KR102148533B1 - Low rank coal pulverizing system - Google Patents

Abstract

The low-grade coal pulverization system according to an embodiment of the present invention may include a pulverizer for pulverizing and pulverizing low-grade coal, and a microwave irradiation unit for removing moisture by irradiating microwaves into the pulverizer.

Description

Low-grade coal pulverization system {LOW RANK COAL PULVERIZING SYSTEM}

The present application relates to a low-grade coal pulverization system, and in particular, to a low-grade coal pulverization system capable of effectively increasing the pulverization efficiency of low-grade coal and preventing spontaneous ignition that may occur in the pulverizer when pulverizing low-grade coal,

This is derived from a study conducted as part of the commercialization technology development (general) of the Korea Institute of Energy Technology Evaluation and Evaluation of 100MW ultra-supercritical pressure (USC) thermal power generation by the Ministry of Trade, Industry and Energy. [Project management number: 2010101010027C, Project name: Supercritical pressure thermal power generation simulator development (Detail 2)]

As a countermeasure for high oil prices, many studies on the technology of utilizing Low Rank Coal (LRC) are being discussed. Among the coals currently used by industry, brown coal/lignite and sub-bituminous coal are among the low-grade coals, and have abundant reserves and are evenly distributed worldwide, but due to their high moisture content and the possibility of spontaneous combustion. It is a situation that is having difficulty using it.

In particular, since low-grade coal contains a lot of moisture (surface moisture and pore moisture), there is a disadvantage in that the pulverization efficiency is significantly lowered due to the buffering action of moisture during pulverization. Accordingly, a method of removing moisture by injecting a high-temperature gas of 250°C or higher into the pulverizer as a propulsion medium for transporting pulverized coal in the pulverizer is being considered, but in this case, the pulverized coal is devolatilized by thermal contact when pulverizing on a high-temperature gas of 250°C Devolatilized hydrocarbons and vapor gases can act as an ignition source and cause spontaneous ignition.

Therefore, there is a need for a method of preventing spontaneous ignition that may occur within the pulverizer when pulverizing low-grade coal and effectively increasing the pulverization efficiency of low-grade coal.

In the art, there is a need for a low-grade coal pulverization system capable of preventing spontaneous ignition that may occur in the pulverizer when pulverizing low-grade coal and effectively increasing the pulverization efficiency of low-grade coal.

The low-grade coal pulverization system according to an embodiment of the present invention may include a pulverizer for pulverizing and pulverizing low-grade coal, and a microwave irradiation unit for removing moisture by irradiating microwaves into the pulverizer.

In the low-grade coal pulverization system according to an embodiment of the present invention, the pulverizer includes a rotating shaft that generates rotational power through rotation, a power transmission unit that transmits rotational power generated by the rotational shaft, and the power transmission unit. Depending on the transmitted rotational power, a roller for pulverizing and pulverizing low-grade coal by rotating around the rotational power, an atmospheric air and circulation gas supply unit for transferring the pulverized pulverized coal pulverized by the roller by supplying atmospheric air and circulating gas. It may include a guide vane for separating the transferred pulverized coal by particle size by using a centrifugal force, and for passing the ultra-fine coal among the transferred pulverized coal, and an outlet for discharging the ultra-fine coal passing through the guide vane to a cyclone. .

In the low-grade coal pulverization system according to an embodiment of the present invention, at least one of the power transmission unit and the roller may be coated with a Teflon material, and the inside of the pulverizer may be coated with an alumina material.

In the low-grade coal pulverization system according to an embodiment of the present invention, the microwave irradiation unit includes: a magnetron that generates and supplies microwaves for irradiation in the pulverizer, a tuner that performs impedance matching on microwaves supplied by the magnetron, And a microwave irradiator for irradiating microwaves impedance matched by the tuner into the differentiator, a dummy rod for absorbing and removing microwaves reflected from the differentiator, and a circulator for inducing microwaves reflected from the differentiator to the dummy rod You can do it.

In the low-grade coal pulverization system according to an embodiment of the present invention, the microwave irradiation unit includes a power supply device for supplying power to the magnetron, a coupler measuring the intensity of microwaves reflected from the pulverizer, and a measurement result from the coupler Further comprising a temperature control device for controlling the output of the power supply according to, wherein the temperature control device, when the intensity of the microwave reflected from the differentiator is more than a predetermined level, stops the output of the power supply Or it may be characterized by reducing.

In the low-grade coal pulverization system according to an embodiment of the present invention, the microwave irradiation unit includes a power supply device for supplying power to the magnetron, a temperature sensing device for measuring a temperature inside the pulverizer, and measurement from the temperature sensing device Further comprising a temperature control device for controlling the output of the power supply according to the result, wherein the temperature control device, when the internal temperature of the differentiator is higher than a predetermined temperature, to stop or reduce the output of the power supply It can be characterized.

In the low-grade coal pulverization system according to an embodiment of the present invention, the temperature sensing device may be characterized by using a thermocouple shielded with Teflon-coated stainless steel.

In addition, not all the features of the present invention are listed in the means for solving the above-described problems. Various features of the present invention and advantages and effects thereof may be understood in more detail with reference to the following specific embodiments.

When pulverizing low-grade coal, spontaneous ignition that may occur within the pulverizer can be prevented and the pulverization efficiency of low-grade coal can be effectively increased.

1 is a diagram showing the configuration of a low-grade coal pulverization system according to an embodiment of the present invention,
2 is a diagram showing a detailed configuration of a differentiator according to an embodiment of the present invention;
3 is a cross-sectional view of a pulverizer including a plurality of rollers according to an embodiment of the present invention;
4 is a diagram showing a detailed configuration of a microwave irradiation unit according to an embodiment of the present invention, and
5A and 5B are cross-sectional and side views of a microwave irradiation unit including a plurality of microwave irradiators according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided in order to more completely explain the present invention to those with average knowledge in the art. In the drawings, the shapes and sizes of elements may be exaggerated for clearer explanation.

Hereinafter, an embodiment of the present invention proposes a low-grade coal pulverization system capable of preventing spontaneous ignition that may occur in the pulverizer when pulverizing low-grade coal and effectively increasing the pulverization efficiency of low-grade coal.

1 is a diagram showing the configuration of a low-grade coal pulverization system according to an embodiment of the present invention.

As shown, the low-grade coal pulverization system includes a pulverizer 100 and a microwave irradiation unit 110.

Referring to FIG. 1, the pulverizer 100 pulverizes low-grade coal and discharges the pulverized coal into a cyclone (not shown).

The microwave irradiation unit 110 irradiates microwaves into the pulverizer 100 to remove moisture (surface moisture and pore moisture) contained in raw coal and pulverized coal of low-grade coal.

2 is a diagram showing a detailed configuration of a differentiator 100 according to an embodiment of the present invention.

As shown, the pulverizer 100, the rotary shaft 202, one or more power transmission units (204-1, 204-3), one or more rollers (206-1, 206-3), atmospheric air and circulation gas supply unit (208), a guide vane (210), a discharge port (212), a rotary shaft support 214, and includes a roller support (216).

Referring to FIG. 2, the rotation shaft 202 generates rotational power through rotation.

The one or more power transmission units (204-1, 204-3) are connected to the rotation shaft (202), the rollers (206-1, 206-3) connected to the rotational power generated by the rotation shaft (202) To pass on.

The at least one roller (206-1, 206-3) is connected to the at least one power transmission unit (204-1, 204-3), by the power transmission unit (204-1, 204-3) connected According to the transmitted rotational power, the low-grade coal is pulverized and pulverized by rotating around the rotating shaft 202. Here, the low-grade coal is introduced through the coal inlet 218 and pulverized and pulverized by rotation of the rollers 206-1 and 206-3. For example, as shown in FIG. 3, when a plurality of rollers 306-1, 306-2, 306-3, and 306-4 are present in the pulverizer, a plurality of rollers 306-1, 306-2, and 306- 3, 306-4) are each transmitted through a plurality of power transmission units (304-1, 304-2, 304-3, 304-4) connected to the rotational power generated by the rotation shaft 302, and received The low-grade coal can be pulverized and pulverized by rotating around the rotation shaft 302 according to the rotational power. Here, the plurality of rollers (306-1, 306-2, 306-3, 306-4) may be configured in a circular shape to reduce the amount of load during rotation.

The atmospheric air and circulating gas supply unit 208 supplies atmospheric air and circulating gas of 25° C. or less, and the pulverized coal pulverized by the rollers 206-1 and 206-3 is cyclone (not shown) The pulverized coal is transferred so that it can be discharged into the air. Here, the pulverized coal is raised by atmospheric air and circulating gas and transferred to the guide vane 210.

The guide vane 210 separates the transferred pulverized coal by particle size by using a centrifugal force caused by rotation, and passes only ultra-fine coal of 200 mesh (74 μm) or less among the transferred pulverized coal. Here, the granulated powder of 200 mesh (74 μm) or more of the transferred pulverized coal is lowered to be fun.

The discharge port 212 discharges the ultrafine coal passing through the guide vane 210 to a cyclone (not shown).

The rotation shaft support 214 supports the rotation shaft 202.

The roller support 216 supports the rollers 206-1 and 206-3, and additionally serves as a shell to protect the rotary shaft 202 and the rotary shaft support 214 from being pinched.

Meanwhile, the power transmission units 204-1 and 204-3 and the rollers 206-1 and 206-3 are excellent in durability, abrasion resistance, and chemical resistance so that the microwave irradiated by the microwave irradiation unit 110 is not absorbed. It is used by coating a Teflon material that transmits microwaves.In the case of the inside of the pulverizer 100, in order to prevent the occurrence of sparks caused by microwave leakage and reflection, 2~ It is coated inside with 5mm alumina (Al2O3) material.

4 is a diagram showing a detailed configuration of a microwave irradiation unit 110 according to an embodiment of the present invention.

As shown, the microwave irradiation unit 110, a magnetron 402, a tuner 404, a microwave irradiator 406, a circulator 408, a dummy rod (dummy) load) 410, one or more directional couplers 412-1, 412-2, temperature sensing device 414, temperature control device 416, power supply 418 , And a leak detector 420.

Referring to FIG. 4, the magnetron 402 generates and supplies microwaves for irradiation into the differentiator 100.

The tuner 404 performs impedance matching on microwaves supplied by the magnetron 402 in order to reduce microwaves reflected from the differentiator 100.

The microwave irradiator 406 irradiates the microwave impedance matched by the tuner 404 into the differentiator 100. Accordingly, water (surface moisture and pore moisture) contained in the raw coal and pulverized coal of the low-grade coal in the pulverizer 100 may be removed. Here, the microwave irradiator 406 may be configured in a plurality according to the size of the differentiator 100, and as shown in FIGS. 5A and 5B, a plurality of microwave irradiators 500-1, 500-2, 500-3, 500 -4) may be installed at an angle of 10 to 30° downward on the inner side of the pulverizer 100.

The circulator 408 guides the microwave reflected from the differentiator 100 to the dummy rod 410 so that the microwave reflected from the differentiator 100 does not return to the magnetron 402.

The dummy rod 410 protects the magnetron 402 by absorbing and removing microwaves reflected from the differentiator 100.

The one or more couplers 412-1 and 412-2 are formed between the tuner 404 and the circulator 408, between the circulator 408 and the dummy rod 410, and irradiated to the differentiator 100 To achieve this, the intensity of the microwave traveling to the microwave irradiator 406 and the microwave reflected from the differentiator 100 is measured, and the measurement result is provided to the temperature control device 416.

The temperature sensing device 414 measures the temperature inside the differentiator 100 and provides the measurement result to the temperature control device 416. Here, the temperature sensing device 414 uses a thermocouple shielded with Teflon-coated stainless steel in order to prevent corrosion from acidic reactants.

The temperature control device 416 controls the output of the power supply device 418 according to the measurement result from the one or more couplers 412-1 and 412-2. For example, if the intensity of the microwave reflected from the differentiator 100 is equal to or higher than a predetermined level, the intensity of the microwave reflected from the differentiator 100 is constant by stopping or reducing the output of the power supply 418. Try to stay below the level. Further, the temperature control device 416 controls the output of the power supply device 418 according to a measurement result from the temperature sensing device 414. For example, when the internal temperature of the differentiator 100 is higher than a predetermined temperature, the output of the power supply device 418 is stopped or decreased, so that the temperature in the differentiator 100 is maintained at a constant temperature.

The power supply device 418 supplies power to the magnetron 402 by controlling an output according to the control of the temperature control device 416. In addition, the power supply device 418 may supply power to the magnetron 402 by adjusting an output according to a microwave leakage detection result from the leak detector 420. Here, the output is designed to be variable up to 180W, 360W, 900W, 1260W, 1800W, and 2000W.

The leak detector 420 detects a microwave leakage around the differentiator 100 that may affect the environment of a worker, and provides a detection result to the temperature control device 416.

On the other hand, the following <Table 1> is a result of a comparison experiment of the occurrence of fire in the conventional technology and the low-grade coal pulverization system according to the embodiment of the present invention. If a fire such as spontaneous ignition does not occur, the internal temperature of the pulverizer is kept below 100℃, and when a fire occurs, the internal temperature of the pulverizer is maintained at 100℃ or higher. If so, it is considered that a fire has occurred.

Tanjong
Fire Prior art Embodiment of the present invention SM Fire (123℃) No fire (52℃) KIDECO Fire (142℃) No fire (55℃) ECO Fire (125℃) No fire (53℃)

Referring to <Table 1>, as a result of pulverizing the coal while injecting 1,000kg/hr of low-grade coal into the pulverizer according to the prior art, and injecting a high-temperature gas of 250℃ at 40m ³ /hr, all of the results applied to the experiment It can be confirmed that a fire has occurred because a temperature of 123℃ or higher has been detected in the coal type. On the other hand, according to the embodiment of the present invention, as a result of pulverizing coal while injecting 25°C of atmospheric air instead of 250°C of hot gas and irradiating a 2kW output microwave, a temperature of 55°C or less was detected in all coal types applied in the experiment. You can confirm that no fire has occurred.

As described above, the low-grade coal pulverization system according to an embodiment of the present invention uses general atmospheric air and circulating gas instead of high temperature gas of 250°C or higher as a propulsion medium for transporting pulverized coal in the pulverizer, thereby reducing the cause of spontaneous ignition in the pulverizer. By removing it, spontaneous ignition can be prevented at the source, and since it is not necessary to manufacture high-temperature gas, power required for manufacturing high-temperature gas can be reduced. In addition, by installing a microwave irradiator inclined downward on the inner side of the pulverizer to irradiate microwaves, there is an advantage in that the pulverization efficiency can be effectively increased by removing moisture in a short time. .

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of the present invention described in the claims. It will be obvious to those of ordinary skill in the field.

100: differentiator
110: microwave irradiation unit
202: rotating shaft
204-1, 204-3: power transmission unit
206-1, 206-3: roller
208: Atmospheric air and circulation gas supply
210: guide vane
212: outlet
214: rotating shaft support
216: roller support
218: coal inlet
402: magnetron
404: tuner
406: microwave irradiator
408: circulatory
410: dummy load
412-1, 412-2: coupler
414: temperature sensing device
416: temperature control device
418: power supply
420: leak detector

Claims (7)

A pulverizer using general atmospheric air and circulating gas as a propulsion medium for pulverizing and pulverizing low-grade coal and transporting pulverized pulverized coal,
Including a microwave irradiation unit for removing moisture by irradiating microwaves into the finer,
The microwave irradiation unit,
A magnetron that generates and supplies microwaves for irradiation in the differentiator,
A tuner that performs impedance matching on microwaves supplied by the magnetron,
A microwave irradiator installed at an angle of 10° to 30° in a downward direction on the inner side of the differentiator to irradiate microwaves impedance matched by the tuner into the differentiator,
A dummy rod that absorbs and removes microwaves reflected from the differentiator,
Low-grade coal pulverization system comprising a circulator for guiding microwaves reflected from the pulverizer to the dummy rod.
The method of claim 1, wherein the differentiator,
A rotating shaft that generates rotational power through rotation,
A power transmission unit that transmits rotational power generated by the rotational shaft,
A roller for pulverizing and pulverizing low-grade coal by rotating around the rotation shaft according to the rotational power transmitted by the power transmission unit,
Atmospheric air and circulating gas supply unit for supplying atmospheric air and circulating gas to transport the pulverized coal pulverized by the roller,
A guide vane for separating the transferred pulverized coal by particle size by using a centrifugal force by rotation, and passing the ultra-fine coal among the transferred pulverized coal,
Low-grade coal pulverization system, characterized in that it comprises a discharge port for discharging the ultra-fine coal passing through the guide vane to a cyclone.
The method of claim 2,
At least one of the power transmission unit and the roller is coated with a Teflon material, and the inside of the pulverizer is coated with an alumina material.
delete The method of claim 1, wherein the microwave irradiation unit,
A power supply device that supplies power to the magnetron,
A coupler that measures the intensity of microwaves reflected from the differentiator,
Further comprising a temperature control device for controlling the output of the power supply according to the measurement result from the coupler,
Here, the temperature control device, when the intensity of the microwave reflected from the pulverizer is equal to or higher than a predetermined level, the low-grade coal pulverization system, characterized in that to stop or reduce the output of the power supply.
The method of claim 1, wherein the microwave irradiation unit,
A power supply device that supplies power to the magnetron,
A temperature sensing device that measures the temperature inside the pulverizer,
Further comprising a temperature control device for controlling the output of the power supply device according to the measurement result from the temperature sensing device,
Here, the temperature control device stops or reduces the output of the power supply when the internal temperature of the differentiator is equal to or higher than a predetermined temperature,
A low-grade coal pulverization system further comprising: a leak detector that senses a microwave leakage around the pulverizer and provides a detection result to the temperature control device.
The method of claim 6,
The temperature sensing device is a low-grade coal pulverization system, characterized in that using a thermocouple shielded with Teflon-coated stainless steel.

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