Staged heterogeneous fixed-bed gasifier

Abstract

This invention discloses a staged non-homogeneous fixed-bed gasifier, comprising: a pressure-bearing shell with a material inlet at the top and a slag outlet at the bottom, a gasifying agent inlet, and a first syngas outlet on the upper part of the side wall of the pressure-bearing shell; and a grate located at the lower part of the pressure-bearing shell, wherein the air outlet channel within a radial radius of 0.7-0.8D of the grate is a central channel, and the remaining air outlet channels are edge channels, with a ratio of the central channel to the edge channels of 2-3:1. This invention increases the airflow through the central channel of the grate and the flame height of the grate by changing the ratio of the central channel to the edge channels, thereby increasing the height of the gasification bed and the processing capacity of the raw materials within the furnace.

Description

Technical Field

[0001] This invention relates to the field of carbonaceous material gasification technology. More specifically, this invention relates to a staged heterogeneous fixed-bed gasifier. Background Technology

[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 gas flow field in the coal bed, so that the gasification reaction in the feedstock can proceed fully. During operation, the grate of a traditional pressurized fixed-bed gasifier generally produces gas uniformly, and the height of each bed layer in the furnace is basically constant along the axis. With a fixed gasifier diameter, this limits the feedstock throughput and is not suitable for large-scale production. Summary of the Invention

[0003] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0004] Another objective of this invention is to provide a staged non-uniform fixed-bed gasifier, which increases the airflow through 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 and the amount of raw materials processed in the furnace.

[0005] To achieve these objectives and other advantages of the present invention, a staged heterogeneous fixed-bed gasifier is provided, comprising:

[0006] The pressure-bearing shell has a material inlet at the top and a slag outlet at the bottom. The pressure-bearing shell has a main gasifying agent inlet and an auxiliary gasifying agent inlet. The main gasifying agent inlet is located at the bottom of the pressure-bearing shell, and the auxiliary gasifying agent inlet is located on the side wall of the pressure-bearing shell. A first syngas outlet is located at the upper part of the side wall of the pressure-bearing shell.

[0007] A grate is located at the lower part of the pressure-bearing shell. The air outlet channel within a radial distance of 0.7-0.8D of the grate is the central channel, and the remaining air outlet channels are the edge channels. The air volume ratio of the central channel to the edge channels is 2-3:1. The main gasifying agent inlet is connected to the grate.

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

[0009] Preferably, the auxiliary gasifying agent inlet is located on one side inside the pressure-bearing shell and is connected to a gasifying agent distributor.

[0010] Preferably, the grate is provided with horizontal baffles, the central channel is located above the baffles, and the edge channels are located below the baffles;

[0011] The main gasifying agent inlet includes a first steam port and a second steam port. The first steam port is connected to a first steam inlet pipe. The end of the first steam inlet pipe extends vertically into the grate and is located below the partition plate. The pressure-bearing shell is provided with a second steam port. The second steam port is connected to a second steam inlet pipe. The diameter of the second steam inlet pipe is smaller than the diameter of the first steam inlet pipe. The end of the second steam inlet pipe extends vertically through the first steam inlet pipe and the partition plate extends above the partition plate. The vertical sides of the first steam inlet pipe and the second steam inlet pipe are both coaxially arranged with the grate.

[0012] Preferably, the distance between the gasifying agent distributor and the top of the grate is in the ratio of 0.5 to 1.5:1 to the diameter of the grate.

[0013] Preferably, the intake volume of the auxiliary gasifier is 10-30% of the total gas volume.

[0014] Preferably, the pressure-bearing housing has multiple temperature sensors spaced apart on its upper and lower sides.

[0015] Preferably, the upper part of the side wall of the pressure-bearing shell is provided with a second syngas outlet, and the second syngas outlet is connected to a second gas collecting pipe.

[0016] Preferably, the second gas collecting pipe includes a ring pipe communicating with the second syngas outlet, and multiple pipe sections are connected at intervals on the ring pipe. The pipe sections are arranged vertically downward, wherein the diameter ratio of the ring pipe to the grate is 0.6 to 0.8:1.

[0017] The present invention has at least the following beneficial effects:

[0018] First, the gasifying agent is divided into two streams and enters the main gasifying agent inlet and the auxiliary gasifying agent inlet respectively. The gasifying agent from the main gasifying agent inlet increases the flame intensity in the center of the furnace and significantly improves the bed penetration. The gasifying agent from the auxiliary gasifying agent inlet is injected radially towards the center of the furnace, enhancing 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, thereby increasing the feedstock throughput and realizing the large-scale operation of the equipment.

[0019] Secondly, by changing the ratio of the central channel to the edge channel in the grate, the present invention increases the air flow of the central channel of the grate and the flame height of the grate, thereby increasing the height of the gasification bed and the amount of raw materials processed in the furnace.

[0020] Third, it reduces the requirements for raw materials, and the particle size range can be expanded to 0-100mm. It can gasify raw materials such as coal or biomass with poor thermal stability, avoids the raw materials from being easily pulverized by heat, and eliminates the possibility of excessive pressure difference in the bed, making it safer.

[0021] Fourth, by setting up a baffle, a first steam inlet, a first steam inlet pipe, a second steam inlet, and a second steam inlet, this invention can not only provide gasifying agent separately to the central channel and the edge channel, but also adjust the air volume ratio between the central channel and the edge channel by adjusting the air volume in the first steam inlet pipe and the second steam inlet pipe.

[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the staged heterogeneous fixed-bed gasifier according to one of the technical solutions of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the grate according to one of the technical solutions of the present invention. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0026] like Figure 1 and 2 As shown, the present invention provides a staged heterogeneous fixed-bed gasifier, comprising:

[0027] The pressure-bearing shell 1 has a material inlet 11 at the top and a slag outlet 12 at the bottom. The pressure-bearing shell 1 has a main gasifying agent inlet and an auxiliary gasifying agent inlet 15. The main gasifying agent inlet is located at the bottom of the pressure-bearing shell 1, and the auxiliary gasifying agent inlet 15 is located on the side wall of the pressure-bearing shell 1. A first syngas outlet 13 is located at the upper part of the side wall of the pressure-bearing shell 1.

[0028] The grate 3 is located at the lower part of the pressure-bearing shell 1. The air outlet channel within a radial direction of 0.7-0.8D of the grate 3 is the central channel, and the remaining air outlet channels are the edge channels. The air volume ratio of the central channel to the edge channel is 2-3:1. The main gasifying agent inlet is connected to the grate.

[0029] 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 adopts the existing technology setting, with the center of the grate 3 as the center, and the air outlet channel within a radial range of 0.7-0.8D from the center as the central channel, and the remaining air outlet channels as edge channels. The larger the proportion of the central channel, the higher the flame height. The working principle of the gasifier: Carbon-containing blocky materials enter the gasifier through the material inlet, and are transformed into ash and slag through complex oxidation-reduction reactions. They then pass through the drying layer, the dry distillation layer, the gasification layer, and the ash layer in sequence (the internal space of the furnace 4 is divided into the drying layer, the dry distillation layer, the gasification layer, and the ash layer according to the reaction situation and material changes). The ash layer moves downwards, and the rotating grate 3 drives the scraper to break up the ash and slag. Under the gravity of the ash and slag, it falls to the slag outlet 12 and is discharged from the gasifier. The gasifying agent (such as steam, oxygen, CO2) enters the main gasifying agent inlet and the auxiliary gasifying agent inlet 15 in two separate paths. The gasifying agent from the main gasifying agent inlet is distributed by the grate 3 and enters the furnace 4 from bottom to top. It comes into counter-current contact with the carbon-containing blocky material in the central area of ​​the furnace 4 and reacts. The gasifying agent enters the furnace 4 and reacts with the carbon-containing blocky material to transform into syngas mainly composed of CO, H2, and CH4. The tar and other substances from the dry distillation are sent out of the gasifier through the first syngas outlet 13.

[0030] By adopting this technical solution, the present invention increases the airflow in the central channel of grate 3 and the flame height of grate 3 by changing the airflow ratio between the central channel and the edge channel of grate 3, thereby increasing the height of the gasification bed and the raw material throughput in furnace 4. The gasifying agent is divided into two streams and enters the main gasifying agent inlet and the auxiliary gasifying agent inlet 15 respectively. The gasifying agent in the main gasifying agent inlet increases the flame intensity in the center of furnace 4 and significantly improves the bed penetration. The gasifying agent in the auxiliary gasifying agent inlet 15 is injected radially towards the center of furnace 4, 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, thereby increasing the raw material throughput and realizing the large-scale operation of the device.

[0031] In another technical solution, the inner wall of the pressure-bearing outer shell 1 is provided with a heat insulation layer 2, which is a membrane water-cooled wall structure.

[0032] In another technical solution, the auxiliary gasifying agent inlet 15 is located on one side inside the pressure-bearing outer shell 1 and is connected to the gasifying agent distributor 5. This technical solution facilitates the entry of the gasifying agent into the furnace 4 through the auxiliary gasifying agent inlet 15.

[0033] In another technical solution, the grate 3 is provided with a horizontal partition 20, the central channel is located above the partition 20, and the edge channel is located below the partition 20;

[0034] The main gasifying agent inlet includes a first steam port 14 and a second steam port 21. The first steam port 14 is connected to a first steam inlet pipe, the end of which extends vertically into the grate 3 and is located below the partition plate 20. The second steam port 21 is connected to a second steam inlet pipe, the diameter of which is smaller than that of the first steam inlet pipe. The end of the second steam inlet pipe extends vertically through the first steam inlet pipe and the partition plate 20 and extends above the partition plate 20. The vertical sides of both the first and second steam inlet pipes are coaxially arranged with the grate 3. The tops of both the first and second steam inlet pipes are open. The partition plate 20 has a through hole in its center, the diameter of which is slightly larger than that of the second steam inlet pipe so that the partition plate can rotate relative to the second steam inlet pipe (the air volume ratio of the central channel to the edge channel can be adjusted to 2-3:1 by adjusting the air volume of the first and second steam ports). By adopting this technical solution, the present invention, through the setting of a baffle, a first steam inlet 14, a first steam inlet pipe, a second steam inlet 21, and a second steam inlet, can not only provide gasifying agent separately to the central channel and the edge channel, but also adjust the air volume ratio of the central channel and the edge channel by adjusting the air volume in the first steam inlet pipe and the second steam inlet pipe.

[0035] In another technical solution, the distance between the gasifying agent distributor 5 and the top of the grate 3 is in the ratio of 0.5 to 1.5:1 to the diameter of the grate 3. 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 to 4.8m. This technical solution can effectively increase the height of the gasification layer.

[0036] In another technical solution, the intake air volume of the auxiliary gasifying agent inlet 15 accounts for 10-30% of the total gas volume. When the coal type changes or load adjustments occur, the gas volume can be adjusted in a timely manner through the regulating valve. This technical solution improves gasification performance.

[0037] In another technical solution, multiple temperature sensors 16 are spaced apart on the upper and lower sides of the pressure-bearing shell sidewall. This solution is used to detect the actual temperature at different heights within the gasifier, and based on the actual temperature, optimal process conditions are controlled (temperature is controlled by adjusting the amount of steam added to the gasifying agent and controlling the grate speed), thereby reducing consumption.

[0038] In another technical solution, a second syngas outlet 17 is provided on the upper part of the side wall of the pressure-bearing shell. The second syngas outlet 17 is located inside the pressure-bearing shell 1 and is connected to a second gas collecting pipe. Using this technical solution, the present invention discharges high-temperature syngas from the gasifier through the second syngas outlet 17 for heat recovery; it can also be used to control the temperature of the pyrolysis layer (controlling the amount of syngas discharged from the outlet of the second syngas 17) to achieve maximum tar by-product yield.

[0039] In another technical solution, the second gas collecting pipe includes a ring pipe connected to the second syngas outlet 17. Multiple pipe sections are spaced apart on the ring pipe, and the pipe sections are vertically downwards. The diameter ratio of the ring pipe to the grate 3 is 0.6–0.8:1. The ring pipe and grate 3 are coaxially aligned, and the lower ends of the pipe sections are open. Using this technical solution, the present invention, by setting up the ring pipe and pipe sections, concentrates the central flame edge and the peripheral flame edge, equalizes the temperature in the upper part of the gasification bed, and facilitates the downward movement of raw materials at the flame edge.

[0040] The number of devices and processing capacity described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the staged heterogeneous fixed-bed gasifier of this invention will be readily apparent to those skilled in the art.

[0041] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A staged non-homogeneous fixed-bed gasifier, characterized in that, include: The pressure-bearing shell has a material inlet at the top and a slag outlet at the bottom. The pressure-bearing shell has a main gasifying agent inlet and an auxiliary gasifying agent inlet. The main gasifying agent inlet is located at the bottom of the pressure-bearing shell, and the auxiliary gasifying agent inlet is located on the side wall of the pressure-bearing shell. A first syngas outlet is located at the upper part of the side wall of the pressure-bearing shell. A grate is located at the lower part of the pressure-bearing shell. Centered on the center of the grate, a central channel extends radially from the center to an air outlet within a radius of 0.7 to 0.8 mm, while the remaining air outlet channels are edge channels. A horizontal baffle is provided inside the grate. The central channel is located above the baffle, and the edge channels are located below the baffle. The main gasifying agent inlet includes a first steam port and a second steam port. The first steam port is connected to a first steam inlet pipe, the end of which extends vertically into the grate and is located below the baffle. The second steam port is connected to a second steam inlet pipe, the diameter of which is smaller than that of the first steam inlet pipe. The end of the second steam inlet pipe vertically passes through the first steam inlet pipe and the baffle, extending above the baffle. The vertical sides of both the first and second steam inlet pipes are coaxially aligned with the grate. The first and second steam inlet pipes are both open at the top. The partition has a through hole in the center. The diameter of the through hole is larger than the diameter of the second steam inlet pipe so that the partition can rotate relative to the second steam inlet pipe. By adjusting the air volume in the first and second steam inlet pipes, the air volume ratio of the central channel to the edge channel can be adjusted to 2 to 3:

1. The inner wall of the pressure-bearing outer shell is provided with a heat insulation layer, which is a membrane water-cooled wall structure. The auxiliary gasifying agent inlet is located on one side inside the pressure-bearing shell and is connected to a gasifying agent distributor. The distance between the gasifying agent distributor and the top of the grate is 0.5 to 1.5 times the diameter of the grate. A second syngas outlet is provided on the upper part of the side wall of the pressure-bearing shell. The second syngas outlet is connected to a second gas collecting pipe. The second gas collecting pipe includes a ring pipe connected to the second syngas outlet. Multiple pipe sections are connected at intervals on the ring pipe. The pipe sections are arranged vertically downward. The diameter ratio of the ring pipe to the grate is 0.6 to 0.8 times the diameter of the grate. The ring pipe is coaxial with the grate. The lower end of the pipe section is open.

2. The staged heterogeneous fixed-bed gasifier as described in claim 1, characterized in that, Multiple temperature sensors are spaced apart on the upper and lower sides of the pressure-bearing outer shell.

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