JPH043879A - Drying device - Google Patents

Abstract

PURPOSE:To realize a practical drying device by a method wherein materials to be dried are heated and dried by heat generated from a heating means and an adsorbing unit while circulating air through an internal circulating route while adsorbing agent is regenerated by the heating means of the adsorbing agent while supplying air into an external air supplying route. CONSTITUTION:Upon drying, a valve 18 is opened, valves 16, 17 are closed, a fan 8 is operated and another fan 13 is stopped. When a heater 12 is excited under this condition, hot air hits materials 1 to be dried and the drying of the same is started. The temperature of the hot air is regulated so as to be a temperature less than 200 deg.C whereat organic material is not decomposed. Further, humid air is circulated through an adsorbing unit 6. Adsorbing agent 5, being dried previously, adsorbs moisture and generates adsorbing heat. Accordingly, dried and heated air is supplied into a receiving chamber 2 again and, therefore, the drying of the materials 1 to be dried is quickened further and much more moisture is evaporated. In the drying stage for the regeneration of the adsorbing agent 5, external air is taken by the fan 13 and is changed to high-temperature dried air by a heater 14 and is discharged out of the valve 17 through the adsorbing unit 6.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a simple drying device for flammable materials such as kitchen waste, used paper, drafts, and foods. It is difficult to dry food products, etc. using mechanical separation means, and heating drying is often used (for heating drying). (Typical heat transfer methods include convection heat use such as hot air and radiant heat use such as infrared rays.)

Conventional drying equipment uses these heat transfer means to vaporize the water content of the material to be treated and release water vapor.9 Of these, infrared rays are used to treat flat objects such as paint films and open fish. Suitable force (drying three-dimensional objects tends to cause uneven drying and scorching of the surface, making it unsuitable for flammable objects) Also, when vacuum drying under reduced pressure, radiant heat is used as a heat source. If you try to dry quickly, uneven drying tends to occur between areas that are exposed to radiation and areas that are not exposed to radiation. When using such radiant heat, it is necessary to pre-process the material to be treated by crushing, cutting, compressing, etc., so the equipment tends to be large (t) Drying equipment that uses hot air as a heat source does not produce uneven drying as much as drying equipment that uses radiation, so it is possible to dry in the same shape, making it a simple device.Problem that the invention aims to solveAs described above, hot air drying is relatively uniform. If the temperature is too high and the material is dried quickly, the flammable material will ignite or burn. Therefore, the force must be applied to dry the material at a temperature below the decomposition temperature of organic matter (if the temperature is too low, The problem is that it takes too long to dry.

Therefore, methods are taken to dry the object using a large volume of hot air at an appropriate temperature lower than the temperature at which organic matter decomposes. Conventionally, the method of accelerating drying by lowering the humidity of the atmosphere of the processed material is more common.A In such a method, a heat exchanger is installed between the heat of the exhaust air after drying and the air before drying, and the heat is recovered by heat recovery. Although efforts have been made to reduce operating costs, the efficiency of heat recovery from low-temperature, large-volume air is poor.
This requires a large heat exchanger.

When drying by combustion, a large amount of heat can be easily obtained and the fuel cost is relatively low, so this disadvantage may not be a major disadvantage. Therefore, it is difficult to realize a practical drying device.Means for solving the problems Technical means used in the present invention to solve the above conventional problems A storage section for an object to be dried, an adsorption section having a nonflammable adsorbent that adsorbs vaporized moisture of the object to be dried, and means for heating the adsorption material, and a suction section provided between the storage section, the adsorption section, and a blower. an internal circulation path and an external air supply path that circulates external air in the adsorption section, and during drying, air is circulated through the internal circulation path and the material to be dried is connected to the heating means for the material to be dried and the adsorption device. When drying and regenerating the adsorbent, the adsorbent is regenerated by the heating means for the adsorbent while supplying air to the external air supply path. The flow direction is reversed when drying the material to be dried and when drying the adsorbent material to shorten the drying and regeneration time of the adsorbent material.
A hot air temperature detection unit is installed upstream of the flow of the material to be dried.The hot air circulation volume is controlled to keep the temperature constant and the drying time is accelerated. The system is equipped with a function that determines the generation of adsorption heat based on the power consumption of the heater for heating the dried material, and determines the end of drying when the influence of the adsorption heat on the temperature detection section has disappeared. A function is added to determine the end of drying and regeneration of the adsorbent when the temperature of the adsorption part temperature detection part becomes approximately equal to the temperature of the hot air for drying and regeneration. A catalyst is provided at the end of the external air supply path, and a heat exchange section between the external air upstream of the external air supply path and the exhaust gas downstream of the external air supply path is installed to prevent odor and improve heat utilization efficiency. In the present invention, the latent heat of the discharged water vapor is recovered by the adsorbent, and the heat can be used effectively.
Drying can be done in a short period of time without scorching the dried material using low-temperature, large-volume circulating dry air. Therefore, it is possible to realize a small, simple and practical drying device.

EXAMPLES Hereinafter, examples of the present invention will be described based on the accompanying drawings. In FIG. 1, l denotes items to be dried, such as kitchen waste and foodstuffs. The items to be dried 1 are placed onto a grid plate 4 through a door 3 of a storage section 2. A non-flammable adsorbent 5 such as zeolite is used as an adsorption part 6.
It is placed on the grid plate 7 of. The amount of adsorbent 5 contained is greater than the amount that adsorbs all the moisture in the material 1 to be dried. The upstream side (hereinafter simply referred to as upstream and downstream) of the circulation blower 8 in the flow direction is connected to the adsorption section 6, the downstream side is connected to the storage section 2 and the internal circulation path 9, and the downstream side of the storage section 2 is connected to the upstream side of the adsorption section 6. They are connected via an internal circulation path 11.

A drying heater 12 that generates heat when energized is provided in the internal circulation path IO. Air is circulating in the direction of arrow A.

A blower 13 for regeneration and a heater 1 for regeneration are installed above the suction part 6.
4 are provided. The flow direction is arrow B. Also
An exhaust pipe 15 is provided at the bottom of the adsorption section 6. valve 16
, 17 and 18 are provided for switching the flow paths. Furthermore, the device is covered with a heat insulating material 19.

Further, the storage section 2 is provided with a temperature detection section 20, and the suction section is provided with a temperature detection section 21. Further, a catalyst 22 for purifying exhaust gas is provided near the valve 17.

Next, the operation will be explained in detail. Valve 18 is blocked during drying.
With valves 16 and 17 attached, blower 8 is operated and blower 13 is installed.
has stopped. When the heater 12 is energized in this state, the hot air hits the material to be dried 1, and drying begins. The temperature of the hot air is detected by a temperature detection unit 20, and is adjusted to a temperature of 200° C. or lower at which organic matter does not decompose. With this heat, the material to be dried 1 begins to dry, and the air containing humidity circulates to the adsorption section 6.

The dry adsorbent 5 adsorbs moisture and does not generate adsorption heat. Therefore, the circulating air with low humidity and high humidity in the adsorption part 6 is changed to high temperature and dry air at the outlet of the adsorption part 6. The dried and heated air is again supplied to the storage chamber 2, and the material to be dried is dried even more quickly and more moisture is evaporated.

This moisture again generates adsorption heat in the adsorption section 6, which accelerates the amount of circulating heat and speeds up the drying of the material to be dried.

600 Kcal of heat is required to vaporize 1 Kg of water (When an adsorbent such as zeolite adsorbs the same amount of water vapor, it generates about 1000 Kcal of heat. Therefore, the heat generated in this entire system is equal to the amount of water I Kg transferred). The difference between 1000Kcal and 600Kcal is 400Kcal each time
It becomes l. As a result, this 400 Kcal and the calorific value of the heater 12 continue to be stored in the system.

As a general characteristic of adsorbents, the amount of adsorption tends to decrease as the temperature rises.There is a certain limit to the temperature rise of the adsorbent 5. The critical temperature in this example using zeolite is about 150°C.

This limit temperature changes depending on the thermal insulation state of the device and the rate of water generation. ``The temperature will not rise abnormally, and the material to be dried will not be decomposed or ignited.

The aforementioned calorie difference of 400 Kcal is consumed to compensate for the temperature increase until the entire system reaches this limit temperature and the heat radiation that inevitably occurs in this device, and to maintain this system at the limit temperature. If perfect insulation was used (which is unlikely), the temperature of the entire system would rise and the adsorption would stop midway, making it a mere steamer.Depending on the degree of insulation design, this heat loss may need to be compensated for by the heat of the heater 12. Conversely, it may be necessary to add a heat dissipation means to the adsorption section 6.

If the amount of circulating air is increased within a range where this temperature limit can be maintained, heat transfer to the dried material 1 will be improved, and the air within the dried material 1 will be dried, resulting in a faster drying rate. However, if the air volume is increased excessively, heat radiation will increase and the temperature will drop. Appropriate control of this blower 8 is performed by the temperature detection section 2.
This is done in response to a 0 signal.

As the drying progresses and the moisture content of the dried material 1 decreases, the amount of vaporization decreases and the temperature of the adsorption section 6 decreases. This temperature drop is also detected by the temperature detection unit 20. At this time, the amount of circulating air is reduced in order to maintain the temperature as high as possible.

The completion of drying of the material to be dried 1 is detected when the temperature of the temperature detection section 20 returns to the original temperature, that is, the temperature when there is no heat of adsorption.

In this state, the drying stage ends and the stage of regenerating and drying the adsorbent 5 begins. Valve 18 Valve 1617K Blower 8 is stopped Blower 13 is in operation Heater 12 is stopped Heater 14 is energized In this state, outside air is taken in by the blower 13 and turned into high temperature dry air by the heater I4 at the suction part 6 and is discharged from the valve 17 in the direction of arrow B. Odors contained in the exhaust gas are purified by the catalyst 22. In this case, the amount of air needs to be smaller than that of the blower 8 described above. This is because the adsorbent 5 is in the form of pellets and has good contact with air and dries easily, and if the amount of air is large, unnecessary air sensible heat will be released outside the device. This is because it will be done.

Furthermore, since the adsorbent 5 is nonflammable, it can be rapidly dried and regenerated using a small amount of hot air at a heat resistance limit temperature (for example, 500° C. for zeolite). The completion of dry regeneration is determined when the temperature of the temperature detection section 21 becomes approximately equal to the temperature of the hot air.

For dry regeneration, adsorbent 5 has a water adsorption amount of 100 kg per IKg.
It absorbs 0Kcal of heat. That is, at the end of dry regeneration, the adsorbent 5 has an adsorption interfacial heat storage of 1000 Kcal.

That is, in the first stage, the material to be dried is rapidly dried with high-speed circulating air with a large amount of heat at a medium-low temperature, and the moisture is transferred to the nonflammable adsorbent material 5, and in the second stage, the adsorbent material 5 is rapidly dried with high-temperature air. Regeneration Sum The amount of heat stored in the adsorbent 5 in the second stage is used to generate a large amount of heat in the first stage.

Furthermore, even if the direction of air flow in the adsorption section 5 is reversed between when drying the material to be dried and when drying the adsorbent 5, and the drying and regeneration time of the adsorbent 5 is shortened, the adsorbent 5 before drying and regeneration is The force that contains moisture from upstream in the input direction (when drying and regenerating this, if high-temperature regenerated air is flowed in the A direction, the moisture will flow in the A direction while repeating adsorption and desorption in sequence, and as it takes time, heat radiation will be intense) Electricity charges will be higher.On the other hand, when the flow direction is B direction during dry regeneration, the dry regeneration ends quickly because there is a moist adsorbent at the most downstream position.

Next Different embodiments of the present invention will be explained with reference to FIG. In FIG. 2, elements common to those in FIG. 1 are given the same numbers, and some explanations are omitted.

An air preheating path 23 is provided between the blower 13 and the heater 14 , and the air preheating path 23 is surrounded by an exhaust path 24 downstream of the catalyst 22 and an air preheating section 25 .

Here, when drying and regenerating the adsorption section 6, the valve 18 [A valve 16, 171A, blower 8 stop, blower 13 operating state and L, heater 12 stop, heater 13 in energized state, The air is taken in at 13 and exchanged with the heat of the exhaust air at the air preheating section 25 to raise the temperature. In the present invention, only a small amount of air is required for regeneration, and since the desorption temperature of the nonflammable adsorbent 5 is high, the small air preheating section 25 is
The exhaust heat is effectively recovered. The amount of current applied to the heater 14 is therefore reduced, and operating costs are significantly improved. It is also possible to shorten drying and regeneration time.

Effects of the Invention As described above, according to the present invention, it is possible to effectively utilize heat, dry the material to be dried in a short period of time without burning it, and realize a small, simple and practical drying device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention. FIG. 2 is a longitudinal cross-sectional view of another embodiment of the present invention. 1. Dried cabinet 2. Storage section, 6.. 5 Adsorption section, 8.
・Blower, 12... Heiku 14... Heiku 22...
Touching 25... Air pre-p4a

Claims (1)

[Scope of Claims] 1) A storage section for an object to be dried, a means for heating the object to be dried, an adsorption section having a nonflammable adsorbent that adsorbs vaporized moisture of the object to be dried, and heating of the adsorbent. an internal circulation path provided between the storage section, the suction section, and the blower; and an external air supply path through which external air circulates in the suction section; circulating air below the ignition temperature of the material to be dried whose temperature has been raised by heat of adsorption generated by the heating means and the adsorption section through the internal circulation path; and when drying and regenerating the adsorbent, the heating means A drying device that supplies high-temperature air that is higher than the ignition temperature of the generated material to be dried to the external air supply path to dry and regenerate the adsorbent. 2) The drying device according to claim 1, wherein the flow direction of the air flowing through the suction section through the external air supply path is opposite to the flow direction of the air flowing through the suction section through the internal circulation path. 3) The drying method according to claim 1, wherein a temperature detection section is provided upstream of the flow of the material to be dried in order to maintain the material to be dried at a predetermined temperature during drying, and the air volume of the internal circulation path is controlled to keep this temperature constant. Device. 4) Claim 1 having a function of determining the amount of adsorption heat generated from the temperature change of the temperature detection section and determining the end of drying based on this decrease.
Drying equipment as described. 5) An adsorption part temperature detection part is provided downstream of the adsorption part in the flow direction,
2. The drying apparatus according to claim 1, further comprising a function of determining the end of drying and regeneration of the adsorbent when the temperature of the adsorption part temperature detection part becomes substantially equal to the temperature of the hot air for drying and regeneration. 6) The drying apparatus according to claim 1, further comprising a deodorizing catalyst provided at the discharge section of the external air supply path. 7) Claim 1 further comprising a heat exchange section between external air upstream of the external air supply path and exhaust gas downstream of the external air supply path.
Drying equipment as described.