Low-cost industrial strong brine resourceful treatment system

Abstract

The utility model discloses a low-cost industrial strong brine resourceful treatment system, relates to the field of industrial wastewater treatment, and particularly relates to the low-cost industrial strong brine resourceful treatment system. Comprising a homogenizing unit, a precise filtering unit, a special concentration unit, an induced crystallization unit, a reaction crystallization unit, a filtering unit, a deep silicon removal and membrane separation unit, a multi-effect evaporation crystallization unit and an aging mother liquor treatment unit which are connected in sequence, the special concentration unit is one of a flat plate reverse osmosis assembly, a disc tube type reverse osmosis assembly, an electrodialysis assembly and an electro-adsorption desalination assembly. According to the utility model, the addition of chemical agents is greatly reduced, and the agent treatment cost of the system is reduced; the operation pressure and the energy consumption are greatly reduced, and the resource utilization of salts is realized.

Description

Technical Field

[0001] The utility model relates to the field of industrial wastewater treatment, and particularly relates to a low-cost industrial concentrated salt water resource treatment system. Background Art

[0002] For coal chemical industry, chemical industry and coal mines, wastewater is discharged from chemical production (generated during the mining process), which is both a by-product and a new resource. Usually, high-salt (high-suspended solids) coal chemical wastewater and mine water are treated by processes such as coagulation, sedimentation, clarification, filtration and air flotation to remove coarse particles, suspended solids and oil. The concentrated brine after pretreatment is further treated by deep treatment such as reverse osmosis membrane / ion exchange to achieve the purpose of recycling coal chemical wastewater and mine water. Finally, the salts in the concentrated brine are recycled through evaporation crystallization to achieve the separation and recycling of water and salt. The existing process route is relatively long, and a large amount of chemicals are added in the hard removal and concentration units. The chemicals added in these two units account for more than 80% of the total chemical cost of the whole system. Therefore, the investment in zero-discharge (deep treatment) projects is large and the operating cost is high. Especially, the variable cost per ton of water for operation reaches 14 yuan, which increases a relatively high cost pressure on enterprises.

[0003] In view of this, it is necessary to explore a low-cost industrial concentrated salt water resource treatment system, which is more adaptable to the trend of technological development and brings long-term benefits to enterprises. Content of the Utility Model

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the utility model is to provide a low-cost industrial concentrated salt water resource treatment system, which greatly reduces the addition of chemical agents, reduces the chemical treatment cost of the system; greatly reduces the operating pressure and energy consumption, and realizes the resource utilization of salts.

[0005] A low-cost industrial concentrated salt water resource treatment system of the utility model comprises a homogeneous unit, a precision filtration unit, a special concentration unit, an induced crystallization unit, a reaction crystallization unit, a filtration unit, a deep silicon removal unit, a membrane separation unit, a multi-effect evaporation crystallization unit and an aging mother liquor treatment unit which are connected in sequence;

[0006] The special concentration unit is one of a plate reverse osmosis module, a disk tube reverse osmosis module, an electrodialysis module or an electro-adsorption desalination module.

[0007] Preferably, the multi-effect evaporation crystallization unit comprises a sodium chloride evaporation crystallization module and a sodium sulfate evaporation crystallization module;

[0008] The sodium sulfate evaporation crystallization module comprises a freezing crystallizer and a hot melt evaporation crystallizer which are connected;

[0009] The membrane separation unit is provided with a concentrated water side outlet and a product water side outlet. The concentrated water side outlet is connected to a concentrated water tank, and the concentrated water tank is connected to a freeze evaporation crystallizer. A centrifugal dryer is connected to the hot melt evaporation crystallizer.

[0010] The product water side outlet is connected to a product water tank, and the product water tank is connected to a centrifugal dryer through a sodium chloride evaporation crystallization assembly.

[0011] Preferably, it further includes a miscellaneous salt crystallizer. The miscellaneous salt crystallizer is connected to the freeze crystallizer, and a centrifuge is also connected to the miscellaneous salt crystallizer. The miscellaneous salt crystallizer is also connected to the aged mother liquor treatment unit.

[0012] Preferably, the precision filtration unit is a plate membrane module or a submerged ultrafiltration module.

[0013] Preferably, the filtration unit is one or a combination of two of a multi-media filter or an ultrafiltration device.

[0014] Preferably, the deep silicon removal unit includes a pipeline mixer and a precipitation treatment unit arranged along the water flow direction. A chemical dosing pipeline is connected to the pipeline mixer, and the chemical is at least one of magnesium chloride and magnesium sulfate.

[0015] Preferably, the membrane separation unit is a nanofiltration membrane with a pore size of 1-2 nm.

[0016] The utility model adopts a special concentration unit, which can improve the online rate of the system and does not require frequent chemical cleaning.

[0017] By adding crystal seeds and controlling reasonable technical parameters in the utility model, raw water with supersaturated calcium sulfate can continuously generate new crystal seeds in the reactor, achieving cycle after cycle without introducing new dissolved substances into the water. The induced crystallization unit can reduce the salt content of the raw water, and the higher the calcium sulfate in the raw water, the greater the removal amount and the more the salt content in the water is reduced.

[0018] The utility model innovates the traditional "hardness removal by chemical addition - membrane concentration" into "special concentration unit - induced crystallization", greatly reducing the chemical treatment cost of the system; making the TDS reduction effect of all other units significant, and further reducing the operating pressure and energy consumption of all subsequent units;

[0019] The "membrane separation unit + multi-effect evaporation crystallization unit + aged mother liquor treatment unit" of the utility model produces high-purity sodium chloride and sodium sulfate, meeting the quality requirements of industrial-grade products and realizing the resource utilization of salts. Description of the Drawings

[0020] Figure 1 It is a structural block diagram of the utility model. Detailed Embodiments

[0021] The utility model relates to a low-cost industrial concentrated saline water resource treatment system, which comprises a homogenizing unit, a precision filtration unit, a special concentration unit, an induced crystallization unit, a reaction crystallization unit, a filtration unit, a deep silicon removal unit, a membrane separation unit, a multi-effect evaporation crystallization unit, and an aging mother liquor treatment unit, which are connected in sequence;

[0022] The special concentration unit is one of a plate reverse osmosis module, a disk tube reverse osmosis module, an electrodialysis module, or an electro-adsorption desalination module.

[0023] The multi-effect evaporation crystallization unit comprises a sodium chloride evaporation crystallization module and a sodium sulfate evaporation crystallization module;

[0024] The sodium sulfate evaporation crystallization module comprises a freezing crystallizer and a hot melt evaporation crystallizer which are connected;

[0025] A concentrated water side outlet and a product water side outlet are arranged on the membrane separation unit. The concentrated water side outlet is connected with a concentrated water tank, the concentrated water tank is connected with the freezing evaporation crystallizer, and a centrifugal dryer is connected to the hot melt evaporation crystallizer;

[0026] The product water side outlet is connected with a product water tank, and the product water tank is connected with a centrifugal dryer through the sodium chloride evaporation crystallization module.

[0027] It further comprises a miscellaneous salt crystallizer. The sodium chloride evaporation crystallization module is connected with the miscellaneous salt crystallizer, a centrifuge is further connected to the miscellaneous salt crystallizer, and the miscellaneous salt crystallizer is further connected with the aging mother liquor treatment unit.

[0028] The precision filtration unit is a plate membrane module or a submerged ultrafiltration module.

[0029] The filtration unit is one or a combination of two of a multi-media filter or an ultrafiltration device.

[0030] The deep silicon removal unit comprises a pipeline mixer and a precipitation treatment unit arranged along the water flow direction. A chemical agent dosing pipeline is connected to the pipeline mixer, and the chemical agent is at least one of magnesium chloride and magnesium sulfate.

[0031] The membrane separation unit is a nanofiltration membrane with a pore size of 1-2 nm, which is a functional semi-permeable membrane allowing solvent molecules or low-valence ions to pass through, and the ability to intercept dissolved salts is between 2-98%, and it can preferably separate sodium chloride and sodium sulfate in the concentrated saline water initially.

[0032] In the reaction crystallization unit, Ca(OH)2 and Na2CO3 are added step by step. First, a sufficient amount of Ca(OH)2 is added to reduce silicon to a relatively low range. After precipitation, Na2CO3 is added to reduce the total hardness, and at the same time, the effects of efficient silicon and hardness removal are achieved.

[0033] The technological process of the utility model is as follows: The circulating water blowdown, desalinated water concentrate, and the effluent from the sewage treatment plant coming from the front-end system first enter the homogenization unit, which can be set as a homogenization tank or a homogenization concrete pool. The main purpose is to homogenize and equalize the water coming from the front end to ensure the stable quality of the water entering the subsequent unit. Then, through the precision filtration unit, submerged ultrafiltration is used to remove coarse particles and suspended solids.

[0034] Then, it enters the special concentration unit to concentrate the ions, and then enters the induced crystallization unit. By adding crystal seeds to the supersaturated calcium sulfate dissolved in water and controlling reasonable technical parameters, new crystal seeds continuously generate in the reaction crystallization unit from the raw water with supersaturated calcium sulfate, achieving cycle after cycle. The special concentration unit and the induced crystallization unit are used to complete the purposes of desalination and hardness removal. The induced crystallization unit can replace chemical reagent precipitation processes such as mechanical addition tanks and high-density tanks in the existing zero-discharge process. By using the utility model, the investment and variable operating costs can be reduced by 30%. The induced crystallization unit will discharge recoverable calcium sulfate or calcium carbonate, and these solids can all be recycled and reused.

[0035] Then, it passes through the filtration unit, a multi-media filter or an ultrafiltration device, to control the turbidity and a certain hardness of the produced water, and then passes through the deep silicon removal unit. Finally, through the membrane separation unit, a nanofiltration membrane can be selected for salt separation. The concentrated water enters the freezing crystallizer, hot-melt crystallizer, and centrifugal dryer to produce sodium sulfate. The produced water passes through the evaporation crystallization unit, and sodium chloride is produced after the centrifugal drying unit. The waste liquid from the freezing crystallizer and the evaporation crystallization unit enters the miscellaneous salt crystallizer and centrifuge to produce miscellaneous salt.

[0036] The aging mother liquor treatment unit uses a membrane-type vacuum drying device to treat the aging mother liquor in the miscellaneous salt crystallizer. The water is recovered, and the salt is discharged in the form of solid mixed salt, with the water content of the mixed salt not higher than 5%.

Claims

1. A low-cost industrial brine resource treatment system, characterized in that: It includes a homogenizing unit, a precision filtration unit, a special concentration unit, an induced crystallization unit, a reactive crystallization unit, a filtration unit, a deep silicon removal unit, a membrane separation unit, a multi-effect evaporation crystallization unit, and an aged mother liquor treatment unit connected in sequence; The special concentration unit is one of a flat plate reverse osmosis component, a disc tube reverse osmosis component, an electrodialysis component, or an electric adsorption desalination component.

2. A low-cost industrial brine resource treatment system as claimed in claim 1, characterized in that: The multiple-effect evaporation crystallization unit includes a sodium chloride evaporation crystallization component and a sodium sulfate evaporation crystallization component; The sodium sulfate evaporation crystallization component comprises a connected freezing crystallizer and a hot melt evaporation crystallizer; The membrane separation unit is provided with a concentrated water outlet and a produced water outlet, the concentrated water outlet is connected to a concentrated water tank, the concentrated water tank is connected to a freezing evaporation crystallizer, and the hot melt evaporation crystallizer is connected to a centrifugal dryer; The water production side outlet is connected to a water production tank, and the water production tank is connected to a centrifugal dryer via a sodium chloride evaporation crystallization component.

3. A low-cost industrial brine resource treatment system as claimed in claim 2, characterized in that: It also includes a mixed salt crystallizer, which is connected to the freezing crystallizer. A centrifuge is also connected to the mixed salt crystallizer, and the mixed salt crystallizer is also connected to the aged mother liquor processing unit.

4. A low-cost industrial brine resource treatment system as claimed in claim 1, characterized in that: The precision filtration unit is a plate-type membrane component or an immersed ultrafiltration component.

5. A low-cost industrial brine resource treatment system as claimed in claim 1, characterized in that: The filtration unit is a multi-media filter or an ultrafiltration device, or a combination of the two.

6. A low-cost industrial brine resource treatment system as claimed in claim 1, characterized in that: The deep silicon removal unit comprises a pipeline mixer and a precipitation treatment unit arranged along the water flow direction, the pipeline mixer is connected with a reagent dosing pipeline, and the reagent is magnesium chloride or magnesium sulfate.

7. A low-cost industrial brine resource treatment system as claimed in claim 1, characterized in that: The membrane separation unit is a nanofiltration membrane with a pore size of 1-2 nm.

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