WO2016113987A1 - 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 excelling 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 containing, in a mass ratio, at most one part water with respect to one part coal tar, at least one surfactant 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.

Description

Oil-water separation method and oil-water separation agent for hydrous coal tar

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

Coal tar (hereinafter also referred to as “tar”) is a by-product generated from a coke oven and is produced as follows.
Aqueous water (ammonia water) is sprayed on the gas generated in the coke oven and cooled, and the resulting condensate is allowed to stand in a tar decanter together with the water to separate it into a water layer and a tar layer. Put in tar tank (crude refined product storage tank after separation of decanter), extract water and put into water tank. Since the tar in the tar tank contains sludge, the sludge is separated by a centrifuge (super decanter), and the obtained tar enters a tar storage tank (a storage tank for a highly purified tar after centrifugation).
Since coal tar forms an emulsion in a water-containing state, oil-water separation is required in a tar decanter, a tar tank, a centrifuge (super decanter) or the like in the production and purification process of coal tar. However, heavy oil in coal tar has a large specific gravity, a high affinity with water, and forms a strong emulsion in a water-containing state, so that separation is not easy even with a centrifugal separation method.

In Patent Document 1, a heavy oil mainly composed of coal tar contains water-containing waste oil containing water, an alkyl allyl sulfonate, an alkane sulfonate, a higher alcohol sulfate, a polyoxyethylene alkylphenyl sulfate salt, and a polyoxyethylene alkyl. Although a method of adding one or more anionic surfactants of sulfate salt has been described, the degree of oil-water separation has not been sufficient. Moreover, it was not described that the oil-water separation effect differs depending on the location of these drugs in the coal tar production process.

Patent Document 2 describes a method of separating oil and water by adding a cationic surfactant mainly composed of quaternary ammonium salt or imidazole derivative to tar-based hydrous waste oil. The oil / water separation effect was not sufficient. And it was described that an anionic surfactant does not show a good separation effect, and the difference between the place of addition of these drugs in the coal tar production process and the oil-water separation effect was not described.

Patent Document 3 discloses that when a tar decanter is used to separate coal tar and aqueous water, a small amount of a lipophilic demulsifier such as a mixture of an alkylphenol formalin condensate and a polymerized ether is added to the tar decanter. Describes a method for removing wrinkles suspended in aqueous water by breaking the emulsion at the interface. However, no mention is made of the effect of reducing moisture in tar.

JP-A 51-96785 JP 54-102305 A JP 2000-198986 A

An object of the present invention is to provide an oil / water separation method and an oil / water separation agent excellent in the oil / water separation effect of hydrous coal tar.

One or more interfaces selected from the group consisting of a nonionic surfactant having a Griffin method HLB value of 6.5 or more and an anionic surfactant having a Davis method HLB value of 45 or more in order to solve the above problems The present inventors have found that an excellent oil-water separation effect can be exhibited by adding an activator to a hydrous coal tar containing 1 part by weight of moisture with respect to 1 part of coal tar.

That is, the present invention provides the following oil-water separation method and oil-water separation agent.
[1] One or more surfactants selected from the group consisting of a nonionic surfactant having a Griffin method HLB value of 6.5 or more and an anionic surfactant having a Davis method HLB value of 45 or more are treated with coal tar 1 An oil-water separation method of hydrous coal tar, wherein oil-water separation is carried out by adding water to hydrous coal tar containing 1 part by weight or less of water with respect to parts.
[2] The oil-water separation method according to [1], wherein the nonionic surfactant has a Griffin method HLB value of 7 or more.
[3] The oil-water separation method according to [1] or [2] above, wherein the anionic surfactant has a Davis method HLB value of 54 or more.
[4] The oil-water separation method according to any one of the above [1] to [3], wherein the hydrous coal tar contains water in a mass ratio 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] above, wherein the addition amount of the surfactant is 0.005 to 1% by mass with respect to the pure tar content.
[6] Coal tar containing one or more surfactants selected from the group consisting of a nonionic surfactant having a Griffin method HLB value of 6.5 or more and an anionic surfactant having a Davis method HLB value of 45 or more Oil / water separator.
[7] The oil / water separator for coal tar according to [6] above, wherein the nonionic surfactant has a Griffin method HLB value of 7 or more.
[8] The oil-water separator for coal tar according to [6] or [7] above, wherein the anionic surfactant has a Davis method HLB value of 54 or more.

According to the oil-water separation method and oil-water separation agent of the hydrous coal tar of the present invention, the oil-water separation effect of the hydrous coal tar is excellent, and the moisture of the coal tar can be sufficiently reduced to obtain a stable quality tar product. It becomes. The addition part should just be a part with much coal tar content rather than a water | moisture content, and it is especially suitable as a method of using a coal tar separated with a tar decanter and promoting dehydration in a super decanter (centrifuge).

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

The nonionic surfactant used in the present invention requires a Griffin method HLB value of 6.5 or more, and preferably 7.0 or more. As such a nonionic surfactant, The type is not limited as long as it has an HLB value, but polyoxyalkylene alkyl ethers and polyoxyethylene polyoxypropylene block polymers are preferably used.

The polyoxyalkylene alkyl ether having such a Griffin method HLB value is usually an alkyl group having 8 to 12 carbon atoms, the polyoxyalkylene is polyoxyethylene, and the number of moles of ethylene oxide added is in the range of 16 to 25. Obtained from.
Specific examples of the polyoxyalkylene alkyl ether used in the present invention include, for example, a polyoxyalkylene alkyl ether having an HLB value of 11 (trade name “Sannonic SS-50”, manufactured by Sanyo Chemical Industries, Ltd.).

Polyoxyethylene polyoxypropylene block polymer is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer obtained by polymerizing ethylene oxide to polypropylene glycol obtained by polymerization of propylene oxide. Polyethylene oxide, polypropylene oxide The HLB value varies depending on the degree of polymerization (usually several tens of each).
Specific examples of the polyoxyethylene polyoxypropylene block polymer used in the present invention include, for example, a polyoxyethylene polyoxypropylene block polymer having an HLB value of 7 (trade name “New Pole PE-74”, Sanyo Chemical Industries, Ltd. And a polyoxyethylene polyoxypropylene block polymer having a HLB value of 16 (trade name “New Pole PE-78”, manufactured by Sanyo Chemical Industries, Ltd.).

A nonionic surfactant having a Griffin method HLB value of less than 6.5 as used in Comparative Examples 13 and 14 described below has a poor oil-water separation effect, and the Griffin method HLB value is 6.5 or more. Even if a nonionic surfactant is used, the oil-water separation effect is poor for a mixture of coal tar and water having a moisture content higher than that of coal tar.

The anionic surfactant used in the present invention requires an HLB value calculated by the Davis method of 45 or more, and preferably 54 or more. As such an anionic surfactant, the Davis is used. Polyoxyalkylene alkyl sulfosuccinates and sulfosuccinic acid alkyl salts having a method HLB value are preferably used.

In the polyoxyalkylene alkyl sulfosuccinate, the polyoxyalkylene of the polyoxyalkylene alkyl group is polyoxyethylene or polyoxypropylene, and the average addition mole number thereof is preferably about 1 to 2, and the polyoxyalkylene alkyl group alkyl Has a carbon number of 10 to 18, preferably 12 to 14, and the sulfosuccinic acid salt is a sulfosuccinic acid dialkali metal salt or a sulfosuccinic acid diammonium salt.
Specific examples of the polyoxyalkylene alkyl sulfosuccinate used in the present invention include, for example, polyoxyethylene (about 2) alkyl (12 to 14) disodium sulfosuccinate having a HLB value of 56 (trade name “View” Light ESS ", manufactured by Sanyo Chemical Industries, Ltd.) and the like.

In the sulfosuccinic acid alkyl salt, the alkyl group has 10 to 18, preferably 12 to 14 carbon atoms, and the sulfosuccinic acid salt is a sulfosuccinic acid dialkali metal salt or a sulfosuccinic acid diammonium salt.
Specific examples of the sulfosuccinic acid alkyl salt used in the present invention include, for example, disodium lauryl sulfosuccinate having a Davis method HLB value of 54 (trade name “Burelite SSS”, manufactured by Sanyo Chemical Industries, Ltd.). .

An anionic surfactant having a Davis method HLB value of less than 45 as used in Comparative Examples 11 and 12, which will be described later, has a poor oil-water separation effect, and the anionic surfactant having a Davis method HLB value of 45 or more. Even if the agent is used, the oil / water separation effect is poor for a mixture of coal tar and water having a moisture content higher than that of coal tar.
By the way, Davis method HLB value of sodium dodecyl sulfate which is a typical anionic surfactant is 40.

The total amount of one or more surfactants selected from the group consisting of a nonionic surfactant having a Griffin method HLB value of 6.5 or more and an anionic surfactant having a Davis method HLB value of 45 or more is The content is preferably 0.005 to 1% by mass, more preferably 0.01 to 0.1% by mass with respect to the minute.
In addition, when adding this nonionic surfactant mainly, it is preferable that the addition amount is 70 mass% or more in all the surfactants.

The above surfactants may be added as they are, such as disodium polyoxyethylene sulfosuccinate or disodium lauryl sulfosuccinate. However, in consideration of mixing and homogenization with the target hydrous coal tar, It is desirable to dilute and add as a liquid.

The oil / water separation method and the oil / water separation agent of the present invention are used in a process for producing coal tar, and the oil / water separation agent may be added at a location where there is more coal tar than moisture, It is preferable to add water to water-containing coal tar containing 0.7 parts by weight or less, especially for coal tar separated by tar decanter, suitable as a method for promoting dehydration in super decanter (centrifuge) ing.

Since coal tar retains moisture as a W / O type emulsion, it is necessary to break the emulsion in order to separate coal tar and water. In the present invention, when a specific surfactant that is an oil-water separator is added, it acts on the interface forming the emulsion and makes it impossible to maintain the emulsion, so water is combined and separated into water and tar. It is done.
A nonionic surfactant having a Griffin method HLB value of 6.5 or more and an anionic surfactant having a Davis method HLB value of 45 or more are easily soluble in water, but are difficult to dissolve and diffuse in tar. Therefore, in the case of hydrous coal tar having a water content of 1 or less with respect to tar 1, these surfactants can concentrate on the water present as an emulsion in the tar and its interface. Therefore, the tar at the tar decanter outlet is more than the addition of these surfactants to a place where there is more water than tar, for example, a mixture of tar and aqueous water on the tar decanter inlet side (tar: safe water = 1: 500 or so). It is considered that adding oil to tar with less water after treatment with decanter (tar: water = 1: 0.1 to 1.0) can achieve a high oil-water separation effect with a small amount of added surfactant. It is done.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 10, Comparative Examples 1 to 14
(Tar): Tar at the exit of the tar decanter (water content 16%, tar content: water content = 1: 0.2) was used.
(Addition amount of oil / water separating agent): Various surfactants which are oil / water separating agents were added so that the total amount of the surfactant was 0.020% by mass with respect to the pure tar content. The Davis method HLB value of an anionic surfactant is a calculated value from a drug structure using the Davis formula.
(Test procedure): Coal tar was allowed to stand in a constant temperature bath at 70 ° C. to raise the temperature, 100 g of coal tar was collected in a sample bottle, and 40 g, 144 g and 464 g of hydrous coal tar and pure water to which pure water was not added were added. Hydrous coal tar (a mixture of coal tar and water) was prepared (the tar: water ratios were 1: 0.2, 1: 0.7, 1: 1.9, and 1: 5.7, respectively). A predetermined amount of a surfactant was added to the resulting coal tar and water mixture with a micropipette. The mixture was stirred for 1 minute with a spatula and allowed to stand for 3 hours in a constant temperature bath at 70 ° C. Then, the external appearance was observed visually, the amount of separated water was measured, and the oil-water separation effect was evaluated.
(Evaluation): From the amount of water in the aqueous phase after centrifugation, it was confirmed what percentage of the water present in the tar was separated.
A ... Amount of separated water of 40% or more B ... Amount of separated water of 20% or more and less than 40% C ... Amount of separated water of less than 20% The test results are shown in Table 1.

 

 

In Examples 1 to 10 (a specific surfactant was added to hydrous coal tar containing 1 part by weight of water in a mass ratio of 1 part or less), a remarkable oil-water separation effect was observed. Since the surfactant used here is easily soluble in water and difficult to dissolve and diffuse in tar, it is thought that it was able to concentrate on moisture present as an emulsion in the tar and its interface. However, these surfactants also greatly reduced the oil-water separation effect in the tar / water mixtures of Comparative Examples 1 to 10 having a large water content. The ratio of the surfactant to water was reduced, and the amount of surfactant acting on the water in the emulsion was reduced. Therefore, it is considered that the oil-water separation effect was lowered.

Claims (8)

One or more surfactants selected from the group consisting of a nonionic surfactant having a Griffin method HLB value of 6.5 or more and an anionic surfactant having a Davis method HLB value of 45 or more are added to 1 part of coal tar. An oil-water separation method for hydrous coal tar, wherein oil-water separation is performed by adding water to hydrous coal tar containing 1 part by mass or less. The oil-water separation method according to claim 1, wherein the nonionic surfactant has a Griffin method HLB value of 7 or more. The oil-water separation method according to claim 1 or 2, wherein the anionic surfactant has a Davis method HLB value of 54 or more. The oil-water separation method according to any one of claims 1 to 3, wherein the hydrous coal tar contains water 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 addition amount of the surfactant is 0.005 to 1 mass% with respect to the pure tar content. Oil / water separation for coal tar, comprising one or more surfactants selected from the group consisting of a nonionic surfactant having a Griffin method HLB value of 6.5 or more and an anionic surfactant having a Davis method HLB value of 45 or more Agent. The oil-water separator for coal tar according to claim 6, wherein the Griffin method HLB value of the nonionic surfactant is 7 or more. The oil-water separator for coal tar according to claim 6 or 7, wherein the anionic surfactant has a Davis method HLB value of 54 or more.