Heat transfer strengthening structure, heat transfer strengthening pipe and preheating device

Abstract

The utility model provides a heat transfer strengthening structure, a heat transfer strengthening pipe and a preheating device. The heat transfer strengthening structure comprises a coal water slurry pipe and at least one protrusion distributed on the inner wall of the coal water slurry pipe. The ratio of the height of the protrusions to the inner diameter of the coal water slurry pipe is (1-8): 50. The heat transfer strengthening pipe comprises the heat transfer strengthening pipe structure. The preheating device comprises a shell and the heat transfer strengthening pipe located in the shell. According to the heat transfer strengthening structure, the protrusions are arranged on the inner wall of the coal water slurry pipe and serve as inner wall face modification, blocking during flowing of coal water slurry is prevented, and heat transfer strengthening is facilitated.

Description

TECHNICAL FIELD

[0001] The utility model relates to a heat transfer strengthening structure, heat transfer strengthening pipe, preheating device. BACKGROUND

[0002] Coal gasification technology is one of the core technologies of clean and efficient utilization of coal, and the synthesis gas produced by coal gasification can develop coal-based chemicals (such as fertilizers, methanol, aromatics, olefins, ethylene glycol, etc.), coal-based fuels (such as natural gas, oil), which can be used for IGCC power generation, poly-generation system, hydrogen production, etc.

[0003] Traditional entrained flow bed gasification wet feeding is to process coal into coal water slurry with a water content of about 40% through a coal mill and other equipment, and then send it into the gasification furnace through a coal slurry pump and other equipment. Wet feeding is conducive to stable conveying of raw materials and pressurized gasification. However, because the inlet temperature of the coal water slurry is low (close to room temperature), and the temperature in the gasification furnace exceeds 1200℃, the coal water slurry will first absorb a large amount of heat to warm up after entering the gasification furnace, which requires more energy consumption and is not conducive to improving the gasification efficiency.

[0004] Coal water slurry preheating technology is one of the effective methods for realizing high efficiency and low oxygen consumption of coal water slurry gasification technology. After increasing the temperature of the coal water slurry entering the gasification furnace, not only can the specific coal consumption and specific oxygen consumption and other indicators be significantly reduced, but also the viscosity of the coal water slurry can be reduced, thereby strengthening the nozzle atomization and being conducive to improving the carbon conversion rate.

[0005] However, due to the complex rheological properties of coal water slurry, which is a non-Newtonian slurry with high solid content and high viscosity, the traditional preheating method and equipment have the problems of low preheating efficiency and easy plugging, which is difficult to meet the preheating requirements of coal water slurry. In practice, there is an urgent need for an efficient coal water slurry heat exchange equipment to preheat the coal water slurry and improve the gasification efficiency of the coal water slurry. UTILITY MODEL CONTENTS

[0006] The technical problem to be solved by the utility model is to overcome the defects of low preheating efficiency and easy plugging of the existing technology, and to provide a heat transfer strengthening structure, a heat transfer strengthening pipe and a preheating device. The utility model can reasonably utilize system by-product steam and strengthen the preheating effect of the coal water slurry.

[0007] The utility model solves the above technical problems by the following technical solutions:

[0008] In the first aspect, the utility model provides a heat transfer strengthening structure, which comprises a coal water slurry pipe and at least one protrusion distributed on the inner wall of the coal water slurry pipe; the ratio of the height of the protrusion to the inner diameter of the coal water slurry pipe is (1-8): 50.

[0009] In the utility model, the ratio of the height of the protrusion to the inner diameter of the coal water slurry pipe can be 3: 50.

[0010] The ratio of the thickness of the coal water slurry pipe to the inner diameter of the coal water slurry pipe can be 5:50.

[0011] In the utility model, the protrusions are used for decorating the inner wall of the coal water slurry pipe and serve as a heat transfer intensifier for coal water slurry, preventing the coal water slurry from being blocked when flowing and helping to intensify heat transfer.

[0012] In the utility model, the protrusions are preferably spherical caps.

[0013] In the utility model, the number of the protrusions along the circumferential direction of the inner wall of the coal water slurry pipe can be multiple. Preferably, the protrusions are evenly distributed along the circumferential direction of the inner wall of the coal water slurry pipe. Preferably, the number of the protrusions along the circumferential direction of the inner wall of the coal water slurry pipe can be 4-16, for example, 10.

[0014] In the utility model, the outer wall of the coal water slurry pipe can also be provided with at least one protrusion.

[0015] The protrusion is a vortex generator for intensifying heat transfer of steam to the coal water slurry pipe.

[0016] The ratio of the height of the protrusion to the inner diameter of the coal water slurry pipe can be (5-25):50, for example, 8:50.

[0017] The shape of the protrusion can be an elliptic cylinder, that is, a flow-shaped vortex generator, and the height of the elliptic cylinder is the height of the protrusion.

[0018] The shape of the protrusion can be a triangular prism, a wing-shaped vortex generator, and a wedge body. One side of the triangular prism is connected to the outer wall of the coal water slurry pipe.

[0019] Further, the height direction of the triangular prism can be parallel to the radial direction of the coal water slurry pipe.

[0020] Further, the height of the triangular prism is the width of the protrusion, and the ratio of the width to the inner diameter of the coal water slurry pipe can be (3-15):50, for example, (4-9):50.

[0021] Further, the width of the side of the triangular prism connected to the outer wall of the coal water slurry pipe is the length of the protrusion, and the ratio of the length to the inner diameter of the coal water slurry pipe can be (3-15):50, (8-9):50.

[0022] The number of the protrusions along the circumferential direction of the outer wall of the coal water slurry pipe can be multiple. Preferably, the protrusions are evenly distributed along the circumferential direction of the outer wall of the coal water slurry pipe. Preferably, the number of the protrusions along the circumferential direction of the outer wall of the coal water slurry pipe can be 8-30, for example, 19.

[0023] The outer wall of the coal water slurry pipe can be further provided with annular fins with hollow structures.

[0024] The annular fins can be connected perpendicularly to the outer wall of the coal water slurry pipe.

[0025] The ratio of the height of the annular fin to the inner diameter of the coal water slurry pipe can be (15-100): 50, for example, 60: 50.

[0026] The ratio of the thickness of the annular fin to the inner diameter of the coal water slurry pipe can be 2: 50.

[0027] The hollow area of the annular fin can be 20%-50% of the total area of the annular fin, for example, 35%.

[0028] The shape of the annular fin can be a porous fin. The ratio of the pore diameter of the porous fin to the height of the annular fin can be (5-45): 60, for example, 25: 60.

[0029] The shape of the annular fin can be a sawtooth fin. The number of sawteeth on the sawtooth fin can be 8-20.

[0030] The material of the heat transfer strengthening structure can be carbon steel or stainless steel.

[0031] In a second aspect, the utility model provides a kind of heat transfer strengthening pipe, it includes the heat transfer strengthening pipe structure as described above.

[0032] The ratio of the spacing of the protrusions along the heat transfer strengthening pipe to the height of the protrusions can be (1-10): 1, for example, 3: 1.

[0033] The outer wall of the coal water slurry pipe can further be distributed with at least one protrusion, and the ratio of the spacing of the protrusions along the heat transfer strengthening pipe to the length of the protrusions can be (1-10): 1, for example, 3: 1.

[0034] The outer wall of the coal water slurry pipe can be further provided with annular fins with hollow structures, and the ratio of the spacing of the annular fins along the heat transfer strengthening pipe to the inner diameter of the coal water slurry pipe can be (5-500): 50, for example, 50: 50.

[0035] The shape of the heat transfer strengthening pipe can be a spiral coil. The feed inlet and the discharge outlet of the spiral coil can be located on the same side.

[0036] In a third aspect, the utility model provides a preheating device, which includes a shell and a heat transfer strengthening pipe as described above located in the shell.

[0037] In the utility model, the overall shape of the shell can be a cylinder, according to convention, the upper and lower ends of the shell are respectively provided with a steam inlet and a condensate outlet.

[0038] In the utility model, the shape of the heat transfer reinforced pipe can be a spiral coil pipe, the ratio of the diameter of the spiral coil pipe to the inner diameter of the shell can be (1-2): 2.6. The ratio of the spacing between each layer of coil pipe of the spiral coil pipe to the internal height of the shell can be (0.03-0.9): 3, for example 0.3: 3.

[0039] In the utility model, at least one circular baffle can be further arranged in the shell. The central axis of the circular baffle can coincide with the central axis of the shell. The ratio of the diameter of the circular baffle to the inner diameter of the shell can be 1: (3-6), for example 0.5: 2.6. A plurality of circular baffles are arranged, the ratio of the spacing between each circular baffle to the internal height of the shell can be (0.2-1.5): 3, for example 0.5: 3. The ratio of the thickness of the circular baffle to the inner diameter of the coal water slurry pipe can be 2: 50.

[0040] In the utility model, a spiral baffle can be further arranged in the shell. The central axis of the spiral baffle can coincide with the central axis of the shell. The ratio of the difference between the outer diameter of the spiral baffle and the inner diameter of the spiral baffle to the inner diameter of the shell can be 1: (1.5-3), for example 1.6: 2.6. The ratio of the pitch of the spiral baffle to the internal height of the shell can be (0.2-1.5): 3, for example 0.5: 3. The ratio of the thickness of the spiral baffle to the inner diameter of the coal water slurry pipe can be 2: 50.

[0041] In the utility model, an annular baffle can be further arranged in the shell. The central axis of the annular baffle can coincide with the central axis of the shell. The ratio of the width of the annular baffle to the inner diameter of the shell can be 1: (2-6), for example 1: 2.6. The ratio of the thickness of the annular baffle to the inner diameter of the coal water slurry pipe can be 2: 50.

[0042] In the utility model, according to convention, the spiral baffle, the circular baffle and the annular baffle can be fixed in the shell by a support frame.

[0043] In the utility model, the baffle, the annular fin and the convex block constitute a steam heat transfer intensifier.

[0044] In the fourth aspect, the utility model provides a kind of application of the preheating device in preheating coal water slurry as described above.

[0045] The concentration of the coal water slurry can be 50%-70%, for example, 62%, and the percentage is the mass ratio of the coal in the coal water slurry to the mass of the coal water slurry.

[0046] In the utility model, the viscosity of the coal water slurry can be 300-1300 mPa·s, for example, 600 mPa·s, and the test temperature of the viscosity is the feeding temperature of the coal water slurry.

[0047] In the utility model, the flow speed of the coal water slurry in the heat transfer reinforced pipe can be 0.1-3 m / s, for example, 0.5 m / s.

[0048] In the utility model, the preheating device can adopt steam preheating, and the steam can be by-product steam of a gasification system.

[0049] The positive progress effect of the utility model is that:

[0050] (1) the heat transfer reinforced structure of the utility model is provided with a protrusion on the inner wall of the coal water slurry pipe, which is used as an inner wall decoration and prevents the coal water slurry from being blocked when flowing, and helps to strengthen heat transfer;

[0051] (2) the heat transfer reinforced structure of the utility model can also be provided with a protruding block, which is used as a vortex generator and is used for strengthening the heat transfer of steam to the coal water slurry pipe; and can also be provided with an annular fin;

[0052] (3) the heat transfer reinforced pipe of the utility model can be a coil structure with a certain curvature, and the above-mentioned structure combination is arranged to strengthen the preheating effect of the coal water slurry;

[0053] (4) the preheating device of the utility model can reasonably utilize system by-product steam, can reduce the specific coal consumption and the specific oxygen consumption in the subsequent coal gasification process, improves the efficiency of the coal water slurry gasification, reduces carbon emission, and the effective gas content of the prepared crude coal gas is high, and the energy consumption and carbon dioxide emission are low. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is a schematic view of the heat transfer reinforced structure in embodiment 1;

[0055] Figure 2 It is a schematic view of the coal water slurry preheating device structure in embodiment 2;

[0056] Figure 3 It is a side view of the coal water slurry preheating device in embodiment 2;

[0057] Figure 4 It is a partial sectional view of the coal water slurry preheating device in embodiment 2;

[0058] Figure 5A schematic diagram of the ring-shaped fins in Example 2;

[0059] Figure 6 A schematic diagram of the ring-shaped fins in other examples;

[0060] Figure 7 A schematic diagram of the protrusions in Example 2;

[0061] Figure 8 A schematic diagram of the protrusions in other examples;

[0062] Figure 9 A schematic diagram of the various baffles in Example 2;

[0063] The reference signs in the figure: heat transfer enhanced tube 1, coal water slurry tube 10, protrusion 11, protrusion 12, ring-shaped fin 13, feed inlet 14, discharge outlet 15, shell 2, spiral baffle 21, circular baffle 22, ring-shaped baffle 23, steam inlet 24, condensate outlet 25. DETAILED DESCRIPTION

[0064] The preferred embodiments will be described below in detail with reference to the accompanying drawings.

[0065] Example 1

[0066] A heat transfer enhanced tube, comprising a heat transfer enhanced structure as shown in Figure 1 , the heat transfer enhanced structure comprising a coal water slurry tube 10 and ten protrusions 11 evenly distributed on the inner wall of the coal water slurry tube 10, the structure of the protrusions 11 being a ball cap, the height of the protrusions 11 being 3 mm. The inner diameter of the coal water slurry tube 10 is 50 mm, and the pitch of the protrusions 11 along the heat transfer enhanced tube 1 is 9 mm.

[0067] Example 2

[0068] A coal water slurry preheating device, as shown in Figures 2-3 , comprising a shell 2 and a heat transfer enhanced tube 1 located in the shell 2. The shell 2 is provided with a steam inlet 24 and a condensate outlet 25, and the heat transfer enhanced tube 1 is provided with a feed inlet 14 and a discharge outlet 15 at both ends, located on the same side. The materials of the shell 2 and the heat transfer enhanced tube 1 are both stainless steel.

[0069] In this embodiment, as shown in Figure 2 , the shape of the heat transfer enhanced tube 1 is a spiral coil, and the diameter of the spiral coil gradually increases from 1 m inside to 2 m. The pitch between each layer of the spiral coil is 0.3 m, and the total length of the spiral coil in the shell 2 is about 50 m. In this embodiment, the overall shape of the shell 2 is a cylinder, with an inner diameter of 2.6 m and an internal height of 3 m.

[0070] In this embodiment, the heat transfer enhanced tube 1, as shown in Figure 1, including heat transfer enhancement tube structure, heat transfer enhancement structure includes water coal slurry pipe 10 and ten evenly distributed in the inner wall of water coal slurry pipe 10 protrusions 11, the structure of protrusion 11 is ball cover, the height of protrusion 11 is 3 mm. The inner diameter of water coal slurry pipe 10 is 50 mm, and the pitch of protrusion 11 along the heat transfer enhancement tube 1 is 9 mm.

[0071] In this embodiment, the heat transfer enhancement structure further includes annular fin 13, as Figure 5 , the outer wall of water coal slurry pipe 10 is also provided with annular fin 13 of porous structure. Annular fin 13 is connected perpendicularly with the outer wall of water coal slurry pipe 10. The shape of annular fin 13 is porous fin, the height of annular fin 13 is 60 mm, the thickness of annular fin 13 is 2 mm, the pitch of annular fin 13 along the heat transfer enhancement tube 1 is 50 mm, the hollow area of annular fin 13 is 35% of the total area, and the pore size of the porous structure is 25 mm. In other embodiments, the shape of annular fin 13 can be sawtooth fin, as Figure 6 .

[0072] In this embodiment, the heat transfer enhancement structure further includes protrusion 12, as Figure 7 , the outer wall of water coal slurry pipe 10 is also evenly distributed with nineteen protrusions 12, the shape of protrusion 12 is triangular prism, one side of the triangular prism is connected with the outer wall of water coal slurry pipe 10, the height direction of the triangular prism is parallel to the radial direction of water coal slurry pipe 10, the height of protrusion 12 is 8 mm, the width of protrusion 12 is 4 mm, the length of protrusion 12 is 8 mm, and the pitch of protrusion 12 along the heat transfer enhancement tube 1 is 24 mm. In other embodiments, the shape of protrusion 12 can be elliptic cylinder, as Figure 8 .

[0073] In this embodiment, as Figure 9 , two circular baffles 22 are arranged in the shell 2, the central axis of the circular baffles 22 coincides with the central axis of the shell 2, the diameter of the circular baffles 22 is 0.5 m, the pitch between the two circular baffles 22 is 0.5 m, and the thickness of the circular baffles 22 is 2 mm. In this embodiment, an annular baffle 23 is arranged in the shell 2, the central axis of the annular baffle 23 coincides with the central axis of the shell 2, the outer diameter of the annular baffle 23 is equal to the inner diameter of the shell 2, the width of the annular baffle 23 is 1 m, and the thickness of the annular baffle 23 is 2 mm.

[0074] In this embodiment, the shell 2 is provided with a spiral baffle 21, the central axis of the spiral baffle 21 coincides with the central axis of the shell 2, the inner diameter of the spiral baffle 21 is 1 m, the spiral width of the spiral baffle 21 is 1.6 m, the pitch of the spiral baffle 21 is 0.5 m, and the thickness of the spiral baffle 21 is 2 mm. In this embodiment, the spiral baffle 21, the circular baffle 22 and the annular baffle 23 are all fixed in the shell 2 by support frames, and the specific installation position is determined according to whether obvious contact with the heat transfer enhanced tube 1 occurs.

[0075] Example 3

[0076] Compared with Example 2, in this embodiment, the protrusion 12 is not provided.

[0077] Example 4

[0078] Compared with Example 2, in this embodiment, the annular fin 13 is not provided.

[0079] Example 5

[0080] Compared with Example 2, in this embodiment, the spiral baffle 21, the circular baffle 22 and the annular baffle 23 are not provided.

[0081] Comparative Example 1

[0082] Compared with Example 2, in this comparative example, the protrusion 11, the protrusion 12, the annular fin 13, the spiral baffle 21, the circular baffle 22 and the annular baffle 23 are not provided.

[0083] Comparative Example 2

[0084] Compared with Example 2, in this comparative example, the height of the protrusion 11 is too high, which is 10 mm.

[0085] Application Example 1

[0086] The coal water slurry preheating devices of Examples 2-5 and Comparative Examples 1-2 are used. The steam for heating the coal water slurry is the by-product low flash steam of gasification, about 140℃, and the consumption of the flash steam is 2.6 t / h; the concentration of the coal water slurry is 62%, the viscosity of the coal water slurry is 600 mPa·s, the flow rate of the coal water slurry is 0.5 m / s, and the inlet temperature of the coal water slurry is 50℃. The heat transfer results are shown in the following table:

[0087]

[0088] Application Example 2

[0089] The coal water slurry preheated by the coal water slurry preheating device of Example 2 in Application Example 1 is used for gasification reaction, the gasification temperature is 1200℃, and the pressure is 6.5 MPa.

[0090] The specific oxygen consumption of the preheated coal water slurry is 358.3 Nm 3 / kNm 3 The specific coal consumption of CO+H2 is 546.8 kg / kNm 3 CO+H2; compared with the case without preheating, 3.71% and 1.57% are saved respectively, that is, the specific oxygen consumption of the coal water slurry without preheating is 372.1 Nm 3 / kNm 3 The specific coal consumption of CO+H2 is 555.6 kg / kNm 3 CO+H2.

[0091] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, but these changes and modifications all fall within the protection scope of the present application.

Claims

1. A heat transfer enhancement structure, characterized by, The ratio of the height of the protrusion (11) to the inner diameter of the coal water slurry pipe (10) is (1-8):

50.

2. The heat transfer enhancement structure according to claim 1, wherein The ratio of the height of the protrusion (11) to the inner diameter of the coal water slurry pipe (10) is 3: 50; The ratio of the thickness of the coal water slurry pipe (10) to the inner diameter of the coal water slurry pipe (10) is 5: 50; The structure of the protrusion (11) is a ball cap; The number of the protrusions (11) along the circumferential direction of the inner wall of the coal water slurry pipe (10) is multiple; the protrusions (11) are uniformly distributed along the circumferential direction of the inner wall of the coal water slurry pipe (10); the number of the protrusions (11) along the circumferential direction of the inner wall of the coal water slurry pipe (10) is 4-16; The outer wall of the coal water slurry pipe (10) is further provided with at least one protrusion (12); The outer wall of the coal water slurry pipe (10) is further provided with a hollow annular fin (13); The material of the heat transfer strengthening structure is carbon steel or stainless steel.

3. The heat transfer enhancement structure according to claim 2, wherein The ratio of the height of the protrusion (12) to the inner diameter of the coal water slurry pipe (10) is (5-25): 50; The shape of the protrusion (12) is an elliptic cylinder, and the height of the elliptic cylinder is the height of the protrusion (12); The shape of the protrusion (12) is a triangular prism, and one side of the triangular prism is connected with the outer wall of the coal water slurry pipe (10); The height direction of the triangular prism is parallel to the radial direction of the coal water slurry pipe (10); The height of the triangular prism is the width of the protrusion (12), and the ratio of the height to the inner diameter of the coal water slurry pipe (10) is (3-15): 50; The width of the side of the triangular prism connected with the outer wall of the coal water slurry pipe (10) is the length of the protrusion (12), and the ratio of the width to the inner diameter of the coal water slurry pipe (10) is (3-15): 50, (8-9): 50; The number of the protrusions (12) along the circumferential direction of the outer wall of the coal water slurry pipe (10) is multiple; the protrusions (12) are uniformly distributed along the circumferential direction of the outer wall of the coal water slurry pipe (10); The number of the protrusions (12) along the circumferential direction of the outer wall of the coal water slurry pipe (10) is 8-30; The annular fin (13) is connected with the outer wall of the coal water slurry pipe (10) perpendicularly; The ratio of the height of the annular fin (13) to the inner diameter of the coal water slurry pipe (10) is (15-100): 50; The ratio of the thickness of the annular fin (13) to the inner diameter of the coal water slurry pipe (10) is 2: 50; The hollow area of the annular fin (13) is 20%-50% of the total area of the annular fin (13); The shape of the annular fin (13) is a porous fin; The ratio of the pore diameter of the porous fin to the height of the annular fin (13) is (5-45): 60; The shape of the annular fin (13) is a sawtooth fin, and the number of the sawteeth on the sawtooth fin is 8-20.

4. A heat transfer enhancement tube characterized by, The heat transfer strengthening pipe structure comprises the heat transfer strengthening pipe structure according to any one of claims 1-3.

5. The heat transfer enhancement tube according to claim 4, characterized by The ratio of the pitch of the heat transfer enhanced tube (1) to the height of the protrusion (11) is (1-10): 1; The outer wall of the coal water slurry pipe (10) is also provided with at least one protrusion (12), and the ratio of the pitch of the heat transfer enhanced tube (1) to the length of the protrusion (12) is (1-10): 1; The outer wall of the coal water slurry pipe (10) can also be provided with a hollow annular fin (13), and the ratio of the pitch of the heat transfer enhanced tube (1) to the inner diameter of the coal water slurry pipe (10) is (5-500): 50; The shape of the heat transfer enhanced tube (1) is a spiral coil; The feed inlet and the discharge outlet of the spiral coil are located on the same side.

6. A preheating device, characterized by It comprises a shell (2) and a heat transfer enhanced tube (1) as claimed in claim 4 or 5 located in the shell (2).

7. A preheating device according to claim 6, characterized in that The overall shape of the shell (2) is a cylinder; the upper and lower ends of the shell (2) are respectively provided with a steam inlet and a condensate outlet; The shape of the heat transfer enhanced tube (1) is a spiral coil, and the ratio of the diameter of the spiral coil to the inner diameter of the shell (2) is (1-2): 2.6; The ratio of the pitch between each layer of the spiral coil to the internal height of the shell (2) is (0.03-0.9):

3.

8. A preheating device according to claim 6, characterized in that At least one circular baffle (22) is also provided in the shell (2); The central axis of the circular baffle (22) coincides with the central axis of the shell (2); The ratio of the diameter of the circular baffle (22) to the inner diameter of the shell (2) is 1: (3-6); A plurality of circular baffles (22) are provided, and the ratio of the pitch between each circular baffle (22) to the internal height of the shell (2) is (0.2-1.5): 3; The ratio of the thickness of the circular baffle (22) to the inner diameter of the coal water slurry pipe (10) is 2:

50.

9. The preheating device according to claim 6, characterized in that A spiral baffle (21) is also provided in the shell (2); The central axis of the spiral baffle (21) coincides with the central axis of the shell (2); The ratio of the difference between the outer diameter of the spiral baffle (21) and the inner diameter of the spiral baffle (21) to the inner diameter of the shell (2) is 1: (1.5-3); The ratio of the pitch of the spiral baffle (21) to the internal height of the shell (2) is (0.2-1.5): 3; The ratio of the thickness of the spiral baffle (21) to the inner diameter of the coal water slurry pipe (10) is 2:

50.

10. The preheating device of claim 6, wherein A ring-shaped baffle (23) is also provided in the shell (2); The central axis of the ring-shaped baffle (23) can coincide with the central axis of the shell (2); The ratio of the width of the ring-shaped baffle (23) to the inner diameter of the shell (2) is 1: (2-6); The ratio of the thickness of the ring-shaped baffle (23) to the inner diameter of the coal water slurry pipe (10) is 2: 50.

Images