Hydrogen energy new material production wastewater reduction treatment method

Abstract

The application discloses a hydrogen energy new material production wastewater reduction treatment method, which comprises the following steps: (1) stirring and blowing: adding alkali liquor into the wastewater obtained from hydrogen energy new material production, and performing hot air blowing to make the production raw materials and intermediates in the wastewater regenerate and precipitate; (2) solid-liquid separation: recycling the slurry obtained through solid-liquid separation to a production workshop for reuse, and making the treated wastewater enter an extraction equipment; (3) extraction; (4) cooling crystallization; (5) evaporation and dehydration: respectively performing evaporation and dehydration on sodium sulfate solution and sodium chloride solution, separating out evaporation condensate and evaporation concentrated solution, and collecting crude sodium sulfate and crude sodium chloride; (6) centrifugal drying: obtaining refined sodium sulfate after centrifugal drying of the crude sodium sulfate, and obtaining refined sodium chloride after drying. The application has high treatment efficiency and good economic benefit, can effectively treat the high-concentration complex wastewater, separate the salt and nitre in the wastewater, and obtain white and high-purity sodium sulfate and sodium chloride.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and in particular to a hydrogen energy new material production wastewater reduction treatment method. BACKGROUND

[0002] In a hydrogen energy new material production process, complex wastewater with high salt (mass fraction of sodium sulfate and sodium chloride in total wastewater mass > 10%), high organic matter (concentration > 10000 mg / L, calculated as COD), and high ammonia nitrogen (concentration > 3000 mg / L) is generated, which is difficult to treat. In particular, the removal of organic matter and ammonia nitrogen needs to be combined with salt and nitrate separation, which is a difficult problem that needs to be solved in the field of material wastewater treatment, and there are few reports in the prior art.

[0003] Traditional high-organic-matter, high-ammonia-nitrogen, and salt-containing wastewater is directly disposed as waste liquid, but some resources such as salt can be recycled from the production end. For the above-mentioned wastewater, there are many treatment methods for single pollution factors, such as the removal of high-concentration organic matter, which can use electro-catalytic oxidation and wet oxidation technology. However, the former is greatly affected by ammonia nitrogen, and the efficiency of removing organic matter will be reduced. The latter has safety hazards and high operating costs, so the method of removing organic matter and ammonia nitrogen needs to be combined with salt and nitrate separation technology, and high-purity sodium sulfate and sodium chloride with white appearance are extracted to achieve maximum reduction.

[0004] In order to achieve the maximum reduction of wastewater from hydrogen energy new material production, it is of great significance to promote the industrialization production and green development of hydrogen energy new material. SUMMARY

[0005] In view of the above defects of the prior art, the technical purpose of the present application is to provide a hydrogen energy new material production wastewater reduction treatment method with high treatment efficiency and good economic benefit.

[0006] In order to solve the above problems, the present application provides the following technical scheme: a hydrogen energy new material production wastewater reduction treatment method of the present application, comprising the following steps:

[0007] (1) Stirring and stripping: adding alkali liquor to the wastewater obtained from hydrogen energy new material production, and performing hot air stripping to regenerate and precipitate the production raw materials and intermediates in the wastewater, and collecting the ammonia gas through dilute sulfuric acid absorption;

[0008] (2) Solid-liquid separation: after the alkali stirring and stripping of step (1), the slurry obtained by solid-liquid separation is recycled to the production workshop for reuse, and the treated wastewater enters the extraction equipment;

[0009] (3) extraction: a certain amount of extractant is added into the extraction equipment, and is fully mixed with the wastewater to form two phases, and then the oil phase is subjected to rectification to recover the extractant for reuse, and the water phase enters the cooling crystallizer;

[0010] (4) cooling crystallization: the wastewater is circulated in the external cooler and the cooling crystallizer by using an axial flow pump, and the cooled wastewater is crystallized in the crystallizer to separate the solid and the liquid, and the sodium sulfate decahydrate is recovered, and the sodium sulfate solution is obtained by dissolving the sodium sulfate decahydrate in water, and the pH of the crystallization mother liquor is adjusted to neutral to obtain the sodium chloride solution;

[0011] (5) evaporation and dehydration: the sodium sulfate solution and the sodium chloride solution are subjected to evaporation and dehydration respectively, and the evaporation condensate and the evaporation concentrated solution are separated, and the sodium sulfate crude salt and the sodium chloride crude salt are obtained, and the evaporation condensate is reused as production make-up water or is discharged after biological treatment;

[0012] (6) centrifugal drying: the sodium sulfate crude salt is subjected to centrifugal drying to obtain refined sodium sulfate, and the sodium chloride crude salt is washed, centrifuged and dried to obtain refined sodium chloride.

[0013] Further, in step (1), the mass fraction of sodium sulfate and sodium chloride in the wastewater is ≥10% of the total mass of the wastewater, the COD is 10000-80000 mg / L, and the ammonia nitrogen concentration is ≥3000 mg / L.

[0014] Further, in step (1), the alkali liquor is one or a combination of soluble alkali metal hydroxide and soluble carbonate.

[0015] Further, in step (1), the mass ratio of the soluble alkali metal hydroxide to the organic matter (calculated by COD) is 0.4-2.1, the mass ratio of the soluble carbonate to the organic matter (calculated by COD) is 0.5-2.7, and the reaction time is 0.25-3.0 h.

[0016] Further, in step (1), the mass ratio of the soluble alkali metal hydroxide to the organic matter (calculated by COD) is 1.0-2.0, the reaction time is 0.5-1.5 h, the material temperature maintained by the hot air is 70-90℃, and the gas-liquid ratio is 10-20 L / (L﹒min).

[0017] Further, in step (3), the extractant is one or a combination of benzene and toluene, the extraction stages can be selected from 1-3 stages, and the volume flow ratio of the extractant to the water phase is 1-2:1.

[0018] Further, in step (4), the temperature of the cooled wastewater is controlled to be -5-10℃, and the temperature of the cooling crystallizer is controlled to be -2-3℃.

[0019] Further, in step (5), the reuse ratio of the condensed liquid is 70-95% (w / w), the evaporation concentration ratio of the sodium sulfate solution is 2-15:1, and the evaporation concentration ratio of the sodium chloride solution is 2-12:1.

[0020] Further, in step (6), the washing liquid for the crude sodium chloride salt is a combination of one or both of saturated sodium chloride and methanol, and the amount of the washing liquid is determined according to the amount of the crude sodium chloride salt, and the washing level is 1-3 levels.

[0021] The reagents used in the present application are commercially available.

[0022] The present application has the following beneficial effects:

[0023] The present application has high treatment efficiency and good economic benefits, and can not only effectively treat such high-concentration complex wastewater, but also separate the salt and nitrate to obtain white and high-purity sodium sulfate and sodium chloride.

[0024] Compared with the prior art, the present application has the following advantages: (1) The method comprehensively considers the removal of organic matter and ammonia nitrogen and the separation of salt and nitrate, and uses a series of economic and efficient methods such as hot air stripping, solid-liquid separation, extraction, cooling crystallization, evaporation, washing, centrifugation, and drying to obtain white and high-purity refined sodium sulfate and refined sodium chloride, the slurry after solid-liquid separation is reused in the front-end production, the oil phase produced by extraction is reused after rectification and recovery, and the condensed liquid is reused or biologically treated, so that the whole process achieves maximum reduction, which is of great significance for promoting the industrialized production of hydrogen energy new materials and green development.

[0025] (2) The combined treatment process of the present application achieves maximum reduction and generates additional value. It breaks through the short board of electro-catalytic oxidation and wet oxidation technology, and skillfully combines traditional technologies, while realizing the removal of organic matter, ammonia nitrogen and the separation of salt and nitrate. First, alkali is added, and hot air stripping is used to realize the regeneration and precipitation of production raw materials and intermediates, improve the utilization rate of raw materials, reduce the concentration of organic matter, realize ammonia removal, and facilitate the subsequent separation of salt and nitrate, and evaporate to obtain refined salt. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The process flow diagram of the present application is shown in the figure. DETAILED DESCRIPTION

[0027] The concept, specific structure and technical effects of the present application will be further described below with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the present application.

[0028] The present application will be further described below by way of examples, but the present application is not limited to the scope of the examples.

[0029] Example 1

[0030] As Figure 1 shown, the wastewater obtained from the production of a certain hydrogen energy new material, the mass fraction of sodium sulfate and sodium chloride accounts for 42.5% of the total mass of the wastewater, the COD is 36575 mg / L, the ammonia nitrogen is 18200 mg / L, and the pH is 0.69.

[0031] The hydrogen energy new material production wastewater reduction treatment method provided by the application comprises the following steps:

[0032] (1) Stirring and stripping: sodium hydroxide solution is added to the hydrogen energy new material wastewater, the ratio of sodium hydroxide to organic matter (calculated by COD) is 1.7, hot air is used to control the material temperature to 90 DEG C, the gas-liquid ratio is 15 L / (L.min), and the stirring reaction is carried out for 1.0 h.

[0033] (2) Solid-liquid separation: after filtration, the slurry mass accounts for 0.83% of the treated water volume, the quality meets the production requirements, is reused to the front-end production system, the COD of the filtrate is 29472 mg / L, the ammonia nitrogen is 5150 mg / L, and the filtrate enters the first-stage extraction equipment.

[0034] (3) Extraction: toluene is added to the first-stage extraction equipment in a volume ratio of 1:1 (water phase: oil phase), the equipment is started to fully mix the two phases, and then the two phases are separated, the oil phase is reused after rectification to recover toluene, the water phase enters the second-stage extraction equipment, toluene is added to the second-stage extraction equipment in a volume ratio of 1:0.5 (water phase: oil phase), the equipment is started to fully mix the two phases, and then the two phases are separated, the oil phase is reused after rectification to recover toluene, the COD of the water phase is 10300 mg / L, the ammonia nitrogen is 3900 mg / L, and the water phase enters the cooling crystallizer.

[0035] (4) Cooling crystallization: the temperature of the cooling crystallizer is controlled to 1±2 DEG C, sodium sulfate crystals are obtained, the sodium sulfate crystals are dissolved and prepared into a sodium sulfate solution, and then the sodium sulfate solution enters evaporation dehydration A; the crystallization mother liquor is adjusted to neutral by hydrochloric acid to obtain a sodium chloride solution, and then the sodium chloride solution enters evaporation dehydration B.

[0036] (5) Evaporation dehydration: the sodium sulfate solution and the sodium chloride solution are respectively subjected to evaporation dehydration, the concentration ratio of the former is 10:1, the concentration ratio of the latter is 8:1, the evaporation condensate obtained from the former has a COD of 752 mg / L and an ammonia nitrogen of 91 mg / L, the evaporation condensate obtained from the latter has a COD of 460 mg / L and an ammonia nitrogen of 212 mg / L, and the evaporation condensate meets the production requirements. 90% of the evaporation condensate is reused to the production system; the obtained sodium sulfate coarse salt and sodium chloride coarse salt are respectively subjected to centrifugal drying and washing centrifugal drying treatment.

[0037] (6) centrifugal drying: the crude sodium sulfate is centrifugally separated and dried to obtain refined sodium sulfate with white appearance and sodium sulfate content of 98.4%; the crude sodium chloride is washed by saturated sodium chloride brine in two stages (the adding ratio is based on the immersion of the crude sodium chloride), and after washing, centrifugal separation and drying, refined sodium chloride with white appearance and sodium chloride content of 97.2% is obtained.

[0038] Example 2

[0039] The difference between Example 2 and Example 1 is that:

[0040] In step (1), the hot air controls the material temperature to be 70 DEG C. After filtration, the slurry mass is 1.01% of the water treatment amount, which meets the requirements of recycling to the production end;

[0041] In step (2), the two-stage extraction is changed to one-stage extraction, and the volume ratio of toluene once added is 1:1.5 (water phase: oil phase). After phase separation, the COD of the water phase is 12800 mg / L, and the ammonia nitrogen is 3750 mg / L. Finally, the quality of the evaporation condensate meets the recycling requirements, and 80% of the evaporation condensate is recycled to the production system. The refined sodium sulfate has white appearance and effective content of 97.6%, and the refined sodium chloride has white appearance and effective content of 96.6%.

[0042] Example 3

[0043] The difference between Example 3 and Example 1 is that:

[0044] In step (5), the crude sodium chloride is washed by methanol in two stages, and the amount of each stage is based on the immersion of the crude sodium chloride. After drying, refined sodium chloride with white appearance and sodium chloride content of 96.8% is obtained.

[0045] Example 4

[0046] The wastewater obtained from the production of a certain hydrogen energy new material contains 35.0% of sodium sulfate and sodium chloride by mass fraction, and the total mass of the wastewater is 29475 mg / L, the ammonia nitrogen is 10500 mg / L, and the pH is 0.66.

[0047] The hydrogen energy new material production wastewater reduction treatment method of the application comprises the following steps:

[0048] In step (1), stirring stripping: sodium carbonate solution is added to the hydrogen energy new material wastewater, the ratio of sodium carbonate to organic matter (calculated by COD) is 2.1, the hot air controls the material temperature to be 90 DEG C, the gas-liquid ratio is 18 L / (L·min), and the stirring reaction is carried out for 1.5 h.

[0049] In step (2), solid-liquid separation: after filtration, the slurry mass is 1.27% of the treated water volume, and its quality meets the production requirements, and is reused to the front-end production system, and the filtrate enters the first-stage extraction equipment.

[0050] In step (3), extraction: toluene is added to the first-stage extraction equipment at a volume ratio of 1:1 (water phase: oil phase), the equipment is started to fully mix the two phases, and then the oil phase is separated, toluene is recovered by rectification and reused, and the water phase enters the second-stage extraction equipment, to which toluene is added at a volume ratio of 1:1 (water phase: oil phase), the equipment is started to fully mix the two phases, and then the oil phase is separated, toluene is recovered by rectification and reused, the water phase has a COD of 9800 mg / L and an ammonia nitrogen of 2600 mg / L, and enters the cooling crystallizer.

[0051] In step (4), cooling crystallization: the cooling crystallizer is controlled at a temperature of 1±2℃, and sodium sulfate crystals are obtained, which are dissolved to prepare a sodium sulfate solution and then enter evaporation dehydration A; the crystallization mother liquor is adjusted to neutral by hydrochloric acid to obtain a sodium chloride solution which enters evaporation dehydration B.

[0052] In step (5), evaporation dehydration: the sodium sulfate solution and the sodium chloride solution are respectively subjected to evaporation dehydration, the former has a concentration ratio of 10:1, and the latter has a concentration ratio of 8:1, the evaporation condensate obtained from the former has a COD of 613 mg / L and an ammonia nitrogen of 65 mg / L, and the evaporation condensate obtained from the latter has a COD of 526 mg / L and an ammonia nitrogen of 82 mg / L, which meet the production requirements. 95% of the evaporation condensate is reused to the production system; the obtained sodium sulfate crude salt and sodium chloride crude salt are respectively subjected to centrifugal drying and washing centrifugal drying treatment.

[0053] In step (6), centrifugal drying: after centrifugal separation and drying, the sodium sulfate crude salt becomes refined sodium sulfate with a white appearance and a sodium sulfate content of 98.5%; the sodium chloride crude salt is washed by a first-stage saturated sodium chloride brine and a second-stage methanol, and is subjected to two-stage washing (the addition ratio is based on the immersion of the sodium chloride crude salt), and then is subjected to centrifugal separation and drying to obtain refined sodium chloride with a white appearance and a sodium chloride content of 97.4%.

[0054] Example 5

[0055] The difference between Example 5 and Example 4 is that:

[0056] In step (1), stirring stripping: sodium carbonate solution is added to the hydrogen energy new material wastewater, the ratio of sodium carbonate to organic matter (calculated by COD) is 0.4, hot air is used to control the material temperature at 90℃, the gas-liquid ratio is 18 L / (L·min), and the stirring reaction is carried out for 3 h.

[0057] In step (5), evaporation and dehydration: the sodium sulfate solution and the sodium chloride solution are respectively subjected to evaporation and dehydration, the former is concentrated at a ratio of 2:1, and the latter is concentrated at a ratio of 12:1, the evaporation condensate obtained from the former has a COD of 527 mg / L and an ammonia nitrogen of 39 mg / L, and the evaporation condensate obtained from the latter has a COD of 794 mg / L and an ammonia nitrogen of 95 mg / L, which meet the production requirements. 95% of the evaporation condensate is reused to the production system; the obtained sodium sulfate coarse salt and sodium chloride coarse salt are respectively subjected to centrifugal drying and washing and centrifugal drying treatment.

[0058] Example 6

[0059] The difference between Example 6 and Example 4 lies in that:

[0060] In step (1), stirring and stripping: sodium carbonate solution is added to the hydrogen energy new material wastewater, the ratio of sodium carbonate to organic matter (calculated by COD) is 2.1, hot air is used to control the material temperature at 90°C, the gas-liquid ratio is 18 L / (L·min), and the stirring reaction is performed for 0.25 h.

[0061] In step (5), evaporation and dehydration: the sodium sulfate solution and the sodium chloride solution are respectively subjected to evaporation and dehydration, the former is concentrated at a ratio of 15:1, and the latter is concentrated at a ratio of 2:1, the evaporation condensate obtained from the former has a COD of 705 mg / L and an ammonia nitrogen of 68 mg / L, and the evaporation condensate obtained from the latter has a COD of 583 mg / L and an ammonia nitrogen of 56 mg / L, which meet the production requirements. 95% of the evaporation condensate is reused to the production system; the obtained sodium sulfate coarse salt and sodium chloride coarse salt are respectively subjected to centrifugal drying and washing and centrifugal drying treatment.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 lies in that, in step (5), the evaporation concentration ratio of the sodium sulfate solution is 15:1, and the evaporation concentration ratio of the sodium chloride solution is 15:1, the evaporation condensate obtained from the former has a COD of 840 mg / L and an ammonia nitrogen of 104 mg / L, and the evaporation condensate obtained from the latter has a COD of 590 mg / L and an ammonia nitrogen of 189 mg / L, which meet the reuse production requirements. The refined sodium sulfate has a light yellow appearance, and the effective content is 97.3%, and the refined sodium chloride has a white appearance and an effective content of 96.4%.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 1 lies in that, in step (5), the sodium chloride coarse salt is subjected to primary washing with saturated sodium chloride brine, and the amount of the saturated sodium chloride brine is determined according to the amount of the sodium chloride coarse salt, and after drying, refined sodium chloride with a light yellow appearance and a sodium chloride content of 96.1% is obtained.

[0066] Comparative Example 3

[0067] The difference between the present comparative example and Example 1 is that in step (2), two-stage extraction is replaced by one-stage extraction, and the volume ratio of one-time addition of toluene is 1:1 (water phase: oil phase), and the COD of the water phase after phase separation is 17600 mg / L, and the ammonia nitrogen is 3800 mg / L, and finally the quality of the evaporation condensate meets the reuse requirements, and 75% of the evaporation condensate is reused to the production system; the appearance of the refined sodium chloride is light yellow, and the effective content is 95.8%.

[0068] Comparative Example 4

[0069] The difference between the present comparative example and Example 4 is that in step (1), the ratio of sodium carbonate to organic matter (calculated by COD) added to the hydrogen energy new material wastewater is 1.2, and the quality of the final evaporation condensate does not meet the reuse requirements due to the high ammonia nitrogen concentration; the appearance of the refined sodium sulfate is light yellow, and the effective content is 96.8%, and the appearance of the refined sodium chloride is light yellow, and the effective content is 94.7%.

[0070] The above detailed the preferred embodiments of the present application. It should be understood that those skilled in the art can make many modifications and changes without creative labor based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the existing technology according to the concept of the present application shall be within the protection scope determined by the claims.

Claims

1. A method for reducing the volume of wastewater from the production of new hydrogen energy materials, characterized in that: Includes the following steps: Step (1) Stirring and stripping: Add alkaline solution to the wastewater from the production of hydrogen energy new materials and perform hot air stripping to regenerate and precipitate the production raw materials and intermediates in the wastewater. At the same time, the collected ammonia gas is absorbed by dilute sulfuric acid. In the wastewater, the mass fraction of sodium sulfate and sodium chloride accounts for ≥10% of the total mass of the wastewater, the COD is 10000~80000 mg / L, and the ammonia nitrogen concentration is ≥3000 mg / L. The alkaline solution is one or a combination of two of the following: soluble alkali metal hydroxide or soluble carbonate. When the mass ratio of the soluble alkali metal hydroxide to organic matter (calculated as COD) is 1.0~2.0, the reaction time is 0.5~1.5h, the material temperature maintained by hot air is 70℃~90℃, and the gas-liquid ratio is 10~20L / (L·min). Step (2) Solid-liquid separation: After adding alkali, stirring and stripping in step (1), the slurry obtained from solid-liquid separation is recycled to the production workshop for reuse, and the treated wastewater enters the extraction equipment; Step (3) Extraction: Add a certain amount of extractant into the extraction equipment, so that it is fully mixed with the wastewater and separated into layers. The oil phase is distilled to recover the extractant and reused, while the water phase enters the cooling crystallizer. Step (4) Cooling and crystallization: The wastewater is circulated in the external cooler and cooling crystallizer by axial flow pump. The cooled wastewater crystallizes and separates solid and liquid in the crystallizer to recover sodium sulfate decahydrate and crystallization mother liquor. Sodium sulfate decahydrate is dissolved in water to obtain sodium sulfate solution. The pH of the crystallization mother liquor is adjusted to neutral to obtain sodium chloride solution. Step (5) Evaporation and dehydration: Sodium sulfate solution and sodium chloride solution are evaporated and dehydrated respectively to separate evaporation condensate and evaporation concentrate, and crude sodium sulfate salt and crude sodium chloride salt are collected. The evaporation condensate is reused as production makeup water or discharged after biological treatment to meet the standards. Step (6) Centrifugal drying: Sodium sulfate crude salt is centrifuged and dried to obtain refined sodium sulfate, and sodium chloride crude salt is washed with washing liquid, centrifuged and dried to obtain refined sodium chloride.

2. The method for reducing the volume of wastewater from hydrogen energy new material production according to claim 1, characterized in that: In step (1), when the mass ratio of the soluble alkali metal hydroxide to organic matter (calculated as COD) is 0.4~2.1 and the mass ratio of the soluble carbonate to organic matter (calculated as COD) is 0.5~2.7, the reaction time is 0.25~3.0 h.

3. The method for reducing the volume of wastewater from hydrogen energy new material production according to claim 1, characterized in that: In step (3), the extractant is one or a combination of benzene and toluene, the number of extraction stages can be selected as 1 to 3, and the volume flow ratio of extractant to aqueous phase is 1 to 2:

1.

4. The method for reducing the volume of wastewater from hydrogen energy new material production according to claim 1, characterized in that: In step (4), the temperature of the cooled wastewater is controlled at -5~10℃, and the temperature of the cooling crystallizer is controlled at -2~3℃.

5. The method for reducing the volume of wastewater from hydrogen energy new material production according to claim 1, characterized in that: In step (5), the recycling rate of the evaporated condensate is 70-95% (w / w), the evaporation concentration ratio of the sodium sulfate solution is 2-15:1, and the evaporation concentration ratio of the sodium chloride solution is 2-12:

1.

6. The method for reducing the volume of wastewater from the production of new hydrogen energy materials according to claim 1, characterized in that: In step (6), the washing solution used for crude sodium chloride is one or a combination of saturated sodium chloride and methanol. The amount of washing solution used is based on immersing the crude sodium chloride, and the washing level is 1 to 3.

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