JP2016109304A - Rotation dryer with indirect heating pipe and dry method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve utilization efficiency of a heating medium, and enhance drying capacity.SOLUTION: A condensate liquid chamber 30 with which end part openings of heating pipes 11, 11, ... communicate is formed at the end part of a rotary cylinder 10. Formed is a plurality of header chambers 31, 31, ... that are positioned radially outward with respect to the condensate liquid chamber 30, communicate with the condensate liquid chamber 30, and are separated from each other in a circumferential direction. The condensate liquid chamber 30 and the header chamber 31 communicate with each other, the header chamber 31 and a discharge passage 34 are connected to each other with a header pipe 33, and condensate liquid of a heating medium is guided from the header chamber 31 to the discharge passage 34 through the header pipe 33.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotary dryer with an indirect heating tube and a drying method, and in particular, while rotating a rotating cylinder around its central axis, the material to be dried supplied to one end thereof is moved to the other end. With an indirect heating tube that supplies a heating medium to a number of heating tubes arranged in the rotating cylinder, contacts the moving object to be dried with this heating tube, and then discharges it from the other side of the rotating cylinder The present invention relates to a rotary dryer and a drying method.

  A rotary dryer with an indirect heating tube, typically represented by a steam tube dryer, is characterized by a large heating area per volume, and therefore a large drying capacity and a high heat transfer rate.

  Furthermore, since the heating medium and the object to be dried are not in direct contact, the object to be dried is not mixed in the heating medium, no processing equipment for separating the object to be dried in the heating medium is required, and the operation is easy. It is widely used in the chemical industry, food industry, steel industry, etc., and has many achievements for drying terephthalic acid, synthetic resin, soda ash, fertilizer, corn products, coal and the like.

  This dryer usually has a length of 10 to 30 m, and in a rotating cylinder, the wet powder or granular material is brought into contact with a heating tube heated by a circulating heating medium such as steam or heated air, and rotated. As the tube rotates, it is continuously dried while being moved to the discharge port. A heating medium for heating the heating tube is supplied to the heating tube via the rotary joint, and heat is supplied to the wet powder through the heating tube to dry the wet powder. The heating medium itself condenses in the heating tube to become a condensate, flows countercurrently to the heating medium along the gradient of the dryer, and is discharged from one end of the rotating cylinder.

  A conventional dryer will be described with reference to FIG. In the conventional dryer, the heating medium S is supplied from the pipe 81 to the inside of the dryer through a rotary joint. The condensate chamber 30 is provided with a pipe 33A that penetrates the inner wall 30i and communicates with the pipe 81, and the heating medium S is supplied to the condensate chamber 30 through the pipe 33A and supplied into each heating pipe 11. The heating tube 11 is heated. The heating medium S that has heated the inside of the heating tube 11 becomes the condensate D and flows down below the condensate chamber 30. The condensate D that has flowed down passes through the header pipe 33 </ b> B connected to the inner wall 30 i of the condensate liquid chamber 30 and is discharged from the discharge path 34 to the outside through the pipe 80.

  Examples of the condensate discharge mode include Patent Document 1 and Patent Document 2.

Japanese Patent No. 3894499 Japanese Patent Publication No.42-8110

  However, in the conventional rotary dryer with an indirect heating tube, in order to move the dried product toward the dried product discharge portion of the rotary cylinder and discharge it, the rotary cylinder 10 also has a factor of being arranged in a downward slope, 10 is formed at the end in the axial direction, and the condensate tends to stay in the condensate chamber 30 where the end openings of the heating tubes 11, 11... Communicate with each other. Since the heating medium does not circulate for the groups 11, 11,..., The heat transfer surface does not substantially function for the heating tubes 11, 11,. It was an impediment.

  Then, the main subject of this invention is improving the utilization efficiency of a heating medium, and improving a drying capability.

The present invention according to claim 1 for solving the above-mentioned problem is
A rotating cylinder, a plurality of heating tubes provided in the rotating cylinder, a rotation driving means for rotating the rotating cylinder around its central axis, and a cover provided on one end side and the other end side of the rotating cylinder, respectively. A dry product supply unit and a dry product discharge unit, wherein the dry product is indirectly heated by the heat of the heating medium circulated in the heating tube group in the course of the dry product from the supply unit to the discharge unit in the rotating cylinder. In a dryer configured to be dried,
A condensate chamber formed at an axial end of the rotating cylinder and communicating with an end opening of the heating tube group; and
A plurality of header chambers located radially outward from the condensate chamber and communicating with the condensate chamber, separated in the circumferential direction;
The indirect heating is characterized in that the condensate of the heating medium is guided from the header chamber into the discharge passage by a header pipe connecting the header chamber and the discharge passage provided on the central axis side. It is a rotary dryer with a tube.

In the present invention, the condensate chamber in which the end opening of the heating tube group communicates, and a plurality of headers positioned radially outward from the condensate chamber and communicating with the condensate chamber and separated in the circumferential direction And a condensate of the heating medium is guided from the header chamber into the discharge path by a header pipe.
That is, since the condensate is allowed to flow out from the outermost part in the radial direction, the condensate does not stay in the condensate chamber, or the amount of the condensate is very small. It can be effectively used for heat transfer, the utilization efficiency of the heating medium is improved, and the drying capacity per volume of the dryer can be increased.
Further, letting the condensate flow out from the outermost side in the radial direction means that the condensate is discharged smoothly because the condensate is discharged at a high head energy state. Also from this point of view, the condensate remaining in the header pipe is extremely small in one rotation of the rotary cylinder.

  According to a second aspect of the present invention, when the header tube is viewed from the outer side of the end of the rotating cylinder, the rotation direction of the rotating cylinder is between the distal end side on the header chamber side and the proximal end side on the discharge path side. It is a rotary dryer with an indirect heating pipe | tube of Claim 1 currently curving on the opposite side.

  When the header tube is bent to the opposite side of the rotation direction of the rotation tube as viewed from the outside of the rotation tube end, the condensate can be smoothly guided to the discharge path through the header tube.

  According to a third aspect of the present invention, the header pipe extends in the radial direction of the rotary cylinder by connecting the first portion extending outwardly to the side of the header chamber and the first portion to the discharge path. The rotary dryer with an indirect heating pipe according to claim 1, further comprising:

  If the header pipe is formed with a first portion that extends outward from the side of the header chamber (outward in the direction of the rotating cylinder axis), the transition of the condensate from the header chamber to the header pipe becomes smooth.

  According to a fourth aspect of the present invention, the first portion and the second portion are curved to the opposite side of the rotation direction of the rotary cylinder when viewed from the outside of the end of the rotary cylinder. This is a rotary dryer with an indirect heating tube.

  The configuration according to claim 3, wherein the first portion and the second portion are configured to be curved in a direction opposite to the rotation direction of the rotating cylinder when viewed from the outside of the rotating cylinder end. The liquid can be smoothly guided to the discharge path through the header pipe.

  The invention according to claim 5 is the rotary dryer with an indirect heating pipe according to claim 1, wherein the header chamber is separated by a separation wall, and the leading end of the header pipe communicates in front of the separation wall. It is.

  The condensate in the header chamber can be smoothly transferred into the header pipe.

According to a sixth aspect of the present invention, the header chamber is separated by a separation wall, and the separation wall is positioned such that the dried material supply side in the axial direction of the rotating cylinder is located in front of the rotating cylinder in the rotation direction, and It is inclined so that the material discharge side in the axial direction is located rearward in the rotation direction,
The header tube has a first portion extending outwardly from the header chamber, and the first portion is inclined at substantially the same angle, and the tip of the header tube Is a rotary drier with an indirect heating pipe according to claim 1, which communicates in front of the separation wall.

  The effect of smoothly transferring the condensate in the header chamber into the header pipe is high.

  The invention according to claim 7 is the rotary dryer with an indirect heating pipe according to claim 6, wherein the inclination angle formed with respect to the cross section is 30 to 80 degrees.

  The effect that the condensate in the header chamber can be smoothly transferred into the header pipe becomes apparent when the inclination angle is 30 to 80 degrees.

  The invention which concerns on Claim 8 is the drying method by the rotary dryer with an indirect heating pipe | tube which dries to-be-dried material using the rotary dryer with an indirect heating pipe | tube of any one of Claims 1-7.

  As described above, according to the present invention, the utilization efficiency of the heating medium can be improved and the drying capacity can be increased.

FIG. 1 is a front view of a steam tube dryer according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the end of the rotating cylinder. FIG. 3 is a longitudinal sectional view of the end of the rotating cylinder. It is an AA arrow line view of FIG. It is explanatory drawing of the other example of arrangement | positioning of a heating tube group. It is explanatory drawing of other embodiment. It is a graph of an experimental result. It is outline | summary explanatory drawing of a prior art example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.
1 to 4 show a steam tube dryer 1 to which the present invention is applied. The steam tube dryer 1 includes a horizontally long rotating cylinder 10. Tires 16 are provided on the outer peripheral surface on both sides in the direction of the central axis x of the rotary cylinder 10, and the rotary cylinder 10 can be rotated by a support roller 17 installed on a base 18 via these tires 16. It is supported. The width between the support rollers 17 and the inclination angle in the longitudinal direction (inclination angle of the downward gradient toward the discharge part of the dried product) are selected in accordance with the downward inclination and diameter of the rotating cylinder 10.

  Further, in order to rotate the rotating cylinder 10, a driven gear 19 is provided around the rotating cylinder 10, and a driving gear (not shown) is engaged with the rotating cylinder 10, and the driving gear 21 is rotated by this driving gear. The force is transmitted through the speed reducer 20 so that the rotary cylinder 10 rotates about its axis.

  An object to be dried 12 is connected via a rotary joint 13 to one side of the rotary cylinder 10 in the direction of the central axis x. The supply unit 12 can be configured by various conveyors or chutes that communicate with the rotary cylinder 10. The material to be dried is inserted into the rotary cylinder 10 through the rotary joint 13 from the supply unit 12 fixedly installed.

A large number of heating tubes 11 are arranged in the rotating cylinder 10. The heating tube 11 is arranged in parallel to the direction of the central axis x of the rotary cylinder 10. More specifically, as in the example shown in FIGS. 4 and 5, the heating tube 11 is arranged on the entire wall side (the outer peripheral portion excluding the central portion) in the rotating cylinder 10. The number and arrangement of the heating tubes 11 can be determined as appropriate.
The heating tube 11 is supported by end plates 10 </ b> A on both sides of the rotating cylinder 10. If necessary, in order to support the heating tube 11, a support plate (not shown) can be added at an intermediate position in the longitudinal direction in the rotary cylinder 10. A heating medium S, which will be described later, for example, heating steam, is supplied to the heating tube 11.

  The to-be-dried material charged in the rotating cylinder 10 is successively supplied by being installed with a downward gradient while being repeatedly dropped after being lifted in the circumferential direction by the rotation of the rotating cylinder 10. It is transferred from the section 12 toward the discharge section 14. In this process, the object to be dried is heated by contact with the heating tube 11 and drying proceeds. A dry matter discharge unit 14 is provided at the end of the rotating cylinder 10 opposite to the supply unit 12. The discharge unit 14 can be configured by a chute or the like.

  An exhaust gas outlet 15 for discharging gas such as steam generated by drying is provided on the discharge unit 14 side in the rotary cylinder 10. The exhaust gas from the exhaust gas outlet 15 can be configured to be released to the atmosphere via an exhaust gas treatment facility (not shown) as necessary.

  On the other hand, in the embodiment of the heating medium supply / discharge system, it is provided at the end of the rotating cylinder 10 on the discharge portion 14 side, and a specific structural example is shown in FIGS. That is, a supply unit 82 for the heating medium S is provided at the end of the rotating cylinder 10 on the discharge unit 14 side, and the heating medium S is supplied into each of the heating pipes 11, 11. It is not shown because there are.)

The condensate D of the heating medium S that has passed through the heating tube 11 has the following structure, and is finally discharged out of the dryer via the downflow path 80.
That is, a condensate chamber 30 in which the end openings of the heating tubes 11, 11... Communicate is formed at the end of the rotating cylinder 10. Further, a plurality of (three in the illustrated example) header chambers 31, 31... Are formed that are located radially outward from the condensate chamber 30 and communicate with the condensate chamber 30 and are separated in the circumferential direction. Yes. As shown in FIG. 3, the condensate chamber 30 and the header chamber 31 communicate with each other through a large number of small holes 32 formed in the outer peripheral wall 30 o of the condensate chamber 30. 30i is an inner peripheral wall.

  A discharge path 34 is provided on the center axis x core side of the rotary cylinder 10, the header chamber 31 and the discharge path 34 are connected by a header pipe 33, and the condensate D of the heating medium (steam) S is transferred to the header chamber. It is comprised so that it may guide in the discharge path 34 from 31 through the header pipe | tube 33. FIG.

  As shown in FIG. 2, the header tube 33 is bent in the direction opposite to the rotation direction of the rotary cylinder 10 when viewed from the outside of the end of the rotary cylinder 10 (when viewed from the right side to the left side in FIG. 3). If so, the condensate D can be smoothly guided to the discharge path 34 through the header pipe 33.

  The header pipe 33 is connected to a first portion 33A extending outward from the header chamber 31 and a second portion extending in the radial direction of the rotary cylinder 10 by connecting the first portion 33A and the discharge path 34. It is desirable to have a portion 33B.

  As clearly shown in FIGS. 2 and 3, the header pipe 33 has a first extending outward from the side of the header chamber 31 (outward in the central axis x direction of the rotating cylinder 10: rightward in FIG. 3). When the portion 33A is formed, the transition of the condensate from the header chamber 31 to the header pipe 33 becomes smooth.

  Further, as shown in FIG. 2, the first portion 33A and the second portion 33B are curved to the opposite side of the rotation direction of the rotary cylinder 10 when viewed from the outside of the end of the rotary cylinder 10. The embodiment is suitable, and can be smoothly guided to the discharge path 34 through the header pipe 33.

  As shown in FIG. 2, the header chamber 31 is separated by a plurality of separation walls 31 </ b> A, and a header pipe 33 is connected to each divided header chamber 31. The end of each header pipe 33 can take a form communicating with the vicinity of the separation wall 31 </ b> A located rearward in the rotation direction among the two separation walls 31 </ b> A forming the header chamber 31 to be connected. As shown in FIG. 2, when the rotating cylinder 10 is rotated clockwise, the condensate staying in the header chamber 31 is relatively opposite to the rotating direction of the rotating cylinder 10 (reverse direction). Therefore, the condensate in the header chamber 31 can be smoothly transferred into the header pipe 33 along the inclination of the separation wall 31 </ b> A. In addition, it is preferable to adjust the number of separation walls 31A so that the header chamber can be divided into 3 to 6 chambers.

  As shown in FIG. 2, the first portion 33 </ b> A of the header pipe 33 is preferably connected to the header chamber 31 at an inclination. The inclination angle between the first portion 33A and the header chamber 31 is substantially the same as the inclination angle of the separation wall 31A (inclination angle θ formed between the cross section of the dryer) and the condensate liquid. The flow is smooth.

  The effect of allowing the condensate in the header chamber 31 to be smoothly transferred into the header pipe 33 is manifested when the inclination angle θ is preferably 30 to 80 degrees, particularly preferably 45 to 75 degrees.

  The dryer according to the present invention includes high-density polyethylene, polycarbonate, polyester carbonate, polyphenylene ether, polyvinyl chloride, atomized iron powder, porous alumina, polyacetal, coal, corn germ fiber, iron oxide, calcium carbonate, potassium fluoride, As represented by drying silica gel, gluten feed, beer lees, polyethylene, methylcellulose, dried sludge and the like, it can be applied to a wide range of uses.

  The arrangement of the heating tubes 11 is not only along the radial direction as shown in FIG. 4, but also as shown in FIG. As for the arrangement, it is desirable that the outer heating tube is located at a rear position delayed with respect to the rotation direction of the rotary cylinder 10. In particular, when the rotating cylinder 10 rotates at a high speed, the lifted dry matter can be dropped by its own weight along the arrangement line L without causing stagnation of the dry matter between the heating tube 11 groups in the rotating cylinder 10. It has been found that the frequency of contact with the heating tube 11 can be increased, and the drying efficiency is higher than that in the form of FIG.

While again shown the form shown in FIG. 2, will be described another example by Figure 6, the first, the inclination angle θ of the separation wall 31A, it can be modified as the separation wall 31A _0. Second, the length of the first portion 33A can be a longer first portion 331. Thirdly, the header tube 33 can be a generally curved and curved header tube 332.

(Other)
As mentioned above, although preferred embodiment was described, various deformation | transformation are possible for this invention within the range. For example, although the above example uses steam as the heating medium, other heating media can also be used. It can be applied singly or in combination within the scope of the present invention.

For the dryers having substantially the same size, the peripheral speed V of the rotating cylinder is changed for each of the rotational speeds of the rotating cylinder in the example of the patent document 1 (conventional example) and the example of FIG. The amount of condensate remaining in the condensate chamber and the header chamber was determined by simulation.
The simulation conditions are as follows.
Conventional example (1): peripheral speed V1 = 0.95 m / sec (critical speed ratio α = 21%)
Conventional example (2): peripheral speed V2 = 2.0 m / sec, (critical speed ratio α = 44%)
The present invention: peripheral speed V2 = 2.0 m / sec (critical speed ratio α = 44%)

The results are shown in FIG.
According to the result of FIG. 7, in the conventional example, when the peripheral speed of the rotating cylinder is increased, the amount of condensate and the amount of condensate remaining in the header chamber tends to increase with the increase in the number of rotations. This is because the amount of condensate that can be discharged to the discharge passage per revolution is small compared to the amount of condensate that flows into the condensate chamber per revolution, and the difference remains in the condensate chamber and the header chamber. Show. On the other hand, when the peripheral speed of the rotating cylinder is reduced, an increase in the residual amount of condensate accompanying an increase in the number of rotations can be suppressed, but a certain amount of condensate remains in the condensate chamber and the header chamber. .
On the other hand, according to the header pipe of the present invention, even when the peripheral speed is increased, the remaining amount of the condensate is less in each stage than the conventional example, and the condensate remains due to the increase in the number of rotations. The amount does not change. This means that every time, the entire amount of newly taken-in condensate is discharged to the discharge path.
According to the present invention, even if the peripheral speed of the rotating cylinder is increased, the condensate discharge capacity is less than the amount of condensate flowing in, and thus the dryer can be operated at a higher peripheral speed than before. It is particularly suitable for a dryer that operates at a rotational speed at which the critical speed ratio α determined by the following formulas 1 and 2 is less than 30 to 100%.
Vc = 2.21D ^1/2 ... Formula 1
α = V / Vc · 100 Equation 2
Where Vc is the critical speed (m / s), D is the inner diameter (m) of the rotating cylinder, and α is the critical speed ratio (%).
V is the rotational speed (m / s).
Specifically, a desired critical speed ratio is set, and the number of revolutions of the dryer is determined from Equations 3 and 4.
Nc = 42.2 / D ^1/2 Formula 3
N = V / Vc × Nc Equation 4
N is the rotational speed (rpm), V is the rotational speed (m / s), Vc is the critical speed (m / s), and Nc is the critical rotational speed (rpm). .).

  DESCRIPTION OF SYMBOLS 1 ... Steam tube dryer, 10 ... Rotating cylinder, 11 ... Heating pipe, 12 ... Insertion part, 13 ... Rotary joint, 14 ... Discharge part, 30 ... Condensate chamber, 31 ... Header room, 31A ... Separation wall, 33 ... Header pipe, 33A ... first part, 33B ... second part, 34 ... discharge path.

  The present invention relates to a rotary dryer with an indirect heating tube and a drying method, and in particular, while rotating a rotating cylinder around its central axis, the material to be dried supplied to one end thereof is moved to the other end. With an indirect heating tube that supplies a heating medium to a number of heating tubes arranged in the rotating cylinder, contacts the moving object to be dried with this heating tube, and then discharges it from the other side of the rotating cylinder The present invention relates to a rotary dryer and a drying method.

  A rotary dryer with an indirect heating tube, typically represented by a steam tube dryer, is characterized by a large heating area per volume, and therefore a large drying capacity and a high heat transfer rate.

  Furthermore, since the heating medium and the object to be dried are not in direct contact, the object to be dried is not mixed in the heating medium, no processing equipment for separating the object to be dried in the heating medium is required, and the operation is easy. It is widely used in the chemical industry, food industry, steel industry, etc., and has many achievements for drying terephthalic acid, synthetic resin, soda ash, fertilizer, corn products, coal and the like.

  This dryer usually has a length of 10 to 30 m, and in a rotating cylinder, the wet powder or granular material is brought into contact with a heating tube heated by a circulating heating medium such as steam or heated air, and rotated. As the tube rotates, it is continuously dried while being moved to the discharge port. A heating medium for heating the heating tube is supplied to the heating tube via the rotary joint, and heat is supplied to the wet powder through the heating tube to dry the wet powder. The heating medium itself condenses in the heating tube to become a condensate, flows countercurrently to the heating medium along the gradient of the dryer, and is discharged from one end of the rotating cylinder.

A conventional dryer will be described with reference to FIG. In the conventional dryer, the heating medium S is supplied from the pipe 81 to the inside of the dryer through a rotary joint. The condensate chamber 30 is provided with a pipe 33A that penetrates the inner wall 30i and communicates with the pipe 81, and the heating medium S is supplied to the condensate chamber 30 through the pipe 33A and is supplied into each heating pipe 11. The heating tube 11 is heated. The heating medium S that has heated the inside of the heating tube 11 becomes the condensate D and flows down below the condensate chamber 30. The condensate D that has flowed down passes through the header pipe 33 </ b> B connected to the inner wall 30 i of the condensate liquid chamber 30 and is discharged from the discharge path 34 to the outside through the pipe 80.

  Examples of the condensate discharge mode include Patent Document 1 and Patent Document 2.

Japanese Patent No. 3894499 Japanese Patent Publication No.42-8110

  However, in the conventional rotary dryer with an indirect heating tube, in order to move the dried product toward the dried product discharge portion of the rotary cylinder and discharge it, the rotary cylinder 10 also has a factor of being arranged in a downward slope, 10 is formed at the end in the axial direction, and the condensate tends to stay in the condensate chamber 30 where the end openings of the heating tubes 11, 11... Communicate with each other. Since the heating medium does not circulate for the groups 11, 11,..., The heat transfer surface does not substantially function for the heating tubes 11, 11,. It was an impediment.

  Then, the main subject of this invention is improving the utilization efficiency of a heating medium, and improving a drying capability.

The present invention according to claim 1 for solving the above-mentioned problem is
A rotating cylinder, a plurality of heating tubes provided in the rotating cylinder, a rotation driving means for rotating the rotating cylinder around its central axis, and a cover provided on one end side and the other end side of the rotating cylinder, respectively. A dry product supply unit and a dry product discharge unit, wherein the dry product is indirectly heated by the heat of the heating medium circulated in the heating tube group in the course of the dry product from the supply unit to the discharge unit in the rotating cylinder. In a dryer configured to be dried,
A condensate chamber formed at an axial end of the rotating cylinder and communicating with an end opening of the heating tube group; and
A plurality of header chambers located radially outward from the condensate chamber and communicating with the condensate chamber, separated in the circumferential direction;
The indirect heating is characterized in that the condensate of the heating medium is guided from the header chamber into the discharge passage by a header pipe connecting the header chamber and the discharge passage provided on the central axis side. It is a rotary dryer with a tube.

In the present invention, the condensate chamber in which the end opening of the heating tube group communicates, and a plurality of headers positioned radially outward from the condensate chamber and communicating with the condensate chamber and separated in the circumferential direction And a condensate of the heating medium is guided from the header chamber into the discharge path by a header pipe.
That is, since the condensate is allowed to flow out from the outermost part in the radial direction, the condensate does not stay in the condensate chamber, or the amount of the condensate is very small. It can be effectively used for heat transfer, the utilization efficiency of the heating medium is improved, and the drying capacity per volume of the dryer can be increased.
Further, letting the condensate flow out from the outermost side in the radial direction means that the condensate is discharged smoothly because the condensate is discharged at a high head energy state. Also from this point of view, the condensate remaining in the header pipe is extremely small in one rotation of the rotary cylinder.

  According to a second aspect of the present invention, when the header tube is viewed from the outer side of the end of the rotating cylinder, the rotation direction of the rotating cylinder is between the distal end side on the header chamber side and the proximal end side on the discharge path side. It is a rotary dryer with an indirect heating pipe | tube of Claim 1 currently curving on the opposite side.

  When the header tube is bent to the opposite side of the rotation direction of the rotation tube as viewed from the outside of the rotation tube end, the condensate can be smoothly guided to the discharge path through the header tube.

  According to a third aspect of the present invention, the header pipe extends in the radial direction of the rotary cylinder by connecting the first portion extending outwardly to the side of the header chamber and the first portion to the discharge path. The rotary dryer with an indirect heating pipe according to claim 1, further comprising:

  If the header pipe is formed with a first portion that extends outward from the side of the header chamber (outward in the direction of the rotating cylinder axis), the transition of the condensate from the header chamber to the header pipe becomes smooth.

  According to a fourth aspect of the present invention, the first portion and the second portion are curved to the opposite side of the rotation direction of the rotary cylinder when viewed from the outside of the end of the rotary cylinder. This is a rotary dryer with an indirect heating tube.

  The configuration according to claim 3, wherein the first portion and the second portion are configured to be curved in a direction opposite to the rotation direction of the rotating cylinder when viewed from the outside of the rotating cylinder end. The liquid can be smoothly guided to the discharge path through the header pipe.

  The invention according to claim 5 is the rotary dryer with an indirect heating pipe according to claim 1, wherein the header chamber is separated by a separation wall, and the leading end of the header pipe communicates in front of the separation wall. It is.

  The condensate in the header chamber can be smoothly transferred into the header pipe.

According to a sixth aspect of the present invention, the header chamber is separated by a separation wall, and the separation wall is positioned such that the dried material supply side in the axial direction of the rotating cylinder is located in front of the rotating cylinder in the rotation direction, and It is inclined so that the material discharge side in the axial direction is located rearward in the rotation direction,
The header pipe has a first portion extending outwardly from the header chamber, and the first portion is inclined at an angle substantially the same as the inclination angle of the separation wall, The tip of is a rotary dryer with an indirect heating pipe according to claim 1, which communicates with the front side close to the separation wall.

  The effect of smoothly transferring the condensate in the header chamber into the header pipe is high.

  The invention according to claim 7 is the rotary dryer with an indirect heating pipe according to claim 6, wherein the inclination angle formed with respect to the cross section is 30 to 80 degrees.

  The effect that the condensate in the header chamber can be smoothly transferred into the header pipe becomes apparent when the inclination angle is 30 to 80 degrees.

  The invention which concerns on Claim 8 is the drying method by the rotary dryer with an indirect heating pipe | tube which dries to-be-dried material using the rotary dryer with an indirect heating pipe | tube of any one of Claims 1-7.

  As described above, according to the present invention, the utilization efficiency of the heating medium can be improved and the drying capacity can be increased.

FIG. 1 is a front view of a steam tube dryer according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the end of the rotating cylinder. FIG. 3 is a longitudinal sectional view of the end of the rotating cylinder. It is an AA arrow line view of FIG. It is explanatory drawing of the other example of arrangement | positioning of a heating tube group. It is explanatory drawing of other embodiment. It is a graph of an experimental result. It is outline | summary explanatory drawing of a prior art example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.
1 to 4 show a steam tube dryer 1 to which the present invention is applied. The steam tube dryer 1 includes a horizontally long rotating cylinder 10. Tires 16 are provided on the outer peripheral surface on both sides in the direction of the central axis x of the rotary cylinder 10, and the rotary cylinder 10 can be rotated by a support roller 17 installed on a base 18 via these tires 16. It is supported. The width between the support rollers 17 and the inclination angle in the longitudinal direction (inclination angle of the downward gradient toward the discharge part of the dried product) are selected in accordance with the downward inclination and diameter of the rotating cylinder 10.

  Further, in order to rotate the rotating cylinder 10, a driven gear 19 is provided around the rotating cylinder 10, and a driving gear (not shown) is engaged with the rotating cylinder 10, and the driving gear 21 is rotated by this driving gear. The force is transmitted through the speed reducer 20 so that the rotary cylinder 10 rotates about its axis.

  An object to be dried 12 is connected via a rotary joint 13 to one side of the rotary cylinder 10 in the direction of the central axis x. The supply unit 12 can be configured by various conveyors or chutes that communicate with the rotary cylinder 10. The material to be dried is inserted into the rotary cylinder 10 through the rotary joint 13 from the supply unit 12 fixedly installed.

A large number of heating tubes 11 are arranged in the rotating cylinder 10. The heating tube 11 is arranged in parallel to the direction of the central axis x of the rotary cylinder 10. More specifically, as in the example shown in FIGS. 4 and 5, the heating tube 11 is arranged on the entire wall side (the outer peripheral portion excluding the central portion) in the rotating cylinder 10. The number and arrangement of the heating tubes 11 can be determined as appropriate.
The heating tube 11 is supported by end plates 10 </ b> A on both sides of the rotating cylinder 10. If necessary, in order to support the heating tube 11, a support plate (not shown) can be added at an intermediate position in the longitudinal direction in the rotary cylinder 10. A heating medium S, which will be described later, for example, heating steam, is supplied to the heating tube 11.

  The to-be-dried material charged in the rotating cylinder 10 is successively supplied by being installed with a downward gradient while being repeatedly dropped after being lifted in the circumferential direction by the rotation of the rotating cylinder 10. It is transferred from the section 12 toward the discharge section 14. In this process, the object to be dried is heated by contact with the heating tube 11 and drying proceeds. A dry matter discharge unit 14 is provided at the end of the rotating cylinder 10 opposite to the supply unit 12. The discharge unit 14 can be configured by a chute or the like.

  An exhaust gas outlet 15 for discharging gas such as steam generated by drying is provided on the discharge unit 14 side in the rotary cylinder 10. The exhaust gas from the exhaust gas outlet 15 can be configured to be released to the atmosphere via an exhaust gas treatment facility (not shown) as necessary.

On the other hand, in the embodiment of the heating medium supply / discharge system, it is provided at the end of the rotating cylinder 10 on the discharge portion 14 side, and a specific structural example is shown in FIGS. That is, a supply pipe 81 of the heating medium S is provided at the end of the rotating cylinder 10 on the discharge section 14 side, and the heating medium S is supplied into each of the heating pipes 11, 11,. It is not shown because there are.)

The condensate D of the heating medium S that has passed through the heating tube 11 has the following structure, and is finally discharged out of the dryer via the downflow path 80.
That is, a condensate chamber 30 in which the end openings of the heating tubes 11, 11... Communicate is formed at the end of the rotating cylinder 10. Further, a plurality of (three in the illustrated example) header chambers 31, 31... Are formed that are located radially outward from the condensate chamber 30 and communicate with the condensate chamber 30 and are separated in the circumferential direction. Yes. As shown in FIG. 3, the condensate chamber 30 and the header chamber 31 communicate with each other through a large number of small holes 32 formed in the outer peripheral wall 30 o of the condensate chamber 30. 30i is an inner peripheral wall.

  A discharge path 34 is provided on the center axis x core side of the rotary cylinder 10, the header chamber 31 and the discharge path 34 are connected by a header pipe 33, and the condensate D of the heating medium (steam) S is transferred to the header chamber. It is comprised so that it may guide in the discharge path 34 from 31 through the header pipe | tube 33. FIG.

  As shown in FIG. 2, the header tube 33 is bent in the direction opposite to the rotation direction of the rotary cylinder 10 when viewed from the outside of the end of the rotary cylinder 10 (when viewed from the right side to the left side in FIG. 3). If so, the condensate D can be smoothly guided to the discharge path 34 through the header pipe 33.

  The header pipe 33 is connected to a first portion 33A extending outward from the header chamber 31 and a second portion extending in the radial direction of the rotary cylinder 10 by connecting the first portion 33A and the discharge path 34. It is desirable to have a portion 33B.

  As clearly shown in FIGS. 2 and 3, the header pipe 33 has a first extending outward from the side of the header chamber 31 (outward in the central axis x direction of the rotating cylinder 10: rightward in FIG. 3). When the portion 33A is formed, the transition of the condensate from the header chamber 31 to the header pipe 33 becomes smooth.

  Further, as shown in FIG. 2, the first portion 33A and the second portion 33B are curved to the opposite side of the rotation direction of the rotary cylinder 10 when viewed from the outside of the end of the rotary cylinder 10. The embodiment is suitable, and can be smoothly guided to the discharge path 34 through the header pipe 33.

  As shown in FIG. 2, the header chamber 31 is separated by a plurality of separation walls 31 </ b> A, and a header pipe 33 is connected to each divided header chamber 31. The end of each header pipe 33 can take a form communicating with the vicinity of the separation wall 31 </ b> A located rearward in the rotation direction among the two separation walls 31 </ b> A forming the header chamber 31 to be connected. As shown in FIG. 2, when the rotating cylinder 10 is rotated clockwise, the condensate staying in the header chamber 31 is relatively opposite to the rotating direction of the rotating cylinder 10 (reverse direction). Therefore, the condensate in the header chamber 31 can be smoothly transferred into the header pipe 33 along the inclination of the separation wall 31 </ b> A. In addition, it is preferable to adjust the number of separation walls 31A so that the header chamber can be divided into 3 to 6 chambers.

  As shown in FIG. 2, the first portion 33 </ b> A of the header pipe 33 is preferably connected to the header chamber 31 at an inclination. The inclination angle between the first portion 33A and the header chamber 31 is substantially the same as the inclination angle of the separation wall 31A (inclination angle θ formed between the cross section of the dryer) and the condensate liquid. The flow is smooth.

  The effect of allowing the condensate in the header chamber 31 to be smoothly transferred into the header pipe 33 is manifested when the inclination angle θ is preferably 30 to 80 degrees, particularly preferably 45 to 75 degrees.

  The dryer according to the present invention includes high-density polyethylene, polycarbonate, polyester carbonate, polyphenylene ether, polyvinyl chloride, atomized iron powder, porous alumina, polyacetal, coal, corn germ fiber, iron oxide, calcium carbonate, potassium fluoride, As represented by drying silica gel, gluten feed, beer lees, polyethylene, methylcellulose, dried sludge and the like, it can be applied to a wide range of uses.

  The arrangement of the heating tubes 11 is not only along the radial direction as shown in FIG. 4, but also as shown in FIG. As for the arrangement, it is desirable that the outer heating tube is located at a rear position delayed with respect to the rotation direction of the rotary cylinder 10. In particular, when the rotating cylinder 10 rotates at a high speed, the lifted dry matter can be dropped by its own weight along the arrangement line L without causing stagnation of the dry matter between the heating tube 11 groups in the rotating cylinder 10. It has been found that the frequency of contact with the heating tube 11 can be increased, and the drying efficiency is higher than that in the form of FIG.

While again shown the form shown in FIG. 2, will be described another example by Figure 6, the first, the inclination angle θ of the separation wall 31A, it can be modified as the separation wall 31A _0. Second, the length of the first portion 33A can be a longer first portion 331. Thirdly, the header tube 33 can be a generally curved and curved header tube 332.

(Other)
As mentioned above, although preferred embodiment was described, various deformation | transformation are possible for this invention within the range. For example, although the above example uses steam as the heating medium, other heating media can also be used. It can be applied singly or in combination within the scope of the present invention.

For the dryers having substantially the same size, the peripheral speed V of the rotating cylinder is changed for each of the rotational speeds of the rotating cylinder in the example of the patent document 1 (conventional example) and the example of FIG. The amount of condensate remaining in the condensate chamber and the header chamber was determined by simulation.
The simulation conditions are as follows.
Conventional example (1): peripheral speed V1 = 0.95 m / sec (critical speed ratio α = 21%)
Conventional example (2): peripheral speed V2 = 2.0 m / sec, (critical speed ratio α = 44%)
The present invention: peripheral speed V2 = 2.0 m / sec (critical speed ratio α = 44%)

The results are shown in FIG.
According to the result of FIG. 7, in the conventional example, when the peripheral speed of the rotating cylinder is increased, the amount of condensate and the amount of condensate remaining in the header chamber tends to increase with the increase in the number of rotations. This is because the amount of condensate that can be discharged to the discharge passage per revolution is small compared to the amount of condensate that flows into the condensate chamber per revolution, and the difference remains in the condensate chamber and the header chamber. Show. On the other hand, when the peripheral speed of the rotating cylinder is reduced, an increase in the residual amount of condensate accompanying an increase in the number of rotations can be suppressed, but a certain amount of condensate remains in the condensate chamber and the header chamber. .
On the other hand, according to the header pipe of the present invention, even when the peripheral speed is increased, the remaining amount of the condensate is less in each stage than the conventional example, and the condensate remains due to the increase in the number of rotations. The amount does not change. This means that every time, the entire amount of newly taken-in condensate is discharged to the discharge path.
According to the present invention, even if the peripheral speed of the rotating cylinder is increased, the condensate discharge capacity is less than the amount of condensate flowing in, and thus the dryer can be operated at a higher peripheral speed than before. It is particularly suitable for a dryer that operates at a rotational speed at which the critical speed ratio α determined by the following formulas 1 and 2 is less than 30 to 100%.
Vc = 2.21D ^1/2 ... Formula 1
α = V / Vc · 100 Equation 2
Where Vc is the critical speed (m / s), D is the inner diameter (m) of the rotating cylinder, and α is the critical speed ratio (%).
V is the rotational speed (m / s).
Specifically, a desired critical speed ratio is set, and the number of revolutions of the dryer is determined from Equations 3 and 4.
Nc = 42.2 / D ^1/2 Formula 3
N = V / Vc × Nc Equation 4
N is the rotational speed (rpm), V is the rotational speed (m / s), Vc is the critical speed (m / s), and Nc is the critical rotational speed (rpm). .).

  DESCRIPTION OF SYMBOLS 1 ... Steam tube dryer, 10 ... Rotating cylinder, 11 ... Heating pipe, 12 ... Insertion part, 13 ... Rotary joint, 14 ... Discharge part, 30 ... Condensate chamber, 31 ... Header room, 31A ... Separation wall, 33 ... Header pipe, 33A ... first part, 33B ... second part, 34 ... discharge path.

Claims (8)

A rotating cylinder, a plurality of heating tubes provided in the rotating cylinder, a rotation driving means for rotating the rotating cylinder around its central axis, and a cover provided on one end side and the other end side of the rotating cylinder, respectively. A dry product supply unit and a dry product discharge unit, wherein the dry product is indirectly heated by the heat of the heating medium circulated in the heating tube group in the course of the dry product from the supply unit to the discharge unit in the rotating cylinder. In a dryer configured to be dried,
A condensate chamber formed at an axial end of the rotating cylinder and communicating with an end opening of the heating tube group; and
A plurality of header chambers located radially outward from the condensate chamber and communicating with the condensate chamber, separated in the circumferential direction;
The indirect heating is characterized in that the condensate of the heating medium is guided from the header chamber into the discharge passage by a header pipe connecting the header chamber and the discharge passage provided on the central axis side. Rotary dryer with tube.   The header pipe is curved in the direction opposite to the rotation direction of the rotating cylinder between the distal end side on the header chamber side and the proximal end side on the discharge path side when viewed from the outside of the rotating cylinder end. The rotary dryer with an indirect heating pipe according to claim 1.   The header pipe has a first portion extending outwardly from the header chamber, and a second portion extending in the radial direction of the rotary cylinder connecting the first portion and the discharge path. The rotary dryer with an indirect heating pipe according to claim 1.   The rotary dryer with an indirect heating tube according to claim 3, wherein the first portion and the second portion are curved to the opposite side to the rotation direction of the rotary cylinder when viewed from the outside of the end of the rotary cylinder. .   The rotary dryer with an indirect heating pipe according to claim 1, wherein the header chamber is separated by a separation wall, and a front end of the header pipe is communicated in front of the separation wall. The header chamber is separated by a separating wall, and the separating wall has a dried material supply side in the axial direction of the rotating cylinder positioned forward in the rotating direction of the rotating cylinder, and a dried object discharge side in the axial direction of the rotating cylinder. Inclined to be located at the rear of the rotation direction,
The header tube has a first portion extending outwardly from the header chamber, and the first portion is inclined at substantially the same angle, and the tip of the header tube The rotary dryer with an indirect heating pipe according to claim 1, which communicates with the front in the vicinity of the separation wall.   The rotary dryer with an indirectly heated tube according to claim 6, wherein the inclination angle formed between the cross section and the cross section is 30 to 80 degrees.   The drying method by the rotary dryer with an indirect heating pipe | tube which dries to-be-dried material using the rotary dryer with an indirect heating pipe | tube of any one of Claims 1-7.

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