Water balance device for smelting plant

Abstract

The utility model provides a smelting plant water balance device which comprises a power generation unit, a demineralized water production unit, a salt-containing wastewater treatment unit and a smelting furnace. According to the technical scheme provided by the utility model, the whole water balance of a smelting plant is optimized by utilizing the LTE low-temperature hot-method evaporation device.

Description

Technical Field

[0001] The utility model relates to the technical field of water treatment in smelters, in particular to a water balance device in smelters. Background Art

[0002] As a pillar industry for the development of the national economy, the non-ferrous smelting industry has been growing and developing continuously. However, the consumption of new process water and the treatment of production wastewater in the smelting process have always been a problem that has plagued the development of enterprises. Recently, relevant documents have made strict regulations on the amount of fresh water used per unit product, the amount of wastewater discharged per unit product, and the reuse rate of industrial water in the non-ferrous smelting industry. Taking copper smelting as an example, it is required that the water recycling rate of copper smelting enterprises using copper concentrate should reach more than 98%, and the consumption of new water per ton of copper should be less than 16 tons.

[0003] The quality of water has an important impact on industrial water consumption. High-quality water use is a key factor in improving the efficiency of circulating water use and helps to significantly reduce the amount of new water used. Taking circulating water as an example, as a major item of industrial water use, circulating water consumption accounts for 50-90% of the total water consumption of enterprises. Due to the restriction of the concentration multiple, circulating cooling water must discharge a certain amount of concentrated water and add a certain amount of new water during operation. The salt content of new water is a key factor restricting the concentration multiple. Improving the water quality of replenishment will help to increase the concentration multiple of circulating water, protect heat exchange equipment, reduce sewage discharge, and reduce the amount of replenishment water.

[0004] The high-quality water commonly required by the nonferrous industry mainly includes: softened water, desalted water, domestic water, etc. In general industrial production processes, various types of raw water are used to prepare high-quality water products. The commonly used treatment process is currently the membrane treatment process. Taking the preparation and use of desalted water as an example, the conventional water treatment process of the desalted water station of a nonferrous smelter mainly adopts the treatment method of filtration + reverse osmosis + mixed ion exchange, and then deoxygenates it through a deaerator and then replenishes it to the waste heat boiler system for use. The main disadvantages of membrane preparation of desalted water are: (1) The equipment has a large footprint, high requirements for influent water, complex pretreatment, long process, and multiple reagents need to be added during operation. Daily cleaning with acid and alkali reagents is frequent, the operating cost is high, and the membrane components generally need to be replaced after 3 to 5 years of operation; (2) The water production rate of the membrane system is less than 70%, the conductivity of the desalted water is high, the quality is poor, and the amount of concentrated water is high, resulting in an increase in the downstream wastewater treatment load and serious waste of water resources.

[0005] Industrial water consumption and drainage are positively correlated. While water consumption increases significantly, the industrial wastewater discharge is bound to rise synchronously. During the production process, high-concentration wastewater is generated in multiple links, such as the desulfurization wastewater in the wet desulfurization link, the concentrated water of the reverse osmosis system in the boiler system, and the sewage discharged from the circulating water after increasing the circulation ratio. And the high-concentration wastewater contains a large amount of pollutants such as salts and heavy metal elements, which must be properly disposed of. How to obtain high-quality new water through the use of low-cost treatment processes can also be regarded as one of the ways to solve the water resource problem. With the implementation of environmental protection policies, the production wastewater generated during the enterprise production process, from the perspective of sustainable development in the industrial economic production process, after appropriate treatment, the wastewater can not only be used as a resource, but also save fresh water sources and reduce sewage discharge. The existing "concentration reduction" process for saline wastewater mainly includes membrane method reduction. The membrane method reduction technology has high requirements for pretreatment, especially for suspended solids, turbidity, and scaling ions. It requires multi-stage softening pretreatment and has a long process; and there are problems such as membrane fouling and blockage, and the system is complex, with high operation difficulty, poor operation stability, high investment and operation costs, and the membrane components of the wastewater treatment system need to be replaced every 1 - 5 years.

[0006] At the same time, it should be noted that there is a relatively large amount of steam in the non-ferrous smelting industry, and the overall plant steam utilization rate is relatively low. For example, the exhausted steam (about 60 - 70 °C) after steam power generation still has a relatively large latent heat of vaporization. Usually, industrial circulating cooling water is required for condensation. After the steam-water heat exchange, the heat enters the circulating cooling return water and is then released into the air through the cooling tower, and the latent heat is not effectively utilized.

[0007] Taking the national copper smelting industry as an example, in 2019, the annual output of refined copper (electrolytic copper) was 9.784 million tons. Calculated based on the new water consumption per ton of copper being 16 tons, the annual new water consumption was 157 million tons, and the wastewater generated was approximately 26.91 million tons. Based on the actual operation situation of the smelter, it is very important to organically combine the efficient utilization of the smelter steam to prepare high-quality produced water and significantly reduce the operation cost of water treatment to optimize the overall plant water balance system.

[0008] In view of this, the present application is specifically proposed. Utility Model Content

[0009] The main purpose of the present utility model is to provide a water balance device for a smelter to solve the problems of excessive water consumption and low steam utilization rate in the existing smelter technology.

[0010] To achieve the above object, according to one aspect of the present utility model, a horizontal balance device for a smelter is provided, including a power generation unit, a demineralized water production unit, a saline wastewater treatment unit, and a smelting furnace; wherein, the power generation unit includes a generator which has an exhaust steam outlet; the demineralized water production unit includes: a first LTE low-temperature thermal evaporation device which has a first exhaust steam inlet, a first exhaust steam condensation port, a softened water inlet, and a first secondary steam outlet, the first exhaust steam inlet is connected to the exhaust steam outlet, and the first LTE low-temperature thermal evaporation device is used to perform low-temperature thermal evaporation on the softened water entering from the softened water inlet with the exhaust steam entering from the first exhaust steam inlet to form a first secondary steam; a first condenser which has a first secondary steam inlet and a first condensate outlet, and the first secondary steam inlet is connected to the first secondary steam outlet; a mixed ion exchanger whose inlet is connected to the first condensate outlet; the saline wastewater treatment unit includes: a slurrying unit which has a saline wastewater inlet, a seed inlet, and a saline wastewater slurry outlet; a second LTE low-temperature thermal evaporation device which has a second exhaust steam inlet, a second exhaust steam condensation port, a saline wastewater slurry inlet, a second secondary steam outlet, and a concentrated water outlet, the second exhaust steam inlet is connected to the exhaust steam outlet, the saline wastewater slurry inlet is connected to the saline wastewater slurry outlet, and the second LTE low-temperature thermal evaporation device is used to perform low-temperature thermal evaporation on the saline wastewater slurry entering from the saline wastewater slurry inlet with the exhaust steam entering from the second exhaust steam inlet to form a second secondary steam and concentrated water; a second condenser which has a second secondary steam inlet and a second condensate outlet, and the second secondary steam outlet is connected to the second secondary steam inlet; the smelting furnace is configured with a post-furnace circulating water unit, and the first condensate outlet and the second condensate outlet are both connected to the furnace body circulating water unit.

[0011] Further, the saline wastewater treatment unit further includes: a solid-liquid separation unit which has a concentrated water inlet, an overflow outlet, and an underflow outlet, the concentrated water inlet is connected to the concentrated water outlet, and the underflow outlet is connected to the seed inlet of the slurrying unit; an evaporation crystallization device which has an overflow inlet, an evaporation crystallization mother liquor outlet, and a crystal salt outlet, and the evaporation crystallization mother liquor outlet is connected to the saline wastewater slurry inlet of the second LTE low-temperature thermal evaporation device.

[0012] Further, the solid-liquid separation unit is a thickener.

[0013] Further, the above device further includes: a deaerator whose inlet is connected to the first exhaust steam condensation port, the outlet of the mixed ion exchanger, and the second condensate outlet.

[0014] Further, the power generation unit further includes a high-pressure steam supply unit for power generation, whose inlet is connected to the outlet of the deaerator and the outlet is connected to the generator.

[0015] Further, the high-pressure steam supply unit includes: a steam drum having a water inlet and a high-pressure steam outlet for power generation, the water inlet being connected to the outlet of the deaerator, and the high-pressure steam outlet for power generation being connected to the generator; a heating unit for heating the deaerated water in the steam drum to obtain high-pressure steam for power generation.

[0016] Further, the heating unit is a boiler.

[0017] Further, the power generation unit further includes a power station circulating water unit for supplying circulating water as a refrigerant to the first condenser and the second condenser.

[0018] Further, the first LTE low-temperature thermal evaporation device and the second LTE low-temperature thermal evaporation device are independently selected from 1 to 20 effects in series.

[0019] Further, the first LTE low-temperature thermal evaporation device and the second LTE low-temperature thermal evaporation device are respectively independently configured with a post-vacuum pump.

[0020] Applying the technical solution of the present utility model, the overall water balance of the smelter is optimized by using the LTE low-temperature thermal evaporation device. Specifically: the present utility model realizes the reduction of production capacity and improvement of quality in the demineralized water production unit and the near-zero discharge in the salt-containing wastewater treatment unit through the application of the LTE low-temperature thermal evaporation device, thereby optimizing the overall water balance of the smelter. This device utilizes the exhaust steam of the generator, evaporates and condenses through the LTE low-temperature thermal evaporation device to obtain distilled water several times the amount of the heating steam, and significantly reduces and approaches zero discharge of the wastewater. The above method realizes the cascade utilization of low-grade heat energy (exhaust steam) in the smelter, greatly improves the water production rate of the demineralized water production unit, reduces the amount of concentrated water, thereby reducing the new water consumption, and the makeup water for the desalination station (the production process that provides demineralized water for the boiler) and the smelting furnace circulating water unit (the designed circulating cooling water system for a large amount of circulating water required for cooling during the production process of the furnace in the enterprise) is of high quality, improving the circulating water concentration ratio; at the same time, it realizes energy conservation and emission reduction in the treatment of salt-containing wastewater in the smelter, significantly reduces the cost of the whole plant's water treatment, and optimizes the overall water balance of the whole plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings forming a part of this application are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model. In the drawings:

[0022] Figure 1 Shows a schematic structural diagram of a smelter water balance device according to an embodiment of the present utility model.

[0023] Among them, the above-mentioned accompanying drawings include the following reference numerals:

[0024] 10. Power generation unit; 11. Generator; 12. High-pressure steam supply unit for power generation; 121. Drum; 122. Heating unit; 13. Power station circulating water unit; 20. Demineralized water production unit; 21. First LTE low-temperature thermal evaporation device; 22. First condenser; 23. Mixed ion exchanger; 30. Salty wastewater treatment unit; 31. Pulping unit; 32. Second LTE low-temperature thermal evaporation device; 33. Second condenser; 34. Solid-liquid separation unit; 35. Evaporation crystallization device; 40. Furnace body circulating water unit; 50. Deaerator. Detailed implementation mode

[0025] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present utility model will be described in detail below with reference to the drawings and in combination with the embodiments.

[0026] As described in the background art section, in existing smelters, water treatment mostly uses membrane methods. On the one hand, membrane treatment has high requirements for influent water, complex pretreatment, long process, requires adding various chemicals during operation, frequent cleaning of chemicals such as acids and alkalis in daily use, and high operating costs. Generally, the membrane components need to be replaced every 3 to 5 years. On the other hand, the water production rate of the membrane method system is less than 70%, and the amount of concentrated water is high, resulting in an increased load on downstream wastewater treatment and serious waste of water resources. At the same time, there is a lot of steam in the non-ferrous metal smelting industry, and the overall steam utilization rate is relatively low. For example, the exhausted steam (about 60°C - 70°C) after steam power generation still has a lot of latent heat of vaporization. Usually, industrial circulating cooling water is required for condensation. After steam-water heat exchange, the heat enters the circulating cooling return water and is then released into the air through the cooling tower, and the latent heat is not effectively utilized. In order to solve the problems of excessive water consumption and low steam utilization rate in existing smelters, the present utility model provides a water balance device for smelters.

[0027] In a typical embodiment, as Figure 1 shown, the water balance device for smelters provided by this application includes a power generation unit 10, a demineralized water production unit 20, a salty wastewater treatment unit 30, and a smelting furnace; wherein,

[0028] The power generation unit 10 includes a generator 11, and the generator 11 has an exhausted steam outlet;

[0029] The demineralized water production unit 20 includes a first LTE low-temperature thermal evaporation device 21, a first condenser 22, and a mixed ion exchanger 23. The first LTE low-temperature thermal evaporation device 21 has a first exhaust steam inlet, a first exhaust steam condensation port, a softened water inlet, and a first secondary steam outlet. The first exhaust steam inlet is connected to the exhaust steam outlet. The first LTE low-temperature thermal evaporation device 21 is used to perform low-temperature thermal evaporation on the softened water B entering from the softened water inlet with the exhaust steam A entering from the first exhaust steam inlet to form the first secondary steam. The first condenser 22 has a first secondary steam inlet and a first condensate outlet, and the first secondary steam inlet is connected to the first secondary steam outlet. The mixed ion exchanger 23 has its inlet connected to the first condensate outlet.

[0030] The salt-containing wastewater treatment unit 30 includes a pulping unit 31, a second LTE low-temperature thermal evaporation device 32, and a second condenser 33. The pulping unit 31 has a salt-containing wastewater inlet (for introducing salt-containing wastewater C), a seed inlet (for introducing seed adsorbent D), and a salt-containing wastewater slurry outlet. The second LTE low-temperature thermal evaporation device 32 has a second exhaust steam inlet, a second exhaust steam condensation port, a salt-containing wastewater slurry inlet, a second secondary steam outlet, and a concentrated water outlet. The second exhaust steam inlet is connected to the exhaust steam outlet, and the salt-containing wastewater slurry inlet is connected to the salt-containing wastewater slurry outlet. The second LTE low-temperature thermal evaporation device 32 is used to perform low-temperature thermal evaporation on the salt-containing wastewater slurry E entering from the salt-containing wastewater slurry inlet with the exhaust steam A entering from the second exhaust steam inlet to form the second secondary steam and concentrated water. The second condenser 33 has a second secondary steam inlet and a second condensate outlet, and the second secondary steam outlet is connected to the second secondary steam inlet.

[0031] The smelting furnace is equipped with a furnace body circulating water unit 40, and both the first condensate outlet and the second condensate outlet are connected to the furnace body circulating water unit 40.

[0032] During the actual operation of the above device, the exhausted steam A discharged from the generator 11 enters the first LTE low-temperature thermal evaporation device 21 and the second LTE low-temperature thermal evaporation device 32 respectively, and performs low-temperature thermal evaporation treatment on the softened water B and the salt-containing wastewater slurry E. During this process, the exhausted steam is transformed into exhausted steam condensate, and the softened water forms the first secondary steam F through low-temperature thermal evaporation treatment, and then forms the first condensate G after being condensed by the first condenser 22. Part of the first condensate forms desalted water H after being treated by the mixed ion exchange device 23; the salt-containing wastewater slurry E forms the second secondary steam I and the concentrated water J remaining after evaporation through low-temperature thermal evaporation treatment. The second secondary steam forms the recyclable second condensate K after being condensed by the second condenser 33; the remaining part of the first condensate and the second condensate can be directly used as the circulating water of the smelting furnace body and introduced into the furnace body circulating water unit 40 for recycling. It should be noted that the salt-containing wastewater slurry is actually obtained by adjusting the slurry of the salt-containing wastewater with the seed adsorbent entering through the seed inlet, aiming to achieve better water separation during the LTE low-temperature thermal evaporation process and the solid-liquid separation process of the concentrated water. During actual operation, the seeds can be adjusted according to the salt content of the wastewater, and calcium sulfate or the like can be used as the seeds to participate in the slurry adjustment.

[0033] Applying the technical solution of the present utility model, the overall water balance of the smelting plant is optimized by using the LTE low-temperature thermal evaporation device. Specifically: the present utility model realizes the reduction in quantity and improvement in quality of the demineralized water production unit and the zero discharge of the salt-containing wastewater treatment unit by applying the LTE low-temperature thermal evaporation device, thereby optimizing the overall water balance of the smelting plant. This device utilizes the exhausted steam of the generator, and through evaporation and condensation by the LTE low-temperature thermal evaporation device, distilled water several times the amount of the heating steam is obtained, and the wastewater is significantly reduced in quantity and approaches zero discharge. The above method realizes the cascaded utilization of the low-grade heat energy (exhausted steam) in the smelting plant, greatly improves the water production rate of the demineralized water production unit, reduces the amount of concentrated water, thereby reducing the consumption of fresh water, and the makeup water for the desalination station and the smelting furnace circulating water unit is of high quality, improving the circulating water concentration ratio; at the same time, it realizes the energy conservation and emission reduction in the treatment of the salt-containing wastewater in the smelting plant, significantly reduces the cost of the whole plant's water treatment, and the overall water balance of the whole plant is optimized.

[0034] In summary, the present utility model effectively solves the problems of low utilization rate of steam heat energy, high fresh water consumption, poor water treatment stability and high operation cost in the existing technology of smelting plants.

[0035] To make the slurry adjustment more uniform and more conducive to subsequent water treatment, preferably, the above-mentioned slurry-making unit 31 is also provided with a softened chemical inlet, a scale inhibitor inlet, etc., which is convenient for adding softened chemicals, scale inhibitors, etc. Preferably, the above-mentioned slurry-making unit 31 is also provided with a pH regulator inlet for adding a pH regulator (such as sulfuric acid) to adjust its pH value.

[0036] The above-mentioned softened water includes but is not limited to: groundwater, surface water, reclaimed water in cities, seawater, natural precipitation, etc.

[0037] To enable further utilization of the concentrated water treated by the second LTE low-temperature thermal evaporation device 32, in a preferred embodiment, as Figure 1 shown, the saline wastewater treatment unit 30 further includes a solid-liquid separation unit 34 and an evaporation crystallization device 35. The solid-liquid separation unit 34 has a concentrated water inlet, an overflow outlet, and an underflow outlet. The concentrated water inlet is connected to the concentrated water outlet, and the underflow outlet is connected to the seed inlet of the slurrying unit 31; the evaporation crystallization device 35 has an overflow inlet, an evaporation crystallization mother liquor outlet, and a crystal salt outlet. The evaporation crystallization mother liquor outlet is connected to the saline wastewater slurry inlet of the second LTE low-temperature thermal evaporation device 32. With such a setting, the concentrated water J treated by the second LTE low-temperature thermal evaporation device 32 can achieve solid-liquid separation in the solid-liquid separation unit 34 to form an underflow L and an overflow M. The underflow L is enriched with insoluble or slightly soluble salts, such as calcium salts (such as gypsum), etc., and can be returned to the seed inlet to re-slurry new wastewater; the overflow M is often enriched with soluble salts, such as sodium salts, etc. The overflow M further undergoes evaporation crystallization in the evaporation crystallization device 35 to recover the sodium salt N, and the evaporation crystallization mother liquor O can be returned to the second LTE low-temperature thermal evaporation device 32 for low-temperature thermal evaporation, achieving the purpose of further treating wastewater, increasing the water recovery rate, and zero discharge of wastewater.

[0038] Preferably, the solid-liquid separation unit 34 is a thickener.

[0039] The exhausted steam condensate obtained by the above device and the desalted water discharged from the mixed ion exchanger 23 have a lower salinity. To better utilize this part of water, in a preferred embodiment, the above device further includes a deaerator 50, whose inlet is connected to the first exhausted steam condensate port (for discharging the first exhausted steam condensate P), the outlet of the mixed ion exchanger 23, and the second condensate outlet (for discharging the second exhausted steam condensate Q). After being treated by the deaerator 50, the content of oxide impurities in the above exhausted steam condensate and desalted water is lower, and it can be further reused as high-quality water in processes with higher water quality requirements in the smelter. For example, preferably, the power generation unit 10 further includes a high-pressure steam supply unit 12 for power generation, whose inlet is connected to the outlet of the deaerator 50, and the outlet is connected to the generator 11. With such a setting, the deoxygenated water with better water quality can be returned to the power generation unit 10 to produce high-pressure steam R for power generation. In addition, the above generator 11 is a high-pressure steam generator. Here, the pressure of the high-pressure steam is usually greater than 6 MPa, and the temperature is usually > 460 °C, which is well-known in the power generation field. After power generation, low-pressure steam S can be obtained, with a pressure usually of 0.1 - 1 MPa and a temperature usually of 100 - 180 °C, which is well-known in the power generation field. The low-pressure steam can be sent to the hydrometallurgy process or other chemical processes, which will not be elaborated here.

[0040] In a preferred embodiment, the high-pressure steam supply unit 12 includes: a steam drum 121 having a water inlet and a high-pressure steam outlet for power generation, the water inlet being connected to the outlet of the deaerator 50, and the high-pressure steam outlet for power generation being connected to the generator 11; a heating unit 122 for heating the deaerated water in the steam drum 121 to obtain high-pressure steam for power generation. Exemplarily, the heating unit 122 is a boiler. As the heating unit 122, the boiler can use the high-temperature flue gas from the smelting furnace as a heat source, which is usually about 1200 °C, and the flue gas temperature can be reduced to about 350 °C after heating the deaerated water. In the specific implementation process, the boiler can be connected to the steam drum so that high-pressure steam enters the steam drum. After the outlet of the deaerator is connected to the steam drum, a pipeline can also be provided between the steam drum and the boiler so that the deaerated water enters the boiler, is heated, and then returns to the steam drum.

[0041] In a preferred embodiment, the power generation unit 10 further includes a power station circulating water unit 13 for supplying circulating water as a refrigerant to the first condenser 22 and the second condenser 33. The power generation unit 10 usually has a power station circulating water unit. Using this part of the circulating water as the refrigerant for the first condenser 22 and the second condenser 33 is also beneficial to further improving the overall plant water balance.

[0042] In a preferred embodiment, the first LTE low-temperature thermal evaporation device 21 and the second LTE low-temperature thermal evaporation device 32 are each independently selected from 1 to 20 effects in series. Using a multi-effect LTE low-temperature thermal evaporation device can further increase the amount of secondary steam, which has a more beneficial promoting effect on the water treatment efficiency. Preferably, it is 2 to 20 effects in series. At this time, the secondary steam generated in the previous effect is used as the heat source for the next effect to continue evaporation and heat exchange, and the steam is cooled to condensate. The temperature difference between each effect is 3 °C to 8 °C, and the temperature of the secondary steam in the last effect is ≤ 50 °C. The LTE device mainly includes preheating, distillation, and condensation. In the evaporation device, there is indirect steam-water heat exchange, the steam flows in the tube side, and the water is sprayed outside the tube to form a thin film. During the LTE low-temperature thermal evaporation process, the concentration ratio is related to its water quality and can be 2 to 1000 times; the condensate is the liquid after the waste steam is condensed by the raw water, and the water quality is desalted water; the product water is the secondary steam, and after it is condensed by the condenser, the conductivity is ≤ 50 μS / cm; the concentrated water controls the salt content ≤ 300 g / L; the secondary steam condensation uses circulating water cooling, and the circulating cooling feed water temperature ≤ 35 °C.

[0043] In the specific implementation process, 10. The smelter water balance device according to any one of claims 1 to 3, characterized in that the first LTE low-temperature thermal evaporation device 21 and the second LTE low-temperature thermal evaporation device 32 are each independently configured with a vacuum pump. By using a vacuum pump, negative pressure can be created initially and non-condensable gases can be pumped out during operation.

[0044] The above-mentioned device realizes the cascade utilization of steam thermal energy in the smelter, greatly improves the water production rate, optimizes the water production quality, reduces the discharge of concentrated water, sharply reduces the consumption of fresh water, realizes energy conservation and emission reduction in the whole plant's wastewater treatment, significantly reduces the cost of the whole plant's water treatment, and optimizes the water balance of the whole plant. This method can be widely applied to production enterprises such as non-ferrous smelters, waste incineration power plants, thermal power plants, steel plants, chemical plants, etc. that have heat sources such as exhausted steam and need to treat industrial wastewater, and is applicable to new construction or renovation projects.

[0045] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0046] Embodiment 1

[0047] A certain copper smelter processes 960,000 tons of copper concentrate annually. The existing demineralized water station in the plant area adopts a process flow of multi-media filtration + reverse osmosis + mixed ion exchanger, and the treatment scale is 65 t / h; the wastewater advanced treatment station mainly treats the liquid after the neutralization of waste acid, and the water quality category is high-salt and high-calcium wastewater, with a water volume of 500 m 3 / d, and adopts a process of two-stage softening + ultrafiltration + two-stage reverse osmosis + MED evaporation crystallization. After optimization and improvement, the demineralized water station is transformed to adopt the LTE low-temperature thermal method process to replace the pretreatment + reverse osmosis facilities of the demineralized water station, and the wastewater advanced treatment station is transformed to adopt the LTE low-temperature thermal method process to replace the two-stage softening + membrane method treatment process.

[0048] After the transformation, the device shown in Figure 1 is used for the overall water balance of the whole plant. Specifically as follows: The detailed steps of the treatment process of the demineralized water production unit are as follows: First step, send the produced fresh water to the LTE low-temperature thermal evaporation device for circulating spraying; Second step, introduce the exhausted steam of the generator into the LTE low-temperature thermal evaporation device for steam-water heat exchange, and the produced fresh water is distilled and concentrated, and secondary steam is produced; Third step, the exhausted steam is cooled to condensate water by the produced fresh water in the LTE low-temperature thermal evaporation device, and the water quality is demineralized water, which is pumped to the deaerator for reuse; Fourth step, the secondary steam enters the condenser and is cooled to pure water by the external circulating cooling water; Fifth step, part of the pure water is pumped to the mixed ion exchanger for reaction to prepare demineralized water to supplement the deaerator, and the remaining pure water is supplemented to the metallurgical furnace body circulating water system.

[0049] In this embodiment, the total amount of exhausted steam from the waste heat power station is 75 t / h, of which 5 t / h is used for the steam consumption of the transformed wastewater advanced treatment station, and the remaining 70 t / h is all used for the preparation of pure water in the demineralized water production unit. The treated produced fresh water volume is 68 t / h, the produced pure water volume is 64.5 t / h, the conductivity ≤ 10 μs / cm, the produced concentrated water volume is 3.5 t / h, of which 45 t / h is sent to the mixed ion exchanger for treatment, 24 t / h is used as the supplementary water for the furnace body circulating water, and the concentrated water is used for processes such as slag beneficiation or slag slow cooling.

[0050] Compared with the original membrane method for preparing pure water: (1) For the same scale of newly produced water, the output of pure water has increased significantly, from the original 45 t / h to 64.5 t / h, and the water production rate has increased by 43.33%; (2) The quality of the produced water is better, and the conductivity of the produced water is ≤ 10 μs / cm; (3) The concentration ratio is as high as 20 times, and the amount of concentrated water has been greatly reduced, from the original 20 t / h to 3.5 t / h, a year-on-year reduction of 82.5%; (4) The utilization rate of the waste steam heat energy in the waste heat power station has been increased to 65%; (5) The concentration ratio of the circulating water in the furnace body has been greatly increased, from the original 6 times to more than 10 times. While the make-up water volume has decreased sharply, zero discharge has been achieved, which further ensures the safe operation of the process equipment.

[0051] The detailed steps of the improved deep treatment process for production wastewater are as follows: After the salt-containing wastewater is homogenized and adjusted, it is pumped to the pulping tank. In the pulping tank, sulfuric acid is added to adjust the pH of the wastewater to about 6, and a seed adsorbent is added and mixed for pulping to form the pre-evaporation liquid, which is then pumped to the LTE low-temperature thermal evaporation device for circulating spraying. Multiple heat exchanges are carried out between the outside of the heat exchange tubes and the steam inside the tubes. The wastewater evaporates to produce secondary steam, and the remaining concentrated water is discharged for solid-liquid separation. The overflow water is discharged to the evaporation and crystallization system for further treatment, and the underflow is filtered and transported outside. The heat source is the waste steam from the waste heat power station, with a temperature of about 65°C. While the steam inside the tubes exchanges heat with the wastewater outside the tubes, the steam inside the tubes is condensed into a liquid. The wastewater outside the tubes absorbs the latent heat of the steam inside the tubes to generate secondary steam, which is reused as the heat source for the next-effect evaporator until the last effect. The secondary steam from the last effect enters the condenser and is condensed by the circulating cooling water. The primary steam condensate is directly sent back to the deaerator of the boiler. The condensate produced from the secondary steam is about 450 m3 / d, and the conductivity of the produced water is ≤ 30 μs / cm, which is sent to the circulating water as make-up water; the remaining 50 m3 / d of concentrated water enters the triple-effect evaporation and crystallization after softening treatment.

[0052] Compared with the original membrane method for preparing pure water: (1) For the same scale of salt-containing wastewater treatment, the output of pure water has increased significantly, from the original 410 t / d to 460 t / d, and the water production rate has increased by 12%; (2) The quality of the produced water is better, and the conductivity of the produced water is ≤ 30 μs / cm; (3) The concentration ratio is as high as 12 times, and the amount of concentrated water has decreased sharply, from the original 90 t / d to 40 t / d, a year-on-year reduction of 56%; (4) The utilization rate of the waste steam heat energy in the waste heat power station has been increased to 65%; (5) The concentration ratio of the circulating water has been greatly increased, from the original 6 times to more than 10 times. While the make-up water volume has decreased sharply, zero discharge has been achieved.

[0053] From the above description, it can be seen that the above embodiments of the present utility model have achieved the following technical effects:

[0054] 1. Realize the cascade utilization of low-grade heat energy (waste steam) in the smelter, greatly improve the water production rate of the demineralized water station, reduce the amount of concentrated water, and thus reduce the new water consumption. Compared with before the transformation, the new water consumption has been reduced by 500 m 3 / d; and the make-up water for the demineralized water station and the circulating water system is of high quality, with a conductivity ≤ 30 μs / cm, which increases the concentration ratio of the circulating water and significantly reduces the blowdown volume of the circulating water;

[0055] 2. The process flow is simple and the treatment efficiency is high, achieving energy conservation and emission reduction in the wastewater treatment of the smelter, significantly reducing the cost of the whole plant's water treatment, and optimizing the overall water balance of the plant. After the transformation of the water treatment station, the operating cost is reduced by 87%, and the operating cost of the saline wastewater treatment is reduced by 45%.

[0056] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A horizontal water balance device for a smelter, comprising a power generation unit (10), a demineralized water production unit (20), a saline wastewater treatment unit (30), and a smelting furnace; characterized in that, The power generation unit (10) includes a generator (11), and the generator (11) has an exhaust steam outlet; The demineralized water production unit (20) includes: A first LTE low-temperature thermal evaporation device (21), having a first exhaust steam inlet, a first exhaust steam condensation port, a softened water inlet, and a first secondary steam outlet. The first exhaust steam inlet is connected to the exhaust steam outlet. The first LTE low-temperature thermal evaporation device (21) is used to perform low-temperature thermal evaporation on the softened water entering from the softened water inlet by the exhaust steam entering from the first exhaust steam inlet to form first secondary steam; A first condenser (22), having a first secondary steam inlet and a first condensate outlet, and the first secondary steam inlet is connected to the first secondary steam outlet; A mixed ion exchanger (23), whose inlet is connected to the first condensate outlet; The saline wastewater treatment unit (30) includes: A pulping unit (31), having a saline wastewater inlet, a seed crystal inlet, and a saline wastewater slurry outlet; A second LTE low-temperature thermal evaporation device (32), having a second exhaust steam inlet, a second exhaust steam condensation port, a saline wastewater slurry inlet, a second secondary steam outlet, and a concentrated water outlet. The second exhaust steam inlet is connected to the exhaust steam outlet. The saline wastewater slurry inlet is connected to the saline wastewater slurry outlet. The second LTE low-temperature thermal evaporation device (32) is used to perform low-temperature thermal evaporation on the saline wastewater slurry entering from the saline wastewater slurry inlet by the exhaust steam entering from the second exhaust steam inlet to form second secondary steam and concentrated water; A second condenser (33), having a second secondary steam inlet and a second condensate outlet, and the second secondary steam outlet is connected to the second secondary steam inlet; The smelting furnace is configured with a furnace body circulating water unit (40), and both the first condensate outlet and the second condensate outlet are connected to the furnace body circulating water unit (40).

2. The smelter water balance device according to claim 1, characterized in that, The saline wastewater treatment unit (30) further includes: A solid-liquid separation unit (34), having a concentrated water inlet, an overflow outlet, and an underflow outlet. The concentrated water inlet is connected to the concentrated water outlet, and the underflow outlet is connected to the seed crystal inlet of the pulping unit (31); An evaporation crystallization device (35), having an overflow inlet, an evaporation crystallization mother liquor outlet, and a crystal salt outlet. The evaporation crystallization mother liquor outlet is connected to the saline wastewater slurry inlet of the second LTE low-temperature thermal evaporation device (32).

3. The smelter water balance device according to claim 2, wherein The solid-liquid separation unit (34) is a thickener.

4. The smelter water balance device according to any one of claims 1 to 3, characterized in that, It further includes: An deaerator (50), whose inlet is connected to the first exhaust steam condensation port, the outlet of the mixed ion exchanger (23), and the second condensate outlet.

5. The smelter water balance device according to claim 4, characterized in that, The power generation unit (10) further includes a high-pressure steam supply unit (12) for power generation, whose inlet is connected to the outlet of the deaerator (50), and the outlet is connected to the generator (11).

6. The smelter water balance device according to claim 5, characterized in that, The high-pressure steam supply unit (12) includes: A steam drum (121) having a water inlet and a high-pressure steam outlet for power generation, the water inlet being connected to the outlet of the deaerator (50), and the high-pressure steam outlet for power generation being connected to the generator (11); A heating unit (122) for heating the deaerated water in the steam drum (121) to obtain high-pressure steam for power generation.

7. The smelter water balance device according to claim 6, wherein, The heating unit (122) is a boiler.

8. The smelter water balance device according to any one of claims 1 to 3, characterized in that, The power generation unit (10) further includes a power station circulating water unit (13) for supplying circulating water as a refrigerant to the first condenser (22) and the second condenser (33).

9. The smelter water balance device according to any one of claims 1 to 3, characterized in that, The first LTE low-temperature thermal evaporation device (21) and the second LTE low-temperature thermal evaporation device (32) are each independently selected from 1 to 20 effects in series.

10. The smelter water balance device according to any one of claims 1 to 3, characterized in that, The first LTE low-temperature thermal evaporation device (21) and the second LTE low-temperature thermal evaporation device (32) are each independently configured with a backing vacuum pump.

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