阅读说明：本技术 一种纯凝机组宽负荷调峰系统及运行方法 (Wide-load peak regulation system of straight condensing unit and operation method ) 是由 郭容赫 蒋翀 谭袖 王政先 王健 柳桐 骆仁达 王丽萍 王羽 徐伟轩 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种纯凝机组宽负荷调峰系统及运行方法,包括锅炉、汽轮机高压缸、汽轮机中压缸、汽轮机低压缸、发电机、低压加热器、高压加热器和除氧器以及蓄热装置,汽轮机低压缸采用小于同容量的汽缸,解决了小容积流量叶片安全运行问题,利用低压缸出力小的特性,用电低谷时,汽轮机的最小技术出力可下调到机组额定容量的20%～30%；汽轮机高压缸和中压缸采用同容量的汽缸,并允许进汽压力超过额定压力5%,利用高压缸、中压缸的过负荷能力以及蓄热装置的蓄热能力,对低压缸少出力的部分进行了弥补,用电高峰时,汽轮机的最大技术出力可达到机组额定容量的100%。本发明系统简单、性能可靠,解决了纯凝汽轮机不能深度调峰的问题。(The invention discloses a wide load peak regulation system and an operation method of a straight condensing unit, and the system comprises a boiler, a high-pressure cylinder of a steam turbine, a medium-pressure cylinder of the steam turbine, a low-pressure cylinder of the steam turbine, a generator, a low-pressure heater, a high-pressure heater, a deaerator and a heat storage device, wherein the low-pressure cylinder of the steam turbine adopts a cylinder with less than the same capacity, so that the safe operation problem of a small volume flow blade is solved, and the minimum technical output of the steam turbine can be reduced to 20-30% of the rated capacity of the unit by utilizing the characteristic of small output of the; the high-pressure cylinder and the intermediate pressure cylinder of the steam turbine adopt cylinders with the same capacity, the steam inlet pressure is allowed to exceed the rated pressure by 5%, the part with less output of the low-pressure cylinder is compensated by utilizing the overload capacity of the high-pressure cylinder and the intermediate pressure cylinder and the heat storage capacity of the heat storage device, and the maximum technical output of the steam turbine can reach 100% of the rated capacity of a unit at the power consumption peak. The system is simple and reliable in performance, and solves the problem that the straight condensing turbine cannot deeply regulate the peak.)

1. The utility model provides a pure wide load peak shaving system of congealing unit which characterized in that: comprises a boiler (1), a high-pressure steam turbine cylinder (2), a medium-pressure steam turbine cylinder (3), a low-pressure steam turbine cylinder (4), a generator (5), a low-pressure heater (6), a high-pressure heater, a deaerator (7) and a heat storage device (8), wherein the high-pressure steam turbine cylinder (2), the medium-pressure steam turbine cylinder (3), the low-pressure steam turbine cylinder (4) and the generator (5) are sequentially connected, the high-pressure steam turbine cylinder (2) is respectively connected with the boiler (1) through a main steam pipe (9) and a high-pressure steam exhaust pipe (11), the medium-pressure steam turbine cylinder (3) is connected with the boiler (1) through a reheating steam pipe (10), the medium-pressure steam turbine cylinder (3) is also connected with the low-pressure steam turbine cylinder (4) through a medium-pressure steam exhaust pipe (12), the medium-pressure steam exhaust pipe (12) is connected with a medium-pressure steam exhaust pipe branch pipe (13), and the medium-, steam turbine low pressure jar (4), low pressure feed water pipe (15) and boiler feed water pipe (16) are connected gradually through low pressure feed water pipe (14), condensate water pipe (15) and boiler (1) to steam turbine low pressure jar (6), low pressure feed water pipe (6) are still gone out vapour/water pipe (17) through heat accumulation device and are connected with heat accumulation device (8), and low pressure feed water pipe (18) are still pressed with steam turbine low pressure jar (4) through low pressure feed water pipe (6) simultaneously.

2. The wide load peak-shaving system of the straight condensing unit according to claim 1, characterized in that: a first valve (19) is installed on the main steam pipe (9), and a second valve (20) is installed on the reheating steam pipe (10).

3. The wide load peak-shaving system of the straight condensing unit according to claim 1, characterized in that: and a third valve (21) is arranged on the medium-pressure steam exhaust pipe (12), and a fourth valve (22) is arranged on the medium-pressure steam exhaust pipe branch pipe (13).

4. The wide load peak-shaving system of the straight condensing unit according to claim 1, characterized in that: and a fifth valve (23) is installed on the steam/water outlet pipe (17) of the heat storage device, and a sixth valve (24) is installed on the steam extraction pipe (18) of the low-pressure heater.

5. The wide load peak-shaving system of the straight condensing unit according to claim 1, characterized in that: the steam turbine high-pressure cylinder (2) and the steam turbine intermediate-pressure cylinder (3) adopt cylinders with the same capacity, the steam inlet pressure is allowed to exceed the rated pressure by 5%, and the steam turbine low-pressure cylinder (4) adopts cylinders with the capacity smaller than that of the steam turbine high-pressure cylinder (2) and that of the steam turbine intermediate-pressure cylinder (3); the maximum through-flow capacity of the steam turbine high-pressure cylinder (2) is matched with that of the steam turbine medium-pressure cylinder (3), and the maximum through-flow capacity of the steam turbine low-pressure cylinder (4) is not matched.

6. The wide load peak-shaving system of the straight condensing unit according to claim 1 or 5, characterized in that: the length of last stage blade in steam turbine low pressure jar (4) possesses maximum volume flow throughput, can be in the safe operation under little volume flow operating mode simultaneously, little volume flow operating mode is: steam flows through the high-pressure turbine cylinder (2) and the medium-pressure turbine cylinder (3) and enters the low-pressure turbine cylinder (4), the volume flow discharged by the last-stage blade is minimum, and the work capacity of the steam in each cylinder reaches a preset minimum load.

7. A method for operating the wide load peak-shaving system of the straight condensing unit according to any one of claims 1 to 6, characterized in that: the operation method comprises the following steps:

1) in the load valley period, the operation condition of the boiler (1) and the operation condition of the heat storage device (8) are adjusted, namely the opening of a valve I (19) is adjusted, the valve I (19) is closed, the flow of main steam is reduced, a valve II (20), a valve III (21) and a valve III (24) are fully opened, a valve IV (22) and a valve V (23) are closed, the share of the steam acting in a steam turbine high pressure cylinder (2), a steam turbine intermediate pressure cylinder (3) and a steam turbine low pressure cylinder (4) is reduced, the power generation load is reduced, and the requirement of power grid depth peak regulation in the valley period is met;

2) during the peak period of load, the share of steam doing work in a high-pressure turbine cylinder (2), a medium-pressure turbine cylinder (3) and a low-pressure turbine cylinder (4) is increased by adjusting the operation condition of a boiler (1), the operation condition of a heat storage device (8) and the operation condition of a low-pressure heater (6), namely adjusting the opening of a valve I (19), opening a valve I (19), increasing the flow of main steam, fully opening a valve II (20) and a valve III (21), when the steam exhaust flow of the medium-pressure turbine cylinder (3) is greater than the maximum steam inlet flow of the low-pressure turbine cylinder (4), opening a valve IV (22), sending the redundant part of steam into the heat storage device (8) for heat exchange and storage, opening a valve V (23), introducing the heat in the heat storage device (8) into the low-pressure heater (6) for heat release, and maintaining the balance of steam/water flow of the system, or closing the valve six (24) to cut off the low-pressure heater (6), or partially cutting off the high-pressure heater, so that the work-applying capacity of the steam turbine is increased, and the power grid load requirement in the peak period is met;

3) in the load balancing period, the operation condition of the boiler (1), the operation condition of the heat storage device (8) and the operation condition of the low-pressure heater (6) are adjusted, namely the opening degree of a valve I (19) is adjusted, the flow of main steam is adjusted, a valve II (20) and a valve III (21) are fully opened, a valve IV (22) is closed, a valve VI (24) is opened, a valve V (23) is opened, heat stored in the heat storage device (8) is released to the low-pressure heater (6), and in order to maintain the steam/water balance of the system, low-temperature water in the low-pressure heater (6) can be introduced into the heat storage device (8) for storage, so that the power grid load requirement in the load balancing period is met.

Technical Field

The invention belongs to the technical field of peak regulation of a straight condensing unit of a thermal power plant, and particularly relates to a wide-load peak regulation system of a straight condensing unit and an operation method thereof, which are particularly suitable for peak regulation requirements of large peak-valley difference of a power grid, and the load of the unit can be up and down.

Background

The power supply structure of China is mainly based on thermal power, the power supply structure is single, new energy represented by the wind power is rapidly increased in recent years, new energy resources are effectively consumed, the load rate of a thermal power unit is reduced, the peak regulation depth of the thermal power unit is increased, and full-load operation working conditions of partial regions are difficult to meet. Under the trend that the peak-to-valley difference of a power grid is gradually increased and new energy power generation has the characteristics of intermittence, randomness and uncontrollable performance, great difficulty is brought to peak regulation of a thermal power generating unit, and the power system has insufficient regulation capacity. For stable and reliable power supply of the frequency of a power protection network, a thermal power generating unit is required to be capable of carrying out deep peak shaving in the electricity consumption valley period, and has peak shaving capacity in the electricity consumption peak period, and the load of the unit can be up and down.

The thermal power coal-fired unit in China is designed according to the load of more than 70%, the peak regulation capacity of a domestic straight condensing unit reaches 50%, the situation causes insufficient flexibility of a power grid, when new energy is more output, the new energy is limited by the peak regulation capacity of the thermal power unit in the power grid, the new energy cannot be completely consumed, and the problems of relatively serious wind abandoning, light abandoning and water abandoning appear in partial areas. In order to promote the consumption of renewable energy, auxiliary service market operation rules are provided in various places in succession, the peak regulation compensation force is increased, the thermal power generating unit is encouraged to carry out deep peak regulation, but the unit which should bear the basic load carries out deep peak regulation, so that the economy of the unit is greatly reduced, the safe operation of the unit is influenced, the unit is seriously burdened, even equipment is damaged, and the service life of the unit is greatly shortened. The frequent occurrence of accidents in recent years, particularly the erosion and damage of the last stage blade of the low pressure cylinder, is caused by the serious accidents.

When the high-load operation is carried out, high-temperature and high-pressure steam sequentially flows through the high-pressure cylinder and the medium-pressure cylinder, is discharged through the medium-pressure cylinder and completely enters the low-pressure cylinder, when the steam reaches the next final stage and the final stage of the low-pressure cylinder, the steam pressure and the temperature are reduced very low, the specific volume of the steam is increased greatly, the volume flow of the discharged steam is very large, and in order to enable the steam to be smoothly discharged from the low-pressure cylinder, the next final stage, particularly the final stage, needs to have enough through flow area, and needs to have the final.

During low-load operation, the last-stage blade of the low-pressure cylinder needs minimum steam to pass through so as to ensure the safe operation of the last-stage blade, otherwise, the last-stage blade can be negatively influenced: firstly, the steam does not work outwards, but consumes external work, the phenomenon of blowing occurs, the temperature of an exhaust cylinder rises, and the unit vibrates; the dynamic stress and the dynamic frequency of the blade are changed, and the operation with a large negative attack angle is easy to occur, so that the blade flutters, even the blade is broken; and thirdly, the content of water drops in the last-stage steam flow of the low-pressure cylinder is high, when backflow occurs, the water drops impact the outlet edge of the movable vane, and water erosion easily occurs on the last-stage vane.

When the length of the last stage blade of the low pressure cylinder is determined, and the last stage blade meets the requirement of a large load, the last stage blade of the low pressure cylinder cannot meet the requirement of a small load, and vice versa. The steam turbine designed according to the basic load has the advantages that the minimum technical output of the steam turbine can reach 30% of rated load theoretically, the minimum cooling steam flow of the last-stage blade of a low-pressure cylinder of the steam turbine and the minimum stable combustion of a boiler are limited in actual operation, in order to ensure the safe operation of the last-stage blade, the peak regulation capacity of a straight condensing unit is about 40%, and the peak regulation depth and width cannot meet the requirements of 'energy up and down' of the load of a power grid.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a pure condensing unit wide-load peak regulation system and an operation method which are reasonable in design and reliable in operation, so that the pure condensing unit wide-load peak regulation requirement is met on the premise of ensuring the safety of the last-stage blade of a low-pressure cylinder, and the unit load can be up and down.

The technical scheme adopted by the invention for solving the problems is as follows: the utility model provides a pure wide load peak shaving system of congealing unit which characterized in that: including boiler, steam turbine high pressure jar, steam turbine intermediate pressure jar, steam turbine low pressure jar, generator, low pressure feed water heater, high pressure feed water heater and oxygen-eliminating device and heat accumulation device, steam turbine high pressure jar, steam turbine intermediate pressure jar, steam turbine low pressure jar and generator connect gradually, the steam turbine high pressure jar is connected with the boiler through main steam pipe and high pressure exhaust steam pipe respectively, the steam turbine intermediate pressure jar is connected with the boiler through reheat steam pipe, the steam turbine intermediate pressure jar still is connected with steam turbine low pressure jar through the middling pressure exhaust steam pipe, the middling pressure exhaust steam pipe is connected with middling pressure exhaust steam pipe bleeder pipe, the middling pressure exhaust steam pipe bleeder pipe is connected with heat accumulation device, steam turbine low pressure jar, low pressure feed water heater, high pressure feed water heater and oxygen-eliminating device and boiler pass through low pressure feed water heater oral siphon, condensate water pipe and boiler feed water pipe and are connected gradually, low pressure feed water heater, and meanwhile, the low-pressure heater is also connected with the low-pressure cylinder of the steam turbine through a steam extraction pipe of the low-pressure heater.

Furthermore, a first valve is installed on the main steam pipe, and a second valve is installed on the reheating steam pipe.

Furthermore, a third valve is arranged on the medium-pressure steam exhaust pipe, and a fourth valve is arranged on the branch pipe of the medium-pressure steam exhaust pipe.

Furthermore, a fifth valve is arranged on the steam/water outlet pipe of the heat storage device, and a sixth valve is arranged on the steam extraction pipe of the low-pressure heater.

Further, the steam turbine high pressure cylinder and the steam turbine intermediate pressure cylinder adopt cylinders with the same capacity, the steam inlet pressure is allowed to exceed the rated pressure by 5%, and the steam turbine low pressure cylinder adopts a cylinder with the capacity smaller than that of the steam turbine high pressure cylinder and the steam turbine intermediate pressure cylinder; the maximum through-flow capacity of the high-pressure cylinder and the medium-pressure cylinder of the steam turbine are matched and are not matched with the maximum through-flow capacity of the low-pressure cylinder of the steam turbine. The mismatching of the maximum through-flow capacity means that steam flows through the high-pressure cylinder and the intermediate-pressure cylinder and enters the low-pressure cylinder through the intermediate-pressure steam exhaust pipe, and when the flow of the steam entering the low-pressure cylinder reaches the maximum, the steam enters the high-pressure cylinder and the intermediate-pressure cylinder and does not reach the maximum.

Further, the length of last stage blade in the steam turbine low pressure cylinder possesses maximum volume flow throughput, can be at the safe operation under little volume flow operating mode simultaneously, little volume flow operating mode is: steam flows through the high-pressure cylinder and the medium-pressure cylinder of the steam turbine and enters the low-pressure cylinder of the steam turbine, the volume flow discharged by the last-stage blade is minimum, and the work-doing capacity of the steam in each cylinder reaches the preset minimum load.

The operation method of the wide-load peak regulation system of the straight condensing unit is characterized in that: the operation method comprises the following steps:

1) in the load valley period, the operating condition of the boiler and the operating condition of the heat storage device are adjusted, namely the opening of the first valve is adjusted, the first valve is closed, the flow of main steam is reduced, the second valve, the third valve and the sixth valve are fully opened, the fourth valve and the fifth valve are closed, the share of the steam acting in a high-pressure cylinder of the steam turbine, a medium-pressure cylinder of the steam turbine and a low-pressure cylinder of the steam turbine is reduced, the power generation load is reduced, and the requirement of power grid depth peak regulation in the valley period is met;

2) during the peak load period, by adjusting the operation condition of the boiler, the operation condition of the heat storage device and the operation condition of the low-pressure heater, namely, the opening degree of the first valve is adjusted, the first valve is opened to be larger, the main steam flow is increased, the second valve and the third valve are fully opened, the share of the steam acting in a high pressure cylinder, a medium pressure cylinder and a low pressure cylinder of the steam turbine is increased, when the exhaust steam flow of the turbine intermediate pressure cylinder is larger than the maximum inlet steam flow of the turbine low pressure cylinder, opening the valve IV, sending the redundant steam into the heat storage device for heat exchange and storage, opening the valve V, introducing the heat in the heat storage device into the low pressure heater for heat release, and maintaining the balance of steam/water flow of the system, or closing the valve and cutting off the low-pressure heater or partially cutting off the high-pressure heater, so that the work-applying capacity of the steam turbine is increased, and the power grid load requirement in the peak period is met;

3) in the load balancing period, the opening of the first valve is adjusted, the flow of the main steam is adjusted, the second valve and the third valve are fully opened, the fourth valve is closed, the sixth valve is opened, the fifth valve is opened, the heat stored in the heat storage device is released to the low-pressure heater, the low-temperature water in the low-pressure heater can be introduced into the heat storage device to be stored in order to maintain the steam/water balance of the system, and the power grid load requirement in the load balancing period is met.

Compared with the prior art, the invention has the following advantages and effects: the system is simple, reliable in performance and low in manufacturing cost, and has feasibility, operability and innovativeness. After the invention is applied, the technical output of the steam turbine can be adjusted to 20-30% of the rated capacity of the unit at minimum and 100% of the rated capacity of the unit at maximum, thereby ensuring the safe operation of the last-stage blades of the unit, increasing the peak-shaving depth and width of the straight condensing unit, ensuring the load of the unit to be up and down and having higher practical value.

Drawings

FIG. 1 is a schematic diagram of the wide load peak-shaving system structure of the straight condensing unit of the present invention.

In the figure: the system comprises a boiler 1, a turbine high-pressure cylinder 2, a turbine intermediate-pressure cylinder 3, a turbine low-pressure cylinder 4, a generator 5, a low-pressure heater 6, a high-pressure heater and deaerator 7, a heat storage device 8, a main steam pipe 9, a reheating steam pipe 10, a high-pressure steam exhaust pipe 11, a medium-pressure steam exhaust pipe 12, a medium-pressure steam exhaust pipe branch pipe 13, a low-pressure heater water inlet pipe 14, a condensed water pipe 15, a boiler water supply pipe 16, a heat storage device steam/water outlet pipe 17, a low-pressure heater steam extraction pipe 18, a valve I19, a valve II 20, a valve III 21, a valve IV 22, a valve V23 and a valve.

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

Examples are given.

Referring to fig. 1, in this embodiment, a straight condensing unit wide load peak regulation system includes a boiler 1, a turbine high pressure cylinder 2, a turbine intermediate pressure cylinder 3, a turbine low pressure cylinder 4, a generator 5, a low pressure heater 6, a high pressure heater, a deaerator 7, and a heat storage device 8, where the turbine high pressure cylinder 2, the turbine intermediate pressure cylinder 3, the turbine low pressure cylinder 4, and the generator 5 are sequentially connected, the turbine high pressure cylinder 2 is connected to the boiler 1 through a main steam pipe 9 and a high pressure exhaust steam pipe 11, the turbine intermediate pressure cylinder 3 is connected to the boiler 1 through a reheat steam pipe 10, the turbine intermediate pressure cylinder 3 is further connected to the turbine low pressure cylinder 4 through an intermediate pressure exhaust steam pipe 12, the intermediate pressure exhaust steam pipe branch pipe 13 is connected to the heat storage device 8, the turbine low pressure cylinder 4, the low pressure heater 6, the high pressure heater, the deaerator 7, and the boiler 1 are connected to the low pressure heater water inlet pipe 14 through a low pressure, The condensed water pipe 15 and the boiler feed pipe 16 are connected in sequence, the low-pressure heater 6 is also connected with the heat storage device 8 through a heat storage device steam/water outlet pipe 17, and the low-pressure heater 6 is also connected with the steam turbine low-pressure cylinder 4 through a low-pressure heater steam extraction pipe 18.

Specifically, a first valve 19 is installed on the main steam pipe 9, a second valve 20 is installed on the reheat steam pipe 10, a third valve 21 is installed on the medium-pressure steam exhaust pipe 12, a fourth valve 22 is installed on the medium-pressure steam exhaust pipe branch pipe 13, a fifth valve 23 is installed on the heat storage device steam outlet/water pipe 17, and a sixth valve 24 is installed on the low-pressure heater steam extraction pipe 18.

In this embodiment, the steam turbine high pressure cylinder 2 and the steam turbine intermediate pressure cylinder 3 adopt cylinders with the same capacity, the steam inlet pressure is allowed to exceed the rated pressure by 5%, and the steam turbine low pressure cylinder 4 adopts a cylinder with a capacity smaller than that of the steam turbine high pressure cylinder 2 and the steam turbine intermediate pressure cylinder 3; the maximum through-flow capacities of the turbine high pressure cylinder 2 and the turbine intermediate pressure cylinder 3 are matched and are not matched with the maximum through-flow capacity of the turbine low pressure cylinder 4.

In this embodiment, the length of last stage blade among the steam turbine low pressure cylinder 4 possesses the maximum volume flow ability of passing through, can be simultaneously at the safe operation under little volume flow operating mode, and little volume flow operating mode is: the steam flows through the high-pressure turbine cylinder 2 and the intermediate-pressure turbine cylinder 3 and enters the low-pressure turbine cylinder 4, the volume flow discharged by the last-stage blades is minimum, and the work capacity of the steam in each cylinder reaches the preset minimum load.

In this embodiment, the operation method of the wide-load peak regulation system of the straight condensing unit includes the following steps:

1) in the load valley period, the operating condition of the boiler 1 and the operating condition of the heat storage device 8 are adjusted, namely the opening of the first valve 19 is adjusted, the first valve 19 is closed, the flow of main steam is reduced, the second valve 20, the third valve 21 and the sixth valve 24 are fully opened, the fourth valve 22 and the fifth valve 23 are closed, the share of the steam acting in the high-pressure steam turbine cylinder 2, the medium-pressure steam turbine cylinder 3 and the low-pressure steam turbine cylinder 4 is reduced, the power generation load is reduced, and the requirement of power grid depth peak regulation in the valley period is met;

2) during the peak period of load, the operating condition of the boiler 1, the operating condition of the heat storage device 8 and the operating condition of the low-pressure heater 6 are adjusted, namely the opening of the first valve 19 is adjusted, the first valve 19 is opened to increase the flow of main steam, the second valve 20 and the third valve 21 are fully opened to increase the share of the steam doing work in the high-pressure steam turbine cylinder 2, the medium-pressure steam turbine cylinder 3 and the low-pressure steam turbine cylinder 4, when the steam exhaust flow of the medium-pressure steam turbine cylinder 3 is greater than the maximum steam inlet flow of the low-pressure steam turbine cylinder 4, the fourth valve 22 is opened to send the redundant part of the steam into the heat storage device 8 for heat exchange and storage, the fifth valve 23 is opened to introduce the heat in the heat storage device 8 into the low-pressure heater 6 for heat release to maintain the balance of the steam/water flow of the system, or the sixth valve 24 is closed to, the power grid load requirement in the peak period is met;

3) in the load balancing period, the operation condition of the boiler 1, the operation condition of the heat storage device 8 and the operation condition of the low-pressure heater 6 are adjusted, namely the opening of the first valve 19 is adjusted, the flow of the main steam is adjusted, the second valve 20 and the third valve 21 are fully opened, the fourth valve 22 is closed, the sixth valve 24 is opened, the fifth valve 23 is opened, the heat stored in the heat storage device 8 is released to the low-pressure heater 6, in order to maintain the steam/water balance of the system, the low-temperature water in the low-pressure heater 6 can be introduced into the heat storage device 8 for storage, and the power grid load requirement in the load balancing period is met.

Those not described in detail in this specification are well within the skill of the art.

Although the present invention has been described with reference to the above embodiments, it should be understood that the scope of the present invention is not limited thereto, and that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention.