JP3636588B2 - Drying equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drying apparatus that forms a drying processing section inside a porous partition wall, jets a drying heating gas from the outside to the inside of the porous partition wall, and performs a drying process on an object to be processed in the drying processing section. .
[0002]
[Prior art]
Conventionally, as this type of drying apparatus, for example, as shown in FIG. 3, a drying processing unit 2 is formed as a flow path having at least one opening 10 instead of a closed space inside a cylindrical porous partition wall 1. From the outside of the porous partition wall 1, the heating gas for drying heated at a location away from the porous partition wall 1 is pressurized and supplied to the outer wall surface side of the porous partition wall 1 through the heating gas supply pipe 11 for drying. The droplets of the workpiece 3 sprayed from the spray mechanism 6 provided in the drying processing unit 2 directly contact with the heating gas for drying sprayed through the porous partition wall 1 and evaporated. There was one that was configured to be discharged and collected through the opening 10 on the carrier flow of the heating gas for drying while evaporating the components. For example, a solids separating and drying apparatus disclosed in Japanese Patent Application No. 9-55855 corresponds to this.
Further, in this conventional drying apparatus, since the drying heating gas is supplied with the flow rate sufficiently suppressed by the porous partition wall 1, the solid matter after the evaporation component has evaporated is transferred to the drying processing unit. After being discharged to the outside, it has a structure in which it is naturally separated without falling on the heating gas flow for drying and easily separated and recovered. Moreover, the heating gas for drying after the drying process was also discharged through the opening 10, and after the solid was separated, the exhaust gas was separately exhausted. In this exhaust processing, when the drying heating gas is superheated steam, it is cooled and liquefied and recovered, and when the drying gas is heating air, it is discharged into the atmosphere as it is.
In addition, in FIG. 3, the common code | symbol is used about the part which is common in the thing of the drying apparatus which concerns on this invention among the codes | symbols of each part.
[0003]
[Problems to be solved by the invention]
However, in the conventional drying apparatus, there may be a case where the distance between the place for heating the heating gas for drying and the drying processing unit 2 becomes long, and the drying processing unit is radiated from the drying heating gas supply pipe 11 by heat radiation. There was a possibility that the temperature when jetted into the nozzle 2 was lowered and the drying efficiency was lowered.
The present invention has been made in view of such problems, and the object thereof is to solve the above problems and prevent a decrease in the temperature of the drying heating gas that is jetted into the drying processing unit 2. An object of the present invention is to provide a drying apparatus capable of increasing the temperature inside the drying processing unit 2 and improving the drying efficiency.
[0004]
[Means for Solving the Problems]
In order to achieve this object, the first characteristic configuration of the drying apparatus according to the present invention is that, as described in claim 1 of the appended claims, a drying treatment section is formed inside the porous partition wall, A drying apparatus that sprays a heated gas from the outside to the inside of the porous partition wall to dry the object to be processed in the drying processing unit, and sprays the object to be processed upward in the drying processing unit. A spray mechanism is provided at a lower part of the drying processing unit, an opening for discharging the processed material after the drying processing is provided at an upper end portion of the drying processing unit, and heating means for heating the porous partition is provided. It is in.
[0005]
In the second feature configuration, in addition to the first feature configuration, the porous partition wall is made of a magnetic metal, and the heating means is the porous feature, as described in claim 2 of the column of claims. This is an induction heating means for generating an induced current in the partition wall.
[0006]
The third characteristic configuration is that, in addition to the first or second characteristic configuration, the heating gas for drying is superheated steam as described in claim 3 in the column of the claims.
[0008]
In the fourth feature configuration, in addition to the first, second, or third feature configuration, the porous partition wall is formed by hot isostatic pressing, as described in claim 4 in the appended claims. It is in the point formed with the porous metal sintered compact formed by the sintering.
[0009]
The operation and effect will be described below.
According to the first characteristic configuration, the drying heating gas whose temperature has been reduced by heat radiation or the like is heated when passing through the porous partition wall heated by the heating means, and the temperature decrease can be compensated. It is. Further, when the porous partition wall is not actively heated regardless of this feature configuration, the temperature in the drying processing unit is determined solely by the effect of radiant heat and convection from the drying heating gas jetted into the drying processing unit. However, the temperature does not exceed the temperature of the heating gas for drying, and the temperature of the vaporized heat decreases due to heat exchange with the object to be processed and evaporation of the evaporation component of the object to be processed. According to this, the inside of the drying processing section can be directly heated from the porous partition wall, the temperature inside the drying processing section can be made higher than the heating gas temperature for drying, and as a result, the drying efficiency of the object to be processed is improved. It can be done.
Furthermore, according to the first characteristic configuration, the droplets of the object to be processed are atomized, the specific surface area is increased, the contact efficiency with the heating gas for drying is increased, evaporation is promoted, and the drying processing capacity is increased. Improvement can be achieved. As a result, the apparatus can be miniaturized.
[0010]
According to the second characteristic configuration, the induction heating means induces an eddy current in the porous partition made of magnetic metal by generating a magnetic field, and directly heats the porous partition by the eddy current. By arbitrarily adjusting the magnetic field strength distribution in the wall surface of the porous partition wall, the inside of the porous partition wall can be heated to an arbitrary temperature distribution, and the temperature distribution in the drying treatment section can be optimized. As a result, the drying efficiency can be improved.
Further, since the induction heating means does not need to be in close contact with the porous partition wall, a gap for conveying a drying heating gas can be secured between the induction heating means and the porous partition wall, and the induction heating means In addition, since the processing for securing the heating gas conveying passage for drying is unnecessary for the porous partition wall, the induction heating means can be easily installed.
[0011]
According to the third characteristic configuration, since the evaporation component and superheated vapor of the object to be processed are generally liquid at normal temperature, they are liquefied by cooling in the recovery process when exhausting the heating gas for drying after drying. Since it is possible to condense and discharge a large amount of exhaust gas as a liquid having a reduced volume, the apparatus can be miniaturized.
Moreover, since the superheated steam has a large heat capacity among the heating gas for drying, the heating efficiency of the object to be processed can be increased.
Further, when the superheated steam is superheated steam, the superheated steam is excellent in explosion-proof property and non-oxidation property, and the surplus superheated steam can be recovered as water, so that there is an advantage that handling after recovery becomes easy.
[0013]
According to the fourth characteristic configuration, first, the porous partition wall is given sufficient strength by the porous metal sintered body and can withstand high temperatures, so that it is possible to supply a heating gas for drying at a high temperature and a high pressure. In addition, since the pore diameter of the porous metal sintered body can be reduced, in the case of a heating gas for drying, particularly in the case of superheated steam, the flow rate can be suppressed, and the contact time between the heating gas for drying and the droplet of the object to be treated That is, contact efficiency can be improved and heating efficiency is improved. Furthermore, the porous metal sintered body formed by hot isostatic pressing is controlled to the pore diameter and its distribution, which is much larger than the ordinary sintered body in the continuous vent ratio. It is possible to further improve the efficiency of the drying process by making the contact of the droplets to be processed with the heating gas for drying more effective in the drying processing section.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a drying apparatus according to the present invention (hereinafter referred to as the present apparatus) will be described with reference to the drawings.
As shown in FIG. 1, the device of the present invention has a hollow cylindrical shape with a vertical axis in the vertical direction, and a vertical axis provided in the drying container 7 without contacting the inner wall 7a. A cylindrical porous partition wall 1, heating means 4 for heating the porous partition wall 1 provided on the outer periphery of the porous partition wall 1, and a drying process formed inside the porous partition wall 1. It is comprised from the spray mechanism 6 which sprays the to-be-processed object 3 toward the inside of the part 2 from the downward side.
[0015]
Further, an air supply port 7b for supplying a heating gas for drying into the drying container 7 is provided at a lower portion of the drying container 7 so that the drying heating gas after the drying process and the object to be processed 3 are placed in the drying container 7. A discharge port 7c for discharging from the top is provided in the upper part of the drying container 7, respectively. In addition, the upper end of the porous partition wall 1 and the inner side of the porous partition wall 1 are supplied so that all of the heating gas for drying supplied into the drying container 7 passes through the porous partition wall 1 and is supplied into the drying processing unit 2. An annular inner partition wall 8 is provided between the wall 7a, and a bottom member 9 that is constricted downward from the lower end of the porous partition wall 1 is provided to shield the lower opening of the porous partition wall 1. It is.
Accordingly, the heating for drying is performed through the air supply port 7b into the space outside and below the porous partition wall 1 in the drying container 7 defined by the porous partition wall 1, the inner partition wall 8, and the bottom member 9. The object to be processed 3 supplied with gas and dried in the drying processing unit 2 is sucked from the exhaust processing unit 14 provided with the drying heating gas after the drying process and exhausted. It rises on the carrier air flow toward the outlet 7c, is discharged to the outside through the opening 10 at the upper end of the porous partition wall 1 and the space above it, and is separated and collected by the separation and collection unit 13 It is configured as follows.
[0016]
The porous partition wall 1 is made of a porous metal sintered body having an average air hole diameter of about 70 μm and an air hole ratio of about 30% by controlling the hole diameter and its distribution by hot isostatic pressing. It consists of ferritic stainless steel, which is a metal magnetic material.
[0017]
The heating means 4 energizes the induction coil with a high frequency current to generate a high frequency magnetic field across the porous partition wall 1 to generate an eddy current in the porous partition wall 1, and the porous partition wall 1 is heated by the eddy current. It is comprised as the induction heating means 5 to do. The induction coil is housed in a suitable protective container so as to be insulated from the drying gas. The induction heating means 5 is arranged in a cylindrical shape over the entire outer periphery of the porous partition wall 1 inside the inner wall 7a in order to uniformly heat the porous partition wall 1 over the entire periphery. In order not to disturb the supply of the heating gas for drying to the outer wall of the porous partition wall 1, a gap that can secure the flow path of the heating gas for drying is provided without being in close contact with the outer wall. is there.
In the present embodiment, as will be described later, since the spray mechanism 6 is installed in the lower part of the drying processing unit 2, the drying process is concentrated in the lower part and the temperature distribution in the drying processing unit 2 is reduced. Since the lower portion tends to be lower, the induction coil is provided so as to be denser toward the lower portion. Further, the induction coil may be divided into a plurality of upper and lower sections, and the high-frequency current to be energized for each section may be increased toward the lower part.
[0018]
The spray mechanism 6 penetrates the workpiece supply pipe 6 a for supplying the workpiece 3 through the center of the bottom surface of the drying container 7 and the center of the lower end portion of the bottom member 9 from the outside of the drying container 7. A nozzle 6b is provided so as to extend upward in the drying processing unit 2 and to spray the workpiece 3 upward at the tip thereof.
[0019]
In the present embodiment, superheated steam generated by overheating with a super heater 12 provided outside the drying container 7 is used as the drying heating gas. The super heater 12 and the air supply port 7b are connected by a drying heated gas supply pipe 11 for conveying and supplying the superheated steam.
[0020]
Hereinafter, the operation of each part of the device of the present invention will be described.
The superheated steam that is the heating gas for drying is superheated by the super heater 12, is pressurized and supplied in the drying container 7 through the heating gas supply pipe 11 for drying and the air supply port 7b, and further the porous It is supplied into the drying processing unit 2 through the partition wall 1. Here, since the flow rate of the pressurized superheated steam is suppressed when passing through the porous partition wall 1, the droplets of the workpiece 3 sprayed from the nozzle 6 b in the drying processing unit 2 and In addition, since the heat capacity of the superheated steam is large, the drying processing efficiency can be increased, and the volume of the drying processing unit 2 and the drying container 7 can be reduced accordingly, and the apparatus can be downsized. Can be achieved. Further, since the object to be treated 3 is sprayed upward from the nozzle 6b, the residence time in the drying processing unit 2 can be secured for a longer time, and still become minute droplets. Since the contact area with the gas is effectively increased, the efficiency of heat exchange with the heating gas for drying, that is, the drying efficiency can be improved.
[0021]
The temperature and pressure conditions of the superheated steam in the drying container 7 are, for example, about 120 ° C. to 300 ° C. and about 200 kPa depending on the properties of the workpiece 3 and the processing capacity of the drying processing unit 2. It shall adjust suitably in the range of -3MPa. In short, what is necessary is just to be able to sufficiently evaporate the evaporation component possessed by the workpiece 3 in the drying processing section 2.
However, the temperature of the superheated steam is lowered by being partly dissipated and absorbed by the outside air temperature while being transported through the drying heating gas supply pipe 11. In order to compensate for this temperature drop and to keep the temperature distribution in the drying unit 2 appropriate, a high-frequency current is applied to the induction heating means 5 to inductively heat the porous partition wall 1.
This prevents the temperature in the drying processing unit 2 from decreasing due to heat exchange with the superheated steam and evaporation of the evaporation components of the object to be processed 3, so that the inside of the drying processing unit 2 exceeds a predetermined temperature. Hold it to prevent the drying efficiency from decreasing.
[0022]
The to-be-processed object 3 that has been dried in the drying processing unit 2 is lifted by the superheated steam carrying air stream that is sucked from the exhaust processing unit 14 and directed to the discharge port 7c, and the porous partition wall 1 is discharged from the discharge port 7c through the opening 10 and the space above it, and is already separated and collected by the separation and collection unit 13 because it is already solid separated. The superheated steam and the vaporized components of the object 3 after the object 3 is separated and recovered by the separation and recovery unit 13 are cooled and liquefied and reduced in the exhaust processing part 14 and recovered. . In addition, when the said evaporation component is water, all can be collect | recovered as water and subsequent disposal processing is easy.
[0023]
Next, another embodiment of the present invention will be described.
<1> When the heating means 4 is the induction heating means 5, the porous partition wall 1 may be a magnetic metal other than ferritic stainless steel.
The heating unit 4 may be a heating unit other than the induction heating unit 5. For example, the porous partition wall 1 is formed of a conductive material having a predetermined electric resistance, and an appropriate voltage is applied between the upper end and the lower end of the porous partition wall 1 so that a current flows directly through the porous partition wall 1. Joule heat may be generated.
[0024]
<2> In the above-described embodiment, the opening 10 is provided at the upper end of the porous partition wall 1, and the exhaust air is discharged from the discharge port 7 c to the outside by being carried on the superheated water vapor, and separated and recovered outside. However, you may make it collect | recover the said to-be-processed objects 3 which were dried in the said drying container 7. FIG.
For example, as shown in FIG. 2, the drying processing unit 2 including the upper and lower openings thereof is surrounded by the porous partition wall 1 to form a closed space, and the workpiece 3 after drying processing is You may make it collect | recover in the drying process part 2. FIG. In this case, the entire porous partition wall 1 can be easily collected from the inside of the drying container 7 and can be easily installed, and the object 3 to be processed before the drying process is preliminarily placed in the drying processing unit 2. The porous partition wall 1 in the supplied state is installed in the drying container 7. Therefore, the spray mechanism 6 and the bottom member 9 shown in FIG. 1 are not provided.
The superheated steam pressure-supplied into the drying container 7 is jetted from the side wall portion and the bottom surface portion of the porous partition wall 1 into the drying processing portion 2 and used for drying processing in the drying processing portion 2. Then, the superheated steam after the superheat treatment and the vaporized component of the workpiece 3 pass through the upper surface portion of the porous partition wall 1 and are discharged to the outside from the discharge port 7c. The drying process in the drying process unit 2 is initially performed exclusively in the lower part of the drying process unit 2. However, as the drying process proceeds, the workpiece 3 becomes lighter and rides on the rising airflow of the superheated steam. Thus, the drying process is promoted by staying floating in the drying processing unit 2. Here, the fine powder in the object to be treated 3 after the drying treatment is captured by the upper surface portion in the porous partition wall 1 and is prevented from flowing out. Note that the spray mechanism 6 may be provided depending on the type of the workpiece 3.
In this embodiment, every time a predetermined drying processing amount is digested, the processed material 3 after the drying processing generated in the drying processing section 2 is collected together with the porous partition wall 1.
[0025]
<3> The shapes of the porous partition wall 1 and the drying container 7 are not necessarily cylindrical. Further, the axial direction of the axis may be other than the vertical direction. The positions of the air inlet 7b and the outlet 7c can be changed as appropriate.
[0026]
<4> In the above embodiment, the heating gas for drying is generated by heating outside the drying container 7. However, the drying gas may be configured to be heated in the drying container 7. The effect of the present invention can be exhibited in that the temperature distribution in the drying processing unit 2 can be appropriately controlled by the heating means 4.
[0027]
<5> The heating gas for drying may be a heated dry gas such as superheated steam other than superheated steam or high-temperature dry air.
[0028]
<6> In the porous partition wall 1, the average pore diameter and the porosity can be appropriately changed. Further, the material and the production method are not necessarily limited to the porous metal sintered body produced by hot isostatic pressing, and for example, a large number of micropores which are closed by electric discharge machining or ultrasonic machining. It may be made of a metal material having a plurality of pores, or may be formed by processing a sponge-like metal into a porous body. Furthermore, it may be a nonmetallic porous body as long as it can be heated by some means.
[0029]
<7> The object to be treated 3 is not particularly limited, but may be a slurry such as sludge or a solution such as salt water, and can be fluidized and supplied. It may be a fine powder.
[0030]
In addition, although the code | symbol is written in order to make contrast with drawing convenient for the term of a claim, this invention is not limited to the structure of an accompanying drawing by this entry.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view showing an embodiment of a drying apparatus according to the present invention. FIG. 2 is a cross-sectional explanatory view showing another embodiment of the drying apparatus according to the present invention. Cross-sectional explanatory drawing showing an example of the device 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 1 Porous partition 2 Drying process part 3 To-be-processed object 4 Heating means 5 Induction heating means 6 Spraying mechanism 6a To-be-processed object supply pipe 6b Nozzle 7 Drying container 7a Inner side wall 7b Air inlet 7c Outlet 8 Internal partition 9 Bottom member 10 Opening 11 Heating gas supply pipe for drying 12 Super heater 13 Separation and recovery unit 14 Exhaust processing unit

Claims (4)

A drying treatment part (2) is formed inside the porous partition wall (1), and a heating gas for drying is jetted from the outside to the inside of the porous partition wall (1) to be treated in the drying treatment part (2). A drying device for drying the product (3),
A spray mechanism (6) for spraying the workpiece (3) upward into the drying processing section (2) is installed at the lower part of the drying processing section (2), and the processing target after drying processing A drying apparatus comprising a heating means (4) for providing an opening (10) for discharging (3) at an upper end portion of the drying processing section (2 ) and heating the porous partition wall (1).   The drying according to claim 1, wherein the porous partition wall (1) is made of magnetic metal, and the heating means (4) is an induction heating means (5) for generating an induced current in the porous partition wall (1). apparatus.   The drying apparatus according to claim 1 or 2, wherein the heating gas for drying is superheated steam. The drying apparatus according to claim 1, 2 or 3, wherein the porous partition wall (1) is formed of a porous metal sintered body formed by hot isostatic pressing.

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