Coal gasification slag and biomass coupled fuel as well as preparation method and preparation and utilization system thereof

Abstract

The invention discloses coal gasification slag and biomass coupled fuel as well as a preparation method and a preparation and utilization system thereof, and belongs to the technical field of fuel and boiler systems. The coal gasification slag and biomass coupled fuel comprises 50-70 parts of gasification fine slag, 25-50 parts of biomass and 5-10 parts of a binder, the gasification slag is coal water slurry furnace gasification slag, the biomass is sea-buckthorn, the binder comprises 1-2 parts of kaolin, 3-8 parts of coal tar and 1-2 parts of starch, and the two raw materials and the binder are evenly mixed and then subjected to hot press molding at the temperature of 100-250 DEG C. The coal gasification slag needs to be dried before forming, the biomass needs to be crushed before forming, the forming mode is hot press forming, the formed fuel can be combusted in a fluidized bed boiler, and heat generated by combustion can be used for drying and hot press forming of the coal gasification slag. After molding, the cycle index in a fluidized bed boiler is increased, the retention time is prolonged, the strength of the fuel is excellent, and the coking condition can be relieved.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel and boiler systems, and relates to a coal gasification slag and biomass coupling fuel, a preparation method thereof, and a preparation and utilization system thereof. Background Art

[0002] Gasification slag is one of the by-products produced during coal gasification, mainly from entrained-bed gasification technology. The residual carbon content in gasification fine slag is high, and direct landfill or storage not only wastes energy, but also requires prevention of spontaneous combustion. If this part of residual carbon is utilized, the energy utilization efficiency can be improved.

[0003] Biomass refers to various organisms produced through photosynthesis using the atmosphere, water, land, etc., that is, all living organic matter that can grow is generally called biomass.

[0004] The gasification slag has a high residual carbon content but a fine particle size, especially the problem of small particle size, which limits its combustion in the fluidized bed boiler. Due to the small particle size of the gasification slag, it is not fully burned and is discharged from the furnace with the flue gas. After passing through the cyclone separator, it is difficult to return to the fuel cycle, the number of cycles is small, and the residual carbon burnout rate is low. In addition, after the unburned gasification slag is discharged with the flue gas, the amount of fly ash in the boiler increases significantly, the load of the dust removal equipment at the rear end of the boiler increases, and the wall and heating surface need to be optimized for wear protection, which greatly increases the cost. To avoid these problems, it is necessary to modify the equipment or optimize the pretreatment of the gasification slag fuel.

[0005] Biomass fuel is low-cost and widely available. Its application in fluidized bed boilers can reduce operating costs and improve the economic efficiency of equipment. However, biomass fuel has a high content of alkali metals, which will inevitably have adverse effects on the unit during the combustion process, including corrosion and coking. Therefore, the application of biomass in fluidized bed boilers also needs to be improved. Summary of the invention

[0006] The purpose of the present invention is to provide a coal gasification slag and biomass coupled fuel and its preparation method and preparation and utilization system to solve the technical problems of low fuel burnout rate in the prior art fluidized bed boiler and easy to cause adverse effects such as corrosion and coking on the unit.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a coal gasification slag and biomass coupling fuel, the components of which include 25 to 50 parts of biomass, 50 to 70 parts of coal gasification slag, and 5 to 10 parts of a binder by weight.

[0008] Furthermore, the biomass is a mixture of one or more of sea buckthorn, salix psammophila, wormwood and spatholobi; and the coal gasification slag is coal-water slurry furnace gasification slag.

[0009] Furthermore, the binder comprises, by weight, 1 to 2 parts of kaolin, 3 to 8 parts of coal tar, and 1 to 2 parts of starch.

[0010] In a second aspect, the present invention provides a method for preparing the above-mentioned coal gasification slag and biomass coupled fuel, comprising the following steps: The coal gasification slag and biomass are pre-treated separately, mixed after reaching the preset moisture content and particle size, and then a binder is added and stirred; The stirred mixture is pressed by a hot press to obtain a coupling fuel of a preset size.

[0011] Furthermore, the water content of the pretreated coal gasification slag is 15% to 30%, and the particle size is less than 180 μm.

[0012] Furthermore, the moisture content of the biomass after pretreatment is 10% to 20%, and the particle size is >100 mesh.

[0013] Furthermore, the temperature during the hot press molding process is 100°C to 250°C, and the molding pressure is 5 MPa to 25 MPa.

[0014] Furthermore, the coupling fuel of the preset size is cylindrical, with a diameter of 10 mm to 15 mm and a height of 5 mm to 10 mm.

[0015] In a third aspect, the present invention provides a system for preparing and utilizing a coal gasification slag and biomass coupled fuel, based on the above-mentioned method for preparing a coal gasification slag and biomass coupled fuel, comprising: A pretreatment unit, the pretreatment unit comprising a first heat exchanger, a pulverizer and a second heat exchanger; the coal gasification slag is dried by the first heat exchanger and then transported to the mixing and molding unit; the biomass is sequentially transported to the mixing and molding unit after passing through the pulverizer and the second heat exchanger; A mixed molding unit, the mixed molding unit comprising a feeder, a mixer and a press connected in sequence; the inlet of the mixer is also connected to the outlets of the first heat exchanger and the second heat exchanger; the outlet of the press is connected to the combustion unit; A combustion unit, the combustion unit comprises a storage bin, a fan, a furnace, a cyclone separator and a material return mechanism; the inlet of the storage bin is connected to the outlet of the forming press, and the outlet of the storage bin is connected to the front end of the furnace; the fan is installed at the front end of the furnace, and the tail end of the furnace is connected to the cyclone separator; the bottom of the cyclone separator is connected to the front end of the furnace through the material return mechanism.

[0016] Furthermore, the mixed molding unit also includes a heat recovery flue gas duct; the inlet of the heat recovery flue gas duct is connected to the top of the cyclone separator, the first outlet of the heat recovery flue gas duct is connected to the molding machine, the second outlet of the heat recovery flue gas duct is connected to the high-temperature side inlet of the first heat exchanger, and the high-temperature side outlet of the first heat exchanger is connected to the high-temperature side inlet of the second heat exchanger; a dust collector is also installed at the inlet of the heat recovery flue gas duct.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a coupled fuel of coal gasification slag and biomass and a preparation method thereof. The coupled fuel is made of large particles by coupling coal gasification slag and biomass. The coupled fuel has excellent strength and suitable size and can be burned in a circulating fluidized bed boiler. The interaction between coal gasification slag and biomass in the coupled fuel is obvious. The biomass acts as a binder, so that the coal gasification slag can be pressed into particles, which greatly improves the situation that the original coal gasification slag cannot be fully burned in the circulating fluidized bed boiler. In turn, the coal gasification slag can fix the alkali metal elements in the biomass, and reduce the corrosion and coking effects on the boiler caused by the biomass blending.

[0018] The invention discloses a preparation and utilization system of coal gasification slag and biomass coupled fuel. During the combustion process, particles are burned from the outside to the inside, the intensity of the burned part is reduced, and it can be separated from the fuel particles and discharged from the furnace with the flue gas through a cyclone separator; the intensity of the burning or unburned part still exists, and it is not discharged with the flue gas when passing through the cyclone separator, but continues to return to the furnace to burn until it is completely burned, thereby increasing the number of cycles and improving the economic efficiency of the unit operation.

[0019] Furthermore, the high-temperature flue gas generated by combustion in the system of the present invention provides a heat source for the production of coupled fuels through a heat recovery flue gas pipeline. The fuel production stage does not require the use of an external heat source. A portion of the high-temperature flue gas generated after the combustion of gasified slag and biomass coupled fuel enters the heat recovery flue gas pipeline and is then divided into two streams, which provide heat for the gasified slag and biomass drying process and the fuel molding process, greatly controlling the cost required for fuel production. The coupled fuel and utilization system of the present invention is not only of great significance for the disposal of coal gasification slag, but also reduces operating costs and enhances the efficiency of solid waste resource utilization in terms of production preparation, combustion efficiency, and maintenance of the boiler system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a structural schematic diagram of the system of the present invention; Figure 2 The compressive strength of the coupled fuel at different molding temperatures in the embodiments of the present invention; Figure 3 The compressive strength of the coupled fuel under different molding pressures in the embodiment of the present invention; Figure 4 The weight loss data of coupled fuel combustion at different molding temperatures in the embodiments of the present invention; Figure 5 The figures are the weight loss data of coupled fuel combustion under different molding pressures in the embodiments of the present invention.

[0022] Among them: 1. Gasification slag; 2. Biomass; 31. First heat exchanger; 32. Second heat exchanger 4. Crusher; 5. Feeder; 6. Mixer; 7. Press; 8. Storage bin; 9. Fan; 10. Coupled fuel particles; 11. Furnace; 12. Cyclone separator; 13. Unburned fuel; 14. Burned fuel; 15. Return mechanism; 16. Dust collector; 17. Heat recovery flue gas duct. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0027] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0030] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0031] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings: The embodiment of the present invention discloses a coal gasification slag and biomass coupling fuel, which comprises 25 to 50 parts of biomass, 50 to 70 parts of coal gasification slag, and 5 to 10 parts of a binder by weight.

[0033] It should be noted that the biomass is a mixture of one or more of sea buckthorn, salix psammophila, wormwood and spatholobi; the coal gasification slag is coal-water slurry furnace gasification slag. The binder is calculated by weight, and the specific components include 1-2 parts of kaolin, 3-8 parts of coal tar, and 1-2 parts of starch.

[0034] The embodiment of the present invention discloses a method for preparing the above-mentioned coal gasification slag and biomass coupled fuel, comprising the following steps: S1, pre-treating coal gasification slag and biomass respectively, mixing them after reaching a preset moisture content and particle size, and then adding a binder and stirring; In this step, the water content of the pretreated coal gasification slag is 15% to 30%, and the particle size is <180 μm. The water content of the pretreated biomass is 10% to 20%, and the particle size is >100 mesh.

[0035] S2, pressing the stirred mixture into a mold using a hot press to obtain a coupling fuel of a preset size.

[0036] In this step, the temperature of the hot press during the molding process is 100°C to 250°C, and the molding pressure is 5 MPa to 25 MPa. The coupling fuel of the preset size is cylindrical, with a diameter of 10 mm to 15 mm and a height of 5 mm to 10 mm.

[0037] Gasified slag cannot be burned in a fluidized bed boiler due to its small particle size. The formula and method described in this embodiment couples the gasified slag with biomass to form a large-particle fuel with excellent strength and suitable size, which can be burned in a circulating fluidized bed boiler. The interaction between the gasified slag and the biomass in the coupled fuel is obvious. The biomass acts as a binder, so that the gasified slag can be pressed into particles, which greatly improves the situation where the gasified slag cannot be fully burned in the circulating fluidized bed boiler. In turn, the gasified slag can fix the alkali metal elements in the biomass, reducing the corrosion and coking effects on the boiler caused by the biomass blending.

[0038] See also Figure 1 The embodiment of the present invention discloses a system for preparing and utilizing coal gasification slag and biomass coupled fuel, including a pretreatment unit, a mixing and molding unit, and a combustion unit.

[0039] The pretreatment unit includes a first heat exchanger 31, a pulverizer 4 and a second heat exchanger 32; the coal gasification slag 1 is dried by the first heat exchanger 31 and then transported to the mixing and molding unit; the biomass 2 is sequentially transported to the mixing and molding unit after passing through the pulverizer 4 and the second heat exchanger 32; It should be noted that the heat exchanger is used for moisture control, the pulverizer 4 is mainly used for crushing the biomass 2, and the pretreatment unit ensures the strength performance of the fuel after molding.

[0040] The hybrid molding unit includes a feeder 5, a mixer 6 and a press 7 connected in sequence; the inlet of the mixer 6 is also connected to the outlets of the first heat exchanger 31 and the second heat exchanger 32; the outlet of the press 7 is connected to the combustion unit; It should be noted that the mixer 6 is used to mix the coal gasification slag 1 and the biomass 2 in a proportional and uniform manner, the press machine 7 is used to shape the coupling fuel, the feeder 5 is used to add the binder to the mixed material, and the mixing and molding unit is responsible for the preparation of the coupling fuel.

[0041] The combustion unit includes a storage bin 8, a fan 9, a furnace 11, a cyclone separator 12 and a material return mechanism 15; the inlet of the storage bin 8 is connected to the outlet of the forming press 7, and the outlet of the storage bin 8 is connected to the front end of the furnace 11; the fan 9 is installed at the front end of the furnace 11, and the tail end of the furnace 11 is connected to the cyclone separator 12; the bottom of the cyclone separator 12 is connected to the front end of the furnace 11 through the material return mechanism 15.

[0042] It should be noted that the storage bin 8 is used to store the prepared coupling fuel, the furnace 11 is the combustion area of ​​the coupling fuel, the cyclone separator 12 can separate the burned fuel 14 from the unburned fuel 13, and the return mechanism 15 is used to return the unburned fuel 13 to the furnace 11 for circulating combustion. The combustion unit is responsible for the combustion and heat generation of the coupling fuel.

[0043] In the combustion process of this embodiment, the particles burn from the outside to the inside, and the intensity of the burned part decreases and can be separated from the fuel particles. Figure 1 The burned fuel 14 part is discharged from the furnace with the flue gas through the cyclone separator, and the burning or unburned part still exists. It is not discharged with the flue gas when passing through the cyclone separator, but continues to return to the furnace for combustion. Figure 1 The unburned fuel 13 part is burned until it is completely burned, which increases the number of cycles and improves the economic efficiency of the unit operation.

[0044] In a feasible embodiment of the present invention, the hybrid molding unit further includes a heat recovery flue gas duct 17; the inlet of the heat recovery flue gas duct 17 is connected to the top of the cyclone separator 12, the first outlet of the heat recovery flue gas duct 17 is connected to the press 7, the second outlet of the heat recovery flue gas duct 17 is connected to the high temperature side inlet of the first heat exchanger 31, and the high temperature side outlet of the first heat exchanger 31 is connected to the high temperature side inlet of the second heat exchanger 32; a dust collector 16 is also installed at the inlet of the heat recovery flue gas duct 17. The heat source of the heat exchanger and the press 7 is the high temperature flue gas after the combustion of the coupled fuel, without the help of external energy.

[0045] In this embodiment, the high-temperature flue gas generated by the combustion provides a heat source for the production of the coupled fuel through the heat recovery flue gas duct 17. The fuel production stage does not require the use of an external heat source. A portion of the high-temperature flue gas generated by the combustion of the gasified slag and the biomass coupled fuel enters the heat recovery flue gas duct 17 and is then divided into two streams, which provide heat for the drying process of the gasified slag 1 and the biomass 2 and the fuel molding process, thereby greatly controlling the cost required for fuel production.

[0046] The working process / working principle of the system of the present invention is as follows: When biomass 2 is mixed and burned in the furnace, corrosion and coking will occur on the heating surfaces in the furnace. When gasified fine slag is mixed and burned, due to its small particle size, it will be discharged along with the flue gas through the cyclone separator 12 in the first cycle. Therefore, this embodiment proposes a coupling fuel of gasification slag and biomass and its utilization system. The coupling fuel has excellent strength and suitable size and can be burned in a circulating fluidized bed boiler. The preparation and combustion stages of the coupling fuel achieve energy reciprocity and reduce costs. The interaction between the gasification slag and biomass in the coupling fuel is obvious. The biomass acts as a binder, so that the gasification slag can be pressed into particles, which greatly improves the situation where the gasification slag cannot be fully burned in the circulating fluidized bed boiler. In turn, the gasification slag can fix the alkali metal elements in the biomass and reduce the corrosion and coking effects on the boiler caused by the mixing of biomass.

[0047] The gasification slag 1 enters the first heat exchanger 31, and after the moisture content is controlled at 15-30%, it enters the mixer 6 from the outlet of the first heat exchanger 31 through a conveyor belt; after the biomass 2 passes through the crusher 4, it enters the second heat exchanger 32 through a conveyor belt, and enters the mixer 6 without being completely dried; the proportions of the gasification slag 1 and the biomass 2 in the mixer are 50-75 parts and 25-50 parts respectively; the two materials evenly mixed by the mixer 6 enter the press 7, and are formed under a hot pressure of 100-250°C and 10-15MPa, and then enter the storage bin 8; the coupled fuel particles 10 enter the furnace 11 through a conveyor belt in the storage bin 8, and enter the cyclone separator 12 after being burned in the furnace 11, wherein the burned fuel 14 is discharged with the flue gas, and the unburned fuel 13 enters the return mechanism 15, and then returns to the furnace 11 to continue burning, and is consistent with the previous process, and is circulated multiple times until it is burned out. After passing through the filter 16, part of the high-temperature flue gas generated by combustion enters the high-temperature flue gas heat recovery pipe and is divided into two streams. One stream is passed into the first heat exchanger 31. After the moisture content of the gasified slag is controlled in the first heat exchanger 31, the flue gas temperature is reduced and then passed into the second heat exchanger 32 to dry the biomass. Since the biomass does not need to be completely dried, the flue gas drawn from the first heat exchanger 31 can be directly used; the other high-temperature flue gas in the high-temperature flue gas heat recovery pipe 17 is passed into the molding machine 7 to heat the mold in the molding machine 7 and provide heat for the coupling of the gasified slag and the biomass. According to this process flow, no external energy is required in the production process of the coupled fuel.

[0048] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0049] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0050] Embodiment 1: The coupling fuel in this embodiment is composed of 30 parts of biomass, 60 parts of coal gasification fine slag and 8 parts of binder; First, the coal gasification slag is dried to a moisture content of 22% and an average particle size of 170 μm; the biomass is dried and crushed to a moisture content of 16% and an average particle size of 106 meshes.

[0051] After the coal gasification slag, biomass and binder are mixed and stirred evenly, the coupling fuel is obtained by pressing with a hot press. The molding temperature during the molding process is 100°C and the molding pressure is 10MPa. The size of the finally obtained coupling fuel is 10mm in diameter and 6mm in height.

[0052] Embodiment 2: The coupling fuel in this embodiment is composed of 25 parts of biomass, 55 parts of coal gasification fine slag and 5 parts of binder; First, the coal gasification slag is dried to a moisture content of 21% and an average particle size of 177 μm; the biomass is dried and crushed to a moisture content of 17% and an average particle size of 110 meshes.

[0053] After the coal gasification slag, biomass and binder are mixed and stirred evenly, the coupling fuel is obtained by pressing with a hot press. The molding temperature during the molding process is 150°C and the molding pressure is 5MPa. The size of the finally obtained coupling fuel is 12mm in diameter and 8mm in height.

[0054] Embodiment 3: The coupling fuel in this embodiment is composed of 35 parts of biomass, 50 parts of coal gasification fine slag and 8 parts of binder; First, the coal gasification slag is dried to a moisture content of 16% and an average particle size of 160 μm; the biomass is dried and crushed to a moisture content of 16% and an average particle size of 120 meshes.

[0055] After the coal gasification slag, biomass and binder are mixed and stirred evenly, the coupling fuel is obtained by pressing with a hot press. The molding temperature during the molding process is 200°C and the molding pressure is 15MPa. The size of the finally obtained coupling fuel is 14mm in diameter and 7mm in height.

[0056] Embodiment 4: The coupling fuel in this embodiment is composed of 40 parts of biomass, 65 parts of coal gasification fine slag and 9 parts of binder; First, the coal gasification slag is dried to a moisture content of 25% and an average particle size of 164 μm; the biomass is dried and crushed to a moisture content of 18% and an average particle size of 114 meshes.

[0057] After the coal gasification slag, biomass and binder are mixed and stirred evenly, the coupling fuel is obtained by pressing with a hot press. The molding temperature during the molding process is 250°C and the molding pressure is 20MPa. The size of the finally obtained coupling fuel is 15mm in diameter and 9mm in height.

[0058] Embodiment 5: The coupling fuel in this embodiment is composed of 45 parts of biomass, 70 parts of coal gasification fine slag and 10 parts of binder; First, the coal gasification slag is dried to a moisture content of 26% and an average particle size of 164 μm; the biomass is dried and crushed to a moisture content of 13% and an average particle size of 110 meshes.

[0059] After the coal gasification slag, biomass and binder are mixed and stirred evenly, the coupling fuel is obtained by pressing with a hot press. The molding temperature during the molding process is 250°C and the molding pressure is 25MPa. The size of the finally obtained coupling fuel is 12mm in diameter and 5mm in height.

[0060] 1) Strength test In order to ensure the quality of the coupled fuel products, a universal tester was used to perform strength tests on the coupled fuel products prepared in Examples 1 to 5.

[0061] Depend on Figure 2 The compressive strength of the coupled fuel at different molding temperatures was obtained. The maximum compressive strength of the prepared coupled fuel can reach 10.5 kN at 200 °C, and the compressive strength of the coupled fuel at the molding temperature of 100-200 °C is higher than that of other working conditions, especially much greater than the compressive strength during cold pressing.

[0062] Depend on Figure 3 The compressive strength of the coupled fuel under different molding pressures was obtained. The compressive strength of the prepared coupled fuel under molding pressures of 5-25 MPa was between 9.8 kN and 11 kN, which met the actual application requirements.

[0063] 2) Combustion weight loss test In order to ensure the quality of the coupled fuel products, the combustion properties of the coupled fuel were tested using a self-built large-scale flat flame thermogravimetric test bench. The large-scale flat flame thermogravimetric test bench uses high-temperature flue gas to heat and ignite the coupled fuel, fully simulating the actual combustion of the coupled fuel in the furnace, ensuring that the data has guiding significance for industrial production activities.

[0064] Depend on Figure 4 and Figure 5 The weight loss data of the coupled fuel under different molding temperatures and different molding pressures were obtained. Under air atmosphere, the volatile matter of the coupled fuel precipitated rapidly after heating began, and the weight dropped rapidly. All the volatile matter precipitated and burned within 200 seconds, entering the coke combustion stage. The weight loss rate decreased significantly until the reaction stopped and the combustion was completed at 1000 seconds.

[0065] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A coal gasification slag and biomass coupling fuel, characterized in that: Calculated by weight, the components include 25-50 parts of biomass, 50-70 parts of coal gasification slag, and 5-10 parts of binder.

2. The coal gasification slag and biomass coupled fuel according to claim 1, characterized in that: The biomass is a mixture of one or more of seabuckthorn, salix psammophila, wormwood and spatholobi; and the coal gasification slag is coal-water slurry furnace gasification slag.

3. The coal gasification slag and biomass coupled fuel according to claim 1, characterized in that: The binder comprises, by weight, 1 to 2 parts of kaolin, 3 to 8 parts of coal tar, and 1 to 2 parts of starch.

4. A method for preparing the coal gasification slag and biomass coupled fuel according to any one of claims 1 to 3, characterized in that: The following steps are involved: The coal gasification slag and biomass are pre-treated separately, mixed after reaching the preset moisture content and particle size, and then a binder is added and stirred; The stirred mixture is pressed by a hot press to obtain a coupling fuel of a preset size.

5. The method for preparing a coal gasification slag and biomass coupled fuel according to claim 4, characterized in that: The water content of the coal gasification slag after pretreatment is 15%-30%, and the particle size is less than 180 μm.

6. The method for preparing a coal gasification slag and biomass coupled fuel according to claim 4, characterized in that: The water content of the biomass after pretreatment is 10% to 20%, and the particle size is greater than 100 meshes.

7. The method for preparing a coal gasification slag and biomass coupled fuel according to claim 4, characterized in that: The temperature during the hot press molding process is 100°C to 250°C, and the molding pressure is 5 MPa to 25 MPa.

8. The method for preparing a coal gasification slag and biomass coupled fuel according to claim 4, characterized in that: The coupling fuel of the preset size is cylindrical, with a diameter of 10 mm to 15 mm and a height of 5 mm to 10 mm.

9. A system for preparing and utilizing coal gasification slag and biomass coupled fuel, characterized in that: A method for preparing a coal gasification slag and biomass coupled fuel according to any one of claims 4 to 8, comprising: A pretreatment unit, the pretreatment unit comprising a first heat exchanger (31), a pulverizer (4) and a second heat exchanger (32); the coal gasification slag (1) is dried by the first heat exchanger (31) and then transported to the mixing and molding unit; the biomass (2) passes through the pulverizer (4) and the second heat exchanger (32) in sequence and then transported to the mixing and molding unit; A mixed molding unit, the mixed molding unit comprising a feeder (5), a mixer (6) and a press (7) connected in sequence; the inlet of the mixer (6) is also connected to the outlets of the first heat exchanger (31) and the second heat exchanger (32); the outlet of the press (7) is connected to the combustion unit; A combustion unit, the combustion unit comprising a material storage bin (8), a fan (9), a furnace (11), a cyclone separator (12) and a material return mechanism (15); the inlet of the material storage bin (8) is connected to the outlet of a forming machine (7), and the outlet of the material storage bin (8) is connected to the front end of the furnace (11); the fan (9) is installed at the front end of the furnace (11), and the rear end of the furnace (11) is connected to the cyclone separator (12); the bottom of the cyclone separator (12) is connected to the front end of the furnace (11) through the material return mechanism (15).

10. A system for preparing and utilizing coal gasification slag and biomass coupled fuel according to claim 9, characterized in that: The mixed molding unit further comprises a heat recovery flue gas duct (17); the inlet of the heat recovery flue gas duct (17) is connected to the top of the cyclone separator (12); the first outlet of the heat recovery flue gas duct (17) is connected to the molding machine (7); the second outlet of the heat recovery flue gas duct (17) is connected to the high-temperature side inlet of the first heat exchanger (31); the high-temperature side outlet of the first heat exchanger (31) is connected to the high-temperature side inlet of the second heat exchanger (32); and a dust collector (16) is also installed at the inlet of the heat recovery flue gas duct (17).

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