JP2010197035A - Heat exchanging system for drying and drying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save electric power necessary for an electric heater in a dehumidifying drying device for a synthetic resin pellet and the like, by performing heat exchange while utilizing a heat pump to surely achieve desired temperature fall and to sufficiently achieve necessary temperature rise. <P>SOLUTION: A heat exchanging system includes a dehumidifying unit 11 for dehumidifying the air passing therethrough, and a drying hopper 21 for drying the synthetic resin pellet X by the dehumidified air passing through the dehumidifying unit 11. An outlet of the dehumidifying unit 11 and an inlet of the drying hopper 21 are connected by a dehumidified air supply line 31, and an exhaust port 23 of the drying hopper 21 and an inlet of the dehumidifying unit 11 are connected by a reflux line 32. A heat absorber 42 of the heat pump 41 having the heat absorber 42 and a radiator 43 is incorporated in an intermediate section of the reflux line 32. besides, an upstream part with respect to an electric heater 31a, of the dehumidified air supply line 31 is passed to the radiator 43 of the heat pump. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drying device, and more particularly to a drying device that can save power.

  Drying, particularly dehumidifying drying, is widely used for drying synthetic resin pellets, agricultural and livestock products, marine products, wood, and the like. This is because when drying with dehumidified air of low humidity, the drying can be performed satisfactorily, the drying operation is not difficult, and damage to the material to be dried (for example, thermal decomposition, color change, loss of ingredients and flavors) is reduced. Because there is.

  One of the objects to be dried as in the above example, a dehumidifying and drying apparatus for synthetic resin pellets, is disclosed in Patent Document 1 below.

  As shown in FIG. 5, the dehumidifying and drying apparatus of Patent Document 1 includes a dehumidifying unit 101 that has a cylindrical shape and rotates at a low speed to dehumidify air passing therethrough, and dehumidified air that has been dehumidified through the dehumidifying unit 101. A drying hopper 102 for drying synthetic resin pellets to be dried is provided. Between the dehumidifying unit 101 and the drying hopper 102, dehumidifying air is supplied to the drying hopper 102, and exhaust gas discharged from the drying hopper 102 is returned to the dehumidifying unit 101, and this dehumidifying circulation line 103 has a cooling line 104 that branches before the dehumidifying unit 101 and is connected to the rear stage side of the drying hopper.

  An electric heater 105 for heating the dehumidified air is provided at an inlet portion of the drying hopper 102 in the dehumidifying circulation line 103. Further, a filter 106, an after cooler 107, and a blower 108 are provided in order from the drying hopper 102 side downstream of the drying hopper 102 and upstream of the dehumidifying unit 101 in the dehumidifying circulation line 103. The aftercooler 107 is for reducing the temperature of the hot exhaust gas discharged from the drying hopper 102, and is important. Due to the presence of the aftercooler 107, damage to the blower 108 can be avoided.

  The dehumidifying unit 101 is divided in a circumferential direction into a dehumidifying zone 101a, a cooling zone 101b, and a regeneration zone 101c. The dehumidifying circulation line 103 is communicated with the dehumidifying zone 101a, and the cooling line 104 is communicated with the cooling zone 101b. The

  In addition to these lines 103 and 104, a regeneration line 109 communicating with the regeneration zone 101c of the dehumidifying unit 101 is provided. The regeneration line 109 is a line for regenerating an adsorbent (not shown) of the dehumidifying unit 101 and supplies hot air having a high temperature of about 200 ° C. to the dehumidifying unit 101. For this purpose, an electric heater 110 and a blower 111 for blowing air are provided to generate hot air. In the figure, 112 is a filter.

  According to this dehumidifying and drying apparatus, while supplying the dehumidified air to the drying hopper 102, the dehumidifying unit 101 that generates the dehumidified air is regenerated, so that the generation capability of the dehumidified air is maintained and good dehumidifying drying can be performed.

  However, in the dehumidification circulation line 103, the exhaust air is cooled by the aftercooler 107 to protect the blower 108, and then the dehumidified air is heated by the electric heater 105. In the regeneration line 109, the sucked room temperature air is heated by the electric heater 110. In other words, it was intended to cool and heat air independently on a per-site basis, and energy efficiency was not considered.

  For this reason, the dehumidification drying apparatus as disclosed by the following patent document 2 was proposed. As shown in FIG. 6, the dehumidifying / drying apparatus extends the upstream side of the regeneration line 109 in the dehumidifying / drying apparatus of FIG. 5 to the exhaust port 102a portion of the drying hopper 102 of the dehumidifying circulation line 103, and is appropriately lengthened. Further, the dehumidification circulation line 103 and the regeneration line 109 are provided side by side, and the portions that are aligned with each other serve as a heat exchanger 113.

  The heat exchanger 113 is composed of a double tube comprising an inner tube and an outer tube (not shown), and the inner tube constitutes the regeneration line 109. One end of the inner tube is open to the outside air. Further, the exhaust port 102 a of the drying hopper 102 is connected to the space between the inner tube and the outer tube, and the space between the inner tube and the outer tube constitutes the dehumidification circulation line 103.

  In other words, the high-temperature exhaust discharged from the exhaust port 102a of the drying hopper 102 moves downstream in the space between the inner tube and the outer tube, and at the same time, the normal temperature outside air sucked into the inner tube also flows into the inner tube. Move downstream. During this time, heat exchange is performed, and the temperature of the exhaust gas coming out of the drying hopper 102 is lowered to a temperature at which the blower 108 is not damaged, while the temperature of the outside air sucked into the inner pipe is raised to a temperature at which the blower 111 is not damaged. That is, the heat of the exhaust gas passing through the dehumidification circulation line 103 is used for raising the temperature of the air in the regeneration line 109. Thereby, power saving of the electric heater 110 of the regeneration line 109 can be achieved, and thermal energy can be saved.

  However, the heat utilization by the heat exchanger as in Patent Document 2 is to move the heat on the high temperature side to the low temperature side, and as a result of the heat exchange, both temperatures are directed in the direction of equalization. Specifically, for example, in the dehumidification circulation line 103, assuming that 120 ° C. exhaust is lowered to about 70 ° C. for blower protection, the ambient temperature outside air is raised to nearly 70 ° C. in the regeneration line 109. The

  For this reason, for example, the temperature of the air entering the regeneration line 109 cannot be raised to a temperature close to the exhaust temperature. In other words, even if the heat energy is saved, it is only performed by moving the heat naturally from the higher to the lower one, and there is still room for improvement in terms of power saving of the electric heater. However, in the configuration disclosed in Patent Document 2, the purpose of protecting the two blowers 108 and 111 has to be achieved, so it is necessary to raise the temperature of the air entering the regeneration line 109 to a temperature close to the exhaust temperature. Not at all.

  Further, in the heat exchanger 113 of Patent Document 2, the movement direction of the exhaust gas in the heat exchanger 113 is the same as the movement direction of the sucked outside air, and the heat exchange efficiency is poor as compared with the counterflow type.

  Moreover, in the heat exchanger 113 that naturally moves heat as disclosed in Patent Document 2, the heat exchange efficiency is determined by the temperature of the outside air to be sucked in, the amount of air blown, and the length of the heat exchanger. It is not always easy to ensure the temperature of both the exhaust air from the air and the outside air to be sucked below a predetermined temperature that prevents the blowers 108 and 111 from being damaged, due to the inefficiency as described above.

  Patent Documents 3 and 4 listed below disclose drying of an object to be dried (molding material, garbage) using a heat pump for power saving. That is, the drying is a configuration in which a radiator in the heat pump is disposed in a portion in which an object to be dried is accommodated. For example, Patent Document 3 below discloses a mold temperature control device that uses a heat pump to dry a synthetic resin as a molding material. In this mold temperature control device, a heat exchanger (heat radiator) of the heat pump is molded. Housed in a material dryer, the radiator heats the inside of the molding material dryer to dry the molding material, and the molding material is dried by a heat pump without using an electric heater. It is described that drying can be performed and power consumption can be reduced.

  However, in such a configuration in which the radiator that is a part of the heat pump is incorporated in the drying device, it is difficult to transmit the heat energy, and it is difficult to apply to the existing drying device from the viewpoint of heat transfer design to the gas. That is, it is difficult to increase the efficiency of thermal energy with respect to existing drying apparatuses.

Japanese Patent No. 2920589 Japanese Patent No. 3914566 Japanese Patent Laying-Open No. 2005-7736 (FIG. 3, [0030] to [0036]) Japanese Patent Laid-Open No. 2003-185342

  Thus, the main object of the present invention is to contribute to power saving by effectively using thermal energy.

  For this purpose, a heat pump is provided in the preceding stage of the drying unit for drying the object to be dried, and a heat exchanger for drying is provided in a hot air supply line in which the heat radiator of the heat pump sends hot air toward the drying unit. System. As the low-temperature heat source of the heat pump, a coolant flowing in the factory, exhaust exhausted from the drying unit, or the like can be used.

  In this system, the hot air that goes to the drying section through the hot air supply line receives heat when it passes through the heat absorber of the heat pump, and the temperature rises. A heat pump actively transfers heat with low energy to generate a desired hot air. If the coolant flowing through the factory or the exhaust discharged from the drying unit is used as the low temperature heat source of the heat pump, unnecessary heat is effectively recovered and used for heat transfer by the heat pump.

  As described above, when the coolant flowing through the factory is used as the low-temperature heat source of the heat pump, the coolant is usually used in a stable and large amount as an infrastructure equipment of the factory. There is no temperature change, the heat balance is easy to plan, and it can be used stably. In addition, when exhaust gas discharged from the drying unit is used, heat energy is transferred in a system that is tightly coupled as a process, so that the heat balance related to the heat pump is stable and can be stably utilized.

  The drying may be dehumidification drying. That is, a heat exchange system for drying comprising a dehumidifying unit that dehumidifies air passing therethrough and a drying unit that dries an object to be dried with the dehumidified air that has passed through the dehumidifying unit, the drying unit to the dehumidifying unit A heat exchange system for drying may be provided, in which a heat pump heat sink using the exhaust from the drying section passing through the reflux line as a low-temperature heat source is provided in the reflux line toward the rear.

  In this system, the exhaust discharged from the drying section is deprived of heat when passing through the heat absorber of the heat pump in the middle of moving to the dehumidifying section through the reflux line, and the temperature is lowered. The exhaust gas from which heat has been removed moves to the dehumidifying section.

  On the other hand, the appropriate fluid that passes through the radiator of the heat pump receives heat and rises in temperature.

  The lowering of the exhaust gas and the higher temperature of the fluid passing through the reflux line can obtain a desired state by controlling the operation of the heat pump that actively transfers heat with low energy.

  The radiator provided in the heat pump is provided in an appropriate line. For example, the heat pump is provided in a dehumidified air supply line that sends dehumidified air from the dehumidifying unit toward the drying unit. An electric heater for heating the dehumidified air may be provided on the downstream side.

  As described above, the exhaust gas passing through the reflux line is cooled, while the temperature of the dehumidified air passing through the dehumidified air supply line rises. This temperature increase can be performed as desired within the limits of the heat pump, reducing the burden on the electric heater that heats the dehumidified air.

  Further, when a heat pump radiator is provided in the dehumidified air supply line as described above, a regeneration line for regenerating the dehumidifying part by sending hot air to the dehumidifying part is connected to the dehumidifying part, A downstream portion of the regeneration line from the dehumidifying portion and an upstream portion of the electric heater that heats the gas passing through the regeneration line may be connected by a heat exchanger.

  The heat in the downstream portion of the regeneration line through which the hot air that has passed through the dehumidifying section and finished the regeneration action passes is moved to the upstream portion of the regeneration line by the heat exchanger, and the temperature of the gas passing through that portion rises. For this reason, the burden of the electric heater for generating hot air in the regeneration line is reduced. In addition, since the electric heater of the regeneration line may generally be an electric heater having a smaller capacity than the electric heater of the dehumidified air supply line, a sufficient temperature rise of the gas can be achieved even with a general heat exchanger. A heat pump is connected to a dehumidified air supply line that requires air at a temperature lower than that of the regeneration line and suitable for heating by the heat pump, and a heat exchanger is used for the regeneration line. Effective use can contribute to power saving.

  Regardless of the presence or absence of the heat exchanger as described above, the radiator provided in the heat pump can also be provided in the regeneration line. That is, a regeneration line for sending hot air to the dehumidifying part to regenerate the dehumidifying part is connected to the dehumidifying part, and the regeneration line is provided with an electric heater for heating gas passing through the regeneration line, and The radiator provided in the heat pump is a heat exchange system for drying provided in an upstream portion of the regeneration line with respect to the electric heater.

  As described above, the exhaust discharged from the drying section is deprived of heat in the heat pump while moving to the dehumidifying section through the reflux line, and is lowered in temperature. Then, the exhaust gas whose temperature has been lowered moves to the dehumidifying section.

  On the other hand, the gas in the regeneration line passing through the heat radiator of the heat pump receives heat in the heat pump and rises in temperature. Further, the gas is heated to a predetermined temperature by an electric heater and used for the regeneration process. Since the gas passing through the regeneration line rises in temperature with a heat pump, it is possible to save power in an electric heater that generates hot air for regeneration.

  Another means is provided with a heat pump using a coolant flowing in the factory as a low-temperature heat source in a stage preceding a drying unit for drying an object to be dried, and a radiator of the heat pump sends hot air toward the drying unit. It is the drying apparatus provided in the hot air supply line.

  Similar to the description of the system described above, the heat pump raises the temperature of the hot air supplied to the drying section.

  When the drying is dehumidification drying, a drying apparatus including a dehumidifying unit that dehumidifies the air passing therethrough, and a drying unit that dries the object to be dried with the dehumidified air that has passed through the dehumidifying unit, from the drying unit It is good that it is a drying apparatus provided with a heat pump heat sink using the exhaust from the drying section passing through the reflux line as a low-temperature heat source in the reflux line toward the dehumidifying section.

  Similar to the description of the system described above, the heat pump lowers the temperature of the exhaust gas exhausted from the drying unit and increases the temperature on the radiator side of the heat pump.

  As described above, according to the present invention, the heat pump actively moves heat with low energy and raises the temperature of the air passing through the supply line. Therefore, the heat energy can be effectively used to realize power saving. .

The whole flow chart of a dehumidification drying system. The flowchart of the whole dehumidification drying system which concerns on another example. The flowchart of the drying system which concerns on another example. The flowchart of the whole dehumidification drying system which concerns on another example. The whole flow figure in the dehumidification drying apparatus of a prior art example. The whole flowchart in the dehumidification drying apparatus of another prior art example.

An embodiment for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is an overall flow diagram showing a heat exchange system for dehumidification drying. In this example, a granular material as an example of an object to be dried, particularly synthetic resin pellets, is dried using the system. A dehumidifying and drying apparatus for synthetic resin pellets will be described.

  This dehumidifying and drying apparatus is for drying resin pellets X with dehumidified air. The dehumidifying unit 11 dehumidifies the passing air, and a drying unit that introduces dehumidified air that has passed through the dehumidifying unit 11 and performs drying. A drying hopper 21 is provided.

  The dehumidifying unit 11 is formed by arranging an adsorbent such as zeolite in a honeycomb shape, and is divided into a dehumidifying zone 12, a cooling zone 13, and a regeneration zone 14 in the circumferential direction. Moreover, it is controlled to rotate at a low speed.

  The drying hopper 21 has a cylindrical shape capable of accommodating the synthetic resin pellet X therein, and is incorporated in one dehumidifying / drying device together with the dehumidifying unit 11.

  The dehumidifying unit 11 and the drying hopper 21 are connected by the following four lines in order to send the dehumidified air exiting the dehumidifying unit 11 to the drying hopper 21 and to regenerate the dehumidifying unit 11.

  The first is the dehumidified air supply line 31. The dehumidified air supply line 31 is a line that supplies dehumidified air that has exited from the outlet side of the dehumidifying unit 11 to the drying hopper 21, and has a starting end that is in communication with the dehumidifying zone 12 of the dehumidifying unit 11 and a terminal that is connected to the supply pipe of the drying hopper 21. 22 is communicated. An electric heater 31a for heating the dehumidified air to a predetermined temperature is provided on the terminal side of the dehumidified air supply line 31. In the case of the resin pellet X, the heating is performed, for example, at about 100 ° C. to 150 ° C., depending on the type of resin.

  Second, the reflux line 32. The reflux line 32 is a line for transferring the exhausted heat discharged from the drying hopper 21 to the dehumidifying unit 11, and has a start end communicating with the exhaust port 23 of the drying hopper 21 and a terminal end on the inlet side of the dehumidifying unit 11. It communicates with the dehumidifying zone 12.

  In the reflux line 32, a cooling line 33 is branched as a third line before the dehumidifying unit 11. The cooling line 33 communicates with the cooling zone 13 on the inlet side of the dehumidifying unit 11, and the tip from the outlet side of the cooling zone 13 is connected to the reflux line 32. The cooling line 33 cools the adsorbent of the dehumidifying unit 11. This is because the adsorbent can be expected to improve the dehumidifying ability at a low temperature.

  Fourth, the reproduction line 34. The regeneration line 34 is a line for supplying high-temperature hot air to the dehumidifying zone 14 of the dehumidifying unit 11 and communicates with the dehumidifying zone 14 of the dehumidifying unit 11. The communication is performed so as to be opposite to the flow direction of the reflux line 32 and the cooling line 33.

  Of these four lines 31, 32, 33, 34, the reflux line 32 and the dehumidified air supply line 31 are connected by a heat pump 41.

  The heat pump 41 includes a heat absorber 42, a radiator 43, a compressor 44, and an expander 45 as is well known. The heat pump 41 uses the exhaust gas transferred through the reflux line 32 as a low-temperature side heat source to lower the temperature of the exhaust gas, while heating the dehumidified air passing through the dehumidified air supply line 31.

  Specifically, the heat absorber 42 of the heat pump 41 is incorporated downstream of the connection portion with the cooling line 33 in the reflux line 32, and the radiator 43 of the heat pump 41 is incorporated in the middle portion of the dehumidified air supply line 31. . A filter 32a is provided upstream of the heat pump 41 in the reflux line 32, and a blower 32b is provided downstream.

  A temperature sensor (not shown) is provided at a position downstream of the electric heater 31 a of the dehumidified air supply line 31, an inlet / outlet to the heat pump 41 in the reflux line 32, and an inlet / outlet to the heat pump 41 in the dehumidified air supply line 31. A thermostat (not shown) or the like is provided as appropriate, and these are appropriately connected to the electric heater 31a, the compressor 44 of the heat pump 41, a temperature controller (not shown), a power controller (not shown), etc., and the drying hopper 21 The temperature of the dehumidified air supplied to is controlled so as to become a preset temperature.

  In the drying of the synthetic resin pellet X, the temperature of the dehumidified air supplied to the drying hopper 21 needs to be about 100 ° C. to 150 ° C., for example. Further, since the blower 32b is provided on the downstream side of the heat pump 41 in the reflux line 32, it is necessary to lower the temperature of the exhaust gas to be transferred to a temperature at which the blower 32b is not damaged, for example, about 70 ° C.

  The regeneration line 34 is independent of the dehumidified air supply line 31, the reflux line 32, and the cooling line 33, and a portion downstream of the dehumidifying unit 11 and a portion upstream of the dehumidifying unit 11 of the regeneration line 34 are dehumidified. It arrange | positions so that a flow direction may oppose in the downstream part rather than the unit 11. FIG. And this opposing part is connected via the heat exchanger 34a.

  In addition, a blower 34b and a filter 34c are arranged on the upstream side of the heat exchanger 34a on the upstream side in order from the upstream side. On the other hand, on the downstream side of the heat exchanger 34a and on the upstream side of the dehumidifying unit 11, an electric heater 34d for heating the outside air sent by the blower 34b to a predetermined temperature necessary for the regeneration of the dehumidifying unit 11 is provided. Is provided.

  In the dehumidifying and drying apparatus configured as described above, the dehumidifying and drying process is performed as follows. First, the dehumidified air that has been dehumidified after passing through the dehumidifying unit 11 through the radiator 43 of the heat pump 41 by the dehumidified air supply line 31 is increased through the refrigerant of the heat pump 41 and increased to a predetermined temperature. Is further heated to a predetermined temperature by the electric heater 31a and supplied to the drying hopper 21 to dry the synthetic resin pellet X in the drying hopper 21.

  The hot exhaust gas supplied to the drying hopper 21 and containing moisture is exhausted from the drying hopper 21 through the reflux line 32. After the foreign matter is removed through the filter 32a, the exhaust gas passes through the heat absorber 42 of the heat pump 41, is deprived of heat through the refrigerant of the heat pump 41, and the temperature is lowered to a predetermined temperature that does not damage the blower 32b. The exhaust gas whose temperature has dropped is sent to the dehumidifying unit 11 by the blower 32b, dehumidified in the dehumidifying zone 12, and circulated through the dehumidified air supply line 31 again.

  On the other hand, the outside air that has been sucked into the blower 34b and entered the regeneration line 34 passes through the filter 34c, removes foreign matter, receives heat from the heat exchanger 34a, rises in temperature, and is further heated by the electric heater 34d. . It is heated to raise the temperature to a predetermined temperature. Then, it is supplied to the dehumidifying unit 11 to regenerate the dehumidifying unit 11.

  The hot air that has been regenerated and has exited from the dehumidifying unit 11 is deprived of heat by the heat exchanger 34a, raises the temperature of the outside air entering the regeneration line 34, and is discharged at a reduced temperature.

  Note that the heating temperature of the outside air by the heat pump 41 is generally affected by the temperature of the exhaust, but in the case of a dehumidifying and drying apparatus, the temperature of the dehumidified air supplied to the drying hopper 21 is controlled to be constant, and Since there is little change in the atmosphere in the factory, the dehumidifying and drying apparatus is not particularly affected by them. For this reason, the heated outside air at a stable temperature can be obtained without particularly complicated control.

  As described above, the heat pump 41 using the exhaust as a low-temperature side heat source lowers the temperature of the exhaust to a predetermined temperature, while giving as much heat energy as possible to the air of the dehumidified air supply line 31 that requires the temperature. Can do. Specifically, about 120 ° C. is possible. For this reason, the raising allowance which must raise temperature with the electric heater 31a in the dehumidification air supply line 31 can be made small, and the electric power consumption of the electric heater 31a can be suppressed.

  Further, since the high-temperature dehumidified air supplied to the drying hopper 21 is raised to a predetermined temperature by the heat pump 41 and then raised in temperature by the electric heater 31a, the main effect of raising the predetermined temperature to the electric heater 31a is borne. Can do. For this reason, strict temperature control can be performed relatively easily, and decomposition and deterioration due to overheating exceeding the limit temperature of the synthetic resin pellet X can be prevented.

  Furthermore, since the heat energy is effectively used by the heat exchanger 34a in the regeneration line 34 as well, power saving can be achieved as a whole.

  FIG. 2 is an overall flow diagram illustrating a heat exchange system for dehumidification drying according to another example. In this example, among the four lines 31, 32, 33, and 34, the reflux line 32 and The regeneration line 34 is connected by a heat pump 41, and the exhaust gas transferred through the reflux line 32 is used as a low-temperature heat source to lower the temperature of the exhaust gas while heating the air entering the regeneration line 34. .

  The configuration will be described below, but the same or equivalent parts as those of the system configuration shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

  A heat absorber 42 of the heat pump 41 is incorporated between the filter 32a and the blower 32b of the reflux line 32, and a radiator 43 of the heat pump 41 is incorporated between the filter 34c and the electric heater 34d of the regeneration line 34.

  Then, a position downstream of the electric heater 31a in the dehumidified air supply line 31, a position downstream of the electric heater 34d in the regeneration line 34, an inlet / outlet to the heat pump 41 in the reflux line 32, and an inlet / outlet to the heat pump 41 in the regeneration line 34. Are provided with a temperature sensor (not shown), a thermostat (not shown), etc. as appropriate, which include the electric heaters 31a and 34d, the compressor 44 of the heat pump 41, a temperature controller (not shown), a power controller. The temperature of the dehumidified air supplied to the drying hopper 21 and the air for regeneration supplied to the dehumidifying unit 11 is controlled so as to be a preset temperature.

  In the drying of the synthetic resin pellet X, the temperature of the dehumidified air supplied to the drying hopper 21 needs to be, for example, about 100 ° C. to 150 ° C., and the temperature of the hot air supplied to the dehumidifying unit 11 is, for example, About 200 ° C is necessary. Further, since the blower 32b is provided on the downstream side of the heat pump 41 in the reflux line 32, it is necessary to lower the temperature of the exhaust gas to be transferred to a temperature at which the blower 32b is not damaged, for example, about 70 ° C. On the other hand, the outside air sent to the regeneration line 34 is desirably raised to a temperature closer to the 200 ° C., but under the above conditions, it can be sufficiently raised to, for example, about 120 ° C.

  In the dehumidifying and drying apparatus configured as described above, the dehumidifying and drying process is performed as follows. First, the dehumidified air passing through the dehumidifying unit 11 is heated to a predetermined temperature by the electric heater 31a by the dehumidified air supply line 31 and supplied to the drying hopper 21, and the synthetic resin pellet X in the drying hopper 21 is dried. To do. The high temperature exhaust gas supplied to the drying hopper 21 and containing moisture is exhausted from the drying hopper 21 through the reflux line 32. After the foreign matter is removed through the filter 32a, the exhaust gas passes through the heat absorber 42 of the heat pump 41, is deprived of heat through the refrigerant of the heat pump 41, and the temperature is lowered to a predetermined temperature that does not damage the blower 32b. The exhaust gas whose temperature has dropped is sent to the dehumidifying unit 11 by the blower 32b, dehumidified in the dehumidifying zone 12, and circulated through the dehumidified air supply line 31 again.

  On the other hand, on the radiator 43 side of the heat pump 41, the outside air sucked into the blower 34b and entered the regeneration line 34 is removed of foreign substances through the filter 34c, receives heat through the refrigerant in the radiator 43, and has a predetermined temperature. Until the temperature is raised. The heated outside air emitted from the heat pump 41 is further heated to a predetermined temperature by the electric heater 34d and then supplied to the dehumidifying unit 11 to regenerate the dehumidifying unit 11.

  Note that the heating temperature of the outside air by the heat pump 41 is generally affected by the temperature of the exhaust and the outside air. However, in the case of a dehumidifying and drying device, the temperature of the dehumidified air supplied to the drying hopper 21 is controlled to be constant. In addition, since there is little change in the atmosphere in the factory, the dehumidifying and drying apparatus is not particularly affected by them. For this reason, the heated outside air at a stable temperature can be obtained without particularly complicated control.

  As described above, even with the configuration as shown in FIG. 2, as in the case of the system shown in FIG. 1, as a whole, it is possible to effectively use thermal energy to save power.

  FIG. 3 is a flow diagram showing a heat exchange system for drying according to another example. In this example, drying is performed by drying synthetic resin pellets X as an example of an object to be dried by hot air instead of dehumidified air. The apparatus will be described.

  The configuration will be described below, but the same or equivalent parts as those in the system configuration shown in FIG. 1 or 2 are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

  The drying apparatus has a drying hopper 21, and a hot air supply line 35 is connected to the drying hopper 21. A blower 35a is provided on the start end side of the hot air supply line 35, and an electric heater 35b is provided on the end side in order to heat the air sucked by the blower 35a to a predetermined temperature. And the radiator 43 of the heat pump 41 is provided in the upstream of this electric heater 35b.

  As a low temperature side heat source of the heat pump 41, a gas such as exhaust from the drying hopper 21 shown in the above example can be used. Moreover, the cooling fluid which flows through the inside of a factory, for example, the cooling liquid used for a cooling tower, an aftercooler, a chiller, other factory equipment, and the apparatus in a factory, can also be used.

  In the drying apparatus configured as described above, the air sucked from the blower 35a receives heat from the radiator 43 of the heat pump 41 and is heated to a predetermined temperature, and then further heated to the predetermined temperature by the electric heater 35b. To the drying hopper 21 to dry the synthetic resin pellet X.

  Thus, the heat pump 41 can give as much heat energy as possible to the air sucked into the hot air supply line 35 that requires temperature. Specifically, about 120 ° C. is possible. For this reason, it is possible to reduce the cost for raising the temperature by the electric heater 35b in the hot air supply line 35, and to suppress the power consumption of the electric heater 35b. As a result, power saving can be achieved.

  Moreover, since the high temperature hot air supplied to the drying hopper 21 is raised to a predetermined temperature by the heat pump 41 and then heated by the electric heater 35b, the main effect of raising the temperature to the predetermined temperature can be borne by the electric heater 35b. it can. For this reason, strict temperature control can be performed relatively easily, and decomposition and deterioration due to overheating exceeding the limit temperature of the synthetic resin pellet X can be prevented. Depending on the capability of the heat pump 41, the electric heater 35a can be omitted.

  Further, the heat pump 41 using a coolant as the low temperature side heat source (water heat source type) has advantages such as higher efficiency and a compact configuration than the air heat source type heat pump. In addition, the coolant is indispensable for the factory and is easy to use. Since the radiator 43 of the heat pump 41 is provided in the hot air supply line 35, it can be applied to an existing drying apparatus, so that a wide range of flexible applications are possible. It is possible to contribute to power saving.

  In addition, as a to-be-dried object, the dehumidification unit 11 as shown in FIG. 1, FIG. 2 may be sufficient.

  FIG. 4 is a flowchart showing the entire heat exchange system for dehumidifying and drying according to another example. In this example, the same dehumidifying and drying apparatus for synthetic resin pellets X as shown in FIGS. 1 and 2 is used. Will be described. The difference from the dehumidifying and drying apparatus shown in FIGS. 1 and 2 is that the dehumidified air supply line 31 and the regeneration line 34 are each provided with a heat pump 41, and the cooler of the aftercooler is used as the low temperature side heat source of the heat pump 41. It is a point using.

  The configuration will be described below, but the same or equivalent parts as those in the system configuration shown in FIG. 1 or 2 are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

  The dehumidifying / drying apparatus includes a dehumidifying unit 11 and a drying hopper 21, which send dehumidified air that has exited the dehumidifying unit 11 to the drying hopper 21 and regenerate the dehumidifying unit 11, as in the above example. Two lines (dehumidified air supply line 31, reflux line 32, cooling line 33, regeneration line 34) are connected.

  As described above, the heat pump 41 is provided in the dehumidified air supply line 31 and the regeneration line 34 to heat the gas passing through the lines 31 and 34. Specifically, the heat radiator 43 of each heat pump 41 is incorporated in each line 31, 34. In addition, two low temperature side heat source supply lines 36 and 37 are provided in order to supply a low temperature side heat source to these heat pumps 41.

  These low-temperature side heat source supply lines 36 and 37 extend from the outlet of the aftercooler 51 provided in the reflux line 32 to the heat absorbers 42 of the heat pumps 41. The aftercooler 51 takes heat from the exhaust in the process of transferring the exhaust with heat discharged from the drying hopper 21 to the dehumidifying unit 11. It is arranged in front of the blower 32b and has the purpose of preventing damage to the blower 32b.

  In addition to this, the hot exhaust gas from the drying hopper 21 is cooled via the aftercooler 51 to prevent damage to the blower 32b, and the low temperature side heat source of the heat pump 41 is generated and used for the operation of the heat pump 41. The exhaust from the drying hopper 21 is indirectly used as a low-temperature heat source for the heat pump 41.

  As described above, the heat pump 41 using the coolant from the aftercooler 51 as a low-temperature heat source gives as much heat energy as possible to the air of the dehumidified air supply line 31 and the air of the regeneration line 34 that require temperature. be able to. In addition, since the cooling liquid coming out of the aftercooler 51 is a stable thermal energy source installed in the infrastructure of the factory, even if the heat balance changes due to the convenience of each function constituting the drying apparatus, it suddenly changes. Temperature does not change and can be used stably. For this reason, it is possible to reduce the heating allowance for increasing the temperature by the electric heaters 31a and 34d in the dehumidified air supply line 31 and the regeneration line 34, and to suppress the power consumption of the electric heaters 31a and 34d.

  In addition, since the air flowing through the dehumidified air supply line 31 and the regeneration line 34 is raised to a predetermined temperature by the heat pump 41 and then heated by the electric heaters 31a and 34d, the main effect of raising the temperature to the predetermined temperature is the electric heater 31a, 34d can be borne. For this reason, strict temperature control can be performed comparatively easily, and decomposition and deterioration due to the adsorbent of the synthetic resin pellet X and the dehumidifying unit 11 exceeding the limit temperature can be prevented.

  Further, since the aftercooler 51 lowers the temperature of the exhaust gas, the blower 32b can be reliably prevented from being damaged.

  Thus, while preventing damage to the blower 32b, the heat of the exhaust can be indirectly used to save power as a whole.

  Furthermore, since the coolant is used as the low-temperature heat source of the heat pump 41, there are advantages such as higher efficiency and a more compact configuration compared to the air heat source type heat pump.

  For the low temperature side heat source of the heat pump 41, it is also possible to use a coolant that circulates in the factory as a coolant for a press machine or an electric discharge machine other than the aftercooler 51, for example.

In the correspondence between the configuration of the present invention and the configuration of the above-described embodiment,
The hot air supply line of the present invention corresponds to the dehumidified air supply line 31 of FIGS. 1 and 4, the regeneration line 34 of FIG. 2 and FIG. 4, and the hot air supply line 35.
Similarly,
The dehumidifying unit corresponds to the dehumidifying unit 11,
The material to be dried corresponds to the synthetic resin pellet X, the dehumidifying unit 11 in FIG.
The drying unit corresponds to the drying hopper 21,
The present invention is not limited to the above-described configuration, and other forms can be adopted.

  For example, the material to be dried may be a granular material other than synthetic resin pellets or various materials, and the drying may be performed by low-temperature dehumidified air.

  Furthermore, the heat exchange system for dehumidifying and drying of the present invention can be used in the case of connecting existing devices in addition to one device such as the aforementioned dehumidifying and drying device.

DESCRIPTION OF SYMBOLS 11 ... Dehumidification unit 21 ... Drying hopper 23 ... Exhaust port 31 ... Dehumidification air supply line 31a ... Electric heater 32 ... Reflux line 34 ... Regeneration line 34a ... Heat exchanger 34d ... Electric heater 35 ... Hot air supply line 41 ... Heat pump 42 ... Endothermic 43 ... Radiator X ... Synthetic resin pellet

Claims (8)

A heat pump is provided in front of the drying section for drying the object to be dried,
A heat exchange system for drying provided in a hot air supply line in which a heat radiator of the heat pump sends hot air toward the drying unit. The heat exchange system for drying according to claim 1, wherein the low-temperature heat source of the heat pump is a coolant flowing in a factory. A heat exchange system for drying comprising a dehumidifying unit for dehumidifying passing air and a drying unit for drying an object to be dried with dehumidified air that has passed through the dehumidifying unit,
A heat exchange system for drying, in which a heat pump heat sink having a low-temperature side heat source is provided in a reflux line from the drying unit to the dehumidifying unit. A radiator provided in the heat pump is provided in a dehumidified air supply line that sends dehumidified air from the dehumidifying unit toward the drying unit,
The heat exchange system for drying according to claim 3, further comprising an electric heater for heating the dehumidified air downstream of the heat pump of the dehumidified air supply line. A regeneration line for sending hot air to the dehumidifying part to regenerate the dehumidifying part is connected to the dehumidifying part,
The heat for drying according to claim 3 or 4, wherein a portion downstream of the dehumidifying portion of the regeneration line and a portion upstream of the electric heater that heats the gas passing through the regeneration line are connected by a heat exchanger. Exchange system. A regeneration line for sending hot air to the dehumidifying part to regenerate the dehumidifying part is connected to the dehumidifying part,
The regeneration line is equipped with an electric heater for heating the gas passing through the regeneration line,
The heat exchange system for drying according to claim 3, wherein a radiator provided in the heat pump is provided in a portion upstream of the electric heater in the regeneration line. A heat pump having a coolant flowing in the factory as a low-temperature side heat source is provided in the front stage of the drying section for drying the object to be dried,
The drying apparatus provided in the hot air supply line which the heat radiator of this heat pump sends a hot air toward the said drying part. A drying apparatus comprising a dehumidifying unit that dehumidifies air passing therethrough, and a drying unit that dries an object to be dried with dehumidified air that has passed through the dehumidifying unit,
The drying apparatus provided with the heat sink of the heat pump which uses the exhaust_gas | exhaustion from the drying part which passes along this reflux line as the low temperature side heat source in the reflux line which goes to the said dehumidification part from the said drying part.

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