Nuclear power station gas-liquid mixing device

Abstract

The invention discloses a gas-liquid mixing device for a nuclear power station. The gas-liquid mixing device comprises a liquid inlet pipeline, a gas inlet pipeline, a fluid mixing pipeline and a fluid output pipeline, the gas inlet pipeline is communicated with the liquid inlet pipeline, and the liquid inlet pipeline, the fluid mixing pipeline and the fluid output pipeline are sequentially communicated; gas or a gas-liquid mixture is introduced into the gas inlet pipeline; a plurality of mixing elements arranged in the axial direction of the fluid mixing pipeline are arranged in the fluid mixing pipeline and comprise at least one first mixing element and at least one second mixing element, and flow channels of the first mixing elements and flow channels of the second mixing elements are arranged in a staggered mode. Bubble breaking and gas-liquid mixing are carried out through the first mixing element and the second mixing element which are arranged in the fluid mixing pipeline in a staggered mode, gas-liquid sufficient contact mixing is achieved, gas (such as hydrogen) dissolution is promoted, and therefore the concentration of dissolved hydrogen in a primary loop coolant can be maintained or increased.

Description

Technical Field

[0001] The invention relates to the technical field of gas-liquid mixing, and in particular to a gas-liquid mixing device for a nuclear power plant. Background Art

[0002] At present, during the normal operation of a pressurized water reactor nuclear power plant, it is generally adopted to maintain a certain concentration of dissolved hydrogen in the primary coolant to ensure the chemical environment conditions of the primary reducing water. Therefore, hydrogen must be continuously added to the primary liquid coolant, that is, a gas-liquid mixing operation is performed. The traditional coolant hydrogenation method in the chemical and volume control system (RCV) of a pressurized water reactor nuclear power plant is: the primary coolant discharged is sprayed in by the nozzle on the top of the control tank, and the mist coolant is fully in contact with the hydrogen in the gas phase in the control tank, so that the hydrogen is fully dissolved in the coolant, thereby completing the hydrogenation of the coolant. However, this hydrogenation method has the following defects: 1) The control box is covered with hydrogen, and a large amount of hydrogen is accumulated in the gas phase, which poses safety risks such as hydrogen explosion and fire; 2) The amount of hydrogenation required to adjust or maintain the hydrogen concentration of the primary coolant is completed by adjusting or controlling the gas phase pressure of the control box, and the dissolved hydrogen concentration of the primary coolant can only be adjusted slowly, which is time-consuming and has low adjustment accuracy; 3) The type of gas covering the control box needs to be changed during the startup and shutdown stages of the unit, that is, hydrogen is replaced with nitrogen, and then replaced with air. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a gas-liquid mixing device for a nuclear power plant.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a gas-liquid mixing device of a nuclear power plant, comprising: a liquid inlet pipeline, an air inlet pipeline, a fluid mixing pipeline and a fluid output pipeline.

[0005] The air inlet pipeline is connected with the liquid inlet pipeline, and the liquid inlet pipeline, the fluid mixing pipeline and the fluid output pipeline are connected in sequence; gas or a gas-liquid mixture is introduced into the air inlet pipeline.

[0006] A plurality of mixing elements are arranged in the fluid mixing pipeline along the axial direction thereof. The plurality of mixing elements include at least one first mixing element and at least one second mixing element. The flow channels of the first mixing element and the second mixing element are arranged alternately.

[0007] In some embodiments, the first first mixing element close to the inlet end of the fluid mixing channel is arranged in close contact with the first second mixing element, and the remaining mixing elements are arranged at intervals from the adjacent previous mixing elements.

[0008] In some embodiments, the medium flow rate in the fluid mixing pipeline is 0.6m / s to 1m / s. If the central axis of the fluid mixing pipeline is parallel to the horizontal plane, there is a first spacing L between the remaining mixing elements and the adjacent previous mixing elements, and the first spacing L is less than 600mm; if the central axis of the fluid mixing pipeline is perpendicular to the horizontal plane, there is a second spacing L' between the remaining mixing elements and the adjacent previous mixing elements, and the second spacing L' is less than 1800mm.

[0009] In some embodiments, when the central axis of the fluid mixing channel is parallel to the horizontal plane and the first spacing L is less than 200 mm, the remaining mixing elements include a plurality of first mixing elements and a plurality of second mixing elements that are alternately arranged.

[0010] In some embodiments, when the central axis of the fluid mixing channel is parallel to the horizontal plane and the first spacing L>350 mm, the remaining mixing elements include a plurality of first mixing elements.

[0011] In some embodiments, when the central axis of the fluid mixing pipe is parallel to the horizontal plane and 200 mm ≤ first spacing L ≤ 350 mm, the remaining mixing elements include a plurality of first mixing elements and a plurality of second mixing elements that are alternately arranged, or the remaining mixing elements include a plurality of first mixing elements.

[0012] In some embodiments, the mixing element is composed of a plurality of stacked corrugated sheets, the crests and troughs of the cross-sections of adjacent corrugated sheets are connected one-to-one, and / or adjacent corrugated sheets are connected by connecting sheets; the plane where the corrugated sheets of the first mixing element are located is perpendicular to the plane where the corrugated sheets of the second mixing element are located.

[0013] In some embodiments, the plane where the corrugated sheets of the first mixing element are located is perpendicular to the horizontal plane, and the plane where the corrugated sheets of the second mixing element are located is parallel to the horizontal plane.

[0014] In some embodiments, the corrugated sheet is formed by a plurality of corrugated units which are repeatedly arranged or arranged in sequence along the length direction, and the corrugated shape of the corrugated unit is at least one of V-shape, U-shape, Ω-shape and C-shape.

[0015] In some embodiments, the mixing elements arranged at intervals are connected and fixed by a support member, and the support member is a support frame, and the support frame is cylindrical or square.

[0016] In some embodiments, the outlet end of the air inlet pipe extends from the side wall of the liquid inlet pipe into the liquid inlet pipe and extends along the fluid flow direction.

[0017] In some embodiments, the air inlet pipe includes an air inlet pipe section, a bent pipe section and an air outlet pipe section, the air inlet pipe section is located on the outside of the liquid inlet pipe, and the bent pipe section and the air outlet pipe section are located inside the liquid inlet pipe; the air inlet pipe section is perpendicular to the central axis of the air outlet pipe section, and the air outlet pipe section is coaxially arranged with the liquid inlet pipe.

[0018] In some embodiments, the central axes of the liquid inlet pipe, the fluid mixing pipe and the fluid output pipe coincide with each other.

[0019] In some embodiments, the fluid mixing pipeline is detachably connected to the liquid inlet pipeline and the fluid output pipeline respectively, and the detachable connection is a flange connection, a snap connection or a threaded connection.

[0020] In some embodiments, the detachable connection is a flange connection, the inlet end and the outlet end of the fluid mixing pipe are respectively provided with a first flange and a second flange, the outlet end of the liquid inlet pipe is provided with a third flange connected to the first flange, and the inlet end of the fluid output pipe is provided with a fourth flange connected to the second flange, the first flange and the third flange are connected by a first fastener, and the second flange and the fourth flange are connected by a second fastener.

[0021] Beneficial effects of the present invention:

[0022] The present invention proposes a gas-liquid mixing device for a nuclear power plant, wherein gas and liquid enter a fluid mixing pipe via an air inlet pipe and a liquid inlet pipe, and a first mixing element and a second mixing element arranged in an interlaced manner in the flow passages perform bubble crushing and gas-liquid mixing, so that the gas and liquid are fully contacted and mixed, and the gas (such as hydrogen) is promoted to be dissolved, thereby maintaining or increasing the concentration of dissolved hydrogen in the primary circuit coolant, thereby ensuring the reducing water chemical environment conditions required for the primary circuit, inhibiting the radiation decomposition of water, and reducing the corrosion of primary circuit equipment materials. Compared with the traditional control box hydrogenation method in the RCV system, the use of a gas-liquid mixing device for hydrogenation mixing can eliminate safety hazards such as hydrogen explosion and fire caused by a large amount of hydrogen accumulated in the gas phase of the control box, improve the regulation rate and control accuracy of the hydrogen concentration of the primary circuit coolant, and at the same time avoid the cumbersome replacement of the gas covering type of the control box during startup and shutdown. The gas-liquid mixing device has significant advantages in terms of safety and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0024] Figure 1 is a schematic structural diagram of a gas-liquid mixing device for a nuclear power plant in some embodiments of the present invention;

[0025] Figure 2 yes Figure 1 A partial enlarged view of part A;

[0026] Figure 3is a schematic structural diagram of a gas-liquid mixing device for a nuclear power plant in some other embodiments of the present invention;

[0027] Figure 4 is a curve showing the relationship between the flow rate of the medium and the gas concentration in the fluid mixing pipeline of the present invention;

[0028] The numbers in the drawings indicate as follows: liquid inlet pipeline 1, air inlet pipeline 2, air inlet pipe section 21, curved pipe section 22, air outlet pipe section 23, fluid mixing pipeline 3, first mixing element 31, second mixing element 32, fluid output pipeline 4. DETAILED DESCRIPTION

[0029] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0030] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0031] like Figures 1 to 3As shown, the gas-liquid mixing device of a nuclear power plant in some embodiments of the present invention can be used for hydrogenation and mixing of coolant in a primary circuit of a nuclear power plant. The gas-liquid mixing device comprises: a liquid inlet pipeline 1, an air inlet pipeline 2, a fluid mixing pipeline 3 and a fluid output pipeline 4, wherein the air inlet pipeline 2 is connected to the liquid inlet pipeline 1, and the liquid inlet pipeline 1, the fluid mixing pipeline 3 and the fluid output pipeline 4 are connected in sequence. The air inlet pipeline 2 is passed into a gas or a gas-liquid mixture, and the gas-liquid mixture contains only a small amount of liquid. When the gas-liquid mixing device is used for hydrogenation and mixing of coolant, hydrogen or a small amount of coolant containing hydrogen is passed into the air inlet pipeline 2, and coolant is passed into the liquid inlet pipeline 1. The hydrogen and coolant are fully contacted and mixed in the fluid mixing pipeline 3, and then discharged from the gas-liquid mixing device through the fluid output pipeline 4.

[0032] like Figure 2 As shown, the outlet end of the air inlet pipe 2 extends from the side wall of the liquid inlet pipe 1 into the liquid inlet pipe 1 and extends along the fluid flow direction. Further, the air inlet pipe 2 includes an air inlet pipe section 21, a curved pipe section 22 and an air outlet pipe section 23 connected in sequence, the air inlet pipe section 21 is located outside the liquid inlet pipe 1, and the curved pipe section 22 and the air outlet pipe section 23 are located inside the liquid inlet pipe 1. Preferably, the central axis of the air inlet pipe section 21 and the air outlet pipe section 23 are perpendicular, and the air outlet pipe section 23 is coaxially arranged with the liquid inlet pipe 1. In other embodiments, the air inlet pipe 2 can be inclined to extend into the liquid inlet pipe 1, that is, the angle between the air inlet pipe section 21 of the air inlet pipe 2 and the central axis of the liquid inlet pipe 1 is less than 90 degrees.

[0033] A plurality of mixing elements are arranged in the fluid mixing pipe 3 along its axial direction, and the outer side of the mixing element is in contact with the inner wall of the fluid mixing pipe 3, or there is a small gap between the outer side of the mixing element and the inner wall of the fluid mixing pipe 3. The cross-sectional shape of the mixing element is consistent with the cross-sectional shape of the fluid mixing pipe 3, for example, the cross-sectional shapes of the mixing element and the fluid mixing pipe 3 are both rectangular or circular.

[0034] like Figure 2 As shown, the mixing element may be composed of a plurality of corrugated sheets stacked one by one, and the crests and troughs of the cross sections of adjacent corrugated sheets are connected one by one, and / or adjacent corrugated sheets are connected by connecting sheets, so that a curved and narrow flow channel is formed between adjacent corrugated sheets and between adjacent corrugated sheets and connecting sheets, which has a better effect on breaking bubbles. In some embodiments, adjacent corrugated sheets are connected by connecting sheets, and the mixing unit is composed of a plurality of corrugated sheets and a plurality of connecting sheets alternately stacked, and the corrugated sheets and connecting sheets are stacked so that their projections completely overlap. Under the action of a plurality of mixing elements, the gas is broken into tiny bubbles in the fluid mixing pipe 3, which are fully in contact with the liquid and dissolved into it.

[0035] The corrugated sheet can be formed by repeatedly arranging or sequentially arranging a plurality of corrugated units along the length direction, and the corrugated shape of the corrugated unit is at least one of V-shape, U-shape, Ω-shape, and C-shape. The wavelengths of the plurality of corrugated sheets can be the same or different, and the wavelength here refers to the distance between two adjacent peaks (or troughs) of the cross section of the corrugated sheet. In some embodiments, the mixing element can be an SMV type mixing element (a commercially available product).

[0036] The plurality of mixing elements include at least one first mixing element 31 and at least one second mixing element 32, and the flow channels of the first mixing element 31 and the second mixing element 32 are arranged in an alternating manner. In some embodiments, the shape, structure and size of the first mixing element 31 and the second mixing element 32 are the same, but the arrangement directions of the two in the fluid mixing pipeline 3 are different. Specifically, the plane where the corrugated sheet of the first mixing element 31 is located is perpendicular to the plane where the corrugated sheet of the second mixing element 32 is located, so that the gas and liquid are mixed in two relative vertical and horizontal directions. Preferably, the plane where the corrugated sheet of the first mixing element 31 is located is perpendicular to the horizontal plane (defined as the longitudinal arrangement of the first mixing element 31), and the plane where the corrugated sheet of the second mixing element 32 is located is parallel to the horizontal plane (defined as the transverse arrangement of the second mixing element 32). The first mixing element 31 can not only break the bubbles, but also guide the bubbles to the bottom of the fluid mixing pipeline 3, so that the gas and liquid are mixed more evenly.

[0037] The first mixing element 31 near the inlet end of the fluid mixing pipe 3 is arranged in close contact with the first second mixing element 32, so that after the gas and liquid enter the fluid mixing pipe 3 from the liquid inlet pipe 1, they first pass through the staggered flow channels, so that the bubble crushing and gas-liquid mixing effects are optimal; the remaining mixing elements are arranged at intervals from the adjacent previous mixing elements, so that the mass transfer effect can also be achieved in the pipe section without mixing elements of the fluid mixing pipe 3.

[0038] The effect of the mixing element on the breaking of bubbles is related to the flow rate of the liquid. The greater the flow rate, the greater the impact force between the gas and the mixing element, the smaller the bubbles, and the larger the gas-liquid contact mass transfer area, which is conducive to the dissolution of hydrogen. On the other hand, the greater the flow rate of the liquid, the shorter the time for the gas to pass through the fluid mixing pipeline 3, the shorter the gas-liquid contact mass transfer time, which is not conducive to the dissolution of the gas, and will also increase the pressure difference of the fluid mixing pipeline 3. The relationship curve between the medium flow rate and the gas concentration in the fluid mixing pipeline 3 is shown in Figure 2. Figure 4 As shown, when the medium flow rate is between 0.6 m / s and 1 m / s (0.66 m / s is the optimal flow rate), the fluid mixing pipeline 3 has a better gas-liquid mixing effect, and the pressure difference of the fluid mixing pipeline 3 can also be controlled at an appropriate level.

[0039] The flow rate at the coolant inlet of the primary circuit of the nuclear power plant actually has flow rates corresponding to two working conditions, the corresponding flow rate under normal operating conditions is about 0.66m / s, and the corresponding flow rate under large flow purification conditions is about 1.33m / s. Selecting the medium flow rate in the fluid mixing pipeline 3 to be 0.6m / s to 1m / s can ensure the hydrogenation mixing capacity of the fluid mixing pipeline 3 under normal operating conditions, and at the same time ensure that the pressure difference of the fluid mixing pipeline 3 under large flow purification conditions is within a reasonable range.

[0040] Furthermore, when the flow rate of the medium in the fluid mixing pipe 3 is 0.6 m / s to 1 m / s, if the central axis of the fluid mixing pipe 3 is parallel to the horizontal plane, there is a first spacing L between the remaining mixing elements and the adjacent previous mixing element, and the first spacing L is less than 600 mm. If the first spacing L is further lengthened, the bubbles in the pipe section without the mixing element have basically floated to the top of the inner wall of the fluid mixing pipe 3, and at this time, the mixing element has a small effect on the crushing of the bubbles and can be ignored.

[0041] Specifically, when the central axis of the fluid mixing pipe 3 is parallel to the horizontal plane and the first spacing L is less than 200 mm, Figure 1 As shown, the first first mixing element 31 near the inlet end of the fluid mixing pipe 3 is arranged in close contact with the first second mixing element 32, and the remaining mixing elements include a plurality of first mixing elements 31 and a plurality of second mixing elements 32 that are alternately arranged, thereby ensuring that the gas and liquid are continuously stirred and evenly mixed in both the vertical and horizontal directions, and a more ideal gas-liquid mixing effect can be obtained.

[0042] When the central axis of the fluid mixing pipe 3 is parallel to the horizontal plane and the first spacing L>350mm, Figure 3 As shown, the first first mixing element 31 near the inlet end of the fluid mixing pipeline 3 is arranged in close contact with the first second mixing element 32, and the remaining mixing elements include a plurality of first mixing elements 31. Most of the bubbles in the section of the fluid mixing pipeline 3 without mixing elements after 350 mm have basically floated to the top of the inner wall of the fluid mixing pipeline 3, and the second mixing element 32 arranged transversely thereafter can only act on a small number of bubbles on the top, so the remaining mixing elements are preferably all first mixing elements 31 arranged longitudinally.

[0043] When the central axis of the fluid mixing pipe 3 is parallel to the horizontal plane and 200mm≤first spacing L≤350mm, the first first mixing element 31 and the first second mixing element 32 near the inlet end of the fluid mixing pipe 3 are arranged in close contact, and the remaining mixing elements include a plurality of first mixing elements 31 and a plurality of second mixing elements 32 arranged alternately, or the remaining mixing elements include a plurality of first mixing elements 31. Both arrangements of the remaining mixing elements can obtain a better gas-liquid mixing effect.

[0044] When the flow rate of the medium in the fluid mixing pipe 3 is 0.6m / s to 1m / s, if the central axis of the fluid mixing pipe 3 is perpendicular to the horizontal plane, the first first mixing element 31 near the inlet end of the fluid mixing pipe 3 is arranged in close contact with the first second mixing element 32, and the remaining mixing elements have a second spacing L' between them and the adjacent previous mixing elements, and the second spacing L' is less than 1800mm, and the remaining mixing elements include a plurality of first mixing elements 31 and a plurality of second mixing elements 32 arranged alternately. When the second mixing element 32 is arranged horizontally, the gas with lower density will have the effect of floating and gathering under the action of buoyancy, but when the first mixing element 31 is arranged longitudinally, the flow direction of the gas is the same as the direction of gravity, so the bubbles are not easy to agglomerate, and a better gas-liquid mixing effect can be achieved by the alternating arrangement of the first mixing element 31 and the second mixing element 32.

[0045] Since the pressure difference in the fluid mixing pipe 3 increases linearly and proportionally with the number of mixing elements, the improvement of the gas-liquid mixing effect on the dissolution of gas (such as hydrogen) becomes weaker and weaker with the increase of the number of mixing elements, until it approaches saturation and basically no longer changes with the increase of the number of mixing elements, because the closer the gas is to the saturated solubility, the smaller the concentration difference between the gas and liquid phases, resulting in a decrease in mass transfer efficiency. Therefore, in order to balance the gas-liquid mixing effect and the pressure difference, the total number of mixing elements is preferably 8 to 20, such as 8, 12, 16, 20, etc.

[0046] Several mixing elements are independently fixed in the fluid mixing pipeline 3; or, several mixing elements are pre-connected together by processing and then placed in the fluid mixing pipeline 3, and the processing connection method includes but is not limited to welding, wherein the mixing elements arranged at intervals are connected and fixed by a support member (not shown), and the support member is a support frame, and the support frame is cylindrical or square, and the length direction of the support frame is consistent with the length direction of the fluid mixing pipeline 3, and the length of the support frame can be set according to the spacing between the mixing elements. The end faces of the support frame are in contact with the cross section of the mixing element, and the outer contour of the end face of the support frame is consistent with the outer contour of the cross section of the mixing element. The support frame plays a connecting and supporting role, and does not affect the gas-liquid mixing effect of the pipe section without mixing elements.

[0047] In some embodiments, a plurality of mixing elements are not fixed in the fluid mixing pipe 3, nor are they pre-processed and connected together. The spaced mixing elements are placed in the fluid mixing pipe 3 and are spaced apart by a plurality of support members, which abut between two adjacent mixing elements to facilitate the installation and replacement of the mixing elements and the adjustment of the spacing between the mixing elements. In other embodiments, the two ends of the spaced mixing elements are respectively connected to the support members, that is, a single mixing element and the support members at both ends form an integral structure, and then a plurality of integral structures are placed in the fluid mixing pipe 3, so that the overall stability and support of the mixing elements are better while facilitating installation, and more conducive to the bubble crushing effect.

[0048] Preferably, the central axes of the liquid inlet pipe 1, the fluid mixing pipe 3 and the fluid output pipe 4 coincide, so that the flow path of the fluid in the gas-liquid mixing device is smoother and the structural stability is enhanced. The diameter of the fluid mixing pipe 3 is equal to the diameter of the liquid inlet pipe 1 and the fluid output pipe 4, or the diameter of the fluid mixing pipe 3 is larger or smaller than the diameter of the liquid inlet pipe 1 and the fluid output pipe 4, and the diameter of the liquid inlet pipe 1 and the fluid output pipe 4 does not substantially affect the gas-liquid mixing effect of the fluid mixing pipe 3.

[0049] The fluid mixing pipeline 3 is detachably connected to the liquid inlet pipeline 1 and the fluid outlet pipeline 4, respectively, and the detachable connection is a flange connection, a snap connection or a threaded connection. Figures 1 to 3 As shown, the detachable connection is a flange connection, the inlet end and the outlet end of the fluid mixing pipe 3 are respectively provided with a first flange and a second flange, the outlet end of the liquid inlet pipe 1 is provided with a third flange connected to the first flange, the inlet end of the fluid output pipe 4 is provided with a fourth flange connected to the second flange, the first flange and the third flange are connected by a first fastener, and the second flange and the fourth flange are connected by a second fastener. The first fastener and the second fastener can both include a plurality of flange bolts. Alternatively, the detachable connection is a snap-on connection, the outlet end of the liquid inlet pipe 1 and the inlet end of the fluid output pipe 4 are respectively provided with a groove opening toward the fluid mixing pipe 3, and the two ends of the fluid mixing pipe 3 are respectively provided with a convex edge snapped with the groove, that is, the liquid inlet pipe 1 and the fluid mixing pipe 3, and the fluid mixing pipe 3 and the fluid output pipe 4 are both snapped to form a detachable fixed connection. Alternatively, the detachable connection is a threaded connection, and the inner wall of the outlet end of the liquid inlet pipe 1 and the inner wall of the inlet end of the fluid output pipe 4 are respectively provided with internal threads threadedly connected to the end of the fluid mixing pipe 3, and the outer surfaces of both ends of the fluid mixing pipe 3 are respectively provided with corresponding external threads, that is, a detachable fixed connection is formed between the liquid inlet pipe 1 and the fluid mixing pipe 3, and between the fluid mixing pipe 3 and the fluid output pipe 4 in a threaded manner.

[0050] The present invention proposes a gas-liquid mixing device for a nuclear power plant, wherein gas and liquid enter a fluid mixing pipe 3 via an air inlet pipe 2 and a liquid inlet pipe 1, and a first mixing element 31 and a second mixing element 32 arranged in an alternating manner in the flow channels are used to break bubbles and mix the gas and liquid, so that the gas and liquid are fully contacted and mixed, thereby promoting the dissolution of the gas (such as hydrogen), and then the fluid is discharged via a fluid output pipe 4.

[0051] When the gas-liquid mixing device of the present invention is applied to hydrogenation and mixing of the primary coolant in a nuclear power plant, the gas-liquid mixing device is installed in a chemical and volume control system (RCV) and connected in parallel with a volume control box. The gas-liquid mixing device adds hydrogen to the primary coolant discharged downward, which can gradually increase the dissolved hydrogen concentration in the primary coolant during unit startup and compensate for the normal hydrogen consumption of the reactor coolant system (RCP) during normal operation, thereby meeting the requirements of the primary water chemistry specification for dissolved hydrogen concentration, ensuring the required reducing water chemistry environmental conditions, inhibiting the radiation decomposition of water and reducing the corrosion of primary equipment materials.

[0052] Compared with the traditional control box hydrogenation method, the gas-liquid mixing device of the present invention has the following advantages:

[0053] (1) Since a gas-liquid mixing device is used for hydrogenation mixing, the containment tank does not need to be covered with hydrogen, thereby eliminating safety hazards such as hydrogen explosion and fire caused by a large amount of hydrogen accumulated in the gas phase of the containment tank.

[0054] (2) Compared with the mixing method of indirectly controlling the amount of hydrogenation in the control box by controlling the pressure of the control box, the present invention adopts a gas-liquid mixing device to directly add hydrogen. The gas-liquid mixing device has a very stable effect on the bubble crushing. The amount of hydrogenation can be adjusted by the flow control component of the RCV system, or by adjusting the pressure of the control box. The control is more direct and effective, and the control accuracy of the dissolved hydrogen concentration in the first-loop coolant is higher and the adjustment rate is faster.

[0055] (3) Since the containment box can be covered with nitrogen, the cumbersome replacement of the gas covering type of the containment box during the startup and shutdown phases of the nuclear power plant unit is avoided, that is, there is no need to replace the covering hydrogen with nitrogen and then with air.

[0056] Therefore, the gas-liquid mixing device of the present invention has significant advantages in terms of safety and economy.

[0057] The gas-liquid mixing device of the present invention can actually be extended to apply to gas-liquid mixing process operations of different components in other technical fields.

[0058] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the scope covered by the claims of the present invention.

Claims

1. A gas-liquid mixing device for a nuclear power plant, It is characterized in that include: A liquid inlet pipeline (1), an air inlet pipeline (2), a fluid mixing pipeline (3) and a fluid output pipeline (4); The air inlet pipeline (2) is in communication with the liquid inlet pipeline (1), and the liquid inlet pipeline (1), the fluid mixing pipeline (3) and the fluid output pipeline (4) are in communication with each other in sequence; gas or a gas-liquid mixture is introduced into the air inlet pipeline (2); The fluid mixing pipe (3) is provided with a plurality of mixing elements arranged along its axial direction, the plurality of mixing elements comprising at least one first mixing element (31) and at least one second mixing element (32), and the flow channels of the first mixing element (31) and the second mixing element (32) are arranged in an alternating manner.

2. The gas-liquid mixing device for a nuclear power plant according to claim 1, It is characterized in that The first of the first mixing elements (31) and the first of the second mixing elements (32) close to the inlet end of the fluid mixing pipe (3) are arranged in close contact with each other, and the remaining mixing elements are arranged at intervals from the adjacent previous mixing elements.

3. The gas-liquid mixing device for a nuclear power plant according to claim 1 or 2, It is characterized in that The medium flow rate in the fluid mixing pipeline (3) is 0.6 m / s to 1 m / s. If the central axis of the fluid mixing pipeline (3) is parallel to the horizontal plane, the remaining mixing elements have a first spacing L with the adjacent previous mixing element, and the first spacing L is less than 600 mm. If the central axis of the fluid mixing pipeline (3) is perpendicular to the horizontal plane, the remaining mixing elements have a second spacing L' with the adjacent previous mixing element, and the second spacing L' is less than 1800 mm.

4. The gas-liquid mixing device for a nuclear power plant according to claim 3, It is characterized in that When the central axis of the fluid mixing pipe (3) is parallel to the horizontal plane and the first spacing L is less than 200 mm, the remaining mixing elements include a plurality of the first mixing elements (31) and a plurality of the second mixing elements (32) that are alternately arranged.

5. The gas-liquid mixing device for a nuclear power plant according to claim 3, It is characterized in that When the central axis of the fluid mixing pipe (3) is parallel to the horizontal plane, and the first spacing L>350 mm, the remaining mixing elements include a plurality of the first mixing elements (31).

6. The gas-liquid mixing device for a nuclear power plant according to claim 3, It is characterized in that When the central axis of the fluid mixing pipe (3) is parallel to the horizontal plane, and 200 mm ≤ the first spacing L ≤ 350 mm, the remaining mixing elements include a plurality of the first mixing elements (31) and a plurality of the second mixing elements (32) that are alternately arranged, or the remaining mixing elements include a plurality of the first mixing elements (31).

7. The gas-liquid mixing device for a nuclear power plant according to claim 1, It is characterized in that The mixing element is composed of a plurality of stacked corrugated sheets, the crests and troughs of the cross sections of adjacent corrugated sheets are connected one-to-one, and / or adjacent corrugated sheets are connected via connecting sheets; the plane where the corrugated sheets of the first mixing element (31) are located is perpendicular to the plane where the corrugated sheets of the second mixing element (32) are located.

8. The gas-liquid mixing device for a nuclear power plant according to claim 7, It is characterized in that The plane where the corrugated sheets of the first mixing element (31) are located is perpendicular to the horizontal plane, and the plane where the corrugated sheets of the second mixing element (32) are located is parallel to the horizontal plane.

9. The gas-liquid mixing device for a nuclear power plant according to claim 7, It is characterized in that The corrugated sheet is formed by a plurality of corrugated units which are repeatedly arranged or arranged in sequence along the length direction, and the corrugated shape of the corrugated unit is at least one of V-shape, U-shape, Ω-shape and C-shape.

10. The gas-liquid mixing device for a nuclear power plant according to claim 2, It is characterized in that The mixing elements arranged at intervals are connected and fixed by a support member, and the support member is a support frame, and the support frame is cylindrical or square.

11. The gas-liquid mixing device for a nuclear power plant according to claim 1, It is characterized in that The outlet end of the air inlet pipe (2) extends from the side wall of the liquid inlet pipe (1) into the liquid inlet pipe (1) and extends along the direction of fluid flow.

12. The gas-liquid mixing device for a nuclear power plant according to claim 11, It is characterized in that The air inlet pipe (2) comprises an air inlet pipe section (21), a bent pipe section (22) and an air outlet pipe section (23); the air inlet pipe section (21) is located outside the liquid inlet pipe (1), and the bent pipe section (22) and the air outlet pipe section (23) are located inside the liquid inlet pipe (1); the air inlet pipe section (21) is perpendicular to the central axis of the air outlet pipe section (23), and the air outlet pipe section (23) is coaxially arranged with the liquid inlet pipe (1).

13. The gas-liquid mixing device for a nuclear power plant according to claim 1, It is characterized in that The central axes of the liquid inlet pipeline (1), the fluid mixing pipeline (3) and the fluid output pipeline (4) coincide with each other.

14. The gas-liquid mixing device for a nuclear power plant according to claim 1, It is characterized in that The fluid mixing pipeline (3) is detachably connected to the liquid inlet pipeline (1) and the fluid outlet pipeline (4), respectively, and the detachable connection is a flange connection, a snap connection or a threaded connection.

15. The gas-liquid mixing device for a nuclear power plant according to claim 14, It is characterized in that The detachable connection is a flange connection, the inlet end and the outlet end of the fluid mixing pipeline (3) are respectively provided with a first flange and a second flange, the outlet end of the liquid inlet pipeline (1) is provided with a third flange connected to the first flange, the inlet end of the fluid output pipeline (4) is provided with a fourth flange connected to the second flange, the first flange and the third flange are connected by a first fastener, and the second flange and the fourth flange are connected by a second fastener.

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