CN210119022U - Tower type solar thermal power generation system based on cavity column type heat collector - Google Patents

Abstract

The utility model provides a tower solar thermal power generation system based on cavity post formula heat collector can effectively reduce the front and back difference in temperature of heat-absorbing pipe to plain noodles and shady plain noodles. The outer heat absorption tube group is provided with an outer heat absorption tube group opening, the inner heat absorption tube group is provided with an inner heat absorption tube group opening, the outer heat absorption tube group opening and the inner heat absorption tube group opening are combined to form a fan-shaped opening, and the fan-shaped opening faces to a field area close to the sun heliostat; gaps are reserved between the outer heat absorption pipe and the inner heat absorption pipe, between two adjacent pipes in the outer heat absorption pipe and between two adjacent pipes in the inner heat absorption pipe; the selective absorption coating I is coated on the half circumference of the far-sun side of the external heat absorption pipe, the selective absorption coating II is coated on the half circumference of the near-sun side of the external heat absorption pipe, the selective absorption coating III is coated on the half circumference of the far-sun side of the internal heat absorption pipe, and the selective absorption coating IV is coated on the half circumference of the near-sun side of the internal heat absorption pipe.

Description

Tower type solar thermal power generation system based on cavity column type heat collector

Technical Field

The utility model relates to a tower solar thermal power generation system based on cavity post formula heat collector.

Background

Solar power generation has been a research hotspot in countries around the world for over the last decade, with built and established installed capacities remaining as high as 30% per year. The typical tower type solar thermal power generation technology has higher power generation efficiency and is developed rapidly because the used pipeline is short, the condensation ratio is high, and high-parameter steam can be generated.

The theoretical light concentration ratio of the tower type power generation system exceeds 1000, the light facing surface of the heat absorption pipe needs to bear higher heat load, and the backlight surface is usually a heat insulation structure. Therefore, the heat absorption pipe receiving light at one side is easy to form local overheating, the front side and the rear side have large temperature difference, and in a region with high heat flow density, the front temperature difference and the rear temperature difference of the heat absorption pipe can exceed 200 ℃, so that the heat absorption pipe is seriously deformed, and under the constraint of a heat absorber structure, the heat absorber pipe needs to bear high stress, and the service life of the heat absorption pipe is shortened. Therefore, one of the main problems in the operation of the heat absorber is how to obtain a more uniform heat flow distribution and reduce the front-back temperature difference between the light facing surface and the backlight surface of the heat absorbing pipe.

The application number 201510095504.0 discloses a solar tower-type heat absorber with a double-tube structure, which comprises a heat absorption module, wherein the heat absorption module comprises an outer ring heat absorption tube, an inner ring heat absorption tube and sealing fins; certain gaps are reserved between two adjacent tubes of the outer ring heat absorption tube and between the outer ring heat absorption tube and the inner ring heat absorption tube, and the inner ring heat absorption tubes are connected into a group through a close-packed or fin structure to play a role in sealing and transferring heat to sunlight received by the solar tower type heat absorber with the double-row structure. A certain gap is reserved between two adjacent tubes of the outer ring heat absorption tube, so that part of sunlight can irradiate on the inner ring heat absorption tube through the gap. The rear half part of the outer ring heat absorption pipe is heated by a part of sunlight received by the inner ring heat absorption pipe in a reflection or heat radiation mode, so that the front-back temperature difference of the heat absorption pipe wall can be effectively reduced, and the purposes of reducing the thermal stress and prolonging the service life of the heat absorber are achieved. But it has the following disadvantages: the outer ring heat absorption tube and the inner ring heat absorption tube only have direct sunlight towards the half circumference of the mirror field, the half circumference which does not face the mirror field only has reflected sunlight, and the backlight surface of the inner ring heat absorption tube is not heated, so that the local overheating problem of the heat absorption tube is restrained to a certain degree, but the front-back temperature difference between the backlight surface and the backlight surface of the heat absorption tube still cannot reach an ideal degree.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome the above-mentioned not enough that exists among the prior art, and provide a tower solar thermal power generation system based on cavity post heat collector that structural design is reasonable, can effectively reduce the front and back difference in temperature of heat absorption pipe to plain noodles and shady plain noodles.

The utility model provides a technical scheme that above-mentioned problem adopted is: a tower type solar thermal power generation system based on a cavity column type heat collector comprises a heat collector and a heliostat field; the heat collector comprises an external heat absorption tube set and an internal heat absorption tube set, wherein the external heat absorption tube set is composed of external heat absorption tubes, the internal heat absorption tube set is composed of internal heat absorption tubes, and the external heat absorption tubes are arranged outside the internal heat absorption tubes; the heliostat field is divided into a near-sun heliostat field and a far-sun heliostat field; the method is characterized in that: the outer heat absorption tube group is provided with an outer heat absorption tube group opening, the inner heat absorption tube group is provided with an inner heat absorption tube group opening, the outer heat absorption tube group opening and the inner heat absorption tube group opening are combined to form a fan-shaped opening, and the fan-shaped opening faces to a field area close to the sun heliostat; gaps are reserved between the outer heat absorption pipe and the inner heat absorption pipe, between two adjacent pipes in the outer heat absorption pipe and between two adjacent pipes in the inner heat absorption pipe; the heat collector also comprises a first selective absorption coating, a second selective absorption coating, a third selective absorption coating and a fourth selective absorption coating; the selective absorption coating I is coated on the half circumference of the far-sun side of the external heat absorption pipe, the selective absorption coating II is coated on the half circumference of the near-sun side of the external heat absorption pipe, the selective absorption coating III is coated on the half circumference of the far-sun side of the internal heat absorption pipe, and the selective absorption coating IV is coated on the half circumference of the near-sun side of the internal heat absorption pipe.

Nearly sun heliostat field area and far sun heliostat field area divide into two fan-shaped regions with whole heliostat field.

Outside heat absorption tube bank and inside heat absorption tube bank set up with one heart.

Outside heat-absorbing pipe constitute steam evaporator, inside heat-absorbing pipe constitute steam superheater.

Fan-shaped open-ended angle and fan-shaped regional angle in nearly sun heliostat field the same.

Outside heat absorption pipe and inside heat absorption pipe be the staggered distribution.

The third selective absorption coating of the utility model has lower absorption rate than the fourth selective absorption coating.

The absorption rate of the selective absorption coating I is lower than that of the selective absorption coating II.

Compared with the prior art, the utility model, have following advantage and effect:

(1) the fan-shaped opening enables the inner heat absorbing pipe and the outer heat absorbing pipe not to have complete backlight surfaces, direct sunlight is arranged on the whole circumference of the inner heat absorbing pipe and the whole circumference of the outer heat absorbing pipe, heat flow distribution on the circumferential surface of the heat absorbing pipe is more uniform, the front and back temperature difference of the light facing surface and the backlight surface of the heat absorbing pipe can be effectively reduced, the heat absorbing pipe achieves a relatively ideal degree, the selection requirement on heat absorbing pipe materials is reduced, and initial investment cost of the heat collector is further reduced.

(2) The inner heat absorption tubes and the outer heat absorption tubes correspond to heliostat fields in different areas, and difficulty of a heliostat field tracking control system is effectively reduced.

(3) The inner heat absorption pipe and the outer heat absorption pipe can mutually absorb partial heat dissipation loss of the other side, and the heat efficiency of the heat collector is improved.

Drawings

Fig. 1 is a schematic structural diagram of a heat collection module according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of a heliostat field in accordance with an embodiment of the invention.

Fig. 3 is a schematic diagram of the heat receiving of the outer heat absorbing pipe and the inner heat absorbing pipe of the embodiment of the present invention.

Fig. 4 is a schematic structural diagram of an external heat absorbing pipe according to an embodiment of the present invention.

Fig. 5 is a schematic structural view of an inner heat absorbing pipe according to an embodiment of the present invention.

Detailed Description

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

Referring to fig. 1-5, embodiments of the present invention include a heat collector and a heliostat field.

The heliostat field is divided into a near-sun heliostat field 4 and a far-sun heliostat field 5, the cosine loss of the heliostat of the near-sun heliostat field 4 is larger than that of the heliostat of the far-sun heliostat field 5, so that heliostats can be arranged in the far-sun heliostat field 5 more, and the reflection efficiency of the whole heliostat is improved. The near-sun heliostat field 4 and the far-sun heliostat field 5 divide the entire heliostat field into two sectorial regions, the angle of the sectorial region formed by the near-sun heliostat field 4 being θ 2, and the angle of the sectorial region formed by the far-sun heliostat field 5 being thus 360 ° - θ 2.

The heat collector comprises an external heat absorption pipe set, an internal heat absorption pipe set, a first selective absorption coating 11, a second selective absorption coating 12, a third selective absorption coating 21 and a fourth selective absorption coating 22. The external heat absorption tube set is composed of external heat absorption tubes 1, and the internal heat absorption tube set is composed of internal heat absorption tubes 2.

The outer heat absorption pipes 1 are arranged outside the inner heat absorption pipes 2, and the outer heat absorption pipes 1 and the inner heat absorption pipes 2 are distributed in a staggered mode.

The outer heat absorption tube set and the inner heat absorption tube set are concentrically arranged. The external heat absorption tube set is a cavity structure which is formed by the internal heat absorption tubes 2 while the external surface light-receiving heat collector absorbs solar energy, so that the radiant heat loss of the internal and external heat absorption tubes can be absorbed mutually, and the heat efficiency of the heat collector is improved; the internal heat absorption tube set is similar to a cavity type heat collector. The structure forms a novel cavity column type heat collector, the cavity column type heat collector has the advantages that the light-receiving type heat collector on the outer surface of the cylindrical surface fully utilizes the land area around the heat collecting tower, and the cavity column type heat collector has the advantages of small radiation and convection heat dissipation losses, so that the heat efficiency of the whole heat collector can be obviously improved. The outer heat absorption tube group is provided with an outer heat absorption tube group opening, the inner heat absorption tube group is provided with an inner heat absorption tube group opening, the outer heat absorption tube group opening and the inner heat absorption tube group opening are combined to form a fan-shaped opening 3, and the angle of the fan-shaped opening 3 is theta 1.

Gaps are reserved between the outer heat absorption tube 1 and the inner heat absorption tube 2, between two adjacent tubes in the outer heat absorption tube 1 and between two adjacent tubes in the inner heat absorption tube 2.

When water is adopted as a heat transfer working medium, the external heat absorption pipe 1 forms a steam evaporator for preheating and evaporating heating of low-temperature water supply, and the internal heat absorption pipe 2 forms a steam superheater for converting saturated steam into superheated steam. The working medium evaporation section and the overheating section are independently arranged, so that the whole heat absorption system is simpler, more economical and safer; meanwhile, solar radiation heat received by the external heat absorption tube 1 and the internal heat absorption tube 2 can be distributed by adjusting the angle theta 1 of the fan-shaped opening 3, and hydrodynamic stability of heat exchange of working media in the heat collector is guaranteed. It is easy to know that the heating heat required by external preheating and evaporative heating is far greater than the overheating heat, so that the sector opening 3 faces the near-sun heliostat field 4, the far-sun heliostat field 5 is matched with the external heat absorbing pipe 1, and the near-sun heliostat field 4 is matched with the internal heat absorbing pipe 2. The external heat absorbing pipes 1 and the internal heat absorbing pipes 2 correspond to heliostat fields in different areas, the difficulty of a heliostat field tracking control system can be effectively reduced, meanwhile, the solar radiation heat received by the external heat absorbing pipes 1 and the internal heat absorbing pipes 2 can be distributed by adjusting the angle theta 2 of the sector area of the near-sun heliostat field 4, and the hydrodynamic stability of working medium heat exchange in the heat collector is further enhanced. The angle theta 1 of the fan-shaped opening 3 is the same as the angle theta 2 of the fan-shaped area of the field 4 of the near-sun heliostat, so that the efficiency of absorbing heat energy is improved. The angle theta 1 of the sector opening 3 and the angle theta 2 of the sector area of the heliostat field area 4 close to the sun can be synchronously adjusted, so that the flexibility and the safety of the whole heat exchange system are enhanced.

The selective absorption coating I11 is coated on the half circumference of the far-sun side of the outer heat absorption pipe 1, the selective absorption coating II 12 is coated on the half circumference of the near-sun side of the outer heat absorption pipe 1, the selective absorption coating III 21 is coated on the half circumference of the far-sun side of the inner heat absorption pipe 2, and the selective absorption coating IV 22 is coated on the half circumference of the near-sun side of the inner heat absorption pipe 2.

The absorptivity of the selective absorption coating I11 is different from that of the selective absorption coating II 12, and the absorptivity of the selective absorption coating III 21 is different from that of the selective absorption coating IV 22. The half circumference of the inner heat absorption pipe 2 close to the sun side is provided with a fan-shaped opening 3, the cosine loss of a heliostat close to a heliostat field 4 is larger than that of a heliostat far away from the heliostat field 5, and the reflected light of the heliostat close to the sun side is less, so that the selective absorption coating four 22 can be set to be high in absorption rate, and the absorption rate can be set to be 0.9; the cosine loss of the mirror field 5 of the far-sun heliostat field is small, the mirror field is large, the absorptivity of the selective absorption coating III 21 on the half circumference of the far-sun side of the inner heat absorption pipe 2 is lower than that of the selective absorption coating IV 22 and is set to be 0.6-0.7, so that the circumferential heat flow distribution uniformity of the inner heat absorption pipe 2 is increased; the unabsorbed sunlight can be absorbed by the outer heat absorbing pipe 1 by reflection in the half circumference near the sun side, and the solar energy is not lost. In order to enable the half circumference of the outer heat absorption pipe 1 close to the sun side to absorb more reflected light, the selective absorption coating layer two 12 can be set to be high in absorption rate, and the absorption rate can be set to be 0.9, so that the circumferential heat uniformity of the outer heat absorption pipe 1 is better; on the half circumference of the outer heat absorption pipe 1 far from the sun side, the mirror field is large, the solar energy is absorbed more, from the view of circumferential uniformity, the absorptivity of the selective absorption coating I11 is lower than that of the selective absorption coating II 12 and is set to be 0.8, although the total solar energy can be lost, the circumferential heat flow distribution uniformity is better.

For the outer heat absorbing pipe 1, the energy received by the half circumference far from the sun side is the solar incident light reflected by the field 5 of the sun heliostat, the energy received by the half circumference near the sun side is three parts, the first part is the solar incident light irradiated by the sunlight reflected by the field 4 of the sun heliostat through the gap between two adjacent pipes in the inner heat absorbing pipe 2, the second part is the reflected light irradiated by the solar incident light reflected by the sun heliostat 5 through the gap between two adjacent pipes in the outer heat absorbing pipe 1 to the half circumference far from the sun side of the inner heat absorbing pipe 2, and the third part is the heat radiation by the half circumference far from the sun side of the inner heat absorbing pipe 2. For the inner heat absorbing pipe 2, the energy received by the half circumference of the far-sun side is three parts, the first part is the incident solar light irradiated by the sunlight reflected by the far-sun heliostat field 5 through the gap between two adjacent pipes in the outer heat absorbing pipe 1, the second part is the reflected solar light irradiated by the incident solar light reflected by the near-sun heliostat field 4 through the gap between two adjacent pipes in the inner heat absorbing pipe 2 to the half circumference of the near-sun side of the outer heat absorbing pipe 1, the third part is the heat radiation of the half circumference of the near-sun side of the outer heat absorbing pipe 1, and the energy received by the half circumference of the near-sun side of the inner heat absorbing pipe 2 is the incident solar light reflected by the near-sun heliostat field 4. The heat receiving conditions of the outer and inner heat absorbing pipes 1 and 2 are shown in table 1.

TABLE 1 heating conditions of the outer absorber tube 1 and the inner absorber tube 2

As can be seen from table 1, the heat received by the semi-circle of the far-sun side and the semi-circle of the near-sun side of the outer heat absorbing pipe 1 and the inner heat absorbing pipe 2 has solar incident light, and there is no absolute backlight surface, and the heat flow distribution uniformity in the circumferential direction of the outer heat absorbing pipe 1 and the inner heat absorbing pipe 2 is improved. The solar radiant quantity irradiated on the external heat absorption tube 1 and the internal heat absorption tube 2 is distributed by optimizing the gap between the external heat absorption tube 1 and the internal heat absorption tube 2, the gap between two adjacent tubes in the external heat absorption tube 1, the gap between two adjacent tubes in the internal heat absorption tube 2, the pipe diameter specifications of the external heat absorption tube 1 and the internal heat absorption tube 2 and other methods, so that the non-uniformity of the heat flow distribution in the circumferential direction of the external heat absorption tube 1 and the internal heat absorption tube 2 is further reduced.

In addition, by adjusting the absorption rate and the reflection rate of the first selective absorption coating 11, the second selective absorption coating 12, the third selective absorption coating 21 and the fourth selective absorption coating 22, the circumferential heat flow distribution uniformity of the outer heat absorption pipe 1 and the inner heat absorption pipe 2 can be further increased, the circumferential temperature difference of the heat absorption pipes can be effectively reduced, the selection requirement of the material of the heat absorption pipes can be further reduced, and the initial investment cost of the heat collector can be reduced. Meanwhile, the external heat absorption pipe 1 and the internal heat absorption pipe 2 mutually absorb the mutual partial heat dissipation loss, so that the heat efficiency of the heat collector can be further improved. According to the actual temperature characteristics of the external heat absorption pipe 1 and the internal heat absorption pipe 2, different pipes can be selected in a targeted manner, and the initial investment cost of the heat collector is further reduced.

In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an example of the structure of the present invention. All the equivalent changes or simple changes made according to the structure, characteristics and principle of the utility model are included in the protection scope of the utility model. Various modifications, additions and substitutions may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims (8)

1. A tower type solar thermal power generation system based on a cavity column type heat collector comprises a heat collector and a heliostat field; the heat collector comprises an external heat absorption tube set and an internal heat absorption tube set, wherein the external heat absorption tube set is composed of external heat absorption tubes, the internal heat absorption tube set is composed of internal heat absorption tubes, and the external heat absorption tubes are arranged outside the internal heat absorption tubes; the heliostat field is divided into a near-sun heliostat field and a far-sun heliostat field; the method is characterized in that: the outer heat absorption tube group is provided with an outer heat absorption tube group opening, the inner heat absorption tube group is provided with an inner heat absorption tube group opening, the outer heat absorption tube group opening and the inner heat absorption tube group opening are combined to form a fan-shaped opening, and the fan-shaped opening faces to a field area close to the sun heliostat; gaps are reserved between the outer heat absorption pipe and the inner heat absorption pipe, between two adjacent pipes in the outer heat absorption pipe and between two adjacent pipes in the inner heat absorption pipe; the heat collector also comprises a first selective absorption coating, a second selective absorption coating, a third selective absorption coating and a fourth selective absorption coating; the selective absorption coating I is coated on the half circumference of the far-sun side of the external heat absorption pipe, the selective absorption coating II is coated on the half circumference of the near-sun side of the external heat absorption pipe, the selective absorption coating III is coated on the half circumference of the far-sun side of the internal heat absorption pipe, and the selective absorption coating IV is coated on the half circumference of the near-sun side of the internal heat absorption pipe.

2. The tower-type solar thermal power generation system based on the cavity-column collector of claim 1, wherein: the near-sun heliostat field and the far-sun heliostat field divide the whole heliostat field into two fan-shaped areas.

3. The tower-type solar thermal power generation system based on the cavity-column collector of claim 1, wherein: the outer heat absorption tube set and the inner heat absorption tube set are concentrically arranged.

4. The tower-type solar thermal power generation system based on the cavity-column collector of claim 1, wherein: the outer heat absorption pipe forms a steam evaporator, and the inner heat absorption pipe forms a steam superheater.

5. The tower-type solar thermal power generation system based on the cavity-column collector of claim 3, wherein: the angle of the fan-shaped opening is the same as that of a fan-shaped area of the field of the heliostat close to the sun.

6. The tower-type solar thermal power generation system based on the cavity-column collector of claim 1, wherein: the outer heat absorption pipes and the inner heat absorption pipes are distributed in a staggered mode.

7. The tower-type solar thermal power generation system based on the cavity-column collector of claim 1, wherein: the absorptivity of the selective absorption coating layer III is lower than that of the selective absorption coating layer IV.

8. The tower-type solar thermal power generation system based on the cavity-column collector of claim 1, wherein: the absorption rate of the first selective absorption coating is lower than that of the second selective absorption coating.

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