Nitrogen protection device of coal milling system

Abstract

The utility model relates to the technical field of coal mill pulverized coal preparation, and discloses a nitrogen protection device for a coal mill system, which comprises the coal mill system and a negative-pressure nitrogen production system, and an air compressor, a suction dryer, a nitrogen production machine, a gas storage tank and a nitrogen distribution cylinder are sequentially arranged on a pipeline in the negative-pressure nitrogen production system. A spiral conveyor, a bag collector, a coal mill, a coal feeder, a middle bin and a finished product pulverized coal bin are arranged in the coal milling system, and an emptying valve is arranged on the gas storage tank. When the pressure in the negative-pressure nitrogen making system is lower than the set value of the nitrogen making machine, the nitrogen making machine is automatically started and is stopped until the pressure of the gas storage tank reaches the set value, the controller gives out a signal after the purity of nitrogen generated by the nitrogen making machine reaches the set value, so that the electromagnetic valve is opened to convey gas outwards, and when the purity does not reach the set value, the nitrogen making machine is stopped. The controller sends out a signal to open the waste gas discharge outlet, gas exceeding the standard is discharged, and the hidden danger of explosion is efficiently eliminated by controlling the coal mill system to be in an inert environment.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mill coal powder preparation, in particular to a nitrogen protection device for a coal mill system. Background Art

[0002] The negative pressure pulverizing system is composed of a coal feeder, a coal mill, a bag dust collector and a coal powder pipeline. The raw coal is ground into finished coal powder, and the coal powder is blown into the furnace of the hot blast furnace for combustion using Roots wind.

[0003] In recent years, due to the grinding of high-volatile lignite, coal mills and bag dust collectors are prone to explosions or deflagrations during operation and storage, which brings great insecurity to the pulverizing system. If it is not discovered and controlled in time, it is very easy to cause coal powder to spontaneously combust, seriously leading to explosion accidents.

[0004] In order to prevent coal mill explosion accidents, flue gas is extracted from the economizer outlet or the induced draft fan outlet and sent to the pulverizing system, and the carbon dioxide in the flue gas is used for explosion prevention. However, the above operation method cannot achieve deep explosion prevention and the operation process is not simple.

[0005] Therefore, we propose a nitrogen protection device for coal mill system. Utility Model Content

[0006] The utility model mainly solves the above technical problems and provides a nitrogen protection device for a coal mill system.

[0007] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a nitrogen protection device for a coal mill system, comprising a coal mill system and a negative pressure nitrogen pressure system, wherein an air compressor, a desiccant, a nitrogen generator, a gas storage tank, and a nitrogen gas cylinder are sequentially arranged on the pipeline in the negative pressure nitrogen pressure system, and a screw conveyor, a bag dust collector, a coal mill, a coal feeder, an intermediate bin, and a finished coal powder bin are arranged in the coal mill system;

[0008] The gas storage tank is provided with an exhaust valve, the nitrogen prepared by the nitrogen generator is stored inside the gas storage tank, the gas storage tank is connected to the nitrogen gas cylinder through a pipeline, and a self-operated regulating valve is provided on the connecting pipeline between the gas storage tank and the nitrogen gas cylinder;

[0009] The nitrogen gas distribution cylinder is connected to the intermediate bin, the coal feeder, the coal mill, the bag dust collector and the screw conveyor respectively through the gas delivery branch pipe.

[0010] Preferably, a filter is provided between the air compressor and the dryer, a check valve is provided on the connecting pipeline between the filter and the dryer, and a check valve is also provided on the connecting pipeline between the dryer and the nitrogen generator. The check valve can prevent airflow backflow.

[0011] Preferably, each of the plurality of groups of air supply branch pipes is provided with an electromagnetic valve.

[0012] Preferably, temperature sensors are provided at the inlet and outlet of the coal mill and the bag-type dust collector, and the temperature of the coal mill system during operation is monitored in real time by the temperature sensors.

[0013] Preferably, the air compressor is provided with a pressure detection switch.

[0014] Preferably, the coal grinding system is also provided with a gas analyzer for monitoring the concentration of carbon monoxide and oxygen produced during the coal grinding process.

[0015] Beneficial Effects

[0016] The utility model provides a nitrogen protection device for a coal mill system, which has the following beneficial effects:

[0017] The nitrogen protection device for coal mill system monitors the concentration of carbon monoxide and oxygen in the production process of coal mill system in real time through gas analyzer, and alarms when the combustible gas value in the system is high. The operator can open the solenoid valve above the nitrogen distribution cylinder in time to accurately degas each point inside the system, and fill the abnormal part with nitrogen to form an inert atmosphere inside the system. The nitrogen making process of the coal mill system is set to automatic control, and the start and stop pressure of the nitrogen making system is manually set. According to the pressure change of the gas storage tank, the outlet flow is manually adjusted by the flow valve to ensure the pressure of the gas storage tank. When the pressure in the negative pressure nitrogen making system is lower than the set value of the nitrogen making machine, the nitrogen making machine will automatically start loading until the pressure of the gas storage tank reaches the set value and then stops. After the purity of the nitrogen generated by the nitrogen making machine reaches the set value, the controller gives a signal to open the solenoid valve to transmit gas to the outside. When the purity does not reach the set value, the controller gives a signal to open the exhaust gas discharge port to discharge the excessive gas to ensure the nitrogen concentration. By controlling the coal mill system to be in an inert environment, the explosion hazard is effectively eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the implementation or the prior art description. Obviously, the drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0019] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0020] Figure 1 This is the overall structural plan of the utility model;

[0021] Figure 2 This is the structural plan of the coal mill system of the utility model;

[0022] Figure 3 This is a structural plan view of the negative pressure nitrogen injection system of the utility model.

[0023] Legend:

[0024] 1. Coal feeder; 2. Coal mill; 3. Intermediate bin; 4. Nitrogen distribution cylinder; 5. Bag dust collector; 6. Gas analyzer; 7. Screw conveyor; 8. Finished coal powder bin; 9. Air compressor; 10. Filter; 11. Dryer; 12. Check valve; 13. Nitrogen generator; 14. Gas storage tank; 15. Self-operated regulating valve; 16. Drain valve. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] Embodiment: A nitrogen protection device for a coal mill system, such as Figure 1-Figure 3 As shown, it includes a coal mill system and a negative pressure nitrogen pressure system, wherein an air compressor 9, a desiccant 11, a nitrogen generator 13, a gas storage tank 14, and a nitrogen gas cylinder 4 are sequentially arranged on the pipeline in the negative pressure nitrogen pressure system, a screw conveyor 7, a bag dust collector 5, a coal mill 2, a coal feeder 1, an intermediate bin 3, and a finished coal powder bin 8 are arranged in the coal mill system, a filter 10 is arranged between the air compressor 9 and the desiccant 11, a check valve 12 is arranged on the connecting pipeline between the filter 10 and the desiccant 11, and a check valve 12 is also arranged on the connecting pipeline between the desiccant 11 and the nitrogen generator 13, and the check valve 12 can prevent the airflow from flowing back;

[0027] The gas storage tank 14 is provided with an exhaust valve 16, and the nitrogen produced by the nitrogen generator 13 is stored inside the gas storage tank 14. The gas storage tank 14 is connected to the nitrogen gas cylinder 4 through a pipeline, and a self-operated regulating valve 15 is provided on the connecting pipeline between the gas storage tank 14 and the nitrogen gas cylinder 4;

[0028] The nitrogen gas cylinder 4 is a cylindrical storage tank for temporary storage of nitrogen. The nitrogen gas cylinder 4 is connected to the intermediate bin 3, the coal feeder 1, the coal mill 2, the bag dust collector 5 and the screw conveyor 7 through the air delivery branch pipe. The multiple groups of air delivery branch pipes are provided with solenoid valves, which can be controlled by remote central control and on-site control. Through such a setting, the nitrogen flow rate can be quantitatively adjusted with high adjustment accuracy, which is conducive to the regulation between various equipments and improves the efficiency of safety work;

[0029] The air compressor 9 is provided with a pressure detection switch, which will automatically load when the pressure is lower than the set value;

[0030] The inlet and outlet of the coal mill 2 and the bag filter 5 are both provided with temperature sensors, and the temperature of the coal mill system during operation is monitored in real time through the provided temperature sensors;

[0031] The coal mill system is also provided with a gas analyzer 6, which monitors the carbon monoxide and oxygen concentrations in the production process of the coal mill system in real time. When the combustible gas value in the system is detected to be high, an alarm is sounded, and the operator can promptly open the solenoid valve above the nitrogen gas cylinder 4 to accurately degrade each point inside the system, and fill nitrogen into the abnormal part to form an inert atmosphere inside the system. The nitrogen making process of the coal mill system is set to automatic control, and the start and stop pressure of the nitrogen making system is manually set. According to the pressure change of the gas storage tank 14, the outlet flow is manually adjusted through the flow valve to ensure the pressure of the gas storage tank 14;

[0032] When the pressure in the negative pressure nitrogen making system is lower than the set value of the nitrogen generator 13, the nitrogen generator 13 will automatically start loading until the pressure of the gas storage tank 14 reaches the set value and then stops. After the purity of the nitrogen generated by the nitrogen generator 13 reaches the set value, the controller gives a signal to open the solenoid valve to transmit gas to the outside. When the purity does not reach the set value, the controller gives a signal to open the exhaust gas discharge port to discharge the excess gas to ensure the nitrogen concentration.

[0033] The working principle of this utility model:

[0034] The gas analyzer 6 is used to monitor the carbon monoxide and oxygen concentrations in the production process of the coal mill system in real time. When the combustible gas value in the system is detected to be high, an alarm is triggered. The operator can promptly open the solenoid valve above the nitrogen distribution cylinder 4 to accurately degas each point inside the system, and fill the abnormal part with nitrogen to form an inert atmosphere inside the system. The nitrogen making process of the coal mill system is set to automatic control, and the start and stop pressure of the nitrogen making system is manually set. According to the pressure change of the gas storage tank 14, the outlet flow is manually adjusted by the flow valve to ensure the pressure of the gas storage tank 14. When the pressure in the negative pressure nitrogen making system is lower than the set value of the nitrogen making machine 13, the nitrogen making machine 13 will automatically start loading until the pressure of the gas storage tank 14 reaches the set value and then stops. After the purity of the nitrogen generated by the nitrogen making machine 13 reaches the set value, the controller gives a signal to open the solenoid valve to transmit gas to the outside. When the purity does not reach the set value, the controller gives a signal to open the exhaust gas discharge port to discharge the excessive gas to ensure the nitrogen concentration.

[0035] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A nitrogen protection device for a coal mill system, comprising a coal mill system and a negative pressure nitrogen system, characterized in that: An air compressor (9), a desiccant (11), a nitrogen generator (13), a gas storage tank (14), and a nitrogen gas distribution cylinder (4) are sequentially arranged on the pipeline in the negative pressure nitrogen generation system; and a screw conveyor (7), a bag dust collector (5), a coal mill (2), a coal feeder (1), an intermediate bin (3), and a finished coal powder bin (8) are arranged in the coal mill system; The gas storage tank (14) is provided with an exhaust valve (16), the nitrogen produced by the nitrogen generator (13) is stored inside the gas storage tank (14), the gas storage tank (14) and the nitrogen gas cylinder (4) are connected via a pipeline, and a self-operated regulating valve (15) is provided on the connecting pipeline between the gas storage tank (14) and the nitrogen gas cylinder (4); The nitrogen gas distribution cylinder (4) is respectively connected to the intermediate bin (3), the coal feeder (1), the coal mill (2), the bag dust collector (5) and the screw conveyor (7) through gas delivery branches.

2. A nitrogen protection device for a coal mill system according to claim 1, characterized in that: A filter (10) is provided between the air compressor (9) and the desiccant (11), a check valve (12) is provided on the connecting pipeline between the filter (10) and the desiccant (11), and a check valve (12) is also provided on the connecting pipeline between the desiccant (11) and the nitrogen generator (13). The check valve (12) can prevent airflow from flowing backwards.

3. A nitrogen protection device for a coal mill system according to claim 1, characterized in that: A plurality of groups of gas supply branch pipes are each provided with an electromagnetic valve.

4. A nitrogen protection device for a coal mill system according to claim 1, characterized in that: Temperature sensors are provided at the inlet and outlet of the coal mill (2) and the bag dust collector (5).

5. A nitrogen protection device for a coal mill system according to claim 1, characterized in that: The air compressor (9) is provided with a pressure detection switch.

6. A nitrogen protection device for a coal mill system according to claim 1, characterized in that: The coal grinding system is also provided with a gas analyzer (6) for monitoring the concentration of carbon monoxide and oxygen generated during the coal grinding process.

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