JP2003053400A - Sludge dewatering agent and sludge dewatering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modified polyalkyleneimine which has good water filtra tion properties as a polyalkyleneimine-base sludge dewatering agent, can lower the moisture content of filter cake, facilitates the reaction control in modifica tion and is good in the stability of a product without lowering cation density and a method of efficiently dewatering organic sludge by using the same. SOLUTION: The sludge dewatering agent consists of the modified polyalkyleneimine of general formula 1 and/or 2 (n is an integer of >=0 and R1 to R9 are hydrogen, 1-3C alkyl groups, hydroxyalkyl groups or benzyl groups). The method of producing the modified polyalkyleneimine comprises reacting the polyalkyleneimine or a mixture composed of the polyalkyleneimine and a polyamine with a corresponding polycation material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sludge dewatering agent and a sludge dewatering method, and more particularly to a sludge dewatering agent composed of a polyalkyleneimine modified product having a specific structural unit. After adding
The present invention relates to a method for dehydrating sludge, which comprises dehydrating with a dehydrator.

[0002]

2. Description of the Related Art Conventionally, a polymer or copolymer of an acrylic cationic monomer has been used as a dehydration treatment for sludge. However, the acrylic polymer has a high molecular weight and therefore has good coagulation performance. However, since it has a high molecular weight, the viscosity of the solution increases and the cohesion of the flocculated sludge flocs becomes high. Therefore, depending on the dewatering machine such as a belt press, there is a model that dislikes stickiness of sludge and does not sufficiently improve dewatering efficiency, and a different type of coagulant may be required. In addition, since many quaternary ammonium bases are present in the molecule, the hydrophilicity becomes high, and the water content of the dehydrated cake basically does not decrease. Furthermore, if the cation equivalence value per unit mass is relatively low and the anion equivalence value such as spoiled sludge or food-related sludge is high, it may not be possible to respond.

In such a case, a polyethyleneimine type flocculant is used. Polyethyleneimine-based flocculants have high cation equivalents, but have low molecular weights, and their flocculation performance is not sufficient. Since it is difficult to obtain a polymer having a high molecular weight, studies have been made on increasing the molecular weight by connecting or crosslinking the molecules. Techniques for increasing the molecular weight of polyethyleneimine by epichlorohydrin cross-linking are known, and there are those in which polyethyleneimine is reacted with a monoepoxy compound and then with a polyepoxy compound (JP-A-58-162682). However, the method of crosslinking polyethyleneimine with epichlorohydrin is difficult to control, and the cation equivalent of the modified product also decreases.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to develop a polyethylenedimine-based sludge dehydrating agent for use in a belt press, a filter press, etc., which is easy to control the reaction and can be modified to modify a cation or the like. The aim is to develop a polyethyleneimine-based sludge dewatering agent with little reduction in volume.

[0005]

The inventor of the present invention has made extensive studies in order to solve the above-mentioned problems and, as a result, has reached the following invention. That is, the invention of claim 1 of the present invention is a sludge dehydrating agent comprising a modified polyalkyleneimine having a structural unit represented by the following general formula (1) and / or (2).

[Chemical 1] However, n in the formulas (1) and (2) is an integer of 0 or more,
R1 to R9 are hydrogen, or an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group or a benzyl group.

According to a second aspect of the present invention, the modified polyalkyleneimine comprises a polyalkyleneimine or a mixture of polyalkyleneimine and polyamine, and a polycationic substance represented by the following general formulas (3) and / or (4). The sludge dehydrating agent comprising the modified polyalkyleneimine according to claim 1, which is a reaction product.

[Chemical 2] It is an alkyl group or a benzyl group of the numbers 1 to 3. However,
N in the formulas (3) and (4) is an integer of 0 or more, and R10
~ R18 is hydrogen or alkyl go of 1 to 3 carbons, hydroxyalkyl go or benzyl go

The invention of claim 3 is characterized in that the modified polyalkyleneimine is crosslinked by the polycationic substance (3), and the sludge dehydration comprising the modified polyalkyleneimine according to claim 1 is carried out. It is an agent.

According to a fourth aspect of the present invention, the polycationic substance comprises one or more amines selected from ammonia, an aliphatic primary amine, an aliphatic secondary amine and an aliphatic tertiary amine, and epihalohydrin. A sludge dehydrating agent comprising a polyalkyleneimine modified product according to claim 1 or 2, which is a polycondensate.

According to a fifth aspect of the present invention, the polycationic substance is epihalohydrin A (mol), ammonia,
When B (mol) is one or more amines selected from primary amine, secondary amine, and tertiary amine, A / B
It is a polycondensation product reacted in the range of 0.25 to 1.2, and is a sludge dehydrating agent consisting of a modified polyalkyleneimine product according to claim 4.

According to the invention of claim 6, the amino group in the polyalkyleneimine or the mixture of the polyalkyleneimine and the polyamine is C (mol), the above general formula (3) and / or
Alternatively, when the halohydrin group and / or the epoxy group in the polycationic substance represented by (4) is D (mol),
The sludge dehydrating agent comprising the modified polyalkyleneimine according to claim 1 or 2, which reacts in the range of C / D = 5 to 300 (mol%).

The invention of claim 7 is the sludge dehydrating agent comprising the modified polyalkyleneimine according to claim 1, wherein the polyalkyleneimine is polyethyleneimine.

According to the invention of claim 8, the sludge dehydrating agent comprising the modified polyalkyleneimine according to any one of claims 1 to 7 is added to and mixed with the organic sludge to coagulate the sludge, followed by dehydration with a dehydrator. It is a characteristic sludge dewatering method.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The modified polyalkyleneimine of the present invention is obtained by modifying polyalkyleneimine by a crosslinking reaction or a graft reaction with a specific polycationic substance. Hereinafter, these modified polyalkyleneimines and the modification method thereof will be described in detail. The polycationic substance used for modification is produced by reacting one or more amines selected from ammonia and aliphatic primary to tertiary amines (hereinafter referred to as primary amines) with epihalohydrin. can do. The method for producing the polycationic substance in the present invention is not particularly limited, and for example, epihalohydrin is added dropwise to one or more amines selected from ammonia, primary amines, secondary amines, and tertiary amines for reaction. can do. In the present invention, it is preferable that epihalohydrin is charged into a reactor and one or more amines selected from ammonia, primary amine, secondary amine, and tertiary amine are added dropwise to react.

The polycationic substance used in the present invention has a molar ratio of one or more amines selected from ammonia, primary amines, secondary amines and tertiary amines to epihalohydrin in a desired polyalkylene. It is appropriately selected depending on the properties, structure, molecular weight and the like of the imine-modified product, but it is generally in the range of 0.25 to 1.20. When the molar ratio of one or more amines selected from ammonia, primary amine, secondary amine, and tertiary amine to epihalohydrin is 0.25 or less, epihalohydrin remains. 1 selected from ammonia, primary amine, secondary amine, and tertiary amine for epihalohydrin
When the molar ratio of one or more amines is 1.20 or more, it is obtained by a reaction of epihalohydrin and one or more amines selected from ammonia, primary amine, secondary amine, and tertiary amine. There is no halohydrin group at the end of the polyacation material and it does not react with polyalkyleneimine or a mixture of polyalkyleneimine and polyamine.

The polycationic substance used in the present invention has a cross-linking action represented by the general formula (3), which has reactivity at both ends, and a one-end reactive substance represented by the general formula (4). Some have a graft reaction action. The former, which has a cross-linking action, is ammonia for epihalohydrin,
The molar ratio of one or more amines selected from primary amine, secondary amine, and tertiary amine is about 0.25 to
When the reaction is carried out in the range of 0.9, the production ratio of the polycationic substance represented by the general formula (3) is high, and the latter one having a grafting action is ammonia to epihalohydrin,
The molar ratio of one or more amines selected from primary amines, secondary amines, and tertiary amines is about 0.8-1.
When the reaction is carried out in the range of 2, the production ratio of the polycationic substance represented by the general formula (4) becomes high.

A method for producing a modified product produced by the reaction of the polyalkyleneimine (C) or the mixture of polyalkyleneimine and polyamine with the polycationic substance represented by the general formula (3) and / or (4) in the present invention. Is not particularly limited, and can be produced, for example, by adding the cationic substance represented by the general formula (3) and / or (4) to polyalkyleneimine or a mixture of polyalkyleneimine and polyamine and reacting them. Alternatively, the reaction can be carried out by adding polyalkyleneimine or a mixture of polyalkyleneimine and polyamine to the cationic substance represented by the general formula (3) and / or (4).

The method for controlling the reaction is not particularly limited and includes, for example, polyalkyleneimine as a raw material or a mixture of polyalkyleneimine and polyamine as a raw material, or a polycation represented by the general formula (3) and / or (4) before the reaction. The reaction rate can be reduced by previously diluting a mixture of substances with ion-exchanged water or the like to cause a reaction. Alternatively,
It is also possible to control the reaction rate while diluting during the reaction. In addition, in order to obtain a reaction product having a desired product viscosity, acids such as sulfuric acid and hydrochloric acid may be added during the reaction to stop the reaction.

Generally, epihalohydrin and ammonia,
Aliphatic primary amine to tertiary amine can easily react to obtain a polycationic substance. Such amines are ammonia, aliphatic monovalent amines and aliphatic polyamines. Examples of the aliphatic monovalent amine include monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, and n.
-Butylamine or isobutylamine.
Aliphatic polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, hexamethylenediamine and the like. Particularly preferred among these monovalent or polyamines are:
It is monomethylamine, dimethylamine, trimethylamine, ethylenediamine or pentaethylenehexamine.

The temperature range in which the reaction of epihalohydrin and amines is carried out is appropriately selected according to the properties, structure, molecular weight and the like of the polyalkyleneimine modified product desired in the subsequent modification reaction, but generally 10 to 90 ° C. Preferably 2
It is in the range of 0 to 60 ° C. When the reaction temperature is 20 ° C or lower, the reaction rate is slow and not practical, and when it is 60 ° C or higher, the polyhalogenated terminal halohydrin group or epoxy go obtained by the reaction of epihalohydrin with ammonia or monovalent aliphatic or polyamine is hydrolyzed. As a result, the reactivity between the polyalkyleneimine or the polyalkyleneimine and the polyamine mixture is lost.

Further, the temperature range in which the reaction of the polyalkyleneimine or the mixture of the polyalkyleneimine and the polyamine and (D) the polycationic substance represented by the general formula (3) and / or (4) is carried out is desired. The alkyleneimine modified product is appropriately selected depending on the properties, structure, molecular weight, etc., but is generally 10 to 90 ° C., preferably 20 to 90 ° C.
It is in the range of 70 ° C. Further, in order to improve the reactivity with the polycationic substance, the reaction can be carried out by adding an alkali catalyst such as sodium hydroxide in a molar ratio of 1.0 or less to epihalohydrin.

The molar ratio in the modification reaction is within the following range. That is, the amino group in the polyalkyleneimine or the mixture of polyalkyleneimine and polyamine is C (mol unit), and the halohydrin group in the polycationic substance represented by the general formula (3) and / or (4) If the epoxy group is D (molar unit), C
/ D = reacts in the range of 5 to 300 (mol%). For example, when the molecular weight of polyalkyleneimine is as high as tens of thousands to hundreds of thousands, especially when the polycationic substance represented by the above general formula (3) is mixed in at a high ratio, the crosslinking reaction proceeds too much and It becomes insoluble in water. Therefore, the filling mol% is usually 5 to 50 mol%, preferably 5
~ 30 mol%. On the other hand, when the molecular weight of the polyalkyleneimine is low such as 1,000 to 10,000, the mol% to be incorporated is usually 50 to 300 mol%, preferably 70 to 150 mol%.

The mixing ratio of the polyalkyleneimine and the polyamine mixture is not particularly limited and may be appropriately selected depending on the properties, structure, molecular weight and the like of the desired polyalkyleneimine modified product. It is in the range of 0 to 50% by weight, preferably 0 to 30% by weight.

A major feature of the modified polyalkyleneimine according to the present invention relates to various uses by partially crosslinking or grafting polyalkyleneimine or polyamine with a polycationic substance to increase the molecular weight and to make the polymer three-dimensional. It is a function improvement. The characteristics of the modified polyalkyleneimine according to the present invention have succeeded in further increasing the cohesive force and the like without impairing the conventional properties of the polyalkyleneimine. That is, in the polyalkyleneimine, primary to tertiary amino groups are present in the molecule centering on the primary amino group. When used for applications such as wastewater treatment, papermaking chemicals or surface coating, cationic dissociation disappears in the high pH region. As a result, the range of use is limited so far. However, the polycationic substance represented by the general formula (3) and / or (4) has a quaternary amino group, and the modified quaternary amino group is introduced so that the range of use is expanded. become. In particular, it exerts a remarkable effect on sludge having a high anion equivalent value such as spoilage sludge and food-related sludge. Since the modified polyethyleneimine of the present invention has a lower viscosity than an acrylic polymer, it has no tackiness of coagulated sludge and is suitable for a dehydrating agent such as a belt press. Further, as a result of the introduction of the quaternary ammonium salt group after modification, it can be applied to sludge having a wide pH range.

[0024]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

(Synthesis Example 1) 146.6 g of epichlorohydrin and 29.6 g of ion-exchanged water were charged in a 4-neck separable flask equipped with a thermometer, a stirrer and a dropping funnel.
40% of 123.8 g of a 50 wt% aqueous solution of dimethylamine
Add dropwise at ~ 45 ° C over 2 hours, then at 45 ° C for 1 hour after completion of the addition.
After reacting for 2 hours, 29.6 g of ion-exchanged water was added. As a result of colloid titration, the reaction rate of dimethylamine was 100.0%. As a result of neutralization titration of amine, the content of tertiary amine was 0.4330%, and the amount of residual epichlorohydrin measured by gas chromatography was 0%.

(Synthesis Example 2) In a 4-neck separable flask equipped with a thermometer, a stirrer and a dropping funnel, 87.5 g of 54% 3-chloro-2-hydroxypropyltrimethylammonium chloride and a 20% aqueous sodium hydroxide solution were added. 44.2 g was added and stirred for 30 minutes, 36% hydrochloric acid 8.3 g
Add to neutralize. 172g of epichlorohydrin there
Was charged, and a 50 wt% aqueous solution of dimethylamine 167.
6 g was added dropwise at 40 to 45 ° C over 2 hours, and after completion of the addition, reaction was carried out at 45 ° C for 1 hour. As a result of colloid titration, the reaction rate of dimethylamine was 100.0%.
was. As a result of neutralization titration of amine, the content of tertiary amine was 0.4330%, and the amount of residual epichlorohydrin measured by gas chromatography was 0%.

(Synthesis Example 3) Next, in a separable flask equipped with a thermometer and a stirrer, polyethyleneimine P-1050 (molecular weight 70,000) manufactured by Nippon Shokubai Co., Ltd., 50% product, was prepared.
After adding 66.7 g and ion-exchanged water 66.7 g and stirring,
9.6 g of the polycation product of Synthesis Example 1 was added, and the temperature was 60 ° C.
And reacted for 4 hours. After the reaction, 16 g of ion-exchanged water was added to make the final concentration 39%.

When the molecular weight of this reaction product was measured by gel permeation chromatography, the following chart (FIG. 1) was obtained. The cation equivalent value in colloid titration was 18.62 meq / g. Also,
The solution viscosity was measured at a polymer concentration of 28%. This sample is referred to as prototype-1.

The viscosity of the aqueous solution was measured using a Brookfield rotary viscometer. (Weight average molecular weight) The weight average molecular weight was measured by gel permeation chromatography and calculated as a polyacrylamide-equivalent molecular weight. The columns used are TOSOH and TSKge
1, the calculation was performed by GMPW by excluding the polymer below the exclusion limit of the column. The results are shown in Table 1.

(Synthesis Example 4) In a separable flask equipped with a thermometer and a stirrer, polyethylene imine SP-200 (molecular weight 10,000) manufactured by Nippon Shokubai Co., Ltd., 23.33 g of 100% product and 60 g of ion exchanged water. After addition and stirring,
26.86 g of the polycation product of Synthesis Example 1 was added and reacted at room temperature for 45 minutes. When an increase in the viscosity of the reaction product was observed, 4.5 g of 75% sulfuric acid was added to stop the reaction,
Deionized water (35.31 g) was added to adjust the concentration to 28%. The weight average molecular weight (weight average molecular weight) was measured by gel permeation chromatography in the same manner as in Synthesis Example 3 and calculated as a polyacrylamide-equivalent molecular weight (FIG. 2). In addition, molecular weight measurement and cation equivalent value were measured. This sample is referred to as prototype-2. The results are shown in Table 1.

(Synthesis Example 5) A separable flask equipped with a thermometer and a stirrer was charged with 295.6 g of 50% 50% polyethyleneimine P-1050 manufactured by Nippon Shokubai Co. and 73.89 g of ion-exchanged water and stirred. 11.81 g of the polycation product of Synthesis Example 1 was added and reacted at 60 ° C. for 30 minutes. After the reaction, 10.7 g of ion-exchanged water and 8 g of 75% sulfuric acid were added to make the final concentration 39%. The molecular weight and the cation equivalent value were measured in the same manner as in Synthesis Example 3. This sample is referred to as prototype-3. The results are shown in Table 1.

(Synthesis Example 6) In a separable flask equipped with a thermometer and a stirrer, polyethylene imine P-1050 manufactured by Nippon Shokubai Co., Ltd., 105.9 g of 50% product, 2.8 g of 100% pentaethylenehexamine and ion-exchanged water. 3
After adding 0.64 g and stirring, 4.0 g of the polycation product of Synthesis Example 1 was added, and the mixture was reacted at room temperature for 6 hours. After the reaction
Add 2.21 g of ion-exchanged water and 4.5 g of 75% sulfuric acid,
The final concentration was 39%. The molecular weight and the cation equivalent value were measured in the same manner as in Synthesis Example 3. This sample is referred to as prototype-4. The results are shown in Table 1.

(Synthesis Example 7) In a separable flask equipped with a thermometer and a stirrer, 4.0 g of the polycation product of Synthesis Example 2 was added to 100 g of 50% 50% polyethyleneimine P-1050 manufactured by Nippon Shokubai Co., Ltd. The reaction was carried out at room temperature for 6 hours. After the reaction, 8.6 g of deionized water and 4.0% of 75% sulfuric acid
g was added to bring the final concentration to 45%. The molecular weight and the cation equivalent value were measured in the same manner as in Synthesis Example 3. This sample is referred to as prototype-5. The results are shown in Table 1.

[0034]

[Table 1]

[0035]

[Figure 1]

[0036]

[Fig. 2]

[0037]

[Examples 1 to 5] Food processing wastewater excess sludge (pH 6.2)
1. Total ss 8.250 mg / mL) 200 mL was sampled into a poly beaker, and Sample-1 to Sample-5 were added to sludge solid content 1
After adding 00 ppm and carrying out beaker transfer and manual stirring 10 times, the mixture was filtered through a T-1179L filter cloth (made of nylon), and the amount of each filtrate after 10, 20 and 30 seconds was measured.
The filtered sludge is dehydrated for 1 minute at a pressing pressure of 2 Kg / m 2. Then, the filter cloth releasability and the cake self-supporting property (related to the hardness of the dehydrated cake and the water content) were visually checked. The results are shown in Table 2.

[0038]

Comparative Examples 1 to 3 Polyethyleneimine modified products (molecular weight 80,000, cation equivalent 8.3 meq / g), (Comparative-1), pre-reaction polyethyleneimine (molecular weight) were prepared by the same procedure as in Examples 1 to 5. 70,000, cation equivalent 18.6m
eq / g) (comparative-2) and polyethyleneimine neutralized product (molecular weight 70,000, cation equivalent 18.6 meq /
g) and each sample of (Comparison-3) were tested to obtain a record of each measurement item. The results are shown in Table 2.

[0039]

[Table 2] Inorganic coagulant addition amount: ppm (relative to sludge solid content), filtrate amount:
It shows that the order of mL ◎>○> Δ is good.

Claims (8)

[Claims] 1. A sludge dehydrating agent comprising a modified polyalkyleneimine having a structural unit represented by the following general formula (1) and / or (2). [Chemical 1] However, n in the formulas (1) and (2) is an integer of 0 or more,
R1 to R9 are hydrogen, or an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group or a benzyl group. 2. The modified polyalkyleneimine is a polyalkyleneimine or a mixture of polyalkyleneimine and polyamine, and the following general formulas (3) and / or (4).
The sludge dehydrating agent comprising the modified polyalkyleneimine according to claim 1, which is composed of a reaction product with a polycationic substance represented by: [Chemical 2] It is an alkyl group or a benzyl group of the numbers 1 to 3. However,
N in the formulas (3) and (4) is an integer of 0 or more, and R10
~ R18 is hydrogen or alkyl go of 1 to 3 carbons, hydroxyalkyl go or benzyl go 3. The sludge dewatering agent comprising a modified polyalkyleneimine according to claim 1, wherein the modified polyalkyleneimine is crosslinked with the polycationic substance (3). 4. The polycationic substance is a polycondensation product of epihalohydrin with one or more amines selected from ammonia, aliphatic primary amines, aliphatic secondary amines, and aliphatic tertiary amines. A sludge dehydrating agent comprising the modified polyalkyleneimine according to claim 1 or 2. 5. The polycationic substance has epihalohydrin as A (mol) and one or more amines selected from ammonia, primary amine, secondary amine and tertiary amine as B (mol). Then, A / B = 0.25-1.
A sludge dehydrating agent comprising a polyalkyleneimine modified product according to claim 4, which is a polycondensate reacted in the range of 2. 6. An amino group in polyalkyleneimine or a mixture of polyalkyleneimine and polyamine is converted to C
(Mole), C / D = 5 to 300, where D (mol) is the halohydrin group and / or epoxy group in the polycationic substance represented by the general formula (3) and / or (4).
The reaction is carried out in the range of (mol%).
Alternatively, a sludge dehydrating agent comprising the modified polyalkyleneimine according to 2. 7. The sludge dehydrating agent comprising the modified polyalkyleneimine according to claim 1, wherein the polyalkyleneimine is polyethyleneimine. 8. A sludge dewatering method, comprising adding a sludge dehydrating agent comprising the modified polyalkyleneimine product according to claim 1 to organic sludge, mixing and coagulating the sludge, and then dehydrating with a dehydrator. Method.