Sodium bromide recovery system

Abstract

The utility model discloses a sodium bromide recovery system, and particularly relates to the technical field of waste water resource recovery, the sodium bromide recovery system comprises a microfiltration impurity removal unit, a filtration separation unit and an evaporative crystallization unit, the microfiltration impurity removal unit comprises a reaction sedimentation tank and a tubular microfiltration device, the reaction sedimentation tank is connected and communicated with the tubular microfiltration device, and the tubular microfiltration device is communicated with the filtration separation unit. The tubular microfiltration device is used for filtering a filtered mud mixed solution from the reaction sedimentation tank, a filtrate outlet of the tubular microfiltration device is connected and communicated with an inlet of the nanofiltration membrane filtration device of the filtration separation unit, and the nanofiltration membrane filtration device is used for separating sodium bromide in the filtrate; the evaporative crystallization unit comprises a carnallite evaporative crystallization device and a sodium bromide evaporative crystallization device, a membrane thin liquid outlet of the nanofiltration membrane filtering device is connected with the sodium bromide evaporative crystallization device, and a membrane concentrated liquid outlet of the nanofiltration membrane filtering device is connected with the carnallite evaporative crystallization device. According to the device, the impurity removal effect can be improved, the recovery rate and the purity of sodium bromide are improved, and resource recovery of wastewater is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater resource recovery, in particular to a sodium bromide recovery system. Background Art

[0002] Bromine is one of the important chemical raw materials. As a precious and non-renewable rare element, its derived inorganic bromides, bromates and bromine-containing organic compounds have made important contributions to the national economy and scientific and technological development. The main components of bromine-containing wastewater generated in the petrochemical, pharmaceutical, pesticide, waste circuit board and other industries are sodium bromide and sodium sulfate. It also contains impurities such as heavy metals, calcium, magnesium, fluorine, etc. It has the characteristics of high salt, high COD and high ammonia nitrogen. The composition is complex, and various substances have the characteristics of blending, azeotropy and commonality. At present, the mainstream treatment method for bromine-containing wastewater is evaporation and crystallization after pretreatment. The impurity removal effect is poor, but the composition after evaporation and crystallization is complex, and the recovery rate of sodium bromide is low. From the perspective of resource recovery, it is a waste of sodium bromide. Utility Model Content

[0003] The utility model aims to provide a sodium bromide recovery system to solve the problems existing in the above-mentioned prior art, improve the impurity removal effect, improve the recovery rate and purity of sodium bromide, and realize the resource recovery of wastewater.

[0004] To achieve the above purpose, the utility model provides the following solutions:

[0005] The utility model provides a sodium bromide recovery system, comprising a microfiltration impurity removal unit, a filtration separation unit and an evaporation crystallization unit, wherein the microfiltration impurity removal unit comprises a reaction sedimentation tank and a tubular microfiltration device, wherein the reaction sedimentation tank is connected and communicated with an inlet of the tubular microfiltration device, wherein the tubular microfiltration device is used for filtering a sludge mixed liquid from the reaction sedimentation tank, wherein the filtration separation unit comprises a nanofiltration membrane filtration device, wherein a filtrate outlet of the tubular microfiltration device is connected and communicated with an inlet of the nanofiltration membrane filtration device, wherein the nanofiltration membrane filtration device is used for separating sodium bromide from filtrate, wherein the evaporation crystallization unit comprises a miscellaneous salt evaporation crystallization device and a sodium bromide evaporation crystallization device, wherein a membrane thin liquid outlet of the nanofiltration membrane filtration device is connected with the sodium bromide evaporation crystallization device, and a membrane concentrated liquid outlet of the nanofiltration membrane filtration device is connected with the miscellaneous salt evaporation crystallization device.

[0006] Preferably, the filtration and separation unit also includes a membrane concentrating device, the membrane dilute liquid outlet of the nanofiltration membrane filtration device is connected and communicated with the inlet of the membrane concentrating device, the membrane concentrating device is used to concentrate the concentration of the sodium bromide solution, and the outlet of the membrane concentrating device is connected to the sodium bromide evaporation and crystallization device.

[0007] Preferably, the nanofiltration membrane filtration device includes a primary nanofiltration membrane filtration device and a secondary nanofiltration membrane filtration device, the filtrate outlet of the tubular microfiltration device is connected and communicated with the inlet of the primary nanofiltration membrane filtration device, the membrane dilute liquid outlet of the primary nanofiltration membrane filtration device is connected and communicated with the inlet of a membrane concentration device, the membrane concentrate liquid outlet of the primary nanofiltration membrane filtration device is connected and communicated with the inlet of the secondary nanofiltration membrane filtration device, the membrane dilute liquid outlet of the secondary nanofiltration membrane filtration device is connected and communicated with the inlet of the membrane concentration device, and the membrane concentrate liquid outlet of the secondary nanofiltration membrane filtration device is connected to the mixed salt evaporation and crystallization device.

[0008] Preferably, the filter mud outlet of the tubular microfiltration device is connected to the filter mud concentration zone of the reaction sedimentation tank, and the filter mud after filtering the filter mud mixed liquid by the tubular microfiltration device can be transported to the filter mud concentration zone of the reaction sedimentation tank.

[0009] Preferably, the microfiltration impurity removal unit further comprises a plate and frame filter press device, which is connected and communicated with the filter mud concentration zone of the reaction sedimentation tank, and the plate and frame filter press device is used for filtering the filter mud into filter residue.

[0010] Preferably, the turbidity of the filtrate of the tubular microfiltration device is less than 0.2 NTU.

[0011] Compared with the prior art, the utility model has achieved the following technical effects:

[0012] The utility model provides a sodium bromide recovery system. Bromine-containing wastewater enters a reaction sedimentation tank, which can cause impurity ions in the bromine-containing wastewater to form precipitation, and a sludge mixed liquid in the reaction sedimentation tank is transported to a tubular microfiltration device to separate the filtrate from the sludge, thereby removing sludge impurities such as calcium, magnesium, heavy metals, fluorine, etc. in the bromine-containing wastewater. The reaction sedimentation tank and the tubular microfiltration device have good impurity removal effects. The filtrate flowing out of the tubular microfiltration device enters a nanofiltration membrane filtration device, and a sodium bromide solution and a miscellaneous salt solution in the filtrate are separated by the nanofiltration membrane filtration device. The sodium bromide solution is transported to a sodium bromide evaporation crystallization device for evaporation and crystallization to obtain a sodium bromide product, thereby improving the recovery rate and purity of the sodium bromide. The miscellaneous salt solution enters the miscellaneous salt evaporation crystallization device for evaporation and crystallization to obtain miscellaneous salt with sodium sulfate as a main component, thereby realizing resource recovery of bromine-containing wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only 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.

[0014] Figure 1 It is a structural schematic diagram of the sodium bromide recovery system of the utility model.

[0015] In the figure: 1-reaction sedimentation tank; 2-tubular microfiltration device; 3-plate and frame filter press device; 4-primary nanofiltration membrane filtration device; 5-secondary nanofiltration membrane filtration device; 6-membrane concentration device; 7-sodium bromide evaporation crystallization device; 8-miscellaneous salt evaporation crystallization device. DETAILED DESCRIPTION

[0016] 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 only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in 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.

[0017] The utility model aims to provide a sodium bromide recovery system to solve the problems existing in the above-mentioned prior art, improve the impurity removal effect, improve the recovery rate and purity of sodium bromide, and realize the resource recovery of wastewater.

[0018] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0019] The utility model provides a sodium bromide recovery system, such as Figure 1 As shown, it includes a microfiltration impurity removal unit, a filtration separation unit and an evaporation crystallization unit. The microfiltration impurity removal unit includes a reaction sedimentation tank 1 and a tubular microfiltration device 2. The reaction sedimentation tank 1 is connected and communicated with the inlet of the tubular microfiltration device 2. The tubular microfiltration device 2 is used to filter the sludge mixed liquid from the reaction sedimentation tank 1. The filtration separation unit includes a nanofiltration membrane filtration device. The filtrate outlet of the tubular microfiltration device 2 is connected and communicated with the inlet of the nanofiltration membrane filtration device. The nanofiltration membrane filtration device is used to separate sodium bromide from the filtrate. The evaporation crystallization unit includes a salt evaporation crystallization device 8 and a sodium bromide evaporation crystallization device 7. The membrane dilute liquid outlet of the nanofiltration membrane filtration device is connected to the sodium bromide evaporation crystallization device 7, and the membrane concentrated liquid outlet of the nanofiltration membrane filtration device is connected to the salt evaporation crystallization device 8. The bromine-containing wastewater enters the reaction sedimentation tank 1, and lime milk, sodium hydroxide, sodium carbonate and disodium hydrogen phosphate are added to the reaction sedimentation tank 1 to produce CaCO 3 Mg(OH) 2 and Ca 5 (PO 4 ) 3F and other insoluble precipitates are used to form precipitation of impurity ions in the bromine-containing wastewater, and the filtrate mixture in the reaction sedimentation tank 1 is transported to the tubular microfiltration device 2 to separate the filtrate and the filtrate precipitate, so as to remove the filtrate impurities such as calcium, magnesium, heavy metals, fluorine and the like in the bromine-containing wastewater. The reaction sedimentation tank 1 and the tubular microfiltration device 2 have good impurity removal effects; the filtrate flowing out of the tubular microfiltration device 2 enters the nanofiltration membrane filtration device, which can separate the sodium bromide solution from the impure salt solution in the filtrate, and the sodium bromide solution enters the sodium bromide evaporation and crystallization device 7 from the membrane dilute liquid outlet for evaporation and crystallization to obtain a sodium bromide product, thereby improving the recovery rate and purity of sodium bromide, and the impure salt solution enters the impure salt evaporation and crystallization device 8 from the membrane concentrated liquid outlet for evaporation and crystallization to obtain impure salt with sodium sulfate as the main component, thereby realizing the resource recovery of bromine-containing wastewater.

[0020] In the embodiment of the utility model, it is further preferred that the filtration separation unit also includes a membrane concentrating device 6, the membrane dilute liquid outlet of the nanofiltration membrane filtration device is connected and communicated with the inlet of the membrane concentrating device 6, the membrane concentrating device 6 is used to concentrate the concentration of the sodium bromide solution, and the outlet of the membrane concentrating device 6 is connected to the sodium bromide evaporation crystallization device 7. The membrane concentrating device 6 can use an ultra-high pressure membrane concentrating device, which can concentrate the concentration of the sodium bromide solution to 8-12% (the concentration ratio of the ultra-high pressure membrane concentrating device is 1.5-2.5), which can reduce the amount of evaporated water of the sodium bromide evaporation crystallization device 7 and reduce the investment and production cost of evaporation crystallization.

[0021] In the embodiment of the utility model, it is further preferred that the nanofiltration membrane filtration device includes a primary nanofiltration membrane filtration device 4 and a secondary nanofiltration membrane filtration device 5, the filtrate outlet of the tubular microfiltration device 2 is connected and communicated with the inlet of the primary nanofiltration membrane filtration device 4, the membrane dilute liquid outlet of the primary nanofiltration membrane filtration device 4 is connected and communicated with the inlet of the membrane concentrating device 6, the membrane concentrate liquid outlet of the primary nanofiltration membrane filtration device 4 is connected and communicated with the inlet of the secondary nanofiltration membrane filtration device 5, the membrane dilute liquid outlet of the secondary nanofiltration membrane filtration device 5 is connected and communicated with the inlet of the membrane concentrating device 6, and the membrane concentrate liquid outlet of the secondary nanofiltration membrane filtration device 5 is connected and communicated with the mixed salt evaporation crystallization device 8. The use of a two-stage nanofiltration device can better separate the sodium bromide solution and the mixed salt solution, can separate more than 90% of the sodium bromide solution in the filtrate, and improve the recovery rate of sodium bromide.

[0022] It is further preferred in the embodiment of the utility model that the filter mud outlet of the tubular microfiltration device 2 is connected to the filter mud concentration zone of the reaction sedimentation tank 1, and the filter mud after the tubular microfiltration device 2 filters the filter mud mixed liquid can be transported to the filter mud concentration zone of the reaction sedimentation tank 1. The tubular microfiltration device 2 can concentrate the precipitated filter mud concentration to 30000-50000ppm, and at the same time obtain a filtrate with a turbidity of less than 0.2NTU. The concentrated precipitated filter mud is circulated back to the filter mud concentration zone of the reaction sedimentation tank 1, which is convenient for the subsequent centralized treatment of the filter mud precipitation.

[0023] It is further preferred in the embodiment of the utility model that the microfiltration impurity removal unit also includes a plate and frame filter press device 3, which is connected and communicated with the mud concentration area of ​​the reaction sedimentation tank 1. The plate and frame filter press device 3 is used to filter the concentrated mud into filter residue. The precipitated mud concentrated by the tubular microfiltration device 2 can reduce the processing capacity of the plate and frame filter press device 3 and improve the work efficiency.

[0024] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A sodium bromide recovery system, characterized in that: It includes a microfiltration impurity removal unit, a filtration separation unit and an evaporation crystallization unit. The microfiltration impurity removal unit includes a reaction sedimentation tank and a tubular microfiltration device. The reaction sedimentation tank is connected and communicated with the inlet of the tubular microfiltration device. The tubular microfiltration device is used to filter the sludge mixed liquid from the reaction sedimentation tank. The filtration separation unit includes a nanofiltration membrane filtration device. The filtrate outlet of the tubular microfiltration device is connected and communicated with the inlet of the nanofiltration membrane filtration device. The nanofiltration membrane filtration device is used to separate sodium bromide from the filtrate. The evaporation crystallization unit includes a mixed salt evaporation crystallization device and a sodium bromide evaporation crystallization device. The membrane dilute liquid outlet of the nanofiltration membrane filtration device is connected to the sodium bromide evaporation crystallization device, and the membrane concentrated liquid outlet of the nanofiltration membrane filtration device is connected to the mixed salt evaporation crystallization device.

2. The sodium bromide recovery system according to claim 1, wherein: The filtration separation unit also includes a membrane concentrating device, the membrane dilute liquid outlet of the nanofiltration membrane filtration device is connected and communicated with the inlet of the membrane concentrating device, the membrane concentrating device is used to concentrate the concentration of the sodium bromide solution, and the outlet of the membrane concentrating device is connected to the sodium bromide evaporation crystallization device.

3. The sodium bromide recovery system according to claim 2, wherein: The nanofiltration membrane filtration device includes a primary nanofiltration membrane filtration device and a secondary nanofiltration membrane filtration device. The filtrate outlet of the tubular microfiltration device is connected and communicated with the inlet of the primary nanofiltration membrane filtration device, the membrane dilute liquid outlet of the primary nanofiltration membrane filtration device is connected and communicated with the inlet of a membrane concentration device, the membrane concentrate liquid outlet of the primary nanofiltration membrane filtration device is connected and communicated with the inlet of the secondary nanofiltration membrane filtration device, the membrane dilute liquid outlet of the secondary nanofiltration membrane filtration device is connected and communicated with the inlet of the membrane concentration device, and the membrane concentrate liquid outlet of the secondary nanofiltration membrane filtration device is connected to the mixed salt evaporation and crystallization device.

4. The sodium bromide recovery system according to claim 1, wherein: The filter mud outlet of the tubular microfiltration device is communicated with the filter mud concentration zone of the reaction sedimentation tank, and the filter mud after the filter mud mixed liquid is filtered by the tubular microfiltration device can be transported to the filter mud concentration zone of the reaction sedimentation tank.

5. The sodium bromide recovery system according to claim 4, wherein: The microfiltration impurity removal unit also includes a plate-frame filter press device, which is connected and communicated with the filter mud concentration area of ​​the reaction sedimentation tank, and the plate-frame filter press device is used to filter the filter mud into filter residue.

6. The sodium bromide recovery system according to claim 1, wherein: The turbidity of the filtrate of the tubular microfiltration device is less than 0.2 NTU.

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