JP2004353975A - Drying installation and its operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drying installation for drying powder to be dried in contact with drying gas, preventing the melting and alteration of the powder to be dried. <P>SOLUTION: A bypass line which bypasses a heating means is provided in a main gas supply passage passing through the heating means for supplying the drying gas to an airborne dryer. On-off valves are provided on the midways of the main gas supply passage and the bypass line, respectively. The on-off valves are controlled corresponding to the temperature of exhaust gas from the airborne dryer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a fluidized dryer, a flash dryer, a rotary dryer, and the like, while dispersing the powder to be dried by hot air gas or hot air gas, and evaporating moisture attached to the powder to be dried by the amount of heat such as hot air. The present invention relates to a drying facility provided with an air-flow dryer for drying and a method of operating the same.
[0002]
[Prior art]
BACKGROUND ART Drying equipment equipped with a flash dryer is widely used in fields such as the chemical industry and the food industry, and is used for drying powders such as synthetic resins, inorganic salts, corn starch, and fibers.
[0003]
In this type of drying equipment, the powder to be dried is put into a flow of a relatively high-temperature drying gas, and the powder to be dried is dispersed and supplied into a flash dryer to evaporate moisture in a short time. It is common to adopt a configuration.
[Patent Document]
Tokuhei 8-27132
[0004]
[Problems to be solved by the invention]
Therefore, in this type of drying equipment, the powder to be dried is not supplied to the drying gas due to clogging of the supply path of the powder to be dried, a failure of the supply device, or the supply amount is excessively small. If such a situation occurs, there is a problem that the drying gas having an excessive amount of heat in the air-flow dryer tends to cause melting or alteration of the powder to be dried. When the material to be dried is melted as described above, the melt adheres to the supply path, the inside of the flash drying apparatus, and the inside of the discharge path, so that the supply path and the like are further blocked.
[0005]
Therefore, a main problem of the present invention is that, in a flash drying apparatus, melting and alteration of the powder to be dried caused by an excessively high temperature of the drying gas supplied into the flash drying machine, and furthermore, An object of the present invention is to reliably prevent clogging in a supply path due to melting or the like.
[0006]
[Means for Solving the Problems]
The present invention which has solved the above-mentioned problems and the operation and effect thereof are as follows.
<Invention according to claim 1>
An air-flow dryer for drying the powder to be dried by contacting the powder to be dried with a gas for drying; a main gas supply path for sending a drying gas to the air-flow dryer; Heating means for heating a drying gas provided in the middle of the path, a powder supply path to be dried connected to the main gas supply path at a stage subsequent to the heating means, and a drying powder from the air-flow dryer. Drying equipment comprising a discharge path for discharging the body together with the drying gas,
The former is connected to the main gas supply passage before the heating unit and the latter after the heating unit and before the connection part of the powder supply passage to be dried, and is used for drying without passing through the heating unit. A bypass passage capable of supplying gas to the flash dryer is provided, and an on-off valve is provided on the bypass passage and at a stage preceding the heating means in the main gas supply passage,
Drying equipment characterized in that the flow rate and temperature of the drying gas flowing into the air-flow type drying apparatus can be adjusted by adjusting the opening / closing degree of each on-off valve.
[0007]
<Invention according to claim 2>
The drying equipment according to claim 1, wherein the air-flow dryer is a swirl-flow dryer.
[0008]
<Invention of Claim 3>
Temperature measurement means for measuring the temperature of the exhaust gas in the exhaust path, and on-off valve operating means for automatically operating the degree of opening and closing of each on-off valve based on the temperature of the exhaust gas measured by the temperature measurement means, The drying facility according to claim 1, further comprising:
[0009]
<Invention of Claim 4>
A dry powder supply amount measuring means for measuring an amount of the dry powder passing through the dry powder supply passage per unit time; and an automatic opening / closing degree of each open / close valve according to the supply amount of the dry powder. The drying equipment according to any one of claims 1 to 3, further comprising opening / closing valve operating means for operating each of the drying means.
[0010]
<Invention according to claim 5>
An air-flow dryer for drying the powder to be dried by contacting the powder to be dried with a gas for drying; a main gas supply path for sending a drying gas to the air-flow dryer; Heating means for heating a drying gas provided in the middle of the path; a powder supply path to be dried connected to the main gas supply path at a stage subsequent to the heating means; And a discharge path for discharging together with the drying gas,
The former is connected to the main gas supply passage at a stage before the heating unit and the latter stage of the heating unit and before the connection portion of the powder supply passage to be dried, and is used for drying by bypassing the heating unit. In a method of operating a gas-flow type drying apparatus, a bypass path capable of supplying gas to a gas-flow type dryer is provided, and an on-off valve is provided on the bypass path and at a stage preceding the heating means in the main gas supply path. So,
A method for operating a drying facility, comprising: adjusting a degree of opening and closing of each on-off valve to adjust a flow rate and a temperature of a drying gas flowing into the air-flow type drying apparatus.
[0011]
<Invention of claim 6>
The method according to claim 5, wherein the temperature of the exhaust gas in the exhaust path is measured, and the degree of opening and closing of each of the on-off valves is operated based on the measured temperature.
[0012]
<Invention of claim 7>
7. The amount of powder to be dried that passes through a supply passage for powder to be dried per unit time, and the degree of opening and closing of each of the on-off valves is adjusted according to the supply amount of the powder to be dried. Operating method of drying equipment.
[0013]
(Effect)
According to the present invention, the heating device is connected to the main gas supply passage at a stage before the heating device and at a stage after the heating device and before the connection portion of the powder supply path to be dried, and By providing a bypass that can bypass and supply the drying gas to the flash dryer, the drying gas can be sent to the connection of the powder supply path to be dried without heating without passing through the heating means. Becomes possible. And, since the on-off valve is provided in the bypass path and in the preceding stage of the heating means in the main gas supply path, by adjusting the degree of opening and closing of each on-off valve, the heating means is provided in the preceding stage of the connection with the drying supply path. The gas for heating drying and the gas for non-heating drying which are not heated are mixed, and the drying gas can be supplied to the airflow dryer through the connection portion and the connection portion. Transport and drying of the powder to be dried can be performed. Further, by providing the bypass path, only one supply source of the drying gas is required, and the equipment can be constructed at a lower cost than when the supply sources of the heating gas and the non-heating gas are separately provided. Here, if the air-flow dryer is a swirl-flow dryer, the size of the equipment can be reduced, and the equipment can be constructed at lower cost.
[0014]
When the drying equipment is constructed as described above, the temperature of the exhaust gas in the exhaust path is measured, and the degree of opening / closing of each on-off valve can be adjusted based on this temperature. In the air-flow dryer, the calorific value of the drying gas is used to evaporate the moisture attached to the powder to be dried, so that the temperature of the exhaust gas is usually lower than the temperature of the supplied drying gas. Therefore, if the temperature of the exhaust gas has not decreased, it can be understood that the supply of the powder to be dried is not properly performed. Therefore, by adjusting the degree of opening and closing of each of the on-off valves according to the temperature of the exhaust gas, it is possible to supply a drying gas at a temperature suitable for the wet substance, and to supply a dry powder by supplying an excessively high drying gas. Melting and alteration can be prevented.
[0015]
Such adjustment of the on-off valve is performed by automatically measuring the degree of opening and closing of each on-off valve based on the temperature of the exhaust gas measured by the temperature measuring means for measuring the exhaust gas temperature in the exhaust passage. By providing on-off valve control means for operating each of them, the on-off valve can be easily operated without the need for the facility manager or the like to operate, thereby reducing the burden on the facility manager and reducing human error.
[0016]
On the other hand, it is also possible to measure the amount of the powder to be dried passing through the supply passage for the powder to be dried and adjust the respective on-off valves accordingly to optimize the temperature of the gas for drying. In this case, the dry powder supply amount measuring means for measuring the supply amount of the dry powder in the dry powder supply path, and each opening and closing in accordance with the supply amount of the dry powder. If the on-off valve control means for automatically operating the degree of opening and closing of the valve is provided, the on-off valve is controlled in the same manner as the on-off valve control means for automatically adjusting the degree of adjustment of the on-off valve based on the exhaust gas. This can be easily performed without the necessity of operation by a facility manager or the like, thereby reducing the burden on the facility manager, reducing human errors, and the like.
[0017]
In addition, it is also possible to measure both the exhaust gas temperature and the supply amount of the powder to be dried, and to adjust the on-off valve based on these measurement locations. Measuring both the exhaust gas temperature and the supply rate of the powder to be dried provides a more detailed picture of the drying gas and the wet substance passing through the supply passage or the flash dryer, and these measured values are obtained. By adjusting each on-off valve based on the above, melting of the dried material and prevention of deterioration of the dried product can be more reliably prevented.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a flowchart showing an outline of the drying equipment according to the present embodiment.
Reference numeral 10 in FIG. 1 denotes a drying gas generator. Regarding the drying gas G to be generated, dry air, a dry inert gas, or the like may be appropriately selected depending on the type of the powder to be dried WP. When dry air is used, the drying gas generator 10 can be a blower such as a blower.
[0019]
The drying gas G generated by the drying gas generator 10 passes through a main gas supply path (a path passing through L1, L11, and L12 in the figure) and a bypass path L2 after removing dust and the like mixed by a filter 15. To the flash dryer 50. A non-contact heat exchanger 20 is installed in the middle of the main gas supply passage L11 to heat the drying gas G. The heat exchanger 20 exchanges heat with the high-temperature steam S to dry the gas G. G is heated to a predetermined temperature (usually about 70 to 180 ° C.). The heating means is not particularly limited to a means for heating by heat exchange with high-temperature steam, and a conventionally known heating means for heating a flowing gas can be used. The heating and drying gas _GH heated to a predetermined temperature by heat exchange is further sent to the flash dryer through the main gas supply paths L11 and L12.
[0020]
A chute L3 (wet substance supply path) for supplying the powder to be dried WP is connected to the main gas supply path L12 on the way from the heat exchanger 20 to the flash dryer 50. The powder to be dried WP is supplied from the chute L3 to the drying gas Gi flowing through the main gas supply path L12. The vicinity of the inlet is covered with a heat insulation jacket, so that the temperature of the powder does not rise rapidly. Note that, as the heat insulation jacket, a jacket having a conventionally known configuration that allows a fluid at a predetermined temperature to flow and keeps the temperature in the passage constant can be used.
[0021]
On the other hand, a supply hopper 40 that supplies a predetermined amount of the powder to be dried WP is provided upstream of the chute L3. The powder to be dried WP is heated to a predetermined temperature (usually about 30 to 50 ° C.) before being introduced into the main gas supply passage L12. In the middle of the chute L3, a supply amount measuring means 45 for measuring the supply amount of the powder to be dried WP is provided, and the amount of the powder to be dried WP passing through the inside of the chute L3 per unit time is measured. Is done.
[0022]
The powder to be dried WP supplied to the main gas supply passage L12 is sent into the air-flow dryer 50 while being diffused by the drying gas Gi flowing in the main gas supply passage L12. In the air-flow dryer 50, the moisture on the surface of the powder to be dried is evaporated by the diffusion of the powder to be dried WP by the air current and the heat exchange by ensuring the contact time between the powder to be dried WP and the gas for drying Gi. The powder to be dried is dried in a short time. Here, as the flash dryer 50, a conventionally known flash dryer for drying the wet substance by contact between the wet substance and the drying gas can be used without any problem. Specific examples include a fluid dryer, a flash dryer, a rotary hot air dryer (warm air dryer), a circulating dryer, and the like. Above all, as disclosed in Japanese Patent Publication No. 8-27132, a swirling flow in which a wetting substance is supplied in a cylinder in a tangential direction on a drying gas to generate a swirling flow to dry the wetting substance. The dryer is desirable because the equipment can be downsized.
[0023]
The dry powder, which is dried in a stream dryer within 50 (dry matter) P is discharged to the discharge passage L4 with dry gas (exhaust gas) G _E. The discharge passage L4 is connected to a separation device 60 for separating the gas and the powder such as a cyclone, a dry matter P is separated from the exhaust gas G _E in the separation device.
[0024]
By the way, the drying equipment of the present embodiment is characteristically branched at a stage preceding the heat exchanger 20 in the main gas supply path, bypassing the heat exchanger 20, and entering the inlet Z of the powder to be dried WP. Is provided again with a bypass passage L2 that joins the main gas supply passage. Therefore, the drying gas is heated in the path passing through the heat exchanger 20, and the drying gas is not heated in the bypass path. In the main gas supply path, a first opening / closing valve 30A is provided between a junction X with the bypass and a junction Y (hereinafter, also referred to as a heating path L11). The flow rate of the drying gas _GH passing through the heat exchanger 20 is adjusted by adjusting the opening / closing degree of. A second opening / closing valve 30B is also provided in the middle of the bypass passage L2. By adjusting the opening / closing degree of the second opening / closing valve 30B, the drying operation toward the flash dryer 50 through the bypass passage L2 is performed. The flow rate of the service gas _GL is adjusted. Therefore, when the first on-off valve 30A is closed and the second on-off valve 30B is opened, the unheated low-temperature drying gas _GL flows after the junction Y, and the first on-off valve 30A is opened. When the second on-off valve 30B is closed, the heated high-temperature drying gas _GH flows through the inlet Z. When the first on-off valve 30A and the second on-off valve 30B are both opened, the gas for drying passing through the heating path L11 and the gas for drying passing through the bypass path L2 join at the junction Y, and the air-flow dryer Go to 50. When the two on-off valves 30A, 30B are opened as described above, the gas temperature and the gas flow rate of the drying gas Gi flowing after the junction Y can be adjusted by appropriately operating the degree of opening and closing of the on-off valves 30A, 30B.
[0025]
As the first on-off valve 30A and the second on-off valve 30B, a conventionally known means for adjusting the flow rate of gas flowing in the pipeline, such as a valve, can be used without any problem.
[0026]
Closing degree of the first on-off valve 30A and the second on-off valve 30B is a temperature measuring means 56 for measuring the temperature of the exhaust gas G _E comprises a dry matter P in the middle of the discharge passage L4 provided, measured here The operation is performed according to the temperature of the exhaust gas (usually about 35 to 80 ° C.). When the temperature and flow rate and the dry powder of the dried gas G _i supplied to the air flow type dryer is constant, the temperature of the exhaust gas G _E will remain substantially constant, but the dry powder WP put some cause, for example when stopped or reduced due to a failure of the supply device, the temperature rise of the exhaust gas G _E since heat of the drying gas G _i used for evaporation of the dried powder WP is not lost I do. Therefore, by operating the opening and closing degree of the valves 30A, 30B when a change in the temperature of the exhaust gas G _E measured by the temperature measuring means 56 has occurred, the gas flow rate supplied to the airflow dryer 50 The temperature is adjusted to a desired value, so that an excessively high temperature or an excessive inflow of the drying gas is prevented from being supplied into the flash dryer 50. Here, the temperature measuring means 56 is desirably provided at a position close to the flash dryer 50 in order to shorten the time lag from when the temperature is measured to when the on-off valves 30A and 30B are operated.
[0027]
Adjustment of the first on-off valve 30A and the second on-off valve 30B, for example, when the temperature of the exhaust gas G _E measured by the temperature measuring means 56 is equal to or higher than a predetermined temperature, closing the first on-off valve 30A heating The supply of the drying gas _GH may be stopped, and the second on-off valve 30B may be opened to allow only the low-temperature drying gas _GL to flow, or the first on-off valve 30A and the second on-off valve 30B may be operated. Then, the supply amount of the non-heating and drying gas _GL may be increased and the supply amount of the heating and drying gas _GH may be reduced to adjust the gas flow rate and the gas temperature after the mixing section Y. Also, rather than adjusting the time it has reached a predetermined temperature, the opening and closing degree of the first on-off valve 30A and the second on-off valve 30B to adjust from time to time continuously by operating according to variations in the temperature of the exhaust gas G _E You may do so.
[0028]
The first on-off valve 30A and the second on-off valve 30B can also be adjusted according to the measured value of the supply amount of the wet and dry product WP passing through the chute L3. In this case, the first on-off valve 30A and the second on-off valve 30B are adjusted, for example, by closing the first on-off valve 30A when the supply amount measured by the supply amount measuring device 45 becomes equal to or less than a predetermined amount. The supply of the heating and drying gas _GH may be stopped to open the second on-off valve so that only the low-temperature drying gas flows, or by adjusting the first and second on-off valves and the second on-off valve, The gas flow rate and the gas temperature after the mixing section Y may be increased by increasing the non-heating drying gas amount and decreasing the heating drying gas amount. When adjusting the gas temperature and the flow rate, the degree of opening and closing of the first opening / closing valve 30A and the second opening / closing valve 30B is continuously adjusted as needed in accordance with a change in the supply amount, instead of adjusting when the predetermined temperature is reached. You may make it operate and adjust.
[0029]
Temperature and the dry powder off valves 30A according to the measured values of both the supply amount of the WP of the exhaust gas G _E, may adjust the opening degree of 30B. The operation of each of the on-off valves 30A and 30B may be manually performed by a facility manager or the like at a site or a control room, or, for example, the on-off valves are automatically opened and closed to a predetermined degree according to a known temperature. A known computer control system or the like that operates as described above may be used.
[0030]
The operation of the opening / closing degree of each of the on-off valves 30A and 30B as described above causes a situation in which the object to be dried WP is not inserted due to a failure of the object to be dried supply device or the like. In the discharge path L4, the object to be dried is prevented from contacting with an excessively high temperature gas to be melted and deteriorated. Further, the dry matter supply device can be repaired without stopping the operation of the drying gas generator 10 or the separation device 60 such as a cyclone. In addition, in the conventional equipment, if such a situation that the object to be dried WP is not introduced occurs, the drying gas generator 10 needs to be stopped, so that the dry powder is placed in the discharge path L4 or the air-flow dryer 50. Alternatively, there was a problem that the powder to be dried stayed in the passage and it was necessary to remove such remaining undried matter. However, this equipment discharges all the dried and dried matter in the passage from the passage. After that, the maintenance can be performed by stopping the equipment, so that the maintenance performance can be remarkably improved.
[0031]
【The invention's effect】
As described above in detail, according to the present invention, even when the supply of the powder to be dried is not performed, the drying gas at an excessively high temperature is not supplied to the drying device, and the melting of the powder to be dried or Clogging in the supply path due to the above is prevented.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a drying facility according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Dry gas supply apparatus (blower), 15 ... Filter, 20 ... Heating means (non-contact type heat exchanger), 30A ... 1st opening / closing valve, 30B ... 2nd opening / closing valve, 40 ... Heating box, 45 ... Supply amount Measuring means, 50: sieve device, 56: exhaust gas temperature measuring means, 60: separating device, 80, WP: powder to be dried, P: dry powder, G: gas for drying, _GH : gas for heating and drying , G L _... unheated drying gas, G E _... exhaust gas, L1 ... main gas supply passage, L2 ... bypass, L3 ... the dry powder supply channel (chute), L4 ... discharge passage.

Claims (7)

An air-flow dryer for drying the powder to be dried by contacting the powder to be dried with a gas for drying; a main gas supply path for sending a drying gas to the air-flow dryer; Heating means for heating a drying gas provided in the middle of the path; a powder supply path to be dried connected to the main gas supply path at a stage subsequent to the heating means; Drying equipment comprising a discharge path for discharging the body together with the drying gas,
The former is connected to the main gas supply passage before the heating unit and the latter after the heating unit and before the connection part of the powder supply passage to be dried, and is used for drying without passing through the heating unit. A bypass passage capable of supplying gas to the flash dryer is provided, and an on-off valve is provided on the bypass passage and at a stage preceding the heating means in the main gas supply passage,
Drying equipment characterized in that the flow rate and temperature of the drying gas flowing into the air-flow type drying apparatus can be adjusted by adjusting the opening / closing degree of each on-off valve. The drying equipment according to claim 1, wherein the air-flow dryer is a swirl-flow dryer. Temperature measurement means for measuring the temperature of the exhaust gas in the exhaust path, and on-off valve operating means for automatically operating the degree of opening and closing of each on-off valve based on the temperature of the exhaust gas measured by the temperature measurement means, The drying facility according to claim 1, further comprising: A dry powder supply amount measuring means for measuring an amount of the dry powder passing through the dry powder supply passage per unit time; and an automatic opening / closing degree of each open / close valve according to the supply amount of the dry powder. The drying equipment according to any one of claims 1 to 3, further comprising opening / closing valve operating means for operating each of the drying means. An air-flow dryer for drying the powder to be dried by contacting the powder to be dried with a gas for drying; a main gas supply path for sending a drying gas to the air-flow dryer; Heating means for heating a drying gas provided in the middle of the path; a powder supply path to be dried connected to the main gas supply path at a stage subsequent to the heating means; And a discharge path for discharging together with the drying gas,
The former is connected to the main gas supply passage at a stage before the heating unit and the latter stage of the heating unit and before the connection portion of the powder supply passage to be dried, and is used for drying by bypassing the heating unit. In a method of operating a gas-flow drying facility, a bypass which can supply gas to a gas-flow dryer is provided, and an on-off valve is provided at the bypass and at a stage preceding the heating means in the main gas supply path. So,
A method for operating a drying facility, comprising: adjusting a degree of opening and closing of each on-off valve to adjust a flow rate and a temperature of a drying gas flowing into the air-flow type drying apparatus. The method according to claim 5, wherein the temperature of the exhaust gas in the discharge path is measured, and the degree of opening / closing of each of the on-off valves is operated based on the measured temperature. 7. The amount of powder to be dried that passes through a supply passage for powder to be dried per unit time, and the degree of opening and closing of each of the on-off valves is adjusted according to the supply amount of the powder to be dried. Operating method of drying equipment.

Images