KR20220103230A - Biomass solid fuel manufacturing apparatus using reheated steam - Google Patents

Abstract

The present invention relates to a drying system using counter flow superheated steam, and specifically, to a drying system using counter flow superheated steam, which includes: a kiln body into which raw materials are input; a steam heater which generates heat to change introduced saturated steam into superheated steam and discharges residual heat after a change; and a superheated steam spraying unit which is installed inside the kiln body and sprays the superheated steam to the raw materials in a counter flow over the entire cross section of the kiln body, wherein the raw materials are doubly dried by the superheated steam sprayed from the inside of the kiln body and the residual heat passing through a heating pipe.

Description

Biomass solid fuel manufacturing apparatus using reheated steam

The present invention relates to a steam drying system for drying solid fuel using superheated water vapor. More specifically, in a kiln-type solid fuel drying apparatus, superheated steam is sprayed countercurrently to the entire cross-section of the kiln body for drying fuel. And in response to this, it relates to a drying system using counter-current superheated steam for dropping a fuel to be dried using a falling blade.

In general, a thermal power plant that generates power using solid fuel such as coal burns about 180 tons of coal per 500 MW, and supplies about 37 tons of coal to a boiler per pulverizer.

In a 500MW thermal power plant using coal, approximately 6 coal storages with a capacity of approximately 500 tons are installed, of which 5 are supplied with normal coal, and the remaining 1 is a reserve that can be used for a certain period of time. It is operated as a coal storage shed.

Moreover, in thermal power plants that use coal as fuel, the standard design standard for coal is designed to use low-moisture bituminous coal of 6,080Kcal/Kg, 10% or less. Some thermal power plants use imported coal, and some sub-bituminous coals have an average moisture content of 17% or more, which lowers the combustion efficiency of the boiler. If the calorific value of the coal used with the standardized combustion limit of 5,400Kcal/Kg is low, a decrease in the amount of power generation and an increase in fuel consumption are expected due to a decrease in the combustion efficiency. Moreover, when using sub-bituminous coal, which is a high-moisture, low-calorie coal, the moisture content is higher than the design standard, so the transport system for transporting coal is not smooth. , the drift of heat distribution generated in the boiler and the operation in an abnormal state also occur. However, the use of sub-bituminous coal is gradually increasing to about 41-60% in order to reduce fuel costs in thermal power plants.

That is, in general, the steam drying apparatus sends high-pressure steam to a jacket or tube to indirectly heat the solid fuel indirectly.

The present invention is an improved invention of Korean Patent Publication No. 10-1860037 registered by the present applicant, and the conventional solid fuel such as coal evaporates volatiles when hot air of a certain temperature or higher is used during high-temperature drying. is generated and fine powder is generated, and when the volatile and fine dust reaches the ignition temperature, it ignites and burns inside.

That is, when using general heat-exchanged high-temperature dry air (oxygen concentration of 21%), drying proceeds quickly, but inflammable materials are ignited.

In order to prevent ignition of combustible materials, drying of combustible materials so far has been done using dry air at a very low temperature (60~80 degrees), or indirectly contacting the surface with steam tubes to avoid direct contact with high-temperature hot air. and dried. Drying by low-temperature air or indirect heat transfer takes a long time and the device becomes very large. It is an invention to improve the problem of excessive consumption.

Korean Patent Publication No. 2000-0033294 Korean Public Utility Model Publication No. 98-5225 Korean Patent Publication No. 10-1860037

Therefore, the present invention has been devised to solve the above problem, and it is possible to efficiently dry solid fuel by directly using the thermal energy contained in the steam by directly spraying high-temperature steam to the object to be dried using high-temperature and low-pressure superheated steam. An object of the present invention is to provide a steam drying system.

In addition, an object of the present invention is to provide a drying device that does not cause ignition of combustible materials, and is used for drying quickly by contacting high-temperature heat.

Another object of the present invention is to provide a drying apparatus using a phenomenon in which a raw material in contact with circulating air saturated with water vapor is heated, and moisture contained in the raw material is vaporized and evaporated to dryness.

According to the features of the present invention for achieving the above object, the present invention is a kiln body into which the raw material is input; a steam heater that generates heat to change the introduced steam into superheated steam, and discharges residual heat after the change; a superheated steam injection unit installed on the raw material outlet side of the kiln body and spraying the superheated steam to the raw material; A heating tube installed on the outside of the kiln body to pass the residual heat to heat the surface of the kiln body, wherein the raw material is superheated steam sprayed from the inside of the kiln body and residual heat passing through the heating tube It is possible to provide a drying system using countercurrent superheated steam, characterized in that it is double dried by

In addition, the superheated steam injection unit may be installed at the end of the kiln body, and a plurality of superheated steam nozzles may be formed in a circular cross-section.

In addition, the superheated steam spraying unit may include: a superheated steam supply unit having a plurality of superheated steam passages coupled to one end of the superheated steam nozzle; a superheated steam injection plate formed by introducing the superheated steam nozzle; It may include a main superheated steam nozzle coupled to the superheated steam passage and formed on a central axis of the superheated steam spray plate.

In addition, an insulating material may be further installed on the outer circumferential surface of the kiln body and the outer circumferential surface of the heating tube.

In addition, it may include a curved member for guiding the superheated steam to be sprayed in the center direction of the kiln body along the periphery of the end of the superheated steam spraying plate.

In addition, a vortex molding member formed between the curved member and the end of the superheated steam injection plate to induce a vortex flow to the injected heated steam; may include.

In addition, the steam heater may include a coil for changing steam into superheated steam, a burner for applying heat to the coil, and a discharge unit for discharging the residual heat after the change of steam in the coil.

In addition, one side of the coil may be connected to the superheated steam injection unit by a first pipe, and the other side of the coil may be connected to the dust removal device by a second pipe.

In addition, a relief device is further installed in the first pipe, and the relief device automatically discharges the superheated steam when the pressure increases due to the water vapor that is increased during drying in the kiln body.

In addition, a fan may be further installed in the second pipe to send the steam from which the dust is removed to the coil.

In addition, a falling blade may be further installed on the inner surface of the kiln body so that the raw material flows.

According to the drying system using counter-current superheated steam according to the present invention, a kiln body into which raw materials are input, a steam heater for generating heat to change the introduced saturated steam into superheated steam, and discharging residual heat after the change, the kiln; It is installed inside the main body and includes a steam spraying unit for spraying the superheated steam to the raw material, and a heating tube installed outside the kiln main body to pass the residual heat to heat the surface of the kiln main body, wherein the raw material is It is characterized in that it is double-dried by the superheated steam sprayed from the inside of the kiln body and the residual heat passing through the heating tube, so that the raw material can be double-dried to increase the drying efficiency, and the generated energy and the remaining Since all energy can be utilized, the drying efficiency can be increased, so that the maximum drying effect can be obtained with less energy.

In addition, through the present invention, the drying efficiency can be kept constant by forming the steam injection part in a counter flow with the current input part.

In addition, the steam injection unit has an effect of being dried through direct contact between the object to be dried and the superheated steam by injecting superheated steam in the opposite direction of the fuel inlet.

In addition, it is characterized in that an insulating material is further installed on the outer peripheral surface of the kiln main body and the outer peripheral surface of the heating tube, so that heat loss inside the kiln main body and the heating tube can be prevented.

In addition, it is possible to increase the drying effect of the raw material, characterized in that the kiln main body is further installed with a lifting falling blade so that the raw material flows freely from the top of the kiln.

In addition, when the coal is dried, the surface of the dried coal is changed to hydrophobicity, thereby preventing moisture re-adsorption.

As described above, there is an effect of the steam drying system of the present invention.

1 is a schematic diagram of a steam drying system according to a preferred embodiment of the present invention;
Figure 2 is a cross-sectional view taken along the line A-A of Figure 1;
Fig. 3 is a cross-sectional view taken along line BB of Fig. 1;
4 is a cross-sectional view CC of FIG. 1 and a detailed view of the superheated steam injection unit.
Fig. 5 is a schematic view of the cooling device of Fig. 1;
6 is a DD cross-sectional view of FIG.

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, since the embodiment described in this specification is only the most preferred embodiment of the present invention and does not represent all the technical spirit of the present invention, there are various equivalents and modifications that can be substituted for them at the time of the present application. It should be understood that

1 is a schematic diagram of a steam drying system according to a preferred embodiment of the present invention, FIG. 2 is a cross-sectional view A-A, FIG. 3 is a cross-sectional view B-B of FIG. 1, FIG. 4 is a cross-sectional view C-C, FIG. 6 is a D-D cross-sectional view of FIG. 5 .

The steam drying system of the present invention includes a kiln body (1) into which raw materials are input, a steam heater (4) that generates heat to change the introduced saturated steam into superheated steam, and discharges residual heat after the change, and the kiln body (1) is installed on the inside of the steam injection part 3 for spraying the superheated steam to the raw material, is installed on the outside of the kiln body (1) and passes the residual heat to the surface of the kiln body (1) It includes a heating tube (2) for heating, the raw material is characterized in that it is double dried by the superheated steam sprayed from the inside of the kiln body (1) and residual heat passing through the heating tube (2).

The kiln body 1 is a rotary furnace in the form of a cylinder.

The raw material is put inside the kiln body (1).

More precisely, as shown in FIG. 2 , the raw material is input from the left side of the kiln body 1 , and after the raw material is dried inside the kiln body 1 , it is installed on the right side of the kiln body 1 . It is discharged to the outside through the discharge device (9).

The raw material is a solid fuel such as coal.

The raw material is double dried by the superheated steam injected from the inside of the kiln body 1 and the residual heat passing through the heating tube 2 to be described later.

These raw materials are ignited by the fuel component during drying and carbonization, and as in the present invention, when heated using high-temperature steam, there is an advantage that the ignition of the fuel can be prevented.

That is, when solid fuel is dried, high-temperature hot air has a risk of ignition, so high-temperature steam is used, and high-temperature steam is directly injected at low pressure toward the raw material flowing inside the kiln body 1 .

As shown in FIG. 3 , the kiln body 1 is rotated clockwise or counterclockwise by the driving unit 11 , and as the angle of repose of the raw material rising on the inner wall of the kiln body 1 is collapsed, the kiln It falls in the vertical direction from the inside of the main body (1).

The rotation direction of the kiln body 1 is preferably the same as the movement direction of the exhaust gas passing through the heating tube 2 to be described later.

In addition, the kiln body 1 is preferably installed to be inclined. More precisely, the raw material inlet in the kiln body 1 is installed higher than the raw material outlet. Thus, the raw material input from the raw material inlet by the rotation of the kiln body 1 is easily discharged to the raw material outlet while being dried in the kiln main body 1 .

Although it is appropriate that the driving unit 11 is a directly connected reducer type, any driving unit for rotating a cylindrical rotary furnace may be used.

A drop blade 12 is further installed on the inner surface of the kiln body 1 to facilitate the flow of the raw material.

The falling blade 12 has the advantage of smoothing the flow of the raw material injected into the inside of the kiln body (1).

A superheated steam injection part 3 to be described later is installed inside the kiln body 1 , and a heating tube 2 to be described later is installed outside the kiln body 1 .

The kiln body 1 is preferably formed to be inclined. More precisely, as for the kiln body 1, it is preferable that the part where the raw material is input is higher than the part where the raw material is discharged. Accordingly, the raw material moves from the input part to the discharge part by rotation.

An insulating material 100 is further installed on the outer circumferential surface of the kiln body 1 .

Thus, there is an advantage that the heat inside the kiln body 1 can be prevented from being emitted to the outside by the insulating material 100 .

A dust removal device 5 to be described later is further installed at the inlet of the kiln body 1 to remove the dust contained in the superheated steam flowing into the kiln body 1 .

Combustion air exhausted after heat exchange is exhausted with a large amount of heat (energy) depending on the exhaust temperature.

At this time, the exhausted combustion gas is supplied to the heating jacket surrounding the outer cylinder of the drying device to heat the outer cylinder of the dryer, and the raw material inside is indirectly heated by the continuous transmission of the heated outer cylinder of the dryer.

This saves a lot of energy because the wasted energy is reused.

The drying device has a lifting flight that puts the raw material inside and pulls it up according to the rotation of the dryer body and then drops it at a certain position. will be different

It is raised up according to the rotation of the fuselage and then repeatedly falls from a certain position by the falling wings, and it shows a shape similar to that of a waterfall, so this is called the cascade effect.

The raw material is dropped from the top, the surface of each particle is exposed, and the exposed surface is heated in contact with drying air (heating steam) and dried.

The heating tube 2 is installed outside the kiln body 1 .

More precisely, the heating tube 2 is installed on the outer peripheral surface of the kiln body 1 .

The heating tube 2 heats the surface of the kiln body 1 by passing the heat discharged from the steam heater 4 to be described later.

This heat means residual heat after the change of steam in the steam heater 4 to be described later.

That is, since the surface of the kiln body 1 is heated again with the residual heat after using the heat source for changing the saturated steam to the superheated steam for high-temperature steam heating, the energy efficiency can be increased by recycling the heat source (energy). have.

The heating tube 2 includes a heat inlet 21 through which heat is introduced and a heat outlet 22 through which heat is discharged.

An insulating material 100 is further installed on the outer circumferential surface of the heating tube 2 .

Thus, there is an advantage that the heat inside the kiln body 1 can be prevented from being emitted to the outside by the insulating material 100 .

This insulating material 100 is the same as the insulating material 100 installed in the kiln body (1).

The steam heater 4 generates heat to change the introduced saturated steam to superheated steam, and to discharge residual heat after the change.

The residual heat is exhaust residual heat exhausted after converting the saturated steam into the superheated steam.

The steam heater 4 includes a heater body 41 , a coil 42 installed on the heater body 41 , and a burner 43 installed under the heater body 41 .

The heater body 41 has a rectangular parallelepiped shape, and is narrower from the top to the top.

A burner 43 is installed under the heater body 41 .

The burner 43 applies heat to the coil 42 to be described later.

A coil 42 is installed inside the heater body 41 .

Steam moves inside the coil 42 , and the saturated steam is changed into superheated steam by the heat generated by the burner 43 .

That is, as the saturated steam changes into superheated steam in the heated coil 42 , the pressure increases, which serves to lower the pressure again through pressure control. In addition, while the pressure of the superheated steam is kept constant, the superheated steam, which is a low pressure, is sprayed at a constant pressure through the spray nozzle, and comes into direct contact with the dry raw material.

The temperature of such superheated steam is preferably between 300°C and 500°C.

One side of the coil 42 is connected to a superheated steam injection unit 3 to be described later by a first pipe 71 , and the other side of the coil 42 is a second pipe 72 by a second pipe 72 to remove dust. (5) is connected.

A relief device 8 is further installed in the first pipe 71 .

The relief device 8 automatically discharges the superheated steam when the pressure in the kiln body 1 increases. More precisely, when the amount of water vapor generated during drying of the raw material in the kiln body 1 increases and the internal pressure of the kiln body 1 increases to a certain pressure or more, the superheated steam is automatically discharged.

The internal pressure may be atmospheric pressure. It may be preferably 0.1 bar to 30 bar, and more preferably 1 bar to 5 bar.

If the pressure condition is out of the above conditions, drying efficiency may be lowered.

Saturated steam from which dust and scattering is removed moves to the second pipe 72 .

A fan 6 is further installed in the second pipe 72 .

The fan 6 sends the saturated steam from which the dust has been removed to the coil 42 .

A discharge part 44 is formed at an upper end of the heater body 41 .

The discharge unit 44 discharges residual heat after being used for steam change in the coil 42 .

The discharge part 44 is connected to the heating tube 2 by a third pipe 73 . More precisely, the outlet 44 is connected to the inlet 31 of the heating tube 2 by the third pipe 73 .

The steam injection unit 3 is installed at one end of the kiln body 1 .

Preferably, it may be installed at the fuel outlet side of the kiln body, and may be installed to form a flow opposite to the movement direction of the fuel.

The vapor injection unit 3 includes a plurality of nozzles.

The superheated steam injection unit may be installed at an end of the kiln body, and a plurality of superheated steam nozzles may be formed in a circular cross-section.

In addition, the superheated steam injection unit may include: a superheated steam supply unit having a plurality of superheated steam passages coupled to one end of the superheated steam nozzle; a superheated steam injection plate formed by introducing the superheated steam nozzle; It may include a main superheated steam nozzle coupled to the superheated steam passage and formed on a central axis of the superheated steam spray plate. The pressure of such a nozzle is preferably 0.0005 bar or less. Thus, there is an advantage that it is possible to prevent the scattering of the raw material in the powder state.

The injection pressure of these nozzles is preferably between 100 mmH ₂ O and 500 mmH ₂ O. The reason is that high-pressure steam is directly sprayed on the injected raw material, and small particles and dust generated at this time are scattered and discharged to the dust removal device 5 to be described later.

Thus, it is possible to maintain a constant injection pressure of the superheated steam injected from the nozzle. That is, in order to compensate for the pressure lowered by the nozzle, the pressure is made constant through the pressure control device.

The dust removal device 5 is installed at the inlet of the kiln body 1 .

The dust removal device 5 is to remove the dust contained in the superheated steam flowing into the inside of the kiln body (1).

More precisely, the dust contained in the superheated steam and the dust contained in the water vapor contained in the raw material injected into the kiln body 1 are also removed.

It is preferable that this dust removal device 5 is two or more cyclones. Thus, there is an advantage in that it is possible to efficiently remove the dust contained in the superheated steam and the dust contained in the water vapor contained in the raw material.

Such a steam drying system has an advantage that energy efficiency can be increased by recycling energy in a closed cycle cycle.

Hereinafter, the operation of the present embodiment having the above-described configuration will be described.

The raw material is put into the kiln body (1).

The steam heater (4) generates heat to change the saturated steam into superheated steam, and the residual heat after the change is discharged to the heating tube (2).

The superheated steam introduced into the superheated steam spraying unit is sprayed onto the falling raw material while covering the cross-sectional area of the kiln body by the falling blades to dry the raw material, and is double dried by residual heat moving the heating tube (2).

Part of the superheated steam flowing into the steam injection unit 3 and the steam generated during drying of the raw material moves to the dust removal device 5 to remove the dust.

After dust removal, the saturated steam moves to the steam heater (4) by the fan (6).

Heat is generated in the steam heater (4), and the above operation is repeated.

When using circulating heating steam at 400-500 degrees Celsius, the surface temperature of the drying coal is heated to 250-300 degrees Celsius, and the surface of the coal is modified and converted from hydrophilicity to hydrophobicity - which is left outside Therefore, it does not absorb moisture again even when it rains, so it is safe to store it outside.

Also, when converted to hydrophobic particles, spontaneous combustion in the atmosphere is prevented.

If the raw material is stored outside in summer before drying, the internal temperature rises to 69 degrees, and spontaneous ignition occurs at this time.

Products dried by hot steam by this drying device do not rise above 45 degrees even when left under the same conditions, and spontaneous ignition does not occur.

Coal dried using this dryer can form HCK of Korea Institute of Energy Research.

Accordingly, it is a device for drying combustible materials that spontaneously ignite at high temperatures, such as coal, wood chips, sawdust, and the like.

Spontaneous ignition is possible only in the presence of oxygen in the air, and in the absence of oxygen, it uses the principle that it does not ignite even at high temperatures.

Combustible raw materials that are easily ignited can be dried at a very low temperature when dried using dry air, and it takes a long time to dry.

It is dried using heated high-temperature steam to dilute the oxygen concentration so that high-temperature drying is possible.

Steam supplies boiler steam during initial preheating.

At this time, the oxygen concentration of the circulating air is measured, and steam is supplied until it is 5% or less, and preheated.

When preheating is completed and the oxygen concentration is less than 5%, combustible raw materials such as coal are supplied.

The moisture contained in the combustible raw material evaporates, and the water vapor in the circulating air becomes saturated, and the oxygen concentration is maintained below 3%.

That is, the raw material is dried and the discharged water vapor remains in the continuously circulating heated air and is converted into saturated water vapor.

If the temperature of the steam to be heated is maintained at 300 degrees or higher, heat transfer to the raw material is facilitated, and the moisture contained in the raw material is evaporated and included in the circulating air.

Water vapor generated during drying from raw materials is discharged to the outside by measuring the internal pressure, etc.

The steam heater heats the circulating steam using an indirect heat exchange tube for combustion air burned in a burner.

The heated water vapor transfers heat to the raw material, and a part is cooled. At this time, when cooled below the dew point, it is condensed and converted back to water.

The circulating water vapor must be maintained at a temperature above the dew point.

In general, the temperature of the recirculated steam after drying is maintained above 100 degrees.

Compared to the conventional discharge of air at 100 degrees to the outside, because the air of 100 degrees is reheated and circulated, the heating energy is used as small as that.

In fact, I was concerned that the steam would evaporate again due to the saturated steam, but as a result of drying the coal with 20% surface moisture and 8% crystal moisture, the surface moisture was dried up to 5%.

The cooling device may be a rotary drum cooler.

The cooling device passes high-temperature raw materials through the inside of the rotating drum, and the raw material flowing inside rises up on the inner surface of the drum, and when it rises to the height of the angle of repose, it slides and flows down the surface of the raw material.

At this time, cooling water is sprayed to the outside of the rotating rotary drum to cool the outer surface of the drum.

A jacket-shaped outer plate is formed on the surface of the drum where the coolant is sprayed to prevent the coolant from scattering or the steam vaporized by the temperature from being discharged to the outside. Exhaust to the outside through the exhaust port and exhaust fan.

Cooling water is used by circulating after cooling through a cooling tower.

The temperature conditions mentioned in the above specification are Celsius conditions.

As described above, although exemplary embodiments of the present invention have been illustrated and described, various modifications and other embodiments may be made by those skilled in the art. All such modifications and other embodiments are intended to be contemplated and encompassed by the appended claims, without departing from the true spirit and scope of the present invention.

1: Kiln body 11: Drive part
12: fall wing 2: heating tube
21: heat inlet 22: heat outlet
3: superheated steam injection part 31: inlet
32: outlet 33: nozzle unit
34: Section 1 35: Section 2
4: steam heater 41: heater body
42: coil 43: burner
44: discharge part 5: dust removal device
6: fan 71: first pipe
72: second pipe 73: third pipe
8: Relief device 9: Discharge device
10: chiller
100: insulation

Claims (10)

The kiln body into which the raw material is input;
a steam heater that generates heat to change the introduced steam into superheated steam, and discharges residual heat after the change;
a superheated steam injection unit installed on the raw material outlet side of the kiln body and spraying the superheated steam to the raw material;
It includes a; heating tube installed outside the kiln body to heat the surface of the kiln body by passing the residual heat,
The drying system using counter-current superheated steam, characterized in that the raw material is double dried by the superheated steam sprayed from the inside of the kiln body and the residual heat passing through the heating tube.
The method according to claim 1,
The superheated steam injection part is installed at the end of the kiln body,
A drying system using counterflow superheated steam, characterized in that a plurality of superheated steam nozzles are formed in a circular cross section.
3. The method according to claim 2,
The superheated steam injection unit may include: a superheated steam supply unit having a plurality of superheated steam passages coupled to one end of the superheated steam nozzle;
a superheated steam injection plate formed by introducing the superheated steam nozzle;
and a main superheated steam nozzle coupled to the superheated steam flow path and formed on the central axis of the superheated steam injection plate.
The method according to claim 1,
A drying system using countercurrent superheated steam, characterized in that an insulating material is further installed on the outer peripheral surface of the kiln body and the outer peripheral surface of the heating tube.
4. The method of claim 3,
and a curved member for guiding the superheated steam to be sprayed toward the center of the kiln body along the periphery of the end of the superheated steam spraying plate.
6. The method of claim 5,
and a vortex forming member formed between the curved member and an end of the superheated steam spray plate to induce a vortex flow to the sprayed heated steam.
6. The method of claim 5,
The steam heater includes a coil for changing steam into superheated steam, a burner for applying heat to the coil, and a discharge unit for discharging the residual heat after the change of steam in the coil,
One side of the coil is connected to the superheated steam injection unit by a first pipe, and the other side of the coil is connected to the dust removal device by a second pipe.
8. The method of claim 7,
A relief device is further installed in the first pipe,
The relief device is a drying system using counter-current superheated steam, characterized in that the superheated steam is automatically discharged when the pressure is increased due to the increased water vapor during drying in the kiln body.
9. The method of claim 8,
A drying system using counter-current superheated steam, characterized in that a fan is further installed in the second pipe to send the dust-removed steam to the coil.
The method according to claim 1,
A drying system using counter-current superheated steam, characterized in that a drop blade is further installed on the inner surface of the kiln body so that the raw material flows.

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