KR20210156002A - Manufacturing method of insoluble sulfur - Google Patents

Abstract

The present invention relates to a method for preparing insoluble sulfur which can provide insoluble sulfur having excellent thermal stability and higher purity as compared to the commercially available products by carrying out an additional step of adding a sulfide to liquid sulfur before a step of heating sulfur to vaporize the same. The method for preparing insoluble sulfur includes a step of adding at least one sulfide selected from the group consisting of ethyl disulfide, methyl disulfide, propyl disulfide, diethyl disulfide, dimethyl disulfide and dipropyl disulfide to liquid sulfur, followed by mixing, to prepare an organic sulfur compound.

Description

Manufacturing method of insoluble sulfur {MANUFACTURING METHOD OF INSOLUBLE SULFUR}

The present disclosure relates to a method for producing insoluble sulfur, and to a method for producing insoluble sulfur with improved thermal stability by additionally adding sulfide to liquid sulfur before heating and vaporizing sulfur.

Unless otherwise indicated herein, the material described in this section is not prior art to the claims of this application, and inclusion in this section is not an admission that it is prior art.

In general, sulfur includes soluble sulfur that dissolves in carbon disulfide and insoluble sulfur that does not dissolve in carbon disulfide because the atoms have a regular arrangement with a certain relationship and have crystalline properties. Since this insoluble sulfur can crosslink rubber and related materials, it is mainly used as a crosslinking agent in the manufacture of rubber products.

On the other hand, domestic refineries have been producing desulfurized oil since the early 1995s, and as a result, more than 3,000 tons of general soluble sulfur are currently being produced in Korea every day, but in the case of insoluble sulfur, despite attempts to manufacture it several times, Due to the low stability problem, domestic production is difficult, and the entire amount is dependent on imports.

As a method for improving such a problem, Patent Document 1 discloses a manufacturing process of insoluble sulfur in which hydrogen sulfide in about 5% by weight based on the total weight of sulfur is directly injected into a sulfur steam heating furnace to which molten sulfur or sulfur is supplied. In Patent Document 2, (a) heating and cooling carbon disulfide, molten sulfur, and sulfur polymer, (b) extracting the suspension from the cooling vessel, (c) cooling a part of the suspension A procedure for the production of insoluble sulfur comprising recycling to a vessel for

The above-mentioned Patent Document 1 discloses that hydrogen sulfide is injected into the part where sulfur is evaporated or injected into molten sulfur, but hydrogen sulfide used at this time is in a gaseous state and is classified as a supertoxic substance that is very lethal to the environment, so handling and transportation in Korea is difficult. There is a difficult problem. Patent Document 2 also uses carbon disulfide, which is very toxic, and does not suggest any effect on improving thermal stability or easiness of transportation and storage.

US Registered Patent 4,359,452 (November 16, 1982) US Registered Patent 6,555,087 (2003.04.29)

It is intended to provide a method for manufacturing insoluble sulfur that is environmentally friendly and has improved thermal stability by applying liquid sulfide, which is readily available in Korea and is easy to handle and transport.

In addition, it is not limited to the technical problems as described above, and it is obvious that another technical problem may be derived from the following description.

According to one embodiment of the disclosure, the method for preparing insoluble sulfur is ethyldisulfide, methyldisulfide, propyldisulfide, diethyldisulfide, dimethyldisulfide in liquid sulfur. (Dimethyldisulfide), and adding at least one sulfide selected from the group consisting of dipropyldisulfide, followed by mixing to prepare an organic sulfur compound.

In addition, after step (a), (b) preparing sulfur vapor by heating the organosulfur compound, (c) quenching the sulfur vapor with carbon disulfide to separate and recover insoluble sulfur from the sulfur vapor And (d) it may further comprise the step of coating by adding oil to the insoluble sulfur.

According to one embodiment disclosed in the present specification, in the method for producing insoluble sulfur, by performing the step of adding sulfide to liquid sulfur before the step of heating and vaporizing the sulfur, it has excellent thermal stability and high insoluble sulfur compared to the existing one. There is an effect that can be obtained with purity. In addition, since the organic sulfur compound mixed with sulfide and sulfur is vaporized and quenched, it is environmentally friendly and the manufacturing process is relatively simple, thereby improving production efficiency.

1 is a process diagram for explaining a method for producing insoluble sulfur according to an embodiment of the disclosure in the present specification.

Hereinafter, with reference to the accompanying drawings, the configuration and effects of preferred embodiments will be described. For reference, in the following drawings, each component is omitted or schematically illustrated for convenience and clarity, and the size of each component does not reflect the actual size. In addition, the same reference numerals refer to the same components throughout the specification, and reference numerals for the same components in individual drawings will be omitted.

Hereinafter, the method for producing insoluble sulfur of the present invention will be described in detail with reference to the drawings.

1 is a process diagram for explaining a method for producing insoluble sulfur according to an embodiment of the disclosure disclosed herein.

Referring to FIG. 1 , first, sulfide is added to liquid sulfur and then mixed to prepare an organic sulfur compound (S10).

Liquid sulfur, which is the main raw material of the disclosed subject matter, may be in a temperature range of 130 to 150° C. in a state in which sulfur is melted. Sulfur is a yellow non-metallic solid at room temperature, which burns with a blue flame, releasing sulfur dioxide with a very strong and foul odor. In the solid state, it exists as a ring-crown-shaped S8, and has about 30 allotropes with different crystal structures depending on conditions. On the other hand, when liquid sulfur is quenched in water, it becomes a tough and elastic material like yellowish-brown rubber (structured chain, lattice-shaped sulfur). When a liquid is heated again to a high temperature, it becomes a gas, but 　 contains molecules such as S8 (yellow), S6, S4 (red), S2 (yellow) 　. As the temperature increases, it dissociates into monoatomic 　S.

Sulfur is classified into soluble sulfur, which is insoluble in water and dissolved by carbon disulfide (carbon disulfide), and insoluble sulfur (polymer sulfur), which is not dissolved by carbon disulfide. Insoluble sulfur is difficult to cause cracking and blooming because the solubility of rubber is lower than that of soluble sulfur, and since it serves to crosslink and synthesize other additives, it is an indispensable additive in rubber manufacturing. Therefore, when manufacturing various rubber products such as tires, rubber conveyor belts, high-pressure hoses, and special rubbers, about 5% is added as a crosslinking agent and used.

On the other hand, insoluble sulfur can be produced by using sulfur obtained as a by-product in the desulfurization process of an oil refinery, and in this case, it is possible to create more added value by lowering the manufacturing cost of the existing insoluble sulfur.

Based on 100 parts by weight of liquid sulfur, 0.001 to 10 parts by weight of sulfide, preferably 0.001 to 5 parts by weight, and most preferably 2 to 4 parts by weight, after adding it at a temperature of 120 to 160°C, preferably 130 to 150°C The organic sulfur compound can be prepared by mixing and stirring at a rate of 10 to 3600 RPM, preferably 100 to 300 RPM, for 10 minutes to 12 hours, preferably 30 minutes to 90 minutes, and most preferably 50 minutes to 70 minutes. have.

When the sulfide is added in an amount of less than 0.001 parts by weight, the yield and thermal stability of insoluble sulfur may be lowered, and when it is added in excess of 10 parts by weight, the hydrocarbon is carbonized and turned into ash, so that black spots on the surface of the final product, insoluble sulfur It is undesirable because it can affect the color of insoluble sulfur to be produced and lower the quality.

If the mixing temperature is less than 120 ° C, it is difficult to react with sulfide in a liquid state having a viscosity of 10 centipoise because sulfur is in a solid state, and when it exceeds 160 ° C, the viscosity of sulfur is 10,000 centipoise or more It is difficult to react with low-viscosity sulfides, and the reaction rate may decrease.

If the mixing speed is less than 10 RPM, the mixing time may be long, and if it exceeds 3600 RPM, overheating may occur, so that the sulfide does not react with the sulfur and the sulfide does not react with the sulfur, but reacts with its own polymer and reacts rapidly, resulting in unwanted reactions.

If the mixing time is less than 10 minutes, it is difficult to sufficiently mix the liquid sulfur and the sulfide, and if it exceeds 12 hours, an undesired self-polymer reaction may occur, and the resulting mixing time may not be very large.

On the other hand, sulfide refers to a compound that binds to a sulfide ion in the chemical formula or contains such an ion, and in a broader sense, also collectively refers to a large group of inorganic and organic compounds containing sulfur, and has a purity of 90-100 in a liquid state. %, and impurities may be included in an amount of 0.0001 to 10 parts by weight based on 100 parts by weight of the sulfide. In particular, when an oxide containing oxygen among impurities is present, the SO _X component is generated and may adversely affect all mechanical equipment and materials, so it is preferable to control the oxide to be contained in an amount of 0.0001 to 0.1 parts by weight based on 100 parts by weight of the sulfide. do. When the content of the oxide exceeds 0.1 parts by weight, heat loss and ash content are increased, thereby adversely affecting the yield of insoluble sulfur and may be harmful to the environment. The group consisting of sulfides as ethyldisulfide, methyldisulfide, propyldisulfide, diethyldisulfide, dimethyldisulfide, and dipropyldisulfide at least one selected from, preferably at least one selected from the group consisting of dimethyldisulfide, and dipropyldisulfide, most preferably dimethyldisulfide, and dipropyldisulfide ( Dipropyldisulfide) may be formulated in a weight ratio of 1: 0.5 to 1.5.

Then, the organic sulfur compound is heated (S20).

The organic sulfur compound prepared in step S10 is put into a reactor and heated to a temperature of 500 to 700° C., which is a temperature above the evaporation point, preferably 550 to 650° C. to prepare sulfur vapor.

If the heating temperature is less than 500 ° C, it is difficult to obtain the desired molecular structure of sulfur, and when it exceeds 700 ° C, not only the steel material of the reactor is corroded by the sulfur, but also an explosion accident may occur due to the change in the structure of the sulfur. Can not do it. As the temperature increases, the pressure in the container also increases proportionally, so it is preferable to adjust the temperature to suit the situation while monitoring the state of the organic sulfur compound.

When the above-described temperature condition is satisfied, ^{the evaporation pressure condition of 1 kg/cm 2} is satisfied, so that it may be possible to obtain sulfur having a molecular structure of S1.

Thereafter, the sulfur vapor is quenched with carbon disulfide to separate and recover insoluble sulfur from the sulfur vapor (S30).

The sulfur vapor prepared in step S20 is sent to a cooler (Quencher) and carbon disulfide is supplied to the cooler at a flow rate of 400 to 600 kg/h to rapidly cool the temperature of the sulfur vapor to 30 to 60 °C. At this time, the carbon disulfide may be filled to occupy 30 to 50% of the cooler, and the temperature of the cooled carbon disulfide may be maintained at 30 to 60° C. through the heat exchanger. The amount of carbon disulfide circulation and temperature can be adjusted with a cooling heat exchanger according to the supply amount of sulfur vapor, and an agitator is installed at the bottom of the quenching zone to mix insoluble sulfur and carbon disulfide evenly so that there is no clogging of the pipe. It is preferable to do Then, only the solid content, that is, insoluble sulfur, was separated and recovered using a centrifuge.

Finally, oil is added to insoluble sulfur and coated (S40).

Based on 100 parts by weight of the insoluble sulfur recovered in step S30, 1 to 40 parts by weight, preferably 10 to 33 parts by weight, of an oil of 20 to 30° C. is coated on the surface of insoluble sulfur at room temperature of 25 to 27° C. can do.

When the temperature and content of the above-described oil are satisfied, the viscosity of the oil is properly maintained, so that insoluble sulfur can be uniformly coated as a whole.

The oil is a process oil, and one oil selected from the group consisting of naphthenic oil, aromatic oil, and combinations thereof may be used.

When the coating step as described above is completed, the final insoluble sulfur is obtained. Such insoluble sulfur may contain 80% or more of insoluble sulfur polymer in a polymer state having a dark yellow color and thermal stability.

Example 1. Preparation of insoluble sulfur

After adding 0.5 parts by weight of methyldisulfide as sulfide to 100 parts by weight of sulfur, the mixture was mixed at 140° C. at 200 RPM for 1 hour. Then, it was put into a reactor and evaporated by raising the temperature to 550° C. or more, and the evaporated sulfur was sent to a quenching zone and quenched with carbon disulfide. Then, the solid content was separated by a centrifuge and dried to prepare insoluble sulfur.

Example 2. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 3 parts by weight of methyldisulfide was added as a sulfide.

Example 3. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 0.5 parts by weight of propyldisulfide was added as a sulfide.

Example 4. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 3 parts by weight of propyldisulfide was added as a sulfide.

Example 5. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 0.5 parts by weight of dimethyldisulfide was added as a sulfide.

Example 6. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 3 parts by weight of dimethyldisulfide was added as a sulfide.

Example 7. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 0.5 parts by weight of dipropyldisulfide was added as a sulfide.

Example 8. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 3 parts by weight of dipropyldisulfide was added as a sulfide.

Example 9. Preparation of Insoluble Sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 1.5 parts by weight of dipropyldisulfide and 1.5 parts by weight of dimethyldisulfide were added as sulfides.

Comparative Example 1. Preparation of insoluble sulfur

100 parts by weight of sulfur at 130° C. was put into a reactor, the temperature was raised to 550° C. or higher, and evaporated, and the evaporated sulfur was sent to a quenching zone and quenched with carbon disulfide. Then, the solid content was separated by a centrifuge and dried to prepare insoluble sulfur.

Comparative Example 2. Preparation of insoluble sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 6 parts by weight of propyldisulfide was added as a sulfide.

Comparative Example 3. Preparation of insoluble sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 6 parts by weight of dipropyldisulfide was added as a sulfide.

Comparative Example 4. Preparation of insoluble sulfur

Insoluble sulfur was prepared in the same manner as in Example 1, except that 3 parts by weight of dimethyldisulfide having a purity of 80% was added as a sulfide.

Experimental Example 1. Physical property evaluation

In order to evaluate the physical properties of insoluble sulfur according to Examples 1 to 9 and Comparative Examples 1 to 4, an experiment was conducted as follows.

By adopting the method stipulated by ASTM (American Society for Testing and Materials, ASTM D 4578), the purity of insoluble sulfur (Insoluble Sulfur(min) on total S), that is, the weight of insoluble sulfur in total sulfur, and acidity (Acidity, as H ₂₎ SO ₄ (max)), ash (Ash content (max)), and heat loss (Heat loss (max)) were measured, respectively, and the results are shown in Tables 1 and 2 below. In addition, the color of insoluble sulfur was visually evaluated and shown in Tables 1 and 2.

For thermal stability, purity (% insoluble in total sulfur) was measured after exposing the insoluble sulfur of Examples and Comparative Examples to 105° C. for 15 minutes according to ASTM D 4578 test method. And, compared to the purity of insoluble sulfur measured at room temperature before exposure to heat, thermal stability was evaluated.

Tables 1 and 2 are tables showing experimental results.

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 color yellow yellow yellow yellow yellow yellow yellow Purity¹ (%) 85.4 93.4 86.4 94.4 86.9 95.5 84.4 Acidity (H ₂ SO ₄ ), (%) 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Ash (%) 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Heat loss (%) 1.72 1.74 1.73 1.71 1.74 1.70 1.70 thermal stability
(Purity after heat exposure, %) 76.9 90.9 77.9 91.4 77.9 92.9 73.9 Purity¹ means the purity of insoluble sulfur at room temperature (insoluble content % of total sulfur), and thermal stability means the purity (insoluble content % of total sulfur) after maintaining insoluble sulfur at 105℃ for 15 minutes.

division Example 8 Example 9 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 color yellow yellow yellow black spot black spot yellow water(%) 95.4 94.2 82.4 85.2 83.2 83.5 Acidity (H ₂ SO ₄ ), (%) 0.01 0.01 0.01 0.02 0.01 0.03 Ash (%) 0.01 0.01 0.01 0.03 0.03 0.21 Heat loss (%) 1.78 1.74 1.77 1.72 1.79 2.15 thermal stability
(Purity after heat exposure, %) 92.9 91.6 73.9 78.2 76.8 79.9

According to the results of Tables 1 and 2, it was confirmed that Examples 1 to 9 showed overall superior results in all items compared to Comparative Examples 1 to 4. In particular, Examples 6 and 8 using dimethyldisulfide and dipropyldisulfide alone, and dimethyldisulfide and dipropyldisulfide in a weight ratio of 1:1 In the case of Example 9, which was used in combination with , there was no significant change in the purity before and after heat exposure, so it was found that the thermal stability was somewhat improved. Although it exhibited a high level of thermal stability, it showed relatively low values in acidity, ash, and heat loss, and in Comparative Examples 2 and 3 containing an excessive amount of sulfide, black spots were confirmed on the surface of insoluble sulfur.

Although preferred embodiments of the present invention have been described with reference to the accompanying drawings, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and represent all of the technical spirit of the present invention. Therefore, it should be understood that there may be various equivalents and modifications that can be substituted for them at the time of filing the present application. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following claims rather than the detailed description, and the meaning and scope of the claims and their All changes or modifications derived from the concept of equivalents should be construed as being included in the scope of the present invention.

Claims (7)

(a) Ethyldisulfide, methyldisulfide, propyldisulfide, diethyldisulfide, dimethyldisulfide, and dipropyldisulfide in liquid sulfur A method for producing insoluble sulfur, comprising the step of preparing an organic sulfur compound by adding one or more sulfides selected from the group consisting of and mixing them.
According to claim 1,
After step (a),
(a) preparing sulfur vapor by heating the organosulfur compound;
(b) separating and recovering insoluble sulfur from the sulfur vapor by quenching the sulfur vapor with carbon disulfide; and
(c) coating the insoluble sulfur by adding oil to the insoluble sulfur;
According to claim 1,
In the step (a), the sulfide is added in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of liquid sulfur.
According to claim 1,
The mixing in step (a) is a method of producing insoluble sulfur carried out for 10 minutes to 12 hours at a temperature of 120 ~ 160 ℃ at a rate of 10 ~ 3600 RPM.
3. The method of claim 2,
The heating in step (b) is a method for producing insoluble sulfur that is carried out at a temperature of 500 ~ 700 ℃.
3. The method of claim 2,
The rapid cooling in step (c) is a method for producing insoluble sulfur that is carried out at a temperature of 30 to 60 ℃.
3. The method of claim 2,
In step (d), the coating is carried out by spraying 1 to 40 parts by weight of oil on the surface of insoluble sulfur with respect to 100 parts by weight of insoluble sulfur, wherein the oil is in a temperature range of 20 to 30 ° C. Method of producing insoluble sulfur .

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