Efficient composite combustion system for aluminum ash

Abstract

The utility model discloses an efficient composite combustion system for aluminum ash. The efficient composite combustion system comprises a boiler, a turbulent burner and a boiling fluidized bed. The turbulent burner is installed on the side face of the lower portion of a hearth of the boiler, and an outlet faces a middle shaft of the hearth. The swirling burner comprises a natural gas channel, an aluminum ash channel, a combustion-supporting air channel and a pre-combustion chamber, natural gas and aluminum ash are mixed and combusted in the swirling burner, swirling air is formed at an outlet of the pre-combustion chamber, and a combustion state of hedging disturbance is formed in a hearth; high-pressure fluidizing air is introduced into the boiling fluidized bed, a boiling fluidizing combustion state is formed at the bottom of the hearth, secondary combustion is carried out on large-particle and flame-retardant parts left after combustion of the turbulent burner, and efficient combustion of the aluminum ash is achieved. According to the invention, the aluminum ash can be continuously, efficiently and stably combusted, combustible components in the aluminum ash can be fully combusted, harmless and resource utilization of the aluminum ash is finally realized, and meanwhile, heat generated in the combustion process can be output to heat exchange equipment such as a boiler for heat conversion application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of burners and systems for solid waste (including solid hazardous waste) treatment, and particularly relates to a high-efficiency composite combustion system. BACKGROUND

[0002] Aluminum ash is a toxic and harmful solid waste generated in the production process of aluminum industry, and mainly contains aluminum oxide (about 50%), aluminum nitride (about 10%), magnesium oxide (about 10%), calcium oxide (about 0.8%), ferric oxide (about 0.5%), metallic aluminum (about 3%), sulfur (about 0.2%), fluorine (about 2.5%), and other trace elements. The fine particle size is about 50-200 mesh, about 70% of which is fine powder, and the rest is relatively coarse particles with poor uniformity of particle size. The low calorific value is about 800-1300 Kcal / kg, the ignition point is high, it is not easy to ignite, and it is difficult to burn out.

[0003] Aluminum ash treatment mainly has two treatment routes of hydrolysis and combustion. The process route of hydrolysis treatment is relatively complex, and the economic benefit is low. The combustion route mainly adopts a rotary kiln combustion mode, which has low automation degree, low combustion heat utilization rate, large heat loss, and is easy to pollute the environment. At the same time, the aluminum ash has long burning time, low burning rate, and poor combustion continuity. In addition, the system has large heat loss during the combustion process, and the effective utilization rate of combustion heat is very low. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a high-efficiency composite combustion system for aluminum ash, so as to continuously, efficiently and stably combust the aluminum ash, fully burn out the combustible components in the aluminum ash, and finally realize harmless and resource utilization of the aluminum ash. At the same time, the heat generated during the combustion process can be output to a boiler or other heat exchange equipment for heat conversion and application, so as to realize resource utilization of the aluminum ash and produce considerable economic benefits.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A high-efficiency composite combustion system for aluminum ash, comprising a boiler, a swirl burner and a boiling fluidized bed; the swirl burner is installed on the lower side of the hearth of the boiler, and the outlet thereof faces the central axis of the hearth; the boiling fluidized bed is arranged at the bottom of the hearth; the number of the swirl burners is multiple, and the swirl burners are symmetrically installed on the lower side of the hearth of the boiler, and the outlets thereof face the symmetry center;

[0007] The swirl burner comprises a natural gas channel, an aluminum ash channel, a combustion air channel and a pre-combustion chamber, and the natural gas and the aluminum ash are mixed and combusted in the swirl burner; the outlet of the pre-combustion chamber forms a swirling air flow, and a counter-impingement disturbed combustion state is formed in the hearth;

[0008] The high-pressure fluidizing air is introduced into the boiling fluidized bed to form a boiling fluidized combustion state at the bottom of the furnace, and the secondary combustion of the large particles and the non-combustible part left in the cyclone burner is achieved, so that the aluminum ash is efficiently combusted.

[0009] In one embodiment, the cyclone burner further comprises a flue ash channel for feeding flue ash to be mixed and combusted with the natural gas and the aluminum ash.

[0010] In one embodiment, the number of the cyclone burners is four, which are installed in the same plane and divided into two pairs, and the outlets of the pre-combustion chambers of the two cyclone burners in each pair are opposite and located on the same line.

[0011] In one embodiment, the vertical height of the horizontal axis center of the cyclone burner from the bed surface of the boiling fluidized bed is 3-5 times the diameter of the pre-combustion chamber nozzle.

[0012] In one embodiment, the channel is connected with an aluminum ash primary air fan, and a low-temperature air preheater and an aluminum ash bin are arranged on the connecting pipeline, the normal-temperature air output by the aluminum ash primary air fan is heat-exchanged with the flue gas discharged from the boiler through the low-temperature air preheater to output hot air at 100-200 ℃, which drives the aluminum ash falling from the aluminum ash bin to be fed into the cyclone burner through the channel.

[0013] In one embodiment, the combustion-supporting air channel comprises a natural gas combustion-supporting air channel, an inner secondary air channel and an outer secondary air channel, and the combustion-supporting air at 400-500 ℃ after heat-exchange with the flue gas discharged from the boiler through the high-temperature air preheater is provided through the inner secondary air channel and the outer secondary air channel to provide the hot air required for the aluminum ash combustion.

[0014] In one embodiment, the boiling fluidized bed is connected with a high-pressure fluidizing air fan, and a medium-temperature air preheater is arranged on the connecting pipeline, the hot air at 280-350 ℃ after heat-exchange with the flue gas discharged from the boiler through the medium-temperature air preheater is pressurized by the high-pressure fluidizing air fan to be output upward from the boiling fluidized bed to form a boiling fluidized combustion state.

[0015] In one embodiment, the hot flue gas after combustion in the furnace flows to a heat conversion device for waste heat recovery, and the heat conversion device comprises a low-temperature air preheater, a medium-temperature air preheater and a high-temperature air preheater.

[0016] In one embodiment, the channels of the cyclone burner are coaxially arranged, the entrances of the channels are perpendicular to the axis, and the outlets of the channels except the outer secondary air channel are connected to the pre-combustion chamber through a cyclone assembly, and the outlet of the outer secondary air channel is arranged around the outlet of the pre-combustion chamber and is contracted toward the axis.

[0017] The application further provides an efficient composite combustion method based on the efficient composite combustion system, which comprises the following steps:

[0018] The aluminum ash and combustion-supporting wind are mixed in the pre-combustion chamber to ignite, and a swirling wind is formed at the outlet of the pre-combustion chamber to form a counter-flow disturbed combustion state in the furnace.

[0019] The high-pressure fluidization wind is introduced into the boiling fluidized bed to form a boiling fluidized combustion state at the bottom of the furnace, and the secondary combustion is performed on the large particles and difficult-to-burn part of the remaining combustion of the swirling burner, so that the high-efficiency combustion is achieved.

[0020] In an embodiment, the mixed ignition substance in the pre-combustion chamber can also include flue ash, wherein the design combustion amount of the flue ash accounts for 0-25% of the total amount of system fuel, the design combustion amount of the aluminum ash accounts for 40-80% of the total amount of system fuel, and the design combustion amount of the natural gas accounts for 20-60% of the total amount of system fuel. When the design combustion amount of the flue ash accounts for 0 of the total amount of system fuel, it means that the combustion substance does not contain flue ash.

[0021] In an embodiment, the composition of the aluminum ash includes but is not limited to aluminum oxide, aluminum nitride, magnesium oxide, calcium oxide, ferric oxide, metallic aluminum, sulfur, fluorine and trace elements, and the fine particle size is 50-200 mesh, 50-85% of which is fine powder with a particle size ≤90 μm, and the rest is coarse particle with a particle size >90 μm, and the low calorific value is about 800-1300 Kcal / kg.

[0022] The fixed carbon content of the flue ash is 40-65%, the particle size is ≤90 μm, and the calorific value is 3000-4000 Kcal / kg.

[0023] Compared with the prior art, the present application combines the solid powder type swirling burner with the boiling fluidized bed, fully utilizes the advantages of the swirling burner in the forced mixing of solid fine powder type fuel and air for high-efficiency combustion organization, and the characteristics of the boiling fluidized bed in the fluidized combustion organization of low-calorific-value and high-ash-content difficult-to-burn solid particle type fuel, and skillfully combines the two according to certain technical rules to form a set of composite high-efficiency combustion system. The composite combustion system enables the aluminum ash to be continuously, stably, quickly and efficiently combusted, and at the same time stably delivers high-temperature flue gas to the heat energy conversion device combined with the combustion system to realize the efficient utilization of aluminum ash combustion heat energy. The combusted aluminum ash is converted into general solid waste, which can be used as refractory raw material and building material for resource utilization. The composite combustion system realizes the non-polluting treatment of aluminum ash, and at the same time converts the aluminum ash into a resource that can be efficiently utilized. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the overall structure schematic diagram of the high-efficiency composite combustion system of the present application.

[0025] Figure 2 is the structure schematic diagram of the swirling burner of the present application.

[0026] Figure 3 is a schematic diagram of the combustion state of four swirl burners in the furnace to form a counter-jet disturbance in the embodiment of the application.

[0027] Figure 4 is a schematic diagram of the structure of each channel of the swirl burner. DETAILED DESCRIPTION

[0028] The embodiments of the application will be described in detail below with reference to the accompanying drawings and examples.

[0029] To realize the resource utilization and harmless use of aluminum ash, the application provides a high-efficiency composite combustion system, which can realize efficient and continuous and stable combustion of aluminum ash, release a large amount of heat energy to a boiler and other subsequent heat energy conversion equipment, realize the conversion and application of the combustion heat of aluminum ash, and generate corresponding economic benefits. At the same time, the metal aluminum, aluminum nitride and fluorine and other components with hazardous waste characteristics in the aluminum ash after high-temperature combustion can be converted into stable oxides, eliminating the harmfulness to the environment and soil, and can be used as raw materials for refractory materials and building materials for resource utilization and economic value.

[0030] As shown in Figure 1 , Figure 2 and Figure 3 , the application is a high-efficiency composite combustion system of aluminum ash, mainly including a boiler, a swirl burner 4 and a boiling fluidized bed 5. The swirl burner 4 is installed on the lower side of the furnace 6 of the boiler and has an outlet facing the central axis of the furnace 6, so as to spray the combustion flame to the middle, and the boiling fluidized bed 5 is arranged at the bottom of the furnace 6, specifically below the combustion flame sprayed by the swirl burner 4.

[0031] The swirl burner 4 of the application is an integrated multi-mode swirl burner, which has the functions of multiple fuel input and mixed combustion, and in the application, it can burn three combustible substances, i.e., aluminum ash, flue ash and natural gas, alone or simultaneously. Specifically, it at least includes a natural gas channel 9-1, an aluminum ash channel 9-4, a combustion air channel and a pre-combustion chamber 11. The natural gas channel 9-1 is used to send in natural gas, the aluminum ash channel 9-4 is used to send in aluminum ash, the combustion air channel is used to send in combustion air, the natural gas and the aluminum ash are mixed and combusted in the swirl burner 4, and the swirl wind is formed at the outlet of the pre-combustion chamber 11 under the action of the combustion air. When the swirl burner 4 is multiple, the counter-jet disturbance combustion state 12 is formed in the furnace 6.

[0032] Meanwhile, due to the aluminum ash characteristics, the combustion using the cyclone burner 4 alone has the problems of poor stable combustion performance and much slag falling. In view of the problems, the fluidized bed 5 at the bottom of the furnace 6 is used to form a fluidized combustion state at the bottom of the furnace 6 by introducing high-pressure fluidizing air, and the large particles and difficult-to-burn parts of the remaining combustion of the cyclone burner 4 fall into the bottom of the furnace 6 to be combusted again in the fluidized combustion state. Finally, the combination of the cyclone burner 4 and the fluidized bed 5 achieves the effect of efficient combustion of aluminum ash.

[0033] In the present application, the natural gas is used as the gaseous fuel, and the heat value thereof is about 8000 Kcal / Nm 3 , and the natural gas is easy to ignite and burn, so that the natural gas mixed with the aluminum ash can achieve good combustion effect, and the designed combustion amount accounts for about 20% of the total amount of the system fuel, and the highest amount can reach 60%.

[0034] The aluminum ash is used as the combustion and treatment object, and the fine granularity is about 50-200 meshes, about 70% of which is fine powder (about 50-85%), and the rest is relatively coarse particles with a particle size of >90 μm, and the uniformity of the particle size is poor, the low calorific value thereof is about 1050 Kcal / kg, and the general range is 800-1300 Kcal / kg, the ignition point is high, and the aluminum ash is not easy to ignite and burn, and the designed combustion amount accounts for about 40-80% of the total amount of the system fuel, and the general amount can be selected to be more than 70%.

[0035] In view of the above characteristics of the aluminum ash, the present application combines the combustion advantages of the fluidized bed and the cyclone burner to form a combined chamber combustion method in which the cyclone burner 4 is combined with the fluidized bed 5. The fluidized bed 5 has good fuel adaptability and high combustion efficiency, and has obvious advantages in fluidized combustion of low-heat-value, high-ash, and difficult-to-burn solid particle fuels.

[0036] In a further embodiment of the present application, the cyclone burner 4 further comprises a flue ash passage 9-3 for feeding the flue ash to be mixed and combusted with the natural gas and the aluminum ash. Specifically, the flue ash primary fan 1-2 is designed, and the outlet of the flue ash bin 3-1 is arranged on the outlet pipeline of the flue ash primary fan 1-2, the normal-temperature air output by the flue ash primary fan 1-2 drives the high-temperature flue ash falling from the flue ash bin 3-1, and the flue ash is conveyed to the flue ash passage 9-3 of the cyclone burner 4 through the corresponding conveying pipeline. Similarly, the aluminum ash primary fan 1-1 is designed, and the outlet of the aluminum ash bin 2-1 is arranged on the outlet pipeline of the aluminum ash primary fan 1-1, the air output by the aluminum ash primary fan 1-1 drives the aluminum ash falling from the aluminum ash bin 2-1, and the aluminum ash is conveyed to the aluminum ash passage 9-4 of the cyclone burner 4 through the corresponding conveying pipeline.

[0037] The fixed carbon content of the flue ash is about 50%, generally in the range of 40-65%, and the solid ultrafine powder has a particle size of about 200 mesh, a particle size of ≤90 μm, and a calorific value of about 3000-3600 Kcal / kg, which can be as high as 4000 Kcal / kg under certain conditions. The flue ash is easy to ignite and burn, and the designed combustion amount accounts for about 10% of the total amount of fuel in the system. By adding the flue ash, the high calorific value and easy combustion of the flue ash can be used to play a combustion-supporting role in the system.

[0038] In addition, the present application adopts three kinds of fuels, i.e., natural gas, aluminum ash and flue ash, and the integrated multi-mode rotational flow burner can burn natural gas fuel alone or burn natural gas mixed with another or two kinds of solid fuels. The combustion ratio of the three kinds of fuels and the thermal power can be designed in detail according to the requirements.

[0039] Figure 2 The structure of the integrated multi-mode rotational flow burner of the present application is shown in the structural schematic view, which mainly includes an ignition device 9-7, a natural gas passage 9-1, a natural gas combustion-supporting air passage 9-2, a flue ash passage 9-3, an aluminum ash passage 9-4, an inner secondary air passage 9-5, an outer secondary air passage 9-6 and an anti-coking pre-combustion chamber 11. In the multi-passage structure, the ignition device 9-7 is located at the center of the burner and is used for initial ignition of the burner. After the ignition lance head is stably ignited, natural gas is introduced into the natural gas passage 9-1, and the flame of the ignition lance head ignites the natural gas in the natural gas passage 9-1. After the natural gas in the natural gas passage 9-1 is stably combusted, the amount of the natural gas is adjusted to a suitable amount according to the heating speed of the boiler and the size of the boiler, and is used for overall heating of the boiler. At the same time, the dampers of the inner secondary air passage 9-5 and the outer secondary air passage 9-6 are adjusted to a suitable position, so that the oxygen content at the outlet of the furnace is maintained between 5% and 10%. A small amount of air is introduced into the flue ash passage 9-3 and the aluminum ash passage 9-4 to cool and protect the flue ash and aluminum ash passages. After the natural gas is combusted for a period of time, the temperature of the furnace is observed. When the furnace reaches a certain high temperature and is stable for a period of time, a small amount of aluminum ash is added, the temperature of the furnace is observed, and the amount is slowly increased. The temperature continues to rise, and the aluminum ash is slowly added under this condition until the designed amount or the actual output of the boiler is reached. The integrated multi-mode rotational flow burner is used together with the furnace when combusted, and the furnace 6 is an integral part of the combustion system.

[0040] The natural gas combustion air passage 9-2 provides a large amount of air for the combustion of natural gas at the initial stage. When the boiler is normally combusting, the amount of natural gas combustion is reduced or disabled, and the natural gas combustion air passage 9-2 only needs to pass a small amount of cooling anti-blocking purge air. The secondary air in the inner secondary air passage 9-5 is high-temperature air with a temperature of 400-500℃. The inner secondary air passage 9-5 includes two passages, namely, an inner secondary air straight-flow air passage and an inner secondary air rotational-flow air passage. The inner secondary air straight-flow air passage and the inner secondary air rotational-flow air passage adjust the flame diameter and length according to the needs, and when the temperature of the precombustion chamber 11 and the boiler furnace is low (≤850℃), the inner secondary air straight-flow air passage is closed and the inner secondary air rotational-flow air passage is opened, so that the flame is ignited and combusted in the precombustion chamber 11 as much as possible at the secondary air outlet of the burner. When the temperature of the precombustion chamber 11 and the boiler furnace is high (≥1050℃), the inner secondary air straight-flow air passage is opened and the inner secondary air rotational-flow air passage is appropriately closed, so that the combustion flame is long and a part of the combustion flame is combusted in the precombustion chamber 11 and a part of the combustion flame is combusted in the boiler furnace. According to the combustion characteristics that the combustion is not combusted at a low temperature and the combustion is fully combusted at a high temperature, a certain high-temperature environment is ensured for combustion. In the design of the burner, the high-temperature secondary air is arranged at a position close to the aluminum ash passage 9-4, so that the primary air is mixed with the secondary air after being sprayed out, the combustion temperature is quickly increased, and the combustion is stably combusted. Meanwhile, the precombustion chamber 11 is designed to combust at the secondary air outlet, and the heat after combustion is gathered in the small precombustion chamber 11, so that the flue gas temperature in the precombustion chamber 11 is increased, and the temperature is ensured for combustion. The burner is designed with an outer secondary air passage 9-6. The outer secondary air passage 9-6 is high-temperature air with a low temperature, and the outlet is arranged at the end surface of the precombustion chamber 11 and at a position far from the aluminum ash passage 9-4, so as to provide part of oxygen for the combustion in the boiler furnace.

[0041] In a further embodiment of the present application, when the number of rotational-flow burners 4 is multiple, the rotational-flow burners 4 are symmetrically installed at the center of the lower side of the furnace 6, and the outlets of the rotational-flow burners 4 are all directed to the center, so as to disturb the combustion state 12. Figure 1 and Figure 3 In the structure shown in the figure, the number of rotational-flow burners 4 is four, two rotational-flow burners 4 are installed on each of the two side walls of the lower part of the furnace 6, and the four rotational-flow burners 4 are installed on the same plane and are divided into two pairs. The outlets of the two rotational-flow burners 4 in each pair are opposite to each other and located on the same straight line, so as to disturb the combustion state 12. In actual application, the number of rotational-flow burners 4 and the area of the boiling fluidized bed 5 are adjusted according to the total amount of aluminum ash combustion design.

[0042] In a further embodiment of the present application, the vertical height of the center of the horizontal axis of the rotational-flow burner 4 from the bed surface of the boiling fluidized bed 5 is 3-5 times the diameter of the precombustion chamber 11, and the height can ensure that the particles combusted by the rotational-flow burner 4 are quickly combusted again by the boiling fluidized bed 5.

[0043] In a further embodiment of the present application, the aluminum ash channel 9-4 is connected to the aluminum ash primary air fan 1-1, and a low-temperature air preheater 7-1 and an aluminum ash bin 2-1 are arranged on the connecting pipeline. The normal-temperature air output by the aluminum ash primary air fan 1-1 exchanges heat with the boiler exhaust flue gas through the low-temperature air preheater 7-1, and outputs hot air at 100-200°C to drive the aluminum ash falling from the aluminum ash bin 2-1, which is sent into the cyclone burner 4 through the aluminum ash channel 9-4.

[0044] In a further embodiment of the present application, the combustion-supporting air channel includes a natural gas combustion-supporting air channel 9-2, an inner secondary air channel 9-5, and an outer secondary air channel 9-6. The natural gas combustion-supporting air channel 9-2 is arranged after the outlet of the natural gas channel 9-1, before the flue ash channel 9-3 and the aluminum ash channel 9-4. The natural gas and the natural gas combustion-supporting air are mixed in the precombustion chamber 11 through the natural gas channel 9-1 and the natural gas combustion-supporting air channel 9-2, ignited by the ignition device 9-7, and then ignite the flue ash and the aluminum ash (or the aluminum ash alone), to start efficient combustion in the cyclone burner 4. The 400-500°C combustion-supporting air after heat exchange with the boiler exhaust flue gas through the high-temperature air preheater 7-3 provides hot air required for aluminum ash combustion through the inner secondary air channel 9-5 and the outer secondary air channel 9-6, to form a strong cyclone air at the outlet of the precombustion chamber 11.

[0045] In a further embodiment of the present application, the boiling fluidized bed 5 is connected to the high-pressure fluidizing fan 1-4, and a medium-temperature air preheater 7-2 is arranged on the connecting pipeline. The 280-350°C hot air after heat exchange with the boiler exhaust flue gas through the medium-temperature air preheater 7-2 is pressurized by the high-pressure fluidizing fan 1-4, and is output upward from the boiling fluidized bed 5 to form a boiling fluidized combustion state.

[0046] In a further embodiment of the present application, the furnace 6 is a space for organizing the intensified combustion of the cyclone burner 4 and the boiling fluidized bed 5, and continuously and rapidly burning the aluminum ash at a high temperature of 1000°C or above, so that the aluminum ash is converted from hazardous waste to general solid waste, which can be used as refractory and building raw materials. In this space, the aluminum ash releases a large amount of heat energy outward, the boiler cylinder absorbs the heat and delivers it to the application workshop, generating corresponding economic benefits. The hot flue gas after combustion in the furnace 6 flows to the heat conversion device for waste heat recovery, and then passes through the subsequent flue gas environmental protection treatment device, and finally reaches the chimney for emptying. After high-temperature combustion in the furnace 6, the aluminum ash generates stable oxides, eliminating the harmfulness of the aluminum ash raw material to the environment and soil, and can be used as raw materials for refractory materials and building materials for resource recycling and continue to play economic value.

[0047] The heat conversion device comprises a low-temperature air preheater 7-1, a medium-temperature air preheater 7-2 and a high-temperature air preheater 7-3. The low-temperature air preheater 7-1 is installed on the outlet pipeline of the aluminum ash primary air fan 1-1, and the normal-temperature air output by the aluminum ash primary air fan 1-1 exchanges heat with the boiler exhaust flue gas through the low-temperature air preheater 7-1, and outputs hot air at 100-200 DEG C, which drives the aluminum ash falling from the aluminum ash bin 2-1, on the one hand, realizes the conveying to the aluminum ash channel 9-4, and on the other hand, realizes the preheating of the aluminum ash. The application utilizes the high-pressure fluidization fan 1-4 to convey air to the medium-temperature air preheater 7-2, and the medium-temperature air preheater 7-2 exchanges heat with the boiler exhaust flue gas to form high-temperature air at 280-350 DEG C, and forms a boiling fluidized combustion state at the lower part of the furnace 6 of the boiler. The application utilizes the secondary air fan 1-3 to convey air to the high-temperature air preheater 7-3, and the high-temperature air preheater 7-3 exchanges heat with the boiler exhaust flue gas to form hot air at 400-500 DEG C, and then the hot air is distributed through the secondary air distribution box 8, and is provided to the natural gas combustion-supporting air channel 9-2, the inner secondary air channel 9-5, the outer secondary air channel 9-6 and the boiler burnout air nozzle 10 at the upper part of the furnace 6.

[0048] The processing flow and chemical reaction formula of aluminum ash in the aluminum ash composite high-efficiency combustion system are as follows:

[0049] Primary aluminum ash or secondary aluminum ash collected by processing is conveyed to the aluminum ash bin 2-1 in front of the boiler, and is conveyed to the cyclone burner 4 through the aluminum ash feeding device 2-2 at the lower part of the aluminum ash bin 2-1 and the aluminum ash primary air fan 1-1 by air force, air distribution and combustion are carried out in the cyclone burner 4, the combustion flame and flue gas enter the furnace 6 for heat exchange, the heavy mass and large particle aluminum ash falls on the boiling fluidized bed 5 at the bottom of the furnace 6 for secondary combustion, the burned-out fly ash is collected through the boiler tail dust collector, and the boiler bottom ash is collected through the dry-type slag cooler, and the ash is sold to a building material enterprise.

[0050] The aluminum ash components, such as metallic aluminum (AI) and aluminum nitride (AlN), have the characteristics of hazardous waste, and the main component generated after high-temperature combustion is harmless aluminum oxide (Al2O3), which can become a high-quality raw material for refractory materials, water permeable bricks, water purifying agents, calcium aluminate and other products, and some reaction formulas are as follows:

[0051] 4Al + 3O2 = 2Al2O3

[0052] 4AlN + 3O2 = 2Al2O3 + 2N2

[0053] 4Al2C3 + 6O2 = 2Al2O3 + 3CO2

[0054] The current aluminum ash combustion route mainly adopts the rotary kiln furnace mode, and the combustion mode has low aluminum ash burning rate, poor combustion continuity, large heat loss in the combustion process, and very low effective utilization rate of combustion heat.

[0055] The composite high-efficiency combustion system of the present application is a system combining a swirl burner and a boiling fluidized bed, which has strong mixing, stable high-efficiency combustion, full utilization of waste heat energy, and recyclable combustion residues, and can effectively solve the problems of insufficient mixing, low combustion efficiency and waste of waste heat in the current aluminum ash combustion.

[0056] In more embodiments of the present application, the aluminum ash high-efficiency composite combustion system includes but is not limited to the system process and equipment configuration directly disclosed in this patent, and also includes design variations based on the system process principle disclosed in this patent. For example, the furnace 6 in the present system can be a vertical structure or a horizontal structure; the swirl burner 4 can be designed into a single mode, a double mode, or other structural forms and corresponding functions according to the type of combustible material.

Claims

1. An efficient combined combustion system of aluminum ash characterized in that, The application relates to a high-efficiency aluminum ash boiler, which comprises a boiler, a swirl burner (4) and a boiling fluidized bed (5); the swirl burner (4) is arranged on the lower side of the furnace (6) of the boiler and has an outlet directed to the central axis of the furnace (6); the boiling fluidized bed (5) is arranged on the bottom of the furnace (6); the swirl burners (4) are arranged in a plurality of numbers and are symmetrically arranged on the lower side of the furnace (6) of the boiler and have outlets directed to the symmetry center. The swirl burner (4) comprises a natural gas channel (9-1), an aluminum ash channel (9-4), a combustion-supporting air channel and a pre-combustion chamber (11); the natural gas and the aluminum ash are mixed and combusted in the swirl burner (4); the pre-combustion chamber (11) forms a swirl air outlet and forms a counter-interference combustion state (12) in the furnace (6). The boiling fluidized bed (5) introduces high-pressure fluidizing air to form a boiling fluidized combustion state on the bottom of the furnace (6) and to perform secondary combustion on the large particles and non-combustible parts left by the swirl burner (4), so that the aluminum ash is efficiently combusted.

2. The efficient combined cycle system for aluminum dross combustion according to claim 1, wherein, The swirl burner (4) further comprises a flue ash channel (9-3) for feeding flue ash to be mixed and combusted with the natural gas and the aluminum ash.

3. The efficient combined cycle system for the combustion of aluminum ash according to claim 1, wherein, The swirl burners (4) are arranged in four numbers and are arranged on the same plane and are divided into two pairs; the pre-combustion chambers (11) of the two swirl burners (4) of each pair are oppositely arranged and are arranged on the same straight line.

4. The efficient combined cycle system for aluminum dross combustion according to claim 1 or 2 or 3, wherein, The vertical height of the horizontal axis center of the swirl burner (4) from the bed surface of the boiling fluidized bed (5) is 3-5 times the diameter of the pre-combustion chamber (11).

5. The efficient co-combustion system of aluminum ash according to claim 1, wherein, The hot flue gas after combustion in the furnace (6) flows to a heat conversion device for waste heat recovery; the heat conversion device comprises a low-temperature air pre-heater (7-1), a medium-temperature air pre-heater (7-2) and a high-temperature air pre-heater (7-3).

6. The efficient combined cycle system for the combustion of aluminum ash according to claim 5, wherein, The aluminum ash channel (9-4) is connected with an aluminum ash primary air fan (1-1) and a low-temperature air pre-heater (7-1) and an aluminum ash bin (2-1) are arranged on the connecting pipeline; the normal-temperature air output by the aluminum ash primary air fan (1-1) is heat-exchanged with the flue gas discharged from the boiler through the low-temperature air pre-heater (7-1) to output hot air at 100-200 DEG C, which drives the aluminum ash falling from the aluminum ash bin (2-1) to be fed into the swirl burner (4) through the aluminum ash channel (9-4).

7. The efficient combined cycle system for the combustion of aluminum ash according to claim 5, wherein, The combustion-supporting air channel comprises a natural gas combustion-supporting air channel (9-2), an inner secondary air channel (9-5) and an outer secondary air channel (9-6); the combustion-supporting air at 400-500 DEG C after heat exchange with the flue gas discharged from the boiler through the high-temperature air pre-heater (7-3) is provided to the aluminum ash combustion through the inner secondary air channel (9-5) and the outer secondary air channel (9-6).

8. The efficient combined cycle system for the combustion of aluminum ash according to claim 5, wherein, The boiling fluidized bed (5) is connected with a high-pressure fluidizing air fan (1-4) and a medium-temperature air pre-heater (7-2) is arranged on the connecting pipeline; the hot air at 280-350 DEG C after heat exchange with the flue gas discharged from the boiler through the medium-temperature air pre-heater (7-2) is pressurized by the high-pressure fluidizing air fan (1-4) and is output upward from the boiling fluidized bed (5) to form a boiling fluidized combustion state.

9. The efficient combined cycle system for the combustion of aluminum ash according to claim 1, wherein, The swirl burner (4) comprises channels arranged coaxially, the inlet of each channel being perpendicular to the axis, the outlet of each channel, except the secondary air channel (9-6), being connected to the pre-chamber (11) through a swirl assembly, the outlet of the secondary air channel (9-6) being arranged around the outlet of the pre-chamber (11) and being contracted towards the axis.

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