Combustor device capable of realizing mixing of natural gas and ammonia gas

Abstract

A natural gas ammonia-doped optimized combustion device comprises an inner center pipe, a primary air pipe assembly, a natural gas pipe assembly, an ammonia gas pipe assembly, a secondary air pipe assembly and a recirculation pipe assembly, the primary air pipe assembly, the natural gas pipe assembly, the ammonia gas pipe assembly, the secondary air pipe assembly and the recirculation pipe assembly are sequentially arranged outside the inner center pipe, the design of the ammonia center pipe is adopted, ammonia fuel is divided into two parts to be introduced into a combustion chamber, staged combustion of the ammonia fuel is formed, and the combustion efficiency is improved; the flexible and adjustable large-proportion ammonia doping working condition is realized. Fuel is divided into direct-flow air and rotational-flow air to be fed into the combustion chamber, the rotational-flow air enters the combustion device through a tangential channel, is tightly attached to the wall face, forms rotational flow under the action of inertia and centrifugal force and enters the combustion chamber, and therefore rotational-flow air with certain strength is obtained, and the rotational-flow strength is flexible and adjustable by changing the air inflow of the two channels. The multi-stage combustion of fuel can be realized, the stability of ammonia-doped combustion is improved, and the emission of NOx can be greatly reduced while the emission of CO2 is reduced.

Description

Technical Field

[0001] The present invention relates to a technology in the field of thermal power generation, specifically a burner device capable of realizing the blending of natural gas and ammonia. Background Art

[0002] Most existing natural gas - ammonia blending combustion devices use swirling guide vanes to achieve the swirling effect of gas. The swirling intensity of the introduced gas is determined by the vane design and cannot be flexibly adjusted. The channels for each fuel component are fixed, making it difficult to meet the needs of various actual complex industrial conditions, with a relatively complex structure and high control costs. Summary of the Invention

[0003] Aiming at the defects of the prior art that the gas swirling intensity cannot be adjusted and the positions of each fuel channel are fixed, and flexible staged combustion of fuels cannot be achieved, the present invention proposes an optimized natural gas - ammonia combustion device. By adopting the design of an ammonia central tube, the ammonia fuel is divided into two parts and introduced into the combustion chamber to form staged combustion of ammonia fuel, improving the combustion efficiency and enabling flexible adjustment of large - proportion ammonia - blending working conditions. Each fuel is sent into the combustion chamber as direct - current air and swirling air. The swirling air enters the combustion device through the tangential channel, clings to the wall surface, and forms a swirl under the action of inertia and centrifugal force to enter the combustion chamber, thus obtaining a swirling air with a certain intensity. By changing the intake air volume of the two channels, the swirling intensity can be flexibly adjusted. While enabling staged combustion of fuels, it can improve the stability of ammonia - blending combustion, reduce CO 2 emissions and can significantly reduce NO x emissions.

[0004] The present invention is realized through the following technical solutions:

[0005] The present invention relates to a burner device capable of realizing high - efficiency and clean blending of natural gas and ammonia, including: an inner central tube and a primary air duct assembly, a natural gas duct assembly, an ammonia duct assembly, a secondary air duct assembly, and a recirculation duct assembly sequentially arranged outside it. Among them: ammonia fuel is introduced into the inner central tube, and the outlet of the inner central tube is arranged at the center of the combustion device housing; natural gas is introduced into the natural gas duct assembly. The natural gas first undergoes a combustion reaction with the primary air to form a local oxygen - deficient region. The ammonia fuel is sent into the combustion region in a swirling form to strengthen its entrainment and mixing with the high - temperature flue gas, increase the contact time between the ammonia fuel and the high - temperature flue gas, and promote the thermal decomposition of ammonia to achieve high - efficiency and clean combustion.

[0006] The inner central tube, the direct - current secondary air sleeve, and the inlet section of the high - temperature recirculation flue gas sleeve are provided with branch pipes, and the cross - section of the branch pipes is circular.

[0007] The primary air duct assembly, the natural gas duct assembly, and the ammonia duct assembly are respectively provided with direct - current air inlet pipes, and the inlet directions of the three direct - current air inlet pipes are at the same angle as the outlet direction of the combustion device.

[0008] The primary air duct assembly, natural gas duct assembly, and ammonia duct assembly are respectively provided with tangential swirl air inlet pipes. The three tangential swirl air inlet pipes can adjust the ratio of direct current air to swirl air to achieve adjustable swirl intensity. Technical effects

[0009] Through the structural design of steplessly adjustable fuel swirl intensity in the present invention, the swirl intensity of the introduced gas is quantitatively evaluated by the swirl number. Compared with the prior art, the present invention can improve the flexibility of the fuel ratio of the burner, achieve large-scale flexible ammonia blending combustion, improve the combustion stability, and reduce CO 2 emissions while reducing NO x emissions, and achieve stable combustion of natural gas blended with ammonia with high efficiency and cleanliness. Description of the drawings

[0010] Figure 1 It is a cross-sectional view of the present invention;

[0011] Figure 2 It is a front view of the present invention;

[0012] Figure 3 It is a schematic diagram of the overall structure and working principle of the present invention;

[0013] Figure 4 It is a schematic diagram of the tapered pipe of the present invention.

[0014] In the figure: 1 inner central pipe, 2 inner central intake branch pipe, 3 primary air duct, 4 direct current primary air inlet pipe, 5 tangential swirl primary air inlet pipe, 6 natural gas pipe, 7 direct current natural gas inlet pipe, 8 tangential swirl natural gas inlet pipe, 9 ammonia pipe, 10 direct current ammonia inlet pipe, 11 tangential swirl ammonia inlet pipe, 12 direct current secondary air sleeve, 13 direct current secondary air inlet pipe, 14 high-temperature recirculation flue gas sleeve, 15 high-temperature recirculation flue gas inlet pipe. Specific embodiments

[0015] As Figure 1 shown, this embodiment relates to an optimized combustion device for natural gas blended with ammonia, including: an inner central pipe 1 and a primary air duct assembly, natural gas duct assembly, ammonia duct assembly, secondary air duct assembly, and recirculation pipe assembly sequentially arranged outside it. Among them: the outlet of the inner central pipe 1 is arranged at the center of the combustion device housing. Ammonia fuel is introduced into the inner central pipe to form fuel staged combustion, improve the combustion efficiency, and increase the ammonia blending ratio; the secondary air channel is located outside the central fuel area to achieve air staged combustion, form a lean-burn - rich-burn two-stage combustion area, improve the combustion performance, and reduce NO xEmissions. At the same time, the high-momentum DC secondary wind energy can effectively prevent the flame from flaring and avoid slagging on the wall surface near the burner. The high-temperature flue gas comes from the flue gas at the tail of the furnace, acting as a heat dilution body to avoid local high temperatures, evenly distribute the temperature, and reduce thermal NO x generation.

[0016] The primary air duct assembly described above includes: a primary air duct 3 disposed outside the inner central tube 1, a DC primary air inlet pipe 4 and a tangential swirl primary air inlet pipe 5 disposed on the primary air duct 3.

[0017] The latter half of the primary air duct 3 is provided with a tapered structure.

[0018] The tangential swirl primary air inlet pipe 5 is disposed tangentially to the main fuel passage.

[0019] The natural gas duct assembly described above includes: a natural gas duct 6 disposed outside the primary air duct assembly, a DC natural gas inlet pipe 7 and a tangential swirl natural gas inlet pipe 8 disposed on the natural gas duct 6.

[0020] The latter half of the natural gas duct 6 is provided with a tapered structure.

[0021] The tangential swirl natural gas inlet pipe 8 is disposed tangentially to the main fuel passage.

[0022] The ammonia duct assembly described above includes: an ammonia duct 9 disposed outside the natural gas duct assembly, a DC ammonia inlet pipe 10 and a tangential swirl ammonia inlet pipe 11 disposed on the ammonia duct 9.

[0023] The latter half of the ammonia duct 9 is provided with a tapered structure.

[0024] The tangential swirl ammonia inlet pipe 11 is disposed tangentially to the main fuel passage.

[0025] The three annular spaces formed by the inner central tube 1 and the primary air duct 3, the primary air duct 3 and the natural gas duct 6, and the natural gas duct and the ammonia duct 9 are respectively the primary air passage, the natural gas passage, and the ammonia passage.

[0026] The primary air duct 3, the natural gas duct 6, and the ammonia duct 9 all include: an inlet section, a tapered section, and a straight pipe section. The DC primary air inlet pipe 4, the DC natural gas inlet pipe 7, and the DC ammonia inlet pipe 10 are respectively disposed in the corresponding inlet sections; the swirl primary air inlet pipe 5, the swirl natural gas inlet pipe 8, and the swirl ammonia inlet pipe 11 are respectively disposed at the front of the corresponding tapered sections.

[0027] The DC inlet pipes of each fuel component, namely the DC primary air inlet pipe 4, the DC natural gas inlet pipe 7, and the DC ammonia inlet pipe 10, are at the same angle with the horizontal direction, facilitating the air intake setting in actual combustion work.

[0028] Each component fuel enters from the tangential swirl air inlet pipe, and an initial swirl is generated by the tangential inlet. The reduced section after the tangential swirl air inlet section makes the air flow at a high speed along the wall of the gradually reduced section, further strengthening the swirl intensity, enabling the component fuels to be highly mixed, increasing the contact time of different component fuels, strengthening the combustion process, and promoting efficient and stable combustion of the fuel. The swirl intensity of each component fuel can be flexibly adjusted by changing the direct current air intake and the swirl air intake.

[0029] The described secondary air duct assembly includes: a direct current secondary air sleeve 12 arranged outside the ammonia duct assembly, which is used to achieve staged fuel combustion, form lean-burn - rich-burn secondary combustion, reduce ammonia escape, and achieve efficient and stable combustion. The high-momentum direct current air can also prevent flame flashover and avoid slagging near the burner to the greatest extent.

[0030] A direct current secondary air inlet pipe 13 is provided on the direct current secondary air sleeve 12.

[0031] The described recirculation pipe assembly includes: a high-temperature recirculating flue gas sleeve 14 arranged outside the secondary air duct assembly. The high-temperature recirculating flue gas comes from the high-temperature circulating flue gas at the outlet of the combustion chamber, and it acts as a heat dilution body to avoid local high temperature, make the temperature distribution uniform, and reduce the generation of thermal NO x generation.

[0032] A high-temperature recirculating flue gas inlet pipe 15 is provided on the high-temperature recirculating flue gas sleeve 14.

[0033] As Figure 3 shown, at the corresponding positions where the tangential swirl inlet pipes of each component are connected, the primary air duct 3, the natural gas duct 6, and the ammonia duct 9 all have reduced sections. The air flow is introduced tangentially into the channel and rotates strongly along the wall under the action of centrifugal force. The reduced structure strengthens the above rotation and forms a swirl to enter the combustion area. The swirl intensity of each fuel component can be adjusted by changing the air intake of the direct current air inlet and the swirl air inlet, realizing stepless adjustment of the swirl intensity.

[0034] In the natural gas - ammonia combustion device of the embodiment, the secondary air comes from preheated hot air, and the high-temperature recirculating flue gas comes from the circulating flue gas at the outlet of the combustion chamber after combustion. Among them, the secondary air directly enters the combustion area through the direct current secondary air inlet pipe 13 to achieve air staged combustion. The high-momentum direct current air can also prevent the combustion flame from sticking to the wall and damaging the burner. The high-temperature recirculating flue gas enters the furnace through the high-temperature recirculating flue gas inlet pipe 15 to avoid the formation of local high-temperature areas.

[0035] Compared with the prior art, the present invention can achieve efficient and clean combustion of natural gas doped with ammonia. Natural gas, ammonia, and primary air are each divided into two streams, a swirling flow and a direct flow, and sent into the combustion chamber. The swirling flow enters the combustion device through a tangential channel, clings to the wall surface, and forms a swirl under the action of inertia and centrifugal force to enter the combustion chamber, thereby obtaining a swirling flow with a certain intensity. The swirling intensity of natural gas should be greater than that of ammonia during the combustion adjustment process to strengthen the entrainment and mixing effect on ammonia fuel, entrain the ammonia fuel into the natural gas rich combustion zone, promote ammonia decomposition, and improve the ammonia combustion effect. The channels for natural gas, ammonia, and primary air can adjust the flow ratio of the direct flow to the swirling flow according to the actual needs of the fuel, and then adjust the swirl number to achieve stepless adjustment of the swirling intensity. Adjusting the swirling intensity can, on the one hand, optimize the mixing of fuels with different reaction characteristics, achieve enhanced natural gas combustion and improved ammonia combustion characteristics, and on the other hand, the highly turbulent swirling flow can entrain the surrounding high-temperature flue gas, extend the residence time of ammonia, and alleviate ammonia escape. In the entire combustion area, since natural gas is easy to ignite and has a high calorific value, it will preferentially react with the oxygen in the primary air to form a local high-temperature and oxygen-deficient area. Ammonia fuel is not easily ignited, and the strongly swirling natural gas can entrain the weakly swirling ammonia into the local high-temperature area formed by natural gas combustion. In this area, due to the high temperature and oxygen deficiency, it can promote the decomposition of ammonia and improve the poor combustion performance of ammonia. The direct-flow secondary air channel is located on the outer layer of the above fuel channels to form air-staged combustion, and the ratio of primary air to secondary air can be flexibly adjusted according to actual needs. The ammonia fuel is divided into two parts, an inner central tube and an ammonia pipe, and sent into the combustion chamber to form staged combustion of ammonia fuel, improve the combustion efficiency, and achieve flexible adjustment of the large-scale ammonia doping condition. The direct-flow secondary air, because it comes from the air preheater, generates a direct flow with a high momentum, thereby restricting the flame expansion angle, preventing flame flashover, avoiding slagging on the wall surface in the area near the burner, and improving the combustion stability. The recirculated flue gas comes from the tail flue gas of boiler combustion, serves as a heat dilution medium, avoids local high temperature, makes the temperature distribution uniform, and reduces the thermal NO x generation.

[0036] The above specific implementation can be locally adjusted by those skilled in the art in different ways without departing from the principles and purposes of the present invention. The protection scope of the present invention is subject to the claims and is not limited by the above specific implementation. All implementation solutions within its scope are subject to the constraints of the present invention.

Claims

1. A combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia, characterized in that, it includes: an inner central tube and a primary air duct assembly, a natural gas duct assembly, an ammonia duct assembly, a secondary air duct assembly, and a recirculation duct assembly sequentially arranged outside it, where: ammonia fuel is introduced into the inner central tube, and the outlet of the inner central tube is arranged at the center of the combustion device housing; natural gas is introduced into the natural gas duct assembly, and the natural gas first undergoes a combustion reaction with the primary air to form a local oxygen-deficient region, and the ammonia fuel is sent into the combustion region in a swirling form and entrained and mixed with the high-temperature flue gas to achieve efficient and clean combustion; the inner central tube, the direct-current secondary air sleeve, and the inlet section of the high-temperature recirculation flue gas sleeve are provided with branch pipes; the primary air duct assembly, the natural gas duct assembly, and the ammonia duct assembly are respectively provided with direct-current air inlet pipes, and the inlet directions of the three direct-current air inlet pipes are at the same angle as the outlet direction of the combustion device; the primary air duct assembly, the natural gas duct assembly, and the ammonia duct assembly are respectively provided with tangential swirling air inlet pipes, and the three tangential swirling air inlet pipes can adjust the swirl intensity by adjusting the ratio of direct-current air to swirling air.

2. The combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia according to claim 1, characterized in that, the primary air duct assembly includes: a primary air duct arranged outside the inner central tube, a direct-current primary air inlet pipe and a tangential swirling primary air inlet pipe arranged on the primary air duct, where: the tangential swirling primary air inlet pipe is arranged tangentially to the main fuel channel.

3. The combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia according to claim 1 or 2, characterized in that, the latter half of the primary air duct is provided with a tapered structure.

4. The combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia according to claim 1, characterized in that, the natural gas duct assembly includes: a natural gas duct arranged outside the primary air duct assembly, a direct-current natural gas inlet pipe and a tangential swirling natural gas inlet pipe arranged on the natural gas duct, where: the tangential swirling natural gas inlet pipe is arranged tangentially to the main fuel channel.

5. The combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia according to claim 1 or 4, characterized in that, the latter half of the natural gas duct is provided with a tapered structure.

6. The combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia according to claim 1, characterized in that, the ammonia duct assembly includes: an ammonia duct arranged outside the natural gas duct assembly, a direct-current ammonia inlet pipe and a tangential swirling ammonia inlet pipe arranged on the ammonia duct, where: the tangential swirling ammonia inlet pipe is arranged tangentially to the main fuel channel.

7. The combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia according to claim 1 or 6, characterized in that, the latter half of the ammonia duct is provided with a tapered structure.

8. The combustion device capable of achieving efficient and clean combustion of natural gas blended with ammonia according to any one of claims 1-7, characterized in that, the three annular spaces formed by the inner central tube and the primary air duct, the primary air duct and the natural gas duct, and the natural gas duct and the ammonia duct are respectively the primary air channel, the natural gas channel, and the ammonia channel.

9. The combustion device capable of realizing efficient and clean combustion of natural gas blended with ammonia according to claim 8, characterized in that, the primary air duct, natural gas duct, and ammonia duct each include an inlet section, a tapered section, and a straight pipe section. The direct current primary air inlet pipe, direct current natural gas inlet pipe, and direct current ammonia inlet pipe are respectively arranged in the corresponding inlet sections; the swirl primary air inlet pipe, swirl natural gas inlet pipe, and swirl ammonia inlet pipe are respectively arranged in the front parts of the corresponding tapered sections; the direct current inlet pipes of each fuel component, namely the direct current primary air inlet pipe, direct current natural gas inlet pipe, and direct current ammonia inlet pipe, are at the same angle with the horizontal direction, which is convenient for the intake setting in actual combustion work. Each component fuel enters from the swirl air inlet pipe, and the initial swirl is generated by the tangential inlet. The reduced section after the inlet section of the swirl air makes the air flow flow at high speed along the wall surface of the tapered section, further strengthening the swirl intensity, enabling the high-degree mixing of each component fuel, increasing the contact time of different component fuels, strengthening the combustion process, and promoting the efficient and stable combustion of the fuel. The swirl intensity of each component fuel can be flexibly adjusted by changing the direct current intake volume and the swirl intake volume.

Images