Boiler combustion system

Abstract

The utility model relates to the technical field of coal-fired boilers for mixed combustion of hydrogen, in particular to a boiler combustion system which comprises a combustor, a boiler, a gas mixer, a hydrogen supply subsystem, a smoke supply subsystem and an air supply system, the combustor is connected to the boiler, and the combustor is provided with a first gas conveying cavity and a second gas conveying cavity which are communicated with a boiler cavity of the boiler; the gas outlet end of the hydrogen supply subsystem and the gas outlet end of the flue gas supply subsystem both communicate with the gas inlet end of the gas mixer, the gas outlet end of the gas mixer communicates with the second gas conveying cavity, and hydrogen and flue gas are premixed in the gas mixer and then introduced into the combustor; flue gas contains smoke dust, carbon dioxide and other components which are high in radiation capacity and do not have a heating value, the flue gas and hydrogen are mixed and then combusted, the combustion peak temperature of the hydrogen can be reduced, meanwhile, due to the fact that mixed gas contains the components which are high in radiation capacity of the flue gas, the flame radiation capacity is improved, flame heat can be transmitted as soon as possible, and the combustion efficiency is improved. And overtemperature of the heating surface in the furnace can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of coal-fired boilers that co-fire hydrogen, and in particular to a boiler combustion system. Background Technology

[0002] One method to reduce carbon dioxide emissions from coal-fired boilers is by blending them with low-carbon or zero-carbon fuels. Hydrogen, produced from renewable energy sources, is a globally recognized carbon-free fuel. Blending hydrogen in a certain proportion in a coal-fired boiler can reduce carbon dioxide emissions at the source. However, hydrogen combustion is characterized by high localized flame temperatures and weak radiation. When boilers designed for coal combustion blend with hydrogen, localized overheating can easily occur, leading to excessive nitrogen oxide emissions and overheating of the furnace heating surfaces, thus affecting the safe operation of the boiler. Utility Model Content

[0003] Based on this, the purpose of this utility model is to provide a boiler combustion system, including a burner, a boiler, a gas mixer, a hydrogen supply subsystem, a flue gas supply subsystem, and an air supply subsystem. The burner is connected to the boiler and has a first gas delivery chamber and a second gas delivery chamber that communicate with the furnace chamber of the boiler. The air supply subsystem communicates with the first gas delivery chamber. The outlet of the hydrogen supply subsystem and the outlet of the flue gas supply subsystem are both communicated with the inlet of the gas mixer. The outlet of the gas mixer communicates with the second gas delivery chamber.

[0004] As a preferred embodiment, the burner also has a third gas supply chamber. The air supply subsystem includes a primary air supply pipe, a secondary air supply pipe, and an air supply device. Both the primary air supply pipe and the secondary air supply pipe are connected to the air supply device. The end of the primary air supply pipe away from the air supply device is connected to the first gas supply chamber, and the end of the secondary air supply pipe away from the air supply device is connected to the third gas supply chamber.

[0005] As a preferred embodiment, the burner includes a central tube, a first sleeve sleeved outside the central tube, and a second sleeve sleeved outside the first sleeve.

[0006] The lumen of the central tube forms the first gas delivery chamber, the structure between the inner wall of the first sleeve and the outer wall of the central tube forms the second gas delivery chamber, and the inner wall of the second sleeve and the outer wall of the first sleeve form the third gas delivery chamber.

[0007] As a preferred embodiment, the flue gas supply subsystem includes an induced draft fan, one end of which is connected to the flue gas pipe of the boiler, and the other end of which is connected to the gas mixer.

[0008] As a preferred embodiment, the boiler combustion system further includes an air preheater, which has a first heat exchange chamber and a second heat exchange chamber capable of heat exchange.

[0009] The exhaust pipe, the first heat exchange chamber, the induced draft fan, and the gas mixer are connected in sequence.

[0010] The air supply device includes a first fan, the air outlet of the first fan is connected to one end of the third air supply chamber, and the end of the primary air supply pipe away from the first air supply chamber and the end of the secondary air supply pipe away from the third air supply chamber are both connected to the other end of the third air supply chamber.

[0011] As a preferred embodiment, the air preheater has a third heat exchange chamber that can exchange heat with the first heat exchange chamber, and the boiler combustion system includes a second fan and a pulverized coal supply device with a pulverized coal outlet chamber, wherein the second fan, the third heat exchange chamber, the pulverized coal outlet chamber and the pulverized coal inlet of the boiler are connected in sequence.

[0012] As a preferred embodiment, the boiler combustion system further includes a first pipe body, one end of which is connected to the air outlet of the second fan, and the other end is connected to the powder outlet chamber. A first control valve is provided on the first pipe body.

[0013] As a preferred embodiment, the boiler combustion system further includes a second tube body, one end of which is connected to the third heat exchange chamber and the other end of which is connected to the pulverized coal outlet chamber. A second control valve is provided on the second tube body.

[0014] As a preferred embodiment, the hydrogen supply subsystem includes a hydrogen supply device, a fourth pipe body, and a fourth control valve. One end of the fourth pipe body is connected to the hydrogen supply device, and the other end is connected to the gas mixer. The fourth control valve is disposed on the fourth pipe body.

[0015] The boiler combustion system includes a fifth tube and a fifth control valve. One end of the fifth tube is connected to the air outlet of the induced draft fan, and the other end is connected to the gas mixer. The fifth control valve is installed on the fifth tube.

[0016] As a preferred embodiment, the boiler combustion system further includes a third tube, one end of which is connected to the gas outlet of the gas mixer and the other end of which is connected to the second gas delivery chamber. A third control valve is provided on the third tube.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0018] This utility model discloses a boiler combustion system, comprising a burner, a boiler, a gas mixer, a hydrogen supply subsystem, a flue gas supply subsystem, and an air supply subsystem. The burner is connected to the boiler and has a first gas delivery chamber and a second gas delivery chamber connected to the boiler's furnace chamber. The air supply subsystem is connected to the first gas delivery chamber and can supply air to it. The outlets of both the hydrogen supply subsystem and the flue gas supply subsystem are connected to the inlet of the gas mixer. The outlet of the gas mixer is connected to the second gas delivery chamber. Hydrogen and flue gas are premixed in the gas mixer before being fed into the burner. The flue gas contains components with strong radiation capabilities, such as soot and carbon dioxide, but without calorific value. The mixed combustion of flue gas and hydrogen reduces the peak flame temperature and, moreover, produces a flame with stronger radiation capabilities than that of pure hydrogen combustion, which facilitates rapid heat transfer and prevents overheating of the furnace heating surfaces, thus ensuring the safe operation of the boiler. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the boiler combustion system of this utility model;

[0020] Figure 2 This is a schematic diagram of the burner's structure;

[0021] In the diagram, 1. Burner, 11. Central pipe, 12. First sleeve, 13. Second sleeve, 101. First gas delivery chamber, 102. Second gas delivery chamber, 103. Third gas delivery chamber, 2. Boiler, 3. Gas mixer, 41. Exhaust fan, 42. First fan, 43. Second fan, 5. Air preheater, 6. Pulverized coal supply device, 71. First pipe body, 72. Second pipe body, 73. Third pipe body, 74. Fourth pipe body, 75. Fifth pipe body, 76. Primary air delivery pipe, 77. Secondary air delivery pipe, 78. Main air duct, 81. First control valve, 82. Second control valve, 83. Third control valve, 84. Fourth control valve, 85. Fifth control valve, 86. Sixth control valve, 9. Hydrogen supply device. Detailed Implementation

[0022] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0023] In the description of this utility model, it should be understood that the terms "upper," "lower," "left," "right," "top," and "bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. It should be understood that the terms "first," "second," etc., are used in this utility model to describe various information, but this information should not be limited to these terms; these terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this utility model, "first" information can also be called "second" information, and similarly, "second" information can also be called "first" information.

[0024] like Figure 1 , Figure 2As shown, a preferred embodiment of the boiler combustion system of this utility model includes a burner 1, a boiler 2, a gas mixer 3, a hydrogen supply subsystem, a flue gas supply subsystem, and an air supply subsystem. The burner 1 is connected to the boiler 2 and has a first gas delivery chamber 101 and a second gas delivery chamber 102 communicating with the furnace cavity of the boiler 2. The air supply subsystem is connected to the first gas delivery chamber 101. The outlet ends of the hydrogen supply subsystem and the flue gas supply subsystem are both connected to the inlet end of the gas mixer 3, and the outlet end of the gas mixer 3 is connected to the second gas delivery chamber 102. The flue gas contains a certain proportion of dust, carbon dioxide, and other components with strong radiation capabilities. After being mixed with hydrogen for combustion, the characteristic that the combustion products of pure hydrogen are only water is changed, which can enhance the flame radiation capability, thereby reducing the ignition rate and the peak flame temperature. On the one hand, this is conducive to the rapid transfer of flame heat, and on the other hand, it can also reduce the impact of fuel changes on heat exchange in the furnace. Pure hydrogen combustion produces water vapor. Water vapor has low emissivity at temperatures between 900℃ and 2000℃, contributing to localized high temperatures during combustion. When hydrogen mixes with the flue gas from boiler 2, particulate matter is mixed into the hydrogen along with the flue gas. During combustion, this particulate matter is heated by the flame, enhancing the flame's outward radiation and accelerating heat transfer to some extent, thus suppressing the peak flame temperature. Furthermore, the flue gas has a relatively low oxygen content, making its mixing with hydrogen highly safe and requiring no special explosion-proof measures. The ratio of flue gas to hydrogen can be adjusted according to the capacity of boiler 2 and the combustion process control. A lower hydrogen percentage results in a lower peak flame temperature, but a higher extracted flue gas volume increases the power consumption for flue gas recovery to burner 1; conversely, a lower extracted flue gas volume fails to reduce the peak flame temperature. Typically, the hydrogen-to-flue gas volume ratio is 3:7 to 9:1. The specific ratio needs to be comprehensively analyzed based on factors such as the calorific value ratio of hydrogen to coal and the size of the boiler to select the optimal ratio of hydrogen to flue gas. In the blending ratio of hydrogen to pulverized coal, the calorific value of the coal should not be less than 20%, and is typically 50%.

[0025] To ensure complete combustion of hydrogen, in this embodiment, the burner 1 also has a third gas supply chamber 103. The air supply subsystem includes a primary air supply pipe 76, a secondary air supply pipe 77, and an air supply device. Both the primary air supply pipe 76 and the secondary air supply pipe 77 are connected to the air supply device. The end of the primary air supply pipe 76 away from the air supply device is connected to the first gas supply chamber 101, and the end of the secondary air supply pipe 77 away from the air supply device is connected to the third gas supply chamber 103. The burner 1 includes a central pipe 11, a first sleeve 12 sleeved outside the central pipe 11, and a second sleeve 13 sleeved outside the first sleeve 12. The lumen of the central pipe 11 forms the first gas supply chamber 101. The structure between the inner wall of the first sleeve 12 and the outer wall of the central pipe 11 forms the second gas supply chamber 102, and the inner wall of the second sleeve 13 and the outer wall of the first sleeve 12 form the third gas supply chamber 103. The third gas delivery chamber 103 has a columnar ring structure, surrounding the first gas delivery chamber 101 and the second gas delivery chamber 102. The innermost first gas delivery chamber 101 is a primary air channel. The primary air in the first gas delivery chamber 101 provides ignition and combustion-stabilizing air to the mixed gas flowing out of the second gas delivery chamber 102 in a diffusion manner. The greater the difference in outlet airflow velocity between the first gas delivery chamber 101 and the second gas delivery chamber 102, the stronger the mixing of air and mixed gas. The third gas delivery chamber 103 provides other air required for subsequent combustion, also providing combustion-supporting air to hydrogen through diffusion mixing.

[0026] In this embodiment, the flue gas supply subsystem includes an induced draft fan 41, one end of which is connected to the exhaust pipe of the boiler 2, and the other end is connected to the gas mixer 3. By using the flue gas generated by the boiler 2 as the flue gas source, the thermal efficiency of the boiler combustion system of this invention is improved.

[0027] The boiler combustion system also includes an air preheater 5, which has a first heat exchange chamber and a second heat exchange chamber for heat exchange. The flue pipe, the first heat exchange chamber, the induced draft fan 41, and the gas mixer 3 are sequentially connected. The air supply device includes a first fan 42, the outlet of which is connected to one end of a third air supply chamber 103. The ends of the primary air supply pipe 76 away from the first air supply chamber 101 and the secondary air supply pipe 77 away from the third air supply chamber 103 are both connected to the other end of the third air supply chamber 103. The air preheater 5 can utilize the waste heat of the flue gas to preheat the primary and secondary air, further improving the thermal efficiency of the boiler combustion system of this invention. In this embodiment, to facilitate adjustment of the flow ratio of primary and secondary air, a flow control valve 86 is provided on the primary air supply pipe. By increasing the flow control valve 86, the ratio of primary air to secondary air can be increased.

[0028] Furthermore, in this embodiment, the air preheater 5 has a third heat exchange chamber capable of exchanging heat with the first heat exchange chamber. The boiler combustion system also includes a second fan 43 and a pulverized coal supply device 6 with a pulverized coal outlet chamber. In this embodiment, the pulverized coal supply device 6 is a coal mill. The second fan 43, the third heat exchange chamber, the pulverized coal outlet chamber, and the first air conveying chamber 101 are sequentially connected. The air preheater 5 can preheat not only the primary and secondary air but also the air used to blow pulverized coal into the boiler.

[0029] To facilitate the adjustment of pulverized coal temperature, in this embodiment, the boiler combustion system further includes a first pipe body 71. One end of the first pipe body 71 is connected to the air outlet of the second fan 43, and the other end is connected to the pulverized coal outlet chamber. A first control valve 81 is provided on the first pipe body 71. By increasing the pressure of the first control valve 81, the temperature of the pulverized coal can be reduced.

[0030] Furthermore, the boiler combustion system also includes a second tube 72, one end of which is connected to the third heat exchange chamber and the other end to the pulverized coal outlet chamber. A second control valve 82 is provided on the second tube 72. By increasing the pressure of the first control valve 81 and decreasing the pressure of the second control valve 82, the temperature of the pulverized coal can be reduced; conversely, by decreasing the pressure of the first control valve 81 and increasing the pressure of the second control valve 82, the temperature of the pulverized coal can be increased.

[0031] To facilitate control of the ratio of the mixed gas formed by hydrogen and flue gas introduced into burner 1 to the primary air, in this embodiment, the boiler combustion system further includes a third pipe 73. One end of the third pipe 73 is connected to the outlet of the gas mixer 3, and the other end is connected to the second gas supply chamber 102. A third control valve 83 is provided on the third pipe 73. In this embodiment, the hydrogen supply subsystem includes a fourth pipe 74 and a hydrogen supply device. One end of the fourth pipe 74 is connected to the hydrogen supply device 9, and the other end is connected to the gas mixer 3. The outlet of the silver powder machine is connected to the gas mixer 3 through a fifth pipe 75. To facilitate adjustment of the mixing ratio of hydrogen and flue gas, in this embodiment, a fourth control valve 84 is provided on the fourth pipe 74, and a fifth control valve 85 is provided on the fifth pipe 75. The first control valve 81, the second control valve 82, the third control valve 83, the fourth control valve 84, and the fifth control valve 85 are all solenoid valves.

[0032] In summary, the boiler combustion system of this utility model includes a burner 1, a boiler 2, a gas mixer 3, a hydrogen supply subsystem, a flue gas supply subsystem, and an air supply subsystem. The burner 1 is connected to the boiler 2 and has a first gas delivery chamber 101 and a second gas delivery chamber 102 that communicate with the furnace cavity of the boiler 2. The air supply subsystem is connected to the first gas delivery chamber 101. The outlet of the hydrogen supply subsystem and the outlet of the flue gas supply subsystem are both connected to the inlet of the gas mixer 3. The outlet of the gas mixer 3 is connected to the second gas delivery chamber 102. Hydrogen and flue gas are premixed in the gas mixer 3 before being fed into the burner 1. The flue gas contains components with strong radiation capabilities such as soot and carbon dioxide. The combustion of flue gas and hydrogen produces a flame with strong radiation capability, which is conducive to the rapid transfer of flame heat and can prevent the heating surface inside the furnace from overheating, thus ensuring the safe operation of the boiler 2.

[0033] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A boiler combustion system, characterized in that, The system includes a burner (1), a boiler (2), a gas mixer (3), a hydrogen supply subsystem, a flue gas supply subsystem, and an air supply subsystem. The burner (1) is connected to the boiler (2) and has a first gas delivery chamber (101) and a second gas delivery chamber (102) that are connected to the furnace chamber of the boiler (2). The air supply subsystem is connected to the first gas delivery chamber (101). The outlet of the hydrogen supply subsystem and the outlet of the flue gas supply subsystem are both connected to the inlet of the gas mixer (3). The outlet of the gas mixer (3) is connected to the second gas delivery chamber (102).

2. The boiler combustion system according to claim 1, characterized in that, The burner (1) also has a third air supply chamber (103). The air supply subsystem includes a primary air supply pipe (76), a secondary air supply pipe (77), and an air supply device. The primary air supply pipe (76) and the secondary air supply pipe (77) are both connected to the air supply device. The end of the primary air supply pipe (76) away from the air supply device is connected to the first air supply chamber (101), and the end of the secondary air supply pipe (77) away from the air supply device is connected to the third air supply chamber (103).

3. The boiler combustion system according to claim 2, characterized in that, The burner (1) includes a central tube (11), a first sleeve (12) sleeved outside the central tube (11), and a second sleeve (13) sleeved outside the first sleeve (12); The lumen of the central tube (11) forms the first gas delivery chamber (101), the structure between the inner wall of the first sleeve (12) and the outer wall of the central tube (11) forms the second gas delivery chamber (102), and the inner wall of the second sleeve (13) and the outer wall of the first sleeve (12) form the third gas delivery chamber (103).

4. The boiler combustion system according to claim 2, characterized in that, The flue gas supply subsystem includes an induced draft fan (41), one end of which is connected to the flue gas pipe of the boiler (2), and the other end is connected to the gas mixer (3).

5. The boiler combustion system according to claim 4, characterized in that, The boiler combustion system also includes an air preheater (5), which has a first heat exchange chamber and a second heat exchange chamber capable of heat exchange. The exhaust pipe, the first heat exchange chamber, the induced draft fan (41) and the gas mixer (3) are connected in sequence; The air supply device includes a first fan (42), the air outlet of the first fan (42) is connected to one end of the third air supply chamber (103), and the end of the primary air supply pipe (76) away from the first air supply chamber (101) and the end of the secondary air supply pipe (77) away from the third air supply chamber (103) are both connected to the other end of the third air supply chamber (103).

6. The boiler combustion system according to claim 5, characterized in that, The air preheater (5) has a third heat exchange chamber that can exchange heat with the first heat exchange chamber. The boiler combustion system includes a second fan (43) and a pulverized coal supply device (6) with a pulverized coal outlet chamber. The second fan (43), the third heat exchange chamber, the pulverized coal outlet chamber and the pulverized coal inlet of the boiler are connected in sequence.

7. The boiler combustion system according to claim 6, characterized in that, The boiler combustion system also includes a first pipe body (71), one end of which is connected to the air outlet of the second fan (43), and the other end is connected to the powder outlet chamber. A first control valve (81) is provided on the first pipe body (71).

8. The boiler combustion system according to claim 7, characterized in that, The boiler combustion system also includes a second tube (72), one end of which is connected to the third heat exchange chamber and the other end is connected to the powder outlet chamber. A second control valve (82) is provided on the second tube (72).

9. The boiler combustion system according to claim 4, characterized in that, The hydrogen supply subsystem includes a hydrogen supply device (9), a fourth pipe (74) and a fourth control valve (84). One end of the fourth pipe (74) is connected to the hydrogen supply device (9), and the other end is connected to the gas mixer (3). The fourth control valve (84) is installed on the fourth pipe (74). The boiler combustion system includes a fifth tube (75) and a fifth control valve (85). One end of the fifth tube (75) is connected to the air outlet of the induced draft fan (41), and the other end is connected to the gas mixer (3). The fifth control valve (85) is installed on the fifth tube (75).

10. The boiler combustion system according to claim 1, characterized in that, The boiler combustion system also includes a third tube (73), one end of which is connected to the gas outlet of the gas mixer (3) and the other end is connected to the second gas delivery chamber (102). A third control valve (83) is provided on the third tube (73).

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