Gas-liquid mixing apparatus for nuclear power plant

Abstract

A gas-liquid mixing apparatus for a nuclear power plant, comprising: a liquid inlet pipe (1), a gas inlet pipe (2), a fluid mixing pipe (3), and a fluid output pipe (4). The gas inlet pipe (2) is communicated with the liquid inlet pipe (1); the liquid inlet pipe (1), the fluid mixing pipe (3) and the fluid output pipe (4) are sequentially communicated; a gas or a gas-liquid mixture is introduced into the gas inlet pipe (2); a plurality of mixing elements are arranged inside the fluid mixing pipe (3) in the axial direction thereof; the plurality of mixing elements include at least one first mixing element (31) and at least one second mixing element (32); and flow channels of the first mixing element (31) are staggered with respect to flow channels of the second mixing element (32). The first mixing element (31) and second mixing element (32), in the fluid mixing pipe (3), having respective flow channels staggered with respect to each other perform foam crushing and gas-liquid stirring and mixing, to implement full gas-liquid contact and mixing and promote gas (for example, hydrogen) dissolution, thereby keeping or increasing the dissolved hydrogen concentration in a primary circuit coolant.

Description

Nuclear power plant gas-liquid mixing device TECHNICAL FIELD

[0001] The present application relates to the technical field of gas-liquid mixing, in particular to a nuclear power plant gas-liquid mixing device. BACKGROUND

[0002] At present, during the normal operation of a pressurized water reactor nuclear power plant, a certain primary coolant dissolved hydrogen concentration is generally maintained to ensure the primary reducing water chemical environment condition, therefore, hydrogen must be continuously added to the primary liquid coolant, that is, gas-liquid mixing operation is performed. The traditional coolant hydrogenation method in the chemical and volume control system (RCV) of the pressurized water reactor nuclear power plant is as follows: the discharged primary coolant is sprayed from the nozzle at the top of the volume control tank, the mist-shaped coolant fully contacts with the hydrogen gas in the gas phase in the volume control tank, so that the hydrogen gas is fully dissolved into the coolant, thereby completing the hydrogenation of the coolant. However, the hydrogenation method has the following defects: 1) the volume control tank uses hydrogen gas covering, a large amount of hydrogen gas is accumulated in the gas phase, and there is a safety risk of hydrogen explosion and fire; 2) the hydrogenation amount required for adjusting or maintaining the hydrogen concentration of the primary coolant is completed by adjusting or controlling the gas phase pressure of the volume control tank, which can only slowly adjust the dissolved hydrogen concentration of the primary coolant, and the time consumption is long and the adjustment precision is not high; 3) the type of gas covering in the volume control tank needs to be replaced during the startup and shutdown of the unit, that is, the hydrogen gas is replaced by nitrogen gas, and then the nitrogen gas is replaced by air. SUMMARY

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

[0004] The technical solution adopted by the present application to solve the technical problem is: a nuclear power plant gas-liquid mixing device, comprising: a liquid inlet pipeline, a gas inlet pipeline, a fluid mixing pipeline and a fluid outlet pipeline.

[0005] The gas inlet pipeline is in communication with the liquid inlet pipeline, and the liquid inlet pipeline, the fluid mixing pipeline and the fluid outlet pipeline are in communication in sequence; the gas inlet pipeline introduces gas or gas-liquid mixture.

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

[0007] In some embodiments, the first first mixing element and the first second mixing element are arranged in close contact near the inlet end of the fluid mixing pipeline, and the remaining mixing elements are arranged in spaced relationship with the adjacent previous mixing element.

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

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

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

[0011] In some embodiments, when the central axis of the fluid mixing pipeline is parallel to the horizontal plane, and 200mm≤the first spacing L≤350mm, the remaining mixing elements include a plurality of first mixing elements and a plurality of second mixing elements arranged alternately, 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 corrugated sheets stacked together, the wave crests and wave 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 in which the corrugated sheets of the first mixing element are located is perpendicular to the plane in which the corrugated sheets of the second mixing element are located.

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

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

[0015] In some embodiments, the mixing elements arranged at intervals are connected and fixed by a support, and the support is a support frame in the shape of a cylinder or a square body.

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

[0017] In some embodiments, the gas inlet pipe comprises a gas inlet pipe section, a curved pipe section and a gas outlet pipe section, the gas inlet pipe section is located outside the liquid inlet pipe, and the curved pipe section and the gas outlet pipe section are located inside the liquid inlet pipe; the central axis of the gas inlet pipe section is perpendicular to the central axis of the gas outlet pipe section, and the gas 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 outlet pipe coincide.

[0019] In some embodiments, the fluid mixing pipe is detachably connected with the liquid inlet pipe and the fluid outlet pipe respectively, and the detachable connection is a flange connection, a buckle 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 with the first flange, the inlet end of the fluid outlet pipe is provided with a fourth flange connected with the second flange, the first flange and the third flange are connected through a first fastener, and the second flange and the fourth flange are connected through a second fastener.

[0021] The present application has the following beneficial effects:

[0022] The present application provides a gas-liquid mixing device for a nuclear power plant. Gases and liquids enter a fluid mixing pipe through a gas inlet pipe and a liquid inlet pipe. First and second mixing elements with staggered flow channels are arranged to break bubbles and mix the gases and liquids, so that the gases and liquids are fully mixed and the gases (such as hydrogen) are dissolved, thereby maintaining or increasing the dissolved hydrogen concentration in the primary coolant, ensuring the required reducing water chemical environment condition of the primary loop, inhibiting the irradiation decomposition of water and reducing the corrosion of the primary loop equipment materials. Compared with the traditional container control box hydrogenation method in the RCV system, the gas-liquid mixing device for hydrogenation mixing can eliminate the safety hazards of hydrogen explosion and fire caused by the accumulation of a large amount of hydrogen gas in the container control box, improve the adjustment rate and control accuracy of the hydrogen concentration of the primary coolant, and avoid the cumbersome replacement of the gas covering types of the container control box during startup and shutdown. The gas-liquid mixing device has significant advantages in safety and economy. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application will be further described below with reference to the drawings and embodiments. In the drawings:

[0024] FIG. 1 is a structural schematic view of a gas-liquid mixing device for a nuclear power plant in some embodiments of the present application;

[0025] FIG. 2 is a partial enlarged view of part A in FIG. 1;

[0026] FIG. 3 is a structural schematic view of a gas-liquid mixing device for a nuclear power plant in some other embodiments of the present application;

[0027] Fig. 4 is a curve of the relationship between the medium flow rate in the fluid mixing pipeline and the gas concentration of the present application;

[0028] The reference signs in the drawings represent the following: liquid inlet pipeline 1, gas inlet pipeline 2, gas inlet pipeline section 21, curved pipeline section 22, gas outlet pipeline section 23, fluid mixing pipeline 3, first mixing element 31, second mixing element 32, fluid outlet pipeline 4. DETAILED DESCRIPTION

[0029] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application will be described in detail with reference to the drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "upper", "lower", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like are based on the directions or positional relationships shown in the drawings, constructed and operated in a particular direction, and are only for the convenience of describing the technical solutions, and cannot be understood as indicating that the devices or elements indicated must have a particular direction, therefore, it cannot be understood as a limitation on the present application.

[0030] It should also be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing", "setting" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. When an element is referred to as "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there can be one or more intervening elements. The terms "first", "second", "third" and the like are only for the convenience of describing the technical solutions, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features, therefore, the features with "first", "second", "third" and the like can explicitly or implicitly include one or more of the features. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] As shown in FIGS. 1-3, the gas-liquid mixing device in some embodiments of the present application can be used for hydrogen mixing with coolant in a primary loop of a nuclear power plant. The gas-liquid mixing device includes a liquid inlet pipe 1, a gas inlet pipe 2, a fluid mixing pipe 3 and a fluid outlet pipe 4. The gas inlet pipe 2 is in communication with the liquid inlet pipe 1, and the liquid inlet pipe 1, the fluid mixing pipe 3 and the fluid outlet pipe 4 are in communication in sequence. The gas inlet pipe 2 is connected to a gas or a gas-liquid mixture containing a small amount of liquid. When the gas-liquid mixing device is used for hydrogen mixing with coolant, the gas inlet pipe 2 is connected to hydrogen or a small amount of coolant containing hydrogen, the liquid inlet pipe 1 is connected to coolant, and the hydrogen and the coolant are fully contacted and mixed in the fluid mixing pipe 3, and then discharged from the gas-liquid mixing device through the fluid outlet pipe 4.

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

[0033] The fluid mixing pipe 3 is provided with a plurality of mixing elements arranged along the axial direction thereof. The outer side of the mixing element is attached to 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, such as both the mixing element and the fluid mixing pipe 3 being rectangular or circular in cross-sectional shape.

[0034] As shown in FIG. 2, the mixing element can be composed of a plurality of corrugated sheets stacked together. The wave crests and wave troughs of the cross sections of adjacent corrugated sheets are connected one-to-one, and / or adjacent corrugated sheets are connected by connecting sheets, so that curved and narrow flow channels are formed between adjacent corrugated sheets and between adjacent corrugated sheets and connecting sheets, which have a good effect on the breaking of gas bubbles. In some embodiments, adjacent corrugated sheets are connected by connecting sheets, and the mixing element is composed of a plurality of corrugated sheets and a plurality of connecting sheets stacked alternately. The stacking of the corrugated sheets and the connecting sheets makes their projections completely overlap. Under the action of a plurality of mixing elements, the gas is broken into fine bubbles in the fluid mixing pipe 3, fully contacts with the liquid and dissolves into the liquid.

[0035] The corrugated sheets can be repeatedly arranged or sequentially arranged in the length direction by a plurality of corrugated units, and the corrugated units have at least one of V-shaped, U-shaped, omega-shaped and C-shaped corrugated shapes. The wavelengths of the plurality of corrugated sheets can be the same or different. Here, the wavelength refers to the distance between two adjacent wave crests (or wave 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 alternately. In some embodiments, the first mixing element 31 and the second mixing element 32 have the same shape structure and size, but the arrangement directions of the two in the fluid mixing pipeline 3 are different. Specifically, the plane in which the corrugated sheets of the first mixing element 31 are located is perpendicular to the plane in which the corrugated sheets of the second mixing element 32 are located, so that the gas-liquid is mixed in opposite longitudinal and transverse directions. Preferably, the plane in which the corrugated sheets of the first mixing element 31 are located is perpendicular to the horizontal plane (defined as the first mixing element 31 is arranged longitudinally), and the plane in which the corrugated sheets of the second mixing element 32 are located is parallel to the horizontal plane (defined as the second mixing element 32 is arranged transversely). The first mixing element 31 not only can break the bubbles, but also can guide the bubbles to the bottom of the fluid mixing pipeline 3, so that the gas-liquid mixing is more uniform.

[0037] The first mixing element 31 and the first mixing element 32 are arranged close to the inlet end of the fluid mixing pipeline 3, so that after the gas and the liquid enter the fluid mixing pipeline 3 from the liquid inlet pipeline 1, they first pass through the alternately arranged flow channels, so that the bubble breaking and gas-liquid stirring effects are optimal. The remaining mixing elements are arranged at intervals with the adjacent previous mixing element, so that the mass transfer effect can also be achieved in the mixing element-free pipe section of the fluid mixing pipeline 3.

[0038] The bubble breaking effect of the mixing element is related to the flow rate of the liquid. The greater the flow rate, the greater the impact force of the gas on the mixing element, the smaller the bubble, and the greater the gas-liquid contact mass transfer area, which is beneficial 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, and the shorter the gas-liquid contact mass transfer time, which is not conducive to the dissolution of the gas, and at the same time, it also causes the increase of the pressure difference of the fluid mixing pipeline 3. The relationship curve between the medium flow rate in the fluid mixing pipeline 3 and the gas concentration is shown in FIG. 4. When the medium flow rate is 0.6 m / s~1 m / s (0.66 m / s is the optimal flow rate), the fluid mixing pipeline 3 has a good gas-liquid mixing effect, and the pressure difference of the fluid mixing pipeline 3 can also be controlled at a suitable level.

[0039] The flow rate at the inlet of the primary coolant of the nuclear power plant actually has two corresponding flow rates, about 0.66 m / s in the normal operation condition and about 1.33 m / s in the large flow rate purification condition. The medium flow rate in the fluid mixing pipe 3 is selected as 0.6 m / s-1 m / s, which can ensure the hydrogen mixing capacity of the fluid mixing pipe 3 in the normal operation condition and ensure that the pressure difference of the fluid mixing pipe 3 is in a reasonable range in the large flow rate purification condition.

[0040] Further, in the case that the medium flow rate in the fluid mixing pipe 3 is 0.6 m / s-1 m / s, if the central axis of the fluid mixing pipe 3 is parallel to the horizontal plane, the first spacing L between the remaining mixing elements and the adjacent previous mixing element is less than 600 mm. If the first spacing L is further lengthened, the bubbles in the pipe section without mixing elements have basically floated to the top of the inner wall of the fluid mixing pipe 3, at which time the breaking effect of the mixing elements on the bubbles is small 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, as shown in FIG. 1, the first first mixing element 31 close to 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 arranged alternately, so as to ensure that the gas-liquid is continuously stirred and mixed uniformly in the longitudinal and transverse 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 is greater than 350 mm, as shown in FIG. 3, the first first mixing element 31 close to 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. Most of the bubbles in the pipe section without mixing elements of the fluid mixing pipe 3 after 350 mm have basically floated to the top of the inner wall of the fluid mixing pipe 3, and the second mixing element 32 arranged transversely after that can only act on a small amount of top bubbles, 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 the first spacing L is greater than 350 mm, as shown in FIG. 3, the first first mixing element 31 close to 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. Most of the bubbles in the pipe section without mixing elements of the fluid mixing pipe 3 after 350 mm have basically floated to the top of the inner wall of the fluid mixing pipe 3, and the second mixing element 32 arranged transversely after that can only act on a small amount of top bubbles, so the remaining mixing elements are preferably all first mixing elements 31 arranged longitudinally.

[0044] When the medium flow rate in the fluid mixing pipeline 3 is 0.6 m / s to 1 m / s, the central axis of the fluid mixing pipeline 3 is perpendicular to the horizontal plane, the first first mixing element 31 close to the inlet end of the fluid mixing pipeline 3 is arranged in abutment with the first second mixing element 32, the second spacing L' between the remaining mixing elements and the adjacent previous mixing element is less than 1800 mm, 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 transversely, 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 gather, and better gas-liquid mixing effect can be achieved by alternately arranging the first mixing element 31 and the second mixing element 32.

[0045] Since the pressure difference in the fluid mixing pipeline 3 increases linearly and proportionally with the number of mixing elements, and the improvement of the gas-liquid mixing effect on the gas (such as hydrogen) dissolution effect 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 saturation solubility, the smaller the concentration difference between the gas-liquid two 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] The plurality of mixing elements are independently fixed in the fluid mixing pipeline 3; or the plurality of mixing elements are connected together in advance by processing, and then placed in the fluid mixing pipeline 3, and the processing connection mode includes but is not limited to welding, wherein the mixing elements arranged at intervals are connected and fixed by a support (not shown), the support is a support frame, the support frame is in the shape of a cylinder or a square body, 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 abut against the cross sections of the mixing elements, 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, the mixing elements are not fixed in the fluid mixing pipe 3, nor are they connected together by machining in advance. The spaced mixing elements are placed in the fluid mixing pipe 3 and are spaced by the supports abutting between two adjacent mixing elements, facilitating 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 connected with the supports respectively, that is, the single mixing element and the supports at its two ends form an integral structure, and then the integral structures are placed in the fluid mixing pipe 3, so that the installation is facilitated, the overall stability and supportability of the mixing elements are better, and the bubble breaking effect is more favorable.

[0048] Preferably, the central axes of the liquid inlet pipe 1, the fluid mixing pipe 3 and the fluid outlet 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 pipe diameter of the fluid mixing pipe 3 is equal to the pipe diameters of the liquid inlet pipe 1 and the fluid outlet pipe 4, or the pipe diameter of the fluid mixing pipe 3 is greater than or less than the pipe diameters of the liquid inlet pipe 1 and the fluid outlet pipe 4, and the pipe diameters of the liquid inlet pipe 1 and the fluid outlet pipe 4 basically do not affect the gas-liquid mixing effect of the fluid mixing pipe 3.

[0049] The fluid mixing pipe 3 is detachably connected with the liquid inlet pipe 1 and the fluid outlet pipe 4, which can be flange connection, buckle connection or threaded connection. For example, as shown in FIGS. 1-3, the detachable connection is 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 with the first flange, the inlet end of the fluid outlet pipe 4 is provided with a fourth flange connected with 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 each include a plurality of flange bolts. Alternatively, the detachable connection is buckle connection, the outlet end of the liquid inlet pipe 1 and the inlet end of the fluid outlet pipe 4 are respectively provided with a groove with an opening facing the fluid mixing pipe 3, and the two ends of the fluid mixing pipe 3 are respectively provided with a convex edge buckled 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 outlet pipe 4 are detachably connected in the form of buckling. Alternatively, the detachable connection is threaded connection, the inner walls of the outlet end of the liquid inlet pipe 1 and the inlet end of the fluid outlet pipe 4 are respectively provided with an internal thread for screwing with the end of the fluid mixing pipe 3, and the outer surfaces of the two ends of the fluid mixing pipe 3 are respectively provided with corresponding external threads, that is, the liquid inlet pipe 1 and the fluid mixing pipe 3, and the fluid mixing pipe 3 and the fluid outlet pipe 4 are detachably connected in the form of screwing.

[0050] The present application provides a kind of nuclear power plant gas-liquid mixing device, gas and liquid enter fluid mixing pipe 3 via inlet pipe 2 and inlet pipe 1, flow channel staggered first mixing element 31 and second mixing element 32 are arranged, bubble breaking and gas-liquid stirring are carried out, so that gas and liquid are fully contacted and mixed, promote gas (such as hydrogen) dissolution, then fluid is discharged via fluid output pipe 4.

[0051] The gas-liquid mixing device of the present application is applied to the hydrogenation mixing of the primary coolant of a nuclear power plant. The gas-liquid mixing device is installed in the chemical and volume control system (RCV) and is connected in parallel with the volume control tank. The gas-liquid mixing device adds hydrogen into the downwardly leaking primary coolant, gradually increases the dissolved hydrogen concentration in the primary coolant during the startup of the unit, and compensates for the normal hydrogen consumption of the reactor coolant system (RCP) during normal operation, thereby meeting the requirements of the dissolved hydrogen concentration in the water chemistry specification of the primary loop, ensuring the required reducing water chemistry environment, inhibiting the irradiation decomposition of water, and reducing the corrosion of the materials of the primary loop equipment.

[0052] Compared with the conventional hydrogenation method of the volume control tank, the gas-liquid mixing device of the present application has the following advantages:

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

[0054] (2) Compared with the mixing method of indirectly controlling the hydrogenation amount in the volume control tank by controlling the pressure of the volume control tank, the gas-liquid mixing device of the present application directly hydrogenates. The gas-liquid mixing device has a very stable bubble breaking effect, and the hydrogenation amount can be adjusted by the flow control component of the RCV system or by adjusting the pressure of the volume control tank to control the hydrogenation amount. The control is more direct and effective, and the control precision of the dissolved hydrogen concentration in the primary coolant is higher and the adjustment rate is faster.

[0055] (3) Since the volume control tank can be covered with nitrogen, the cumbersome replacement of the types of gas cover in the volume control tank during the startup and shutdown of the unit of the nuclear power plant is avoided, i.e., the cover hydrogen is not replaced with nitrogen, and then replaced with air.

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

[0057] The gas-liquid mixing device of the present application can also be practically applied to the gas-liquid mixing process operation of different components in other technical fields.

[0058] It can be understood that the above embodiments only express the preferred embodiments of the present application, which are described more specifically and in detail, but cannot be understood as a limitation to the patent scope of the present application; it should be pointed out that the above technical features can be freely combined without departing from the concept of the present application for those skilled in the art, and several modifications and improvements can be made, which all belong to the protection scope of the present application; therefore, any equivalent transformation and modification made to the patent claim scope of the present application shall belong to the coverage of the patent claim of the present application.

Claims

1. A gas-liquid mixing device for a nuclear power plant, characterized by comprising: include: Liquid inlet pipe (1), air inlet pipe (2), fluid mixing pipe (3) and fluid outlet pipe (4); The air inlet pipe (2) is connected to the liquid inlet pipe (1), and the liquid inlet pipe (1), the fluid mixing pipe (3) and the fluid output pipe (4) are connected in sequence; the air inlet pipe (2) is used to introduce gas or a gas-liquid mixture; The fluid mixing pipe (3) is provided with a plurality of mixing elements arranged along its axial direction. 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 staggered.

2. The nuclear power plant gas-liquid mixing device according to claim 1, characterized by The first first mixing element (31) near the inlet end of the fluid mixing pipe (3) is fitted with the first second mixing element (32), and the remaining mixing elements are spaced apart from the adjacent previous mixing element.

3. The nuclear power plant gas-liquid mixing device according to claim 1 or 2, characterized by, The medium velocity in the fluid mixing pipe (3) is 0.6m / s to 1m / s. If the central axis of the fluid mixing pipe (3) is parallel to the horizontal plane, the other mixing elements have a first distance L between them and the adjacent mixing element, and the first distance L is less than 600mm. If the central axis of the fluid mixing pipe (3) is perpendicular to the horizontal plane, the other mixing elements have a second distance L' between them and the adjacent mixing element, and the second distance L' is less than 1800mm.

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

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

6. The nuclear power plant gas-liquid mixing device of claim 3, wherein, When the central axis of the fluid mixing pipe (3) is parallel to the horizontal plane and 200mm≤first spacing L≤350mm, 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).

7. The nuclear power plant gas-liquid mixing device of claim 1, wherein, The hybrid element is composed of several corrugated sheets stacked together, with the crests and troughs of the cross sections of adjacent corrugated sheets connected one-to-one, and / or adjacent corrugated sheets connected by connecting pieces; the plane where the corrugated sheet of the first hybrid element (31) is located is perpendicular to the plane where the corrugated sheet of the second hybrid element (32) is located.

8. The nuclear power plant gas-liquid mixing device of claim 7, wherein, The plane where the corrugated sheet of the first mixing element (31) is located is perpendicular to the horizontal plane, and the plane where the corrugated sheet of the second mixing element (32) is located is parallel to the horizontal plane.

9. The nuclear power plant gas-liquid mixing device of claim 7, wherein, The corrugated sheet is formed by repeatedly arranging or sequentially arranging several 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.

10. The nuclear power plant gas-liquid mixing device of claim 2, wherein, The mixing elements arranged at intervals are connected and fixed by supports, which are support frames in cylindrical or square body shape.

11. The nuclear power plant gas-liquid mixing device of claim 1, wherein, The outlet end of the air inlet pipe (2) extends into the liquid inlet pipe (1) from the side wall of the liquid inlet pipe (1) and extends along the fluid flow direction.

12. The nuclear power plant gas-liquid mixing device of claim 11, wherein, The air inlet pipe (2) comprises an air inlet pipe section (21), a curved pipe section (22) and an air outlet pipe section (23), the air inlet pipe section (21) is located outside the liquid inlet pipe (1), the curved pipe section (22) and the air outlet pipe section (23) are located inside the liquid inlet pipe (1); 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).

13. The nuclear power plant gas-liquid mixing device of claim 1, wherein, The central axes of the liquid inlet pipe (1), the fluid mixing pipe (3) and the fluid outlet pipe (4) coincide.

14. The nuclear power plant gas-liquid mixing device of claim 1, wherein, The fluid mixing pipe (3) is detachably connected with the liquid inlet pipe (1) and the fluid outlet pipe (4), and the detachable connection is flange connection, buckle connection or screw connection.

15. The nuclear power plant gas-liquid mixing device of claim 14, wherein, The detachable connection is flange connection, the inlet end and the outlet end of the fluid mixing pipe (3) are respectively provided with first flange and second flange, the outlet end of the liquid inlet pipe (1) is provided with third flange connected with the first flange, the inlet end of the fluid outlet pipe (4) is provided with fourth flange connected with the second flange, the first flange and the third flange are connected by first fastener, and the second flange and the fourth flange are connected by second fastener.

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