Device for optimizing co-production of acid and ammonium thiocyanate from desulfurization waste liquid

Abstract

The utility model relates to a device for optimizing co-production of acid and ammonium thiocyanate from desulfurization waste liquid. The device comprises a tank body and a cover body, a jacket is arranged on the outer wall of the tank body, a cooling cavity is formed between the jacket and the outer wall of the tank body, a medium inlet and a medium outlet are formed in the jacket, and the medium inlet and the medium outlet are both communicated with the cooling cavity; a filter plate is arranged in the tank body; an ammonium thiocyanate mother liquor outlet and a sulfo-impurity discharge hole are formed in the lower part of the side wall of the tank body; and the cover body is provided with a sulfur-containing concentrated solution inlet and a backwashing solution inlet. The device is not provided with an incineration structure and procedure, the problem that high-added-value ammonium thiocyanate is incinerated in the existing process of preparing acid from desulfurization foam and desulfurization waste liquid is solved, the problem that nitric oxide is too high in the acid preparation incineration process is solved, and therefore the problem that the content of nitrate in finished acid is too high is solved; according to the device, the process of preparing ammonium thiocyanate from the sulfur-containing concentrated solution and the process of preparing the sulfur-containing waste solution for acid making are integrated through the device, so that the process energy consumption is reduced, and the resources and the cost are saved.

Description

Technical Field

[0001] The utility model relates to the field of desulfurization waste liquid recovery, in particular to a device for optimizing the co-production of acid production and ammonium thiocyanate from desulfurization waste liquid. Background Art

[0002] At present, there are two main directions in the treatment of desulfurization foam and desulfurization waste liquid in the pre-ammonium desulfurization of sulfur-containing concentrated liquid in domestic coking enterprises: one is to make acid from desulfurization foam and desulfurization waste liquid; the other is to extract salt from desulfurization waste liquid and melt sulfur from desulfurization foam.

[0003] There are two major problems faced by desulfurization foam and desulfurization waste liquid acid production technology. First, the high-value-added product ammonium thiocyanate present in the desulfurization waste liquid is sent to the incinerator for incineration to produce sulfur-containing furnace gas after concentration or crystallization, and is not effectively recovered; second, the presence of ammonium thiocyanate produces a large amount of nitrogen oxides during the incineration process, which seriously affects the stable operation of the subsequent acid production section and causes the nitrate content in the finished acid production to exceed the standard, affecting product quality.

[0004] At present, there are three problems in extracting salt from desulfurization waste liquid. First, the energy consumption is high. The salt extraction process requires evaporation and concentration under vacuum conditions, which consumes huge amounts of electricity and steam. Second, the by-products are of poor quality and difficult to sell. Since the by-products ammonium thiosulfate and ammonium sulfate contain high levels of ammonium thiocyanate that cannot be removed, they cannot be sold in the market and are basically solid waste, which is either piled up or treated at a price. Third, there is a strong odor on site. Since the decolorization and unloading process of the decolorization kettle and the ammonium thiosulfate plate and frame filter press process are both open systems, the materials contain high ammonia, which leads to a strong odor on site.

[0005] Therefore, how to establish a co-production device to purify the ammonium thiocyanate product while using the ammonium thiosulfate produced in the ammonium thiocyanate production process as a miscellaneous salt to prepare it as a raw material for acid production has become an urgent problem to be solved. Utility Model Content

[0006] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present invention proposes a device for optimizing the co-production of acid production from desulfurization wastewater and ammonium thiocyanate.

[0007] The technical solution adopted by the utility model to solve the technical problem is: a device for optimizing the co-production of acid and ammonium thiocyanate from desulfurization waste liquid, comprising a tank body and a cover body, wherein the cover body is matched with the tank body, and the cover body is provided with a stirring motor, and the stirring motor is connected to a stirring paddle arranged in the tank body;

[0008] A jacket is provided on the outer wall of the tank body, a cooling cavity is formed between the jacket and the outer wall of the tank body, a medium inlet and a medium outlet are provided on the jacket, and the medium inlet and the medium outlet are both connected to the cooling cavity;

[0009] A filter plate is provided in the tank body; an ammonium thiocyanate mother liquor outlet and a sulfide impurity discharge port are provided at the lower part of the side wall of the tank body; a differential pressure level gauge and a thermometer are provided in the tank body; and a sulfur-containing concentrate inlet and a backwash liquid inlet are provided on the cover body.

[0010] In a preferred embodiment of the present invention, the cover body is further provided with a VOC collection port, a compressed air inlet and a sight glass.

[0011] In a preferred embodiment of the present invention, a heating coil is provided on the outer wall of the tank.

[0012] In a preferred embodiment of the present invention, a maintenance manhole is further provided on the tank body.

[0013] In a preferred embodiment of the present invention, the filter plate is a metal microporous filter plate.

[0014] The beneficial effects of the utility model are as follows: the device does not have an incineration structure and process, which solves the problem that high-value-added ammonium thiocyanate is incinerated in the existing desulfurization foam and desulfurization waste liquid acid production process, solves the problem of excessive nitrogen oxides in the acid production incineration process, and thus solves the problem of excessive nitric acid in the finished acid; the device has a simple structure and also solves the problem that the existing sulfide impurity removal system has many equipment and is difficult to control; and the gas in the tank is collected through the VOC collection port, solving the problem of strong odor at the salt extraction site; the process of preparing ammonium thiocyanate from sulfur-containing concentrated liquid and obtaining sulfur-containing waste liquid for acid production are combined into one through the device, reducing process energy consumption, saving resources and costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the utility model;

[0016] In the figure: tank body 1; cover body 2; stirring motor 3; stirring paddle 4; jacket 5; medium inlet 6; medium outlet 7; filter plate 8; ammonium thiocyanate mother liquor outlet 9; sulfide impurity discharge port 10; differential pressure level gauge 11; thermometer 12; sulfur-containing concentrate inlet 13; backwash liquid inlet 14; VOC collection port 15; compressed air inlet 16; sight glass 17; heating coil 18; inspection manhole 19. DETAILED DESCRIPTION

[0017] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0019] like Figure 1 The device shown is a device for optimizing the co-production of acid production and ammonium thiocyanate from desulfurization waste liquid, comprising a tank body 1 and a cover body 2, wherein the cover body 2 is matchedly arranged on the tank body 1, and a stirring motor 3 is provided on the cover body 2, and the stirring motor 3 is connected to a stirring paddle 4 arranged in the tank body 1; the stirring motor 3 in the present application is located directly above the cover body 2, and the stirring motor 3 is connected to the stirring shaft through a reducer, and the stirring paddle 4 is arranged on the stirring shaft below, and the stirring shaft is driven to rotate by the stirring motor 3, thereby realizing that the stirring shaft drives the stirring paddle 4 to rotate to stir the liquid in the tank body 1;

[0020] A jacket 5 is provided on the outer wall of the tank body 1, and a cooling cavity is formed between the jacket 5 and the outer wall of the tank body 1. A medium inlet 6 and a medium outlet 7 are provided on the jacket 5. Both the medium inlet 6 and the medium outlet 7 are connected to the cooling cavity. A cooling medium is injected into the cooling cavity through the medium inlet 6, and the cooling medium in the cooling cavity that has undergone heat exchange is discharged through the medium outlet 7. The cooling medium in this application is cooling water;

[0021] A filter plate 8 is provided in the tank body 1. As a preferred embodiment, the filter plate 8 in this application is a metal microporous filter plate to improve the separation efficiency of crystals and liquid; an ammonium thiocyanate mother liquor outlet 9 and a sulfide impurity discharge port 10 are provided at the lower part of the side wall of the tank body 1; a differential pressure level gauge 11 and a thermometer 12 are provided in the tank body 1; and a sulfur-containing concentrate inlet 13 and a backwash liquid inlet 14 are provided on the cover body 2.

[0022] As a preferred embodiment, the cover body 2 in the present application is also provided with a VOC collection port 15, a compressed air inlet 16 and a peephole 17. The VOC collection port is used to collect the VOC gas in the tank body 1 to reduce environmental pollution; compressed air is injected into the tank body 1 through the compressed air inlet 16 to improve the filtration efficiency of the liquid from the filter plate 8; the peephole 17 is used to realize real-time observation of the liquid in the tank body 1 to ensure that each process of the liquid in the tank body 1 is carried out in an orderly manner.

[0023] As a preferred embodiment, a heating coil 18 is provided on the outer wall of the tank body 1 in the present application. And the tank body 1 is also provided with an inspection manhole 19, through which the inspection and maintenance of the tank body 1 can be achieved.

[0024] The device for optimizing the co-production of acid and ammonium thiocyanate from desulfurized wastewater in this application separates ammonium thiocyanate mother liquor and raw materials for acid production from the sulfur-containing concentrated liquid entering the tank body 1 through the sulfur-containing concentrated liquid inlet 13 through cooling crystallization, filtration, and backwashing. The specific process is as follows:

[0025] Cooling crystallization process: the sulfur-containing concentrated liquid enters the tank body 1 through the sulfur-containing concentrated liquid inlet 13, and the sulfur-containing concentrated liquid is stopped from entering when it is determined by the differential pressure liquid level gauge 11 that the sulfur-containing concentrated liquid has entered 3 / 4 of the height in the tank body; the medium inlet 6 is opened, and the cooling liquid is injected into the cooling cavity. The cooling liquid in this application is cooling water, and the cooling water is used to cool the sulfur-containing concentrated liquid in the tank body 1. At the same time, the stirring motor 3 is started, and the stirring paddle 4 is driven by the stirring motor 3 to rotate to achieve stirring of the sulfur-containing concentrated liquid, thereby improving the cooling efficiency of the sulfur-containing concentrated liquid. The temperature of the sulfur-containing concentrated liquid is monitored by a thermometer 12 provided on the side wall of the tank body 1. When the temperature of the sulfur-containing concentrated liquid in the tank body 1 drops to 65°C, the medium inlet is closed and the cooling water in the cooling cavity is discharged through the medium outlet; in the process of the temperature of the sulfur-containing concentrated liquid dropping to 65°C, ammonium thiosulfate gradually precipitates and crystallizes, and the liquid after the sulfur-containing concentrated liquid precipitates ammonium thiocyanate mother liquor;

[0026] Filtration process: open the ammonium thiocyanate mother liquor outlet 9, which is connected to the ammonium thiocyanate crystallization kettle, stop the stirring motor, and open the compressed air inlet valve 16 at the same time. The compressed air entering through the compressed air inlet valve 16 increases the filtration speed of the ammonium thiocyanate mother liquor from the filter plate 8, allowing the ammonium thiocyanate mother liquor solution to pass through the metal microporous filter plate, filtering the ammonium thiosulfate and retaining it on the filter plate 8, thereby achieving separation of the ammonium thiocyanate mother liquor and ammonium thiosulfate to obtain the ammonium thiocyanate mother liquor;

[0027] Backwashing process: When no more ammonium thiocyanate mother liquor flows out, close the compressed air inlet valve 16, open the VOC collection port 15, open the backwash liquid inlet 14, and let the heated centrifuge liquid enter the tank body 1 from the backwash liquid inlet 14. At the same time, open the bottom steam heating coil 18, and when the temperature in the tank body 1 is raised to 85°C, start the stirring motor 3 to achieve the centrifuge liquid to gradually crystallize and fully dissolve the ammonium thiosulfate. The dissolution time is about 10 minutes. The dissolved solution is discharged to the miscellaneous salt tank through the thio impurity vent 10 to obtain sulfur-containing waste liquid, which is convenient for subsequent acid production and becomes the raw material for acid production.

[0028] The centrifuge used in the backwash process is prepared from the ammonium thiocyanate mother liquor that flows out of tank body 1 during the filtration process. Specifically, the ammonium thiocyanate mother liquor flowing out of tank body 1 is cooled and crystallized in an ammonium thiocyanate crystallizer and then centrifuged to extract the ammonium thiocyanate from the ammonium thiocyanate mother liquor. The liquid after the ammonium thiocyanate extraction is used as the centrifuge for backwashing. Using the solution after the ammonium thiocyanate extraction as the centrifuge for backwashing achieves water-free addition to the tank body, achieving material and water balance within tank body 1, reducing the processing cost of adding other liquids as centrifuge, and conserving resources.

[0029] The present application first cools the sulfur-containing concentrated liquid to crystallize the ammonium thiosulfate in the sulfur-containing concentrated liquid, and the liquid from which the ammonium thiosulfate crystals are precipitated is the ammonium thiocyanate mother liquor, thereby separating the ammonium thiocyanate mother liquor from the ammonium thiosulfate. After the ammonium thiocyanate mother liquor is subjected to the cooling, crystallization and centrifugation processes, ammonium thiocyanate is obtained. The ammonium thiosulfate is mixed with the centrifuge liquid and heated at the same time to obtain the raw material for acid production, namely the sulfur-containing waste liquid. The present application optimizes the desulfurization waste liquid acid production and ammonium thiocyanate co-production device. Since the device does not have an incineration structure and process, it solves the problem of high-value-added ammonium thiocyanate being incinerated in the existing desulfurization foam and desulfurization waste liquid acid production process, solves the problem of excessive nitrogen oxides in the acid production incineration process, and thus solves the problem of excessive nitrate in the finished acid. The device has a simple structure and solves the problem of multiple equipment and difficult control in the existing sulfur impurity removal system. The VOC collection port is used to collect gas in the tank, solving the problem of strong odor at the salt extraction site. It solves the system hot and cold disease problem and reduces process energy consumption.

[0030] Throughout this specification, references to terms such as "one embodiment," "certain embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" indicate that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0031] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A device for optimizing the co-production of acid and ammonium thiocyanate from desulfurization wastewater, characterized in that: It comprises a tank body (1) and a cover body (2), wherein the cover body (2) is arranged on the tank body (1) in a matching manner; A jacket (5) is provided on the outer wall of the tank body (1), a cooling cavity is formed between the jacket (5) and the outer wall of the tank body (1), a medium inlet (6) and a medium outlet (7) are provided on the jacket (5), and both the medium inlet (6) and the medium outlet (7) are connected to the cooling cavity; A filter plate (8) is provided in the tank body (1); an ammonium thiocyanate mother liquor outlet (9) and a sulfide impurity discharge port (10) are provided at the lower portion of the side wall of the tank body (1); a differential pressure level gauge (11) and a thermometer (12) are provided in the tank body (1); and a sulfur-containing concentrated liquid inlet (13) and a backwash liquid inlet (14) are provided on the cover body (2).

2. The device for optimizing the co-production of acid and ammonium thiocyanate from desulfurization waste liquid according to claim 1, characterized in that: The cover (2) is also provided with a VOC collection port (15), a compressed air inlet (16) and a viewing mirror (17).

3. The device for optimizing the co-production of acid and ammonium thiocyanate from desulfurization waste liquid according to claim 1, characterized in that: A heating coil (18) is provided on the outer wall of the tank body (1).

4. The device for optimizing the co-production of acid and ammonium thiocyanate from desulfurization waste liquid according to claim 3, characterized in that: The tank body (1) is also provided with a maintenance manhole (19).

5. The device for optimizing the co-production of acid and ammonium thiocyanate from desulfurization waste liquid according to claim 1, characterized in that: The filter plate (8) is a metal microporous filter plate.

6. The device for optimizing the co-production of acid and ammonium thiocyanate from desulfurization wastewater according to any one of claims 1 to 5, characterized in that: A stirring motor (3) is provided on the cover (2), and the stirring motor (3) is connected to a stirring paddle (4) provided in the tank (1).

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