An apparatus and method for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal

Abstract

An apparatus and method for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal, belonging to the technical field of solid fuel combustion. The apparatus body includes a separated upper chamber and a lower chamber; the upper end of the upper chamber is connected with a distributor plate, and a capillary tube sequentially passes through the distributor plate, the upper chamber and the partition plate. The upper port of the capillary tube is communicated with the upper outlet of the distributor plate, and the lower port is communicated with the lower chamber; a central powder feeding pipe is arranged in the middle of the distributor plate; the lower chamber is connected with a CO inlet pipe and an H2 inlet pipe, and the upper chamber is connected with a CO2 inlet pipe and an O2 inlet pipe. Flow monitoring and control devices are arranged on each inlet pipe. The present invention successfully introduces high-temperature water vapor into the reaction field to eliminate the influence caused by temperature interference; by fully mixing CO and H2, the water vapor distribution in the post-flame gas is relatively uniform. At the same time, the content of water vapor can be accurately adjusted through calculation, so as to provide a stable and controllable experimental environment for studying the influence of water vapor concentration in the atmosphere on the combustion characteristics of pulverized coal.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid fuel combustion, and particularly relates to an apparatus and method for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal. Background Art

[0002] The Paris Agreement requires limiting the global temperature rise (compared to the pre-industrial period) within 2 °C and further pursuing a lower 1.5 °C. To achieve this goal, new low-carbon combustion technologies have received relatively wide attention, and among them, the oxy-fuel combustion technology is relatively representative. Different from using air as an oxidant in traditional combustion, in the oxy-fuel combustion process, a mixture of pure oxygen and recycled flue gas is introduced into the furnace as an oxidant. Due to the recirculation of flue gas, the water vapor content inside the furnace is much higher than that in the air atmosphere. Generally, the water vapor concentration in the oxy-fuel combustion atmosphere can reach 15 - 30%, and can be up to 40% at most. When changing from air combustion to oxy-fuel combustion, due to the change in the combustion atmosphere, the thermodynamic characteristics, kinetic characteristics, and chemical reaction characteristics during the combustion process will all change accordingly. In order to clarify the influence of the change in the environmental atmosphere on the combustion of pulverized coal particles, it is necessary to conduct in-depth research on the combustion behavior of pulverized coal particles in the furnace under an oxy-fuel environment on a small-scale laboratory-scale mechanism experimental platform, so as to provide support for the operation of a large-scale experimental bench.

[0003] In order to better study the combustion mechanism of single particles or pulverized coal particle flows, generally a relatively small experimental platform is used, and the experimental platform preferably has the characteristics of online sampling and visibility at the same time. In addition, since the amount of pulverized coal used in laboratory research is small and cannot achieve self-sustained combustion, that is, it cannot maintain the high temperature of the furnace by its own combustion heat production. Therefore, external heating or artificial creation of a high-temperature atmosphere is required, and in order to be closer to the actual furnace atmosphere, there are relatively high requirements for the temperature of the atmosphere and the component concentration in the atmosphere. Currently, the widely used laboratory-scale burners mainly include thermogravimetric analyzers, drop tube furnaces, and flat-flame burners. Among them, as described above, since the flat-flame burner has the characteristics of online sampling and visibility at the same time, it is widely used. Here, the flat-flame burner refers to using a specific fuel gas (such as CO, etc.), an oxidant (O2), and a diluent gas (such as N2 / CO2, etc.) to generate high-temperature post-combustion gas through combustion, so as to provide a high-temperature environment for the combustion of pulverized coal. By precisely controlling the flow rates of the fuel, oxidant, and diluent of the burner, the temperature and oxygen concentration of the post-combustion gas can be precisely adjusted and controlled, so as to realize the study of the combustion behavior of pulverized coal under different temperature and oxygen concentration conditions. Although the flat-flame burner has good adjustment performance, currently the main research work mainly focuses on studying the influence of environmental temperature, oxygen concentration in the atmosphere, and the switching between conventional combustion / oxy-fuel combustion on the combustion characteristics of pulverized coal, and there is still a lack of effective methods for using it to study the influence of water vapor content.

[0004] In order to simulate the water vapor content in the actual atmosphere on the laboratory experimental platform, most of the existing laboratory research work directly uses a steam generator to generate water vapor, and through a certain preheating device, the temperature of the water vapor is raised to about 200 °C, and then it is transported to the high-temperature field through a pipeline. This method is simple, feasible and easy to operate, so it is widely used in laboratory thermogravimetric analyzers, drop tube furnaces and flat-flame burners. It should be noted that by directly introducing water vapor to add the water vapor content in the atmosphere, on the one hand, the temperature of the introduced water vapor (about 200 °C) is mostly several hundred degrees lower than the experimental temperature condition set in the experiment (such as 1200 °C), which will inevitably cause a change in the originally set experimental temperature field; at the same time, the newly introduced water vapor is unevenly distributed in the high-temperature field, thus bringing great uncertainty to the experimental results. On the other hand, for a flat-flame burner, introducing additional water vapor without reducing the originally set component conditions will cause a change in the partial pressure of each component in the atmosphere where the pulverized coal particles are located. Since factors such as oxygen concentration and carbon dioxide concentration are also important factors affecting the combustion behavior of pulverized coal, this will also bring great uncertainty to the experiment, making the experimental results lack credibility. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a device and method for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal, with reasonable structural design, which can provide a stable and controllable experimental environment for studying the influence of water vapor concentration in the atmosphere on the combustion characteristics of pulverized coal.

[0006] The present invention is realized through the following technical solutions:

[0007] The present invention discloses a device for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal, including a device body. The inside of the device body includes an upper chamber and a lower chamber separated by a partition; the upper end of the upper chamber is connected with a wind distribution plate, and a number of capillary tubes sequentially pass through the wind distribution plate, the upper chamber and the partition. The upper port of the capillary tube is communicated with the upper outlet of the wind distribution plate, and the lower port of the capillary tube is communicated with the lower chamber; a central powder feeding tube is arranged in the middle of the wind distribution plate, and the central powder feeding tube is connected with a pulverized coal feeding system; the lower chamber is connected with a CO inlet pipe and an H2 inlet pipe, and the upper chamber is connected with a CO2 inlet pipe and an O2 inlet pipe. Flow monitoring and control devices are provided on the CO inlet pipe, H2 inlet pipe, CO2 inlet pipe and O2 inlet pipe.

[0008] Preferably, the partition is a silica gel partition.

[0009] Preferably, the wind distribution plate is a honeycomb wind distribution plate.

[0010] Preferably, the upper port of the capillary tube is higher than the upper plane of the wind distribution plate.

[0011] Preferably, a plurality of capillary tubes are evenly distributed on the air distribution plate.

[0012] Preferably, the flow rate monitoring and control device includes a mass flow meter and a regulating valve.

[0013] Preferably, the CO inlet pipe and the H2 inlet pipe are connected to a mixing chamber, and the outlet of the mixing chamber is connected to the lower chamber through a pipeline.

[0014] Further preferably, the inner wall of the mixing chamber is a continuous smooth curved surface.

[0015] Preferably, the inner walls of the upper chamber and the lower chamber are continuous smooth curved surfaces.

[0016] The method for research using the device for researching the influence of water vapor concentration on pulverized coal combustion characteristics disclosed by the present invention includes:

[0017] After setting the relevant parameters of the initial working condition, adjust the flow rates of CO, H2, O2, and CO2 through the flow rate monitoring and control device. CO and H2 enter the lower chamber, O2 and CO2 enter the upper chamber. The CO and H2 in the lower chamber are transported to the upper port through the capillary tubes, and after being ignited, react with the O2 and CO2 flowing out from the outlet above the air distribution plate to form diffused small flame units. A plurality of small flame units form a planar flame, and then a post-flame high-temperature field is formed; the pulverized coal enters the post-flame high-temperature field through the carrier gas from the central coal feeding pipe for combustion;

[0018] After completing the initial working condition experiment, by adjusting the flow rates of CO, H2, O2, and CO2, under the condition of ensuring that the temperature, the oxygen concentration of the post-flame gas, and the flow rate of the post-flame gas remain unchanged, realize the atmosphere conversion of different post-flame gas water vapor concentrations, and conduct research on the influence of water vapor concentration on the combustion characteristics of pulverized coal particles; specifically, it is realized through the following formulas:

[0019] The chemical reaction formula occurring in the device is as follows:

[0020] aCO + bH2 + cO2 + dCO2 → eCO2 + fH2O + gO2

[0021] Obtained from the element conservation:

[0022] a + d = e

[0023] a + 2c + 2d = 2e + f + 2g

[0024] 2b = 2f

[0025] The temperature control equation is:

[0026] a×h(CO, 298K) + b×h(H2, 298K) + c×h(O2, 298K) + d×h(CO2, 298K)

[0027] = e×h(CO2, T) + f×h(H2O, T) + g×h(O2, T)

[0028] Post-flame gas velocity control equation:

[0029]

[0030] Post-flame gas oxygen concentration control equation:

[0031]

[0032] Post-flame gas water vapor concentration control equation:

[0033]

[0034] where h is the absolute enthalpy of the gas at this temperature; v gas is the velocity of the post-flame gas; R is the universal gas constant; T is the post-flame gas temperature; A is the cross-sectional area of the burner; is the mole fraction of oxygen in the post-flame gas; is the mole fraction of water vapor in the post-flame gas.

[0035] Compared with the prior art, the present invention has the following beneficial technical effects:

[0036] An apparatus for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal, which is based on a laboratory-scale planar flame burner. By reasonably proportioning the fuel gas, the water vapor content in the post-reaction gas can be reasonably adjusted. The introduction of water vapor is achieved through the combustion of H-containing fuels, such as using H2 as the H-containing fuel. In order to be able to adjust the water vapor content, CO without H is simultaneously used as the fuel gas for fuel proportioning; O2 is used as the oxidant, plus the diluent CO2, to simulate the relatively high carbon dioxide concentration in the ambient atmosphere under oxygen-rich conditions. Since H2 has a wide explosion limit and is extremely prone to flashback, a relatively safe diffusion flame method is adopted in this experimental system. At the intake end of the apparatus body, the fuel and the oxidant are separated into two different chambers, and a partition is made between the two chambers. The fuel and the oxidant enter the lower chamber and the upper chamber of the apparatus body respectively. The fuel in the lower chamber is transported to the outlet of the apparatus body through a capillary tube and undergoes an oxidation combustion reaction with the oxidant in the upper chamber at the outlet, generating high-temperature post-reaction gas. The pulverized coal then enters the high-temperature atmosphere environment generated by the above reaction through the central powder feeding tube, and then undergoes stages such as pyrolysis, ignition, volatile combustion, and coke combustion. Since the carrier gas for transporting the pulverized coal generally has a small flow rate, the influence of this part of the carrier gas on the temperature field and the component field can be roughly ignored. Therefore, under such conditions, the pulverized coal particles can be considered to be instantaneously exposed to a high-temperature multi-component field, and their combustion characteristics depend on the characteristics of the surrounding flow field. In the experimental design, the water vapor content in the post-reaction gas is precisely controlled by controlling the gas flow rate. The apparatus of the present invention can successfully introduce high-temperature water vapor into the reaction field and eliminate the influence caused by temperature interference. Moreover, by fully mixing the fuel gas CO and H2, the water vapor distribution in the post-reaction gas can be made more uniform. At the same time, the water vapor content can be precisely adjusted through calculation, thereby providing a stable and controllable experimental environment for studying the influence of water vapor concentration in the atmosphere on the combustion characteristics of pulverized coal.

[0037] Further, the partition plate is made of a silica gel partition plate, which has good corrosion resistance.

[0038] Further, the air distribution plate is a honeycomb air distribution plate, and the air distribution is uniform.

[0039] Further, the upper port of the capillary tube is higher than the upper plane of the air distribution plate, which is beneficial to the full diffusion and mixing of the oxidant and the diluent.

[0040] Further, a plurality of capillary tubes are evenly distributed on the air distribution plate, so that the mixing and combustion of the gas are uniform.

[0041] Further, before entering the burner, the fuel gases CO and H2 first enter the mixing chamber for full mixing to ensure uniform distribution of components in the high-temperature field after combustion.

[0042] Furthermore, the inner wall of the mixing chamber is a continuous smooth curved surface, which improves the mixing effect and avoids sedimentation.

[0043] Furthermore, the inner walls of the upper chamber and the lower chamber are continuous smooth surfaces, enabling the two entering gases to be evenly mixed and preventing accumulation at dead ends.

[0044] The method for conducting research using the device for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal disclosed in the present invention is simple to operate and can precisely adjust the content of water vapor, thereby providing a stable and controllable experimental environment for studying the influence of water vapor concentration in the atmosphere on the combustion characteristics of pulverized coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic diagram of the overall structure of the device for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal according to the present invention;

[0046] Figure 2 is a schematic diagram of the experimental method flow according to the present invention.

[0047] In the figure: 1 - Flow monitoring and control device, 2 - Mixing chamber, 3 - Lower chamber, 4 - Capillary tube, 5 - Upper chamber, 6 - Air distribution plate, 7 - Plane flame, 8 - Central coal powder feeding tube, 9 - High-temperature post-flame field. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The following further describes the present invention in detail with reference to the drawings and specific embodiments. The content is an explanation of the present invention rather than a limitation:

[0049] As Figure 1 , the device for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal according to the present invention includes a device body. Inside the device body, there are an upper chamber 5 and a lower chamber 3 separated by a partition. The partition is preferably a silica gel partition; the upper end of the upper chamber 5 is connected to an air distribution plate 6, and the air distribution plate 6 is preferably a honeycomb air distribution plate; a number of capillary tubes 4 sequentially pass through the air distribution plate 6, the upper chamber 5, and the partition. The upper port of the capillary tube 4 communicates with the upper outlet of the air distribution plate 6; preferably, a number of capillary tubes 4 are evenly distributed on the air distribution plate 6; preferably, the upper port of the capillary tube 4 is higher than the upper plane of the air distribution plate 6; the lower port of the capillary tube 4 communicates with the lower chamber 3; a central coal powder feeding tube 8 is provided in the middle of the air distribution plate 6, and the central coal powder feeding tube 8 is connected to a coal powder feeding system; the lower chamber 3 is connected to a CO inlet pipe and an H2 inlet pipe, and the upper chamber 5 is connected to a CO2 inlet pipe and an O2 inlet pipe. Flow monitoring and control devices 1 are provided on the CO inlet pipe, the H2 inlet pipe, the CO2 inlet pipe, and the O2 inlet pipe.

[0050] The flow monitoring and control device 1 includes a mass flow meter and a regulating valve.

[0051] In a preferred embodiment of the present invention, the CO inlet pipe and the H2 inlet pipe are connected to a mixing chamber 2, and the outlet of the mixing chamber 2 is connected to a lower chamber 3 through a pipeline; the inner wall of the mixing chamber 2 is a continuous smooth surface. At the same time, the inner walls of the upper chamber 5 and the lower chamber 3 are also continuous smooth surfaces.

[0052] The above device is based on a laboratory-scale planar flame burner. By reasonably matching the fuel gas, the reasonable adjustment of the water vapor content in the post-reaction flame gas is achieved. In the present invention, the introduction of water vapor is generated by the combustion of H-containing fuel. For example, H2 is used as the H-containing fuel. In order to adjust the water vapor content, CO without H is used as the fuel gas for fuel ratio at the same time; O2 is used as the oxidant; CO2 (N2 can also be used) is used as the diluent gas to simulate the higher carbon dioxide concentration in the ambient atmosphere under the oxygen-rich condition. Before entering the burner, the fuel gases CO and H2 first enter the mixing chamber for sufficient mixing to ensure uniform distribution of components in the high-temperature field after combustion. Since H2 has a wide explosion limit and is extremely prone to flashback, a relatively safe diffusion flame method is adopted in this experimental system. At the inlet end of the burner, the fuel and the oxidant are separated into two different chambers, and the two chambers are separated by a metal or silica gel gasket. The fuel and the oxidant enter the lower chamber and the upper chamber of the burner respectively. The fuel in the lower chamber is transported to the burner outlet through a capillary tube and undergoes an oxidation combustion reaction with the oxidant in the upper chamber at the outlet to generate high-temperature post-flame gas. The pulverized coal is carried by a small amount of carrier gas (CO2) through the central tube in the center of the burner into the high-temperature atmosphere environment generated by the above reaction, and then undergoes pyrolysis, ignition, volatile combustion, coke combustion and other stages. Since the carrier gas flow rate is small, the influence of this part of the carrier gas on the temperature field and the component field can be roughly ignored. Therefore, under such conditions, the pulverized coal particles can be considered to be instantaneously exposed to the high-temperature multi-component field, and their combustion characteristics depend on the characteristics of the surrounding flow field. In the experimental design, the water vapor content in the post-flame gas is precisely controlled by controlling the gas flow rate. Specifically as follows. The chemical reaction equation for CO and H2 under the above conditions is

[0053] aCO + bH2 + cO2 + dCO2 → eCO2 + fH2O + gO2. (1)

[0054] In the experiment, an excessive amount of oxidant O2 is used. Therefore, there is still an excessive amount of oxygen in the high-temperature post-flame gas after the full combustion of CO and H2, which has a good similarity to the atmosphere with a certain concentration of oxygen in the high-temperature flue gas inside the actual furnace. In order to study the influence of water vapor by the method of controlling variables, it is necessary to keep key parameters such as temperature and oxygen concentration consistent. The control equations used in the experimental design are as follows:

[0055] Element conservation:

[0056] a + d = e, (2)

[0057] a + 2c + 2d = 2e + f + 2g, (3)

[0058] 2b = 2f. (4)

[0059] The temperature control equation is:

[0060] a×h(CO, 298K) + b×h(H2, 298K) + c×h(O2, 298K) + d×h(CO2, 298K) = e×h(CO2, T) + f×h(H2O, T) + g×h(O2, T). (5)

[0061] The post - flame gas velocity control equation:

[0062]

[0063] The post - flame gas oxygen concentration control equation:

[0064]

[0065] The post - flame gas water vapor concentration control equation:

[0066]

[0067] In the above equations, h is the absolute enthalpy of the gas at this temperature; v gas is the velocity of the post - flame gas; R is the universal gas constant; T is the post - flame gas temperature; A is the cross - sectional area of the burner; is the mole fraction of oxygen in the post - flame gas; is the molar fraction of water vapor in the post-flame gas. As described above, for a given operating condition, there can be 7 governing equations ((2)-(8)), and according to the chemical reaction equations, for a specific reaction condition, there are a total of 7 independent variables (a-g). Therefore, this is a statically determinate system of equations. By solving the above equations, the flow rates of fuel, oxidizer, and diluent required for a given operating condition can be obtained, and by adjusting the flow rates of H2 and CO, the adjustment of water vapor concentration can also be achieved under the condition of ensuring the same temperature, oxygen concentration, and post-flame gas velocity. Exemplarily, for a flat-flame burner with an outlet cross-sectional diameter of 6 cm, setting its post-reaction flame gas velocity to 1.5 m / s, if it is required to change the water vapor concentration in the atmosphere and study its influence on the pulverized coal combustion characteristics under the condition of an ambient temperature of 1500 K and an oxygen concentration of 0.2 in the atmosphere. By solving equations (2)-(8), the gas flow rates under typical operating conditions are shown in Table 1. It can be seen that by adjusting the proportion of fuel gas, the controllable change of water vapor concentration in the target operating condition can be achieved. It should be noted that due to temperature limitations, at a specific temperature, there is a corresponding upper limit value for the water vapor content. For example, under the 1500 K operating condition, the upper limit value of the water vapor concentration in the atmosphere is approximately 0.225; under the 2000 K operating condition, the upper limit value of the water vapor concentration is approximately 0.325.

[0068] Table 1. Gas distribution schemes with different water vapor concentrations under the 1500K-0.2O2 condition

[0069]

[0070] such as Figure 2In the experiment, the temperature, oxygen concentration, post-flame gas velocity and water vapor concentration of the selected working condition are first determined. By solving equations (2)-(8), the required flow rates of fuel gas CO, H2, oxidant O2 and diluent CO2 under the selected working condition are determined. By adjusting the regulating valve, the flow rate of each gas entering the burner is accurately controlled. CO and H2 are controlled by the flow meter and enter the mixing chamber 2. After being fully mixed in the mixing chamber 2, they enter the lower chamber 3 of the burner. The oxidant and diluent gas enter the upper chamber 5 of the burner after mixing. The two chambers are separated by a silica gel partition. The fuel in the lower chamber 3 is transported to the burner outlet through the capillary 4. After the oxidant and diluent gas in the upper chamber 5 pass through the honeycomb air distribution plate, they are ignited by an external fire source and react with the fuel gas at the outlet of the capillary 4 to form a number of diffusion small flame units, and a number of diffusion small flame units form a plane flame 7. Because the capillary is thin enough and the distribution is dense enough, the components of the post-flame gas field of the reaction are relatively uniform. The main components in the post-flame gas field are CO2, O2 and H2O. So far, the post-flame high temperature field 9 for studying the combustion characteristics of pulverized coal has been formed. Next, the pulverized coal particles are carried by a small amount of carrier gas (~0.5L / min) and enter the post-flame high temperature field 9 through the central powder feeding pipe 8. When the pulverized coal enters the post-flame high temperature field 9, pyrolysis, ignition, volatile combustion and coke combustion occur successively.

[0071] After completing an experiment under one working condition, the concentration of water vapor is adjusted while ensuring that the temperature, oxygen concentration, and post-flame gas flow rate remain unchanged, and the flow rates of fuel gas, oxidant, and diluent gas under the new working condition are recalculated using equations (2)-(8). The flow meter is adjusted so that the actual flow rate is the same as the calculated working condition, thus completing the atmosphere conversion with different water vapor concentrations. Through this adjustment method, the effect of water vapor on the combustion characteristics of coal powder particles can be studied within a larger temperature variation range (~600K-2000K) and a larger water vapor adjustment range (0%-32.5%). The water vapor distribution in the high temperature field generated in this way is relatively uniform, and the temperature is consistent with the set working condition, thereby reducing the uncertainty error caused by the additional introduction of water vapor.

[0072] It should be noted that the above is only a part of the implementation method of the present invention. The equivalent changes made to the system described in the present invention are all included in the protection scope of the present invention. For example, in the selection of hydrogen-containing fuel, H2 is selected in the above example, and other hydrogen-containing fuels are all included in the scope of this patent. Technicians in the technical field to which the present invention belongs can make similar substitutions for the specific examples described, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they are all within the protection scope of the present invention.

Claims

1. An apparatus for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal, characterized in that, It includes a device body, and inside the device body, there are an upper chamber (5) and a lower chamber (3) separated by a partition; the upper end of the upper chamber (5) is connected with a air distribution plate (6), and a number of capillary tubes (4) sequentially pass through the air distribution plate (6), the upper chamber (5) and the partition. The upper port of the capillary tube (4) is communicated with the upper outlet above the air distribution plate (6), and the lower port of the capillary tube (4) is communicated with the lower chamber (3); a central coal powder feeding pipe (8) is arranged in the middle of the air distribution plate (6), and the central coal powder feeding pipe (8) is connected with a coal powder feeding system; the lower chamber (3) is connected with a CO inlet pipe and a H2 inlet pipe, the upper chamber (5) is connected with a CO2 inlet pipe and an O2 inlet pipe, and flow rate monitoring and control devices (1) are arranged on the CO inlet pipe, the H2 inlet pipe, the CO2 inlet pipe and the O2 inlet pipe; The upper port of the capillary tube (4) is higher than the upper plane of the air distribution plate (6); A number of capillary tubes (4) are evenly distributed on the air distribution plate (6); The CO inlet pipe and the H2 inlet pipe are connected with a mixing chamber (2), and the outlet of the mixing chamber (2) is connected with the lower chamber (3) through a pipeline; Fuel gases CO and H2 first enter the mixing chamber for full mixing; The inner wall of the mixing chamber (2) is a continuous smooth curved surface; The inner walls of the upper chamber (5) and the lower chamber (3) are continuous smooth curved surfaces.

2. The apparatus for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal according to claim 1, characterized in that, The partition is a silica gel partition.

3. The apparatus for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal according to claim 1, characterized in that, The air distribution plate (6) is a honeycomb air distribution plate.

4. The apparatus for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal according to claim 1, characterized in that, The flow rate monitoring and control device (1) includes a mass flowmeter and a regulating valve.

5. A method for studying using the apparatus for studying the influence of water vapor concentration on the combustion characteristics of pulverized coal according to any one of claims 1 to 4, characterized in that, It includes: After setting the relevant parameters of the initial working condition, the flow rates of CO, H2, O2 and CO2 are adjusted through the flow rate monitoring and control device (1). CO and H2 enter the lower chamber (3), O2 and CO2 enter the upper chamber (5). The CO and H2 in the lower chamber (3) are transported to the upper port through the capillary tubes (4), and after being ignited, they react with the O2 and CO2 flowing out from the upper outlet of the air distribution plate (6) to form diffused small flame units. A number of small flame units form a planar flame (7), and then a post-flame high-temperature field (9) is formed; the coal powder enters the post-flame high-temperature field (9) for combustion through the carrier gas from the central coal powder feeding pipe (8); After completing the initial working condition experiment, by adjusting the flow rates of CO, H2, O2 and CO2, under the condition of keeping the temperature, the oxygen concentration of the post-flame gas and the flow rate of the post-flame gas unchanged, the atmosphere conversion of different water vapor concentrations of the post-flame gas is realized, and the influence of the water vapor concentration on the combustion characteristics of coal powder particles is studied; specifically, it is realized through the following formulas: The chemical reaction formulas occurring in the device are as follows: a CO+ b H2+ c O2+ d CO2→ e CO2+ f H2O+ g O2 Obtained from the element conservation: a + d = e a +2 c +2 d = 2 e + f +2 g 2 b = 2 f The temperature control equation is: The post-flame gas velocity control equation: The post-flame gas oxygen concentration control equation: The post-flame gas water vapor concentration control equation: wherein, is the absolute enthalpy of the gas at this temperature; is the velocity of the post-flame gas; R is the universal gas constant; is the post-flame gas temperature; is the burner cross-sectional area; is the mole fraction of oxygen in the post-flame gas; is the mole fraction of water vapor in the post-flame gas.

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