阅读说明：本技术 一种联合循环调峰调频的湿冷机组及其运行方法 (Wet cooling unit combining cyclic peak regulation and frequency modulation and operation method thereof ) 是由 许朋江 邓佳 赵亮 马汀山 居文平 程东涛 林轶 于 2021-07-05 设计创作，主要内容包括：本发明公开一种联合循环调峰调频的湿冷机组及其运行方法,包括湿冷机组和联合循环发电系统,湿冷机组和联合循环发电系统的电力输出端接电网,所述联合循环发电系统的给水入口接湿冷机组给水出口,联合循环发电系统的排汽口与湿冷机组的排汽口均连通湿冷机组的蒸汽冷凝装置；通过增设联合循环发电系统辅助大机调峰调频,增加了湿冷机组调节的手段和能力,减少湿冷机组汽轮机进汽调门的波动频率,提高了机组运行的安全性和经济性；通过联合循环CCS-BF与湿冷机组CCS-TF相结合的调节方式,有效缓解湿冷机组经济运行和调峰调频能力之间的矛盾,提高了湿冷机组在未来高频次宽负荷应用场景下的调节效率和调节的安全性,具有巨大节能潜力。(The invention discloses a wet cooling unit with combined cycle peak shaving and frequency modulation and an operation method thereof, wherein the wet cooling unit comprises a wet cooling unit and a combined cycle power generation system, the power output ends of the wet cooling unit and the combined cycle power generation system are connected with a power grid, a water supply inlet of the combined cycle power generation system is connected with a water supply outlet of the wet cooling unit, and a steam exhaust port of the combined cycle power generation system and a steam exhaust port of the wet cooling unit are both communicated with a steam condensing device of the wet cooling unit; the combined cycle power generation system is additionally arranged to assist the peak regulation and frequency modulation of the large turbine, so that the means and the capacity of the regulation of the wet cooling unit are increased, the fluctuation frequency of the steam inlet regulating valve of the steam turbine of the wet cooling unit is reduced, and the safety and the economy of the operation of the unit are improved; by means of the combined regulation mode of combined cycle CCS-BF and wet cooling unit CCS-TF, the contradiction between the economic operation and peak regulation and frequency modulation capabilities of the wet cooling unit is effectively relieved, the regulation efficiency and the regulation safety of the wet cooling unit in the future high-frequency secondary wide-load application scene are improved, and the combined cycle CCS-BF and wet cooling unit CCS-TF energy-saving regulation method has great energy-saving potential.)

1. The wet cooling unit is characterized by comprising a wet cooling unit and a combined cycle power generation system, wherein the power output ends of the wet cooling unit and the combined cycle power generation system are connected with a power grid (5), a water supply inlet of the combined cycle power generation system is connected with a water supply outlet of the wet cooling unit, and a steam exhaust port of the combined cycle power generation system and a steam exhaust port of the wet cooling unit are both communicated with a steam condensing device of the wet cooling unit.

2. The combined-cycle peak-and-frequency-modulated wet cooling unit as recited in claim 1, characterized in that the combined-cycle power generation system comprises a combined-cycle boiler (11), a combined-cycle turbine (13) and a combined-cycle generator (14) which are connected in sequence, wherein an inlet of the combined-cycle boiler (11) is used as a feed water inlet of the combined-cycle power generation system, and an exhaust port of the combined-cycle turbine (13) is used as an exhaust port of the combined-cycle power generation system.

3. A combined cycle peak and frequency modulated wet cooling unit according to claim 2, characterized in that the combined cycle turbine inlet throttle (12) and the combined cycle turbine exhaust throttle (21) are respectively arranged on the inlet pipeline and the exhaust pipeline of the combined cycle turbine (13).

4. The combined-cycle peak-shaving frequency-modulated wet cooling unit according to claim 1, wherein the unit capacity of the combined-cycle power generation system does not exceed 10 MW.

5. The combined cycle peak and frequency modulated wet chiller according to claim 1 wherein the wet chiller feed water outlet is adjusted to the feed water inlet line of the combined cycle power generation system.

6. Combined cycle peak and frequency modulated wet cooling unit according to claim 1, characterized in that pressure and temperature transmitters are provided at the steam inlet and the steam outlet of the combined cycle turbine (13).

7. The combined-cycle peak-and-frequency-modulated wet cooling unit as set forth in claim 1, wherein the exhaust port of the combined-cycle power generation system is further communicated with an external heat supply pipeline.

8. The operation method of the combined cycle peak-shaving frequency-modulation wet cooling unit based on any one of claims 1 to 7 is characterized in that when the load of the power grid changes, the combined cycle power generation system is preferentially used for load adjustment of the power grid (5), the combined cycle power generation system is adjusted by adopting a boiler following coordination control method CCS-BF, and when the output of the combined cycle steam turbine (13) cannot meet the adjustment requirement of scheduling, the steam turbine of the wet cooling unit is controlled by following coordination CCS-TF to adjust.

9. The operating method according to claim 8, characterized in that when the load of the power grid (5) increases or the supply of new energy decreases, the load regulation of the power grid (5) is preferentially engaged by the combined cycle power generation system, and when the maximum output of the combined cycle turbine (13) cannot meet the regulation requirement of the scheduling, the load increase regulation is performed by the turbine-following coordination control CCS-TF of the wet cooling unit.

10. The operating method according to claim 8, characterized in that when the load of the power grid (5) is reduced or the supply of new energy is increased, the load regulation of the power grid (5) is preferentially engaged by the combined cycle power generation system, and when the minimum output of the combined cycle turbine (13) cannot meet the regulation requirement of the dispatching, the load reduction regulation is performed by the turbine-following coordination control CCS-TF of the wet cooling unit.

Technical Field

The invention belongs to the field of power station boilers and steam turbine systems, and particularly relates to a wet cooling unit combining cyclic peak shaving and frequency modulation and an operation method thereof.

Background

The conventional automatic control system respectively controls a boiler and a steam turbine, the steam turbine generally adjusts the rotating speed and the load of a unit, and the boiler adjusts the main steam pressure. From the control perspective, the boiler and the steam turbine are observed, wherein the boiler is an object with a large time constant and slow change, and the steam turbine is an object with a short time and fast change. With the continuous increase of the capacity of the unit set, the increase of the capacity of the power grid and the improvement of the frequency modulation and peak shaving requirements of the power grid, the conventional control system is difficult to meet the requirements of the thermal power unit set on both quick response to load change and stable operation parameters. The change of the load of the unit is necessarily reflected to the change of the main steam pressure of the unit, so that the boiler and the steam turbine must be regarded as a unified control object to carry out coordination control, wherein the coordination control refers to coordinating the working states of the boiler and the steam turbine through a control loop and simultaneously giving an instruction to a control system of the boiler and the steam turbine so as to achieve the purposes of quickly responding to the load change and stabilizing the operation parameters (mainly the pressure before the unit). The Coordinated Control System (CCS) comprises a machine and furnace main control system, each automatic control subsystem of the boiler and a steam turbine control system, wherein the machine and furnace main control system is the core of the CCS, and each subsystem of the boiler and the steam turbine control system are the execution stage of the CCS.

Because the coordinated control system must control two parameters of the unit load and the main steam pressure at the same time, the tasks borne by the boiler and the steam turbine must be divided into one part and the two parameters are ensured to be controlled. According to different tasks undertaken by a boiler and a steam turbine, the method is divided into two coordination control modes: one method is that the power of the unit is controlled by a boiler combustion rate regulating valve, and the front pressure of the machine is controlled by a steam inlet quantity regulating valve of a steam turbine, and is called a turbine following coordination control method (CCS-TF). The other method is that the power of the unit is controlled by a steam inlet quantity regulating valve of a steam turbine, and the front pressure of the machine is controlled by a boiler combustion rate regulating valve, and is called as a boiler following coordination control method (CCS-BF). The two characteristics are different, the load response of the former is poor, but the unit operates stably; the latter has fast load response, but large energy loss, and the operation stability of the unit is relatively poor due to the large inertia and delay of the boiler, which is characterized in that the main steam pressure has large fluctuation, the faster the response speed of the unit to the load demand is, the larger the fluctuation amplitude is, and the larger the valve regulation loss is.

The wet cooling unit occupies a large proportion in the coal-fired generator set due to the advantages of low manufacturing cost, low back pressure, good running economy and the like. At present, in order to improve the load response speed of the unit, a boiler following coordination control method (CCS-BF) is mostly adopted by a wet cooling unit. For the CCS-BF control method, in order to reduce the fluctuation range of the pressure in front of the engine and reduce the valve regulation loss, the following control strategies are mostly adopted aiming at the reason causing large fluctuation range: the control effect of the combustion rate of the boiler is strengthened so as to compensate the great inertia and delay of the boiler as much as possible. With the acceleration development of the installed capacity of new energy (photovoltaic, wind power), the new energy such as photovoltaic, wind power and the like has the characteristics of intermittence and instability, so that the adjustment task of the thermal power generating unit is obvious, and the method has important significance on how to improve the adjustment efficiency of the wet cooling unit in the future high-frequency wide-load scene.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a wet cooling unit with combined cycle peak-shaving frequency modulation and an operation method thereof, a combined cycle boiler, a combined cycle turbine and a small generator system thereof can be additionally arranged on the wet cooling unit to assist the peak-shaving frequency modulation of the unit, the means and the capability of the peak-shaving frequency modulation of the wet cooling unit are increased, the contradiction between the economic operation and the peak-shaving frequency modulation capability of the wet cooling unit is effectively relieved, the regulation efficiency and the regulation safety of the wet cooling unit in the future high-frequency wide-load application scene are improved, and the energy-saving potential is huge.

In order to achieve the purpose, the invention adopts the technical scheme that: the wet cooling unit comprises a wet cooling unit and a combined cycle power generation system, wherein the power output ends of the wet cooling unit and the combined cycle power generation system are connected with a power grid, a water supply inlet of the combined cycle power generation system is connected with a water supply outlet of the wet cooling unit, and a steam outlet of the combined cycle power generation system and a steam outlet of the wet cooling unit are both communicated with a steam condensing device of the wet cooling unit.

The combined cycle power generation system comprises a combined cycle boiler, a combined cycle steam turbine and a combined cycle power generator which are sequentially connected, wherein an inlet of the combined cycle boiler is used as a water supply inlet of the combined cycle power generation system, and an exhaust port of the combined cycle steam turbine is used as an exhaust port of the combined cycle power generation system.

And the inlet pipeline and the exhaust pipeline of the combined cycle turbine are respectively and correspondingly provided with a combined cycle turbine steam inlet regulating valve and a combined cycle turbine exhaust valve.

The unit capacity of the combined cycle power generation system does not exceed 10 MW.

And a water supply outlet of the wet cooling unit is connected with a water supply inlet pipeline of the combined cycle power generation system through an upper adjusting valve.

Pressure and temperature transmitters are arranged at a steam inlet and a steam outlet of the combined cycle steam turbine.

And the steam outlet of the combined cycle power generation system is also communicated with an external heat supply pipeline.

According to the operation method of the combined cycle peak shaving frequency modulation wet cooling unit, when the load of a power grid changes, the combined cycle power generation system is preferentially used for participating in load adjustment of the power grid, the combined cycle power generation system is adjusted by adopting a boiler following coordination control method CCS-BF, and when the output of a combined cycle steam turbine cannot meet the adjustment requirement of scheduling, the steam turbine of the wet cooling unit is used for following coordination control CCS-TF for adjustment.

When the load of a power grid is increased or the power supply amount of new energy is reduced, the combined cycle power generation system is preferentially used for participating in load adjustment of the power grid, and when the maximum output of the combined cycle steam turbine cannot meet the adjustment requirement of scheduling, the steam turbine of the wet cooling unit is used for carrying out load increase adjustment by following and coordinately controlling the CCS-TF.

When the load of the power grid is reduced or the power supply amount of new energy is increased, the combined cycle power generation system is preferentially used for participating in load adjustment of the power grid, and when the minimum output of the combined cycle steam turbine cannot meet the adjustment requirement of scheduling, the steam turbine of the wet cooling unit is used for carrying out load reduction adjustment by means of coordinated control CCS-TF.

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

(1) by additionally arranging the combined cycle power generation system to assist the peak regulation and frequency modulation of the large turbine, the method and the capacity of the wet cooling unit are increased, the fluctuation frequency of the steam inlet regulating valve of the steam turbine of the wet cooling unit is reduced, and the safety and the economical efficiency of the unit operation are improved.

(2) By means of the combined regulation mode of combined cycle CCS-BF and wet cooling unit CCS-TF, the contradiction between the economic operation and peak and frequency regulation capacity of the wet cooling unit is effectively relieved, the regulation efficiency and the regulation safety of the wet cooling unit in the future high-frequency secondary wide-load application scene are improved, and the combined cycle CCS-BF and wet cooling unit CCS-TF energy-saving regulation method has great energy-saving potential.

(3) The combined cycle power generation system is high in reliability, flexible in operation, simple in operation and strong in usability.

Drawings

FIG. 1 is a schematic diagram of a combined cycle peak and frequency modulated wet cooling unit of the present invention;

in the figure, 1, a boiler, 2, a turbine steam inlet valve, 3, a turbine, 4, a generator, 5, a power grid, 6, a power consumer, 7, a natural draft cooling tower, 8, a circulating water pump, 9, a condenser, 10, a water feed pump, 11, a combined cycle boiler, 12, a combined cycle turbine steam inlet valve, 13, a combined cycle turbine, 14, a combined cycle generator, 15, a pump outlet valve, 16, a pump inlet valve, 17, a condenser outlet valve, 18, a condenser inlet valve, 19, a pump outlet valve, 20, a pump inlet valve, and 21 are combined cycle turbine exhaust valves.

Detailed Description

The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, and it should be understood that the preferred embodiments described herein are merely for purposes of illustration and explanation and are not intended to limit the present invention.

Referring to fig. 1, a combined cycle peak shaving wet cooling unit comprises a wet cooling unit and a combined cycle power generation system, wherein the power output ends of the wet cooling unit and the combined cycle power generation system are connected with a power grid 5, a water supply inlet of the combined cycle power generation system is connected with a water supply outlet of the wet cooling unit, and a steam outlet of the combined cycle power generation system and a steam outlet of the wet cooling unit are both communicated with a steam condensing device of the wet cooling unit; the combined cycle power generation system comprises a combined cycle boiler 11, a combined cycle steam turbine 13 and a combined cycle generator 14 which are sequentially connected, wherein an inlet of the combined cycle boiler 11 is used as a water supply inlet of the combined cycle power generation system, and an exhaust port of the combined cycle steam turbine 13 is used as an exhaust port of the combined cycle power generation system; the inlet pipeline and the steam exhaust pipeline of the combined cycle turbine 13 are respectively and correspondingly provided with a combined cycle turbine steam inlet regulating valve 12 and a combined cycle turbine steam exhaust valve 21; the outlet of the water feeding pump 10 is provided with a pump outlet door 15, the inlet of the water feeding pump 10 is provided with a pump inlet door 16, the water feeding pump 10 sends high-pressure feed water into the combined cycle boiler 11 and the boiler 1, the high-pressure feed water passes through the combined cycle boiler 11 and the boiler 1 to become qualified main steam, the main steam respectively and correspondingly enters the combined cycle turbine 13 and the steam turbine 3 to do work, and the exhaust steam of the combined cycle turbine 13 and the steam turbine 3 enters the condenser 8 to be condensed and then continues to enter the high-pressure feed water circulation; the combined cycle turbine 13 and the turbine 3 drive the combined cycle generator 14 and the generator 4 to generate power and merge into the power grid 5, and the power is transmitted to the power consumer 6 through the power grid 5.

The unit capacity of the combined cycle power generation system does not exceed 10 MW.

And a water supply outlet of the wet cooling unit is connected with a water supply inlet pipeline of the combined cycle power generation system through an upper adjusting valve.

Pressure and temperature transmitters are arranged at the steam inlet and the steam outlet of the combined cycle steam turbine 13.

And the steam outlet of the combined cycle power generation system is also communicated with an external heat supply pipeline.

Working example 1

A330 MW subcritical single-intermediate reheating double-cylinder double-steam-exhaust single-shaft condensing steam turbine generator unit is N310-16.7/538/538 in model number, and under the working condition of VWO, the main steam pressure is 16.7MPa, the main steam temperature is 538 ℃, the reheating steam temperature is 538 ℃, the low-pressure cylinder steam inlet pressure is 0.802MPa, and the low-pressure cylinder steam inlet temperature is 347.067 ℃. The wet cooling unit adopts a boiler following coordination control method (CCS-BF), can realize quick response of the unit to a load demand instruction, but can cause great fluctuation of the pressure in front of the unit at the same time, and the energy loss is increased. New energy such as photovoltaic, wind-powered electricity generation have intermittent type nature and the characteristic of unstability, and the new energy (photovoltaic, wind-powered electricity generation) installed capacity acceleration development in recent years, therefore the regulation task of thermal power unit is obvious. Under the condition, the examination pressure of the grid-connected thermal power enterprise is increased under the condition that the AGC load instruction of the power grid frequently changes. The load regulation capacity of the unit is reduced, the actual load cannot follow the AGC instruction, the boiler combustion is unstable, the temperature change of main and reheated steam is severe, and the safe and stable operation of equipment is greatly influenced.

The combined cycle peak-load-adjusting frequency-modulating wet cooling unit is implemented by adding a combined cycle steam turbine, a boiler and a small generator system thereof, the final feed water of a large unit is divided into two parts, one part is fed to the boiler, the other part is fed to the combined cycle boiler and the steam turbine system thereof, the exhaust steam of the combined cycle steam turbine is directly discharged into a steam condensing device of the large steam turbine, the power of the large unit is not influenced, the adjusting and controlling mode of the wet cooling unit is changed into a steam turbine coordinated control CCS-TF to reduce the energy loss, the combined cycle steam turbine adopts the adjusting mode of the boiler coordinated control CCS-BF to preferably meet the scheduling requirement of a power grid through the adjustment of the combined cycle power generation system, and the combined cycle power generation system is small in size and small in inertia, so that the load response is fast, the pressure fluctuation in front of the combined cycle steam turbine is relatively small, and the energy loss is relatively small. When the maximum output of the combined cycle power generation system cannot meet the regulation requirement of dispatching, the regulation is carried out through the regulation system of the cold unit, and the integral efficient economic regulation of the unit is ensured.

VWO, the inlet pressure of the combined cycle turbine is 5MPa, the inlet temperature is 300 ℃, and the inlet volume of the combined cycle turbine can be adjusted according to the operation requirement.

The operation mode of the adjustment process and the implementation system of the combined cycle wet cooling unit is as follows:

1. when the load of the power grid 5 is increased or the power supply amount of new energy (wind power and photovoltaic) is reduced, the combined cycle power generation system is preferentially used for participating in load adjustment of the power grid 5, the boiler following coordination control method CCS-BF is adopted by the combined cycle power generation system, the main control load of the combined cycle steam turbine is increased, the combined cycle boiler follows and controls the pressure in front of the combined cycle steam turbine, the combined cycle power generation system is small, the inertia is small, the load response is fast, the pressure fluctuation in front of the combined cycle steam turbine 13 is relatively small, and the energy loss is relatively small. When the combined cycle system can not meet the regulation requirement of dispatching, the steam turbine boiler of the wet cooling unit follows the coordination control CCS-TF to carry out load increase regulation.

2. When the load of the power grid 5 is reduced or the power supply quantity of new energy (wind power and photovoltaic) is increased, the combined cycle power generation system is preferentially used for participating in load adjustment of the power grid 5, the boiler following coordination control method CCS-BF is adopted by the combined cycle power generation system, the main control load of the combined cycle steam turbine is reduced, the combined cycle boiler follows and controls the pressure in front of the combined cycle steam turbine, the combined cycle power generation system is small, the inertia is small, the load response is fast, the pressure fluctuation in front of the combined cycle steam turbine 13 is relatively small, and the energy loss is relatively small. When the combined cycle system can not meet the regulation requirement of dispatching, the steam turbine of the wet cooling unit follows the coordination control CCS-TF to carry out load reduction regulation.

The combined cycle power generation system is additionally arranged to assist the peak regulation and frequency modulation of the large turbine, so that the means and the capacity of the regulation of the wet cooling unit are increased, the fluctuation frequency of the steam inlet regulating valve of the steam turbine of the wet cooling unit is reduced, and the safety and the economy of the operation of the unit are improved; by adopting an adjusting mode of combining combined cycle CCS-BF and wet cooling unit CCS-TF, the contradiction between the economic operation and peak and frequency adjusting capability of the wet cooling unit is effectively relieved, the adjusting efficiency and the adjusting safety of the wet cooling unit in the future high-frequency secondary wide-load application scene are improved, and the energy-saving potential is huge; the combined cycle power generation system is high in reliability, flexible in operation, simple in operation and strong in usability.