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

Abstract

The invention relates to a heat transfer strengthening structure, a heat transfer strengthening pipe, a preheating device and application. 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, blockage during flowing of the coal water slurry is prevented, and heat transfer strengthening is facilitated.

Description

Technical Field

[0001] The invention relates to a heat transfer enhancement structure, a heat transfer enhancement tube, a preheating device and applications. Background Art

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

[0003] The traditional entrained-bed gasification wet feeding is to process coal into water-coal slurry with a moisture content of about 40% through equipment such as coal mills, and then feed it into the gasifier through equipment such as coal slurry pumps. Wet feeding is conducive to the stable transportation of raw materials and pressurized gasification. However, because the water-coal slurry has a low inlet temperature (close to room temperature) and the temperature in the gasifier exceeds 1200°C, the water-coal slurry will absorb a lot of heat to heat up after entering the gasifier, which requires more energy and is not conducive to improving gasification efficiency.

[0004] Water-coal slurry preheating technology is one of the effective methods for water-coal slurry gasification technology to achieve high efficiency and low oxygen consumption. After the temperature of the water-coal slurry entering the gasifier increases, it can not only significantly reduce indicators such as specific coal consumption and specific oxygen consumption, but also reduce the viscosity of the water-coal slurry, thereby strengthening the nozzle atomization, which is beneficial to improving the carbon conversion rate.

[0005] However, due to the complex rheological properties of coal water slurry, it is a non-Newtonian slurry with high solid content and high viscosity. Traditional preheating methods and equipment have problems such as low preheating efficiency and easy blockage, which makes it difficult to meet the requirements of coal water slurry preheating. In practice, there is an urgent need for an efficient coal water slurry heat exchange equipment to preheat coal water slurry and improve the gasification efficiency of coal water slurry. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of low preheating efficiency and easy blockage of water-coal slurry in the prior art, and to provide a heat transfer enhancement structure, a heat transfer enhancement pipe, a preheating device and an application. The present invention can reasonably utilize the by-product steam of the system and enhance the preheating effect of water-coal slurry.

[0007] The present invention solves the above technical problems through the following technical solutions:

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

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

[0010] In the present invention, the ratio of the thickness of the water-coal slurry pipe to the inner diameter of the water-coal slurry pipe can be 5:50.

[0011] In the present invention, the protrusion is a modification of the inner wall surface of the water-coal slurry pipe, and serves as a water-coal slurry heat transfer enhancer to prevent the water-coal slurry from being blocked when flowing, thereby helping to enhance heat transfer.

[0012] In the present invention, the protruding structure is preferably a ball cover.

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

[0014] In the present invention, at least one protrusion may be distributed on the outer wall of the water-coal slurry pipe.

[0015] Wherein, the protrusion is a vortex generator, which is used to enhance the heat transfer of steam to the water-coal slurry pipe.

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

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

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

[0019] Furthermore, the height direction of the triangular prism may be parallel to the radial direction of the water-coal slurry pipe.

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

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

[0022] There may be more than one protrusion along the circumferential direction of the outer wall of the water-coal slurry pipe. Preferably, the protrusions are evenly distributed along the circumferential direction of the outer wall of the water-coal slurry pipe. Preferably, the number of the protrusions along the circumferential direction of the outer wall of the water-coal slurry pipe is 8-30, for example, 19.

[0023] In the present invention, the outer wall of the water-coal slurry pipe may also be provided with an annular fin with a hollow structure.

[0024] Wherein, the annular fin can be vertically connected to the outer wall of the water-coal slurry pipe.

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

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

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

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

[0029] The annular fin may be in the shape of a serrated fin, and the number of serrations on the serrated fin may be 8-20.

[0030] In the present invention, the material used for the heat transfer enhancement structure can be carbon steel or stainless steel.

[0031] In a second aspect, the present invention provides a heat transfer enhancement tube, which includes the heat transfer enhancement tube structure as described above.

[0032] In the present invention, the ratio of the spacing of the protrusions along the heat transfer enhancement tube to the height of the protrusions may be (1-10): 1, for example 3: 1.

[0033] In the present invention, at least one protrusion may be distributed on the outer wall of the water-coal slurry pipe, and the ratio of the spacing of the protrusions along the heat transfer enhancement tube to the length of the protrusions may be (1-10): 1, for example 3: 1.

[0034] In the present invention, the outer wall of the water-coal slurry pipe may also be provided with an annular fin of a hollow structure, and the ratio of the spacing of the annular fin along the heat transfer enhancement tube to the inner diameter of the water-coal slurry pipe may be (5-500): 50, for example 50: 50.

[0035] In the present invention, the shape of the heat transfer enhancement tube 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 present invention provides a preheating device, which includes a shell and the heat transfer enhancement tube as described above located in the shell.

[0037] In the present invention, the overall shape of the shell can be a cylinder. Conventionally, a steam inlet and a condensate outlet are respectively provided at the upper and lower ends of the shell.

[0038] In the present invention, the shape of the heat transfer enhancement tube may be a spiral coil, and the ratio of the diameter of the spiral coil to the inner diameter of the shell may be (1-2): 2.6. The ratio of the spacing between each layer of the spiral coil to the inner height of the shell may be (0.03-0.9): 3, for example, 0.3: 3.

[0039] In the present invention, at least one circular baffle may be provided in the shell. The central axis of the circular baffle may coincide with the central axis of the shell. The ratio of the diameter of the circular baffle to the inner diameter of the shell may be 1: (3-6), for example, 0.5: 2.6. There are multiple circular baffles, and the ratio of the spacing between the circular baffles to the inner height of the shell may 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 water-coal slurry pipe may be 2:50.

[0040] In the present invention, a spiral baffle may be further provided in the shell. The central axis of the spiral baffle may 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 may be 1: (1.5-3), for example, 1.6: 2.6. The ratio of the pitch of the spiral baffle to the inner height of the shell may 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 water-coal slurry pipe is 2: 50.

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

[0042] In the present invention, conventionally, the spiral baffle, the circular baffle and the annular baffle can all be fixed in the housing by a support frame.

[0043] In the present invention, the baffle, the annular fins and the projections constitute a steam heat transfer enhancer.

[0044] In a fourth aspect, the present invention provides an application of the preheating device as described above in preheating hot coal slurry.

[0045] In the present invention, the concentration of the coal-water slurry may be 50%-70%, for example 62%, where the percentage is the ratio of the mass of the coal in the coal-water slurry to the mass of the coal-water slurry.

[0046] In the present invention, the viscosity of the water-coal slurry may be 300-1300 mPa·s, for example, 600 mPa·s, and the test temperature of the viscosity is the feed temperature of the water-coal slurry.

[0047] In the present invention, the flow velocity of the water-coal slurry in the heat transfer enhancement tube may be 0.1-3 m / s, for example, 0.5 m / s.

[0048] In the present invention, the preheating device may be preheated by steam. The steam may be byproduct steam of the gasification system. Preferably, it is low-pressure flash steam produced by a low-pressure flash evaporator in the gasification black water system.

[0049] The positive and progressive effects of the present invention are:

[0050] (1) The heat transfer enhancement structure of the present invention has protrusions on the inner wall of the water-coal slurry pipe as inner wall surface modification to prevent blockage during the flow of the water-coal slurry, thereby helping to enhance heat transfer;

[0051] (2) The heat transfer enhancement structure of the present invention may also be provided with a protrusion as a vortex generator for enhancing the heat transfer of steam to the water-coal slurry pipe; and may also be provided with an annular fin;

[0052] (3) The heat transfer enhancement tube of the present invention may be a coil structure with a certain curvature. The above structure is combined and arranged to enhance the preheating effect of the water-coal slurry;

[0053] (4) The preheating device of the present invention can reasonably utilize the by-product steam of the system. In the subsequent coal gasification process, it can reduce the specific coal consumption and specific oxygen consumption, improve the efficiency of water-coal slurry gasification, reduce carbon emissions, and produce raw coal gas with a high effective gas content and low energy consumption and carbon dioxide emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Schematic diagram of the heat transfer enhancement structure in Example 1;

[0055] Figure 2 This is a schematic diagram of the structure of the coal-water slurry preheating device in Example 2;

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

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

[0058] Figure 5 Schematic diagram of the annular fin in Example 2;

[0059] Figure 6 Schematic diagram of annular fins in other embodiments;

[0060] Figure 7is a schematic diagram of a bump in Example 2;

[0061] Figure 8 Schematic diagram of bumps in other embodiments;

[0062] Fig. 9 Schematic diagram of each baffle in Example 2;

[0063] As shown in the figure, the symbols are: heat transfer enhancement tube 1, water-coal slurry tube 10, protrusion 11, bump 12, annular fin 13, feed inlet 14, discharge port 15, outer shell 2, spiral baffle 21, circular baffle 22, annular baffle 23, steam inlet 24, condensate outlet 25. DETAILED DESCRIPTION

[0064] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0065] Example 1

[0066] A heat transfer enhancement tube, comprising: Figure 1 The heat transfer enhancement structure shown in the figure includes a water-coal slurry pipe 10 and ten protrusions 11 evenly distributed on the inner wall of the water-coal slurry pipe 10. The protrusion 11 is a ball cover, and the height of the protrusion 11 is 3 mm. The inner diameter of the water-coal slurry pipe 10 is 50 mm, and the spacing between the protrusions 11 along the heat transfer enhancement pipe 1 is 9 mm.

[0067] Example 2

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

[0069] In this embodiment, Figure 2 The shape of the heat transfer enhancement tube 1 is a spiral coil, and the diameter of the spiral coil gradually increases from 1 m inside to 2 m. The spacing 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 inner height of 3 m.

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

[0071] In this embodiment, the heat transfer enhancement structure further includes an annular fin 13, such as Figure 5 The outer wall of the water-coal slurry pipe 10 is also provided with an annular fin 13 of a porous structure. The annular fin 13 is vertically connected to the outer wall of the water-coal slurry pipe 10. The shape of the annular fin 13 is a porous fin, the height of the annular fin 13 is 60 mm, the thickness of the annular fin 13 is 2 mm, the spacing of the annular fin 13 along the heat transfer enhancement pipe 1 is 50 mm, the hollow area of ​​the annular fin 13 is 35% of the total area, and the pore diameter of the porous structure is 25 mm. In other embodiments, the shape of the annular fin 13 can be a serrated fin, such as Figure 6 .

[0072] In this embodiment, the heat transfer enhancement structure further includes a bump 12, such as Figure 7 , the outer wall of the water-coal slurry pipe 10 is evenly distributed with nineteen protrusions 12, the shape of the protrusions 12 is a triangular prism, one side of the triangular prism is connected to the outer wall of the water-coal slurry pipe 10, the height direction of the triangular prism is parallel to the radial direction of the water-coal slurry pipe 10, the height of the protrusion 12 is 8 mm, the width of the protrusion 12 is 4 mm, the length of the protrusion 12 is 8 mm, and the spacing of the protrusions 12 along the heat transfer enhancement pipe 1 is 24 mm. In other embodiments, the shape of the protrusion 12 is an elliptical column, such as Figure 8 .

[0073] In this embodiment, Fig. 9 , two circular baffles 22 are provided in the housing 2, the central axis of the circular baffles 22 coincides with the central axis of the housing 2, the diameter of the circular baffles 22 is 0.5 m, the spacing 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 provided in the housing 2, the central axis of the annular baffle 23 coincides with the central axis of the housing 2, the outer diameter of the annular baffle 23 is equal to the inner diameter of the housing 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, a spiral baffle 21 is provided in the housing 2, the central axis of the spiral baffle 21 coincides with the central axis of the housing 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 housing 2 by a support frame, and the specific installation position is based on not having obvious contact with the heat transfer enhancement tube 1.

[0075] Example 3

[0076] Compared with the second embodiment, the present embodiment does not include the protrusion 12 .

[0077] Example 4

[0078] Compared with the second embodiment, the annular fin 13 is not provided in the present embodiment.

[0079] Example 5

[0080] Compared with the second embodiment, in the present 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 bump 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 water-coal slurry preheating device of Examples 2-5 and Comparative Examples 1-2 was used. The steam used to heat the water-coal slurry was low-flash steam produced as a byproduct of gasification, about 140°C, and the consumption of flash steam was 2.6 t / h; the concentration of the water-coal slurry was 62%, the viscosity of the water-coal slurry was 600 mPa·s, the flow rate of the water-coal slurry was 0.5 m / s, and the inlet temperature of the water-coal slurry was 50°C. The heat transfer results are shown in the following table:

[0087]

[0088] Application Example 2

[0089] The water-coal slurry preheated by the water-coal slurry preheating device of Example 2 in Application Example 1 was used for gasification reaction, with a gasification temperature of 1200° C. and a pressure of 6.5 MPa.

[0090] The specific oxygen consumption of the preheated water-coal slurry during gasification is 358.3 Nm 3 / kNm 3 CO+H2, specific coal consumption is 546.8 kg / kNm 3 CO+H2; compared with the case without preheating, they save 3.71% and 1.57% respectively, that is, when the water-coal slurry is not preheated and gasified, the specific oxygen consumption is 372.1 Nm 3 / kNm 3 CO+H2, specific coal consumption is 555.6 kg / kNm 3 CO+H2.

[0091] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A heat transfer enhancement structure, characterized in that: It comprises a water-coal slurry pipe (10) and at least one protrusion (11) distributed on the inner wall of the water-coal slurry pipe (10); the ratio of the height of the protrusion (11) to the inner diameter of the water-coal slurry pipe (10) is (1-8):

50.

2. The heat transfer enhancement structure according to claim 1, characterized in that: The ratio of the height of the protrusion (11) to the inner diameter of the water-coal slurry pipe (10) is 3:50; The ratio of the thickness of the water-coal slurry pipe (10) to the inner diameter of the water-coal slurry pipe (10) is 5:50; The structure of the protrusion (11) is a ball cover; The number of the protrusions (11) along the circumferential direction of the inner wall of the water-coal slurry pipe (10) is multiple; the number of the protrusions (11) along the circumferential direction of the inner wall of the water-coal slurry pipe (10) is evenly distributed; the number of the protrusions (11) along the circumferential direction of the inner wall of the water-coal slurry pipe (10) is 4-16, for example 10; The outer wall of the water-coal slurry pipe (10) is also provided with at least one protrusion (12); The outer wall of the water-coal slurry pipe (10) is also provided with an annular fin (13) with a hollow structure; The heat transfer enhancement structure is made of carbon steel or stainless steel.

3. The heat transfer enhancement structure according to claim 2, characterized in that: The ratio of the height of the protrusion (12) to the inner diameter of the water-coal slurry pipe (10) is (5-25): 50, for example 8: 50; The shape of the protrusion (12) is an elliptical cylinder, and the height of the elliptical cylinder is the height of the protrusion (12); The shape of the projection (12) is a triangular prism, and one side surface of the triangular prism is connected to the outer wall of the water-coal slurry pipe (10); the height direction of the triangular prism is parallel to the radial direction of the water-coal slurry pipe (10); the height of the triangular prism is equal to the width of the projection (12), and the ratio of the height to the inner diameter of the water-coal slurry pipe (10) is (3-15): 50, for example (4-9): 50; the width of the surface of the triangular prism connected to the outer wall of the water-coal slurry pipe (10) is equal to the length of the projection (12), and the ratio of the height to the inner diameter of the water-coal 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 water-coal slurry pipe (10) is multiple; the protrusions (12) are evenly distributed along the circumferential direction of the outer wall of the water-coal slurry pipe (10); the number of the protrusions (12) along the circumferential direction of the outer wall of the water-coal slurry pipe (10) is 8-30, for example 19; The annular fin (13) is vertically connected to the outer wall of the water-coal slurry pipe (10); The ratio of the height of the annular fin (13) to the inner diameter of the water-coal slurry pipe (10) is (15-100):50, for example 60:50; The ratio of the thickness of the annular fin (13) to the inner diameter of the water-coal slurry pipe (10) is 2:50; The hollow area of ​​the annular fin (13) is 20%-50%, for example 35%, of the total area of ​​the annular fin (13); The annular fin (13) is in the shape of a porous fin; the ratio of the aperture of the porous fin to the height of the annular fin (13) is (5-45): 60, for example 25: 60; The annular fin (13) is in the shape of a serrated fin; the number of serrations on the serrated fin is 8-20.

4. A heat transfer enhancement tube, characterized in that: It comprises the heat transfer enhancement tube structure as described in any one of claims 1 to 3.

5. The heat transfer enhancement tube according to claim 4, characterized in that: The ratio of the spacing of the protrusions (11) along the heat transfer enhancement tube (1) to the height of the protrusions (11) is (1-10): 1, for example 3: 1; The outer wall of the water-coal slurry pipe (10) is further provided with at least one protrusion (12), and the ratio of the spacing of the protrusions (12) along the heat transfer enhancement pipe (1) to the length of the protrusions (12) is (1-10): 1, for example 3: 1; The outer wall of the water-coal slurry pipe (10) may also be provided with an annular fin (13) of a hollow structure, and the ratio of the spacing of the annular fin (13) along the heat transfer enhancement pipe (1) to the inner diameter of the water-coal slurry pipe (10) is (5-500):50, for example 50:50; The heat transfer enhancement tube (1) is in the shape of 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 in that: It comprises a shell (2) and a heat transfer enhancement tube (1) as claimed in claim 4 or 5 located in the shell (2).

7. The 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 enhancement tube (1) is a spiral coil, and the ratio of the diameter of the spiral coil to the inner diameter of the outer shell (2) is (1-2): 2.6; the ratio of the spacing between each layer of the spiral coil to the inner height of the outer shell (2) is (0.03-0.9): 3, for example 0.3: 3; At least one circular baffle (22) is further 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), for example, 0.5: 2.6; a plurality of circular baffles (22) are provided, and the ratio of the spacing between the circular baffles (22) to the inner height of the shell (2) is (0.2-1.5): 3, for example, 0.5: 3; the ratio of the thickness of the circular baffle (22) to the inner diameter of the water-coal slurry pipe (10) is 2:

50.

8. The preheating device according to claim 6, characterized in that: A spiral baffle (21) is further 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), for example, 1.6: 2.6; the ratio of the pitch of the spiral baffle (21) to the inner height of the shell (2) is (0.2-1.5): 3, for example, 0.5: 3; the ratio of the thickness of the spiral baffle (21) to the inner diameter of the water-coal slurry pipe (10) is 2: 50; An annular baffle (23) is further provided inside the outer shell (2); the central axis of the annular baffle (23) can coincide with the central axis of the outer shell (2); the ratio of the width of the annular baffle (23) to the inner diameter of the outer shell (2) is 1:(2-6), for example 1:2.6; and the ratio of the thickness of the annular baffle (23) to the inner diameter of the water-coal slurry pipe (10) is 2:

50.

9. Use of the preheating device according to any one of claims 6 to 8 in preheating hot coal slurry.

10. Use of the preheating device according to claim 9, characterized in that: The concentration of the coal-water slurry is 50%-70%, for example 62%, where the percentage is the ratio of the mass of the coal in the coal-water slurry to the mass of the coal-water slurry; The viscosity of the coal water slurry is 300-1300 mPa·s, for example 600 mPa·s, and the test temperature of the viscosity is the feed temperature of the coal water slurry; The flow velocity of the water-coal slurry in the heat transfer enhancement tube (1) is 0.1-3 m / s, for example 0.5 m / s; The preheating device uses steam for preheating.

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