AU2021247761B2

AU2021247761B2 - Method and facility for manufacturing reformed coal

Info

Publication number: AU2021247761B2
Application number: AU2021247761A
Authority: AU
Inventors: Akira Kanei; Atsushi Kobayashi; Katsushi Kosuge; Hiroyuki Kozuru; Wataru Shiromizu; Wataru Tanioku
Original assignee: Nippon Steel Engineering Co Ltd
Current assignee: Nippon Steel Engineering Co Ltd
Priority date: 2020-03-30
Filing date: 2021-03-24
Publication date: 2023-11-23
Anticipated expiration: 2041-03-24
Also published as: JP7416654B2; WO2021200425A1; JP2021161144A; CN115349007A; AU2021247761A1

Abstract

Provided is a facility for manufacturing reformed coal, comprising an inner cylinder that rotates about an axis, a heating chamber that covers the inner cylinder from the radial outside of the inner cylinder, and a plurality of exhaust pipes arranged in the axial direction that penetrate through the inner cylinder in the radial direction and open into the heating chamber, coal being supplied from the end part that is positioned on the upstream side along the axial direction in the inner cylinder, and modified coal being discharged from the end part that is positioned on the downstream side along the axial direction in the inner cylinder, wherein the facility for manufacturing modified coal further comprises a temperature control unit for supplying an oxygen-containing gas to the heating chamber and controlling the temperature in the heating chamber, and a flue for discharging gas from the heating chamber, the flue being connected only to the end part that is positioned on the upstream side in the heating chamber.

Description

DESCRIPTION METHOD AND FACILITY FOR MANUFACTURING REFORMED COAL TECHNICAL FIELD

[0001] The present invention relates to a method and facility for manufacturing reformed coal. BACKGROUND ART

[0002] A method described in Patent Literature 1 has been conventionally known as a method for manufacturing reformed coal in which coal is carbonized to manufacture reformed coal. In this manufacturing method, a carbonization gas is used as a heat source for carbonization, enhancing thermal efficiency. The carbonization gas, which may be used in such a method for manufacturing reformed coal, contains tar that is a high boiling point component. Tar adhering to a pipe, for example, may block the pipe, reducing the operation rate of a carbonization facility. In view of the above, in the manufacturing method described in Patent Literature 1, the carbonization gas is mixed with a low-temperature heating gas and a waste heat gas to inhibit the adhesion of tar to pipes or the like. CITATION LIST PATENT LITERATURE(S)

[0003] Patent Literature 1: JP 2013-173831 A SUMMARY OF THE INVENTION PROBLEM(S) TO BE SOLVED BY THE INVENTION

[0004] In the above conventional method for manufacturing reformed coal, carbonization equipment for carbonizing coal is configured intricately, making the operation complicated.

[0005] The invention has been made in view of the above circumstances. An object of the invention is to simplify a configuration of carbonization equipment in a facility for manufacturing reformed coal as well as to achieve a simple operation thereof. MEANS FOR SOLVING THE PROBLEMS

[0006] In order to solve the above problems, the invention provides the following means.

[1] A facility for manufacturing reformed coal, including carbonization equipment that includes: an inner cylinder configured to rotate around an axis, into which coal is supplied from an end of the inner cylinder positioned at an upstream side in an extending direction of the axis, and from which reformed coal is discharged from an end of the inner cylinder positioned at a downstream side in the axis extending direction; a heating chamber covering the inner cylinder from an outside in a radial direction of the inner cylinder; and a plurality of connecting pipes arranged in the axis extending direction in the inner cylinder, the connecting pipes protruding beyond the inner cylinder in the radial direction and being opened in the heating chamber, in which the facility further includes: a temperature control unit configured to control a temperature inside the heating chamber by supplying an oxygen-containing gas into the heating chamber; and a flue gas duct through which gas in the heating chamber is discharged, and the flue gas duct is connected only to an end positioned at the upstream side in the axis extending direction of the heating chamber.

[2] The facility for manufacturing reformed coal according to [1], in which the temperature control unit is configured to control a temperature inside the flue gas duct and a temperature inside the heating chamber to 600 degrees C or more.

[3] The facility for manufacturing reformed coal according to [1] or [2], in which the heating chamber includes a plurality of control zones defined by zoning an inside of the heating chamber into a plurality of sections in the axis extending direction, the temperature control unit is configured to control a temperature for each of the control zones, and the flue gas duct is connected to a control zone that is included in the control zones and positioned at a most upstream side in the axis extending direction.

[4] The facility for manufacturing reformed coal according to any one of [1] to [3], further including an agitation member protruding from an inner circumferential surface of the inner cylinder toward the axis and configured to agitate the coal.

[5] The facility for manufacturing reformed coal according to [4], in which the agitation member includes a plurality of agitation members, and an agitation member included in the agitation members and disposed in a thermal decomposition zone at the downstream side in the axis extending direction of the inner cylinder is larger in an inclination angle with respect to the axis than an agitation member included in the agitation members and disposed in a moisture evaporation zone at the upstream side in the axis extending direction.

[6] The facility for manufacturing reformed coal according to [5], in which the inclination angle with respect to the axis of the agitation member disposed in the moisture evaporation zone is zero.

[7] The facility for manufacturing reformed coal according to [5] or [6], in which the agitation members are arranged in the axis extending direction within a range that accounts for more than 90% of a heating section formed by the moisture evaporation zone and the thermal decomposition zone.

[8] The facility for manufacturing reformed coal according to any one of [4] to [7], in which the agitation member and the inner circumferential surface of the inner cylinder define a gap.

[9] The facility for manufacturing reformed coal according to [8], in which a size of the gap is 10% to 25% of a dimension of the agitation member in the radial direction of the inner cylinder.

[10] The facility for manufacturing reformed coal according to any one of [4] to [8], in which the agitation member includes a bent portion inclined to the radial direction of the inner cylinder.

[11] The facility for manufacturing reformed coal according to [10], in which the bent portion is formed in a range from 30% to 70% with respect to a height of the agitation member from the inner circumferential surface of the inner cylinder, at a position close to the axis of the agitation member, and an inclination angle of the bent portion with respect to the radial direction of the inner cylinder is in a range from 10 degrees to 45 degrees.

[12] A method for manufacturing reformed coal using carbonization equipment that includes: an inner cylinder configured to rotate around an axis, into which coal is supplied from an end of the inner cylinder positioned at an upstream side in an extending direction of the axis, and from which reformed coal is discharged from an end of the inner cylinder positioned at a downstream side in the axis extending direction; a heating chamber covering the inner cylinder from an outside in a radial direction of the inner cylinder; and a plurality of connecting pipes arranged in the axial extending direction in the inner cylinder, the connecting pipes protruding beyond the inner cylinder in the radial direction and being opened in the heating chamber, the method including: controlling a temperature inside the heating chamber by supplying an oxygen-containing gas into the heating chamber; and discharging a gas present in the heating chamber, in which in the discharging of the gas, the gas is discharged only from an end positioned at the upstream side in the axis extending direction of the heating chamber.

[13] The method for manufacturing reformed coal according to [12], in which, in the controlling of the temperature, the temperature inside the heating chamber is controlled to 600 degrees C or more.

[14] The method for manufacturing reformed coal according to [12] or [13], in which the heating chamber includes a plurality of control zones defined by zoning an inside of the heating chamber into a plurality of sections in the axis extending direction, in the controlling of the temperature, the temperature is controlled for each of the control zones, and in the discharging of the gas, the gas is discharged from a control zone that is included in the control zones and positioned at a most upstream side in the axis extending direction.

[15] The method for manufacturing reformed coal according to any one of [12] to [14], further including: agitating the coal with an agitation member that protrudes from an inner circumferential surface of the inner cylinder toward the axis.

[16] The method for manufacturing reformed coal according to [15], in which the agitation member includes a plurality of agitation members, an agitation member included in the agitation members and disposed at least in a thermal decomposition zone that is included in the control zones and positioned at the downstream side in the axis extending direction of the inner cylinder has an inclination angle inclined to the axis, and the coal agitated by the agitation member having the inclination angle moves upstream in the axis extending direction.

[17] The method for manufacturing reformed coal according to [15] or [16], in which the agitation member and the inner circumferential surface of the inner cylinder define a gap, and the coal agitated by the agitation member drops through the gap.

[18] The method for manufacturing reformed coal according to any one of [15] to [17], in which the agitation member includes a bent portion inclined to the radial direction of the inner cylinder and the coal agitated by the agitation member drops from the bent portion.

[0006a] In one aspect of the present invention, there is provided a facility for manufacturing reformed coal, comprising carbonization equipment that comprises: an inner cylinder configured to rotate around an axis, into which coal is supplied from an end of the inner cylinder positioned at an upstream side in an extending direction of the axis, and from which reformed coal is discharged from an end of the inner cylinder positioned at a downstream side in the axis extending direction; a heating chamber covering the inner cylinder from an outside in a radial direction of the inner cylinder; and a plurality of connecting pipes arranged in the axis extending direction in the inner cylinder, the connecting pipes protruding beyond the inner cylinder in the radial direction and being opened in the heating chamber, wherein the facility further comprises: a temperature control unit configured to control a temperature inside the heating chamber by supplying an oxygen-containing gas into the heating chamber; and a flue gas duct through which gas in the heating chamber is discharged, and the heating chamber comprises a plurality of control zones defined by zoning an inside of the heating chamber into a plurality of sections in the axis extending direction, the temperature control unit is configured to control a temperature for each of the control zones, and the flue gas duct is connected to a control zone that is included in the control zones and positioned at a most upstream side in the axis extending direction.

[0006b] In a second aspect of the present invention, there is provided a method for manufacturing reformed coal using carbonization equipment that comprises: an inner cylinder configured to rotate around an axis, into which coal is supplied from an end of the inner cylinder positioned at an upstream side in an extending direction of the axis, and from which reformed coal is discharged from an end of the inner cylinder positioned at a downstream side in the axis extending direction; a heating chamber covering the inner cylinder from an outside in a radial direction of the inner cylinder; and a plurality of connecting pipes arranged in the axial extending direction in the inner cylinder, the connecting pipes protruding beyond the inner cylinder in the radial direction and being opened in the heating chamber, the method comprising: controlling a temperature inside the heating chamber by supplying an oxygen-containing gas into the heating chamber; and discharging a gas present in the heating chamber, wherein the heating chamber comprises a plurality of control zones defined by zoning an inside of the heating chamber into a plurality of sections in the axis extending direction, in the controlling of the temperature, the temperature is controlled for each of the control zones, and in the discharging of the gas, the gas is discharged from a control zone that is included in the control zones and positioned at a most upstream side in the axis extending direction.

[0007] According to the above configurations, the carbonization equipment in the facility for manufacturing reformed coal can be configured simply and be easy to be operated while securing the operation rate thereof. BRIEF DESCRIPTION OF DRAWING(S)

[0008] Fig. 1 is a block diagram of a facility for manufacturing reformed coal according to a first exemplary embodiment of the invention. Fig. 2 schematically shows carbonization equipment provided in the facility for manufacturing reformed coal shown in Fig. 1. Fig. 3 is a development view of an inner circumferential surface of an inner cylinder of carbonization equipment according to a second exemplary embodiment of the invention. Fig. 4A is a cross-sectional view of the inner cylinder in a non-developed state taken along a line A-A in Fig. 3. Fig. 4B is a cross-sectional view of the inner cylinder in a non-developed state taken along a line B-B in Fig. 3. Fig. 5A is a front elevational view of an agitation plate in the example of Fig. 3. Fig. 5B is a side elevational view of an agitation plate in the example of Fig. 3. Fig. 6 is a cross-sectional view of an inner cylinder of carbonization equipment according to a modification of the second exemplary embodiment of the invention. Fig. 7A is a front elevational view of an agitation plate according to a modification of the second exemplary embodiment of the invention.

5a

Fig. 7B is a side elevational view of the agitation plate according to the modification of the second exemplary embodiment of the invention. Fig. 8 is a graph showing a relationship between a temperature increase rate, a temperature, and a volatile matter content of coal in a verification test. Fig. 9 is a graph showing measurement results of overall heat transfer coefficient in a verification test. Fig. 10 is a graph showing a relationship between a size (height) of a gap, and a scattered rate and the overall heat transfer coefficient in a verification test. DESCRIPTION OF EMBODIMENT(S)

[0009] Referring to the attached drawings, preferred exemplary embodiments of the invention are described below in detail. It should be noted that components of substantially the same function(s) and structure(s) are denoted by the same reference numerals herein and in the drawings, omitting repetition of description thereof.

[0010] First Exemplary Embodiment Referring to the drawings, a facility for manufacturing reformed coal according to a first exemplary embodiment of the invention is explained below. As shown in Fig. 1, a facility for manufacturing reformed coal 10 includes a dryer 11, carbonization equipment 12, a cooler 13, and a flue gas treatment system 14. The manufacturing facility 10 is suitably usable for reforming a low rank coal with high moisture content, such as brown coal and subbituminous coal.

[0011] The dryer 11 dries coal. For example, the dryer 11 dries coal until the moisture content of coal is 15 wt% or less, preferably 10 wt% or less. The carbonization equipment 12 carbonizes dried coal. For example, the carbonization equipment 12 carbonizes coal until the temperature of coal is 500 degrees C or more, specifically in a range from 550 to 800 degrees C, thus providing reformed coal. The cooler 13 cools the reformed coal subjected to carbonization. For example, the cooler 13 cools coal until the temperature of coal is 70 degrees C or less, preferably 60 degrees C or less.

[0012] The flue gas treatment system 14 completely combusts moisture vapor discharged from the carbonization equipment 12, a carbonization gas subjected to primary combustion (i.e., partial combustion (oxidation)), and a small amount of fine powdery coal entrained with the carbonization gas, and then discharges them as flue gas to the atmosphere. The flue gas treatment system 14 includes secondary combustion equipment 15, steam generating equipment 16, a dust collector 17, an induced draft fan 18, and flue gas processing equipment 19.

[0013] The secondary combustion equipment 15 completely combusts, through secondary combustion, the carbonization gas subjected to the primary combustion. When a NOx level exceeds environmental standards in the complete combustion, NOx removal equipment is preferably provided at a subsequent stage of the secondary combustion equipment 15. The steam generating equipment 16 generates steam by recovering moisture vapor and waste heat from the carbonization gas completely combusted. The steam generating equipment 16 supplies part or the whole of the recovered steam to the dryer 11 as a heat source for drying coal. The dust collector 17 removes fly ash or the like entrained with the gas having passed through the steam generating equipment 16. The induced draft fan 18 suctions the gas from the dust collector 17 to keep pressure constant in a heating chamber of the carbonization equipment 12, and delivers the gas to the flue gas processing equipment 19. The flue gas processing equipment 19 removes SOx and the like from the gas to purify flue gas, and then discharges the flue gas to the atmosphere.

[0014] The carbonization equipment 12 is a so-called external heating rotary kiln. As shown in Fig. 2, the carbonization equipment 12 includes an inner cylinder 21, a heating chamber 22, and a temperature control unit 23.

[0015] In the carbonization equipment 12, coal passes through the inner cylinder 21 in an O-axis direction. In the inner cylinder 21, a constant amount of coal is supplied from an end at an upstream side D1 in the O-axis direction, and reformed coal is discharged from an end at a downstream side D2 in the O-axis direction. The end at the upstream side D1 of the inner cylinder 21 is connected to the dryer 11, and the end at the downstream side D2 of the inner cylinder 21 is connected to the cooler 13.

[0016] The axis 0 of the inner cylinder 21 is inclined to a horizontal direction. Specifically, the axis 0 of the inner cylinder 21 is gently inclined downward from the upstream side D1 toward the downstream side D2 in the O-axis direction. The inner cylinder 21 is rotatable around the axis 0. Since the inner cylinder 21 is inclined downward toward the downstream side and rotates around the axis 0, coal supplied from the end at the upstream side D1 of the inner cylinder 21 gradually moves toward the downstream side D2 along an inner circumferential surface of the inner cylinder 21 over a predetermined retention time.

[0017] The heating chamber 22 covers the inner cylinder 21 from the outside in a radial direction of the inner cylinder 21 (hereinafter referred to as a "radial direction"). The inner cylinder 21 is inserted into the heating chamber 22 in the O-axis direction. Both ends in the 0-axis direction of the inner cylinder 21 extend beyond the heating chamber 22 in the O-axis direction.

[0018] Connecting pipes 24 are provided for the inner cylinder 21, and a horned rotary kiln is adopted as the carbonization equipment 12. In the inner cylinder 21, the connecting pipes 24 are arranged in the O-axis direction. The connecting pipes 24, which protrude beyond the inner cylinder 21 in the radial direction, are opened in the heating chamber 22. The connecting pipes 24 are provided in a heating chamber interior portion 21a positioned in the heating chamber 22 of the inner cylinder 21. In the illustrated example, the connecting pipes 24 are provided over the whole length in the 0-axis direction of the heating chamber interior portion 21a. The connecting pipes 24 are arranged at substantially regular intervals in the 0-axis direction. Moisture vapor that is a gas generated from coal in the inner cylinder 21 and the carbonization gas that contains tar (i.e. a high boiling point component) are discharged into the heating chamber 22 through the connecting pipes 24.

[0019] The temperature control unit 23 supplies air into the heating chamber 22 to control the temperature inside the heating chamber 22. The temperature control unit 23 heats the inside of the heating chamber 22 by partially combusting (oxidizing), in air, the carbonization gas discharged into the heating chamber 22 through the connecting pipes 24, the carbonization gas containing tar (i.e. a high boiling point component). An oxygen-containing gas different from air may be supplied into the heating chamber 22 similarly to air. The oxygen-containing gas herein means a gas containing oxygen and capable of combusting (oxidizing) the carbonization gas. Flue gas containing oxygen, oxygen-enriched air, or the like may be used as the oxygen containing gas in addition to air. Further, in the exemplary embodiment, the temperature control unit 23 is configured so that the inside of the heating chamber 22 can be heated by a heat source outside the heating chamber 22, that is, a fuel gas. Natural gas, LPG gas, or the like is usable as the fuel gas, which is also used for preheating the system at the start-up thereof.

[0020] The temperature control unit 23 controls the temperature for each of control zones Z1 to Z3. The control zones Z1 to Z3 are defined by zoning the inside of the heating chamber 22 into a plurality of sections in the O-axis direction. In the illustrated example, the control zones Z1 to Z3 are defined as three sections. A first control zone Z1, a second control zone Z2, and a third control zone Z3 are arranged in this order from the upstream side D1 toward the downstream side D2.

[0021] The temperature control unit 23 includes multiple control systems 25 corresponding to the respective control zones Z1 to Z3. Each control system 25 at least includes an air supply unit 26, a heating unit 27, a temperature detecting unit 29, and a control main unit 30. In the illustrated example, in addition to the above components, a steam supply unit 28 is provided in each of the control zones Z1 to Z3. Since an oxygen-containing gas other than air may be supplied, the air supply unit 26 may be also referred to as an oxygen-containing gas supply unit.

[0022] The air supply unit 26 supplies air into the heating chamber 22. The air supply unit 26 includes an air fan 31 for supplying air to the heating chamber 22, a first pipe 32 connecting the air fan 31 to the heating chamber 22, and a first control valve 33 provided for the first pipe 32. The first pipe 32 branches into a part close to an upper wall of the heating chamber 22 and a part close to a lower wall of the heating chamber 22. The branched parts are connected to the upper wall and the lower wall of the heating chamber 22, respectively, such that the branched parts face each other. In place of the first control valve 33, a system for controlling a supply air amount, which changes the rotation rate of a motor of the air fan 31 using an inverter, is also applicable.

[0023] The heating unit 27 heats the inside of the heating chamber 22 with a fuel gas (heat source) outside the heating chamber 22. The heating unit 27 includes a burner 34 for heating the heating chamber 22, a burner air fan 36 for supplying air to the burner 34, a second pipe 37 connecting the burner air fan 36 to the burner 34, a second control valve 38 provided for the second pipe 37, a third pipe 39 through which the fuel gas is supplied to the burner 34, and a third control valve 40 provided for the third pipe 39. The burner 34 combusts the fuel gas by mixing the fuel gas with air supplied from the supply unit. The burner 34 is provided on the lower wall of the heating chamber 22 such that the burner 34 and the branched part of the first pipe 32 close to the lower wall are oriented in the same direction.

[0024] The steam supply unit 28 supplies steam into the heating chamber 22 to cool the inside of the heating chamber 22. The steam supply unit 28 supplies, for example, steam of approximately 150 degrees C into the heating chamber 22. The steam supply unit 28 includes a fourth pipe 41 through which steam is supplied into the heating chamber 22 and a fourth control valve 42 provided for the fourth pipe 41. The fourth pipe 41 is connected to the lower wall of the heating chamber 22 such that the fourth pipe 41 and the branched part of the first pipe 32 close to the lower wall are oriented in the same direction.

[0025] The temperature detecting unit 29 detects a temperature inside the heating chamber 22. The temperature detecting unit 29 may be a temperature sensor.

The control main unit 30 controls the air supply unit 26, the heating unit 27, and the steam supply unit 28 based on a detection result of the temperature detecting unit 29. In the illustrated example, the control main unit 30 controls the air supply unit 26, the heating unit 27, and the steam supply unit 28 by controlling the first to fourth control valves 33, 38, 40, and 42. The control main unit 30, which may be a controller such as a Programmable Logic Controller (PLC), may be implemented as a Distributed Control System (DCS).

[0026] The heating chamber 22 is provided with a flue gas duct 43 through which gas is discharged from the heating chamber 22. The flue gas duct 43 is connected to the heating chamber 22. The flue gas duct 43 connects the inside of the heating chamber 22 and the secondary combustion equipment 15. In this arrangement, the flue gas duct 43 is provided only at an end at the upstream side D1 of the heating chamber 22. Gas in the heating chamber 22 is thus discharged only from the end at the upstream side D1 of the heating chamber 22. The flue gas duct 43 is connected to the first control zone Z1 positioned at the most upstream side D1 among the control zones Z1 to Z3.

[0027] Subsequently, the operation of the facility for manufacturing reformed coal 10 and the carbonization equipment 12 is explained. A method for manufacturing reformed coal using the facility for manufacturing reformed coal 10 includes a drying step of drying coal, a carbonization step of carbonizing the dried coal, and a cooling step of cooling the carbonized coal. The drying step is performed by the dryer 11, the carbonization step is performed by the carbonization equipment 12, and the cooling step is performed by the cooler 13.

[0028] In the carbonization step, a preheating step for preheating the heating chamber 22 is performed first. The inside of the heating chamber 22 is heated by the heating units 27 of the temperature control unit 23. Further, coal is supplied from the end at the upstream side D1 of the inner cylinder 21 and reformed coal is discharged from the end at the downstream side D2 of the inner cylinder 21. Here, when the carbonization gas containing tar (i.e. a high boiling point component) is generated from the coal passing through the inner cylinder 21, the carbonization gas is discharged from the inner cylinder 21 into the heating chamber 22 through the connecting pipes 24.

[0029] In view of the above, temperature control for controlling the temperature inside the heating chamber 22 is performed by supplying air into the heating chamber 22 (temperature control step). The temperature inside the heating chamber 22 is increased by partially combusting (oxidizing), in air, the carbonization gas in the heating chamber 22, making it possible to heat the coal passing through the inner cylinder 21 via the inner cylinder 21. Further, the temperature inside the heating chamber 22 can be increased to such an extent that no tar adheres to wall surfaces of the heating chamber 22 and the flue gas duct 43.

[0030] In the exemplary embodiment, the temperature inside the whole heating chamber 22 is controlled to 600 degrees C or more through the temperature control for the heating chamber 22. In this situation, the temperature control unit 23 controls the temperature for each of control zones Z1 to Z3 to 600 degrees C or more. The temperature control unit 23 controls the temperature inside the heating chamber 22 to the extent that the carbonization equipment 12 is operable, without excessively increasing the temperature inside the heating chamber 22. The temperature control unit 23 can control the temperature of the heating chamber 22 by controlling only a supply amount of air from the air supply units 26. Further, the temperature control unit 23 can control the temperature of the heating chamber 22 by controlling not only the air supply units 26 but also the heating units 27 and the steam supply units 28. Furthermore, the temperature control unit 23 may perform temperature control so that the temperature inside the flue gas duct 43 is maintained at 600 degrees C or more.

[0031] The temperature inside the heating chamber 22 can be appropriately changed depending on, for example, the intended use of reformed coal to be manufactured. The temperature inside the heating chamber 22 can be set based on, for example, a reformed coal target temperature, which is a target temperature of reformed coal to be discharged from the inner cylinder 21. Specifically, the temperature inside the heating chamber 22 can be set to a temperature 100 to 150 degrees C higher than the reformed coal target temperature. It is not indispensable to make the temperature inside the heating chamber 22 100 to 150 degrees C higher than the reformed coal target temperature, and any temperature higher than the reformed coal target temperature is applicable.

[0032] For example, when the reformed coal target temperature is in a range from 650 to 850 degrees C, the volatile matter content (VM) of coal is in a range from 5 to 15 mass%. In this case, the reformed coal is provided as coal corresponding to anthracite or coal corresponding to semi-anthracite. As another example, when the reformed coal target temperature is in a range from 550 to 750 degrees C, the volatile matter content (VM) of coal is in a range from 10 to 30 mass%. In this case, the reformed coal is suitably usable as coal corresponding to thermal coal.

[0033] During the temperature control of the heating chamber 22, moisture in coal supplied from the end at the upstream side D1 to the inner cylinder 21 evaporates while the supplied coal is heated to approximately 150 degrees C. In this configuration, a large amount of heat for heating coal is required at the upstream side D1 of the inner cylinder 21, because moisture evaporation also needs heat. In contrast, a small amount of heat for heating coal is required at the downstream side D2 of the inner cylinder 21, because no moisture evaporates. Thus, the temperature of coal and the atmospheric temperature are not likely to increase at the upstream side D1 of the inner cylinder 21. Further, moisture evaporation from coal generates plenty of moisture vapor at the upstream side D1 of the inner cylinder 21. The amount of carbonization gas generated becomes larger toward the downstream side D2. The amount of carbonization gas discharged from the connecting pipes 24 into the heating chamber 22 at the downstream side D2 is thus larger than that at the upstream side D1. The same applies to the heating chamber 22. Specifically, the temperature is not likely to increase at the upstream side D1 of the heating chamber 22, because the calorie of the atmosphere gas is low at the upstream side D1.

[0034]

In view of the above, gas is discharged only from the end at the upstream side D1 of the heating chamber 22 in the exemplary embodiment (gas discharge step). Specifically, gas in the heating chamber 22 is discharged only from the flue gas duct 43 provided at the end at the upstream side D1. In this arrangement, a large amount of carbonization gas generated at the downstream side D2 of the heating chamber 22 passes the upstream side D1 of the heating chamber 22 before gas is discharged from the heating chamber 22. The temperature at the upstream side D1 of the heating chamber 22 can be reliably increased by supplying air to the carbonization gas to partially combust (oxidize) the carbonization gas.

[0035] According to the facility for manufacturing reformed coal 10, as described above, the carbonization equipment 12, the reformed coal manufacturing method, and the carbonization method of the exemplary embodiment, the temperature inside the heating chamber 22 can be increased by partially combusting (oxidizing) the carbonization gas in the heating chamber 22. The carbonization equipment 12 in the facility for manufacturing reformed coal 10 can thus be configured simply and be easy to be operated while securing the operation rate thereof by increasing the temperature inside the heating chamber 22 to an extent that no tar adheres to wall surfaces of the heating chamber 22 and the flue gas duct 43.

[0036] Further, the temperature control unit 23 controls the temperature inside the flue gas duct 43 and the temperature inside the heating chamber 22 to 600 degrees C or more. This makes it possible to reliably prevent tar from adhering to the wall surfaces of the heating chamber 22 and the flue gas duct 43. Accordingly, the operation rate of the carbonization equipment 12 in the facility for manufacturing reformed coal 10 is secured reliably.

[0037] Further, the temperature control unit 23 controls the temperature for each of the control zones Z1 to Z3. The temperature inside the heating chamber 22 can thus be reliably increased to such an extent that no tar adheres to the wall surfaces of the heating chamber 22 and the flue gas duct 43. For example, partial combustion (oxidization) of the carbonization gas is inhibited from being excessive in the third control zone Z3 at the downstream side D2 where the temperature is likely to increase. Unburnt gas in the third control zone Z3 moves upstream, and the carbonization gas containing the unburnt gas from the downstream side is partially combusted (oxidized) actively in the first control zone Z1 at the upstream side D1 where the temperature is not likely to increase. Accordingly, the operation rate of the carbonization equipment 12 in the facility for manufacturing reformed coal 10 can be secured reliably.

[0038] Various modifications of the exemplary embodiment are possible as exemplified below.

[0039] For example, steam collected by the steam generating equipment 16 is supplied to the dryer 11 as a heat source in the above example. The invention, however, is not limited thereto. The heat source may be supplied to the dryer 11 from equipment different from the steam generating equipment 16. Further, for example, the temperature control unit 23 controls the temperature for each of the control zones Z1 to Z3 in the above example. The invention, however, is not limited thereto. The temperature control unit 23 may control the temperature in the entire heating chamber 22. Furthermore, air is supplied into the heating chamber 22 in the above example. The invention, however, is not limited thereto. An oxygen-containing gas different from air may be supplied into the heating chamber 22 similarly to air. The oxygen-containing gas herein means a gas containing oxygen and capable of combusting (oxidizing) the carbonization gas. Flue gas containing oxygen, oxygen enriched air, or the like may be used as the oxygen-containing gas in addition to air. Moreover, the components in the above examples may be appropriately replaced with known components within a scope or gist of the invention. The modifications may be used in combination.

[0040] First to third verification tests for verifying the operation and effect of the first exemplary embodiment were performed. In the first to third verification tests described below, air as an oxygen-containing gas was supplied to the heating chamber 22.

[0041] First Verification Test In the first verification test, the temperature inside the heating chamber 22 was verified based on the difference in the position in the 0-axis direction of the flue gas duct 43. In the first verification test, two types of the carbonization equipment 12 were used as Test Example Al and Test Example B1. Both of the two types of carbonization equipment 12 had a diameter of the inner cylinder 21 of 500 mm, a dimension in the 0 axis direction of the heating chamber interior portion 21a of the inner cylinder 21 of 3000 mm, an inclination angle of the axis 0 of the inner cylinder 21 with respect to a horizontal direction of 1.0 degree, and a rotation rate of the inner cylinder 21 of 3.1 rpm. Moisture of coal supplied to the inner cylinder 21 was 11.8 wt%, and the supply rate of coal supplied to the inner cylinder 21 was in a range from 280 to 290 kg/h. Further, the supply rate of the air amount from each of the control systems 25 to the corresponding one of the control zones Z1 to Z3 was set based on the temperature of the second control zone Z2. In this setting, the supply rates of the air amounts from the control systems 25 to the respective control zones Z1 to Z3 were equivalent, and the supply rate of the total of the air amounts in the three zones was in a range from 280 to 285 Nm 3 /h.

[0042] Test Example Al was made different from Test Example B1 in the position in the -axis direction of the flue gas duct 43. In Test Example Al, similar to the above exemplary embodiment, the flue gas duct 43 was connected only to the control zone Z1 at the end on the upstream side D1 of the heating chamber 22. In Test Example B1, the flue gas duct 43 was connected only to the control zone Z3 at the end on the downstream side D2 of the heating chamber 22. In the first verification test, a temperature in each of the first to third control zones Z1 to Z3 and a temperature of discharged coal, which was a temperature of coal discharged from the inner cylinder 21, were measured. Table 1 shows the results.

[0043]

[Table 1]

Temperature Temperature Temperature Temperature (°C) in first (°C) in second (°C) in third (°C) of control zone control zone control zone discharged coal

Test Example 797 829 836 660 All Test Example 779 822 831 651 B1

[0044] It is verified from the result that variation in the temperature inside the heating chamber 22 in Test Example Al was smaller than that in Test Example B1, and the temperature of discharged coal in Test Example Al was higher than that in Test Example B1.

[0045] Second Verification Test In the second verification test, the adhesion of tar was verified based on the difference in the temperature inside the heating chamber 22. In the second verification test, two types of the carbonization equipment 12 were used as Test Example A2 and Test Example B2. Both of the two types of carbonization equipment 12 had a diameter of the inner cylinder 21 of 500 mm, a dimension in the O-axis direction of the heating chamber interior portion 21a of the inner cylinder 21 of 3000 mm, an inclination angle of the axis 0 of the inner cylinder 21 with respect to a horizontal direction of 1.0 degree, and a rotation rate of the inner cylinder 21 of 3.1 rpm. Moisture of coal supplied to the inner cylinder 21 was 12.3 wt%, and the supply rate of coal supplied to the inner cylinder 21 was in a range from 275 to 280 kg/h. Further, the flue gas duct 43 was connected only to the control zone Z1 at the end on the upstream side D1 of the heating chamber 22.

[0046] For the purpose of comparing the effects of tar adhesion based on the operation temperature of the heating chamber 22, Test Example A2 was made different from Test Example B2 in the target temperature of the second control zone Z2. The temperature of the second control zone Z2 was approximately 630 degrees C in Test Example A2. The temperature of the second control zone Z2 was approximately 550 degrees C in Test Example B2. In Test Examples A2 and B2, the supply rate of the air amount from each of the control systems 25 to the corresponding one of the control zones Z1 to Z3 was set based on the target temperature of the second control zone Z2. In Test Examples A2 and B2, the supply rates of the air amounts from the control systems 25 to the respective control zones Z1 to Z3 were equivalent. Specifically, the supply rate of the total of the air amounts in the control zones Z1 to Z3 was 215 Nm 3/h in Test Example A2, and the total of the supply rate of the total of the air amounts in the control zones Z1 to Z3 was 163 Nm 3/h in Test Example B2. Then, a temperature in each of the first to third control zones Z3 and a temperature of discharged coal were measured in Test Examples A2 and B2. Table 2 shows the results.

[0047]

[Table 2]

Temperature Temperature Temperature Temperature (°C) in first (°C) in second (0C) in third (°C) of control zone control zone control zone discharged coal Test Example 576 631 649 535 A2 Test Example 496 557 576 451 B2

[0048] In the second verification test, Test Examples A2 and B2 lasted for five consecutive days. A pressure loss between the inner cylinder 21 and the secondary combustion equipment 15 for the first day and a pressure loss between the inner cylinder 21 and the secondary combustion equipment 15 for the fifth day were each measured. The pressure loss between the inner cylinder 21 and the secondary combustion equipment 15 was measured by the pressure difference of gas between the end at the downstream side D2 of the inner cylinder 21 and the end at the secondary combustion equipment 15 side.

[0049] In both Test Examples A2 and B2, the pressure loss of the flue gas duct 43 immediately after the start of operation was 0.02 kPa on the first day. In Test Example

A2, the pressure loss of the flue gas duct 43 was 0.03 kPa on the fifth day. In Test Example B2, the pressure loss of the flue gas duct 43 was 1.45 kPa on the fifth day. It is verified from the result that the pressure loss of the flue gas duct 43 in Test Example A2 was smaller than that in Test Example B2, and the adhesion of tar was inhibited in Test Example A2.

[0050] Third Verification Test In the third verification test, the difference in volatile matter content of coal caused by controlling the temperature for each of the control zones Z1 to Z3 was verified. In the third verification test, two types of the carbonization equipment 12 were used as Test Example A3 and Test Example B3. Both of the two types of carbonization equipment 12 had a diameter of the inner cylinder 21 of 500 mm, a dimension in the 0 axis direction of the heating chamber interior portion 21a of the inner cylinder 21 of 3000 mm, an inclination angle of the axis 0 of the inner cylinder 21 with respect to a horizontal direction of 1.0 degree, and a rotation rate of the inner cylinder 21 of 3.1 rpm. Moisture of coal supplied to the inner cylinder 21 was 12.1 wt%, and the supply rate of coal supplied to the inner cylinder 21 was in a range from 220 to 225 kg/h. Further, the flue gas duct 43 was connected only to the control zone Z1 at the end on the upstream side D1 of the heating chamber 22. The air supply rate from each of the control systems 25 to the corresponding one of the control zones Z1 to Z3 was set based on the temperature of reformed coal discharged from the inner cylinder 21. Each control system 25 was controlled so that the temperature of discharged coal was about 655 degrees C.

[0051] Test Example A3 was made different from Test Example B3 in the temperature distribution in the heating chamber 22. Specifically, in Test Example A3, the temperature of the heating chamber 22 was controlled by the temperature control unit 23 so that the temperatures in the control zones Z1 to Z3 were almost equivalent (see, Table 3). In Test Example A3, the supply rates of the air amounts from the respective control systems 25 were made different from each other. Air was supplied to the first control zone Z1 at 120 Nm 3 /h, to the second control zone Z2 at 70 Nm 3/h, and to the third control zone Z3 at 35

Nm 3/h. In Test Example B3, the air supply rates from the respective control systems 25 were equivalent, and air was supplied to the respective control zones Z1 to Z3 at an air-amount supply rate of 75Nm 3/h. As a result, the temperatures in the control zones Z1 to Z3 were different from each other in Test Example B3 as shown in Table 3.

[0052]

[Table 3]

Temperature Temperature Temperature (0C) in first (°C) in second (0C) in third control zone control zone control zone Test Example 827 824 A3 830

Test Example 791 819 B3 841

[0053] In the third verification test, the volatile matter content of reformed coal discharged from the inner cylinder 21 was measured for each of Test Example A3 and Test Example B3. In Test Example A3, the volatile matter content was 6.2 wt%. In Test Example B3, the volatile matter content was 9.2 wt%. It is verified from the result that, although the temperature of discharged coal of Test Example A3 was equivalent to that of Test Example B3, the volatile matter content of Test Example A3 was smaller than that of Test Example B3. Carbonization in Test Example A3 was thus effective.

[0054] Second Exemplary Embodiment Subsequently, a second exemplary embodiment of the invention is explained. Also in the second exemplary embodiment, reformed coal is manufactured by a manufacturing facility including carbonization equipment, which is an external heating rotary kiln similar to the first exemplary embodiment. In the second exemplary embodiment, an agitation member for agitating coal is provided in an inner cylinder of the carbonization equipment, as described below. Except for the above, a configuration of a general-purpose external heating rotary kiln may be employed without being limited to the example of the first exemplary embodiment. For example, it is not indispensable to connect a flue gas duct only to an end at an upstream side of a heating chamber.

[0055] Fig. 3 is a development view of an inner circumferential surface of the inner cylinder of the carbonization equipment according to the second exemplary embodiment of the invention. In the illustrated example, the inside of the inner cylinder 21 is zoned as a feeding section 211 and a heating section 212, which are arranged from the upstream side to the downstream side in this order. The heating section 212 is further zoned as a moisture evaporation zone 212A and a thermal decomposition zone 212B. A discharge section 213 is provided at the downstream side of the thermal decomposition zone 212B. In the moisture evaporation zone 212A and the thermal decomposition zone 212B of the exemplary embodiment, agitation plates 51 and 52 for agitating coal protrude from an inner circumferential surface 21c of the inner cylinder 21 toward the axis O (see Fig. 2). A feeding lifter 211L for feeding coal to the heating section 212 is provided in the feeding section 211. The agitation plates and lifter are not provided in the discharge section 213.

[0056] Irrespective of the connecting pipes 24 arranged at different positions at intervals of 90 degrees in a circumferential direction of the inner cylinder 21, the agitation plates 51 and 52 are arranged at predetermined intervals (at intervals of 45 degrees in the illustrated example) in the circumferential direction of the inner cylinder 21. In the moisture evaporation zone 212A, the agitation plates 51 arranged in the circumferential direction each extend parallel to the axis 0. That is, an inclination angle of the agitation plates 51 with respect to the axis 0 in the moisture evaporation zone 212A is zero. Fig. 4A is a cross-sectional view taken along a line A-A of Fig. 3, that is, a cross-sectional view of the inner cylinder 21 not developed in the moisture evaporation zone 212A. The agitation plates 51 protrude from the inner circumferential surface 21c of the inner cylinder 21 toward the axis 0. The agitation plates 51 are arranged at regular intervals in the circumferential direction of the inner cylinder 21. An end at an opposite side of each agitation plate 51 from the axis 0 is connected with the inner circumferential surface 21c via a bracket 53. The adjacent ones of the agitation plate 51 arranged in the O-axis direction are shifted from each other by half of its interval (22.5 degrees in the illustrated example) in the circumferential direction of the inner cylinder 21. In the moisture evaporation zone 212A of the second exemplary embodiment, for example, four rows of the agitation plates 51 are arranged in the O-axis direction.

[0057] In the thermal decomposition zone 212B, the agitation plates 52 are arranged at intervals in the circumferential direction and the longitudinal direction that are similar to those of the agitation plates 51 in the moisture evaporation zone 212A. In the illustrated example, the agitation plates 52 are arranged at intervals of 45 degrees in the circumferential direction. In the thermal decomposition zone 212B, the agitation plates 52 arranged in the circumferential direction each have an inclination angle P with respect to the axis 0 (see Fig. 3). The inclination angle P is, for example, approximately 4.3 to 4.5 degrees. Since the agitation plates 52 in the thermal decomposition zone 212B have an inclination angle P, coal passing through the inner cylinder 21 rotating in a predetermined direction can be agitated to move upstream in the inner cylinder 21. On the other hand, in the moisture evaporation zone 212A, coal is fed toward the thermal decomposition zone 212B by the agitation plates 51 with no inclination angle. The coal is thus charged more uniformly in the thermal decomposition zone 212B, lengthening a retention time of coal in the thermal decomposition zone 212B. Fig. 4B is a cross-sectional view taken along a line B-B of Fig. 3, that is, a cross-sectional view of the inner cylinder 21 not developed in the thermal decomposition zone 212B. The agitation plates 52 protrude from the inner circumferential surface 21c of the inner cylinder 21 toward the axis 0. The agitation plates 52 are arranged at regular intervals in the circumferential direction of the inner cylinder 21. Since each agitation plate 52 has an inclination angle P with respect to the axis 0, not only an end surface but also a plate surface is shown in the example of Fig. 4B. In the thermal decomposition zone 212B of the second exemplary embodiment, for example, eight rows of the agitation plates 52 are arranged in the O-axis direction.

[0058]

As shown in Figs. 5A and 5B, the agitation plate 52 in the thermal decomposition zone 212B is connected with the inner circumferential surface 21c via the brackets 53, with a gap 54 interposed between the agitation plate 52 and the inner circumferential surface 21c of the inner cylinder 21. The gap 54 allows a part of coal agitated by the agitation plate 52 during rotation of the inner cylinder 21 to drop toward the inner circumferential surface 21C. This makes it possible to mix coal in the inner cylinder 21 while inhibiting coal particles from being scattered toward the 0-axis and being sucked from the connecting pipe 24.

[0059] In the exemplary embodiment, the agitation plates 51 and 52 are arranged over the entirety of the heating section 212 in the0-axis direction, the heating section 212 including the moisture evaporation zone 212A and the thermal decomposition zone 212B. In order to uniformly agitate and mix coal while inhibiting scattering thereof, the agitation plates 51 and 52 are preferably provided in a range that accounts for more than 90% of the heating section 212.

[0060] Referring back to Fig. 1, which is used for explaining the first exemplary embodiment, a method for manufacturing reformed coal using the carbonization equipment according to the second exemplary embodiment is explained below. First, the inner cylinder 21 is rotated around the axis 0 by a driving unit (not shown) and the inside of the heating chamber 22 is heated by the heating unit(s) 27. When the inside of the inner cylinder 21 is heated to a predetermined high temperature, coal is fed into the inner cylinder 21 and carbonized by high heat of the heating chamber 22.

[0061] Coal fed into the rotating inner cylinder 21 is delivered to the moisture evaporation zone 212A of the heating section 212 by the lifter 211L provided in the feeding section 211. Moisture in the coal evaporates in the moisture evaporation zone 212A. In the moisture evaporation zone 212A, the agitation plates 51 are arranged in parallel with the axis 0 of the inner cylinder 21. Coal particles are thus delivered along the inner circumferential surface 21c of the inner cylinder 21 while being agitated by the agitation plates 51, and fed to the thermal decomposition zone 212B.

[0062]

In the thermal decomposition zone 212B, the agitation plates 52 rotate together with the rotation of the inner cylinder 21, so that coal is agitated and mixed by the agitation plates 52 in the inner cylinder 21. In the situation, a part of coal is lifted by the agitation plates 52, and the remaining part not lifted by the agitation plates 52 drops on the inner circumferential surface 21c through the gaps 54 and moves on the inner circumferential surface 21c. Since not all of the coal on the agitation plates 52 drop toward the O-axis, the scattered amount of coal due to agitation can be reduced.

[0063] As shown in Fig. 4B, the agitation plates 52 arranged in the thermal decomposition zone 212B preferably have a height ha (dimension from the inner circumferential surface 21c in a radial direction of the inner cylinder 21) that is 60 to 90% of a height hm of charged coal. When the height hm of charged coal is too lower than the height ha of the agitation plate 52, the effect of agitation is small. When the height hm of charged coal is too higher than the height ha of the agitation plate 52, a large amount of coal is scattered. The amount of coal to be fed into the inner cylinder 21 may be adjusted so that the height ha of the agitation plates 52 relative to the height hm of charged coal falls within the above range. As shown in Fig. 5A, it is assumed that a distance from an intersection of the inner circumferential surface 21c with an extension plane of the agitation plate 52 (a position at which the bracket 53 is joined to the inner circumferential surface 21c) to an end close to the O-axis of the agitation plate 52 is defined as a height ha, and a height of the gap 54 (a distance from the intersection of the inner circumferential surface 21c with the extension plane of the agitation plate 52 to an end close to the inner circumferential surface 21c of the agitation plate 52) is defined as a height hb, the height hb of the gap 54 is preferably 10 to 25%, more preferably 10 to 20% of the height ha of the agitation plate 52.

[0064] As described above, in the second exemplary embodiment, when coal is carbonized in the thermal decomposition zone 212B of the inner cylinder 21, coal is agitated using the agitation plates 52 to inhibit the melt-adhesion or agglomeration of coal. This reduces temperature deviation of coal deposited inside the inner cylinder

21, resulting in efficient heat transmission from the heating chamber 22. Further, since the gaps 54 inhibit coal from being scattered during agitation, particles of carbide (i.e. a nonvolatile component) are inhibited from being discharged from the connecting pipes 24.

[0065] Further, since the axis 0 of the inner cylinder 21 is gently inclined as described above, coal moves downstream throughout the inner cylinder 21. In the thermal decomposition zone 212B, however, the agitation plates 52 have an inclination angle P. This inhibits, to a certain extent, coal agitated by the agitation plates 52 from moving downstream, and a part of coal is made to move upstream. In the moisture evaporation zone 212A, coal is fed out toward the downstream side by the agitation plates 51 with no inclination angle. The coal is thus charged more uniformly in the thermal decomposition zone 212B, lengthening a retention time of coal in the thermal decomposition zone 212B. Consider a case, different from the exemplary embodiment, where the thermal decomposition zone 212B including agitation plates with no inclination angle has a temperature of 650 degrees C. In this case, a time during which coal fed to the inner cylinder 21 stays in the thermal decomposition zone 212B is approximately 50 minutes. When the agitation plates 52 having an inclination angle P are provided in the thermal decomposition zone 212B as in the exemplary embodiment without changing other conditions, a time during which coal stays in the thermal decomposition zone 212B is extended by approximately 20% to about 60 minutes. A heat receiving area of coal is thus increased by approximately 8%. That is, in this example, the heat-transfer efficiency to coal in carbonization equipment is improved by approximately 8% by providing the agitation plates 52 with an inclination angle.

[0066] The second exemplary embodiment can be combined with the first exemplary embodiment. Further, various modifications can be added to the second exemplary embodiment as exemplified below. The arrangement where the agitation plates 52 having an inclination angle P are provided and the arrangement where the gap 54 is provided between the agitation plates 52 and the inner circumferential surface 21c of the inner cylinder 21 have mutually different effects, and any one of the arrangements may be employed.

[0067] For example, in the above example, the agitation plates 51 are arranged in parallel with the axis 0 in the moisture evaporation zone 212A. The invention, however, is not limited thereto. The agitation plates 51 having an inclination angle with respect to the axis 0 may be arranged in the moisture evaporation zone 212A. In this case, the inclination angle of the agitation plates 51 with respect to the axis 0 is preferably smaller than an inclination angle P of the agitation plates 52.

[0068] The agitation plates 52 are preferably arranged at regular intervals in the circumferential direction of the inner cylinder 21. The invention, however, is not limited thereto. The agitation plates 52 may be arranged at unequal intervals. Four to twelve agitation plates 52, preferably, six to ten agitation plates 52, may be provided according to the inner diameter of the inner cylinder 21. The number of agitation plates 52 arranged in the circumferential direction of the inner circumferential surface 21c can be determined as appropriate, as long as the agitation plates 52 effectively agitate and mix coal to provide the favorable effect. However, too many agitation plates 52 are unfavorable, because the thermal decomposition zone 212B excessively divided into many segments inhibits coal particles from being mixed uniformly.

[0069] Referring to Figs. 6, 7A, and 7B, a modification of the second exemplary embodiment of the invention is explained. In this modification, the agitation plate 52 has a bent portion 52b inclined to the radial direction of the inner cylinder 21. Specifically, as shown in Fig. 7A, it is assumed that: a distance from an intersection of the inner circumferential surface 21c with an extension plane of the agitation plate 52 (a position at which the bracket 53 is joined to the inner circumferential surface 21c) to an end close to the O-axis of the agitation plate 52 is defined as a height ha; a height of the gap 54 (a distance from the intersection of the inner circumferential surface 21c with the extension plane of the agitation plate 52 to an end close to the inner circumferential surface 21c of the agitation plate 52) is defined as a height hb; and a distance from the inner circumferential surface 21c to a boundary between the bent portion 52b formed at the 0-axis side of the agitation plate 52 and a remaining part of the agitation plate 52 is defined as a height hc. In this case, the height hc is preferably 30% to 70% of the height ha. That is, the bent portion 52b is preferably formed, at the 0-axis side of the agitation plate 52, in a range from 30% to 70% of a height of the agitation plate 52 from the inner circumferential surface 21c of the inner cylinder 21. Further, an inclination angle y of the bent portion 52b with respect to the radial direction of the inner cylinder 21 is preferably in a range from 10 degrees to 45 degrees. In this modification, coal that is agitated by the agitation plate 52 and rests on the bent portion 52b drops first. This reduces the scattering of coal compared to a case where coal drops at once from an end of the agitation plate 52 at which no bent portion is provided (when the angle of the agitation plate 52 exceeds a horizontal angle due to rotation of the inner cylinder 21).

[0070] Fourth Verification Test Subsequently, verification test results according to the second exemplary embodiment of the invention are explained. In Test Examples A4 and A5 of a fourth verification test, lignite of which volatile matter content was approximately 50 wt% was crashed into pieces of 5 mm or less and dried. This was used as coal material to perform a pyrolysis test. Fig. 8 is a graph showing a relationship between the heating temperature of coal material and the VM value (volatile matter content) of reformed coal produced. The temperature increase rate of coal was 7 degrees C/min in Test Example A4, and 25 degrees C/min in Test Example A5. The respective rates were kept for one minute. In each of Test Examples A4 and A5, the VM value was measured where the coal temperature was 550 degrees C, 650 degrees C, and 750 degrees C. As a result, the VM value of Test Example A4, of which temperature increase rate was lower than that of Test Example A5, was lower than the VM value of Test Example A5. It is understood from the result that, even when there is no difference in final reaching temperature of coal, the VM value of coal can be decreased to accelerate volatilization of carbonized coal by setting the temperature increase rate at a relatively low rate to keep the heating time (retention time) of coal in the thermal decomposition zone long.

[0071]

Fifth Verification Test In a fifth verification test, coal was carbonized using an external heating rotary kiln, as follows: an inner diameter of an inner cylinder ((p) of 500 mm, and a heating length (L) of 3000 mm (a length of a heating section including the moisture evaporation zone and the thermal decomposition zone). Four agitation plates were placed in a circumferential direction of an inner surface of the inner cylinder over an entire length of the heating section. Then, the test was conducted in a case where the inclination angle of the agitation plates was 0.0 degrees (Test Example B4), a case where the inclination angle of the agitation plates was 4.0 degrees (Test Example A6), and a case where the inclination angle of the agitation plates was 6.0 degrees (Test Example A7). The conditions for the test were as follows: a coal feeding amount of 280 kg/h; a rotation rate of the inner cylinder of 3.1 rpm; a downward inclination angle of the inner cylinder of 1.0 degree; a height of the agitation plate (ha) of 90 mm. Under the above conditions, a measured retention time (min) and an overall heat transfer coefficient (kcal / m 2 hOC) were measured in the test. The results are shown in Table 4.

[0072]

[Table 4]

Inclination angle Measured Overall heat of agitation plate retention time transfer coefficient (deg) (min) (kcal/m 2h°C) Test Example 0.0 26.2 B4 51.9 Test Example 4.0 30.4 54.5 A6 Test Example 6.0 32.6 A7 55.7

[0073] It is verified from the test results shown in Table 4 that the measured retention time of Test Examples A6 and A7, in which the agitation plates arranged in the heating section of the inner cylinder had an inclination angle, was longer than the measured retention time of Test Example B4 in which the agitation plates had no inclination angle, and that the overall heat transfer coefficient of Test Examples A6 and A7 was larger than that of Test Example B4.

[0074] Sixth Verification Test In a sixth verification test, coal was carbonized using an external heating rotary kiln, as follows: an inner diameter of an inner cylinder ((p) of 500 mm, a heating length (L) of 3000 mm, and a downward inclination angle of the inner cylinder of 1.0 degree. In the heating section of Test Example B5, the agitation plates having no inclination angle with respect to an axis were placed over its entire length. In the heating section of Test Example A8, the agitation plates having no inclination angle were placed in a range of 600 mm from an upstream end of the inner cylinder, and the agitation plates having an inclination angle of 4 degrees were placed in a range more distant from the upstream end than the above range. In the heating section of Test Example A9, the agitation plates having no inclination angle were placed in a range of 600 mm from the upstream end of the inner cylinder, and the agitation plates having an inclination angle of 6 degrees were placed in a range more distant from the upstream end than the above range. The conditions for the test were as follows: a coal feeding amount of 280 kg/h; a rotation rate of the inner cylinder of 3.1 rpm; a height (ha) of the agitation plate of 90 mm; a target temperature of carbide at a downstream end of the inner cylinder of 640 degrees C. The measured retention time (min), the overall heat transfer coefficient (kcal/m2h°C), and the volatile matter content (%) after carbonization were measured in Test Examples B5, A8, and A9. The results are shown in Table 5.

[0075]

[Table 5]

Inclination angle Measured Overall heat Volatile matter of agitation plate retention time transfer coefficient content of (min) (kcal/m2h°C) carbond coal (deg) Test Example 0.0 26.2 51.9 11.6 B5 Test Example 4.0 29.9 53.6 10.6 A8 Test Example 6.0 31.8 56.1 9.8 A9

[0076]

It is verified from the test results shown in Table 5 that the measured retention time, mainly in the moisture evaporation zone, of Test Examples A8 and A9 was slightly shorter than that of Test Examples A6 and A7, Test Examples A8 and A9 being an example where the agitation plates having no inclination angle were placed in the moisture evaporation zone and the agitation plates having an inclination angle were placed in the thermal decomposition zone, Test Examples A6 and A7 being an example where the agitation plates having an inclination angle were placed over an entire length of the heating section. Note that, in the moisture evaporation zone, a temperature difference between the inside and the outside of the inner cylinder is large, because moisture contained in coal is not yet completely evaporated. The overall heat transfer coefficient is thus not increased with a longer retention time. For the above reason, there was no substantial difference in overall heat transfer coefficient between Test Examples A6, A7 and Test Examples A8, A9 having the almost the same retention time in the thermal decomposition zone. When the target temperature of carbide at the downstream end of the inner cylinder was the same in Test Examples A6, A7, A8, and A9, reformed coal having a lower volatile matter content was obtained in Test Examples A6 and A7 having a longer measured retention time.

[0077] Seventh Verification Test In a seventh verification test, coal was carbonized using an external heating rotary kiln, as follows: an inner diameter of an inner cylinder ((p) of 500 mm, a heating length (L) of 3000 mm, and a downward inclination angle of the inner cylinder of 1.0 degree. Then, the test was conducted about a measured value of overall heat transfer coefficient inside the inner cylinder by changing the conditions (e.g., the absence or presence of agitation plate(s) and the number of agitation plates). The conditions for the test were as follows: a coal feeding amount of 190 to 280 kg/h; a rotation rate of the inner cylinder of 2.2 to 3.0 rpm; a combustion temperature in the heating chamber of 790 to 840 degrees C; a height (hm) of coal charged in the inner cylinder of 100 to 140 mm. In Test Example B6, no agitation plates were provided. In Test Example A10, two agitation plates were placed in a circumferential direction (at intervals of 180 degrees). In Test Example All, four agitation plates were placed in the circumferential direction (at intervals of 90 degrees). In Test Example A12, eight agitation plates were placed in the circumferential direction (at intervals of 45 degrees). All the agitation plates had a height (ha) of 75 mm. Coal was carbonized while changing the length over which the agitation plates were placed and changing a value K obtained by dividing a value, which was obtained by multiplying the number of agitation plates in the circumferential direction by an entire length of the agitation plates, by a heating length L. The overall heat transfer coefficient U (kcal/m 2h°C) was measured for a dimension of an entire inner circumferential surface of the inner cylinder.

[0078] Fig. 9 is a graph showing measurement results of overall heat transfer coefficient according to the seventh verification test. As shown in the graph, it is verified that the overall heat transfer coefficient was increased by providing the agitation plates and increasing the number and total area in the circumferential direction of the agitation plates. This measurement results show that the agitation and mixing of coal is facilitated in the inner cylinder by providing the agitation plates and increasing the number and total area in the circumferential direction of the agitation plates.

[0079] Eighth Verification Test In an eighth verification test, a difference in the scattered position of coal according to the presence or absence of the bent portion of the agitation plate in an external heating rotary kiln (an inner diameter of an inner cylinder ((p) of 2700 mm, a heating length (L) of 3000 mm) was calculated by Discrete Element Method (DEM). The rotation rate of the inner cylinder was 2.7 rpm and a height (hm) of simulated particles of coal charged in the inner cylinder was 690 mm. In Test Examples B7 and Al3, six agitation plates were placed in the circumferential direction at intervals of 60 degrees. Each agitation plate in Test Example B7 had a flat plate shape extending radially in the inner cylinder. Each agitation plate in Test Example A13 had a bent portion at an upper portion of the agitation plate as shown in Fig. 6. In Test Examples B7 and Al3, no gap was formed between the agitation plates and the inner circumferential surface of the inner cylinder. In Test Examples B7 and A13, a scattered amount of particles of coal agitated by the agitation plates while the inner cylinder rotates three times was calculated as a function of distance from a center axis of the inner cylinder to the inner circumferential surface. The results are shown in Table 6.

[0080]

[Table 6]

TestExampleB7 TestExampleA13 Distance from axis (mm) The number of The number of particles particles (pieces) (pieces) 0 Axis 0 0 Outer circumference of inlet of connecting 250 pipe 20,100 0 670 59,850 21,500 920 48,620 59,200 1,140 0 1,210 Inner circumferential surface of inner 1,3501cylinder 0 0

[0081] It is revealed from the results of Table 6 that the scattered range of coal particles in Test Example A13 was closer to the inner circumferential surface than to the axis, compared to Test Example B7. The results show that coal particles scattered in the vicinity of the axis of the inner cylinder and discharged through the connecting pipes can be reduced by providing the bent portions of the agitation plates.

[0082] Ninth Verification Test In a ninth verification test, coal was carbonized using an external heating rotary kiln (an inner diameter of an inner cylinder (<p) of 500 mm, a heating length (L) of 3000 mm). Then, the test was conducted about a difference in the scatter state of coal according to the presence or absence of a gap between the agitation plates and the inner circumferential surface of the inner cylinder. In each Example, the height ha of the agitation plates from the inner circumferential surface of the inner cylinder to the upper end was 90 mm. The agitation plates each had a bent portion at an upper portion thereof. A size (height) of the gap between the agitation plates and the inner circumferential surface was zero (no gap) in Test Example B8, a height of 15 mm in Test Example A14, and a height of 35 mm in Test Example B9. The moisture content of coal fed into the inner cylinder was 12.50% and the rotation rate of the inner cylinder was 3.1 rpm. In the test, a predictive value of a discharge amount of reformed coal after carbonization was calculated using a known yield function on a basis of the fed amount of coal and the temperature after heating. A scattered rate was calculated by regarding a difference between the above predictive value and an actually measured value of discharge amount of reformed coal discharged from the inner cylinder, as an amount of particles of coal scattered in the inner cylinder and discharged from the connecting pipes. The results are shown in Table 7.

[0083]

[Table 7]

Actually Gap Fed amount of Predictive value measured value Scattered (MM) coal of discharge of discharge rate (kg/h) amount (kg/h) amount (%) (kg/h) Test Example B8 0 260 131.6 115.8 12.0 Test Example A14 15 235 121.1 113.4 6.4 Test Example B9 35 280 143.0 136.7 4.4

[0084] It is revealed from the results of Table 7 that the scattered amount of coal can be reduced by increasing the gap between the agitation plates and the inner circumferential surface of the inner cylinder. However, as shown by a verification test described below, the height of the gap is preferably set in an appropriate range. This is because too large gap may decrease the coefficient of heat transfer to coal.

[0085] Tenth Verification Test In a Tenth verification test, coal was carbonized using an external heating rotary kiln (an inner diameter of an inner cylinder (<p) of 500 mm, a heating length (L) of 3000 mm). Then, the overall heat transfer coefficients were measured in a case where the gap between the agitation plates and the inner circumferential surface of the inner cylinder was provided and a case where no gap therebetween was provided. In each Example, the height ha of the agitation plates from the inner circumferential surface of the inner cylinder to the upper end was 90 mm, and the gap between the inner circumferential surface and the agitation plates was zero (no gap) in Test Example B10, a height of 15 mm in Test Example Al5, and a height of 35 mm in Test Example B11. The rotation rate of the inner cylinder was 2.7 rpm, the fed amount of coal was 280 kg/h, and the height (hm) of coal charged in the inner cylinder was 150 mm. Table 8 shows calculation results of the overall heat transfer coefficient in respective Examples.

[0086]

[Table 8]

Overall heat Gap transfer (mm) coefficient (kcal/m 2h°C) Test Example 0 50.8 B10 Test Example 15 57.8 A15 Test Example 35 47.6 B11

[0087] It is revealed from the results of Table 8 that the overall heat transfer coefficient of Test Example A15, in which the gap had a height of 15 mm, was higher than that of Test Example B10 in which no gap was provided, but the overall heat transfer coefficient of Test Example B11, in which the gap had a height of 35 mm, was lower than that of Test Example B10 in which no gap was provided. It is understood from the results that the coal agitation efficiency was improved by providing an appropriate gap between the agitation plates and the inner circumferential surface of the inner cylinder, and too large gap reduced the agitation efficiency.

[0088]

Fig. 10 is a graph showing a relationship between the height of the gap from the inner circumferential surface of the inner cylinder to the agitation plates, and the scattered rate of coal and the overall heat transfer coefficient in the ninth and tenth verification test results. As shown in the graph, the scattered rate of coal particles was smaller as the gap was larger. The heat transfer coefficient was maximum when the gap had a predetermined value (15 mm in this Example), and too large gap decreased the heat transfer coefficient. For example, assuming that a range of the overall heat transfer coefficient exceeding 10 kcal/m2 h°C is appropriate in the graph, it can be said that the height of the gap is preferably 9 to 23 mm, that is, preferably in a range of 10 to 25%, more preferably in a range of 10 to 20% of the height ha of the agitation plates.

[0089] Preferred exemplary embodiments of the invention have been described in detail with reference to attached drawings. However, the scope of the invention is not limited to the above exemplary embodiments. It would be obvious for those skilled in the art to which the invention pertains that various modifications and revisions are conceivable within the technical idea recited in claims, and it is understood that such modifications and revisions are naturally within the technical scope of the invention.

[0090] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. EXPLANATION OF CODES

[0091] 10...manufacturing facility, 11...dryer, 12...carbonization equipment, 13...cooler, 14... flue gas treatment system, 15...secondary combustion equipment, 16...steam generating equipment, 17... dust collector, 18... induced draft fan, 19...flue gas processing equipment, 21...inner cylinder, 21a...heating chamber interior portion, 21c...inner circumferential surface, 211...feeding section, 211L...feeding lifter, 212...heating section, 212A...moisture evaporation zone, 212B...thermal decomposition zone, 213...discharge section, 22...heating chamber, 23...temperature control unit, 24...connecting pipe, 25...control system, 26...air supply unit, 27...heating unit, 28...steam supply unit, 29...temperature detecting unit, 30...control main unit, 31... air fan, 32...first pipe, 33...first control valve, 34...burner, 36...burner air fan, 37...second pipe, 38...second control valve, 39...third pipe, 40...third control valve, 41... fourth pipe, 42...fourth control valve, 43...flue gas duct, 51... agitation plate, 52...agitation plate, 52b.. .bent portion, 53...bracket, 54...gap, D1... upstream side, D2.. .downstream side, 0...axis, Z1... first control zone, Z2.. .second control zone, Z3.. .third control zone.

Claims

CLAIM(S)

1. A facility for manufacturing reformed coal, comprising carbonization equipment that comprises: an inner cylinder configured to rotate around an axis, into which coal is supplied from an end of the inner cylinder positioned at an upstream side in an extending direction of the axis, and from which reformed coal is discharged from an end of the inner cylinder positioned at a downstream side in the axis extending direction; a heating chamber covering the inner cylinder from an outside in a radial direction of the inner cylinder; and a plurality of connecting pipes arranged in the axis extending direction in the inner cylinder, the connecting pipes protruding beyond the inner cylinder in the radial direction and being opened in the heating chamber, wherein the facility further comprises: a temperature control unit configured to control a temperature inside the heating chamber by supplying an oxygen-containing gas into the heating chamber; and a flue gas duct through which gas in the heating chamber is discharged, and the heating chamber comprises a plurality of control zones defined by zoning an inside of the heating chamber into a plurality of sections in the axis extending direction, the temperature control unit is configured to control a temperature for each of the control zones, and the flue gas duct is connected to a control zone that is included in the control zones and positioned at a most upstream side in the axis extending direction.

2. The facility for manufacturing reformed coal according to claim 1, wherein the temperature control unit is configured to control a temperature inside the flue gas duct and a temperature inside the heating chamber to 600 degrees C or more.

3. The facility for manufacturing reformed coal according to claim 1 or 2, further comprising an agitation member protruding from an inner circumferential surface of the inner cylinder toward the axis and configured to agitate the coal.

4. The facility for manufacturing reformed coal according to claim 3, wherein the agitation member comprises a plurality of agitation members, and an agitation member included in the agitation members and disposed in a thermal decomposition zone at the downstream side in the axis extending direction of the inner cylinder is larger in an inclination angle with respect to the axis than an agitation member included in the agitation members and disposed in a moisture evaporation zone at the upstream side in the axis extending direction.

5. The facility for manufacturing reformed coal according to claim 4, wherein the inclination angle with respect to the axis of the agitation member disposed in the moisture evaporation zone is zero.

6. The facility for manufacturing reformed coal according to claim 4 or 5, wherein the agitation members are arranged in the axis extending direction within a range that accounts for more than 90% of a heating section formed by the moisture evaporation zone and the thermal decomposition zone.

7. The facility for manufacturing reformed coal according to any one of claims 3 to 6, wherein the agitation member and the inner circumferential surface of the inner cylinder define a gap.

8. The facility for manufacturing reformed coal according to claim 7, wherein a size of the gap is 10% to 25% of a dimension of the agitation member in the radial direction of the inner cylinder.

9. The facility for manufacturing reformed coal according to any one of claims 3 to 7, wherein the agitation member comprises a bent portion inclined to the radial direction of the inner cylinder.

10. The facility for manufacturing reformed coal according to claim 9, wherein the bent portion is formed in a range from 30% to 70% with respect to a height of the agitation member from the inner circumferential surface of the inner cylinder, at a position close to the axis of the agitation member, and an inclination angle of the bent portion with respect to the radial direction of the inner cylinder is in a range from 10 degrees to 45 degrees.

11. A method for manufacturing reformed coal using carbonization equipment that comprises: an inner cylinder configured to rotate around an axis, into which coal is supplied from an end of the inner cylinder positioned at an upstream side in an extending direction of the axis, and from which reformed coal is discharged from an end of the inner cylinder positioned at a downstream side in the axis extending direction; a heating chamber covering the inner cylinder from an outside in a radial direction of the inner cylinder; and a plurality of connecting pipes arranged in the axial extending direction in the inner cylinder, the connecting pipes protruding beyond the inner cylinder in the radial direction and being opened in the heating chamber, the method comprising: controlling a temperature inside the heating chamber by supplying an oxygen containing gas into the heating chamber; and discharging a gas present in the heating chamber, wherein the heating chamber comprises a plurality of control zones defined by zoning an inside of the heating chamber into a plurality of sections in the axis extending direction, in the controlling of the temperature, the temperature is controlled for each of the control zones, and in the discharging of the gas, the gas is discharged from a control zone that is included in the control zones and positioned at a most upstream side in the axis extending direction.

12. The method for manufacturing reformed coal according to claim 11, wherein, in the controlling of the temperature, the temperature inside the heating chamber is controlled to 600 degrees C or more.

13. The method for manufacturing reformed coal according to claim 11 or 12, further comprising: agitating the coal with an agitation member that protrudes from an inner circumferential surface of the inner cylinder toward the axis.

14. The method for manufacturing reformed coal according to claim 13, wherein the agitation member comprises a plurality of agitation members, an agitation member included in the agitation members and disposed at least in a thermal decomposition zone that is included in the control zones and positioned at the downstream side in the axis extending direction of the inner cylinder has an inclination angle inclined to the axis, and the coal agitated by the agitation member having the inclination angle moves upstream in the axis extending direction.

15. The method for manufacturing reformed coal according to claim 13 or 14, wherein the agitation member and the inner circumferential surface of the inner cylinder define a gap, and the coal agitated by the agitation member drops through the gap.

16. The method for manufacturing reformed coal according to any one of claims 13 to 15, wherein the agitation member comprises a bent portion inclined to the radial direction of the inner cylinder and the coal agitated by the agitation member drops from the bent portion.

Nippon Steel Engineering Co., Ltd. Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON

FLUE GAS

PROCESSING

EQUIPMENT

FLUE GAS

19

REFORMED COAL

DRAFT FAN

INDUCED

18

COLLECTOR

14 17 DUST COOLER

13

FIG 1

GENERATING EQUIPMENT 21 16 STEAM

22 12

23

SECONDARY EQUIPMENT COMBUTION

15 GAS) (OXYGEN-CONTAINING AIR 43

DRYER

AIR MOISTURE

VAPOR

10

HIGH MOISTURE 11 COAL WITH

CONTNET