An internal component for gas diversion and cascaded heat transfer in a fixed-bed gasifier

Abstract

The present invention discloses an internal component for gas diversion and cascade heat transfer in a fixed-bed gasifier. The internal component for gas diversion and cascade heat transfer includes a cylindrical barrel with openings at both ends; the outer edge of the upper opening of the cylindrical barrel is connected to an upper top plate; the outer edge of the lower opening of the cylindrical barrel is connected to a lower bottom plate; a plurality of channels are provided on the lower bottom plate; when the internal component for gas diversion and cascade heat transfer is matched with the fixed-bed gasifier, the cylindrical barrel, the upper top plate, and the lower bottom plate form an annular channel with the fixed-bed gasifier, and the annular channel is communicated with a lower-stage gas outlet provided on the fixed-bed gasifier; an upper-stage gas outlet on the fixed-bed gasifier is provided above the internal component for gas diversion and cascade heat transfer. The internal component of the present invention can reduce the dust entrainment of the upper-stage gas, improve the quality of tar, and reduce the output of difficult-to-treat wastewater; the internal component has a gas-solid separation effect, better reduces the dust entrainment of the lower-stage gas, and relieves the pressure on the subsequent gas purification system.

Description

Technical Field

[0001] The present invention relates to an internal component for gas diversion and cascade heat transfer in a fixed-bed gasifier, belonging to the technical field of coal chemical industry. Background Art

[0002] Coal gasification is a key way to realize the efficient and clean utilization of coal. The fixed-bed gasification technology is one of the three important gasification technologies and has a wide market application prospect.

[0003] Traditional fixed-bed gasifiers adopt a single-stage gas outlet mode. All the gas generated by gasification contacts the coal countercurrently from bottom to top, successively passing through the ash layer, oxidation layer, gasification reduction layer, dry distillation layer and drying layer, and discharging from the gas outlet. The gas has high heat and large flow velocity, resulting in a high temperature in the dry distillation layer, a large amount of dust entrainment in the gas, a reduction in the tar yield, an increase in the dust content in the tar, and a large output of phenol-containing wastewater. There are generally problems in traditional pyrolysis, such as difficult energy recovery of hot semicoke, large heat loss in coke quenching, poor quality of semicoke, easy pulverization of the semicoke when leaving the furnace and difficult reuse. Chinese Patent Application CN107892952 A discloses a two-stage slag gasifier, in which an optimized heat transfer internal component arranged along the axial direction of the cylinder body is provided. Although the above defects of the traditional fixed-bed gasifier are improved to a certain extent, since a gas-solid separation device is not provided in the annular space between the internal component and the gasifier cylinder body, the gas flow velocity in the lower-stage gas is still relatively large, and a small amount of coal dust still exists in the gas discharged from the lower-stage outlet. Summary of the Invention

[0004] The purpose of the present invention is to provide an internal component for gas diversion and cascade heat transfer in a fixed-bed gasifier, which can reduce the dust entrainment of fixed-bed gas, improve the quality of tar, reduce the output of difficult-to-treat wastewater, and thus realize coal pyrolysis and semicoke gasification in the same device.

[0005] The internal component for gas diversion and cascade heat transfer in the fixed-bed gasifier provided by the present invention includes a cylindrical cylinder body with openings at both ends;

[0006] The outer edge of the upper opening of the cylindrical cylinder body is connected to the upper top plate;

[0007] The outer edge of the lower opening of the cylindrical cylinder body is connected to the lower bottom plate;

[0008] A plurality of channels are provided on the lower bottom plate;

[0009] The upper top plate is a closed plate;

[0010] When the internal component for gas diversion and cascade heat transfer cooperates with the fixed-bed gasifier, the cylindrical cylinder body, the upper top plate, the lower bottom plate and the fixed-bed gasifier form an annular channel, and the annular channel is communicated with the lower-stage gas outlet provided on the fixed-bed gasifier;

[0011] The upper gas outlet on the fixed-bed gasifier is arranged at the upper part of the gas guiding and stepped heat transfer internal component;

[0012] The inner cavity of the cylindrical barrel serves as the central channel.

[0013] In the above-mentioned gas guiding and stepped heat transfer internal component, one surface or two surfaces of the cylindrical barrel, the upper top plate and the lower bottom plate are coated with refractory materials;

[0014] The refractory material can be silicon carbide (SiC) refractory material, alumina refractory material, magnesia refractory material, corundum refractory, corundum hollow ball, heat-insulating refractory or composite material, etc.

[0015] In the above-mentioned gas guiding and stepped heat transfer internal component, the included angle α between the upper top plate and the outer wall of the cylindrical barrel is 0 to 180°, but not 0° or 180°;

[0016] Preferably, the included angle between the upper top plate and the outer wall of the cylindrical barrel is 120° to 150°; this included angle range is beneficial for the lower-stage gasified gas in the annular channel to be exported from the gasifier through the lower gas outlet, and is also beneficial for the raw coal added from the top of the fixed-bed gasifier body to enter the bottom of the gasifier evenly and smoothly for gasification reaction.

[0017] In the above-mentioned gas guiding and stepped heat transfer internal component, the included angle β between the lower bottom plate and the outer wall of the cylindrical barrel is 0° to 180°, but not 0° or 180°.

[0018] Preferably, the included angle between the lower bottom plate and the outer wall of the cylindrical barrel is 120° to 150°; this included angle range is beneficial for the gasified gas generated in the central channel of the fixed-bed gasifier body to enter the annular channel through the pore channels arranged on the upper surface of the lower bottom plate, and then be exported from the gasifier through the lower gas outlet.

[0019] In the above-mentioned gas guiding and stepped heat transfer internal component, the inner diameter of the pore channel is 1 mm to 20 mm;

[0020] The pore channel plays a guiding role in enabling the gasified gas generated in the central channel of the fixed-bed gasifier body to enter the annular channel, and then be exported from the gasifier through the lower gas outlet.

[0021] The gas diversion and cascade heat transfer internal component of the present invention is made of metal materials such as copper, Inconel600, 310 stainless steel, etc. From top to bottom, the specific heat of the metal material increases from top to bottom, achieving the effect of cascade heat transfer, keeping the temperature of the internal component consistent, improving the yield and quality of gas and tar, and better transferring heat back to the furnace body by using the internal component instead of wasting it with the discharged gas. Moreover, the materials of each section of the internal component have different thermal conductivities, so the heat transfer between gas and coal can be optimized.

[0022] The fixed bed gasifier formed by the cooperation of the gas diversion and cascade heat transfer internal component of the present invention and the fixed bed gasifier body also belongs to the protection scope of the present invention.

[0023] By setting a gas-solid separation internal component in the fixed bed gasifier, the present invention realizes the simultaneous pyrolysis of coal and gasification of semi-coke in the same device. The gasified gas in the lower section and the pyrolysis gas in the upper section are exported in sections and exchanged heat in a cascade manner. While not reducing the gasification intensity and gasification efficiency, the tar yield is increased by controlling the temperature of the pyrolysis section and the gas flow rate, realizing efficient co-production of oil and gas. The internal component of the present invention can reduce the entrainment of gas dust in the upper section, improve the quality of tar, and reduce the production of difficult-to-treat wastewater; this internal component has a gas-solid separation effect, better reducing the entrainment of gas dust in the lower section and reducing the pressure of the subsequent gas purification system. Brief Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of the gas diversion and cascade heat transfer internal component of the fixed bed gasifier of the present invention.

[0025] Figure 2 It is a schematic diagram of the metal skeleton of the gas diversion and cascade heat transfer internal component of the fixed bed gasifier of the present invention.

[0026] Figure 3 It is a schematic diagram of the upper top plate of the gas diversion and cascade heat transfer internal component of the fixed bed gasifier of the present invention.

[0027] Figure 4 It is a schematic diagram of the lower bottom plate of the gas diversion and cascade heat transfer internal component of the fixed bed gasifier of the present invention.

[0028] Figure 5 It is a schematic diagram when the gas diversion and cascade heat transfer internal component of the fixed bed gasifier of the present invention is combined with the gasifier.

[0029] The marks in the figure are as follows:

[0030] 1 Fixed bed gasifier body, 2 Upper section gas outlet, 3 Lower section gas outlet, 4 Cylindrical barrel, 5 Annular channel, 6 Central channel, 7 Lower bottom plate, 8 Channel, 9 Baffle, 10 Upper top plate, 11 Metal skeleton, 11A, 11B, 11C Metals of different materials, 12 Refractory material. Detailed Description of the Invention

[0031] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0032] As Figure 1 shown, the inner component of the gasifier provided by the present invention includes a cylindrical barrel body 4 with openings at both ends. The outer edge of the upper opening of the cylindrical barrel body 4 is connected to the upper top plate 10, and the upper top plate 10 is a closed plate, as Figure 3 shown. The outer edge of the lower opening of the cylindrical barrel body 4 is connected to the lower bottom plate 7. A plurality of channels 8 are provided on the lower bottom plate 7. Outside the channels 8 is a baffle 9, which reduces the gas flow velocity of the lower-stage gas and blocks most of the dust in the gas from entering the annular channel 5, thereby reducing the dust content in the lower-stage gas and playing a role in gas-solid separation and flow guiding, as Figure 4 shown. The inner diameter of the channels 8 is 1 mm to 20 mm, which enables the gasified gas generated in the central channel 6 of the gasifier 1 to enter the annular channel 5 and then be led out of the gasifier through the lower-stage gas outlet 3.

[0033] As Figure 5 shown, it is a schematic diagram of the cooperation between the inner component of the gasifier of the present invention and the fixed-bed gasifier. The cylindrical barrel body 4, the upper top plate 10, and the lower bottom plate 7 form an annular channel 5 with the fixed-bed gasifier body 1, and the annular channel 5 is communicated with the lower-stage gas outlet 3 provided on the fixed-bed gasifier body; the inner cavity of the cylindrical barrel 4 serves as the central channel 6, and the upper-stage gas outlet 2 on the fixed-bed gasifier body 1 is provided above the inner component of the fixed-bed gasifier, that is, the central channel 6 is communicated with the upper-stage gas outlet 2.

[0034] In order to protect the metal skeleton 11 of the inner component, one surface or two surfaces of the cylindrical barrel body 4, the upper top plate 10, and the lower bottom plate 7 of the inner component are coated with refractory materials 12. The refractory materials can be silicon carbide (SiC) refractory materials, alumina refractory materials, magnesia refractory materials, or composite materials, etc. The cylindrical barrel body 4, the upper top plate 10, and the lower bottom plate 7 are all made of metal materials, such as Figure 1 the metal skeleton 11 shown. As Figure 2 shown, from top to bottom, the metal skeleton 11 adopts metal materials (11A, 11B, 11C) with different specific heats, such as copper, Inconel600, 310 stainless steel, etc., to achieve the stepped heat transfer of the inner component.

[0035] As Figure 1As shown in the figure, to facilitate the export of the gasified gas in the middle and lower sections of the annular channel 5 from the lower gas outlet 3 of the gasifier, to facilitate the uniform and smooth entry of the raw coal added from the top of the fixed-bed gasifier body 1 into the bottom of the gasifier for gasification reaction, and to facilitate the gasified gas generated in the central channel 6 of the fixed-bed gasifier body 1 to enter the annular channel 5 through the pore channels 8 arranged on the upper surface of the lower bottom plate 7, and then be exported from the gasifier through the lower gas outlet 3, the included angle between the upper top plate 10 and the outer wall of the cylindrical barrel 4 is 0 to 180°, but not 0° or 180°, preferably 120° to 150°; the included angle between the lower bottom plate 7 and the outer wall of the cylindrical barrel 4 is 0° to 180°, but not 0° or 180°, preferably 120° to 150°.

[0036] When using the internal components of the gasifier of the present invention, as Figure 5 shown, the internal components of the gasifier are arranged in the fixed-bed gasifier body 1. The raw coal and the gasifying agent undergo a gasification reaction in the lower part of the fixed-bed gasifier body 1. A part of the gas generated by the gasification reaction enters the central channel 6, passes through the dry distillation zone and the drying zone of the gasifier, and the sensible heat contained in the gas is directly transferred to the coal seam, causing the coal seam to undergo dry distillation and drying. The gas after heat exchange is discharged from the gasifier through the upper gas outlet 2. Since the upper gas passes through the dry distillation zone, the upper gas is rich in hydrogen and a certain amount of tar. Because only a part of the gas generated by the gasification reaction enters the central channel 6, the flow rate and velocity of the upper gas are reduced, the dust entrainment of the gas is reduced, the tar dust content is low, and the quality of the tar is improved. At the same time, due to the reduction in the flow rate of the upper gas, the amount of difficult-to-treat wastewater generated by the cooling of the gas is reduced. Another part of the gas generated by the gasification reaction enters the annular channel 5 through the pore channels 8 on the lower bottom plate 7 of the internal components of the gasifier. The sensible heat contained in the gas is indirectly transferred to the coal seam in the gasifier by the stepped heat transfer internal components of the gasifier. The gas after heat exchange is discharged from the gasifier through the lower gas outlet 3. The lower gas is the gas generated in the gasification section, almost free of tar, and the dust is removed through the gas-solid separation function of the lower bottom plate of the internal components of the gasifier, and the gas dust content is extremely low.

[0037] Application example:

[0038] The working pressure of the gasifier is 4.0 MPa, the raw material processing capacity is 208 kg / h, the oxygen inlet flow rate is 66 Nm 3 / h, the inner diameter of the furnace body is 500 mm, the thickness of the furnace body is 50 mm, the material of the gasifier is Q345R, and the effective height of the gasifier is 5100 mm. Among the internal components, the inner diameter is 400 mm, the thickness is 10 mm, the height is 1650 mm, and the metal skeleton material is copper, Inconel600, and stainless steel 310 from top to bottom. Among them, the density of copper is 8978 kg / m 3 、specific heat is 390 J / (kg·k), the density of Inconel600 is 8400 kg / m 3, the specific heat is 444 J / (kg·k), and the density of 310 stainless steel is 7930 kg / m 3 , the specific heat is 502 J / (kg·k). The outer surface and the inner surface of the internal component metal skeleton are coated with refractory materials to protect the metal skeleton. The specific heat increases from top to bottom, so that the temperature of the stepped heat transfer internal component remains consistent, improving the yield and quality of gas and tar. The internal component can better transfer heat back into the furnace body instead of being wasted by discharging with the gas. Moreover, the materials of each section of the internal component have different thermal conductivities, so the heat transfer between the gas and the coal can be optimized. The syngas of the gasifier has upper-stage outlet gas and lower-stage outlet gas. Under such conditions, the optimization of the gasification products and the construction economy are taken into account, and the stepped heat transfer in the furnace is achieved at the same time, making good use of the heat exchange between the gas and the coal. By adding this internal component, the light component of tar in the fixed-bed gasifier is increased by 6%, the dust content is reduced by 30%, and the waste water volume is reduced by 60%.

Claims

1. A gas guiding and cascaded heat transfer internal component for a fixed bed gasifier, characterized in that: It includes a cylindrical tube body with openings at both ends; The outer edge of the upper opening of the cylindrical tube body is connected to the upper top plate; The outer edge of the lower opening of the cylindrical tube body is connected to the lower bottom plate; A number of channels are provided on the lower bottom plate; When the gas guiding and stepped heat transfer internal component is matched with the fixed bed gasifier, the cylindrical tube body, the upper top plate, the lower bottom plate and the fixed bed gasifier form an annular channel, and the annular channel is communicated with the lower stage gas outlet provided on the fixed bed gasifier; The upper stage gas outlet on the fixed bed gasifier is provided above the gas guiding and stepped heat transfer internal component; The included angle between the upper top plate and the outer wall of the cylindrical tube body is 120° - 150°; The included angle between the lower bottom plate and the outer wall of the cylindrical tube body is 120° - 150°; The gas guiding and stepped heat transfer internal component is made of metal material, and from top to bottom, the specific heat of the metal material increases.

2. The gas diversion and cascade heat transfer internal component according to claim 1, wherein: One surface or two surfaces of the cylindrical tube body, the upper top plate and the lower bottom plate are coated with refractory materials.

3. The gas flow guiding and cascade heat transfer internal component according to claim 1 or 2, characterized in that: The inner diameter of the channel is 1mm - 20mm.

4. A fixed-bed gasifier, characterized in that: It includes a fixed bed gasifier body and the gas guiding and stepped heat transfer internal component according to any one of claims 1 - 3 provided in the fixed bed gasifier body.

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