A co2-rich flue gas injection insulated combustion furnace for oxy-combustion carbon capture

Abstract

The application provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion and carbon capture, which is characterized by the following steps: setting a furnace wall outer shell and a furnace wall inner shell, and opening a hole in the furnace wall inner shell to form a combustion furnace inner cavity and a combustion furnace interlayer which are connected through the hole opened in the furnace wall inner shell; extracting a part of combustion tail gas as a backflow gas into the combustion furnace interlayer and injecting the backflow gas into the combustion furnace inner cavity through the hole opened in the furnace wall inner shell to form an air film heat insulation layer at the furnace wall inner shell of the combustion furnace inner cavity, thereby reducing the heating effect of the oxygen-enriched combustion reaction in the combustion furnace inner cavity on the furnace wall; meanwhile, the carbon dioxide concentration in the combustion tail gas is continuously increased after repeated backflow of the combustion tail gas, thereby realizing enrichment of carbon dioxide in the flue gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of carbon dioxide tail gas recovery and oxy-combustion technology, and particularly relates to a CO2-rich flue gas injection heat insulation combustion furnace for oxy-combustion carbon capture. BACKGROUND

[0002] At present, the environmental protection demand such as energy saving and emission reduction in the fields of glass industry, metallurgical industry and thermal energy engineering increases, the oxy-combustion technology significantly reduces the combustion air amount and flue gas generation amount by using high-purity oxygen instead of combustion air, and has significant energy saving effect. Among them, the purification separation and recovery treatment of carbon dioxide tail gas have important social benefits. The development and application of carbon dioxide tail gas recovery technology not only can effectively reduce the greenhouse gas emission, but also provides convenience for CO2 capture and compression.

[0003] At present, the oxy-combustion furnace significantly improves the combustion efficiency and thermal efficiency by using pure oxygen or high-concentration oxygen as oxidant, and reduces the pollutant emission, but at the same time, it also brings higher initial investment and operation cost. Most of the oxy-combustion furnaces have higher requirements for the high-temperature resistance and safety of the equipment due to the high-temperature and high-concentration oxygen environment, and have higher maintenance cost.

[0004] In summary, it is necessary to develop a CO2-rich flue gas injection heat insulation combustion furnace for oxy-combustion carbon capture. SUMMARY

[0005] In view of the problems in the prior art, the present application provides a CO2-rich flue gas injection heat insulation combustion furnace for oxy-combustion carbon capture, a furnace wall inner shell is arranged in a furnace wall outer shell, and a hole is formed in the furnace wall inner shell, so that a combustion furnace inner cavity and a combustion furnace interlayer are connected through the hole formed in the furnace wall inner shell; a part of the combustion tail gas is extracted as a backflow gas into the combustion furnace interlayer and injected into the combustion furnace inner cavity through the hole formed in the furnace wall inner shell, so that a gas film temperature insulation layer is formed at the furnace wall inner shell of the combustion furnace inner cavity, the heating effect of the furnace wall caused by the oxy-combustion reaction in the combustion furnace inner cavity is reduced, and at the same time, the carbon dioxide concentration in the combustion tail gas is continuously increased after repeated backflow, so that the carbon dioxide in the flue gas is enriched.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] The present application aims to provide a CO2-rich flue gas injection heat insulation combustion furnace for oxy-combustion carbon capture, which comprises a furnace wall outer shell, a furnace wall inner shell is arranged in the furnace wall outer shell, a combustion furnace inner cavity is formed in the furnace wall inner shell, and a combustion furnace interlayer is formed between the furnace wall inner shell and the furnace wall outer shell; a hole is formed in the four surrounding sides of the furnace wall inner shell, and the combustion furnace inner cavity and the combustion furnace interlayer are connected through the hole formed in the furnace wall inner shell;

[0008] The bottom of the furnace wall shell is provided with a mixed feed inlet for feeding the mixture of fuel and oxygen-rich gas into the inner cavity of the combustion furnace; the top of the furnace wall shell is provided with a combustion tail gas discharge port connected with the inlet of the waste heat recovery device for discharging the combustion tail gas in the inner cavity of the combustion furnace and introducing it into the waste heat recovery device;

[0009] The bottom of the furnace wall shell is also provided with a backflow gas inlet; the outlet of the waste heat recovery device is connected with a flow control device, and the combustion tail gas after waste heat recovery is divided into two parts, the first part is used as product gas for oxygen-enriched combustion carbon capture, and the second part is used as backflow gas returning to the backflow gas inlet and entering the combustion furnace interlayer and being injected into the inner cavity of the combustion furnace through the holes in the furnace wall inner shell.

[0010] It should be noted that the pipeline corresponding to the mixed feed inlet extends into the inner cavity of the combustion furnace and is welded to the furnace wall shell and the furnace wall inner shell respectively to ensure air tightness; similarly, the pipeline corresponding to the combustion tail gas discharge port extends into the inner cavity of the combustion furnace and is welded to the furnace wall shell and the furnace wall inner shell respectively to ensure air tightness. The waste heat recovery device can fully utilize the heat of the combustion tail gas, and the cooled tail gas obtained is divided into two parts by the flow control device, the first part is used as product gas for oxygen-enriched combustion carbon capture, and the second part is used as backflow gas returning to the backflow gas inlet and entering the combustion furnace interlayer and being injected into the inner cavity of the combustion furnace through the holes in the furnace wall inner shell.

[0011] The application provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, a part of the combustion tail gas is extracted as backflow gas into the combustion furnace interlayer and injected into the inner cavity of the combustion furnace through the holes in the furnace wall inner shell, the backflow gas flows along the furnace wall in the inner cavity of the combustion furnace and forms a cyclone as a gas film temperature insulation layer, reducing the heating effect of the oxygen-enriched combustion reaction in the inner cavity of the combustion furnace on the furnace wall, at the same time, the concentration of carbon dioxide in the combustion tail gas is continuously increased after repeated backflow, realizing the enrichment of carbon dioxide in the product gas.

[0012] The application provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, which reduces the operating temperature of the combustion furnace equipment, reduces the requirement for high-temperature resistance of the equipment material, improves the durability of the equipment, and also increases the CO2 content in the combustion tail gas; the maintenance cost of the equipment is low, and the CO2 recovery concentration is high.

[0013] The application provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, which can establish an injection heat insulation layer in the combustion furnace, thereby reducing the contact temperature of the furnace body material, and the produced combustion tail gas is rich in carbon dioxide gas, and the product carbon dioxide has higher purity and is easier to recover; the equipment has high production economy, low maintenance cost, high CO2 recovery concentration, and can effectively reduce the investment and operation cost of a production enterprise.

[0014] As a preferred technical solution of the application, the hole is inclined upward along the outward-to-inward direction, so that the backflow gas entering the combustion furnace interlayer is injected into the combustion furnace inner cavity in an upwardly inclined direction.

[0015] As a preferred technical solution of the application, the central axis of the hole is inclined upward at an angle of 30-60 degrees with respect to the horizontal plane, for example, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees or 60 degrees, etc.

[0016] As a preferred technical solution of the application, the radial deviation angle of the central axis of the hole is 60-85 degrees in the radial direction, for example, 60 degrees, 63 degrees, 65 degrees, 68 degrees, 70 degrees, 72 degrees, 75 degrees, 77 degrees, 80 degrees, 83 degrees or 85 degrees, etc., so that the backflow gas entering the combustion furnace interlayer forms a rotational flow.

[0017] As a preferred technical solution of the application, the hole type of the hole is a tapered hole, the hole diameter of the tapered hole decreases along the outward-to-inward direction, the large end diameter of the tapered hole is 3-20 mm, for example, 3 mm, 5 mm, 7 mm, 10 mm, 13 mm, 15 mm, 18 mm or 20 mm, etc., and the small end diameter of the tapered hole is 2-15 mm, for example, 2 mm, 5 mm, 7 mm, 10 mm, 13 mm or 15 mm, etc.

[0018] As a preferred technical solution of the application, the arrangement mode of the holes is arranged in a regular triangle or a square, and the center distance between adjacent two holes is 1.5-10 times the diameter of the hole, for example, 1.5 times, 3 times, 4.5 times, 6 times, 7.5 times, 9 times or 10 times, etc. It should be noted that when the hole type of the hole is a tapered hole, the center distance between adjacent two holes is 1.5-10 times the large end diameter of the tapered hole.

[0019] As a preferred technical solution of the application, on the outside of the furnace wall shell, the mixed feed inlet is formed by the fuel feed inlet and the oxygen-enriched gas inlet, the fuel feed inlet is used for feeding fuel, and the oxygen-enriched gas inlet is used for feeding oxygen-enriched gas. For example, the fuel feed inlet is used for filling solid combustion, and the oxygen-enriched gas inlet is used for connecting the oxygen-enriched gas provided by the upstream.

[0020] As a preferred technical scheme of the present application, a heat exchanger is arranged at the top of the inner cavity of the combustion furnace, for exchanging heat between the combustion tail gas and the fluid flowing inside the heat exchanger, and recovering part of the heat of the combustion tail gas.

[0021] It should be noted that the fluid flows inside the heat exchanger, and the flowing fluid can exchange heat with the combustion tail gas, so as to recover the combustion heat, and the temperature of the combustion tail gas will decrease after flowing through the heat exchanger.

[0022] As a preferred technical scheme of the present application, the flow splitting controller comprises a flow splitting control valve.

[0023] As a preferred technical scheme of the present application, an air blower is arranged on the pipeline through which the backflow gas returns to the combustion furnace interlayer.

[0024] As a preferred technical scheme of the present application, a buffer tank is arranged at the outlet of the air blower.

[0025] It should be noted that the air blower can pressurize the backflow gas, and the buffer tank can stabilize the pressure of the pressurized backflow gas.

[0026] Compared with the prior art, the present application has at least the following beneficial effects:

[0027] The present application provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, a part of the combustion tail gas is extracted as backflow gas into the combustion furnace interlayer and is injected into the inner cavity of the combustion furnace through the holes opened in the inner shell of the furnace wall, the backflow gas flows along the furnace wall in the inner cavity of the combustion furnace, forms a cyclone, and serves as a gas film heat insulation layer, thereby reducing the heating effect of the oxygen-enriched combustion reaction in the inner cavity of the combustion furnace on the furnace wall, and meanwhile, the concentration of carbon dioxide in the combustion tail gas is continuously increased after repeated backflow, thereby realizing the enrichment of carbon dioxide in the product gas. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic view of the CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture according to Embodiment 1 of the present application;

[0029] Figure 2 is a schematic view of the radial deflection angle of the holes according to Embodiment 1 of the present application;

[0030] In the figure: 1-furnace wall outer shell; 2-furnace wall inner shell; 3-inner cavity of the combustion furnace; 4-combustion furnace interlayer; 5-hole; 6-heat exchanger; 7-combustion tail gas discharge port; 8-waste heat recovery device; 9-flow splitting controller; 10-air blower; 11-buffer tank; 12-backflow gas inlet; 13-mixed feed inlet; 14-fuel feed inlet; 15-oxygen-enriched gas inlet. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0033] Example 1

[0034] This embodiment provides a CO2-rich flue gas injection insulated combustion furnace for carbon capture during oxygen-rich combustion, such as... Figure 1 As shown, the furnace includes an outer furnace wall 1, an inner furnace wall 2 is disposed inside the outer furnace wall 1, a combustion furnace cavity 3 is formed inside the inner furnace wall 2, and a combustion furnace interlayer 4 is formed between the inner furnace wall 2 and the outer furnace wall 1; holes 5 are opened on the four sides of the inner furnace wall 2, and the combustion furnace cavity 3 and the combustion furnace interlayer 4 are connected through the holes 5 opened in the inner furnace wall 2.

[0035] The bottom of the furnace wall shell 1 is provided with a mixing inlet 13 for introducing the mixture of fuel and oxygen-enriched gas into the combustion furnace cavity 3; the top of the furnace wall shell 1 is provided with a combustion exhaust gas outlet 7, which is connected to the inlet of the waste heat recovery unit 8 for discharging the combustion exhaust gas from the combustion furnace cavity and introducing it into the waste heat recovery unit 8.

[0036] The bottom of the furnace wall shell 1 is also provided with a return gas inlet 12; the outlet of the waste heat recovery unit 8 is connected to the diversion controller 9, which divides the combustion exhaust gas after waste heat recovery into two parts. The first part is used as product gas for oxygen-enriched combustion and carbon capture, and the second part is returned to the return gas inlet 12 as return gas, enters the combustion furnace jacket 4, and is injected into the combustion furnace cavity 3 through the holes 5 opened in the furnace wall shell 2.

[0037] Specifically, the orifice 5 is inclined upwards along the direction from the outside to the inside, so that the return gas entering the combustion furnace jacket 4 is injected into the combustion furnace cavity 3 in an oblique upward direction; the central axis of the orifice 5 is inclined upwards at an angle of 45 degrees relative to the horizontal plane; from a top-down angle, through Figure 2 The diagram schematically illustrates the radial deflection angle of the hole, specifically the radial deflection angle of the central axis of the hole 5 along the radial direction (i.e., Figure 2 The angle θ is 70 degrees, which causes the return gas entering the combustion furnace jacket 4 to form a swirling flow; the hole is a conical hole, and the diameter of the conical hole decreases from the outside to the inside, with the large end diameter of the conical hole being 15 mm and the small end diameter being 8 mm; the holes are arranged in an equilateral triangle, and the center distance between two adjacent holes is 3 times the large end diameter of the conical hole;

[0038] On the outside of the furnace wall shell 1, the mixed feed port 13 is formed by the fuel feed port 14 and the oxygen-enriched gas inlet port 15, the fuel feed port 14 is used for feeding fuel, and the oxygen-enriched gas inlet port 15 is used for feeding oxygen-enriched gas;

[0039] A heat exchanger 6 is arranged at the top of the combustion furnace cavity 3, which is used for heat exchange between the combustion tail gas and the fluid flowing in the heat exchanger 6, and part of the heat of the combustion tail gas is recovered;

[0040] The flow control device 9 includes a flow control valve; on the pipeline returning the backflow gas to the combustion furnace interlayer 4, a blower 10 is arranged, and a buffer tank 11 is arranged at the outlet of the blower 10.

[0041] Embodiment 2

[0042] The embodiment provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, and the difference from the embodiment 1 is only that the hole 5 is horizontally arranged relative to the horizontal plane.

[0043] Embodiment 3

[0044] The embodiment provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, and the difference from the embodiment 1 is only that the central axis of the hole 5 is inclined upward by an angle of 20 degrees relative to the horizontal plane.

[0045] Embodiment 4

[0046] The embodiment provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, and the difference from the embodiment 1 is only that the central axis of the hole 5 is inclined upward by an angle of 70 degrees relative to the horizontal plane.

[0047] Embodiment 5

[0048] The embodiment provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, and the difference from the embodiment 1 is only that the radial angle of the central axis of the hole 5 is 55 degrees in the radial direction.

[0049] Embodiment 6

[0050] The embodiment provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, and the difference from the embodiment 1 is only that the hole type of the hole is a single-diameter circular hole, and the hole diameter of the hole is 15 mm.

[0051] Embodiment 7

[0052] The embodiment provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, which is basically the same as the structure of the embodiment 1 and comprises a furnace wall outer shell 1, a furnace wall inner shell 2 arranged in the furnace wall outer shell 1, a combustion furnace inner cavity 3 formed in the furnace wall inner shell 2, and a combustion furnace interlayer 4 formed between the furnace wall inner shell 2 and the furnace wall outer shell 1; a plurality of holes 5 are formed in the four circumferential sides of the furnace wall inner shell 2, and the combustion furnace inner cavity 3 and the combustion furnace interlayer 4 are connected through the holes 5 formed in the furnace wall inner shell 2.

[0053] A mixed feed inlet 13 is formed in the bottom of the furnace wall outer shell 1, and is used for feeding the mixture of fuel and oxygen-enriched gas into the combustion furnace inner cavity 3; a combustion tail gas discharge port 7 is formed in the top of the furnace wall outer shell 1, and is connected with the inlet of a waste heat recovery device 8, and is used for discharging the combustion tail gas in the combustion furnace inner cavity and introducing the combustion tail gas into the waste heat recovery device 8.

[0054] A backflow gas inlet 12 is also formed in the bottom of the furnace wall outer shell 1; the outlet of the waste heat recovery device 8 is connected with a flow distribution controller 9, and the combustion tail gas after waste heat recovery is divided into two parts, the first part is used as product gas for oxygen-enriched combustion carbon capture, and the second part is used as backflow gas and returns to the backflow gas inlet 12, enters the combustion furnace interlayer 4, and is injected into the combustion furnace inner cavity 3 through the holes 5 formed in the furnace wall inner shell 2.

[0055] Wherein, along the direction from outside to inside, the holes 5 are inclined upward, so that the backflow gas entering the combustion furnace interlayer 4 is injected into the combustion furnace inner cavity 3 in the direction of upward inclination; the central axis of the holes 5 is inclined upward by an angle of 30 degrees relative to the horizontal plane; along the radial direction, the radial deviation angle of the central axis of the holes 5 is 85 degrees, so that the backflow gas entering the combustion furnace interlayer 4 forms a rotational flow; the hole type of the holes is a tapered hole, the hole diameter of the tapered hole decreases along the direction from outside to inside, the large end diameter of the tapered hole is 10mm, and the small end diameter of the tapered hole is 5mm; the arrangement mode of the holes is a regular triangle arrangement, and the center distance between adjacent two holes is 1.5 times of the large end diameter of the tapered hole.

[0056] Outside the furnace wall outer shell 1, the mixed feed inlet 13 is formed by the combination of a fuel feed inlet 14 and an oxygen-enriched gas inlet 15, the fuel feed inlet 14 is used for feeding fuel, and the oxygen-enriched gas inlet 15 is used for feeding oxygen-enriched gas.

[0057] A heat exchanger 6 is arranged at the top of the combustion furnace inner cavity 3, and is used for realizing heat exchange between the combustion tail gas and the fluid flowing in the heat exchanger 6, and recovering part of the heat of the combustion tail gas.

[0058] The flow controller 9 comprises a flow control valve; a blower 10 is arranged on the pipeline through which the backflow gas returns to the combustion furnace interlayer 4, and a buffer tank 11 is arranged at the outlet of the blower 10.

[0059] Embodiment 8

[0060] The embodiment provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, which is basically the same as the structure of the combustion furnace in Embodiment 1 and comprises a furnace wall outer shell 1, a furnace wall inner shell 2 is arranged in the furnace wall outer shell 1, a combustion furnace inner cavity 3 is formed in the furnace wall inner shell 2, and a combustion furnace interlayer 4 is formed between the furnace wall inner shell 2 and the furnace wall outer shell 1; a plurality of holes 5 are arranged on the four sides of the furnace wall inner shell 2, and the combustion furnace inner cavity 3 and the combustion furnace interlayer 4 are connected through the holes 5 arranged on the furnace wall inner shell 2.

[0061] A mixed feed inlet 13 is arranged at the bottom of the furnace wall outer shell 1, and is used to pass the mixture of fuel and oxygen-enriched gas into the combustion furnace inner cavity 3; a combustion tail gas discharge port 7 is arranged at the top of the furnace wall outer shell 1, and is connected with the inlet of a waste heat recovery device 8, and is used to discharge the combustion tail gas in the combustion furnace inner cavity and introduce the combustion tail gas into the waste heat recovery device 8.

[0062] A backflow gas inlet 12 is further arranged at the bottom of the furnace wall outer shell 1; the outlet of the waste heat recovery device 8 is connected with a flow controller 9, and the combustion tail gas after waste heat recovery is divided into two parts, the first part is used as product gas for oxygen-enriched combustion carbon capture, and the second part is used as backflow gas and returns to the backflow gas inlet 12, enters the combustion furnace interlayer 4, and is injected into the combustion furnace inner cavity 3 through the holes 5 arranged on the furnace wall inner shell 2.

[0063] Wherein, along the direction from outside to inside, the holes 5 are inclined upward, so that the backflow gas entering the combustion furnace interlayer 4 is injected into the combustion furnace inner cavity 3 in an upward inclined direction; the central axis of the hole 5 is inclined upward at an angle of 60 degrees relative to the horizontal plane; along the radial direction, the radial angle of the central axis of the hole 5 is 60 degrees, so that the backflow gas entering the combustion furnace interlayer 4 forms a rotational flow; the hole type of the hole is a tapered hole, the hole diameter of the tapered hole decreases along the direction from outside to inside, the large end diameter of the tapered hole is 20 mm, and the small end diameter of the tapered hole is 15 mm; the arrangement mode of the holes is a regular triangle arrangement, and the center distance between adjacent two holes is 5 times the large end diameter of the tapered hole.

[0064] Outside the furnace wall outer shell 1, the mixed feed inlet 13 is formed by the convergence of a fuel feed inlet 14 and an oxygen-enriched gas inlet 15, the fuel feed inlet 14 is used to pass in fuel, and the oxygen-enriched gas inlet 15 is used to pass in oxygen-enriched gas.

[0065] A heat exchanger 6 is arranged at the top of the combustion furnace inner cavity 3, for exchanging heat between the combustion tail gas and the fluid flowing inside the heat exchanger 6, and recovering part of the heat of the combustion tail gas;

[0066] The flow splitting controller 9 comprises a flow splitting control valve; a blower 10 is arranged on the pipeline through which the backflow gas returns to the combustion furnace interlayer 4, and a buffer tank 11 is arranged at the outlet of the blower 10.

[0067] Comparative Example 1

[0068] The present comparative example provides a common combustion furnace, which is different from Example 1 in that the inner shell of the furnace wall is no longer arranged, so that the structure of the combustion furnace interlayer does not exist, and a part of the combustion tail gas is no longer extracted as backflow gas.

[0069] For the combustion furnaces described in the above examples and comparative examples, the following oxygen-enriched combustion is respectively carried out: the biomass solid fuel made of straw is selected, and the oxygen-enriched gas is 50% oxygen and 50% nitrogen, and the oxygen-enriched combustion is carried out. After the oxygen-enriched combustion is stable, 5 temperature measuring points are uniformly selected on the outside of the inner shell of the furnace wall to measure the temperature and obtain the average outside temperature, and the carbon dioxide content of the product gas is measured, and the related results are summarized in Table 1.

[0070] Table 1

[0071]

[0072]

[0073] Note: " / " indicates that there is no related structure.

[0074] From Table 1, the following points can be seen:

[0075] (1) The present application provides a CO2-rich flue gas injection heat insulation combustion furnace for oxygen-enriched combustion carbon capture, a part of the combustion tail gas is extracted as backflow gas into the combustion furnace interlayer and injected into the combustion furnace inner cavity through the holes opened in the inner shell of the furnace wall, the backflow gas flows along the furnace wall in the combustion furnace inner cavity, forms a cyclone, and serves as a gas film heat insulation layer, reduces the heating effect of the oxygen-enriched combustion reaction in the combustion furnace inner cavity on the furnace wall, and the outside temperature of the inner shell of the furnace wall can be reduced to below 100℃. At the same time, the carbon dioxide concentration in the combustion tail gas is continuously improved after repeated backflow, and the enrichment of carbon dioxide in the product gas is realized, and the carbon dioxide concentration in the tail gas can be increased to more than 40%;

[0076] (2) Comparing Example 1 with Examples 2, 3 and 4, since the upward tilt angle of the holes in the inner shell of the furnace wall in Examples 2 and 3 is small and not within the range of 30-60 degrees, the swirling flow formed by the return gas in the combustion furnace cavity is weak, the insulation effect of the gas film insulation layer is reduced, and the temperature on the outside of the inner shell of the furnace wall is slightly increased. Since the upward tilt angle of the holes in the inner shell of the furnace wall in Example 4 is large and not within the range of 30-60 degrees, although the average temperature on the outside of the inner shell of the furnace wall is basically unchanged, the temperature on the outside of the inner shell of the furnace wall is uneven and the temperature difference is large.

[0077] (3) Comparing Example 1 and Example 5, Example 5 reduces the radial deflection angle of the holes in the inner shell of the furnace wall to 55 degrees, which is not in the range of 60-85 degrees. As a result, the degree of swirling of the return gas adhering to the wall is weaker, the insulation effect of the gas film insulation layer is reduced, and the temperature on the outer side of the inner shell of the furnace wall is uneven with a large temperature difference.

[0078] (4) Comparing Example 1 with Example 6, since Example 6 changed the conical hole to a single round hole, the airflow speed from the outside to the inside was weakened, resulting in a weaker swirling flow of the return gas in the combustion furnace cavity, a reduced insulation effect of the gas film insulation layer, and a slight increase in the temperature of the outer side of the furnace wall inner shell.

[0079] (5) Comparing Example 1 with Comparative Example 1, since Comparative Example 1 no longer has an inner shell of the furnace wall, there is no structure of combustion furnace interlayer. Moreover, a portion of the combustion exhaust gas is no longer extracted as reflux gas, resulting in the outer shell of the furnace wall being directly subjected to the high temperature of oxygen-enriched combustion. The outer temperature of the inner shell of the furnace wall is above 200°C, and the concentration of carbon dioxide in the product gas is only 36%.

[0080] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0081] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0082] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0083] Furthermore, the various embodiments can also be combined, if not in contradiction, as long as they do not deviate from the spirit of the present application, which should be considered as disclosed.

Claims

1. A CO2-rich flue gas injection insulated combustion furnace for oxygen enriched combustion carbon capture, characterized in that, The furnace wall outer shell is provided with a furnace wall inner shell inside the furnace wall outer shell, an inner cavity of the furnace wall inner shell forms a combustion furnace inner cavity, and a combustion furnace interlayer is formed between the furnace wall inner shell and the furnace wall outer shell; a hole is formed in the four peripheral sides of the furnace wall inner shell, and the combustion furnace inner cavity and the combustion furnace interlayer are connected through the hole formed in the furnace wall inner shell; A mixed feed inlet is formed in the bottom of the furnace wall outer shell, and the mixed feed inlet is used to pass a mixture of fuel and oxygen-rich gas into the combustion furnace inner cavity; a combustion tail gas discharge port is formed in the top of the furnace wall outer shell, and the combustion tail gas discharge port is connected with an inlet of a waste heat recovery device, and is used to discharge combustion tail gas in the combustion furnace inner cavity and introduce the combustion tail gas into the waste heat recovery device; The bottom of the furnace wall outer shell is also provided with a backflow gas inlet; an outlet of the waste heat recovery device is connected with a flow distribution controller, and the combustion tail gas recovered by the waste heat recovery device is divided into two parts, a first part is used as product gas for oxygen-enriched combustion carbon capture, and a second part is used as backflow gas and returned to the backflow gas inlet, enters the combustion furnace interlayer, and is sprayed into the combustion furnace inner cavity through the hole formed in the furnace wall inner shell.

2. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture according to claim 1, characterized in that, In a direction from outside to inside, the hole is inclined upward, so that the backflow gas entering the combustion furnace interlayer is sprayed into the combustion furnace inner cavity in an upward inclined direction.

3. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture according to claim 2, characterized in that, The central axis of the hole is inclined upward at an angle of 30-60 degrees with respect to the horizontal plane.

4. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture of claim 1, wherein, In a radial direction, the radial deviation angle of the central axis of the hole is 60-85 degrees, so that the backflow gas entering the combustion furnace interlayer forms a rotational flow.

5. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture according to claim 2 or 4, characterized in that, The hole type of the hole is a tapered hole, the hole diameter of the tapered hole decreases in a direction from outside to inside, the large end diameter of the tapered hole is 3-20 mm, and the small end diameter of the tapered hole is 2-15 mm.

6. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture according to claim 2 or 4, characterized in that, The arrangement mode of the hole is a regular triangle arrangement or a square arrangement, and the center distance between adjacent two holes is 1.5-10 times the hole diameter.

7. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture of claim 1, wherein, Outside the furnace wall outer shell, the mixed feed inlet is formed by the combination of a fuel feed inlet and an oxygen-rich gas inlet, the fuel feed inlet is used to pass fuel, and the oxygen-rich gas inlet is used to pass oxygen-rich gas.

8. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture of claim 1, wherein, A heat exchanger is arranged at the top of the combustion furnace inner cavity, and is used to exchange heat between the combustion tail gas and a fluid flowing in the heat exchanger, and recover part of the heat of the combustion tail gas.

9. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture of claim 1, wherein, The flow distribution controller comprises a flow distribution control valve.

10. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture of claim 1, wherein, A blower is arranged on a pipeline through which the backflow gas returns to the combustion furnace interlayer.

11. The CO2 -enriched flue gas ejection insulated combustion furnace for oxygen- enriched combustion carbon capture according to claim 10, characterized in that, A buffer tank is arranged at the outlet of the blower.

Images