Transverse parallel double-tank body for supercritical carbon dioxide

Abstract

The invention provides a supercritical carbon dioxide transversely-arranged parallel-connection type double-tank body which comprises a hot storage tank and a cold storage tank which are transversely arranged in parallel, the hot storage tank and the cold storage tank each comprise a tank body, an inlet pipeline is arranged in an inner cavity of each tank body, one end of each inlet pipeline is connected with an inlet of the corresponding tank body, and the other end of each inlet pipeline is connected with an outlet of the corresponding tank body. The other end of the tank body is sequentially connected with a transition pipeline, a reducing pipeline and an outlet pipeline, and the outlet pipeline is connected with an outlet of the tank body; a plurality of small round holes are formed in the transition pipeline in the axial direction of the transition pipeline; the design of a drainage pipeline formed by combining the inlet pipeline, the transition pipeline, the reducing pipeline and the outlet pipeline is adopted in the tank body, strong relative movement is avoided, and therefore pressure loss is reduced.

Description

Technical Field

[0001] The invention belongs to the field of supercritical working medium storage tanks, and in particular relates to a transversely arranged parallel double tank body of supercritical carbon dioxide. Background Art

[0002] With the continuous growth of global energy demand and the pursuit of sustainable development goals, improving energy efficiency has become a common focus of governments, scientific research institutions and industries. In this context, the supercritical carbon dioxide Brayton cycle, as a new type of power generation technology, has attracted widespread attention due to its high efficiency, economic benefits and environmental friendliness. Compared with the traditional Brayton cycle technology, the supercritical CO2 cycle has significant advantages. One of the key factors is the high fluid density of supercritical carbon dioxide, which enables researchers to design compact turbines and compressors. The compactness of the power generation system can not only effectively reduce the material manufacturing cost, but also meet the modern industrial needs of miniaturization and lightweight. In addition, the supercritical carbon dioxide power cycle has many other advantages, such as high-efficiency operation, low noise and vibration, and emission-free closed cycle. Its application power range is wide, ranging from 100 kW to 100 MW, and it can adapt to different types of heat sources, so it is considered to be a new generation of power technology with revolutionary potential.

[0003] As one of the key components, the storage tank plays a vital role in the supercritical carbon dioxide power generation cycle. In view of the special requirements of the supercritical carbon dioxide power cycle for temperature and pressure, the storage tank stores and supplies the carbon dioxide working fluid in the entire circulation system, ensuring the normal operation of the entire system and its key core power components, especially in the whole process of starting, speed increase, efficient operation, and shutdown, and providing adjustable dynamic response to play a role in voltage stabilization.

[0004] In the development of supercritical carbon dioxide power cycle, near-critical point operation has been proven to have many benefits. However, the thermal properties of carbon dioxide near the critical point are extremely unstable, and its physical quantities such as density are extremely sensitive to changes in temperature and pressure. Therefore, precise control of temperature and pressure through tanks and valves is a necessary prerequisite for the development of this technology. In addition, carbon dioxide in the tank undergoes obvious phase changes and stratification due to temperature and pressure fluctuations, which will reduce the heating and insulation effects of the tank, and have an extremely adverse effect on the safety of the tank itself and even the entire system. In addition, when carbon dioxide flows into and out of the tank, it will produce relative motion with the original static working medium inside, forming a highly complex flow phenomenon such as a vortex structure and coupled secondary flow, resulting in a large pressure loss, resulting in reduced cycle efficiency. This is also an aspect that needs to be improved in supercritical carbon dioxide tanks. Summary of the invention

[0005] The purpose of the present invention is to provide a horizontally parallel double tank of supercritical carbon dioxide, which solves the defect that the existing supercritical carbon dioxide in the storage tank is prone to obvious phase change and stratification due to temperature and pressure fluctuations, making the storage tank less safe.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a transversely parallel double tank body of supercritical carbon dioxide, comprising a hot storage tank and a cold storage tank arranged transversely in parallel, wherein the hot storage tank and the cold storage tank both comprise a tank body, an inlet pipe is arranged in the inner cavity of the tank body, one end of the inlet pipe is connected to the inlet of the tank body, and the other end is connected in sequence to a transition pipe, a tapered pipe and an outlet pipe, wherein the outlet pipe is connected to the outlet of the tank body; Preferably, the transition duct is provided with a plurality of circular holes along its axial direction.

[0007] Preferably, the transition duct is a spiral structure.

[0008] Preferably, the inlets of the hot storage tank and the cold storage tank are connected in parallel via a first three-way pipe, and a one-way valve is provided on the first three-way pipe.

[0009] Preferably, the outlets of the hot storage tank and the cold storage tank are connected in parallel via a second three-way pipe, and a three-way regulating valve is provided on the second three-way pipe.

[0010] Preferably, a thermometer and a pressure gauge are provided on the second three-way pipe.

[0011] Preferably, safety valves are provided at the inlets of the hot storage tank and the cold storage tank.

[0012] Preferably, the hot storage tank and the cold storage tank are placed side by side and horizontally on a fixed base.

[0013] Preferably, the tapered pipe is a hollow frustum-shaped structure, a small end of which is connected to the outlet pipe, and a large end of which is connected to the transition pipe.

[0014] Preferably, an electric heating belt is arranged on the outer wall of the heat storage tank.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a horizontally parallel double tank for supercritical carbon dioxide, which is designed to solve many problems caused by the special characteristics of supercritical carbon dioxide as a supercritical state. It is essentially different from traditional liquid storage tanks or gas storage tanks. The specific differences are as follows: Traditional storage tanks are arranged vertically due to the different densities of gas or liquid, and are designed to be top-in and bottom-out or bottom-in and top-out according to the density to achieve the best storage effect. However, due to the particularity of the supercritical state, its physical properties are extremely unstable, and its density is greatly affected by temperature. At the same time, since the actual engineering is basically operated near the critical point, changes in temperature and pressure can easily cause the working fluid to change phase from the supercritical state to the gas or liquid state.

[0016] The present invention adopts a horizontally placed tank body for the above two reasons. Since the physical properties of the supercritical state are unstable, the supercritical state and the gas-liquid two-phase coupling and mixing will occur when flowing in and out of the tank body. The flowing working fluid and the original static working fluid inside produce complex relative motion, forming a vortex structure and highly complex flow phenomena coupled with secondary flow, which produces a large pressure loss and reduces the circulation efficiency. The present invention adopts a drainage pipe design composed of an inlet pipe, a transition pipe, a tapered pipe and an outlet pipe in the tank body, which avoids strong relative motion and reduces pressure loss.

[0017] Because the thermal properties of the supercritical state are extremely sensitive, phase change and stratification are prone to occur in the storage tank. If the phase change occurs in the drainage pipe, it is very likely to cause blockage. The present invention innovatively designs a transition pipe, and small holes are opened on the pipe wall, through which the fluid in the pipe and the fluid in the storage tank can achieve material exchange. At the same time, with the help of the flowing working fluid in the pipe, the working fluid in the storage tank is also mixed and stirred to a certain extent, thereby effectively reducing the adverse phenomena such as stratification and even phase change caused by temperature sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a top view structural diagram of the device of the present invention; Figure 2 It is the internal structure diagram of the storage tank of the present invention; Among them: 1-hot storage tank, 2-cold storage tank, 3-check valve, 4-safety valve, 5-three-way regulating valve, 6-thermometer, 7-pressure gauge, 8-fixed base, 9-electric heating tape, 10-tank inlet, 11-inlet pipe, 12-transition pipe, 13-tapered pipe, 14-outlet pipe. DETAILED DESCRIPTION

[0019] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0020] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0021] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0022] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0023] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0024] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0025] Example 1 This embodiment provides a horizontally parallel double tank body of supercritical carbon dioxide, including a hot storage tank 1 and a cold storage tank 2, wherein the hot storage tank 1 and the cold storage tank 2 are horizontally arranged side by side on a fixed base 8.

[0026] The inlets of the hot storage tank 1 and the cold storage tank 2 are connected via a first three-way pipe, and the outlets of the hot storage tank 1 and the cold storage tank 2 are connected via a second three-way pipe.

[0027] The second three-way pipe is provided with a three-way regulating valve 5 , a thermometer 6 and a pressure gauge 7 .

[0028] A safety valve 4 is provided at the inlet of the hot storage tank 1 and the cold storage tank 2 to ensure the safety of the device under accident conditions.

[0029] A one-way valve 3 is provided on the first three-way pipe. The one-way valve is located at the inlet of the whole device to ensure that the working fluid flows in one direction in the cycle after the device is connected to the system. After flowing through the one-way valve, the working fluid enters the hot storage tank and the cold storage tank respectively through the three-way structure.

[0030] The hot storage tank 1 and the cold storage tank 2 have the same structure and both include a tank body, in which an inlet pipe 11, a transition pipe 12 and a tapered pipe 13 are arranged in the inner cavity of the tank body, wherein one end of the inlet pipe 11 is communicated with the tank body inlet 10, the other end of the inlet pipe 11 is connected to the transition pipe 12, the free end of the transition pipe 12 is connected to the large end of the tapered pipe 13, and the small end of the tapered pipe 13 is connected to the outlet pipe 14; the outlet pipe 14 is placed at the outlet of the tank body and connected to the tank body outlet.

[0031] The transition duct 12 is a spiral structure.

[0032] The tank body of the heat storage tank 1 is provided with an electric heating belt 9, which can heat and keep the working fluid inside the heat storage tank warm; the two sides of the tank body are respectively connected to the inlet pipe and the outlet pipe of the working fluid.

[0033] The working process of this embodiment: When the working fluid enters the device, it flows through the one-way valve 3 and enters the first three-way pipe, and then is divided into two paths to enter the hot storage tank 1 and the cold storage tank 2 respectively. After entering the storage tank, it first flows through the inlet pipe 11 and enters the transition pipe 12. The working fluid that has undergone phase change in the transition pipe 12 will exchange substances with the original working fluid in the tank body through the circular small holes, and further reach the outlet pipe 14 under the guidance of the tapered pipe 13. Under the action of the circular small holes, the stratification phenomenon of the working fluid in the tank body is weakened.

[0034] If it is in a hot storage tank, the electric heating tape 9 will be used to fully heat it during the process of flowing through the transition pipe 12. Under the action of the drainage pipe composed of the inlet pipe 11, the transition pipe 12 and the tapered pipe 13, the working fluid avoids the loss caused by relative movement and reduces the pressure resistance of the process. After flowing out from the tank outlet, the two streams of working fluid, cold and hot, will enter the second three-way pipe and mix under the action of the three-way regulating valve 5, and finally flow out from the device outlet and enter the subsequent components of the circulation system.

[0035] Example 2 Based on Example 1, this embodiment provides a horizontally parallel double tank for supercritical carbon dioxide, wherein the central axis at the inlet of the transition pipe is aligned with the inlet pipe, the transition pipe itself is smooth everywhere and spirally surrounds the interior of the tank, and is provided with a number of circular holes, and the central axis of the cross section of the outlet end is aligned with the central axis of the tapered pipe and the outlet pipe.

[0036] The tapered pipe is located before the outlet pipe, and the overall structure is a hollow frustum, and the central axis thereof is aligned with the inlet pipe, the end of the transition pipe and the outlet pipe.

[0037] Example 3 On the basis of Example 1, this example provides a horizontally placed parallel double tank of supercritical carbon dioxide, wherein the transition pipe 13 is provided with a plurality of circular holes along its axial direction.

[0038] Due to the extremely sensitive thermal properties of the supercritical state, phase change and stratification are prone to occur in the storage tank. If the phase change occurs in the drainage pipe, it is very likely to cause blockage. This embodiment innovatively designs a transition pipe, and small holes are opened on its wall, through which the fluid in the pipe and the fluid in the storage tank can achieve material exchange. At the same time, with the help of the flowing working fluid in the pipe, the working fluid in the storage tank is also mixed and stirred to a certain extent, thereby effectively reducing the adverse phenomena such as stratification and even phase change caused by temperature sensitivity.

[0039] Example 4 This embodiment provides a control method for a supercritical carbon dioxide horizontally connected parallel dual tank, comprising the following steps: Step 1, obtaining temperature information and pressure information at the outlet of the double tank; Step 2, adjusting the three-way regulating valve 5 at the outlet according to the collected temperature and pressure. The three-way regulating valve 5 adjusts the ratio of the high-temperature carbon dioxide working fluid and the low-temperature carbon dioxide working fluid by adjusting the opening of the two tank outlets, and mixes them at the outlet, thereby controlling the working fluid temperature flowing out of the device outlet.

[0040] In the heat storage tank, the start and stop of the electric heating tape is adjusted in real time according to the collected temperature to ensure that the working fluid in the heat storage tank 1 is heated to 50°C.

[0041] When an accident occurs, the safety valves at the front ends of the two storage tanks are activated to ensure the safety of the device and the circulation.

[0042] Since the physical properties of the supercritical state are unstable, the supercritical state and the gas-liquid two-phase coupling and mixing will occur when flowing in and out of the tank body, and the flowing working medium and the original static working medium inside will produce complex relative motion, forming a vortex structure and highly complex flow phenomena coupled with secondary flow, resulting in a large pressure loss, resulting in a decrease in circulation efficiency. The present invention adopts a drainage pipe design composed of an inlet pipe, a transition pipe, a tapered pipe and an outlet pipe in the tank body, which avoids strong relative motion and thus reduces pressure loss.

[0043] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A horizontally parallel double tank of supercritical carbon dioxide, characterized in that: The invention comprises a hot storage tank and a cold storage tank which are arranged in parallel horizontally, each of which comprises a tank body, an inlet pipe is arranged in the inner cavity of the tank body, one end of the inlet pipe is connected to the inlet of the tank body, and the other end is connected in sequence with a transition pipe, a tapered pipe and an outlet pipe, and the outlet pipe is connected to the outlet of the tank body.

2. The horizontally parallel double tank of supercritical carbon dioxide according to claim 1, characterized in that: The transition pipe is provided with a plurality of circular small holes along its axial direction.

3. The horizontally parallel double tank of supercritical carbon dioxide according to claim 1, characterized in that: The transition duct is a spiral structure.

4. The horizontally parallel double tank of supercritical carbon dioxide according to claim 1, characterized in that: The tapered pipe is a hollow frustum-shaped structure, a small end of which is connected to the outlet pipe, and a large end of which is connected to the transition pipe.

5. The horizontally parallel double tank of supercritical carbon dioxide according to claim 4, characterized in that: The inlets of the hot storage tank and the cold storage tank are connected in parallel through a first three-way pipe, and a one-way valve is arranged on the first three-way pipe.

6. The horizontally parallel double tank of supercritical carbon dioxide according to claim 1, characterized in that: The outlets of the hot storage tank and the cold storage tank are connected in parallel through a second three-way pipe, and a three-way regulating valve is arranged on the second three-way pipe.

7. The horizontally parallel double tank of supercritical carbon dioxide according to claim 1, characterized in that: The hot storage tank and the cold storage tank are placed side by side and horizontally on a fixed base.

8. The horizontally parallel double tanks of supercritical carbon dioxide according to claim 1, characterized in that: The second three-way pipe is provided with a thermometer and a pressure gauge.

9. The horizontally parallel double tanks of supercritical carbon dioxide according to claim 1, characterized in that: Safety valves are provided at the inlets of the hot storage tank and the cold storage tank.

10. The horizontally parallel double tank of supercritical carbon dioxide according to claim 1, characterized in that: An electric heating belt is arranged on the outer wall of the heat storage tank.

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