Sulfur foam gradient centrifugation-microwave drying synergistic concentration method

Abstract

The invention belongs to the technical field of sulfur foam separation, and particularly relates to a sulfur foam gradient centrifugation-microwave drying synergistic concentration method. According to the sulfur foam gradient centrifugation-microwave drying synergistic concentration method disclosed by the invention, the sulfur foam is modified by utilizing the selected foam modifier, so that bubbles of the sulfur foam can be effectively reduced, the viscosity performance of feed liquid can be reduced, and bubbles and sulfur particles in the sulfur foam can be effectively destroyed to form a colloid system; the separation of water in the sulfur foam is promoted, and the dehydration effect is further enhanced, so that the treated sulfur foam can realize dehydration and drying treatment on the high-water-content sulfur foam only through conventional physical dehydration treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of sulfur foam separation, and particularly relates to a sulfur foam gradient centrifugation-microwave drying synergistic concentration method. Background Art

[0002] During the wet desulfurization and regeneration process of coke oven gas, flotation produces a large amount of sulfur foam. This foam's concentration varies widely, and its high liquid content hinders subsequent processing. Furthermore, the sulfur foam produced during wet desulfurization of coke oven gas can be used to produce sulfuric acid, effectively recycling sulfur resources while addressing issues such as the discharge of salt-containing wastewater during the desulfurization process and reducing environmental pollution. This represents a promising development direction in the field of coking desulfurization. Currently, pretreatment of the sulfur foam during this process—effectively concentrating and separating it—is a prerequisite for the subsequent incineration of acid production feedstock to produce acid production gas.

[0003] Sulfur foam concentration refers to the process of increasing the sulfur content of sulfur foam during the sulfur recovery process through specific methods, allowing for more efficient recovery and processing. Currently, sulfur foam is typically treated using plate and frame filter pressing and centrifugal separation, or directly incinerated in an incinerator to produce acid. The purpose of plate and frame filter pressing is to filter out sulfur particles from the sulfur foam and compress them into a sulfur paste for sulfur production. The clear liquid after filter pressing is used for desulfurization and is generally returned to the reaction tank of the desulfurization system. The desulfurization liquid from the desulfurization tower is continuously circulated in the desulfurization tower through a circulating pump in countercurrent contact with the coal gas for desulfurization. Centrifugal separation uses a centrifuge, which passes the separated sulfur particles into a filter press or sulfur melting kettle. The clear liquid after centrifugation returns to the desulfurization tower.

[0004] It can be seen that sulfur foam concentration is a key step in the sulfur recovery process. Through physical, chemical and thermal methods, the sulfur content in the sulfur foam can be increased, the recovery efficiency can be optimized, the impurity content can be reduced, and the efficiency and safety of the process can be ensured. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a sulfur foam gradient centrifugation-microwave drying synergistic concentration method, which can effectively solve the problem that the sulfur foam has a high viscosity and high water content that affects the drying effect of the dehydrating agent.

[0006] The present invention provides a sulfur foam gradient centrifugation-microwave drying synergistic concentration method, comprising the following steps: (1) Adding a foam modifier to the sulfur foam to be treated, stirring and mixing, and obtaining a sulfur foam liquid; (2) filtering the sulfur foam liquid to perform a first solid-liquid separation to remove part of the water; (3) continuing to centrifuge the sulfur foam liquid for a second solid-liquid separation to continue removing water; (4) Collect the solid part and perform microwave drying.

[0007] In some preferred embodiments, in step (2), the first solid-liquid separation step comprises gravity sedimentation or plate and frame filtration.

[0008] In some preferred embodiments, in step (3), the centrifugal speed of the second solid-liquid separation step is 5000-8000 rpm.

[0009] In some preferred embodiments, in step (4), the microwave frequency of the microwave drying step is 900-1200 MHz.

[0010] In some preferred embodiments, in step (1), the rotation speed of the stirring step is 200-400 rpm.

[0011] In some preferred embodiments, the foam modifier comprises an ionic liquid demulsifier.

[0012] In some preferred embodiments, the foam modifier comprises a betaine salt.

[0013] In some preferred embodiments, the foam modifier includes 1-ethyl-3-methylimidazolium betaine salt [EMIM][Betaine].

[0014] In some preferred embodiments, the foam modifier is added in an amount of 5-10 wt % based on the sulfur foam liquid.

[0015] In some preferred embodiments, the foam modifier further comprises esterase microcapsules.

[0016] The embodiments of the present invention have the following technical effects: The sulfur foam gradient centrifugation-microwave drying synergistic concentration method of the present invention utilizes a selected foam modifier to modify the sulfur foam, which can not only effectively reduce bubbles in the sulfur foam and reduce the viscosity of the feed liquid, but also effectively destroy the bubbles and sulfur particles in the sulfur foam to form a colloidal system, promote the separation of water in the sulfur foam, and further enhance the dehydration effect, so that the treated sulfur foam only requires conventional physical dehydration treatment to achieve dehydration and drying of the high-water-content sulfur foam.

[0017] The sulfur foam gradient centrifugation-microwave drying synergistic concentration method of the present invention uses 1-ethyl-3-methylimidazolium betaine salt [EMIM][Betaine] to modify the sulfur foam. Compared with general betaine salts or 1-ethyl-3-methylimidazolium salts, the sulfur foam has a better modification effect and is particularly suitable for the modification treatment of sulfur foam. It can effectively improve the foam and viscosity of the sulfur foam itself, is more conducive to the filtration step, and can destroy the colloidal structure between sulfur particles, reduce the influence of polymerized water, effectively improve the concentration and dehydration effects, and can solve the current problem of difficulty in dehydrating sulfur foam. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are considered to be within the scope of the present invention.

[0019] In the following embodiment of the present invention, a sulfur foam gradient centrifugation-microwave drying synergistic concentration method is provided, which specifically comprises the following steps: (1) Adding a foam modifier to the sulfur foam to be treated, stirring and mixing, and obtaining a sulfur foam liquid; (2) filtering the sulfur foam liquid to perform a first solid-liquid separation to remove part of the water; (3) continuing to centrifuge the sulfur foam liquid for a second solid-liquid separation to continue removing water; (4) Collect the solid part and perform microwave drying to obtain the product.

[0020] The sulfur foam gradient centrifugation-microwave drying synergistic concentration method of the present invention utilizes a selected foam modifier to modify the sulfur foam, which can not only effectively reduce bubbles in the sulfur foam and reduce the viscosity of the feed liquid, but also effectively destroy the bubbles and sulfur particles in the sulfur foam to form a colloidal system, promote the separation of water in the sulfur foam, and further enhance the dehydration effect, so that the treated sulfur foam only requires conventional physical dehydration treatment to achieve dehydration and drying of the high-water-content sulfur foam.

[0021] In some feasible implementation schemes, in step (2), the first solid-liquid separation step adopts a general physical filtration method, such as gravity sedimentation or plate and frame filter press.

[0022] In some feasible implementation schemes, in step (3), the second solid-liquid separation step adopts a general centrifugal filtration method, for example, controlling the centrifugal speed to 5000-8000 rpm.

[0023] In some feasible embodiments, in step (4), the microwave frequency of the microwave drying step is 900-1200 MHz.

[0024] In some feasible embodiments, in step (1), the rotation speed of the stirring step is 200-400 rpm, so that the foam modifier and the sulfur foam are in better contact, thereby achieving sufficient modification treatment.

[0025] In some possible embodiments, the foam modifier comprises an ionic liquid demulsifier.

[0026] In some possible embodiments, the foam modifier includes a betaine salt.

[0027] In some possible embodiments, the foam modifier includes 1-ethyl-3-methylimidazolium betaine salt [EMIM][Betaine].

[0028] In some feasible embodiments, the foam modifier is added in an amount of 5-10 wt % based on the sulfur foam liquid. When the addition amount is low, the modification effect is not ideal, and when the addition amount is high, the enhanced improvement effect is not obvious.

[0029] In some feasible embodiments, the foam modifier further includes esterase microcapsules. The esterase microcapsules can be prepared using conventional microencapsulation methods in the art. The selection of wall materials and other systems has little effect on the esterase modification effect. Those skilled in the art can make reasonable choices based on the concentration and other properties of the sulfur foam.

[0030] In the following embodiments of the present invention, the foam modifier is 1-ethyl-3-methylimidazolium betaine salt [EMIM][Betaine] as an example for foam modification treatment. The 1-ethyl-3-methylimidazolium betaine salt is an ionic liquid known in the art, and a commercial product can be selected or synthesized according to conventional methods.

[0031] In the following embodiments of the present invention, sulfur foam produced in the wet desulfurization process of coke oven gas is taken as an example. The sulfur foam contains sulfur particles, salt and other components. After testing, its water content reaches 65% and its viscosity reaches 198.43cp.

[0032] Example 1

[0033] Take the sulfur foam, add 8 wt % of 1-ethyl-3-methylimidazolium betaine salt [EMIM] [Betaine] and mix thoroughly, and stir thoroughly at 300 rpm for 10 minutes to obtain a foam mixture liquid.

[0034] The foam mixture liquid is placed in a plate and frame filter press for filtration, and the first filtrate is collected.

[0035] The filter cake was centrifuged at 6000 rpm for 10 min to collect the second filtrate; The second filtrate was placed in a microwave dryer and microwave dried at 1000 MHz for 1 h to obtain a dry product.

[0036] Example 2

[0037] Take the sulfur foam, add 5 wt % of 1-ethyl-3-methylimidazolium betaine salt [EMIM] [Betaine] and mix thoroughly, and stir thoroughly at 400 rpm for 10 minutes to obtain a foam mixture liquid.

[0038] The foam mixture liquid is placed in a plate and frame filter press for filtration, and the first filtrate is collected.

[0039] The filter cake was centrifuged at 8000 rpm for 10 min to collect the second filtrate; The second filtered product was placed in a microwave dryer and microwave dried at 1200 MHz for 1 hour to obtain the product.

[0040] Example 3

[0041] The sulfur foam was taken, 10 wt % of 1-ethyl-3-methylimidazolium betaine salt [EMIM] [Betaine] was added and fully mixed, and the mixture was fully stirred at a speed of 200 rpm for 10 minutes to obtain a foam mixed liquid.

[0042] The foam mixture liquid is placed in a plate and frame filter press for filtration, and the first filtrate is collected.

[0043] The filter cake was centrifuged at 5000 rpm for 10 min to collect the second filtrate; The second filtered product was placed in a microwave dryer and microwave dried at 900 MHz for 1 hour to obtain the product.

[0044] Example 4

[0045] The sulfur foam was taken, 3 wt % of 1-ethyl-3-methylimidazolium betaine salt [EMIM] [Betaine] was added and fully mixed, and the mixture was fully stirred at a speed of 300 rpm for 10 minutes to obtain a foam mixed liquid.

[0046] The foam mixture liquid is placed in a plate and frame filter press for filtration, and the first filtrate is collected.

[0047] The filter cake was centrifuged at 6000 rpm for 10 min to collect the second filtrate; The second filtered product was placed in a microwave dryer and microwave dried at 1000 MHz for 1 hour to obtain the product.

[0048] Example 5

[0049] The sulfur foam was taken, 12 wt % of 1-ethyl-3-methylimidazolium betaine salt [EMIM] [Betaine] was added and fully mixed, and the mixture was fully stirred at a speed of 300 rpm for 10 minutes to obtain a foam mixed liquid.

[0050] The foam mixture liquid is placed in a plate and frame filter press for filtration, and the first filtrate is collected.

[0051] The filter cake was centrifuged at 6000 rpm for 10 min to collect the second filtrate; The second filtered product was placed in a microwave dryer and microwave dried at 1000 MHz for 1 hour to obtain the product.

[0052] Example 6

[0053] Take the sulfur foam, add 8 wt % of 1-ethyl-3-methylimidazolium betaine salt [EMIM] [Betaine] and 5 wt % of esterase microcapsules, mix well, and stir well at 300 rpm for 10 minutes to obtain a foam mixture liquid.

[0054] The foam mixture liquid is placed in a plate and frame filter press for filtration, and the first filtrate is collected.

[0055] The filter cake was centrifuged at 6000 rpm for 10 min to collect the second filtrate; The second filtered product was placed in a microwave dryer and microwave dried at 1000 MHz for 1 hour to obtain the product.

[0056] Comparative Example 1 The method for treating the sulfur foam in this comparative example is the same as that in Example 1, except that betaine chloride is used as the foam modifier.

[0057] Comparative Example 2 The treatment method of the sulfur foam in this comparative example is the same as that in Example 1, the only difference being that betaine sulfate is selected as the foam modifier.

[0058] Comparative Example 3 The method for treating the sulfur foam in this comparative example is the same as that in Example 1, except that 1-ethyl-3-methylimidazolium chloride is selected as the foam modifier.

[0059] Comparative Example 4 The treatment method of the sulfur foam in this comparative example is the same as that in Example 1, except that 1-ethyl-3-methylimidazolium hexafluorophosphate is selected as the foam modifier.

[0060] Comparative Example 5 The treatment method of the sulfur foam in this comparative example is the same as that in Example 1, except that the sulfur foam is not subjected to modification treatment.

[0061] Experimental example

[0062] The foam mixture liquid collected in the above Example 1 and Comparative Examples 1-5 was respectively taken for viscosity monitoring, and the first filtrate and the second filtrate were taken for moisture content testing. The specific test results are shown in Table 1 below.

[0063] The initial viscosity of the sulfur foam to be treated is 198.43 cp, and the water content is 65%.

[0064] Table 1

[0065] It can be seen that the sulfur foam gradient centrifugation-microwave drying synergistic concentration method described in the present invention, after treating the sulfur foam with a selected foam modifier, can effectively improve the foam and viscosity of the sulfur foam itself, is more conducive to the filtration step, and can destroy the colloidal structure between the sulfur particles, reduce the influence of polymerized water, effectively improve the concentration and dehydration effects, and can solve the current problem of difficulty in dehydrating sulfur foam.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A sulfur foam gradient centrifugation-microwave drying synergistic concentration method, characterized in that: The steps include: (1) Adding a foam modifier to the sulfur foam to be treated, stirring and mixing, and obtaining a sulfur foam liquid; (2) filtering the sulfur foam liquid to perform a first solid-liquid separation to remove part of the water; (3) continuing to centrifuge the sulfur foam liquid for a second solid-liquid separation to continue removing water; (4) Collect the solid part and perform microwave drying.

2. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to claim 1, characterized in that: In the step (2), the first solid-liquid separation step includes gravity sedimentation or plate and frame filter press.

3. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to claim 2, characterized in that: In the step (3), the centrifugal speed of the second solid-liquid separation step is 5000-8000 rpm.

4. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to claim 3, characterized in that: In the step (4), the microwave frequency of the microwave drying step is 900-1200 MHz.

5. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to claim 4, characterized in that: In the step (1), the rotation speed of the stirring step is 200-400 rpm.

6. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to any one of claims 1 to 5, characterized in that: The foam modifier includes an ionic liquid demulsifier.

7. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to claim 6, characterized in that: The foam modifier includes a betaine salt.

8. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to claim 7, characterized in that: The foam modifier includes 1-ethyl-3-methylimidazolium betaine salt [EMIM] [Betaine].

9. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to any one of claims 1 to 5, characterized in that: The foam modifier is added in an amount of 5-10 wt % based on the sulfur foam liquid.

10. The sulfur foam gradient centrifugation-microwave drying synergistic concentration method according to any one of claims 1 to 5, characterized in that: The foam modifier also includes esterase microcapsules.

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