Fluidized bed heat exchanger and method suitable for ultrafine particles

Abstract

The application discloses a fluidized bed heat exchanger and method suitable for superfine particles, and relates to the technical fields of chemical reactors and particle heat exchangers. The fluidized bed heat exchanger comprises a shell, heat exchange pipes, a flow guide cylinder, a rectifier plate and a gas distributor. The shell is internally provided with a feeding area, a particle ordered circular flow area and a particle disordered circular flow area in sequence along the direction of gravity. The heat exchange pipes are arranged in the shell at intervals. The flow guide cylinder is arranged in the particle ordered circular flow area, a central flow guide area is formed in the flow guide cylinder, and an annular gap flow guide area is formed between the flow guide cylinder and the shell. The gas distributor is arranged in the particle disordered circular flow area, and the gas distributor can divide the particle disordered circular flow area into a first disordered circular flow area located below the central flow guide area and a second disordered circular flow area located below the annular gap flow guide area. The entering particles can perform internal circulation movement between the central flow guide area and the annular gap flow guide area along the flow guide cylinder under the difference between the gas velocities of the first disordered circular flow area and the second disordered circular flow area, so that the heat transfer coefficient in the shell is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical reactors and particle heat exchangers, and more particularly to a fluidized bed heat exchanger and method suitable for ultrafine particles. Background Technology

[0002] In the fields of energy, chemical engineering, and pharmaceuticals, there are numerous processes that require maintaining reaction temperatures. To improve reaction efficiency, ultrafine particles with small density and particle size, which are easy to adhere to the reactor surface and readily agglomerate, are typically used as reaction raw materials. However, existing heat exchangers struggle to meet the heat transfer and temperature control requirements of these ultrafine particles.

[0003] Therefore, there is an urgent need to develop a fluidized bed heat exchanger suitable for ultrafine particles to meet the heat transfer and temperature control requirements of ultrafine particles, thereby improving reaction conversion rate, target product quality and yield. Summary of the Invention

[0004] The purpose of this invention is to provide a fluidized bed heat exchanger and method suitable for ultrafine particles, solving the problem that existing heat exchangers cannot meet the heat transfer and temperature control requirements of ultrafine particles with small density and particle size, which are prone to wall deposition and agglomeration.

[0005] The above-mentioned objectives of the present invention can be achieved by the following technical solutions:

[0006] This invention provides a fluidized bed heat exchanger suitable for ultrafine particles, comprising:

[0007] The shell has an inlet, an outlet and an outlet. The inlet is inclined upward and has an inlet pipe. The inside of the shell is arranged in sequence along the direction of gravity, including an inlet zone, an ordered particle circulation zone and a disordered particle circulation zone.

[0008] Heat exchange tubes are inserted at intervals inside the housing;

[0009] A flow guide tube is disposed in the ordered particle circulation zone, which divides the ordered particle circulation zone into a central flow guide zone and an annular gap flow guide zone. The central flow guide zone is located inside the flow guide tube, and the annular gap flow guide zone is located between the flow guide tube and the shell.

[0010] A rectifier plate is disposed below the feed inlet, which can collect particles entering the feed area from the feed pipe and direct them to the central guide area;

[0011] A gas distributor is disposed in the particle disordered circulation region. The gas distributor can divide the particle disordered circulation region into a first disordered circulation region and a second disordered circulation region. The first disordered circulation region is located below the central guide region, and the second disordered circulation region is located below the annular gap guide region.

[0012] Particles entering from the feed inlet can circulate internally between the central guide zone and the annular guide zone along the guide tube under the velocity difference between the first disordered circulation zone and the second disordered circulation zone.

[0013] In one specific embodiment, the air velocity in the first disordered circulation zone is greater than that in the second disordered circulation zone, the circulation path direction of the particles in the central guide zone is opposite to the direction of gravity, and the circulation path direction of the particles in the annular gap guide zone is the same as the direction of gravity.

[0014] In one specific embodiment, the gas distributor is a dual gas distributor, which includes a central gas distributor and a sidewall gas distributor. The central gas distributor and the sidewall gas distributor are arranged parallel to each other below the heat exchange tube. Along the direction of gravity, the projected outline of the guide tube is located between the projected outline of the central gas distributor and the projected outline of the sidewall gas distributor.

[0015] In one specific embodiment, the angle between the extension direction of the rectifier plate and the direction of gravity is 120° to 165°.

[0016] In one specific embodiment, the rectifier plate is provided with a plurality of flow guide baffles at intervals parallel to the extension direction of the rectifier plate, or the rectifier plate is provided with a plurality of flow guide grooves at intervals parallel to the extension direction of the rectifier plate.

[0017] In one specific embodiment, the central flow guiding zone is provided with a vertically arranged first heat exchange tube, and the annular flow guiding zone is provided with a horizontally or vertically arranged second heat exchange tube.

[0018] In one specific embodiment, the first heat exchange tube is a shell-and-tube heat exchange tube or a heat pipe heat exchange tube, and the second heat exchange tube is a heat pipe heat exchange tube or a coil heat exchange tube.

[0019] In one specific embodiment, the surface structure of the first heat exchange tube and the second heat exchange tube is one of finned tube, studded tube, and smooth tube.

[0020] In one specific embodiment, the guide tube has a constant diameter section and a variable diameter section, the constant diameter section is located above the variable diameter section, and the diameter of the variable diameter section is enlarged along the direction of gravity.

[0021] In one specific embodiment, the ordered particle circulation region is provided with an annular gas distributor, which is disposed in the annular flow guiding region.

[0022] The present invention also provides a fluidized bed heat exchange method suitable for ultrafine particles, the method being applicable to the fluidized bed heat exchanger for ultrafine particles as described above, comprising the following steps:

[0023] Turn on the heat transfer medium supply to the heat exchange tube and introduce the heat transfer medium into the heat exchange tube;

[0024] Turn on the gas distributor and introduce fluidizing gas into the particle disorder circulation zone;

[0025] Turn on the feed pipe to introduce a gas-solid mixture into the feed zone;

[0026] Adjusting the gas velocity ratio of the gas distributor causes the particles to circulate internally along the guide tube. After heat exchange with the hot particles, the heat transfer medium undergoes a phase change and flows into the steam drum through the heat exchange tube.

[0027] The features and advantages of this invention are:

[0028] 1. The fluidized bed heat exchanger for ultrafine particles provided by this invention divides the ordered particle circulation zone inside the shell into a central guiding zone and an annular guiding zone by setting a guide tube, and divides the disordered particle circulation zone into a first disordered circulation zone and a second disordered circulation zone corresponding to the central guiding zone and the annular guiding zone, respectively, by setting a gas distributor. By adjusting the gas flow rate of the gas distributor, the gas velocity difference between the first disordered circulation zone and the second disordered circulation zone can be controlled, so that the particles can carry out ordered internal circulation motion and disordered internal circulation motion in the ordered particle circulation zone and the disordered particle circulation zone, respectively. This increases the flow velocity of the particles on the wall surface, reduces the adhesion of particles to the wall surface, and at the same time increases the renewal rate of particles on the heat exchange tube surface, thereby improving the overall heat transfer coefficient and reaction efficiency.

[0029] 2. The fluidized bed heat exchange method for ultrafine particles provided by this invention controls the heat transfer coefficient and reaction efficiency during the internal circulation of particles by adjusting the gas velocity ratio of the gas distributor, thus enabling the fluidized bed heat exchanger to also function as a temperature-controlled reactor. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A schematic diagram of the structure of the fluidized bed heat exchanger for ultrafine particles provided by the present invention, in which a sleeve-type heat exchange tube is vertically arranged inside the shell;

[0032] Figure 2 This is a schematic diagram of the structure of a fluidized bed heat exchanger suitable for ultrafine particles provided by the present invention, in which heat pipe heat exchange tubes are vertically arranged inside the shell.

[0033] Figure 3 This is a schematic diagram of the structure of the fluidized bed heat exchanger for ultrafine particles provided by the present invention, in which a second heat exchange tube is horizontally arranged in the annular guide zone;

[0034] Figure 4 A schematic diagram of the structure of the fluidized bed heat exchanger for ultrafine particles provided by the present invention, in which a second heat exchange tube is vertically arranged in the annular flow guiding region;

[0035] Figure 5 A schematic diagram of a single-section rectifier plate with guide grooves provided for a fluidized bed heat exchanger suitable for ultrafine particles, as provided by the present invention;

[0036] Figure 6 A schematic diagram of a single-section rectifier plate with a flow guide baffle provided for a fluidized bed heat exchanger suitable for ultrafine particles, as provided by the present invention;

[0037] Figure 7 This is a schematic diagram of the structure of the multi-segment rectifier plate of the fluidized bed heat exchanger suitable for ultrafine particles provided by the present invention;

[0038] Figure 8 A schematic diagram of the structure of the two-section guide tube of the fluidized bed heat exchanger for ultrafine particles provided by the present invention, in which guide holes are provided in both the constant diameter section and the variable diameter section;

[0039] Figure 9 The schematic diagram of the two-section guide tube of the fluidized bed heat exchanger for ultrafine particles provided by the present invention is shown, with guide holes provided in the constant diameter section and guide plates provided in the variable diameter section.

[0040] Figure 10 The schematic diagram shows the structure of a two-section guide tube with circular guide holes in the variable diameter section of the fluidized bed heat exchanger for ultrafine particles provided by the present invention.

[0041] Explanation of icon numbers:

[0042] 1. Shell; 11. Inlet; 12. Exhaust port; 13. Outlet; 14. Inlet pipe; 15. Inlet zone; 16. Ordered particle circulation zone; 161. Central guide zone; 162. Annular guide zone; 17. Disordered particle circulation zone; 171. First disordered circulation zone; 172. Second disordered circulation zone; 18. Variable diameter section;

[0043] 2. Heat exchange tube; 21. First heat exchange tube; 22. Second heat exchange tube;

[0044] 3. Flow guide tube; 31. Flow guide hole; 32. Flow guide plate; 33. Constant diameter section; 34. Variable diameter section;

[0045] 4. Rectifier plate; 41. Baffle plate; 42. Flow channel;

[0046] 5. Gas distributor; 51. Central gas distributor; 52. Sidewall gas distributor;

[0047] 6. Annular gas distributor. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] like Figures 1 to 4As shown, this invention provides a fluidized bed heat exchanger suitable for ultrafine particles, comprising: a shell 1, which has an inlet 11, an exhaust port 12, and an outlet 13, the exhaust port 12 and the outlet 13 being respectively located at the upper and lower ends of the shell 1; an inlet pipe 14 for supplying a gas-solid mixture into the shell 1 on the inlet 11; the inlet pipe 14 is inclined upward at the inlet 11 to facilitate the smooth entry of particles; and an adjustable valve is provided on the inlet pipe 14 to facilitate the adjustment of the fluidized bed heat exchanger according to the particle size distribution. The amount of particles fed in is controlled by heat demand. Inside the shell 1, along the direction of gravity, there are sequentially arranged a feeding zone 15, an ordered particle circulation zone 16, and a disordered particle circulation zone 17. Heat exchange tubes 2 are inserted circumferentially within the shell 1, each having a cavity to accommodate the heat transfer medium. The portion of the heat exchange tubes 2 placed in the disordered particle circulation zone 17 forms a concentrated heat exchange tube section. A guide tube 3 is located in the ordered particle circulation zone 16, dividing it into a central guide zone 1. 61 and annular guide zone 162, a central guide zone 161 is formed inside the guide tube 3, and an annular space between the outer side of the guide tube 3 and the inner wall of the shell 1 forms the annular guide zone 162; rectifier plate 4, located below the feed inlet 11, can collect particles entering the feed zone 15 from the feed pipe 14 and direct them to the central guide zone 161, avoiding the impact of particles scouring the tube wall of the heat exchange tube 2 and thus affecting the service life of the fluidized bed heat exchanger; gas distributor 5, located in the disordered particle circulation zone 17, gas The distributor 5 divides the disordered particle circulation zone 17 into a first disordered circulation zone 171 and a second disordered circulation zone 172. The first disordered circulation zone 171 is located below the central guide zone 161, and the second disordered circulation zone 172 is located below the annular gap guide zone 162. Particles entering from the feed inlet 11 can circulate internally between the central guide zone 161 and the annular gap guide zone 162 along the guide tube 3, based on the velocity difference between the first disordered circulation zone 171 and the second disordered circulation zone 172. In this embodiment, the heat exchange tube 2 adopts a finned tube structure and is fixedly connected to the shell 1 by welding. The guide tube 3 overlaps on the fins of the heat exchange tube 2. The gas distributor 5 is welded to the shell 1 by a bracket. Of course, the heat exchange tube 2 can also adopt other structural forms. Similarly, the above components can also be connected and positioned using other connection methods. This invention does not limit this.

[0050] Specifically, when there is no gas velocity difference between the first disordered circulation zone 171 and the second disordered circulation zone 172 of the particle disordered circulation zone 17, the particles entering from the feed inlet 11 move downwards under the action of gravity to above the central guide zone 161. There, they begin to experience upward resistance from the gas in the particle disordered circulation zone 17, causing them to decelerate and move downwards into the central guide zone 161. As the distance between the particles and the gas distributor 5 decreases, the upward resistance on the particles continuously increases. When the upward resistance exceeds gravity, the particles enter a fluidized state and begin to move upwards. As the distance between the particles and the gas distributor 5 increases, the upward resistance on the particles continuously decreases, and the particles decelerate... The particles move upwards, leaving the central guide zone 161 and spreading outwards, flowing into the annular guide zone 162. When the upward resistance experienced by the particles is less than gravity, the particles begin to move downwards and enter the second disordered circulation zone 172. Under the influence of the gas velocity difference between the first and second disordered circulation zones 171 and 172, the particles undergo disordered internal circulation along the multiple heat exchange tubes 2 inserted at intervals between the first and second disordered circulation zones 171 and 172. Simultaneously, under the influence of the gas velocity of the gas distributor 5, the particles move upwards to the ordered circulation zone 16 and undergo ordered internal circulation along the guide tube 3 between the central guide zone 161 and the annular guide zone 162. By adjusting the gas flow rate of the gas distributor 5 in the first and second disordered circulation zones 171 and 172 respectively, the gas velocity difference between the first and second disordered circulation zones 171 and 172 is controlled, thereby enhancing the heat transfer between the ordered and disordered circulation zones.

[0051] Among them, such as Figures 1 to 4 As shown, in order to ensure the amount of particles to undergo internal circulation, the shell 1 is provided with a variable diameter section 18 in the particle disorder circulation zone 17. The diameter of the variable diameter section 18 is reduced along the direction of gravity, and a gas distributor 5 is provided at the starting point of the variable diameter section 18.

[0052] Among them, such as Figures 1 to 4 As shown, the guide tube 3 can adopt a single-section straight cylindrical structure or a two-section structure with a straight upper section and a conical lower section. Preferably, when the amount of particles in the internal circulation is large, the guide tube 3 adopts a single-section structure; when the amount of particles in the internal circulation is small, the guide tube 3 adopts a two-section structure. Further details can be found in the reference section. Figures 8 to 10 As shown, to avoid particle accumulation, bridging, and local dead zones during internal circulation, a single-section flow guide tube 3 can have multiple flow guide holes 31 spaced apart on its wall; a two-section flow guide tube 3 can have multiple flow guide holes 31 spaced apart on its upper straight cylindrical wall and multiple flow guide holes 31 or multiple flow guide plates 32 spaced apart on its lower conical cylindrical wall. In this embodiment, the upper straight cylindrical diameter of the flow guide tube 3 is consistent with the circumferential distribution radius of the heat exchange tube 2.

[0053] like Figure 8 As shown, the two-section structure of the guide tube 3 can be provided with multiple guide holes 31 at intervals on both the upper straight cylindrical wall and the lower conical cylindrical wall to avoid particle accumulation, bridging, and local dead zones during internal circulation; as Figure 9 As shown, the two-section structure guide tube 3 can also have multiple guide holes 31 spaced apart on the upper straight cylindrical wall and multiple guide plates 32 spaced apart on the lower conical cylindrical wall to avoid particle accumulation, bridging and local dead zones during internal circulation.

[0054] The shape of the guide hole 31 can be circular, rectangular, or triangular, etc., preferably, such as Figure 10 As shown, multiple circular guide holes 31 are spaced apart on the lower conical cylinder wall. The opening ratio of the guide holes 31 gradually increases from top to bottom, ranging from 5% to 50%, in order to enhance the circulation of particles through the openings and thus enhance the heat transfer effect.

[0055] The fluidized bed heat exchanger for ultrafine particles provided by this invention divides the ordered particle circulation zone 16 inside the shell 1 into a central guiding zone 161 and an annular guiding zone 162 by setting a guide tube 3, and divides the disordered particle circulation zone 17 into a first disordered circulation zone 171 and a second disordered circulation zone 172 corresponding to the central guiding zone 161 and the annular guiding zone 162, respectively, by setting a gas distributor 5. By adjusting the gas flow rate of the gas distributor 5, the gas velocity difference between the first disordered circulation zone 171 and the second disordered circulation zone 172 is controlled, so that the particles can undergo ordered internal circulation motion and disordered internal circulation motion in the ordered particle circulation zone 16 and the disordered particle circulation zone 17, respectively. This increases the flow velocity of the particles on the wall surface, reduces the adhesion of the particles to the wall surface, and at the same time increases the renewal rate of the particles on the surface of the heat exchange tube 2, thereby improving the overall heat transfer coefficient and reaction efficiency.

[0056] According to one embodiment of the present invention, the gas velocity in the first disordered circulation region 171 is greater than the gas velocity in the second disordered circulation region 172, the circulation path direction of the particles in the central guide region 161 is opposite to the direction of gravity, and the circulation path direction of the particles in the annular gap guide region 162 is the same as the direction of gravity. Specifically, after the particles collected by the rectifier plate 4 flow towards the central guide zone 161, they move downwards to above the central guide zone 161. Due to the upward resistance of the gas in the first disordered circulation zone 171, the particles decelerate and move downwards into the central guide zone 161. When the upward resistance is greater than gravity, the particles enter a fluidized state and begin to move upwards, leaving the central guide zone 161. They then diffuse circumferentially from the upper end of the guide tube 3 into the annular guide zone 162. The gravity of the particles entering the annular guide zone 162 is greater than the upward gas resistance, causing them to move downwards into the second disordered circulation zone 172. Under the influence of the velocity difference between the first and second disordered circulation zones 171 and 172, the particles move downwards through the gas distributor 5 and... In the gaps between the disordered circulation zones 17 and the lower region of the heat exchange tube 2, particles flow from the second disordered circulation zone 172 to the first disordered circulation zone 171. While moving upwards due to the upward resistance of the gas in the first disordered circulation zone 171, the particles also flow towards the second disordered circulation zone 172. Under the continuous influence of the gas velocity difference between the first and second disordered circulation zones 171 and 172, the particles undergo disordered internal circulation along the heat exchange tube 2 between the first and second disordered circulation zones 171 and 172. Simultaneously, under the action of the gas velocity in the gas distributor 5, the particles move upwards to the ordered circulation zone 16 and undergo ordered internal circulation along the guide tube 3 between the central guide zone 161 and the annular guide zone 162. The circulation path direction of the ordered internal circulation of the particles is as follows: Figure 1 and Figure 2 As shown by the light-colored arrows, the cyclic path direction of the particles' disordered internal circulation motion is as follows: Figure 1 and Figure 2 As indicated by the dark arrow in the middle.

[0057] According to one embodiment of the present invention, the gas distributor 5 is a dual gas distributor 5, which includes a central gas distributor 51 and a sidewall gas distributor 52. The central gas distributor 51 and the sidewall gas distributor 52 are arranged parallel to each other below the heat exchange tube 2. Along the direction of gravity, the projected outline of the guide tube 3 is located between the projected outline of the central gas distributor 51 and the projected outline of the sidewall gas distributor 52. Specifically, as shown... Figures 1 to 4As shown, the particle disordered circulation zone 17 is divided into a first disordered circulation zone 171 centered on the center and a second disordered circulation zone 172 surrounding the center, by a central gas distributor 51 and a sidewall gas distributor 52 respectively located below the central guide zone 161 and the annular guide zone 162. To maximize the amount of particles undergoing internal circulation, the central gas distributor 51 is located at the beginning of the diameter change of the variable diameter section 18 below the sidewall gas distributor 52.

[0058] According to one embodiment of the present invention, the angle between the extending direction of the rectifier plate 4 and the direction of gravity is 120° to 165°. Specifically, as shown... Figures 1 to 4 As shown, the angle between the extension direction of the rectifier plate 4 and the direction of gravity is 120° to 165°, in order to prevent particles from accumulating on the rectifier plate 4 while slowing down the falling velocity of the particles, thus achieving full fluidization of the particles. (See also...) Figures 5 to 7 As shown, the rectifier plate 4 can be configured as a single section or multiple sections depending on the internal space of the housing 1. The specific structure of the rectifier plate 4 can be a flat plate, an arc-shaped plate, etc. Preferably, the rectifier plate 4 adopts an arc-shaped plate structure. In order to obtain a better particle diversion effect, the radius of curvature of the arc-shaped plate structure is between the tube radius of the feed pipe 14 and the circumferential distribution radius of the heat exchange tube 2.

[0059] like Figure 5 and Figure 6 As shown, according to one embodiment of the present invention, a plurality of flow guide baffles 41 parallel to the extending direction of the flow guide plate 4 are spaced apart on the flow guide plate 4, or a plurality of flow guide grooves 42 parallel to the extending direction of the flow guide plate 4 are spaced apart on the flow guide plate 4, so as to uniformly guide the incoming particles to the central flow guide area 161. Specifically, to ensure that the particles flow smoothly and uniformly into the central flow guide area, the distance between two adjacent flow guide baffles 41 is greater than the particle diameter, and the flow guide baffles 41 are located at the rear of the flow guide plate 4; the width of the flow guide grooves 42 is greater than the particle diameter, and the flow guide grooves 42 are located at the rear of the flow guide plate 4.

[0060] According to one embodiment of the present invention, the central flow guiding region 161 is provided with a vertically arranged first heat exchange tube 21, and the annular flow guiding region 162 is provided with a horizontally or vertically arranged second heat exchange tube 22. Specifically, as shown... Figure 3 and Figure 4 As shown, heat exchange tubes are provided both inside and outside the guide tube 3. The central guide zone 161 formed inside the guide tube 3 is provided with a vertically arranged first heat exchange tube 21, and the annular guide zone 162 formed between the outside of the guide tube 3 and the shell 1 is provided with a horizontally or vertically arranged second heat exchange tube 22. By increasing the number of heat exchange tubes arranged inside the shell 1, the heat transfer efficiency is improved.

[0061] Furthermore, the first heat exchange tube 21 is a shell-and-tube heat exchange tube or a heat pipe heat exchange tube, and the second heat exchange tube 22 is a heat pipe heat exchange tube or a coil heat exchange tube.

[0062] According to a preferred embodiment of the present invention, the surface structure of the first heat exchange tube 21 and the second heat exchange tube 22 is one of finned tube, stud tube and smooth tube.

[0063] According to one embodiment of the present invention, the guide tube 3 has a constant-diameter section 33 and a variable-diameter section 34, the constant-diameter section 33 being disposed above the variable-diameter section 34, and the diameter of the variable-diameter section 34 being increased along the direction of gravity. Specifically, as shown... Figure 1 , Figure 2 , Figures 8 to 10 As shown, the guide tube 3, which adopts a two-section structure, has a constant-diameter section 33 and a variable-diameter section 34. The constant-diameter section 33 is formed in the upper straight cylindrical part of the guide tube 3, and the variable-diameter section 34 is formed in the lower conical part of the guide tube 3. The distance between the variable-diameter section 34 and the shell 1 is 1 / 5 to 1 / 30 of the diameter of the shell 1. In this embodiment, the constant-diameter section 33 and the variable-diameter section 34 of the guide tube 3 are fixedly connected by welding or overlapping.

[0064] According to one embodiment of the present invention, the particle-ordered circulation region 16 is provided with an annular gas distributor 6, which is disposed in the annular guide region 162. Specifically, as shown... Figure 1 and Figure 2 As shown, the annular gap guide zone 162 is provided with an annular gap gas distributor 6 to facilitate gas replenishment in the annular gap guide zone 162 and maintain the fluidization state of the particles in the annular gap guide zone 162. Preferably, the annular gap gas distributor 6 is provided at the connection between the constant diameter section 33 and the variable diameter section 34 of the guide cylinder 3.

[0065] The present invention also provides a fluidized bed heat exchange method suitable for ultrafine particles, which is applicable to the fluidized bed heat exchanger for ultrafine particles as described above, and includes the following steps:

[0066] Step S1: Turn on the heat transfer medium supply to the heat exchange tube 2 and introduce the heat transfer medium into the heat exchange tube 2.

[0067] Step S2: Turn on the gas distributor 5 and introduce fluidizing gas into the particle disordered circulation zone 17.

[0068] Step S3: Turn on the feed pipe 14 to supply the gas-solid mixture into the feed zone 15.

[0069] Step S4: Adjust the gas velocity ratio of the gas distributor 5 so that the particles circulate internally along the guide tube 3. After the heat transfer medium exchanges heat with the hot particles, a phase change occurs and the particles flow into the steam drum through the heat exchange tube 2.

[0070] Specifically, the fluidized bed heat exchange method suitable for ultrafine particles is implemented using the aforementioned fluidized bed heat exchanger suitable for ultrafine particles, and the method includes the following steps:

[0071] Step S1: Turn on the heat transfer medium supply to each heat exchange tube 2 and introduce the heat transfer medium into each heat exchange tube 2. In this embodiment, the heat transfer medium introduced is water.

[0072] Step S2: Turn on the central gas distributor 51 and the side wall gas distributor 52, introduce fluidizing gas into the particle disordered circulation zone 17, and adjust the gas flow of the central gas distributor 51 and the side wall gas distributor 52 respectively, so that the particle disordered circulation zone 17 forms a first disordered circulation zone 171 in the center and a second disordered circulation zone 172 surrounding the first disordered circulation zone 171.

[0073] Step S3: Turn on the feed supply of the feed pipe 14 and introduce the gas-solid mixture of reaction gas and particles into the feed zone 15. The particles are rectified by the rectifier plate 4 and then converge and flow to the central guide zone 161.

[0074] Step S4: By adjusting the gas flow rate of the central gas distributor 51 and the sidewall gas distributor 52 respectively, the gas velocity ratio of the gas distributor 5 in the first disordered circulation zone 171 and the second disordered circulation zone 172 is adjusted to a suitable range. Under the continuous influence of the gas velocity difference between the first disordered circulation zone 171 and the second disordered circulation zone 172, the particles undergo internal circulation along the guide tube 3 and react fully with the reaction gas to quickly become hot particles. This accelerates the phase change process of the heat transfer medium in the heat exchange tube 2. After the heat transfer medium undergoes phase change with the hot particles, it flows into the steam drum through the heat exchange tube 2 to supply heat to other systems. The particles that have completed heat exchange are discharged from the outlet 13 at the lower end of the shell 1, and the gas is discharged from the exhaust port 12 at the upper end of the shell 1. During this process, the two-section structure of the guide tube 3 can concentrate most of the gas volume in the central guide zone 161, so that the guide tube 3 can achieve high gas velocity and low density operating conditions. The annular gas distributor 6 is activated to supplement the gas volume in the annular guide zone 162, so that the guide tube 3 and the shell 1 can achieve low gas velocity and high density operating conditions. Through the two different regional operating conditions, the heat transfer coefficient and reaction efficiency in the internal circulation motion of the particles are further improved. In this embodiment, when the gas velocity ratio of the gas distributor 5 in the first disordered circulation zone 171 and the second disordered circulation zone 172 is lower than the above-mentioned suitable range, the difference between the gas velocity in the first disordered circulation zone 171 and the gas velocity in the second disordered circulation zone 172 is small, and the circulation volume of the particles along the guide tube 3 is insufficient, resulting in an insignificant heat transfer effect. If the gas velocity ratio is too low, it may even cause the particles to have difficulty forming an internal circulation motion along the guide tube 3. When the gas velocity ratio of the gas distributor 5 in the first disordered circulation zone 171 and the second disordered circulation zone 172 is higher than the above-mentioned suitable range, the gas in the first disordered circulation zone 171 is easy to diffuse into the second disordered circulation zone, resulting in a smaller difference between the gas velocity in the first disordered circulation zone 171 and the gas velocity in the second disordered circulation zone 172, making it impossible to maintain the circulation volume of the particles along the guide tube 3, resulting in a poor heat transfer effect.

[0075] The fluidized bed heat exchange method for ultrafine particles provided by this invention controls the heat transfer coefficient and reaction efficiency during the internal circulation of particles by adjusting the gas velocity ratio of the gas distributor 5, thus enabling the fluidized bed heat exchanger to also function as a temperature-controlled reactor.

[0076] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A fluidized bed heat exchanger suitable for ultrafine particles, characterized in that, include: The shell has an inlet, an outlet and an outlet. The inlet is inclined upward and has an inlet pipe. The inside of the shell is arranged in sequence along the direction of gravity, including an inlet zone, an ordered particle circulation zone and a disordered particle circulation zone. Heat exchange tubes are inserted at intervals inside the housing; A flow guide tube is disposed in the ordered particle circulation zone, dividing the ordered particle circulation zone into a central flow guide zone and an annular gap flow guide zone. The central flow guide zone is located inside the flow guide tube, and the annular gap flow guide zone is located between the flow guide tube and the shell. The flow guide tube has a constant diameter section and a variable diameter section. The constant diameter section is disposed above the variable diameter section along the direction of gravity, and the diameter of the variable diameter section is enlarged. An annular gap gas distributor is provided in the ordered particle circulation zone, and the annular gap gas distributor is disposed in the annular gap flow guide zone. A rectifier plate is disposed below the feed inlet, which can collect particles entering the feed area from the feed pipe and direct them to the central guide area; A gas distributor is disposed in the particle disordered circulation region. The gas distributor can divide the particle disordered circulation region into a first disordered circulation region and a second disordered circulation region. The first disordered circulation region is located below the central guide region, and the second disordered circulation region is located below the annular gap guide region. Particles entering from the feed inlet can circulate internally between the central guide zone and the annular guide zone along the guide tube under the velocity difference between the first disordered circulation zone and the second disordered circulation zone.

2. The fluidized bed heat exchanger suitable for ultrafine particles according to claim 1, characterized in that, The air velocity in the first disordered circulation zone is greater than that in the second disordered circulation zone. The circulation path direction of the particles in the central guide zone is opposite to the direction of gravity, while the circulation path direction of the particles in the annular gap guide zone is the same as the direction of gravity.

3. The fluidized bed heat exchanger suitable for ultrafine particles according to claim 1, characterized in that, The gas distributor is a dual-gas distributor, which includes a central gas distributor and a sidewall gas distributor. The central gas distributor and the sidewall gas distributor are arranged parallel to each other below the heat exchange tube. Along the direction of gravity, the projected outline of the guide tube is located between the projected outline of the central gas distributor and the projected outline of the sidewall gas distributor.

4. The fluidized bed heat exchanger suitable for ultrafine particles according to claim 1, characterized in that, The angle between the extension direction of the rectifier plate and the direction of gravity is 120°~165°.

5. The fluidized bed heat exchanger suitable for ultrafine particles according to claim 4, characterized in that, The rectifier plate is provided with a plurality of flow guide baffles at intervals parallel to the extension direction of the rectifier plate, or the rectifier plate is provided with a plurality of flow guide grooves at intervals parallel to the extension direction of the rectifier plate.

6. The fluidized bed heat exchanger for ultrafine particles according to claim 1, characterized in that, The central flow guiding zone is provided with a first heat exchange tube that is set vertically, and the annular flow guiding zone is provided with a second heat exchange tube that is set horizontally or vertically.

7. The fluidized bed heat exchanger for ultrafine particles according to claim 6, characterized in that, The first heat exchange tube is a shell-and-tube heat exchange tube or a heat pipe heat exchange tube, and the second heat exchange tube is a heat pipe heat exchange tube or a coil heat exchange tube.

8. The fluidized bed heat exchanger for ultrafine particles according to claim 7, characterized in that, The surface structure of the first heat exchange tube and the second heat exchange tube is one of finned tube, stud tube, and smooth tube.

9. A fluidized bed heat exchange method suitable for ultrafine particles, characterized in that, The method is applicable to fluidized bed heat exchangers suitable for ultrafine particles as described in any one of claims 1 to 8, and includes the following steps: Turn on the heat transfer medium supply to the heat exchange tube and introduce the heat transfer medium into the heat exchange tube; Turn on the gas distributor and introduce fluidizing gas into the particle disorder circulation zone; Turn on the feed pipe to introduce a gas-solid mixture into the feed zone; Adjusting the gas velocity ratio of the gas distributor causes the particles to circulate internally along the guide tube. After heat exchange with the hot particles, the heat transfer medium undergoes a phase change and flows into the steam drum through the heat exchange tube.

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