Porous medium stable combustion and cold and hot atomization cooperated coal water slurry burner and use method thereof

Abstract

The invention discloses a porous medium stable combustion and cold and hot atomization cooperated coal water slurry burner and a use method thereof, and relates to the technical field of coal slurry combustion. The technical problems that an existing coal water slurry burner is low in combustion efficiency, unstable in combustion and high in pollutant emission due to uneven atomization are solved. The coal water slurry burner comprises a burner head, a neck tube and a porous medium accommodating tube, the burner head comprises a coal water slurry pipe, an ultralow-temperature gas pipe and a high-temperature steam pipe; the high-temperature steam pipe is communicated with the porous medium accommodating pipe; an inner cavity of the coal water slurry pipe is a coal water slurry channel; an ultralow-temperature gas channel and a high-temperature steam channel are respectively formed between the ultralow-temperature gas pipe and the coal water slurry pipe and between the ultralow-temperature gas pipe and the high-temperature steam pipe; a first mixing cavity and a second mixing cavity are respectively formed between the outlet end of the ultralow-temperature gas pipe and the outlet ends of the coal water slurry pipe and the high-temperature steam pipe; a third mixing cavity is formed in the neck tube; a gradient porous medium body assembly is arranged in the porous medium containing pipe. The invention further provides a using method of the burner.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal slurry combustion, and in particular to a porous medium stable combustion and cold-hot atomization synergetic coal water slurry burner and a use method thereof. BACKGROUND

[0002] The atomization technology of the coal water slurry burner mainly sprays the coal water slurry into the furnace through the atomization device to form small droplets so as to be fully mixed with air and achieve combustion. The atomization effect directly affects the quality of coal combustion and emission control. Therefore, research and improvement of the atomization technology of the coal water slurry become the key to improve the combustion performance of the coal water slurry.

[0003] The function of the coal water slurry burner is to efficiently atomize the coal water slurry (mixed by coal powder, water and additives) and mix with the oxidant to achieve stable combustion or gasification reaction. The existing coal water slurry burner has the following disadvantages: low combustion efficiency, unstable combustion and high pollutant emission due to uneven atomization. SUMMARY

[0004] Embodiments of the present application provide a porous medium stable combustion and cold-hot atomization synergetic coal water slurry burner and a use method thereof, which solve the technical problems of low combustion efficiency, unstable combustion and high pollutant emission of the existing coal water slurry burner due to uneven atomization.

[0005] To achieve the above-mentioned purpose, on the one hand, embodiments of the present application provide a porous medium stable combustion and cold-hot atomization synergetic coal water slurry burner, which comprises a burner head, a neck pipe and a porous medium containing pipe arranged in sequence along the axial direction; the burner head comprises a coal water slurry pipe, an ultra-low temperature gas pipe and a high temperature steam pipe which are sequentially sleeved from inside to outside; the high temperature steam pipe is connected with the porous medium containing pipe through the neck pipe; the inner cavity of the coal water slurry pipe is a coal water slurry passage; an ultra-low temperature gas passage is formed between the coal water slurry pipe and the ultra-low temperature gas pipe; a high temperature steam passage is formed between the ultra-low temperature gas pipe and the high temperature steam pipe; a first mixing cavity is formed between the outlet end of the coal water slurry pipe and the outlet end of the ultra-low temperature gas pipe; a second mixing cavity is formed between the outlet end of the ultra-low temperature gas pipe and the outlet end of the high temperature steam pipe; the inner cavity of the neck pipe is a third mixing cavity; a gradient porous medium body assembly is arranged in the porous medium containing pipe.

[0006] Further, the end face of the outlet end of the ultra-low temperature gas pipe is higher than the end face of the outlet end of the coal water slurry pipe and lower than the end face of the outlet end of the high temperature steam pipe.

[0007] Further, the gradient porous medium body assembly comprises a first porous medium body, a second porous medium body and a third porous medium body arranged in sequence along the axial direction; the second porous medium body is two; the first porous medium body is arranged close to the third mixing cavity; the first porous medium body is processed by using a material with a high-temperature-resistant and high-heat-conducting large-pore octahedral structure; the second porous medium body is processed by using a material with a high-temperature-resistant and high-heat-conducting Voronoi random pore structure; and the third porous medium body is processed by using a material with a high-temperature-resistant and high-heat-conducting small-pore tetradecahedral structure.

[0008] Further, the first porous medium body, the second porous medium body and the third porous medium body are all coated with an oleophobic metal oxide coating.

[0009] Further, the length of the first mixing cavity is 1 / 3 of the length of a conventional coal slurry burner mixing cavity.

[0010] Further, the super-low-temperature gas passage is used for super-low-temperature gas to flow through; the high-temperature steam passage is used for high-temperature and high-pressure steam to flow through; the super-low-temperature gas can pre-cool and break the coal water slurry, and weaken the shear resistance of the coal water slurry; and the high-temperature and high-pressure steam can impact the pre-cooled and broken coal water slurry at a high speed, and improve the atomization characteristics of the coal water slurry.

[0011] Further, the super-low-temperature gas is liquid nitrogen evaporation gas or liquid carbon dioxide evaporation gas; and the high-temperature and high-pressure steam is a gas with a temperature greater than 200℃ and a pressure greater than 0.8Mpa.

[0012] In another aspect, the embodiment of the present application also provides a use method of the above-mentioned coal water slurry burner with the gradient porous medium stable combustion and cold-hot atomization synergy, comprising the following steps: S1, pre-treating and mixing the coal water slurry to be introduced into the coal water slurry passage, to ensure that the coal water slurry can smoothly enter the coal water slurry passage; S2, introducing the coal water slurry into the coal water slurry passage, and introducing the super-low-temperature gas into the super-low-temperature gas passage, to pre-cool the coal water slurry in the first mixing cavity until the coal water slurry forms a "gel" state; S3, introducing the high-temperature and high-pressure steam into the high-temperature steam passage, to perform secondary atomization on the coal water slurry in the "gel" state in the second mixing cavity, and to disperse the coal water slurry into fine particles; S4, uniformly reacting the coal water slurry atomized particles obtained in step S3 with air in the third mixing cavity; and S5, introducing the coal water slurry atomized particles obtained in step S4 into the gradient porous medium body assembly, to perform multi-stage filtration and separation.

[0013] Further, the super-low-temperature gas is liquid nitrogen evaporation gas or liquid carbon dioxide evaporation gas; and the high-temperature and high-pressure steam is a gas with a temperature greater than 200℃ and a pressure greater than 0.8Mpa.

[0014] Further, the flow rate of the super-low-temperature gas is 15-20m / s; and the flow rate of the high-temperature and high-pressure steam is 30-35m / s.

[0015] The present application has the following beneficial effects compared with the prior art:

[0016] 1. The gradient porous medium body assembly in the porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment can effectively and uniformly distribute fuel and provide more stable combustion conditions, thereby avoiding the unstable flame or flameout phenomenon that is prone to occur in traditional burners.

[0017] 2. The porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment combines cold and hot atomization technology, so that the coal water slurry can be more uniformly atomized and mixed with air, and the synergistic effect of cold and hot atomization helps to improve the combustion efficiency of fuel, reduce heat loss, and improve thermal efficiency.

[0018] 3. The porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment controls the particle size of the coal water slurry through cold atomization technology, ensures complete combustion of the fuel, thereby improving the utilization rate of the fuel, reducing the residue of incomplete combustion, and reducing pollutant emissions.

[0019] 4. The porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment enhances the wear resistance and service life of the burner by combining porous media and cold and hot atomization technology, reduces the frequency and cost of system maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 It is a perspective structural schematic diagram of the porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment.

[0022] Figure 2 It is a sectional view of the porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment.

[0023] Figure 3 It is a structural schematic diagram of the large-pore octahedral structure in the porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment.

[0024] Figure 4 It is a structural schematic diagram of the Voronoi random pore structure in the porous medium stable combustion synergistic cold and hot atomization coal water slurry burner of the present application embodiment.

[0025] Figure 5A structure diagram of a small hole tetrahedron structure in a porous medium stable combustion and cold-hot atomization coordinated water coal slurry burner in the embodiments of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0027] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation to the present application.

[0028] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; for those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0030] The embodiments of the present application provide a porous medium stable combustion and cold-hot atomization coordinated water coal slurry burner, which optimizes the atomization effect of water coal slurry by super-low temperature gas pre-cooling crushing + high temperature steam secondary atomization, thereby improving the combustion efficiency and reducing the emission of pollutants, and at the same time, by using the stable combustion technology of porous medium, the combustion process is more stable.

[0031] Reference Figure 1 and Figure 2 The porous medium stable combustion and cold-hot atomization coordinated water coal slurry burner in the embodiments of the present application comprises a burner head 1, a neck pipe 2 and a porous medium containing pipe 3 arranged in sequence along the axial direction.

[0032] The burner head 1 comprises a water coal slurry pipe 11, an ultra-low temperature gas pipe 12 and a high temperature steam pipe 13 which are sequentially sleeved from inside to outside.

[0033] The high temperature steam pipe 13 is connected with the porous medium containing pipe 3 through the neck pipe 2. The gradient porous medium body assembly 4 is arranged in the porous medium containing pipe 3.

[0034] The inner cavity of the water coal slurry pipe 11 is a water coal slurry passage 14 for the water coal slurry to flow through.

[0035] The ultra-low temperature gas passage 15 is formed between the water coal slurry pipe 11 and the ultra-low temperature gas pipe 12 for the ultra-low temperature gas to flow through. The ultra-low temperature gas can be liquid nitrogen evaporation gas or liquid carbon dioxide evaporation gas. The liquid nitrogen evaporation gas is the first choice, which is widely available and safe, and the temperature can be as low as about -196℃ at normal pressure. The liquid carbon dioxide evaporation gas is also a common choice, with a temperature of about -78.5℃, which is a combustion product itself and can help carbon capture. It should be noted that the liquid medium should be completely gasified during use, and the outlet temperature should be controlled between -50℃ and -100℃. Too low temperature can cause coal slurry to freeze and block, while too high temperature can weaken the effect. In addition, by adjusting the pressure and flow of the gasifier, the gas temperature can be accurately controlled. The flow is usually 1 / 10 to 1 / 5 of the main atomizing steam flow to ensure the cooling effect without diluting or taking away a large amount of heat.

[0036] The high temperature steam passage 16 is formed between the ultra-low temperature gas pipe 12 and the high temperature steam pipe 13 for the high temperature and high pressure steam to flow through. The high temperature and high pressure steam is a gas with a temperature greater than 200℃ and a pressure greater than 0.8Mpa.

[0037] The end face of the outlet end (right end) of the ultra-low temperature gas pipe 12 is higher than the end face of the outlet end (right end) of the water coal slurry pipe 11 and lower than the end face of the outlet end (right end) of the high temperature steam pipe 13.

[0038] The first mixing cavity 17 is formed between the outlet end of the water coal slurry pipe 11 and the outlet end of the ultra-low temperature gas pipe 12. The length of the first mixing cavity 17 is 1 / 3 of the mixing cavity of the traditional coal slurry burner. The second mixing cavity 18 is formed between the outlet end of the ultra-low temperature gas pipe 12 and the outlet end of the high temperature steam pipe 13. The inner cavity of the neck pipe 2 is the third mixing cavity 19.

[0039] The outlet end of the water coal slurry pipe 11 is provided with a first outer tapered surface. The outlet end of the ultra-low temperature gas pipe 12 is provided with a second outer tapered surface and a first inner tapered surface. The outlet end of the high temperature steam pipe 13 is provided with a second inner tapered surface. Each tapered surface can play a guiding role to guide the fluid into the second mixing cavity 18 and the third mixing cavity 19, and can also accelerate the flow rate of the fluid.

[0040] The gradient porous medium body assembly 4 is a gradient porous medium structure with high temperature resistance, high thermal conductivity and high porosity, which comprises a first porous medium body 41, a second porous medium body 42 and a third porous medium body 43 arranged in sequence along the axial direction. The second porous medium body 42 is two. Since the gradient porous structure can effectively alleviate the thermal shock caused by the sharp change of temperature, the gradient porous medium body assembly 4 can ensure that the combustion of fuel remains stable even in a high temperature environment through high thermal conductivity, high temperature resistance and sufficient porosity.

[0041] The first porous medium body 41 is arranged close to the third mixing cavity 19, i.e. at the inlet of the porous medium containing pipe 3. Referring to Figure 3 , the first porous medium body 41 is processed by using a material with a large-pore octahedral structure which is temperature-resistant and has high thermal conductivity. The large-pore octahedral structure can effectively trap large-particle substances and reduce their entry into the subsequent combustion area. In this way, not only can the influence of large-particle substances on the combustion process be avoided, but also the instability of fuel in the combustion process can be effectively alleviated.

[0042] The second porous medium body 42 is located in the middle of the porous medium containing pipe 3. Referring to Figure 4 , the second porous medium body 42 is processed by using a material with a Voronoi random pore structure which is temperature-resistant and has high thermal conductivity. The random pore structure can effectively increase the contact area between gas and liquid, thereby promoting the rapid evaporation of moisture and avoiding the adverse effects of liquid aggregation on the combustion temperature. Thus, the evaporation effect can be further enhanced by the randomly distributed pores.

[0043] The third porous medium body 43 is located at the outlet of the porous medium containing pipe 3. Referring to Figure 5 , the third porous medium body 43 is processed by using a material with a small-pore tetrakaidecahedron structure which is temperature-resistant and has high thermal conductivity. The design of small pores can ensure that the fuel is gradually and fully combusted during the combustion process, while controlling the flame shape to ensure that the fuel completes the combustion process stably.

[0044] In summary, the pore size of the gradient porous medium body assembly 4 gradually changes from the inlet to the outlet, forming a gradient structure which can help to effectively trap large-particle dust while ensuring that small particles enter the area with smaller pore size for stable combustion.

[0045] Specifically, the first porous medium body 41, the second porous medium body 42 and the third porous medium body 43 are all processed by using SiC (silicon carbide) foam ceramic material. SiC (silicon carbide) foam ceramic has excellent high temperature resistance and thermal conductivity. SiC foam ceramic not only can maintain structural stability at extremely high temperatures, but also has high thermal conductivity, which can quickly transfer heat. In addition, SiC material has a low thermal expansion coefficient and high corrosion resistance, which is suitable for long-term use in high temperature environments.

[0046] In addition, the first porous medium body 41, the second porous medium body 42 and the third porous medium body 43 can also be coated with an oleophobic metal oxide coating. The coating can effectively prevent the accumulation of dirt such as oil, reduce deposits in the combustion process and improve combustion efficiency and equipment life.

[0047] The working principle of the water coal slurry burner with the porous medium stable combustion and synergistic cold and hot atomization according to the embodiments of the present application is as follows:

[0048] The water coal slurry and the ultra-low temperature gas are mixed in the first mixing chamber 17. The ultra-low temperature gas can pre-cool the water coal slurry, making the coal slurry brittle instantaneously and greatly increasing its viscosity, thereby weakening the shear resistance of the coal slurry, making the subsequent steam atomization more effective and further optimizing the combustion effect.

[0049] It should be noted that the contact mode of the coal slurry and the ultra-low temperature gas is very critical in the pre-cooling process, which is to preliminarily mix the ultra-low temperature gas and the coal slurry in the nozzle mixing chamber. The first mixing chamber 17 in the embodiments of the present application is shortened by 2 / 3 compared with the traditional water coal slurry burner mixing chamber, which can cool the surface or local area of the coal slurry intensively, thereby forming a "brittle outside and soft inside" state, avoiding internal freezing to cause blockage, and when the surface of the coal slurry is cooled, the surface viscosity increases greatly, the apparent viscosity of the slurry body increases instantaneously, and a brittle state similar to "frozen glue" is presented. At the same time, a brittle "shell" is formed on the surface or micro-cracks are generated, and the thermal shrinkage stress generated inside will weaken the structural strength of the coal slurry, thereby creating conditions for subsequent high-temperature steam atomization.

[0050] The pre-cooled water coal slurry enters the second mixing chamber 18 to mix with high-temperature and high-pressure steam for high-temperature steam secondary atomization. The high-temperature and high-pressure steam can impact the pre-cooled and brittle coal slurry at high speed, improve the atomization characteristics of the coal slurry, greatly increase the combustion surface area of the coal slurry, and thereby improve the combustion efficiency and stability.

[0051] Specifically, since the speed of high-temperature steam secondary atomization is very fast, the high-temperature and high-pressure steam will impact the pre-cooled and brittle coal slurry flow at high speed. At this time, the high-speed steam exerts a huge shear force on the brittle coal slurry, making it easy to be torn into small droplets. In addition, thermal shock will also cause the surface of the coal slurry droplet to expand sharply, while the inside shrinks due to maintaining low temperature, thereby generating a huge stress difference, prompting the droplet to "explode" from the inside or stress concentration point, realizing thermal fragmentation. The high-temperature steam not only provides a large amount of sensible heat to accelerate the evaporation of water in the coal slurry droplet, but also greatly improves the drying rate and shortens the ignition time.

[0052] Since the nozzle needs to withstand severe temperature cycling and thermal stress, a special alloy Inconel 625 material resistant to low-temperature brittle, high-temperature oxidation and thermal fatigue should be selected, and the thermal barrier design should be optimized.

[0053] In summary, the high-viscosity coal water slurry is pre-cooled and broken by ultra-low temperature gas before entering the combustion system. The purpose of this step is to rapidly reduce the temperature of the coal water slurry, so that the large particles and relatively hard substances in the slurry are effectively broken, thereby improving the efficiency and uniformity of heat exchange in the subsequent process. In addition, low-temperature breaking can prevent the viscosity of the coal water slurry from being too high, which can cause poor flowability under high-temperature conditions, thereby affecting the combustion efficiency and stability. When the broken coal water slurry is atomized by high-temperature steam, the high temperature and pressure of the steam can promote the dispersion of the coal water slurry droplets into small particles in an instant. This atomization effect helps to increase the surface area of the fuel, thereby promoting the mixing of oxygen and fuel during the combustion process. This process can also accelerate the evaporation of water in the coal water slurry, reducing the fuel components in liquid form, thereby improving the thermal efficiency and stability of the subsequent combustion process.

[0054] After the coal water slurry is atomized by high-temperature steam for the second time, it enters the third mixing chamber 19. Due to the suitable temperature and pressure conditions in the mixing chamber, the coal water slurry can uniformly react with air during this process, further improving the stability and efficiency of combustion.

[0055] The coal water slurry flowing out of the third mixing chamber 19 first passes through the first porous medium body 41 for primary filtration and separation, and large particle substances and impurities are effectively intercepted to prevent them from entering the subsequent combustion area, reducing the negative impact on combustion efficiency and equipment stability. Then it passes through the second porous medium body 42, which not only effectively increases the evaporation speed of water, but also increases the heat transfer efficiency, ensuring that the water in the coal water slurry can be quickly evaporated and participate in the subsequent combustion reaction. Finally, it passes through the third porous medium body 43, which not only ensures that the fuel in the coal water slurry is gradually and uniformly burned, avoiding the phenomenon of unstable flame caused by too fast burning, but also accurately controls the shape and intensity of the combustion flame, ensuring the completeness and efficiency of combustion, ultimately achieving full combustion of the fuel, improving energy utilization efficiency, and reducing the emission of harmful gases such as carbon monoxide and nitrogen oxides (NOx).

[0056] In addition, the combination of the porous medium stable combustion and cold-hot atomization technology of the coal water slurry burner of the present application enhances the wear resistance and service life of the burner, reduces the frequency and cost of system maintenance, and optimizes the combustion process to more efficiently convert energy and reduce energy consumption, which helps to reduce the operating costs and energy expenditures of enterprises.

[0057] The embodiment of the present application also provides a use method of the above-mentioned coal water slurry burner with porous medium stable combustion and cold-hot atomization technology, which comprises the following steps:

[0058] Step 1, pretreat and mix the coal water slurry to be entered into the coal water slurry channel 14 to ensure its smooth entry into the coal water slurry channel 14.

[0059] The coal water slurry is mixed by the pre-treatment device before entering the burner system. The pre-treatment device can mix the coal powder and water sufficiently, ensuring the uniform combination of the coal powder and water. This can avoid the stratification or unevenness of the coal powder and water, ensuring the flowability and combustion performance of the coal water slurry. The flow of the coal water slurry is adjusted according to the actual combustion demand, and the flow rate of the coal water slurry is generally between 3-7 m / s, to ensure that it smoothly enters the burner system and forms an effective atomization effect.

[0060] Step 2, pre-cooling the coal water slurry in the first mixing chamber 17.

[0061] The coal water slurry enters the first mixing chamber 17 through the coal water slurry channel 14. At this time, the ultra-low temperature gas also enters the first mixing chamber 17 through the ultra-low temperature gas channel 15 at a speed of 15-20 m / s. The ultra-low temperature gas fully contacts the coal water slurry and performs a first-stage pre-cooling effect. Due to the low-temperature characteristics of the ultra-low temperature gas, it can rapidly absorb the heat in the coal water slurry, rapidly cooling the surface or local area of the coal slurry. This cooling process causes the coal water slurry to form a "crispy outside and soft inside" state, with the outer surface becoming brittle and the inside remaining relatively soft. This state is the key to achieving high-efficiency combustion of the coal water slurry after it enters the combustion chamber.

[0062] The viscosity of the coal water slurry after the surface becomes brittle changes as follows:

[0063] Under the action of the ultra-low temperature gas, the surface temperature of the coal water slurry rapidly decreases, and the surface viscosity greatly increases. The apparent viscosity of the coal slurry rapidly increases, forming a brittle state similar to "frozen glue". At this time, the outer layer of the coal water slurry exhibits strong viscosity, while the internal slurry still maintains a low viscosity.

[0064] Step 3, secondary atomization of the coal water slurry by high-temperature steam in the second mixing chamber 18.

[0065] The high-temperature and high-pressure steam enters the second mixing chamber 18 through the high-temperature steam channel 16 at a speed of 30-35 m / s, and performs secondary atomization with the "frozen glue" state coal water slurry in the second mixing chamber 18. The high-temperature and high-pressure steam can rapidly break the "frozen glue" state of the coal water slurry surface, further atomizing and dispersing it into fine particles. The atomization effect in this stage greatly increases the combustion surface area of the coal water slurry, thereby improving the efficiency and stability of combustion.

[0066] Step 4, uniform reaction of the coal water slurry with air in the third mixing chamber 19.

[0067] The water-coal slurry that has been twice atomized by high-temperature and high-pressure steam in the second mixing chamber 18 then enters the third mixing chamber 19. At this time, the particles of the water-coal slurry have been effectively atomized and mixed with the combustion gas. Since the temperature and pressure conditions in the third mixing chamber 19 are suitable, the water-coal slurry can uniformly react with air during this process, further improving the stability and efficiency of combustion.

[0068] Step 5, in the gradient porous medium body assembly 4, the water-coal slurry is subjected to multi-stage filtration and separation.

[0069] The water-coal slurry first passes through the primary filtration and separation of the large-pore octahedral structure of the first porous medium body 41, effectively trapping large-particle substances and impurities, preventing them from entering the subsequent combustion area and reducing the negative impact on combustion efficiency and equipment stability. Smaller particles can pass through and continue to participate in subsequent heat exchange and combustion reactions.

[0070] Then, the water-coal slurry passes through the second porous medium body 42, which adopts a double-layer Voronoi random pore design. This design significantly enhances the evaporation effect of the water-coal slurry by randomly distributing pores in the porous medium. Due to the randomness and irregularity of these pores, they not only effectively increase the evaporation speed of water, but also increase the heat transfer efficiency, ensuring that the water in the water-coal slurry can evaporate quickly and participate in subsequent combustion reactions.

[0071] Finally, the water-coal slurry flows to the third porous medium body 43, which adopts a small-pore tetrahedral structure that can maintain the stability of the combustion process. Specifically, the small-pore design ensures that the fuel in the water-coal slurry burns gradually and uniformly, avoiding the phenomenon of unstable flame caused by too fast combustion. In addition, the small-pore structure can precisely control the shape and intensity of the combustion flame, ensuring complete and efficient combustion, ultimately achieving full combustion of the fuel and improving energy utilization efficiency.

[0072] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A water-coal slurry burner with porous medium stable combustion and coordinated hot and cold atomization, characterized by: It includes a burner head, a neck tube and a porous medium containing tube arranged in sequence along the axial direction; the burner head includes a water-coal slurry tube, an ultra-low temperature gas tube and a high-temperature steam tube which are sequentially arranged from the inside to the outside; the high-temperature steam tube is connected to the porous medium containing tube through the neck tube; the inner cavity of the water-coal slurry tube is a water-coal slurry channel; an ultra-low temperature gas channel is formed between the water-coal slurry tube and the ultra-low temperature gas tube; a high-temperature steam channel is formed between the ultra-low temperature gas tube and the high-temperature steam tube; a first mixing chamber is formed between the outlet end of the water-coal slurry tube and the outlet end of the ultra-low temperature gas tube; a second mixing chamber is formed between the outlet end of the ultra-low temperature gas tube and the outlet end of the high-temperature steam tube; the inner cavity of the neck tube is a third mixing chamber; a gradient porous medium body component is provided in the porous medium containing tube.

2. The porous medium coal-water slurry burner with stable combustion and coordinated cold and hot atomization according to claim 1 is characterized in that: The end surface of the outlet end of the ultra-low temperature gas pipe is higher than the end surface of the outlet end of the water-coal slurry pipe, and lower than the end surface of the outlet end of the high temperature steam pipe.

3. The water-coal slurry burner with porous medium stable combustion and coordinated cold and hot atomization according to claim 1 is characterized in that: The gradient porous medium assembly includes a first porous medium body, a second porous medium body and a third porous medium body arranged in sequence along the axial direction; there are two second porous medium bodies; the first porous medium body is arranged close to the third mixing chamber; the first porous medium body is made of a material with a large-pore octahedron structure that is resistant to high temperature and has high thermal conductivity; the second porous medium body is made of a material with a Voronoi random pore structure that is resistant to high temperature and has high thermal conductivity; and the third porous medium body is made of a material with a small-pore tetradecahedron structure that is resistant to high temperature and has high thermal conductivity.

4. The water-coal slurry burner with porous medium stable combustion and coordinated cold and hot atomization according to claim 3 is characterized in that: The first porous medium, the second porous medium and the third porous medium are all coated with an oleophobic metal oxide coating.

5. The water-coal slurry burner with porous medium stable combustion and coordinated cold and hot atomization according to claim 1 is characterized in that: The length of the first mixing chamber is 1 / 3 of the mixing chamber of a conventional coal slurry burner.

6. The water-coal slurry burner with porous medium stable combustion and coordinated hot and cold atomization according to claim 1 is characterized in that: The ultra-low temperature gas channel is used for the flow of ultra-low temperature gas; the high temperature steam channel is used for the flow of high temperature and high pressure steam; the ultra-low temperature gas can pre-cool and crush the water-coal slurry, weakening the shear resistance of the water-coal slurry; the high temperature and high pressure steam can impact the pre-cooled and brittle water-coal slurry at high speed, improving the atomization characteristics of the water-coal slurry.

7. The water-coal slurry burner with porous medium stable combustion and coordinated cold and hot atomization according to claim 6 is characterized in that: The ultra-low temperature gas is liquid nitrogen evaporated gas or liquid carbon dioxide evaporated gas; the high temperature and high pressure steam is a gas with a temperature greater than 200° C. and a pressure greater than 0.8 MPa.

8. A method for using a water-coal slurry burner with a porous medium for stable combustion and coordinated cold and hot atomization according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Pre-treating and mixing the coal-water slurry to be introduced into the coal-water slurry channel to ensure that it can smoothly enter the coal-water slurry channel; S2. introducing coal water slurry into the coal water slurry channel and introducing ultra-low temperature gas into the ultra-low temperature gas channel, and pre-cooling the coal water slurry entering the coal water slurry channel in the first mixing chamber until the coal water slurry forms a "jelly" state; S3, high-temperature and high-pressure steam is introduced into the high-temperature steam channel, and the water-coal slurry in the "jelly" state is secondary atomized by high-temperature steam in the second mixing chamber to disperse it into fine particles; S4, the water gas atomized particles obtained in step S3 enter the third mixing chamber and react evenly with the air; S5. The water-gas atomized particles obtained in step S4 enter the gradient porous medium assembly for multi-stage filtration and separation.

9. The method of use according to claim 8, characterized in that: The ultra-low temperature gas is liquid nitrogen evaporated gas or liquid carbon dioxide evaporated gas; the high temperature and high pressure steam is a gas with a temperature greater than 200° C. and a pressure greater than 0.8 MPa.

10. The method of use according to claim 8, characterized in that: The flow rate of the ultra-low temperature gas is 15-20 m / s; the flow rate of the high temperature and high pressure steam is 30-35 m / s.

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