Large temperature difference gas mixing, purification, and rectification device

Abstract

The present invention discloses a large temperature difference gas mixing, purification and rectification device, which includes an intake flue, a main cylinder, a reduced-diameter cylinder and an exhaust cylinder. The intake direction of the intake flue is tangent to the main cylinder, and the lower end of the exhaust cylinder extends into the interior of the main cylinder. The intake flue has a wrapped intake flue structure, and the wrapped intake flue structure includes a coaxial central flue and an annular flue. The annular flue is located outside the central flue and wraps the central flue. The central flue is used for introducing flue gas at a first temperature, and the annular flue is used for introducing flue gas at a second temperature. A partition grille is provided at the tail of the exhaust cylinder. This device can take into account the three functions of uniform mixing, purification and rectification. The unique wrapped intake method can avoid the inner wall of the cylinder from being impacted by large thermal stress, thus effectively solving the thermal stress problem caused by the large temperature difference; the partition grille with a dense outer and sparse inner structure can effectively suppress the non-axial velocity of the swirl flow and achieve the purpose of rectification.

Description

Technical Field

[0001] The present invention relates to the technical field of gas mixing devices, and particularly to a gas mixing, purification, and rectification device with a large temperature difference. Background Art

[0002] The molten salt thermal energy storage technology coupled with the traditional coal-fired power generation system can be used to improve the operation flexibility and peak shaving ability of thermal power units.

[0003] When the molten salt thermal energy storage system conducts flue gas molten salt thermal energy storage, the dust-containing flue gas at different temperature zones of the boiler is extracted to the bypass flue, and after mixing, the thermal energy storage is completed through the flue gas-molten salt heat exchanger. The uniformity of the temperature and gas flow velocity of the mixed flue gas is crucial for whether the molten salt undergoes over-temperature decomposition, and the dust concentration of the mixed flue gas affects the erosion and wear degree of the heat exchange tubes. These are all key points to ensure the safe operation of the molten salt.

[0004] Mixers can be divided into dynamic mixers and static mixers according to different hybrid powers. The dynamic mixer relies on a mechanical power unit to force the fluid to flow to achieve a uniform mixing effect. The static mixer, on the other hand, increases the velocity gradient of the fluid's laminar flow or forms turbulence by the fluid impacting various types of plate elements. It has no mechanical rotating parts, is simple in structure, small in volume, and high in efficiency, and has been widely used.

[0005] These mixers can all ensure the uniform mixing of the mixed gas to a certain extent. However, when simultaneously achieving the rapid mixing, purification, and rectification of two airflows, practical engineering problems such as dust accumulation, wear, and blockage caused by the dust-containing gas will be faced. Especially when the temperature difference between the two gases is large, there is a large thermal stress impact on the mixer, which will all affect the stability and safety of the device operation. Summary of the Invention

[0006] The purpose of the present invention is to provide a gas mixing, purification, and rectification device with a large temperature difference. This device can take into account the functions of uniform mixing and pre-dust removal, and can simultaneously achieve efficient mixing, purification, and rectification, and solve the thermal stress problem brought by the large temperature difference.

[0007] To achieve the above purpose, the present invention provides a gas mixing, purification, and rectification device with a large temperature difference, including an intake flue, a main cylinder, a reduced-diameter cylinder, and an exhaust cylinder. The reduced-diameter cylinder is located below the main cylinder. The intake direction of the intake flue is tangent to the main cylinder. The exhaust cylinder is coaxially arranged with the main cylinder, and its lower end penetrates the upper end surface of the main cylinder and extends into the interior of the main cylinder. The intake flue has a wrapped intake flue structure, and the wrapped intake flue structure includes a coaxial central flue and an annular flue. The annular flue is located outside the central flue and wraps the central flue. The central flue is used to introduce the flue gas at the first temperature, and the annular flue is used to introduce the flue gas at the second temperature.

[0008] Optionally, the temperature of the second-temperature flue gas is higher than that of the first-temperature flue gas.

[0009] Optionally, the wrapped intake flue duct structure includes a first intake flue duct and a second intake flue duct; the first intake flue duct is inserted into the second intake flue duct from the side wall, bends and changes direction, and then coincides with or is parallel to the axis of the second intake flue duct. The interior of the first intake flue duct forms the central flue, and the gap between the first intake flue duct and the second intake flue duct in the circumferential direction forms the annular flue.

[0010] Optionally, the cross-section of the central flue is circular, and the cross-section of the annular flue is annular; alternatively, the cross-section of the central flue is rectangular, and the cross-section of the annular flue is in a shape like a Chinese character 'hui'.

[0011] Optionally, a partition rectification grid is provided inside the exhaust cylinder or on the exhaust path.

[0012] Optionally, the mesh holes of the partition rectification grid gradually decrease from the inside to the outside.

[0013] Optionally, the mesh holes of the partition rectification grid are divided into a central area and at least one annular area. The mesh density of the central area is the smallest, and the mesh density of each annular area increases layer by layer from the inside to the outside.

[0014] Optionally, the exhaust cylinder is connected to a heat exchanger through an exhaust pipe. The partition rectification grid is provided at the intake end of the heat exchanger and covers the flue gas flow area of the heat exchanger.

[0015] Optionally, the reduced-diameter cylinder is in the shape of a cone with a diameter gradually decreasing from top to bottom, and its outer edge line is a straight line, a concave arc, or a convex arc.

[0016] Optionally, a dust removal integrated device is provided at the bottom of the reduced-diameter cylinder. Its dust discharge port enters the buffer hopper after passing through a straight dropping section and is further connected to the ash conveying system.

[0017] Optionally, the intake flue, the main cylinder, and the reduced-diameter cylinder are provided with an anti-abrasion layer, an inner heat insulation layer, and / or an outer heat insulation layer.

[0018] The large temperature difference gas mixing, purification, and rectification device provided by the present invention has a wrapped intake flue structure. During operation, two flue gases can enter the main cylinder coaxially in a form where one wraps the other and perform a swirling motion. After reaching the bottom of the variable-diameter cylinder, they continue to move spirally upward, fully mix, and then flow out from the outlet of the exhaust cylinder. During this process, the particles carried by the flue gas are thrown towards the wall by the centrifugal force and discharged from the bottom of the variable-diameter cylinder under the action of gravity. This device takes into account both the functions of uniform mixing and purification based on the swirling flow field structure. Its unique wrapped intake method can avoid the inner wall of the cylinder from being subjected to a large thermal stress impact, thus effectively solving the thermal stress problem caused by the large temperature difference. Moreover, the structure is simple and compact, and it can be used as a mixer, ash remover, cyclone, and a device with multiple functions.

[0019] In a preferred embodiment, a partition rectification grid is provided inside the exhaust cylinder or on the exhaust path to achieve the swirling rectification function, thereby effectively suppressing the radial velocity of the flue gas and making the overall flow relatively more uniform. Brief Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of the first large temperature difference gas mixing, purification, and rectification device provided by the embodiment of the present invention;

[0021] Figure 2 It is a schematic structural diagram of the partition rectification grid;

[0022] Figure 3 It is a schematic structural diagram of the second large temperature difference gas mixing, purification, and rectification device provided by the embodiment of the present invention;

[0023] Figure 4 It is a schematic structural diagram of the connection between the third large temperature difference gas mixing, purification, and rectification device provided by the embodiment of the present invention and a heat exchanger;

[0024] Figure 5 It is a schematic diagram of the structure formed by the mutual cooperation of the first intake flue pipeline and the second intake flue pipeline to form a wrapped intake flue structure;

[0025] Figure 6 It is a schematic D-D cross-sectional diagram of the partition rectification grid;

[0026] Figure 7 It is a distribution diagram of the temperature gradient of the outermost fluid inside the mixer corresponding to the inlet structure with parallel intake under the basic working condition;

[0027] Figure 8 It is a distribution diagram of the temperature gradient of the outermost fluid inside the mixer corresponding to the inlet structure with medium temperature wrapping low temperature under the basic working condition;

[0028] Figure 9Schematic diagram of the cross-sectional position of the mixer corresponding to the inlet structure where medium temperature wraps low temperature under the basic working condition;

[0029] Figure 10 For Figure 9 Velocity distribution diagrams at the cross-sectional positions of A-A, B-B, and C-C in

[0030] Figure 11 For Figure 9 Temperature distribution diagrams at the cross-sectional positions of A-A and B-B in

[0031] Figure 12 Radial velocity distribution diagrams of the gas flow at the outlet of the mixer with or without the three-zone grid rectification under the basic working condition.

[0032] In the figure:

[0033] 10. Main cylinder body 20. Reducing cylinder body 30. Inlet flue 31. Central flue 32. Annular flue 33. First inlet flue pipeline 34. Second inlet flue pipeline 40. Exhaust cylinder body 50. Partition rectification grid 60. Exhaust pipeline 70. Heat exchanger Specific implementation manners

[0034] To enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0035] In this article, terms such as "upper, lower, inner, outer" are established based on the positional relationship shown in the accompanying drawings. Depending on the different accompanying drawings, the corresponding positional relationship may also change accordingly. Therefore, it cannot be understood as an absolute limitation on the protection scope; moreover, relational terms such as "first" and "second" are only used to distinguish one component with the same name from another, and do not necessarily require or imply any such actual relationship or order between these components.

[0036] Please refer to Figure 1 、 Figure 2 , Figure 1 Structural schematic diagram of the first large temperature difference gas mixing, purification, and rectification device provided by the embodiment of the present invention; Figure 2 Structural schematic diagram of the first partition rectification grid.

[0037] As shown in the figure, in a specific embodiment, the large temperature difference gas mixing, purification, and rectification device provided by the present invention mainly consists of a main cylinder body 10, a reducing cylinder body 20, an inlet flue 30, an exhaust cylinder body 40, and other parts.

[0038] Specifically, the main cylinder body 10 is generally cylindrical. The variable-diameter cylinder body 20 is located below the main cylinder body 10. The variable-diameter cylinder body 20 is in the shape of a cone with a diameter gradually decreasing from top to bottom, and its outer edge line is an inwardly concave arc, meeting the requirement for dust to fall. The outer diameter of the main cylinder body 10 is about 5.8 m, and the overall height is about 14 m. The main cylinder body 10 and the variable-diameter cylinder body 20 are provided with an anti-wear layer, an inner insulation layer, and / or an outer insulation layer (not shown in the figure), which can be realized by providing multiple layers such as an inner insulation layer, an anti-wear layer, and an outer insulation layer. The thickness and type of the selected material are not limited and are selected according to specific conditions. For example, the main cylinder body 10 and the variable-diameter cylinder body 20 are made of carbon steel bodies, and a double-layer inner lining is provided inside, which are anti-wear castable and thermal insulation materials from the inside to the outside respectively.

[0039] The intake flue 30 is connected to the main cylinder body 10 in a tangential manner, and its intake direction is tangent to the inner wall of the main cylinder body 10. The diameter of the exhaust cylinder body 40 is smaller than that of the main cylinder body 10. The exhaust cylinder body 40 is coaxially arranged with the main cylinder body 10, and its lower end penetrates through the upper end surface of the main cylinder body 10 and extends into the main cylinder body 10 for a certain distance.

[0040] The intake flue 30 is a wrapped intake flue structure. This wrapped intake flue structure has a coaxial central flue 31 and an annular flue 32. The cross-section of the central flue 31 is rectangular, and the cross-section of the annular flue 32 is in the shape of a Chinese character 'hui'. The annular flue 32 is located outside the central flue 31 and wraps the central flue 31. The central flue 31 is used to introduce the first-temperature flue gas, such as low-temperature flue gas, and the annular flue 32 is used to introduce the second-temperature flue gas, such as medium-temperature flue gas. That is to say, the temperature of the second-temperature flue gas is higher than that of the first-temperature flue gas. In this embodiment, the temperature difference between the low-temperature flue gas and the medium-temperature flue gas is about 300 °C.

[0041] During actual operation, the low-temperature flue gas and the medium-temperature flue gas can enter the main cylinder body 10 coaxially from the intake flue 30 in the form of the medium-temperature flue gas wrapping the low-temperature flue gas to perform a swirling motion, continue to move spirally upward after reaching the bottom of the variable-diameter cylinder body 20, and flow out from the outlet of the exhaust cylinder body 40 after being fully mixed. The particles carried by the flue gas are thrown towards the wall surface under the action of centrifugal force and are discharged from the bottom of the variable-diameter cylinder body 20 under the action of gravity. A dust removal integrated device is provided at the bottom of the variable-diameter cylinder body 20, and its dust discharge port enters the buffer hopper after the material dropping straight section and is further connected to the ash conveying system.

[0042] Due to the adoption of the unique intake method of the medium-temperature flue gas wrapping the low-temperature flue gas, the present invention can take into account both the functions of uniform mixing and purification, avoid the inner wall of the cylinder being subjected to a large thermal stress impact, and thus effectively solve the thermal stress problem caused by a large temperature difference.

[0043] In addition, a partition rectifying grid 50 is also provided inside the exhaust cylinder body 40, and the mesh holes of the partition rectifying grid 50 gradually decrease from the inside to the outside.

[0044] In this embodiment, the mesh holes of the partition rectification grid 50 are divided into a central area and two annular areas. The mesh density of the central area is the smallest, and the mesh densities of the first and second annular areas increase layer by layer from the inside to the outside.

[0045] By arranging the partition rectification grid 50 inside the exhaust cylinder body 40, the swirl rectification function can be realized, thereby effectively suppressing the radial velocity of the flue gas and making it relatively more uniform overall.

[0046] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of the second large-temperature-difference gas mixing, purification, and rectification device provided by the embodiment of the present invention.

[0047] As shown in the figure, compared with the first embodiment, the difference in this embodiment is that the variable-diameter cylinder body 20 is in the shape of a cone with a diameter gradually decreasing from top to bottom, and its outer edge line is an outwardly convex arc.

[0048] In this embodiment, the same parts as those in the first embodiment are given the same reference numerals, and the same text descriptions are omitted.

[0049] Please continue to refer to Figure 4 , Figure 5 , Figure 6 , Figure 4 which is a schematic structural diagram of the connection between the third large-temperature-difference gas mixing, purification, and rectification device provided by the embodiment of the present invention and the heat exchanger; Figure 5 is a schematic diagram of the structure of the wrapped intake flue formed by the cooperation of the first intake flue pipeline and the second intake flue pipeline; Figure 6 is a schematic cross-sectional view of the second partition rectification grid.

[0050] As shown in the figure, compared with the first embodiment, the difference in this embodiment is that the variable-diameter cylinder body 20 is in the shape of a cone with a diameter gradually decreasing from top to bottom, and its outer edge line is a straight line.

[0051] Moreover, the exhaust cylinder body 40 is connected to the heat exchanger 70 through the exhaust pipe 60. Two streams of medium and low-temperature flue gases need to enter the mixing device for sufficient mixing and pre-dust removal to provide uniform boundary conditions for the inlet of the heat exchanger 70. In order to obtain better heat exchange effects, a partition rectification grid 50 covering the flue gas flow area of the heat exchanger can be provided at the intake end of the heat exchanger 70.

[0052] The mesh holes of the partition rectification grid 50 are divided into a central area and two annular areas. The mesh density of the central area is the smallest, and the mesh densities of the first and second annular areas increase layer by layer from the inside to the outside.

[0053] If the central region is named as Region 1, the first annular region and the second annular region are named as Region 2 and Region 3 respectively, then the width of Region 1 is 2L, the widths of Region 2 and Region 3 are L, and the width of each mesh in Region 2 is D x , and the length is D y , the width of each mesh in Region 3 is d x , and the length is d y , D x >d x and D y >d y , in this embodiment, D x =D y , d x =d y , D x is approximately twice that of d x , D y is approximately twice that of d y .

[0054] In order to form a wrapped intake flue structure, this embodiment is provided with a first intake flue pipeline 33 and a second intake flue pipeline 34.

[0055] The first intake flue pipeline 33 is inserted into the second intake flue pipeline 34 from the upper side wall and bends and deflects to coincide (or be parallel) with the axis of the second intake flue pipeline 34. In this way, a central flue 31 is formed inside the first intake flue pipeline 33, and the gap between the first intake flue pipeline 33 and the second intake flue pipeline 34 in the circumferential direction forms an annular flue 32.

[0056] Please refer to Figure 7 and Figure 8 , Figure 7 , for the temperature gradient distribution diagram of the outermost fluid inside the mixer corresponding to the inlet structure with parallel intake under the basic condition; Figure 8 , for the temperature gradient distribution diagram of the outermost fluid inside the mixer corresponding to the inlet structure with medium-temperature wrapping low-temperature under the basic condition.

[0057] As shown in the figure, under the basic condition, the temperatures of the two medium-low temperature flue gases are 646 °C and 339 °C respectively, and the total flue gas flow rate is 2.67×10 4 kg / h, and the proportion of the medium-temperature flue gas is about 68%.

[0058] Based on the principle that the flow velocities of the medium-low temperature flue gases in the inlet section are the same, two flue gas inlet structures are designed, namely parallel intake and medium-temperature wrapping low-temperature intake.

[0059] The relative situation of the thermal stress received by the inner wall of the mixer is indirectly measured by obtaining the fluid temperature change near the wall surface.

[0060] It can be seen that the temperature gradient is the largest at the bottom of the tangency position between the rectangular flue and the cylinder. For this, the axial temperature gradient of the wall-attached airflow is small under the medium-temperature wrapping and low-temperature intake mode, indicating that this intake mode can effectively reduce the thermal stress impact.

[0061] Please continue to refer to Figures 9 to 12 , Figure 9 which is a schematic diagram of the sectional position of the mixer corresponding to the inlet structure of medium-temperature wrapping and low-temperature under the basic condition; Figure 10 is Figure 9 the velocity distribution diagrams at the sectional positions of A-A, B-B, and C-C in Figure 11 is Figure 9 the temperature distribution diagrams at the sectional positions of A-A and B-B in

[0062] As shown in the figure, under the basic condition, for the A-A axial section and the B-B and C-C transverse sections, the overall velocity of the flue gas presents a composite eddy flow distribution, which theoretically satisfies the mixing of the two flue gases and the separation of the soot.

[0063] By locally magnifying the flow field near the exhaust cylinder in the A-A section, it is found that only a very small amount of fluid flows into the exhaust cylinder from the side, meaning that most of the airflow will flow out of the inner cylinder after a complete swirling process.

[0064] The flue gas outlet temperature in the B-B section of the corresponding temperature field is also very uniform. Under this condition, the overall pressure drop is obtained as 774 Pa, and the maximum temperature difference at the outlet section is 4.4 °C.

[0065] Please refer to Figure 12 , Figure 12 which is the radial velocity distribution diagram of the airflow at the outlet of the mixer with or without a three-zone grid rectifier under the basic condition.

[0066] As shown in the figure, select the section D-D near the inlet of the heat exchanger 70. The red part represents the radial velocity distribution state without the grid, and the blue part represents the radial velocity distribution state after setting the three-zone rectifying grid. It can be found that without the three-zone rectifying grid, the radial velocity of the mixed airflow has many wave peaks and wave valleys with large amplitudes, showing large fluctuations. After passing through the three-zone rectifying grid, the number and amplitude of the wave peaks and wave valleys are greatly reduced, the radial velocity of the airflow is significantly reduced, and the overall is relatively more uniform, creating better boundary conditions for the heat exchanger to exchange heat.

[0067] The above embodiments are only the preferred solutions of the present invention, and are not specifically limited thereto. On this basis, targeted adjustments can be made according to actual needs to obtain different implementation manners. For example, the cross-section of the central flue is circular, and the cross-section of the annular flue is circular, etc. Since there are many possible implementation manners, they will not be exemplified one by one here.

[0068] Compared with the prior art, the present invention has at least the following advantages:

[0069] (1) Compact structure and integrated functions: One device can simultaneously meet the triple functions of energy substance exchange, purification and rectification, with a simple structure and a compact layout.

[0070] (2) Wide application range: It is applicable to the mixing of different or the same gases such as dusty flue gas, clean flue gas, and gas; it is applicable to the mixing of two gases with a large temperature difference, so the temperature range of the two gas flows can be selected widely.

[0071] (3) High stability and safety: The device itself is provided with abrasion prevention and heat preservation, and combined with the wrapped air inlet structure, the thermal stress impact is greatly reduced, and it runs stably and has high safety.

[0072] (4) It can provide uniform boundary conditions for downstream devices and ensure the safety of the operation of downstream devices in some cases.

[0073] The device for mixing, purifying and rectifying gases with a large temperature difference provided by the present invention has been introduced in detail above. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A large temperature difference gas mixing, purifying and rectifying device, comprising an air intake flue (30), a main cylinder (10), a diameter-changing cylinder (20) and an exhaust cylinder (40), wherein the diameter-changing cylinder (20) is located below the main cylinder (10), the air intake direction of the air intake flue (30) is tangent to the main cylinder (10), the exhaust cylinder (40) is coaxially arranged with the main cylinder (10), and the lower end thereof penetrates through the upper end surface of the main cylinder (10) and extends into the interior of the main cylinder (10), characterized in that: The air intake flue (30) has a wrapped air intake flue structure, the wrapped air intake flue structure comprising a coaxial central flue (31) and an annular flue (32), the annular flue (32) being located outside the central flue (31) and wrapping the central flue (31), the central flue (31) being used to introduce flue gas of a first temperature, and the annular flue (32) being used to introduce flue gas of a second temperature.

2. The large temperature difference gas mixing, purification and rectification device according to claim 1, characterized in that: The temperature of the second-temperature flue gas is greater than the temperature of the first-temperature flue gas.

3. The large temperature difference gas mixing, purification and rectification device according to claim 1, characterized in that: The wrapped air intake flue structure comprises a first air intake flue pipe (33) and a second air intake flue pipe (34); the first air intake flue pipe (33) is inserted into the second air intake flue pipe (34) and, after bending and changing direction, coincides with or is parallel to the axis of the second air intake flue pipe (34); the interior of the first air intake flue pipe (33) forms the central flue (31); and the gap between the first air intake flue pipe (33) and the second air intake flue pipe (34) in the circumferential direction forms the annular flue (32).

4. The large temperature difference gas mixing, purification and rectification device according to claim 3 is characterized in that: The cross section of the central flue (31) is circular, and the cross section of the annular flue (32) is circular; or, the cross section of the central flue (31) is rectangular, and the cross section of the annular flue (32) is U-shaped.

5. The large temperature difference gas mixing, purification and rectification device according to claim 1, characterized in that: A partitioned rectifying grid (50) is provided inside the exhaust cylinder (40) or on the exhaust path.

6. The large temperature difference gas mixing, purification and rectification device according to claim 5, characterized in that: The mesh size of the partitioned rectifying grid (50) gradually decreases from the inside to the outside.

7. The large temperature difference gas mixing, purification and rectification device according to claim 6, characterized in that: The mesh of the partitioned rectifying grid (50) is divided into a central area and at least one layer of annular area, the mesh density of the central area is the smallest, and the mesh density of each layer of the annular area increases layer by layer from the inside to the outside.

8. The large temperature difference gas mixing, purification and rectification device according to claim 7, characterized in that: The exhaust cylinder (40) is connected to a heat exchanger (70) via an exhaust pipeline (60), and the partitioned rectifying grid (50) is arranged at an air inlet end of the heat exchanger (70) and covers a flue gas flow area of ​​the heat exchanger (70).

9. The large temperature difference gas mixing, purification and rectification device according to claim 1, characterized in that: The variable diameter cylinder (20) is in the shape of a cone with a diameter that gradually decreases from top to bottom, and its outer edge line is a straight line, an inwardly concave arc, or an outwardly convex arc.

10. The large temperature difference gas mixing, purification and rectification device according to claim 8, characterized in that: An integrated ash discharge device is provided at the bottom of the variable diameter cylinder (20), and its ash discharge port enters the buffer hopper after passing through the straight section of the falling material, and is further connected to the ash conveying system; the air inlet flue (30), the main cylinder (10) and the variable diameter cylinder (20) are provided with an anti-wear layer, an inner thermal insulation layer and / or an outer thermal insulation layer.

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