TFB oxygen-enriched gasification chamber and gasifier

Abstract

The present invention discloses a TFB oxygen-enriched gasification chamber and a gasifier, wherein the gasifier comprises a variable cross-section section at the bottom and an upper straight section at the top, wherein the variable cross-section section comprises a lower conical section at the bottom, and a high thermal conductivity and wear-resistant wall surface is selected. The high thermal conductivity and wear-resistant wall surface is composed of a sealing steel plate, a water-cooling pipe row and a silicon carbide refractory material layer, wherein the sealing steel plate is arranged on the outermost layer as the outer wall surface, the silicon carbide refractory material layer is arranged as the inner wall surface, and the water-cooling pipe row is arranged in the silicon carbide refractory material layer and is arranged close to the sealing steel plate. The upper straight section adopts a membrane water-cooled wall surface, and a high-aluminum refractory layer is applied to its inner wall surface, and the water-cooling pipe row of the lower conical section is connected to the membrane water-cooled wall surface of the transition straight section through a header. The gasifier comprises a gasifier chamber and a waste heat boiler and a purification device connected in sequence. The present invention has the advantages of high gasification intensity, high gasification efficiency, stable and controllable operation, etc.

Description

Technical Field

[0001] The invention relates to a TFB oxygen-enriched gasification chamber and a gasifier, in particular to a TFB oxygen-enriched gasification chamber and a gasifier that can be used for urban domestic garbage, and belongs to the technical field of gasification and combustion. Background Art

[0002] At present, the most mature method of heat treatment of domestic waste is incineration. Due to the complex composition, variable form and low calorific value of domestic waste, in order to achieve full combustion and reduce pollutant emissions, technologies such as pyrolysis incineration or gasification incineration have also been developed. However, the waste gasification technology that obtains gasification gas as the target product has always faced problems such as low gasification efficiency, poor stability of the gasifier, high pollutant content in the synthesis gas, low calorific value of the synthesis gas, and poor economic efficiency.

[0003] Patent document CN101850350A proposes a method for treating urban solid waste by oxygen-enriched gasification, which proposes controlling the moisture content of urban domestic waste to less than 25%, and then transporting it to a gasifier to use oxygen-enriched gas as a fluidizing medium for gasification. It is found through chemical thermodynamic equilibrium calculation based on Gibbs minimum free energy that under oxygen-enriched gasification conditions, as the amount of oxygen increases, the reaction time is shortened, the reaction temperature is higher, and the reaction is more complete, which is conducive to improving the gasification efficiency.

[0004] Since oxygen-enriched gasification often reduces the amount of air by increasing the amount of pure oxygen, which means that increasing the oxygen concentration will reduce the amount of carrier gas, thereby significantly reducing the fluidizing gas velocity, patent document CN106635178A proposes a fluidized bed oxygen-enriched gasification method in which an oxygen-enriched mixed gas formed by mixing oxygen and carrier gas is introduced into a fluidized bed gasifier, wherein the carrier gas is carbon dioxide or water vapor. It is also believed that the heat released by the combustion reaction of oxygen and C is partially offset by the heat absorbed by the gasification reaction of carbon dioxide or water vapor and C, thereby avoiding the local temperature runaway phenomenon in the fluidized bed gasifier. Summary of the invention

[0005] The object of the present invention is to provide a TFB oxygen-enriched gasification chamber and a gasifier. On the one hand, the bottom of the lower cone section of the TFB furnace type is adopted to avoid a significant reduction in the fluidization wind speed in the turbulent bed; on the other hand, a silicon carbide refractory layer with high thermal conductivity is adopted in the lower cone section (dense phase zone), and a bare membrane water-cooled wall structure is adopted in the transition straight section and the upper cone section, so that the heat generated in the gasification chamber during the oxygen-enriched gasification process can be quickly conducted, thereby avoiding local temperature runaway.

[0006] The present invention is achieved through the following technical solutions:

[0007] The TFB oxygen-enriched gasification chamber comprises a variable cross-section section at the bottom and an upper straight section at the top, wherein the variable cross-section section comprises a lower cone section, a transition straight section and an upper cone section from bottom to top; a primary gasification agent distribution device is arranged at the bottom of the lower cone section, which can distribute oxygen-enriched gas as a primary gasification agent; the lower cone section adopts a high thermal conductivity and wear-resistant wall surface, and the high thermal conductivity and wear-resistant wall surface comprises a sealing steel plate, a water-cooling pipe row and a silicon carbide refractory material layer, the sealing steel plate is arranged in the outermost layer as the outer wall surface, the silicon carbide refractory material layer is used as the inner wall surface, and the water-cooling pipe row is arranged in the silicon carbide refractory material layer and is arranged close to the sealing steel plate; the transition straight section, the upper cone section and the upper straight section adopt a membrane water-cooled wall surface, and the inner wall surface of the upper straight section is coated with a high-aluminum refractory layer; the water-cooling pipe row of the lower cone section is connected to the membrane water-cooled wall surface of the transition straight section through a header.

[0008] In the above technical solution, the silicon carbide refractory material layer is made of silicon carbide refractory material with a content greater than or equal to 60%, preferably greater than or equal to 85%.

[0009] In the above technical solution, the primary gasification agent distribution device also includes a steam distribution device.

[0010] In the above technical solution, the gasification chamber also includes a secondary gasification agent distribution device and a tertiary gasification agent distribution device, which can distribute and spray oxygen-enriched or pure oxygen as the secondary gasification agent and the tertiary gasification agent to form graded gasification; the secondary gasification agent distribution device includes a lower secondary gasification agent distribution nozzle arranged at the upper part of the lower cone section and an upper secondary gasification agent distribution nozzle arranged at the upper part of the upper cone section, and the tertiary gasification agent distribution device includes a tertiary gasification agent distribution nozzle arranged at the lower part of the upper straight section.

[0011] The TFB oxygen-enriched gasifier comprises the gasification chamber as described above, and a waste heat boiler and a purification device connected in sequence. The waste heat boiler uses a return flue including a descending channel and an ascending channel. A gasification gas outlet is provided on one side of the top of the gasification chamber and is connected to the descending channel inlet of the waste heat boiler.

[0012] Furthermore, a convection heating surface is provided in the upward passage of the waste heat boiler.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0014] 1) Oxygen-enriched gasification has high intensity and efficiency, and can obtain gasification gas with purer components and higher calorific value. The use of the bottom of the lower cone section of the TFB furnace also avoids a significant reduction in the fluidization wind speed in the turbulent bed caused by the reduction of the fluidizing medium.

[0015] 2) The lower wall of the gasification chamber is made of silicon carbide refractory material with high thermal conductivity and densely arranged water-cooled pipe rows, which can prevent wear and enhance heat exchange. When the oxygen-rich / pure oxygen gasification intensity is high, it is more conducive to stabilizing and controlling the gasification temperature.

[0016] 3) A high-aluminum refractory layer is laid on the upper wall of the gasification chamber to achieve wear-resistant and heat-insulating properties, providing conditions for high-temperature gasification in the upper part of the gasification chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the oxygen-enriched gasification TFB gasifier involved in the present invention.

[0018] Figure 2 This is a schematic diagram of the high thermal conductivity and wear-resistant wall structure of the lower cone section involved in the present invention.

[0019] Figure 3 This is a schematic diagram of the wall structure of the high-alumina refractory layer involved in the present invention.

[0020] Figure 4 It is a schematic diagram of the connection structure between the lower cone section and the transition straight section involved in the present invention.

[0021] In the figure: 1-variable cross-section section; 2-upper straight section; 3-primary gasifier distribution device; 4-waste heat boiler; 5-purification device; 6-lower secondary gasifier distribution nozzle; 7-upper secondary gasifier distribution nozzle; 8-tertiary gasifier distribution nozzle; 9-lower cone section; 10-high-aluminum refractory layer; 11-convection heating surface; 12-feed port; 13-header; 901-sealing steel plate; 902-water-cooled pipe row; 903-grabbing nails; 904-silicon carbide refractory material layer; 1001-membrane water-cooled wall; 1002-insulation bricks; 1003-high-aluminum bricks; 1004-pins. DETAILED DESCRIPTION

[0022] The specific implementation and working process of the present invention are further described below in conjunction with the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0023] The directional terms such as top, bottom, left, right, front and back in this application document are established based on the positional relationship shown in the drawings. If the drawings are different, the corresponding positional relationship may also change accordingly, so it cannot be understood as a limitation on the scope of protection. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the following embodiments, the meaning of "multiple" and "several" is two or more, unless otherwise clearly and specifically defined.

[0024] like Figure 1 As shown, a TFB oxygen-enriched gasification furnace includes a TFB oxygen-enriched gasification chamber (hereinafter referred to as the gasification chamber), a waste heat boiler 4 and a purification device 5 connected in sequence. The waste heat boiler 4 uses a return flue including a downward channel and an upward channel, and a gasification gas outlet is provided on one side of the top of the gasification chamber, which is connected to the downward channel inlet of the waste heat boiler 4. Furthermore, a convection heating surface 11 is provided in the upward channel of the waste heat boiler. An inertial separation chamber is formed at the bottom of the return flue, and an ash hopper is formed at the bottom of the inertial separation chamber, which can collect solid particles carried in the gasification gas as medium ash. An ash discharge port is provided at the bottom of the ash hopper, which can discharge medium ash from time to time.

[0025] The gasification chamber includes a variable cross-section section 1 at the bottom and an upper straight section 2 at the top. The variable cross-section section 1 includes a lower cone section 9, a transition straight section and an upper cone section from bottom to top, and the lower cone section has the smallest cross-sectional area. The upper straight section 2 is connected to the top of the upper cone section and is set at the same cross-sectional area as the minimum cross-sectional area at the top of the upper cone section.

[0026] Temperature is an important influencing parameter of the gasification process, which directly affects the gasification intensity and the composition and calorific value of the synthesis gas. Research literature shows that when the calorific value of domestic waste is high, higher temperatures improve the gasification conditions of the waste, thereby producing a large amount of small molecule synthesis gas. Higher bed temperatures will also promote carbon conversion and cracking of macromolecular compounds, thereby reducing the formation of coke and tar. However, under a reducing atmosphere, glass, alkali metals, etc. in waste often melt below 800°C, which not only affects the gasification reaction, but also affects the stability of the gasifier. In oxygen-rich gasification conditions, the gasification intensity is greater and the gasification reaction is faster. The heat after the reaction needs to be conducted more intensively to avoid heat accumulation and excessive temperature.

[0027] The lower cone section 9 uses a high heat conductivity and wear-resistant wall surface, which includes a sealing steel plate 901, a water cooling pipe row 902 and a silicon carbide refractory material layer 904. The water cooling pipe row 902 includes a plurality of water cooling pipes. Figure 2As shown, the sealing steel plate 901 is arranged as the outer wall surface in the outermost layer, the water-cooling tube row 902 is arranged close to the sealing steel plate 901, and the silicon carbide refractory material is poured around the water-cooling tubes in the water-cooling tube row 902 to form a silicon carbide refractory material layer 904 as the inner wall surface. The silicon carbide refractory material layer uses a silicon carbide refractory material with a content greater than or equal to 60% (preferably greater than or equal to 85%), which has excellent thermal conductivity and excellent fire resistance and wear resistance. Since the water-cooling tube row is arranged as a whole in the silicon carbide refractory layer, the overall heat transfer area is maximized. Different from the standard membrane water-cooled wall structure, only half of the water-cooling tube wall is used as the heat contact surface.

[0028] like Figure 2 As shown, the high thermal conductivity and wear-resistant wall surface also includes a number of grabbing nails 903, which are mainly used to fix the refractory layer and enhance heat transfer. Some of the grabbing nails are distributed between the water-cooling tube rows. At this time, one end of the grabbing nail is welded to the sealing steel plate, and the other end is buried in the silicon carbide refractory layer. One end of some of the grabbing nails is directly welded to the outer wall of the water-cooling tube row to enhance heat transfer. In order to enhance heat exchange, the water-cooling tubes in the water-cooling tube row are arranged in a dense arrangement. The dense arrangement is preferably arranged according to the arrangement that only one row of grabbing nails is arranged between the water-cooling tube rows. At the same time, there are also densely arranged grabbing nails, and the dense arrangement of grabbing nails can enhance the heat transfer effect.

[0029] The transition straight section, upper cone section and upper straight section are made of membrane water-cooled wall surfaces, and the inner wall surface of the upper straight section is covered with a high-aluminum refractory layer. While ensuring the sealing of the furnace body, the exposed membrane water-cooled wall of the transition straight section and the upper cone section can also be used to absorb the heat generated by fuel gasification, further adjusting the temperature inside the gasifier.

[0030] The water-cooling tube row of the lower cone section 9 is connected to the membrane water-cooling wall structure (water-cooling tubes therein) of the transition straight section through the header 13. The membrane water-cooling wall fins extend to the header, and the outer wall of the lower cone section 9 - the sealing steel plate also extends to the header to form a sealing structure, which can not only ensure sealing, but also solve the structural problems caused by the different spacing between the upper and lower tubes. A concave part is formed on the inner side (inside the furnace) of the header connection. To avoid wear, this place is filled with the same refractory material and nails as the lower cone section, so that its inner side forms a transition straight section, such as Figure 4 shown.

[0031] The gasification chamber is provided with a primary gasification agent distribution device, a secondary gasification agent distribution device and a tertiary gasification agent distribution device, which can distribute and inject oxygen-enriched gas (oxygen content greater than 21%) as the primary gasification agent, the secondary gasification agent and the tertiary gasification agent to form graded gasification. While the gasification chamber is graded gasification, the temperature is also controlled by zone. In one embodiment, the temperature of the lower part (lower cone section) of the gasification chamber is 600-750°C, the temperature of the middle part (including the transition straight section and the upper cone section) is 750-850°C, and the temperature of the upper straight section is 850-950°C.

[0032] The primary gasification agent distribution device is arranged at the bottom of the lower cone section 9, including a primary gasification agent air distribution chamber and an air distribution plate and a hood arranged at the top of the air distribution chamber, etc., which can be introduced with oxygen-enriched gas as the primary gasification agent. It also includes a steam distribution device, which can be introduced with steam as a regulating gasification agent, and can regulate the temperature by adjusting the steam injection amount. In one preferred embodiment, an online carbon content sensor can be arranged in the ash hopper formed at the bottom of the return flue of the waste heat boiler 4 to form a linkage regulation with the steam distribution device. A preset carbon content value (usually 5%) is set. When the value measured by the online carbon content sensor is higher than the preset value, the steam injection amount is increased (achieved by PID and other methods). When the increase in steam volume causes the dense phase zone (middle and lower part of the lower cone section) to drop below the preset temperature lower limit of the dense phase zone, the primary gasification agent supply is increased, and the step temperature regulation in the gasification chamber is achieved by a cascade regulation method combining steam volume and oxygen-enriched oxygen volume.

[0033] The secondary gasification agent distribution device includes a lower secondary gasification agent distribution nozzle 6 arranged at the upper part of the lower cone section 9 and an upper secondary gasification agent distribution nozzle 7 arranged at the upper part of the upper cone section. The tertiary gasification agent distribution device includes a tertiary gasification agent distribution nozzle arranged at the lower part of the upper straight section 2.

[0034] The inner wall structure of the upper straight section is as follows Figure 3 As shown, the special-shaped insulation bricks 1002 are arranged in a fitted manner near the membrane water-cooled wall 1001, and the standard refractory high-aluminum bricks 1003 are used to form a wear-resistant and heat-insulating high-aluminum refractory layer 10 near the inner side of the furnace, thereby preventing the upper straight section of the membrane water-cooled wall from absorbing heat, thereby providing conditions for the upper high-temperature gasification. Pins 1004 are also provided in the high-aluminum refractory layer 10, and their function is similar to that of the grabbing nails 903, mainly serving to fix the refractory layer (including insulation bricks and high-aluminum bricks).

[0035] The gasification raw material enters the gasification chamber through the feed port 12 from the feeding device, and the feed port 12 is usually arranged below the middle of the gasification chamber. After the gasification raw material completes oxygen-enriched gasification in the gasification chamber, the high-temperature gasification gas enters the connected waste heat boiler 4. The waste heat boiler 4 uses a return flue including a downward channel and an upward channel. The wall surface of the return flue uses a membrane water-cooled wall structure, which can absorb the heat of the gasification gas, reduce the temperature of the gasification gas, and recycle the waste heat. Furthermore, a convection heating surface 11 is provided in the upward channel of the waste heat boiler. An inertial separator is formed at the bottom of the downward channel and the upward channel. An ash hopper is provided at the bottom of the inertial separator. Due to the effect of inertia, the solid particles carried in the gasification gas will be inertially separated at the return point and collected by the ash hopper. As a preferred embodiment, an online carbon content sensor is provided in the ash hopper.

[0036] The temperature of the gasified gas after absorbing waste heat in the waste heat boiler 4 drops to 180-220° C. and enters the purification device 5 for further purification.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A TFB oxygen-enriched gasification chamber comprises a lower variable cross-section section (1) and an upper straight section (2), wherein the variable cross-section section (1) comprises, from bottom to top, a lower conical section (9), a transitional straight section and an upper conical section; a primary gasification agent distribution device is provided at the bottom of the lower conical section (9) for distributing oxygen-enriched gas as a primary gasification agent, and is characterized in that: The lower cone section (9) is made of a high thermal conductivity and wear-resistant wall surface, and the high thermal conductivity and wear-resistant wall surface comprises a sealing steel plate (901), a water-cooling pipe row (902), a silicon carbide refractory material layer (904) and a plurality of gripping nails (903), and the silicon carbide refractory material layer is made of a silicon carbide refractory material with a content of greater than or equal to 60%; the sealing steel plate (901) is arranged as the outer wall surface at the outermost layer, the silicon carbide refractory material layer (904) is arranged as the inner wall surface, and the water-cooling pipe row (902) is arranged on the silicon carbide refractory material layer. The silicon carbide refractory material layer is arranged near the sealing steel plate (901); the grabbing nails are buried in the silicon carbide refractory material layer, wherein a part of the grabbing nails are distributed between the water-cooling tube rows and one end of the grabbing nails is welded to the sealing steel plate, and one end of a part of the grabbing nails is welded to the outer wall surface of the water-cooling tube row; the transition straight section, the upper cone section and the upper straight section use membrane water-cooled wall surfaces, and the inner wall surface of the upper straight section is coated with a high-aluminum refractory layer; the water-cooling tube row of the lower cone section (9) is connected to the membrane water-cooled wall surface of the transition straight section through a header.

2. The TFB oxygen-enriched gasification chamber according to claim 1, characterized in that: The silicon carbide refractory material layer is made of silicon carbide refractory material with a content of greater than or equal to 85%.

3. The TFB oxygen-enriched gasification chamber according to claim 1, characterized in that: The primary gasification agent distribution device also includes a steam distribution device.

4. The TFB oxygen-enriched gasification chamber according to claim 1, characterized in that: The gasification chamber also includes a secondary gasification agent distribution device and a tertiary gasification agent distribution device, which can distribute oxygen-enriched oxygen as the secondary gasification agent and the tertiary gasification agent to form a staged gasification; the secondary gasification agent distribution device includes a lower secondary gasification agent distribution nozzle (6) arranged at the upper part of the lower cone section (9) and an upper secondary gasification agent distribution nozzle (7) arranged at the upper part of the upper cone section, and the tertiary gasification agent distribution device includes a tertiary gasification agent distribution nozzle arranged at the lower part of the upper straight section (2). 5.TFB oxygen-enriched gasifier, characterized in that: It comprises a gasification chamber as claimed in any one of claims 1 to 4, and a waste heat boiler (4) and a purification device (5) connected in sequence, wherein the waste heat boiler (4) uses a return flue comprising a descending channel and an ascending channel, and a gasification gas outlet is arranged on one side of the top of the gasification chamber and is connected to the descending channel inlet of the waste heat boiler (4).

6. The TFB oxygen-enriched gasification furnace according to claim 5, characterized in that: A convection heating surface (11) is provided in the upward passage of the waste heat boiler.

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