Desulfurized fly ash recycling system

Abstract

The utility model discloses a desulfurization ash recycling system. The device comprises an oxidation tank, a primary dissolution tank, a dissolution tank, a first reaction tank, a first clarification tank, a filter, a softening reaction tank, a microfiltration membrane, a nanofiltration, an ammonia absorption tower, a first carbonization tower, a second carbonization tower, a second thickener, a first thickener, an alkali filter, a mother liquor tank, a dryer, a nanofiltration concentrated water crystallizer, a first slurry tank, a plate-and-frame filter press, a third slurry tank, a salt slurry tank, a flow divider and a neutralization tower. A third reaction tank, a third clarification tank, a fourth reaction tank, a fourth clarification tank, a fourth slurry tank, an electrolytic oxidation unit and a centrifugal dehydrator; according to the utility model, the operation energy consumption is effectively reduced, and the investment is reduced, so that the device has stronger economical efficiency; meanwhile, sodium bicarbonate generated by the system is high in cleanliness and activity, and the flue gas desulfurization reaction efficiency is high.

Description

Technical Field

[0001] The utility model relates to the technical field of robots, in particular to a desulfurized ash resource utilization system. Background Art

[0002] The SDS dry desulfurization technology uses sodium bicarbonate dry powder to fully contact with acidic flue gas in the flue, and physical and chemical reactions occur, and acidic substances such as SO2 in the flue gas are absorbed and purified.

[0003] Its main chemical reaction is:

[0004] 2NaHCO 3 +SO 2 +1 / 2O 2 →Na 2 SO 4 +2CO 2 +H 2 O

[0005] 2NaHCO 3 +SO 3 →Na 2 SO 4 +2CO 2 +H 2 O

[0006] Reaction with other acidic substances (such as SO 3 etc.):

[0007] NaHCO 3 +HCl→NaCl+CO 2 +H 2 O

[0008] NaHCO 3 +HF→NaF+CO 2 +H 2 O

[0009] The SDS desulfurization process has good and suitable adjustment characteristics, and has technical advantages such as simple system, convenient maintenance, small floor area, low operation cost, and no need for water in the desulfurization and deacidification process. Therefore, it has been widely used in the dry deacidification industry in China and can achieve ultra-low emissions of flue gas.

[0010] The main waste generated by the SDS desulfurization and deacidification process is desulfurized fly ash, and its components are mainly sodium sulfate, sodium sulfite, sodium chloride, sodium fluoride, and unreacted sodium bicarbonate, sodium carbonate, dust, etc.

[0011] Since more than 97% of the components of desulfurized fly ash are salts that are soluble in water, according to the existing environmental protection regulations in China, rigid landfill disposal is required, which in turn leads to the high disposal cost of this part of desulfurized ash.

[0012] To solve the problem of the disposal of this part of fly ash, one method is to dissolve, purify, evaporate and crystallize, and purify it to produce sodium sulfate, and sell the sodium sulfate as an industrial by-product salt. However, considering that it may contain heavy metals and other substances and the removal is not complete, there is a risk of generating hazardous waste. At the same time, the disposal method of producing sodium sulfate is not economical.

[0013] In China, there are technical means such as dissolving fly ash, purifying it, reacting with ammonium bicarbonate or ammonia, and CO2 to produce sodium bicarbonate and by-product ammonium sulfate. This technical direction has found a new direction for the resource recovery and recycling of desulfurized ash, and domestic manufacturers have also successively tried it. However, in actual operation, there are the following several problems that are difficult to solve:

[0014] 1. Since the components of desulfurized ash are complex, it is necessary to first dissolve and purify it. The purified salt solution enters the metathesis reaction unit to produce sodium bicarbonate and ammonium sulfate. However, the existing methods have high investment costs, large steam consumption in the system, high energy consumption. At the same time, when using the direct metathesis reaction method of sodium sulfate and ammonium bicarbonate, or the reaction of sodium sulfate with ammonia and CO2 in a carbonation tower to produce sodium bicarbonate and ammonium sulfate, the produced sodium bicarbonate has more impurities, poor activity, and low reaction efficiency. After comprehensive evaluation, the actual operation economy fails to meet the expectations, and its sodium bicarbonate activity is quite different from that produced by the domestic ammonia-soda process.

[0015] The main factor is that after the desulfurized ash is dissolved, it is difficult to purify it completely, resulting in the accumulation of harmful substances during continuous operation. As it enters the sodium bicarbonate, it causes large product adhesion, reduces activity, results in unstable flue gas desulfurization effect, and low reaction efficiency.

[0016] 2. Since the components of desulfurized ash contain a relatively high amount of chloride ions, the produced ammonium sulfate has low purity and poor quality, failing to meet the expected indicators. At the same time, it can only be sold at a low price as a general product, and thus fails to reach the expected economic indicators. At the same time, the ammonium sulfate market in China is mainly dominated by by-product ammonium sulfate. When using ammonium bicarbonate or ammonia water and CO2 to produce sodium bicarbonate and co-produce ammonium sulfate, it results in an actual cost inversion and a loss state.

[0017] 3. In the existing system, in addition to the unstable operation, the product quality continuously decreases with the operation cycle. The main problem is still the incomplete purification of impurities. With the accumulation of cycles, the reasonable reaction interval of the system is damaged, and the phase diagram structure of the components of each salt changes, resulting in low reaction efficiency or the reaction cannot continue, causing a large amount of mother liquor to be discharged.

[0018] For this reason, we propose a desulfurized ash resource utilization system. Summary of the Utility Model

[0019] The purpose of the present utility model is to provide a desulfurized ash resource utilization system, thereby solving or at least alleviating one or more of the above problems and other problems existing in the prior art.

[0020] To achieve the above purpose, the main technical solutions adopted by the present utility model include:

[0021] A desulfurized ash resource utilization system, comprising:

[0022] An oxidation tank, an inlet for desulfurized ash to enter is provided on the oxidation tank, an outlet of liquid brine inside the oxidation tank is communicated with an inlet of an electrolytic oxidation unit, and an outlet of the electrolytic oxidation unit is communicated with the inlet on the oxidation tank;

[0023] A centrifuge, an inlet of the centrifuge is communicated with an outlet of salt slurry at the bottom of the oxidation tank, a solid outlet of the centrifuge is communicated with an inlet of a primary dissolution tank, and a liquid outlet of the centrifuge is communicated with the inlet on the oxidation tank;

[0024] A dissolution tank, an inlet of the dissolution tank is communicated with an outlet of the primary dissolution tank, an outlet of the dissolution tank is communicated with an inlet of a first reaction tank, an outlet of the first reaction tank is communicated with an inlet of a first clarifying tank, a clear liquid outlet of the first clarifying tank is communicated with an inlet of a filter, and an outlet of the filter is communicated with an inlet of a softening reaction tank;

[0025] A microfiltration membrane, a salt solution outlet of the softening reaction tank is connected to the microfiltration membrane, and a clear liquid outlet of the microfiltration membrane is communicated with an inlet of nanofiltration;

[0026] A salt slurry tank, an outlet of nearly saturated salt solution of the salt slurry tank is communicated with an inlet of an ammonia absorption tower, the produced water of nanofiltration is sodium chloride solution, and a produced water outlet of the nanofiltration is communicated with an inlet of the salt slurry tank;

[0027] A first carbonation tower, an inlet of the first carbonation tower is communicated with an outlet of the salt solution after ammonia absorption of the ammonia absorption tower, a bottom outlet of sodium bicarbonate slurry of the first carbonation tower is communicated with an inlet of a first thickener, a bottom slurry outlet of the first thickener is communicated with an inlet of a filter press, an outlet of the filter press is communicated with an inlet of a dryer, dried sodium bicarbonate is discharged from a drying outlet of the dryer, the filtered slurry of the filter press is communicated with an inlet of a mother liquor tank, and an outlet of the mother liquor tank is communicated with an inlet of the first carbonation tower for returning the mother liquor into the first carbonation tower;

[0028] A second carbonation tower for continuously reacting the mother liquor that has not reacted completely in the first carbonation tower. The inlet of the second carbonation tower is connected to the outlet of the first carbonation tower. The sodium bicarbonate slurry outlet at the bottom of the second carbonation tower is connected to the inlet of the second thickener. The slurry outlet at the bottom of the second thickener is connected to the inlet of the first carbonation tower. The clear liquid outlet at the upper end of the second thickener is connected to the inlet of the second carbonation tower.

[0029] In a desulfurized ash resource utilization system according to the present invention, further comprising a neutralization tower. The inlet of the neutralization tower is connected to the mother liquor outlet of the second carbonation tower. The inlets of ammonia, water, and steam in the neutralization tower are connected to the outlet of a diverter. The mother liquor outlet of the neutralization tower is connected to the inlet of a third reaction tank. The slurry outlet of the third reaction tank is connected to the inlet of a third clarifying tank. The clear liquid outlet of the third clarifying tank is connected to the inlet of a fourth reaction tank. The gaseous ammonia and steam outlets on the fourth reaction tank are connected to the inlet of the diverter. The slurry outlet of the fourth reaction tank is connected to the inlet of a fourth clarifying tank. The outlet containing calcium chloride solution on the fourth clarifying tank is connected to the inlet of the third reaction tank.

[0030] In a desulfurized ash resource utilization system according to the present invention, the condensate water outlet of the fourth reaction tank is connected to the inlet of a dissolution tank.

[0031] In a desulfurized ash resource utilization system according to the present invention, the nanofiltration concentrate outlet is connected to the inlet of a nanofiltration concentrated water crystallizer. The nanofiltration concentrated water crystallizer is provided with a mother liquor discharge port and a sodium chloride crystal salt outlet.

[0032] In a desulfurized ash resource utilization system according to the present invention, the nanofiltration concentrated water crystallizer is provided with a primary heating steam inlet and a secondary steam discharge port. The secondary steam discharge port is connected to the heating steam inlet of the fourth reaction tank.

[0033] In a desulfurized ash resource utilization system according to the present invention, further comprising a first slurry tank. The slurry outlet at the bottom of the first clarifying tank is connected to the inlet of the first slurry tank. The outlet of the first slurry tank is connected to the inlet of a plate and frame filter press. The filtrate outlet of the plate and frame filter press is connected to the inlet of the first clarifying tank. The top of the filter is provided with an anti - rinsing water inlet. The anti - rinsing slurry outlet at the bottom of the filter is connected to the inlet of the first slurry tank. The slurry outlet at the bottom of the softening reaction tank is connected to the inlet of the first slurry tank.

[0034] In a desulfurized ash resource utilization system according to the present invention, further comprising a third slurry tank. The inlet of the third slurry tank is connected to the slurry outlet at the bottom of the third clarifying tank.

[0035] In a desulfurized ash resource utilization system according to the present utility model, the slurry outlet at the bottom of the first reaction tank is communicated with the inlet of the fourth slurry tank.

[0036] In a desulfurized ash resource utilization system according to the present utility model, a water replenishment inlet is provided on the primary dissolution tank, and the supernatant outlet of the primary dissolution tank is communicated with the inlet of the softening reaction tank.

[0037] In a desulfurized ash resource utilization system according to the present utility model, the concentrated filtration liquid outlet on the microfiltration membrane is communicated with the inlet of the softening reaction tank.

[0038] The present utility model at least has the following beneficial effects:

[0039] The present utility model effectively reduces the operation energy consumption and investment, making it have strong economic efficiency; at the same time, the sodium bicarbonate produced by the system has high cleanliness, high activity, and high flue gas desulfurization reaction efficiency. Description of the Drawings

[0040] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation to the present application. In the drawings:

[0041] Figure 1 It is a structural schematic diagram of the present utility model.

[0042] Explanation of the Reference Numerals in the Drawings:

[0043] 1. Oxidation tank; 2. Primary dissolution tank; 3. Dissolution tank; 4. First reaction tank; 5. First clarification tank; 6. Filter; 7. Softening reaction tank; 8. Microfiltration membrane; 9. Nanofiltration; 10. Ammonia absorption tower; 11. First phosphating tower; 12. Second phosphating tower; 13. Second thickener; 14. First thickener; 15. Filter press; 16. Mother liquor tank; 17. Dryer; 18. Nanofiltration concentrated water crystallizer; 19. First slurry tank; 20. Plate and frame filter press; 21. Third slurry tank; 22. Salt slurry tank; 23. Shunt; 24. Neutralization tower; 25. Third reaction tank; 26. Third clarification tank; 27. Fourth reaction tank; 28. Fourth clarification tank; 29. Fourth slurry tank; 30. Electrochemical oxidation unit; 31. Centrifugal dewatering machine. Detailed Embodiments

[0044] The following will describe in detail the embodiments of the present application in conjunction with the drawings and embodiments, so as to fully understand how the present application uses technical means to solve technical problems and achieve the realization process of technical effects and implement accordingly.

[0045] Please refer to Figure 1As shown in the figure, in the embodiment of the present utility model,

[0046] A desulfurized ash resource utilization system is composed of an oxidation tank 1, a primary dissolution tank 2, a dissolution tank 3, a first reaction tank 4, a first clarification tank 5, a filter 6, a softening reaction tank 7, a microfiltration membrane 8, nanofiltration 9, an ammonia absorption tower 10, a first carbonation tower 11, a second carbonation tower 12, a second thickener 13, a first thickener 14, a filter press 15, a mother liquor tank 16, a dryer 17, a nanofiltration concentrated water crystallizer 18, a first slurry tank 19, a plate and frame filter press 20, a third slurry tank 21, a salt slurry tank 22, a diverter 23, a neutralization tower 24, a third reaction tank 25, a third clarification tank 26, a fourth reaction tank 27, a fourth clarification tank 28, a fourth slurry tank 29, an electrolytic oxidation unit 30 and a centrifugal dehydrator 31.

[0047] The desulfurized ash enters from the inlet of the oxidation tank 1. The desulfurized ash in the oxidation tank 1 is in a partially dissolved state. The liquid brine outlet inside it is connected to the inlet of the electrolytic oxidation unit 30, and the salt solution to be oxidized is introduced. After oxidation in the electrolytic oxidation unit 30, the oxidized salt solution enters from the inlet of the oxidation tank 1 for cyclic oxidation. Thus, the organic matter in the desulfurized ash is continuously oxidized in a cycle. The salt slurry outlet at the bottom of the oxidation tank 1 is connected to the inlet of the centrifugal dehydrator 31, and the salt slurry is introduced. After centrifugal dehydration, the salt solution returns to the oxidation tank 1, and the solid outlet of the centrifugal dehydrator 31 is connected to the inlet of the primary dissolution tank 2, and the dehydrated desulfurized ash enters the primary dissolution tank 2. The primary dissolution tank 2 is a stirring tank. The primary dissolution tank 2 has a water replenishment inlet, and the supernatant outlet of the primary dissolution tank 2 is connected to the inlet of the softening reaction tank 7 for introducing part of the supernatant;

[0048] The salt slurry outlet of the primary dissolution tank 2 is connected to the inlet of the dissolution tank 3, and the salt slurry is introduced;

[0049] The top inlet of the primary dissolution tank 2 is connected to the condensate outlet of the fourth reaction tank 27 for introducing the condensate of the steam;

[0050] The outlet of the dissolution tank 3 is connected to the inlet of the first reaction tank 4; the top inlet of the first reaction tank 4 is connected to the salt solution outlet of the fourth clarification tank 28 for introducing the solution containing calcium chloride;

[0051] The following reaction occurs in the first reaction tank 4:

[0052] Na 2 SO 4 +CaCl 2 =CaSO 4 ↓(slightly soluble)+2NaCl

[0053] The slurry after the reaction exits from the outlet of the oxidation tank 1 and enters the first clarifying tank 5. After sedimentation and clarification in the first clarifying tank 5, calcium sulfate mud is formed at the bottom. The calcium sulfate mud is connected to the inlet of the first mud tank 19 through the bottom outlet of the first clarifying tank 5, and the mud is introduced.

[0054] The outlet of the first mud tank 19 is connected to the inlet of the plate and frame filter press 20. After dehydration by plate and frame filtration, the gypsum is discharged. The clear liquid outlet of the plate and frame filter press 20 is connected to the inlet of the first clarifying tank 5, and the filtered clear liquid returns to the first clarifying tank 5.

[0055] There is a coagulant adding port at the top of the first clarifying tank 5.

[0056] The clear liquid outlet of the first clarifying tank 5 is connected to the solution inlet of the filter 6. There is a backwash water inlet at the top of the filter 6. The backwash slurry outlet at the bottom of the filter 6 is connected to the inlet of the first mud tank 19, and the backwash mud is introduced.

[0057] The solution outlet of the filter 6 is connected to the inlet of the softening reaction tank 7, and the filtered solution is introduced.

[0058] The mud outlet at the bottom of the softening reaction tank 7 is connected to the inlet of the first mud tank 19, and the bottom sediment mud is introduced.

[0059] The salt solution outlet of the softening reaction tank 7 is connected to the microfiltration membrane 8. The filtered clear liquid is introduced into the inlet of the nanofiltration 9 through the outlet of the microfiltration membrane 8.

[0060] The filtered concentrated liquid containing suspended matter of the microfiltration membrane 8 returns to the softening reaction tank 7 and enters the inlet of the softening reaction tank 7 through the concentrated slurry outlet of the microfiltration membrane 8.

[0061] The nanofiltration 9 intercepts ions with a valence of two or more in the concentrated intercepted solution. The concentrated liquid outlet of the nanofiltration 9 is connected to the inlet of the nanofiltration concentrated water crystallizer 18, and the nanofiltration concentrated liquid is introduced.

[0062] The nanofiltration concentrated water crystallizer 18 is a single-effect or multi-effect evaporation crystallizer, which adopts the gypsum seed method for evaporation crystallization and positive-pressure evaporation. The nanofiltration concentrated water crystallizer of the first mud tank 19 has a primary heating steam inlet and a secondary steam discharge port. The secondary steam discharge port is connected to the heating steam inlet of the fourth reaction tank 27.

[0063] The water produced by the nanofiltration 9 is sodium chloride solution. The water production outlet of the nanofiltration 9 is connected to the inlet of the salt slurry tank 22.

[0064] There is an addition port for sodium chloride at the top inlet of the salt slurry tank 22.

[0065] The nearly saturated salt solution outlet of the salt slurry tank 22 is connected to the inlet of the ammonia absorption tower 10. The ammonia-water vapor mixture at the top of the ammonia absorption tower 10 is introduced into the ammonia absorption tower through the outlet of the shunt 23 and is absorbed by the salt solution.

[0066] The outlet of the salt solution after ammonia absorption in the ammonia absorption tower 10 is connected to the inlet of the first carbonation tower 11; ammonia water, CO2, and sodium chloride react in the first carbonation tower 11 as follows:

[0067] NH 3 +H 2 O+CO 2 +NaCl=NH 4 Cl+NaHCO 3 ↓

[0068] The outlet of the sodium bicarbonate slurry at the bottom of the first carbonation tower 11 is connected to the inlet of the first thickener 14. After the slurry is deposited, it enters the inlet of the filter press 15 from the bottom slurry outlet of the first thickener 14. After vacuum dehydration, sodium bicarbonate enters the dryer 17 and is discharged from the sodium bicarbonate discharge outlet of the dryer 17. The slurry filtered by the filter press 15 enters the mother liquor tank 16, and the outlet of the mother liquor tank 16 is connected to the inlet of the first carbonation tower 11 for returning the mother liquor to the first carbonation tower 11.

[0069] The mother liquor that has not reacted completely in the first carbonation tower 11 enters the second carbonation tower 12 for continuous reaction. The inlet of the second carbonation tower 12 is connected to the outlet of the first carbonation tower 11. The sodium bicarbonate slurry after the reaction in the second carbonation tower 12 enters the second thickener 13 from the bottom outlet. The bottom slurry outlet of the second thickener 13 is connected to the first carbonation tower 11 for returning the bottom slurry of the second thickener 13 to the first carbonation tower 11. The supernatant outlet at the upper part of the second thickener 13 is connected to the inlet of the second carbonation tower 12 to return the supernatant.

[0070] The outlet of the mother liquor after the reaction in the second carbonation tower 12 is connected to the neutralization tower 24. The inlets of ammonia, water, and steam in the neutralization tower 24 are connected to the outlet of the diverter 23.

[0071] In the neutralization tower 24, ammonium bicarbonate in the mother liquor reacts with ammonia to form ammonium carbonate, and the mother liquor forms a system of ammonium carbonate, sodium chloride, and ammonium chloride.

[0072] The outlet of the neutralized mother liquor in the neutralization tower 24 is connected to the inlet of the third reaction tank 25 to introduce the neutralized mother liquor.

[0073] The inlet of the third reaction tank 25 has an outlet for a calcium chloride solution connected to the fourth clarifying tank 28 for introducing the calcium chloride solution. The following reaction occurs in the third reaction tank 25:

[0074] CaCl 2 +(NH4)2CO 3 →2NH 4 Cl+CaCO 3 ↓, calcium ions are precipitated to form calcium carbonate, and the reacted slurry enters the third clarifying tank 26 from the slurry outlet of the third reaction tank 25. After sedimentation, the thickened slurry enters the third slurry tank 21, and calcium carbonate is discharged.

[0075] The supernatant outlet of the third reaction tank 25 is connected to the inlet of the fourth reaction tank 27 to introduce the supernatant.

[0076] There is an inlet for calcium oxide at the top of the fourth reaction tank 27, and the outlets of gaseous ammonia and steam in the fourth reaction tank 27 are communicated with the inlet of the diverter 23.

[0077] There is a secondary steam inlet for reacting with the nanofiltration concentrated water crystallizer 18 at the lower end of the fourth reaction tank 27 for heating.

[0078] The fourth reaction tank 27 is a closed stirring type negative pressure reactor.

[0079] The condensate outlet of the fourth reaction tank 27 is communicated with the inlet of the dissolution tank 3 for dissolving the desulfurized ash in the dissolution tank 3.

[0080] The slurry outlet after the reaction of the fourth reaction tank 27 is connected to the inlet of the fourth clarification tank 28 to introduce the reacted salt solution.

[0081] The reaction occurring in the fourth reaction tank 27 is as follows:

[0082] CaO + H 2 O + 2NH 4 Cl = CaCl 2 + 2NH3↑ + 2H 2 O

[0083] The bottom slurry outlet of the fourth clarification tank 28 discharges the unreacted calcium oxide impurities and other solids into the fourth slurry tank 29, and the solids go out in the form of alkali residue.

[0084] The above description shows and describes several preferred embodiments of the present invention. However, as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the inventive concept described herein through the above teachings or the technology or knowledge in the relevant field. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should fall within the protection scope of the appended claims of the present invention.

Claims

1. A desulfurization ash resource system, characterized in that: include: An oxidation tank (1), wherein the oxidation tank (1) is provided with an inlet for desulfurized ash to enter, the liquid brine outlet inside the oxidation tank (1) is connected to the inlet of the electrolytic oxidation unit (30), and the outlet of the electrolytic oxidation unit (30) is connected to the inlet on the oxidation tank (1); A centrifugal dehydrator (31), wherein the inlet of the centrifugal dehydrator (31) is connected to the salt slurry outlet at the bottom of the oxidation tank (1), the solid outlet of the centrifugal dehydrator (31) is connected to the inlet of the primary dissolution tank (2), and the liquid outlet of the centrifugal dehydrator (31) is connected to the inlet on the oxidation tank (1); a dissolving tank (3), wherein the inlet of the dissolving tank (3) is connected to the outlet of the primary dissolving tank (2), the outlet of the dissolving tank (3) is connected to the inlet of the first reaction tank (4), the outlet of the first reaction tank (4) is connected to the inlet of the first clarification tank (5), the clear liquid outlet of the first clarification tank (5) is connected to the inlet of the filter (6), and the outlet of the filter (6) is connected to the inlet of the softening reaction tank (7); A microfiltration membrane (8), wherein the salt solution outlet of the softening reaction tank (7) is connected to the microfiltration membrane (8), and the clear liquid outlet of the microfiltration membrane (8) is connected to the inlet of the nanofiltration (9); A salt slurry tank (22), wherein the nearly saturated salt solution outlet of the salt slurry tank (22) is connected to the inlet of the ammonia absorption tower (10), the water produced by the nanofiltration (9) is a sodium chloride solution, and the water production outlet of the nanofiltration (9) is connected to the inlet of the salt slurry tank (22); a first carbonization tower (11), wherein the inlet of the first carbonization tower (11) is connected to the outlet of the salt solution after ammonia absorption in the ammonia absorption tower (10), the sodium bicarbonate slurry outlet at the bottom of the first carbonization tower (11) is connected to the inlet of the first thickener (14), the slurry outlet at the bottom of the first thickener (14) is connected to the inlet of an alkali filter (15), the outlet of the alkali filter (15) is connected to the inlet of a dryer (17), the dried sodium bicarbonate is discharged from the dry outlet of the dryer (17), the slurry filtered out of the alkali filter (15) is connected to the inlet of a mother liquid tank (16), the outlet of the mother liquid tank (16) is connected to the inlet of the first carbonization tower (11), and the mother liquid is returned to the first carbonization tower (11); A second carbonization tower (12) for continuously reacting the mother liquor that has not been completely reacted in the first carbonization tower (11), wherein the inlet of the second carbonization tower (12) is connected to the outlet of the first carbonization tower (11), the sodium bicarbonate slurry outlet at the bottom of the second carbonization tower (12) is connected to the inlet of a second thickener (13), the slurry outlet at the bottom of the second thickener (13) is connected to the inlet of the first carbonization tower (11), and the clear liquid outlet at the upper end of the second thickener (13) is connected to the inlet of the second carbonization tower (12).

2. A desulfurization ash resource system according to claim 1, characterized in that: The invention also comprises a neutralization tower (24), wherein the inlet of the neutralization tower (24) is connected to the mother liquor outlet of the second carbonization tower (12), the inlets of ammonia, water and steam in the neutralization tower (24) are connected to the outlet of the splitter (23), the mother liquor outlet of the neutralization tower (24) is connected to the inlet of the third reaction tank (25), the slurry outlet of the third reaction tank (25) is connected to the inlet of the third clarification tank (26), the clear liquid outlet of the third clarification tank (26) is connected to the inlet of the fourth reaction tank (27), the vapor ammonia and water vapor outlets on the fourth reaction tank (27) are connected to the inlet of the splitter (23), the slurry outlet of the fourth reaction tank (27) is connected to the inlet of the fourth clarification tank (28), and the outlet of the calcium chloride solution on the fourth clarification tank (28) is connected to the inlet of the third reaction tank (25).

3. A desulfurization ash resource system according to claim 2, characterized in that: The condensate outlet of the fourth reaction tank (27) is connected to the inlet of the dissolution tank (3).

4. A desulfurization ash resource system according to claim 2, characterized in that: The nanofiltration (9) concentrated liquid outlet is connected to the nanofiltration concentrated water crystallizer (18) inlet, and the nanofiltration concentrated water crystallizer (18) is provided with a mother liquid discharge outlet and a sodium chloride crystal salt outlet.

5. A desulfurization ash resource system according to claim 4, characterized in that: The nanofiltration concentrated water crystallizer (18) is provided with a primary heating steam inlet and a secondary steam outlet, and the secondary steam outlet is connected to the heating steam inlet of the fourth reaction tank (27).

6. A desulfurization ash resource system according to claim 5, characterized in that: The invention also comprises a first mud tank (19), wherein the mud outlet at the bottom of the first clarification tank (5) is connected to the inlet of the first mud tank (19), the outlet of the first mud tank (19) is connected to the inlet of a plate and frame filter press (20), the filtration clear liquid outlet of the plate and frame filter press (20) is connected to the inlet of the first clarification tank (5), a backwash water inlet is reserved at the top of the filter (6), the backwash slurry outlet at the bottom of the filter (6) is connected to the inlet of the first mud tank (19), and the mud outlet at the bottom of the softening reaction tank (7) is connected to the inlet of the first mud tank (19).

7. A desulfurization ash resource system according to claim 5, characterized in that: It also comprises a third mud tank (21), wherein the inlet of the third clarification tank (26) is connected to the mud outlet at the bottom of the third clarification tank (26).

8. A desulfurization ash resource system according to claim 5, characterized in that: The mud outlet at the bottom of the first reaction tank (4) is connected to the inlet of the fourth mud tank (29).

9. A desulfurization ash resource system according to claim 1, characterized in that: A water replenishment inlet is provided on the primary dissolution tank (2), and the supernatant outlet of the primary dissolution tank (2) is connected to the inlet of the softening reaction tank (7).

10. A desulfurization ash resource system according to any one of claims 1 to 9, characterized in that: The filtrate concentrate outlet on the microfiltration membrane (8) is connected to the inlet of the softening reaction tank (7).

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