JPH0372564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous alkali hydrosulfide solution (hereinafter simply referred to as "alkali hydrosulfide") which extracts and removes dissolved acidic oil by adding a solvent to an aqueous alkali hydrosulfide solution or its production reaction system produced in a petroleum-related factory. It relates to a method for processing or recovering liquids (referred to as "liquids").

Alkali-soluble acidic oil coexists in cracked gas, fuel gas, waste gas, naphtha, kerosene, etc. in petroleum-related factories, and alkaline liquid cleaning for the purpose of desulfurization, deoxidation, refining, etc. dissolve in Therefore, since such alkaline cleaning waste liquid contains a large amount of acidic oil dissolved therein, it is difficult not only to utilize it, but also to treat pollution, and it is generally treated by neutralization. However, this method not only requires a large amount of chemical solution for neutralization, but also generates acidic gases such as H ₂ S during the neutralization process, and also generates bad odors caused by mercaptans, making it difficult to treat such pollution. Secondary and tertiary treatment is essential, and those involved are struggling because the treatment process is complex and requires a large amount of expense.

Under these circumstances, it is known to those concerned that the numerous technologies developed by the present inventors for producing alkaline hydrosulfide liquid from alkaline waste liquid and H ₂ S-containing gas have been put into practical use and are proving effective. This is something I am passionate about. (Patent No. 401527, Patent No. 404799,
(See No. 417114, No. 418472, No. 800401, No. 900772) However, the alkali hydrosulfide solution produced by these methods contains trace amounts of dissolved acidic oil that is separated and removed in the production process. (solubility limit) is prevented from floating. In this way, the composition of the trace amount of acidic oil dissolved in the alkali hydrosulfide solution varies depending on the alkaline waste liquid that produces the alkali hydrosulfide solution and the _H2S -containing gas, but phenols, thiophenols, mercaptans, etc. It contains one or more species and is a cause of bad odor.

Therefore, the present inventors have developed a method for dealing with the bad odor of alkaline hydrosulfide liquid that has a trace amount of acidic oil dissolved in it, and a treatment method for the odor. We have developed a method for removing malodorous acidic oil using a mixture of oils and oils, and it has been found to be effective. (See Patent No. 638775) However, although mercaptans can be easily removed with this method, acidic oils such as phenols and thiophenols, which have a relatively high solubility in water, or are highly acidic, still remain hydrosulfurized. May remain in alkaline solution. Such an alkaline hydrosulfide solution still has a slight odor due to acidic oil. If this method were to be used to almost completely remove phenols and thiophenols from the alkali hydrosulfide solution, extremely large amounts of extracted fractions such as petroleum fractions and their refined fractions (several tens of liters of the alkali hydrosulfide solution) would be removed. Furthermore, when these fractions and activated carbon are used together for treatment, the effect of removing acidic oil is improved, but the activated carbon adsorbs a large amount of these fractions, making the regeneration process complicated. , increasing regeneration costs.

The alkali hydrosulfide solution that dissolves in trace amounts of acidic oil is concentrated and manufactured into products (alkali hydrosulfide solution containing approx.
70wt%), the acidic oil content moves into the evaporation drain during the concentration process, and even after removing dissolved H ₂ S, COD still remains.
Because of the high level of condensate, pollution treatment using NaClO, oxygen, etc. is essential, and not only does this pollution treatment require a large amount of chemicals, but it also significantly complicates the treatment and operation steps.

Under these circumstances, the present inventors searched for extraction solvents that can effectively remove phenols and thiophenols from alkaline hydrosulfide solution, and as a result of various experimental studies, we found that ketones, alcohols, and It has been discovered that a solvent consisting of one or more of ether-based and ester-based solvents has a remarkable effect in removing acidic oil components compared to petroleum fractions and refined fractions thereof. We have also discovered that by adding one or more of these solvents to the reaction system for producing alkaline hydrosulfide, it is possible to recover alkaline hydrosulfide with almost no acidic oil dissolved therein.

That is, the present inventors added alcohol such as isobutyl methyl ketone, butyl methyl ketone, methyl propyl ketone, etc. to the alkaline hydrosulfide solution or its production reaction system as a ketone solvent that is sparingly soluble or insoluble in water and stable to alkali. 2- as a solvent
Ethylhexanol, n-octanol, n-heptanol, etc., ether solvents such as diptyl ether, isopropyl ether, ester solvents such as n-butyl acetate, and halogenated hydrocarbon solvents such as 1,1,1-trichloroethane. After adding one or more types, acidic oils including mercaptans, phenols, and thiophenols can be removed very easily by dispersing and extracting them in the treatment liquid using an appropriate method such as stirring or shaking. They discovered that it is possible to remove the foul odor caused by acidic oil, and it is also possible to significantly reduce the COD of evaporative condensate that is generated as a result of concentrating the hydrosulfurized alkali solution that is being treated or recovered.

It was also confirmed that when extracting and removing only mercaptans using these solvents, it was possible to sufficiently remove them with approximately 1/5 to 1/50 of the amount used in the case of petroleum fractions and their refined fractions.

Next, the present inventors investigated the treatment or recovery conditions for alkaline hydrosulfide solution using the above-mentioned solvent, and found that the proportion of alkali sulfide is high (the PH of the alkali hydrosulfide solution or its production reaction system is high). ) and the removal effect of acidic oil tends to decrease, but the alkaline sulfide content is 7 mol% relative to the alkaline hydrosulfide content.
Hereinafter, it has been confirmed that if the concentration is preferably 5.5 mol % or less, the alkali hydrosulfide content can be removed effectively at room temperature without affecting the concentration. Note that the amount of extraction solvent added can be estimated based on the desired removal rate if the acidic oil concentration is known; however, if the amount is too small relative to the amount of treated liquid, the contact efficiency will decrease;
Since dispersion operations such as stirring and shaking are required for a long time, it was confirmed that it is preferable to set the amount to at least 2% by volume or more based on the amount of the processing liquid.

It was also confirmed that the solvent used to extract the acidic oil can be easily regenerated with caustic alkaline solution by a conventional method and can be used repeatedly for extracting the acidic oil. In addition, the pH of the caustic alkaline solution for regenerating the used solvent is preferably at least 12 or higher,
It was also confirmed that it was possible to concentrate the acidic oil to an extremely high concentration in the regenerated liquid even if it was only a small amount.

Furthermore, the present inventors have found that when these solvents are used in the hydrosulfide alkali solution or the production reaction system to concentrate the hydrosulfide alkali solution that has been treated or recovered, the COD is still slightly elevated in the condensate. After considering the above, we arrived at the idea that the solvent used in the present invention dissolves in a very small amount in the treated or recovered alkaline hydrosulfide solution, and in order to suppress and prevent the mixing of the solvent into the alkaline hydrosulfide solution,
As a result of various experiments, it was found that the treatment or recovery operation of alkaline hydrosulfide solution was carried out using extraction solvents such as ketone, alcohol, ether, and ester in an amount of 2 to 50% by volume.
The acidic oil content is removed by using a solvent that is more insoluble in water than the above-mentioned extraction solvent (hereinafter, these solvents are referred to as "insoluble solvents"), such as n-hexane, n-heptane, and silicone oil containing It was confirmed that it was possible to suppress or prevent a small amount of solvent from dissolving in the alkaline hydrosulfide solution without sacrificing its effectiveness, and that most of the COD in the evaporative drain could be removed when the alkali hydrosulfide solution was concentrated. Also, ketone type, alcohol type, ether type,
The effect of preventing solvent contamination was also observed by reprocessing the alkaline hydrosulfide solution, which had been treated or recovered using an ester-based solvent, with an insoluble solvent.

That is, the present inventors have discovered that one or more types of ketone-based, alcohol-based, ether-based, and ester-based solvents that are sparingly soluble or insoluble in water from the alkaline hydrosulfide solution produced in petroleum-related factories or the resulting reaction system. Mercaptans, phenols, and thiophenols can be extracted by adding a solvent or a mixed solvent of these solvents and an insoluble solvent and dispersing the mixture in the treatment liquid using an appropriate method such as stirring or shaking. Since it can be almost completely removed, an alkaline hydrosulfide solution without the bad odor caused by acidic oil can be obtained, and the COD of evaporation condensate generated during the concentration process can be reduced.
It was confirmed that most of the

As explained above, the present invention uses a ketone type, alcohol type, ether type, which is sparingly soluble or insoluble in water, as an extraction solvent for acidic oil in a hydrosulfurized alkali liquid generated in a petroleum-related factory or its production reaction system.
By adding a solvent consisting of one or more types of ester solvents, or a mixed solvent of these solvents and other insoluble solvents, it is possible to remove substances that are difficult to remove with conventional petroleum fractions or their refined fractions. This is an economical method for treating or recovering an alkali hydrosulfide solution, which makes it possible to easily remove acidic oil containing phenols and thiophenols.

Next, in order to make the method of the present invention more clear, the method will be specifically explained using examples.

Example 1 NaSH liquid 1, which was produced in an oil refinery and has the composition and properties shown in Table 1, was stirred with 80 ml of isobutyl methyl ketone, a ketone solvent, as an extraction solvent for removing acidic oil from the NaSH liquid. After the mixture was placed in a flask (No. 2) equipped with an equipment and stirred for 5 minutes, the solvent was separated by a standing method to obtain a treatment liquid containing almost no acidic oil as shown in Table 2.

This treatment liquid also removes the bad odor caused by acidic oil, and also removes the odor caused by the condensation process.
COD was rare.

Furthermore, the isobutyl methyl ketone used here, regenerated using a conventional caustic alkaline solution, could be used repeatedly for extraction of acidic oils.

Table 1 Composition and properties of NaSH liquid NaSH 26.80wt% Na ₂ S 2.01 〃 Na ₂ CO ₃ 1.00 〃 Na ₂ SO ₃ 0.65 〃 Na ₂ S ₂ O ₃ 0.20 〃 Acidic oil content 450ppm Drain COD (Note) 1060 〃 Na ₂ S/NaSH (5.39 mol%) Table 2 Composition and properties of treatment liquid NaSH 26.79wt% Na ₂ S 2.02 〃 Na ₂ CO ₃ 0.99 〃 Na ₂ SO ₃ 0.65 〃 Na ₂ S ₂ O ₃ 0.20 〃 Acidic oil content 3ppm Drain COD 38 〃 (Note) Dissolved H ₂ S is removed from the evaporation drain generated when NaSH solution is concentrated to 70wt%.

Example 2 A NaSH solution produced in a petrochemical factory and having the composition and properties shown in Table 3 was treated in the same equipment as in Example 1 with NaSH solution 1 and alcoholic solvent 2-2 as an extraction solvent for acidic oil. By adding 60 ml of ethylhexanol and carrying out the same operations and methods as in Example 1, a treatment solution containing almost no acidic oil as shown in Table 4 was obtained.

As with the previous example, this treated solution was able to remove bad odors, and the COD of the drain due to concentration was also low.

Table 3 Composition and properties of NaSH liquid NaSH 22.30wt% Na ₂ S 1.32 〃 Na ₂ CO ₃ 1.40 〃 Na ₂ SO ₃ 0.46 〃 Na ₂ S ₂ O ₃ 0.12 〃 Acidic oil content 96ppm Na ₂ S/NaSH (4.25 mol%) Table 4 Composition and properties of treatment liquid NaSH 22.31wt% Na ₂ S 1.32 〃 Na ₂ CO ₃ 1.40 〃 Na ₂ SO ₃ 0.43 〃 Na ₂ S ₂ O ₃ 0.11 〃 Acidic oil 1ppm Example 3 Produced at an oil refinery NaSH liquid having the composition and properties shown in Table 5 was treated using the same equipment and method as in Example 1, using NaSH liquid 1 and dibutyl ether, an ether solvent, as an extraction solvent for acidic oil.
Using 130 ml, a treatment solution containing almost no acidic oil as shown in Table 6 was obtained.

Similar to Examples 1 and 2, this treatment solution was able to remove bad odors, and the COD of the drain due to concentration was also low.

Table 5 Composition and properties of NaSH liquid NaSH 25.59wt% Na ₂ S 1.18 〃 Na ₂ CO ₃ 0.92 〃 Na ₂ SO ₃ 0.53 〃 Na ₂ S ₂ O ₃ 0.32 〃 Acidic oil content 295ppm Na ₂ S/NaSH (3.31 mol%) Table 6 Composition and properties of treatment liquid NaSH 25.60wt% Na ₂ S 1.19 〃 Na ₂ CO ₃ 0.90 〃 Na ₂ SO ₃ 0.53 〃 Na ₂ S ₂ O ₃ 0.30 〃 Acidic oil 2ppm Example 4 Composition used in Example 2 , NaSH liquid 1 with properties was treated using the same equipment and method as in Example 1, using the ester solvent n-butyl acetate 60 as the acidic oil extraction solvent.
ml, a treatment solution equivalent to that of Example 2 was obtained, and the same effects as Example 1 were observed.

Example 5 NaSH liquid 1 having the composition and properties used in Example 3 was treated using the same equipment and method as in Example 1, using 40 ml of isobutyl methyl ketone and 2-
A treatment solution equivalent to that in Example 3 was obtained by using a solvent mixed with 40 ml of ethylhexanol, and the same effects as in Example 1 were observed.

Example 6 NaSH liquid 1 having the composition and properties used in Example 1 was treated using the same equipment and method as in Example 1 using a mixed solvent of 80 ml of isobutyl methyl ketone as an extraction solvent for acidic oil and 150 ml of n-hexane as an insoluble solvent. A processing solution containing almost no acidic oil as shown in Table 7 was obtained.

This treatment liquid can also remove bad odors in the same manner as in Examples 1 to 5, and the effect of n-hexane can also remove drains.
COD was significantly reduced.

Table 7 Composition and properties of NaSH liquid NaSH 26.79wt% Na ₂ S 2.00 〃 Na ₂ CO ₃ 1.02 〃 Na ₂ SO ₃ 0.67 〃 Na ₂ S ₂ O ₃ 0.20 〃 Acidic oil content 3ppm COD of drain 6 〃 Example 7 Example NaSH liquid 1 having the composition and properties used in Example 1 was treated using the same equipment and method as in Example 1, using 80 ml of isobutyl methyl ketone and 150 ml of n-hexane for the 15th regeneration with caustic alkaline solution as the extraction solvent for acidic oil.
A treatment solution equivalent to that in Example 6 was obtained by using a mixed solvent with ml and the same as in Examples 1 to 6, and the bad odor was also removed.

Example 8 0.85% alkaline waste liquid discharged from an oil refinery and having the composition and properties shown in Table 8, 200 ml of isobutyl methyl ketone as an extraction solvent for acidic oil, and 350 ml of n-hexane as an insoluble solvent were mixed with a stirring device,
2 equipped with a gas inlet and an outlet for unreacted gas.
Place the H ₂ S gas into a three-necked flask and add Na ₂ S gas from the gas inlet while operating the stirrer.
After absorbing NaSH to a concentration of about 2 mol % based on the NaSH content to generate a NaSH liquid, the solvent is separated by a standing method to produce a NaSH liquid containing almost no acidic oil as shown in Table 9. Recovered.

It should be noted that this recovered liquid was also able to remove the bad odor caused by the acidic oil content, and the COD in the drain obtained by concentrating the recovered liquid was also low.

Table 8 Composition and properties of alkaline waste liquid NaOH 15.90wt% Na ₂ S 5.60 Acidic oil 6400ppm Table 9 Composition and properties of recovered liquid NaSH 25.20wt% Na ₂ S 0.73 〃 Na ₂ CO ₃ 0.89 〃 Na ₂ SO ₃ 0.12 〃 Na ₂ S ₂ O ₃ 0.08 〃 Acidic oil content 3 ppm COD of drain 6 〃 Na ₂ S/NaSH (2.08 mol%) Example 9 In Example 8, only 220 ml of isobutyl methyl ketone was used as the extraction solvent, and the rest were as in Example 8. When carried out in the same manner, the result was as shown in Table 10.
The NaSH solution was collected.

Table 10 Composition and properties of recovered liquid NaSH 25.07wt% Na ₂ S 0.82 〃 Na ₂ CO ₃ 0.89 〃 Na ₂ SO ₃ 0.10 〃 Na ₂ S ₂ O ₃ 0.07 〃 Acidic oil content 3ppm COD of drain 35 〃 Na ₂ S/NaSH (2.35 mol%) These examples are only examples for specifically explaining the present invention, and of course include many elements of modification and improvement within the limits, and do not constrain the technical idea of the present invention. It's not something you do.

As explained above, the present invention provides one or two types of ketone-based, alcohol-based, ether-based, and ester-based solvents that are sparingly soluble or insoluble in water to the alkaline hydrosulfide solution produced in petroleum-related factories or the production reaction system thereof. This is a method for treating or recovering an alkali hydrosulfide solution, which is characterized by adding a solvent consisting of more than 1 species, or a mixed solvent of these solvents and other insoluble solvents to extract and remove acidic oil components.

By implementing the method of the present invention, the following effects can be expected.

A high-grade alkaline hydrosulfide solution containing almost no dissolved acidic oil can be obtained, and the quality of the concentrated product is significantly improved.

Since it is possible to obtain an alkaline hydrosulfide solution that does not have a bad odor due to acidic oil, it is possible to prevent environmental pollution due to bad odor, which is useful for preventing pollution, and its social effects are significant.

During the concentration process of alkaline hydrosulfide solution, the COD of the evaporative condensate generated is significantly reduced.
It not only simplifies the pollution equipment required for drain treatment but also significantly reduces operating costs, which has great social and economic effects.

Conventional pollution treatment equipment can be reused and no special treatment equipment is required, further increasing the economic effect.

Claims (1)

[Claims] 1. Adding one or more types of ketone, alcohol, ether, and ester solvents that are poorly soluble or insoluble in water to the aqueous alkali hydrosulfide solution or reaction system for producing aqueous alkali hydrosulfide solutions produced in petroleum-related factories. Solvents or these solvents,
Furthermore, by adding a mixed solvent with a water-insoluble solvent and dispersing it in the treated aqueous solution, a trace amount of acidic oil dissolved in the alkali hydrosulfide aqueous solution is extracted and removed. Treatment or recovery method.