Method of operating horizontal continuous dryer of conductive heat transfer type

Abstract

To develop a novel method of operating a horizontal continuous dryer of a conductive heat transfer type, capable of achieving a stable and highly efficient operation even when the apparent density of the treating object changes.SOLUTION: A method of operating a horizontal continuous dryer of a conductive heat transfer type is characterized by optimizing one or both of a dried product discharge rate F3 from a body shell 10 or a treating object charging rate F1 into the body shell 10, by measuring the entire weight WITR of the treating object M staying in the body shell 10 and using the entire weight WITR of the treating object M staying therein, in a device that comprises a heat transfer member disposed in the body shell 10, rotates the heat transfer member while flowing a heating medium therethrough, charges the treating object M into the body shell 10, and brings the treating object M into contact with the heat transfer member while allowing the treating object M to stay in the body shell 10, to obtain the dried product D of the treating object M.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a horizontal continuous conduction heat transfer dryer suitable for drying materials in a muddy, cake-like, powdery or granular form, and in particular to an operating method of a horizontal continuous conduction heat transfer dryer capable of satisfactorily drying materials whose properties fluctuate greatly, such as dehydrated sludge from sewage. [Background technology]

[0002] Recently, environmental conservation efforts have become more common, and companies and other organizations are drying and concentrating general waste such as food waste and food processing residues, as well as sewage sludge, in order to reduce their volume and prevent decay, before recycling or disposing of them.

[0003] One of the devices used for drying such sludge and the like is a horizontal continuous conduction heat transfer dryer 1'. As shown in Fig. 9, for example, this device is provided with a multi-tube heating pipe 11' in a main body shell 10', and this multi-tube heating pipe 11' is rotated while heating steam is passed through it, and the material to be treated M is brought into contact with this pipe to evaporate moisture (for example, see Patent Document 1). The material to be treated M supplied into the main shell 10' from the inlet 101' is lifted up by the lifter 117' and moves toward the overflow outlet 102' as the drying progresses, and is discharged to the outside from the overflow outlet 102' via the chute 12' in the form of a dried product D.

[0004] When operating such a horizontal continuous conduction heat transfer dryer 1', the workpieces M (which have been dried) occupying about 50% of the volume of the main shell 10' are retained in the main shell 10' as seed material, and the moisture content of the newly added workpieces M is reduced, thereby enabling efficient drying.

[0005] For this reason, it is necessary to grasp and adjust the retention rate of the workpiece M within the main shell 10'. However, because direct measurement by installing a level meter is difficult due to problems such as dust adhesion, indirect methods such as the following have been adopted. That is, in the horizontal continuous conduction heat transfer dryer 1', the current value of the motor which is the driving source of the multi-tube heating tube 11' varies depending on the load of the multi-tube heating tube 11'. By measuring this current value, the retention rate of the workpiece M in the main shell 10' can be obtained based on a calibration curve (retention rate-current value curve) prepared in advance. The discharge amount of the dried product D is controlled by changing the opening and closing time of the barrier plate 108' by the air cylinder 109', and the retention rate within the main shell 10' is adjusted (see Patent Document 1).

[0006] However, since the calibration curve (retention rate-current value curve) shows different characteristics depending on the properties of the workpiece M, if the properties of the workpiece M fed into the feed port 101' change during operation, the retention rate calculated from the current value will no longer be accurate. Therefore, if the operator does not notice the change in the properties of the workpiece M, the retention rate will be misjudged. According to the conventional method described above, there was no problem when handling materials M whose properties change very little, such as waste generated in food factories, etc., but when handling materials M whose properties (especially the apparent density of dried products) change drastically, such as dehydrated sludge from sewage, the control was, so to speak, off the mark, and the retention rate of the materials M in the main shell 10' became excessive, causing clogging, or causing poor drying such as insufficient drying or over-drying. In severe cases, it became difficult to continue automatic operation. Incidentally, the properties of the dewatered sewage sludge vary greatly depending on the location where it is collected, and even if it is collected from the same location, its properties vary greatly depending on the time of collection (for example, day or night, summer or winter). Therefore, it is one of the most difficult to grasp the drying conditions inside the horizontal continuous conduction heat transfer dryer 1'.

[0007] In order to solve such problems, the applicant has devised a new operating method for a horizontal continuous conduction heat transfer dryer, which measures the apparent density of the dried product D discharged from the horizontal continuous conduction heat transfer dryer 1' and uses this measurement value as a judgment factor to adjust the amount of the workpiece M being processed in the shell body 10' to an amount that allows the horizontal continuous conduction heat transfer dryer 1' to operate efficiently, thereby enabling the drying process to be carried out appropriately even for workpieces M whose properties vary greatly (see Patent Document 2).

[0008] According to this invention, the retention rate in the main shell 10' is adjusted according to the apparent density of the dried product D discharged from the main shell 10'. Therefore, even if the apparent density of the dried product D changes due to a change in the physical properties of the material M to be treated, a stable operation can be performed without causing clogging of the main shell 10' by the material M to be treated, or insufficient or over-drying of the dried product D. In addition, the current value flowing through the motor that rotates the multi-tube heating tube 11' is compared with the heating tube drive current setting value corresponding to the apparent density of the dried product D to change the opening and closing time of the dam plate 108', so that the retention rate of the material M to be treated in the main shell 10' can be kept constant. In particular, by maintaining a retention rate with good heat transfer efficiency between the material M to be treated and the multi-tube heating tube 11', a dried product D with little moisture fluctuation can be obtained and an efficient operation can be performed.

[0009] However, the above invention is based on the assumption that the apparent density of the retained goods of the input workpiece M, i.e., the apparent density of the retained goods in the main shell 10', is constant, and determines an increase or decrease in the retained goods by the current value of the motor driving the multi-tube heating tube. When the apparent density of the retained goods fluctuates, the change in the retained goods weight can be detected by the current value, but the change in the retained goods volume cannot be detected. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent Publication No. 2005-331210 [Patent Document 2] Patent No. 5330920 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made against this background, and has as its technical objective the development of a new operating method for a horizontal continuous conduction heat transfer dryer that can achieve stable and efficient operation even when the apparent density of the material to be treated fluctuates. [Means for solving the problem]

[0012] That is, the method of operating the horizontal continuous conduction heat transfer dryer described in claim 1 is an apparatus in which a heat transfer member is provided inside a main shell, the heat transfer member is rotated while a heating medium is flowed inside the heat transfer member, an object to be treated is put into the main shell, and the object is retained in the main shell while coming into contact with the heat transfer member to obtain a dried product of the object to be treated, the total weight W of the object to be treated located in the main shell is reduced by the above-mentioned method. ITR The total weight of the retained products W ITR The present invention is characterized in that it optimizes either or both of the discharge rate F3 of the dried product from the main shell and the input rate F1 of the material to be treated into the main shell using the above.

[0013] In addition to the above requirements, the method of operating the horizontal continuous conduction heat transfer dryer according to claim 2 further includes the steps of: an apparent density ρ3 of the dried product discharged from the main shell; a total weight W of the retained product of the workpieces located in the main shell; ITR The retention rate H of the material retained in the main shell is calculated by the following formula (1) where H is the volume of the main shell, V is the volume of the main shell, and the discharge rate F3 of the dried product from the main shell is adjusted according to the deviation between this retention rate H and the target retention rate value Hs, the lower retention limit Hl, or the upper retention limit Hh.

[0014] [Number 1] H=W ITR / (ρ3×V)×100

[0015] The deviation here refers to the magnitude relationship between the residence rate H and the target residence rate Hs, the lower residence rate limit Hl, or the upper residence rate limit Hh.

[0016] The method of operating the horizontal continuous conduction heat transfer dryer according to claim 3 is, in addition to the requirements of claim 2, characterized in that the feed speed F1 of the material to be treated into the main shell is determined by the moisture content w1 of the material to be treated before being fed into the main shell, the moisture content w3 of the dried product discharged from the main shell, the retention time set value T0 of the material to be treated in the main shell, and the total weight W of the retained product. ITR It is characterized in that it is calculated by the following formula (2):

[0017] [Number 2] F1=(W ITR / T0) × (100-w3) / (100 -w1)

[0018] The method of operating a horizontal continuous conduction heat transfer dryer according to claim 4 further comprises, in addition to the requirements of claim 3, a deviation between a measured current I and a current setting value I0 flowing through a drive device that rotates the heat transfer member in the main body shell, And, The target retention rate Hs is changed based on the deviation between the moisture content w3 of the dried product and the set moisture content w30 of the dried product. The deviation here refers to the magnitude relationship between the current value I and the current setting value I0, and the magnitude relationship between the moisture content w3 of the dried product and the moisture content setting value w30 of the dried product.

[0019] The method of operating a horizontal continuous conduction heat transfer dryer according to claim 5 is characterized in that, in addition to the requirements of claim 3 or 4, the retention rate H, the feed rate F1 of the material to be treated, and the discharge rate F3 of the dried product can be changed based on variables consisting of a reference drying exhaust gas temperature t0 determined before operation, a drying exhaust gas temperature t during operation, and coefficients a, b, and c. The above problems are solved by the configurations of the inventions described in each of these claims. Effect of the Invention

[0020] First, according to the invention described in claim 1, the total weight W ITR By optimizing either or both of the discharge speed F3 of the dried product from the main shell and the input speed F1 of the material to be treated into the main shell using the above, the operating efficiency of the horizontal continuous conduction heat transfer dryer can be improved.

[0021] According to the invention described in claim 2, the retention rate H can be calculated using the apparent density ρ3 of the dried product discharged from the main shell, which can be easily measured, instead of the apparent density of the retained product located inside the main shell, and the dried product discharge rate F3 can be made appropriate.

[0022] According to the invention described in claim 3, the speed F1 of feeding the objects to be treated into the main shell is set to be equal to the total weight W ITR and can be set appropriately according to the moisture content w1 of the treated product and the moisture content w3 of the dried product.

[0023] According to the invention described in claim 4, the retention rate target value Hs can be set appropriately depending on the amount of retained products and the drying condition.

[0024] According to the invention described in claim 5, by making the equations for calculating the retention rate H, the feed rate F1 of the material to be treated, and the discharge rate F3 of the dried product include the exhaust temperature t, it is possible to calculate even more appropriate values. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a schematic diagram showing a control system for implementing the method for operating a horizontal continuous conduction heat transfer dryer of the present invention. [Diagram 2] FIG. 2 is a partially cutaway front view of a horizontal continuous conduction heat transfer dryer. [Diagram 3] 1A is a partially see-through left side view of a horizontal continuous conduction heat transfer dryer, and FIG. 1B is a partially cut-away right side view. [Figure 4]FIG. 2 is a skeletal diagram showing how the workpiece is discharged from the main body shell and how the apparent density is measured. [Diagram 5] 1 is a flowchart showing a method for operating the horizontal continuous conduction heat transfer dryer of the present invention. [Figure 6] 13 is a flowchart showing details of step S5 for changing the retention rate target value Hs. [Figure 7] FIG. 13 is a block diagram showing an embodiment in which the apparent density measuring device is installed in a different manner. [Figure 8] 1 is a graph showing the apparent density (|ρ2-ρ3| / ρ3) vs. operating time characteristics of the retained product located within the main shell and the dried product discharged from the main shell. [Figure 9] 1A and 1B are a front view and a side view, partly cut away, of an existing horizontal continuous conduction heat transfer dryer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The best mode of the method of operating the horizontal continuous conduction heat transfer dryer of the present invention is as shown in the following embodiment, but this embodiment can be modified as appropriate within the scope of the technical concept of the present invention. EXAMPLES

[0027] Hereinafter, the method of operating the horizontal continuous conduction heat transfer dryer of the present invention will be described in detail together with its operating mode after explaining the configuration of the horizontal continuous conduction heat transfer dryer 1. First, the horizontal continuous conduction heat transfer dryer 1 is an apparatus suitable for drying a material M to be treated that is in a muddy, cake-like, powdery or granular state, and is an apparatus for obtaining a dried product D by retaining the material M to be treated while evaporating volatile matters such as moisture contained therein. As shown in Figs. 1 to 3, this dryer is provided with a multi-tubular heating tube 11 in a main body shell 10 provided on a machine frame 100, and rotates this multi-tubular heating tube 11 while flowing steam as a heating medium therein, and dries the material M to be treated by bringing it into contact with the multi-tubular heating tube 11 while retaining it in the main body shell 10.

[0028] As shown in FIG. 3, the main body shell 10 is, for example, a hollow member having an oblong cross section, and is formed with an inlet 101, an overflow port 102, a carrier gas port 103, and an exhaust port 104. Here, the inlets 101 are formed at a plurality of locations on the upper portion of the main body shell 10. First, a first inlet 101a is formed near the exhaust port 104 formed at the upper left portion in FIG. 2. A second inlet 101b is formed at a portion closer to the center than the exhaust port 104, and a third inlet 101c is formed between the second inlet 101b and the carrier gas port 103 formed at the upper right portion in FIG. 2. In this embodiment, the inlets 101 are formed at three locations, but the inlets 101 may be formed at one, two, or four or more locations depending on the specifications of the horizontal continuous conduction heat transfer dryer 1. The location of the inlets 101 is not particularly limited, and the material M may be introduced from any location as long as it is possible to introduce the material M into the main body shell 10. Then, the material to be treated M is pumped by the material to be treated input device 6 equipped with, for example, a sludge pump, and distributed to each input port 101. The material to be treated input device 6 is driven by a motor 61, and the amount of the material to be treated M to be pumped (the amount of sludge, in detail, the input speed of the material to be treated, which will be described later) can be changed by changing the setting value of the frequency of an inverter connected to the motor 61.

[0029] The main body shell 10 and the multi-tube heating tube 11 are installed on the machine frame 100 in a horizontal state, or are installed on the machine frame 100 at an incline so that the exhaust port 104 side is somewhat higher than the carrier gas port 103 side. Furthermore, the main body shell 10 has a double jacket structure, and a steam passage is formed from a steam supply port 105 formed near the inlet 101a to a drain port 106 formed below the overflow port 102, so that the inside of the main body shell 10 can be heated. Note that instead of such a double jacket structure, a tracer pipe or the like can be installed.

[0030] The overflow port 102 is formed on the high side surface of the main body shell 10, and includes a fixed dam plate 107 and a dam plate 108 for covering a part of the overflow port 102. The fixed dam plate 107 is appropriately fixed by bolts (not shown) or the like so that there is a gap between the upper end and the lower end of the overflow port 102. Meanwhile, the dam plate 108 is provided on the rear side of the fixed dam plate 107, and is slid up and down via an appropriate link mechanism (not shown) using an air cylinder 109 as a driving source. In this embodiment, when the dam plate 108 is slid upward, the lower part of the fixed dam plate 107 is opened as shown in FIG. 4(b), and the dried product D overflows from this open part and is discharged from the main body shell 10. When the dam plate 108 is lowered by the air cylinder 109, the open part is blocked, and the discharge of the dried product D from the main body shell 10 is stopped as shown in FIG. 4(a). As shown in FIG. 1, the air cylinder 109 is driven by supplying or cutting off the compressed air by opening and closing an electromagnetic valve 109a. The opening and closing operation of the solenoid valve 109a is repeatedly and continuously performed during the drying operation in accordance with the set values ​​of the opening and closing times of the barrier plate 108, which will be described later. Further, a chute 12 is provided on the outside of the overflow port 102, the fixed dam plate 107 and the dam plate 108 so as to cover them, and a rotary valve 122 is provided at a dried product discharge port 121 formed in this chute 12.

[0031] The multi-tube heating tube 11 includes end plates 112 on both sides of a tube bundle 116 formed by arranging a plurality of tubes in a cylindrical shape, and a shaft body 113 at the center of the end plates 112, and the shaft body 113 is rotatably supported by a bearing block 114 provided on the machine frame 100. A motor 14 is provided on the machine frame 100 as a drive device for rotating the multi-tube heating tube 11. Rotary joints 115 (115a, 115b) are attached to both ends of the shaft body 113, and are connected to a tube bundle 116. A seal mechanism 13 is provided between the shaft body 113 and the main body shell 10 to block the outside air. The side periphery of the tube bundle 116 is provided with a number of angles 111 (12 in this embodiment) equipped with a number of lifters 117 and feed blades 118 at appropriate angles, which scoop up the material M to be treated and bring it into contact with each tube of the tube bundle 116 while proceeding from the inlet 101 side to the overflow outlet 102 side.

[0032] The bottom of the main shell 10 is equipped with a load cell 15, which measures the weight of the main shell 10 and determines the total weight of the objects M (hereinafter, the total weight of the objects W) located therein. ITR It is said that it is possible to measure mass (kg). The load cell 15 measures the total weight W ITR As long as it is possible to measure the above, the installation position is not limited to the lower part of the main body shell 10. Furthermore, the total weight of the retained goods W ITR The retention rate H [%] is calculated using the above formula. This retention rate H is calculated based on the main shell volume V [m 3 〕, and is calculated by the following formula (1). The main shell volume V here refers to a volume (fixed value) capable of being filled with the workpiece M, which is the internal volume of the main shell 10 minus the volume of internal parts such as the multi-tube heating tube 11 and the ventilation space for the passage of gas components such as the carrier gas and water vapor evaporated from the workpiece M. However, since what is important in the present invention is the rate of change of the retention rate H (variable value), the detailed definition of the main shell volume V is not limited to the one described above. H=W ITR / (ρ2×V)×100 · · Equation (1) ρ2 [kg / m 3 〕: Apparent density of the workpiece M located in the main body shell 10 (apparent density of retained workpiece) V〔m 3 〕: Main body shell volume

[0033] Although not shown, a steam generator is provided in addition to the horizontal continuous conduction heat transfer dryer 1, and a suitable device such as a U-shaped device, a straight tube type, a helical coil type, etc. A pipe is connected from this steam generator to the rotary joint 115a and the steam supply port 105 in the horizontal continuous conduction heat transfer dryer 1. A carrier gas is supplied into the main shell 10 through a carrier gas port 103. The volatile components volatilized from the workpiece M by the heating of the multi-tube heating tube 11 are carried away by the carrier gas through an exhaust port 104 to the outside of the main shell 10. Since the carrier gas contains not only the volatile components but also fine powder generated from the workpiece M, a dust removal device (not shown) may be provided on the path of the carrier gas flowing after the exhaust port 104. Furthermore, a temperature sensor 16 is provided on the path of the carrier gas flowing after the exhaust port 104.

[0034] As an example, an apparent density measuring device 2 is provided below the dried product discharge port 121 of the chute 12. As shown in Figures 1, 2 and 4, this device calculates the apparent density of the dried product D from the weight of the dried product D taken into the sampling container 21 and the volume of the sampling container 21, and is configured to include the sampling container 21 and a load cell 22 for measuring the weight of the sampling container 21. Further, a level meter 23 is provided for detecting that a predetermined amount of the dried product D has been put into the sampling container 21. Supply and stop of the supply of the dried product D to the sampling container 21 is performed by opening and closing a valve 24, and discharge and stop of the discharge of the dried product D from the sampling container 21 is performed by opening and closing a valve 25.

[0035] A flexible chute 26a is provided below the valve 24. The flexible chute 26a is, for example, a cylindrical chute made of thin silicone rubber, and guides the dried product D to the sampling container 21. Further, the valve 25 below the sampling container 21 is fastened to the sampling container 21 with a bolt or the like. A flexible chute 26b is provided below the valve 25. This flexible chute 26b is, for example, a cylindrical chute made of thin silicone rubber. These flexible chutes 26a, 26b are provided to prevent the dried product D from scattering around, and are also provided so as not to cause a large error in the weight measurement by the load cell 22.

[0036] In the configuration shown in Figures 1, 2, and 4, the apparent density measuring device 2 is integrally provided with the horizontal continuous conduction heat transfer dryer 1, and all the dried products D discharged from the main shell 10 pass through the apparent density measuring device 2, but a different installation form can also be adopted. Specifically, a configuration may be adopted in which an apparent density measuring device 2 is provided for a conveyor device provided at the next stage of the dried product discharge outlet 121.The configuration shown in Figure 7(a) has a discharge conveyor 4 provided at the next stage of the dried product discharge outlet 121, a dried sludge hopper 5 provided at the next stage of this discharge conveyor 4, and an apparent density measuring device 2 provided between the discharge conveyor 4 and the dried sludge hopper 5. 7(b) shows an embodiment in which two discharge conveyors 41 and 42 are disposed at the next stage of the dried product discharge outlet 121, a dried sludge hopper 5 is disposed at the next stage of the discharge conveyor 42, and an apparent density measuring device 2 is provided between the discharge conveyor 41 and the discharge conveyor 42. The discharge conveyor 41 has two discharge outlets 412 and 416, while the discharge conveyor 42 has two input ports 422 and 426, and the discharge outlet 412 and the input port 422, and the discharge outlet 416 and the input port 426 are opposed to each other. By disposing the apparent density measuring device 2 between the discharge outlet 416 and the input port 426, a part of the dried product D discharged from the main shell 10 can be extracted and measured.

[0037] Here, the measurement of apparent density by the apparent density measuring device 2 will be described. First, the volume of the dried product D when it reaches the sensing position of the level meter 23 is measured before operation, and this volume is input and stored as the "volume value" of the sampling container 21 in a programmable logic controller (hereinafter referred to as PLC) (not shown) of the control panel 3 before drying operation. Furthermore, the weight of the sampling container 21 without the dried product D therein is measured by the load cell 22, and is input to and stored in the PLC. During the drying operation, the weight of the sampling container 21 when a predetermined amount of the dried product D is placed therein is measured by the load cell 22 and input to the PLC. As a result, the apparent density ρ3 of the dried product D is calculated by the PLC from the volume value, the weight when no dried product D is placed therein, and the weight when a predetermined amount of the dried product D is placed therein.

[0038] The horizontal continuous conduction heat transfer dryer 1 and peripheral devices for carrying out the present invention are configured as described above as an example. Hereinafter, the operating mode of this device and the "method of operating the horizontal continuous conduction heat transfer dryer" of the present invention will be described with reference to the flowchart shown in FIG. 5. The feature of the "operation method of the horizontal continuous conduction heat transfer dryer" of the present invention is that the weight of the workpiece M located inside the main shell 10 (the total weight of the retained workpiece W ITR ) and measure the total weight of the retained products W ITR Using the above, either the discharge rate F3 of the dried product from the main shell 10 or the input rate F1 of the material to be treated into the main shell 10 is optimized, or both.

[0039] (1) Preparing the dryer First, prior to the input of the workpiece M, the multi-tubular heating tube 11 and the main body shell 10 in the horizontal continuous conduction heat transfer dryer 1 are heated, and the motor 14 is started to rotate the multi-tubular heating tube 11, and heating steam (for example, 0.5 MPa (about 160°C)) is supplied to the rotary joint 115a and the steam supply port 105. The heating steam supplied to the rotary joint 115a increases the temperature of the multi-tubular heating tube 11 while passing through the tube bundle 116, and eventually becomes drain and is discharged to the outside from the rotary joint 115b on the other end side. The heating steam supplied to the steam supply port 105 increases the temperature of the main body shell 10, and eventually becomes drain and is discharged to the outside from the drain port 106. A siphon pipe (not shown) is provided inside end plate 112 on the rotary joint 115b side, and a steam trap (not shown) is provided in the path through which the drain discharged from rotary joint 115b flows. Also, a steam trap (not shown) is provided in the path through which the drain discharged from drain port 106 flows.

[0040] (2) Drying of the workpiece Next, the material to be treated M is put into the inlet 101, and this material is moved from the inlet 101 side to the overflow outlet 102 side by the action of the feed blade 118, and is further lifted up by the lifter 117 to come into contact with the tube bundle 116, etc., at which time, it receives heat and progresses in drying. At this time, since the inlets 101 are formed at a plurality of places along the longitudinal direction of the multi-tubular heating tube 11, the heat conduction surface of the multi-tubular heating tube 11 can be effectively used, and the drying efficiency is improved. Then, as shown in FIG. 4(b), when the dam plate 108 is raised and the lower part of the fixed dam plate 107 is released, the dried product D flows out from the overflow outlet 102 and is sent to the apparent density measuring device 2 side via the chute 12. The discharge speed of the dried product D is adjusted by varying the opening and closing time of the overflow outlet 102 by raising and lowering the dam plate 108. Examples include a pattern of repeatedly opening for 2 seconds and closing for 28 seconds, or a pattern of repeatedly opening for 2 seconds and closing for 18 seconds. If the closing time of the overflow port 102 is short, the dry product discharge speed F3 (discharge amount increases), which will be described in detail later, will be high, whereas if the closing time is long, the dry product discharge speed F3 will be low (discharge amount decreases).

[0041] As described above, when a series of operations such as feeding the workpiece M into the horizontal continuous conduction heat transfer dryer 1 and discharging the dried product D from the horizontal continuous conduction heat transfer dryer 1 is established, the "operation method of the horizontal continuous conduction heat transfer dryer" of the present invention is carried out (see Figure 5). First, in step S0, a timer is started. The PLC of the control panel 3 is preset with a residence time setting value T0, a moisture content setting value w30 of the dried product, and a current setting value I0. Furthermore, provisional setting values ​​are preset for the feed rate F1 of the workpiece and the discharge rate F3 of the dried product. For a predetermined time from the start (i.e., the time until the first step S12), operation is performed using these setting values, and during this time these are used for the measurements described below and for the control values ​​of the second and subsequent loops. In this embodiment, as an example, the residence time setting value T0 is set to 10 [h], the dried product moisture content setting value w30 is set to 15 [WB%], and the current setting value I0 is set to 15 [A]. Furthermore, in step S11, the apparent density ρ3 of the dried product is measured by the apparent density measuring device 2, the moisture content w1 of the treated product is measured by the moisture sensor 17, the moisture content w3 of the dried product is measured by the moisture sensor 18, and the motor current value I is measured by an ammeter not shown, and these values ​​are input into the PLC of the control panel 3.

[0042] Although the apparent density ρ3 of the dried product is measured every six hours as an example, it may be measured every time a predetermined amount of the dried product D is placed in the sampling container 21. The moisture content w1 of the treated material is measured, for example, every hour, by a moisture sensor 17 provided in the input path, and the moisture content w3 of the dried product is measured, for example, every 30 minutes, by a moisture sensor 18 provided in the discharge path. The frequency of these measurements can be set arbitrarily, and the average value of the data obtained from the start of measurement in step S11 to step S12 is determined in S13, and these average values ​​(ρ3, w1, w3, I) are used in the next loop.

[0043] Next, in step S2, the total weight of the retained products W ITR is measured by the load cell 15 and this value is input to the PLC of the control panel 3.

[0044] In the second and subsequent loops, in step S3, the retention rate H is calculated by the following formula (1'), and this value is input to the PLC of the control panel 3. H=W ITR / (ρ 3×V)×100 (Equation 1′) In equation (1'), the value of the apparent density ρ2 of the retained products in the main shell 10 should normally be used. However, the retained products in the main shell 10 are not physically separated by classification or the like, and are always periodically removed as dried products from a designated overflow port 102. Therefore, the relationship between the apparent density ρ2 of the retained products and the apparent density ρ3 of the dried products can be regarded as ρ2 ≒ ρ3 (ρ2 = ρ3 + α). In addition, since the purpose of this control is to grasp the change in the retention rate H over time, the value of the apparent density ρ3 of the dried products can be used.

[0045] (3) Optimization of discharge speed of dried products Next, the dried product discharge speed F3 is optimized based on the deviation between the measured current I flowing through the motor 14, which is the drive device that rotates the multi-tube heating tube 11, which is the heat transfer member inside the main shell 10, and the set current value I0, and the deviation between the measured dried product moisture value w3 and the set dried product moisture value w0. Specifically, first, in step S4, it is determined whether the retention rate H is an appropriate value. Here, as an example of the appropriate value, the retention rate H is within a range between the retention rate lower limit Hl and the retention rate upper limit Hh (retention rate lower limit Hl≦retention rate H≦retention rate upper limit Hh). In this embodiment, the retention rate lower limit Hl is set to 35% and the retention rate upper limit Hh is set to 65%.

[0046] If the determination in step S4 is YES, the process proceeds to step S5, whereas if the determination is NO, the process proceeds to step S8. First, in step S5, the retention rate target value Hs is determined (see FIG. 6). First, in step S51, it is determined whether or not the measured moisture content w3 of the dried product is higher than the set moisture content w30 of the dried product. If the determination in step S51 is YES, the process proceeds to step S52, whereas if the determination is NO, the process proceeds to step S53. In these steps S52 and S53, a determination is made as to whether the measured current value I is higher than the current setting value I0. In step S54, if the determination in step S52 is YES, the retention ratio target value Hs is changed to 60%. On the other hand, if the determination in step S52 is NO, the retention ratio target value Hs is changed to 55%. If the determination in step S53 is YES, the retention rate target value Hs is changed to 45%. On the other hand, if the determination is NO, the retention rate target value Hs is changed to 40%. Although step S54 has been exemplified with specific numerical values ​​in this manner, deviations from the retention rate target value Hs may also be set and changed.

[0047] Next, in step S6, it is determined whether the retention rate H is equal to or greater than the retention rate target value Hs. In step S7, if the determination in step S6 is YES, the discharge speed F3 of the dried product is changed to a value calculated by the following formula (2). On the other hand, if the determination is NO, the discharge speed F3 of the dried product is changed to a value calculated by the following formula (3). F3=(W ITR / T0)×1.5 Equation (2) F3=(W ITR / T0)×0.75 Equation (3)

[0048] On the other hand, if the determination in step S4 is NO and the process proceeds to step S8, it is determined whether the residence rate H is greater than the residence rate upper limit Hh. In step S9, if the determination in step S8 is YES, the discharge speed F3 of the dried product is changed to a value calculated by the following formula (4). On the other hand, if the determination is NO (if Hl>H), the discharge speed F3 of the dried product is changed to a value calculated by the following formula (5). F3=(W ITR / T0)×2.0 Equation (4) F3=(W ITR / T0)×0.5 Equation (5) The values ​​(0.5, 0.75, 1.5, 2.0) in formulas (2) to (5) were obtained from test runs conducted under various conditions in advance. These are coefficients for F0 and can be changed as appropriate depending on the situation at the site.

[0049] (4) Optimization of the feed rate of the material to be treated Furthermore, in the "operating method of a horizontal continuous conduction heat transfer dryer" of the present invention, the input speed F1 of the workpiece is also optimized, and following step S2, in step S10, the speed F1 is changed to a value calculated by the following equation (6). F1=(W ITR / T0)×((100-w3) / (100-w1)) Equation (6) =F0×(100-w3) / (100 -w1) F0=(W ITR / T0)

[0050] Then, when it is confirmed in step S12 that a predetermined time has elapsed, the average values ​​of the apparent density ρ3 of the dried product, the moisture content w1 of the treated product, the moisture content w3 of the dried product, and the measured current I are determined in step S13, and the process returns to steps S2 and S11 to repeat the above-mentioned operations. The predetermined time here is a value obtained in advance through test operations carried out under various conditions, and in this embodiment, it is set to 6 hours as an example.

[0051] As described above, according to the present invention, when the horizontal continuous conduction heat transfer dryer 1 is operated, the total weight W ITR The total weight of the retained products W ITR Therefore, by optimizing either or both of the discharge rate F3 of the dried product from the main shell 10 or the input rate F1 of the material to be treated into the main shell 10, it is possible to achieve stable and efficient operation even when the apparent density of the material to be treated M fluctuates and the volume of the retained material also fluctuates. In particular, this control not only adjusts the discharge speed F3 of the dried product depending on whether the retention rate H of the material M in the horizontal continuous conduction heat transfer dryer 1 exceeds the retention rate lower limit Hl or upper limit Hh, but also adjusts the retention rate target value Hs during operation by comparing the moisture content w3 of the dried product and the measured current I with the respective settings when the retention rate lower limit Hl and the retention rate upper limit Hh are in the appropriate range. This is an especially effective means in a system in which the horizontal continuous conduction heat transfer dryer 1 is operated so that the difference between the retention rate apparent density ρ2 and the dried product apparent density ρ3 in the dryer is maintained at a small density of within 10%. The difference referred to here is calculated using the following equation (7). (|ρ2-ρ3| / ρ3)×100 (Equation 7)

[0052] Here, the reason for using the value of the apparent density ρ3 of the dried product in place of the value of the apparent density ρ2 of the retained product in the main body shell 10 when calculating the retention rate H in step S3 will be described. The graph shown in FIG. 8 shows the actual measured value-time characteristics of the retained product apparent density ρ2 and the dried product apparent density ρ3 measured using the verification treatment object M. From the measurement results, the average value of ρ3-ρ2 is about 13 kg / m 3 This value can be read from the graph over roughly the entire time axis. ρ2=ρ3-13〔kg / m 3 〕 Based on this result, for example, let us set ρ2 = 325 and ρ3 = 325 + 13 = 338, and calculate the retention rates H2 and H3. We then find the difference between the two and calculate how this value compares to H2. H2=W ITR ÷(ρ2×V)×100 H3=W ITR ÷(ρ3×V)×100 Therefore, |H3−H2| / H2= |ρ2−ρ3| / ρ3×100=3.8 The difference between the two is extremely small, at around 3.8% for H2. Therefore, the value of H calculated using ρ3 instead of ρ2 can be regarded as the value calculated using ρ2.

[0053] Next, an embodiment in which temperature conditions are taken into consideration will be described. The retention rate H, the feed rate F1 of the material to be treated, and the discharge rate F3 of the dried product may be calculated from an equation in which the dried exhaust gas temperature t detected by the temperature sensor 16 is taken into consideration. In other words, an increase in the value of the dried exhaust gas temperature t means that the exposed area of ​​the heat transfer surface of the tube bundle 116 has increased, which means that the apparent density ρ2 of the retained product has increased, which in turn means that the retention rate H has decreased, meaning that an operation is required to increase the input speed F1 of the treated material or to decrease the discharge speed F3 of the dried product. On the other hand, a decrease in the value of the dried exhaust gas temperature t means that the exposed area of ​​the heat transfer surface of the tube bundle 116 has decreased, which means that the apparent density ρ2 of the retained product has decreased, which in turn means that the retention rate H has increased, meaning that an operation is required to reduce the input speed F1 of the treated material or an operation to increase the discharge speed F3 of the dried product.

[0054] Taking these temperature conditions into consideration, the equations for calculating the retention rate H, the input speed F1 of the material to be treated, and the discharge speed F3 of the dried product are as shown below. H=(W ITR / (ρ3×V))×(t+a×t0) / t×100... Formula (1′′) F1=((W ITR / T0)×(100-w3) / (100-w1))×(t+b×t0) / t...Equation (2′) F3=(W ITR / T0)×(t+c×t0) / t...Equation (8) t0: Reference dry exhaust gas temperature t: Dry exhaust gas temperature a: constant b: constant c: constant In order to quickly respond to a sudden change in the retained goods apparent density ρ3, the above constants a, b, and c take different values ​​according to the rate of change of ρ3, as shown in Table 1 below.

[0055] [Table 1]

[0056] In this way, by making the equations for calculating the residence rate H, the feed rate F1 of the material to be treated, and the discharge rate F3 of the dried product include the exhaust temperature t, it is possible to obtain more appropriate values. [Explanation of symbols]

[0057] 1. Horizontal continuous conduction heat transfer dryer 10 Body shell 100 machines 101 Inlet 101a Inlet 101b Inlet 101c Inlet 102 Overflow outlet 103 Carrier gas port 104 Exhaust port 105 Steam supply port 106 Drain port 107 Fixed weir plate 108 Weir plate 109 Air Cylinder 109a Solenoid valve 11 Multi-tube heating tube 111 Angle 112 Headboard 113 Axial body 114 Bearing block 115 Rotary joint 115a rotary joint 115b rotary joint 116 Tube bundle 117 Lifter 118 Feather 12 SHOTS 121 Dry product outlet 122 Rotary Valve 13 Sealing mechanism 14 Motor 15 Load Cell 16 Temperature Sensor 17 Moisture Sensor 18 Moisture Sensor 2. Apparent density measuring device 21 Sampling Container 22 Load Cell 23 Level Gauge 24 Valve 25 Valve 26a Flexible Chute 26b Flexible Shot 3. Control Panel 4. Discharge Conveyor 41 Discharge conveyor 412 Outlet 416 Outlet 42 Discharge conveyor 422 Inlet 426 Inlet 5 Dry sludge hopper 6. Material input device 61 Motor D Dry product M Processing object

Claims

1. A device for producing a dried product of a material to be treated, comprising: a heat transfer member provided inside a main shell; the heat transfer member is rotated while a heating medium is flowing inside the heat transfer member; a material to be treated is placed inside the main shell; and the material is brought into contact with the heat transfer member while remaining inside the main shell, The total weight W of the object to be treated located within the main body shell ITR Measure The total weight of the retained goods W ITR Using A method for operating a horizontal continuous conduction heat transfer dryer, characterized in that either or both of a discharge rate F3 of a dried product from a main shell and a feed rate F1 of a material to be treated into the main shell are optimized.

2. The apparent density ρ3 of the dried product discharged from the main body shell; The total weight W of the object to be treated located within the main body shell ITR , Body shell volume V The retention rate H of the workpiece retained in the main body shell is calculated by the following formula (1): Depending on the deviation between this retention rate H and the retention rate target value Hs, the retention lower limit Hl, or the retention upper limit Hh, 2. A method for operating a horizontal continuous conduction heat transfer dryer according to claim 1, further comprising the step of adjusting a discharge speed F3 of the dried product from the main body shell. [Equation 1] H=W ITR / (ρ 3×V)×100

3. The feed speed F1 of the material to be treated into the main body shell is Moisture content of the material to be treated before being put into the main body shell w1, Moisture content of dried product discharged from the main body shell w3, A residence time setting value T0 of the workpiece in the main body shell; The total weight W ITR 2. The method for operating a horizontal continuous conduction heat transfer dryer according to claim 1, wherein the calculation is performed by the following formula (2): [Equation 2] <h2 style=";text-align:left;direction:ltr">1 = 1<h2 style=";text-align:left;direction:ltr"> ITR <h2 style=";text-align:left;direction:ltr"> (100) x (100) x (100)

4. A deviation between a measured current I and a set current I0 flowing through a drive device that rotates the heat transfer member in the main body shell. And, Based on the deviation between the dried product moisture content w3 and the dried product moisture content set value w30, 4. The method for continuous rotation of a horizontal continuous conduction heat transfer dryer according to claim 3, wherein the target residence rate Hs is changed.

5. The retention rate H, processing material input speed F1, and dry product discharge speed F3 are A reference dry exhaust gas temperature t0 determined before operation, Dry exhaust gas temperature during operation t; and the variables consisting of coefficients a, b, and c 5. The method for continuous rotation of a horizontal continuous conduction heat transfer dryer according to claim 4, wherein the change can be made based on the above.

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