JP2690172B2 - Heat exchange device for powdery particles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat exchange device. More specifically, the present invention relates to a high-performance small-sized heat exchange device for heating, cooling, or drying powder or granules by a solid-gas multiphase flow.

(Prior Art and Its Problems) Conventionally, a fluidized bed type heat exchange device has been known in which heat is exchanged while suspending a powder or granular material with a gas or the like for the purpose of heating, cooling or drying the powder or granular material ( "Encyclopedia of dried food" [Asakura Shoten] (1984), 83-84).

FIG. 2 and FIG. 3 are schematic cross-sectional views illustrating such a conventional fluidized bed heat exchange device. In any of these conventional heat exchange devices, the powdery or granular material is placed on the perforated plate (a) provided in the lower part of the device, and a gas is blown from the lower part of the device by an air blower (not shown) in the direction of the arrow. After the particles are suspended to form a fluidized bed (a), as shown in Fig. 2, between the heat transfer tube (wa) and the particles, or gas and particles as shown in Fig. 3. The feature is that heat is exchanged between them. A heat exchange device that vibrates the perforated plate (a) at that time has also been proposed. However, even in that case, the vibration of the perforated plate (a) is also used as energy for forming the fluidized bed (a), and the basic principle and configuration are the same as those of the above-mentioned device.

Generally, the concept of fluidized bed is, in a broad sense, a spouted bed, a transport layer,
Although a thin layer is included, the fluidized bed in a narrow sense represented by the above conventional apparatus (hereinafter simply referred to as a fluidized bed) has extremely good heat transfer between particles and gas due to vigorous movement of powder flow material. In addition, the heat transfer coefficient between the fluidized bed and the heat transfer wall is extremely large, and it is easy to insert the heat exchanger into the bed.

However, in such a conventional heat exchange device, since a suitable flow area is required for the powder particles to flow well, the installation area of the device becomes vast and a fluidizing gas is generated. For this reason, additional facilities such as a blower facility, an exhaust facility, and a dust collecting facility are required, so that the investment amount and running cost are high, and there is an industrial defect that maintenance is poor.

Of course, many inventions have been made to improve the heat transfer efficiency of this conventional heat exchange device.
The main one is to devise the shape of the heat exchanger to be inserted inside, and the one to devise the mixing and disturbance of the particles in the bed, and it has not been able to eliminate the above-mentioned inherent defects of the fluidized bed.

On the other hand, in addition to these heat exchange devices, a moving bed heat exchange device has also been proposed, in which heat is exchanged while applying vibration to the thrust lamination of the powder and granules (Japanese Patent Publication No. 63-59077, Japanese Patent Laid-Open No. 5197/1987).
8-136986). It is true that this moving bed does not require much space as compared with the fluidized bed, so that the moving bed heat exchange device generally has the advantage of being easy to miniaturize. However, in the case of heat transfer by this moving bed, since the mixing of particles is bad, a temperature distribution occurs in the bed especially when the bed height is high, and the heat transfer performance between the moving bed and the wall is not that of the fluidized bed. It does not reach at all. Therefore, the moving bed heat exchange device is significantly inferior to the fluidized bed heat exchange device in terms of heat transfer performance.

In addition, gas containing a small amount of solid particles (for example, waste incinerator flue gas, waste gas emitted from kilns, waste gas produced by metal smelting, gas containing media and dust, industrial nitrogen combustion furnace exhaust gas, etc.) In a heat exchanger for exchanging heat with a heat absorbing medium as a heat radiating medium, a device for purifying a heat transfer surface by vibrating or impacting a heat transfer tube is disclosed in Japanese Examined Patent Publication No. 56-33629. -159598, JP-A-56-82395, JP-B-56-8957, etc. have already been disclosed,
The vibration and impact methods include using a drop mallet, using an eccentric plate and the top and bottom due to gravity, using a pneumatic cylinder, impacting the link chain against the wall surface.
Many things are known, such as those that induce vibration and those that generate ultrasonic vibration by providing a jet nozzle and a resonator. However, even though these heat exchangers contain solid particles, they are essentially for gas, and solids in gas are not for heat transfer operation. That is, the main body of heat exchange in these devices is gas, and the trace amount of solid matter contained therein can only have the meaning of an inhibitory factor for heat transfer.Therefore, the application range is naturally limited to the case where the solid content concentration is trace amount. Limited. Therefore, in the essential sense, it cannot be used at all as a heat exchange device for powder and granules.

Other equipment that puts the granules in a rotating drum and heats or cools them while rolling them, a device that heats or cools them while stirring the granules layer with a stirrer, and put the granules on a belt conveyor with hot air or Many types are known, such as a device that heats or cools with cold air, or a device that puts powdered or granular material on a tray and puts it in an oven or a small chamber to heat or cool it with hot air or cold air. However, it was not sufficient in terms of ease of management, certainty, hygiene, and safety.

The present invention has been made in view of the circumstances as described above, while maintaining the good heat transfer efficiency of the conventional heat exchange device, and eliminating the drawbacks thereof, high performance, and small gas It is an object of the present invention to provide a heat exchange device suitable for transported powder and granules.

(Means for Solving the Problem) As a solution to the above-mentioned problems, the present invention provides a part of a pipeline through which a solid-gas multiphase flow composed of a powdery substance and a gas and related to gas transportation of the powdery substance flows. , Arranging a casing containing a heat exchange main body, mounting a vibrating device for vibrating and / or impacting the heat exchange main body and / or the casing, and a solid-gas multiphase flow introduced from a pipeline passes through the casing. At this time, the heat exchange device for the powdered granules to be transported by gas, characterized in that the powdered granules are heat-exchanged while being vibrated and / or shocked by a vibrating device, and are discharged to the pipeline as a solid-gas multiphase flow. I will provide a.

In addition, in the heat exchange device of the present invention, it is also preferable that the cross-sectional area of the casing is within 2000 times the cross-sectional area of the conduit.

Hereinafter, with reference to the accompanying drawings, a configuration and an operation effect of the heat exchange device of the present invention will be described in detail.

FIG. 1 (a) is a schematic sectional view showing an embodiment of the heat exchange device of the present invention, and FIG. 1 (b) is shown in FIG. 1 (a).
3 is a sectional view taken along line AA ′ of FIG.

For example, as illustrated in FIG. 1 (a), in the heat exchange device of the present invention, a casing (4) containing a plurality of heat transfer tubes (3) is connected between the pipe lines (1) and (2). To do. The casing (4) is further provided with an exciter (5) for vibrating and / or impacting the casing (4) and / or the heat transfer tube (3), and heats the heat transfer tube (3). Flexible tubes (6) and (7) for introducing the medium and discharging the medium are connected.

Further, in the example shown in FIG. 1 (a), in order to maintain the safety of the entire device against vibration of the casing (4),
A flexible hose (8) is interposed at a connecting portion between the pipelines (1) and (2) and the casing (4), and further, the casing (4) is fixedly held on a support base (10) via a spring (9). ing.

For example, when heating or cooling the powder or granules by the heat exchange device having the above configuration, first, the powder or granules are introduced into the pipe (1) as a solid-gas multiphase flow with gas, and the solid-gas multiphase flow is introduced. When the powder passes through the casing (4), the powdered particles contained therein are heat-exchanged and discharged from the conduit (2).

The heat exchange, that is, the heat exchange, between the powder and granules inside the casing (4) is performed by indirect heat transfer between the gas and the powder and granules, and directly between the surface of the heat transfer tube (3) and the powder and granules. It is performed by contact heat transfer.

In the heat exchange device of the present invention, in particular, by effectively utilizing direct contact heat transfer, it is intended to reduce the size and performance of the device. The heat transfer effect decreases, and when the concentration falls below a certain level, the effect completely disappears. For example, when gradually lowering the concentration of the particulate matter in the mixed-phase flow to be introduced, when the ratio of the mass flow rate of the particulate matter to the gas becomes 0.01 or less, the heat transmission rate becomes almost the same as in the case of a simple gas heat exchange device, The significance of the heat exchange device for powder and granules, which is the object of the present invention, is lost. Therefore, the solid concentration of the solid-gas mixed phase flow introduced into the heat exchange device of the present invention is preferably such that the ratio of the mass flow rate of the powdery particles to the gas is at least 0.01 or more in terms of heat exchange efficiency. In addition, there is an upper limit of the solid concentration that can maintain the situation for this solid-gas multiphase flow. Although the range varies depending on the type of powder or granule, if the ratio of the mass flow rate of the powder or granule to the gas is 1000 or less, a multiphase flow with a good flow state can be generally obtained. Therefore, in the heat exchange device of the present invention, it is preferable to introduce into the casing (4) a solid-gas mixed-phase flow having a mass flow rate of gas to powder gas in the range of 0.01 to 1000.

On the other hand, when this device is used for a solid-gas multiphase flow particularly related to gas transportation of powdery particles, the solid-gas multiphase flow carries gas inside the pipelines (1) and (2). In addition to the heat exchange efficiency, it is necessary to consider the gas transportation efficiency inside the pipelines (1) and (2). From the viewpoint of this gas transportation, it is generally desirable to introduce into the conduit (1) a solid-gas multiphase flow having a mass flow rate of 0.5 to 300 in the mass flow rate of the powdery or granular material.

Furthermore, the structure and configuration of the casing (4) are also important requirements for efficiently exchanging heat in such a solid-gas mixed-phase flow. For example, as shown in FIG. 1, a casing (4) arranged between the pipelines (1) and (2).
It is effective and preferable to enlarge the cross-sectional area thereof than the cross-sectional areas of the pipelines (1) and (2). By increasing the cross-sectional area of the casing (4) to be larger than the cross-sectional areas of the pipelines (1) and (2), the velocity of the gas in the solid-gas multiphase flow is reduced, and the retention state of the powder and granules is generated. The particle concentration inside the casing (4) can be increased. As a result, the efficiency of indirect heat transfer between the gas and the granular material inside the casing (4) and direct contact heat transfer between the surface of the heat transfer tube (3) and the granular material can be further improved. .

It should be noted that increasing the particle concentration inside the casing (4) should be avoided in the case of "a case where a heat-dissipating medium which is a substantially gas containing a small amount of solid particles" is cited as the prior art. That is, it is based on the technical idea which is completely opposite to that of the heat exchange device of the present invention.

Other than the above, as a method of increasing the particle concentration, a method of increasing the resistance by making the cross-sectional area of the casing (4) narrower than that of the pipe (1) and causing retention of particles, and the heat exchange body It is also possible to adopt a method in which the shape of the heat transfer tube (3) used as is devised so as to gently block the flow of particles and cause the particles to stay. In the former case,
If the cross-sectional area of the casing (4) is less than 1/10 of the cross-sectional area of the pipelines (1) and (2), the flow of the powder and granules is hindered, so it is preferable that the cross-sectional area be more than that. However, as a method for increasing the particle concentration, it is convenient and efficient to increase the cross-sectional area of the casing (4) so as to exceed the cross-sectional areas of the pipelines (1) and (2) as described above. . The larger the ratio of the cross-sectional area of the casing (4) to the cross-sectional area of the pipelines (1) and (2), the more the particle retention amount increases, and the heat exchange rate improves. However, when the ratio is too large, the flow state of the particles deteriorates. Therefore, the effect of vibration due to the vibration exciter (5), which will be described later, is also reduced. For example, even if extremely light particles are made to flow, if the expansion ratio of the cross-sectional area exceeds 2000 times, the effect of vibration can hardly be exhibited. Therefore, pipelines (1) and (2)
The range of enlarging the cross-sectional area of the casing (4) with respect to the cross-sectional area of is 1 to 2000 times, more preferably 1 to 1000 times. The magnification depends on the physical properties of the target powder and granules, such as the size, shape, and specific gravity of the particles, the density of the powder and granules in a solid-gas multiphase flow, and the setting conditions such as the flow rate of gas to be transported and the flow velocity. The optimum range (magnification) can be selected.

It is most preferable that the casing (4) is connected to the pipe lines (1) and (2) so that the solid-gas mixed phase flow is almost vertical, but the mixed phase flow may be horizontal or inclined. it can.

The heat exchange main body disposed inside the casing (4) may be, for example, a multi-tube type or coil type heat transfer tube (3) whose arrangement is illustrated in FIG. A heat fin, a heat transfer plate, etc. can be used, and the number, arrangement, shape, etc. thereof can be arbitrarily selected according to the conditions. Further, the inner wall surface of the casing (4) can be directly used as a heat exchange main body by forming the wall surface of the casing (4) into a double structure and flowing a heat medium in the middle portion thereof. Further, the heat exchange rate can be further improved by disposing a rectifying blade or the like for equalizing the flow of the powder or granules in the preceding step of the heat exchange section.

The vibrating machine (5) arranged in the casing (4) vibrates and / or impacts the casing (4) and / or the heat transfer tube (3) inside the casing (4) to increase the powder concentration. Prevents aggregation or solidification of the particles, improves the fluidity of the particles, and improves heat transfer efficiency.
That is, the particles contact the heat transfer tube (3) during the heat exchange, but at this time, the particles and the surface of the heat transfer tube (3) repeat contact and dissociation instantaneously due to the vibration of the vibrator (5). Such a disturbance occurs and effectively destroys the temperature boundary layer on the heat transfer surface. Therefore, the overall heat transfer coefficient inside the casing (4) increases dramatically.

Actually, for example, when the heat exchange of the skimmed milk powder was performed using the heat exchange device illustrated in FIG. 1 (a), the measured heat transfer rate was 34.2 Kcal / m ² · hr · ° C without vibration. It was improved to 64.9Kcal / m ² · hr · ° C by moderate vibration. As described above, in the heat exchange device of the present invention, the heat transfer effect is improved while maintaining the extremely high particle density and the degree of mixing similar to those of the conventional fluidized bed heat exchange device, so that the heat transfer tube (3) is compact. It has a small capacity and enables efficient heat exchange.

The vibrator (5) arranged in the casing (4) is
Various well-known devices that can apply vibration and / or shock continuously or intermittently can be used. An electric rotary vibrator having an eccentric weight attached to the shaft of the motor, or an air knocker that reciprocates the piston at high speed with magnetic force and compressed air is preferable, but is not limited to this. Also, the vibration direction, strength, frequency, etc. of the vibration exciter (5) can be arbitrarily selected according to the conditions. It is also possible to switch to vibration or shock at intervals, and to use continuous vibration and intermittent vibration together. Furthermore, various connection methods are available for the shaker (5), the casing (4), and the heat exchange body. For example, in the case of the example shown in FIG. 1 (a), the vibrator (5) is directly connected to the casing (4) and the heat transfer tube (3), and the casing (4) and / or the heat transfer tube (3) is connected. Although a method for giving uniform vibration to the casing is adopted, for example, a shaker (5) is attached to another support, and vibration or impact is given to the casing (4) and / or the heat exchange main body via a rod. The mechanism and / or each part of the device may be separately or only partly vibrated or impacted.

As described above, the heat exchange device of the present invention realizes excellent effects that cannot be achieved by the conventional heat exchange device. Actually, the heat exchange device illustrated in FIG. 1 (a) was prototyped as a milk powder cooler, and as a result of operating and operating the device, the size of the device was larger than that of a conventional fluidized bed cooler under the same capacity and the same cooling conditions. Approximately 1/20, installation area is approximately 1 /
36. It was confirmed that the running cost was about 1/63 with electricity alone.

Of course, the heat exchange device of the present invention is not limited to the above examples, and it goes without saying that the configuration and structure thereof have various modes.

(Effects of the Invention) As described in detail above, according to the present invention, 1) a heat exchange device having a heat transfer performance equal to or higher than that of a conventional fluidized bed heat exchange device, and having a simple structure and small size. Can be provided.

2) It will be possible to reduce equipment costs and running costs.

3) Further, since the structure is simple, it is possible to achieve industrial advantages such as maintenance and inspection, durability, cleanability, and high yield of powder and granules.

4) Further, since the powdery or granular material can be continuously treated during the gas transportation, it is most suitable as a heat exchange device for the powdery or granular material to be gas-transported.

5) Moreover, since the entire device is a closed system, it is possible to treat the gas and powders used without contacting with the outside air.
It can also be applied to dry powder. In addition to the safety management, hygiene management is extremely good when the powdered material is food.

[Brief description of the drawings]

1 (a) is a schematic sectional view showing an embodiment of the heat exchange device of the present invention, and FIG. 1 (b) is a sectional view taken along the line AA 'in FIG. 1 (a). 2 and 3 are schematic explanatory views showing an example of a conventional heat exchange device. 1 ... Pipe 2 ... Pipe 3 ... Heat transfer tube 4 ... Casing 5 ... Vibrator 6 ... Flexible tube 7 ... Flexible tube 8 ... Flexible hose 9 ... Spring 10 ... Support base

Claims (2)

(57) [Claims] 1. A casing containing a heat exchange main body is provided in a part of a pipe line made of powder and granules and a gas in which a solid-gas multiphase flow relating to gas transport of the powder and granules flows. / Or a casing is provided with a vibrating device that vibrates and / or impacts, and when the solid-gas multiphase flow introduced from the pipe passes through the casing, the vibrating device vibrates and / or impacts the powder containing powder. A heat exchange device for gas-transported powder and granules, which heat-exchanges the granules and discharges them into a pipe as a solid-gas multiphase flow. 2. The cross-sectional area of the casing is 2000 times that of the pipeline.
The heat exchange device for gas-transported powder and granules according to claim 1, wherein the heat exchange device is in the range of not more than double.