ES2960658A1 - Salt melting system for solar thermal power station based on molten salt solar heat collection field - Google Patents

Abstract

A salt melting system for a solar thermal power station based on a molten salt solar heat collection field (2), the system comprising a salt melting furnace (1), the molten salt solar heat collection field (2), and a molten salt storage tank (3), wherein the salt melting furnace (1) is in communication with an inlet of the molten salt solar heat collection field (2) by means of a molten salt pipeline (4); the salt melting furnace (1) is in communication with the molten salt storage tank (3) by means of a conveying pump (5); and an outlet of the molten salt solar heat collection field (2) is in communication with the salt melting furnace (1) by means of a first pipeline (11).

Description

DESCRIPTION

Salt fusion system of the solar thermal power plant based on the field of fused salt solar collectors

Technical field

The present invention relates to a fused salt fusion system of a solar thermal power plant, and belongs to the technical field of salt fusion system.

Basic technology

Before introducing the fused salt into the solar thermal power plant, it is mainly supplied in solid form (because the fused salt is solid at room temperature), and the use of solid form supply is convenient for the transportation and storage of fused salt. And when the fused salt has to be put into the solar thermal power plant for heat storage, it is necessary to convert a large number of solid fused salt into high temperature liquid fused salt, the way is to realize the initial melting for the fused salt, the Initial melting of fused salt is a critical process of fused salt heat storage system of solar thermal power plant before entering into commissioning, through this process the solid fused salt becomes high temperature liquid fused salt in the system to start the cycle, and maintains the liquid state throughout the useful life of the solar thermal plant.

In existing solar thermal power plants, there are two solutions to realize salt fusion, one of which is to use electric heater for initial salt fusion, and then use the fused salt circulation pump to pump the low temperature liquid fused salt to the natural gas salt melting furnace, and then through the high temperature smoke produced by the combustion of natural gas, the salt fused in the coils in the melting furnace is heated to a high temperature state, and then is transported back to the fused salt tank. Sodium nitrate and potassium nitrate (solid fused salt) are added proportionally into the fused salt tank, and when the temperature of fused salt in the fused salt tank meets the requirement, the fused salt is transported to the salt tank fused through another fused salt transport pump; The second is that after crushing and mixing the sodium nitrate and potassium nitrate according to the proportion, they directly enter the natural gas melting furnace, and in the furnace chamber it is set with a heat exchanger coil , which contains high temperature smoke, and the flow direction is opposite to the stirring direction of the liquid in the furnace, and the liquid fused salt is overflowed into the buffer tank through the overflow pipe, and then pumped into the buffer tank. fused salt from the buffer tank. The above two traditional methods use the burning natural gas smoke as a heat source to heat the solid fused salt particles, and in the fusion process a large amount of natural gas needs to be consumed. Due to the technical limitations of the natural gas furnace itself and for safety reasons, the melting speed is about 30-40 t/h. After the merge process is complete, the associated merge equipment is no longer useful in this project and can only be used to re-merge in the next project or left as waste.

In addition to the above, the traditional fusion method has the following disadvantages:

1. The melting furnace system built using natural gas heating to achieve fusion has high cost, and after achieving fusion once, the fused salt is introduced into the solar thermal system for use, and there is no need to melt again, so the associated equipment of the natural gas melting furnace system is not used reasonably;

2. When the natural gas melting furnace system is used to achieve fusion, it is necessary to burn natural gas, and in the large-scale fused salt solar thermal power plant project with several tens of thousands of tons, the cost of gas natural is higher;

3. The amount of carbon dioxide emitted by the combustion of natural gas in the natural gas melting furnace system is large, which is polluting the environment to a certain extent;

4. The natural gas melting furnace system has limited heating capacity, and the melting speed is slow and the melting cycle is long in the large-scale solar thermal power plant fused salt project with tens of thousands of tons of fused salt.

Based on the above, it is of great importance to carry out research work on the fusion technical solution to shorten the fusion cycle, reduce the fusion cost, improve the fusion speed and quality, and ensure that both the generation of solar thermal energy and fusion can be carried out.

Content of the invention

The present invention aims to shorten the melting cycle and reduce the melting cost. A brief overview of the invention is provided below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify key or important parts of the invention, nor is it intended to limit the scope of the invention.

Technical solution of the present invention:

A fusion system of the solar thermal power plant based on a field of fused salt solar collectors, comprising the fusion furnace, the field of fused salt solar collectors and the fused salt storage tank, said fusion furnace being connected to an inlet of the fused salt solar collector field through a fused salt pipe, the melting furnace connected to the fused salt storage tank through a transport pump, and the outlet of the fused salt solar collector field It is connected to the melting furnace through a first pipe.

Preferred: It further comprises an auxiliary electric heater, the inlet of which is connected to the fused salt pipe, and the auxiliary electric heater is connected to the melting furnace through a second pipe.

Preferred: said first pipe and said second pipe are equipped with a valve and a temperature measuring instrument, respectively.

Preferred: said electrical energy used in said auxiliary electric heater comes from abandoned wind energy, abandoned photovoltaic energy or off-peak energy.

Preferred: a circulation pump is installed in the connection pipe of said melting furnace with the fused salt solar collector field and the auxiliary electric heater.

The present invention has the following beneficial effects:

1. The melting system of the present invention solves the problem that the solid fused salt of the traditional solar thermal power plant is dissolved by the dedicated natural gas melting furnace system, and the dedicated natural gas melting furnace realizes the process melting process, which is limited by the heating capacity of the furnace, the amount of natural gas, etc., so that the melting efficiency is not high, and the entire melting cycle cannot be guaranteed, and the fuel cost fusion is high.

2. The present invention makes use of the solar thermal power generation system to carry out the fusion work, so that the power generation and fusion can be carried out at the same time, and the fusion capacity is much larger than that of the special natural gas melting furnace system;

3. The present invention uses solar thermal fusion during the day when there is sun, and uses electric heating to absorb abandoned energy or off-peak energy for fusion at night when there is no sun, which effectively shortens the cycle of fusion.

4. Compared with the traditional fusion method, the present invention realizes fusion by solar thermal method, and its fusion speed is significantly improved, and the system is simple, easy to operate, with high safety and energy saving and environmentally friendly.

5. Compared with the traditional fusion method, the traditional fusion method is affected by the equipment environment, the equipment itself and the plant environment, and the salt cleanliness is low, while the fusion by salt exchange Solar thermal heat is clean and efficient.

6. Adopting the melting solution of the present invention, the sodium nitrate and potassium nitrate are crushed and transported proportionally to the melting furnace, and after the initial melting using an electric heater, a circulation pump is used fused salt to pump the low temperature fused liquid salt in the melting furnace to a fused salt solar collector field, which absorbs high temperature solar energy through the fused salt solar collector field, heats the fused salt to high temperature, then transports it back to the melting furnace, and the high temperature liquid salt is mixed with the room temperature solid salt. The high temperature liquid salt is mixed with the solid fused salt to form the low temperature liquid fused salt above 270°C, and then it is transported and stored in the fused salt storage tank.

The melting speed in the solar thermal fusion system is more than 210 t/h, which is 5 to 7 times higher than that of traditional fusion. Solar thermal fusion uses solar energy as a source of the heat necessary for fusion without fossil fuels, which is clean and environmentally friendly. Save construction costs by using the original heat exchange equipment of the solar thermal power plant. After the fusion is completed, the associated charging system can be disassembled and recycled for reuse, and the melting furnace and electric heater can be directly converted into a high temperature energy storage system, which can be used to absorb wind energy and abandoned photovoltaics and achieve energy storage.

7. With the melting system of the present invention, the salt melting speed is more than 210 tons/hour, which is five times faster than the traditional salt melting speed, and can be more than 4,000 tons per day, which is more than four times the previous world record for melting salt in a single day, and it takes only two and a half weeks to melt 70,000 tons of salt continuously, which is two months faster than melting traditional salt, and achieves the power generation of the storage system in advance, and saves 10 million yuan of fossil fuels used in salt melting and 20% of the investment in equipment compared with that of the salt melting system. traditional salt.

illustration in figures

Figure 1 shows a diagram of the fusion system of a solar thermal power plant based on a field of fused salt solar collectors;

Figure 2 is a diagram of the fusion system of the specific implementation II;

Figure 3 is a schematic diagram of the relationship between the salt melting amount and the salt melting cycle of the traditional melting method and the melting method of the present invention;

In the figure, 1 - salt melting furnace, 2 - fused salt solar collector field, 3 - fused salt storage tank, 4 - fused salt pipe, 5 - transport pump, 8

- valve, 9 - temperature measuring instrument, 10 - auxiliary electric heater, 11 - first pipe, 12 - second pipe, and 14 - circulation pump.

specific implementation

In order to make the objects, technical solutions and advantages of the present invention increasingly clear, the invention is described below by means of the specific implementation example illustrated in the attached figures. It should be understood, however, that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily confusing the concepts of the present invention.

Specific implementation I:

Referring to Figure 1, the present implementation provides a solar thermal power plant fusion system based on a fused salt solar collector field, comprising a melting furnace 1, a fused salt solar collector field 2, and a tank of fused salt tank 3, in which said melting furnace 1 is connected to an inlet of the fused salt solar collector field 2 through a fused salt pipe 4, and in which the melting furnace 1 is connected to the fused salt storage tank 3 through a transport pump 5, and in which an outlet of the fused salt solar collector field 2 is connected to the melting furnace 1 through a first pipe 11.

In this implementation, in the melting furnace 1, the solid salt and the high temperature fused salt of 300-440 degrees Celsius are mixed in the melting furnace 1 to form liquid fused salt of medium temperature of 280-340 degrees Celsius, and the formed medium temperature liquid fused salt is entirely sent to the fused salt reservoir tank 3 for storage through the transport pump 5, and the other part is pumped to the fused salt solar collector 2 through the circulation pump, and with the fused salt thermal solar collector field 2 the medium temperature liquid fused salt (280-340°C) is heated and converted into high temperature liquid fused salt (300-440C), and Subsequently, this high-temperature fused salt is transported to the melting furnace 1 to achieve melting circulation, and the transportation amount ensures that the solid fused salt newly added to the melting furnace 1 is able to reach a certain temperature and fuse the solid fused salt.

In this implementation, the fused salt solar collector field 2 is used to raise the temperature of the medium temperature fused salt to a high temperature fused salt, and the high temperature fused salt temperature is used to perform the work of fusion, in order to realize both power generation and fusion, and the fusion capacity is much larger than that of the melting furnace system;

In this implementation, the field of fused salt solar collectors 2 includes channel-type, tower-type fused salt collectors, and the like.

The melting system of the present implementation solves the problem that the solid fused salt of the traditional solar thermal power plant is dissolved through a dedicated natural gas melting furnace system, and the traditional dedicated natural gas melting furnace realizes the melting process, which is limited by the heating capacity of the furnace, natural gas consumption and other factors, the complete melting cycle is not guaranteed, and the melting cost is still high.

In this implementation, using this implementation of the fusion system, its fusion speed is more than 210 tons per hour, five times faster than the traditional fusion speed, it can be more than 4,000 tons per day, more than four times the record world's largest single-day meltdown, continuous melting of 70,000 tons of salt in just two and a half weeks, two months faster than traditional melting, can be done in advance of heat island storage to generate electricity, to save fossil fuels of ten million yuan, equipment investment also saves 20% compared with the traditional fusion system, and the specific comparison is shown in the figure:

Table 1: Comparison between the fusion system of the solar thermal power plant and the traditional fusion system

It should be noted that in solar power generation projects, traditional international fusion systems currently use natural gas melting furnaces, which use the combustion smoke of natural gas to provide heat to fuse the solid fused salt into a liquid state.

When a solar energy project requires fusion, the traditional way is to purchase a natural gas melting furnace, and then use the combustion smoke of natural gas to provide heat to fuse the solid fused salt into a liquid state;

Different from the traditional way of fusion, in this implementation, the original equipment of the solar power plant is used to carry out the fusion operation, for example, the fused salt solar collector 2 used in this implementation are all Existing power plant equipment, which is originally used for the purpose of solar power generation, and in this implementation, is used to form a fusion system according to the form of cooperation and connection of various technical characteristics of this implementation, and the system is used for fusion implementation, which saves the acquisition and construction cost of the natural gas melting furnace, reduces the carbon dioxide emission of the melting process, and improves the melting speed and the fusion cycle using existing equipment to perform fusion (as shown in Fig. 3);

It should be noted that: the heat storage medium used in the solar thermal power plant project is high-temperature fused salt, and in the case of the Urat Zhongqi 100MW tank-type conductive thermal oil solar thermal power generation project, for For example, the power plant is equipped with a high-temperature fused salt heat storage system, and the high-temperature fused salt used in the system is a mixture of potassium nitrate in a mass fraction of 40% and sodium nitrate in a mass fraction of 60%. Before commissioning of the fused salt storage system, the solid fused salt must be fused and injected into the cold salt tank, and this step (melting) plays a critical role in the smooth commissioning of the storage system heat, as well as in official commissioning. At present, the international traditional melting system adopts natural gas melting furnace, which uses the heat provided by natural gas combustion smoke to fuse the solid fused salt and convert it into liquid state. This traditional fusion system not only has a low fusion rate, which makes it impossible to put the heat storage system into operation in a short period of time, but also requires the consumption of a large amount of fossil fuels, which It is contrary to the "double carbon" commitment. Due to the high melting temperature of the fused salt and the technical difficulties of the fusion system, a new type of high-speed, low-carbon fusion technology has hardly been explored in practice at home and abroad.

The use of the fusion system of the present implementation mode can ensure that both solar thermal power generation and fusion are achieved, and it is of great importance that it is used for the realization of fusion in the solar thermal power generation project.

Specific implementation II:

In combination with Fig. 2, a solar thermal power plant fusion system based on a fused salt solar collector field, comprising a melting furnace 1, a fused salt solar collector field 2, and a storage tank of fused salt 3, said melting furnace 1 being connected to an inlet of the fused salt solar collector field 2 through a fused salt pipe 4, the melting furnace 1 being connected to the fused salt storage tank 3 through of a transport pump 5, and the outlet of the fused salt solar collector field 2 being connected to the melting furnace 1 through a first pipe 11, and also comprising an auxiliary electric heater 10, the input of the auxiliary electric heater being 10 connected to the fused salt pipe 4, and the auxiliary electric heater 10 being connected to the melting furnace 1 through the second pipe 12.

In this implementation, in the melting furnace 1, the solid salt and the high temperature fused salt of 300-440 degrees Celsius are mixed in the melting furnace 1 to form liquid fused salt of medium temperature of 280-340 degrees Celsius, and the formed medium temperature liquid fused salt is sent entirely to the fused salt storage tank 3 for storage through the transport pump 5, and the other part is pumped to the fused salt solar collector 2 and/or to the auxiliary electric heater 10 through the circulation pump, and in the fused salt thermal solar collector field 2, or the auxiliary electric heater 10, the medium temperature liquid fused salt (280-340°C) is heated and is converted into high temperature liquid fused salt (300-440C), and subsequently, this high temperature fused salt is transported to melting furnace 1 to achieve melt circulation, and the transportation amount ensures that the newly solid fused salt added to the melting furnace 1 is capable of reaching a certain temperature and fusing the solid fused salt.

Specific implementation III:

Referring to Figures 1 and 2, and on the basis of specific implementation I and specific implementation II, said first pipe 11 and second pipe 12 are respectively equipped with a valve 8 and a temperature measuring instrument 9, the valve 8 being used to control the switching of the pipeline, and the temperature measuring instrument 8 to measure the temperature of the fluid in the pipeline. Through the interaction of information from the valve 8 and the temperature measuring instrument 9, the opening and closing of the fused salt in the first pipe 11 and the second pipe 12 are controlled in real time to ensure that the work of Fusion takes place without problems.

Specific implementation IV:

On the basis of specific implementation II, the electrical energy used in said auxiliary electric heater 10 is derived from low-cost electricity, such as abandoned wind energy, abandoned solar thermal energy and off-peak energy, the cost of which is less than cost of electrical energy provided by traditional power plants.

Specific implementation V:

In relation to Figures 1 and 2, and in relation to the specific implementation I, a circulation pump 14 is mounted in the connection pipe of said melting furnace 1 with the field of fused salt solar collectors 13 and the electric heater auxiliary 10. A circulation pump 14 is used to pump the low temperature fused liquid salt from the melting furnace to the fused salt solar collector field.

It should be noted that the terms used herein are intended only to describe specific implementations and are not intended to limit exemplary implementations in accordance with the present application. As used herein, the singular form is also intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprising" and/or "including" are used herein specification, indicate the presence of features, steps, operations, devices, components and/or combinations thereof.

The relative arrangement, numerical expressions and values of the components and steps set forth in these implementations do not limit the scope of the present invention unless otherwise specified. At the same time, it should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn in actual proportional relationship for ease of description. Techniques, methods and apparatus known to a person of ordinary skill in the relevant field may not be discussed in detail, but where applicable, such techniques, methods and apparatus should be considered part of the authorized specification. In all examples illustrated and discussed here, any specific values should be interpreted as merely exemplary and not limitations. Thus, other examples of exemplary implementations may have different values. It should be noted that: similar labels and letters denote similar elements in subsequent accompanying figures, and therefore, once an element is defined in an accompanying figure, no further discussion of it in subsequent accompanying figures is required.

In the description of the present invention, it should be understood that the orientation or position relationships indicated by these orientation words such as "front, back, up, down, left, right", "side, vertical, vertical, horizontal" and "up, down" indicate an orientation or positional relationship that is generally based on the orientation or position relationships shown in the accompanying figures, and are intended only to facilitate the description of the present invention and simplify the description, and, in the absence Notwithstanding any indication to the contrary, these words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operate in a specific orientation, and therefore should not be construed as limiting the scope protection of the present invention; The words "interior and exterior" refer to interior and exterior in relation to the contours of the components themselves.

For ease of description, space-related terms may be used in this document, such as "on top of .....", "above .....", "on the upper surface of ....." , "above", etc., to describe the spatial location of a device or feature in spatial location relationships with other devices or features, as shown in the figures. It should be understood that the space-related terms are intended to encompass different orientations in use or operation, in addition to the orientation of the device depicted in the figures. For example, if the devices in the accompanying figures are inverted, a device described as "above another device or structure" or "on top of another device or structure" would later be placed as "below another device or structure" or "below of another device or structure". Thus, the exemplary term "above..." may include "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations) and the space-related descriptions used here are explained accordingly.

It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and in the accompanying figures described above are used to distinguish similar objects and need not be used to describe a particular order or sequence. It should be understood that data so used may be exchanged, where applicable, so that the implementations of the present application described herein may be implemented in an order other than those illustrated or described herein.

It should be noted that in the above implementations, as long as non-contradictory technical solutions are susceptible to permutations and combinations, technical personnel in the field are able to exhaust all possibilities based on mathematical knowledge of permutations and combinations, Therefore, the present invention will not illustrate each and every permutation and combination, but it should be understood that the permutations and combinations have been disclosed by the present invention.

This implementation is only an exemplary description of the patent, and does not limit its scope of protection, the technical personnel in the field can also be changed at a partial level, as long as it does not exceed the spirit of the patent, they are within the scope of protection of the patent.

Claims (5)

1. A solar thermal power plant salt fusion system based on a field of fused salt solar collectors, characterized in that: it comprises a salt fusion furnace (1), a field of fused salt solar collectors (2), and a fused salt storage tank 3, in which said melting furnace (1) is connected to an inlet of the fused salt solar collector field (2) through a fused salt pipe (4), and in which The melting furnace (1) is connected to the fused salt storage tank (3) through a transport pump (5), and in which an outlet of the fused salt solar collector field (2) is connected to the melting furnace (1) through a first pipe (11). Claim 2 2. A solar thermal power plant salt fusion system based on a field of fused salt solar collectors according to claim 1, characterized in that: it further comprises an auxiliary electric heater (10), the input of the auxiliary electric heater (10) is connected to the melting pipe 4, and the auxiliary electric heater (10) is connected to the melting furnace (1) through the second pipe (12). 3. A thermal solar power plant salt fusion system based on a field of fused salt solar collectors according to claim 2, characterized in that: said first pipe (11) and said second pipe (12) are provided with a valve (8) and a temperature measuring instrument (9) respectively. 4. A salt fusion system for a solar thermal power plant based on a field of fused salt solar collectors according to claim 2, characterized in that: the electrical energy used in said auxiliary electric heater (10) comes from abandoned wind energy, the energy abandoned photovoltaics or off-peak energy. 5. A thermal solar power plant salt fusion system based on a field of fused salt solar collectors according to claim 2, characterized in that: said fusion oven (1) is provided with a circulation pump (14) in the connection to the fused salt solar collector field (13) and the auxiliary electric heater (10).