A flue gas recirculation gasification burner

Abstract

This invention discloses a flue gas recirculation gasification burner, comprising a central tube, a first annular channel outside the central tube, a second annular channel outside the first annular channel, a third annular channel outside the second annular channel, and a fourth annular channel outside the third annular channel. A cylindrical jacket is fixedly installed inside the third annular channel. An annular distribution seat is fixedly connected to the upper end of the fourth annular channel. Several nozzles evenly distributed in a ring array are fixedly installed on the upper side of the distribution seat. The tail of the nozzles is connected to the fourth annular channel through a conduit located in the distribution seat. The central tube and the fourth annular channel are used to introduce oxygen. The high-speed injection of oxygen from the outer side through the nozzles creates a recirculation zone near the burner nozzle, entraining the recirculated flue gas to form a flue gas recirculation, achieving staged mixing and combustion, thereby reducing the temperature at the burner nozzle and extending its lifespan. Simultaneously, it extends the residence time of the syngas, effectively improving the gasification reaction efficiency.

Description

Technical Field

[0001] This invention relates to the field of gasification technology, specifically to a gasification burner capable of internal flue gas recirculation. Background Technology

[0002] Gasification refers to the process by which organic matter undergoes a series of chemical reactions with a gasifying agent (such as steam, air, or oxygen) within a specific device (gasifier) ​​at certain temperature and pressure, converting the organic matter into syngas (mainly containing combustible gases such as CO and H2). Syngas is primarily used in the synthesis of ammonia, methanol, and natural gas, as well as in refinery hydrogen production, blast furnace reduction in ironmaking, chemical and metallurgical industries, combined cycle power generation units, and industrial and residential gas applications. In recent years, the gasification industry has gradually diversified its raw material sources. Gasification using coal as the main raw material (pulverized coal and coal-water slurry) has become more technologically stable, while emerging industries such as residue oil hydrogen production and heavy oil cracking have added vitality to the gasification industry. The gasification burner is a key piece of equipment in a gasification unit, and its lifespan directly affects the stable long-term operation of the gasification system.

[0003] Currently used gasification burners concentrate the mixing of oxygen and fuel at the burner nozzle, concentrating the entire reaction zone at the burner outlet. This results in extremely high radiant temperatures near the outlet. Despite cooling devices, these devices often crack or even perforate the burner within a short period, causing premature burner shutdown and impacting the operation of the entire gasification unit. For example, patent CN213060755U discloses a burner for residual oil gasification that uses stratified oxygen delivery with steam added in between to form a five-channel burner. Although oxygen is delivered in stages, the mixing of all oxygen and fuel is still concentrated at the nozzle, making it prone to multi-layer nozzle deformation, cooling structure leaks, and short lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide a flue gas recirculation burner to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a flue gas recirculation gasification burner, comprising a central tube, a first annular channel on the outer side of the central tube, a second annular channel on the outer side of the first annular channel, a third annular channel on the outer side of the second annular channel, and a fourth annular channel on the outer side of the third annular channel. The upper ends of the central tube, the first annular channel, the second annular channel, and the third annular channel are all tapered structures with reduced diameters and together form the central burner orifice. A cylindrical jacket is fixedly installed inside the third annular channel, which guides cooling water to the central burner orifice for cooling. An annular distribution seat is fixedly connected to the upper end of the fourth annular channel. A plurality of nozzles evenly distributed in a ring array are fixedly installed on the upper side of the distribution seat. The tail of the nozzles is connected to the fourth annular channel through a conduit located in the distribution seat. The central tube and the fourth annular channel are used to introduce oxygen.

[0006] Preferably, the upper end of the first circulation channel is provided with a first cone portion, the inner cavity slope of the first cone portion is angle A, and the upper end of the second circulation channel is provided with a second cone portion, the inner cavity slope of the second cone portion is angle B, wherein angle A is smaller than angle B.

[0007] Preferably, the size of angle A is 7.5° to 15°, and the size of angle B is 15° to 45°.

[0008] Preferably, the nozzle is tilted towards the center at an angle C, and the angle C is between 7.5° and 15°.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: The structure of the present invention mainly divides oxygen into central oxygen and outer oxygen, and sets fuel, reducing gas and cooling structure from the inside to the outside between the two. The outer oxygen is injected at high speed through the nozzle to form a recirculation zone near the burner nozzle, and the recirculated flue gas is induced to form an internal flue gas circulation, realizing staged mixing and combustion, thereby reducing the temperature at the central burner nozzle to extend its life, and at the same time extending the residence time of the syngas, effectively improving the gasification reaction efficiency. Attached Figure Description

[0010] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0011] Figure 2 This is a partial cross-sectional view of the central burner opening of the present invention;

[0012] Figure 3 This is a top view of the structure of the present invention.

[0013] In the diagram: 1. Central tube; 2. First circulation channel; 3. Second circulation channel; 4. Third circulation channel; 5. Fourth circulation channel; 6. Distribution seat; 7. Conduit; 8. Nozzle; 9. First cone; 10. Second cone; 11. Jacket. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0015] Please see Figure 1-3 This invention provides a technical solution: a flue gas internal circulation gasification burner, comprising a central tube 1, a first annular channel 2 on the outer side of the central tube 1, a second annular channel 3 on the outer side of the first annular channel 2, a third annular channel 4 on the outer side of the second annular channel 3, and a fourth annular channel 5 on the outer side of the third annular channel 4. The upper ends of the central tube 1, the first annular channel 2, the second annular channel 3, and the third annular channel 4 are all tapered structures with reduced diameters and together form the central burner inlet. The central tube 1 and the fourth annular channel 5 are used to introduce oxygen, the first annular channel 2 is used to introduce fuel (which can be pulverized coal + CO2, residual oil, heavy oil, or coal-water slurry), and the second annular channel 3 is used to introduce gas, which can be approximately 15-20% oxygen or a non-oxidizing gas (fuel gas, syngas CO + H2, steam, CO2, etc.).

[0016] A cylindrical jacket 11 is fixedly installed inside the third annular channel 4. The jacket 11 guides the cooling water to the central burner orifice for cooling. An annular distribution seat 6 is fixedly connected to the upper end of the fourth annular channel 5. Several nozzles 8 are evenly distributed in a ring array on the upper side of the distribution seat 6. The nozzles 8 are tilted towards the center at an angle C, which is 7.5° to 15°. The tail of the nozzles 8 is connected to the fourth annular channel 5 through a conduit 7 located in the distribution seat 6. The distribution seat 6 is made of high-temperature resistant material. The nozzles 8 spray oxygen away from the central burner orifice for mixing and combustion, thereby protecting the central burner orifice from overheating and burning.

[0017] The upper end of the first annular channel 2 is provided with a first cone 9, the inclination of which is angle A. The upper end of the second annular channel 3 is provided with a second cone 10, the inclination of which is angle B. Angle A is smaller than angle B, the size of angle A is 7.5° to 15°, and the size of angle B is 15° to 45°. The oxygen discharged from the central tube 1 and the gas output from the second cone 10 are located on the inner and outer sides of the fuel injection, respectively, which can ensure that the fuel is fully atomized.

[0018] Working principle: Central oxygen is introduced through the central tube 1, and external oxygen is introduced through the fourth annular channel 5, with the external oxygen accounting for more than 70% of the total oxygen consumption. The first annular channel 2 is used to introduce fuel, and the second annular channel 3 passes through a small amount of oxygen or reducing gas flow. The fuel is atomized at the annular central burner orifice and undergoes an incomplete reaction at a low temperature, effectively protecting the central burner orifice. The oxygen injected by the nozzle 8 mixes and combusts with the incompletely combusted gas mixture at a location away from the central burner orifice, thus achieving staged control. A certain negative pressure recirculation zone is formed near the central burner orifice, recirculating and mixing the fuel and part of the flue gas, improving the mixing effect with the fuel, and extending the residence time of the syngas, effectively improving the gasification reaction efficiency.

[0019] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flue gas recirculation gasification burner, comprising a central pipe (1), the outer side of the central pipe (1) being provided with a first annular flow channel (2), the outer side of the first annular flow channel (2) being provided with a second annular flow channel (3), the outer side of the second annular flow channel (3) being provided with a third annular flow channel (4), the outer side of the third annular flow channel (4) being provided with a fourth annular flow channel (5), characterized in that: The upper ends of the central pipe (1), the first annular flow channel (2), the second annular flow channel (3) and the third annular flow channel (4) are all tapered structures with reduced diameters and jointly form a central burner port, the third annular flow channel (4) is fixedly provided with a cylindrical jacket (11) inside, the jacket (11) guides cooling water to the central burner port for cooling, the upper end of the fourth annular flow channel (5) is fixedly connected with an annular distribution seat (6), the upper side of the distribution seat (6) is fixedly provided with a plurality of nozzles (8) uniformly distributed in an annular array, the nozzles (8) are inclined towards the center at an angle C, the angle C is 7.5°-15°, the tail of the nozzle (8) is connected to the fourth annular flow channel (5) through a conduit (7) in the distribution seat (6), the central pipe (1) and the fourth annular flow channel (5) are used for feeding oxygen, and the consumption of oxygen in the fourth annular flow channel (5) is not less than 70% of the total consumption.

2. A flue gas recirculation capable gasification burner according to claim 1, characterized in that: The upper end of the first annular flow channel (2) is provided with a first taper (9), the inner cavity of the first taper (9) has an inclination angle A, the upper end of the second annular flow channel (3) is provided with a second taper (10), the inner cavity of the second taper (10) has an inclination angle B, and the angle A is smaller than the angle B.

3. A flue gas recirculation gasification burner according to claim 2, characterized in that: The angle A is 7.5°-15°, and the angle B is 15°-45°.

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