A circulating fluidized bed apparatus with by-product char and a method of operating the same

Abstract

The application provides a circulating fluidized bed device with by-product coke powder and a running method thereof, and the circulating fluidized bed device comprises a circulating fluidized bed boiler, a separation unit, a cooling unit and a waste heat recovery unit; the circulating fluidized bed boiler comprises a main combustion chamber, a pyrolysis chamber, a secondary combustion chamber and a burnout chamber which are sequentially arranged from bottom to top; the main combustion chamber and the pyrolysis chamber are respectively independently provided with a raw material inlet; the burnout chamber is connected with the separation unit; the pyrolysis chamber is connected with the cooling unit; the separation unit, the waste heat recovery unit and the cooling unit are sequentially connected in a circulation mode; the running method is based on the improvement of the device structure, high-temperature flue gas generated by combustion of the main combustion chamber is directly used for fluidized pyrolysis of raw coal in the pyrolysis chamber, the use requirement is met, high-value coke powder is by-produced, in addition, the separation unit, the cooling unit and the waste heat recovery unit are used in cooperation to achieve the purpose of energy saving and consumption reduction, and good economic benefits are obtained.

Description

Technical Field

[0001] This invention belongs to the field of coal chemical pyrolysis technology, specifically relating to a circulating fluidized bed device for producing by-product coke powder and its operation method. Background Technology

[0002] As the greenhouse effect worsens, new energy power generation has become a key research focus. However, the installed capacity of new energy power generation such as wind power and solar power is still relatively small and cannot meet the large electricity demand in the short term. Therefore, thermal power generation remains the mainstream. Thermal power generation is primarily coal-fired, with coal-fired units accounting for over 80% of the installed capacity. Coal-fired flue gas emissions from coal combustion... x SO2 and Hg pose significant threats to human health and the ecological environment. With the increasing conflict between coal combustion and environmental protection, circulating fluidized bed boilers have become the preferred high-efficiency, low-pollution new combustion technology.

[0003] However, directly feeding ground raw coal into a circulating fluidized bed boiler for combustion is uneconomical. CN105062570A discloses a composite circulating fluidized bed gasification device and method, comprising a pyrolysis chamber, a gasification chamber, and a cyclone separator connected in sequence; the pyrolysis chamber is provided with a raw material inlet, a pyrolysis gas outlet, and a semi-coke outlet, with the pyrolysis gas outlet located above the semi-coke outlet; the gasification chamber is provided with a primary air inlet, a pyrolysis gas inlet, and a semi-coke inlet, with the pyrolysis gas outlet connected to the pyrolysis gas inlet, and the semi-coke outlet connected to the semi-coke inlet via an overflow pipe; the cyclone separator is provided with a gas outlet.

[0004] CN104962302A discloses a pyrolysis process and apparatus for high-temperature mixed materials in a circulating fluidized bed boiler combustion chamber. The process includes a circulating fluidized bed boiler combustion chamber and a fluidized bed pyrolysis reactor with a pyrolysis coal ramp pipe interface. A circulating fluidized bed distribution plate is inclinedly arranged at the upper end of the air chamber within the circulating fluidized bed boiler combustion chamber. A high-temperature mixed material outlet is provided on the side of the furnace wall in the conical section above the fluidized bed distribution plate. The high-temperature mixed material outlet is connected to the bottom side of the reaction chamber of the fluidized bed pyrolysis reactor via a high-temperature mixed material ramp pipe. The annular pyrolysis semi-coke bin of the fluidized bed pyrolysis reactor is connected to the circulating fluidized bed boiler combustion chamber via a pyrolysis semi-coke ramp pipe.

[0005] CN105754621A discloses a coal pyrolysis reactor-circulating fluidized bed combined system and a method for processing coal using the same. The combined system includes a coal pyrolysis reactor and a circulating fluidized bed, which exist independently and do not interfere with each other. It utilizes the existing circulating fluidized bed conveying system to achieve hot delivery of semi-coke, ensure the combustion of semi-coke, and reduce the cost of coal head removal process.

[0006] The above methods all involve the combined use of a fluidized bed boiler and a pyrolyzer, with the generated semi-coke fed into the fluidized bed boiler. This improves the energy utilization rate of the power generation system to a certain extent, thereby enhancing economic efficiency. However, the combined equipment requires a large area and high investment, and its economic benefits need to be further improved.

[0007] In conclusion, how to provide a method that is highly efficient and energy-saving and can further improve the economics of circulating fluidized bed devices has become an urgent technical problem to be solved. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention aims to provide a circulating fluidized bed device for producing coke powder as a byproduct and its operation method. The circulating fluidized bed device improves the structure of the existing circulating fluidized bed boiler and achieves energy saving while producing high-value coke powder through the cooperation of multiple units, thus showing good application prospects.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a circulating fluidized bed device for producing by-product coke powder, the circulating fluidized bed device comprising a circulating fluidized bed boiler, a separation unit, a cooling unit, and a waste heat recovery unit;

[0011] The circulating fluidized bed boiler includes a main combustion chamber, a pyrolysis chamber, a secondary combustion chamber, and a burnout chamber arranged sequentially from bottom to top; a gas distribution plate is provided between the main combustion chamber and the pyrolysis chamber; the main combustion chamber and the pyrolysis chamber are each independently provided with a raw material inlet;

[0012] The burnout chamber is connected to the separation unit;

[0013] The pyrolysis chamber is connected to the cooling unit;

[0014] The separation unit, the waste heat recovery unit, and the cooling unit are connected in a loop in sequence.

[0015] This invention adds a pyrolysis chamber between the main combustion chamber and the auxiliary combustion chamber inside the circulating fluidized bed boiler. Raw materials are fed into the main combustion chamber and the pyrolysis chamber respectively, so that the circulating fluidized bed boiler can meet the usage requirements while producing high-value coke powder as a by-product. At the same time, in conjunction with the separation unit, cooling unit and waste heat recovery unit, it achieves the purpose of energy saving and consumption reduction, and has good economic benefits.

[0016] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0017] As a preferred embodiment of the present invention, the circulating fluidized bed device further includes a crushing unit, which is independently connected to the main combustion chamber and the pyrolysis chamber.

[0018] As a preferred embodiment of the present invention, the separation unit is also connected to the main combustion chamber.

[0019] As a preferred technical solution of the present invention, the side wall of the combustion chamber is provided with a deoxygenated water inlet.

[0020] As a preferred embodiment of the present invention, a steam outlet is provided at the top of the combustion chamber.

[0021] In a second aspect, the present invention provides a method for operating the circulating fluidized bed apparatus described in the first aspect, the method comprising the following steps:

[0022] Raw coal is fed into the main combustion chamber and pyrolysis chamber of the circulating fluidized bed boiler. The flue gas generated in the main combustion chamber enters the pyrolysis chamber to fluidize and pyrolyze the raw coal. The resulting coke powder enters the cooling unit for fluidized cooling. The flue gas generated in the pyrolysis chamber enters the auxiliary combustion chamber for combustion, and then enters the burnout chamber. The burnout flue gas enters the separation unit, and the separated solids are recycled back to the main combustion chamber. The separated flue gas enters the waste heat recovery unit, and after releasing heat, it enters the cooling unit to fluidize and cool the coke powder, and then returns to the separation unit for recycling.

[0023] In this invention, addressing the uneconomical use of only burning raw coal in fluidized bed boilers, the pyrolysis chamber allows the high-temperature flue gas generated in the main combustion chamber to directly fluidize and pyrolyze the raw coal within the chamber, producing high-value coke powder as a byproduct that can be used in industries such as metallurgy, glass, and ceramics. Simultaneously, the fluidized state facilitates the delivery of the coke powder to the cooling unit. Furthermore, the high-temperature flue gas generated during combustion can be further combusted, separated, and its waste heat recovered before entering the cooling unit to fluidize and cool the coke powder, achieving recycling. The overall process is energy-saving and consumption-reducing, beneficial for industrial production.

[0024] As a preferred technical solution of the present invention, the raw coal is crushed before being fed into the main combustion chamber and pyrolysis chamber.

[0025] Preferably, the particle size of the crushed raw coal is <6mm, such as 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm or 5.8mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] In this invention, the particle size of raw coal has a significant impact on the quality of coke powder. If the particle size range is too wide, it will affect the fluidization state of the coal powder in the boiler, thereby affecting the quality of the finished coke powder.

[0027] As a preferred technical solution of the present invention, the temperature of the main combustion chamber is 850-1050℃, such as 850℃, 900℃, 950℃, 1000℃ or 1050℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the pressure in the main combustion chamber is 3 to 14 kPa, such as 3 kPa, 6 kPa, 8 kPa, 10 kPa, 12 kPa or 14 kPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Preferably, the temperature of the pyrolysis chamber is 630 to 680°C, such as 630°C, 635°C, 640°C, 645°C, 650°C, 655°C, 660°C, 665°C, 670°C, 675°C, or 680°C, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0030] Preferably, the pressure in the pyrolysis chamber is -0.05 kPa to 3 kPa, such as -0.05 kPa, 0 kPa, 0.5 kPa, 1.0 kPa, 1.5 kPa, 2.0 kPa, 2.5 kPa or 3.0 kPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] As a preferred technical solution of the present invention, the mass of raw coal in the main combustion chamber is more than 0.2 times the mass of raw coal in the pyrolysis chamber, for example, 0.2 times, 0.3 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times, 1.0 times, 1.1 times, 1.2 times, 1.3 times, 1.4 times or 2 times, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0032] In this invention, the quality of raw coal in the main combustion chamber can be adjusted according to production needs, but it cannot be too low. Otherwise, the raw coal in the pyrolysis chamber cannot be completely pyrolyzed, resulting in waste and poor overall equipment operation.

[0033] As a preferred embodiment of the present invention, deoxygenated water is also introduced into the combustion chamber to generate steam.

[0034] In this invention, the generated steam can be used to generate electricity or as a driving force for other production equipment within the factory.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The circulating fluidized bed device of this invention adds a pyrolysis chamber between the main combustion chamber and the auxiliary combustion chamber inside the circulating fluidized bed boiler. Raw materials are fed into the main combustion chamber and the pyrolysis chamber respectively. The high-temperature flue gas generated by the combustion in the main combustion chamber directly fluidizes and pyrolyzes the raw coal in the pyrolysis chamber. This allows the circulating fluidized bed boiler to meet the requirements for steam production or power generation while producing high-value coke powder as a byproduct. At the same time, it achieves the purpose of energy saving and consumption reduction by combining with the separation unit, cooling unit and waste heat recovery unit, and has good economic benefits. Attached Figure Description

[0037] Figure 1 This is an operation flow diagram of a circulating fluidized bed device for producing by-product coke powder, provided in Application Example 1 of the present invention.

[0038] Among them, 1-circulating fluidized bed boiler, 11-main combustion chamber, 12-pyrolysis chamber, 13-auxiliary combustion chamber, 14-burnout chamber, 2-separation unit, 3-cooling unit, 4-waste heat recovery unit, 5-crushing unit. Detailed Implementation

[0039] To better illustrate the present invention and facilitate understanding of its technical solutions, the present invention is further described in detail below. However, the following embodiments are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0040] The following are typical but non-limiting embodiments of the present invention:

[0041] Example 1:

[0042] This embodiment provides a circulating fluidized bed device for producing by-product coke powder. The circulating fluidized bed device includes a circulating fluidized bed boiler 1, a separation unit 2, a cooling unit 3, and a waste heat recovery unit 4.

[0043] The circulating fluidized bed boiler 1 includes a main combustion chamber 11, a pyrolysis chamber 12, a secondary combustion chamber 13, and a burnout chamber 14 arranged sequentially from bottom to top; the main combustion chamber 11 and the pyrolysis chamber 12 are each independently provided with a raw material inlet;

[0044] The burnout chamber 14 is connected to the separation unit 2;

[0045] The pyrolysis chamber 12 is connected to the cooling unit 3;

[0046] The separation unit 2, the waste heat recovery unit 4, and the cooling unit 3 are connected in a loop in sequence.

[0047] The circulating fluidized bed device also includes a crushing unit 5, which is independently connected to the main combustion chamber 11 and the pyrolysis chamber 12.

[0048] The separation unit 2 is also connected to the main combustion chamber 11.

[0049] The burnout chamber 14 has a deoxygenated water inlet on its side wall and a steam outlet on its top.

[0050] Example 2:

[0051] This embodiment provides a circulating fluidized bed device for producing by-product coke powder. The circulating fluidized bed device includes a circulating fluidized bed boiler 1, a separation unit 2, a cooling unit 3, and a waste heat recovery unit 4.

[0052] The circulating fluidized bed boiler 1 includes a main combustion chamber 11, a pyrolysis chamber 12, a secondary combustion chamber 13, and a burnout chamber 14 arranged sequentially from bottom to top; the main combustion chamber 11 and the pyrolysis chamber 12 are each independently provided with a raw material inlet;

[0053] The burnout chamber 14 is connected to the separation unit 2;

[0054] The pyrolysis chamber 12 is connected to the cooling unit 3;

[0055] The separation unit 2, the waste heat recovery unit 4, and the cooling unit 3 are connected in a loop in sequence.

[0056] The separation unit 2 is also connected to the main combustion chamber 11.

[0057] The burnout chamber 14 has a deoxygenated water inlet on its side wall and a steam outlet on its top.

[0058] Application Example 1:

[0059] This application example provides an operation method for a circulating fluidized bed device that produces by-product coke powder. The circulating fluidized bed device is the one described in Example 1, and its operation flowchart is as follows: Figure 1 As shown, the operating method includes the following steps:

[0060] The raw coal is crushed to control the particle size to 4-5 mm. 100 tons of crushed raw coal is fed into the main combustion chamber 11 of the circulating fluidized bed boiler 1, and 500 tons of crushed raw coal is fed into the pyrolysis chamber 12. The raw coal in the main combustion chamber 11 is burned at 900℃ and 3-13 kPa. The resulting flue gas enters the pyrolysis chamber 12, where the raw coal undergoes fluidized bed pyrolysis at 650℃ and a pressure of -0.05-3 kPa. The resulting coke powder enters the cooling unit 3 for fluidized bed cooling, yielding 250 tons of coke powder product. The flue gas generated during pyrolysis enters the auxiliary combustion chamber... Combustion occurs in combustion chamber 13 at a temperature of 850℃ and a pressure of -0.05 to 0.05 kPa. The combustible gas then enters combustion chamber 14, where deoxygenated water is introduced. The combustion temperature is 900℃ and the pressure is -0.05 to 0.05 kPa, generating 1354 tons of steam for power generation. The combustible gas then enters separation unit 2, where the separated solids are recycled back to the main combustion chamber 11. The separated gas then enters waste heat recovery unit 4 for heat recovery and utilization. After waste heat recovery, the gas enters cooling unit 3 for fluidized cooling of the coke powder, and then returns to separation unit 2 for recycling.

[0061] Application Example 2:

[0062] This application example provides an operation method for a circulating fluidized bed device that produces by-product coke powder. The circulating fluidized bed device is the circulating fluidized bed device in Example 1. The operation method includes the following steps:

[0063] The raw coal is crushed to control the particle size to 4-5 mm. 200 tons of crushed raw coal are fed into the main combustion chamber 11 of the circulating fluidized bed boiler 1, and then into the pyrolysis chamber 12. The raw coal in the main combustion chamber 11 is burned at 900℃ and 3-13 kPa. The resulting flue gas enters the pyrolysis chamber 12, where the raw coal undergoes fluidized bed pyrolysis at 650℃ and a pressure of -0.05-3 kPa. The resulting coke powder enters the cooling unit 3 for fluidized bed cooling, yielding 100 tons of coke powder product. The flue gas generated during pyrolysis enters the auxiliary combustion chamber... Combustion occurs in combustion chamber 13 at a temperature of 850℃ and a pressure of -0.05 to 0.05 kPa. The combustible gas then enters combustion chamber 14, where deoxygenated water is introduced. The combustion temperature is 900℃ and the pressure is -0.05 to 0.05 kPa, generating 1724 tons of steam for power generation. The combustible gas then enters separation unit 2, where the separated solids are recycled back to the main combustion chamber 11. The separated gas then enters waste heat recovery unit 4 for heat recovery and utilization. After waste heat recovery, the gas enters cooling unit 3 for fluidized cooling of the coke powder, and then returns to separation unit 2 for recycling.

[0064] Application Example 3:

[0065] This application example provides an operation method for a circulating fluidized bed device that produces by-product coke powder. The circulating fluidized bed device is the circulating fluidized bed device in Example 1. The operation method includes the following steps:

[0066] The raw coal is crushed to control the particle size to 4-5 mm. 300 tons of crushed raw coal are fed into the main combustion chamber 11 of the circulating fluidized bed boiler 1, and 200 tons of crushed raw coal are fed into the pyrolysis chamber 12. The raw coal in the main combustion chamber 11 is burned at 900℃ and 3-13 kPa. The resulting flue gas enters the pyrolysis chamber 12, where the raw coal undergoes fluidized bed pyrolysis at 650℃ and a pressure of -0.05-3 kPa. The resulting coke powder enters the cooling unit 3 for fluidized bed cooling, yielding 100 tons of coke powder product. The flue gas generated during pyrolysis enters the auxiliary combustion chamber... Combustion occurs in combustion chamber 13 at a temperature of 850℃ and a pressure of -0.05 to 0.05 kPa. The combustible gas then enters combustion chamber 14, where deoxygenated water is introduced. The combustion temperature is 900℃ and the pressure is -0.05 to 0.05 kPa, generating 2464 tons of steam for power generation. The combustible gas then enters separation unit 2, where the separated solids are recycled back to the main combustion chamber 11. The separated gas then enters waste heat recovery unit 4 for heat recovery and utilization. After waste heat recovery, the gas enters cooling unit 3 for fluidized cooling of the coke powder, and then returns to separation unit 2 for recycling.

[0067] Comparative application example 1:

[0068] This comparative application example provides an operation method for a circulating fluidized bed device that produces coke powder as a byproduct. The circulating fluidized bed device is the same as the circulating fluidized bed device in Example 1. The operation method is the same as the method in the application, except that the particle size of the raw coal after crushing is controlled to be 0-10 mm.

[0069] Under these conditions, an excessively wide particle size range affects the fluidization state of pulverized coal within the boiler, leading to a decline in the quality of the coke powder product.

[0070] The present invention has been illustrated with the above embodiments to explain the detailed method of the present invention. However, the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the operation of the present invention, additions of auxiliary operations, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A circulating fluidized bed device for producing coke powder as a byproduct, characterized in that, The circulating fluidized bed device includes a circulating fluidized bed boiler, a separation unit, a cooling unit, and a waste heat recovery unit; The circulating fluidized bed boiler includes a main combustion chamber, a pyrolysis chamber, a secondary combustion chamber, and a burnout chamber arranged sequentially from bottom to top; a gas distribution plate is provided between the main combustion chamber and the pyrolysis chamber; the main combustion chamber and the pyrolysis chamber are each independently provided with a raw material inlet; The burnout chamber is connected to the separation unit; The side wall of the combustion chamber is provided with a deoxygenated water inlet; the top of the combustion chamber is provided with a steam outlet; The pyrolysis chamber is connected to the cooling unit; The separation unit, the waste heat recovery unit, and the cooling unit are connected in a loop in sequence.

2. The circulating fluidized bed device according to claim 1, characterized in that, The circulating fluidized bed device also includes a crushing unit, which is independently connected to the main combustion chamber and the pyrolysis chamber.

3. The circulating fluidized bed device according to claim 1, characterized in that, The separation unit is also connected to the main combustion chamber.

4. A method for operating a circulating fluidized bed apparatus as described in any one of claims 1-3, characterized in that, The operating method includes the following steps: Raw coal is fed into the main combustion chamber and pyrolysis chamber of the circulating fluidized bed boiler. The flue gas generated in the main combustion chamber enters the pyrolysis chamber to fluidize and pyrolyze the raw coal. The resulting coke powder enters the cooling unit for fluidized cooling. The flue gas generated in the pyrolysis chamber enters the auxiliary combustion chamber for combustion, and then enters the burnout chamber. The burnout flue gas enters the separation unit, and the separated solids are recycled back to the main combustion chamber. The separated flue gas enters the waste heat recovery unit, and after releasing heat, it enters the cooling unit to fluidize and cool the coke powder, and then returns to the separation unit for recycling.

5. The operating method according to claim 4, characterized in that, The raw coal is crushed before being fed into the main combustion chamber and pyrolysis chamber.

6. The operating method according to claim 5, characterized in that, The particle size of the crushed raw coal is <6mm.

7. The operating method according to claim 4, characterized in that, The temperature of the main combustion chamber is 850–1050°C.

8. The operating method according to claim 4, characterized in that, The pressure in the main combustion chamber is 3–14 kPa.

9. The operating method according to claim 4, characterized in that, The temperature of the pyrolysis chamber is 630–680°C.

10. The operating method according to claim 4, characterized in that, The pressure in the pyrolysis chamber is -0.05 to 3 kPa.

11. The operating method according to claim 4, characterized in that, The mass of raw coal in the main combustion chamber is more than 0.2 times the mass of raw coal in the pyrolysis chamber.

12. The operating method according to claim 4, characterized in that, Deoxygenated water is also introduced into the combustion chamber to generate steam.

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