A blast furnace coal injection pulverizing system without drying furnace and its working method

Abstract

The present invention discloses a blast furnace coal-injection pulverizing system and a working method without a drying furnace, including a coal powder bin, a vibrating screen, a feeder, a bin top dust collector, a bag collector, a raw coal bin, a coal feeder, a medium-speed coal mill, a hot air induced draft fan 1, a hot air induced draft fan 2, a chimney and a hot blast furnace system. The blast furnace coal-injection pulverizing system without a drying furnace of the present invention eliminates the most flammable media, blast furnace gas and coke oven gas, in the coal-injection area by removing the drying furnace, thereby improving the safety factor in the area. At the same time, the entire process flow is simplified and more efficient by eliminating the operation of the drying furnace. By using all the waste gas of the hot blast furnace as the drying gas, the unfavorable factor of ultra-high temperature gas entering the pulverizing system when the drying furnace is abnormally controlled is avoided. Removing the drying furnace also saves part of the investment cost of the drying furnace for the design of the coal-injection system.

Description

Technical Field

[0001] The invention belongs to the field of coal injection pulverizing, and in particular relates to a blast furnace coal injection pulverizing system without a drying furnace. The invention also relates to a working method of the blast furnace coal injection pulverizing system without a drying furnace. Background Art

[0002] Pulverized coal injection in blast furnaces is an important energy-saving technology for changing the fuel structure of blast furnaces and replacing coke with coal in the blast furnace ironmaking process. It plays an important role in reducing the cost per ton of iron, alleviating the shortage of coking coal resources and reducing environmental pollution, and has significant economic, environmental and social benefits.

[0003] At present, the design of domestic blast furnace coal injection system adopts drying furnace system, which is mixed with the waste gas after heat exchange with the hot blast furnace of the blast furnace as the drying high-temperature waste gas source of the pulverizing system. The high-temperature waste gas of the drying furnace is used to adjust the temperature of the entire waste gas. The mixed waste gas is used as the drying and conveying carrier of the raw coal of the pulverizing system, and is sent to the bag box for gas-powder separation. The clean gas after separation is discharged into the atmosphere through the main exhaust fan.

[0004] At present, coal injection system is used in blast furnace ironmaking to reduce fuel cost. The coal injection system uses flue gas for drying and carrier in the process of grinding raw coal into powder, which is the current common process. The flue gas used for powder making comes from two aspects. One is the waste gas generated by the hot blast furnace of the blast furnace, and the other is the mixed waste gas formed by the high-temperature flue gas generated by the combustion of blast furnace gas in the self-built drying furnace for powder making. In the coal injection area, due to the presence of combustible coal powder, blast furnace gas, and coke oven gas, there are multiple dangers in the entire area at the same time. The leakage of coal powder and coal gas in the production process will become a serious unsafe factor, affecting the production safety of the entire area. Therefore, the coal injection area is also designated as a first-level fire prevention area. Summary of the invention

[0005] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide a blast furnace coal injection pulverizing system without a drying furnace, which solves the problem that the current blast furnace coal injection pulverizing system uses a drying furnace, and there are flammable coal powder, blast furnace gas, and coke oven gas, which are not conducive to the safe production of the entire area. The leakage of coal powder and gas in the production process will become a serious unsafe factor, affecting the production safety of the entire area, and not utilizing the production and manufacturing of the enterprise. The present invention also provides a working method of a blast furnace coal injection pulverizing system without a drying furnace. The working principle is simple and easy to implement, which reduces the potential hazards in the production process of the enterprise, improves safety, and is suitable for large-scale industrial applications.

[0006] Technical solution: A blast furnace coal injection pulverizing system without a drying furnace, comprising a pulverized coal bin, a vibrating screen, a feeder, a bin top dust collector, a bag collector, a raw coal bin, a coal feeder, a medium-speed coal mill, a hot air induced draft fan 1, a chimney and a hot blast furnace system, wherein one branch of the hot blast furnace system is connected to the chimney through a valve and a pipe, and another branch of the hot blast furnace system is connected to the medium-speed coal mill through a hot air induced draft fan 1, a valve and a pipe, the raw coal bin is connected to the feed port of the medium-speed coal mill through the coal feeder, the discharge port of the medium-speed coal mill is connected to the bag collector, the bag collector is connected to the feeder, the feeder is connected to the pulverized coal bin through the vibrating screen, and the bin top dust collector is arranged on the pulverized coal bin. The blast furnace coal injection pulverizing system without the drying furnace of the present invention eliminates the most flammable media, blast furnace gas and coke oven gas, in the coal injection area by removing the drying furnace, thereby improving the safety factor in the area. At the same time, the entire process flow is simplified and more efficient by eliminating the operation of the drying furnace. By using all the waste gas of the hot blast furnace as the drying gas, the unfavorable factor of ultra-high temperature gas entering the pulverizing system when the drying furnace is abnormally controlled is avoided. The elimination of the drying furnace also saves part of the investment cost of the drying furnace for the design of the coal injection system.

[0007] Furthermore, the above-mentioned blast furnace coal injection pulverizing system without the drying furnace, the hot blast furnace system is composed of a group of hot blast furnaces, and the hot blast furnace is provided with an air regulating valve, a hot blast valve, an air combustion valve, a flue valve 1, a pressurizing valve, a cold air valve 1, an exhaust gas valve, a flue valve, a gas regulating valve and a gas purge valve, the gas regulating valve is connected to the same gas pipeline, the air regulating valve is connected to the same air pipeline, the hot blast valve is connected to the same hot air pipeline, and the hot air pipeline connected to the hot blast valve is connected to the blast furnace, and the cold air valve 1 is connected to the same cold air pipeline.

[0008] Furthermore, in the above-mentioned blast furnace coal injection pulverizing system without the drying furnace, a flue gas bypass valve and a flue gas heat exchanger are provided between the hot blast furnace system and the chimney.

[0009] Furthermore, in the above-mentioned blast furnace coal injection pulverizing system without the drying furnace, a high-temperature exhaust gas regulating valve, a hot air exhaust gas shut-off valve and a hot air exhaust gas regulating valve are provided between the hot blast furnace system and the hot air induced draft fan.

[0010] Furthermore, in the above-mentioned blast furnace coal injection pulverizing system without the drying furnace, a flue valve 2, an exhaust gas recirculation valve and a cold air valve 2 are provided between the hot air induced draft fan 1 and the medium speed coal mill.

[0011] Furthermore, in the above-mentioned blast furnace coal injection pulverizing system without the drying furnace, the medium-speed coal mill is connected to a coal mill lubricating oil pump, a coal mill sealing fan and a coal mill motor, and the coal mill lubricating oil pump is connected to a coal mill lubricating oil station.

[0012] Furthermore, in the above-mentioned blast furnace coal injection pulverizing system without the drying furnace, the bag collector is provided with a main exhaust fan.

[0013] Furthermore, in the above-mentioned blast furnace coal injection pulverizing system without the drying furnace, a coal feeder inlet valve is provided between the raw coal bin and the coal feeder.

[0014] The present invention provides a working method of a blast furnace coal injection pulverizing system without a drying furnace, comprising the following steps:

[0015] 1) Start the vibrating screen, feeder and bag collector;

[0016] 2) Start the coal mill lubricating oil pump and coal mill sealing fan, and open the flue valve 2;

[0017] 3) Start the main exhaust fan, and the entire milling system generates negative pressure;

[0018] 4) A group of hot air furnaces are started, gas passes through the gas regulating valve, air passes through the air regulating valve, and cold air passes through the cold air valve 1 and rushes into the hot air furnace respectively;

[0019] 5) The hot blast furnace works and the hot blast generated by the hot blast furnace is sent into the blast furnace;

[0020] 6) The waste gas generated by the hot blast furnace is sent into the medium-speed coal mill through the waste gas valve under the action of the hot blast induced draft fan 1;

[0021] 7) When the temperature at the bag collector outlet reaches 60°C, start the medium-speed coal mill, open the coal feeder inlet valve, and feed 25% of the designed amount of coal into the coal feeder;

[0022] 8) Open the high-temperature exhaust gas regulating valve and adjust the inlet temperature of the medium-speed coal mill to the specified value of 260°C;

[0023] 9) The pulverized coal from the medium-speed coal mill enters the bag collector under the action of the main exhaust fan. The pulsating vibration of the bag collector shakes the pulsating coal into the ash bin, and then reaches the vibrating screen through the feeder. After the impurities are screened out, it enters the pulsated coal bin.

[0024] It can be seen from the above technical scheme that the present invention has the following beneficial effects: the blast furnace coal injection pulverizing system removing the drying furnace of the present invention removes the dangerous sources, blast furnace gas and coke oven gas in the entire coal injection area by removing the drying furnace system. The investment cost of the entire drying furnace is saved from the design scheme of the system, and the use of the system's constant open flame coke oven gas is saved. The blast furnace gas burned in the original system is no longer used, and is used for hot blast furnace burning instead.

[0025] Since the entire drying furnace system is removed, the investment cost of the entire coal injection system will be greatly reduced in the design plan. The cost of the entire drying furnace system accounts for about 10~12% of the total investment cost.

[0026] The entire powder making system without the drying furnace system will become safer and the operation control will be simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the blast furnace coal injection pulverizing system without the drying furnace according to the present invention;

[0028] Figure 2 The figure is a schematic diagram of the hot blast stove system of the present invention.

[0029] In the figure: coal powder bin 1, vibrating screen 2, feeder 3, silo top dust collector 4, bag collector 5, raw coal bin 6, coal feeder 7, medium speed coal mill 8, hot air induced draft fan 9, chimney 11, hot air furnace system 12, hot air furnace 13, air regulating valve 14, hot air valve 15, air combustion valve 16, flue valve 17, charging valve 18, cold air valve 19, exhaust valve 20, flue valve 21, gas regulation Valve 22, gas purge valve 23, flue gas bypass valve 24, flue gas heat exchanger 25, high-temperature exhaust gas regulating valve 26, hot air exhaust gas cut-off valve 27, hot air exhaust gas regulating valve 28, flue valve 2 29, exhaust gas recirculation valve 30, cold air valve 2 31, coal mill lubricating oil pump 32, coal mill sealing fan 33, coal mill motor 34, coal mill lubricating oil station 35, main exhaust fan 36, coal feeder inlet valve 37. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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.

[0032] 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, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise clearly specified.

[0033] 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 connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication 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.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0035] Example

[0036] like Figure 1 , 2The blast furnace coal injection pulverizing system for removing the drying furnace comprises a pulverized coal bin 1, a vibrating screen 2, a feeder 3, a bin top dust collector 4, a bag collector 5, a raw coal bin 6, a coal feeder 7, a medium-speed coal mill 8, a hot air induced draft fan 9, a chimney 11 and a hot blast furnace system 12, wherein one branch of the hot blast furnace system 12 is connected to the chimney 11 through a valve and a pipeline, and another branch of the hot blast furnace system 12 is connected to the medium-speed coal mill 8 through a hot air induced draft fan 9, a valve and a pipeline, the raw coal bin 6 is connected to the feeding port of the medium-speed coal mill 8 through the coal feeder 7, the discharging port of the medium-speed coal mill 8 is connected to the bag collector 5, the bag collector 5 is connected to the feeder 3, the feeder 3 is connected to the pulverized coal bin 1 through the vibrating screen 2, and the bin top dust collector 4 is arranged on the pulverized coal bin 1. The hot blast furnace system 12 is composed of a group of hot blast furnaces 13, on which are arranged air regulating valves 14, hot blast valves 15, air combustion valves 16, flue valves 17, charging valves 18, cold blast valves 19, waste gas valves 20, flue valves 21, gas regulating valves 22 and gas purge valves 23. The gas regulating valves 22 are connected to the same gas pipeline, the air regulating valves 14 are connected to the same air pipeline, the hot blast valves 15 are connected to the same hot blast pipeline, and the hot blast pipeline connected to the hot blast valves 15 is connected to the blast furnace, and the cold blast valves 19 are connected to the same cold blast pipeline. A flue gas bypass valve 24 and a flue gas heat exchanger 25 are arranged between the hot blast furnace system 12 and the chimney 11. A high-temperature waste gas regulating valve 26, a hot blast waste gas cut-off valve 27 and a hot blast waste gas regulating valve 28 are arranged between the hot blast furnace system 12 and the hot blast induced draft fan 9. After entering the coal mill, the hot air exhaust gas plays two roles. One is to bring in the corresponding heat to dry the raw coal; the other is to serve as the conveying medium of the coal mill system to convey the ground coal powder to the bag box for gas-powder separation. The qualified exhaust gas after separation is discharged into the atmosphere through the chimney after passing through the main exhaust fan. The finished coal powder after separation is shaken off into the ash bin by the pulsating vibration of the bag, and then reaches the vibrating screen through the feeder and enters the coal powder bin after screening out the impurities, and is stored for blast furnace injection. Flue valve 29, tail gas recirculation valve 30 and cold air valve 2 31 are arranged between the hot air induced draft fan 1 9 and the medium-speed coal mill 8. The medium-speed coal mill 8 is connected to a coal mill lubricating oil pump 32, a coal mill sealing fan 33 and a coal mill motor 34, and the coal mill lubricating oil pump 32 is connected to a coal mill lubricating oil station 35. The bag collector 5 is provided with a main exhaust fan 36. The pulverizing system starts the main exhaust fan 36, and the whole pulverizing system generates negative pressure. The exhaust induced draft fan introduces the waste flue gas after heat exchange from the hot air furnace into the mixing chamber of the drying furnace, and mixes it with the high-temperature flue gas generated by the drying furnace itself, reaches the set temperature, and enters the coal mill to dry the raw coal. A coal feeder inlet valve 37 is provided between the raw coal bin 6 and the coal feeder 7.

[0037] Based on the above structure, the present invention provides a working method of a blast furnace coal injection pulverizing system removing a drying furnace, comprising the following steps:

[0038] 1) Start the vibrating screen 2, feeder 3 and bag collector 5;

[0039] 2) Start the coal mill lubricating oil pump 32 and the coal mill sealing fan 33, and open the flue valve 2 29;

[0040] 3) Start the main exhaust fan 36, and the entire milling system generates negative pressure;

[0041] 4) A group of hot blast furnaces 13 are started, gas passes through the gas regulating valve 22, air passes through the air regulating valve 14, and cold air passes through the cold air valve 19 and rushes into the hot blast furnaces 13 respectively;

[0042] 5) The hot blast stove 13 works, and the hot blast generated by the hot blast stove 13 is sent into the blast furnace;

[0043] 6) The waste gas generated by the hot blast furnace 13 is sent into the medium-speed coal mill 8 through the waste gas valve 20 under the action of the hot blast induced draft fan 9;

[0044] 7) When the temperature at the outlet of the bag collector 5 reaches 60°C, start the medium-speed coal mill 8, open the coal feeder inlet valve 37, and feed 25% of the designed amount of coal to the coal feeder 7;

[0045] 8) Open the high-temperature exhaust gas regulating valve 26 and adjust the inlet temperature of the medium-speed coal mill 8 to the specified value of 260°C;

[0046] 9) The pulverized coal from the medium-speed coal mill 8 enters the bag collector 5 under the action of the main exhaust fan 36. The pulsating vibration of the bag collector 5 shakes the pulsating coal into the ash bin, and then reaches the vibrating screen 2 through the feeder 3. After the impurities are screened out, the pulsated coal enters the pulsated coal bin 1.

[0047] The blast furnace coal injection pulverizing system without drying furnace adopted by the present invention:

[0048] 1. The drying furnace part of the blast furnace coal injection system was removed from the design;

[0049] 2. After removing the drying furnace system, the exhaust gas introduced from the hot air furnace exhaust pipe has an average temperature of 165°C and is used as low-temperature exhaust gas;

[0050] 3. Lead out an exhaust gas pipe from the front end of the inlet of the heat exchanger of the exhaust gas pipe of the hot blast furnace as a supplement to the high-temperature exhaust gas of the powder making system. The exhaust gas temperature before heat exchange is uniformly between 320 and 350°C;

[0051] 4. A regulating valve is installed on the exhaust gas pipeline to control the amount of exhaust gas introduced and adjust the temperature of the mixed exhaust gas;

[0052] 5. During normal production, the waste gas usage after heat exchange accounts for 75~80%, and the waste gas usage before heat exchange accounts for 20~25%, which can meet the needs of milling production;

[0053] 6. When the pulverizing system is started, hot exhaust gas is introduced through the system induced draft fan to preheat the entire pulverizing system. When the system bag outlet temperature rises to 60°C, the high-temperature exhaust gas regulating valve is opened to introduce high-temperature exhaust gas to increase the pulverizer inlet temperature for normal coal pulverizing production.

[0054] 7. Since the pulverizing system uses part of the waste gas that has not been heat exchanged, the amount of gas for heat exchange decreases, and the waste gas from the hot blast furnace is adjusted synchronously to maintain a high temperature, so that the increased furnace gas and the gas removed by the pulverizing system are balanced as a whole.

[0055] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A blast furnace coal injection pulverizing system without a drying furnace, characterized in that: The invention comprises a pulverized coal bin (1), a vibrating screen (2), a feeder (3), a bin top dust collector (4), a bag collector (5), a raw coal bin (6), a coal feeder (7), a medium-speed coal mill (8), a hot air induced draft fan (9), a chimney (11) and a hot air furnace system (12), wherein one branch of the hot air furnace system (12) is connected to the chimney (11) via a valve and a pipe, and another branch of the hot air furnace system (12) is connected to the medium-speed coal mill (8) via a hot air induced draft fan (9), a valve and a pipe, the raw coal bin (6) is connected to the feed port of the medium-speed coal mill (8) via the coal feeder (7), the discharge port of the medium-speed coal mill (8) is connected to the bag collector (5), the bag collector (5) is connected to the feeder (3), and the feeder (3) is connected to the feeder (3) via the vibrating screen ( 2) connected to the pulverized coal bin (1), the bin top dust collector (4) being arranged on the pulverized coal bin (1); the hot blast furnace system (12) being composed of a group of hot blast furnaces (13), the hot blast furnace (13) being provided with an air regulating valve (14), a hot blast valve (15), an air combustion valve (16), a flue valve 1 (17), a charging valve (18), a cold blast valve 1 (19), an exhaust valve (20), a flue valve (21), a gas regulating valve (22) and a gas purge valve (23), the gas regulating valve (22) being connected to the same gas pipeline, the air regulating valve (14) being connected to the same air pipeline, the hot blast valve (15) being connected to the same hot blast pipeline, and the hot blast pipeline connected to the hot blast valve (15) being connected to the blast furnace, and the cold blast valve 1 (19) being connected to the same cold blast pipeline; A high-temperature exhaust gas regulating valve (26), a hot air exhaust gas shut-off valve (27) and a hot air exhaust gas regulating valve (28) are provided between the hot air furnace system (12) and the hot air induced draft fan 1 (9); A flue valve 2 (29), an exhaust gas recirculation valve (30) and a cold air valve 2 (31) are provided between the hot air induced draft fan 1 (9) and the medium speed coal mill (8); The medium-speed coal mill (8) is connected to a coal mill lubricating oil pump (32), a coal mill sealing fan (33) and a coal mill motor (34); the coal mill lubricating oil pump (32) is connected to a coal mill lubricating oil station (35); The bag collector (5) is provided with a main exhaust fan (36); A coal feeder inlet valve (37) is provided between the raw coal bin (6) and the coal feeder (7).

2. The blast furnace coal injection pulverizing system without a drying furnace according to claim 1, characterized in that: A flue gas bypass valve (24) and a flue gas heat exchanger (25) are provided between the hot blast furnace system (12) and the chimney (11).

3. A working method of a blast furnace coal injection pulverizing system removing a drying furnace, using a blast furnace coal injection pulverizing system removing a drying furnace according to any one of claims 1-2, characterized in that: The following steps are involved: 1) Start the vibrating screen (2), feeder (3) and bag collector (5); 2) Start the coal mill lubricating oil pump (32) and the coal mill sealing fan (33), and open the flue valve 2 (29); 3) Start the main exhaust fan (36), so that the entire milling system generates negative pressure; 4) A group of hot blast furnaces (13) are started, and gas passes through the gas regulating valve (22), air passes through the air regulating valve (14), and cold air passes through the cold air valve 1 (19) and rushes into the hot blast furnaces (13) respectively; 5) The hot blast furnace (13) is in operation, and the hot blast generated by the hot blast furnace (13) is fed into the blast furnace; 6) The waste gas generated by the hot blast furnace (13) is sent into the medium-speed coal mill (8) through the waste gas valve (20) under the action of the hot blast induced draft fan (9); 7) When the temperature at the outlet of the bag collector (5) reaches 60°C, start the medium-speed coal mill (8), open the coal feeder inlet valve (37), and feed 25% of the designed amount of coal into the coal feeder (7); 8) Open the high-temperature exhaust gas regulating valve (26) and adjust the inlet temperature of the medium-speed coal mill (8) to the specified value of 260°C; 9) The pulverized coal from the medium-speed coal mill (8) enters the bag collector (5) under the action of the main exhaust fan (36). The pulsating vibration of the bags of the bag collector (5) causes the pulsating coal to fall into the ash bin, and then reaches the vibrating screen (2) through the feeder (3). After the impurities are screened out, the pulsated coal enters the pulsated coal bin (1).

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