Salt extraction system for coking desulfurization waste liquid

Abstract

The utility model belongs to the field of industrial waste liquid treatment and recovery, disclose is a kind of coking desulfurization waste liquid salt extraction system, including pretreatment system and first salt extraction system;The pretreatment system includes first reaction kettle and first filter device, the first reaction kettle with the first filter device is connected, for the impurity removal and filtration of coking desulfurization waste liquid;The first salt extraction system includes crystallization reactor and second filter device, the crystallization reactor includes feed inlet, liquid discharge port and solid discharge port, the feed inlet is used to put in the coking desulfurization waste liquid after impurity removal and copper sulfate solution, the solid discharge port with the second filter device is connected, and the second filter device is used to filter out cuprous thiocyanate. Cuprous thiocyanate reaction precipitation can be realized to filtration treatment, and the processing efficiency is improved.

Description

Technical Field

[0001] This utility model belongs to the field of industrial waste liquid treatment and recycling, and in particular, it is a salt extraction system for coking desulfurization waste liquid. Background Technology

[0002] Desulfurization wastewater is the wastewater generated by coking plants during the treatment of water gas to remove acidic gases such as hydrogen sulfide and hydrogen cyanide. This wastewater contains large amounts of sodium thiocyanate, sodium thiosulfate, sodium sulfite, and sodium sulfate. Current treatment processes mainly include harmless treatment, salt separation and crystallization, and recovery of cuprous thiocyanate. The process for recovering cuprous thiocyanate involves reacting copper sulfate with reducing substances such as thiosulfate in the desulfurization wastewater to generate cuprous ions, which then combine with thiocyanate to form cuprous thiocyanate precipitate.

[0003] Most existing technologies employ intermittent reaction methods, either adding copper sulfate solution to the desulfurization waste liquid or vice versa. This approach not only results in poor crystallization performance and high water content in the product but also leads to low processing efficiency. Utility Model Content

[0004] The purpose of this invention is to improve the shortcomings of the existing technology and provide a salt extraction system for coking desulfurization waste liquid, which can realize the reaction precipitation of cuprous thiocyanate and filtration treatment, thereby improving the treatment efficiency.

[0005] The following technical solutions are used to achieve the above objectives.

[0006] A coking desulfurization wastewater salt extraction system includes a pretreatment system and a first salt extraction system. The pretreatment system includes a first reaction vessel and a first filtration device. The first reaction vessel is connected to the first filtration device and is used for removing impurities and filtering the coking desulfurization wastewater. The first salt extraction system includes a crystallization reactor and a second filtration device. The crystallization reactor includes an inlet, a liquid outlet, and a solid outlet. The inlet is used to feed the removed coking desulfurization wastewater and copper sulfate solution. The solid outlet is connected to the second filtration device, which is used to filter out cuprous thiocyanate.

[0007] In some embodiments, the coking desulfurization wastewater salt extraction system further includes a second salt extraction system, which includes a second reaction vessel, a third filtration device, an evaporator, and a centrifugal separator. The liquid discharge port is directly or indirectly connected to the inlet of the second reaction vessel, the outlet of the second reaction vessel is connected to the third filtration device, the third filtration device is connected to the evaporator, and the outlet of the evaporator is connected to the inlet of the centrifugal separator. The centrifugal separator is used to separate sodium sulfate.

[0008] In some embodiments, the second salt extraction system further includes a transfer tank, and the second reaction vessel, the third filtration device, the transfer tank and the evaporator are connected in sequence.

[0009] In some embodiments, the second salt extraction system further includes a condensing device and a mother liquor tank, the condensing device being connected to the evaporation port of the evaporator and the mother liquor tank being connected to the liquid outlet of the centrifuge.

[0010] In some embodiments, the first salt extraction system further includes a washing device, a washing liquid tank, and a fourth filtration device, wherein the outlet of the washing liquid tank is connected to the washing device, the outlet of the washing device is connected to the fourth filtration device, and the fourth filtration device is used to filter out the washed cuprous thiocyanate.

[0011] In some embodiments, the first salt extraction system further includes a liquid storage device, wherein the liquid discharge port, the liquid outlet of the second filter device, and the liquid outlet of the fourth filter device are all connected to the liquid inlet of the liquid storage device, and the liquid outlet of the liquid storage device is connected to the second reaction vessel.

[0012] In some embodiments, the pretreatment system further includes a homogenizing tank and a purification liquid tank, the homogenizing tank being connected to the first reaction vessel, the inlet of the purification liquid tank being connected to the outlet of the first filtration device, and the outlet of the purification liquid tank being connected to the feed inlet.

[0013] In some embodiments, the first salt extraction system further includes a copper sulfate batching device connected to the inlet.

[0014] In some embodiments, the crystallization reactor further includes a stirring device, an inner partition, and an outer partition. A first space is formed inside the inner partition, and a second space is formed between the inner partition and the outer partition. The bottom of the first space communicates with the second space. The feed inlet communicates with the first space, the stirring part of the stirring device is located in the first space, the liquid discharge outlet communicates with the second space, and the solid discharge outlet is located at the bottom of the second space.

[0015] In some embodiments, the crystallization reactor further includes an additional layer installed outside the outer partition layer, forming a third space between the additional layer and the outer partition layer. The additional layer has a first liquid port located at the bottom and a second liquid port located at the top, both of which communicate with the third space.

[0016] The technical solution provided by this utility model has the following advantages and effects:

[0017] During salt extraction, the coking desulfurization wastewater is introduced into the first reaction vessel. Activated carbon is added to the reaction vessel to adsorb and remove suspended sulfur and solid particles. The wastewater is then introduced into the first filtration device for solid-liquid separation. The pre-treated wastewater is then introduced into a crystallization reactor, along with a copper sulfate solution. After continuous reaction, the precipitated cuprous thiocyanate is discharged through the solids outlet into the second filtration device for dehydration, yielding relatively dry cuprous thiocyanate. The entire process is continuous, effectively introducing the coking desulfurization wastewater into the production of cuprous thiocyanate, thus improving treatment efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0019] Figure 2 This is a schematic diagram of the crystallization reactor structure according to an embodiment of the present invention;

[0020] Explanation of reference numerals in the attached figures:

[0021] 100. Pretreatment system; 101. Homogenizing tank; 102. First reaction vessel; 103. First filtration device; 104. Purified liquid tank; 200. First salt extraction system; 201. Crystallization reactor; 202. Copper sulfate batching device; 203. Storage device; 204. Transfer tank; 205. Second filtration device; 206. Washing device; 207. Washing liquid tank; 208. Fourth filtration device; 300. Second salt extraction system; 301. Second reaction vessel; 302. 303. Third filtration device; 304. Transfer tank; 305. Evaporator; 306. Condensation device; 307. Centrifuge; 308. Mother liquor tank; 41. Inner partition; 42. Outer partition; 43. Feed inlet; 44. Liquid discharge outlet; 45. Solid discharge outlet; 46. Additional layer; 461. First liquid outlet; 462. Second liquid outlet; 47. Variable frequency reducer; 48. Drive shaft; 49. Stirring blade; 51. First space; 52. Second space; 53. Third space. Detailed Implementation

[0022] To facilitate understanding of this utility model, the specific embodiments of this utility model will be described in more detail below with reference to the accompanying drawings.

[0023] Unless otherwise specified or defined, the terms "first," "second," etc., used in this document are for distinguishing names only and do not represent a specific number or order.

[0024] Unless otherwise stated or defined, the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0025] It should be noted that when a component is considered to be "fixed" to another component, it can be directly fixed to the other component or there can be an intermediate component.

[0026] like Figure 1 and Figure 2 As shown, the coking desulfurization wastewater salt extraction system includes a pretreatment system 100 and a first salt extraction system 200. The pretreatment system 100 includes a first reaction vessel 102 and a first filter device 103. The first reaction vessel 102 is connected to the first filter device 103 and is used for removing impurities and filtering the coking desulfurization wastewater. The first salt extraction system 200 includes a crystallization reactor 201 and a second filter device 205. The crystallization reactor 201 includes an inlet 43, a liquid outlet 44, and a solid outlet 45. The inlet 43 is used to feed the removed coking desulfurization wastewater and copper sulfate solution. The solid outlet 45 is connected to the second filter device 205, which is used to filter out cuprous thiocyanate.

[0027] During salt extraction, the coking desulfurization wastewater is introduced into the first reaction vessel 102. Activated carbon is added to the first reaction vessel 102 to remove suspended sulfur and solid particles through adsorption. Then, the coking desulfurization wastewater in the first reaction vessel 102 is introduced into the first filtration device 103 for solid-liquid separation. The pre-removed coking desulfurization wastewater is then introduced into the crystallization reactor 201, along with a copper sulfate solution. After continuous reaction, the precipitated cuprous thiocyanate is introduced into the second filtration device 205 through the solid discharge port 45 to dehydrate the cuprous thiocyanate, yielding a relatively dry crude cuprous thiocyanate. The entire process is continuous, achieving the goal of introducing coking desulfurization wastewater directly into the production of cuprous thiocyanate, thereby improving treatment efficiency.

[0028] See Figure 1 As shown, a transfer tank 204 is also provided between the crystallization reactor 201 and the second filter device 205. The transfer tank 204 is used to connect the crystallization reactor 201 and the second filter device 205.

[0029] See Figure 1As shown, the coking desulfurization wastewater salt extraction system also includes a second salt extraction system 300. The second salt extraction system 300 includes a second reaction vessel 301, a third filter device 302, an evaporator 304, and a centrifuge 306. The liquid discharge port 44 is directly or indirectly connected to the inlet of the second reaction vessel 301. The outlet of the second reaction vessel 301 is connected to the third filter device 302. The third filter device 302 is connected to the evaporator 304. The outlet of the evaporator 304 is connected to the inlet of the centrifuge 306. The centrifuge 306 is used to separate sodium sulfate, i.e., the sodium sulfate product. The second salt extraction system 300 also includes a transfer tank 303. The second reaction vessel 301, the third filter device 302, the transfer tank 303, and the evaporator 304 are connected sequentially.

[0030] The remaining liquid after the reaction in crystallization reactor 201 still contains dissolved sodium sulfate, so a second salt extraction system 300 is set up for recovering sodium sulfate. The remaining liquid after the reaction in crystallization reactor 201 is introduced into a second reaction vessel 301. An oxidant and a heavy metal scavenger are added to the second reaction vessel 301 for oxidation and impurity removal, oxidizing reducing substances such as sodium tetrathionate to sodium sulfate and removing heavy metals. The oxidized and impurity-removed liquid is then filtered through a third filtration device 302 and introduced into an evaporator 304 for evaporation and crystallization. Finally, the crystallized solid-liquid mixture is introduced into a centrifuge 306 to separate the sodium sulfate, thus recovering sodium sulfate. The entire process is continuous, thus improving the efficiency of sodium sulfate extraction. This setup creates a complete process route for sodium sulfate extraction. It should be noted that the transfer tank 303 can be connected to the third filter device 302 and the evaporator 304 simultaneously or not simultaneously. That is, the transfer tank 303 can be disconnected from the third filter device 302 before being connected to the evaporator 304.

[0031] See Figure 1 As shown, the second salt extraction system 300 also includes a condenser 305 and a mother liquor tank 307. The condenser 305 is connected to the evaporation port of the evaporator 304, and the mother liquor tank 307 is connected to the liquid outlet of the centrifuge 306. The condenser 305 is used to condense the gas evaporated from the evaporator 304, and the mother liquor tank 307 collects the liquid after centrifugation.

[0032] See also Figure 1As shown, to obtain cuprous thiocyanate with a lower impurity content, the first salt extraction system 200 further includes a washing device 206, a washing liquid tank 207, and a fourth filtration device 208. The outlet of the washing liquid tank 207 is connected to the washing device 206, and the outlet of the washing device 206 is connected to the fourth filtration device 208. The fourth filtration device 208 is used to filter out the washed cuprous thiocyanate. The washing device 206 washes the cuprous thiocyanate filtered by the second filtration device 205, and the washing liquid tank 207 can be filled with hot water for washing. The washed cuprous thiocyanate is then filtered by the fourth filtration device 208 to obtain cuprous thiocyanate with a lower impurity content, i.e., the cuprous thiocyanate product.

[0033] See Figure 1 As shown, the first salt extraction system 200 also includes a liquid storage device 203. The liquid discharge port 44, the outlet of the second filter device 205, and the outlet of the fourth filter device 208 are all connected to the inlet of the liquid storage device 203. The outlet of the liquid storage device 203 is connected to the second reaction vessel 301. That is, in the first salt extraction system 200, the liquid discharged from the crystallization reactor 201, and the liquid filtered by the second filter device 205 and the third filter device 302 are collected in the liquid storage device 203, ensuring no liquid loss, i.e., no loss of sodium sulfate solution, throughout the entire process. In the second salt extraction system 300, the liquid collected in the mother liquor tank 307 can be further introduced into the storage device for continued sodium sulfate extraction. This process continues until a certain number of cycles are completed before the liquid in the mother liquor tank 307 is processed.

[0034] The first salt extraction system 200 further includes a copper sulfate batching device 202, which is connected to the feed inlet 43. The copper sulfate batching device 202 is used to dissolve copper sulfate. The copper sulfate batching device 202 contains a copper sulfate solution, and a metering pump pumps the copper sulfate and pretreated coking desulfurization wastewater into the feed inlet 43 in a certain proportion.

[0035] See Figure 1 As shown, the pretreatment system 100 further includes a homogenization tank 101 and a purified liquid tank 104. The homogenization tank 101 is connected to the first reaction vessel 102, the inlet of the purified liquid tank 104 is connected to the outlet of the first filter device 103, and the outlet of the purified liquid tank 104 is connected to the feed inlet 43. Before treating the coking desulfurization wastewater, it first passes through the homogenization tank 101 to ensure that the component content of the coking desulfurization wastewater to be treated does not fluctuate significantly, which is beneficial for subsequent salt extraction. In addition, the purified liquid tank 104 can store the coking desulfurization wastewater that has been treated by the pretreatment system 100, awaiting the next step of salt extraction.

[0036] See Figure 2As shown, the crystallization reactor 201 further includes a stirring device, an inner partition 41, and an outer partition 42. A first space 51 is formed inside the inner partition 41, and a second space 52 is formed between the inner partition 41 and the outer partition 42. The bottom of the first space 51 communicates with the second space 52. The feed inlet 43 communicates with the first space 51. The stirring part of the stirring device is located in the first space 51. The liquid discharge outlet 44 communicates with the second space 52. The solid discharge outlet 45 is located at the bottom of the second space 52.

[0037] The pretreated coking desulfurization waste liquid and copper sulfate solution are introduced into the first space 51 of the crystallization reactor 201. Stirring is used to ensure thorough contact and reaction between the coking desulfurization waste liquid and the copper sulfate solution, producing cuprous thiocyanate. Meanwhile, coking desulfurization waste liquid and copper sulfate solution are continuously introduced into the first space 51, causing the liquid to flow from the first space 51 to the second space 52, and then discharged through the liquid discharge port 44. Since cuprous thiocyanate is a solid, it gradually settles at the bottom of the second space 52, and can be discharged through the solid discharge port 45.

[0038] See Figure 2 As shown, the stirring device includes a frequency converter 47, a drive shaft 48, and a stirring blade 49. The frequency converter 47 is installed outside the first space 51 and extends into the first space 51 through the drive shaft 48, and is connected to the stirring blade 49 to drive the stirring blade 49.

[0039] A discharge valve is installed at the solid discharge port 45 to control its opening and closing. The feed port 43 is located at the upper part of the first space 51, while the liquid discharge port 44 is located at the upper part of the second space 52. The liquid flows from the upper part to the bottom of the first space 51 and then from the bottom to the top of the second space 52, which promotes a full reaction and facilitates the precipitation of cuprous thiocyanate.

[0040] See Figure 2As shown, the crystallization reactor 201 further includes an additional layer 46, which is installed outside the outer partition layer 42. A third space 53 is formed between the additional layer 46 and the outer partition layer 42. The additional layer 46 has a first liquid port 461 at the bottom and a second liquid port 462 at the top, both of which communicate with the third space 53. The third space 53 covers the outside of the second space 52. By injecting hot liquid into the third space 53, the reaction within the second space 52 can be promoted, facilitating the complete production of cuprous thiocyanate. Specifically, hot liquid is injected through the first liquid port 461 and flows out through the second liquid port 462, ensuring a longer flow path for the hot liquid. The hot liquid can be the liquid within the condenser 305, thus fully utilizing the heat of the entire salt extraction system.

[0041] It should be noted that the first filter device 103, the second filter device 205, the third filter device 302 and the fourth filter device 208 here are all filter presses, which can improve filtration efficiency through pressure.

[0042] The waste activated carbon filtered out by the first filter device 103 and the purified residue filtered out by the third filter device 302 are both sent to a qualified facility for disposal, thus making the entire salt extraction project more environmentally friendly.

[0043] Connections can be direct or indirect, and can be made through pipes or other devices. When referring to drawings, new features are described. To avoid redundant references to drawings that would make the description less concise, features already described will not be referenced again on the drawings if the description is clear.

[0044] The above embodiments are not an exhaustive list based on the present invention, and there may be other embodiments not listed. Any substitutions and improvements made without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A salt extraction system for coking desulfurization wastewater, characterized in that, Includes a pretreatment system and a first salt extraction system; The pretreatment system includes a first reaction vessel and a first filtration device. The first reaction vessel is connected to the first filtration device and is used to remove impurities and filter coking desulfurization wastewater. The first salt extraction system includes a crystallization reactor and a second filtration device. The crystallization reactor includes a feed inlet, a liquid outlet, and a solid outlet. The feed inlet is used to introduce the desulfurized coking waste liquid and copper sulfate solution after impurity removal. The solid outlet is connected to the second filtration device, which is used to filter out cuprous thiocyanate.

2. The coking desulfurization wastewater salt extraction system as described in claim 1, characterized in that, It also includes a second salt extraction system, which includes a second reaction vessel, a third filtration device, an evaporator, and a centrifuge. The liquid discharge port is directly or indirectly connected to the inlet of the second reaction vessel, the outlet of the second reaction vessel is connected to the third filtration device, the third filtration device is connected to the evaporator, the outlet of the evaporator is connected to the inlet of the centrifuge, and the centrifuge is used to separate sodium sulfate.

3. The coking desulfurization wastewater salt extraction system as described in claim 2, characterized in that, The second salt extraction system also includes a transfer tank, and the second reaction vessel, the third filtration device, the transfer tank and the evaporator are connected in sequence.

4. The coking desulfurization wastewater salt extraction system as described in claim 3, characterized in that, The second salt extraction system also includes a condensing device and a mother liquor tank. The condensing device is connected to the evaporation port of the evaporator, and the mother liquor tank is connected to the liquid outlet of the centrifuge.

5. The coking desulfurization wastewater salt extraction system as described in claim 2, characterized in that, The first salt extraction system also includes a washing device, a washing liquid tank, and a fourth filtration device. The outlet of the washing liquid tank is connected to the washing device, and the outlet of the washing device is connected to the fourth filtration device. The fourth filtration device is used to filter out the washed cuprous thiocyanate.

6. The coking desulfurization wastewater salt extraction system as described in claim 5, characterized in that, The first salt extraction system also includes a liquid storage device. The liquid discharge port, the liquid outlet of the second filter device, and the liquid outlet of the fourth filter device are all connected to the liquid inlet of the liquid storage device. The liquid outlet of the liquid storage device is connected to the second reaction vessel.

7. The coking desulfurization wastewater salt extraction system according to any one of claims 1 to 6, characterized in that, The pretreatment system further includes a homogenization tank and a purification liquid tank. The homogenization tank is connected to the first reaction vessel, the inlet of the purification liquid tank is connected to the outlet of the first filtration device, and the outlet of the purification liquid tank is connected to the feed inlet.

8. The coking desulfurization wastewater salt extraction system according to any one of claims 1 to 6, characterized in that, The first salt extraction system also includes a copper sulfate batching device, which is connected to the feed inlet.

9. The coking desulfurization wastewater salt extraction system according to any one of claims 1 to 6, characterized in that, The crystallization reactor further includes a stirring device, an inner partition, and an outer partition. A first space is formed inside the inner partition, and a second space is formed between the inner partition and the outer partition. The bottom of the first space communicates with the second space. The feed inlet is connected to the first space, the stirring part of the stirring device is located in the first space, the liquid discharge outlet is connected to the second space, and the solid discharge outlet is located at the bottom of the second space.

10. The coking desulfurization wastewater salt extraction system as described in claim 9, characterized in that, The crystallization reactor further includes an additional layer, which is installed outside the outer partition layer. A third space is formed between the additional layer and the outer partition layer. The additional layer has a first liquid port located at the bottom and a second liquid port located at the top. Both the first liquid port and the second liquid port communicate with the third space.

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