阅读说明：本技术 一种凝结水混凝土储热灵活性调频系统及方法 (Flexible frequency modulation system and method for heat storage of condensed water concrete ) 是由 张振华 杜未 张浩峰 杨国强 周雅君 刘岩 梁文龙 高世杰 吴韬 胥佳瑞 李燕平 于 2020-06-17 设计创作，主要内容包括：本发明涉及一种凝结水混凝土储热灵活性调频系统及方法,该系统包括汽轮机、低压加热器、混凝土储热装置、除氧器、凝汽器、进汽调节阀；汽轮机低压抽汽口与低压加热器的蒸汽入口相连通；低压加热器水侧进出口与混凝土储热装置的进出口相连通；低压加热器水侧出口与除氧器的水侧入口相连通；低压加热器水侧入口与凝汽器的热水井出口相连通；混凝土储热装置水侧入口与凝汽器的热水井出口相连通；混凝土储热装置水侧出口与除氧器的水侧入口相连通；汽轮机的高压蒸汽入口与进汽调节阀出口相连通。本发明利用混凝土储热装置,可以作为进汽调节阀的辅助调频手段,增加一次调频的灵活性,而且减少进汽调节阀的节流损失,实现高效一次调频的作用。(The invention relates to a condensed water concrete heat storage flexibility frequency modulation system and a method, wherein the system comprises a steam turbine, a low-pressure heater, a concrete heat storage device, a deaerator, a condenser and a steam inlet regulating valve; the low-pressure steam extraction port of the steam turbine is communicated with the steam inlet of the low-pressure heater; the water side inlet and outlet of the low-pressure heater are communicated with the inlet and outlet of the concrete heat storage device; the water side outlet of the low-pressure heater is communicated with the water side inlet of the deaerator; the water side inlet of the low-pressure heater is communicated with the outlet of a hot water well of the condenser; the water side inlet of the concrete heat storage device is communicated with the outlet of a hot water well of a condenser; the water side outlet of the concrete heat storage device is communicated with the water side inlet of the deaerator; the high-pressure steam inlet of the steam turbine is communicated with the outlet of the steam inlet regulating valve. The invention utilizes the concrete heat storage device, can be used as an auxiliary frequency modulation means of the steam inlet regulating valve, increases the flexibility of primary frequency modulation, reduces the throttling loss of the steam inlet regulating valve and realizes the function of high-efficiency primary frequency modulation.)

1. A condensed water concrete heat storage flexibility frequency modulation system is characterized by comprising a steam turbine, a low-pressure heater, a concrete heat storage device, a deaerator, a condenser and a steam inlet regulating valve;

a low-pressure steam extraction port of the steam turbine is communicated with a steam inlet of the low-pressure heater through a steam pipeline; the water side inlet and outlet of the low-pressure heater are communicated with the inlet and outlet of the concrete heat storage device through a condensed water pipeline; the water side outlet of the low-pressure heater is communicated with the water side inlet of the deaerator through a pipeline; a water side inlet of the low-pressure heater is communicated with a hot water well outlet of the condenser through a condensed water pipeline;

a water side inlet of the concrete heat storage device is communicated with a hot water well outlet of the condenser through a pipeline; a water side outlet of the concrete heat storage device is communicated with a water side inlet of the deaerator through a pipeline; and a high-pressure steam inlet of the steam turbine is communicated with an outlet of the steam inlet regulating valve through a pipeline.

2. The system of claim 1, wherein the concrete heat storage device is a surface heat transfer device, and is made of water permeable concrete as heat storage base and heat exchange steel pipes arranged inside the concrete heat storage base.

3. The flexible frequency modulation system for heat storage of condensed water concrete according to claim 2, wherein said water permeable concrete is impregnated with a low boiling point phase change medium.

4. The system of claim 3, wherein the heat exchange steel tube is made of 316L high-grade stainless steel; the heat exchange steel pipe is internally communicated with organic unit condensed water, and the outside of the heat exchange steel pipe is used for surface heat exchange with concrete and a phase change medium.

5. The condensed water concrete heat storage flexible frequency modulation system according to claim 4, wherein the outer surface of the concrete heat storage device is provided with a high thermal insulation layer.

6. A method of operating a flexible FM system for thermal storage of condensed water concrete as claimed in any one of claims 1 to 5, comprising:

when the output of a turbine unit needs to be increased, the condensed water entering the low-pressure heater is partially shunted to enter the concrete heat storage device, the squeezed steam is exhausted to return to the turbine for acting, the output of the turbine unit is rapidly increased, and meanwhile, the condensed water shunted to enter the concrete heat storage device is heated by the stored heat and is sent to a next-stage heater at the outlet of the low-pressure heater;

when the output of the unit needs to be reduced, the flow of the condensate water entering the low-pressure heater is increased to increase steam extraction and reduce the working steam of the steam turbine, the output of the unit is quickly reduced, and meanwhile, the increased flow of the condensate water circularly enters the concrete heat storage device from the outlet of the low-pressure heater to store heat.

Technical Field

The invention belongs to the technical field of thermal power generation, and particularly relates to a system and a method for flexibly adjusting frequency of condensed water concrete heat storage.

Background

The high-capacity high-parameter thermal power generating unit has the characteristics of high efficiency and energy conservation, and is a main power generating device in the power generation industry of China at present.

The large-capacity unit has larger peak regulation capacity, but the peak regulation operation usually adopts a steam inlet control valve throttling operation mode, and certain operation economy needs to be sacrificed.

Meanwhile, the thermodynamic system of the unit has certain heat storage capacity, but a typical designed power plant does not fully utilize the heat storage capacity of high-pressure water supply and low-pressure condensed water systems at the side of a turbine, and theoretically, the heat storage and peak regulation capacity of the part is not utilized.

Therefore, for the problems that the peak regulation of the current unit is aggravated and the general standard-reaching rate of the primary frequency modulation is prominent, economic and efficient peak regulation and primary frequency modulation methods need to be researched.

Disclosure of Invention

The invention aims to provide a condensed water concrete heat storage flexibility frequency modulation system and a method, wherein a bypass heat storage system of a low-pressure heater is arranged, the flow of condensed water entering the low-pressure heater is adjusted through bypass heat storage, so that the control of steam extraction is realized, the function of adjusting the output of a unit is achieved, and the system is used as an auxiliary measure for a steam turbine steam inlet adjusting valve to participate in primary frequency modulation, so that the steam inlet throttling loss is reduced and the flexibility of a primary frequency modulation adjusting means is increased while the response quality of the primary frequency modulation is improved.

The invention provides a condensed water concrete heat storage flexibility frequency modulation system, which comprises a steam turbine, a low-pressure heater, a concrete heat storage device, a deaerator, a condenser and a steam inlet regulating valve, wherein the low-pressure heater is arranged on the steam turbine;

a low-pressure steam extraction port of the steam turbine is communicated with a steam inlet of the low-pressure heater through a steam pipeline; the water side inlet and outlet of the low-pressure heater are communicated with the inlet and outlet of the concrete heat storage device through a condensed water pipeline; the water side outlet of the low-pressure heater is communicated with the water side inlet of the deaerator through a pipeline; a water side inlet of the low-pressure heater is communicated with a hot water well outlet of the condenser through a condensed water pipeline;

a water side inlet of the concrete heat storage device is communicated with a hot water well outlet of the condenser through a pipeline; a water side outlet of the concrete heat storage device is communicated with a water side inlet of the deaerator through a pipeline; and a high-pressure steam inlet of the steam turbine is communicated with an outlet of the steam inlet regulating valve through a pipeline.

Furthermore, the concrete heat storage device is a surface type heat transfer device, water permeable concrete is used as a heat storage base body, and a heat exchange steel pipe is arranged in the concrete heat storage device.

Further, the water permeable concrete is injected with a phase change medium with a low boiling point.

Further, the heat exchange steel pipe is made of 316L high-grade stainless steel; the heat exchange steel pipe is internally communicated with organic unit condensed water, and the outside of the heat exchange steel pipe is used for surface heat exchange with concrete and a phase change medium.

Furthermore, the outer surface of the concrete heat storage device is provided with a high heat insulation layer.

The invention also provides an operation method of the condensed water concrete heat storage flexible frequency modulation system, which comprises the following steps:

when the output of a turbine unit needs to be increased, the condensed water entering the low-pressure heater is partially shunted to enter the concrete heat storage device, the squeezed steam is exhausted to return to the turbine for acting, the output of the turbine unit is rapidly increased, and meanwhile, the condensed water shunted to enter the concrete heat storage device is heated by the stored heat and is sent to a next-stage heater at the outlet of the low-pressure heater;

when the output of the unit needs to be reduced, the flow of the condensate water entering the low-pressure heater is increased to increase steam extraction and reduce the working steam of the steam turbine, the output of the unit is quickly reduced, and meanwhile, the increased flow of the condensate water circularly enters the concrete heat storage device from the outlet of the low-pressure heater to store heat.

By means of the scheme, the condensation water concrete heat storage flexibility frequency modulation system and method are adopted, the concrete heat storage device can be used as an auxiliary frequency modulation means of the steam inlet regulating valve, the flexibility of primary frequency modulation is improved, the throttling loss of the steam inlet regulating valve is reduced, and the effect of efficient primary frequency modulation is achieved. For a typical 600MW unit, the primary frequency modulation power can be increased by 30%, the response time of the primary frequency modulation can be guaranteed to be within 2s on average, the response amplitude of 15s can reach 78% on average, the response amplitude of 30s can reach 95% on average, the stabilization time is smaller than 45s on average, and meanwhile, the throttling loss is reduced, and the coal consumption is reduced by 1.5 g/kWh.

The foregoing is a summary of the present invention, and in order to provide a clear understanding of the technical means of the present invention and to be implemented in accordance with the present specification, the following is a detailed description of the preferred embodiments of the present invention.

Drawings

FIG. 1 is a schematic structural diagram of a flexible frequency modulation system for heat storage of condensed water concrete according to the present invention.

Reference numbers in the figures:

1-a steam turbine; 2-a low pressure heater; 3-concrete heat storage devices; 4-a deaerator; 5-a condenser; 6-air inlet adjusting valve.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Referring to fig. 1, the embodiment provides a condensed water concrete heat storage flexibility frequency modulation system, which includes a steam turbine 1, a low-pressure heater 2, a concrete heat storage device 3, a deaerator 4, a condenser 5, a steam inlet regulating valve 6 and a connecting pipeline system thereof. A low-pressure steam extraction port of the steam turbine 1 is communicated with a steam inlet of the low-pressure heater 2 through a steam pipeline; the water side inlet and outlet of the low-pressure heater 2 are communicated with the inlet and outlet of the concrete heat storage device 3 through a condensed water pipeline; the water side outlet of the low-pressure heater 2 is communicated with the water side inlet of the deaerator 4 through a pipeline; a water side inlet of the low-pressure heater 2 is communicated with a hot water well outlet of the condenser 5 through a condensed water pipeline; a water side inlet of the concrete heat storage device 3 is communicated with a hot water well outlet of the condenser 5 through a pipeline; the water side outlet of the concrete heat storage device 3 is communicated with the water side inlet of the deaerator 4 through a pipeline; the high-pressure steam inlet of the steam turbine 1 is communicated with the outlet of the steam inlet regulating valve 6 through a pipeline.

For a typical steam turbine 1, a bypass system of low pressure heaters 2 is provided, and a concrete heat storage device 3 is used to store heat of a condensate system. The concrete heat storage device 3 adopts pervious concrete with high specific heat capacity, high heat conductivity coefficient and good heat storage performance as a heat storage matrix, the heat conductivity coefficient of the concrete is not lower than 2.5W/(m.K), the heat resistance is not lower than 150 ℃, and a certain number of high-efficiency heat exchange steel pipes are arranged in the concrete heat storage device to assemble the surface heat exchange device, so that the high-efficiency and low-cost solid heat storage device is realized. In addition, the water permeable concrete can be injected with a phase change medium with low boiling point to strengthen the heat storage carrier and the heat storage density. The high-efficiency tube heat steel tube can be made of 316L high-grade stainless steel, condensed water of a unit can be led into the tube, and the outside of the tube exchanges heat with concrete and a phase change medium on the surface. The outer layer of the whole concrete heat storage device 3 is provided with a heat insulation material with a certain thickness, so that the heat dissipation loss of the heat storage device is reduced.

When the output of the turbine 1 needs to be increased, the condensed water entering the low-pressure heater 2 is partially shunted to enter the concrete heat storage device 3, and because the amount of condensed water entering the low-pressure heater 2 is reduced, the extracted steam is squeezed and returned to the turbine 1 to do work, so that the output of the turbine is increased rapidly, and meanwhile, the condensed water shunted to enter the concrete heat storage device 3 is heated by the stored heat and is sent to the next-stage heater at the outlet of the low-pressure heater 2. For a typical 600MW unit, condensed water at about 200 and 400t/h and 40-70 ℃ can be branched into the concrete heat storage device 3.

When the output of the unit needs to be reduced, the flow of the condensate water entering the low-pressure heater 2 is increased to increase extraction steam and reduce the working steam of the steam turbine 1, the output of the unit is quickly reduced, and the increased flow of the condensate water circularly enters the concrete heat storage device 3 from the outlet of the low-pressure heater 2 to store heat.

The unit AGC and the primary frequency modulation signal are connected to the concrete heat storage device 3 and participate in the control of the amount of condensation water at the inlet and the outlet of the concrete heat storage device to synchronously adjust the output of the unit, and the unit AGC and the primary frequency modulation signal can be used as an auxiliary frequency modulation means of the steam inlet regulating valve 6 to increase the flexibility and the response quality of primary frequency modulation, thereby reducing the throttling loss of the steam inlet regulating valve and realizing the high-efficiency, energy-saving and flexible primary frequency modulation effect.

The condensed water concrete heat storage device system can be used as an auxiliary frequency modulation means of the steam inlet regulating valve 6, the flexibility of primary frequency modulation is improved, the throttling loss of the steam inlet regulating valve is reduced, the efficient primary frequency modulation effect is realized, for a typical 600MW unit, the primary frequency modulation power can be increased by 30%, the average response time of the primary frequency modulation can be ensured to be within 2s, the average response amplitude of 15s can reach 78%, the average response amplitude of 30s can reach 95%, the average stabilization time is less than 45s, and meanwhile, the throttling loss is reduced by 1.5 g/kWh.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, it should be noted that, for those skilled in the art, many modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.