JP5696948B2 - Conductive heat transfer dryer - Google Patents

Description

  The present invention relates to a conductive heat transfer type drying apparatus that dries a raw material in a paste, gel, or liquid state by conductive heating and separates and recovers the raw material in a solvent and a solid content.

  When a solvent and a solid resin are to be recovered from a paste, gel, or liquid raw material by dissolving the resin with a solvent, a drying apparatus that indirectly heats the raw material by conductive heating is often used. . In such a conduction heat transfer type drying apparatus, a pair of screws penetrating in the longitudinal direction of the casing is attached to a long casing before and after the raw material is supplied so as to mesh with each other, and the screws are made hollow or outside the casing. A biaxial meshing screw type that evaporates the solvent in the raw material while transferring the raw material by providing a jacket, passing a heat medium through these members, and rotating both screws in opposite directions. There is something.

  By the way, in the above-described two-shaft screw type conduction heat transfer type drying apparatus, when the supply amount of the raw material increases or the ratio of the solvent in the raw material increases, a part of the solvent does not evaporate. There was a problem of being discharged together with the solid content. This is because the raw material that has been dried to some extent moves along the lower part of the casing, and heat transfer from the screw is reduced, so if the operating conditions become severe, the raw material stays in the casing unless the processing capacity is reduced. This is because there are many cases where the solvent cannot be sufficiently evaporated during the operation.

  Further, when the raw material undergoes a phase change of liquid → viscous material → solid matter, the solid content generated from the raw material may be discharged in a flake state containing a solvent. Since the internal vapor pressure of flake solids is higher than that of the outside, the internal equilibrium vapor pressure temperature is also high, the encapsulated solvent is difficult to vaporize, and the drying efficiency during the reduced rate drying period is significantly reduced. Because it does.

  On the other hand, in Patent Document 1, a dam plate extending along the inner surface of the casing in a direction orthogonal to each screw is provided in front of the discharge port opened at the discharge side bottom of the casing, and the supply side surface of the dam plate Stirring claws adjacent to each screw are installed on each screw to extend the residence time of the raw material in the casing with the weir plate and increase the amount of residence, and while stirring the raw material with the stirring claw, the solid content exceeding the weir plate is discharged sequentially. Thus, it has been proposed to improve the drying efficiency.

JP 2011-206963 A

  However, in the conduction heat transfer type drying apparatus described in the above-mentioned Patent Document 1, the weir plate before the discharge port is orthogonal to each screw, so that it is at least between the shaft portion of the screw so as not to hinder the rotation of the screw. In addition, it is necessary to provide a gap in the inner wall of the casing, and the raw material is blocked by contact with the inner surface of the bottom of the casing, so that the vertical position cannot be changed. For this reason, it is difficult to adjust the residence time and residence amount of the raw material in the casing even if the operation conditions such as the type and throughput of the raw material change, and depending on the operation conditions, high drying efficiency is not necessarily obtained. There's a problem.

  Accordingly, an object of the present invention is to make it possible to easily adjust the residence time and residence amount of the raw material in the casing in accordance with the operating conditions in the twin-shaft screw type heat conduction type drying apparatus. .

  In order to solve the above problems, the present invention provides a pair of rotations penetrating the casing in the longitudinal direction in a longitudinal casing having a supply port on one end side in the longitudinal direction and a discharge port on the other end side. The shafts are mounted in parallel to each other, and screw portions that engage with each other are provided at portions that fit within the casings of the two rotary shafts, and the rotary shafts are driven to rotate in opposite directions to be supplied from the supply port of the casing. In a conductive heat transfer type drying apparatus that dries the raw material by conductive heating while transferring the raw material to the other end side of the casing by the screw portion of each rotating shaft, the other end side of each rotating shaft is adjacent to the screw portion. Providing a stirring portion for stirring the raw material without transferring it in the axial direction, and opening the outlet of the casing to a position facing the stirring portion of each rotating shaft on both the left and right sides of the casing; The weir plate for closing the lower portion of the opening of the outlet of these was adopted adjustable in position provided a configuration in the vertical direction.

  That is, at the position facing the non-feed agitating part provided adjacent to the screw part of each rotating shaft, the outlet of the casing is opened on both the left and right sides of the casing, and the rotating shaft and casing are placed at the opening of each outlet. By providing a weir plate whose position can be adjusted in the vertical direction without interfering with the inner surface, it is possible to sequentially discharge the solid content exceeding the weir plate while promoting the drying of the raw material in the stirring unit, and the weir plate in the vertical direction. By adjusting the position and changing the height, the residence time and residence amount of the raw material in the casing can be easily adjusted.

  In the above configuration, an air supply port is provided in the upper part on the other end side of the casing, and the raw material that forms the top of the raw material layer staying in the vicinity of the stirring unit of each rotary shaft by the gas injected from the air supply port. By returning to one end side of the casing, the residence time of the raw material can be further extended with respect to a certain barrier plate height, and the raw material that has run on the preceding raw material layer when being sent from the screw part to the stirring part It can prevent being discharged in an insufficiently dry state.

  As described above, the conduction heat transfer type drying apparatus of the present invention opens the outlet of the casing at a position facing the stirring portion of each rotating shaft on both the left and right sides of the casing, and is positioned vertically in the opening of each outlet. Since an adjustable weir plate is provided, the residence time and amount of the raw material in the casing can be easily adjusted by adjusting the position of the weir plate in the vertical direction. Therefore, even if operating conditions such as the type of raw material and the amount of processing change, high drying efficiency can be reliably obtained without reducing the processing capacity.

Longitudinal front view of the conduction heat transfer type drying apparatus of the embodiment Sectional view along the line II-II in FIG. Transverse plan view of the discharge end side of FIG. a is a plan view of a modification of the stirring unit, b is a cross-sectional view taken along line IVb-IVb of a a is a plan view of another modification of the stirring unit, and b is a cross-sectional view taken along line Vb-Vb Explanatory drawing of the circulation path of the carrier gas of the drying apparatus of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This conductive heat transfer type drying device is for recovering a solvent and a solid resin from a paste, gel or liquid raw material by dissolving the resin with a solvent. As shown in FIGS. A long casing 1, a jacket 2 provided outside the casing 1, and a pair of rotating shafts 3 and 3 penetrating the casing 1 in the longitudinal direction are provided.

  The casing 1 includes a bowl-shaped main body 1a to which the rotary shaft 3 is attached and a cover 1b that covers the upper portion thereof, and a raw material supply port 4 is provided at a lower portion on one end side in the longitudinal direction of the main body 1a. Solid resin outlets 5 and 5 are provided on the left and right sides of the other end. On the other hand, an exhaust port 6 is provided in the upper part on one end side in the longitudinal direction of the cover portion 1b, and an air supply port 7 is provided in the upper part on the other end side, and the solvent evaporated from the raw material is blown from the air supply port 7. The gas (carrier gas) is discharged from the exhaust port 6 and collected. The air supply port 7 is configured to inject a carrier gas obliquely downward from the other end side of the discharge ports 5 and 5 toward the raw material layer near the discharge ports 5 and 5. Further, baffle plates 8a and 8b for changing the direction of the flow of the carrier gas from the air supply port 7 to the exhaust port 6 are provided on the inner surface of the cover portion 1b.

  The rotary shafts 3 are arranged in parallel to each other and are rotatably supported at both longitudinal ends of the main body 1a of the casing 1. A motor (not shown) is connected to the projecting portion from one end of the casing 1 so as to be driven to rotate in opposite directions.

  A hollow screw portion 9 for transferring the raw material to the other end side from one end portion in the longitudinal direction to the center portion is provided at a portion of each rotating shaft 3 that fits in the casing 1. And the stirring part 10 which stirs a raw material without transferring it to an axial direction in the site | part adjacent to this screw part 9 is provided, and feeds a raw material back to the site | part adjacent to the other end side of the stirring part 10. A reverse feed screw portion 11 that facilitates discharge from each discharge port 5 of the casing 1 is provided. The stirring unit 10 and the reverse feed screw unit 11 are each formed by fitting a cylindrical body having a stirring claw or a spiral blade formed on the outer periphery into a solid small diameter portion formed on the other end side of the rotating shaft 3. The stirring claws 10a of the stirring unit 10 have a radial cross section formed in a substantially triangular shape, and six are provided at equal intervals in the circumferential direction at two locations in the axial direction. Moreover, the screw part 9, the stirring part 10, and the reverse feed screw part 11 respectively mesh with those provided on the counterpart rotary shaft 3 so that a self-cleaning function can be obtained.

  And in the axial direction which faces the stirring part 10 of each rotating shaft 3, each discharge port 5 of the said casing 1 is opening in the rectangular shape, and the lower part of the opening part 5a of these each discharge port 5 is plugged up. A rectangular dam plate 12 is attached to the outer surface of the casing 1 with bolts 13 so that the position can be adjusted in the vertical direction.

  Next, the operation of this conductive heat transfer type drying apparatus will be described. First, when the raw material is supplied from the supply port 4 of the casing 1 in a state where both the rotary shafts 3 and 3 are rotated in opposite directions, the supplied raw material is supplied to the casing 1 by the screw portion 9 of each rotary shaft 3. It is transferred to the end side. At this time, heat is indirectly conducted from the heating medium such as water vapor passed through the inside of the jacket 2 and the screw portion 9 of each rotary shaft 3 to the raw material, and the solvent in the raw material is vaporized, whereby the raw material is dried. To go. The evaporated solvent is discharged from the exhaust port 6 together with the carrier gas blown from the air supply port 7.

  Here, as described above, the baffle plates 8a and 8b for changing the direction of the flow of the carrier gas from the air supply port 7 to the exhaust port 6 are provided in the upper part of the casing 1, so Drying by liquid contact is also performed efficiently.

  The raw material mainly composed of solid resin is transferred to the stirring unit 10 by the screw unit 9 of each rotating shaft 3 and is stirred by the stirring unit 10 without being transferred in the axial direction. At this time, since the raw material transferred in the flake state is also pulverized and refined by the stirring claw 10a of the stirring unit 10, the evaporation of the solvent contained in the raw material is promoted, and the drying efficiency is improved. Moreover, the raw material extruded to the other end side from the stirring part 10 by the subsequent raw material is returned to the stirring part 10 by the reverse feed screw part 11 and stirred again.

  And the raw material stirred by the stirring part 10 of each rotating shaft 3 is once dammed up by the weir plate 12 provided in the opening part 5a of the discharge port 5 of the right and left sides of the casing 1, Then, it sequentially reaches the stirring claw 10a. It is wound up, gets over the barrier plate 12, and is discharged from the discharge port 5 as a solid resin.

  Here, depending on the operating conditions, the raw material that has not been sufficiently dried due to being in a flake state or the like in the screw portion 9 may ride on the preceding raw material layer when being sent to the stirring portion 10, but the vicinity of the stirring portion 10 Since the raw material forming the top of the raw material layer staying in the chamber is returned to one end side of the casing 1 (to the screw portion 9) by the carrier gas injected from the air supply port 7 of the casing 1, There is little risk of being discharged.

  This two-shaft engagement screw type heat transfer type drying device has the above-described configuration, and the discharge ports 5 and 5 are opened at positions facing the stirring section 10 of each rotary shaft 3 on both the left and right sides of the casing 1. Since the dam plate 12 whose position can be adjusted in the vertical direction is provided in the opening 5a of each discharge port 5, even when the operating conditions such as the type of raw material and the processing amount change, the vertical position ( By changing the height), the residence time and residence amount of the raw material in the casing 1 can be easily adjusted, and high drying efficiency can be obtained without reducing the processing capacity.

  Further, since the raw material forming the top of the raw material layer near the stirring unit 10 is returned to the one end side of the casing 1 by the carrier gas injected from the air supply port 7 of the casing 1, drying is performed as described above. However, it is possible to prevent the raw material from being discharged insufficiently, and to further extend the residence time of the raw material with respect to a certain height of the weir plate 12.

  In the above-described embodiment, the stirrer 10 of each rotating shaft 3 has a stirring claw 10a having a substantially triangular cross section having a raw material stirring function and a crushing function, but the shape of the stirring claw is limited to this. For example, those shown in FIGS. 4 and 5 can be employed.

  Among these, the example shown in FIGS. 4A and 4B employs a pin-shaped stirring claw 10b with an emphasis on the pulverizing function of the raw material, and the pin-shaped stirring claw 10b has one stirring unit 10. Are provided at three positions in the axial direction, and at the other stirrer 10 at four positions in the axial direction at eight equal intervals in the circumferential direction.

  On the other hand, in the example shown in FIGS. 5 (a) and 5 (b), four stirring claws 10 c having a T shape in plan view are provided in one stirring unit 10 at equal intervals in the circumferential direction, and the other stirring unit 10 is provided with the other stirring unit 10. Is provided with six pairs of L-shaped stirring claws 10d in plan view that mesh with one T-shaped stirring claw 10c of one stirring unit 10 at equal intervals in the circumferential direction to improve the stirring function. .

FIG. 6 shows the circulation path of the carrier gas used in the above-described embodiment. The carrier gas blown from the air supply port 7 of the casing 1 is discharged from the exhaust port 6 together with the vaporized solvent as described above. At this time, the exhaust gas composed of the carrier gas and the vaporized solvent is often mixed with a powdery resin generated from the raw material. Therefore, the exhaust gas discharged from the exhaust port 6 is first passed through the bag filter 14 to remove the resin powder. The resin powder collected by the bag filter 14 is returned to the casing 1, and the exhaust gas from which the resin powder has been removed is sent to the heat exchanger 15. Part of the exhaust gas subjected to the heat exchange operation is sent to a solvent recovery processing device (not shown) outside the system, and the other is mixed with new carrier gas sent from the carrier gas supply source 16 to reduce the humidity. Then, the air is again blown from the air supply port 7 as the carrier gas.

  By circulating the carrier gas through the above-mentioned route, not only the amount of carrier gas used can be reduced, but also the drying capacity can be adjusted by changing the amount of exhaust gas sent out of the system or the amount of carrier gas newly mixed. .

DESCRIPTION OF SYMBOLS 1 Casing 2 Jacket 3 Rotating shaft 4 Supply port 5 Discharge port 5a Opening part 6 Exhaust port 7 Supply port 8a, 8b Baffle plate 9 Screw part 10 Stirring part 10a, 10b, 10c, 10d Stirring claw 11 Reverse feed screw part 12 Weir Board

Claims (2)

A pair of rotary shafts penetrating the casing in the longitudinal direction are attached in parallel to each other in a longitudinally long casing having a supply port on one end side in the longitudinal direction and a discharge port on the other end side. A screw part that meshes with each other in a portion that fits in the casing is provided, and both the rotation shafts are driven to rotate in opposite directions and downward on opposite sides , whereby the raw material supplied from the supply port of the casing is In a conduction heat transfer type drying apparatus that is dried by conduction heating while being transferred to the other end side of the casing at the screw portion of each rotating shaft, the raw material is pivoted adjacent to the screw portion on the other end side of each rotating shaft. A stirring portion for stirring without being transferred in the direction is provided, and the discharge ports of the casing are opened on the left and right sides of the casing at positions facing the stirring portions of the rotary shafts. Conductive heat transfer-type drying apparatus, wherein a barrier plate is provided so as to be position adjustment in the vertical direction for closing the lower portion of the opening of each outlet.   An air supply port is provided in the upper part on the other end side of the casing, and the raw material forming the top of the raw material layer staying in the vicinity of the stirring portion of each rotating shaft is returned to the one end side of the casing by the gas injected from the air supply port. The conduction heat transfer type drying apparatus according to claim 1, wherein the apparatus is configured as described above.

Images