Preparation process for producing insoluble sulfur by high-temperature liquid sulfur atomization direct method

Abstract

The invention discloses a preparation process for producing insoluble sulfur by a high-temperature liquid sulfur atomization direct method. The preparation process comprises the following steps: step 1, putting industrial sulfur into a heating container driving a stirring mechanism for heating and melting; 2, mixing diphenyl disulfide, mercaptoethanol and a sulfur solution; 3, atomizing the mixture by using an ultrasonic atomizer and carrying out a polymerization reaction, 4, introducing the polymerized material into a cooling tower, and rapidly cooling the liquid by using a supercritical carbon dioxide and liquid nitrogen mixture, and 5, putting the rapidly cooled particles into a supercritical carbon dioxide extraction kettle, and 6, carrying out in-situ coating by using a supercritical carbon dioxide solution of fluorosilane. Supercritical carbon dioxide is used for rapid cooling, the specific surface area is large, the supercritical carbon dioxide is in full contact with the supercritical carbon dioxide, the supercritical carbon dioxide rapidly permeates into sulfur particles through the strong solubility and diffusivity of the supercritical carbon dioxide, and uniform cooling is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of insoluble sulfur, in particular to a preparation process for producing insoluble sulfur by directly atomizing high-temperature liquid sulfur. Background Art

[0002] Insoluble sulfur is a polymeric sulfur obtained by special processing of ordinary sulfur. The number of sulfur atoms on its molecular chain is as high as hundreds to thousands, forming an amorphous or low-crystallinity chain structure.

[0003] The direct production process of insoluble sulfur using high-temperature liquid sulfur atomization is an efficient, controllable, and industrially applicable process. Through key steps such as high-temperature melting, atomization, rapid cooling, and post-processing, this process converts ordinary sulfur into high-value-added insoluble sulfur.

[0004] In the process of implementing the existing high-temperature liquid flow atomization process to produce insoluble sulfur, in order to improve thermal stability, the material after the polymerization reaction needs to be rapidly cooled. However, rapid cooling can easily lead to hardening of the particle surface and incomplete internal polymerization, forming a hard-outer-soft-inner structure, which increases the insoluble sulfur content. Therefore, we proposed a preparation process for producing insoluble sulfur by direct method of high-temperature liquid sulfur atomization. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation process for producing insoluble sulfur by directly atomizing high-temperature liquid sulfur, which solves the problem proposed in the background art that rapid cooling easily leads to surface hardening of particles, incomplete internal polymerization, forming a hard outer and soft inner structure, and increasing the insoluble sulfur content.

[0006] To achieve the above object, the present invention provides the following technical solution: a preparation process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur, characterized in that it includes the following process steps:

[0007] Step 1: Put industrial sulfur into a heating container with a stirring mechanism to heat and melt it for 2 hours to obtain a sulfur solution;

[0008] Step 2: adding diphenyl disulfide and mercaptoethanol into a sand mill, introducing a sulfur solution into the sand mill, and grinding in the sand mill for 30 minutes to obtain a mixture;

[0009] Step 3: Using an ultrasonic atomizer, the mixture is atomized into droplets and introduced into a polymerization reactor. A mixture of supercritical carbon dioxide and nitrogen is then introduced into the polymerization reactor to mix the gas and liquid sulfur. The mixture is then moved to the polymerization reactor. During the polymerization reaction, the cyclic molecules in the liquid sulfur open at high temperatures to form linear or branched sulfur chains. The polymerization temperature is 250-300°C.

[0010] Step 4: The polymerized material is then introduced into a cooling tower, where the liquid is rapidly cooled by a mixture of supercritical carbon dioxide and liquid nitrogen;

[0011] Step 5: Place the quenched pellets into a supercritical carbon dioxide extraction kettle and circulate the extraction for 10 minutes to remove residual soluble sulfur;

[0012] Step 6: In-situ coating using a supercritical carbon dioxide solution of fluorosilane to form a 10 nm fluorinated hydrophobic layer;

[0013] Step 7: Sieving through ultrasonic vibration screen to obtain insoluble sulfur.

[0014] As a preferred embodiment of the present invention, the rapid cooling in step 4 is divided into three stages of cooling. The first stage of cooling is to cool the polymer with supercritical carbon dioxide and liquid nitrogen, and the cooling temperature is -40°C. The second stage of cooling is to cool the supercritical carbon dioxide alone, and the cooling temperature is -50°C. The third stage of cooling is to cool the supercritical carbon dioxide alone, and the temperature is 25°C.

[0015] As a preferred embodiment of the present invention, the mass ratio of diphenyl disulfide to mercaptoethanol is 1:1.8.

[0016] As a preferred embodiment of the present invention, the extraction pressure in step five is 30 MPa and the temperature is 40°C.

[0017] As a preferred embodiment of the present invention, the coating pressure condition in step six is 10 MPa and the temperature condition is 35°C.

[0018] As a preferred embodiment of the present invention, in step 1, the heating temperature is set to 170° C. and the stirring speed is set to 50 rpm.

[0019] As a preferred embodiment of the present invention, the liquid sulfur flow rate in step three is 150 kg / h.

[0020] As a preferred embodiment of the present invention, the mixing ratio of the supercritical carbon dioxide and nitrogen mixed gas in step three is 1:3.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention atomizes the liquid by ultrasonic atomization, thereby increasing the surface energy of the droplets, accelerating the ring-opening polymerization reaction, and facilitating improved polymerization reaction effects. Furthermore, supercritical carbon dioxide is used for rapid cooling, resulting in a large specific surface area and more complete contact with the supercritical carbon dioxide. The strong solubility and diffusivity of supercritical carbon dioxide are utilized to rapidly penetrate into the interior of the sulfur particles, achieving uniform cooling and facilitating avoidance of structural defects caused by a large internal and external temperature difference in conventional rapid cooling methods.

[0023] During the polymerization reaction, the strong diffusivity of supercritical carbon dioxide allows a micron-sized carbon dioxide adsorption layer to quickly form on the droplet surface, inhibiting droplet merging and improving atomization uniformity. Supercritical carbon dioxide also accelerates heat transfer within the droplets, which helps improve polymerization reaction efficiency.

[0024] The use of nano-scale fluorosilane to form a coating layer is beneficial to improving the hydrophobicity, thereby helping to reduce the sulfur migration rate and thus helping to extend the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0026] Figure 1 The present invention is a process flow chart for producing insoluble sulfur by a direct method of atomizing high-temperature liquid sulfur. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0028] Example 1

[0029] Industrial sulfur is placed in a heating container with a stirring mechanism for heating and melting for 2 hours, heated to 170°C, and stirred at 50 rpm to obtain a sulfur solution; diphenyl disulfide and mercaptoethanol are added to a sand mill at a mass ratio of 1:1.8, and the sulfur solution is introduced into the sand mill and ground in the sand mill for 30 minutes to obtain a mixture; droplets of the mixture are atomized by an ultrasonic atomizer and introduced into a polymerization reactor at a liquid sulfur flow rate of 150 kg / h, and a mixed gas of supercritical carbon dioxide and nitrogen is introduced into the polymerization reactor at a mixing ratio of 1:3 to mix the gas and liquid sulfur, and then move to the polymer; during the polymerization reaction, the cyclic molecules in the liquid sulfur open at high temperature to form linear or branched sulfur chains, and the polymerization temperature is 250-300°C; and the polymerized liquid sulfur is then added to the polymer reactor. The material is introduced into a cooling tower, and the liquid is rapidly cooled by a mixture of supercritical carbon dioxide and liquid nitrogen. The rapid cooling is divided into three stages. The first stage is to cool the polymer with supercritical carbon dioxide and liquid nitrogen at a temperature of -40°C. The second stage is to cool the supercritical carbon dioxide alone at a temperature of -50°C. The third stage is to cool the supercritical carbon dioxide alone at a temperature of 25°C. The rapidly cooled particles are put into a supercritical carbon dioxide extraction kettle and circulated for extraction for 10 minutes at a pressure of 30 MPa and a temperature of 40°C to remove residual soluble sulfur. In-situ coating is performed using a supercritical carbon dioxide solution of fluorosilane at a pressure of 10 MPa and a temperature of 35°C to form a 10 nm fluorinated hydrophobic layer. Insoluble sulfur is obtained by screening through an ultrasonic vibrating screen.

[0030] Example 2

[0031] Industrial sulfur is placed in a heating container with a stirring mechanism for heating and melting for 2 hours, heated to 170°C, and stirred at 50 rpm to obtain a sulfur solution; diphenyl disulfide and mercaptoethanol are added to a sand mill at a mass ratio of 1:1.8, and the sulfur solution is introduced into the sand mill and ground for 30 minutes to obtain a mixture; the mixture is atomized into droplets using an ultrasonic atomizer and introduced into a polymerization reactor at a liquid sulfur flow rate of 150 kg / h, and a mixed gas of supercritical carbon dioxide and nitrogen is introduced into the polymerization reactor at a mixing ratio of 1:3 to mix the gas and liquid sulfur, and then moved to the polymer; during the polymerization reaction, the cyclic molecules in the liquid sulfur are ring-opened at high temperature to form linear or branched sulfur chains, and the polymerization temperature is 260-300°C; and the polymerized sulfur is then The material is introduced into a cooling tower, and the liquid is rapidly cooled by a mixture of supercritical carbon dioxide and liquid nitrogen. The rapid cooling is divided into three stages. The first stage is to cool the polymer with supercritical carbon dioxide and liquid nitrogen at a temperature of -45°C. The second stage is to cool the supercritical carbon dioxide alone at a temperature of -55°C. The third stage is to cool the supercritical carbon dioxide alone at a temperature of 30°C. The rapidly cooled particles are put into a supercritical carbon dioxide extraction kettle and circulated for extraction for 10 minutes at a pressure of 30 MPa and a temperature of 40°C to remove residual soluble sulfur. In-situ coating is performed using a supercritical carbon dioxide solution of fluorosilane at a pressure of 10 MPa and a temperature of 35°C to form a 10 nm fluorinated hydrophobic layer. Insoluble sulfur is obtained by screening through an ultrasonic vibrating screen.

[0032] Example 3

[0033] Industrial sulfur is placed in a heating container with a stirring mechanism for heating and melting for 2 hours, heated to 165°C, and stirred at 50 rpm to obtain a sulfur solution; diphenyl disulfide and mercaptoethanol are added to a sand mill at a mass ratio of 1:1.8, and the sulfur solution is introduced into the sand mill and ground in the sand mill for 30 minutes to obtain a mixture; droplets of the mixture are atomized by an ultrasonic atomizer and introduced into a polymerization reactor at a liquid sulfur flow rate of 150 kg / h, and a mixed gas of supercritical carbon dioxide and nitrogen is introduced into the polymerization reactor at a mixing ratio of 1:3 to mix the gas and liquid sulfur, and then move to the polymer; during the polymerization reaction, the cyclic molecules in the liquid sulfur open at high temperature to form linear or branched sulfur chains, and the polymerization temperature is 240-270°C; and the polymerized sulfur is then The material is introduced into a cooling tower, and the liquid is rapidly cooled by a mixture of supercritical carbon dioxide and liquid nitrogen. The rapid cooling is divided into three stages. The first stage is to cool the polymer with supercritical carbon dioxide and liquid nitrogen at a temperature of -35°C. The second stage is to cool the supercritical carbon dioxide alone at a temperature of -45°C. The third stage is to cool the supercritical carbon dioxide alone at a temperature of 20°C. The rapidly cooled particles are put into a supercritical carbon dioxide extraction kettle and circulated for extraction for 10 minutes at a pressure of 30 MPa and a temperature of 40°C to remove residual soluble sulfur. In-situ coating is performed using a supercritical carbon dioxide solution of fluorosilane at a pressure of 10 MPa and a temperature of 35°C to form a 10 nm fluorinated hydrophobic layer. Insoluble sulfur is obtained by sieving through an ultrasonic vibrating screen.

[0034] The products obtained from the above three examples were tested to obtain the following data table:

[0035]

[0036] In summary, the present invention atomizes the liquid by ultrasonic atomization, thereby increasing the surface energy of the droplets, accelerating the ring-opening polymerization reaction, and being beneficial to improving the polymerization reaction effect, and utilizing supercritical carbon dioxide for rapid cooling, which has a large specific surface area and more sufficient contact with supercritical carbon dioxide. The strong solubility and diffusivity of supercritical carbon dioxide are utilized to quickly penetrate into the interior of the sulfur particles to achieve uniform cooling, which is beneficial to avoiding structural defects caused by excessive internal and external temperature differences in traditional rapid cooling methods; during the polymerization reaction stage, the strong diffusivity of supercritical carbon dioxide enables a micron-sized carbon dioxide adsorption layer to be quickly formed on the surface of the droplets, thereby inhibiting droplet merging and improving atomization uniformity, and supercritical carbon dioxide accelerates heat transfer inside the droplets, which is beneficial to improving the polymerization reaction efficiency; nano-scale fluorosilane is utilized to form a coating layer, which is beneficial to improving hydrophobic properties, thereby reducing sulfur mobility, and further contributing to extending service life.

[0037] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded as illustrative and non-restrictive in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are intended to be included therein.

[0038] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur, characterized in that: The process steps include: Step 1: Put industrial sulfur into a heating container with a stirring mechanism to heat and melt it for 2 hours to obtain a sulfur solution; Step 2: adding diphenyl disulfide and mercaptoethanol into a sand mill, introducing a sulfur solution into the sand mill, and grinding in the sand mill for 30 minutes to obtain a mixture; Step 3: Using an ultrasonic atomizer, the mixture is atomized into droplets and introduced into a polymerization reactor. A mixture of supercritical carbon dioxide and nitrogen is then introduced into the polymerization reactor to mix the gas and liquid sulfur. The mixture is then moved to the polymerization reactor. During the polymerization reaction, the cyclic molecules in the liquid sulfur open at high temperatures to form linear or branched sulfur chains. The polymerization temperature is 250-300°C. Step 4: The polymerized material is then introduced into a cooling tower, where the liquid is rapidly cooled by a mixture of supercritical carbon dioxide and liquid nitrogen; Step 5: Place the quenched pellets into a supercritical carbon dioxide extraction kettle and circulate the extraction for 10 minutes to remove residual soluble sulfur; Step 6: In-situ coating using a supercritical carbon dioxide solution of fluorosilane to form a 10 nm fluorinated hydrophobic layer; Step 7: Sieving through ultrasonic vibration screen to obtain insoluble sulfur.

2. The process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur according to claim 1, characterized in that: The rapid cooling in step 4 is divided into three stages of cooling. The first stage of cooling is to cool the polymer with supercritical carbon dioxide and liquid nitrogen at a temperature of -40°C. The second stage of cooling is to cool the polymer with supercritical carbon dioxide alone at a temperature of -50°C. The third stage of cooling is to cool the polymer with supercritical carbon dioxide alone at a temperature of 25°C.

3. The process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur according to claim 1, characterized in that: The mass ratio of diphenyl disulfide to mercaptoethanol is 1:1.

8.

4. The process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur according to claim 1, characterized in that: The extraction pressure in step 5 is 30 MPa and the temperature is 40°C.

5. The process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur according to claim 1, characterized in that: The coating pressure in step six is 10 MPa and the temperature is 35°C.

6. The process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur according to claim 1, characterized in that: In the step 1, the heating temperature is increased to 170° C. and the stirring speed is 50 rpm.

7. The process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur according to claim 1, characterized in that: The liquid sulfur flow rate in step 3 is 150 kg / h.

8. The process for producing insoluble sulfur by direct atomization of high-temperature liquid sulfur according to claim 1, characterized in that: The mixing ratio of the supercritical carbon dioxide and nitrogen mixed gas in step 3 is 1:3.

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