350MW-grade semicoke tail gas efficient supercritical boiler for combustion

Abstract

In order to solve the problems that an existing high-temperature gas boiler is low in gas calorific value, gas fluctuates and large in occupied area, a water cooling wall and an enclosure wall are fixed in a boiler body, an upper-level economizer is installed on the enclosure wall, and the bottom of the upper-level economizer is connected with a lower-level economizer; the bottom of the lower-stage economizer is connected with a rotary air preheater, the upper-stage economizer is connected with a water cooling wall, the water cooling wall is connected with a steam-water separator, the steam-water separator is connected with a roof pipe, a low-temperature superheater is arranged in a rear flue of the enclosure wall and connected with a partition screen, the partition screen is connected with a final-stage superheater, and a low-temperature reheater is installed in a front flue of the enclosure wall. The low-temperature reheater is connected with the final-stage reheater, and the integrated drain flash tank is connected with the bottom of the steam-water separator; the partition screen is hung on the heating surface in the hearth of the boiler body and arranged at the hearth outlet of the boiler body, the combustor is arranged below the water cooling wall in the boiler body, and the overall occupied area of the boiler is reduced.

Description

Technical Field

[0001] The patent of this invention belongs to the field of electric power and thermal energy technology, and relates to a 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas. Background Art

[0002] The efficient use of energy has always been a long-term concern in the field of power and thermal energy. With the layout and promotion of a large number of lignite semi-coke coal chemical industries in Hami Industrial Park in Xinjiang, the output of lignite semi-coke gas has also grown rapidly. In addition, with the increase in resource consumption and the emphasis on environmental protection in my country, the efficient use of semi-coke gas has received more and more attention from enterprises. The development of 350MW high-efficiency supercritical boilers burning lignite semi-coke gas can achieve safe and efficient use of semi-coke gas, which has the advantages of relatively low investment and short recovery period. It can not only bring good economic benefits to enterprises, but also generate good social benefits, and has high promotion and application value.

[0003] At present, existing high-temperature gas boilers have problems such as low gas calorific value, gas fluctuations, and large floor space. Summary of the invention

[0004] The purpose of the patent of this invention: The invention is to solve the problems of low gas calorific value, gas fluctuation and large floor space in existing high-temperature gas boilers. The invention provides a 350MW grade high-efficiency supercritical boiler burning semi-coke tail gas.

[0005] The object of the present invention is achieved as follows: a 350MW grade semi-coke tail gas burning high-efficiency supercritical boiler, which includes a furnace body, a water-cooled wall, a partition screen, a wall, a final superheater, a final reheater, a low-temperature reheater, a low-temperature superheater, an upper economizer, a lower economizer, a rotary air preheater, a burner, a ceiling pipe, an integrated drain expansion tank, and a steam-water separator;

[0006] The water-cooled wall and the wrapping wall are fixed in the furnace body, the upper economizer is installed on the wrapping wall, the outlet of the upper economizer is reserved with SCR denitration space, the bottom of the upper economizer is connected to the lower economizer, the bottom of the lower economizer is connected to the rotary air preheater, and the upper economizer is connected to the water-cooled wall.

[0007] The water-cooled wall is connected to the steam-water separator, which is connected to the ceiling pipe. The rear flue of the wall is equipped with a low-temperature superheater, which is connected to the partition screen, which is connected to the final superheater. The front flue of the wall is equipped with a low-temperature reheater, which is connected to the final reheater. The integrated drain expansion tank is connected to the bottom of the steam-water separator.

[0008] The partition screen is hung on the heating surface inside the furnace of the furnace body and arranged at the furnace outlet of the furnace body. The burner is arranged below the water-cooled wall inside the furnace body.

[0009] Furthermore, the heating surfaces of the low-temperature reheater and the low-temperature superheater are arranged horizontally.

[0010] Furthermore, the heating surfaces of the partition screen, the final superheater and the final reheater are arranged vertically.

[0011] Furthermore, the integrated hydrophobic expansion container is arranged in the upper span of the furnace body.

[0012] Furthermore, a primary desuperheater is provided between the low-temperature superheater and the partition screen.

[0013] Furthermore, a secondary superheater is arranged between the partition screen and the final superheater.

[0014] Furthermore, the burner is a double swirl low NOx burner.

[0015] Furthermore, the lower side of the water-cooled wall and the boiler ash hopper of the furnace body are both spiral tube coil water-cooled walls.

[0016] Furthermore, the upper side of the water-cooled wall is a vertical tube panel water-cooled wall.

[0017] Beneficial effects:

[0018] 1. This scheme provides a 350MW high-efficiency supercritical boiler with variable pressure operation, one-stage intermediate reheating, single furnace, balanced ventilation, all-steel frame suspension structure, open-air layout, and burning semi-coke tail gas;

[0019] 2. The steam temperature of the outlet superheater and reheater of the patented boiler of this invention is different from the traditional supercritical 571℃ and 569℃, reaching 605℃ and 603℃ respectively, which further improves the unit efficiency;

[0020] 3. The high-temperature and high-pressure water vapor of the present invention is efficiently converted into electrical energy through the steam turbine generator set, thereby completing the efficient conversion of fuel combustion heat into electrical energy;

[0021] 4. The internal structure of the present invention is reasonably distributed and compact, the furnace size and burnout height are reasonably selected, which saves space. In view of the low calorific value of semi-coke tail gas, the heat absorption of the heated surface is enhanced, the heat absorption of the furnace body is weakened, and the low-temperature reheater participates in temperature regulation, which can meet the design parameters of reheat steam at a lower load;

[0022] 5. The patent of this invention adopts the left and right wall counter-combustion mode, and sets the ember burning wind at the same time. The burners are arranged on the left and right walls, the resistance along the air ducts on both sides is similar, the air distribution is uniform, and the NOx emission is low. At the same time, the burners are arranged on the left and right walls, which reserves enough space for the air preheater behind the furnace, and the overall footprint of the boiler is reduced;

[0023] 6. The low-temperature superheater and low-temperature reheater of the present invention adopt a new design, which increases the heating surface in the rear flue turning chamber, thereby increasing the layout height of the rear flue heating surface, leaving enough layout space for the denitrification device and air preheater, and reducing the overall footprint of the boiler;

[0024] 7. The economizer of the present invention adopts a hierarchical arrangement in which the lower economizer is connected to the bottom of the upper economizer to ensure that the flue gas temperature at the denitrification inlet meets the operation requirements at a low load;

[0025] 8. The patent of this invention applies the two-compartment rotary air preheater to the semi-coke tail gas boiler for the first time, which has strong anti-ash blocking and anti-corrosion capabilities, saves space, and is conducive to flue layout;

[0026] 9. The lower furnace water-cooled wall and ash hopper of the present invention adopt spiral tube rings, which have a higher mass flow rate, have sufficient cooling capacity under various loads, and can effectively compensate for the thermal deviation along the furnace perimeter. The hydrodynamic characteristics are stable and suitable for the fluctuating working conditions of coal gas in coking enterprises;

[0027] 10. The patent of this invention adopts an integrated steam-water separator water storage tank to save space. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of a 350MW class high efficiency supercritical boiler burning semi-coke tail gas. DETAILED DESCRIPTION

[0029] Specific implementation method 1: A 350MW-class semi-coke tail gas-fired high-efficiency supercritical boiler, which includes a furnace body 1, a water-cooled wall 2, a partition screen 3, a wall 4, a final superheater 5, a final reheater 6, a low-temperature reheater 7, a low-temperature superheater 8, an upper economizer 9, a lower economizer 10, a rotary air preheater 11, a burner 12, a ceiling pipe 13, an integrated drain expansion tank 14, and a steam-water separator 15;

[0030] The water-cooled wall 2 and the wrapping wall 4 are fixed in the furnace body 1, the upper economizer 9 is installed on the wrapping wall 4, the outlet of the upper economizer 9 is reserved with SCR denitration space, the bottom of the upper economizer 9 is connected to the lower economizer 10, the bottom of the lower economizer 10 is connected to the rotary air preheater 11, and the upper economizer 9 is connected to the water-cooled wall 2.

[0031] The water-cooled wall 2 is connected to the steam-water separator 15, the steam-water separator 15 is connected to the ceiling pipe 13, the low-temperature superheater 8 is arranged in the rear flue of the wall 4, the low-temperature superheater 3 is connected to the partition screen 3, the partition screen 3 is connected to the final superheater 5, the front flue of the wall 4 is installed with the low-temperature reheater 7, the low-temperature reheater 7 is connected to the final reheater 6, and the integrated drain expansion tank 14 is connected to the bottom of the steam-water separator 15;

[0032] The partition screen 3 is suspended on the heating surface inside the furnace of the furnace body 1 and arranged at the furnace outlet of the furnace body 1 . The burner 12 is arranged below the water-cooled wall 2 inside the furnace body 1 .

[0033] Specific implementation method 2: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, the heating surfaces of the low-temperature reheater 7 and the low-temperature superheater 8 are arranged horizontally.

[0034] Other implementations are the same as the first specific implementation.

[0035] Specific implementation method three: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, wherein the heating surfaces of the partition screen 3, the final superheater 5 and the final reheater 6 are arranged vertically.

[0036] Other implementations are the same as the first specific implementation.

[0037] Specific implementation method 4: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, wherein the integrated drain expansion container 14 is arranged in the upper span of the furnace body 1 .

[0038] Other implementations are the same as the first specific implementation.

[0039] Specific implementation method five: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, wherein a primary desuperheater is arranged between the low-temperature superheater 8 and the partition screen 3.

[0040] Other implementations are the same as the first specific implementation.

[0041] Specific implementation method six: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, wherein a secondary superheater is arranged between the partition screen 3 and the final superheater 5 .

[0042] Other implementations are the same as the first specific implementation.

[0043] Specific implementation method seven: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, wherein the burner 12 is a double-swirl low NOx burner.

[0044] Other implementations are the same as the first specific implementation.

[0045] Specific implementation method eight: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, wherein the lower side of the water-cooled wall 2 and the boiler ash hopper of the furnace body 1 are both spiral tube ring water-cooled walls.

[0046] Other implementations are the same as the first specific implementation.

[0047] Specific implementation method 9: A 350MW-class high-efficiency supercritical boiler burning semi-coke tail gas, the upper side of the water-cooled wall 2 is a vertical tube panel water-cooled wall.

[0048] Other implementations are the same as the first specific implementation.

[0049] Example

[0050] A water-cooled wall 2 and a wrapping wall 4 are fixedly installed in the furnace body 1. An upper economizer 9 is installed on the wrapping wall 4. An SCR denitration space is reserved at the outlet of the upper economizer 9. The economizer adopts a hierarchical arrangement form in which the lower economizer 10 is connected to the bottom of the upper economizer 9 to ensure that the flue gas temperature at the denitration inlet meets the operation requirements at a low load. The upper economizer 9 and the lower economizer 10 are both suspended and fixed; a rotary air preheater 11 is installed at the bottom of the lower economizer 10, and the upper economizer 9 is connected to the water-cooled wall 2;

[0051] The water-cooled wall 2 is connected to a steam-water separator 15, which is connected to the ceiling pipe 13. The superheater system adopts a three-stage arrangement, that is, the rear flue of the wall 4 is arranged with a low-temperature superheater 8, which adopts a hanging and fixing structure, and the low-temperature superheater 8 is connected to the partition screen 3, and the partition screen 3 is connected to the final superheater 5; the reheater adopts a two-stage arrangement, that is, the front flue of the wall 4 is installed with a low-temperature reheater 7, which adopts a hanging and fixing structure, and the low-temperature reheater 7 is connected to the final reheater 6. The heating surfaces of the low-temperature reheater 7 and the low-temperature superheater 8 are arranged horizontally, and the heating surfaces of the partition screen 3, the final superheater 5, and the final reheater 6 are arranged vertically. The integrated hydrophobic expansion tank 14 is connected to the bottom of the steam-water separator 15, and the integrated hydrophobic expansion tank 14 is arranged in the upper span of the furnace body 1.

[0052] The partition screen 3 suspends the heating surface inside the furnace of the furnace body 1 and is arranged at the furnace outlet of the furnace body 1 . A burner 12 is arranged in the furnace body 1 below the water-cooled wall 2 .

[0053] The superheated steam temperature is controlled by gas-water ratio and two-stage water spray cooling, that is, a first-stage cooler is arranged between the low-temperature superheater 8 and the partition screen 3, and a second-stage superheater is arranged between the partition screen 3 and the final superheater 5.

[0054] The burner 12 is a double swirl low NOx burner, and the left and right walls of the double swirl low NOx burner are arranged opposite each other, so that the temperature field in the furnace body 1 is uniform, which can effectively shorten the layout length of the hot air duct and effectively reduce the depth of the boiler.

[0055] The lower side of the water-cooled wall 2 and the boiler cold ash hopper of the furnace body 1 are both spiral tube ring water-cooled walls, and the upper side of the water-cooled wall 2 is a vertical tube panel water-cooled wall. The spiral tube ring water-cooled wall and the vertical tube panel water-cooled wall are connected through a transition header. The spiral tube ring water-cooled wall adopts an expandable vertical rigid beam system with a tension plate. The suspension of the spiral tube ring of the spiral tube ring water-cooled wall is realized by a tension plate evenly attached to the outer surface of the tube wall; the tension plate is arranged from the bottom of the furnace cold ash hopper to the transition zone between the spiral tube ring and the vertical tube panel water-cooled wall, and the weight load is evenly transferred to the upper vertical tube panel of the vertical tube panel water-cooled wall through the comb-shaped hanging plate in the transition zone; the self-weight load of the rigid beam system and the furnace wall is completely supported by the vertical lap plate, and the load of the lower furnace of the furnace body 1 and the boiler cold ash hopper can be transferred to the vertical tube panel water-cooled wall.

[0056] The integrated dredging and expansion system 14 is a startup system, which adopts an atmospheric expansion tank type, and the system is simple and easy to maintain; the atmospheric expansion tank and the small drain header adopt an integrated design to realize the boiler span arrangement of the integrated dredging and expansion system 14.

[0057] The tubes in the same tube band of the spiral tube coil water-cooled wall bypass the corners and middle parts of the furnace in the furnace body 1 from bottom to top in the same way. It has strong applicability and sufficient cooling capacity under various loads. Since it can effectively compensate for thermal deviations along the circumference of the furnace, the hydrodynamic characteristics are stable.

[0058] Here’s how it works:

[0059] This embodiment mainly transfers the combustion heat of the fuel to the energy transfer medium inside the heating surface through the internal heating surface of the furnace body 1. The energy transfer medium can be water or water vapor. The high-temperature and high-pressure water vapor is efficiently converted into electrical energy through the steam turbine generator set, thereby completing the efficient conversion of the fuel combustion heat into electrical energy.

[0060] On the flue gas side, the fuel and the high-temperature air at the outlet of the rotary air preheater 11 are burned in the furnace body 1, pass through the heating surfaces of each level in the furnace body 1 in sequence, and are finally discharged through the air preheater.

[0061] The primary steam, i.e. the superheated steam side, passes through the lower economizer 10, the upper economizer 9, the water-cooled wall 2, the steam-water separator 15, the enclosure wall 4, the low-temperature superheater 8, the partition screen 3, the final superheater 5, and finally enters the high-pressure cylinder of the steam turbine through the main steam pipeline to generate electricity.

[0062] On the secondary steam side, that is, the reheated steam side, the exhaust steam from the high-pressure cylinder passes through the cold reheat pipe and enters the low-temperature reheater 7 and the final reheater 6 in sequence, and then enters the turbine intermediate-pressure cylinder through the hot reheat pipe to generate electricity.

Claims

1. A 350MW class high efficiency supercritical boiler burning semi-coke tail gas, characterized by: It comprises a furnace body (1), a water-cooled wall (2), a partition screen (3), a wrapping wall (4), a final superheater (5), a final reheater (6), a low-temperature reheater (7), a low-temperature superheater (8), an upper economizer (9), a lower economizer (10), a rotary air preheater (11), a burner (12), a ceiling pipe (13), an integrated drain expansion tank (14), and a steam-water separator (15); The water-cooled wall (2) and the enclosing wall (4) are fixed in the furnace body (1), the upper economizer (9) is installed on the enclosing wall (4), an SCR denitration space is reserved at the outlet of the upper economizer (9), the bottom of the upper economizer (9) is connected to the lower economizer (10), the bottom of the lower economizer (10) is connected to the rotary air preheater (11), the upper economizer (9) is connected to the water-cooled wall (2), The water-cooled wall (2) is connected to a steam-water separator (15), the steam-water separator (15) is connected to a ceiling pipe (13), a low-temperature superheater (8) is arranged in the rear flue of the enclosure wall (4), the low-temperature superheater (3) is connected to a partition screen (3), the partition screen (3) is connected to a final superheater (5), a low-temperature reheater (7) is installed in the front flue of the enclosure wall (4), the low-temperature reheater (7) is connected to a final reheater (6), and an integrated drain expansion tank (14) is connected to the bottom of the steam-water separator (15); The partition screen (3) is suspended on the heating surface inside the furnace of the furnace body (1) and arranged at the furnace outlet of the furnace body (1). The burner (12) is arranged below the water-cooled wall (2) inside the furnace body (1).

2. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: The heating surfaces of the low-temperature reheater (7) and the low-temperature superheater (8) are arranged horizontally.

3. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: The heating surfaces of the partition screen (3), the final stage superheater (5) and the final stage reheater (6) are arranged vertically.

4. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: The integrated hydrophobic expansion container (14) is arranged inside the upper span of the furnace body (1).

5. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: A primary desuperheater is provided between the low-temperature superheater (8) and the partition screen (3).

6. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: A secondary superheater is arranged between the partition screen (3) and the final superheater (5).

7. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: The burner (12) is a double swirl low NOx burner.

8. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: The lower side of the water-cooled wall (2) and the boiler ash hopper of the furnace body (1) are both spiral tube coil water-cooled walls.

9. A 350MW grade semi-coke tail gas burning high efficiency supercritical boiler according to claim 1, characterized in that: The upper side of the water-cooled wall (2) is a vertical tube panel water-cooled wall.

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