinder of the turbo generator set.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that the present invention includes but is not limited to the accompanying drawings and the description of the above specific embodiment. Any modifications which do not depart from the functional and structural principles of the present invention are intended to be included within the scope of the appended claims.

Claims (17)

1. The thermal power generation heat supply unit comprises a primary reheating boiler and a steam generation system for supplying heat to the outside, and is characterized by further comprising a steam recovery system, wherein the primary reheating boiler is used for providing first steam required by heat exchange for the steam generation system, and the steam recovery system is used for recovering intermediate steam in the heat exchange process and reducing the pressure of the intermediate steam and returning the intermediate steam to a low-pressure steam pipeline of the primary reheating boiler; the ratio of the steam pressure of the intermediate steam to the steam pressure of the first steam is greater than or equal to a preset value, and the temperature of the intermediate steam is lower than the temperature of the first steam.

2. The thermal power generation and heating unit as recited in claim 1, wherein the steam recovery system includes a pressure matcher, a working fluid inlet on the pressure matcher receiving the intermediate steam, a mixed fluid outlet on the pressure matcher communicating with a low pressure steam conduit of the primary reheat boiler.

3. The thermal power generation and heating unit as recited in claim 2, wherein an ejector fluid inlet on the pressure matcher is configured to receive a second cooling steam, and the steam generation system is configured to receive the second steam and output the second cooling steam after heat exchange; the second cooling steam has a lower steam pressure than the intermediate steam.

4. A thermal power-generation-heating unit as defined in claim 3, further comprising a turbine-generator unit; one of the primary reheat boiler and the steam turbine generator set's cylinder is capable of providing the second steam for heat exchange to the steam generation system; the steam recovery system is capable of recovering the intermediate steam and the second cooling steam simultaneously.

5. The thermal power generation and heat supply unit according to claim 4, wherein a main steam pipeline is communicated between the primary reheating boiler and the steam turbine generator unit; the main steam line is connected with the steam generation system to provide the first steam to the steam generation system.

6. The thermal power generation and heating unit as recited in claim 5, wherein a high temperature reheat steam line is in communication between the primary reheat boiler and the steam turbine generator unit, the high temperature reheat steam line being connected to the steam generation system to provide the second steam to the steam generation system.

7. The thermal power generation and heating unit as recited in claim 6, wherein the steam generation system includes a main superheater, a heat medium inlet of which communicates with the main steam pipe so that after heat exchange with the first steam, a heat medium outlet of the main superheater can output the intermediate steam to a working fluid inlet on the pressure matcher, and a steam outlet of the main superheater can output steam for supplying heat to the outside.

8. The thermal power generation and heating unit of claim 7, wherein the steam generation system comprises a secondary superheater; the heat medium inlet of the auxiliary superheater is communicated with the high-temperature reheating steam pipeline, so that after heat exchange with the second steam, the heat medium outlet of the auxiliary superheater can output the second cooling steam to the injection fluid inlet on the pressure matcher, and the steam outlet of the auxiliary superheater can output steam for supplying heat to the outside.

9. The thermal power generation and heating unit of claim 8, wherein the steam generation system further comprises an evaporator and a steam drum; the steam drum is communicated with the evaporator; the heat medium inlet of the evaporator is communicated with the heat medium outlet of the main superheater so that after heat exchange with the intermediate steam, the evaporator can generate initial steam for supplying heat to the outside and supply the initial steam to the steam inlet of the main superheater or the steam inlet of the auxiliary superheater respectively through the steam outlet of the steam drum.

10. The thermal power generation and heating unit of claim 9, wherein the steam generation system further comprises a heater; the heat medium inlet of the heater is communicated with the heat medium outlet of the evaporator; the water outlet of the heater is communicated with the water inlet of the steam drum, and the heater can provide hot water for the steam drum.

11. The thermal power generation and heat supply unit according to claim 9, wherein an external condensate tank is arranged on the evaporator, and the condensate tank is communicated with the evaporator; the steam turbine generator unit is provided with a water supply pipeline, the condensate tank is connected with the water supply pipeline, and a condensate booster pump is arranged on a connecting pipeline between the condensate tank and the water supply pipeline.

12. The thermal power generation and heating unit as recited in claim 11, wherein the steam generation system further comprises a surge tank disposed between the condensate booster pump and the condensate tank; the condensate tank is provided with a fourth pressure regulating valve, and the fourth pressure regulating valve can control the pressure of the pressure stabilizing tank.

13. The thermal power generation and heating unit as recited in claim 9, wherein the steam generation system further comprises a first pressure regulating valve disposed between the main steam line and the main superheater, the first pressure regulating valve being capable of regulating an opening degree according to a pressure in the drum; when the pressure in the steam drum is smaller than a preset value, the opening of the first pressure regulating valve is increased; and when the pressure in the steam drum is larger than or equal to a preset value, the first pressure regulating valve is kept at a preset opening degree.

14. The thermal power generation and heating unit according to claim 9, wherein the steam generation system further comprises a first temperature adjustment valve provided on a pipe of the steam inlet of the sub-superheater, the first temperature adjustment valve being capable of adjusting an opening degree according to a comparison result of the steam temperature of the steam outlet of the main superheater and the steam temperature of the steam outlet of the sub-superheater so as to maintain a steam temperature difference between the steam outlets of the main superheater and the sub-superheater within a preset error range.

15. The thermal power generation and heating unit as recited in claim 9, wherein the steam outlet of the primary superheater is connected in parallel with the steam outlet of the secondary superheater to supply heat to the outside.

16. The thermal power generation and heating unit of claim 9, wherein the steam generation system further comprises a second pressure regulator valve and a desuperheater; the second pressure regulating valve and the desuperheater are arranged on a pipeline for supplying heat after the steam outlet of the main superheater is connected in parallel with the steam outlet of the auxiliary superheater.

17. The thermal power-generation and heating unit as recited in claim 16, wherein the steam generation system includes a three-way valve disposed on a line between the heat medium inlet of the secondary superheater, the high-temperature reheat steam line, and a cylinder of the turbo generator unit, the three-way valve being capable of selectively communicating the heat medium inlet of the secondary superheater with one of the high-temperature reheat steam line and the cylinder of the turbo generator unit.