A device and method for collecting gasified ash slurry liquid in a four-corner tangential manner for a boiler

Abstract

A four-corner circular disposal device for gasification ash slurry for boilers belongs to the technical field of boilers. The present invention includes a furnace, a slurry / coal powder dual-purpose burner, a secondary air nozzle, a bottom air nozzle, a compact burnout air layer and a separated burnout air layer. The slurry / coal powder dual-purpose burners are arranged in layers in the furnace, and the slurry / coal powder dual-purpose burners of each layer are arranged at the four corners of the furnace. The secondary air nozzle is fixedly installed on the furnace, and the bottom of the furnace is provided with a bottom air nozzle, and the top of the furnace is provided with a separated burnout air layer and a compact burnout air layer from top to bottom. The purpose of the research and development of the present invention is to solve the problems of coal gasification ash treatment process requiring dehydration, complicated process, incomplete combustion, and difficulty in controlling the combustion speed. It does not require a drying process, nor does it require preheating in advance. It can be burned by spraying into the slurry / coal powder dual-purpose burner, which reduces the difficulty of operation and enables the gasification ash to be disposed of on a large scale.

Description

Technical Field

[0001] The invention relates to a four-corner tangential circle disposal device for gasified ash slurry liquid used in boilers, belonging to the technical field of boilers. Background Art

[0002] The emission of coal gasification slag is very large, and the technology and means for large-scale disposal of the produced gasification ash are not yet mature, and the universality of resource utilization cannot be guaranteed. Therefore, storage and landfill are still the main treatment methods for gasification slag, which not only occupies a large amount of land resources, but also causes serious environmental pollution.

[0003] Coal-water slurry (CWS) is a heterogeneous liquid-solid suspension composed of 65% to 70% pulverized coal, 30% to 35% water, and a small amount of additives. Its combustion system, similar to fuel oil, utilizes spray combustion, resulting in efficient combustion and stable operation. The flame and temperature are also easily controlled and regulated. Given my country's national conditions and the characteristics of CWS, CWS is undoubtedly a relatively suitable quasi-clean energy source today, offering advantages in preparation and transportation.

[0004] Coal gasification slag is typically divided into coarse slag obtained at the furnace bottom and fly ash. Coarse slag has a low carbon content and can be directly recycled. Fly ash generally has a high residual carbon content and cannot be disposed of on a large scale. This is especially true because most gasification slag is highly water-rich. Although dry ash is also present, the water content is even greater. Therefore, most technologies require dehydration equipment.

[0005] The existing invention patent, "Gasification Ash Incineration System and Combustion Method," has patent number CN202311075189.6, authorization publication number CN117053207A, and authorization publication date November 14, 2023 (hereinafter referred to as "Document 1"). This invention patent designs a coal gasification ash incineration system that treats gasified ash by incinerating it; this method can solve the problems of difficult ignition and complete combustion of coal gasification ash. However, this patent uses too much equipment and an overly complex process, making it prone to equipment problems.

[0006] The existing invention patent "A two-stage drying, preheating and incineration system for high-moisture gasified ash" has a patent number of CN202311110942.0, an authorization number of CN116928680A, and an authorization announcement date of October 24, 2023, hereinafter referred to as "Document 2". This invention patent designs a two-stage drying, preheating and incineration system for high-moisture gasified ash, which preheats the gasified ash first, and then the preheated gasified ash enters the incineration boiler for combustion, thereby efficiently recycling the combustible heat in the gasified ash, and dehydrates it during the preheating process to reduce the process. However, there are problems such as the use of many equipments, complex implementation methods, and low efficiency in the combustion process. The preheating process is increased, which in turn increases energy consumption and requires large investment. In addition, the system needs to be dehydrated before being burned for utilization.

[0007] The existing invention patent "A device and method for direct combustion of high-water-content coal gasification ash" has a patent number of CN202111496300.X, an authorization number of CN114046505A, and an authorization announcement date of February 15, 2022, hereinafter referred to as "Document Three". This invention patent provides a device for direct combustion of high-water-content coal gasification ash. The device has the characteristics of high water content of the burned gasified ash, low heat consumption, low production cost, and environmental friendliness. However, it also has the problems of using many equipment, complex implementation methods, low efficiency in the combustion process, large investment, and the need to dehydrate first and then burn for utilization.

[0008] Therefore, it is urgent to propose a new type of gasification ash slurry liquid four-corner tangential circle disposal device for boilers to solve the above technical problems. Summary of the Invention

[0009] The purpose of this invention is to address the issues of coal gasification ash treatment, such as the need for dehydration, complex processes, incomplete combustion, and difficulty controlling the combustion rate. By utilizing gasification ash to create a gasification ash slurry, the slurry is then passed through a tangentially-shaped boiler for combustion to treat large quantities of gasification ash waste. A brief overview of the invention is provided below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive overview of the invention. It is not intended to identify key or important aspects of the invention, nor is it intended to limit the scope of the invention.

[0010] The technical solution of the present invention:

[0011] Option 1: A four-corner tangential circular disposal device for gasified ash slurry for boilers, comprising a furnace, a slurry / pulverized coal dual-purpose burner, a secondary air nozzle, a bottom air nozzle, a compact burnout air layer and a separated burnout air layer. The slurry / pulverized coal dual-purpose burners are arranged in layers in the furnace, and the slurry / pulverized coal dual-purpose burners of each layer are arranged at the four corners of the furnace. The secondary air nozzle is fixedly mounted on the furnace, a bottom air nozzle is provided at the bottom of the furnace, and a separated burnout air layer and a compact burnout air layer are provided on the top of the furnace from top to bottom.

[0012] Preferably, the slurry / coal powder dual-purpose burner is provided with a coal powder nozzle and a slurry nozzle, and the coal powder nozzle and the slurry nozzle are respectively connected to the feeder through valves.

[0013] Preferably, six layers of slurry / pulverized coal dual-purpose burners are longitudinally arranged in the furnace, and a secondary air nozzle is provided between every two adjacent layers of slurry / pulverized coal dual-purpose burners.

[0014] Preferably, two layers of bottom air nozzles are provided at the bottom of the furnace.

[0015] Preferably, the compact burnout air layer is arranged in two layers, and the separated burnout air layer is arranged in six layers.

[0016] Preferably, the slurry / coal powder dual-purpose burner sprays coal powder or gasified ash slurry into the furnace at the four corners thereof, and the spraying directions are four different tangential directions of the same circle.

[0017] Solution 2: A method for collecting gasified ash slurry liquid from a boiler by using a four-corner tangential circular method, which is implemented based on the device for collecting gasified ash slurry liquid from a boiler by using a four-corner tangential circular method described in Solution 1, and includes the following steps:

[0018] Step 1: Calculate the heat required to completely evaporate the water in the gasified ash slurry;

[0019] Step 2: Prepare slurry and store the prepared gasification ash slurry and coal powder in a feeder respectively;

[0020] Step 3: Start the feeder, slurry / pulverized coal dual-purpose burner, secondary air nozzle and bottom air nozzle. The secondary air nozzle introduces middle secondary air into the furnace, and the bottom air nozzle introduces bottom secondary air into the furnace. The prepared gasified ash slurry and pulverized coal are passed into the slurry / pulverized coal dual-purpose burner through the valve, and the slurry / pulverized coal dual-purpose burner is used to spray and burn into the furnace.

[0021] Preferably, in the step 2 of preparing the slurry, when the carbon content in the gasified ash is greater than 30%, the gasified ash slurry is directly prepared; when the carbon content in the gasified ash is less than 30%, coal powder is mixed to prepare the slurry.

[0022] The present invention has the following beneficial effects:

[0023] 1. The present invention does not require a drying process or preheating in advance. It can be burned by spraying it into a slurry / coal powder dual-purpose burner, which reduces the difficulty of operation and enables large-scale disposal of gasified ash;

[0024] 2. The present invention requires low investment and simple structure, does not require a separate dehydration device for dehydration, has little slagging and high efficiency;

[0025] 3. The present invention has a flexible design and can flexibly adjust the number of slurry / coal powder dual-purpose burners that feed the slurry, thereby changing the rate of consuming gasified ash. This is more efficient, safer, more reliable, and economical.

[0026] 4. The fuel introduced into the furnace of the present invention, i.e., the gasified ash slurry or pulverized coal, only needs to have combustion characteristics and the calorific value does not need to be too high. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the coordination of the slurry / coal powder dual-purpose burner and the secondary air nozzle in the furnace of the present invention;

[0028] Figure 2 It is a schematic diagram of the arrangement inside the furnace of the present invention;

[0029] Figure 3 Schematic diagrams of the use of the slurry / pulverized coal dual-purpose burner of the present invention, wherein (a) is a schematic diagram of the use of introducing gasified slurry liquid into four corners, (b) is a schematic diagram of the use of introducing gasified slurry liquid into one corner, (c) is a schematic diagram of the use of introducing gasified slurry liquid into two corners, and (d) is a schematic diagram of the use of introducing gasified slurry liquid into a triangular shape;

[0030] Figure 4 Schematic diagram of the coordination of the feeder and the slurry / coal powder dual-purpose burner of the present invention;

[0031] In the figure, 1-furnace, 2-slurry / pulverized coal dual-purpose burner, 3-secondary air nozzle, 4-bottom air nozzle, 5-compact burnout air layer, 6-separated burnout air layer, 7-valve, 8-feeder. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention is described below using specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0033] The connections mentioned in the present invention are divided into fixed connections and detachable connections. The fixed connection refers to a non-detachable connection, including but not limited to conventional fixed connection methods such as hem connection, rivet connection, adhesive connection, and welding connection. The detachable connection refers to but not limited to conventional detachable connection methods such as threaded connection, snap connection, pin connection, and hinge connection. When the specific connection method is not clearly specified, it is assumed that at least one connection method can always be found among the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example, a welded connection is selected for a fixed connection, and a hinge connection is selected for a detachable connection.

[0034] Specific implementation method 1: Combination Figures 1-4 To illustrate this embodiment, a four-corner circular disposal device for gasified ash slurry for a boiler in this embodiment includes a furnace 1, a slurry / coal powder dual-purpose burner 2, a secondary air nozzle 3, a bottom air nozzle 4, a compact burnout air layer 5 and a separated burnout air layer 6. The slurry / coal powder dual-purpose burners 2 are arranged in layers in the furnace 1, and the slurry / coal powder dual-purpose burners 2 of each layer are arranged at the four corners of the furnace 1. The secondary air nozzle 3 is fixedly installed on the furnace 1. A bottom air nozzle 4 is provided at the bottom of the furnace 1, and a separated burnout air layer 6 and a compact burnout air layer 5 are provided on the top of the furnace from top to bottom.

[0035] The slurry / coal powder dual-purpose burner 2 is provided with a coal powder nozzle and a slurry nozzle, and the coal powder nozzle and the slurry nozzle are respectively connected to the feeder 8 through a valve 7, and the feeder 8 provides coal powder or gasified ash slurry liquid. Then, the valve 7 can be used to control the pipeline switching, so that they can be used separately as a coal powder nozzle and a slurry nozzle; the coal powder nozzle sprays coal powder, and the gasified ash slurry nozzle sprays gasified ash slurry liquid.

[0036] The feeder 8 includes a pulverized coal bin and a slurry bin. The pulverized coal bin stores pulverized coal, which is ejected from the pulverized coal nozzle of the slurry / pulverized coal dual-purpose burner 2 through a valve 7 and a pipeline. The slurry bin stores gasified ash slurry, which is ejected from the slurry nozzle of the slurry / pulverized coal dual-purpose burner 2 through a valve 7 and a pipeline.

[0037] Six layers of slurry / coal powder dual-purpose burners 2 are longitudinally arranged in the furnace 1, and a secondary air nozzle 3 is provided between each two adjacent layers of slurry / coal powder dual-purpose burners 2. The secondary air nozzle 3 introduces secondary air to dry and dehydrate the gasified ash slurry and water-coal slurry in the furnace 1, so as to ensure sufficient combustion.

[0038] Two layers of bottom air nozzles 4 are provided at the bottom of the furnace 1 .

[0039] The compact burnt-out air layer 5 is arranged in two layers, and the separated burnt-out air layer 6 is arranged in six layers.

[0040] The slurry / coal powder dual-purpose burner 2 sprays coal powder or gasified ash slurry into the furnace 1 at the four corners thereof, and the spraying directions are four different tangential directions of the same circle.

[0041] Specific implementation method 2: Combination Figures 1-4 This embodiment is described based on the specific embodiment 1. In this embodiment, a gasification ash slurry liquid four-corner tangential circle disposal device for boilers is used. Figure 2 As shown, the 6-layer slurry / coal powder dual-purpose burner 2 is A layer, B layer, C layer, D layer, E layer, and F layer from bottom to top;

[0042] Secondary air nozzles 2 are arranged between two adjacent layers of slurry / pulverized coal dual-purpose burners 2, namely AB layer secondary air, BC layer secondary air, CD1 layer secondary air, CD2 layer secondary air, DE layer secondary air, EF layer secondary air, among which CD1 layer secondary air and CD2 layer secondary air are arranged adjacently between C layer and D layer;

[0043] Two layers of bottom air nozzles 4 are provided at the lower part of the furnace 1 to form two layers of bottom secondary air, namely, AA1 layer secondary air and AA2 layer secondary air;

[0044] A compact burnt-out air layer 5 is provided at the upper end of the furnace 1, namely, the COFA1 layer secondary air and the COFA2 layer secondary air;

[0045] Six groups of separated burnt-out air layers 6 are arranged above the furnace 1, namely SOFA1 layer secondary air, SOFA2 layer secondary air, SOFA3 layer secondary air, SOFA4 layer secondary air, SOFA5 layer secondary air, and SOFA6 layer secondary air.

[0046] The pulverized coal nozzle, slurry nozzle, secondary air nozzle 3, bottom air nozzle 4 and secondary air nozzle 3 can all swing up and down;

[0047] In a more preferred technical solution, the F layer is used as a gasification slurry layer, and the four slurry / coal powder dual-purpose burners 2 in this layer can flexibly adjust the selection of spraying gasification slurry or coal powder;

[0048] like Figure 3 As shown, the number of slurry nozzles for introducing the gasified ash slurry liquid can be 1 to 4, that is, the gasified ash slurry liquid can be introduced into the slurry / coal powder dual-purpose burner 2 at one corner, or the gasified ash slurry liquid can be introduced into the gasified ash slurry at two corners, or the gasified ash slurry liquid can be introduced into the gasified ash slurry at three corners, or the gasified ash slurry liquid can be introduced into the gasified ash slurry at four corners; the valve 7 can also be used to control the slurry / coal powder dual-purpose burners 2 at the four corners to introduce coal powder.

[0049] A more preferred technical solution is to adjust the number of gasified ash slurry layers according to the rate of gasified ash consumption, for example, the F layer can be a gasified ash slurry layer, or the E and F layers can be gasified ash slurry layers, or the D, E, and F layers can be gasified ash slurry layers;

[0050] It should be noted that, since the pulverized coal layer is fully burned, the gasification slurry layer into which the gasification slurry liquid is sprayed needs to be designed on the pulverized coal layer into which the pulverized coal is sprayed. The heat generated by the combustion of the pulverized coal layer will drive the combustion of the gasification ash layer, and the gasification slurry will produce less slagging, which will improve the problems of difficult ignition and burning of gasification ash slag in existing technologies. The center of the combustion flame can be prevented from shifting by controlling the fineness of the pulverized coal and the concentration of the gasification slurry liquid and adjusting the secondary air volume.

[0051] Specific implementation method three: Combination Figures 1-4 This embodiment describes a method for collecting gasified ash slurry in a boiler by cutting into four corners. This method is based on the device for collecting gasified ash slurry in a boiler by cutting into four corners as described in the second embodiment. The method is characterized by comprising the following steps:

[0052] Step 1: Calculate the heat required to completely evaporate the water in the gasified ash slurry:

[0053] Coal-water slurry is a heterogeneous liquid-solid suspension liquid composed of 65% to 70% coal powder, 30% to 35% water and a small amount of additives, with water accounting for 30% to 35%.

[0054] The heat required for complete evaporation of water in the gasified ash slurry is calculated as follows:

[0055] Q=cmΔT

[0056] Where m_ is the mass of water (in grams), c_ is the specific heat capacity of water, and ΔT is the temperature change as the water warms (or evaporates), usually the boiling point of water minus the initial temperature (usually room temperature).

[0057] Therefore, if the carbon content of the gasified ash is greater than 30%, it can be directly burned in the boiler for full combustion; if the carbon content of the gasified ash is less than 30%, it needs to be burned with pulverized coal; if necessary, recycled flue gas can be introduced so that the heat generated by the combustion of the gasified ash and the heat of the flue gas can remove the moisture from the gasified ash slurry and completely burn it;

[0058] Step 2, preparing slurry:

[0059] Step 2.1, pretreatment of gasification ash: separating gasification fine slag from gasification coarse slag; taking the gasification fine slag and adding water to mix to obtain black water, which is set aside; adding water to the gasification coarse slag and stirring to obtain gasification coarse slag material, which is set aside;

[0060] Step 2.2, slurry preparation: grind and mix the raw materials, black water or gasification coarse slag, and additives to obtain water-coal slurry.

[0061] The prepared gasification slurry and coal powder are stored in the feeder 8 respectively;

[0062] Step 3, start the feeder 8, the slurry / pulverized coal dual-purpose burner 2, the secondary air nozzle 3 and the bottom air nozzle 4, the secondary air nozzle 3 introduces the middle secondary air into the furnace 1, and the bottom air nozzle 4 introduces the bottom secondary air into the furnace 1, and the prepared gasified ash slurry and pulverized coal are introduced into the slurry / pulverized coal dual-purpose burner 2 through the valve 7, and the slurry / pulverized coal dual-purpose burner 2 is sprayed into the interior of the furnace 1 and burned.

[0063] Since the calorific value of gasification ash with a carbon content greater than 30% is generally 3000 kcal / kg, it can be burned in a boiler, while the gasification ash with a carbon content less than 30% needs to be mixed with coal powder to be fully burned in the boiler. Therefore, in the preparation of the slurry in step 2, when the carbon content in the gasification ash is greater than 30%, the gasification ash slurry is directly prepared, and when the carbon content in the gasification ash is less than 30%, the slurry is prepared by mixing with coal powder.

[0064] This embodiment takes a 660MW square cut circle boiler as an example. It can burn about 250 tons of coal powder in 1 hour. According to the method of this embodiment, it can burn about 6 tons of gasification ash in 1 hour. If it works for 10 hours a day, it can burn about 60 tons of gasification ash. If the method of this embodiment is adopted, 2,000 660MW square cut circle boilers can consume 33 million tons of gasification ash in about 225 days. This embodiment can also adjust the number of gasification ash slurry layers to adjust the number of tons of gasification ash burned per day.

[0065] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutations and combinations. Therefore, the present invention will no longer describe the technical solutions after permutations and combinations one by one, but it should be understood that the technical solutions after permutations and combinations have been disclosed by the present invention.

[0066] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A four-corner tangential circle disposal device for gasified ash slurry liquid used in boilers, characterized by: The invention comprises a furnace (1), a slurry / coal powder dual-purpose burner (2), a secondary air nozzle (3), a bottom air nozzle (4), a compact burnout air layer (5), and a separated burnout air layer (6); the slurry / coal powder dual-purpose burner (2) is arranged in layers in the furnace (1), and the slurry / coal powder dual-purpose burner (2) of each layer is arranged at the four corners of the furnace (1); the secondary air nozzle (3) is fixedly mounted on the furnace (1); the bottom of the furnace (1) is provided with a bottom air nozzle (4); and the top of the furnace is provided with a separated burnout air layer (6) and a compact burnout air layer (5) in order from top to bottom; Also included is a method for collecting gasified ash slurry liquid in a boiler by using a four-corner tangential circular method, which is implemented by relying on the device for collecting gasified ash slurry liquid in a boiler by using a four-corner tangential circular method, and includes the following steps: Step 1: Calculate the heat required to completely evaporate the water in the gasified ash slurry; Coal-water slurry is a heterogeneous liquid-solid suspension consisting of 65% to 70% coal powder, 30% to 35% water and additives, with water accounting for 30% to 35%; The heat required for complete evaporation of water in the gasified ash slurry is calculated as follows: Q=cmΔT Where m is the mass of water, c is the specific heat capacity of water, and ΔT is the temperature change of water as it warms or evaporates; Therefore, if the carbon content of the gasified ash is greater than 30%, it is directly burned in the boiler for complete combustion; if the carbon content of the gasified ash is less than 30%, it is burned with pulverized coal; recycled flue gas is introduced so that the heat generated by the combustion of the gasified ash and the heat of the flue gas can remove the moisture from the gasified ash slurry and completely burn it; Step 2, preparing slurry, and storing the prepared gasification ash slurry and coal powder into a feeder (8) respectively; Step 2.1, pretreatment of gasification ash: separating gasification fine slag from gasification coarse slag; taking the gasification fine slag and adding water to mix to obtain black water, which is set aside; adding water to the gasification coarse slag and stirring to obtain gasification coarse slag material, which is set aside; Step 2.2, slurry preparation: grinding and mixing the raw materials, black water or gasification coarse slag, and additives to obtain water-coal slurry; Step 3, start the feeder (8), the slurry / coal powder dual-purpose burner (2), the secondary air nozzle (3) and the bottom air nozzle (4), the secondary air nozzle (3) introduces the middle secondary air into the furnace (1), the bottom air nozzle (4) introduces the bottom secondary air into the furnace (1), the prepared gasified ash slurry and coal powder are introduced into the slurry / coal powder dual-purpose burner (2) through the valve (7), and the slurry / coal powder dual-purpose burner (2) is sprayed into the furnace (1) and burned; the slurry / coal powder dual-purpose burner (2) is provided with a coal powder nozzle and a slurry nozzle, and the coal powder nozzle and the slurry nozzle are respectively connected to the feeder (8) through the valve (7); the furnace (1) is longitudinally provided with 6 layers of A slurry / coal powder dual-purpose burner (2) is provided, and a secondary air nozzle (3) is provided between each two adjacent layers of the slurry / coal powder dual-purpose burner (2); two layers of bottom air nozzles (4) are provided at the bottom of the furnace (1); the compact burnout air layer (5) is arranged in two layers, and the separated burnout air layer (6) is arranged in six layers; the slurry / coal powder dual-purpose burner (2) sprays coal powder or gasified ash slurry at the four corners of the furnace (1), and the spraying direction is four different tangential directions of the same circle; in the preparation of the slurry in the step 2, when the carbon content in the gasified ash is greater than 30%, the gasified ash slurry is directly prepared, and when the carbon content in the gasified ash is less than 30%, the slurry is prepared by mixing with coal powder.

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