Method for recovering sulfur and organic stabilizer in carbon disulfide solution containing organic stabilizer and sulfur

Abstract

A method for recovering sulfur and an organic stabilizer in a carbon disulfide solution containing the organic stabilizer and the sulfur is characterized by comprising the following steps: adding a certain amount of water into the carbon disulfide solution, then gradually heating to gasify and condense carbon disulfide for recovery, and finally enabling the organic stabilizer to float on the water surface and the sulfur to crystallize under the water surface to obtain the sulfur-containing carbon disulfide solution. Sulfur is separated out from the water surface, and the organic stabilizer is separated out from the water surface. And adding the separated crude sulfur into a low-molecular hydrocarbon solvent, heating and refluxing, separating, and drying in vacuum to obtain the sulfur.

Description

Technical Field

[0001] The invention belongs to the field of petrochemical industry and relates to a method for recovering sulfur and organic stabilizer in a carbon disulfide solution containing organic stabilizer and sulfur. The international patent classification belongs to C10B. Background Art

[0002] In the production process of insoluble sulfur, carbon disulfide is used as an extractant to extract ordinary sulfur from insoluble sulfur, so that these carbon disulfides will contain sulfur. At the same time, various stabilizers will be added to carbon disulfide to improve the high-temperature stability of insoluble sulfur. Some stabilizers are organic stabilizers, and organic stabilizers are mainly olefins and aromatic ring organic matter. In the process of carbon disulfide recovery, carbon disulfide is generally evaporated by evaporation, and then condensed and cooled for recovery. In this process, as carbon disulfide continues to evaporate, the evaporation temperature continues to increase, and sulfur will react chemically with the organic stabilizer to generate sulfides. Most of these sulfides have unpleasant irritating odors, which are harmful to the human body. At the same time, they also affect the product quality of sulfur and the recovery and reuse of stabilizers. Therefore, how to efficiently and safely recover sulfur and stabilizers in carbon disulfide solution is of great significance to the development of the insoluble sulfur industry. Summary of the invention

[0003] This patent provides a new method that can effectively recover sulfur and stabilizers in carbon disulfide solution while avoiding chemical reactions between sulfur and organic stabilizers. The method includes the following parts:

[0004] A method for recovering sulfur and organic stabilizer in 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 gasify and condense the carbon disulfide for recovery, and finally the organic stabilizer is floated on the water surface, and the sulfur is crystallized under the water surface, and the sulfur is separated from the water surface, and the organic stabilizer is separated from the water surface, and the separated crude sulfur is added with a low molecular hydrocarbon solvent, heated and refluxed, and then separated and vacuum dried to obtain sulfur. The specific operation method is as follows:

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

[0006] (2) adding a certain amount of water to a carbon disulfide solution containing an organic stabilizer and sulfur, and then heating the container until the carbon disulfide boils;

[0007] (3) collecting, condensing and cooling the evaporated carbon disulfide to recover the carbon disulfide;

[0008] (4) continuing to evaporate carbon disulfide until the carbon disulfide is completely evaporated;

[0009] (5) Raise the temperature to 80-90°C and keep water in the system. If the water evaporates completely, add water to the container;

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

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

[0012] According to the method described above, the weight ratio of the carbon disulfide solution containing organic stabilizer and sulfur to water is 3-1:1, stirring is preferably performed during the evaporation process, the evaporation temperature is controlled below 100°C, and the industrial process is carried out using a reactor, preferably assisted by a carbon disulfide condensation recovery system. The solvent to which sulfur is added can be C5-C8 low molecular weight alkane, preferably pentane and hexane. The weight ratio of the solvent to sulfur is 2-4:1.

[0013] Effects of the Invention

[0014] According to the above method, sulfur, carbon disulfide and organic stabilizer can be recovered from the carbon disulfide solution containing organic stabilizer and sulfur. The carbon disulfide and organic stabilizer can be reused after recovery. The reaction temperature can be controlled by adding water so that the organic stabilizer can float on the water surface. Even if the carbon disulfide is not completely evaporated, the organic stabilizer and sulfur can be separated, thereby avoiding chemical reaction between the sulfur and the organic stabilizer during the recovery process, and the quality of the sulfur can also be guaranteed. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] Comparative Example 1:

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

[0018] Table 1 Extract properties

[0019]

[0020] Take 800 ml of the extract containing stabilizer A and heat the carbon disulfide extract in a flask at different temperatures. The carbon disulfide evaporates and is recovered through condensation and cooling. However, there is always carbon disulfide in the flask, so the temperature is kept rising. When the temperature exceeds 100°C, the sulfur and the stabilizer in the flask react, and the stabilizer gradually turns yellow from clear and transparent, and the sulfur gradually begins to melt from yellow to dark red with an unpleasant odor. The content of organic stabilizer in sulfur reaches more than 10%, and sulfur and organic stabilizer are difficult to separate.

[0021] Take 800 ml of the extract containing stabilizer B and heat the carbon disulfide extract in a flask at different temperatures. The carbon disulfide evaporates and is recovered through condensation and cooling. However, there is always carbon disulfide in the flask, so the temperature is kept rising. When the temperature exceeds 98°C, the sulfur and the stabilizer in the flask react, and the stabilizer gradually turns red from clear and transparent, and the sulfur gradually begins to melt from yellow to dark red, and has an unpleasant odor. The content of organic stabilizer in sulfur reaches more than 10%, and sulfur and organic stabilizer are difficult to separate.

[0022] Therefore, it is determined that the recovery of the stabilizer should not be higher than 100℃, and the comprehensive CS 2 Due to factors such as the ignition point of 90°C, the temperature should not be higher than 90°C during the recycling process.

[0023] Embodiment 1:

[0024] Take 800 ml of the carbon disulfide extract containing stabilizer A in Comparative Example 1 in a 2000 ml three-necked flask, add 300 ml of water, add a condenser and a receiving bottle, and then heat it to 46° C. Carbon disulfide begins to evaporate. As carbon disulfide continues to evaporate, the temperature of the extract also continues to increase. When the temperature of the extract is increased to 80° C., stop heating, and then slowly cool it to 40° C. The system is divided into three layers, the bottom layer is sulfur, the middle layer is a water layer, and the upper layer is an oil layer (organic stabilizer layer). The water layer and the oil layer are separated, and the sulfur layer is separated, and the obtained carbon disulfide is recovered. The purity is 99.6% and it can be reused. The oil layer contains stabilizer and carbon disulfide, of which the stabilizer content is 27%, which can be added to carbon disulfide for reuse. The recovered crude sulfur is yellow in color and has an organic matter content of 4.9%. 100g of the recovered crude sulfur is added with 100g of n-pentane and heated to reflux for 10 minutes, the n-pentane and sulfur are filtered and separated, the separated sulfur is placed in a vacuum drying oven and vacuumed at 70°C for 20 minutes, the dried sulfur is taken out, and the organic matter content is analyzed to be 1.6%, indicating that the use of solvent reflux greatly reduces the organic matter content in sulfur.

[0025] Embodiment 2:

[0026] Take 1000ml of the carbon disulfide extract containing stabilizer B in Comparative Example 1 in a 2000ml three-necked flask, add 500ml of water, add a condenser and a receiving bottle, and then heat it to 50°C. Carbon disulfide begins to evaporate. As carbon disulfide continues to evaporate, the temperature of the extract also continues to increase. When the temperature of the extract is raised to 90°C, stop heating, and then slowly cool it to 40°C. The system is divided into three layers, the bottom layer is sulfur, the middle layer is a water layer, and the upper layer is an oil layer (organic stabilizer layer). The water layer and the oil layer are separated, and the sulfur The layers are separated, and the recovered carbon disulfide has a purity of 99.6% and can be reused; the oil layer contains stabilizer and carbon disulfide, of which the stabilizer content is 32%, and can be added to the carbon disulfide for reuse; the recovered crude sulfur is yellow in color and has an organic matter content of 4.2%; 100g of the recovered sulfur is added to 200g of n-hexane and heated to reflux for 20 minutes, the n-hexane and sulfur are filtered and separated, the separated sulfur is placed in a vacuum drying oven at 80°C and evacuated for 30 minutes, the dried sulfur is taken out, and the organic matter content is analyzed to be 1.4%.

[0027] From the above examples, it can be seen that the method of this patent can separate carbon disulfide, sulfur and organic stabilizer in carbon disulfide extract, and carbon disulfide and organic stabilizer can be reused. Of course, the above is only one embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are within the scope of protection of the claims of the present invention.

Claims

1. A method for recovering sulfur and an organic stabilizer from a carbon disulfide solution containing an 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 continuously gasify and condense the carbon disulfide for recovery, and finally the organic stabilizer is floated on the water surface and the sulfur is crystallized under the water surface, the sulfur is separated from the water surface and the organic stabilizer is separated from the water surface, a low molecular hydrocarbon solvent is added to the separated crude sulfur, the solution is heated to reflux, and then separated and vacuum dried to obtain sulfur. The specific operation method is as follows: (1) placing a carbon disulfide solution containing an organic stabilizer and sulfur into a container equipped with a heating and condensation recovery device; (2) adding a certain amount of water to a carbon disulfide solution containing an organic stabilizer and sulfur, and then heating the container until the carbon disulfide boils; (3) collecting, condensing and cooling the evaporated carbon disulfide to recover the carbon disulfide; (4) continuing to evaporate carbon disulfide until the carbon disulfide is completely evaporated; (5) Raise the temperature to 80-90°C and keep water in the system. If the water evaporates completely, add water to the container; The container is cooled to below 40°C, and then the lower sulfur layer is separated, and then the water layer is separated to obtain the upper oil layer as the recovered organic stabilizer; (6) Put the separated crude sulfur into a container, add a solvent, heat until the solvent boils, and return the boiling solvent to the container through a condensation reflux device to continue evaporation and reflux. After a period of time, cool it to below 40° C. to separate the solvent and sulfur. Heat the sulfur to 70-80° C. in a sealed container, evacuate it, and separate the residual solvent in the sulfur to obtain sulfur.

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 3 to 1:

1.

3. The method according to claim 1, characterized in that The temperature is controlled below 100℃.

4. The method according to claim 1, characterized in that The process is carried out using a reactor, assisted by a carbon disulfide condensation recovery system.

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

6. The method according to claims 1 and 5, characterized in that The solvent to which sulfur is added is C6 alkane.

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