JPH0432685A - Drier - Google Patents

Abstract

PURPOSE:To enable drying with limited consumption of energy by utilizing sensible heat left in an adsorbent for the raising of temperature of material to be dried with quick drying and regeneration of the absorbent by a high temperature air. CONSTITUTION:Material 1 to be dried such as refuse or foods is fed onto a grid plate 4 at a housing section 2. A valve 18 is closed while valves 16 and 17 are opened and a blower 6 is stopped while a blower 13 is out into operation. A heater 12 is stopped upstream from the housing section 2. The heater 14 in an inflow path of an outside air to an adsorbing section 6 is energized. After the drying and regeneration of the absorbent 5, the valve 18 is opened while the valves 16 and 17 are closed and the blower 8 is put into operation while the blower 13 is stopped. In such a manner, the valves and the blowers are set and an internally circulated air flows to be heated by sensible heat of the adsorbent 5 heated up to 500 deg.C. No moisture is adsorbed while the adsorbent 5 is at a high temperature. When adsorption begins, the circulated air with a high moisture at an inlet of the absorbing section 6 is turned to air dried at an outlet of the absorbing section 6. Thus, the air dried is supplied to the storing chamber 2 again thereby permitting the evaporation of much more moisture from the material 1 to be dried with further speeding up of the drying.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a simple drying device for drying flammable materials such as kitchen waste, waste paper, human waste, and foods.

BACKGROUND ART In general, when drying kitchen waste, waste paper, human waste, food, etc., it is difficult to remove moisture contained in the dried material using mechanical separation means, and therefore heat drying is often used. For heating and drying, it is necessary to transfer the amount of heat equivalent to the latent heat of the water contained in the material to be dried, and the typical means for this heat transfer are convection heat use and radiant heat use.

Conventional drying apparatuses use these heat transfer means to heat moisture in the material to be dried and release water vapor.

Problems to be Solved by the Invention Incidentally, radiant heat is suitable for treating flat objects such as paint films and open fish, but when drying three-dimensional objects, it tends to cause unevenness and scorching, so it is difficult to treat organic materials. It was not suitable for drying.

Also, when vacuum drying under reduced pressure, radiant heat is often used as a heat source, but if you try to dry quickly, uneven drying tends to occur between areas exposed to radiation and areas that are naturally slow. .

Furthermore, the material to be dried generally has an unspecified shape, and when using radiant heat for drying, pretreatment such as crushing, cutting, and compression of the material is required, and the equipment tends to be large. .

On the other hand, a drying device using hot air as a heat source does not cause uneven drying as much as a drying device using radiation, so it is possible to dry the product in its original shape.

However, if hot air drying is used, the material to be dried can be dried relatively uniformly, but if the temperature is raised and the material is dried rapidly, if the material to be dried is organic, it will catch fire or burn. Therefore, it is necessary to dry at a temperature below the decomposition temperature of the organic matter, but if the temperature is too low, the drying time becomes longer.

Therefore, means are taken to dry the material using air at a temperature lower than the decomposition temperature of the organic matter.

In this case, increase the wind speed to improve heat transfer with the material to be dried,
In addition, means for promoting drying by reducing the humidity of the atmosphere of the material to be dried has been known for boat fishing.

In this method, a heat exchanger is installed between the exhausted air after drying and the air before drying to reduce operating costs by recovering heat. However, the efficiency of heat recovery from low-temperature, large-volume air is poor, and there is a problem in that the heat exchanger tends to be large.

When drying at high temperatures through combustion, a large amount of heat can be easily obtained and the fuel cost is relatively low, so this drawback is not a major disadvantage. However, drying equipment that uses electricity and is aimed at miniaturization has high energy costs. However, since the device is large, it has been difficult to realize a practical drying device.

The present invention has been made in consideration of the above-mentioned conventional problems, and an object of the present invention is to provide a small and simple drying apparatus capable of rapid drying, low energy drying, drying without burning the material to be dried, and effective use of heat.

Means for Solving the Problems In order to achieve the above-mentioned objects, the present invention provides an adsorption system having a storage section for drying material and a nonflammable adsorbent that adsorbs vaporized moisture from the drying material. a heating means for the adsorbent; an internal circulation path provided between the storage section, the adsorption section, and the blower; and an external air path through which external air circulates through the adsorption section; a first step in which external air is circulated through the adsorbent, and the adsorbent is heated by the heating means of the adsorbent to remove moisture already adsorbed by the material to be dried; After separation, the drying apparatus is configured to perform a second stage operation in which the air in the internal circulation path is circulated to transfer the moisture of the material to be dried to the adsorbent and generate heat by adsorption.

Furthermore, as a second problem-solving means, the first step and the twenty-eighth
The reason for this is that the drying device has at least two suction sections, each of which alternately performs the first and second stage operations, and furthermore, As a means for solving the problem of No. 4, a drying apparatus is provided with a heat exchange section between external air upstream of the air supply path and exhaust air downstream of the external air supply path.

Function: The drying device configured as described above heats the adsorbent in the adsorption section to remove moisture, sends the high-temperature air generated here to the storage section containing the material to be dried, and dries the material to be dried. let The moisture released from the dried material is circulated to the adsorption section, where it is transferred to and adsorbed by the adsorbent.

Example 1 of the present invention below. An example of the second problem solving means is
This will be explained based on the attached FIG. 1. In the figure, 1 is kitchen waste;
It is a product to be dried such as food. The material to be dried 1 is placed on a grid plate 4 inside a storage section 2 forming a chamber with a door 3. A non-combustible adsorbent 6 such as zeolite is placed on a grid plate 7 inside the adsorption section 6 forming a chamber. Upstream in the flow direction of the circulation blower 8 (hereinafter simply referred to as upstream and downstream)
is connected to the suction section 6 and the downstream side is connected to the storage section 2 through internal circulation paths 9 and 10, respectively, and the downstream side of the storage section 2 is connected to the upstream side of the suction section 6 through an internal circulation path 11. A drying heater 12 that generates heat when energized is provided in the internal circulation path 1o.

The air is circulating in the direction of arrow A in the figure.

The upper part of the suction part 6 is provided with a reed so that the air from the blower 13 for regeneration flows in, and a heater 14 for regeneration is installed in the inflow path.
is provided. And the flow direction is arrow B.

Further, an exhaust pipe 15 is connected to the lower part of the adsorption section 6.

Further, pulps 16, 17, and 18 are provided for switching each flow path. Furthermore, the main body of 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 6 is provided with a temperature detection section 21. Further, a catalyst 22 for purifying exhaust gas is provided near the pulp 17.

Next, the operation will be explained in detail.

Items to be dried 1 such as kitchen waste and food are placed onto the grid plate 4 of the storage section 2. The adsorbent 5 of the adsorption section 6 is still adsorbed with moisture from the previously processed dried material.

The pulp 18 is closed, the pulp 16.17 is opened, the blower 8 is stopped, the blower 13 is in operation, and the heater 12 upstream of the storage section 2 is turned on.
is stopped, and the heater 14 in the inflow path of external air to the suction part 6 is stopped.
is in the energized state. In such a first stage state, external air is taken in by the blower 13 and flows in the direction of arrow B, and is turned into high temperature dry air by the heater 14 and sent to the suction section 6. Since the adsorbent 5 is nonflammable, it can be rapidly dried and regenerated using hot air at a heat-resistant limit temperature (eg, SOO°C for zeolite). The adsorbent 5 is gradually heated and its temperature rises, but the adsorbed water does not desorb even when the temperature reaches 100°C, and the temperature remains between 3oo°C and 500°C.
(in the case of zeolite), the desorption of water increases rapidly. In this temperature range, the adsorbent 6 absorbs and absorbs heat from the high-temperature dry air while desorbing water.

Here, in order to deposit water IKs+M, 6 to 9 zeolite is required as an adsorbent, and this adsorption generates heat of 1000 d. Therefore, for dry regeneration, it is necessary to raise the temperature to 5 o
) and a heat of desorption of 10007 is required. At the end of drying, the adsorbent 5 has sensible heat of 750 d and adsorption interface heat storage of 10 oO1al, and the material to be dried 1 is in a state where it is not heated at all.

The desorption completion temperature is about 500°C. When this temperature is reached, the adsorbent 5 becomes almost dry. 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.

After the adsorbent 5 is dried and regenerated, the valve 18 is closed and the pulp 1
6.17 opened, 8 blowers running, 13 blowers stopped. The pulp and the blower are set in this way, and internally circulating air is flowed in the direction of the arrow and heated by the sensible heat of the adsorbent 5, which is heated to 60°C.

The object to be dried 1, the storage chamber 2, and the internal circulation paths 9 and 10 are heated with the heated circulating air. Moisture vaporized from the material to be dried 1 by this heating circulates to the adsorbent 5, but no moisture is adsorbed while the adsorbent 5 is at a high temperature.

Adsorption begins after the temperature of the adsorbent 5 has decreased. Generally, the adsorption amount of the adsorbent 5 tends to increase as the temperature decreases, so there is a certain limit to the temperature reduction of the adsorbent 6, and in this example using zeolite, the limit temperature is 100°C. there were. Although this limit temperature changes depending on the heat insulation state of the device and the rate of moisture generation, the adsorbent 5 maintains its own temperature above a certain level by adsorption and heat generation.

When adsorption begins, the highly humid circulating air at the suction part 6 changes to dry air at the suction part 6. Since dry air is supplied to the storage chamber 2 again, the material to be dried 1 dries more quickly and evaporates more moisture. This water causes the adsorption unit 6 to generate adsorption heat again, which increases the amount of circulating heat at an accelerated pace and speeds up the drying of the material 1 to be dried.

In the above, to vaporize water at IK9100℃,
ical/h of heat is required, but adsorbents such as zeolite reduce the heat of adsorption by approximately 100 m
01at1 occurs. Therefore, the heat generation in this entire system is 46 times the difference between 1000W and 540d for every 9 movements of water 1.
It becomes 01al. This 4 eohl is consumed to compensate for the heat dissipation that inevitably occurs in the device and to maintain the system at the required temperature.

Depending on the degree of insulation design, it may be necessary to compensate for this heat radiation loss with the heat of the heater 12.

If the amount of circulating air is increased within a range where the temperature suitable for the object to be dried can be maintained, heat transfer to the object to be dried 1 will be improved, and since the air within the object to be dried 1 will be dried, the drying speed will be increased. However, excessive increase in air flow increases heat dissipation from the entire system, leading to a drop in temperature. The temperature is measured by the temperature detection section 2o, and the blower 8 is appropriately controlled to maintain the optimum temperature.

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 section 20, but at this time, the amount of circulating air is reduced in order to maintain the temperature as high as possible.

Completion of drying of the object 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.

Furthermore, the direction of air flow in the adsorption section 6 is reversed between when drying the adsorbent 5 and when drying the object 1 to be dried, thereby shortening the drying and regeneration time of the adsorbent 5.

In other words, the adsorbent 5 before dry regeneration contains moisture from upstream in the input direction, but when high-temperature regenerated air is flowed in the input direction when drying and regenerating it, moisture is absorbed and desorbed sequentially in the input direction. Not only does it take a long time to flow, but it also dissipates heat and increases electricity bills. 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.

Further, the amount of adsorbent 6 may be less than the amount that adsorbs all the water content of the material to be dried 1. In this case, the first stage ends quickly because the amount of adsorbent 5 is small. The second stage also ends early because the adsorption stops progressing. Next, the process is repeated again from the first step, but since the temperature of the entire device has risen, the power required from the second time onwards can be saved.

Moreover, during the first stage from the second time onward, hot air is not supplied to the object to be dried 1, but the moisture inside the object to be dried 1 continues to migrate to the surface, so that the drying time can be substantially shortened. In this case, the operation ends in the second stage.

In the above embodiment, the number of suction sections 6 is half one, but as a third means to solve the problem, there are a plurality of suction sections 6, and the drying time is further shortened by repeating the first stage and the 28th stage alternately. It is also possible to do so.

Next, the fourth problem solving means will be explained with reference to FIG.

The characteristic configuration of this embodiment is that, in the basic configuration of the previous embodiment, an air preheating path 23 is provided between the blower 13 and the heater 14, and the air preheating path 23 is surrounded by a catalyst 22.
The downstream exhaust path 24 is the air preheating section 25.

With this configuration, in the first stage of dry regeneration of the adsorption section 6, the valve 18 is closed, the valve 18.17 is opened, the blower 8 is stopped, the blower 13 is in operation, the heater 12 is stopped, and the heater 14 is in operation.
is in the energized state. In this state, external air is taken in by the blower 13, and is heated to a high temperature by exchanging heat with the exhaust air in the air preheating section 25.

In this embodiment, only a small amount of air is blown for regeneration, and since the desorption temperature of the nonflammable adsorbent 5 is high, exhaust heat can be effectively recovered in the small air preheating section 25. The amount of current applied to the heater 14 is therefore reduced, and operating costs are significantly improved. It is also possible to shorten the drying and regeneration time.

As is clear from the description of each embodiment above, the first role of the present invention is to rapidly dry and regenerate the adsorbent with high-temperature air.
The second stage is the first stage ←+ (The sensible heat remaining in the adsorbent is used to raise the temperature of the material to be dried, making it possible to dry with less energy consumption. It has the advantage that there is no problem with drying even when the adsorbent becomes moist.Also, the latent heat of the steam is recovered by the adsorbent, making effective use of heat. It is possible to dry the material to be dried in a short period of time without burning it with air, and it is possible to realize a small, simple and practical drying device.

[Brief Description of the Drawings] Fig. 1 is a vertical cross-sectional view of a drying device according to an embodiment of the present invention;
The figure is a cross-sectional view of the drying device of the example in the same place. 1...--To be dried, 2... Storage section, 5...
...Adsorption material, 6...Adsorption part, 8...
...Blower, 12... Heater, 14...
・Heater, 22...Catalyst.

Claims (4)

[Claims] (1) Between a storage part for the material to be dried, an adsorption part having a nonflammable adsorbent that adsorbs moisture in the material to be dried, heating means for the adsorbent, and a space between the storage part, the adsorption part, and the blower. an internal circulation path provided, and an external air path through which external air circulates in the adsorption section, the external air path is circulated through the external air path, and the adsorbent is heated by the heating means of the adsorbent to dry the material to be dried. The drying apparatus operates in a first stage in which moisture adsorbed by the material is desorbed, and in a second stage in which air in an internal circulation path is circulated to transfer and adsorb moisture from the material to be dried. (2) Start operation from the first stage, and then proceed to the second stage and the first stage.
2. The drying apparatus according to claim 1, wherein after the stages of operation are performed alternately, the operation is ended upon completion of the second stage. (3) Claim 1, wherein at least two adsorption units are provided in parallel, and the first stage and second stage operations are performed alternately.
Drying equipment as described. (4) The drying apparatus according to 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.