Chemical looping system coupled with fluidized bed boiler

Abstract

The utility model relates to the technical field of boilers, and discloses a chemical looping system of a coupled fluidized bed boiler, which comprises a fluidized bed system, a chemical looping system, a blanking pipe and a first material returning device, the fluidized bed system is communicated with the chemical looping system through the blanking pipe, and the fluidized bed system is communicated with the chemical looping system through the first material returning device. According to the utility model, the problems of high carbon capture cost and high one-time investment of a chemical looping technology in the carbon capture technology in the prior art are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of boilers, in particular to a chemical chain system coupled with a fluidized bed boiler. Background Art

[0002] At present, CO2 emissions from my country's power industry account for over 40% of the nation's total emissions. Reducing CO2 emissions from coal-fired power units is of great significance to achieving carbon neutrality for the power industry and the nation. Coal-fired power plant carbon capture routes are divided into pre-combustion carbon capture, post-combustion carbon capture, oxygen-enriched combustion, and chemical chaining. Most power plants use post-combustion capture technology, adding a CO2 capture system to the tail of the boiler. Due to the low concentration of CO2 in the flue gas, the carbon capture cost of this system is relatively high. Oxygen-enriched combustion uses an air separation unit to separate oxygen and nitrogen from the air, and uses pure oxygen to react with fuel to produce pure CO2. This can reduce the cost of carbon capture in the flue gas, but the high cost of the air separation unit makes the overall carbon capture cost higher than post-combustion capture. Chemical looping is a new carbon capture technology that primarily consists of an air reactor and a fuel reactor. In the air reactor, an oxygen carrier reacts with oxygen in the air to produce a high-valent oxygen carrier. This oxygen is then transported to the fuel reactor, where the fuel reacts with the oxygen in the high-valent oxygen carrier to produce a low-valent oxygen carrier, CO₂, and H₂O. The low-valent oxygen carrier is then returned to the air reactor, where the flue gas is condensed to produce a high-concentration CO₂. Chemical looping combustion technology reduces the cost of flue gas carbon capture, but its dual-bed structure increases the initial investment. Utility Model Content

[0003] In order to overcome the deficiencies of the prior art, the utility model provides a chemical looping system coupled with a fluidized bed boiler, which solves the problems of high carbon capture cost and high one-time investment of the chemical looping technology in the prior art.

[0004] The technical solution adopted by the present invention to solve the above problems is:

[0005] A chemical loop system coupled with a fluidized bed boiler includes a fluidized bed system, a chemical loop system, a feed pipe, and a first returner. The fluidized bed system is connected to the chemical loop system through the feed pipe, and the fluidized bed system is connected to the chemical loop system through the first returner.

[0006] As a preferred technical solution, the fluidized bed system includes a furnace, a second cyclone separator, and a tail flue connected in sequence. The fluidized bed system also includes a second return material feeder. The second cyclone separator is also connected to the furnace through the second return material feeder. The chemical chain system includes a fuel reactor, a riser, a first cyclone separator, and a waste heat utilization system connected in sequence. The waste heat utilization system is connected to a recycling flue and an outlet flue. The waste heat utilization system, the recycling flue, and the fuel reactor are connected in sequence. The furnace is connected to the chemical chain system through the fuel reactor, and the furnace is connected to the first cyclone separator through the first return material feeder.

[0007] As a preferred technical solution, the fuel reactor is provided with a coal feeding pipe, an accident slag discharge pipe, and a fluidized air chamber.

[0008] As a preferred technical solution, a recirculation fan is provided on the recirculation flue.

[0009] As a preferred technical solution, an ash control valve is provided on the discharge pipe.

[0010] As a preferred technical solution, the cross-sectional shape of the fuel reactor is circular or rectangular; if the cross-sectional shape is circular, 1≤m / n≤3, where m is the height of the fuel reactor and n is the diameter of the cross-sectional shape; if the cross-sectional shape is rectangular, the ratio of the height of the fuel reactor to the length of the rectangle is in the range of 1~3, or the ratio of the height of the fuel reactor to the width of the rectangle is in the range of 1~3.

[0011] As a preferred technical solution, the bottom of the fuel reactor is shrunk, and the shrinkage ratio range is 0.3≤p / n≤0.8; wherein p is the diameter of the bottom of the fuel reactor after shrinkage.

[0012] As a preferred technical solution, assuming that the material layer height during operation of the fuel reactor is a, the height of the feed port is b, the height of the coal feed port is c, and the height of the slag discharge port is d, then:

[0013] The range of a is 1 meter ≤ a ≤ 6 meters, the range of b is a-2 meters ≤ b ≤ a+2 meters, the range of c is a-2 meters ≤ c ≤ a+2 meters, and the range of d is 0.1 meter ≤ d ≤ 1 meter.

[0014] As a preferred technical solution, the range of the diameter ratio of the riser to the fuel reactor is 0.2≤e / n≤0.95; wherein e represents the diameter of the riser.

[0015] As a preferred technical solution, assuming that the opening position of the discharge pipe is at a height h from the bottom of the furnace, the height of the discharge pipe is i, the inclination angle of the discharge pipe is p, the height of the lifting pipe is j, and the height of the first return pipe is k, then:

[0016] The range of h is 0 m < h ≤ 1 m, the range of i is i ≥ 4 m, the range of p is p ≥ 45°, the range of j is j ≥ 8 m, and the range of k is k ≥ 2 m.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The utility model can enrich high-concentration CO2 and reduce the carbon capture cost of coal-fired units;

[0019] (2) The utility model can generate high-quality steam with good economic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a chemical looping system coupled to a fluidized bed boiler;

[0021] Figure 2 Schematic diagram of a fuel reactor for coupling a fluidized bed boiler chemical looping system;

[0022] Figure 3 Schematic diagram of the material circulation loop of the chemical looping system coupled with a fluidized bed boiler.

[0023] The symbols and their corresponding names in the accompanying drawings are: 2. Fuel reactor, 3. Circulating material, 4. Downcomer, 5. Lifting pipe, 6. First cyclone separator, 7. First return material collector, 8. Waste heat utilization system, 9. Recirculation flue, 10. Outlet flue, 11. Furnace, 12. Second cyclone separator, 13. Second return material collector, 14. Tail flue, 21. Coal feeding pipe, 22. Accident slag discharge pipe, 23. Fluidizing air chamber, 41. Ash control valve, 91. Recirculation fan. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the embodiments and drawings, but the implementation manner of the present invention is not limited thereto.

[0025] Example 1

[0026] like Figures 1 to 3 To reduce the carbon capture costs of fluidized bed boilers (which can be fueled by coal, biomass, or other carbon-containing fuels), this utility model provides a chemical looping system coupled to the fluidized bed boiler. This system allows for the low-cost capture of some or all of the CO2 produced during combustion, enabling the retrofit or construction of new fluidized bed boilers. This system can enrich high-concentration CO2, reducing the carbon capture costs of the fluidized bed boiler. It also produces high-quality steam, resulting in excellent economic efficiency.

[0027] Figure 1A chemical looping system coupled to a fluidized bed boiler is shown, comprising a fluidized bed system and a chemical looping system. The fluidized bed system primarily comprises the fluidized bed boiler furnace 11, a second cyclone separator 12, a second recirculator 13, and a tail flue 14; the chemical looping system comprises a fuel reactor 2, a circulating material 3, a downpipe 4, a riser 5, a first cyclone separator 6, a first recirculator 7, a waste heat utilization system 8, a recirculation flue 9, and an outlet flue 10.

[0028] The discharge pipe 4 is provided with an ash control valve 41 for adjusting the discharge flow rate.

[0029] The fuel reactor 2 is provided with a coal feeding pipe 21 , an emergency slag discharge pipe 22 , and a fluidizing air chamber 23 .

[0030] A recirculation fan 91 is provided on the recirculation flue 9 .

[0031] The second material return device 13 and the first material return device 7 are U-shaped material return devices.

[0032] The circulating material 3 is a mixture of oxygen carrier and coal ash, the particle size of the oxygen carrier is between 100 and 1000 μm, and the mass proportion of the oxygen carrier is between 30 and 95%.

[0033] The fluidized bed boiler's furnace 11, second cyclone separator 12, and second material return device 13 form the fluidized bed boiler's primary circulation loop. During normal operation, the circulating material circulates within this primary circulation loop. The fluidized bed system can operate independently as a coal-fired boiler or in conjunction with a chemical looping system.

[0034] The furnace 11 is connected to the discharge pipe 4, the discharge pipe 4 is connected to the fuel reactor 2, the fuel reactor 2 is connected to the riser 5, the riser 5 is connected to the first cyclone separator 6, the lower part of the first cyclone separator 6 is connected to the first return material device 7, the first return material device 7 is connected to the furnace 11, the upper part of the first cyclone separator 6 is connected to the waste heat utilization system 8, the outlet flue of the waste heat utilization system 8 is divided into two, respectively connected to the recycling flue 9 and the outlet flue 10, the recycling flue 9 is connected to the fluidizing air chamber 23 of the fuel reactor 2, and the outlet flue 10 is connected to the flue gas purification system and the carbon capture system, thereby obtaining high-concentration CO2.

[0035] Figure 2 A fuel reactor for coupling a fluidized bed boiler chemical looping system is demonstrated.

[0036] The cross section of the fuel reactor 2 is preferably circular, with a height of m and a diameter of n. To avoid vibration during operation of the fuel reactor, the height-to-diameter ratio is in the range of 1≤m / n≤3.

[0037] The cross section of the fuel reactor 2 may also be rectangular, with the ratio of the height to the length or width of the rectangle being in the range of 1 to 3.

[0038] The bottom of the fuel reactor 2 is contracted, the diameter of the air distribution plate is p, and the contraction ratio range is 0.3≤p / n≤0.8.

[0039] The fuel reactor 2 is a fluidized bed reactor. The material layer height during operation (from the air distribution plate, the same below) is a, the height of the feed port is b, the height of the coal feeding port is c, and the height of the slag discharge port is d.

[0040] The range of the material layer height a is 1 meter ≤ a ≤ 6 meters.

[0041] The range of the feed port height b is a-2 meters ≤ b ≤ a+2 meters.

[0042] The range of the coal feeding port height c is a-2 meters ≤ c ≤ a+2 meters.

[0043] The range of the slag discharge port height d is 0.1 m ≤ d ≤ 1 m.

[0044] The diameter of the riser 5 is e, and the ratio of the diameter of the riser to the diameter of the fuel reactor is in the range of 0.2≤e / n≤0.95.

[0045] Figure 3 The material circulation loop of the chemical chain system coupled with the fluidized bed boiler is shown. The chemical reaction of the circulating material 3 in the fluidized bed furnace 11 is: x O y-1 +O2→M x O y The chemical reaction of the circulating material 3 in the fuel reactor is: C m H n +M x O y →CO2+H2O+ M x O y-1 ;The overall reaction equation is: C m H n + O2→CO2+H2O. The gas products of the fuel reactor are only CO2 and H2O, which can be enriched with high concentrations of CO2.

[0046] The circulating material 3 is conveyed as follows: from the fluidized bed furnace 11 to the fuel reactor 2 by gravity, from the fuel reactor 2 to the separator 6 by pneumatic conveying, from the separator 6 to the first return material collector 7 by cyclone separation, and from the first return material collector 7 to the fluidized bed furnace 11 by gravity.

[0047] The opening position of the discharge pipe 4 is at a height h from the air distribution plate of the furnace 11, and the range of h is 0 meter < h ≤ 1 meter.

[0048] The height of the feeding pipe 4 is i, and the range of i is i≥4 meters.

[0049] The inclination angle of the feeding pipe 4 is p, and the range of p is p≥45°.

[0050] The height of the riser 5 is j, and the range of j is j≥8 meters.

[0051] The height of the vertical pipe of the first material return device 7 is k, and the range of k is k≥2 meters.

[0052] Preferably, the particle size of the oxygen carrier is between 100 and 1000 μm, and the mass proportion of the oxygen carrier is between 30 and 95%.

[0053] Preferably, the fluidized bed system can be operated independently as a coal-fired boiler or can be coupled with a chemical looping system.

[0054] Example 2

[0055] like Figures 1 to 3 As shown, as a further optimization of Example 1, based on Example 1, this embodiment also includes the following technical features:

[0056] like Figure 1 Figure 1 shows a chemical looping system coupled to a fluidized bed boiler, comprising a fluidized bed system and a chemical looping system. The fluidized bed system primarily comprises the fluidized bed boiler furnace 11, a second cyclone separator 12, a second recirculator 13, and a tail flue 14. The chemical looping system comprises a fuel reactor 2, a circulating material 3, a downpipe 4, a riser 5, a first cyclone separator 6, a first recirculator 7, a waste heat utilization system 8, a recirculation flue 9, and an outlet flue 10.

[0057] An ash control valve 41 is provided on the discharge pipe for adjusting the discharge flow rate.

[0058] The fuel reactor 2 is provided with a coal feeding pipe 21 , an emergency slag discharge pipe 22 , and a fluidizing air chamber 23 .

[0059] A recirculation fan 91 is provided on the recirculation flue 9 .

[0060] The second material return device 13 and the first material return device 7 are U-shaped material return devices.

[0061] The circulating material 3 is a mixture of oxygen carrier and coal ash. The particle size of the oxygen carrier is about 200um, and the mass proportion of the oxygen carrier is 40%.

[0062] The fluidized bed boiler's furnace 11, second cyclone separator 12, and second material return device 13 form the fluidized bed boiler's main circulation loop. During normal operation, the circulating material circulates within this main circulation loop. The fluidized bed system can operate independently as a coal-fired boiler or in conjunction with a portion of a chemical looping system.

[0063] The furnace 11 is connected to the discharge pipe 4, the discharge pipe 4 is connected to the fuel reactor 2, the fuel reactor 2 is connected to the riser 5, the riser 5 is connected to the first cyclone separator 6, the lower part of the first cyclone separator 6 is connected to the first return material device 7, the first return material device 7 is connected to the furnace 11, the upper part of the first cyclone separator 6 is connected to the waste heat utilization system 8, the outlet flue of the waste heat utilization system is divided into two, respectively connected to the recycling flue 9 and the outlet flue 10, the recycling flue 9 is connected to the fluidizing air chamber 23 of the fuel reactor 2, and the outlet flue 10 is connected to the flue gas purification system and the carbon capture system, thereby obtaining high-concentration CO2.

[0064] like Figure 2 FIG. 1 shows a fuel reactor for coupling a fluidized bed boiler chemical looping system.

[0065] The cross section of the fuel reactor 2 is preferably circular, with a height of 5 meters and a diameter of 2 meters. To avoid vibration during operation of the fuel reactor, the height-to-diameter ratio m / n is 2.5.

[0066] The bottom of the fuel reactor 2 is contracted, the diameter of the air distribution plate is 1 meter, and the contraction ratio p / n is 0.5.

[0067] The fuel reactor 2 is a fluidized bed reactor. The material layer height (from the air distribution plate, the same below) a during operation is 2 meters, the height b of the feed port is 3 meters, the height c of the coal feeding port is 3 meters, and the height d of the slag discharge port is 0.5 meters.

[0068] The diameter e of the riser 5 is 1 meter, and the ratio e / n of the diameter of the riser to the fuel reactor is 0.5.

[0069] like Figure 3 As shown, a material circulation loop of a chemical chain system coupled to a fluidized bed boiler. The chemical reaction of the circulating material 3 in the fluidized bed furnace 11 is: x O y-1 +O2→M x O y The chemical reaction of the circulating material 3 in the fuel reactor is: C m H n + M x O y →CO2+H2O+ M x O y-1 ;The overall reaction equation is: C m H n + O2→CO2+H2O. The gas products of the fuel reactor are only CO2 and H2O, which can be enriched with high concentrations of CO2.

[0070] The circulating material 3 is conveyed as follows: from the fluidized bed furnace 11 to the fuel reactor 2 by gravity, from the fuel reactor 2 to the separator 6 by pneumatic conveying, from the separator 6 to the first return material collector 7 by cyclone separation, and from the first return material collector 7 to the fluidized bed furnace 11 by gravity.

[0071] The opening position of the discharge pipe 4 is at a height h of 0.5 meters from the air distribution plate of the furnace 11.

[0072] The height i of the feed pipe 4 is 6 meters.

[0073] The inclination angle p of the feed pipe 4 is 60°.

[0074] The height j of the riser 5 is 20 meters.

[0075] The height k of the vertical pipe of the first return feeder 7 is 4 meters.

[0076] As described above, the present invention can be implemented well.

[0077] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Based on the technical essence of the present invention and within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement of the above embodiment shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A chemical looping system coupled with a fluidized bed boiler, characterized in that: The fluidized bed system comprises a fluidized bed system, a chemical chain system, a feed pipe (4), and a first return material device (7). The fluidized bed system is connected to the chemical chain system via the feed pipe (4), and the fluidized bed system is connected to the chemical chain system via the first return material device (7).

2. A chemical looping system coupled with a fluidized bed boiler according to claim 1, characterized in that: The fluidized bed system comprises a furnace (11), a second cyclone separator (12), and a tail flue (14) which are connected in sequence. The fluidized bed system also comprises a second return material device (13). The second cyclone separator (12) is further connected to the furnace (11) through the second return material device (13). The chemical chain system comprises a fuel reactor (2), a riser (5), a first cyclone separator (6), and a waste heat utilization system (8) which are connected in sequence. The waste heat utilization system (8) is connected to a recirculation flue (9) and an outlet flue (10). The waste heat utilization system (8), the recirculation flue (9), and the fuel reactor (2) are connected in sequence. The furnace (11) is connected to the chemical chain system through the fuel reactor (2). The furnace (11) is connected to the first cyclone separator (6) through the first return material device (7).

3. A chemical looping system coupled with a fluidized bed boiler according to claim 2, characterized in that: The fuel reactor (2) is provided with a coal feeding pipe (21), an accident slag discharge pipe (22), and a fluidizing air chamber (23).

4. A chemical looping system coupled to a fluidized bed boiler according to claim 2, characterized in that: A recirculation fan (91) is provided on the recirculation flue (9).

5. The chemical looping system coupled with a fluidized bed boiler according to claim 2, characterized in that: An ash control valve (41) is provided on the discharge pipe (4).

6. The chemical looping system coupled with a fluidized bed boiler according to claim 2, characterized in that: The cross-sectional shape of the fuel reactor (2) is circular or rectangular; if the cross-sectional shape is circular, 1≤m / n≤3, wherein m is the height of the fuel reactor (2) and n is the diameter of the cross-sectional shape; if the cross-sectional shape is rectangular, the ratio of the height of the fuel reactor (2) to the length of the rectangle is in the range of 1 to 3, or the ratio of the height of the fuel reactor (2) to the width of the rectangle is in the range of 1 to 3.

7. A chemical looping system coupled to a fluidized bed boiler according to claim 6, characterized in that: The bottom of the fuel reactor (2) is contracted, and the contraction ratio range is 0.3≤p / n≤0.8; wherein p is the diameter of the bottom of the fuel reactor (2) after contraction.

8. The chemical looping system coupled with a fluidized bed boiler according to claim 2, characterized in that: Assuming that the material layer height of the fuel reactor (2) during operation is a, the height of the feed port is b, the height of the coal feed port is c, and the height of the slag discharge port is d, then: The range of a is 1 meter ≤ a ≤ 6 meters, the range of b is a-2 meters ≤ b ≤ a+2 meters, the range of c is a-2 meters ≤ c ≤ a+2 meters, and the range of d is 0.1 meter ≤ d ≤ 1 meter.

9. The chemical looping system coupled with a fluidized bed boiler according to claim 2, characterized in that: The range of the diameter ratio of the riser (5) to the fuel reactor (2) is 0.2≤e / n≤0.95; wherein e represents the diameter of the riser (5).

10. A chemical looping system coupled to a fluidized bed boiler according to any one of claims 2 to 9, characterized in that: Assume that the height of the opening of the discharge pipe (4) from the bottom of the furnace (11) is h, the height of the discharge pipe (4) is i, the inclination angle of the discharge pipe (4) is p, the height of the lifting pipe (5) is j, and the height of the vertical pipe of the first return device (7) is k, then: The range of h is 0 m < h ≤ 1 m, the range of i is i ≥ 4 m, the range of p is p ≥ 45°, the range of j is j ≥ 8 m, and the range of k is k ≥ 2 m.

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