A system for co-processing sodium sulfate waste salt residue and domestic waste incineration fly ash washing wastewater

Abstract

The utility model discloses a kind of sodium sulfate waste salt slag and domestic waste incineration fly ash washing wastewater synergic treatment system, including sodium sulfate waste salt slag processing system and domestic waste incineration fly ash washing system, sodium sulfate waste salt slag processing system includes and is connected in order front processing system, slurry device and filter-pressing device according to processing process;Domestic waste incineration fly ash washing system includes and is connected in order heavy metal removal device, calcium removal device, filter device and evaporation salt separation crystallization device according to processing process;Filter-pressing device is connected with calcium removal device, evaporation salt separation crystallization device is connected with slurry device, and evaporation distillate water produced by evaporation salt separation crystallization device is used for water supply for slurry device.Using the processing system of the application, the effective and reasonable treatment of sodium sulfate waste salt slag and domestic waste incineration wastewater washing wastewater is realized, sodium sulfate salt solution can be directly used for calcium removal of washing wastewater, greatly reduce the amount of sodium carbonate, energy saving and consumption reduction.

Description

Technical Field

[0001] This utility model belongs to the field of solid waste treatment technology for environmental protection, specifically relating to a co-treatment system for sodium sulfate waste salt residue and wastewater from fly ash washing of municipal solid waste incineration. Background Technology

[0002] The production of many chemical products (especially pesticides, pharmaceuticals, fine chemicals, organic chemicals, dyes, etc.) generates a large amount of waste salt residue. The amount of industrial waste salt residue generated by my country's industrial production is about 1.2 million tons per year. In addition to the waste salt residue that was previously untreated and stockpiled, as well as the waste salt residue generated by the evaporation of high-salt wastewater from other industries, the total amount of industrial waste salt residue in the country is estimated to be more than 10 million tons. Among the vast quantities of industrial waste salt residue, sodium sulfate waste salt residue accounts for a significant proportion. Its main component is sodium sulfate, along with approximately 10% organic matter and small amounts of impurities such as calcium, magnesium, and iron ions. Because waste salt residue often contains various organic compounds, it exhibits different colors and emits various unpleasant odors, posing a significant threat to the environment and human health. Currently, some waste salt residue is collected and solidified by qualified landfill disposal units for a fee, but the processing capacity is very limited and it occupies a large amount of land resources. Other waste salt residue is recovered through heat treatment and recrystallization, but this involves large equipment investments, high energy consumption, and low economic benefits. The remaining waste salt residue is temporarily stored in newly built warehouses by various enterprises, severely restricting the production, operation, and sustainable development of these agrochemical companies.

[0003] With rapid economic development and improved living standards, the amount of municipal solid waste generated is increasing, and the amount of fly ash produced by its incineration is also growing. Statistics show that my country currently generates over ten million tons of fly ash annually from municipal solid waste incineration. As hazardous waste, fly ash is primarily disposed of through landfill, which not only occupies significant land resources but also poses a serious risk of secondary pollution. The resource utilization of fly ash is urgently needed. Water washing is an essential step in this process, but it generates large amounts of wastewater with extremely high calcium content. Currently, calcium removal is mainly achieved using industrial sodium carbonate solids prepared into a solution, which is very costly. Utility Model Content

[0004] One technical problem this application aims to solve is to overcome the deficiencies of the above-mentioned related technologies and provide a co-treatment system for sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater. The sodium sulfate solution obtained after treating the sodium sulfate waste salt residue can be directly used to remove calcium from the washing wastewater, which greatly reduces the amount of sodium carbonate used, realizes resource regeneration, and saves costs.

[0005] The technical solution adopted by this utility model to solve the technical problem is as follows: A co-treatment system for sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater includes a sodium sulfate waste salt residue treatment system and a municipal solid waste incineration fly ash washing system. The sodium sulfate waste salt residue treatment system includes a pretreatment system, a slurrying device, and a filter press connected in sequence according to the treatment process. The municipal solid waste incineration fly ash washing system includes a heavy metal removal device, a calcium removal device, a filtration device, and an evaporation and salt separation crystallization device connected in sequence according to the treatment process. The filter press is connected to the calcium removal device, and the evaporation and salt separation crystallization device is connected to the slurrying device. The distillate produced by the evaporation and salt separation crystallization device is used to supply water to the slurrying device.

[0006] Furthermore, the evaporation and salt separation crystallization device is connected to the slurrying device through an evaporation distillation water tank, which can be used to store the evaporation distillation water produced by the evaporation and salt separation crystallization device.

[0007] Furthermore, the filter press is connected to the evaporation distillation tank, and the distillate from the evaporation distillation tank is used to wash the filter press. The filter press is connected to the washing liquid tank, which is connected to the slurry processing device. By washing the filter cake, the sodium sulfate in the filter cake is carried out to the washing liquid and then returned to the slurry processing device, thereby improving the recovery rate of sodium sulfate.

[0008] Furthermore, the calcium removal device includes a primary calcium removal device, a third filter press, a secondary calcium removal device, and a fourth filter press. The primary calcium removal device is connected to the third filter press, the third filter press is connected to the secondary calcium removal device, the secondary calcium removal device is connected to the fourth filter press, the fourth filter press is connected to the filtration device, and the primary calcium removal device is connected to the heavy metal removal device. The calcium sulfate sludge discharged after filtration by the third and fourth filter presses enters the backwashing system.

[0009] Furthermore, the third filter press is connected to the secondary calcium removal device through the third filtrate tank, and the fourth filter press is connected to the filtration device through the fourth filtrate tank. The fourth filtrate tank is used to store the fluid filtered by the third filter press and the fourth filtrate tank is used to store the fluid filtered by the fourth filter press.

[0010] Furthermore, the pretreatment system includes a combustion heating device, a low-temperature anaerobic pyrolysis furnace, and a flue gas treatment device. The combustion heating device is connected to the low-temperature anaerobic pyrolysis furnace, the low-temperature anaerobic pyrolysis furnace is connected to the flue gas treatment device, and the flue gas treatment device is connected to a pulping device. The low-temperature anaerobic pyrolysis furnace performs anaerobic decomposition of municipal solid waste to obtain pyrolysis gas. The pyrolysis gas is mixed with natural gas and can be used to heat the combustion heating device. The combustion heating system and the low-temperature anaerobic pyrolysis furnace are equipped with a flue gas treatment system for discharging the high-temperature oil and gas generated by the low-temperature anaerobic pyrolysis furnace.

[0011] Furthermore, the heavy metal removal device includes a storage tank, a heavy metal removal reaction tank, a second filter press, and a second filtrate tank. The storage tank is connected to the heavy metal removal reaction tank, the heavy metal removal reaction tank is connected to the second filter press, the second filter press is connected to the second filtrate tank, and the second filtrate tank is connected to the calcium removal device. The storage tank is used to store the wastewater from the fly ash washing process of municipal solid waste incineration.

[0012] Furthermore, the filtration device includes a sand filter and a fine filter, the sand filter is connected to the fine filter, the sand filter is connected to the calcium removal device, and the fine filter is connected to the pH adjustment device.

[0013] Furthermore, the municipal solid waste incineration fly ash washing system also includes a refined mixed salt solution tank, the pH adjustment device is connected to the refined mixed salt solution tank, the pH adjustment device is connected to the filtration device, and the refined mixed salt solution tank is connected to the evaporation and salt separation device.

[0014] Furthermore, the filter press device includes a first filter press and a first filtrate tank, the first filter press being connected to the first filtrate tank, the first filter press being connected to the slurry device, and the first filtrate tank being connected to the calcium removal device.

[0015] Compared with related technologies, this utility model has the following advantages: 1. The sodium sulfate waste salt residue treatment system and the municipal solid waste incineration fly ash washing system can effectively and rationally treat sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater in synergy, solving the problem of sodium sulfate waste salt residue treatment and having good environmental benefits; 2. The sodium sulfate solution obtained after the sodium sulfate waste salt residue is treated by the sodium sulfate waste salt residue treatment system can be directly used in the calcium removal process of the water washing wastewater in the municipal solid waste incineration fly ash washing system, which greatly reduces the amount of sodium carbonate used, realizes resource recycling, and saves costs. 3. Compared with traditional waste salt residue treatment processes, it greatly simplifies the treatment process and reduces investment and operating costs.

[0016] 4. Sodium chloride and potassium chloride salts that meet relevant product standards and are refined from fly ash washing salt solution are sold as products, realizing resource recycling and generating considerable economic benefits.

[0017] 5. The evaporation distillate generated by the fly ash washing system of municipal solid waste incineration is recycled in the sodium sulfate waste salt residue treatment system for slurrying and pressure filtration processes, realizing complete and comprehensive recycling of wastewater with no wastewater discharge. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a process flow diagram of this utility model; In the diagram: 1-Pulping unit; 2-Evaporation and salt separation crystallization unit; 3-Combustion heating unit; 4-Low-temperature oxygen-free pyrolysis furnace; 5-Flue gas treatment unit; 6-Storage tank; 7-Heavy metal removal reaction tank; 8-Second filter press; 9-Second filtrate tank; 10-First-stage calcium removal unit; 11-Third filter press; 12-Third filtrate tank; 13-Second-stage calcium removal unit; 14-Fourth filter press; 15-Fourth filtrate tank; 16-Sand filter; 17-Fine filter Apparatus; 18-pH adjustment device; 19-refined mixed salt solution tank; 20-first filter press; 21-first filtrate tank; 22-washing liquid tank; 23-evaporated distillate tank; 26-second lift pump; 27-third lift pump; 28-second filter press pump; 29-fourth lift pump; 30-third filter press pump; 31-fifth lift pump; 32-fourth filter press pump; 33-sixth lift pump; 34-seventh lift pump; 38-eighth lift pump. Detailed Implementation

[0019] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Example

[0021] A co-treatment system for sodium sulfate waste salt residue and wastewater from municipal solid waste incineration fly ash washing, such as... Figures 1-2 As shown, the system includes a sodium sulfate waste salt residue treatment system and a municipal solid waste incineration fly ash washing system. The sodium sulfate waste salt residue treatment system comprises a pretreatment system, a slurry preparation unit 1, and a filter press connected sequentially according to the treatment process. The municipal solid waste incineration fly ash washing system comprises a heavy metal removal unit, a calcium removal unit, a filtration unit, and an evaporation and salt separation crystallization unit 2 connected sequentially according to the treatment process. The calcium removal unit is connected to the filter press, and the evaporation and salt separation crystallization unit 2 is connected to the slurry preparation unit 1. The distillate from the evaporation and salt separation crystallization unit 2 is used to supply water to the slurry preparation unit 1, and the sodium sulfate solution produced by the filter press is used in the calcium removal unit to remove calcium from the municipal solid waste incineration fly ash.

[0022] The evaporation and salt separation crystallization device 2 is connected to the slurrying device 1 through the evaporation distillation water tank 23. The evaporation distillation water tank 23 can be used to store the evaporation distillation water generated by the evaporation and salt separation crystallization device 2. The evaporation distillation water is recycled and used for slurrying treatment in the sodium sulfate waste salt residue treatment system.

[0023] The sodium sulfate solution produced by the filter press is stored in the first filtrate tank 21. The first filtrate tank 21 sends the sodium sulfate solution to the calcium removal device through the second lift pump 26. The evaporated distillate produced by the evaporation and salt separation crystallization device 2 is stored in the evaporated distillate tank 23. The evaporated distillate tank 23 sends the evaporated distillate to the slurry device 1 and the filter press respectively through the eighth lift pump 38.

[0024] The pretreatment system includes a combustion heating device 3, a low-temperature anaerobic pyrolysis furnace 4, and a flue gas treatment device 5. The low-temperature anaerobic pyrolysis furnace 4 decomposes sodium sulfate waste salt residue into sodium sulfate salt residue and pyrolysis gas. The pyrolysis gas is recovered and mixed with natural gas to provide combustion heating for the combustion heating device 3. The high-temperature flue gas produced is discharged after passing through the flue gas treatment device 5 to meet the standards.

[0025] The heavy metal removal device includes a storage tank 6, a heavy metal removal reaction tank 7, a second filter press 8, and a second filtrate tank 9. The storage tank 6 stores wastewater from municipal solid waste incineration. The wastewater is pumped from the storage tank 6 to the heavy metal removal reaction tank 7 via a third lift pump 27. Hydrochloric acid, sodium sulfide solution, and PAM are added to the reaction tank 7 to react with the heavy metals. The fluid is then pumped to the second filter press 8 via a second filter press pump 28. The second filter press 8 discharges the heavy metal-containing sludge and sends the remaining fluid to the second filtrate tank 9. The second filtrate tank 9 then pumps the temporarily stored fluid to the calcium removal device via a fourth lift pump 29 to react with sodium sulfate solution.

[0026] The calcium removal system includes a primary calcium removal unit 10, a third filter press 11, a secondary calcium removal unit 13, and a fourth filter press 14. The fluid after reaction in the primary calcium removal unit 10 is sent to the third filter press 11 via the third filter press pump 30. The filtrate produced by the filter press flows by gravity to the third filtrate tank 12. The third filtrate tank 12 sends the filtrate to the secondary calcium removal reactor 13 via the fifth lift pump 31. Sodium carbonate solution is added to the secondary calcium removal reactor 13 for reaction. The fluid after reaction is sent to the fourth filter press 14 via the fourth filter press pump 32. The filtrate produced by the fourth filter press 14 flows by gravity to the fourth filtrate tank 15. The calcium carbonate sludge discharged from the third filter press 11 and the fourth filter press 14 enters the return water system.

[0027] The filtration device includes a sand filter 16 and a fine filter 17. The sixth lift pump 33 sends the fluid stored in the fourth filtrate tank 15 to the sand filter 16 and then to the fine filter 17 for further filtration.

[0028] The municipal solid waste incineration fly ash washing system also includes a pH adjustment device 18 and a refined mixed salt solution tank 19. The filtrate filtered by the fine filtration device 17 flows by gravity into the pH adjustment device 18. Dilute hydrochloric acid is added to the pH adjustment device 18, reacting with the filtrate to produce a refined mixed salt solution, which is temporarily stored in the refined mixed salt solution tank 19. A seventh booster pump 34 sends the refined mixed salt solution to the evaporation and crystallization device 2, thereby producing sodium chloride, potassium chloride, and evaporated distillate. The sodium chloride and potassium chloride are sold externally. The evaporation and crystallization device is connected to the slurry processing device via the evaporated distillate tank.

[0029] The filter press device includes a first filter press 20 and a first filtrate tank 21. The first filter press 20 is connected to the first filtrate tank 21 and is connected to the slurry device 1. The first filtrate tank 21 is connected to the calcium removal device.

[0030] The sodium sulfate residue generated by the pretreatment system is stirred and slurried with the evaporated water and then filtered by pressure. The filter cake is then washed multiple times with the evaporated water. The filter cake is carbon black, which can be sold for comprehensive utilization. The washing liquid generated by rinsing flows by gravity to the washing liquid tank 22 for temporary storage and is then returned to the slurry unit for recycling. The filtrate generated by pressure filtration is sodium sulfate solution, which flows by gravity to the first filtrate tank 21 for temporary storage. The first filtrate tank 21 sends the sodium sulfate solution to the primary calcium removal unit 10 through the second lift pump 26 as the raw material for primary calcium removal.

[0031] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A co-treatment system for sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater, comprising a sodium sulfate waste salt residue treatment system and a municipal solid waste incineration fly ash washing system, characterized in that: The sodium sulfate waste salt residue treatment system includes a pretreatment system, a slurry device (1) and a filter press device connected in sequence according to the treatment process; The municipal solid waste incineration fly ash washing system includes a heavy metal removal device, a calcium removal device, a filtration device, and an evaporation and salt separation crystallization device connected in sequence according to the treatment process (2); The filter press is connected to the calcium removal device, the evaporation and salt separation crystallization device (2) is connected to the slurry device (1), and the evaporated distillate produced by the evaporation and salt separation crystallization device (2) is used to supply water to the slurry device (1).

2. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 1, characterized in that: The evaporation salt crystallization device (2) is connected to the slurry device (1) through an evaporation distillation water tank (23), which can be used to store the evaporation distillation water produced by the evaporation salt crystallization device (2).

3. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 2, characterized in that: The evaporation distillation tank (23) is connected to the filter press, the filter press is connected to the washing liquid tank (22), and the washing liquid tank (22) is connected to the slurry device (1).

4. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 1, characterized in that: The calcium removal device includes a primary calcium removal device (10), a third filter press (11), a secondary calcium removal device (13), and a fourth filter press (14). The primary calcium removal device (10) is connected to the third filter press (11), the third filter press (11) is connected to the secondary calcium removal device (13), the secondary calcium removal device (13) is connected to the fourth filter press (14), the fourth filter press (14) is connected to the filtration device, and the primary calcium removal device (10) is connected to the heavy metal removal device.

5. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 4, characterized in that: The third filter press (11) is connected to the secondary calcium removal device (13) through the third filtrate tank (12), and the fourth filter press (14) is connected to the filtration device through the fourth filtrate tank (15).

6. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 1, characterized in that: The pretreatment system includes a combustion heating device (3), a low-temperature anaerobic pyrolysis furnace (4), and a flue gas treatment device (5). The combustion heating device (3) is connected to the low-temperature anaerobic pyrolysis furnace (4), the low-temperature anaerobic pyrolysis furnace (4) is connected to the flue gas treatment device (5), and the flue gas treatment device (5) is connected to the pulping device (1).

7. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 1, characterized in that: The heavy metal removal device includes a storage tank (6), a heavy metal removal reaction tank (7), a second filter press (8), and a second filtrate tank (9). The storage tank (6) is connected to the heavy metal removal reaction tank (7), the heavy metal removal reaction tank (7) is connected to the second filter press (8), the second filter press (8) is connected to the second filtrate tank (9), and the second filtrate tank (9) is connected to the calcium removal device. The storage tank (6) is used to store the wastewater from the fly ash washing process of municipal solid waste incineration.

8. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 1, characterized in that: The filtration device includes a sand filter (16) and a fine filter (17). The sand filter (16) is connected to the fine filter (17), the sand filter (16) is connected to the calcium removal device, and the fine filter is connected to the pH adjustment device (18).

9. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 8, characterized in that: The municipal solid waste incineration fly ash washing system also includes a refined mixed salt solution tank (19), the pH adjustment device (18) is connected to the refined mixed salt solution tank (19), the pH adjustment device (18) is connected to the filter device, and the refined mixed salt solution tank (19) is connected to the evaporation and salt separation crystallization device (2).

10. The system for co-treating sodium sulfate waste salt residue and municipal solid waste incineration fly ash washing wastewater according to claim 1, characterized in that: The filter press device includes a first filter press (20) and a first filtrate tank (21). The first filter press (20) is connected to the first filtrate tank (21). The first filter press (20) is connected to the slurry device (1). The first filtrate tank (21) is connected to the calcium removal device.

Images