Fluidized bed biomass gasifier with refractory furnace wall

Abstract

The utility model discloses a kind of fire-resistant furnace wall for fluidized bed type biomass gasification furnace, including the composite furnace wall body that by inner layer is refractory brick body layer and outer layer is light heat insulation layer, multiple circumferential setting on the protective plate assembly of refractory brick body layer inner wall and multiple circumferential setting on the memory alloy of the cavity of light heat insulation layer any side wall;The device is through memory alloy high-temperature contraction to pull protective plate close to furnace body inner wall, form dynamic sealing barrier, effectively offset the stress concentration caused by the difference of refractory brick body and metal furnace shell thermal expansion coefficient, avoid the penetrating crack caused by thermal stress of traditional integral pouring structure;Reset protective plate when low-temperature extension, provide buffer space for thermal expansion release, reduce structural damage risk;Protective plate is slid with slide groove by slide bar, always close to furnace wall under high temperature, block high-speed particles directly impact refractory brick body joint, reduce ash joint material abrasion and loose;The assembly type design of slide groove and slide bar is convenient for independent disassembly and replacement maintenance of protective plate assembly.

Description

Technical Field

[0001] This utility model relates to the field of refractory furnace wall technology, specifically to a refractory furnace wall for a fluidized bed biomass gasification furnace. Background Technology

[0002] The refractory walls of fluidized bed biomass gasifiers must maintain structural integrity and airtightness under high temperature, dynamic particle erosion, and complex thermo-coupling environments. Their structural design must meet the requirements of reasonable configuration to disperse or absorb thermal stress generated by temperature gradients, thereby preventing wall cracking. They also need to achieve dynamic sealing under conditions of intense gas-solid two-phase movement to prevent gas leakage and particle penetration through wall gaps, resist the continuous erosion and collision of high-speed flowing solid particles within the bed, and support modular maintenance for rapid component replacement in case of localized damage, reducing downtime.

[0003] Early refractory furnace walls mostly adopted monolithic cast-in-place or single-layer masonry designs, but these had significant drawbacks. While monolithic cast-in-place structures offered better sealing, the difference in thermal expansion coefficients between the material and the metal furnace shell led to thermal stress concentration, making them highly susceptible to penetrating cracks and ultimately resulting in loss of airtightness. Furthermore, localized damage to such structures often necessitated complete demolition, making them uneconomical.

[0004] While single-layer masonry structures, which splice refractory bricks with mortar joints, can partially alleviate the problem of thermal expansion, the mortar joint material is prone to failure under thermal shock conditions, leading to loosening or even detachment of the bricks. Especially in the high particle velocity region of a fluidized bed, solid particles will directly impact the brick joints, accelerating wear and widening the gaps, further weakening the structural stability. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model provides a refractory furnace wall for a fluidized bed biomass gasification furnace.

[0006] The technical solution of this utility model is a refractory furnace wall for a fluidized bed biomass gasification furnace: it includes a composite furnace wall body composed of an inner layer of refractory bricks and an outer layer of lightweight insulation, multiple protective plate assemblies arranged circumferentially on the inner wall of the refractory bricks, and multiple shape memory alloys arranged circumferentially on any side wall of the cavity inside the lightweight insulation layer.

[0007] The composite furnace wall body has two layers: an inner layer of refractory bricks and an outer layer of lightweight insulation. The refractory brick layer is composed of multiple bricks arranged circumferentially. The bricks are provided with through grooves.

[0008] The protective plate assembly includes multiple protective plates circumferentially arranged on the inner wall of the refractory brick layer. The shape memory alloy is provided with a sliding rod for pulling by the thermal contraction of the shape memory alloy. The sliding rod passes through the lightweight insulation layer and the refractory brick layer in sequence and is fixedly connected to the protective plate.

[0009] Explanation: The double-layer structure of the composite furnace wall body, namely the refractory brick layer and the lightweight insulation layer, takes into account both mechanical strength and thermal insulation performance, reducing heat loss while lowering the furnace shell temperature; the phase transformation temperature of the shape memory alloy is precisely matched with the furnace operating conditions, combining long cycle life and high reliability, significantly reducing drive energy consumption.

[0010] Furthermore, the protective plate is a silicon nitride-bonded silicon carbide plate, the brick body is a corundum-silicon carbide composite brick; the slide rod is made of reaction-sintered silicon carbide, and a graphite lubrication layer is provided on the inner wall of the slide groove; the lightweight heat insulation layer is made of ceramic fiber reinforced lightweight castable; the shape memory alloy is a bent sheet or spring, and its material is a Fe-Mn-Si-Cr-Nb pentagonal alloy.

[0011] Explanation: The low-friction fit between the graphite lubrication layer on the inner wall of the chute and the reaction-bonded silicon carbide slide bar ensures smooth movement of the protective plate and avoids high-temperature jamming; the silicon nitride-bonded silicon carbide plate has both high hardness and thermal shock resistance, effectively resisting the impact and wear of high-speed particles in the fluidized bed; the corundum-silicon carbide composite brick enhances the mechanical silicon carbide composition through the corundum skeleton, thereby increasing the resistance to chemical corrosion and significantly extending the overall life of the furnace wall; the ceramic fiber reinforced structure improves compressive strength while ensuring thermal insulation performance, reducing heat loss from the furnace shell and lowering its surface temperature to a safe range; the Fe-Mn-Si-Cr-Nb alloy phase transformation temperature is precisely adapted to the fluidized bed conditions, with high high-temperature shrinkage tension, low-temperature extension and reset error of less than 0.5mm, and a cycle life of more than 5000 cycles, achieving stable drive.

[0012] Furthermore, a gap is left between the refractory brick layer and the lightweight insulation layer. A self-healing agent release component is provided in the cavity on one side of the shape memory alloy. The self-healing agent release component includes a repair agent spray can and a lever plate disposed on one side of the shape memory alloy for squeezing the repair agent spray can. The nozzle of the repair agent spray can is connected to a valve hole on the surface of the protective plate through a pipeline. A supply pipe is also provided on the repair agent spray can, and pressure valves are provided on both the nozzle and the supply pipe.

[0013] Note: Using a pressure control valve to spray the repair agent can prevent pipeline blockage and improve system reliability. A supply pipe ensures a continuous supply of repair agent.

[0014] Furthermore, the repair agent spray can is filled with aluminum phosphate-zirconia-based high-temperature putty, which is normally a solid powder, and the repair agent spray can is sealed with nitrogen gas.

[0015] Note: The aluminum phosphate-zirconia putty melts into a glassy glaze layer when heated to a melting point of 1200℃, repairing micro-cracks and improving thermal uniformity; nitrogen sealing prevents the putty from oxidizing and failing at high temperatures, ensuring storage safety.

[0016] Furthermore, the valve orifice is distributed into multiple outlets, which are arranged laterally along the surface of the protective plate, and the inner wall of the outlet is coated with a yttrium-stabilized zirconia coating.

[0017] Note: The valve orifice is divided into multiple outlets, which are arranged laterally along the surface of the protective plate to improve the uniformity of powder dispersion; the zirconia coating is heat resistant to 1500℃ to prevent flow deviation caused by high temperature deformation of the orifice wall.

[0018] Furthermore, the protective plate has a honeycomb-shaped guide groove at the valve hole outlet for uniformly dispersing the repair agent.

[0019] Description: The honeycomb guide channel evenly disperses the sprayed repair agent, increases the coverage area, and eliminates repair blind spots; the guide channel has a simple structure with no moving parts and can withstand the impact of high-temperature particles.

[0020] The beneficial effects of this utility model are:

[0021] This device significantly improves the structural stability and sealing reliability of refractory furnace walls under high temperature, dynamic scouring, and thermal cycling conditions through the synergistic effect of the composite furnace wall body, protective plate assembly, and shape memory alloy. The shape memory alloy deforms based on temperature changes. When it contracts at high temperatures, it pulls the protective plate tightly against the inner wall of the furnace, forming a dynamic sealing barrier. This effectively counteracts stress concentration caused by the difference in thermal expansion coefficients between the refractory bricks and the metal furnace shell, avoiding through-cracks caused by thermal stress in traditional monolithic cast structures. When it expands at low temperatures, the protective plate resets, providing a buffer space for thermal expansion and reducing the risk of structural damage. The protective plate, through the sliding fit of the sliding rod and the sliding groove, remains tightly fitted to the furnace wall at high temperatures, preventing high-speed particles from directly impacting the joints of the refractory bricks and reducing wear and loosening of the mortar joint material. The modular design of the sliding groove and the sliding rod allows for independent replacement of the protective plate assembly. In case of partial damage, the entire furnace wall does not need to be removed, significantly shortening the maintenance cycle and reducing downtime losses. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this utility model;

[0023] Figure 2 This is a schematic diagram of the cavity structure of Embodiment 1 of this utility model;

[0024] Figure 3 This is a schematic diagram of the structure of the brick, sliding rod, and shape memory alloy in Embodiment 1 of this utility model;

[0025] Figure 4 This is a partial schematic diagram of the protective plate and shape memory alloy of Embodiment 1 of this utility model;

[0026] Figure 5 This is a longitudinal sectional view of the self-healing agent release component of Embodiment 2 of this utility model;

[0027] Figure 6 This is a schematic diagram of the connection between the dial plate and the shape memory alloy in Embodiment 2 of this utility model;

[0028] Figure 7 This is a transverse sectional view of the interior of the lightweight insulation layer in Embodiment 2 of this utility model;

[0029] Figure 8 This is a schematic diagram of the valve orifice outlet distribution in Embodiment 3 of this utility model;

[0030] Figure 9 This is a cross-sectional view of the valve hole inside the protective plate of Embodiment 3 of this utility model;

[0031] Among them, 1-composite furnace wall body, 11-refractory brick body layer, 12-lightweight heat insulation layer, 111-slide groove, 2-protective plate assembly, 21-protective plate, 22-slide rod, 3-shape memory alloy, 4-self-healing agent release assembly, 41-repair agent spray can, 411-nozzle, 412-replenishment pipe, 42-paddle plate. Detailed Implementation

[0032] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0033] Example 1: As Figures 1-4 The refractory furnace wall for a fluidized bed biomass gasifier shown includes a composite furnace wall body 1 composed of an inner refractory brick layer 11 and an outer lightweight insulation layer 12, a protective plate assembly 2 circumferentially disposed on the inner wall of the refractory brick layer 11, and a plurality of shape memory alloys 3 circumferentially disposed on the side wall of the cavity inside the lightweight insulation layer 12 away from the center of the furnace body.

[0034] like Figure 1 , 2 As shown, the composite furnace wall body 1 has two layers: an inner layer of refractory bricks 11 and an outer layer of lightweight insulation 12. The refractory bricks 11 is composed of multiple bricks arranged circumferentially and constructed. The bricks are provided with through grooves 111.

[0035] The protective plate assembly 2 includes seventeen protective plates 21 circumferentially arranged on the inner wall of the refractory brick layer 11. The shape memory alloy 3 is provided with a sliding rod 22 for pulling by the heat shrinkage of the shape memory alloy 3. The sliding rod 22 passes through the lightweight heat insulation layer 12 and the refractory brick layer 11 in sequence and is fixedly connected to the protective plate 21.

[0036] like Figure 2 , 4As shown, the shape memory alloy 3 is disposed in the cavity 13 within the lightweight insulation layer 12, with one end fixedly connected to the inner wall of the lightweight insulation layer 12 and the other end fixedly connected to the end of the slide rod 22; the shape memory alloy 3 contracts and pulls the protective plate 21 to fit tightly against the inner wall of the furnace at high temperatures, and extends and resets at low temperatures;

[0037] The protective plate 21 is made of silicon nitride-bonded silicon carbide plate produced by Jiaozuo Shiheng Refractory Materials Co., Ltd., and the brick body is made of RTT-SC70A corundum-silicon carbide composite brick produced by Ruitai Technology Co., Ltd.; the slide rod 22 is made of reaction sintered silicon carbide tube produced by Yixing Haidun Precision Ceramics Co., Ltd., and a graphite lubrication layer is provided on the inner wall of the slide groove 111. The graphite lubrication layer is made of flexible graphite plate produced by Qingdao Chijiu High-tech Materials Co., Ltd., and the friction coefficient between the slide rod and the slide groove is less than or equal to 0.1; the lightweight heat insulation layer 12 is made of ceramic fiber lightweight refractory castable produced by Langfang Hengcheng Insulation Materials Co., Ltd.; the shape memory alloy 3 is a V-shaped bent sheet, and its material is a Fe-Mn-Si-Cr-Nb pentagonal alloy.

[0038] The working principle of this embodiment is as follows: In this embodiment, when the fluidized bed biomass gasifier is running, the furnace temperature rises to 800–1000℃. The curved sheet-like shape memory alloy 3 made of Fe-Mn-Si-Cr-Nb pentagonal alloy undergoes a phase transformation and shrinks upon heating. This shrinkage is caused by the sliding rod 22 pulling the protective plate 21 along the sliding groove 111 towards the inner wall of the furnace, so that the protective plate is tightly attached to the inner wall to form a dynamic seal. This not only buffers the impact of particulate matter but also resists the scouring of the gas-solid two-phase flow and blocks gas leakage. After the furnace is shut down and cooled, the temperature drops below 200℃, and the shape memory alloy returns to its initial shape and stretches, pushing the protective plate back to its initial position, releasing thermal stress and providing operating space for maintenance and replacement. The graphite lubricating layer between the sliding rod 22 and the sliding groove 111 ensures smooth sliding. The sliding rod, made of reaction-sintered silicon carbide material, has a thermal expansion coefficient that matches that of the corundum-silicon carbide composite brick, which is close to 4.5 × 10⁻⁶. -6 / ℃, to avoid high temperature stagnation; the ceramic fiber reinforced castable of the lightweight heat insulation layer 12 controls the temperature of the cavity 13 below 800℃, ensuring the stable phase change cycle of the shape memory alloy.

[0039] Example 2: As Figures 5-7As shown, this embodiment differs from Embodiment 1 in that a gap is left between the refractory brick layer 11 and the lightweight insulation layer 12, and a self-healing agent release component 4 is provided in the cavity on one side of the shape memory alloy 3. The self-healing agent release component 4 includes a repair agent spray can 41 and a lever 42 disposed on one side of the shape memory alloy 3 for squeezing the repair agent spray can 41; the nozzle 411 of the repair agent spray can 41 is connected to the valve hole on the surface of the protective plate 21 through a pipe embedded in the slide rod 22; a supply pipe 412 is also provided on the repair agent spray can 41, and the nozzle 411 and the supply pipe Pressure valves are provided on each of the nozzles 412; the pressure valve of the nozzle 411 is a one-way pressure valve that opens from the inside to the outside of the repair agent spray can 41, and the pressure valve of the supply pipe is a one-way pressure valve that opens from the outside to the inside of the repair agent spray can 41. The supply pipe is embedded and passes through the lightweight insulation layer 12 and is connected to the external repair agent supply can. The repair agent spray can 41 can be stretched and contracted laterally. The repair agent spray can 41 is filled with nitrogen gas for sealing. The repair agent spray can 41 is filled with AlPO4-ZrO2 putty, which uses RT-HM1200P putty produced by Gongyi Ruitai Refractory Materials Co., Ltd., and is normally a solid powder.

[0040] The working principle of this embodiment is as follows: When the furnace temperature rises to 800–1000℃, the V-shaped memory alloy 3 made of Fe-Mn-Si-Cr-Nb pentagonal alloy undergoes a phase transformation and shrinks upon heating, which drives the push plate to squeeze the repair agent spray can 41. The pressure valve of the nozzle 411 opens, and powdered self-healing agent is sprayed onto the surface of the protective plate 21 through the pipeline. The powder flows and spreads along the surface of the protective plate. After the furnace temperature continues to rise to the melting point of 1200℃, it melts into a glassy glaze layer. When the furnace temperature drops to below 200℃, the memory alloy returns to its initial shape and stretches. The repair agent spray can 41 returns to the stretched state. At this time, the pressure valve of the nozzle 411 closes and the pressure valve of the supply pipe opens. The external repair agent supply can replenishes and fills the repair agent spray can 41 with repair agent.

[0041] Example 3: This example differs from Example 1 in that, as Figure 8 , 9 As shown, the valve hole is divided into multiple outlets, which are arranged laterally along the surface of the protective plate 21. The inner wall of the outlet is coated with a yttrium-stabilized zirconia coating with a thickness of 300 μm.

[0042] Example 4: The difference between this example and Example 1 is that the protective plate 21 has a honeycomb-shaped guide groove at the valve hole outlet for uniformly dispersing the repair agent.

Claims

1. A refractory furnace wall for a fluidized bed biomass gasification furnace, characterized in that, The furnace wall body (1) consists of a composite furnace wall body (1) with an inner layer of refractory brick (11) and an outer layer of lightweight insulation (12), a plurality of protective plate assemblies (2) arranged circumferentially on the inner wall of the refractory brick (11), and a plurality of shape memory alloys (3) arranged circumferentially on any side wall of the cavity inside the lightweight insulation (12); the refractory brick (11) is composed of a plurality of bricks arranged circumferentially; the bricks are provided with through grooves (111); the protective plate assembly (2) includes a plurality of protective plates (21) arranged circumferentially on the inner wall of the refractory brick (11), and the shape memory alloy (3) is provided with a sliding rod (22) for pulling by the heat shrinkage of the shape memory alloy (3), the sliding rod (22) passes through the lightweight insulation (12), the refractory brick (11) and is fixedly connected to the protective plate (21).

2. The refractory wall for a fluidized bed biomass gasifier according to claim 1, characterized in that, The protective plate (21) is a silicon nitride bonded silicon carbide plate, and the brick body is a corundum-silicon carbide composite brick; the slide rod (22) is made of reaction sintered silicon carbide, and a graphite lubrication layer is provided on the inner wall of the slide groove (111); the lightweight heat insulation layer (12) is made of ceramic fiber reinforced lightweight castable; the shape memory alloy (3) is a bent sheet or spring, and its material is a Fe-Mn-Si-Cr-Nb pentagonal alloy.

3. The refractory wall for a fluidized bed biomass gasifier according to claim 1, characterized in that, A gap is left between the refractory brick layer (11) and the lightweight insulation layer (12). A self-healing agent release component (4) is provided in the cavity on one side of the shape memory alloy (3). The self-healing agent release component (4) includes a repair agent spray can (41) and a lever (42) disposed on one side of the shape memory alloy (3) for squeezing the repair agent spray can (41). The nozzle (411) of the repair agent spray can (41) is connected to the valve hole on the surface of the protective plate (21) through a pipeline. A supply pipe (412) is also provided on the repair agent spray can (41). A pressure valve is provided on both the nozzle (411) and the supply pipe (412).

4. The refractory wall for a fluidized bed biomass gasifier according to claim 3, characterized in that, The repair agent spray can (41) is filled with aluminum phosphate-zirconia-based high-temperature putty, and the repair agent spray can (41) is sealed with nitrogen.

5. A refractory wall for a fluidized bed biomass gasifier according to claim 3, characterized in that, The valve hole is divided into multiple outlets, which are arranged laterally along the surface of the protective plate (21). The inner wall of the outlet is coated with yttrium oxide stabilized zirconia.

6. The refractory wall for a fluidized bed biomass gasifier according to claim 3, characterized in that, The protective plate (21) has multiple sets of valve holes distributed on its surface, and each set of valve holes has a honeycomb-shaped guide groove at its outlet for uniformly dispersing the repair agent.

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