Staged non-slag fixed bed gasifier

Abstract

The utility model discloses a graded non-slag fixed bed gasifier, which comprises: a pressure-bearing shell, the top of which is provided with a material inlet, the bottom of which is provided with a slag outlet, the pressure-bearing shell is provided with a gasifying agent inlet, and the upper part of the side wall of the pressure-bearing shell is provided with a first synthesis gas outlet; the fire grate is arranged at the lower part of the pressure-bearing shell, air outlet holes in the radial 0.7-0.8 D of the fire grate are central channels, the rest air outlet holes are edge channels, and the ratio of the total sectional area of the air outlet holes in the central channels to the total sectional area of the air outlet holes in the edge channels is (2-3): 1. The ratio of the center channel to the edge channel in the fire grate is changed, the ventilation capacity of the center channel of the fire grate is increased, the flame height of the fire grate is increased, and then the height of a gasification bed layer in a hearth and the handling capacity of raw materials are increased.

Description

Technical Field

[0001] The present invention relates to the technical field of carbonaceous material gasification, and more particularly to a graded non-slag fixed-bed gasifier. Background Art

[0002] The design concept of the grate in a traditional pressurized fixed-bed gasifier is to uniformly distribute the gasifying agent and form a uniform gasification gas flow field within the coal seam, allowing the gasification reaction in the feedstock layer to proceed fully. During operation, the grate ensures uniform gas discharge, and the axial height of each bed layer within the furnace is essentially constant. Given a fixed gasifier diameter, this affects feedstock handling. Summary of the Invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] Another object of the present invention is to provide a graded non-slag fixed bed gasification furnace, which increases the ventilation volume of the central channel of the grate and the flame height of the grate by changing the ratio of the central channel to the edge channel in the grate, thereby increasing the height of the gasification bed in the furnace and the processing capacity of raw materials.

[0005] In order to achieve these objects and other advantages of the present invention, a staged non-slag fixed bed gasifier is provided, comprising:

[0006] A pressure shell is provided with a material inlet at the top and a slag outlet at the bottom, a gasifying agent inlet at the pressure shell, and a first synthesis gas outlet at the upper portion of the side wall of the pressure shell;

[0007] The grate is arranged at the lower part of the pressure-bearing shell. The air outlet holes within the radial direction of 0.7-0.8D of the grate are central channels, and the remaining air outlet holes are edge channels. The ratio of the total cross-sectional area of the air outlet holes in the central channel to the total cross-sectional area of the air outlet holes in the edge channels is 2~3:1.

[0008] Preferably, the inner wall of the pressure-bearing shell is provided with a heat insulation layer, and the heat insulation layer is a membrane water-cooled wall structure or a water jacket structure.

[0009] Preferably, the gasifying agent inlet includes a main steam port and an auxiliary steam port, the main steam port is arranged at the bottom of the pressure shell and is connected to the grate, the auxiliary steam port is arranged on the side wall of the pressure shell, and the auxiliary steam port is located on one side inside the pressure shell and is connected to a gasifying agent distributor.

[0010] Preferably, the ratio of the distance between the gasifying agent distributor and the top of the grate to the diameter of the grate is 0.5-1.5:1.

[0011] Preferably, the air intake of the auxiliary steam port accounts for 10-30% of the total air volume.

[0012] Preferably, a second synthesis gas outlet is provided on the upper portion of the side wall of the pressure shell, and the second synthesis gas outlet is connected to a second gas collecting pipe.

[0013] Preferably, the second gas collecting pipe includes an annular pipe connected to the second synthesis gas outlet, and a plurality of pipe segments are connected at intervals on the annular pipe, and the pipe segments are arranged vertically downward, wherein the diameter ratio of the annular pipe to the grate is 0.6~0.8:1.

[0014] The present invention has at least the following beneficial effects:

[0015] First, the gasifier enters the main steam port and the auxiliary steam port in two ways respectively. The gasifier from the main steam port increases the flame intensity in the center of the furnace and significantly improves the bed penetration; the gasifier from the auxiliary steam port is sprayed radially toward the center of the furnace to enhance the flame intensity around the furnace; with the cooperation of the central flame and the peripheral flame, the height of the gasification bed can be significantly increased, and the gasification reaction time can be increased, so as to achieve the purpose of increasing the raw material processing capacity and realizing the large-scale device.

[0016] Second, the present invention increases the ventilation volume of the central channel of the grate and the flame height of the grate by changing the number of the central channel air outlet holes and the number of the edge channel air outlet holes in the grate, thereby increasing the height of the gasification bed in the furnace and the processing capacity of raw materials.

[0017] Third, the requirements for raw materials are reduced, and the particle size range can be expanded to 0~100mm. Raw materials such as coal or biomass with poor thermal stability can be gasified, avoiding the raw materials being easily pulverized by heat. There is no possibility of excessive bed pressure difference, which is safer.

[0018] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a graded non-slag fixed bed gasifier according to one of the technical solutions described in the present invention. DETAILED DESCRIPTION

[0020] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0021] like Figure 1 As shown, the present invention provides a hierarchical non-slag fixed bed gasifier, comprising:

[0022] The pressure shell 1 is provided with a material inlet 11 at the top and a slag outlet 12 at the bottom. The pressure shell 1 is provided with a gasifying agent inlet and a first synthesis gas outlet 13 at the upper portion of the side wall of the pressure shell 1;

[0023] The grate 3 is arranged at the lower part of the pressure-bearing shell 1. The air outlet holes within the radial direction of 0.7-0.8D of the grate 3 are central channels, and the remaining air outlet holes are edge channels. The total cross-sectional area of the air outlet holes in the central channel and the total cross-sectional area of the air outlet holes in the edge channels are in a ratio of 2~3:1.

[0024] In this technical solution, the internal space of the pressure-bearing shell 1 is the furnace 4. The shape of the pressure-bearing shell 1 is set according to the existing technology. The center of the grate 3 is the center of the circle. The air outlet holes within the radial range of 0.7-0.8D from the center of the grate 3 are the central channel, and the remaining air outlet holes are edge channels. The larger the proportion of the central channel, the higher the flame height. The total cross-sectional area of the air outlet holes in the central channel and the total cross-sectional area of the air outlet holes in the edge channels are 2-3:1, that is, the ratio of the sum of the cross-sectional areas of all the air outlet holes in the central channel to the sum of the cross-sectional areas of all the air outlet holes in the edge channels is 2-3:1; Working principle of gasifier: carbon-containing block The slag enters the gasifier through the material inlet, and is transformed into ash by a complex redox reaction. It moves downward in sequence through the drying layer, retorting layer, gasification layer, and ash layer (the space in the furnace 4 is divided into drying layer, retorting layer, gasification layer, and ash layer according to the reaction conditions and material changes). The grate 3 rotates and drives the scraper to crush the ash, and then the ash falls to the slag outlet 12 under the action of its own gravity and is discharged from the gasifier; the gasifying agent enters the furnace 4 from the gasifying agent inlet and reacts with the carbon-containing blocks to be transformed into a synthesis gas mainly composed of CO, H2, and CH4, which is entrained with tar and other substances produced by retorting and is sent out of the gasifier through the first synthesis gas outlet 13.

[0025] By adopting this technical solution, the present invention increases the ventilation volume of the central channel of the grate 3 and the flame height of the grate 3 by changing the number of the central channel air outlet holes and the number of the edge channel air outlet holes in the grate 3, thereby increasing the height of the gasification bed in the furnace 4 and the processing capacity of the raw materials.

[0026] In another technical solution, the inner wall of the pressure-bearing shell 1 is provided with a heat-insulating layer 2, and the heat-insulating layer 2 is a membrane-type water-cooled wall structure.

[0027] In another technical solution, the gasifying agent inlet includes a main steam port 14 and an auxiliary steam port 15. The main steam port 14 is provided at the bottom of the pressure shell 1 and is connected to the grate 3. The auxiliary steam port 15 is provided on the side wall of the pressure shell 1. The auxiliary steam port 15 is located on one side of the pressure shell 1 and is connected to a gasifying agent distributor 5. The gasifying agent (such as steam, oxygen, CO2) enters the main steam port 14 and the auxiliary steam port 15 in two ways, respectively. The gasifying agent from the main steam port 14 is distributed by the grate 3 and then enters the furnace 4 from bottom to top, and contacts and reacts with the carbon-containing blocks in the central area of the furnace 4 in reverse. By adopting this technical solution, the gasifying agent enters the main steam port 14 and the auxiliary steam port 15 in two ways respectively. The gasifying agent from the main steam port 14 increases the flame intensity at the center of the furnace 4 and significantly improves the bed penetration; the gasifying agent from the auxiliary steam port 15 is sprayed radially toward the center of the furnace 4, thereby enhancing the flame intensity around the furnace 4; with the cooperation of the central flame and the peripheral flame, the height of the gasification bed can be significantly increased, and the gasification reaction time can be increased, so as to achieve the purpose of increasing the raw material processing capacity and realizing the large-scale device.

[0028] In another technical solution, the ratio of the distance between the gasifying agent distributor 5 and the top of the grate 3 to the diameter of the grate 3 is 0.5-1.5:1. Taking a grate 3 with a diameter of 3.2m as an example, the height of the gasifying agent distributor 5 from the grate 3 is 1.6-4.8m. This technical solution can effectively increase the height of the gasification layer.

[0029] In another technical solution, the air intake of the auxiliary steam port 15 accounts for 10-30% of the total air volume. When the coal type changes or load adjustment occurs, the air volume can be adjusted in time by adjusting the valve. This technical solution improves gasification performance.

[0030] In another technical solution, a second syngas outlet 17 is provided on the upper sidewall of the pressure shell 1. This outlet 17 is located within the pressure shell 1 and is connected to a second gas header. This technical solution allows the present invention to discharge high-temperature syngas from the gasifier for heat recovery by providing this second syngas outlet 17. This second syngas outlet 17 can also be used to control the temperature of the retorting layer (and thus the amount of syngas discharged from the second syngas outlet 17) to maximize tar byproduct production.

[0031] In another technical solution, the second gas header comprises an annular tube connected to the second syngas outlet 17. The annular tube is interspersed with multiple tube segments at intervals, extending vertically downward. The diameter ratio of the annular tube to the grate 3 is 0.6-0.8:1. The annular tube and grate 3 are coaxially arranged, with the lower ends of the tube segments open. This technical solution, through the annular tube and tube segments, allows the central and peripheral flame edges to be concentrated, balancing the temperature above the gasification bed and facilitating downward movement of feedstock at the flame edges.

[0032] The number of equipment and processing scale described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the staged non-slag fixed bed gasifier of the present invention will be apparent to those skilled in the art.

[0033] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A graded non-slag fixed bed gasifier, characterized in that: include: A pressure shell is provided with a material inlet at the top and a slag outlet at the bottom, a gasifying agent inlet at the pressure shell, and a first synthesis gas outlet at the upper portion of the side wall of the pressure shell; The grate is arranged at the lower part of the pressure-bearing shell. The air outlet holes within the radial direction of 0.7-0.8D of the grate are central channels, and the remaining air outlet holes are edge channels. The ratio of the total cross-sectional area of the air outlet holes in the central channel to the total cross-sectional area of the air outlet holes in the edge channels is 2~3:

1.

2. The hierarchical non-slag fixed bed gasifier according to claim 1, characterized in that: The inner wall of the pressure-bearing shell is provided with a heat insulation layer, and the heat insulation layer is a membrane-type water-cooled wall structure or a water jacket structure.

3. The hierarchical non-slag fixed bed gasifier according to claim 1, characterized in that: The gasifying agent inlet includes a main steam port and an auxiliary steam port. The main steam port is arranged at the bottom of the pressure shell and is connected to the grate. The auxiliary steam port is arranged on the side wall of the pressure shell. The auxiliary steam port is located on one side inside the pressure shell and is connected to a gasifying agent distributor.

4. The hierarchical non-slag fixed-bed gasifier according to claim 3, characterized in that: The ratio of the distance between the gasifying agent distributor and the top of the grate to the diameter of the grate is 0.5-1.5:

1.

5. The hierarchical non-slag fixed-bed gasifier according to claim 3, characterized in that: The air intake of the auxiliary steam port accounts for 10-30% of the total air volume.

6. The hierarchical non-slag fixed-bed gasifier according to claim 1, characterized in that: A second synthesis gas outlet is provided on the upper portion of the side wall of the pressure-bearing shell, and the second synthesis gas outlet is connected to a second gas collecting pipe.

7. The hierarchical non-slag fixed-bed gasifier according to claim 6, characterized in that: The second gas collecting pipe includes an annular pipe connected to the second synthesis gas outlet, and a plurality of pipe segments are connected to the annular pipe at intervals. The pipe segments are arranged vertically downward, wherein the diameter ratio of the annular pipe to the grate is 0.6-0.8:1.

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