JPH0349605B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a new antifoaming agent and a new antifoaming method, and in particular, to a novel antifoaming agent and a new antifoaming method, which is effective at a low addition rate for the damage caused by foam that occurs in the biological treatment process of human waste treatment facilities. The present invention relates to an antifoaming agent that exhibits foam and antifoaming effects, and a defoaming method. [Conventional technology] In the biological treatment process at human waste treatment facilities, the amount and quality of treatment vary greatly depending on the season, and depending on the operating conditions, a large amount of foam may be generated, causing major operational troubles and halting operation. There are cases where this becomes difficult. In particular, recent human waste treatment facilities are increasingly adopting non-dilution, high-load treatment, which does not require dilution water, requires less installation space, and significantly reduces maintenance and management costs. However, compared to conventional methods, this method tends to foam more easily during the biological treatment process (dusting tank). Regarding the foam generated from these human waste treatment facilities,
For the purpose of foam breaking and foam suppression, compounds such as higher alcohol fatty acid esters, silicones, metal soaps, mineral oils, half esters, etc. are used singly or in combination of two or more, and each is used as an antifoaming agent depending on the processing situation. There is. In general, antifoaming agents containing surfactants include (1) antifoaming agents with propylene oxide and ethylene oxide added to higher alcohols; (2) An antifoaming agent containing a higher fatty acid ester of an ethylene oxide adduct of a higher fatty acid or a higher fatty acid ester of a propylene oxide adduct of a higher fatty acid. and so on. [Problems to be solved by the invention] In the case of the above-mentioned non-diluted high-load processing, there are
Because the sludge in the sludge tank must be maintained at a high concentration, the water temperature inside the tank is high and conditions make it easy for foaming to occur. The antifoaming agents currently used cannot be said to have sufficient foam-breaking and foam-inhibiting effects to deal with these foaming problems, and it has been necessary to increase the amount used depending on the situation. However, in the case of human waste treatment facilities, because they are used under the restricted conditions of biological treatment, the antifoaming agent used must not have a negative effect on the treatment, be inexpensive, and have an excellent antifoaming effect. . The antifoaming agents mentioned above, either alone or in combination of two or more, have excellent functions depending on their use, but when limited to antifoaming agents for human waste treatment facilities, there are several drawbacks. . For example, silicone-based compounds do not have sufficient fast-acting or long-lasting properties, and silicone oil remains attached to the inner walls of sedimentation tanks, requiring post-treatment, and mineral oil-based compounds release free oil through biological treatment. This is a cause of trouble, such as inhibiting the processing of On the other hand, the foam-breaking and foam-inhibiting effects of synthesized surfactant-based antifoaming agents vary depending on their type, form, number of moles of propylene oxide or ethylene oxide added, combination, etc., and there are problems with quick-acting, sustainability, etc. It was hot. In particular, the foaming components generated from human waste treatment facilities are thought to be caused by substances adsorbed and concentrated in activated sludge, such as extracellular polymers in activated sludge, and the foam itself is extremely sticky and defoaming. required large amounts of drugs. The present inventors have conducted various studies to solve these problems in the conventional technology, and as a result, have developed a new self-emulsifying antifoaming agent that is safe for biological treatment and has excellent foam-breaking and foam-inhibiting effects. I came to find it. [Means for Solving the Problems] The present invention has the general formula HO−[(C ₂ H ₄ O) _l −(C ₃ H ₆ O) _n −(C ₄
H ₈ O） _o 〕H…… (However, in the formula, l is 0 to 30, m is 10 to 100, n is 0
It represents an integer of ~50, R ₁ represents a C ₁₇ alkyl group or alkenyl group, and when two or more types of the above alkylene oxide groups are present, it is a block or random adduct. 1.) An antifoaming agent comprising a mixture of the compound and/or the compound represented by the following formula and the compound and/or the compound in a proportion of 5 to 55% by weight with respect to the mixture. and an antifoaming method characterized in that when adding the antifoaming agent to the foaming liquid, the antifoaming agent is added by detecting a set foam surface position. In the present invention, when l is larger than 30, the hydrophilicity becomes large, and the material becomes soluble at room temperature, and the antifoaming power is significantly reduced. Moreover, when m and n are larger than 100 and 50, respectively, the lipophilicity increases and the self-emulsifying property and diffusibility deteriorate. R ₁ of the compound represented by the general formula and
C ₁₇ H ₃₅ - represents an alkyl group or alkenyl group,
Anything other than this is not desirable. For example, when the number of carbon atoms in R ₁ is C ₁₆ or less, the antifoaming power is weak, and on the contrary, when the number of carbon atoms in R 1 is C ₁₈ or more, the self-emulsifying property becomes poor. In addition, the compounding ratio of the compound represented by the general formula and/or in the antifoaming agent may be 5 to 55% by weight, but is most preferably 10 to 50% by weight. Shows remarkable effects in action. The antifoaming agent of the present invention has the same performance whether it is used as a stock solution or emulsified in water. Further, it may be used in combination with a solvent or the like. The antifoaming agent of the present invention may be added to the liquid to be treated at a ratio of 10 mg/-30 mg/. The compound represented by the general formula used in the present invention is
It can be produced by subjecting ethylene glycol, propylene glycol, and/or butylene glycol, etc. to an addition reaction with ethylene oxide, propylene oxide, and butylene oxide in the presence of an alkali catalyst. On the other hand, the compound represented by the general formula and is the compound represented by the general formula obtained by the above method,
Through an esterification reaction with higher fatty acids in the presence of an esterification catalyst such as para-toluenesulfonic acid,
Alternatively, it can be obtained by a dehydrochloric acid reaction with a higher fatty acid clide or by a transesterification reaction using a lower alcohol higher fatty acid ester. Further, the desired product can also be obtained by immediately adding an alkylene oxide to a higher fatty acid. In addition, in the antifoaming method using the above-mentioned antifoaming agent, a foaming liquid such as human waste is biologically treated and foaming occurs and then it is added. It is preferable to control the addition so that it is added when it is detected. Examples Regarding the antifoaming effects of the antifoaming agent of the present invention and conventional products,
A comparative study was conducted using the following methods. Test method: The test device used a transparent acrylic column with a diameter of 60φ and a length of 1000 mm.A transparent acrylic column with a diameter of 100φ and a length of 800 mm was installed on the outside as a jacket for hot water in order to keep the sample warm. Batsuki adopted the defuser stone method in which air is sent out from a diffuser balloon installed at the bottom of the column. For the test, the sample is bombarded with a certain amount of air for 1 to 2 minutes, and the foamed foam is adjusted to a certain height, after which the blowing is stopped and an antifoaming agent is added to the surface of the foam. Then, the state of foam disappearance was measured (bubble breaking effect). Furthermore, after the bubbles disappeared, a certain amount of air was bubbled again, and the height of the bubbles was measured over time from immediately after the bubbles disappeared until 8 minutes later. (foam suppressing effect). As described above, the effectiveness of each antifoaming agent was comprehensively evaluated based on the foam-breaking and foam-inhibiting effects. (1) Target sample: Undiluted high-load processing dusting tank sludge (2) Test amount: 1 (3) Dusting air amount: 2/min (4) Antifoaming agent injection rate: 10mg/test defoaming There are a total of 6 types of agents, 6 types of invented products and 4 types of conventional products.
There are 10 types, detailed contents are shown in Table 1, and results are shown in Table 2.

【table】

【table】

[Table] Table 3 shows the results of a comparative study of the defoaming effects of the antifoaming agent of the present invention and conventional products in a non-dilution, high-load processing facility. In the test, the undiluted solution or antifoaming agent diluted 50 times with water was injected while the injection pump was operated on and off to maintain the foam height at a constant level using a foam meter. The results are shown in Table-3. As a result, when the product of the present invention was applied, it was 2.6 times that of the conventional product in the diluted injection method, and 1.7 times that in the undiluted solution injection method.
It has an excellent antifoaming effect and is approximately 2 times more effective than conventional products.
Similar effects were obtained with a 40-60% lower injection volume.

〔Effect of the invention〕

As detailed above, the antifoaming agent of the present invention has the following excellent effects. (1) It has excellent fast-acting properties (foam-breaking effect) and long-lasting properties (foam-inhibiting effect) against problems caused by foam generated from the dusting tank of human waste treatment facilities, and stable treatment can be expected with a small amount added. . (2) Since the present invention has excellent emulsion stability, even if it is diluted with water and used in an emulsified state, there is no difference from the undiluted solution injection method, and there is no particular problem in terms of performance. (3) The product of the present invention does not adhere to equipment or equipment due to residue, and there are no factors that inhibit biological treatment, so there is no particular problem in treatment even if it is used continuously for a long period of time.

Claims (1)

[Claims] 1 General formula HO−[(C ₂ H ₄ O) _l −(C ₃ H ₆ O) _n −(C ₄
H ₈ O） _o 〕H…… (However, in the formula, l is 0 to 30, m is 10 to 100, n is 0
It represents an integer of ~50, R ₁ represents a C ₁₇ alkyl group or alkenyl group, and when two or more types of the above alkylene oxide groups are present, it is a block or random adduct. 1.) An antifoaming agent comprising a mixture of the compound and/or the compound represented by the following formula and the compound and/or the compound in a proportion of 5 to 55% by weight with respect to the mixture. 2. A defoaming method characterized in that when adding the defoaming agent according to claim 1 to a foamable liquid, the defoaming agent is added by detecting a set foam surface position.