Methanol introduction structure for heat treatment furnace

Abstract

This application relates to the field of metal material heat treatment technology, and in particular to a methanol inlet structure for a heat treatment furnace, including a methanol inlet channel and an inert gas inlet channel. Methanol flows into the methanol inlet channel through a methanol inlet and then into the furnace lining through a methanol outlet. Inert gas flows into the inert gas inlet channel through an inert gas inlet and then into the furnace lining through an inert gas outlet. The inert gas does not undergo any chemical reaction inside the furnace and does not absorb heat from the furnace lining. Because the inert gas outlet and the methanol outlet are located adjacent to each other, the high-speed outflow of inert gas from the inert gas outlet creates a negative pressure area near the methanol outlet, which accelerates the flow of methanol and ensures smooth methanol flow into the furnace lining. At the same time, the accelerated flow of methanol has a certain flushing and cleaning effect on the methanol outlet.

Description

Technical Field

[0001] This application relates to the field of heat treatment technology for metallic materials, and in particular to a methanol inlet structure for a heat treatment furnace. Background Technology

[0002] Heat treatment furnaces are used to heat-treat metallic materials to achieve desired properties. Some heat treatment processes, such as carburizing or decarburization prevention heat treatment, require the introduction of carburizing gases, such as methanol, into the furnace lining. The introduced methanol is typically in gaseous or liquid state. Inside the furnace lining, the methanol decomposes into carbon monoxide and hydrogen, providing the basic protective atmosphere. On the surface of the metallic material, carbon monoxide decomposes into carbon dioxide and active carbon atoms. Because the carbon concentration inside the metallic material is much lower than at the surface, the active carbon atoms diffuse from the surface into the interior of the metallic material.

[0003] Currently, most methanol inlet structures in heat treatment furnaces use metal pipes. When methanol flows through, the temperature of the metal pipe drops significantly. When the relatively cool metal pipe comes into contact with methanol, it is easy to produce impurities such as tar, carbon deposits, and gum. These impurities adhere to the inner wall of the metal pipe, causing a certain blockage effect and hindering the flow of methanol.

[0004] The existing technical solutions mentioned above have the following drawbacks: when methanol is introduced into the furnace lining through a metal pipe, a blockage effect is likely to occur, resulting in a non-smooth flow of methanol. Summary of the Invention

[0005] To ensure the smooth flow of methanol, this application provides a methanol inlet structure for a heat treatment furnace.

[0006] This application provides a methanol inlet structure for a heat treatment furnace, employing the following technical solution: A methanol inlet structure for a heat treatment furnace, comprising: A methanol inlet channel is suitable for installation on the furnace lining of a heat treatment furnace, with a methanol inlet at the top and a methanol outlet at the bottom. An inert gas inlet channel is suitable for installation on a furnace lining. An inert gas inlet is formed at the top and an inert gas outlet is formed at the bottom. The inert gas outlet is located adjacent to the methanol outlet.

[0007] By adopting the above technical solution, methanol flows into the methanol input channel through the methanol inlet and then into the furnace lining through the methanol outlet. Inert gas flows into the inert gas input channel through the inert gas inlet and then into the furnace lining through the inert gas outlet. Because the inert gas outlet and the methanol outlet are located adjacent to each other, the high-speed outflow of inert gas from the inert gas outlet creates a negative pressure area near the methanol outlet, which accelerates the flow of methanol and ensures smooth flow into the furnace lining. Simultaneously, the accelerated methanol flow has a flushing and cleaning effect on the methanol outlet, preventing blockage.

[0008] This application further specifies that the methanol input channel and the inert gas input channel are arranged on parallel axes; The methanol input channel includes: The first ceramic inner liner tube has a methanol inlet at the top and a methanol passage at the bottom. The first metal outer tube is fitted over the first ceramic inner tube. The top end has a through hole for the top end of the first ceramic inner tube to pass through, and the bottom end has a closed structure. A methanol outlet is formed at the bottom of the side near the inert gas input channel.

[0009] By adopting the above technical solution, the methanol input channel and the inert gas input channel are designed independently, effectively simplifying the structural complexity and reducing manufacturing and maintenance costs. The first ceramic liner does not chemically react with methanol at high temperatures, thus preventing wear and extending the service life of the methanol input channel. With a higher specific heat capacity than metal materials, the temperature drop of the first ceramic liner is smaller when methanol flows through it, reducing the generation of tar, carbon deposits, and gum-like impurities. This helps to solve the blockage problem to some extent, eliminating the need for regular unclogging of the methanol input channel, avoiding wear and tear, and extending its service life. The first metal outer sleeve protects the first ceramic liner, preventing damage during transportation or installation. Placing the methanol outlet on one side of the first metal outer sleeve, compared to placing it at the bottom, prevents methanol from directly spraying onto the heat-treated metal material, thus avoiding localized temperature drops and the generation of large amounts of carbon deposits due to methanol decomposition. It also avoids the problem of low localized hardness in heat-treated parts. The high-speed flow of inert gas creates a negative pressure zone on the right side of the methanol outlet, accelerating the methanol's movement to the right and ensuring smooth flow of methanol into the furnace lining. Because the flow directions of methanol and inert gas are perpendicular, the methanol is dispersed by the inert gas as it flows into the furnace lining, preventing localized cracking of the methanol and resulting in a sudden drop in temperature. This reduces the amount of carbon deposits inside the furnace lining, leading to a more uniform atmosphere distribution and improved heat treatment quality.

[0010] This application further specifies that: the bottom end of the first ceramic liner tube is flush with the upper edge of the methanol outlet; the bottom end of the inert gas input channel is flush with the upper edge of the methanol outlet.

[0011] This application further specifies that the methanol input channel and the inert gas input channel are arranged with their axes collinear; The methanol input channel includes: The second ceramic inner tube has a methanol inlet at the top of one side and a methanol outlet at the bottom. A ceramic inner core is inserted into a second ceramic inner liner tube, and a first swirl groove is formed on its outer wall. The inert gas input channel includes: The second metal outer tube is fitted over the second ceramic inner tube. The inner wall of the outer tube and the outer wall of the second ceramic inner tube form an inert gas flow cavity. An inert gas inlet is formed at the top and an inert gas outlet is formed at the bottom.

[0012] By adopting the above technical solution, the methanol input channel and the inert gas input channel are coaxially arranged, effectively improving the integration level, making the structure more compact, and saving installation space. The second ceramic liner tube does not chemically react with methanol at high temperatures, thus preventing wear and extending the service life of the methanol input channel. With a higher specific heat capacity than metal materials, the temperature drop of the second ceramic liner tube is smaller when methanol flows through it, reducing the generation of tar, carbon deposits, and gum-like impurities. This helps to solve the blockage problem to some extent, eliminating the need for regular unclogging of the methanol input channel, avoiding wear and tear, and extending the service life of the methanol input channel. The second metal outer sleeve protects the second ceramic liner tube, preventing damage during transportation or installation. The high-speed flowing inert gas creates a negative pressure area below the methanol outlet, accelerating the downward movement of methanol and ensuring smooth flow into the furnace lining. Methanol flows into the second ceramic liner tube from one side and flows out from the methanol outlet in a swirling state using the first swirling groove on the outer wall of the ceramic core. On the one hand, the swirling flow ensures uniform mixing of methanol and inert gas below the methanol outlet; on the other hand, coaxial flow also promotes uniform mixing. This prevents localized temperature drops caused by methanol cracking within the furnace lining, reduces carbon buildup inside the lining, and ensures a uniform atmosphere distribution, thus improving heat treatment quality. Furthermore, the inert gas flowing directly downwards around the methanol outlet prevents contact between methanol and the metal outer jacket, extending its service life.

[0013] This application further specifies that: the second metal outer sleeve is provided with a contraction tube section, a throat section and an expansion tube section from top to bottom.

[0014] By employing the above technical solution, inert gas flows into the contraction section from the inert gas inlet at a subsonic speed, gradually being accelerated to near the speed of sound. As the inert gas flows through the throat section, its velocity reaches the speed of sound. The inert gas then flows into the expansion section at the speed of sound, gradually being accelerated to supersonic speed. By further increasing the velocity of the inert gas flowing around the methanol outlet, the inflow velocity of methanol can be further increased, thereby further ensuring the smooth flow of methanol.

[0015] This application further specifies that the inert gas input channel also includes: Heated wire mesh is installed at the top of the shrink tube section.

[0016] By adopting the above technical solution, the heating wire mesh is used to heat the inert gas flowing through it. During the downward flow of the inert gas, the second ceramic liner tube is heated, compensating for the heat carried away by the methanol flow, reducing the generation of tar, carbon deposits, and gum-like impurities, and lowering the possibility of blockage.

[0017] This application further specifies that the bottom end face of the second metal outer tube is lower than the bottom end face of the second ceramic inner tube in the vertical direction.

[0018] This application further specifies that: the ceramic inner core has a hollow structure, with an inert gas inlet at the top and an inert gas outlet at the bottom, and a second swirl groove formed on the inner wall.

[0019] By adopting the above technical solution, inert gas can flow into the interior of the ceramic core through the inert gas inlet and then into the interior of the furnace lining through the inert gas outlet. A second swirling groove on the inner wall of the ceramic core allows the inert gas to flow out of the inert gas outlet in a low-speed swirling state. On one hand, the low-speed swirling inert gas, the swirling methanol, and the high-speed direct-flow inert gas mix below the methanol outlet, resulting in uniform methanol dispersion. On the other hand, radially, the sequence from the inside out—inert gas, methanol, and then more inert gas—facilitates uniform mixing of methanol and inert gas.

[0020] This application further includes: Inert gas delivery pipe, used to transport inert gases; The first flow regulating valve has its input end connected to the inert gas delivery pipe and its output end connected to the inert gas inlet. The second flow regulating valve has its input end connected to the inert gas supply pipe and its output end connected to the inert gas inlet. Methanol delivery pipe, used to transport methanol; The third flow regulating valve has its input end connected to the methanol delivery pipe and its output end connected to the methanol inlet.

[0021] This application further includes: The controller is connected to the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve, respectively.

[0022] In summary, the beneficial technical effects of this application are as follows: 1. Methanol flows into the methanol input channel through the methanol inlet and then into the furnace lining through the methanol outlet. Inert gas flows into the inert gas input channel through the inert gas inlet and then into the furnace lining through the inert gas outlet. Because the inert gas outlet and methanol outlet are located close together, the high-speed outflow of inert gas creates a negative pressure area near the methanol outlet, accelerating the flow of methanol and ensuring smooth flow into the furnace lining. Simultaneously, the accelerated methanol flow has a flushing and cleaning effect on the methanol outlet, preventing blockage.

[0023] 2. The methanol inlet channel and the inert gas inlet channel are designed independently, effectively simplifying the structural complexity and reducing manufacturing and maintenance costs. The first ceramic liner does not chemically react with methanol at high temperatures, thus preventing wear and extending the service life of the methanol inlet channel. Its higher specific heat capacity compared to metal materials means that the temperature drop of the first ceramic liner is smaller when methanol flows through it, reducing the generation of tar, carbon deposits, and gum-like impurities. This helps to alleviate blockages to some extent, eliminating the need for regular unclogging of the methanol inlet channel and avoiding wear from unclogging, further extending its service life. The first metal outer sleeve protects the first ceramic liner, preventing damage during transportation or installation. Placing the methanol outlet on one side of the first metal outer sleeve, compared to placing it at the bottom, prevents methanol from directly spraying onto the heat-treated metal material, thus avoiding localized temperature drops and the formation of large amounts of carbon deposits due to methanol decomposition. It also avoids the problem of low localized hardness in heat-treated parts. The high-speed flow of inert gas creates a negative pressure zone on the right side of the methanol outlet, accelerating the methanol's movement to the right and ensuring smooth flow of methanol into the furnace lining. Because the flow directions of methanol and inert gas are perpendicular, the methanol is dispersed by the inert gas as it flows into the furnace lining, preventing localized cracking of the methanol and resulting in a sudden drop in temperature. This reduces the amount of carbon deposits inside the furnace lining, leading to a more uniform atmosphere distribution and improved heat treatment quality.

[0024] 3. The methanol inlet channel and the inert gas inlet channel are coaxially arranged, effectively improving the integration level, making the structure more compact, and saving installation space. The second ceramic liner tube does not chemically react with methanol at high temperatures, thus avoiding wear and tear and extending the service life of the methanol inlet channel. With a higher specific heat capacity than metal materials, the temperature drop of the second ceramic liner tube is smaller when methanol flows through it, reducing the generation of tar, carbon deposits, and gum impurities, which helps to solve the blockage problem to some extent. Regular cleaning of the methanol inlet channel is unnecessary, avoiding wear and tear and extending its service life. The second metal outer sleeve protects the second ceramic liner tube, preventing damage during transportation or installation. The high-speed flowing inert gas creates a negative pressure area below the methanol outlet, accelerating the downward movement of methanol and ensuring smooth flow into the furnace lining. Methanol flows into the second ceramic liner tube from one side and flows out of the methanol outlet in a swirling state using the first swirl groove on the outer wall of the ceramic core. On the one hand, the swirling flow ensures uniform mixing of methanol and inert gas below the methanol outlet; on the other hand, coaxial flow also promotes uniform mixing. This prevents localized temperature drops caused by methanol cracking within the furnace lining, reduces carbon buildup inside the lining, and ensures a uniform atmosphere distribution, thus improving heat treatment quality. Furthermore, the inert gas flowing directly downwards around the methanol outlet prevents contact between methanol and the metal outer jacket, extending its service life.

[0025] 4. The second metal outer casing is provided with a contraction section, a throat section, and an expansion section from top to bottom. Inert gas flows into the contraction section from the inert gas inlet at a subsonic speed, gradually accelerating to near the speed of sound. The inert gas reaches the speed of sound as it flows through the throat section. The inert gas then flows into the expansion section at the speed of sound, gradually accelerating to supersonic speed. By further increasing the velocity of the inert gas flowing around the methanol outlet, the inflow velocity of methanol can be further increased, thereby further ensuring the smooth flow of methanol.

[0026] 5. A heating wire mesh is installed at the top of the contraction tube section to heat the inert gas flowing through it. As the inert gas flows downwards, it heats the second ceramic liner tube, compensating for the heat carried away by the methanol flow, reducing the amount of tar, carbon deposits, and gum-like impurities generated, and lowering the possibility of blockage.

[0027] 6. Inert gas flows into the interior of the ceramic core through the inert gas inlet and then into the interior of the furnace lining through the inert gas outlet. A second swirling groove on the inner wall of the ceramic core allows the inert gas to flow out of the inert gas outlet in a low-speed swirling state. On one hand, the low-speed swirling inert gas, the swirling methanol, and the high-speed direct-flow inert gas mix below the methanol outlet, resulting in uniform methanol dispersion. On the other hand, radially, the sequence from the inside out—inert gas, methanol, and then more inert gas—facilitates uniform mixing of methanol and inert gas. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the first embodiment of the methanol inlet structure for a heat treatment furnace; Figure 2 This is a schematic diagram of the second embodiment of the methanol inlet structure for a heat treatment furnace; Figure 3 This is a schematic diagram of the third embodiment of the methanol inlet structure for a heat treatment furnace; Figure 4 This is a schematic diagram of the fourth embodiment of the methanol inlet structure for a heat treatment furnace; Figure 5 This is a schematic diagram of the fifth embodiment of the methanol inlet structure for a heat treatment furnace; Figure 6 This is a schematic diagram of the sixth embodiment of the methanol inlet structure for a heat treatment furnace.

[0029] Reference numerals: 110, Methanol input channel; 111, First ceramic inner liner tube; 112, First metal outer sleeve tube; 113, Second ceramic inner liner tube; 114, Ceramic inner core; 120, Inert gas input channel; 121, Second metal outer sleeve tube; 1211, Contraction section; 1212, Throat section; 1213, Expansion section; 122, Heating wire mesh; 130, Inert gas delivery pipe; 140, First flow regulating valve; 150, Second flow regulating valve; 160, Methanol delivery pipe; 170, Third flow regulating valve; 200, Furnace lining. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0031] Reference Figure 1This application discloses a methanol inlet structure for a heat treatment furnace, including a methanol inlet channel 110 and an inert gas inlet channel 120. The methanol inlet channel 110 is suitable for installation on the furnace lining 200 of the heat treatment furnace, with a methanol inlet at the top and a methanol outlet at the bottom. Methanol flows into the methanol inlet channel 110 and then into the furnace lining 200 through the methanol outlet. The inert gas inlet channel 120 is suitable for installation on the furnace lining 200, with an inert gas inlet at the top and an inert gas outlet at the bottom. Inert gases such as nitrogen, helium, or neon flow into the inert gas inlet channel 120 and then into the furnace lining 200 through the inert gas outlet. Methanol absorbs heat and decomposes into carbon monoxide and hydrogen within the furnace lining 200, providing a basic protective atmosphere. On the surface of the metal material, carbon monoxide decomposes into carbon dioxide and active carbon atoms. Because the carbon concentration inside the metal material is much lower than at the surface, active carbon atoms diffuse from the surface of the metal material into its interior. The inert gas does not undergo any chemical reaction inside the furnace and does not absorb heat from the furnace lining 200. Because the inert gas outlet is located adjacent to the methanol outlet, the high-speed outflow of the inert gas creates a negative pressure zone near the methanol outlet, which accelerates the flow of methanol and ensures smooth flow into the furnace lining 200. Simultaneously, the accelerated methanol flow also has a flushing and cleaning effect on the methanol outlet.

[0032] Reference Figure 1In one embodiment, the methanol input channel 110 and the inert gas input channel 120 are arranged parallel to each other on their axes. The methanol input channel 110 and the inert gas input channel 120 are designed independently, effectively simplifying the structural complexity and reducing manufacturing and maintenance costs. The methanol input channel 110 includes a first ceramic inner liner tube 111 and a first metal outer sleeve tube 112. The top end of the first ceramic inner liner tube 111 has a methanol inlet, and the bottom end has a methanol outlet. The first metal outer sleeve tube 112 is fitted over the first ceramic inner liner tube 111, with a through hole at its top for the top end of the first ceramic inner liner tube 111 to pass through, and a closed structure at its bottom, with a methanol outlet at the bottom near the inert gas input channel 120. Methanol flows sequentially through the methanol inlet, the interior of the first ceramic inner liner tube 111, the methanol outlet, and the methanol outlet before entering the interior of the furnace lining 200. The first ceramic inner liner tube 111 can be made of silicon nitride or silicon carbide, etc. Compared to metal materials, it does not chemically react with methanol at high temperatures, thus preventing loss and extending the service life of the methanol input channel 110. Its specific heat capacity is higher than that of metal materials; therefore, when methanol flows through the first ceramic inner liner 111, the temperature drop of the first ceramic inner liner 111 is smaller, reducing the generation of tar, carbon deposits, and gum-like impurities. This helps to alleviate blockage problems to some extent, eliminating the need for regular cleaning of the methanol input channel 110, avoiding wear and tear from cleaning, and extending the service life of the methanol input channel 110. The first metal outer liner 112 can be made of stainless steel or copper, protecting the first ceramic inner liner 111 and preventing damage during transportation or installation. Placing the methanol outlet on one side of the first metal outer liner 112, compared to placing it at the bottom, prevents methanol from directly spraying onto the heat-treated metal material, thus avoiding methanol decomposition and the resulting sudden temperature drop and large amount of carbon deposits. At the same time, it avoids the problem of low local hardness in parts that have undergone heat treatment. Figure 1 The middle arrow indicates the flow direction of methanol and inert gas. Methanol flows into the furnace lining 200 from left to right. Inert gas flows into the furnace lining 200 at high speed from top to bottom. The high-speed flow of inert gas creates a negative pressure area on the right side of the methanol outlet, accelerating the methanol's movement to the right and ensuring smooth flow of methanol into the furnace lining 200. Because the flow directions of methanol and inert gas are perpendicular to each other, the methanol is dispersed by the inert gas when it flows into the furnace lining 200, preventing localized cracking of methanol within the lining 200 and thus avoiding sudden drops in localized temperature. This reduces the amount of carbon deposits inside the furnace lining 200, resulting in a more uniform atmosphere distribution and improving the quality of heat treatment.

[0033] It should be noted that when the methanol inlet channel 110 and the inert gas inlet channel 120 are designed independently, two adjacent mounting holes need to be opened on the furnace lining 200. One mounting hole is used to install the methanol inlet channel 110, and the other mounting hole is used to install the inert gas inlet channel 120.

[0034] Preferably, the bottom end of the first ceramic liner tube 111 is flush with the upper edge of the methanol outlet, ensuring that methanol can flow smoothly out of the methanol outlet. The bottom end of the inert gas inlet channel 120 is flush with the upper edge of the methanol outlet, ensuring an acceleration effect on the methanol flow.

[0035] Preferably, the size of the methanol outlet is larger than the size of the methanol inlet, which plays a diffusion role and prevents a large amount of methanol from cracking in local locations inside the furnace lining 200.

[0036] Preferably, the first ceramic liner 111 includes an upper guide pipe section and a lower guide pipe section. The axis of the upper guide pipe section is horizontally arranged, while the axis of the lower guide pipe section is vertically arranged. One end of the upper guide pipe section is connected to one side of the top of the lower guide pipe section, and they are internally connected. The end away from the lower guide pipe section is the methanol inlet. The bottom end of the lower guide pipe section is the methanol outlet. The diameter of the lower guide pipe section is larger than the diameter of the upper guide pipe section.

[0037] Reference Figure 2In one embodiment, the methanol input channel 110 and the inert gas input channel 120 are arranged collinearly. This effectively improves the integration level, makes the structure more compact, and saves installation space. The methanol input channel 110 includes a second ceramic liner tube 113 and a ceramic core 114. A methanol inlet is formed at the top of one side of the second ceramic liner tube 113, and a methanol outlet is formed at the bottom. Methanol flows sequentially through the methanol inlet, the interior of the second ceramic liner tube 113, and the methanol outlet before entering the interior of the furnace lining 200. The ceramic core 114 is inserted into the second ceramic liner tube 113, and a first swirl groove is formed on its outer wall. The second ceramic liner tube 113 and the ceramic core 114 can be made of silicon nitride or silicon carbide, etc. Compared with metal materials, they do not chemically react with methanol at high temperatures, thus avoiding wear and tear and extending the service life of the methanol input channel 110. The inert gas has a higher specific heat capacity than metal materials. Therefore, when methanol flows through the second ceramic liner tube 113, the temperature drop of the second ceramic liner tube 113 is smaller, reducing the generation of tar, carbon deposits, and gum-like impurities. This helps to solve the blockage problem to some extent, eliminating the need for regular cleaning of the methanol input channel 110, avoiding wear and tear from cleaning, and extending the service life of the methanol input channel 110. The inert gas input channel 120 includes a second metal outer sleeve 121. The second metal outer sleeve 121 is fitted over the second ceramic liner tube 113, and the inner wall of the second ceramic liner tube 113 forms an inert gas flow cavity. An inert gas inlet is formed at the top, and an inert gas outlet is formed at the bottom. The second metal outer sleeve 121 can be made of stainless steel or copper, etc., to protect the second ceramic liner tube 113 and prevent damage to the second ceramic liner tube 113 during transportation or installation. The inert gas enters the furnace lining 200 after passing through the inert gas inlet, the inert gas flow cavity, and the inert gas outlet in sequence. Figure 2The direction of the arrows indicates the flow of methanol and inert gas. The inert gas flows downwards in a direct current around the methanol outlet. The high-speed flow of the inert gas creates a negative pressure zone below the methanol outlet, accelerating the downward movement of methanol and ensuring smooth flow into the furnace lining 200. Methanol flows into the second ceramic lining tube 113 from one side and exits from the methanol outlet in a swirling state using the first swirling groove on the outer wall of the ceramic core 114. On one hand, the swirling state allows for uniform mixing of methanol and inert gas below the methanol outlet; on the other hand, coaxial flow also facilitates uniform mixing. This avoids localized temperature drops caused by methanol cracking within the furnace lining 200, reduces carbon buildup inside the furnace lining 200, and ensures a uniform atmosphere distribution inside the furnace lining 200, thus improving the quality of heat treatment. In addition, the inert gas flowing directly downwards through the methanol outlet can prevent methanol from contacting the second metal outer sleeve 121, thus extending the service life of the second metal outer sleeve 121.

[0038] It should be noted that when the methanol inlet channel 110 and the inert gas inlet channel 120 are aligned with the same axis, only one mounting hole needs to be made on the furnace lining 200. This helps to reduce the risk of gas leakage.

[0039] Preferably, the size of the methanol outlet is larger than the size of the methanol inlet, which plays a diffusion role and prevents a large amount of methanol from cracking in local locations inside the furnace lining 200.

[0040] Reference Figure 3 In one embodiment, the second metal outer sleeve 121 is provided with a contraction section 1211, a throat section 1212 and an expansion section 1213 from top to bottom. Figure 3 The middle arrow indicates the flow direction of methanol and inert gas. The inert gas flows into the contraction section 1211 from the inert gas inlet at subsonic speed, gradually accelerating to near-sonic speed. As the inert gas flows through the throat section 1212, its velocity reaches the speed of sound. The inert gas then flows into the expansion section 1213 at sonic speed, gradually accelerating to supersonic speed. By further increasing the velocity of the inert gas flowing around the methanol outlet, the inflow velocity of methanol can be further increased, thereby further ensuring the smoothness of methanol inflow.

[0041] Reference Figure 4 In one embodiment, the inert gas inlet channel 120 further includes a heating wire mesh 122. The heating wire mesh 122 is installed at the top of the contraction tube section 1211 and is used to heat the flowing inert gas. During the downward flow of the inert gas, the second ceramic liner tube 113 can be heated to compensate for the heat carried away by the methanol flow, thereby reducing the amount of tar, carbon deposits, and gum impurities generated and reducing the possibility of blockage.

[0042] Preferably, the bottom end face of the second metal outer tube 121 is lower than the bottom end face of the second ceramic inner tube 113 in the vertical direction. In this way, a mixing chamber is reserved below the bottom end face of the second ceramic inner tube 113, which helps to improve the uniformity of mixing.

[0043] Reference Figure 5 In one embodiment, an inert gas inlet is formed at the top of the ceramic core 114, an inert gas outlet is formed at the bottom, and a second swirling groove is formed on the inner wall. The inert gas flows into the interior of the ceramic core 114 through the inert gas inlet and then into the interior of the furnace lining 200 through the inert gas outlet. The second swirling groove on the inner wall of the ceramic core 114 causes the inert gas to flow out of the inert gas outlet in a low-speed swirling state. On the one hand, the low-speed swirling inert gas, the swirling methanol, and the high-speed direct-flow inert gas mix below the methanol outlet, resulting in uniform methanol dispersion. On the other hand, radially, from the inside out, the sequence of inert gas, methanol, and then inert gas facilitates uniform mixing of methanol and inert gas.

[0044] Reference Figure 6 In one embodiment, the methanol inlet structure for the heat treatment furnace further includes an inert gas delivery pipe 130, a first flow regulating valve 140, a second flow regulating valve 150, a methanol delivery pipe 160, a third flow regulating valve 170, and a controller (not shown in the figure). The inert gas delivery pipe 130 is used to deliver inert gas. The input end of the first flow regulating valve 140 is connected to the inert gas delivery pipe 130, and the output end is connected to the inert gas inlet, used to control the flow rate and volume of the inert gas flowing to the inert gas inlet. The input end of the second flow regulating valve 150 is connected to the inert gas supply pipe, and the output end is connected to the inert gas inlet, used to control the flow rate and volume of the inert gas flowing to the inert gas inlet. The methanol delivery pipe 160 is used to deliver methanol. The input end of the third flow regulating valve 170 is connected to the methanol delivery pipe 160, and the output end is connected to the methanol inlet, used to control the flow rate and volume of the methanol flowing to the methanol inlet. The controller is electrically connected to the first flow regulating valve 140, the second flow regulating valve 150, and the third flow regulating valve 170 respectively, and is used to control the opening degree of the first flow regulating valve 140, the second flow regulating valve 150, and the third flow regulating valve 170.

[0045] The implementation principle of this embodiment is as follows: Methanol flows into the methanol input channel 110 through the methanol inlet and then into the furnace lining 200 through the methanol outlet. Inert gas flows into the inert gas input channel 120 through the inert gas inlet and then into the furnace lining 200 through the inert gas outlet. Within the furnace lining 200, methanol absorbs heat and decomposes into carbon monoxide and hydrogen, providing a basic protective atmosphere. On the surface of the metal material, carbon monoxide decomposes into carbon dioxide and active carbon atoms. Because the carbon concentration inside the metal material is much lower than on the surface, active carbon atoms diffuse from the surface into the interior of the metal material. The inert gas does not undergo any chemical reaction within the furnace and does not absorb heat from the furnace lining 200. Since the inert gas outlet is located adjacent to the methanol outlet, the high-speed outflow of inert gas from the inert gas outlet creates a negative pressure area near the methanol outlet, which accelerates the flow of methanol, ensuring smooth flow into the furnace lining 200. Simultaneously, the accelerated flow of methanol has a certain flushing and cleaning effect on the methanol outlet.

[0046] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A methanol inlet structure for a heat treatment furnace, characterized in that, include: A methanol inlet channel (110) is suitable for installation on the furnace lining (200) of a heat treatment furnace, with a methanol inlet at the top and a methanol outlet at the bottom. An inert gas inlet channel (120) is suitable for installation on the furnace lining (200), with an inert gas inlet formed at the top and an inert gas outlet formed at the bottom; the inert gas outlet is located adjacent to the methanol outlet.

2. The methanol inlet structure for a heat treatment furnace according to claim 1, characterized in that, The methanol input channel (110) and the inert gas input channel (120) are arranged side by side along their axes; The methanol input channel (110) includes: The first ceramic inner liner tube (111) has a methanol inlet formed at the top and a methanol passage formed at the bottom. The first metal outer tube (112) is fitted over the first ceramic inner tube (111). The top end has a through hole for the top end of the first ceramic inner tube (111) to pass through, and the bottom end has a closed structure. The methanol outlet is formed at the bottom of the side near the inert gas input channel (120).

3. The methanol inlet structure for a heat treatment furnace according to claim 2, characterized in that, The bottom end of the first ceramic liner tube (111) is flush with the upper edge of the methanol outlet; the bottom end of the inert gas inlet channel (120) is flush with the upper edge of the methanol outlet.

4. The methanol inlet structure for a heat treatment furnace according to claim 1, characterized in that, The methanol input channel (110) and the inert gas input channel (120) are arranged with their axes collinear; The methanol input channel (110) includes: The second ceramic inner liner tube (113) has a methanol inlet formed at the top of one side and a methanol outlet formed at the bottom. A ceramic inner core (114) is inserted into the second ceramic inner liner tube (113), and a first swirl groove is formed on its outer wall; The inert gas input channel (120) includes: The second metal outer sleeve (121) is sleeved outside the second ceramic inner liner (113). The inner wall of the sleeve and the outer wall of the second ceramic inner liner (113) form an inert gas flow cavity. The top end has an inert gas inlet and the bottom end has an inert gas outlet.

5. The methanol inlet structure for a heat treatment furnace according to claim 4, characterized in that, The second metal outer tube (121) is provided with a contraction tube section (1211), a throat section (1212), and an expansion tube section (1213) from top to bottom.

6. The methanol inlet structure for a heat treatment furnace according to claim 5, characterized in that, The inert gas input channel (120) also includes: A heating wire mesh (122) is installed at the top of the shrink tube section (1211).

7. The methanol inlet structure for a heat treatment furnace according to claim 4, characterized in that, The bottom surface of the second metal outer tube (121) is lower than the bottom surface of the second ceramic inner tube (113) in the vertical direction.

8. The methanol inlet structure for a heat treatment furnace according to claim 4, characterized in that, The ceramic core (114) has a hollow structure with an inert gas inlet at the top and an inert gas outlet at the bottom, and a second swirl groove on the inner wall.

9. The methanol inlet structure for a heat treatment furnace according to claim 8, characterized in that, Also includes: Inert gas delivery pipe (130), used for delivering inert gas; The first flow regulating valve (140) has its input end connected to the inert gas delivery pipe (130) and its output end connected to the inert gas inlet. The second flow regulating valve (150) has its input end connected to the inert gas supply pipe and its output end connected to the inert gas inlet. Methanol delivery pipe (160), used for transporting methanol; The third flow regulating valve (170) has its input end connected to the methanol delivery pipe (160) and its output end connected to the methanol inlet.

10. The methanol inlet structure for a heat treatment furnace according to claim 9, characterized in that, Also includes: The controller is connected to the first flow regulating valve (140), the second flow regulating valve (150), and the third flow regulating valve (170), respectively.

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