A liquid slagging boiler of opposed firing type

Abstract

The embodiment of the present application provides a liquid slagging boiler of opposed firing mode, which comprises a boiler body and a burner, the boiler body is internally provided with a hearth and a molten slag combustion chamber, the outlet of the molten slag combustion chamber is communicated with the hearth, the molten slag combustion chamber comprises a first molten slag combustion chamber and a second molten slag combustion chamber, the first molten slag combustion chamber is located at one side of the hearth, the second molten slag combustion chamber is located at the other side of the hearth, and the outlet of the first molten slag combustion chamber and the outlet of the second molten slag combustion chamber are oppositely arranged, and the burner is connected with the boiler body so that the outlet of the burner is communicated with the inlet of the molten slag combustion chamber. The liquid slagging boiler of opposed firing mode has the advantages that slagging and heating surface contamination are not prone to occur in the boiler body, and the ash content of flue gas is low.

Description

Technical Field

[0001] This invention relates to the field of combustion boiler technology, and more specifically to a liquid ash discharge boiler with a counter-current combustion method. Background Technology

[0002] A liquid slag boiler is a boiler in which the slag generated after fuel combustion is melted into a liquid state at high temperature in the slag chamber and discharged from the furnace.

[0003] In related technologies, the slag chamber and burner of a liquid slag discharge boiler are arranged vertically. In other words, the slag chamber is located directly below the burner, and the burner and slag chamber are arranged horizontally alongside the furnace cavity of the boiler body. The burner outlet is connected to both the slag chamber and the furnace cavity. This arrangement of liquid slag discharge boilers results in incomplete combustion, with a large amount of ash and slag in the flame and flue gas, leading to slagging and fouling of the boiler body and heating surfaces. Furthermore, the presence of a large amount of ash and slag in the flue gas can cause blockage of the annular and even heating surface flue gas passages. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a liquid ash discharge boiler with a counter-firing combustion method. This counter-firing combustion method liquid ash discharge boiler has the advantages of being less prone to slagging within the boiler body and fouling of the heating surfaces, and having a low ash content in the flue gas.

[0005] The liquid ash discharge boiler with counter-firing combustion method according to embodiments of the present invention includes:

[0006] The boiler body includes a furnace and a slag combustion chamber. The slag combustion chamber has an inlet and an outlet. The outlet of the slag combustion chamber is connected to the furnace. The slag combustion chamber includes a first slag combustion chamber and a second slag combustion chamber. The first slag combustion chamber is located on one side of the furnace, and the second slag combustion chamber is located on the other side of the furnace. The outlets of the first slag combustion chamber and the second slag combustion chamber are arranged opposite to each other.

[0007] A burner is connected to the boiler body such that the outlet of the burner is connected to the inlet of the slag combustion chamber.

[0008] In the liquid ash discharge boiler with counter-firing combustion method according to this invention embodiment, after the coal, especially high-alkali coal, is ignited and burned in the burner, it enters the molten slag combustion chamber. In the molten slag combustion chamber, it undergoes intense combustion via liquid slag film combustion. Within the molten slag combustion chamber, alkali metals undergo a series of physicochemical reactions with the liquid ash to solidify and capture a certain proportion of alkali metals, thereby significantly reducing the alkali metal content and ash content in the high-temperature flame. Then, the coal flame passes through the molten slag combustion chamber and enters the furnace for counter-firing and combustion. Because the coal flame needs to pass through the molten slag combustion chamber, the capturing effect of the molten slag combustion chamber can better act on the coal, effectively removing the ash components. Simultaneously, the unburned coal particles and combustible gases discharged from the molten slag combustion chamber undergo intense mixing and turbulent disturbance during the counter-firing and collision within the furnace, ensuring complete combustion of the coal. Therefore, slagging and fouling of the heating surfaces are less likely to occur within the boiler body, and the ash mineral content in the flue gas, which is prone to fouling the wastewater walls and heating surfaces, is significantly reduced.

[0009] In some embodiments, the furnace extends vertically, a first slag combustion chamber is provided on one side of the furnace in a first direction, and a second slag combustion chamber is provided on the other side of the furnace in the first direction. The first direction is orthogonal to the vertical direction, the slag combustion chambers extend along the first direction, and the opening directions of the outlet and inlet of the slag combustion chambers are both parallel to the first direction, and the opening directions of the outlet and inlet of the slag combustion chambers are opposite; and / or

[0010] The burner is a cyclone burner.

[0011] In some embodiments, the furnace includes a lower furnace and an upper furnace, the lower furnace is connected to the upper furnace and located below the upper furnace, the outlet of the slag combustion chamber is connected to the lower furnace, the boiler body has a recessed portion, the recessed portion surrounds the boiler body around its central axis, and the recessed portion is located at the connection point between the lower furnace and the upper furnace.

[0012] In some embodiments, the liquid slag discharge boiler with counter-firing combustion further includes a slag collection device, which is connected to the boiler body and located at the outlet of the molten slag combustion chamber.

[0013] In some embodiments, the slag-collecting device includes a slag-collecting tube bundle, which comprises a plurality of parallel and spaced-apart slag-collecting tubes, the interior of which contains a cooling medium.

[0014] In some embodiments, the extension direction of the slag-collecting tube bundle has an inclination angle between the vertical direction and the vertical direction, and the inclination angle is less than 30°.

[0015] In some embodiments, the liquid slag discharge boiler with counter-firing combustion further includes a liquid slag hopper and a water tank. The liquid slag hopper has an inlet and an outlet. The liquid slag hopper is connected to the boiler body so that the molten slag combustion chamber is connected to the inlet of the liquid slag hopper. One end of the slag collection device is disposed on the inner circumferential surface of the liquid slag hopper, and the outlet of the liquid slag hopper is connected to the water tank.

[0016] In some embodiments, the liquid ash discharge boiler with counter-firing combustion further includes an ash removal machine connected to the water tank to remove ash particles from the water tank.

[0017] In some embodiments, the bottom of the boiler body has a dry slag hopper, the internal space of which is in communication with the furnace.

[0018] In some embodiments, the liquid ash discharge boiler with counter-firing combustion further includes a soot blower and / or a burnout air device, the boiler body includes a membrane water-cooled wall surrounding the furnace, and the membrane water-cooled wall is provided with a first opening and / or a second opening communicating with the furnace.

[0019] The soot blower includes a steam nozzle, a steam pipe, and a telescopic mechanism. The telescopic mechanism is located on the outer wall of the membrane water-cooled wall. The telescopic mechanism is equipped with the steam nozzle, and the telescopic mechanism drives the steam nozzle to enter or exit the furnace through the first opening. The steam nozzle is connected to the steam pipe.

[0020] The burnout air device is located on the outer wall surface of the membrane water-cooled wall, and the air outlet of the burnout air device is located in the second opening. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a liquid slag discharge boiler with counter-firing combustion method according to an embodiment of the present invention;

[0022] Figure 2 yes Figure 1 A schematic diagram of the arrangement of the molten slag combustion chamber.

[0023] Figure label:

[0024] 1. Boiler body; 101. Furnace; 1011. Lower furnace; 1012. Upper furnace; 102. First slag combustion chamber; 103. Second slag combustion chamber; 104. Recess; 105. Dry slag hopper; 106. Flue gas passage; 2. Burner; 3. Slag collection device; 4. Liquid slag hopper; 5. Water tank; 6. Slag remover; 7. Soot blower; 8. Burnout air device; 9. Screen-type heating surface; 901. Front screen superheater; 902. Rear screen superheater; 903. High-temperature superheater; 904. High-temperature reheater; 905. Low-temperature reheater; 11. Economizer; 12. Air preheater; 13. Slag well. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following is a reference appendix. Figure 1 -Appendix Figure 2 A liquid ash discharge boiler with a counter-firing combustion method according to an embodiment of the present invention is described.

[0027] like Figure 1 and Figure 2 As shown, the liquid slag discharge boiler with counter-firing combustion method according to an embodiment of the present invention includes a boiler body 1 and a burner 2.

[0028] The boiler body 1 is equipped with a furnace 101 and a slag combustion chamber. The slag combustion chamber has an inlet and an outlet. The outlet of the slag combustion chamber is connected to the furnace 101. The coal is ignited and burned in the cyclone burner 2 and the slag combustion chamber 102. Under the capture effect of the slag combustion chamber 102, most of the ash and slag components are removed. The coal flame with most of the ash and slag components removed enters the furnace 101 through the outlet of the slag combustion chamber. Then the pulverized coal is burned out in the furnace 101.

[0029] The slag combustion chamber includes a first slag combustion chamber 102 and a second slag combustion chamber 103. The first slag combustion chamber 102 is located on one side of the furnace 101, and the second slag combustion chamber 103 is located on the other side of the furnace 101. The outlets of the first slag combustion chamber 102 and the second slag combustion chamber 103 are arranged opposite to each other. Specifically, as shown... Figure 1As shown, the first slag combustion chamber 102 is located on the left side of the furnace 101, and the outlet of the first slag combustion chamber 102 opens to the right. The second slag combustion chamber 103 is located on the right side of the furnace 101, and the outlet of the second slag combustion chamber 103 opens to the left. The coal particles and flames discharged from the first slag combustion chamber 102 and the second slag combustion chamber 103 collide and impact each other in the furnace 101, thereby producing a violent and uniform mixture and causing the coal particles to burn violently and completely. The flue gas velocity after combustion is uniform, so that the heat exchange surface in the furnace 101 will not have deviations in flue gas temperature and air temperature due to non-uniform velocity field, non-uniform flow and non-uniform temperature. Preferably, the outlet temperature of the slag combustion chamber 102 is 1500℃~1600℃.

[0030] The burner 2 is connected to the boiler body 1 so that the outlet of the burner 2 is connected to the inlet of the molten slag combustion chamber. The burner 2 ignites and burns the coal, and through the dynamic field characteristics of the burner 2, the coal flame has sufficient jet rigidity to ensure that the coal flame can pass through the molten slag combustion chamber and be injected into the furnace 101.

[0031] In related technologies, the slag chamber and burner of a liquid slag discharge boiler are arranged vertically. In other words, the slag chamber is located directly below the burner, and the burner and slag chamber are arranged horizontally alongside the furnace cavity of the boiler body. The burner outlet is connected to both the slag chamber and the furnace cavity. After being ignited in the burner, pulverized coal moves downward into the slag chamber, where it briefly stays to separate and remove ash and slag before moving upward and turning to enter the furnace cavity for complete combustion, thereby generating heat.

[0032] However, the inventors discovered that conventional liquid ash discharge boilers in related technologies are prone to slagging and fouling of heating surfaces when burning high-alkali coal. Furthermore, the flue gas contains high concentrations of alkali metals and ash, which can clog the flue gas passages between the boiler's water-cooled walls and screen-type heating surfaces. To prevent ash from high-alkali coal from causing boiler slagging and fouling of heating surfaces, and even heat exchange obstacles and flue blockages that could jeopardize the normal operation of the boiler, it is necessary to regularly clean the boiler body and flue gas passages to maintain normal boiler operation.

[0033] Through in-depth research, the inventors discovered that both liquid ash discharge boilers and solid ash discharge pulverized coal boilers of related technologies suffer from insufficient adaptability when burning high-alkali coal. These include defects in conventional liquid ash discharge boilers such as excessively short distances between the heating surfaces and high-temperature flue gas, insufficient alkali metal capture capacity, weak furnace anti-fouling ability, and inadequate air staging, resulting in low burnout rates. Furthermore, conventional solid ash discharge pulverized coal boilers exhibit insufficient alkali metal capture capacity, high ash content in the flue gas, and problems such as slagging in the furnace and heating surfaces, heating surface fouling, and flue gas passage blockage, all of which endanger boiler operational safety. The reason lies in the fact that neither type of boiler is adequately designed according to the coal quality characteristics of high-alkali coal, and therefore cannot fully meet the requirements for safe, clean, and efficient combustion of high-alkali coal.

[0034] To this end, the inventors have proposed a liquid ash discharge boiler with a counter-firing combustion method. In the liquid ash discharge boiler with a counter-firing combustion method according to the embodiments of the present invention, after the high-alkali coal is ignited by the burner, it first burns in the molten slag combustion chamber and solidifies and captures the alkali metals, so as to intercept most of the ash components in the form of liquid slag outside the furnace. The coal flame with a lower ash content passes through the molten slag combustion chamber and enters the furnace to counter-fire and burn out in the furnace. Because high-alkali coal ignites and burns in the burner and molten slag combustion chamber under a liquid slag film environment, the combustion environment of the liquid slag film solidifies and captures alkali metals through physicochemical reactions. Therefore, the molten slag combustion chamber can better capture alkali metals and ash on high-alkali coal, thereby effectively removing alkali metals and ash components from high-alkali coal. At the same time, the coal flame with lower alkali metal and ash content discharged from the molten slag combustion chamber can cause the coal particles and other combustible components in the flue gas to mix violently and burn completely due to the collision and impact in the furnace. Therefore, slagging and fouling of the heating surface are less likely to occur in the boiler body, so as to achieve a low nitrogen oxide combustion mode and thus make the flue gas cleaner.

[0035] It should be noted that high-alkali coal refers to coal with an alkali metal content greater than 4%. Due to this alkali metal content, high-alkali coal has serious problems that endanger boiler operation safety, such as low ash melting point, strong slagging and fouling, and easy ash blockage in the tail flue. Therefore, liquid ash discharge boilers and conventional solid ash discharge boilers in related technologies suffer from severe slagging, heating surface fouling, and flue gas passage blockage when burning high-alkali coal, even leading to operational safety hazards. However, the liquid ash discharge boiler with counter-firing combustion method of this invention can fully capture and discharge alkali metals and ash components in the early stage of combustion, thus reducing the likelihood of slagging, heating surface fouling, and flue gas passage blockage when burning high-alkali coal. In addition to being suitable for high-alkali coal with an alkali metal content greater than 4%, the liquid ash discharge boiler with counter-firing combustion method of this invention is also suitable for ordinary pulverized coal with an alkali metal content less than 2%.

[0036] Meanwhile, the liquid slag discharge boiler with counter-firing combustion method of the present invention also has the advantage of being easy to manufacture. The liquid slag discharge boiler with counter-firing combustion method of the present invention can be obtained by modifying the solid slag discharge boiler of the related technology. Specifically, a first molten slag combustion chamber and a second molten slag combustion chamber are set on both sides of the pulverized coal boiler, and the first molten slag combustion chamber and the second molten slag combustion chamber are connected to the furnace of the solid slag discharge boiler. The solid slag discharge boiler of the related technology can be modified into the liquid slag discharge boiler with counter-firing combustion method of the present invention. In this way, the alkali metal is first captured and solidified by the physicochemical reaction of the mineral at high temperature through the liquid slag discharge combustion method. Then, the ash and slag are captured and discharged through the molten slag combustion chamber, which greatly reduces the ash and slag content in the flue gas entering the later furnace. Then, the high furnace design of the solid slag discharge boiler can fully cool the high temperature flue gas and discharge the dry slag that is condensed in the later stage into the furnace through the dry slag discharge method.

[0037] In some embodiments, the furnace chamber 101 extends in a vertical direction, and the furnace chamber 101 in a first direction (e.g., Figure 1 A first slag combustion chamber 102 is provided on one side of the furnace 101 in the left-right direction (as shown), and a second slag combustion chamber 103 is provided on the other side of the furnace 101 in the first direction. The first direction is orthogonal to the up-down direction. The slag combustion chamber extends along the first direction. The opening direction of the outlet and the opening direction of the inlet of the slag combustion chamber are both parallel to the first direction, and the opening direction of the outlet and the opening direction of the inlet of the slag combustion chamber are opposite.

[0038] like Figure 2 As shown, four first slag combustion chambers 102 are arranged side by side on the left side of the furnace 101. The left side of the first slag combustion chamber 102 is provided with an inlet that connects to the corresponding burner 2, and the right side of the first slag combustion chamber 102 is provided with an outlet that connects to the furnace 101. The flame and pulverized coal discharged from the burner 2 move to the right in the left-right direction and enter the furnace 101 after passing through the first slag combustion chamber 102.

[0039] Four second slag combustion chambers 103 are arranged side by side on the right side of the furnace 101. The right side of the second slag combustion chamber 103 is provided with an inlet that connects to the corresponding burner 2. The left side of the second slag combustion chamber 103 is provided with an outlet that connects to the furnace 101. The flame and pulverized coal discharged from the burner 2 move to the left in the left-right direction and enter the furnace 101 after passing through the second slag combustion chamber 103.

[0040] The distance between the outlet of the first slag combustion chamber 102 and the outlet of the second slag combustion chamber 103 is preferably 2m-4m, so as to ensure that there is sufficient combustion space in the furnace 101, and to meet the requirements of sufficient combustion time and relatively stable temperature environment for pulverized coal.

[0041] Because the molten slag combustion chamber extends horizontally, and the coal flame discharged from the burner must pass through the molten slag combustion chamber horizontally to enter the furnace, the residence time and movement path of the gas flame and coal particles within the molten slag combustion chamber are relatively long. In the liquid molten slag combustion environment, this facilitates the capture and solidification of alkali metals. The alkali metal and ash capture effect of the molten slag combustion chamber can fully act on the coal flame, causing most of the alkali metals and ash components in high-alkali coal to form liquid slag and be discharged, effectively reducing the alkali metal and ash content entering the furnace. When the pulverized coal is high-alkali coal, more than 50% of the alkali metals in the high-alkali coal are captured in the molten slag combustion chamber and then discharged as liquid slag, thereby reducing the alkali metal content entering the furnace and avoiding slagging, heating surface fouling, and flue gas passage blockage.

[0042] It is understood that the slag combustion chambers are not limited to being located on the left and right sides of the furnace. In other embodiments, slag combustion chambers are provided in all four directions of the furnace: left, right, front, and back. The slag combustion chambers in the left and right directions are arranged opposite each other, and the slag combustion chambers in the front and back directions are arranged opposite each other.

[0043] It is understandable that the number of the first slag combustion chamber and the second slag combustion chamber is not limited, and the number of the first slag combustion chamber and the second slag combustion chamber can be arbitrary.

[0044] It is understood that the extension direction of the slag combustion chamber is not limited to being orthogonal to the vertical direction. In other embodiments, due to construction or installation reasons, the extension direction of the slag combustion chamber has a small angle with the horizontal direction.

[0045] In some embodiments, burner 2 is a cyclone burner.

[0046] Compared to other types of burners, cyclone burners can create a stronger liquid slag film combustion environment in the molten slag combustion chamber. On the one hand, this can enhance the slag combustion chamber's ability to capture ash components and alkali metals, and on the other hand, it can modify the ash during coal combustion into coal ash with a lower tendency to contaminate.

[0047] In some embodiments, the furnace 101 includes a lower furnace 1011 and an upper furnace 1012. The lower furnace 1011 communicates with the upper furnace 1012 and is located below the upper furnace 1012. The outlet of the slag combustion chamber communicates with the lower furnace 1011. The boiler body 1 has a recess 104. The recess 104 surrounds the boiler body 1 around its central axis and is located at the communication position between the lower furnace 1011 and the upper furnace 1012.

[0048] like Figure 1As shown, the left side of the lower furnace 1011 is connected to the first slag combustion chamber 102, the right side of the lower furnace 1011 is connected to the second slag combustion chamber 103, and the top of the lower furnace 1011 is connected to the upper furnace 1012. The temperature inside the lower furnace 1011 is 1400℃-1700℃. The flames and unburned pulverized coal discharged from the first and second slag combustion chambers collide and mix thoroughly in the lower furnace, causing the pulverized coal to burn completely in the lower furnace. The heat from the combustion of the pulverized coal moves upward and is fully exchanged in the upper furnace.

[0049] The recess 104 is annular on the boiler body 1, forming a contraction at the connection point between the lower furnace 1011 and the upper furnace 1012. Flames, unburned coal particles, and ash produced during combustion near the wall of the boiler body 1 are pressed into the lower furnace or pushed towards the center of the furnace by the recess, thereby significantly reducing slagging and fouling of the heating surfaces in the upper furnace, and also preventing the water-cooled walls in the upper furnace from being impacted by the flame.

[0050] The upper furnace 1012 is higher than the lower furnace 1011, and the top of the upper furnace 1012 is provided with a multi-stage screen-type heating surface. The higher space of the upper furnace 1012 allows the heat generated by the combustion of pulverized coal to be reduced to 800℃-900℃ when it moves to the bottom of the screen-type heating surface, thereby avoiding slagging and fouling of the screen-type heating surface, and also preventing the blockage of the flue gas passage below.

[0051] It is understood that in some other embodiments, the boiler body may not have a recessed portion, and the boiler body may be a straight cylindrical shape extending in the vertical direction.

[0052] In some embodiments, the liquid slag discharge boiler of the counter-firing combustion method of the present invention further includes a slag collection device 3, which is connected to the boiler body 1 and located at the outlet of the molten slag combustion chamber.

[0053] The slag trap collects the flame and pulverized coal that are about to be discharged from the molten slag combustion chamber, so that more impurities in the pulverized coal remain in the molten slag combustion chamber and are then collected by the liquid slag hopper.

[0054] In some embodiments, the slag-collecting device 3 includes a slag-collecting tube bundle, which includes a plurality of parallel and spaced-apart slag-collecting tubes, and the interior of the slag-collecting tubes contains a cooling medium.

[0055] like Figure 1As shown, the slag-collecting tube bundle is located at the outlet of the molten slag combustion chamber and extends vertically. The spacing between adjacent slag-collecting tubes is preferably 1-3 times the diameter of the slag-collecting tube. Circulating cooling water is installed inside the slag-collecting tubes to maintain the temperature of the outer circumference of the tubes. The flame and pulverized coal in the molten slag combustion chamber pass through the gaps between the multiple slag-collecting tubes into the lower furnace. As the flame and pulverized coal pass through the slag-collecting tube bundle, the slag-collecting tubes themselves intercept impurities, and the lower temperature of the outer circumference of the tubes also acts as an adsorption agent, causing impurities to adhere to the tubes and slide off along their extension direction.

[0056] It is understood that the structure of the slag collection device is not limited to including multiple parallel and spaced slag collection tubes. In other embodiments, multiple slag collection tubes are arranged in the form of polygonal sides at the outlet of the molten slag combustion chamber. For example, the slag collection device includes three slag collection tubes arranged in a triangle, and the center line of the triangle coincides with the center line of the outlet of the molten slag combustion chamber.

[0057] In some embodiments, the extension direction of the slag trap bundle has an inclination angle with the vertical direction, and the inclination angle is less than 30°.

[0058] like Figure 1 As shown, the slag-collecting tube bundle at the outlet of the first slag combustion chamber 102 extends downward from top to bottom and tilts to the right, while the slag-collecting tube bundle at the outlet of the second slag combustion chamber 103 extends downward from top to bottom and tilts to the left.

[0059] The tilt angle of less than 30° allows impurities attached to the slag collection tube to slide off on their own, while also ensuring the contact area between the slag collection tube bundle and the flame and coal dust, thus ensuring the effectiveness of impurity collection.

[0060] In some embodiments, the liquid slag discharge boiler of the counter-firing combustion method of the present invention further includes a liquid slag hopper 4 and a water tank 5. The liquid slag hopper 4 has an inlet and an outlet. The liquid slag hopper 4 is connected to the boiler body 1 so that the molten slag combustion chamber is connected to the inlet of the liquid slag hopper 4. One end of the slag collection device 3 is provided on the inner circumferential surface of the liquid slag hopper 4. The outlet of the liquid slag hopper 4 is connected to the water tank 5.

[0061] like Figure 1 As shown, the bottom of the first slag combustion chamber 102 and the second slag combustion chamber 103 are respectively provided with liquid slag hoppers 4. The cross-sectional area of ​​the liquid slag hoppers 4 gradually decreases from top to bottom. The lower end of the slag collection device 3 is located on the inner circumferential surface of the liquid slag hoppers 4. The outlet of the liquid slag hoppers 4 is located at the bottom of the liquid slag hoppers 4. The outlet of the liquid slag hoppers 4 is connected to the water tank 5 through the slag well 13.

[0062] During combustion, the coal flame discharged into the slag combustion chamber by the burner produces molten liquid ash containing alkali metals. The liquid ash containing alkali metals is collected by the liquid ash hopper and discharged into the water tank through the slag well. Impurities captured by the slag trap also slide into the ash hopper and are discharged into the water tank. The water tank contains granulated water. The liquid ash and molten alkali metals are rapidly cooled to form small solid slag particles for subsequent processing.

[0063] In some embodiments, the liquid slag discharge boiler of the counter-firing combustion method of the present invention further includes a slag remover 6, which is connected to a water tank 5 to remove slag particles from the water tank 5.

[0064] like Figure 1 As shown, the slag remover 6 extends in the left-right direction and is simultaneously connected to the water tank 5 corresponding to the first molten slag combustion chamber 102 and the water tank 5 corresponding to the second molten slag combustion chamber 103. Thus, the slag remover 6 removes the slag particles from the water tank 5 corresponding to the first molten slag combustion chamber 102 and the water tank 5 corresponding to the second molten slag combustion chamber 103 for unified processing.

[0065] It is understandable that, in some other embodiments, liquid ash discharge boilers with counter-firing combustion may not be equipped with ash removal machines, and ash particles in the water tank may be removed manually or by other means.

[0066] In some embodiments, the bottom of the boiler body 1 has a dry slag hopper 105, and the internal space of the dry slag hopper 105 is in communication with the furnace 101.

[0067] like Figure 1 As shown, the bottom of the lower furnace 1011 is connected to the internal space of the dry slag hopper 105. The cross-section of the dry slag hopper 105 gradually decreases from top to bottom. The bottom of the dry slag hopper 105 is provided with an outlet, and the outlet of the dry slag hopper 105 is set towards the slag remover 6.

[0068] The unburned pulverized coal discharged into the lower furnace from the slag combustion chamber will produce some slag particles and ash particles that agglomerate into solid particles during combustion. The solid slag particles and ash particles fall and are collected by the dry slag hopper and discharged onto the slag remover, so that the solid slag particles and ash particles are transported and processed together with the slag particles removed from the water tank.

[0069] In some embodiments, the liquid slag discharge boiler of the counter-firing combustion method of the present invention further includes a soot blower 7 and / or a burnout air device 8. The boiler body 1 includes a membrane water-cooled wall, the membrane water-cooled wall surrounds the furnace 101, and the membrane water-cooled wall is provided with a first opening and / or a second opening communicating with the furnace 101.

[0070] The soot blower 7 includes a steam nozzle, a steam pipe and a telescopic mechanism. The telescopic mechanism is located on the outer wall of the membrane water-cooled wall. The telescopic mechanism is equipped with a steam nozzle, and the telescopic mechanism drives the steam nozzle to enter or exit the furnace 101 through the first opening. The steam nozzle is connected to the steam pipe.

[0071] The burnout air device 8 is located on the outer wall surface of the membrane water-cooled wall, and the air outlet of the burnout air device 8 is located in the second opening.

[0072] like Figure 1 As shown, a membrane water-cooled wall surrounds the upper furnace 1012 in the vertical direction, thereby fully exchanging heat with the heat generated by coal combustion. The membrane water-cooled wall is provided with a first opening and a second opening that connects to the furnace 101.

[0073] like Figure 1 As shown, multiple soot blowers 7 are respectively provided on the left and right sides of the boiler body 1, and the multiple soot blowers 7 on any one side are arranged at intervals in the vertical direction. The telescopic mechanism is located on the outer wall surface of the membrane water-cooled wall. The telescopic mechanism can be a telescopic cylinder or a slider mounted on a lead screw. The lead screw is driven by a stepper motor to rotate. The steam nozzle is located at one end of the telescopic mechanism and moves in the left and right direction under the drive of the telescopic mechanism, so that the steam nozzle can pass through the first opening to enter or exit the upper furnace 1012. The steam pipe is connected to the steam nozzle to provide high-pressure steam to the steam nozzle. The soot blowers can promptly blow off the accumulated ash and slag on the heating surface in the furnace, thereby avoiding slagging and contamination of the heating surface.

[0074] like Figure 1 As shown, burnout air devices 8 are respectively installed on the left and right sides of the boiler body 1. The burnout air devices 8 are located on the outer wall surface of the membrane water-cooled wall, and the air outlet of the burnout air device 8 is located in the second opening. The burnout air device is used to provide multi-stage burnout air into the furnace. The burnout air moves along the width and depth of the furnace and mixes thoroughly with the flue gas to achieve secondary combustion, thereby enabling complete combustion of pulverized coal, achieving high combustion efficiency, realizing a low nitrogen oxide combustion mode, and making the flue gas cleaner. In addition, the burnout air device can also make the flue gas temperature distribution in the upper furnace more uniform, which is conducive to the uniform distribution of steam temperature and wall temperature on the heating surface, and can significantly reduce the inlet flue gas temperature of the screen heat exchange surface. Therefore, when burning high-alkali coal, it is less likely to cause slagging, heating surface fouling, and flue gas passage blockage.

[0075] It is understood that, in other embodiments, liquid ash discharge boilers with counter-firing combustion may also lack soot blowers and burnout air devices, or may lack either soot blowers or burnout air devices.

[0076] In some embodiments, the liquid slag discharge boiler of the counter-firing combustion method of the present invention further includes a screen-type heating surface 9, which is connected to the boiler body 1. The boiler body 1 is also provided with a flue gas passage 106, the top of the furnace 101 is connected to the flue gas passage 106, and the top of the furnace 101 and / or the flue gas passage 106 are provided with a screen-type heating surface 9.

[0077] like Figure 1 As shown, the screen-type heating surface 9 includes a front screen superheater 901, a rear screen superheater 902, a high-temperature superheater 903, a high-temperature reheater 904, and a low-temperature reheater 905. The front screen superheater 901, the rear screen superheater 902, the high-temperature superheater 903, and the high-temperature reheater 904 are located at the top of the upper furnace 1012 and are arranged sequentially from left to right. The low-temperature reheater 905 is located in the flue gas passage 106.

[0078] The boiler body 1 includes a front wall and a rear wall. The upper furnace 1012 is provided with a first tube-screen heat exchange surface near the front wall and a second tube-screen heat exchange surface near the rear wall. The front screen superheater 901 is suspended on the top of the upper furnace 1012 and close to the first tube-screen heat exchange surface. The rear screen superheater 902 is suspended on the top of the upper furnace 1012 and close to the second tube-screen heat exchange surface. The high-temperature superheater 903 is used to continue heating the superheated steam that has not reached the rated temperature after being heated by the furnace 101, the front screen superheater 901 and the rear screen superheater 902 in sequence to the rated main steam temperature. The high-temperature reheater 904 is used to heat the turbine exhaust steam that has been heated by the low-temperature reheater 905 to the rated reheat steam temperature.

[0079] In some embodiments, the liquid ash discharge boiler of the offset combustion method of the present invention further includes an economizer 11 and an air preheater 12, which are respectively connected to the boiler body 1, and at least a portion of the economizer 11 and the air preheater 12 are located in the flue gas passage 106.

[0080] like Figure 1 As shown, the economizer 11 is located upstream of the air preheater 12 within the flue gas passage 106. Both the economizer and the air preheater are used to recover the waste heat from the flue gas discharged from the flue gas passage 106.

[0081] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0082] Furthermore, the terms "first" and "second" are used only to distinguish components or directions and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0083] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0084] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0085] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0086] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A liquid ash discharge boiler with a counter-firing combustion method, characterized in that, include: The boiler body (1) is provided with a furnace (101) and a slag combustion chamber. The slag combustion chamber has an inlet and an outlet. The outlet of the slag combustion chamber is connected to the furnace (101). The slag combustion chamber includes a first slag combustion chamber (102) and a second slag combustion chamber (103). The first slag combustion chamber (102) is located on one side of the furnace (101), and the second slag combustion chamber (103) is located on the other side of the furnace (101). The outlets of the first slag combustion chamber (102) and the second slag combustion chamber (103) are arranged opposite to each other. Burner (2), the burner (2) is connected to the boiler body (1) so that the outlet of the burner (2) is connected to the inlet of the slag combustion chamber. The burner (2) is a cyclone burner. The coal is ignited and burned in the cyclone burner and the slag combustion chamber and most of the ash and slag components are removed under the capture effect of the slag combustion chamber. After the coal is ignited by the burner, it first undergoes ignition and combustion in the molten slag combustion chamber under a liquid slag film environment. The alkali metals are solidified and captured through physical and chemical reactions, so that most of the ash components are intercepted outside the furnace in the form of liquid slag. The coal flame with low ash content discharged from the burner needs to pass through the molten slag combustion chamber along the extension direction of the molten slag combustion chamber before it can enter the furnace for counter-firing combustion and burn out in the furnace. The outlet temperature of the molten slag combustion chamber is 1500℃~1600℃. The furnace (101) includes a lower furnace (1011) and an upper furnace (1012). The lower furnace (1011) is connected to the upper furnace (1012) and is located below the upper furnace (1012). The outlet of the slag combustion chamber is connected to the lower furnace (1011). The upper furnace (1012) is higher than the lower furnace (1011), and the top of the upper furnace (1012) is provided with a multi-stage screen-type heating surface. The higher space of the upper furnace (1012) allows the heat generated by the combustion of pulverized coal to be reduced to 800℃-900℃ when it moves to the bottom of the screen-type heating surface.

2. The liquid ash discharge boiler with counter-firing combustion method according to claim 1, characterized in that, The furnace chamber (101) extends in the vertical direction. The furnace chamber (101) has a first slag combustion chamber (102) on one side of the first direction and a second slag combustion chamber (103) on the other side of the first direction. The first direction is orthogonal to the vertical direction. The slag combustion chamber extends along the first direction. The opening direction of the outlet and the opening direction of the inlet of the slag combustion chamber are both parallel to the first direction, and the opening direction of the outlet and the opening direction of the inlet of the slag combustion chamber are opposite.

3. The liquid ash discharge boiler with counter-firing combustion method according to claim 2, characterized in that, The boiler body (1) has a recess (104) that surrounds the boiler body (1) around its central axis and is located at the connection point between the lower furnace (1011) and the upper furnace (1012).

4. The liquid ash discharge boiler with counter-firing combustion method according to claim 1, characterized in that, It also includes a slag-collecting device (3), which is connected to the boiler body (1) and located at the outlet of the slag combustion chamber.

5. The liquid ash discharge boiler with counter-firing combustion method according to claim 4, characterized in that, The slag collection device (3) includes a slag collection tube bundle, which includes a plurality of parallel and spaced-apart slag collection tubes, and the slag collection tubes contain a cooling medium.

6. The liquid ash discharge boiler with counter-firing combustion method according to claim 5, characterized in that, The extension direction of the slag-collecting tube bundle has an inclination angle between the vertical direction and the vertical direction, and the inclination angle is less than 30°.

7. The liquid ash discharge boiler with counter-firing combustion method according to claim 4, characterized in that, It also includes a liquid slag hopper (4) and a water tank (5). The liquid slag hopper (4) has an inlet and an outlet. The liquid slag hopper (4) is connected to the boiler body (1) so that the molten slag combustion chamber is connected to the inlet of the liquid slag hopper (4). One end of the slag trap (3) is located on the inner circumferential surface of the liquid slag hopper (4). The outlet of the liquid slag hopper (4) is connected to the water tank (5).

8. The liquid ash discharge boiler with counter-firing combustion method according to claim 7, characterized in that, It also includes a slag remover (6), which is connected to the water tank (5) to remove slag particles from the water tank (5).

9. The liquid ash discharge boiler with counter-firing combustion according to claim 1, characterized in that, The bottom of the boiler body (1) has a dry slag hopper (105), and the internal space of the dry slag hopper (105) is connected to the furnace (101).

10. A liquid ash discharge boiler with counter-firing combustion according to any one of claims 1-9, characterized in that, It also includes a soot blower (7) and / or a burnout air device (8), the boiler body (1) includes a membrane water-cooled wall surrounding the furnace (101), and the membrane water-cooled wall is provided with a first opening and / or a second opening communicating with the furnace (101); The soot blower (7) includes a steam nozzle, a steam pipe and a telescopic mechanism. The telescopic mechanism is located on the outer wall of the membrane water-cooled wall. The telescopic mechanism is equipped with the steam nozzle, and the telescopic mechanism drives the steam nozzle to enter or exit the furnace (101) through the first opening. The steam nozzle is connected to the steam pipe. The burnout air device (8) is located on the outer wall surface of the membrane water-cooled wall, and the air outlet of the burnout air device (8) is located in the second opening.

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