Method for preparing high-quality sulfur through low-quality sulfur paste hydrothermal carbon sequestration upgrading

Abstract

According to the technical scheme, the method comprises the following steps that firstly, the low-quality sulfur paste is crushed and screened, and turbid liquid with a certain concentration is prepared from the low-quality sulfur paste and a solvent according to the mass ratio; 2, transferring the turbid liquid into a reaction kettle, heating to a reaction temperature, and carrying out a hydrothermal reaction to obtain a black solid; 3, the black solid is subjected to solid-liquid separation through a liquefying system, insoluble substances such as fixed carbon are removed through a filtering system, and high-quality sulfur is obtained through a condensing system; the method is wide in application range, can be used for purifying low-quality sulfur with high oil content, solid content and inorganic salt content, is simple in treatment process, greatly reduces the treatment cost, adopts water and low-quality sulfur paste as main raw materials, is low in site selection requirement and high in flexibility, mainly adopts heating and cooling as main means, is short in flow, is simple and convenient to operate, and is suitable for industrial production. And implementation and control in actual operation are facilitated, and the method is an effective way for resource utilization of low-quality sulfur.

Description

Technical Field

[0001] The present invention relates to the technical field of sulfur preparation, and in particular to a method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste. Background Art

[0002] Coal contains a large amount of sulfur, which is converted to hydrogen sulfide during the gasification and coking processes. Currently, wet redox methods are mostly used to convert hydrogen sulfide into sulfur. However, because raw coal gas carries impurities such as oil and dust, some of these oil and dust enter the sulfur product, reducing its quality. The sulfur produced by desulfurization equipment is an oily and dusty sulfur paste, which is unusable and is mostly disposed of as hazardous waste. To improve the utilization rate of low-quality sulfur, most companies have implemented supporting sulfur paste refining projects to address operational shortcomings of these plants.

[0003] Currently, the commonly used sulfur paste purification processes include melting sulfur, gasification, and extraction, of which melting sulfur is the most widely used. However, during the desulfurization process, the oil droplets are small, and the oil in low-quality sulfur paste is evenly distributed, making it difficult to remove. In the melting sulfur purification process for low-quality sulfur paste, the oil will mix with the molten sulfur and be difficult to separate; in the gasification purification process, the oil will gasify simultaneously with the sulfur, making gasification separation more difficult; and in the extraction purification process, the oil will enter the extractant, causing the extractant to foam and deteriorate. Therefore, the oil in low-quality sulfur paste is a key factor restricting the efficient purification of low-quality sulfur paste. To address the above problems, we propose a method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste, which solves the problems raised in the background technology.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste comprises the following steps:

[0007] Step 1: crush and sieve the low-quality sulfur paste, prepare a suspension of a certain concentration with the solvent according to the mass ratio, add a certain proportion of additives and stir for a certain time;

[0008] Step 2: Transfer the suspension obtained in step 1 into a reactor, raise the temperature to the reaction temperature for hydrothermal reaction, and obtain a black solid by hot filtration;

[0009] Step 3: The black solid is separated into solid and liquid by the liquefaction system, the fixed carbon and other insoluble substances are removed by the filtration system, and high-quality sulfur is obtained by the condensation system.

[0010] Preferably, the low-quality sulfur paste in step 1 refers to the high-oil sulfur paste produced during the process of removing H2S from raw coal gas using a direct oxidation method.

[0011] Preferably, the suspension solvent in step one is water and / or molten sulfur kettle water, preferably the solvent is sulfur kettle water, wherein the concentration of sulfur paste in the suspension solvent is 10-80% (mass concentration), preferably the concentration is 50% (mass ratio), and the additive in the suspension is a macromolecular surfactant, preferably the additive is polyvinyl pyrrolidone, the concentration is 0-5%, preferably the concentration is 0-0.05%.

[0012] Preferably, in the step 1, the suspension is stirred at a rate of 0 to 2000 rpm, preferably 600 rpm, and for a time of 0 to 60 minutes, preferably 30 minutes.

[0013] Preferably, the hydrothermal reaction reactor in step 2 is a closed reactor with a stirring function, the hydrothermal reaction stirring rate is 0-1000 rpm, preferably 400 rpm, the temperature is 40-300°C, preferably 60-180°C, the time is 0-300 minutes, preferably 30 minutes, and the filtration temperature after the reaction is 30-100°C, preferably 60°C.

[0014] Preferably, in step 3, the black solid suspension is introduced into a liquefaction system, and the sulfur in the black solid is melted by heating to form liquid sulfur. The temperature is preferably controlled at 110 to 150° C. to ensure that the sulfur melts but does not decompose. After passing through the liquefaction system, the suspension is passed through a filtration system for solid-liquid separation. A suitable filter medium (such as a filter cloth or filter mesh preferably with a pore size of 1 to 10 microns) is used to remove fixed carbon and other insoluble matter, so that the filtered liquid sulfur should be as pure as possible and have the lowest impurity content.

[0015] Preferably, in step 3, the filtered liquid sulfur is introduced into a condensation system to condense the liquid sulfur into solid sulfur. The cooling rate is controlled at 5 to 10° C. / minute to avoid uneven sulfur crystallization caused by rapid cooling. The final condensation temperature is preferably controlled at 30 to 50° C. to ensure complete solidification of the sulfur.

[0016] Preferably, in step three, the condensed high-quality sulfur is finally collected and then subjected to necessary testing to ensure that the sulfur product meets the quality standards.

[0017] In summary, the present invention mainly has the following beneficial effects:

[0018] This method dissolves soluble parts such as inorganic salts in water under hydrothermal conditions, converts the oil in low-quality sulfur paste into high-crystallization fixed carbon through a hydrothermal method, thereby changing the oil's solubility and boiling point. Soluble and insoluble matter in the sulfur paste are separated by filtration. The sulfur in the raw material is liquefied through a liquefaction system and separated from the fixed carbon and insoluble matter. The insoluble impurities in the liquid sulfur are removed through a filtration system, and finally high-quality sulfur is obtained through a condensation system. This method has a wide range of applications and can be used to purify low-quality sulfur with high oil content, solid content, and inorganic salt content. At the same time, the treatment process is simple, greatly reducing treatment costs, and is an effective way to recycle low-quality sulfur resources. The main raw materials are water and low-quality sulfur paste, and the site selection requirements are low and the site flexibility is strong. The main means are mainly heating and cooling, with a short process and simple operation, which is conducive to implementation and control in actual operation. At the same time, the reaction time and reaction temperature can be shortened and reduced by adding surfactants. Therefore, it can be used as a pretreatment unit coupled with sulfur melting processes, gasification processes, and extraction processes, and has a wide range of applications to achieve the effect of producing high-quality sulfur. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the method flow structure of the present invention;

[0020] Figure 2 It is the XRD spectrum of the sulfur paste before and after hydrothermal treatment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the described 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.

[0022] The following examples are intended to illustrate the present invention but are not intended to limit the scope of protection of the present invention. The conditions in the examples may be further adjusted according to specific conditions. Simple improvements to the method of the present invention within the scope of the present invention are also within the scope of protection claimed in the present invention.

[0023] refer to Figure 1-Figure 2 A method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste comprises the following steps:

[0024] Step 1: crush and sieve the low-quality sulfur paste, prepare a suspension of a certain concentration with the solvent according to the mass ratio, add a certain proportion of additives and stir for a certain time;

[0025] Step 2: Transfer the suspension obtained in step 1 into a reactor, raise the temperature to the reaction temperature for hydrothermal reaction, and obtain a black solid by hot filtration;

[0026] Step 3: The black solid is separated into solid and liquid by the liquefaction system, the fixed carbon and other insoluble substances are removed by the filtration system, and high-quality sulfur is obtained by the condensation system.

[0027] refer to Figure 1-Figure 2 The low-quality sulfur paste in step one refers to the high-oil sulfur paste produced in the process of removing H2S from raw coal gas using the direct oxidation method. The suspension solvent in step one is water and / or molten sulfur kettle water, and the preferred solvent is sulfur kettle water. The concentration of the sulfur paste in the suspension solvent is 10-80% (mass concentration), and the preferred concentration is 50% (mass ratio). The additive in the suspension is a macromolecular surfactant, and the preferred additive is polyvinyl pyrrolidone, with a concentration of 0-5%, and a preferred concentration of 0-0.05%.

[0028] refer to Figure 1-Figure 2 In the step 1, the suspension is stirred at a rate of 0 to 2000 rpm, preferably 600 rpm, and the stirring time is 0 to 60 minutes, preferably 30 minutes. In the step 2, the hydrothermal reaction reactor is a closed reactor with a stirring function. The stirring rate of the hydrothermal reaction is 0 to 1000 rpm, preferably 400 rpm, the temperature is 40 to 300°C, preferably 60 to 180°C, the time is 0 to 300 minutes, preferably 30 minutes, and the filtration temperature after the reaction is 30 to 100°C, preferably 60°C.

[0029] refer to Figure 1-Figure 2 In step 3, the black solid suspension is introduced into a liquefaction system, and the sulfur in the black solid is melted by heating to form liquid sulfur. The temperature is preferably controlled at 110-150° C. to ensure that the sulfur melts but does not decompose. After passing through the liquefaction system, the suspension is passed through a filtration system for solid-liquid separation. A suitable filter medium (such as a filter cloth or filter mesh preferably with a pore size of 1-10 microns) is used to remove fixed carbon and other insoluble matter, so that the filtered liquid sulfur should be as pure as possible and have the lowest impurity content.

[0030] refer to Figure 1-Figure 2 In step three, the filtered liquid sulfur is introduced into a condensation system to condense the liquid sulfur into solid sulfur. The cooling rate is controlled at 5-10°C / minute to avoid uneven sulfur crystallization caused by rapid cooling. The final condensation temperature is preferably controlled at 30-50°C to ensure that the sulfur is completely solidified. In step three, the high-quality condensed sulfur is finally collected and necessary testing is performed to ensure that the sulfur product meets the quality standards.

[0031] Example 1

[0032] 30 g of sulfur paste passed through a 40-mesh sieve was added to 100 g of tap water, and the mixture was stirred at 1000 rpm for 20 minutes to obtain a uniform suspension. The obtained solution was transferred to a 200 ml autoclave, heated to 180° C., and reacted for 3 hours at a stirring rate of 600 rpm. The solution was cooled to 80° C. and filtered while hot to obtain a black solid. The black solid was heated to 140° C. to obtain a liquid, which was then filtered and cooled to obtain yellow high-quality sulfur.

[0033] Example 2

[0034] 30 g and 0.3 g of sulfur paste passed through a 40-mesh sieve were added to 100 g of tap water, and the mixture was stirred at 1000 rpm for 20 minutes to obtain a uniform suspension. The obtained solution was transferred to a 200 ml autoclave and heated to 180° C. The mixture was reacted at a stirring rate of 600 rpm for 0.5 hours. The black solid was filtered while hot, and the black solid was heated to 140° C. to obtain a liquid, which was filtered and cooled to obtain yellow high-quality sulfur.

[0035] Example 3

[0036] 30 g of sulfur paste passed through a 40-mesh sieve and 0.3 g of PVP were added to 100 g of tap water, and the mixture was stirred at 1000 rpm for 20 minutes to obtain a uniform suspension. The obtained solution was transferred to a 200 ml autoclave and heated to 60° C. The mixture was reacted for 10 hours at a stirring rate of 600 rpm. The mixture was filtered while hot to obtain a black solid. The black solid was heated to 140° C. to obtain a liquid, which was filtered and cooled to obtain yellow high-quality sulfur.

[0037] Working principle: Please refer to Figure 1-Figure 2 As shown, this method dissolves soluble parts such as inorganic salts in water under hydrothermal conditions, converts the oil in the low-quality sulfur paste through the hydrothermal method into high-crystalline fixed carbon, thereby changing the oil's solubility and boiling point. The soluble matter in the sulfur paste is separated from the insoluble matter by filtration. The sulfur in the raw material is liquefied through a liquefaction system and separated from the fixed carbon and insoluble matter. The insoluble impurities in the liquid sulfur are removed through a filtration system, and finally high-quality sulfur is obtained through a condensation system. This method has a wide range of applications and can be used to purify low-quality sulfur with high oil content, solid content, and inorganic salt content. At the same time, the treatment process is simple, greatly reducing treatment costs, and is an effective way to recycle low-quality sulfur resources. Its main raw materials are water and low-quality sulfur paste, and the site selection requirements are low and flexible. The main means are mainly heating and cooling, with a short process and simple operation, which is conducive to implementation and control in actual operation. At the same time, the reaction time and reaction temperature can be shortened and lowered by adding surfactants. Therefore, it can be used as a pretreatment unit coupled with sulfur melting process, gasification process, and extraction process, with a wide range of applications to achieve the effect of producing high-quality sulfur.

[0038] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that, unless otherwise defined, the technical or scientific terms used in the present invention shall have the ordinary meanings understood by persons having ordinary skills in the field to which the present invention belongs. The words "include" or "comprise" and the like used in the present invention mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words "connect" or "connected" and the like are not limited to physical or mechanical connections, but may also include electrical connections, whether direct or indirect. The words "upper", "lower", "left", "right", etc. are only used to indicate relative position relationships. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

[0039] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste, characterized in that: The steps include: Step 1: crush and sieve the low-quality sulfur paste, prepare a suspension of a certain concentration with the solvent according to the mass ratio, add a certain proportion of additives and stir for a certain time; Step 2: Transfer the suspension obtained in step 1 into a reactor, raise the temperature to the reaction temperature for hydrothermal reaction, and obtain a black solid by hot filtration; Step 3: The black solid is separated into solid and liquid by the liquefaction system, the fixed carbon and other insoluble substances are removed by the filtration system, and high-quality sulfur is obtained by the condensation system.

2. The method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste according to claim 1, characterized in that: The low-quality sulfur paste in step 1 refers to the high-oil sulfur paste produced during the process of removing H2S from raw coal gas using a direct oxidation method.

3. The method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste according to claim 1, characterized in that: In the step 1, the suspension solvent is water and / or molten sulfur kettle water, preferably the solvent is sulfur kettle water, wherein the concentration of sulfur paste in the suspension solvent is 10-80% (mass concentration), preferably 50% (mass ratio), and the additive in the suspension is a macromolecular surfactant, preferably polyvinyl pyrrolidone, with a concentration of 0-5%, preferably 0-0.05%.

4. The method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste according to claim 1, characterized in that: In the step 1, the suspension is stirred at a rate of 0 to 2000 rpm, preferably 600 rpm, and for a time of 0 to 60 minutes, preferably 30 minutes.

5. The method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste according to claim 1, characterized in that: The hydrothermal reaction reactor in step 2 is a closed reactor with a stirring function. The stirring rate of the hydrothermal reaction is 0 to 1000 rpm, preferably 400 rpm, the temperature is 40 to 300°C, preferably 60 to 180°C, the time is 0 to 300 minutes, preferably 30 minutes, and the filtration temperature after the reaction is 30 to 100°C, preferably 60°C.

6. The method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste according to claim 1, characterized in that: In step 3, the black solid suspension is introduced into a liquefaction system, and the sulfur in the black solid is melted by heating to form liquid sulfur. The temperature is preferably controlled at 110-150° C. to ensure that the sulfur melts but does not decompose. After passing through the liquefaction system, the suspension is passed through a filtration system for solid-liquid separation. A suitable filter medium (such as a filter cloth or filter mesh preferably with a pore size of 1-10 microns) is used to remove fixed carbon and other insoluble matter, so that the filtered liquid sulfur should be as pure as possible and have the lowest impurity content.

7. The method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste according to claim 1, characterized in that: In the step 3, the filtered liquid sulfur is introduced into a condensation system to condense the liquid sulfur into solid sulfur. The cooling rate is controlled at 5 to 10° C. / minute to avoid uneven sulfur crystallization caused by rapid cooling. The final condensation temperature is preferably controlled at 30 to 50° C. to ensure that the sulfur is completely solidified.

8. The method for preparing high-quality sulfur by hydrothermal carbon fixation of low-quality sulfur paste according to claim 1, characterized in that: In step three, the condensed high-quality sulfur is finally collected and then subjected to necessary testing to ensure that the sulfur product meets the quality standards.

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