Anti-seismic containment outer frame for vertical storage tanks

Abstract

The present application belongs to the technical field of heat storage system of photo-thermal power station, and relates to an anti-seismic constraint outer frame suitable for a molten salt vertical storage tank in a high seismic intensity area. The present application comprises a heat preservation layer, a multi-layer ring beam, an interlayer column, a steel sheet rib and a flexible steel cable. The heat preservation layer is used for coating the storage tank, and has a ring-shaped protrusion extending along the circumference of the storage tank, and the inner side of the ring-shaped protrusion forms a ring-shaped cavity; the multi-layer ring beam is arranged at intervals along the height direction of the tank wall; the interlayer column connects two adjacent ring beams, and the ring beam and the interlayer column form an integral frame which is placed on the ring-shaped protrusion; the steel sheet rib is arranged in the ring-shaped cavity, and is arranged at intervals along the circumference of the storage tank; one end of the flexible steel cable is fixedly connected with the ring beam located at the uppermost layer, and the other end is used for being fixed to the ground. The present application simultaneously realizes three functions of vertical anchoring, lateral constraint and tank wall stabilization without affecting the normal temperature deformation and heat preservation performance of the storage tank.

Description

Technical Field

[0001] This invention belongs to the technical field of solar thermal power plant thermal storage systems, and relates to an anti-seismic constraint outer frame for vertical storage tanks. Background Technology

[0002] Molten salt thermal energy storage system is the core energy storage unit of solar thermal power plant. It uses binary or ternary nitrate molten salt as the thermal storage medium and operates in a dual-tank mode of cold tank-hot tank. It stores thermal energy when there is sufficient solar radiation and releases thermal energy at night or on cloudy or rainy days, thereby realizing the continuous and stable power output of solar thermal power plant. It is the fundamental guarantee for the power plant to get rid of the intermittent constraints of weather.

[0003] In high seismic intensity zones, conventional storage tanks require vertical anchoring measures according to regulations. However, molten salt storage tanks have multiple layers of insulation material at the bottom to form a thermal insulation layer, making conventional penetrating anchoring methods unsuitable. Forcing such anchoring would create thermal bridging effects and temperature-constrained stress, and could even damage the tank bottom seal. Furthermore, existing wind-resistant rings and reinforcing rings are primarily designed for wind pressure conditions, lacking effective constraints on buckling instability deformation of the tank wall under seismic cyclic loads. They also struggle to coordinate free thermal expansion and contraction under large temperature cycles, failing to meet the seismic stability requirements of high-intensity zones. Summary of the Invention

[0004] The purpose of this invention is to provide a seismic restraint outer frame for vertical storage tanks, in order to solve the technical problems in the prior art where molten salt storage tanks cannot be anchored using conventional anchoring methods, and where existing measures are difficult to effectively restrain tank wall deformation, resulting in the risk of tank wall instability and failure.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a seismic-resistant restraint outer frame for vertical storage tanks, comprising: An insulation layer for covering a storage tank, the insulation layer having annular protrusions extending circumferentially along the storage tank, and annular cavities formed on the inner side of the annular protrusions; Multi-layered ring beams are arranged at intervals along the height of the tank wall; Interlayer columns connecting two adjacent ring beams, the ring beams and the interlayer columns forming an integral frame, the integral frame resting on the annular protrusion; The steel ribs are disposed within the annular cavity and are spaced apart along the circumference of the storage tank. A flexible steel cable, one end of which is fixedly connected to the uppermost ring beam, and the other end of which is fixed to the ground.

[0006] Furthermore, the ring beam has three layers: a top ring beam, a middle ring beam, and a lower ring beam. The lower ring beam is placed on the annular protrusion. The interlayer columns include an upper column connecting the top ring beam and the middle ring beam, and a lower column connecting the middle ring beam and the lower ring beam.

[0007] Furthermore, the top-layer ring beam, the middle-layer ring beam, and the lower-layer ring beam are arranged at equal intervals; the upper-layer columns are arranged at equal intervals; and the lower-layer columns are arranged at equal intervals.

[0008] Furthermore, the flexible steel cables are evenly arranged along the circumference of the storage tank.

[0009] Furthermore, turnbuckles are provided on the flexible steel cable for adjusting the tension of the flexible steel cable.

[0010] Furthermore, when the storage tank is full of salt and the external ambient temperature exceeds a preset temperature, the flexible steel cable is adjusted to a taut state via the turnbuckle.

[0011] Furthermore, the flexible steel cable has a ground fixing point at one end for fixing to the ground, and the flexible steel cable is anchored to the ground through the ground fixing point.

[0012] Furthermore, a gap is left in the radial direction between the overall frame and the insulation layer.

[0013] Furthermore, the steel ribs are arranged vertically to provide vertical anchoring to the storage tank via the flexible steel cables under seismic action.

[0014] Furthermore, the ring beam is a ring-shaped steel beam, the inter-layer column is a vertical steel column, and the ring beam and the inter-layer column are fixedly connected.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention involves installing multiple layers of ring beams and interlayer columns along the height of the outer wall of a storage tank, connecting the uppermost ring beam to the ground with flexible steel cables, and simultaneously installing steel ribs within the annular cavity of the insulation layer at the bottom of the tank. The overall frame, consisting of the ring beams and interlayer columns, rests on the annular protrusions of the insulation layer. The overall frame achieves vertical support through the annular protrusions of the insulation layer, eliminating the need to penetrate the insulation layer or perform welding work on the tank, thus preserving the integrity of the original tank structure. When an earthquake occurs, the uppermost ring beam, through flexible steel cables, limits the further tilting of the tank, preventing it from overturning. The middle ring beam and interlayer columns form an integral ring around the outside of the tank wall, restraining radial deformation and maintaining stability. The steel ribs provide vertical anchoring to the tank through steel cables, preventing it from detaching from the foundation. Thus, without affecting the tank's normal temperature deformation and insulation performance, it simultaneously achieves three functions: vertical anchoring, lateral restraint, and tank wall stability. This effectively solves the technical problem that conventional anchoring measures cannot be used for molten salt tanks in high seismic intensity areas, and that the tank wall is prone to instability and failure.

[0016] This invention employs a three-layered ring beam system: a top-layer ring beam, a middle-layer ring beam, and a bottom-layer ring beam. These three layers are distributed along the height of the tank wall, simultaneously forming circumferential constraints at the upper, middle, and lower parts of the tank. The top-layer ring beam is connected to the ground by steel cables, providing lateral restraint and overturning control. The middle-layer ring beam is located in the area of ​​greatest lateral deformation of the tank wall, providing deformation restraint. The bottom-layer ring beam, in conjunction with steel ribs, provides vertical anchoring. The three layers of ring beams are connected by inter-layer columns to work collaboratively as a whole, resulting in a more rational distribution of the seismic resistance of the outer frame.

[0017] This invention arranges flexible steel cables evenly along the circumference of the storage tank, so that the lateral constraints of the steel cables on the storage tank are evenly distributed in the circumference and the constraints in each direction are balanced. This avoids the difference in seismic response direction caused by uneven steel cable arrangement and improves the adaptability of the outer frame to seismic action in any direction.

[0018] This invention achieves precise control of the cable tension by setting turnbuckles on the steel cable and utilizing the thread adjustment function of the turnbuckles. This effectively compensates for the cable slack caused by temperature deformation, ensuring that the steel cable can play a restraining role during an earthquake and avoiding restraint delay or failure caused by cable slack.

[0019] This invention provides a stable and reliable ground anchorage end for the steel cable by setting a ground fixing point at one end of the steel cable, thus ensuring the effective transmission of the cable tension and reliable anchorage.

[0020] This invention establishes a radial gap between the overall frame and the insulation layer. Under normal operating conditions, the overall frame and the insulation layer do not contact each other, thus avoiding any additional constraint on the storage tank. When the storage tank undergoes normal expansion and contraction due to temperature changes, this gap provides free deformation space, ensuring that the outer frame does not affect the normal temperature deformation of the storage tank. Simultaneously, the gap also prevents frictional damage between the overall frame and the insulation layer, guaranteeing the integrity and durability of the insulation layer.

[0021] This invention arranges the steel ribs vertically, resulting in high vertical stiffness and low horizontal stiffness. High vertical stiffness ensures effective transmission of vertical anchoring force under seismic loads; low horizontal stiffness avoids the steel ribs constraining the normal temperature deformation of the storage tank.

[0022] This invention uses a ring beam as a ring-shaped steel beam and inter-story columns as vertical steel columns. The ring-shaped steel beam has superior circumferential load-bearing performance, effectively withstanding circumferential tensile and compressive forces; the vertical steel columns have high vertical stiffness and bearing capacity, reliably transmitting vertical loads and bending moments. The two are fixedly connected to form a rigid frame, possessing good integrity and redundancy. Even if some components are damaged, the overall frame can still maintain a certain degree of constraint function. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the overall arrangement of the components of the present invention; Figure 2 This is a partial schematic diagram of the positioning of the lower ring beam and the installation of the steel ribs in this invention; Figure 3 This is a schematic diagram of the connection between the ring beam and the inter-layer columns of the present invention.

[0024] Among them: 1. Storage tank; 2. Top ring beam; 3. Middle ring beam; 4. Lower ring beam; 5. Interlayer column; 51. Upper column; 52. Lower column; 6. Flexible steel cable; 7. Turnbuckle; 8. Ground fixing point; 9. Steel rib; 10. Insulation layer; 11. Annular protrusion; 12. Annular cavity. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 and Figure 2 The present invention provides an anti-seismic restraint outer frame for vertical storage tanks, including an insulation layer 10, multi-layer ring beams, interlayer columns 5, steel ribs 9, and flexible steel cables 6.

[0028] The insulation layer 10 is used to cover the outer surface of the storage tank 1 to reduce heat loss. The insulation layer 10 has annular protrusions 11 extending circumferentially from the bottom region of the storage tank 1, protruding outwards from the surface of the insulation layer 10. An annular cavity 12 is formed inside the annular protrusions 11, and steel ribs 9 are disposed within the annular cavity 12, located between the insulation layer 10 and the storage tank 1. The steel ribs 9 are arranged at equal intervals along the circumference of the storage tank 1, are vertically arranged steel ribs, and are relatively short, thus not restricting the deformation of the molten salt storage tank under temperature action. The steel ribs 9 are located within the annular cavity 12 on the outer wall of the storage tank 1, maintaining contact with the outer wall of the storage tank 1. When an earthquake occurs, they can respond promptly to the vertical displacement of the storage tank 1, with a short force transmission path and rapid response. The steel ribs 9 are used to provide vertical anchoring to the storage tank 1 via steel cables under seismic action.

[0029] In a preferred embodiment of the present invention, the ring beam has three layers: a top ring beam 2, a middle ring beam 3, and a lower ring beam 4, with the lower ring beam 4 resting on the annular protrusion 11. The interlayer columns 5 include an upper column 51 connecting the top ring beam 2 and the middle ring beam 3, and a lower column 52 connecting the middle ring beam 3 and the lower ring beam 4. The ring beams are annular steel beams, which have superior circumferential load-bearing performance and can effectively withstand circumferential tension and compression. The interlayer columns 5 are vertical steel columns, which have high vertical stiffness and bearing capacity, and can reliably transmit vertical loads and bending moments. The ring beams and interlayer columns 5 are fixedly connected by welding or bolts. The three layers of ring beams are connected by the interlayer columns 5 to form an integral frame, creating a rigid frame with good integrity and redundancy. Even if some components are damaged, the overall frame can still maintain a certain degree of constraint function. This invention employs a three-layered ring beam system: a top-layer ring beam, a middle-layer ring beam, and a bottom-layer ring beam. These three layers are distributed along the height of the tank wall, simultaneously forming circumferential constraints at the upper, middle, and lower parts of the tank. The top-layer ring beam is connected to the ground by steel cables, providing lateral restraint and overturning control. The middle-layer ring beam is located in the area of ​​greatest lateral deformation of the tank wall, providing deformation restraint. The bottom-layer ring beam, in conjunction with steel ribs, provides vertical anchoring. The three layers of ring beams are connected by inter-layer columns to work collaboratively as a whole, resulting in a more rational distribution of the seismic resistance of the outer frame.

[0030] In a preferred embodiment of the present invention, the top ring beam 2, the middle ring beam 3, and the lower ring beam 4 are arranged at equal intervals; the upper columns 51 are arranged at equal intervals; and the lower columns 52 are arranged at equal intervals. This equal-interval arrangement facilitates uniform stress distribution and avoids stress concentration.

[0031] See Figure 3 The ring beams and inter-layer columns 5 are fixedly connected to form an integral frame structure. The ring beams are arranged at intervals along the height of the tank wall of the storage tank 1. The inter-layer columns 5 vertically connect adjacent ring beams, making the constraint spacing of each layer of ring beams along the height of the storage tank uniform, thus avoiding local deformation concentration caused by uneven constraint spacing. At the same time, the upper-layer columns are arranged at equal intervals, and the lower-layer columns are arranged at equal intervals, making the constraint spacing of each layer of columns along the circumference of the storage tank uniform, resulting in more balanced stress distribution and avoiding local stress concentration caused by uneven column spacing. This gives the entire frame sufficient rigidity and integrity.

[0032] The integral frame, consisting of the ring beam and interlayer columns 5, is arranged outside the insulation layer 10, with its bottom resting on the annular protrusion 11 of the insulation layer 10. By resting the integral frame on the annular protrusion 11 of the insulation layer 10, the weight of the integral frame is transferred to the insulation layer 10 and the bottom foundation of the storage tank 1 through the annular protrusion 11. This eliminates the need for opening holes or welding additional connectors on the tank wall of the storage tank 1, ensuring the integrity of the tank wall and the continuity of the insulation layer 10, and avoiding thermal bridging effects caused by connection structures. The insulation layer 10 is located between the integral frame and the storage tank 1, ensuring that the integral frame does not directly contact the storage tank 1, thus not affecting the insulation performance of the storage tank 1. A radial gap is left between the integral frame and the insulation layer 10. Under normal operating conditions, the integral frame does not contact the insulation layer and does not exert additional constraint on the storage tank. When the storage tank undergoes normal expansion and contraction deformation due to temperature changes, this gap provides free deformation space for the storage tank, ensuring that the outer frame does not affect the normal temperature deformation of the storage tank. At the same time, the gaps also prevent frictional damage between the overall frame and the insulation layer, ensuring the integrity and durability of the insulation layer.

[0033] One end of the flexible steel cable 6 is fixedly connected to the top ring beam 2, and the other end is fixed to the ground through a ground fixing point 8. The ground fixing point 8 provides a stable and reliable ground anchorage end for the steel cable, ensuring effective transmission of tension and reliable anchorage. The flexible steel cable 6 is evenly distributed around the circumference of the storage tank 1 to prevent large swaying of the upper part of the storage tank 1 under seismic action. This ensures that the lateral restraint of the steel cable on the storage tank is evenly distributed in the circumferential direction. Regardless of the direction of the seismic excitation, there are steel cables in the optimal stress direction, and the restraint is balanced in all directions. This avoids the difference in seismic response direction caused by uneven steel cable distribution and improves the adaptability of the outer frame to seismic action in any direction. Turnbuckles 7 are installed on the flexible steel cable 6 to adjust the tension of the flexible steel cable 6. By adjusting the turnbuckles 7, when the storage tank 1 is full of salt and the external ambient temperature exceeds the preset temperature, the flexible steel cable 6 is kept in a taut state, effectively compensating for the slack of the steel cable caused by temperature deformation. This ensures that the steel cable can quickly exert its restraining effect during an earthquake and avoids restraint delay or failure caused by steel cable slack.

[0034] The working principle of the entire seismically restrained outer frame of this invention is as follows: Under normal circumstances, due to the flexibility of the flexible steel cable 6 and the adjustment function of the turnbuckle 7, there is a gap in the radial direction between the overall frame and the insulation layer 10, so the entire outer frame will not restrict the normal deformation of the storage tank 1 under temperature.

[0035] When an earthquake occurs, the following three scenarios may occur: First, if tank 1 tilts, the top ring beam 2 will limit the further development of the tilt through the flexible steel cables 6 connected to it, thus preventing the tank from overturning. The flexible steel cables 6 are evenly distributed around the circumference of tank 1, with balanced constraints in all directions, and can effectively function regardless of the direction of the seismic excitation.

[0036] Secondly, if the molten salt exerts significant lateral pressure on the tank wall, causing radial deformation, the intermediate ring beam 3 and interlayer columns 5 will prevent further deformation. The three ring beams and interlayer columns 5 form an integral ring around the circumference of the storage tank 1, increasing the stability of the tank wall. The intermediate ring beam 3 is located in the middle region along the height of the tank wall, which is the area with the greatest lateral deformation. Placing the intermediate ring beam 3 here can most effectively constrain the deformation of the tank wall.

[0037] Third, when a vertical earthquake occurs, the storage tank 1 has an upward displacement tendency. Since the steel rib 9 is located in the annular cavity 12 on the outer wall of the storage tank 1, when the storage tank 1 moves upward, the steel rib 9 is driven upward by the storage tank 1, and then the upward force is transmitted to the overall frame through the annular protrusion 11. Finally, the storage tank 1 is held in place by the flexible steel cable 6, which plays a vertical anchoring role and prevents the storage tank from detaching from the foundation.

[0038] By adjusting the turnbuckle 7, when the salt tank is full of salt and the external ambient temperature is high, the flexible steel cable 6 is kept in a taut state, ensuring that the flexible steel cable 6 can quickly play a restraining role in the event of an earthquake.

[0039] This invention constructs an overall frame by setting up multiple layers of ring beams and interlayer columns 5 on the outer side of the tank wall of the storage tank 1. The annular protrusions 11 of the insulation layer 10 provide vertical support for the overall frame, achieving seismic restraint without penetrating the insulation layer 10 or welding the storage tank 1. Steel ribs 9 are installed in the annular cavity 12 between the insulation layer 10 and the storage tank 1 at the bottom of the tank. Flexible steel cables 6 are connected between the uppermost ring beam and the ground, forming a multi-layered seismic restraint system. By setting the ring beams in three layers, they respectively undertake three different functions: overturning control, tank wall deformation restraint, and vertical anchoring. By arranging the ring beams and columns of each layer at equal intervals, the restraint spacing is uniform, avoiding local deformation concentration or stress concentration. By arranging the flexible steel cables 6 evenly along the circumference of the storage tank 1, the restraint in all directions is balanced. By setting turnbuckles 7 on the flexible steel cables 6, when the storage tank 1 is full of salt and the external ambient temperature is high, the flexible steel cables 6 are adjusted to a taut state, effectively compensating for the slack of the steel cables caused by temperature deformation. When an earthquake occurs, the top ring beam 2 restrains the upper part of the storage tank 1 to control overturning through the flexible steel cable 6. The middle ring beam 3 and the interlayer column 5 form an integral hoop to restrain the radial deformation of the tank wall. The steel ribs 9, together with the flexible steel cable 6, provide vertical anchoring to prevent the storage tank 1 from detaching from the foundation. At the same time, there is a gap in the radial direction between the overall frame and the insulation layer 10, which provides free space for temperature deformation of the storage tank 1 under normal operating conditions. Thus, without affecting the normal temperature deformation and insulation performance of the storage tank 1, the three functions of overturning control, tank wall stability and vertical anchoring are achieved at the same time. This effectively solves the technical problem that conventional anchoring measures cannot be used for molten salt storage tanks in high seismic intensity areas and the tank wall is prone to instability and failure.

[0040] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A seismic-resistant restraint outer frame for vertical storage tanks, characterized in that, include: The insulation layer (10) used to cover the storage tank (1) has an annular protrusion (11) extending circumferentially along the storage tank (1), and an annular cavity (12) is formed on the inner side of the annular protrusion (11). Multi-layered ring beams are arranged at intervals along the height of the tank wall (1); Interlayer columns (5) connecting two adjacent ring beams, the ring beams and the interlayer columns (5) form an overall frame, and the overall frame rests on the annular protrusion (11); The steel ribs (9) are provided in the annular cavity (12) and are arranged at intervals along the circumference of the storage tank (1); A flexible steel cable (6) is provided, one end of which is fixedly connected to the uppermost ring beam, and the other end is used to fix it to the ground.

2. The seismic restraint outer frame for vertical storage tanks according to claim 1, characterized in that, The ring beam has three layers: a top ring beam (2), a middle ring beam (3), and a lower ring beam (4). The lower ring beam (4) is placed on the annular protrusion (11). The interlayer column (5) includes an upper column (51) connecting the top ring beam (2) and the middle ring beam (3), and a lower column (52) connecting the middle ring beam (3) and the lower ring beam (4).

3. The seismic restraint outer frame for vertical storage tanks according to claim 2, characterized in that, The top ring beam (2), the middle ring beam (3) and the lower ring beam (4) are arranged at equal intervals; the upper columns (51) are arranged at equal intervals; and the lower columns (52) are arranged at equal intervals.

4. The seismic restraint outer frame for vertical storage tanks according to claim 1, characterized in that, The flexible steel cable (6) is evenly arranged around the circumference of the storage tank (1).

5. The seismic restraint outer frame for vertical storage tanks according to claim 1, characterized in that, The flexible steel cable (6) is provided with turnbuckles (7) for adjusting the tension of the flexible steel cable (6).

6. The seismic restraint outer frame for vertical storage tanks according to claim 5, characterized in that, When the storage tank (1) is full of salt and the external ambient temperature exceeds the preset temperature, the flexible steel cable (6) is adjusted to a tensioned state by the turnbuckle (7).

7. The seismic restraint outer frame for vertical storage tanks according to claim 1, characterized in that, The flexible steel cable (6) is fixed to the ground at one end with a ground fixing point (8), and the flexible steel cable (6) is anchored to the ground through the ground fixing point (8).

8. The seismic restraint outer frame for vertical storage tanks according to claim 1, characterized in that, A gap is left in the radial direction between the overall frame and the insulation layer (10).

9. The seismic restraint outer frame for vertical storage tanks according to claim 1, characterized in that, The steel ribs (9) are arranged vertically to provide vertical anchoring to the storage tank (1) via the flexible steel cable (6) under seismic action.

10. The seismic restraint outer frame for vertical storage tanks according to claim 1, characterized in that, The ring beam is a ring-shaped steel beam, and the inter-layer column (5) is a vertical steel column. The ring beam and the inter-layer column (5) are fixedly connected.

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