KR20150139506A - Method for removing sulfur-containing compound - Google Patents

Abstract

The method for removing a sulfur-containing compound according to the present invention includes a step of bringing a crude hydrocarbon containing at least one sulfur-containing compound selected from the group consisting of carbon disulfide and mercaptans into contact with an amide compound and a nitrite salt .

Description

[0001] METHOD FOR REMOVING SULFUR-CONTAINING COMPOUND [0002]

The present invention relates to a method for removing sulfur-containing compounds, and more particularly, to a method for removing sulfur-containing compounds by removing carbon disulfide and mercaptans contained in hydrocarbons, And a method for removing the compound.

In recent years, various hydrocarbon fractions, which are produced as a by-product in the process of decomposing naphtha and the like to produce ethylene and the like, may be accompanied by a large amount of components derived from a sulfur compound contained in the raw material as compared with the prior art. Among them, the C5 oil fraction mainly composed of hydrocarbons having 5 carbon atoms is accompanied by sulfur-containing compounds such as carbon disulfide, mercaptans and dimethyl sulfide having a boiling point close to that of C5 oil. Particularly, There is a case. When the content of the sulfur-containing compound is large, sulfur-containing compounds are incorporated into isoprene, piperylene, dicyclopentadiene and the like obtained by refining from C5 oil, and when they are used as raw materials, rubber and resin are inhibited Or the odor of the product is generated, it is necessary to remove the sulfur-containing compound.

Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2005-281602) discloses a method for removing carbon disulfide by bringing a hydrocarbon containing carbon disulfide into contact with a polyvalent amine and alkaline water.

Japanese Patent Application Laid-Open No. 2005-281602

However, in the method disclosed in Patent Document 1, when the application to an industrial process is considered, the facility cost for wastewater treatment is increased, and therefore, a new improvement is demanded. Further, it was insufficient to remove the mercaptans contained in the hydrocarbons.

SUMMARY OF THE INVENTION The present invention has been made in view of the prior art as described above, and it is an object of the present invention to provide a method capable of easily and efficiently removing a sulfur-containing compound, in particular carbon disulfide and mercaptane from a hydrocarbon containing a sulfur- .

As a result of intensive studies to solve the above problems, the present inventors have found that it is possible to easily remove carbon disulfide and mercaptans by bringing a hydrocarbon containing carbon disulfide and mercaptane into contact with an amide compound and a nitrite salt The present invention has been completed based on these findings.

The gist of the present invention is as follows.

(A) a step of bringing a crude hydrocarbon containing at least one sulfur-containing compound selected from the group consisting of carbon disulfide and mercaptans into contact with an amide compound and a nitrite.

(B) A process for producing purified hydrocarbons comprising a method for removing the sulfur-containing compound according to (A).

According to the method for removing a sulfur-containing compound of the present invention, it is possible to easily and efficiently remove sulfur-containing compounds, particularly carbon disulfide and mercaptans, contained in hydrocarbons, Improvement is possible.

Fig. 1 shows a schematic configuration of an apparatus used in the present invention.

Hereinafter, the present invention will be described in more detail. The method for removing a sulfur-containing compound of the present invention includes a step of bringing a prepared hydrocarbon containing at least one sulfur-containing compound selected from the group consisting of carbon disulfide and mercaptans into contact with an amide compound and a nitrite.

The crude hydrocarbons generally contain various sulfur-containing compounds in hydrocarbons. Among the sulfur-containing compounds, in the present invention, carbon disulfide and mercaptans are to be removed.

The crude hydrocarbon is not particularly limited, but it is preferably C4 oil fraction containing a hydrocarbon having 4 carbon atoms as a main component or C5 oil fraction containing a hydrocarbon having 5 carbon atoms as a main component. These prepared hydrocarbons are, for example, oil fractions produced as a by-product in the process of decomposing naphtha to produce ethylene and the like.

Among them, the method of the present invention is particularly effective for a crude hydrocarbon containing C5 oil as a main component, the boiling point of which is close to that of carbon disulfide and mercaptans and is difficult to separate from carbon disulfide and mercaptans.

Examples of the hydrocarbon having 4 carbon atoms contained in the C4 fraction include 1,3-butadiene, n-butane, isobutane, 1-butene, 2-butene, isobutene and vinyl acetylene. On the other hand, examples of the hydrocarbon having 5 carbon atoms contained in the C5 oil include isoprene, isoamylene, amylene, n-pentane, isopentane, piperylene, cyclopentane, cyclopentene and cyclopentadiene. .

Examples of mercaptans which are one kind of sulfur-containing compounds include chain mercaptans, cyclic mercaptans and the like. The number of carbon atoms of the mercaptans is preferably 20 or less, more preferably 1 to 15, and still more preferably 1 to 10.

Examples of such chain type mercaptans include methyl mercaptan, ethyl mercaptan, normal propyl mercaptan, isopropyl mercaptan and the like. Examples of the cyclic mercaptans include cyclopentyl mercaptan, cyclohexyl mercaptan, 2 -Methylcyclopentylmercaptan, 3-methylcyclopentylmercaptan and the like. Among them, ethylmercaptan is particularly preferable as a sulfur-containing compound to be treated by the removal method of the present invention because its boiling point is particularly close to isoprene which is one of the objects to be subjected to distillation purification. The mercaptans may be contained in the prepared hydrocarbons in one kind or in two or more kinds.

The crude hydrocarbon to be treated according to the present invention is not particularly limited as long as it is a hydrocarbon containing carbon disulfide and / or mercaptan, and preferably contains carbon disulfide and mercaptans in an amount of 10,000 ppm or less, more preferably 1,000 ppm or less, ppm or less, particularly preferably 500 ppm or less. Also, carbon disulfide and mercaptans are contained in a total amount of preferably 1 ppm or more. When the total amount of carbon disulfide and mercaptans is in the above range, the sulfur-containing compound can be efficiently removed.

Examples of the amide compound used in the present invention include a chain amide compound and a cyclic amide compound. The carbon number of the amide compound is preferably 20 or less, more preferably 3 to 15, still more preferably 3 to 10.

Examples of the chained amide compound include N, N-dimethylformamide, N-methyl-N-phenylformamide, N, N-diphenylformamide, N, N-dimethylacetamide, Amide, N, N-diphenylacetamide, N, N-diethylformamide, N-ethyl-N-phenylformamide, N, N-diethylacetamide, , And examples of the cyclic amide compound include N-methylpyrrolidone, N-ethylpyrrolidone, N-methylpiperidone, N-ethylpiperidone and the like. Of these, a chained amide compound is preferred, and from the viewpoint of operability, a chain amide compound which is liquid at 50 占 폚 1 atm is more preferable, and N, N-dimethylformamide is more preferable. The amide compounds may be used alone or in combination of two or more.

Examples of the nitrite used in the present invention include alkali metal nitrite, alkaline earth metal nitrite and the like. Specific examples of the alkali metal nitrite include sodium nitrite, potassium nitrite, and specific examples of the alkaline earth metal nitrite include magnesium nitrite, calcium nitrite, and the like. Of these, from the viewpoint of solubility, alkali metal nitrite is preferable, sodium nitrite and potassium nitrite are more preferable, and sodium nitrite is particularly preferable.

The nitrite may be used in a salt state, but in the case of mixing with an amide compound from the viewpoint of solubility, it may be dissolved in water and used as an aqueous solution. By dissolving the nitrite in water and then mixing it with the amide compound, it is easily dissolved in the amide compound. In the case of an aqueous solution, there is no particular limitation on the concentration of nitrite when it is dissolved in water, but it is preferably 50% by weight or less, particularly preferably 20% by weight or less.

In the present invention, the method of contacting the prepared hydrocarbon containing carbon disulfide and mercaptans with the amide compound and the nitrite is not particularly limited. However, it is preferable to use (a) a hydrocarbon having anhydrous carbon and a mercaptan, an amide compound and a nitrite (B) a method in which a nitrite salt is mixed with an amide compound, followed by bringing a prepared hydrocarbon containing carbon disulfide and mercaptans into contact with each other. However, in view of the removal performance of carbon disulfide and mercaptans , The method (b) is preferable. In addition, both of the methods (a) and (b) may be either a continuous type or a batch type.

The amount ratio of the amide compound and the prepared hydrocarbon in the contacting step (hereinafter, sometimes referred to simply as "contacting step") is not particularly limited, but is preferably 0.1 to 1 part by weight (amide compound / crude hydrocarbon) 100/1, more preferably 0.5 / 1 to 50/1, particularly preferably 1/1 to 10/1. When the amount ratio of the amide compound and the prepared hydrocarbon is within the above range, the sulfur-containing compound can be sufficiently removed.

The amount of nitrite to be used in the contacting step is not particularly limited, but is preferably 0.01 to 1,000 ppm, more preferably 0.1 to 100 ppm, particularly preferably 0.5 to 50 ppm in the amide compound. When the addition amount of the nitrite is within the above range, the nitrite can be sufficiently dissolved in the amide compound, and the sulfur-containing compound can be efficiently removed.

The amount ratio of nitrite and carbon disulfide is not particularly limited, but is preferably 0.01 / 1 to 100/1, more preferably 0.02 / 1 to 50/1, (Nitrite / mercaptans), preferably 0.1 / 1 to 100/1, and more preferably 0.2 / 1, in terms of the molar ratio (nitrite / mercaptan), although the amount ratio of nitrite and mercaptan is not particularly limited. To 50/1, and particularly preferably from 0.3 / 1 to 30/1. When the addition amount of the nitrite is within the above range, the sulfur-containing compound can be sufficiently removed.

The temperature in the contacting step is not particularly limited, but is preferably 0 to 250 占 폚, more preferably 10 to 200 占 폚. When the temperature at the time of contact is too low, the sulfur-containing compound can not be sufficiently removed. When the temperature is too low, unsaturated hydrocarbons in the prepared hydrocarbon cause polymerization reaction or the like, resulting in generation of a high molecular weight compound and a decrease in product yield have. For example, when the prepared hydrocarbon contains isoprene, if the temperature at the time of contact is excessively high, a dimer of isoprene or the like is produced, and the yield of isoprene is lowered in some cases.

The contacting step may be carried out at normal pressure or under pressure of about 0 to 3 MPa. The contact time is not particularly limited, but is preferably 1 second to 300 minutes, and more preferably 1 minute to 180 minutes.

The reason why carbon disulfide and mercaptans in the prepared hydrocarbon are removed by contact with the amide compound and nitrite is not theoretically bound at all, but the following can be conceived. That is, in the contacting step, carbon disulfide and mercaptans react with an amide compound and a nitrite to form a low-boiling-point sulfur-containing compound or a high boiling-point sulfur-containing compound. As a result, the low-boiling-point sulfur-containing compound is volatilized and the high boiling-point sulfur-containing compound becomes a liquid or a salt and is separated as a residual component or the like through a distillation operation or the like, It is conceivable that carbon disulfide and mercaptans in the prepared hydrocarbons are removed.

Fig. 1 shows a preferred embodiment of the method for removing carbon disulfide and mercaptans of the present invention, but the present invention is not limited to this embodiment. 1, a mixture of an amide compound and a nitrite aqueous solution is supplied from a pipe 1 above a side surface of the contact container 3 to a carbon dioxide disulfide and a crude hydrocarbon containing mercaptans from a pipe 2 below the side wall And the hydrocarbon oil fractions are separated from the amide compound and the nitrite by distillation and purified hydrocarbons having reduced sulfur content from the top pipe 4 of the contact vessel 3 are introduced into the contact vessel 3, . The separation conditions are not particularly limited, but in the case of separating the C5 oil, purified hydrocarbons are obtained from the top pipe 4 by a distillation step in which the liquid temperature is maintained at about 120 to 160 DEG C after the contacting step.

As the contact container, it is preferable to use a pressure-resistant container having an agitator and a circulating device. After the contact process is performed in the pressure-resistant container, the pressure is released to obtain a purified hydrocarbon having a reduced content of carbon disulfide and mercaptans from the top pipe (4).

Since the effluent from the bottom pipe 5 of the vessel 3 contains unreacted amide compounds, nitrite salts and various additives, they may be recovered and reused.

In the embodiment of Fig. 1, when carbon disulfide or mercaptans are removed, in order to suppress the contamination of the contact container 3, the amide compound may be added with furfural, methylfurfural, Heterocyclic polar compounds such as carboaldehyde, nicotine aldehyde, and pyridoxal; Aromatic nitro compounds such as nitrobenzene, nitrotoluene, nitroxylene, nitromeshtyylene, dinitrobenzene, and trinitroxylene; Aromatic aldehydes such as benzaldehyde, tolualdehyde, cumin aldehyde, phenylacetaldehyde, cinnamaldehyde, phthalaldehyde, isophthalaldehyde and terephthalaldehyde; Or the like may be added. Of these, furfural, nitrobenzene and benzaldehyde are preferable, and furfural is particularly preferable.

The amount of these additives to be added is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 15 parts by weight, based on 100 parts by weight of the amide compound.

The total content of carbon disulfide and mercaptans contained in the purified hydrocarbon obtained by bringing the crude hydrocarbon into contact with the amide compound and the nitrite and thereafter separating the same from the amide compound and the nitrite and recovering the same is reduced, ppm or less, more preferably 100 ppm or less, particularly preferably 50 ppm or less, and is further reduced to a value lower than the total content of carbon disulfide and mercaptans in the prepared hydrocarbons.

As described above, the method for removing the sulfur-containing compound according to the present invention is preferably a C4 oil fraction mainly composed of hydrocarbons having 4 carbon atoms or a C5 oil fraction mainly composed of hydrocarbons having 5 carbon atoms.

The method of removing the sulfur-containing compound according to the present invention is preferably a method of separating the crude hydrocarbon from the amide compound and the nitrite after the step of bringing the crude hydrocarbon into contact with the amide compound and the nitrite, And a distillation step of recovering the solvent.

In the method for removing a sulfur-containing compound according to the present invention, preferably, the sulfur-containing compound content in the prepared hydrocarbon is 1 ppm or more and 10,000 ppm or less, the sulfur-containing compound content in the purified hydrocarbon is 300 ppm or less, Containing compounds in the hydrocarbons.

The method for producing purified hydrocarbons according to the present invention preferably includes a method for removing the sulfur-containing compound.

Example

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. "Parts", "%", and "ppm" in the examples and comparative examples are on a mass basis unless otherwise specified. The content of the sulfur-containing compound in the prepared hydrocarbon and the purified hydrocarbon was measured by the following apparatuses and conditions.

device GC7890 manufactured by Agilent

column DB-1 Length 30 m, inner diameter 0.32 mm, film thickness 0.25 m

Column temperature Kept at 40 DEG C for 10 minutes, then heated to 10 DEG C per minute, maintained at 250 DEG C for 3 minutes

Inlet temperature 140 ° C

Carrier gas Helium (minute flow rate 1.17 ml)

Detector Agilent 355 Chemiluminescent Sulfur Detector (SCD)

≪ Example 1 >

(Composition: C4 (hydrocarbon having 4 carbon atoms), 22.0% of n-pentane, 20.1% of isopentane) containing 13.3 ppm of carbon disulfide and 2.0 ppm of ethyl mercaptan was added to a stainless steel pressure- , Cyclopentene 2.5%, cyclopentadiene 6.6%, C6 (having 6 carbon atoms), cyclopentadiene 6%, cyclopentadiene 6.6%, cyclopentadiene 6.6%, aminolene 6.9%, isoamylene 7.4%, 1,4-pentadiene 1.5%, isoprene 15.6%, piperylene 10.6% , 3.6%), 323.6 parts of a solution containing 97.4% of dimethylformamide, 2.6% of furfural and 0.7% of sodium nitrite was injected. The mixed solution of the two solutions was heated to 120 DEG C while being stirred and maintained for 1 hour. Then, the gaseous C5 oil fraction was discharged from the upper part of the vessel while maintaining the liquid temperature at 120 to 160 DEG C, 67.6 parts of purified C5 oil containing 1.3 ppm of ethyl mercaptan was obtained. In the container, 309.3 parts of a solution containing neither carbon disulfide nor ethyl mercaptan remained. As a result, 27.8% of the carbon disulfide contained in the crude C5 oil fraction and 36.3% of ethyl mercaptan were removed.

≪ Comparative Example 1 &

(Composition: C4 (hydrocarbon having 4 carbon atoms), 22.0% of n-pentane, 20.1% of isopentane) containing 26.9 ppm of carbon disulfide and 1.8 ppm of ethyl mercaptan was added to a stainless steel pressure- , Cyclopentene 2.5%, cyclopentadiene 6.6%, C6 (having 6 carbon atoms), cyclopentadiene 6%, cyclopentadiene 6.6%, cyclopentadiene 6.6%, aminolene 6.9%, isoamylene 7.4%, 1,4-pentadiene 1.5%, isoprene 15.6%, piperylene 10.6% Of hydrocarbons) 3.6%), 303.3 parts of a solution containing 97.4% of dimethylformamide and 2.6% of furfural and no sodium nitrite was injected. The mixed solution of the two solutions was heated to 120 DEG C while being stirred and maintained for 1 hour. Then, the gas phase C5 fraction was extracted from the upper portion of the vessel while maintaining the liquid temperature at 120 DEG C to 160 DEG C, resulting in 27.1 ppm of carbon disulfide, 63.9 parts of C5 fraction containing 1.8 ppm of ethyl mercaptan was obtained. Further, 288.6 parts of a solution containing neither carbon disulfide nor ethyl mercaptan remained in the container. As a result, the disulfide carbon contained in the crude C5 oil was not removed and the ethylmercaptan was also removed by only 0.8%.

≪ Example 2 >

8.6 parts of a crude C5 oil solution (composition: 94.1% of isoprene, 2.8% of 2-butyne) containing 149.6 ppm of carbon disulfide and 13.4 ppm of ethyl mercaptan was added to a stainless steel pressure vessel equipped with a stirrer, 46.4 parts of a solution containing 3.9% of furfural and 8.9 ppm of sodium nitrite was injected. The mixed solution was heated to 120 DEG C with stirring and maintained for 1 hour. While keeping the liquid temperature at 120 DEG C to 160 DEG C, the gaseous C5 oil fraction was discharged from the upper part of the vessel. As a result, 19.2 ppm of carbon disulfide, To obtain 8.6 parts of purified C5 oil containing 9.1 ppm. In the container, 42.1 parts of a solution containing neither carbon disulfide nor ethyl mercaptan remained. As a result, 87.2% of the carbon disulfide contained in the crude C5 oil and 32.1% of ethyl mercaptan were removed.

≪ Example 3 >

9.6 parts of a crude C5 oil solution (composition: 94.1% of isoprene, 2.8% of 2-butene) containing 34.0 ppm of carbon disulfide and 9.0 ppm of ethyl mercaptan was added to a stainless steel pressure-resistant container to which an agitator was attached, 51.8 parts of a solution containing 3.9% of furfural and 3.3 ppm of sodium nitrite was injected. The mixed solution of the two solutions was heated to 120 ° C while being stirred and maintained for 1 hour. Then, the gaseous C 5 fraction was extracted from the upper part of the vessel while maintaining the liquid temperature at 120 ° C to 160 ° C. As a result, 9.6 parts of purified C5 oil containing 5.7 ppm of ethyl mercaptan was obtained. In the vessel, 45.2 parts of a solution containing neither carbon disulfide nor ethyl mercaptan remained. As a result, 75.6% of the carbon disulfide contained in the crude C5 oil fraction and 36.7% of ethyl mercaptan were removed.

The above results are summarized in the table below.

1: Side upper piping
2: side lower piping
3: Contact container (pressure vessel)
4: Top piping
5: Bottom piping

Claims (7)

(Crude) hydrocarbon containing at least one sulfur-containing compound selected from the group consisting of carbon disulfide and mercaptans with an amide compound and a nitrite. The method according to claim 1,
Wherein the prepared hydrocarbon is a C4 oil fraction containing a hydrocarbon having 4 carbon atoms as a main component or a C5 oil fraction containing a hydrocarbon having 5 carbon atoms as a main component. The method according to claim 1,
Further comprising a step of separating the crude hydrocarbon from the amide compound and the nitrite after the step of bringing the crude hydrocarbon into contact with the amide compound and the nitrite, and further a distillation step of recovering the purified hydrocarbon having the reduced content of the sulfur-containing compound. 3. The method of claim 2,
Further comprising a step of separating the crude hydrocarbon from the amide compound and the nitrite after the step of bringing the crude hydrocarbon into contact with the amide compound and the nitrite, and further a distillation step of recovering the purified hydrocarbon having the reduced content of the sulfur-containing compound. The method of claim 3,
Wherein the content of the sulfur-containing compound in the prepared hydrocarbon is 1 ppm or more and 10,000 ppm or less, and the content of the sulfur-containing compound in the purified hydrocarbon is 300 ppm or less and lower than the content of the sulfur-containing compound in the hydrocarbon-containing hydrocarbon. 5. The method of claim 4,
Wherein the content of the sulfur-containing compound in the prepared hydrocarbon is 1 ppm or more and 10,000 ppm or less, and the content of the sulfur-containing compound in the purified hydrocarbon is 300 ppm or less and lower than the content of the sulfur-containing compound in the hydrocarbon-containing hydrocarbon. A process for the production of refined hydrocarbons comprising the removal of the sulfur-containing compound according to any one of claims 3 to 6.

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