COMBUSTIBLE WASTE INJECTION DEVICE AND METHOD FOR OPERATING THE SAME

Abstract

There is provided a combustible waste injection device and a method for operating the same which can suppress a landing combustion of a combustible waste and suppress excessive change of a flame state from a cement kiln burner even if a rate of using the combustible waste fluctuates. A combustible waste injection device according to the present invention has a combustible waste flow channel which is arranged in an inner side of the air flow channel in an innermost shell, is installed in parallel to an axial direction of the cement kiln burner device and is provided for flow feeding a combustible waste flow, and the combustible waste flow channel has an inclined surface having a rising slope toward the injection port near the injection port in such a manner that a flow channel width in a vertical direction is narrowed toward the injection port.

Claims

1. A combustible waste injection device which can be attached to a cement kiln burner device having at least one air flow channel in an inner side of a powdered-solid-fuel flow channel, the combustible waste injection device comprising: a combustible waste flow channel which is arranged in an inner side of the air flow channel in an innermost shell, is installed in parallel to an axial direction of the cement kiln burner device and is provided for flow feeding a combustible waste flow, wherein the combustible waste flow channel has an inclined surface having a rising slope toward the injection port near the injection port in such a manner that a flow channel width in a vertical direction is narrowed toward the injection port with a flow channel width in a horizontal direction maintaining.

2. The combustible waste injection device according to claim 1, wherein the inclined surface is positioned at a position where an opposite end portion to the injection port of the combustible waste flow channel in the axial direction is between 150 mm and 2000 mm away from the injection port, and an elevation angle thereof is between 1 degree and 4 degrees.

3. The combustible waste injection device according to claim 1, further comprising an assist air inflow port which can flow an assist air flow into the combustible waste flow channel toward the axis center of the combustible waste flow channel at a position where the inclined surface is formed in the combustible waste flow channel, wherein the assist air inflow port is arranged at a plurality of positions in a circumferential direction.

4. The combustible waste injection device according to claim 3, wherein the assist air inflow port is arranged at a plurality of positions sandwiching in a vertical direction a horizontal plane including the axis center of the combustible waste flow channel when cutting with a plane orthogonal to the axis center of the combustible waste flow channel.

5. The combustible waste injection device according to claim 4, wherein the combustible waste flow channel is adapted to be capable of ejecting the combustible waste flow upward in the vertical direction after the combustible waste flow is reduced in the direction of the axis center by the assist air flow flowing into from the assist air inflow port.

6. The combustible waste injection device according to claim 3, wherein the assist air inflow port is installed in a range between 10 mm and 600 mm from the injection port of the combustible waste flow channel.

7. A method for operating the combustible waste injection device according to claim 1, wherein the method comprises ejecting the combustible waste flow from the combustible waste flow channel vertically upward from the horizontal plane.

8. The method for operating the combustible waste injection device according to claim 7, further comprising an assist air inflow port which can flow an assist air flow into the combustible waste flow channel toward the axis center of the combustible waste flow channel at a position where the inclined surface is formed in the combustible waste flow channel, wherein the assist air inflow port is arranged at a plurality of positions in a circumferential direction, and wherein an upward assist air flow rate flowed into from the vertically lower side of the horizontal plane is equal to or more than a downward assist air flow rate flowed into from the vertically upper side of the horizontal plane.

9. The method for operating the combustible waste injection device according to claim 8, wherein a total amount of the air flow rates flowed into the combustible waste flow channel from the assist air inflow port is between 5 volume % to 65 volume % of the primary air flow rate flowing in the combustible waste flow channel.

10. The method for operating the combustible waste injection device according to claim 8, wherein a rate of the downward assist air flow rate with respect to the upward assist air flow rate is between 0.5 and 1.0.

11. The method for operating the combustible waste injection device according to claim 8, wherein an inflow angle of the assist air flow flowed into the combustible waste flow channel is greater than 0 degrees and equal to or less than 90 degrees with respect to the flow feeding direction of the combustible waste flow which flow feeds within the combustible waste flow channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 is a view schematically showing a center portion at a tip end portion of an embodiment of a cement kiln burner device to which a combustible waste injection device according to the present invention is attached.

[0039] FIG. 2A is a vertical cross sectional view schematically showing a tip end portion of the embodiment of the combustible waste injection device according to the present invention.

[0040] FIG. 2B is a horizontal cross sectional view schematically showing the tip end portion of the embodiment of the combustible waste injection device according to the present invention.

[0041] FIG. 3 is a partially enlarged view of FIG. 2A.

[0042] FIG. 4A is a vertical cross sectional view schematically showing a tip end portion of the other embodiment of the combustible waste injection device according to the present invention.

[0043] FIG. 4B is a horizontal cross sectional view schematically showing the tip end portion of the other embodiment of the combustible waste injection device according to the present invention.

[0044] FIG. 5 is a view schematically showing an example of a structure of the combustible waste injection device shown in FIGS. 4A and 4B.

[0045] FIG. 6 is a view schematically showing a center portion at a tip end portion of the other embodiment of the cement kiln burner device to which the combustible waste injection device according to the present invention is attached.

[0046] FIG. 7 is a view schematically showing a tip end portion of an embodiment of a cement kiln burner device to which a combustible waste injection device used in simulation is attached.

[0047] FIG. 8 is a graph showing a result of simulation according to a gas temperature distribution within cement kilns according to Examples 1 to 5 and Comparative Examples 1 to 2 in the case where a waste plastic having a diameter of 30 mm is used as a supplemental fuel at a fixed amount with respect to a main fuel (a pulverized coal) under a condition for operating shown in Table 2, with the combustible waste injection device shown in FIG. 7.

MODE FOR CARRYING OUT THE INVENTION

[0048] A description will be given below of embodiments of a combustible waste injection device and a method for operating the same according to the present invention with reference to the accompanying drawings. The following drawings are schematically shown, and dimension ratios of the drawings do not match up with actual dimension ratios.

[0049] FIG. 1 is a view schematically showing a center portion of a tip end portion in an embodiment of a cement kiln burner device to which a combustible waste injection device according to the present invention is attached. In FIG. 1, FIG. 1(a) is a horizontal cross sectional view of the cement kiln burner device including the attached combustible waste injection device, and FIG. 1(b) is a vertical cross sectional view of the same. The horizontal cross sectional view indicates a cross sectional view obtained by cutting the cement kiln burner device with a plane which is orthogonal to an axial direction of the device, and the vertical cross sectional view indicates a cross sectional view obtained by cutting the cement kiln burner device with a plane which is parallel to the axial direction of the device.

[0050] In FIG. 1, a coordinate system is set by setting the axial direction of the cement kiln burner device (a direction of a primary air flow) to a Y direction, a vertical direction to a Z direction, and a direction which is orthogonal to a YZ plane to an X direction. In the following description, a description will be given by appropriately referring to the XYZ coordinate system. Describing by using the XYZ coordinate system, FIG. 1(a) corresponds to a cross sectional view when the cement kiln burner device is cut by the XZ plane, and FIG. 1(b) corresponds to a cross sectional view when the cement kiln burner device is cut by the YZ plane. In more detail, FIG. 1(b) corresponds to a cross sectional view when the cement kiln burner device is cut by the YZ plane in a cement kiln side end portion (a leading end surface of the cement kiln burner device).

[0051] Each of XYZ coordinate systems illustrated in FIGS. 2A to 4B, 6 and 7 mentioned later has the same axial relationship as the XYZ coordinate system illustrated in FIG. 1.

[0052] As shown in FIG. 1(a), a combustible waste flow channel 3 of a combustible waste injection device 2 attached to a cement kiln burner device 1 is arranged in an inner side of a powdered-solid-fuel flow channel 21 which is concentrically arranged in the cement kiln burner device 1, and at least one air flow channel 22 which is arranged inside in adjacent to the powdered-solid-fuel flow channel 21. An oil flow channel 31 for supplying a heavy oil can be arranged in an inner side of the air flow channel 22 in adjacent to the combustible waste flow channel 3 of the combustible waste injection device 2.

[0053] In FIG. 1, the air flow channel 22 has a swirl vane 22a serving as a swirling means in a cement kiln side end portion (in the vicinity of the injection port side). More specifically, an air flow ejected out of the air flow channel 22 forms a swirl air flow which is positioned inside a powdered-solid-fuel flow ejected out of the powdered-solid-fuel flow channel 21. The swirl vane 22a may be structured such that a swirl angle can be adjusted at a time point before the cement kiln burner device 1 starts operation.

[0054] As shown in FIG. 1(b), in an inner portion of the cement kiln burner device 1, on a bottom surface of the combustible waste flow channel 3 is formed an upward slope 8 near the injection port side in a vertical direction (Z direction). The upward slope 8 corresponds to inclined surface. Further, in the present embodiment, as shown in FIG. 1(b), in the inner portion of the cement kiln burner device 1, an assist air flow channel 4 is provided in an outer side of the combustible waste flow channel 3, and is structured such that an assist air can flow into the combustible waste flow channel 3 via an assist air inflow port 5. In this regard, a description will be given below with reference to FIGS. 2A and 2B.

[0055] The upward slope 8 is not limited in its specific mode and method as long as the bottom surface of the combustible waste flow channel 3 is formed with a slope. As an example, an inner wall surface itself of the combustible waste flow channel 3 may form the upward slope 8 by forming so that a thickness of an inner wall corresponding to the bottom portion of the combustible waste flow channel 3 becomes thicker little by little within a predetermined area in the Y direction. As the other example, a surface of another member may form the upward slope 8 by providing another member having a height which is changed little by little toward the Y direction, on an inner wall corresponding to the bottom portion of the combustible waste flow channel 3 within a predetermined area in the Y direction. In any case, the upward slope 8 is formed in the combustible waste flow channel 3, so that a flow channel width of the combustible waste flow channel 3 in the vertical direction is narrowed toward the injection port.

[0056] FIGS. 2A and 2B are views schematically showing a tip end portion of an embodiment of the combustible waste injection device 2 according to the present invention. FIG. 2A is a vertical cross sectional view of the combustible waste injection device 2, and FIG. 2B is a horizontal cross sectional view (corresponding to (a)) at a position where a Y-coordinate in FIG. 2A is Y1 (hereinafter, abbreviated simply to as position of Y1), and a horizontal cross sectional view (corresponding to (b)) at a position where the Y-coordinate is Y2 (hereinafter, abbreviated simply to as position of Y2). The position of Y1 corresponds to the vicinity of the tip end portion of the combustible waste flow channel 3 (that is, the vicinity of the injection port), and the position of Y2 corresponds to a position in an upstream side of the position of Y1 and away from the tip end portion of the combustible waste flow channel 3.

[0057] Further, as shown in FIG. 2A, the upward slope 8 is formed in the bottom surface of the combustible waste flow channel 3. In the upward slope 8, an elevation angle (angle of inclination) in relation to the horizontal plane (XY plane) is between 1 degree and 4 degrees. Further, the upward slope 8 is formed toward the injection port from a position which is 150 mm to 2000 mm away from the injection port in the Y direction.

[0058] Further, in the present embodiment, as shown in FIG. 2B, the assist air flow channel 4 is arranged in an outer side of the combustible waste flow channel 3. In more detail, the assist air flow channel 4 according to the present embodiment is concentrically arranged in an outer side of the combustible waste flow channel 3 formed into a cylindrical shape, and is divided by a partition member 6 into two flow channels, a vertically upper side assist air flow channel 4-1 and a vertically lower side assist air flow channel 4-2.

[0059] As shown in FIG. 2B(b), an assist air inflow port 5 communicating the assist air flow channel 4 (4-1 and 4-2) and the combustible waste flow channel 3 is installed at the position of Y2, and is structured such that the assist air flowing through the assist air flow channel 4 can flow into the combustible waste flow channel 3 toward an axis center 3c of the combustible waste flow channel 3. In the present embodiment, the combustible waste flow channel 3 is provided at the position of Y2, with assist air inflow ports 5 (5-1 to 5-10) which are arranged at ten positions in a circumferential direction. In more detail, five assist air inflow ports (5-1 to 5-3, 5-9 and 5-10) are arranged in the assist air flow channel 4-1 side (vertically upper side), and five assist air inflow ports (5-4 to 5-8) are arranged in the assist air flow channel 4-2 side (vertically lower side).

[0060] In FIG. 2A, for convenience of illustration, only the assist air inflow ports (5-1 and 5-6) appear on the drawing among ten assist air inflow ports 5 (5-1 to 5-10).

[0061] A dedicated blower (not shown) or flow rate regulating valve (not shown) is connected to each of the assist air flow channels (4-1 and 4-2), and can independently control the assist air flow rate which is delivered to each of the assist air flow channels (4-1 and 4-2).

[0062] FIG. 3 is a view schematically showing the tip end portion of the embodiment of the combustible waste injection device 2 according to the present invention shown in FIG. 2A by enlarging a periphery of the assist air inflow ports (5-1 and 5-6).

[0063] As shown in FIG. 3, an assist air delivery tool 7 is installed in the assist air inflow ports (5-1 and 5-6) communicating the combustible waste flow channel 3 and the assist air flow channel 4. The assist air delivery tool 7 is provided for controlling an inflow angle (1 and 2) which a direction of the assist air AA flowed into the combustible waste flow channel 3 forms with respect to the direction of the combustible waste RF flowing within the combustible waste flow channel 3. In FIG. 3, there are schematically shown respective modes of the assist air delivery tool 7 in the case of the inflow angle =1, and the case of the inflow angle =2.

[0064] The inflow angle can be made more than 0 degrees and equal to or less than 90 degrees. In the case where the inflow angle of the assist air AA is 0 degrees, an effect of changing the flow of the combustible waste RF by the assist air AA can be hardly obtained, and in the case where the inflow angle goes beyond 90 degrees, the flow of the combustible waste RF is decelerated by the assist air AA and is excessively agitated. As a result, both the cases are not preferable.

[0065] FIGS. 4A and 4B are views schematically showing a tip end portion of the other embodiment of the combustible waste injection device 2 according to the present invention. FIG. 4A is a vertical cross sectional view of the combustible waste injection device 2 in the same manner as FIG. 2A, and FIG. 4B is a horizontal cross sectional view (corresponding to (a)) at a position of Y1 in FIG. 4A and a horizontal cross sectional view (corresponding to (b)) at a position of Y2, in the same manner as FIG. 2B. For convenience of illustration, the assist air inflow port 5 is not illustrated in FIG. 4A.

[0066] In the embodiment shown in FIG. 4B, the combustible waste flow channel 3 is provided at the position of Y2, with assist air inflow ports 5 (5-11 to 5-16) which are arranged at six positions in a circumferential direction. Further, the combustible waste flow channel 3 is provided with dedicated assist air flow channels (4-3 to 4-8) every assist air inflow ports (5-11 to 5-16). As a result, the assist air flow rates supplied to the respective assist air flow channels (4-3 to 4-8) can be independently controlled by respectively connecting dedicated blowers (not shown) or flow rate regulating valves (not shown) to the assist air flow channels 4-3 to 4-8. A description will be given of this regard with reference to FIG. 5.

[0067] FIG. 5 is a view schematically showing an example of a structure of the combustible waste injection device shown in FIG. 4. The combustible waste injection device 2 illustrated in FIG. 5 is constructed by valuing an easy control, and is provided with three blowing fans (F1 to F3), and six flow rate regulating valves (B113, B114, B118, B135, B136, and B137). The flow rate regulating valves (B113, B114, B118, B135, B136, and B137) are constructed, for example, by a gas valve.

[0068] The combustible waste RF supplied to a combustible waste transfer pipe 12 is supplied to the combustible waste flow channel 3 of the combustible waste injection device 2 by an air flow formed by the blowing fan F1. The air supplied from the blowing fan F2 is supplied as an assist air AA to the assist air flow channel 4 (4-3, 4-4, and 4-8) via an air pipe 11. In more detail, the air pipe 11 is branched by three branched pipes (113, 114, and 118), and the branched pipes are respectively communicated with the three assist air flow channels (4-3, 4-4, and 4-8). In the same manner, the air pipe 13 supplying the assist air AA from the blowing fan F3 is branched by three branched pipes (135, 136, and 137) and are communicated with three assist air flow channels (4-5, 4-6, and 4-7).

[0069] The branched pipes (113, 114, 118, 135, 136, and 137) are respectively provided with variable type flow rate regulating valves (B113, B114, B118, B135, B136, and B137), and the flow rate of the assist air AA circulating the branched pipes (113, 114, 118, 135, 136 and 137) can be independently controlled by regulating opening degrees of the flow rate regulating valves mentioned above.

[0070] More specifically, in the case of the combustible waste injection device 2 shown in FIGS. 4A, 4B and 5, the flow rate of the assist air AA can be independently every assist air inflow ports 5 (5-11 to 5-16) since the assist air inflow ports 5 (5-11 to 5-16) are provided in correspondence to the respective assist air flow channels 4 (4-3 to 4-8). As a result, it is possible to optionally change a rate of using the powdered-solid-fuel (the main fuel) and the combustible waste (the supplemental fuel) while maintaining the optimum state of the flame from the cement kiln burner.

[0071] Further, the combustible waste flow can be ejected from the combustible waste flow channel 3 vertically upward (+Z direction) of the horizontal plane (XY plane) since the upward slope 8 is formed on the bottom surface near the injection port of the combustible waste flow channel 3. As a result, it is possible to continue the floating state of the combustible waste within the cement kiln for a long period of time.

[0072] More specifically, as shown in FIG. 6, the combustible waste injection device 2 according to the present invention may be provided with neither assist air flow channel 4 nor assist air inflow port 5 while being provided with the upward slope 8 in the bottom surface of the combustible waste flow channel 3. However, the effect of ejecting the combustible waste flow further vertically upward can be regulated by providing the assist air flow channel 4 and the assist air inflow port 5 and making the assist air AA flow into toward the axis center direction of the combustible waste flow channel 3 such as the combustible waste injection device 2 shown in FIG. 1. Therefore, it is possible to further enhance an effect of setting the floating state of the combustible waste RF within the cement kiln to a preferable state.

[0073] The inventors of the present invention have found a basic limitation region for optimizing a control factor of the combustible waste injection device 2 by analyzing a flame shape from the cement kiln burner, a gas temperature distribution within the cement kiln, an oxygen concentration distribution within the cement kiln and a degree of an air flow turbulence within the cement kiln according to a combustion simulation (software: FLUENT produced by ANSYS JAPAN K. K.) of the cement kiln burner device 1 having the combustible waste injection device 2 attached thereto.

[0074] FIG. 7 schematically illustrates the structure of the cement kiln burner device 1 including the combustible waste injection device 2 used in the present simulation following to FIG. 1. The cement kiln burner device 1 shown in FIG. 7 is provided in addition to the structure shown in FIG. 1 with an air flow channel 23 which is arranged in an outer side of a powdered-solid-fuel flow channel 21 and has a swirl vane 23a arranged therein, and an air flow channel 24 which is arranged further outside the air flow channel 23. The air flow channel 24 is a flow channel which forms a straight air flow. More specifically, the cement kiln burner device 1 of a subject to be investigated by simulation is a so-called four-channel type burner device including totally four flow channels; an air flow channel 22 forming a swirl air flow, a powdered-solid-fuel flow channel 21 forming a swirl main fuel flow, an air flow channel 23 forming a swirl air flow, and an air flow channel 24 forming a straight air flow, from an inner side, as shown in FIG. 7(a).

[0075] Example 1 mentioned later is a structure in which the cement kiln burner device 1 shown in FIG. 7 is provided with neither the assist air flow channel 4 nor the assist air inflow port 5, and corresponds to a structure in which the cement kiln burner device 1 in FIG. 6 is changed to 4-channel type.

[0076] The following Table 1 is an example of the basic limitation region according to the combustible waste injection device 2 which has been found under the specification and the condition for operating of the following cement kiln burner device 1. Table 1 corresponds to the embodiment of the combustible waste injection device 2 exemplified in FIG. 2.

<Specification of Cement Kiln Burner Device 1>

[0077] Number of channels: four channels (swirl air flow, swirl main fuel flow, swirl air flow and straight air flow from innermost shell side)

[0078] Combustible waste injection device 2: arranged in an inner side of an air flow channel 22 forming the swirl air flow and attached to a lower side of an axis center of the cement kiln burner device 1

[0079] Diameter of burner tip of cement kiln burner device 1: 700 mm

[0080] Inner diameter of injection port of combustible waste injection device 2: 175 mm

[0081] Forming area of upward slope 8: area from a position which is 300 mm in Y direction from an injection port (end portion) of a combustible waste flow channel 3, to the injection port (end portion)

[0082] Assist air inflow port 5: five circular holes having diameter of 16 mm in each of an upper side and a lower side in a vertical direction (30 degrees intervals in a range 60 degrees with respect to vertical axis)

<Condition for Operating Cement Kiln Burner Device 1>

[0083] The amount of combustion of main fuel C flowing in powdered-solid-fuel flow channel 21: 12 t/hour

[0084] The amount of waste plastic (non-rigid plastic) which was processed as combustible waste RF: 5 t/hour

[0085] The dimension of waste plastic serving as combustible waste RF: circular sheet shape obtained by punching a sheet having a thickness 0.5 mm with a diameter 30 mm

[0086] The primary air flow rate (total amount of four channels) and temperature: 15000 Nm.sup.3/hour, 30 C.

[0087] The secondary air flow rate and temperature: 100000 Nm.sup.3/hour, 900 C.

[0088] The primary air flow rate from combustible waste injection device 2 and temperature: 5000 Nm.sup.3, 30 C.

[0089] The blowing method of assist air AA from combustible waste injection device 2 and temperature: the assist air AA is added in a state in which the primary air flow rate from the combustible waste injection device 2 keeps the above value, 30 C.

TABLE-US-00001 TABLE 1 Cement kiln burner device 1 in FIG. 7 Elevation angle of 1 4 upward slope 8 Assist air flow rate 5 volume % to 65 volume % of primary air amount of combustible waste injection device 2 Rate r in vertical (downward assist airflow rate)/(upward assist direction of assist airflow rate) is 0.5 to1.0 airflow rate Position of assist air 10 nun to 600 nun from injection port (end inflow port 5 portion) of combustible waste flow channel 3 Inflow angle 9 of 0 90 assist air

[0090] In Table 1, there are listed as basic limitation regions an elevation angle of the upward slope 8, an assist air AA flow rate (volume % of all the assist air flow rates in relation to a primary air flow rate of the combustible waste injection device 2), a rate r of each of the assist air flow rates flowed into from a vertically upper side of a horizontal plane including an axis center and flowed into from a vertically lower side of the horizontal plane including the axis center [(downward assist air flow rate)/(upward assist air flow rate)], a distance (mm) of the assist air inflow port 5 from an end portion of the combustible waste flow channel 3, and an inflow angle () of the assist air AA flowed into the combustible waste flow channel 3 from the assist air inflow port 5.

[0091] Among the items mentioned above, the elevation angle of the upward slope 8, the flow rate of the assist air AA, the position of the assist air inflow port 5, and the rate r of the assist air AA amount in the vertical direction are important.

[0092] As mentioned above, it is necessary to form a good mixed state of the combustible waste RF, the main fuel C and the secondary air in order to facilitate regulation for obtaining a stable flame even when the fuel composition used for the cement kiln burner device 1 changes. In spite of the above fact, it is possible to regulate a degree of throttling of the combustible waste flow flowing through the combustible waste flow channel 3 by regulating the flow rate of the assist air AA, whereby it is possible to independently regulate a degree of diffusion of the combustible waste RF ejected out of the combustible waste injection device 2 during operation.

[0093] Taking into consideration the circumstance mentioned above, a flow rate V (Nm.sup.3/hour) of the assist air AA flowed into the combustible waste flow channel 3 from the assist air inflow port 5 per unit time is preferably between 5 volume % and 65 volume % of a primary air flow rate V.sub.0 (Nm.sup.3/hour) flowing through the combustible waste flow channel 3. In the case where V/V.sub.0 is less than 5 volume %, a throttle effect of the combustible waste flow cannot be obtained by the assist air AA, and in the case where V/V.sub.0 goes beyond 65 volume %, the degree of diffusion of the combustible waste flow is enlarged, so that a part of the combustible waste RF may come into collision with an upper inner wall of the cement kiln. Further, in the case where the combustible waste is diffused in such a degree that a part of the combustible waste RF comes into collision with the kiln inner wall, the flame shape of the cement kiln burner is greatly disturbed, so that the quality of the cement clinker becomes unstable and the heat loss of the firebrick within the cement kiln is enlarged.

[0094] Further, the degree of diffusion of the combustible waste RF ejected out of the combustible waste injection device 2 can be regulated by changing the position (in more detail, the position in the Y direction) of the assist air inflow port 5 in the case where the flow rate of the assist air AA is fixed.

[0095] Taking into consideration the circumstance mentioned above, a distance in the Y direction from the injection port (end portion) of the combustible waste flow channel 3 to the assist air inflow port 5 is preferably within a range between 10 mm and 600 mm. In the case where the distance mentioned above is less than 10 mm, the degree of diffusion of the flow of the combustible waste RF is enlarged, and a part of the combustible waste RF may come into collision with the upper inner wall of the cement kiln. Further, in the case where the distance in the Y direction from the injection port of the combustible waste flow channel 3 to the assist air inflow port 5 goes beyond 600 mm, the diffusion effect of the combustible waste RF generated by the assist air AA may disappear.

[0096] By regulating the elevation angle of the upward slope 8 provided in the bottom surface of the combustible waste flow channel 3 regardless of the introduction of the assist air AA, it is also possible to regulate an angle of ejection of the combustible waste flow ejected from the combustible waste flow channel 3. It is possible to continue the floating state of the combustible waste RF within the cement kiln for a long period of time since the angle of ejection of the combustible waste flow is appropriately regulated.

[0097] Taking into consideration the circumstances mentioned above, the angle (the elevation angle ) of the upward slope 8 is preferably in a range between 1 degree and 4 degrees. In the case where the elevation angle of the upward slope 8 is less than 1 degree, it is necessary to execute an action of making the combustible waste flow upward only by the assist air AA, and an energy amount required for blowing the assist air AA is excessively required. Further, in the case where the elevation angle of the upward slope 8 is greater than 4 degrees, the diffusion effect by the assist air AA is added, so that there is a risk that the combustible waste RF may partly come into collision with the upper inner wall of the cement kiln.

[0098] Further, the rate in the vertical direction of the flow rate of the assist air AA is important because it is possible to vertically regulate the ejecting direction of the combustible waste RF by regulating the rate between the downward assist air flow rate and the upward assist air flow rate, thereby changing the direction of the combustible waste RF ejected from the combustible waste injection device 2 further vertically upward. As a result, it is possible to regulate the floating state of the combustible waste RF ejected in the good diffusion state by the assist air AA to a further preferable state.

[0099] Taking into consideration the circumstances mentioned above, it is preferable to set the rate r of the downward assist air flow rate flowed into from the vertically upper side of the horizontal plane including the axis center in relation to the upward assist air flow rate flowed into from the vertically lower side of the horizontal plane including the axis center to a range between 0.5 and 1.0. In the case where the rate r is less than 0.5, the combustible waste flow blows up from the lower side greatly, and the combustible waste RF may partly come into collision with the upper inner wall of the cement kiln. Further, in the case where the rate r is greater than 1.0, that is, in the case where the downward assist air flow rate is greater than the upward assist air flow rate, a downward force is applied to the combustible waste flow and may generate a great disturbance in the combustion waste flow in combination with the upward effect by the upward slope.

[0100] As mentioned above, according to the present invention, it is possible to optimize the condition for operating the combustible waste injection device 2 so as to stabilize the flame state of the cement kiln burner by setting the elevation angle of the upward slope 8, the position of the assist air inflow port 5 and the inflow angle within the range shown by Table 1 before the operation of the combustible waste injection device 2, and further regulating the assist air flow rate V, and the rate r of the assist air flow rate from the vertical direction by means of the blowing fan and/or the flow rate regulating valve when the combustible waste injection device 2 is operated. In the case of the combustible waste injection device 2 according to the aspect shown in FIG. 6 which is provided with neither the assist air flow channel 4 nor the assist air inflow port 5, the flame state of the cement kiln burner can be stabilized by regulating the elevation angle of the upward slope 8.

[0101] Next, a description will be given of a combustion simulation about a rate (a kiln inside falling rate) that the combustible waste RF (here, non-rigid plastic) performs landing combustion in the case where each of the items in Table 1 is changed.

[0102] In particular, the case where each of the items in Table 1 is changed was investigated according to simulation (software: FLUENT produced by ANSYS JAPAN K. K.) in the case where the specification and the condition for operating of the cement kiln burner device 1 mentioned above are fixed. A set value of each of the items in the simulation is shown in Table 2. As a current example (comparative example) which is not provided with the upward slope 8 and does not use the assist air AA, an amount of combustible waste RF which was processed was set to two levels (5 t/hour and 2 t/hour).

[0103] A kiln inside falling rate of the combustible waste RF (non-rigid plastic having a diameter of 30 mm and a thickness of 0.5 mm) obtained as a result of the simulation is shown in Table 3, and gas temperature distributions within the kiln of Examples 1 to 5 and Comparative Examples 1 to 2 are shown in FIG. 8.

TABLE-US-00002 TABLE 2 Assist air flow rate((assist Rate r of assist air Position of assist elevation angle air flow rate)/(primary air flow rate in vertical air flow inlet 5 of upward amount flowing through direction (downward (distance from Inflow angle of slope 8 combustible waste flow assist air flow rate)/ end portion) assist air AA () channel 3))(vol %) (upward assist air flow rate) (mm) () Example 1 2 (Without (Without (Without (Without assist air) assist air) assist air) assist air) Example 2 2 25 0.80 50 90 Example 3 2 25 0.67 50 90 Example 4 4 25 0.80 50 90 Example 5 2 50 0.80 50 90 Comparative Example 1 (Without (Without (Without (Without (Without (RF: 5 t/hour) upward slope) assist air) assist air) assist air) assist air) Comparative Example 2 (Without (Without (Without (Without (Without (RF: 2 t/hour) upward slope) assist air) assist air) assist air) assis tair)

TABLE-US-00003 TABLE 3 Kiln inside falling rate of combustible waste RF (mass %) Example 1 2.1 Example 2 1.4 Example 3 0.8 Example 4 0.6 Example 5 0.0 Comparative Example 1 3.0 Comparative Example 2 0.5

[0104] According to the results in Table 3, it is confirmed that the kiln inside falling rate of the combustible waste RF can be sufficiently lowered in the level of each of Examples 1 to 5 in comparison with the level of Comparative Example 1 in which the condition for the amount of the combustible waste RF which was processed is in common with 5 t/hour. More specifically, the kiln inside falling rate can be lowered in comparison with Comparative Example 1 corresponding to the current condition for operating even in Example 1 which does not utilize the assist air AA, and the effect of suppressing the landing combustion of the combustible waste RF can be therefore confirmed by the provision of the upward slope 8. Further, according to Examples 2 to 5 introducing the assist air AA in addition to the upward slope 8, the kiln inside falling rate is further lowered in comparison with Example 1.

[0105] According to Examples 3 to 5, the value of the kiln inside falling rate can be lowered to one third or less in comparison with Comparative Example 1. In particular, according to Example 5, the kiln inside falling rate 0% is achieved. As a result, according to the combustible waste injection device and the method for operating the combustible waste injection device of the present invention, it is confirmed that the combustible waste RF can be effectively burnt.

[0106] Further, in the temperature distribution of the gas within the cement kiln shown in FIG. 8, the temperature distribution of the gas in each of Examples 1 to 5 is substantially identical to that of the case of Comparative Example 2 where the amount of the combustible waste RF which was processed is set to 2 t/hour under the current condition for operating. The condition for operating of Comparative Example 2 is obtained by setting the supply amount of the combustible waste RF less than each of the examples, in which the kiln inside falling rate of the combustible waste RF is 0.5 mass %, corresponding to a good kiln burner combustion state. On the other hand, in Comparative Example 1 having the same amount of the combustible waste RF which was processed as the present Example (5 t/hour) under the current condition for operating, a lot of combustible wastes RF perform land combustion, that is, the kiln inside falling rate of the combustible waste RF is 3.0 mass %, as well as the temperature of the gas within the cement kiln is greatly lowered. More specifically, according to the present invention, it is confirmed that the combustible waste RF can be utilized as the supplemental fuel without greatly changing the temperature distribution of the gas within the cement kiln.

[0107] In other words, according to the present invention, it can be understood that the combustible waste can be utilized as the supplemental fuel while keeping an optimum combustion state of the cement kiln burner.

[0108] The installing number and the installing place of the assist air inflow port provided in the combustible waste injection device are not limited to the structures of the embodiments mentioned above.

DESCRIPTION OF REFERENCE SIGNS

[0109] 1 cement kiln burner device [0110] 2 combustible waste injection device [0111] 3 combustible waste flow channel [0112] 3c axis center of combustible waste flow channel [0113] 4 assist air flow channel [0114] 4-1, 4-2 assist air flow channel [0115] 4-3, 4-4, 4-5, 4-6, 4-7, 4-8 assist air flow channel [0116] 5 assist air inflow port [0117] 5-1, 5-2, 5-3, 5-4, 5-5, 5-6, 5-7, 5-8, 5-9, 5-10 assist air inflow port [0118] 5-11, 5-12, 5-13, 5-14, 5-15, 5-16 assist air inflow port [0119] 6 partition member [0120] 7 assist air delivery tool [0121] 8 upward slope [0122] 11 air pipe [0123] 12 combustible waste transfer pipe [0124] 13 air pipe [0125] 21 powdered-solid-fuel flow channel [0126] 22 air flow channel (first air flow channel) [0127] 22a swirl vane [0128] 31 oil flow channel [0129] 113, 114, 118 branched pipe [0130] 135, 136, 137 branched pipe [0131] AA assist air [0132] B113, B114, B135, B136, B137, B118 flow rate regulating valve [0133] F1, F2, F3 blowing fan [0134] RF combustible waste [0135] inflow angle of assist air [0136] elevation angle of upward slope