CN114776544A - High-temperature water heat storage photo-thermal power generation system - Google Patents

Abstract

A high-temperature water heat storage and photothermal power generation system includes a concentrating heat collecting unit, a heat storage unit, a power generating unit and a water medium circulation system. The light-converging and heat-collecting unit includes a condensing mirror, a heat absorber and a low-temperature water storage tank for water supply; the heat-storage unit is composed of a plurality of high-temperature and high-pressure water storage and heat storage tanks; the power generation unit includes a balance storage unit connected in sequence. Steam tanks, steam turbines, generators, condensers. The heat collection, heat exchange, heat storage and power generation of the high-temperature water heat storage CSP system are all completed by the water medium cycle, and high-temperature hot water is used as the medium for energy storage. The whole system has the advantages of simple structure, low cost, high efficiency, stability, and can generate peak power according to needs.

Description

High temperature water heat storage CSP system

technical field

The invention relates to the technical field of new energy, in particular to a high-temperature water heat storage photothermal power generation system.

Background technique

As a clean and renewable energy, solar energy has been paid more and more attention in today's increasingly scarce resources, and the technology of solar power generation and energy storage has also been paid more and more attention. At present, a common power generation method for solar power generation is photovoltaic power generation. Photovoltaic power generation is based on the principle of photovoltaic effect, using solar cells to directly convert sunlight energy into electrical energy. Regardless of whether it is used independently or connected to the grid, the photovoltaic power generation system is mainly composed of three parts: solar panels (components), controllers and inverters. Photovoltaic power generation has the advantages of extremely refined equipment, reliable stability, long service life, and easy installation and maintenance.

However, a major problem with solar energy is its instability. External weather conditions at different times will lead to large fluctuations in power generation, which have a great negative impact on grid-connected operation or matching with user needs.

Another common power generation method of solar power generation is CSP. CSP refers to the use of large-scale arrays of parabolic or dish mirrors to collect solar thermal energy, and to provide heat to the working medium through the heat exchange medium to form steam, and then to drive the traditional Turbine generator to achieve the purpose of generating electricity.

The use of solar thermal power generation technology avoids the expensive silicon photoelectric conversion process, which can greatly reduce the cost of solar power generation. Moreover, this form of solar energy can also store heat through a medium in a huge container, which can still drive a steam turbine to generate electricity a few hours after the sun goes down.

However, the current CSP uses molten salt or heat transfer oil as the heat exchange medium to provide heat to the working medium. Whether it is used in tower or trough power generation, it is used as a circulating medium. The use process is complicated, the application cost is high, and it is easy to corrode. equipment, it is difficult to find the ideal melting point molten salt; heat transfer oil is easy to age, high cost, and polluting, and both medium power generation requires secondary heat exchange, resulting in large energy loss. As a heat exchange work medium, water was first used in tower and trough solar thermal power generation, and in direct power generation, with the advantages of short process flow, high thermal efficiency and low cost. However, there is water as a heat storage medium, which requires a certain amount of heat storage under extremely high pressure conditions, so water heat storage has not been applied to CSP energy storage. At present, both tower and trough types are mainly based on molten salt and heat transfer oil for heat storage, and there are at least two to three heat exchanges for power generation. This leads to the complexity of the entire power generation system, low heat exchange efficiency, high cost, and high corresponding failure rate.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention proposes a high-temperature water heat storage photothermal power generation system to solve one or more technical problems existing in the above background technology, such as the energy of heat exchange between the heat exchange medium and the working medium The loss is large, the solar energy conversion efficiency is low, and the cost is high.

The present invention proposes the following technical solutions in order to solve the above-mentioned problems:

First, the water medium is used as the CSP system for heat absorption, heat transfer and heat storage. The above functions as the work medium are all completed by the water medium. Especially during the day when the solar energy is sufficient, the system directly generates high-temperature steam with high efficiency. Second, use hot water energy storage, for high temperature and high pressure water, use metal containers to store, and use small unit metal containers in parallel or in series to store hot water, metal containers can be made into cylindrical or spherical shape, so that It can solve the problem of the small capacity of the original hot water storage container.

In order to realize the above technical solution, the present invention provides a high-temperature water heat storage photothermal power generation system, which includes a concentrating heat collecting unit, a heat storage unit and a power generation unit;

The light concentrating and heat collecting unit includes a tracking condenser composed of a condenser lens and a tracking system, at least one heat absorber and a low temperature water storage, and each heat absorber has at least one corresponding tracking condenser to provide the concentrated solar light and heat, and the low temperature water storage. The outlets are respectively connected with the inlets of the corresponding heat sinks;

The heat storage unit includes a plurality of high temperature and high pressure water storage heat storage devices; the outlet of the heat absorber is communicated with the bottom end inlet of the high temperature and high pressure water storage heat storage device; the top outlet of the high temperature and high pressure water storage heat storage device is connected to the high pressure steam turbine. The inlet of the high temperature and high pressure water storage heat storage device is communicated with the outlet of the low temperature water storage device;

The power generation unit includes a steam turbine, a generator, a condenser, a cooling tower, and a balance steam storage tank. The inlet of the steam turbine is connected to the corresponding heat absorber outlet through the balance steam storage tank; the steam turbine outlet is connected to the generator to do work, and is connected to the condenser and the condenser. The cooling tower is communicated with each other, and the other end of the balance steam storage tank is communicated with the high temperature and high pressure water storage heat storage device.

The high-temperature and high-pressure water storage heat storage device is made of metal material, with a pressure resistance of 25MPa and a high temperature resistance of 370 degrees Celsius.

The condensed water storage is also provided with a vacuum pump for evacuation, and a cooling tower is provided outside the condenser to provide cooling capacity for the condenser.

The purified pure water is replenished from the water purification device to the low-temperature water storage device through a water pump and a valve; and then enters the heat absorber through a water pump, a valve and a flow control valve. The outlet of the heat absorber is provided with a sensor, and the sensor Control the flow rate of the flow control valve; in the heat sink, the water medium is heated into high temperature water, steam or superheated steam.

The water medium is heated in the heat absorber to generate steam to directly generate electricity. After entering the balance steam storage tank and the steam turbine through the valve, the steam turbine drives the generator to generate electricity. The low-temperature steam after power generation is condensed in the condenser as After the water is collected, it enters the condensed water storage and is transported to the low-temperature water storage through the water pump and valve to complete a direct power generation cycle.

During heat storage, the water medium is heated into steam or high-temperature water in the heat absorber, and the steam or high-temperature water enters the heat storage unit from the heat absorber to store thermal energy; The water in the high temperature and high pressure water storage heat storage device can also be sent to the heat absorber again through the water pump and valve for heating and transported back to the high temperature and high pressure heat storage device until the high temperature and high pressure water reaches the critical saturation state or control requirements.

The high temperature and high pressure water storage heat storage device is connected to one end of the balance steam storage tank, and the high temperature steam generated by the high temperature water in the high temperature and high pressure water storage heat storage device enters the steam turbine after passing through the balance steam storage tank, and drives the steam turbine to generate electricity. , the low-temperature steam after power generation is condensed into the condensed water storage, and re-transported to the low-temperature water storage by the water pump.

Compared with the prior art, the present invention has the following advantages: the high-temperature water heat storage photothermal power generation system of the present invention directly uses water as the heat exchange medium and the working medium at the same time, which can avoid the energy loss of the heat exchange between the heat exchange medium and the working medium. , improve heat utilization efficiency, and can also use high temperature and high pressure water medium for energy storage, which has the advantages of large scale, low cost, environmental protection, etc. It solves the problem of power peak regulation and energy storage, improves the efficiency, stability and safety of the power system, and achieves beneficial technical effects.

Description of drawings

Fig. 1 is the control flow chart of the power generation and energy storage process of the high-temperature water thermal storage CSP system of the present invention;

2 is a system topology diagram of the power generation and energy storage process of the present invention;

Fig. 3 is the control flow chart of the power generation process of the present invention;

4 is a system topology diagram of the power generation process of the present invention;

Fig. 5 is the control flow chart of the energy storage process of the present invention;

6 is a system topology diagram of an energy storage process of the present invention;

Fig. 7 is the control flow chart of the process of first storing energy and then generating electricity according to the present invention;

FIG. 8 is a system topology diagram of the process of first storing energy and then generating electricity according to the present invention.

Description of reference numbers:

1-1, 1-2-tracking condenser; 2-1, 2-2-heat absorber; 3-steam turbine; 4-condenser; 5-low temperature water storage; 6-generator; 7-high temperature and high pressure water storage Heater; 8-purifying water supplement; 9-cooling tower; 10-condensate storage; 11, 12, 13, 14-water pump; 15-vacuum pump; 21, 22-flow control valve; 23, 24, 25, 26, 27, 28, 29, 30, 33, 34, 35 - valve; 31, 32 - sensor; 40 - balance steam storage tank.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The high-temperature water heat storage photothermal power generation system of the present invention includes a condensing heat collecting unit, a heat storage unit and a power generating unit; the light concentrating heat collecting unit includes a condensing lens and a tracking condensing lens composed of a tracking system, at least one heat absorber and a low temperature Water storage, each heat absorber has at least one corresponding tracking condenser to provide concentrated solar light and heat, the outlet of the low-temperature water storage is respectively connected with the inlet of the corresponding heat absorber; the heat storage unit includes a plurality of high-temperature and high-pressure water storage units Heat storage device; the outlet of the heat absorber is communicated with the bottom end inlet of the high temperature and high pressure water storage heat storage device; the top outlet of the high temperature and high pressure water storage heat storage device is communicated with the inlet of the high pressure steam turbine; The other outlet is communicated with the outlet of the low-temperature water storage; the power generation unit includes a steam turbine, a generator, a condenser, a cooling tower, and a balance steam storage tank, and the inlet of the steam turbine is connected with the corresponding heat absorber outlet through the balance steam storage tank; the steam turbine The outlet is connected to the generator to do work, and communicated with the condenser and the cooling tower, and the other end of the balance steam storage tank is communicated with the high temperature and high pressure water storage heat storage device.

Referring to the high-temperature water heat storage photothermal power generation system of the present invention shown in FIGS. 1 and 2 , it includes a purifying water replenisher 8, a low-temperature water storage 5, a heat absorber 2-1, a balance steam storage tank 40, a steam turbine 3, a condensation 4 and condensate storage 10. The water outlet of the condensed water storage 10 is connected to the water inlet of the low temperature water storage 5 .

A water pump 11 and a valve 23 are arranged in sequence between the water purification device 8 and the low-temperature water storage 5, a water pump 12 and a valve 24 are arranged between the low-temperature water storage 5 and the heat absorber 2-1 in sequence, and the condensed water storage A water pump 14 and a valve 27 are arranged in sequence between the 10 and the low-temperature water storage 5 , and a valve 25 is arranged between the heat absorber 2 - 1 and the steam turbine 3 .

The other outlet of the low temperature water storage 5 is connected to the lower end inlet of the high temperature and high pressure water storage heat storage device 7 through the heat absorber 2-2, and the upper end outlet of the high temperature and high pressure water storage heat storage device 7 is connected to the inlet of the steam turbine 3 through the valve 26. The other outlet of the high temperature and high pressure water storage heat storage device 7 is connected to the heat absorber 2-2 through the water pump 13 and the valve 28 in sequence.

The condenser 1-1 provides heat Q1 to the heat absorber 2-1, the condenser 1-2 provides heat Q2 to the heat absorber 2-2, the steam turbine 3 drives the generator 6 to do work W, and the residual heat Q3 passes through the condenser 4 to the heat sink 4. The cooling tower 9 dissipates heat.

Among them, the water pump 11 at the water outlet of the purifying water supplement 8 is a water supplement pump to supplement the lost water to the system. The water pump 12 at the water outlet of the low temperature water storage 5 is a high pressure pump to provide sufficient delivery pressure. A vacuum pump 15 is also provided at the condenser storage 10 for evacuation to prevent air from leaking into the negative pressure system.

A flow control valve 21 is provided at the water inlet of the heat absorber 2-1, the sensor 31 detects the output temperature of the water outlet of the heat absorber 2-1, and the flow control valve 21 controls the amount of water inflow according to the output temperature. Similarly, a flow control valve 22 is provided at the water inlet of the heat absorber 2-2, the sensor 32 detects the output temperature of the water outlet of the heat absorber 2-2, and the flow control valve 22 controls the amount of water intake according to the output temperature. The high temperature and high pressure water storage heat storage device 7 is also provided with a sensor to detect the water temperature, water level and pressure in the high temperature and high pressure water storage heat storage device 7 .

The condenser 1 provides heat Q1 to the heat absorber 2 , the steam turbine 3 drives the generator 6 to do work W, and the residual heat Q2 after the work is radiated to the cooling tower 9 through the condenser 4 . In the case of no heat loss, Q1=W+Q2.

The purified water in the water purification device 8 is treated pure water, and the high temperature and high pressure water storage and heat storage device is made of metal materials such as steel, with a pressure resistance above 25MPa and a high temperature resistance above 370°C.

When it is used for the first time, pure water is delivered from the water purification device 8 to the low temperature water storage 5 . During subsequent use, when there is consumption of pure water, the water purification device 8 replenishes the low temperature water storage 5 with pure water.

As shown in Figures 3 and 4, when the system has enough heat stored and the light is good, the energy storage power generation system of the present invention can enter the direct work mode. In this case, the circulation of the working medium does not pass through the high temperature and high pressure water storage heat storage 7, but directly enters the steam turbine 3 to do work after the heat absorber 2 absorbs enough heat.

The specific circulation method is as follows: the low-temperature water in the low-temperature water storage 5 is sent to the heat absorber 2-1. The solar heat is sent to the low temperature water in the heat absorber 2 through the condenser lens 1-1 to generate high temperature water. The steam generated by the high-temperature water enters the balance steam storage tank 40 to prevent the steam from impacting the subsequent equipment. The steam in the balance steam storage tank 40 enters the steam turbine 3 and pushes the generator 6 to do work. The water after work enters into the condenser 4 and releases the remaining heat through the cooling tower 9 . The low-temperature water after heat release enters the condensed water storage from the condenser 4, and then returns to the low-temperature water storage 5 to complete the power cycle.

As shown in Figures 5 and 6, when the system needs to store heat and the illumination is good, the energy storage power generation system of the present invention can enter the energy storage mode. In this case, the high-temperature water that has absorbed enough heat in the heat sink 2-2 enters the high-temperature and high-pressure water storage heat storage 7 for heat storage. The specific method of the energy storage cycle is as follows: the heat absorber 2-2 absorbs heat through the condenser lens 1-2, and heats the water in the heat absorber 2-2 into high temperature water. The high temperature water enters the high temperature and high pressure water storage and heat storage device 7 from the lower part of the high temperature and high pressure water storage and heat storage device 7 to store energy. The low-temperature water in the high-temperature and high-pressure water storage heat storage device 7 enters the heat sink 2-2 to be heated to complete the energy storage cycle.

As shown in Figures 7 and 8, in the case of insufficient sunlight such as night and rainy days, the energy storage power generation system of the present invention can enter the energy discharge and work mode, and the high temperature medium previously stored in the high temperature and high pressure water storage heat storage device 7 can pass through. The generator 6 is driven by the steam turbine 3 to work. In this case, the specific circulation method is: open the valve 26, the high-temperature water stored in the high-temperature and high-pressure water storage and heat storage device 7 enters the steam turbine from the upper part of the high-temperature and high-pressure water storage and heat storage device 7 through the balance steam storage tank 40 in the form of steam. In 3, steam is generated to drive the generator 6 to work. The low-temperature water generated after operation enters the low-temperature water storage 5 through the condenser 4 and the condensed water storage. The low-temperature water in the low-temperature water storage 5 returns to the high-temperature and high-pressure water storage heat storage 7 to start the next cycle.

Through the construction of the above-mentioned system structure and the setting of various circulation modes, the energy storage power generation system of the present invention can be used not only under the conditions of good illumination, but also under the conditions of poor illumination at night, cloudy and rainy days. By using the working medium in the heat sink directly for the steam turbine to do work, the heat exchange process between the heat sink medium and the working medium is avoided, the energy loss in the process is reduced, and the utilization efficiency of solar energy is improved.

It should be noted that, in the above-mentioned embodiments of the present application, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

The above are only the preferred embodiments of the present application. It should be pointed out that for those skilled in the art, without departing from the principles of the present application, several improvements and modifications can also be made. It should be regarded as the protection scope of this application.

Claims (7)

1. A high-temperature water heat storage photothermal power generation system, characterized in that, comprising a concentrating heat collecting unit, a heat storage unit and a power generating unit; The light concentrating and heat collecting unit includes a tracking condenser composed of a condenser lens and a tracking system, at least one heat absorber and a low temperature water storage, and each heat absorber has at least one corresponding tracking condenser to provide the concentrated solar light and heat, and the low temperature water storage. The outlets are respectively connected with the inlets of the corresponding heat sinks; The heat storage unit includes a plurality of high temperature and high pressure water storage heat storage devices; the outlet of the heat absorber is communicated with the bottom end inlet of the high temperature and high pressure water storage heat storage device; the top outlet of the high temperature and high pressure water storage heat storage device is connected to the high pressure steam turbine. The inlet of the high temperature and high pressure water storage heat storage device is communicated with the outlet of the low temperature water storage device; The power generation unit includes a steam turbine, a generator, a condenser, a cooling tower, and a balance steam storage tank. The inlet of the steam turbine is connected to the corresponding heat absorber outlet through the balance steam storage tank; the steam turbine outlet is connected to the generator to do work, and is connected to the condenser and the condenser. The cooling tower is communicated with each other, and the other end of the balance steam storage tank is communicated with the high temperature and high pressure water storage heat storage device. 2 . The high-temperature heat storage photothermal power generation system according to claim 1 , wherein the high-temperature and high-pressure water storage and heat storage device is made of metal material, with a pressure resistance of 25 MPa and a high temperature resistance of 370 degrees Celsius. 3 . 3. The high-temperature water heat storage photothermal power generation system according to claim 1, wherein the condensed water storage is also provided with a vacuum pump for evacuating, and the condenser is provided with a cooling capacity for the condenser. Cooling Tower. 4. The high-temperature water thermal storage photothermal power generation system according to claim 1, wherein the purified pure water is replenished to the low-temperature water storage from the purifying water supply device through a water pump and a valve; The flow valve enters the heat absorber, and the outlet of the heat absorber is provided with a sensor, and the sensor controls the flow rate of the flow control valve; in the heat absorber, the water medium is heated into high-temperature water, steam or superheated steam. 5. The high-temperature water heat storage CSP system according to claim 1, wherein the water medium is heated in the heat absorber to generate steam to directly generate electricity, and enters the balance steam storage tank and the balance steam storage tank through a valve. After the steam turbine, the steam turbine drives the generator to generate electricity. The low-temperature steam after power generation is condensed into water in the condenser, and then enters the condensed water storage, and is transported to the low-temperature water storage through the water pump and valve to complete a direct power generation cycle. 6 . The high-temperature water heat storage photothermal power generation system according to claim 1 , wherein, during heat storage, the water medium is heated into steam or high-temperature water in the heat absorber, and the steam or high-temperature water is removed from the heat sink. 7 . The heat absorber enters the heat storage unit for thermal energy storage; the water in the high temperature and high pressure water storage heat storage unit of the heat storage unit can also be sent to the heat absorber again through the water pump and valve for heating and transported back The high temperature and high pressure heat storage device is used until the high temperature and high pressure water reaches the critical saturation state or control requirements. 7 . The high temperature water heat storage photothermal power generation system according to claim 1 , wherein the high temperature and high pressure water storage heat storage device is connected to one end of the balance steam storage tank, and the high temperature and high pressure water storage heat storage device has a high temperature The high-temperature steam generated by the water enters the steam turbine after passing through the balance steam storage tank, and drives the steam turbine to generate electricity.

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