JP6322509B2 - Modified coal production method and modified coal production apparatus - Google Patents

Description

  The present invention relates to a method for producing modified coal for producing modified coal from high-moisture coal, and an apparatus for producing modified coal.

In recent years, coal with high water content such as lignite and bituminous coal (high moisture coal) is dried and dry-distilled, etc., and the fuel ratio is adjusted from 2 to 4, which is equivalent to low volatile steam coal. A method for producing reformed coal to be a good fuel is being studied. In addition, the fuel ratio said here means the weight ratio of the fixed carbon part with bad combustibility with respect to the volatile matter with good combustibility in coal. The reformed coal having a fuel ratio of 2 to 4 is used by being burned for power generation at a power plant, for example.
In the method for producing modified coal from this type of high moisture coal, drying of the high moisture coal is important, and the following methods are known as the drying method.

  For example, Patent Document 1 describes a method for improving the fluidization of a dryer by providing a preheating device for drying high moisture coal. Patent Document 2 discloses that steam discharged from a drying apparatus is compressed and used for drying high-moisture coal, and steam drain from the drying apparatus is used for preheating drying. In addition to these, there is a WTA method described in Non-Patent Document 1 as a similar drying method.

JP 2013-178026 A JP 2013-178028 A

"A modern process for treating and drying lignite", WTA TECHNOLOGY, [Search June 12, 2014], Internet <URL: https://www.rwe.com/web/cms/mediablob/en/234566/data / 213182/6 / rwe-power-ag / innovations / coal-innovation-centre / fluidized-bed-drying-with-internal-waste-heat-utilization-wta / Brochure-WTA-Technology-A-modern-process-for -treating-and-drying-lignite.pdf>

Brown coal, which is representative of high-moisture coal, has the property of being easily ignited (spontaneously ignited) when the water content is reduced. For example, when high-moisture coal is indirectly heated with water vapor, and the high-moisture coal containing 50 to 60% of moisture by mass ratio is dried to the extent of containing 10% of moisture by mass ratio, As a countermeasure against ignition, a method of drying in a water vapor atmosphere without oxygen has been put into practical use.
However, in order to heat and dry high-moisture coal, a large amount of steam for heating is required. For this reason, if high moisture coal is not dried using cheap water vapor | steam, the drying cost of high moisture coal will become high, and there exists a problem that the manufacturing cost of reformed coal will also become high correspondingly.

Therefore, as a method for securing a large amount of steam for heating, the steam evaporated during drying of the high moisture coal is compressed, and this compressed steam is used for drying of the high moisture coal. A method for reducing the amount of water vapor from the outside has been developed.
However, in order to compress water vapor, an expensive compressor and enormous electric power for compression are required. Therefore, the steam for drying the high moisture coal obtained by this method is not inexpensive.
The present invention has been made in view of such problems, and can dry high-moisture coal without igniting it, and can obtain water vapor for drying high-moisture coal at low cost. It is an object of the present invention to provide a method for producing modified coal and an apparatus for producing modified coal that can reduce the amount of water vapor for drying the coal.

In order to solve the above problems, the present invention proposes the following means.
The modified coal production method of the present invention is a modified coal production method for producing modified coal from high-moisture coal, which is coal containing 45% or more of water by mass ratio, from the high-moisture coal A drying step of evaporating moisture to form dry coal, a dry distillation step of carbonizing the dry coal after the drying step to form the modified coal, and cooling for cooling the modified coal after the dry distillation step A step of heating the air taken from outside, fluidizing the high moisture coal with the air to form a coal fluidized bed, and from the high moisture coal in the coal fluidized bed to the moisture After the air fluidized bed drying step and the air fluidized bed drying step, the primary dry coal is indirectly heated to evaporate the moisture from the primary dry coal and to dry the primary fluidized coal. Coal and evaporated Indirect heating and drying step of recovering water vapor, an indirect heating and drying step, and in the dry distillation step, the dry coal is subjected to dry distillation, and combustion after supplying dry distillation heat necessary for dry distillation of the dry coal Dry distillation process steam is recovered by exhaust heat recovery using exhaust gas, and in the air fluidized bed drying process, the air taken from the outside is indirectly heated with the indirect heating drying process steam, and in the indirect heating drying process The dry distillation steam is used to indirectly heat primary dry coal.

  Moreover, the modified coal production apparatus of the present invention is a modified coal production apparatus for producing modified coal from high-moisture coal, which is coal containing water at a mass ratio of 45% or more. A drying unit that evaporates the water to form dry coal, a dry distillation unit that carbonizes the dry coal to form the modified coal, and a cooling unit that cools the modified coal, and the drying unit includes Heating the air taken from the outside, fluidizing the high-moisture coal with the air to form a coal fluidized bed, and evaporating the moisture from the high-moisture coal in the coal fluidized bed to form primary dry coal A first drying unit, indirectly heating the primary dry coal, evaporating the water from the primary dry coal to form the dry coal, and recovering steam by the indirect heat drying process, which is the evaporated water; Two drying sections, In the first drying section, the dry coal is recovered by exhaust heat recovery using the combustion exhaust gas after carbonizing the dry coal and supplying the carbonization heat necessary for carbonization of the dry coal. The dry distillation process steam is used to indirectly heat the taken-in air with the indirectly heated drying process steam and indirectly heat the primary dry coal in the second drying section.

Moreover, in said manufacturing method of modified coal, it is more preferable to heat indirectly the inside of the said coal fluidized bed with the said indirect heating drying process water vapor | steam in the said air fluidized bed drying process.
Moreover, in said modified coal manufacturing apparatus, it is more preferable to heat the inside of the said coal fluidized bed indirectly with the said indirect heating drying process water vapor | steam in said 1st drying part.

In the modified coal manufacturing method, the primary drying is performed after the high moisture coal becomes the primary dry coal with respect to the amount of water evaporated from the high moisture coal in the air fluidized bed drying step. More preferably, the amount of water evaporated from the coal in the indirect heat drying step is twice.
In the modified coal manufacturing method, it is more preferable that the air taken in from the outside is indirectly heated with the dry distillation steam in the air fluidized bed drying process.

  According to the modified coal production method and modified coal production apparatus of the present invention, high moisture coal can be dried without igniting, and steam for drying the high moisture coal can be obtained at low cost. The amount of water vapor for drying the moisture coal can also be reduced.

It is a block diagram of the manufacturing apparatus of the modified coal of 1st Embodiment of this invention. It is a block diagram of the carbonization equipment of the manufacturing apparatus of the modified coal. It is a flowchart which shows the manufacturing method of the modified coal of this embodiment. It is an operation diagram which shows drying operation of an air fluidized bed drying process based on the low temperature humidity chart with respect to air and water. It is a block diagram of the manufacturing apparatus of the modified coal of 2nd Embodiment of this invention.

(First embodiment)
Hereinafter, a first embodiment of a modified coal production apparatus (hereinafter also abbreviated as “production apparatus”) according to the present invention will be described with reference to FIGS. 1 to 4.
As shown in FIG. 1, the manufacturing apparatus 1 according to the present embodiment includes a drying facility (drying unit) 10 that evaporates moisture from a high-moisture coal M1 to dry coal M3, and dry coal from which moisture has evaporated in the drying facility 10. A dry distillation facility (dry distillation unit) 30 that carbonizes M3 into reformed coal M4 and a cooling facility (cooling unit) 40 that cools the modified coal M4 obtained by the dry distillation facility 30 are provided.
In addition, the high moisture coal M1 said here means the coal which contains a water | moisture content 45% or more by mass ratio. Reference numerals M3 and M4 and reference numeral M2 to be described later do not mean piping, but mean dry coal, reformed coal, and primary dry coal (not shown) supplied by these pipes.

The drying facility 10 heats the air M5 taken from the outside, fluidizes the high-moisture coal M1 with the heated air M5, performs a drying operation as a coal fluidized bed M6, and sets it as the primary dry coal M2. The drying equipment (first drying section) 11 and the primary dry coal M2 treated by the first drying equipment 11 are indirectly heated with a later-described dry distillation process steam to evaporate water from the primary dry coal M2 to dry coal. And a second drying facility (second drying section) M3.
The first drying equipment 11 includes an air fan 15 that takes in air M5 from the outside, an air preheater 16 that heats the air M5 taken in by the air fan 15, and air heating that further heats the air M5 heated by the air preheater 16. And an air fluidized bed dryer 18 to which air M5 heated by the air heater 17 is supplied.
The air fluidized bed dryer 18 is supplied with high moisture coal M1 at a constant predetermined weight per hour.
Connected to the air fluidized bed dryer 18 is an exhaust air dust collector 19 for recovering coal fines accompanying the exhaust air.

A heating pipe (heating pipe) 22 that is connected (communication) to one end of the second water vapor supply pipe 21 is disposed in the second drying facility 12. The other end of the second water vapor supply pipe 21 is connected to the dry distillation facility 30. At the end of the heating pipe 22 on the side not connected to the second water vapor supply pipe 21, steam condensed water is collected in a pipe under substantially atmospheric pressure, and is returned as steam condensate as necessary.
The second drying facility 12 is connected to the air fluidized bed dryer 18 of the first drying facility 11. The primary dry coal M <b> 2 supplied from the air fluidized bed dryer 18 into the second drying facility 12 is heated by contacting the outer surface of the heating pipe 22 installed inside the second drying facility 12, and primary dried coal. It is dried by evaporating the water in M2. The pipe 23 branches from the second water vapor supply pipe 21 and is connected to the air heater 17.
In order to heat the air M <b> 5 taken from the outside by the air heater 17, water vapor (dry distillation process steam described later) is supplied to the air heater 17 through the pipe 23.

  One end of a first water vapor supply pipe 24 is connected to the second drying facility 12. The other end portion of the first water vapor supply pipe 24 extends to the air preheater 16, and the indirectly heated drying process water vapor is supplied to the air preheater 16 through the first water vapor supply pipe 24. The air M5 taken from the outside is indirectly heated by the indirect heating drying process steam in the air preheater 16.

As shown in FIG. 2, the carbonization facility 30 includes, for example, a known external heat type rotary kiln 31, a secondary combustion device 32 connected to the kiln 31, a steam generation device 33 connected to the secondary combustion device 32, A dust removal device 34 connected to the steam generation device 33, a suction fan 35 connected to the dust removal device 34, and an exhaust gas treatment device 36 connected to the suction fan 35 are included.
The kiln 31 is connected to the second drying facility 12 of the drying facility 10. In the kiln 31, dry coal M3 is subjected to dry distillation in an environment of several hundreds of degrees Celsius where oxygen is not present to obtain reformed coal M4. The reformed coal M4 is supplied to the cooling facility 40. The description of the secondary combustion device 32, the steam generation device 33, the dust removal device 34, the suction fan 35, and the exhaust gas treatment device 36 will be described later.
The cooling facility 40 cools the reformed coal M4 carbonized by the carbonization facility 30 to a temperature at which it does not ignite by contact oxidation with air, for example, several tens of degrees centigrade.

Next, a method for manufacturing the modified coal M4 of the present embodiment (hereinafter, also abbreviated as “manufacturing method”) using the manufacturing apparatus 1 configured as described above will be described.
FIG. 3 is a flowchart showing the manufacturing method of this embodiment. This production method includes a drying step S10 in which moisture is evaporated from the high-moisture coal M1 to obtain dry coal M3, a dry distillation step S20 in which dry coal M3 is subjected to dry distillation after the drying step S10 to obtain reformed coal M4, And a cooling step S30 for cooling the modified coal M4 after the step S20.
The drying step S10 heats the air M5 taken from the outside, fluidizes the high moisture coal M1 with the air M5, evaporates and dries the moisture as the coal fluidized bed M6, and obtains the primary dry coal M2 by air fluidized bed drying. After the step S11 and the air fluidized bed drying step S11, there is an indirect heating drying step S12 in which moisture is evaporated from the primary dry coal M2 to obtain dry coal M3.

In the air fluidized bed drying step S <b> 11, air M <b> 5 is taken in from the outside by the air fan 15.
As will be described later, the indirect heating drying process steam is supplied to the air preheater 16 through the pipe of the first steam supply pipe 24. The taken-in air M5 is indirectly heated by contacting the outer surface of the first water vapor supply pipe 24 in the air preheater 16.
The air M5 heated by the air preheater 16 is further supplied to the air heater 17, and the dry distillation process steam is supplied to the air heater 17 through the pipe line 23 as described later. The taken-in air M5 is indirectly heated by the dry distillation process steam by contacting the outer surface of the pipe 23 in the air heater 17. That is, the air M5 heated by the air preheater 16 is further indirectly heated by the air heater 17. The indirectly heated drying process steam and the dry distillation process steam used in the air preheater 16 and the air heater 17 are discharged to the outside as steam condensed water, or returned as steam condensate as necessary.

In the above description, the air M5 is indirectly heated by contacting the outer surface of the first water vapor supply pipe 24 and the outer surface of the pipe 23 in the air preheater 16 and the air heater 17, respectively. However, the configuration for indirectly heating the air M5 is not limited to the pipes 24 and 23. For example, an indirect heat exchanger such as a multi-tube type (shell and tube type) or a plate type is appropriately selected. Can be used.
The same applies to the heating tube 22 of the second drying facility 12 and the heating tube 52 of the air fluidized bed dryer 18 described later.

The air M5 heated by the air heater 17 is supplied to the air fluidized bed dryer 18. The temperature of the air M5 when it is supplied to the air fluidized bed dryer 18 may be a temperature that does not reach the ignition temperature even when the high-moisture coal M1 generates heat by oxidation, and is 120 ° C. or less from the viewpoint of preventing ignition. preferable.
The air fluidized bed dryer 18 is supplied with high moisture coal M1. The average particle diameter of the high moisture coal M1 is, for example, 3 mm. In this example, the high-moisture coal M1 before performing the air fluidized bed drying step S11 supplied to the air fluidized bed dryer 18 contains, for example, 60% of water by mass, and the remaining 40% is composed of volatile matter. The fixed carbon content is about 20% each, and some ash.

The high-moisture coal M1 supplied to the air fluidized bed dryer 18 is fluidized by the air M5 supplied to the air fluidized bed dryer 18 to become a coal fluidized bed M6. When the high moisture coal M1 in the coal fluidized bed M6 is heated by the heated air M5, the moisture evaporates from the high moisture coal M1, and the air M5 is humidified with the evaporated moisture from the high moisture coal M1. To do. On the other hand, the coal fluidized bed M6 becomes the primary dry coal M2 as the water evaporates from the high moisture coal M1.
Note that the exhausted air that has been humidified by the air fluidized bed dryer 18 is separated from the exhausted air dust and the air-entrained coal fines by the exhausted air dust collector 19. The entrained coal fines and the like separated by the exhaust air dust collector 19 are collected, granulated as necessary, and returned to the primary dry coal M2. On the other hand, air is discharged as exhaust air.

The temperature inside the coal fluidized bed M6 of the air fluidized bed dryer 18 is desirably a temperature at which the high moisture coal M1 does not generate oxidation heat due to oxygen in the air M5, and is preferably 60 ° C. or less. That is, the air fluidized bed dryer 18 is a range until the water content decreases to 20% by weight, for example, in the constant rate drying speed region before the water content of the primary dry coal M2 reaches the limit water content. A drying operation is preferred. Even when the primary dry coal M2 is dried to a moisture content lower than the limit moisture content, it is preferable to dry the high moisture coal M1 at a relatively low coal fluidized bed M6 internal temperature of 60 ° C. or less.
When the drying operation of the coal fluidized bed M6 in the air fluidized bed dryer 18 is finished, the air fluidized bed drying step S11 is finished, the process proceeds to the indirect heating drying step S12, and the primary drying processed in the air fluidized bed dryer 18 is performed. Coal M2 is supplied to the second drying facility 12.

In the indirect heating drying step S <b> 12, the primary dry coal M <b> 2 is indirectly heated through the heating pipe 22 by the dry distillation process steam supplied through the pipe line of the second steam supply pipe 21 in the second drying equipment 12. In the second drying facility 12, the primary dry coal M <b> 2 is indirectly heated by contacting the outer surface of the heating pipe 22. In the indirect heat drying step S12, the primary dry coal M2 is dried in a steam atmosphere as in the conventional case.
When the primary dry coal M2 is heated by the heating pipe 22 disposed in the second drying facility 12, moisture evaporates from the primary dry coal M2.

In the drying step S10, drying is performed until the high moisture coal M1 becomes dry coal M3. The amount of water that evaporates until the primary dry coal M2 becomes dry coal M3 in the indirect heat drying step S12 is the total amount of water vapor that is obtained from the water evaporated in the indirect heat drying step S12, and air fluidized bed drying. In the step S11, it is preferable from the viewpoint of thermal efficiency to set so that the total amount of steam required for drying from the high moisture coal M1 to the primary dry coal M2 is balanced (equal). After a certain amount of the high moisture coal M1 becomes the primary dry coal M2 in the air fluidized bed drying step S11 with respect to the amount of moisture evaporated from the fixed amount of high moisture coal M1 in the air fluidized bed drying step S11, It is preferable that the amount of water evaporated from the primary dry coal M2 in the indirect heat drying step S12 is twice.
That is, for example, when drying the high moisture coal M1 having a moisture content of 60% by weight in the drying step S10 until the dry coal M3 having a moisture content of 10% by weight is dried, the air fluidized bed drying step. In S11, it is preferable to dry the high moisture coal M1 having a moisture content of 60% by weight to obtain a primary dry coal M2 having a moisture content of 50% by weight.

The temperature of the air M5 when supplied to the air fluidized bed dryer 18 is 120 ° C. or less, the temperature inside the air fluidized bed dryer 18 is 60 ° C. or less, and primary drying at the end of the air fluidized bed drying step S11. By setting the moisture content of the coal M2 to 50% by weight, the high-moisture coal M1 can be dried without being ignited even in an air M5 atmosphere in the air fluidized bed drying step S11.
The dry distillation process steam supplied to the heating pipe 22 installed in the second drying facility 12 through the pipe of the second steam supply pipe 21 is condensed in the heating pipe 22 and discharged as steam condensed water.
Indirect heating and drying process steam, which is water evaporated from the primary dry coal M2, is collected and supplied to the air preheater 16 through the first steam supply pipe 24. That is, as shown in FIG. 3, the indirect heat drying step water vapor obtained in the indirect heat drying step S12 is used in the air fluidized bed drying step S11.
When the drying process of the primary dry coal M2 in the second drying facility 12 is completed and the dry coal M3 is manufactured, the dry coal M3 manufactured in the second drying facility 12 is supplied to the dry distillation facility 30 and the indirect heating drying step S12. And the process proceeds to the carbonization step S20.

In the carbonization step S20, the dry coal M3 is carbonized as described above in the carbonization facility 30. In this dry distillation operation, the volatile matter of the dry coal M3 is thermally decomposed in the externally heated rotary kiln 31 shown in FIG. The generated gas and tar content are returned to the kiln 31 and burned by the air supplied to the kiln 31, thereby obtaining the amount of heat (dry distillation heat) necessary for dry distillation of the dry coal M3. This dry distillation heat is supplied to the kiln 31.
The gas and tar remaining without being burned in the kiln 31 are supplied from the kiln 31 to the secondary combustion device 32. By burning the gas and tar components more completely in the secondary combustion device 32, a high-temperature combustion exhaust gas can be obtained. In the steam generator 33, exhaust heat recovery is performed using this combustion exhaust gas to obtain dry distillation process steam.
The dry distillation steam may be low-pressure steam at a relatively low pressure (0.4 MPaG (megapascal gauge) or more). The combustion exhaust gas is sucked by the suction fan 35 through the dust removing process by the dust removing device 34. Further, the combustion exhaust gas is exhausted from the dry distillation equipment 30 through exhaust gas treatment such as desulfurization by the exhaust gas treatment device 36.

As shown in FIG. 1, the carbonization process steam passes through the second steam supply pipe 21 and the heating pipe 22 and is supplied to the second drying equipment 12. That is, as shown in FIG. 3, the dry distillation steam obtained in the dry distillation step S20 is used in the indirect heating drying step S12.
A part of the dry distillation process steam flowing through the second steam supply pipe 21 is supplied to the air heater 17 through a pipe line of the pipe 23 shown in FIG.
When the production of the reformed coal M4 in the dry distillation facility 30 is completed, the reformed coal M4 manufactured in the dry distillation facility 30 is supplied to the cooling facility 40, the dry distillation step S20 is terminated, and the process proceeds to the cooling step S30.
Note that the temperature of the reformed coal M4 when the carbonization step S20 is completed is preferably 400 ° C. or more and 650 ° C. or less, more preferably 450 ° C. or more and 600 ° C. or less, with respect to the fuel ratio of 2 to 4. preferable.

In the cooling step S30, the modified coal M4 produced by the dry distillation equipment 30 is cooled to about several tens of degrees Celsius by a known cooling method.
Through the above steps, a modified coal M4 corresponding to low volatile steam coal having a fuel ratio of 2 to 4 is produced.

(Example)
Examples of the present invention will now be described in more detail with specific examples. However, the present invention is not limited to the following examples.
FIG. 4 is a low temperature humidity chart for air and water. The horizontal axis of FIG. 4 represents the temperature of the air, and the vertical axis represents the humidity of the air (absolute humidity, kg-water vapor / kg-dryair). The air fluidized bed dryer 18 will be described on the premise of a drying operation before the moisture content of the primary dry coal M2 reaches the limit moisture content. In air fluidized bed drying, the amount of water evaporated from coal is equal to the amount of water taken out of the system by air. Therefore, the amount of moisture taken out by air is shown using a low temperature humidity chart.

If the temperature of the external air is 25 ° C., this air is in the state of point A if the relative humidity (relative humidity) is 100%. When the air in the state of point A is heated to, for example, 70 ° C., the temperature rises while the amount of water vapor contained in the air remains constant, and the air enters the state of point B1. When the air in the state of point B1 is supplied to the air fluidized bed dryer 18 of the drying facility 10, the air is adiabatically cooled while fluidizing the high-moisture coal and is brought to the state of point C1 at about 35 ° C. and the relative humidity is 95%. Become. That is, the air at the outlet of the air fluidized bed dryer 18 is in the state of point C1. When the air state changes from the point B1 to the point C1, the water content of 0.014 (kg-water vapor / kg-dryair) corresponding to the length L1 of the vertical axis between the points B1 and C1 is high. Can be removed from coal by evaporation (water can be taken into the air).
Here, the air is assumed to have a relative humidity of 95% due to adiabatic cooling. However, the humidity is not limited to 95%, and the relative humidity is affected by the operating conditions of the dryer.

When the air in the state of point A is heated to, for example, 120 ° C., the air is in the state of point B2. When the air in the state of point B2 is supplied to the air fluidized bed dryer 18, the air is adiabatically cooled to about 42 ° C. and a relative humidity of 95% to be in the state of point C2. When the air state changes from point B2 to point C2, 0.031 (kg-water vapor / kg-dryair) of water corresponding to the length L2 of the vertical axis between point B2 and point C2 can be evaporated.
In fact, since the possibility of high moisture coal igniting increases, the air cannot be heated so far, but an example will be described for reference. When the air in the state of point A is heated to, for example, 220 ° C., which is outside the range described in FIG. 4, and the air in this state is supplied to the air fluidized bed dryer 18, the air is adiabatically cooled and the relative humidity is 95. % Point C3. In this case, 0.058 (kg-water vapor / kg-dryair) of water corresponding to the length L3 can be evaporated.

  As described above, according to the modified coal manufacturing apparatus 1 and the manufacturing method of the present embodiment, the drying step S10 includes the air fluidized bed drying step S11 and the indirect heating drying step S12. The indirect heating drying process steam generated in the indirect heating drying process S12 is used to indirectly heat the air taken from the outside in the air fluidized bed drying process S11, and the dry distillation process steam produced by exhaust heat recovery in the dry distillation process S20. Is used to indirectly heat the primary dry coal M2 in the indirect heating drying step S12. As described above, the inexpensive dry distillation process steam produced by waste heat recovery in the dry distillation process S20 is used for the indirect heating drying process S12. In the drying process S10, the indirectly heated drying process steam generated in the indirect heating drying process S12 is air. In order to use as a heat source for drying in the fluidized bed drying step S11, the high-moisture coal M1 is dried in two stages: an air fluidized bed drying step S11 and an indirect heating drying step S12.

In the present embodiment, the indirectly heated and dried process water vapor generated in the indirectly heated and dried process S12 is used for internal circulation. For this reason, the amount of steam used for internal circulation can be reduced, and the amount of water vapor required to dry the high-moisture coal M1 is 30% compared to the conventional manufacturing methods described in Patent Documents 1 and 2. Can be reduced. Thus, enormous electric power is not required for drying the high moisture coal M1, and the amount of water vapor for drying the high moisture coal M1 can be reduced.
Since the temperature inside the air fluidized bed dryer 18 is relatively low at 60 ° C. or less, the high moisture coal M1 can be dried without igniting.

The amount of water evaporated in the indirect heating drying step S12 is doubled with respect to the amount of water evaporated in the air fluidized bed drying step S11 from a certain amount of the high moisture coal M1. As a result, the total amount of indirect heat drying step water vapor obtained in the indirect heat drying step S12 is equal to the total amount of steam required for drying in the air fluidized bed drying step S11, and the thermal efficiency in this production method can be increased.
In the air fluidized bed drying step S11, the temperature of the air M5 can be more reliably increased by indirectly heating the air M5 taken from outside with the dry distillation step steam.
In the drying step S10, the air M5 taken from the outside is supplied to the air fluidized bed dryer 18, but an inert gas such as nitrogen may be used instead of the air M5.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. 4 and FIG. 5, but the same parts as those of the above-mentioned embodiment are denoted by the same reference numerals and the description thereof will be omitted, and only different points will be described. explain.
As shown in FIG. 5, the manufacturing apparatus 2 of the present embodiment includes a connection pipe 51 connected to the first water vapor supply pipe 24 and a connection pipe 51 in addition to the components of the manufacturing apparatus 1 of the first embodiment. And a heating pipe (heating pipe) 52 connected and disposed in the air fluidized bed dryer 18. The heating pipe 52 is disposed so as to be horizontal to a portion where the coal fluidized bed M6 is formed (the surface of the coal fluidized bed M6). The coal fluidized bed M <b> 6 in the air fluidized bed dryer 18 contacts the outer surface of the heating pipe 52. Indirect heating and drying process steam passing through the pipe of the first steam supply pipe 24 is supplied to the heating pipe 52 through the pipe of the connection pipe 51.
One end of the heating pipe 52 is connected to the connection pipe 51, and steam condensed water is discharged to the outside through the other end of the heating pipe 52.

The manufacturing method of this embodiment using the manufacturing apparatus 2 configured as described above will be described.
In the air fluidized bed drying step S <b> 11, the indirect heating drying step water vapor is caused to flow through the pipe line of the connection pipe 51 and the pipe line of the heating pipe 52. The inside of the coal fluidized bed M6 is indirectly heated with steam through the heating pipe 52 through an indirect heating drying process. Thereby, the high moisture coal M1 is indirectly heated not only by the air M5 taken in from the outside and heated, but also by the indirect heating drying process water vapor.

(Example)
Examples of the present invention will now be described in more detail with specific examples. However, the present invention is not limited to the following examples.
In FIG. 4, when the air in the state of point A is heated to, for example, 120 ° C., the air is in the state of point B2. When the coal fluidized bed M6 is heated by the heating pipe 52 provided in the air fluidized bed dryer 18, the ratio of heating heat and heating heat from the heating pipe 52 is 1: 1 (the length L3 in FIG. When heated to be twice the length L2, the air in the state of point B2 becomes the state of point C3 described above. For this reason, if it is a heat source having a temperature higher than the wet bulb temperature 49 ° C., which is the temperature of the intersection of the line passing through the point C3 and parallel to the vertical axis, and the horizontal axis, it can be used instead of the indirect heating drying process steam. .
In this way, when the heating heat quantity ratio from the heating air to the heating tube 52 is 1: 1, the external air is 120 ° C. outside the manufacturing apparatus 2 even if the indirect heating / drying process steam is about 110 ° C. The same effect that the water of 0.058 (kg-water vapor / kg-dryair) can evaporate is obtained, which is the same as the case where the preheating is performed up to 220 ° C.

The effect corresponding to the amount of heat by heating the coal fluidized bed M6 with the heating pipe 52 is equivalent to the amount of heat corresponding to the amount of heat from which the external air is heated from 120 ° C. to the amount of heat heated from the coal fluidized bed M6. It will be effective.
Further, the heating heat quantity ratio from the heating air to the heating pipe 52 may be other than 1: 1.

As described above, according to the modified coal manufacturing apparatus 2 and the manufacturing method of the present embodiment, the high-moisture coal M1 is dried without igniting, and the water vapor for drying the high-moisture coal M1 is inexpensive. While using waste heat recovery steam (dry distillation process steam), the amount of steam can also be reduced. Further, in the air fluidized bed drying step S <b> 11, the coal fluidized bed M <b> 6 is indirectly heated with steam through the heating pipe 52 through the indirect heating drying step. Indirect heating and drying process in addition to air M5, by indirectly heating with steam, more water is evaporated from the high moisture coal M1 while maintaining the temperature inside the air fluidized bed dryer 18 at a relatively low temperature. Can be made.
Thus, by providing the heating tube 52, the air volume required for drying can be reduced, and the manufacturing apparatus 2 can be reduced in size.

As mentioned above, although 1st Embodiment and 2nd Embodiment of this invention were explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The structure of the range which does not deviate from the summary of this invention Changes, combinations, deletions, etc. are also included. Furthermore, it goes without saying that the configurations shown in the embodiments can be used in appropriate combinations.
For example, in the first embodiment and the second embodiment, in order to further increase the temperature of the air M5 when it is supplied to the air fluidized bed dryer 18, the air M5 is made of water vapor obtained outside the manufacturing apparatus. You may heat. On the other hand, when the temperature of the air M5 supplied to the air fluidized bed dryer 18 is sufficiently high, the air M5 may not be heated with the dry distillation process steam.
When there is surplus dry distillation process steam in the production apparatus, the dry distillation process steam may flow through the conduit of the heating pipe 52.
The manufacturing apparatus may not include the air heater 17. In this case, the temperature of the drying air M5 is a maximum of 100 ° C., preferably 70 to 90 ° C.

1, 2 Production equipment (Production equipment for modified coal)
10 Drying equipment (drying section)
11 First drying equipment (first drying section)
12 Second drying equipment (second drying section)
30 Dry distillation equipment (dry distillation section)
40 Cooling equipment (cooling section)
51 Connection Piping M1 High Moisture Coal M2 Primary Dry Coal M3 Dry Coal M4 Modified Coal M5 Air M6 Coal Fluidized Bed S10 Drying Process S11 Air Fluidized Bed Drying Process S12 Indirect Heating Drying Process S20 Drying Process S30 Cooling Process

Claims (6)

A method for producing modified coal, which produces modified coal from high-moisture coal that contains 45% or more of water by mass,
A drying step of evaporating the moisture from the high moisture coal to dry coal;
A dry distillation step after the drying step to dry-distill the dry coal into the modified coal;
A cooling step for cooling the modified coal after the dry distillation step;
With
The drying step
Heating air taken from outside, fluidizing the high-moisture coal with the air to form a coal fluidized bed, and evaporating the moisture from the high-moisture coal in the coal fluidized bed to form primary dry coal A layer drying process;
After the air fluidized bed drying step, the primary dry coal is indirectly heated to evaporate the moisture from the primary dry coal into the dry coal, and the indirect heating drying step is the evaporated moisture. An indirect heating drying process for collecting water vapor;
Have
In the dry distillation step, the dry coal is carbonized, and the dry distillation step steam is recovered by exhaust heat recovery using combustion exhaust gas after supplying the dry distillation heat necessary for the dry distillation of the dry coal,
In the air fluidized bed drying step, the air taken from the outside is indirectly heated with the indirect heating drying step water vapor,
A method for producing modified coal, characterized in that the carbonization steam is used to indirectly heat the primary dry coal in the indirect heat drying step.   2. The method for producing modified coal according to claim 1, wherein in the air fluidized bed drying step, the inside of the coal fluidized bed is indirectly heated with water vapor in the indirect heating drying step.   The amount of water evaporated from the primary dry coal in the indirect heating drying step after the high moisture coal becomes the primary dry coal with respect to the amount of water evaporated from the high moisture coal in the air fluidized bed drying step. The method for producing reformed coal according to claim 1 or 2, wherein the amount is doubled.   2. The method for producing reformed coal according to claim 1, wherein in the air fluidized bed drying step, the air taken in from the outside is indirectly heated by the dry distillation step steam. An apparatus for producing modified coal that produces modified coal from high-moisture coal that contains 45% or more of water by mass,
A drying unit that evaporates the water from the high-moisture coal to form dry coal;
A carbonization section for carbonizing the dry coal into the modified coal;
A cooling section for cooling the modified coal;
With
The drying unit
The air taken in from the outside is heated, the high moisture coal is fluidized with the air to form a coal fluidized bed, and the moisture is evaporated from the high moisture coal in the coal fluidized bed to form primary dry coal. A drying section;
Indirectly heating the primary dry coal, evaporating the moisture from the primary dry coal to form the dry coal, and a second drying unit for recovering the indirectly heated drying process water vapor that is the evaporated water;
Have
In the dry distillation section, dry distillation of the dry coal, recovering the dry distillation process steam by exhaust heat recovery using combustion exhaust gas after supplying the dry distillation heat necessary for dry distillation of the dry coal,
In the first drying section, the air taken in from the outside is indirectly heated with the indirect heating drying process steam,
The apparatus for producing modified coal, wherein the dry distillation step steam is used to indirectly heat the primary dry coal in the second drying section.   6. The apparatus for producing modified coal according to claim 5, wherein in the first drying section, the inside of the coal fluidized bed is indirectly heated by the indirect heating drying step steam.

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