TW201625778A - Oil-water separation method for water-containing coal tar and oil-water separation agent - Google Patents

Abstract

Provided is an oil-water separation method for water-containing coal tar, the method is excellent in oil-water separating effects. The oil-water separation method for water-containing coal tar separates oil and water by adding, to a water-containing coal tar, at least one surfactants selected from the group consisting of a nonionic surfactant having a Griffin method HLB value of at least 6.5 and an anionic surfactant having a Davies' method HLB value of at least 45, said water-containing coal tar contains, in a mass ratio, at most one part of water with respect to one part of coal tar.

Description

Oil-water separation method for water-containing coal tar and oil-water separating agent

The invention relates to an oil-water separation method for an aqueous coal tar and an oil-water separating agent.

Coal tar (hereinafter also referred to as "tar") is a by-product produced from a coke oven and is produced in the following manner. Ammonia water is dispersed in the gas generated in the coke oven and cooled, and the obtained condensate is placed in a tar decanter together with ammonia water to separate into an ammonia water layer and a tar layer, and the tar is extracted and charged. In the oil tank (the crude purified product storage tank after the decanter was separated), ammonia water was taken out and placed in an ammonia water tank. Since the tar in the tar tank contains sludge, the sludge is separated by a centrifugal separator (super decanter), and the obtained tar is placed in a tar storage tank (a storage tank of a highly purified tar after centrifugation). Coal tar is formed into a latex in a water-containing state. Therefore, in the production and purification steps of coal tar, oil-water separation is required in a tar decanter, a tar tank, a centrifugal separator (super decanter), and the like. However, since the heavy oil in the coal tar has a large specific gravity, has a high affinity with water, and forms a strong latex in a water-containing state, it is not easily separated even by the centrifugal separation method.

Patent Document 1 discloses a method of adding an alkylallylsulfonate, an alkanesulfonate, a higher alcohol sulfate, or a polyoxyethylene alkylbenzene to an aqueous waste oil containing a heavy oil of a coal tar main body. One or more anionic surfactants of a sulfamate salt and a polyoxyethylene alkyl sulfate salt, but the degree of separation of oil and water is not sufficient. Further, there is no description about the case where the oil-water separation effect differs depending on the added portion of the chemical in the coal tar production step.

Patent Document 2 describes a method in which petroleum is added to a tar-based aqueous waste oil, and a cationic surfactant having a quaternary ammonium salt or an imidazole derivative as a main component is added to separate the oil component from the water, but the oil and water are separated. The effect is not sufficient. Further, it is also described that the anionic surfactant does not exhibit a good separation effect, and the difference between the added portion of the chemical in the coal tar production step and the oil-water separation effect is not described.

Further, Patent Document 3 discloses a method of emulsification and disintegration of a trace amount of a mixture of a formalin condensate of an alkylphenol and a polymerized ether, etc., when it is separated into coal tar and ammonia by a tar decanter. The agent is added to the tar decanter, and the residue which disintegrates the latex of the interface and is suspended in the ammonia water is removed. However, the effect of reducing the moisture in the tar is not mentioned. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. JP-A No. Hei. No. Hei. No. Hei. No. Hei.

[Problems to be solved by the invention]

An object of the present invention is to provide an oil-water separation method and an oil-water separation agent which are excellent in oil-water separation effect of water-containing coal tar. [Means for solving the problem]

In order to solve the above problem, it was found that a nonionic surfactant selected from a Griffin method having a hydrophilic-lipophile balance (HLB) value of 6.5 or more was used. One or more surfactants in a group consisting of an anionic surfactant having an HLB value of 45 or more in a Davies method, added to an aqueous coal tar, the aqueous coal tar being relative to 1 part of coal The tar contains water in a mass ratio of 1 part or less, and exhibits an excellent oil-water separation effect, thereby completing the present invention.

That is, the present invention provides the following oil-water separation method and oil-water separation agent. [1] A method for separating oil-water from aqueous coal tar, which comprises a nonionic surfactant selected from a Griffin method having an HLB value of 6.5 or more and an anionic surfactant having a Davis method having an HLB value of 45 or more. One or more surfactants in the group are added to the aqueous coal tar to perform oil-water separation, and the water-containing coal tar contains water in a mass ratio of 1 part or less with respect to 1 part of coal tar. [2] The oil-water separation method according to [1], wherein the nonionic surfactant has a Griffin HLB value of 7 or more. [3] The oil-water separation method according to [1] or [2], wherein the anionic surfactant has a Davis HLB value of 54 or more. [4] The oil-water separation method according to any one of [1] to [3], wherein the aqueous coal tar is a moisture content of 0.7 part or less with respect to 1 part of coal tar. [5] The oil-water separation method according to any one of [1] to [4] wherein the amount of the surfactant added is 0.005 mass% to 1 mass% with respect to the tar purity. [6] An oil-water separating agent for coal tar, comprising: a nonionic surfactant selected from a Griffin method having an HLB value of 6.5 or more and an anionic surfactant having a Davis method having an HLB value of 45 or more; More than one surfactant in the group. [7] The oil-water separating agent for coal tar according to [6], wherein the nonionic surfactant has a Griffin HLB value of 7 or more. [8] The oil-water separating agent for coal tar according to [6], wherein the anionic surfactant has a Davis HLB value of 54 or more. [Effects of the Invention]

According to the oil-water separation method of the aqueous coal tar and the oil-water separating agent of the present invention, the oil-water separation effect of the aqueous coal tar is excellent, the moisture of the coal tar is sufficiently reduced, and a tar product having stable quality can be obtained. The addition portion may be a portion having a large amount of coal tar component compared with moisture, and particularly used for coal tar separated by a tar decanter, and is suitable as a method for promoting dehydration in a super decanter (centrifugal separator).

The invention relates to an oil-water separation method for an aqueous coal tar and an oil-water separating agent. The oil-water separating agent for the aqueous coal tar used in the present invention is selected from the group consisting of a nonionic surfactant having a HLB value of 6.5 or more by a Griffin method and an anionic surfactant having a Davis method having an HLB value of 45 or more. One or more surfactants in the group exhibit sufficient oil-water separation effect on the aqueous coal tar containing water in a mass ratio of 1 part or less with respect to 1 part of coal tar, particularly the water-containing coal tar at the outlet of the tar decanter . In addition, in the present specification, the term "moisture" is a concept including industrial water or tap water for washing in order to remove salt from crude tar, in addition to ammonia water.

The nonionic surfactant used in the present invention requires the Griffin method to have an HLB value of 6.5 or more, preferably 7.0 or more. If the nonionic surfactant is the one having the HLB value, the type is not limited. Preferably, a polyoxyalkylene alkyl ether or a polyoxyethylene polyoxypropylene block polymer is used.

The polyoxyalkylene alkyl ether having the Hurricane HLB value as described above generally has an alkyl group having a carbon number of 8 to 12, a polyoxyalkylene group, a polyoxyethylene group, and an addition of ethylene oxide. Obtained in the range of 16 to 25 ears. Specific examples of the polyoxyalkylene alkyl ether used in the present invention include a polyoxyalkylene alkyl ether having an HLB value of 11 (trade name "SANNONIC SS-50"). Sanyo Chemical Industry Co., Ltd. manufactures).

The polyoxyethylene polyoxypropylene block polymer is a polyethylene oxide-polypropylene oxide-polyethylene oxide obtained by polymerizing ethylene oxide on a polypropylene glycol obtained by polymerization of propylene oxide. The triblock copolymer has different HLB values depending on the degree of polymerization of polyethylene oxide and polypropylene oxide (usually several tens of each). Specific examples of the polyoxyethylene polyoxypropylene block polymer used in the present invention include a polyoxyethylene polyoxypropylene block polymer having an HLB value of 7 (trade name "NEWPOL" PE. -74", manufactured by Sanyo Chemical Industry Co., Ltd.), a polyoxyethylene polyoxypropylene block polymer having an HLB value of 16 (trade name "NEWPOL PE-78", manufactured by Sanyo Chemical Industry Co., Ltd. )Wait.

In the nonionic surfactants having an HLB value of less than 6.5 by the Griffin method used in Comparative Example 13 and Comparative Example 14, which are described later, the oil-water separation effect is poor, and even if the Griffin method is used, the HLB value is 6.5 or more. The nonionic surfactant has a poor oil-water separation effect for a mixture of coal tar and water having more moisture than the coal tar component.

The anionic surfactant used in the present invention needs to have an HLB value of 45 or more, preferably 54 or more, calculated by the Davis method, and the anionic surfactant preferably has the HLB value of the Davis method. Polyoxyalkylene alkyl sulfosuccinate, sulfosuccinate alkyl salt.

In the polyoxyalkylene alkyl sulfosuccinate, the polyoxyalkylene group of the polyoxyalkylene alkyl group is polyoxyethylene or polyoxypropylene, and the average addition molar number thereof is preferably about 1 to 2, the alkyl group of the polyoxyalkylene alkyl group has a carbon number of 10 to 18, preferably 12 to 14, and the sulfosuccinate salt is a sulfosuccinic acid dibasic metal salt or a sulfosuccinic acid Ammonium salt. Specific examples of the polyoxyalkylene alkylsulfonated succinate used in the present invention include a polyoxyethylene (about 2) alkyl group (12 to 14) having a Davis method having an HLB value of 56. Disodium sulfosuccinate (trade name "BEAULIGHT ESS", manufactured by Sanyo Chemical Industry Co., Ltd.) and the like.

In the alkyl salt of sulfosuccinic acid, the alkyl group has a carbon number of 10 to 18, preferably 12 to 14, and the sulfosuccinate is a sulfosuccinate dibasic metal salt or a sulfosuccinic acid II. Ammonium salt. Specific examples of the sulfosuccinic acid alkyl salt used in the present invention include, for example, a Daeves method of sulphosuccinic acid disodium sulphate having a HLB value of 54 (trade name "BEAULIGHT" SSS", manufactured by Sanyo Chemical Industry Co., Ltd.).

In the anionic surfactant having a Davis method HLB value of less than 45 used in Comparative Example 11 and Comparative Example 12 described later, the oil-water separation effect is poor, and an anion having an HLB value of 45 or more is used even if the Davis method is used. A surfactant is a poor oil-water separation effect for a mixture of coal tar and water having a moisture content greater than that of a coal tar component. Incidentally, the Davis sodium sulfate as a representative anionic surfactant has a Davis method HLB value of 40.

Adding all of the surfactants of the group consisting of a nonionic surfactant having a HLB value of 6.5 or more and an anionic surfactant having a Davis method having an HLB value of 45 or more The amount is preferably from 0.005 mass% to 1 mass%, more preferably from 0.01 mass% to 0.1 mass%, based on the tar purity. Further, when the nonionic surfactant is added to the main body, the amount thereof is preferably 70% by mass or more of all the surfactants.

The above surfactant may be directly added with a solid such as disodium polyoxyethylene sulfosuccinate or disodium laurate succinate, and it is desirable to take into consideration the mixing and homogenization in the water-containing coal tar to be used. It is added in liquid form for dilution with water.

In the oil-water separation method and the oil-water separation agent of the present invention, in the step of producing the coal tar, the addition portion of the oil-water separating agent may be a portion having a large amount of coal tar component compared with water, and is preferably added to 1 part of coal. The tar and the aqueous coal tar containing water in a mass ratio of 0.7 parts or less, particularly the coal tar separated by the tar decanter, is suitable as a method for promoting dehydration in a super decanter (centrifugal separator).

Coal tar retains moisture as a W/O type latex, so in order to separate coal tar from water, it is necessary to disintegrate the latex. In the present invention, when a specific surfactant as a water-oil separating agent is added, the interface of the latex is formed and the latex is not maintained. Therefore, it is considered that the water is combined and separated into water and tar. A nonionic surfactant having an HLB value of 6.5 or more in the Griffin method and an anionic surfactant having an HLB value of 45 or more in the Davis method are easily dissolved in water, but are difficult to be dissolved and diffused in the tar. Therefore, among the aqueous coal tars having a water content of 1 or less with respect to the tar 1, the surfactants can concentrate on the moisture present in the form of a latex in the tar and the interface thereof. Therefore, it is considered that, in the portion where the water is more than the tar, for example, the surfactant is added to the mixture of the tar and the ammonia (the tar: ammonia water = about 1:500) on the inlet side of the tar decanter, and is added to the tar. In the case where the tar (the tar: moisture = 1:0.1 to 1.0) having a small amount of water after being treated by the tar decanter at the outlet of the separator, a high oil-water separation effect can be exhibited with a surfactant having a small added amount. [Examples]

The invention will be further described in detail by way of examples, but the invention is not limited by the examples.

Examples 1 to 10, Comparative Examples 1 to 14 (tar): tar (water content: 16%, tar component: moisture = 1:0.2) at the outlet of the tar decanter was used. (Amount of addition of oil-water separating agent): Various surfactants as an oil-water separating agent were added so that the total interface active amount was 0.020% by mass based on the tar purity. Furthermore, the Davis method HLB value of the anionic surfactant is a calculated value derived from the drug structure using the Davis formula. (test sequence): The coal tar was placed in a 70 ° C thermostatic bath to raise the temperature. 100 g of coal tar was separated from the sample vial to prepare aqueous coal tar without adding pure water and 40 g and 144 g were added. 464 g of pure water-containing coal tar (mixture of coal tar and water) (tar: moisture ratios are 1:0.2, 1:0.7, 1:1.9, 1:5.7, respectively). A quantitative amount of surfactant is added to the obtained mixture of coal tar and water using a micropipette. The mixture was stirred for 1 minute with a spatula and allowed to stand in a 70 ° C thermostat for 3 hours. Then, the appearance was visually observed, the amount of separated water was measured, and the oil-water separation effect was evaluated. (Evaluation): It was confirmed that the moisture present in the tar was separated by a few percent based on the amount of water in the aqueous phase after centrifugation. A... 40% or more of the separated water amount B... 20% or more and less than 40% of the separated water amount C... Less than 20% of the separated water amount The test results are shown in Table 1.

Table 1

In Examples 1 to 10 (a specific surfactant was added to a water-containing coal tar containing 1 part or less of water in a mass ratio of 1 part or less), a remarkable oil-water separation effect was confirmed. Since the surfactant used here is easily dissolved in water and is difficult to be dissolved and diffused in tar, it is considered that it is possible to concentrate on water and its interface which are formed by the formation of latex in tar. However, these surfactants also exhibited a significant decrease in the oil-water separation effect in the tar/water mixture having a large amount of water in Comparative Examples 1 to 10. The ratio of surfactant to water is reduced, resulting in a decrease in the amount of interfacial activity in the latex that acts on moisture, and therefore the effect of oil-water separation is considered to be reduced.

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Claims (8)

An oil-water separation method for a water-containing coal tar, which comprises a group consisting of a nonionic surfactant having a HLB value of 6.5 or more by a Griffin method and an anionic surfactant having a Davis method having an HLB value of 45 or more. One or more of the surfactants are added to the aqueous coal tar to perform oil-water separation, and the aqueous coal tar contains water in a mass ratio of 1 part or less with respect to 1 part of coal tar. The oil-water separation method according to claim 1, wherein the nonionic surfactant has a Griffin HLB value of 7 or more. The oil-water separation method according to the first or second aspect of the invention, wherein the anionic surfactant has a Davis HLB value of 54 or more. The oil-water separation method according to any one of the items 1 to 3, wherein the water-containing coal tar is water-containing in a mass ratio of 0.7 part or less with respect to 1 part of coal tar. The oil-water separation method according to any one of claims 1 to 4, wherein the amount of the surfactant added is 0.005 mass% to 1 mass% with respect to the tar purity. An oil-water separating agent for coal tar, comprising a group selected from the group consisting of a nonionic surfactant having a HLB value of 6.5 or more by a Griffin method and an anionic surfactant having a Davis method having an HLB value of 45 or more. More than one surfactant. The oil-water separating agent for coal tar according to claim 6, wherein the nonionic surfactant has a Griffin HLB value of 7 or more. The oil-water separating agent for coal tar according to claim 6 or 7, wherein the anionic surfactant has a Davis HLB value of 54 or more.