JP3227076B2 - Method of treating liquid containing solidified substance by dipping drum dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a liquid containing a substance to be solidified by a dip-type drum dryer, which solidifies and collects salts and organic substances contained in the liquid to be treated such as waste water. About.

[0002]

2. Description of the Related Art Wastewater from factories and research facilities contains various salts and organic substances in a dissolved or dispersed state. If wastewater containing such salts and organic substances is discharged directly into rivers and the like, there is a risk of causing environmental pollution problems. Therefore, in general, desalination treatment and organic matter decomposition treatment are performed, and the After adjusting to the water quality inside,
It is released to rivers.

[0003] In this case, when the concentration of impurities (salts, organic substances) in the waste water is high, the solvent (or dispersion medium) is removed by heat treatment, and the solute (or dispersion) is solidified and separated and removed. Is being done. Although this method is particularly useful in a completely closed system in which drainage is not allowed, generally, it can be disposed of in a solid form, so that it is small in volume, easy to handle, and easy to dispose. It can be said that this is an advantageous method.

As a method of performing a solidification treatment, a liquid to be treated such as drainage is brought into contact with a rotating drum provided with a heating means,
There is known a treatment method using a dip-type drum dryer, in which a treatment liquid attached to a drum surface is dried to solidify salts and organic substances (hereinafter, referred to as solidification treatment substances) in the treatment liquid. In the processing by the dip-type drum dryer device, a method of performing processing while continuously supplying a liquid to be processed to a storage tank called a pan at a constant speed has conventionally been adopted.

[0005]

However, the amount of the solidified processing substance in the liquid to be processed supplied into the pan within a certain period of time does not always coincide with the amount of the solid matter dried and solidified by the drum dryer. Without this, an unbalanced state usually occurs in which the latter is less. This is considered to be caused by the phenomenon of spontaneous evaporation of the liquid to be treated in the bread from the liquid surface and a part of the scraped solids falling into the bread. For this reason, the amount of the solidification target substance in the liquid to be processed in the bread gradually increases as the processing time elapses. As the concentration of the substance to be solidified in the liquid to be treated in the pan progresses, the liquid to be treated does not uniformly adhere to the drum, or in extreme cases, it becomes difficult to stir the liquid to be treated in the pan. Sometimes. For this reason, conventionally, the complicated operation of stopping the operation when the liquid concentration in the bread has increased, removing the bread from the device casing, discharging the liquid to be treated in the bread and cleaning the inside of the bread is required. there were. When the concentration in the liquid to be treated in the bread proceeds relatively slowly,
The frequency of cleaning the inside of the bread can be reduced, and the processing operation is not greatly hindered, but the concentration rate of the liquid to be treated in the bread is remarkably high, for example, when the suspended liquid is contained in the liquid to be treated. When the speed is fast, there is a problem that the inside of the bread must be frequently cleaned.

[0006] Even when the concentration of the solidified substance in the liquid to be treated in the bread is not so advanced, the solidified substance to be solidified in the liquid to be treated is dried and solidified on the drum surface with the concentration of the substance to be solidified. If the solids are sticky or become too hard and the scraping properties when peeling off the solids from the drum are poor, or even if a slight concentration occurs, the viscosity and drying of the liquid to be treated It is necessary to frequently clean the inside of the bread, for example, in cases where the viscosity or the like of the product changes remarkably and hinders the processing operation. For example, when a high-boiling alcohol is contained in the liquid to be treated, the high-boiling alcohol in the liquid to be treated in the bread is inferior in adhesion to the drum surface as compared with the salts, and thus has a high degree of concentration. As the concentration of the high-boiling alcohol in the liquid to be treated in the bread increases, the high-boiling alcohol content in the solid dried and solidified on the drum surface also increases. Since the solid does not dry and solidify, there is a problem that the viscosity of the solid is increased and the scraping property of the solid is deteriorated.

[0007] The present invention has been made in view of the above points,
Solidification processing by a dip-type drum dryer that can perform continuous processing for a long time without the need for complicated operations such as temporarily stopping the operation of the dip-type drum dryer and frequently cleaning the inside of the pan. It is an object of the present invention to provide a method for treating a substance-containing liquid.

[0008]

According to the present invention, (1) a liquid to be treated containing a substance to be solidified is supplied into a pan of a dipping drum dryer, and the liquid to be treated is rotated in the pan. A liquid containing a substance to be solidified by a dip-type drum dryer in which the liquid to be treated is adhered to the surface of the drum by being brought into contact with a drum, and the substance to be solidified is dried by heating means to solidify the substance to be solidified. In the processing method of
In the bread, the step of supplying the liquid to be treated containing the substance to be solidified, and the step of stopping the supply of the liquid to be treated and supplying the diluent into the pan are alternately and repeatedly performed. A method of treating a liquid containing a substance to be solidified by a dipping drum dryer, (2) supplying a liquid to be treated containing a substance to be solidified into a pan of the dipping drum dryer, and treating the liquid to be treated; The liquid to be treated is adhered to the surface of the drum by being brought into contact with the drum rotating in the pan, and the liquid to be treated is dried by heating means to solidify the substance to be solidified. In the method for treating a chemical conversion substance-containing liquid, in the bread,
(3) a method of treating a liquid containing a substance to be solidified by a dip-type drum dryer, wherein the liquid to be treated containing the substance to be solidified is supplied, and the diluent is intermittently supplied into the pan. ) In the liquid to be treated and the diluent,
(1) The method of treating a liquid containing a substance to be solidified by a dipping drum dryer according to the above (1) or (2), wherein the liquid to be treated is a substance having a high boiling point. The gist of the present invention is a method for treating a liquid containing a substance to be solidified by a dipping drum dryer according to any one of the above (1) to (3), characterized in that the liquid is contained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of a flow of a dip type drum dryer device according to an embodiment of the present invention,
FIG. 2 is an explanatory diagram showing another example of the flow of the dip type drum dryer device according to the embodiment of the present invention. 1 and 2, reference numeral 1 denotes a dip-type drum dryer, and a drum 2 having a heating means is rotatably provided in a casing 2 of the drum dryer 1. As a heating means for the drum 3, a heating medium supply means such as steam is provided inside the drum 3. A pan 4 is provided below the casing 2, and the processing liquid 5 is supplied into the pan 4, and the lower part of the drum 3 is immersed in the processing liquid 5. Further, a stirring means 6 such as an agitator for stirring the liquid 5 to be treated in the pan 4 is provided in the pan 4. A scraper 7 for scraping solids from the surface of the drum 3 is provided in the casing 2.
, And an outlet 9 for taking out the scraped solid matter is provided below. Further, a gas outlet 8 for discharging vaporized vapor is provided at an upper portion of the casing 2.

A supply mechanism for the liquid to be treated and the diluting liquid is connected to the drum dryer 1. The supply mechanism includes a to-be-processed liquid storage tank 11 for storing the to-be-processed liquid sent from the to-be-processed liquid supply line 10, and a diluent storage tank 13 for storing the diluent sent from the diluent liquid supply line 12. A supply line 21 for supplying the liquid to be treated or the diluting liquid from the storage tanks 11 and 13 into the pan 4 of the drum dryer 1 is provided.

16 (FIG. 1) and 16A, 16B (FIG. 2)
Is a liquid feed pump for supplying the liquid to be treated and the diluting liquid to the pan 4. In the apparatus having the flow shown in FIG. 1, both the liquid to be treated and the diluting liquid are supplied by a common liquid supplying pump 16. In the apparatus having the flow shown in FIG. 2, the liquid supply pump 16A for the liquid to be treated and the liquid supply pump 16B for the diluting liquid are separately provided. 1
Reference numerals 4 and 15 denote on-off valves provided on the outlet side of the liquid-to-be-treated storage tank 11 and the diluent storage tank 13, respectively, and reference numerals 22 and 23 denote stirring means provided in the respective storage tanks 11 and 13.

The present invention is implemented by using the apparatus configured as described above. The present invention, for the purpose of improving the scraping properties and the like of solids, a liquid to be treated with a solidification modifier as necessary,
It can be mixed with a diluent, but when adding and mixing this solidification regulator, each storage tank 1
An apparatus having a mechanism for supplying a solidification adjusting agent to 1, 13 is used.

As shown in FIGS. 1 and 2, such a supply mechanism includes a hopper 17 for storing a solidifying modifier, and a liquid storage tank 11 and a diluent storage tank 1 from the hopper 17.
A feeder 18 for supplying a solidification modifier to 3;
Supply lines 24 and 25 connecting the feeder 18 and the storage tanks 11 and 13, and an on-off valve 1 provided on each supply line
9 and 20.

Examples of the liquid to be treated include those in which a substance to be solidified (a substance to be solidified) such as salts and organic substances is dissolved and / or dispersed in water or an aqueous medium mainly composed of water. The medium in which the substance to be solidified is dissolved and dispersed is not necessarily limited to water. In addition, the material to be solidified is
It is not limited to being disposed of, but may be used as a product. Therefore, the method of the present invention, in addition to treating wastewater discharged mainly from factories or research facilities as a liquid to be treated, such as plating wastewater, laboratory wastewater, ion-exchange resin regeneration wastewater, and the like, solidification of food, The present invention can also be applied to the case where a product is solidified and recovered from a liquid to be treated such as an aqueous solution containing the product, such as in the case of powdering. The solidified product obtained in the present invention may partially include a viscous substance that is not dried and solidified. As such a viscous substance, for example, there is a high-boiling substance (for example, a high-boiling alcohol such as glycerin), and even if such a high-boiling substance is contained, the method of the present invention can be carried out. It is preferable to add and mix a solidification modifier as described below.

In the case where the liquid to be treated is waste water, if the concentration of impurities such as salts in the waste water is relatively low, it is economical to directly apply such low-concentration waste water to the method of the present invention. Not a good idea. Such relatively low-concentration wastewater is usually desalted by a reverse osmosis membrane method, an electric deionization method, etc., but the concentrated water generated by the desalination treatment has a high salt concentration. It is practically preferable to apply such concentrated water to the method of the present invention to carry out the treatment.

On the other hand, the diluting liquid may be any liquid that can dilute the liquid to be treated, and usually a liquid of the same kind as the solvent or dispersion medium in the liquid to be treated is used. For example, when the liquid to be treated is water or an aqueous medium mainly composed of water in which the substance to be solidified is dissolved or dispersed, it is usually preferable to use water or an aqueous medium as the diluting liquid.

In one example of the method of the present invention, the processing is performed while alternately supplying the liquid to be treated and the diluting liquid to the pan 4 at regular intervals using the apparatus having the flow shown in FIG. The liquid to be treated and the diluting liquid are alternately opened and closed at predetermined time intervals by the on-off valve 14 of the to-be-treated liquid storage tank 11 and the on-off valve 15 of the diluting liquid storage tank 13, so that the liquid is transferred to the pan 4 alternately. Supplied. The supply speed of the liquid to be treated and the diluting liquid
The rotation speed, the heating temperature and the type of the liquid to be treated, the composition, etc., and cannot be uniquely determined, but usually,
The feed rate of the liquid to be treated 20~40kg / m about ² · hr, the feed rate of the diluent is preferably at 20~40kg / m about ² · h.

The time during which the liquid to be treated can be continuously supplied to the pan 4 depends on the type and concentration of the substance to be solidified in the liquid to be treated and the concentration of the substance to be solidified in the liquid to be treated in the pan 4. It can be appropriately determined in consideration of various conditions such as the magnitude of the speed to be performed. For this reason, for the time during which the liquid to be treated can be continuously supplied to the pan 4, the liquid to be treated is preliminarily treated, the stirring property of the liquid 5 to be treated in the pan, and the drum of the dried and solidified solid material. It is preferable to determine in consideration of the scraping property from the surface. On the other hand, when the supply of the liquid to be treated is stopped and the diluent is supplied to the pan 4, the concentration of the substance to be solidified in the liquid 5 to be treated in the pan is changed by the concentration of the substance to be solidified in the original liquid to be treated. The determination is made with reference to supplying the diluent until the solution is diluted to the same level as the concentration. The time during which the concentration of the substance to be solidified in the liquid to be treated 5 in the bread can be reduced to a predetermined value by the supply of the diluting liquid depends on the concentration of the liquid to be treated in the pan 4 and the supply amount of the diluting liquid per unit time. Here, the concentration of the liquid to be treated in the bread is determined based on the continuous supply time of the liquid to be treated into the bread 4 and the solidified material in the liquid to be treated 5 in the bread 4 It depends on the speed at which the liquid 5 is processed. For this reason, it is preferable that the continuous supply time of the diluting liquid is also determined in advance based on the data of the preliminary processing.

Conditions such as time and speed for alternately supplying the liquid to be treated and the diluting liquid can be determined using the water content of the liquid to be treated 5 in the bread as a scale. In the case of the liquid to be treated containing a suspended substance, the water content of the liquid to be treated 5 in the bread is maintained at about 30 to 50% by weight, and in the case of the liquid to be treated containing no suspended substance. It is preferable to supply the liquid to be treated and the diluting liquid to maintain the water content of the liquid to be treated 5 in the pan at about 40 to 60% by weight. However, the water content in the liquid to be treated in the bread is only a guide, and it is preferable to determine the supply speed, supply time, and the like of the liquid to be treated and the diluting liquid by performing the preliminary treatment as described above.

The drum surface temperature (surface temperature) of the drum 3 in the drum dryer 1 is determined in consideration of the boiling point of the liquid component (solvent or dispersion medium) in the liquid to be treated, the melting point of the solidified substance to be dried and solidified, and the like. To be determined, but generally 120 to 14
It is about 0 ° C. The rotation speed of the drum 3
It is adjusted so that the object to be processed attached to the surface is dried and solidified while reaching the position of the scraper 7. Usually, it is preferable that the rotation speed of the drum 3 be about 2 to 10 rpm.

In order to prevent the solids dried and solidified on the surface of the drum 3 from sticking or becoming too hard, the scraping property of the solids is deteriorated. Conditioning agents can be added. As the solidification modifier, it is preferable to use a solid substance having no solubility or low solubility in the liquid to be treated or the diluting liquid and having a low solubility. Examples of such a solidification modifier include diatomaceous earth, bentonite, and the like.

If the liquid to be treated contains a high-boiling substance having a boiling point higher than the surface temperature of the drum 3 such as glycerin or tetramethylammonium hydroxide (TMAH),
The high-boiling substance is taken into a solid that has been dried and solidified on the surface of the drum 3 without being gasified. When the content of these high-boiling substances in the liquid to be treated is high or when the concentration in the bread 4 proceeds, the amount of the high-boiling substances contained in the dried and solidified solid increases, and the solid It becomes sticky and difficult to scrape. When the high-boiling substance is contained in the liquid to be treated, when the solidification modifier is added to the liquid to be treated and the diluting liquid, the high-boiling substance is easily attached to the drum together with the solidification modifier, and in particular, In the case of a liquid to be treated containing a high boiling substance, the addition of a solidification regulator is effective.

The amount of the solidifying modifier such as diatomaceous earth is
It is appropriately adjusted according to the type and amount of the high-boiling substance contained in the liquid to be treated. Usually, it is preferable to add the solidification modifier so that the content in the liquid to be treated and the diluent is about 1 to 15% by weight.

Next, the operation for treating the liquid to be treated using the apparatus having the flow shown in FIG. 1 will be described. On-off valve 15
Is closed, the open / close valve 14 is opened, and the liquid to be treated is supplied from the liquid to be treated storage tank 11 into the pan 4 of the drum dryer 1 by the liquid supply pump 16. When using the liquid to be treated mixed with the solidification modifier, the on-off valve 19 is opened, a predetermined amount of the solidification modifier is supplied from the hopper 17 into the storage tank 11 through the feeder 18, and the mixture is stirred by the stirring means 22. The liquid to be treated, which is uniformly mixed with the liquid to be treated and added and mixed with the solidifying agent, is supplied into the pan 4.

The liquid to be treated supplied to the pan 4 from the liquid to be treated storage tank 11 comes into contact with the drum 3, and the liquid to be treated attached to the surface of the drum 3 is heated by the drum 3 and reaches the position of the scraper 7. While drying. The liquid component in the liquid to be treated evaporates and is discharged from the gas discharge port 8, while the solid matter dried and solidified on the surface of the drum 3 is scraped off by the scraper 7 and discharged from the discharge port 9.

After the liquid to be treated is supplied to the pan 4 for a certain period of time, the on-off valve 14 is closed, the on-off valve 15 is opened, and the supply of the liquid to be treated is stopped. 4 When using the diluent mixed with the solidification modifier, the on-off valve 20 is opened in the same manner as described above, the solidification modifier is supplied from the hopper 17 into the storage tank 13, and the solidification modifier is The diluted liquid obtained by adding and mixing is supplied into the pan 4. The supply of the diluting liquid into the pan 4 reduces the concentration of the liquid to be treated in the pan, and the concentration of the liquid to be treated remaining in the pan 4 from the start of the supply of the diluting liquid to the stop of the supply. Most of the solidified material is dried and solidified and removed.

After supplying the diluent for a certain period of time, the on-off valve 15
Is closed, the on-off valve 14 is opened, and the liquid to be treated is supplied into the pan 4. Thereafter, similarly, the processing is performed by alternately supplying the liquid to be treated and the diluting liquid at a predetermined time interval.

In another example of the method of the present invention, the processing is performed while supplying the liquid to be treated and intermittently supplying the diluting liquid into the pan using the apparatus having the flow shown in FIG. That is, while the liquid to be treated in the liquid to be treated storage tank 11 is supplied into the pan 4 by the liquid feed pump 16A via the on-off valve 14, the diluent in the diluent liquid storage tank 13 is supplied via the on-off valve 15. The process is performed by intermittently supplying the liquid by the liquid sending pump 16B. In this case, the supply interval, supply time, supply amount, and the like of the diluting liquid may be appropriately determined based on, for example, the water content of the liquid to be treated 5 in the bread as in the case of the above-described alternate supply.

When the diluting liquid is intermittently supplied while supplying the liquid 5 to be processed into the pan as in this embodiment, the diluting liquid is supplied if the processing liquid 5 is always supplied at a constant flow rate. In such a case, the liquid to be treated may overflow from the pan 4,
When supplying the diluent, it is preferable to temporarily reduce the supply of the liquid to be treated by an amount corresponding to the supply of the diluent.

[0030]

Next, the present invention will be described in more detail with reference to specific examples. Example 1 A dip-type drum dryer was used to adjust the drum surface temperature to 13.
Operation was performed at 0 ° C. and a rotation speed of 5 rpm, and glycerin (boiling point: 2
(90 ° C.) and a treatment liquid containing 2 wt% of other salts and 40 wt% of other salts. The liquid to be treated is 30kg
/ M ² · h for 120 minutes, supply of the liquid to be treated is stopped, and instead of the liquid to be treated, water (diluent) is supplied at a supply speed of 30 kg / m ² · h for 15 minutes. After the supply operation is repeated three times, the liquid to be treated is further
Minutes (total processing time 525 minutes). In addition, diatomaceous earth was previously added to the liquid to be treated and the diluting liquid such that the content was 10% by weight. The time-dependent change of the water content in the liquid to be treated in the bread is indicated by a circle in FIG. As shown in FIG. 3, the moisture content in the liquid to be treated in the bread kept a value in a substantially constant range during the processing operation. The scraping property of the solid was good throughout the treatment process.

Example 2 The same liquid to be treated as in Example 1 was continuously supplied at a supply rate of 30 kg / m ² · hour, and water (diluent) was added at a rate of ² kg / m ² · hour.
When a processing operation in which a dilution operation of supplying for 15 minutes at a supply speed of 0 kg / m ² · hour was repeated at intervals of 60 minutes was performed for 285 minutes, the water content of the liquid to be processed in the bread was changed during the processing operation. , About 42 to 50%, and the scraping property of solids was good. In the step of supplying the diluent, the supply amount of the liquid to be treated was reduced by an amount corresponding to the supply amount of the diluent. Other conditions are the same as those in the first embodiment.

Comparative Example 1 The same treatment as in Example 1 was carried out under the same conditions as in Example 1, except that the liquid to be treated was continuously supplied and the supply of the diluent was not carried out. About 360 minutes after the supply of the liquid to be treated was started, the viscosity of the solid on the drum surface increased, and the workability of scraping the solid by the scraper was extremely deteriorated.

Comparative Example 2 A treatment was performed under the same conditions as in Comparative Example 1 except that diatomaceous earth was not added to the liquid to be treated and the diluent. About several tens of minutes after the supply of the liquid to be treated was started, the viscosity of the solid on the drum surface increased, and the workability of scraping the solid by the scraper was extremely deteriorated.

[0034]

As described above, according to the method of the present invention, the step of supplying the liquid to be treated and the step of stopping the supply of the liquid to be treated and supplying the diluent are alternately repeated. Alternatively, the diluting liquid is intermittently supplied together with the supply of the liquid to be treated, so that the solidified substance to be treated in the liquid to be treated in the pan is different from the conventional method of continuously supplying the liquid to be treated. There is no danger of extreme concentration. Therefore, it is not necessary to perform a troublesome operation such as stopping the supply of the liquid to be treated at regular intervals and cleaning the inside of the pan, and the processing can be performed continuously.

Further, by adding a solidifying modifier such as diatomaceous earth to the liquid to be treated and the diluting liquid, it is easy to make the solid dried and solidified on the surface of the drum easy to scrape off. In particular, when the liquid to be treated contains a high-boiling substance having a boiling point higher than the drum surface temperature, the addition of a solidification regulator is effective, and the solidification modifier is dried and solidified on the drum surface by the addition of the solidification regulator. In addition to preventing stickiness of the solid material, the high boiling substance can be easily adhered to the drum by the solidification modifier, thereby improving the processing efficiency.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a flow of a dip type drum dryer device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing another example of the flow of the dip type drum dryer device according to the embodiment of the present invention.

FIG. 3 is a graph showing the change over time in the water content of the liquid to be treated in the bread in the test of Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dip type drum dryer 2 Casing 3 Drum 4 Pan 5 Liquid to be processed 6 Stirrer 11 Liquid storage tank 13 Diluent storage tank

Claims (4)

(57) [Claims] 1. A liquid to be treated containing a substance to be solidified is supplied into a pan of a dip-type drum dryer, and the liquid to be treated is brought into contact with a drum rotating in the pan to form a liquid on the surface of the drum. In a method for treating a liquid containing a solidified substance by a dipping drum dryer, the liquid to be treated is dried by a heating means to solidify the substance to be solidified. A step of supplying a liquid to be treated containing a solidification treatment substance, and a step of stopping supply of the liquid to be treated and supplying a diluting liquid into a pan, wherein the step is alternately and repeatedly performed. A method for treating a liquid containing a substance to be solidified by a dryer. 2. A liquid to be treated containing a substance to be solidified is supplied into a pan of a dip-type drum dryer, and the liquid to be treated is brought into contact with a drum rotating in the pan to apply the liquid to the drum surface. In the method of treating a liquid containing a substance to be solidified by a dipping drum dryer, the liquid to be treated is solidified by drying the liquid to be treated by heating means and solidifying the substance to be solidified. A method for treating a liquid containing a substance to be solidified by a dip-type drum dryer, wherein the liquid to be treated containing the chemical substance to be treated is supplied and the diluent is intermittently supplied into the pan. 3. The method for treating a liquid containing a substance to be solidified by a dip-type drum dryer according to claim 1, wherein a solidification modifier is added to the liquid to be treated and the diluting liquid. . 4. The method for treating a liquid containing a substance to be solidified by a dip-type drum dryer according to claim 1, wherein the liquid to be treated contains a high-boiling substance.