Advanced treatment method for sucralose high-salinity wastewater

Abstract

The invention provides a method for deeply treating sucralose high-salinity wastewater, and belongs to the technical field of sewage treatment. According to the technology, secondary steam generated by an evaporation system and energy of the secondary steam are utilized, the secondary steam is pumped back through an MVR system compressor to reheat a system heater, steam reutilization is completed, primary steam energy consumption is reduced, sucralose high-salt wastewater is evaporated and concentrated, the evaporation capacity needs to reach 70% or above, and the energy consumption is reduced. And the generated concentrated solution is concentrated again in a plurality of single effects. The treatment capacity is improved by continuous production of the system, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and specifically relates to a method for deep treatment of sucralose high-salt wastewater. Background Art

[0002] In industrial production, saline wastewater containing sodium chloride and potassium chloride is often produced, such as landfill leachate wastewater, sintering ash wastewater, desulfurization wastewater, metallurgical wastewater, etc. For example, waste incineration power plants and landfills will produce a large amount of leachate wastewater in the actual production process. These leachates contain certain organic matter, ammonia nitrogen and other components, and other main components are mostly high-concentration salts. After the leachate wastewater undergoes a pre-treatment process to degrade and eliminate the organic matter, ammonia nitrogen and other components, the remaining saline solution includes sodium chloride, potassium chloride and other components. The existing technology generally uses a multi-effect evaporation method to treat these high-concentration saline wastewaters. The process flow is to preheat and then pass through a multi-effect evaporator in turn. The slurry coming out of the evaporator is centrifugally dehydrated and solid dried to obtain a mixed salt product.

[0003] The high-salt (ammonium chloride salt) and high-COD wastewater generated in the sucralose production process undergoes physical and chemical pretreatment and then evaporation pretreatment before entering the MVR and single evaporator for treatment.

[0004] For example, Chinese patent CN112225375A discloses a pretreatment method for sucralose wastewater, which comprises the following steps: (1) the sucralose wastewater is regulated in a regulating tank, treated in a coagulation sedimentation tank, and treated in a wet catalytic oxidation device in sequence; (2) the wastewater continues to enter the coagulation sedimentation tank, and 0.02-0.04% of the weight of the wastewater coagulant and 0.002-0.005% of the weight of the wastewater are added respectively, the pH value is controlled to be 6.5-7.5, and the reaction is carried out for 10-15 minutes. After the wastewater comes out, it enters the sedimentation tank, and the residence time is 1.5-2.5 hours; (3) the supernatant in the sedimentation tank is subjected to air flotation, and the scum is removed by quartz sand filtration, and the wastewater enters the membrane separation device, and the formed inorganic high-salt wastewater and organic low-salt wastewater enter the MVR evaporator respectively; (4) the evaporated condensed water enters the biochemical system, and the evaporated concentrated liquid of the inorganic high-salt wastewater returns to the regulating tank; the evaporated concentrated liquid of the organic low-salt wastewater enters the incineration device. However, this process will result in the inability to carry out continuous production, the overall processing cost is high, and the concentration and sealing performance of a single evaporator is not strong, resulting in the inability to effectively control the on-site environment.

[0005] Another example is the Chinese patent CN110803821A, which discloses a method for deep treatment of sucralose high-salt wastewater concentrate. After the concentrated liquid temperature crystallization after MVR evaporation, the high-salt wastewater is centrifuged to separate the ammonium chloride salt and the concentrate. The concentrate is heated to 80-95°C by a heat exchanger and then sent to a dehydration tower for spraying and atomization. Dry air is introduced from the lower part of the dehydration tower to exchange heat with the atomized concentrate, and the water and light components in the concentrate are taken out to form a gas phase and enter the condensation washing tower. The water and soluble light components in the gas phase are absorbed by the spray water in the washing tower to form absorption water, and the absorption water enters the sewage biochemical treatment system. The gas phase after spraying enters the tail gas collection and treatment system for treatment; the concentrated liquid dehydrated in the dehydration tower is separated again by a centrifuge to separate the ammonium chloride salt. This invention can effectively and thoroughly solve the problem of the final concentrated liquid in the treatment of high-salt and high-COD wastewater, which will greatly improve the overall chemical production level, and also meet the national environmental protection management requirements. This method also has the problem that it cannot be produced continuously and the on-site environment cannot be effectively controlled.

[0006] Therefore, it is necessary to develop a method for deep treatment of sucralose high-salt wastewater that can achieve continuous production, good airtightness, low cost, and conform to green production. Summary of the invention

[0007] Based on the deficiencies in the prior art, the present invention aims to provide a method for deep treatment of sucralose high-salt wastewater, aiming to solve the problems of the existing system being unable to produce continuously, weak airtightness of single-effect evaporation, small system processing capacity, high processing cost, environmental pollution, etc.

[0008] The technology of the present invention utilizes the secondary steam and its energy generated by the evaporation system itself, and reheats the system heater by withdrawing the secondary steam through the MVR system compressor, completing the steam reuse, reducing the primary steam energy consumption, and evaporating and concentrating the sucralose high-salt wastewater (mainly containing ammonium chloride salt). The evaporation amount must reach more than 70%, and the concentrated liquid is sent to multiple single-effect re-concentration. The system continuously produces to increase the processing capacity, and the processing capacity increases and the production cost decreases.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] The present invention provides a method for deep treatment of sucralose high-salt wastewater, comprising the following steps:

[0011] (1) The wastewater obtained in the production process of sucralose is sent to a flocculation reaction tank through a lifting pump for flocculation, and then transferred to a vertical flow sedimentation tank for sedimentation, the precipitated sludge is discharged to the sludge tank, and the supernatant overflows to the inclined tube sedimentation tank for secondary sedimentation, the sludge after the secondary sedimentation is discharged to the sludge tank, and the supernatant in the inclined tube sedimentation tank overflows to the raw water tank, completing the physical and chemical pretreatment of the high salt water;

[0012] (2) The pretreated high-salt water enters the first-effect heater from the raw water tank for heating, and then enters the first-effect separator for gas-liquid separation to obtain high-salt water after primary concentration; the high-salt water after primary concentration enters the second-effect heater for heating, and then is transported to the second-effect separator for gas-liquid separation to obtain high-salt water after secondary concentration; the high-salt water after secondary concentration enters the third-effect heater for heating, and then enters the third-effect separator for gas-liquid separation to obtain high-salt water after tertiary concentration;

[0013] (3) The high brine after tertiary concentration is transported to the single-effect 1 heater for heating, and then transported to the single-effect 1 separator for gas-liquid separation to obtain concentrated high brine; the concentrated high brine is transported from the single-effect 1 separator to the single-effect 2 heater for heating, and then transported to the single-effect 2 separator for gas-liquid separation to obtain high brine after re-concentration; the high brine after re-concentration is transported to the single-effect 3 heater for heating, and then transported to the single-effect 3 separator for gas-liquid separation to obtain the final concentrated high brine; the final concentrated high brine is discharged from the bottom of the single-effect 3 separator to the primary freezing kettle for freezing, the frozen high brine is sent to the primary centrifuge for solid-liquid separation, the primary mother liquor after centrifugation is again transported to the single-effect 4 heater for heating, and then transported to the single-effect 4 separator for gas-liquid separation, and then transported to the secondary freezing kettle for freezing, and after freezing, it is transported to the secondary centrifuge for solid-liquid separation, the separated secondary mother liquor is transported to the single-effect 5 heater for heating, and then transported to the single-effect 5 separator for gas-liquid separation, and then sent to the tertiary freezing kettle for freezing, and after freezing, it is sent to the tertiary centrifuge for solid-liquid separation, and the treatment is completed.

[0014] The negative pressure of the first-effect heater described in the above step (2) is 50±10Kpa and the temperature is 85±5°C.

[0015] The negative pressure of the double-effect heater described in the above step (2) is 50±10Kpa and the temperature is 88±5°C.

[0016] The negative pressure of the triple-effect heater described in the above step (2) is 50±10Kpa and the temperature is 90±5°C.

[0017] Among them, the gas (steam) separated by the first-effect separator, the second-effect separator, and the third-effect separator is transported to the compressor through a pipeline. Through compression, the gas is heated up and then transported to the first-effect heater, the second-effect heater, and the third-effect heater, helping these three machines to increase the temperature and save costs.

[0018] The freezing temperature in the above step (3) is 45°C-55°C.

[0019] The rotation speed of the centrifuge described in the above step (3) is 35HZ.

[0020] The heating temperatures of the single-effect heater 1, single-effect heater 2, single-effect heater 3 and single-effect heater 4 in the above step (3) are all 85°C-115°C.

[0021] The negative pressures of the single-effect 1 heater, the single-effect 2 heater, the single-effect 3 heater, and the single-effect 4 heater described in the above step (3) are all 50Kpa-90Kpa.

[0022] MVR continuously feeds to single-effect continuous discharge, separates secondary mother liquor and ammonium chloride salt; primary mother liquor enters single-effect 2 for evaporation and concentration again, and secondary mother liquor enters single-effect 3 for evaporation and concentration again, ensuring the continuity of production.

[0023] The beneficial effects compared with the prior art are:

[0024] The MVR compressor draws back secondary steam, which is compressed by the compressor and then heated by the system heater again, reducing the use of primary steam. The concentrated material enters the single-effect evaporator with strong sealing performance and effectively controlled on-site environment. The single-effect can continuously feed and discharge materials, resulting in the system's production and withdrawal, and the system's processing capacity is greatly increased. The increased processing capacity reduces production costs, thereby saving energy and protecting the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of the deep treatment of sucralose high-salt wastewater according to the present invention. DETAILED DESCRIPTION

[0026] The above features mentioned in the present invention or the features mentioned in the embodiments can be combined in any way. All the features explained in the specification of this case can be used in combination with any method form, and each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equal or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equal or similar features.

[0027] The present invention will be further described below in conjunction with specific examples. These examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0028] Example 1 A method for deep treatment of sucralose high-salt wastewater

[0029] The steps include:

[0030] (1) The wastewater obtained in the production process of sucralose is sent to a flocculation reaction tank through a lifting pump for flocculation, and then transferred to a vertical flow sedimentation tank for sedimentation, the precipitated sludge is discharged to the sludge tank, and the supernatant overflows to the inclined tube sedimentation tank for secondary sedimentation, the sludge after the secondary sedimentation is discharged to the sludge tank, and the supernatant in the inclined tube sedimentation tank overflows to the raw water tank, completing the physical and chemical pretreatment of the high salt water;

[0031] (2) The pretreated high-salt water enters the first-effect heater from the raw water tank for heating, and then goes to the first-effect separator for gas-liquid separation to obtain high-salt water after one concentration. The high-salt water after one concentration enters the second-effect heater for heating, and then is transported to the second-effect separator for gas-liquid separation to obtain high-salt water after two concentrations; the high-salt water after two concentrations enters the third-effect heater for heating, and then goes to the third-effect separator for gas-liquid separation to obtain high-salt water after three concentrations. The negative pressure of the first-effect heater, the second-effect heater, and the third-effect heater are all 45Kpa, the temperature of the first-effect heater is 90°C, the temperature of the second-effect heater is 92°C, and the temperature of the third-effect heater is 95°C;

[0032] (3) The high brine after three concentrations is transported to the single-effect 1 heater for heating, and the single-effect 1 heater is transported to the single-effect 1 separator for gas-liquid separation. The high brine after concentration is transported from the single-effect 1 separator to the single-effect 2 heater for heating, and then transported to the single-effect 2 separator for gas-liquid separation, and then transported to the single-effect 3 heater for heating, and then transported to the single-effect 3 separator for gas-liquid separation. The concentrated high brine is discharged from the bottom of the single-effect 3 separator to a primary freezing kettle for freezing. The freezing temperature is 45° C. The frozen high brine is sent to a primary centrifuge for solid-liquid separation. The centrifuge The speed is 35HZ. After centrifugation, the mother liquor is transported to the single-effect 4 heater for heating again, and then transported to the single-effect 4 separator for gas-liquid separation, and then transported to the secondary freezing kettle for freezing. The freezing temperature is 45°C. After freezing, it is transported to the secondary centrifuge for solid-liquid separation. The centrifuge speed is 35HZ. After separation, the mother liquor is transported to the single-effect 5 heater for heating, and then transported to the single-effect 5 separator for gas-liquid separation, and then transported to the tertiary freezing kettle for freezing. The freezing temperature is 45°C. After freezing, it is transported to the tertiary centrifuge for solid-liquid separation. The centrifuge speed is 35HZ, and the treatment is completed.

[0033] The temperature of each single-effect heater is 115°C and the negative pressure is 50Kpa.

[0034] Example 2 A method for deep treatment of sucralose high-salt wastewater

[0035] The steps include:

[0036] (1) The wastewater obtained in the production process of sucralose is sent to a flocculation reaction tank through a lifting pump for flocculation, and then transferred to a vertical flow sedimentation tank for sedimentation, the precipitated sludge is discharged to the sludge tank, and the supernatant overflows to the inclined tube sedimentation tank for secondary sedimentation, the sludge after the secondary sedimentation is discharged to the sludge tank, and the supernatant in the inclined tube sedimentation tank overflows to the raw water tank, completing the physical and chemical pretreatment of the high salt water;

[0037] (2) The pretreated high-salt water enters the first-effect heater from the raw water tank for heating, and then goes to the first-effect separator for gas-liquid separation to obtain high-salt water after one concentration. The high-salt water after one concentration enters the second-effect heater for heating, and then is transported to the second-effect separator for gas-liquid separation to obtain high-salt water after two concentrations; the high-salt water after two concentrations enters the third-effect heater for heating, and then goes to the third-effect separator for gas-liquid separation to obtain high-salt water after three concentrations. The negative pressure of the first-effect heater, the second-effect heater, and the third-effect heater are all 50Kpa, the temperature of the first-effect heater is 87°C, the temperature of the second-effect heater is 90°C, and the temperature of the third-effect heater is 94°C;

[0038] (4) The high brine after three concentrations is transported to the single-effect 1 heater for heating, and the single-effect 1 heater is transported to the single-effect 1 separator for gas-liquid separation. The high brine after concentration is transported from the single-effect 1 separator to the single-effect 2 heater for heating, and then transported to the single-effect 2 separator for gas-liquid separation, and then transported to the single-effect 3 heater for heating, and then transported to the single-effect 3 separator for gas-liquid separation. The concentrated high brine is discharged from the bottom of the single-effect 3 separator to a primary freezing kettle for freezing. The freezing temperature is 55° C. The frozen high brine is sent to a primary centrifuge for solid-liquid separation. The centrifuge The speed is 35HZ. After centrifugation, the mother liquor is transported to the single-effect 4 heater for heating again, and then transported to the single-effect 4 separator for gas-liquid separation, and then transported to the secondary freezing kettle for freezing. The freezing temperature is 55°C. After freezing, it is transported to the secondary centrifuge for solid-liquid separation. The centrifuge speed is 35HZ. After separation, the mother liquor is transported to the single-effect 5 heater for heating, and then transported to the single-effect 5 separator for gas-liquid separation, and then transported to the tertiary freezing kettle for freezing. The freezing temperature is 55°C. After freezing, it is transported to the tertiary centrifuge for solid-liquid separation. The centrifuge speed is 35HZ, and the treatment is completed.

[0039] The temperature of each single-effect heater is 100°C and the negative pressure is 60Kpa.

[0040] Example 3 A method for deep treatment of sucralose high-salt wastewater

[0041] The steps include:

[0042] (1) The wastewater obtained in the production process of sucralose is sent to a flocculation reaction tank through a lifting pump for flocculation, and then transferred to a vertical flow sedimentation tank for sedimentation, the precipitated sludge is discharged to the sludge tank, and the supernatant overflows to the inclined tube sedimentation tank for secondary sedimentation, the sludge after the secondary sedimentation is discharged to the sludge tank, and the supernatant in the inclined tube sedimentation tank overflows to the raw water tank, completing the physical and chemical pretreatment of the high salt water;

[0043] (2) The pre-treated high-salt water enters the first-effect heater from the raw water tank for heating, and then goes to the first-effect separator for gas-liquid separation to obtain high-salt water after one concentration. The high-salt water after one concentration enters the second-effect heater for heating, and then is transported to the second-effect separator for gas-liquid separation to obtain high-salt water after two concentrations; the high-salt water after two concentrations enters the third-effect heater for heating, and then goes to the third-effect separator for gas-liquid separation to obtain high-salt water after three concentrations. The negative pressure of the first-effect heater, the second-effect heater, and the third-effect heater are all 60Kpa, the temperature of the first-effect heater is 70℃, the temperature of the second-effect heater is 73℃, and the temperature of the third-effect heater is 75℃;

[0044] (5) The high brine after three concentrations is transported to the single-effect 1 heater for heating, and the single-effect 1 heater is transported to the single-effect 1 separator for gas-liquid separation. The high brine after concentration is transported from the single-effect 1 separator to the single-effect 2 heater for heating, and then transported to the single-effect 2 separator for gas-liquid separation, and then transported to the single-effect 3 heater for heating, and then transported to the single-effect 3 separator for gas-liquid separation. The concentrated high brine is discharged from the bottom of the single-effect 3 separator to a primary freezing kettle for freezing. The freezing temperature is 50° C. The frozen high brine is sent to a primary centrifuge for solid-liquid separation. The centrifuge The speed is 35HZ. After centrifugation, the mother liquor is transported to the single-effect 4 heater for heating again, and then transported to the single-effect 4 separator for gas-liquid separation, and then transported to the secondary freezing kettle for freezing. The freezing temperature is 50℃. After freezing, it is transported to the secondary centrifuge for solid-liquid separation. The centrifuge speed is 35HZ. After separation, the mother liquor is transported to the single-effect 5 heater for heating, and then transported to the single-effect 5 separator for gas-liquid separation, and then transported to the tertiary freezing kettle for freezing. The freezing temperature is 50℃. After freezing, it is transported to the tertiary centrifuge for solid-liquid separation. The centrifuge speed is 35HZ, and the treatment is completed.

[0045] The temperature of each single-effect heater is 85°C and the negative pressure is 70Kpa.

[0046] Comparative Example 1

[0047] The method disclosed in patent CN110803821A.

[0048] Comparative Example 2

[0049] The method disclosed in patent CN110723854A.

[0050] Effect detection:

[0051] Detection method: Use COD detection instrument to detect the COD content in the treated wastewater;

[0052] The ammonia nitrogen content in wastewater was detected by neutralization titration.

[0053] The test results are shown in Table 1 below.

[0054] Table 1

[0055] Average COD content (mg / L) Average ammonia nitrogen content (mg / L) Example 1 71000 30000 Example 2 85000 36000 Example 3 77000 32200 Comparative Example 1 96000 40000 Comparative Example 2 110000 46000

[0056] According to the test results in Table 1 above, it can be seen that when the method provided by the present invention is used to treat wastewater, the COD content and ammonia nitrogen content in the water are significantly reduced after the treatment, and the wastewater has a better treatment effect.

[0057] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for deep treatment of sucralose high-salt wastewater, characterized in that: The steps include: (1) The wastewater obtained in the production process of sucralose is sent to a flocculation reaction tank through a lifting pump for flocculation, and then transferred to a vertical flow sedimentation tank for sedimentation, the precipitated sludge is discharged to the sludge tank, and the supernatant overflows to the inclined tube sedimentation tank for secondary sedimentation, the sludge after the secondary sedimentation is discharged to the sludge tank, and the supernatant in the inclined tube sedimentation tank overflows to the raw water tank, completing the physical and chemical pretreatment of the high salt water; (2) The pretreated high-salt water enters the first-effect heater from the raw water tank for heating, and then enters the first-effect separator for gas-liquid separation to obtain high-salt water after primary concentration; the high-salt water after primary concentration enters the second-effect heater for heating, and then is transported to the second-effect separator for gas-liquid separation to obtain high-salt water after secondary concentration; the high-salt water after secondary concentration enters the third-effect heater for heating, and then enters the third-effect separator for gas-liquid separation to obtain high-salt water after tertiary concentration; (3) The high brine after tertiary concentration is transported to the single-effect 1 heater for heating, and then transported to the single-effect 1 separator for gas-liquid separation to obtain concentrated high brine; the concentrated high brine is transported from the single-effect 1 separator to the single-effect 2 heater for heating, and then transported to the single-effect 2 separator for gas-liquid separation to obtain high brine after re-concentration; the high brine after re-concentration is transported to the single-effect 3 heater for heating, and then transported to the single-effect 3 separator for gas-liquid separation to obtain the final concentrated high brine; the final concentrated high brine is discharged from the bottom of the single-effect 3 separator to the primary freezing kettle for freezing, the frozen high brine is sent to the primary centrifuge for solid-liquid separation, the primary mother liquor after centrifugation is again transported to the single-effect 4 heater for heating, and then transported to the single-effect 4 separator for gas-liquid separation, and then transported to the secondary freezing kettle for freezing, and after freezing, it is transported to the secondary centrifuge for solid-liquid separation, the separated secondary mother liquor is transported to the single-effect 5 heater for heating, and then transported to the single-effect 5 separator for gas-liquid separation, and then sent to the tertiary freezing kettle for freezing, and after freezing, it is sent to the tertiary centrifuge for solid-liquid separation, and the treatment is completed.

2. The method according to claim 1, characterized in that: The negative pressure of the first-effect heater described in step (2) is 50±10Kpa and the temperature is 85±5°C.

3. The method according to claim 1, characterized in that: The negative pressure of the double-effect heater described in step (2) is 50±10Kpa and the temperature is 88±5°C.

4. The method according to claim 1, characterized in that: The negative pressure of the triple-effect heater described in step (2) is 50±10Kpa and the temperature is 90±5°C.

5. The method according to claim 1, characterized in that: The freezing temperature described in step (3) is 45°C-55°C.

6. The method according to claim 1, characterized in that: The rotation speed of the centrifuge described in step (3) is 35HZ.

7. The method according to claim 1, characterized in that: The heating temperatures of the single-effect 1 heater, the single-effect 2 heater, the single-effect 3 heater, and the single-effect 4 heater described in step (3) are all 85° C.-115° C.

8. The method according to claim 7, characterized in that: The heating temperatures of the single-effect 1 heater, the single-effect 2 heater, the single-effect 3 heater, and the single-effect 4 heater described in step (3) are all 100°C.

9. The method according to claim 1, characterized in that: The negative pressures of the single-effect 1 heater, the single-effect 2 heater, the single-effect 3 heater, and the single-effect 4 heater described in step (3) are all 50Kpa-90Kpa.

10. The method according to claim 1, characterized in that: The negative pressure of the single-effect 1 heater, the single-effect 2 heater, the single-effect 3 heater, and the single-effect 4 heater described in step (3) is 20Kpa.

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