Device and method for preparing briquette fuel from lignite by coupling double heat sources of coal-fired power plant

Abstract

The invention provides a device and method for preparing briquette fuel from lignite by coupling double heat sources of a coal-fired power plant, the device comprises a pre-dryer, a first dust remover, a fluidized bed upgrading reactor, a second dust remover and a coal mill, the heat source of the pre-dryer is from steam of the coal-fired power plant, and the heat source of the fluidized bed upgrading reactor is from flue gas of a coal-fired boiler. Pulverized coal ground by the coal mill and pulverized coal captured by the first dust remover and the second dust remover are fed into a coal-fired boiler to be combusted or fed into a finished coal preparation device to prepare finished coal. According to the invention, steam and flue gas from a coal-fired power plant are fully utilized, carbon emission of unit calorific value fuel is reduced, and low-carbon emission reduction is realized. Steam and flue gas are used for heating and drying the lignite, the moisture content of the lignite can be reduced, the heat value can be increased, and higher efficiency is achieved when the lignite is blended and burnt in a coal-fired power plant. And the pulverized coal is conveyed into the finished coal preparation device to prepare finished coal suitable for outward transportation, so that the transportation cost of the lignite can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of lignite preparation and low-carbon emission reduction, and in particular to a device and method for preparing shaped fuel from lignite by coupling dual heat sources of a coal-fired power plant. Background Art

[0002] Lignite is one of the four major types of coal in my country. In the lignite producing areas in northern my country and the southeastern coastal areas, lignite has become one of the main coals used for power generation due to its cost advantage. Although lignite has the advantage of low cost, it is expensive to transport inland due to its high moisture content, low calorific value, and flammability. In addition, the flue gas and steam discharged from coal-fired power plants have high heat and are usually not effectively utilized. If they are discharged directly into the atmosphere, they will cause air pollution on the one hand and energy loss on the other. Therefore, how to use the flue gas and steam discharged from coal-fired power plants to prepare finished coal with low moisture content, high calorific value, and suitable for external transportation is a topic that urgently needs to be studied. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the embodiment of the present invention provides a device and method for preparing shaped fuel from lignite by coupling the dual heat sources of a coal-fired power plant, which can not only achieve higher efficiency when the coal-fired power plant is mixed with lignite, but also prepare finished coal with low moisture content, high calorific value and suitable for external transportation, thereby reducing the carbon emission of fuel per unit calorific value.

[0004] In one aspect, an embodiment of the present invention proposes a device for preparing shaped fuel from lignite by coupling dual heat sources of a coal-fired power plant, comprising: a predryer, a first dust collector, a fluidized bed upgrading reactor, a second dust collector and a coal pulverizer.

[0005] The predryer comprises a first drying chamber and a first wind chamber which are connected to each other. The first drying chamber comprises a material inlet and an exhaust port. A heating coil is arranged inside the first drying chamber. Steam from a coal-fired power plant is introduced into the heating coil. The first wind chamber is located at the bottom of the first drying chamber. The first wind chamber comprises an air inlet and a material outlet. The air inlet of the first wind chamber is connected to the air outlet of the first fan. The material outlet of the first wind chamber is located at the bottom of the first wind chamber and is provided with an openable and closable gate.

[0006] The first dust collector separates the gas, water and coal powder discharged from the pre-dryer, and the dust discharge port of the first dust collector is respectively connected to the coal-fired boiler and the finished coal preparation device.

[0007] The fluidized bed upgrading reactor comprises a second drying chamber and a second wind chamber which are connected to each other. The second drying chamber comprises a feed port and an exhaust port. The feed port of the second drying chamber is connected to the discharge port of the first wind chamber. The second wind chamber is located at the bottom of the second drying chamber. The second wind chamber comprises an air inlet and a discharge port. The air inlet of the second wind chamber is connected to the air outlet of the second fan. The second fan transports the smoke of the coal-fired boiler to the second wind chamber. The discharge port of the second wind chamber is located at the bottom of the second wind chamber and is provided with an openable and closable gate.

[0008] The second dust collector separates gas, water and coal powder discharged from the fluidized bed upgrading reactor, and the dust discharge port of the second dust collector is respectively connected to the coal-fired boiler and the finished coal preparation device.

[0009] The coal mill is arranged at the discharge port of the second wind chamber to grind the lump lignite dried by the fluidized bed upgrading reactor into coal powder. The coal discharge port of the coal mill is respectively connected to the coal-fired boiler and the finished coal preparation device.

[0010] In some embodiments, the finished coal preparation device includes an agitator, a mixer and an extruder. The mixer has a first feed port, a second feed port and a discharge port. The first feed port is connected to the agitator, and the agitator is used to evenly mix the raw materials for preparing the finished coal. The second feed port is respectively connected to the coal discharge port of the pulverizer, the dust discharge port of the first dust collector and the dust discharge port of the second dust collector, and is used to pass coal powder into the mixer. The extruder is connected to the discharge port of the mixer to extrude the mixed raw materials and coal powder into shape.

[0011] In some embodiments, the first dust collector has an air inlet, a dust exhaust port and an exhaust port, the air inlet of the first dust collector is connected to the exhaust port of the pre-dryer, the exhaust port of the first dust collector is connected to the air inlet of the first fan, and the dust exhaust port of the first dust collector is respectively connected to the second feed port of the mixer and the coal-fired boiler.

[0012] The second dust collector has an air inlet, a dust outlet and an exhaust port. The air inlet of the second dust collector is connected to the exhaust port of the fluidized bed upgrading reactor, the exhaust port of the second dust collector is connected to the coal-fired boiler, and the dust outlet of the second dust collector is respectively connected to the second feed port of the mixer and the coal-fired boiler.

[0013] In some embodiments, the feed inlet of the fluidized bed upgrading reactor is located above the second wind chamber and close to the second wind chamber.

[0014] In some embodiments, the device for coupling the dual heat sources of a coal-fired power plant to prepare molded fuel from lignite also includes a raw coal crusher, which has a feed port and a discharge port. The feed port of the raw coal crusher is connected to a raw coal bin, and the discharge port of the raw coal crusher is connected to the feed port of a pre-dryer.

[0015] In some embodiments, the device for coupling the dual heat sources of a coal-fired power plant to prepare molded fuel from lignite also includes a heat exchanger, wherein the heat exchanger has a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet, the tube side inlet is connected to the exhaust port of a first dust collector, the water discharged from the tube side outlet is recovered, condensate is introduced into the shell side inlet, the shell side outlet is connected to the shell side inlet through a circulation pipeline, and the circulation pipeline is connected to the first low-pressure heater to pass the heated condensate into the first low-pressure heater for utilization.

[0016] In some embodiments, the device for coupling the dual heat sources of a coal-fired power plant to prepare molded fuel from lignite also includes a steam turbine, wherein the steam turbine has an air inlet and an air outlet, and steam from the coal-fired power plant is introduced into the steam turbine through the air inlet of the steam turbine, and the air outlet of the steam turbine is connected to the air inlet of the heating coil through an air inlet pipe, and the air outlet of the heating coil is connected to the deaerator through an air outlet pipe.

[0017] The circulation pipeline is connected with a branch pipe and connected to a deaerator through the branch pipe to deoxygenate the condensate after heat exchange. The branch pipe is connected to a second low-pressure heater to pass the heated condensate into the second low-pressure heater for utilization.

[0018] The air inlet pipe is connected with a bypass, and the bypass is connected with the air inlet of the first air chamber.

[0019] In some embodiments, a coal cooler is connected between the second wind chamber and the coal mill to cool the lump lignite.

[0020] Another embodiment of the present invention provides a method for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant, using the above-mentioned device, including the following steps:

[0021] The lignite in the raw coal bin is crushed by the raw coal crusher and then enters the pre-dryer. The steam from the coal-fired power plant is passed through the steam turbine to the heating coil in the pre-dryer to pre-dry the crushed lignite. The first fan is started to evenly distribute the heat in the pre-dryer. The dried coal powder and gas and water enter the first dust collector for separation. Part of the separated coal powder is passed into the coal-fired boiler for combustion, and the rest of the coal powder is passed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal. Part of the separated gas and water is passed into the heat exchanger to utilize the heat of the gas and water, and the rest of the gas and water is sent to the pre-dryer through the first fan for gas-water circulation.

[0022] The pre-dried lump lignite enters the fluidized bed upgrading reactor, and the high-temperature flue gas of 300-500°C is extracted from the tail flue of the coal-fired boiler, pressurized by the second fan, and then sent into the fluidized bed upgrading reactor through the second wind chamber, where the lump lignite is further heated and dried. The dried coal powder and gas and water enter the second dust collector for separation. Part of the separated coal powder is passed into the coal-fired boiler for combustion, and the rest of the coal powder is passed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal. The separated gas and water are passed into the coal-fired boiler for combustion.

[0023] The lump lignite that has not yet dried into coal powder in the fluidized bed upgrading reactor is cooled and then fed into a coal pulverizer to be ground into coal powder. A portion of the coal powder is passed into a coal-fired boiler for combustion, and the rest of the coal powder is passed into a finished coal preparation device to be mixed with the raw materials to prepare finished coal.

[0024] In some embodiments, the raw materials include any one of asphalt and tar, any one of water and organic wastewater, and an emulsifier, and the mass ratio of any one of asphalt and tar, any one of water or organic wastewater, emulsifier and coal powder is 0.5~2.5:0.2~2:0.004~0.02:10. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0026] in:

[0027] Figure 1 It is a schematic structural diagram of a device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant in an embodiment of the present invention;

[0028] Reference numerals:

[0029] 1. Pre-dryer; 101. First wind chamber; 2. Fluidized bed upgrading reactor; 201. Second wind chamber; 3. Coal-fired boiler; 4. Raw coal bin; 5. Raw coal crusher; 6. First dust collector; 7. Steam turbine; 8. Heating coil; 9. Rotary feeder; 10. First fan; 11. Second dust collector; 12. Second fan; 13. Coal cooler; 14. Coal mill; 15. Heat exchanger; 16. Condensate pump; 17. First low-pressure heater; 18. Second low-pressure heater; 19. Bypass; 20. Agitator; 21. Mixer; 22. Extruder. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0031] The following describes, with reference to the accompanying drawings, an apparatus and method for preparing molded fuel from lignite by coupling dual heat sources of a coal-fired power plant according to an embodiment of the present invention.

[0032] like Figure 1 As shown, an embodiment of the present invention proposes a device for preparing shaped fuel from lignite by coupling dual heat sources of a coal-fired power plant, comprising: a predryer 1, a first dust collector 6, a fluidized bed upgrading reactor 2, a second dust collector 11 and a coal pulverizer 14.

[0033] The predryer 1 has a first drying chamber and a first wind chamber 101 which are connected to each other. The first drying chamber has a feed port and an exhaust port. A heating coil 8 is arranged inside the first drying chamber. Steam from a coal-fired power plant is introduced into the heating coil 8. The first wind chamber 101 is located at the bottom of the first drying chamber. The first wind chamber 101 has an air inlet and an outlet. The air inlet of the first wind chamber 101 is connected to the air outlet of the first fan 10. The outlet of the first wind chamber 101 is located at the bottom of the first wind chamber 101 and is provided with an openable and closable gate.

[0034] The first dust collector 6 separates the gas, water and coal powder discharged from the pre-dryer 1, and the dust discharge port of the first dust collector 6 is connected to the coal-fired boiler 3 and the finished coal preparation device respectively.

[0035] The fluidized bed upgrading reactor 2 has a second drying chamber and a second wind chamber 201 that are connected. The second drying chamber has a feed port and an exhaust port. The feed port of the second drying chamber is connected to the discharge port of the first wind chamber 101. The second wind chamber 201 is located at the bottom of the second drying chamber. The second wind chamber 201 has an air inlet and a discharge port. The air inlet of the second wind chamber 201 is connected to the air outlet of the second fan 12. The second fan 12 transports the flue gas of the coal-fired boiler 3 to the second wind chamber 201. The discharge port of the second wind chamber 201 is located at the bottom of the second wind chamber 201 and is provided with an openable and closable gate.

[0036] The second dust collector 11 separates the gas, water and coal powder discharged from the fluidized bed upgrading reactor 2, and the dust discharge port of the second dust collector 11 is connected to the coal-fired boiler 3 and the finished coal preparation device respectively.

[0037] The coal mill 14 is disposed at the discharge port of the second wind chamber 201 to grind the lump lignite dried by the fluidized bed upgrading reactor 2 into coal powder. The coal discharge port of the coal mill 14 is respectively connected to the coal-fired boiler 3 and the finished coal preparation device.

[0038] The embodiment of the present invention makes full use of steam and flue gas from coal-fired power plants by providing a predryer 1, a fluidized bed upgrading reactor 2, a coal mill 14 and a finished coal preparation device, thereby reducing carbon emissions per unit calorific value of fuel and achieving low-carbon emission reduction. Steam and flue gas are used to heat and dry lignite, which can reduce the moisture content of lignite, increase the calorific value, and achieve higher efficiency when coal-fired power plants burn lignite. The lignite is ground into powder by the coal mill 14 and transported to the finished coal preparation device to prepare finished coal suitable for external transportation, which can reduce the transportation cost of lignite.

[0039] By setting the first wind chamber 101 and the second wind chamber 201, on the one hand, a hot air flow from bottom to top is formed in the first drying chamber and the second drying chamber to heat the lignite, providing power for the coal powder in the lignite to be discharged to the first dust collector 6 and the second dust collector 11 through the exhaust port; on the other hand, the heat distribution in the predryer 1 and the fluidized bed upgrading reactor 2 can be uniform, so that the lignite can be dried faster and more evenly.

[0040] By setting the first dust collector 6 and the second dust collector 11, the gas-water discharged from the predryer 1 and the fluidized bed upgrading reactor 2 can be separated from the coal powder and used separately, wherein the high-temperature gas-water can be used for heat exchange and to provide power for pneumatic conveying, and the water obtained after further separation of the gas-water can be recycled. The high-temperature gas-water separated by the first dust collector 6 and the second dust collector 11 can also be pressurized by the first fan 10 and the second fan 12 and returned to the predryer 1 and the fluidized bed upgrading reactor 2 for circulation, so as to realize the fluidization of the lignite inside the predryer 1 and the fluidized bed upgrading reactor 2. The coal powder separated by the first dust collector 6 and the second dust collector 11 can be introduced into the coal-fired boiler 3 for combustion as fuel, and can also be introduced into the finished coal preparation device to prepare finished coal.

[0041] Furthermore, the first dust collector 6 and the second dust collector 11 are cyclone dust collectors or electrostatic dust collectors, preferably cyclone dust collectors, which have higher dust removal and separation efficiency.

[0042] In some embodiments, the finished coal preparation device includes an agitator 20, a mixer 21 and an extruder 22. The mixer 21 has a first feed port, a second feed port and a discharge port. The first feed port is connected to the agitator 20. The agitator 20 is used to evenly mix the raw materials for preparing the finished coal. The second feed port is respectively connected to the coal discharge port of the pulverizer 14, the dust discharge port of the first dust collector 6 and the dust discharge port of the second dust collector 11, and is used to pass coal powder into the mixer 21. The extruder 22 is connected to the discharge port of the mixer 21 to extrude the mixed raw materials and coal powder into shape.

[0043] In some embodiments, the first dust collector 6 has an air inlet, a dust exhaust port and an exhaust port. The air inlet of the first dust collector 6 is connected to the exhaust port of the pre-dryer 1, the exhaust port of the first dust collector 6 is connected to the air inlet of the first fan 10, and the dust exhaust port of the first dust collector 6 is respectively connected to the second feed port of the mixer 21 and the coal-fired boiler 3.

[0044] The second dust collector 11 has an air inlet, a dust outlet and an exhaust port. The air inlet of the second dust collector 11 is connected to the exhaust port of the fluidized bed upgrading reactor 2, the exhaust port of the second dust collector 11 is connected to the coal-fired boiler 3, and the dust outlet of the second dust collector 11 is respectively connected to the second feed port of the mixer 21 and the coal-fired boiler 3.

[0045] In some embodiments, the feed inlet of the fluidized bed upgrading reactor 2 is located above the second wind chamber 201 and close to the second wind chamber 201 .

[0046] Since the exhaust port of the fluidized bed upgrading reactor 2 is located at the top of the fluidized bed upgrading reactor 2, arranging the feed port at a position far away from the exhaust port can extend the movement distance of the coal powder, thereby extending the drying time and making the coal powder fully dry.

[0047] In some embodiments, the device for coupling the dual heat sources of a coal-fired power plant to prepare molded fuel from lignite also includes a raw coal crusher 5, which has a feed port and a discharge port. The feed port of the raw coal crusher 5 is connected to the raw coal bin 4, and the discharge port of the raw coal crusher 5 is connected to the feed port of the pre-dryer 1.

[0048] The raw coal is broken into small pieces to facilitate full drying and subsequent grinding into powder and sent to the coal-fired boiler 3 for combustion, thereby improving combustion efficiency and facilitating the preparation of finished coal.

[0049] Furthermore, a rotary feeder 9 is connected to the feed inlet of the pre-dryer 1, and the rotary feeder 9 is located in the first drying chamber, so that the crushed lump lignite can be evenly dropped in the first drying chamber.

[0050] In some embodiments, the device for coupling the dual heat sources of a coal-fired power plant to prepare molded fuel from lignite also includes a heat exchanger 15, which has a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet. The tube side inlet is connected to the exhaust port of the first dust collector 6, and the water discharged from the tube side outlet is recovered. Condensate is introduced into the shell side inlet, and the shell side outlet is connected to the shell side inlet through a circulation pipeline. The circulation pipeline is connected to the first low-pressure heater 17 to pass the heated condensate into the first low-pressure heater 17 for utilization, thereby realizing heat recovery.

[0051] In some embodiments, the device for coupling the dual heat sources of a coal-fired power plant to prepare molded fuel from lignite also includes a steam turbine 7, which has an air inlet and an air outlet. Steam from the coal-fired power plant is introduced into the steam turbine 7 through the air inlet of the steam turbine 7, and the air outlet of the steam turbine 7 is connected to the air inlet of the heating coil 8 through an air inlet pipe, and the air outlet of the heating coil 8 is connected to the deaerator through an air outlet pipe.

[0052] The circulation pipeline is connected with a branch pipe and connected to a deaerator through the branch pipe to deoxygenate the condensate after heat exchange. The branch pipe is connected to a second low-pressure heater 18 to pass the heated condensate into the second low-pressure heater 18 for utilization.

[0053] The air inlet pipe is connected with a bypass 19 , and the bypass 19 is connected with the air inlet of the first air chamber 101 .

[0054] During the startup phase of the predryer 1, since the air-water circulation cannot be established, the steam delivered by the steam turbine 7 is directly sent to the first wind chamber 101 of the predryer 1 by starting the bypass 19 to heat the first drying chamber, and the material is gradually added to establish the circulation.

[0055] Furthermore, a valve is provided on the bypass 19 .

[0056] In some embodiments, a coal cooler 13 is connected between the second wind chamber 201 and the coal mill 14 to cool the lump lignite.

[0057] Furthermore, humidity monitoring devices are respectively provided at the exhaust port of the predryer 1 and the exhaust port of the fluidized bed upgrading reactor 2 to monitor the humidity of the exhausted gas. When the humidity of the predryer 1 reaches the requirement, the gate of the first wind chamber 101 is opened to discharge the lignite into the fluidized bed upgrading reactor 2. When the humidity of the fluidized bed upgrading reactor 2 reaches the requirement, the gate of the second wind chamber 201 is opened to discharge the lignite into the coal cooler 13.

[0058] Another embodiment of the present invention provides a method for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant, using the above-mentioned device, such as Figure 1 As shown, the following steps are included:

[0059] The lignite in the raw coal bin 4 is crushed by the raw coal crusher 5 and then enters the predryer 1. The steam of the coal-fired power plant is passed through the steam turbine 7 to the heating coil 8 in the predryer 1 to predry the crushed lignite. The first fan 10 is started to evenly distribute the heat in the predryer 1. The dried coal powder and gas-water enter the first dust collector 6 for separation. A part of the separated coal powder is passed into the coal-fired boiler 3 for combustion, and the rest of the coal powder is passed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal. A part of the separated gas-water is passed into the heat exchanger 15 to utilize the heat of the gas-water, and the rest of the gas-water is pressurized by the first fan 10 and sent to the predryer 1 for gas-water circulation, thereby improving the heat and mass transfer efficiency of the lignite in the predryer 1.

[0060] The pre-dried lump lignite enters the fluidized bed upgrading reactor 2, and the high-temperature flue gas of 300-500°C is extracted from the tail flue of the coal-fired boiler 3, and after dust removal and pressurization by the second fan 12, it is sent to the fluidized bed upgrading reactor 2 through the second wind chamber 201, and the lump lignite is further heated and dried, and fluidized under the action of the high-temperature flue gas, and further upgraded, achieving complete dehydration and releasing part of the volatile matter, and improving the calorific value of the lignite. A part of the released volatile matter reacts with a small amount of oxygen in the flue gas at high temperature to release heat, further providing the heat required for water vaporization and maintaining the temperature of the fluidized bed upgrading reactor 2.

[0061] The dried coal powder and gas and water enter the second dust collector 11 for separation. A part of the separated coal powder is passed into the coal-fired boiler 3 for combustion, and the rest of the coal powder is passed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal. The separated gas and water are passed into the coal-fired boiler 3 for combustion.

[0062] The lump lignite that has not yet been dried into coal powder in the fluidized bed upgrading reactor 2 is discharged from the bottom and enters the coal cooler 13 for cooling. The sensible heat of the dried coal is recovered by condensed water and then enters the coal pulverizer 14 to be ground into coal powder. A portion of the coal powder is passed into the coal-fired boiler 3 for combustion, and the rest of the coal powder is passed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal.

[0063] Through the above method, lignite is heated, dried and upgraded at temperatures of 200-300°C and 300-500°C, respectively, and the final products include: (1) water formed by pre-drying evaporation and condensation through a heat exchanger 15, thereby realizing water recovery in the coal, and since the pre-drying temperature is low at this time, there is no tar problem; (2) gas containing a small amount of coal powder (which cannot be captured by the dust collector) and volatile matter formed after drying and upgrading in the fluidized bed upgrading reactor 2 is recycled to the coal boiler 3 for combustion and utilization; (3) three-path coal powder: the first path is the pre-dried coal powder captured by the first dust collector 6 after pre-drying, the second path is the upgraded coal powder ground by the coal mill 14 after upgrading, and the third path is the upgraded coal powder captured by the second dust collector 11 after upgrading. Part of the three-path coal powder is recycled to the coal boiler 3 for combustion and utilization, and the other part enters the finished coal preparation device.

[0064] The moisture content of the finished coal prepared by the above method can be reduced from 30-60% of the original raw coal to below 5%, while releasing some volatile matter and reacting with oxygen. A part of the dried and upgraded lignite is directly put into the furnace for combustion, and the NOx concentration of the coal-fired boiler 3 is reduced by flue gas recirculation; the other part is used to prepare finished coal, which can greatly increase the density of the finished coal, reduce the risk of pulverization and spontaneous combustion during transportation, and facilitate external sales, and its characteristics can reach the level of bituminous coal.

[0065] Furthermore, a part of the gas and water separated by the first dust collector 6 is passed into the tube side of the heat exchanger 15 for heat exchange, and the shell side of the heat exchanger 15 is passed into the low-temperature condensed water at the outlet of the condensate pump 16 to reduce the temperature of the gas and water so that all the water is condensed, thereby realizing the recovery of water in the coal; after the low-temperature condensed water is heated, it enters the low-pressure heater of the unit for utilization, thereby realizing heat recovery.

[0066] Furthermore, the lignite is crushed by the raw coal crusher 5 to form lump coal with a particle size less than 5 mm.

[0067] Furthermore, the temperature of the steam in the coal-fired power plant is 200-300°C. After heat exchange with the lignite in the pre-dryer 1, the lignite is heated to 100-200°C, and the steam condenses into high-temperature water at 80-150°C. The high-temperature water is passed into the deaerator for deoxygenation and then recycled.

[0068] Furthermore, the coal powder ground by the coal mill 14 and the coal powder separated by the first dust collector 6 and the second dust collector 11 are divided into two paths, one of which is transported to the coal-fired boiler 3 for combustion by pneumatic conveying, and the other enters the mixer 21 of the finished coal preparation device by spiral feeding.

[0069] In some embodiments, the raw materials include any one of asphalt and tar, any one of water and organic wastewater, and an emulsifier, and the mass ratio between any one of asphalt and tar, any one of water or organic wastewater, emulsifier and coal powder is 0.5~2.5:0.2~2:0.004~0.02:10.

[0070] After the coal powder separated by grinding and dust collector is evenly mixed with asphalt / tar, water / organic wastewater and emulsifier in this proportion, the micropores and active surfaces formed after the lignite is dried and upgraded are blocked and passivated, and extruded under the bonding effect of asphalt / tar, which can greatly increase the density of the finished coal, reduce the risk of pulverization and spontaneous combustion during transportation, and facilitate external sales. Its characteristics can reach the level of bituminous coal. And the characteristics of the molded fuel are easy to adjust. At the same time, it can also achieve coupled disposal of organic wastewater.

[0071] Furthermore, the finished coal preparation device includes an agitator 20, a mixer 21 and an extruder 22. Any one of asphalt and tar, any one of water and organic wastewater and an emulsifier are mixed and homogenized in the agitator 20, and then enter the mixer 21, and after being evenly mixed with dried and upgraded coal powder in proportion, it is extruded and formed by the extruder 22 to form granular finished coal.

[0072] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0074] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0076] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0077] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant, characterized in that: include: A predryer, the predryer having a first drying chamber and a first wind chamber connected to each other, the first drying chamber having a feed inlet and an exhaust port, a heating coil being arranged inside the first drying chamber, steam from a coal-fired power plant being introduced into the heating coil, the first wind chamber being located at the bottom of the first drying chamber, the first wind chamber having an air inlet and an outlet, the air inlet of the first wind chamber being connected to the air outlet of a first fan, the outlet of the first wind chamber being located at the bottom of the first wind chamber and being provided with an openable and closable gate; A first dust collector, wherein the first dust collector separates gas, water and coal powder discharged from the pre-dryer, and a dust discharge port of the first dust collector is respectively connected to a coal-fired boiler and a finished coal preparation device; A fluidized bed upgrading reactor, wherein the fluidized bed upgrading reactor has a second drying chamber and a second wind chamber connected to each other, the second drying chamber has a feed inlet and an exhaust port, the feed inlet of the second drying chamber is connected to the discharge port of the first wind chamber, the second wind chamber is located at the bottom of the second drying chamber, the second wind chamber has an air inlet and a discharge port, the air inlet of the second wind chamber is connected to the air outlet of a second fan, the second fan transports the flue gas of the coal-fired boiler to the second wind chamber, the discharge port of the second wind chamber is located at the bottom of the second wind chamber and is provided with an openable and closable gate; A second dust collector, the second dust collector separates gas, water and coal powder discharged from the fluidized bed upgrading reactor, and the dust discharge port of the second dust collector is respectively connected to the coal-fired boiler and the finished coal preparation device; A coal mill is arranged at the discharge port of the second wind chamber to grind the lump lignite dried by the fluidized bed upgrading reactor into coal powder, and the coal outlet of the coal mill is respectively connected to the coal-fired boiler and the finished coal preparation device.

2. The device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant according to claim 1 is characterized in that: The finished coal preparation device includes an agitator, a mixer and an extruder. The mixer has a first feed port, a second feed port and a discharge port. The first feed port is connected to the agitator, and the agitator is used to evenly stir the raw materials for preparing the finished coal. The second feed port is respectively connected to the coal discharge port of the pulverizer, the dust discharge port of the first dust collector and the dust discharge port of the second dust collector, and is used to introduce coal powder into the mixer. The extruder is connected to the discharge port of the mixer to extrude the mixed raw materials and coal powder into shape.

3. The device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant according to claim 2 is characterized in that: The first dust collector has an air inlet, a dust outlet and an exhaust port, the air inlet of the first dust collector is connected to the exhaust port of the pre-dryer, the exhaust port of the first dust collector is connected to the air inlet of the first fan, and the dust outlet of the first dust collector is respectively connected to the second feed port of the mixer and the coal-fired boiler; The second dust collector has an air inlet, a dust outlet and an exhaust port. The air inlet of the second dust collector is connected to the exhaust port of the fluidized bed upgrading reactor, the exhaust port of the second dust collector is connected to the coal-fired boiler, and the dust outlet of the second dust collector is respectively connected to the second feed port of the mixer and the coal-fired boiler.

4. The device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant according to claim 1 is characterized in that: The feed inlet of the fluidized bed upgrading reactor is located above the second wind chamber and close to the second wind chamber.

5. The device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant according to claim 1 is characterized in that: It also includes a raw coal crusher, which has a feed port and a discharge port. The feed port of the raw coal crusher is connected to a raw coal bin, and the discharge port of the raw coal crusher is connected to the feed port of the pre-dryer.

6. The device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant according to claim 1 is characterized in that: It also includes a heat exchanger, which has a tube side inlet, a tube side outlet, a shell side inlet and a shell side outlet. The tube side inlet is connected to the exhaust port of the first dust collector to recover water discharged from the tube side outlet. Condensate is introduced into the shell side inlet. The shell side outlet is connected to the shell side inlet through a circulation pipeline. The circulation pipeline is connected to a first low-pressure heater to pass the heated condensate into the first low-pressure heater for use.

7. The device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant according to claim 6 is characterized in that: It also includes a steam turbine, the steam turbine having an air inlet and an air outlet, steam from a coal-fired power plant is introduced into the steam turbine through the air inlet of the steam turbine, the air outlet of the steam turbine is connected to the air inlet of the heating coil through an air inlet pipe, and the air outlet of the heating coil is connected to the deaerator through an air outlet pipe; The circulation pipeline is connected with a branch pipe and connected to a deaerator through the branch pipe to deoxygenate the condensed water after heat exchange, and the branch pipe is connected to a second low-pressure heater to pass the heated condensed water into the second low-pressure heater for utilization; The air inlet pipe is connected with a bypass, and the bypass is connected to the air inlet of the first air chamber.

8. The device for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant according to claim 6 is characterized in that: A coal cooler is connected between the second wind chamber and the coal mill to cool the lump lignite.

9. A method for preparing briquette fuel from lignite by coupling dual heat sources of a coal-fired power plant, characterized in that: Using the device according to any one of claims 1 to 8, comprising the following steps: The lignite in the raw coal bin is crushed by the raw coal crusher and then enters the predryer. The steam of the coal-fired power plant is passed through the steam turbine into the heating coil in the predryer to predry the crushed lignite. The first fan is started to evenly distribute the heat in the predryer. The dried coal powder and gas-water enter the first dust collector for separation. Part of the separated coal powder is passed into the coal-fired boiler for combustion, and the rest of the coal powder is passed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal. Part of the separated gas-water is passed into the heat exchanger to utilize the heat of the gas-water, and the rest of the gas-water is sent to the predryer through the first fan for gas-water circulation; The pre-dried lump lignite enters the fluidized bed upgrading reactor, and the high-temperature flue gas of 300-500°C is extracted from the tail flue of the coal-fired boiler, and after being pressurized by the second fan, it is sent into the fluidized bed upgrading reactor through the second wind chamber, and the lump lignite is further heated and dried. The dried coal powder and gas and water enter the second dust collector for separation, and part of the separated coal powder is passed into the coal-fired boiler for combustion, and the rest of the coal powder is passed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal, and the separated gas and water are passed into the coal-fired boiler for combustion; The lump lignite that has not yet been dried into coal powder in the fluidized bed upgrading reactor is cooled and then fed into a coal mill to be ground into coal powder. A portion of the coal powder is fed into a coal-fired boiler for combustion, and the rest of the coal powder is fed into the finished coal preparation device to be mixed with the raw materials to prepare finished coal.

10. The method according to claim 9, characterized in that The raw materials include any one of asphalt and tar, any one of water and organic wastewater, and an emulsifier. The mass ratio of any one of asphalt and tar, any one of water or organic wastewater, emulsifier and coal powder is 0.5-2.5:0.2-2:0.004-0.02:10.

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