Evaporative crystallization production device for zinc sulfate monohydrate

Abstract

The utility model discloses an evaporative crystallization production device of zinc sulfate monohydrate. The evaporative crystallization production device comprises a preheating unit, a double-effect evaporation concentration crystallization unit, a separation unit, a condensate water unit and a vacuum unit which are connected in sequence, wherein the preheating unit is used for recovering system condensate water waste heat, the double-effect evaporation, concentration and crystallization unit is used for concentrating a zinc sulfate solution and growing and enriching crystals, the separation unit is used for separating zinc sulfate monohydrate from the solution, the condensate water unit is used for collecting evaporation condensate water, and the vacuum unit is used for controlling evaporation vacuum degree; the evaporation section adopts a double-effect countercurrent process, so that the crystallization temperature of zinc sulfate monohydrate is ensured, the steam consumption is saved, the device is more energy-saving and environment-friendly, and meanwhile, the device is simple in process flow, easy to implement, high in automation degree and low in operation cost, meets the requirements of sustainable development, and can be widely applied to the actual industrial production process.

Description

Technical Field

[0001] The utility model belongs to the field of chemical production and chemical wastewater treatment, and specifically relates to an evaporation crystallization production device for zinc sulfate monohydrate. Background Art

[0002] Zinc sulfate monohydrate is widely used in feed additives, chemicals, national defense, fertilizers, mineral processing, pharmaceuticals, rubber, electronics, printing and dyeing agents, gelatin clarifiers and protective agents, electroplating, prevention of fruit tree pests and diseases, circulating cooling water treatment, viscose fibers and nylon fibers, etc. At present, most of the production of zinc sulfate heptahydrate is to obtain zinc sulfate solution by acid leaching, reduction and impurity precipitation of zinc oxide or zinc oxide ore, and finally to produce zinc sulfate heptahydrate crystals by cooling and crystallization. The utility model provides an evaporation crystallization production device and control parameters of zinc sulfate monohydrate hydrate with different crystallization temperatures of zinc sulfate solution, which can directly produce zinc sulfate monohydrate from zinc sulfate solution;

[0003] At the same time, with the rapid development of industry, the types and quantity of wastewater have increased rapidly, and the pollution of water bodies has become increasingly widespread and serious, threatening human health and safety. For industrial wastewater containing high levels of zinc and sulfate ions, the device can be used to recover zinc sulfate monohydrate crystals after obtaining a relatively pure zinc sulfate solution through a pretreatment method, thus achieving the purpose of turning waste into treasure and recycling resources. Utility Model Content

[0004] The utility model aims to overcome the defects of the prior art and provides an evaporation crystallization production device for zinc sulfate monohydrate.

[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: an evaporation crystallization production device for zinc sulfate monohydrate, comprising a preheating unit, a second-effect evaporation concentration unit, a first-effect evaporation crystallization unit, a separation unit, a condensation water unit and a vacuum unit connected in sequence, the preheating unit is connected to the second-effect evaporation concentration crystallization unit, the second-effect evaporation concentration unit is connected to the first-effect evaporation crystallization unit, the first-effect evaporation crystallization unit is connected to the separation unit, the condensation water unit is connected to the second-effect evaporation concentration and the first-effect evaporation crystallization unit, and the vacuum unit is connected to the second-effect evaporation concentration crystallization unit.

[0006] Preferably, the preheating unit comprises a raw material tank, a raw material pump, a distilled water preheater and a fresh steam distilled water preheater which are connected in sequence, and the fresh steam distilled water preheater is connected to the second-effect evaporation concentration unit.

[0007] Preferably, the second-effect evaporation and concentration unit comprises a second-effect forced circulation pump, a second-effect forced circulation heat exchanger, a second-effect gas-liquid separator, a second-effect cyclone separator, and a final-effect condenser connected in sequence; a second-effect material transfer pump is connected to the circulation pipe of the second-effect gas-liquid separator; and the second-effect material transfer pump is connected to the first-effect evaporation and crystallization unit.

[0008] Preferably, the single-effect evaporation crystallization unit comprises a single-effect forced circulation pump, a single-effect forced circulation heat exchanger, a single-effect crystallization separator, and a single-effect cyclone separator connected in sequence; the single-effect crystallization separator is connected to a discharge pump; and the discharge pump is connected to the separation unit.

[0009] Preferably, the separation unit comprises a zinc sulfate thickener, a centrifuge, a mother liquor tank, and a mother liquor pump which are connected in sequence, and the discharge port of the mother liquor pump discharges outward.

[0010] Preferably, the condensate unit includes a condensate tank and a condensate pump, the condensate tank is connected to a first-effect forced circulation heat exchanger, a second-effect forced circulation heat exchanger, and a last-effect condenser, the bottom of the condensate tank is connected to the condensate pump, and the condensate pump is connected to a distilled water preheater.

[0011] Preferably, the final effect condenser is also connected to a vacuum unit, and the vacuum unit includes a vacuum pump and a working fluid supply.

[0012] Preferably, the evaporation gas phase temperature of the second-effect evaporation concentration unit is controlled at 65°C-70°C and the pressure is -75KPa to -69KPa, and the evaporation gas phase temperature of the first-effect evaporation crystallization unit is controlled at 85°C-90°C and the pressure is -43KPa to -30KPa, so that the liquid phase temperature of the first-effect evaporation crystallizer is controlled at 95°C-100°C to crystallize the material.

[0013] Preferably, the fresh steam pressure of the first-effect forced circulation heat exchanger is 100 kPa and the temperature is 120°C.

[0014] Compared with the prior art, the utility model has the following beneficial effects: the evaporation crystallization production device of zinc sulfate monohydrate described in the utility model provides a double-effect evaporation crystallization production process of zinc sulfate monohydrate, and about 0.6t-0.65t of steam is needed to evaporate 1 ton of water, with high thermal efficiency and low power consumption, and reduces dependence on boiler equipment, reduces pollutants, and has little pollution to the environment. Compared with single-effect evaporation and kettle evaporation, it is more energy-saving and environmentally friendly.

[0015] The utility model adopts a double-effect countercurrent process flow, in which the zinc sulfate monohydrate crystallization side is one effect, and aims to control the crystallization temperature of zinc sulfate monohydrate to be greater than 80°C to obtain pure zinc sulfate crystals;

[0016] According to the properties of zinc sulfate monohydrate particles such as coarseness and fineness, the utility model selectively selects a flat scraper bottom-discharging centrifuge as centrifugal equipment, thereby ensuring the separation of zinc sulfate monohydrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 The present invention is a schematic structural diagram of a zinc sulfate monohydrate evaporation and crystallization production device provided in a specific embodiment of the present invention.

[0019] The reference numerals in the figure are as follows: 1. raw material tank; 2. distilled water preheater; 3. raw material pump; 4. fresh steam distilled water preheater; 5. condensate pump; 6. condensate tank; 7. second-effect cyclone separator; 8. second-effect forced circulation heat exchanger; 9. second-effect gas-liquid separator; 10. second-effect forced circulation pump; 11. second-effect transfer pump; 12. first-effect forced circulation heat exchanger; 13. first-effect cyclone separator; 14. first-effect forced circulation pump; 15. first-effect crystallization separator; 16. discharge pump; 17. zinc sulfate thickener; 18. mother liquor pump; 19. mother liquor tank; 20. centrifuge; 21. vacuum pump; 22. final-effect condenser. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0022] It should also be understood that the terms used in this utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in this utility model specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0023] It should be further understood that the term “and / or” used in the present specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0024] like Figure 1 The specific embodiment shown is an evaporation crystallization production device for zinc sulfate monohydrate provided in this embodiment, which can be used in the evaporation crystallization process of preparing zinc monosulfate from zinc sulfate solution.

[0025] See also Figure 1 The evaporation and crystallization production device of zinc sulfate monohydrate comprises a preheating unit, a second-effect evaporation and concentration unit, a first-effect evaporation and crystallization unit, a separation unit, a condensation water unit and a vacuum unit connected in sequence; the preheating unit comprises a raw material tank 1, a raw material pump 3, a distilled water preheater 2 and a fresh steam distilled water preheater 4 connected in sequence; the second-effect evaporation and concentration unit comprises a second-effect forced circulation pump 10, a second-effect forced circulation heat exchanger 8, a second-effect gas-liquid separator 9, a second-effect cyclone separator 7, and a final-effect condenser 22 connected in sequence; the circulation pipe on the second-effect gas-liquid separator 9 is connected with a second-effect material transfer pump 11; the first-effect evaporation and crystallization unit comprises a first-effect forced circulation pump 14, a first-effect forced circulation heat exchanger 12, a first-effect crystallization separator 23 connected in sequence 15, a first-effect cyclone separator 13; the salt leg of the first-effect crystallization separator 15 is provided with a discharge pump 16; the separation unit comprises a zinc sulfate thickener 17, a centrifuge 20, a mother liquor tank 19, and a mother liquor pump 18 connected in sequence; the condensed water unit comprises a condensed water tank 6 and a condensed water pump 5, the condensed water tank 6 is connected to the first-effect forced circulation heat exchanger 12 of the first-effect evaporation crystallization unit, the second-effect forced circulation heat exchanger 8 in the second-effect evaporation concentration unit, and the shell side of the final condenser 22, and the bottom of the condensed water tank 6 is connected to the condensed water pump 5; the final condenser 22 of the second-effect evaporation concentration unit is also connected to a vacuum unit, the vacuum unit comprises a vacuum pump 21 and a working fluid supply, and the vacuum degree of the system is controlled by the vacuum unit.

[0026] In this embodiment, the inlet water temperature of the zinc sulfate solution of the zinc sulfate monohydrate evaporation crystallization production device is 25° C., the mass fraction of zinc sulfate is 24%, and the mass flow rate is 1.3 t / h.

[0027] Among them, Figure 1 As shown, the zinc sulfate solution to be treated is stored in a raw material tank 1, and enters a distilled water preheater 2 and a fresh steam distilled water preheater 4 in sequence through the action of a raw material pump 3, and exchanges heat with the condensed water in the distilled water preheater 2 and the fresh steam condensed water in the fresh steam distilled water preheater 4, so that the raw material liquid temperature reaches 90°C. The distilled water preheater 2 and the fresh steam distilled water preheater 4 are both plate preheaters, and the distilled water preheater 2 is connected to a condensed water tank 6 through a condensed water pump 5.

[0028] The zinc sulfate solution at 90°C enters the inlet of the second-effect forced circulation pump 10, and then enters the second-effect forced circulation heat exchanger 8. After the temperature and pressure are increased, it enters the second-effect gas-liquid separator 9 for flash separation. The evaporation temperature in the second-effect gas-liquid separator 9 is 70°C and the pressure is -69KPa. After flash separation, the concentrated liquid is pumped into the second-effect forced circulation heat exchanger 8 through the second-effect forced circulation pump 10 for heating and evaporation again. The concentrated liquid circulates in this way. The concentrated liquid is sent to the inlet of the first-effect forced circulation pump 14 from the bottom second-effect transfer pump 11, and then enters the first-effect forced circulation heat exchanger 12. After the temperature and pressure are increased, it enters the first-effect crystallization separator 15 for flash separation, and is passed through the vacuum pump 2 1 The evaporation temperature in the first-effect crystal separator 15 is controlled to be 90°C and the pressure is -30KPa; at this time, the liquid phase temperature of the first-effect crystallizer is 95°C-100°C; after flash separation, the concentrated liquid is pumped into the first-effect forced circulation heat exchanger 12 through the first-effect forced circulation pump 14 for heating and evaporation again, and the concentrated liquid is circulated in this way, and the concentrated liquid is sent to the zinc sulfate monohydrate thickener 17 from the bottom discharge pump 16, and the crystals are discharged into the zinc sulfate monohydrate centrifuge 20 for centrifugal separation after thickening, and the zinc sulfate monohydrate crystals are separated and sent out of the system, and the separated mother liquor enters the zinc sulfate mother liquor tank 19, and is pumped back to the first-effect forced circulation heat exchanger 12 through the mother liquor pump 18, and the cycle is repeated. The zinc sulfate monohydrate crystals obtained by centrifugal separation are sent out of the system.

[0029] The evaporation crystallization production device of zinc sulfate monohydrate described in this embodiment has a zinc sulfate feed temperature of 25°C, a feed amount of 1.3 t / h, a zinc sulfate mass fraction of 24%, and a mass flow rate of 1.3 t / h; a sodium chloride zinc sulfate solution with a mass fraction of 24%, a zinc sulfate mass fraction flow rate of 10%, and 5 t / h. The operating parameters are shown in Table 1.

[0030] Table 1 Operating parameters

[0031]

[0032] The evaporation and crystallization production device of zinc sulfate monohydrate described in the utility model provides a double-effect evaporation and crystallization production process of zinc sulfate monohydrate. It takes about 0.6t-0.65t of steam to evaporate 1 ton of water. It has high thermal efficiency and low power consumption, reduces dependence on boiler equipment, reduces pollutants, and has little pollution to the environment. Compared with single-effect evaporation and kettle evaporation, it is more energy-saving and environmentally friendly.

[0033] The above-mentioned novel method adopts a double-effect countercurrent process, in which the zinc sulfate monohydrate crystallization side is one effect, aiming to control the crystallization temperature of zinc sulfate monohydrate to be greater than 80°C to obtain pure zinc sulfate crystals.

[0034] According to the properties of zinc sulfate monohydrate such as fine particle size, the utility model specifically selects a flat scraper bottom discharge centrifuge as the centrifugal equipment, which can ensure the separation of zinc sulfate monohydrate.

[0035] The above examples are only used to further illustrate the technical content of the utility model, so that readers can understand it more easily, but it does not mean that the implementation methods of the utility model are limited to this. Any technical extension or re-creation made based on the utility model is protected by the utility model. The protection scope of the utility model shall be based on the claims.

Claims

1. An evaporation crystallization production device for zinc sulfate monohydrate, characterized in that: The invention comprises a preheating unit, a second-effect evaporation concentration unit, a first-effect evaporation crystallization unit, a separation unit, a condensation water unit and a vacuum unit which are connected in sequence. The preheating unit is connected to the second-effect evaporation concentration crystallization unit, the second-effect evaporation concentration unit is connected to the first-effect evaporation crystallization unit, the first-effect evaporation crystallization unit is connected to the separation unit, the condensation water unit is connected to the second-effect evaporation concentration unit and the first-effect evaporation crystallization unit, and the vacuum unit is connected to the second-effect evaporation concentration crystallization unit.

2. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 1, characterized in that: The preheating unit comprises a raw material tank (1), a raw material pump (3), a distilled water preheater (2) and a fresh steam distilled water preheater (4) which are connected in sequence, and the fresh steam distilled water preheater (4) is connected to the second-effect evaporation concentration unit.

3. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 2, characterized in that: The second-effect evaporation and concentration unit comprises a second-effect forced circulation pump (10), a second-effect forced circulation heat exchanger (8), a second-effect gas-liquid separator (9), a second-effect cyclone separator (7), and a final-effect condenser (22) which are connected in sequence; a second-effect material transfer pump (11) is connected to the circulation pipe of the second-effect gas-liquid separator (9); and the second-effect material transfer pump (11) is connected to the first-effect evaporation and crystallization unit.

4. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 3, characterized in that: The single-effect evaporation crystallization unit comprises a single-effect forced circulation pump (14), a single-effect forced circulation heat exchanger (12), a single-effect crystallization separator (15), and a single-effect cyclone separator (13) which are connected in sequence; the single-effect crystallization separator (15) is connected to a discharge pump (16); and the discharge pump (16) is connected to the separation unit.

5. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 4, characterized in that: The separation unit comprises a zinc sulfate thickener (17), a centrifuge (20), a mother liquor tank (19), and a mother liquor pump (18) which are connected in sequence, and the discharge port of the mother liquor pump (18) discharges outward.

6. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 3 or 4, characterized in that: The condensate unit comprises a condensate tank (6) and a condensate pump (5); the condensate tank (6) is connected to a first-effect forced circulation heat exchanger (12), a second-effect forced circulation heat exchanger (8), and a final-effect condenser (22); the bottom of the condensate tank (6) is connected to the condensate pump (5), and the condensate pump (5) is connected to a distilled water preheater (2).

7. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 3, characterized in that: The final effect condenser (22) is also connected to a vacuum unit, which includes a vacuum pump (21) and a working fluid supply.

8. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 3 or 4, characterized in that: The evaporation gas phase temperature of the second-effect evaporation concentration unit is controlled at 65°C-70°C and the pressure is -75KPa~-69KPa, and the evaporation gas phase temperature of the first-effect evaporation crystallization unit is controlled at 85°C-90°C and the pressure is -43KPa~-30KPa, so that the liquid phase temperature of the first-effect evaporation crystallizer is controlled at 95°C-100°C to crystallize the material.

9. The evaporation crystallization production device of zinc sulfate monohydrate according to claim 8, characterized in that: The fresh steam pressure of the first-effect forced circulation heat exchanger (12) is 100 kPa and the temperature is 120°C.

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