Process for the recovery of sulphur and organic stabilizer from a carbon disulphide solution containing sulphur and organic stabilizer

Abstract

A method for recovering sulfur and organic stabilizer from a carbon disulfide solution containing organic stabilizer and sulfur is characterized by first adding a certain amount of water to the carbon disulfide solution, then gradually raising the temperature to vaporize and condense the carbon disulfide for recovery. Finally, the organic stabilizer floats on the water surface, while the sulfur crystallizes below the surface. The sulfur is separated from the water surface, and the organic stabilizer is separated from the surface. The separated crude sulfur is added to a low-molecular-weight hydrocarbon solvent, heated under reflux, then separated, and finally vacuum dried to obtain sulfur.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals and relates to a method for recovering sulfur and organic stabilizers from a carbon disulfide solution containing organic stabilizers and sulfur. It belongs to the International Patent Classification C10B. Background Technology

[0002] In the production of insoluble sulfur, carbon disulfide is used as an extractant to extract common sulfur from the insoluble sulfur. This results in the carbon disulfide containing sulfur. Various stabilizers are also added to the carbon disulfide to improve the high-temperature stability of the insoluble sulfur. Some of these stabilizers are organic stabilizers, primarily olefins and aromatic ring organic compounds. In the carbon disulfide recovery process, evaporation is generally used to evaporate the carbon disulfide, followed by condensation and recovery. During this process, as the carbon disulfide continues to evaporate and the evaporation temperature increases, the sulfur reacts chemically with the organic stabilizers to form sulfides. These sulfides mostly have an unpleasant, pungent odor, are harmful to human health, and also affect the quality of the sulfur product and the recovery and reuse of the stabilizers. Therefore, how to efficiently and safely recover sulfur and stabilizers from carbon disulfide solutions is of great significance to the development of the insoluble sulfur industry. Summary of the Invention

[0003] This patent provides a novel method for effectively recovering sulfur and stabilizers from carbon disulfide solution while avoiding chemical reactions between sulfur and organic stabilizers. The method includes the following components:

[0004] A method for recovering sulfur and organic stabilizer from a carbon disulfide solution containing organic stabilizer and sulfur is characterized by first adding a certain amount of water to the carbon disulfide solution, then gradually increasing the temperature to vaporize and condense the carbon disulfide for recovery. Finally, the organic stabilizer floats on the water surface, while the sulfur crystallizes below the surface. The sulfur is separated from the water surface, and the organic stabilizer is separated from the surface. The separated crude sulfur is added to a low-molecular-weight hydrocarbon solvent, heated under reflux, then separated, and finally vacuum dried to obtain sulfur. The specific operation method is as follows:

[0005] (1) The carbon disulfide solution containing organic stabilizer and sulfur is loaded into a container equipped with a heating and condensation recovery device;

[0006] (2) Add a certain amount of water to a carbon disulfide solution containing organic stabilizer and sulfur, and then heat the container until the carbon disulfide boils.

[0007] (3) Collect the evaporated carbon disulfide, condense and cool it to recover the carbon disulfide;

[0008] (4) Continue evaporating carbon disulfide until it is completely evaporated;

[0009] (5) Raise the temperature to 80-90℃ and keep water in the system. If the water evaporates, you need to add water to the container.

[0010] (6) Cool the container to below 40°C, then separate the lower sulfur layer, then separate the water layer, and obtain the upper oil layer as the recovered organic stabilizer.

[0011] (7) Place the separated crude sulfur into a container, add solvent, heat until the solvent boils, and return the boiling solvent to the container through a condenser reflux device to continue evaporation and reflux. After a period of time, cool down to below 40°C to separate the solvent and sulfur. Heat the sulfur in a sealed container to 70-80°C, evacuate, and separate the residual solvent in the sulfur to obtain sulfur.

[0012] According to the method described above, the weight ratio of carbon disulfide solution containing organic stabilizer and sulfur to water is 3-1:1. Stirring is preferred during the evaporation process, and the evaporation temperature is controlled below 100°C. The industrial process is carried out using a reaction vessel, preferably supplemented by a carbon disulfide condensation and recovery system. The solvent for adding sulfur can be a C5-C8 low-molecular-weight alkanes, with pentane and hexane being preferred. The weight ratio of solvent to sulfur is 2-4:1.

[0013] The effects of the invention

[0014] Using the above method, sulfur, carbon disulfide, and organic stabilizers can be recovered from a carbon disulfide solution containing organic stabilizers and sulfur. The recovered carbon disulfide and organic stabilizers can be reused. By adding water, the reaction temperature can be controlled, allowing the organic stabilizer to float on the water surface. Even if not all the carbon disulfide evaporates, the organic stabilizer and sulfur can be separated, avoiding chemical reactions between sulfur and organic stabilizers during the recovery process, and ensuring the quality of sulfur. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Comparative Example 1:

[0017] In a certain process of producing insoluble sulfur, the carbon disulfide extract (a carbon disulfide solution containing organic stabilizers and sulfur) is produced. Its properties and composition are shown in Table 1, where stabilizer A is an olefin and stabilizer B is an alkenyl aromatic hydrocarbon.

[0018] Table 1 Properties of the extract

[0019]

[0020] 800 ml of extract containing stabilizer A was heated in a flask at different temperatures to extract carbon disulfide. The carbon disulfide evaporated and was recovered by condensation and cooling. However, carbon disulfide was always present in the flask, so the temperature was continuously increased. When the temperature exceeded 100°C, the sulfur and stabilizer in the flask reacted. The stabilizer gradually turned from clear and transparent to yellow, and the sulfur gradually began to melt, turning from yellow to dark red, and had an unpleasant odor. The content of organic stabilizer in the sulfur reached more than 10%, and the sulfur and organic stabilizer were difficult to separate.

[0021] 800 ml of extract containing stabilizer B was heated in a flask at different temperatures to extract carbon disulfide. The carbon disulfide evaporated and was recovered by condensation and cooling. However, carbon disulfide was always present in the flask, so the temperature was continuously increased. When the temperature exceeded 98°C, the sulfur and stabilizer in the flask reacted. The stabilizer gradually turned from clear and transparent to red, and the sulfur gradually began to melt, changing from yellow to dark red, and had an unpleasant odor. The content of organic stabilizer in the sulfur reached more than 10%, and the sulfur and organic stabilizer were difficult to separate.

[0022] Therefore, it is determined that the temperature during the recovery of stabilizers should not exceed 100°C. Considering factors such as the ignition point of CS2 being 90°C, the temperature during the recovery process should not exceed 90°C.

[0023] Example 1:

[0024] Take 800 ml of the carbon disulfide extract containing stabilizer A from Comparative Example 1 into a 2000 ml three-necked flask, add 300 ml of water, and attach a condenser and receiving flask. Then heat to 46°C. Carbon disulfide begins to distill off. As carbon disulfide continues to distill off, the temperature of the extract also increases. When the temperature reaches 80°C, stop heating and slowly cool to 40°C. The system separates into three layers: a bottom layer of sulfur, a middle layer of water, and an upper layer of oil (organic stabilizer layer). Separate the water and oil layers, and separate the sulfur layer to recover the carbon disulfide. The purity is 99.6%, and it is reusable. The oil layer contains stabilizers and carbon disulfide, with stabilizers accounting for 27%, which can be added to the carbon disulfide for reuse. The recovered crude sulfur is yellow in color and contains 4.9% organic matter. 100g of the recovered crude sulfur is added to 100g of n-pentane and heated under reflux for 10 minutes. The n-pentane and sulfur are separated by filtration. The separated sulfur is placed in a vacuum drying oven at 70°C and vacuumed for 20 minutes. The dried sulfur is then removed, and the organic matter content is analyzed to be 1.6%, indicating that solvent reflux greatly reduces the organic matter content in the sulfur.

[0025] Example 2:

[0026] Take 1000 ml of the carbon disulfide extract containing stabilizer B from Comparative Example 1 into a 2000 ml three-necked flask, add 500 ml of water, and attach a condenser and receiving flask. Then heat to 50°C. Carbon disulfide begins to evaporate. As carbon disulfide continues to evaporate, the temperature of the extract also increases. When the temperature reaches 90°C, stop heating and slowly cool to 40°C. The system separates into three layers: a bottom layer of sulfur, a middle layer of water, and an upper layer of oil (organic stabilizer layer). Separate the water and oil layers, and the sulfur... The carbon disulfide recovered after separation was 99.6% pure and could be reused. The oil layer contained stabilizer and carbon disulfide, with the stabilizer content at 32%, which could be added to the carbon disulfide for reuse. The recovered crude sulfur was yellow in color and contained 4.2% organic matter. 100g of the recovered sulfur was added to 200g of n-hexane and heated under reflux for 20 minutes. The n-hexane and sulfur were separated by filtration. The separated sulfur was placed in a vacuum drying oven at 80°C and vacuumed for 30 minutes. The dried sulfur was then removed and analyzed, and the organic matter content was found to be 1.4%.

[0027] As can be seen from the above examples, the method of this patent can separate carbon disulfide, sulfur, and organic stabilizers from carbon disulfide extract, wherein the carbon disulfide and organic stabilizers can be reused. Of course, the above description is merely one embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of this invention.

Claims

1. A method for recovering sulfur and organic stabilizer from a carbon disulfide solution containing organic stabilizer and sulfur, characterized in that... A certain amount of water is first added to the carbon disulfide solution, and then the temperature is gradually increased to allow the carbon disulfide to continuously vaporize, condense, and be recovered, ultimately resulting in... The organic stabilizer floats on the water surface, while the sulfur crystallizes below the surface. The sulfur is then separated from the water surface, and the organic stabilizer is separated from the water surface. The separated crude sulfur was added to a low-molecular-weight hydrocarbon solvent, heated under reflux, then separated and vacuum dried to obtain sulfur. Specific procedures are as follows. The method is as follows: (1) The carbon disulfide solution containing organic stabilizer and sulfur is loaded into a container equipped with heating and condensation recovery device; (2) Add a certain amount of water to a carbon disulfide solution containing organic stabilizer and sulfur, and then heat the container until the carbon disulfide is dissolved. Carbon boiling; (3) Collect the evaporated carbon disulfide, condense and cool it to recover the carbon disulfide; (4) Continue evaporating carbon disulfide until it is completely evaporated; (5) Raise the temperature to 80-90℃ and keep water in the system. If the water evaporates, you need to add water to the container. The container was cooled to below 40°C, then the lower sulfur layer was separated, followed by the water layer, yielding the upper oil layer for recovery. Organic stabilizers; (6) Place the separated crude sulfur into a container, add solvent, heat until the solvent boils, and reflux the boiling solvent through condensation. The equipment returns to the container for continued evaporation and reflux. After a period of time, the temperature is lowered to below 40°C to separate the solvent and sulfur. The sulfur is then stored in a sealed container. The mixture is heated to 70-80℃ in the apparatus, then evacuated to separate the residual solvent from the sulfur, yielding the sulfur. The temperature during the recovery process is... The temperature should not exceed 90℃.

2. The method according to claim 1, characterized in that the weight ratio of the carbon disulfide solution containing the organic stabilizer and sulfur to water is... The ratio is 3 to 1:

1.

3. The method according to claim 1, characterized in that... The reaction is carried out in a reactor, supplemented by a carbon disulfide condensation and recovery system.

4. The method according to claim 1, characterized in that... The solvent added to the sulfur is a C5-C8 low molecular weight alkane.

5. The method according to claim 1, characterized in that... The solvent used to add sulfur is a C6 alkane.

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