Device and method for preparing continuous flow coal ash wet desulphurization liquid and coupling acid excitation cementing material

Abstract

The invention discloses a device and a method for preparing a continuous flow coal ash wet desulphurization liquid and a coupling acid excitation cementing material, which are characterized in that coal ash-based filling paste and dedusted flue gas are utilized to synergistically desulfurize and reduce carbon, and coal ash containing free calcium oxide is hydrated and subjected to size mixing, and then is injected into an absorption tower. And gas-liquid high-efficiency mass transfer with reversely flowing dust-removed flue gas is realized in the tower, so that sulfur dioxide removal and carbon dioxide mineralization fixation are synchronously completed, and gypsum and calcium carbonate precipitates are generated. And after the reaction, the desulfurized slurry flows back through a collecting tank to enhance the reaction efficiency, and the liquid negative carbon cementing material can be obtained after dehydration through a liquid cementing material concentration device. Three-dimensional coupling of coal-fired solid waste recycling, flue gas multi-pollutant synergistic treatment and filling material preparation is achieved, the marginal cost of a solid waste treatment and flue gas purification system is remarkably reduced, and the method has the advantages of engineering applicability and environmental economy.

Description

Technical Field

[0001] The present invention belongs to the field of green technology, relates to low-carbon mining of coal and comprehensive utilization of fly ash resources, and particularly relates to a continuous flow fly ash wet desulfurization liquid and a coupled acid-activated gelling material preparation device and method. Background Art

[0002] The trend of on-site conversion and efficient utilization of coal resources has promoted the development of coal-electricity integration projects. However, with the expansion of coal-fired power plant capacity, fly ash and SO 2 , CO 2 The problem of flue gas emission is becoming increasingly prominent. Although the current flue gas desulfurization technology can achieve SO 2 However, there are many defects such as lack of carbon fixation function and high process energy consumption, which leads to CO 2 Indirect emissions have increased instead of decreased. This paradoxical effect of environmental governance shows that building a pollution prevention and control system covering the entire life cycle of coal mining, conversion, and emission management has become a core scientific proposition to resolve the contradiction between resource development and ecological protection and promote the green transformation of the energy structure.

[0003] At the same time, the existing limestone-wet desulfurization technology has certain drawbacks. Its utilization process not only consumes a large amount of calcium oxide, but the decomposition process of limestone also produces carbon dioxide, thereby increasing carbon emissions. The desulfurization gypsum produced by the reaction is also difficult to use effectively. Therefore, a desulfurization and carbon reduction system device is urgently needed to solve the above problems. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a continuous flow fly ash wet desulfurization liquid and a coupled acid-activated cementitious material preparation device and method, thereby realizing continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A continuous flow fly ash wet desulfurization liquid preparation device, comprising a fly ash carbon fixation modification reactor, the fly ash carbon fixation modification reactor is composed of a columnar lower part and a gradually expanding upper part, and its interior is divided from bottom to top into an exchange reaction zone, a solid-liquid separation zone and a clear water zone, wherein the solid-liquid separation zone at least includes a part of the gradually expanding upper part, so as to realize the gradual expansion of the flow cross section;

[0007] The fly ash carbon fixation modification reactor is provided with three material inlets and two material outlets, wherein the three material inlets are respectively a fly ash wet addition port and a desulfurization slurry reflux port for the direct exchange reaction zone and an additive addition port for the direct solid-liquid separation zone, and the two material outlets are respectively a desulfurization liquid flow outlet for the direct clear water zone and a desulfurization slurry discharge port for the direct exchange reaction zone, and the additive addition port is used for adding agents for enhancing carbon dioxide absorption, wherein the desulfurization slurry is obtained by the desulfurization liquid absorbing sulfur dioxide outside the fly ash carbon fixation modification reactor, and the desulfurization liquid is the supernatant after the exchange reaction between the fly ash and the desulfurization slurry and the solid-liquid separation.

[0008] In one embodiment, the fly ash wet addition port penetrates deep into the exchange reaction zone and is at a distance from the bottom surface of the fly ash carbon fixation modification reactor, and the desulfurization slurry reflux port is located below the fly ash wet addition port; the fly ash carbon fixation modification reactor has a built-in ribbon agitator, and the ribbon agitator is at least arranged in the exchange reaction zone.

[0009] In one embodiment, the height of the spiral ribbon agitator is 1 / 2 of the overall height of the fly ash carbon fixation modification reactor, its diameter is 1 / 2 of the diameter of the lower part of the column, the rotation speed is 10-20 rad / min, and the mud-water interface in the solid-liquid separation zone is controlled not to exceed 1 / 2 of the height of the gradually expanding upper part.

[0010] In one embodiment, the maximum diameter of the gradually expanding upper part is expanded to 1.8 to 2.2 times the diameter of the lower part of the column, the distance from the bottom of the solid-liquid separation zone to the top of the clear water zone is 2 to 3 times the diameter of the lower part of the column, the distance between the fly ash wet addition port and the bottom surface of the fly ash carbon fixation modification reactor is equal to 1 / 3 to 1 / 2 of the diameter of the lower part of the column, and the additive addition port goes deep into the solid-liquid separation interface of the solid-liquid separation zone.

[0011] The present invention also provides a continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation device, comprising a fly ash slurry preparation device, an admixture dosing device, an absorption tower, a liquid cementitious material concentration device and the continuous flow fly ash wet desulfurization liquid preparation device;

[0012] The fly ash slurry preparation device is used to prepare fly ash slurry and is connected to the fly ash wet addition port; the admixture addition device has a built-in agent for enhancing carbon dioxide absorption and is connected to the admixture addition port; the absorption tower is connected to the desulfurization liquid outflow port and the desulfurization slurry reflux port, and is used to utilize the dust removal flue gas to make the desulfurization liquid absorb sulfur dioxide and convert it into desulfurization slurry and reflux it; a guide tube is arranged in the liquid gelling material concentration device, the top of the guide tube is an inlet, which is connected to the desulfurization slurry discharge port, and the bottom is in a gradually widening shape along the flow direction. The desulfurization slurry completes solid-liquid separation at the bottom of the liquid gelling material concentration device, and is concentrated to obtain liquid negative carbon gelling material.

[0013] In one embodiment, a water distributor, a splash plate and a flue gas diffusion plate are arranged from top to bottom in the absorption tower, and the bottom of the absorption tower is a collecting tank; the flue gas diffusion plate is connected to the dust removal flue gas, the desulfurization liquid outflow port is connected to the water distributor, and the collecting tank is connected to the desulfurization slurry reflux port.

[0014] In one embodiment, a water collecting weir is arranged in the liquid cementitious material concentration device, and the separated water is collected by the water collecting weir and then transported to the fly ash slurry preparation device, and the concentrated liquid negative carbon cementitious material is discharged from the bottom.

[0015] The present invention further provides a method for preparing a continuous-flow fly ash wet desulfurization coupled acid-activated cementitious material, which is implemented based on the continuous-flow fly ash wet desulfurization liquid preparation device, and comprises the following steps:

[0016] Adding fly ash and water to the fly ash slurry preparation device to prepare fly ash slurry, and feeding the fly ash carbon fixation modification reactor through the fly ash wet feeding port; and feeding the agent for enhancing carbon dioxide absorption;

[0017] The liquid in the clear water area is transported to the absorption tower as the desulfurization liquid, and the dust removal flue gas is introduced into the absorption tower. The desulfurization liquid and the dust removal flue gas are subjected to mass transfer and reaction to realize desulfurization and carbon fixation, and sulfur dioxide is absorbed to be converted into desulfurization slurry; the desulfurization slurry is returned to the fly ash carbon fixation modification reactor, a part of which goes up under stirring and is mixed with the fly ash slurry again, and the other part is directly discharged to the liquid cementitious material concentration device, where separation and concentration occur, and the slurry with reduced water content is the liquid negative carbon cementitious material.

[0018] In one embodiment, the agent for enhancing carbon dioxide absorption is an alcohol amine organic matter, with a dosage of 1 to 10 mg / L. In the fly ash slurry, the solid mass concentration of fly ash is 50 to 60%, and in the exchange reaction zone, the solid mass concentration of fly ash is 10 to 20%, and the reaction time is 5 to 10 minutes; in the absorption tower, the effective countercurrent contact time between the dust removal flue gas and the desulfurization liquid is 8 to 12 seconds, and the liquid-gas ratio is 6 to 15 L / m 3 The downward flow rate of the guide tube is 0.2-0.3 m / s, and the surface load is 20-50 m 3 / m 2 ·h, the residence time is 10 to 30 min, and the solid mass concentration of the obtained liquid negative carbon gelling material is 50 to 60%.

[0019] In one embodiment, a sludge interface meter is provided in the fly ash carbon fixation modification reactor, and the sludge interface meter monitors the sludge level in the solid-liquid separation zone in real time. When the sludge surface tends to rise, the discharge amount of the desulfurization slurry to the liquid gelling material concentration device is increased, and the mud surface in the fly ash carbon fixation modification reactor is controlled to drop. When the sludge surface tends to drop, the discharge amount of the desulfurization slurry to the liquid gelling material concentration device is reduced, and the mud surface in the fly ash carbon fixation modification reactor is controlled to rise, so as to balance the exchange reaction effect and the cleanliness of the desulfurization liquid.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention utilizes fly ash rich in free calcium oxide, uniformly and quantitatively puts it into a fly ash slurry preparation device to mix with water, and then the prepared fly ash slurry enters the fly ash carbon fixation modification reactor and the absorption tower in turn, and transfers and reacts with the boiler dust removal flue gas in the absorption tower to remove sulfur oxides and part of carbon dioxide in the flue gas and generate calcium sulfate and calcium carbonate, thereby achieving the goal of flue gas emission desulfurization and carbon reduction. After the desulfurization liquid reacts with the boiler dust removal flue gas, a desulfurization slurry is obtained, which falls into the collection tank at the bottom of the tower and flows back to the fly ash carbon fixation modification reactor for repeated use; it is then discharged into the liquid gelling material concentration device and treated to reduce the water content to prepare a finished liquid negative carbon gel material. While effectively solving the boiler flue gas emissions, this system greatly saves the comprehensive operating costs of coal-based solid waste and flue gas treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of the continuous flow fly ash cementitious material preparation system of the present invention.

[0024] Among them, 1. Fly ash hopper 2. Screw conveyor quantitative dosing device 3. Tap water meter 4. Fly ash slurry preparation device 5. Reducer motor 1 6. Straight blade stirring paddle 7. Fly ash slurry delivery pipe 8. Fly ash carbon fixation modification reactor 9. Additive dosing device 10. Screw belt stirrer 11. Reducer motor 2 12. Mechanical seal 13. Desulfurization liquid spray pump 14. Flue gas induced draft fan 15. Flue gas diffusion plate 16. Gas distribution head 17. Water distributor 18. Splash plate 19. Backflow water pipe 20. Absorption tower 21. Base 22. Collection tank 23. Demister 24. Liquid gelling material concentration device 25. Diversion tube 26. Mud pump 1 27. Water collecting weir 28. Backflow pump 29. Fly ash wet injection port 30. Additive injection port 31. Desulfurization slurry return port 32. Desulfurization slurry discharge port 33. Desulfurization liquid outflow port 34 Sludge interface instrument 35 Mud pump 2 DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to utilize fly ash to replace limestone for wet desulfurization and to mineralize and seal carbon dioxide, so as to solve the problems existing in the above-mentioned prior art and provide a new way for fly ash utilization and carbon dioxide fixation.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, the present invention first provides a continuous flow fly ash wet desulfurization liquid preparation device, the purpose of which is to use fly ash as a raw material to continuously prepare desulfurization liquid that can be used for flue gas desulfurization and carbon fixation. The main body of the device is a fly ash carbon fixation modification reactor 8, which consists of a columnar lower part and a gradually expanding upper part. The interior is divided from bottom to top into an exchange reaction zone, a solid-liquid separation zone and a clear water zone, wherein the solid-liquid separation zone at least includes a part of the gradually expanding upper part to achieve a gradual expansion of the flow section. Therefore, the clear water zone must be in the gradually expanding upper part. The exchange reaction zone can be only in the lower part of the column, or it can also include a part of the gradually expanding upper part while covering the entire lower part of the column. For example, the maximum diameter of the gradually expanding upper part of the present invention is expanded to 1.8 to 2.2 times the diameter of the lower part of the column, and the distance from the bottom of the solid-liquid separation zone to the top of the clear water zone is 2 to 3 times the diameter of the lower part of the column.

[0029] The fly ash carbon fixation modification reactor 8 has three material inlets and two material outlets, wherein the three material inlets are respectively a fly ash wet addition port 29, a desulfurization slurry return port 31 and an additive addition port 30. The fly ash wet addition port 29 can be arranged at the top and directly connected to the exchange reaction zone, that is, the added fly ash material is directly sent to the exchange reaction zone. The desulfurization slurry return port 31 is arranged at the bottom and directly connected to the exchange reaction zone, that is, the refluxed desulfurization slurry is directly sent to the exchange reaction zone. The additive addition port 30 can be arranged at the top and directly connected to the solid-liquid separation zone, that is, the added additive is directly sent to the solid-liquid separation zone.

[0030] The two material outlets are respectively a desulfurized liquid outlet 33 and a desulfurized slurry outlet 32. The desulfurized liquid outlet 33 can be arranged at the top and directly connected to the clear water area, that is, the liquid in the clear water area is sent out as desulfurized liquid. The desulfurized slurry outlet 32 ​​is arranged at the bottom and directly connected to the exchange reaction area, that is, part of the desulfurized slurry is discharged from the bottom of the exchange reaction area.

[0031] In the present invention, admixtures generally refer to agents that enhance carbon dioxide absorption. Desulfurization liquid refers to a liquid substance used for flue gas desulfurization and carbon fixation, and is the supernatant after the fly ash and desulfurization slurry exchange reaction and solid-liquid separation. The desulfurization slurry is obtained by the desulfurization liquid absorbing sulfur dioxide. The absorption process is also the process of flue gas desulfurization and carbon fixation, which is performed outside the fly ash carbon fixation modification reactor 8. The desulfurization liquid and desulfurization slurry form a cycle, and with the added fly ash, the continuous flow fly ash wet desulfurization liquid preparation described in the present invention is realized.

[0032] Continue to refer Figure 1 In a further embodiment of the present invention, the fly ash wet addition port 29 is extended deep into the exchange reaction zone, that is, there should be a certain distance between its "exit portion" and the bottom surface of the fly ash carbon fixation modification reactor 8. Correspondingly, the desulfurization slurry reflux port 31 is located below the fly ash wet addition port 29, that is, the refluxed desulfurization slurry should be below the "exit portion" of the fly ash wet addition port 29. In order to achieve that a part of the desulfurization slurry goes up to exchange reaction with the fly ash, and the other part is discharged from the desulfurization slurry discharge port 32. For example, the distance between the fly ash wet addition port 29 and the bottom surface of the fly ash carbon fixation modification reactor 8 is equal to 1 / 3 to 1 / 2 of the diameter of the lower part of the column.

[0033] Correspondingly, the present invention places the additive adding port 30 deep into the solid-liquid separation interface of the solid-liquid separation zone, that is, its "exit position" is preferably at the solid-liquid separation interface, so as to directly add the additive to the solid-liquid separation interface. In fact, a better effect can be achieved if the adding point is not lower than the mud-water interface at the upper part of the solid-liquid separation zone.

[0034] Continue to refer Figure 1In a further embodiment of the present invention, a ribbon agitator 10 is built into the fly ash carbon fixation modification reactor 8, and a reduction motor 11 and a mechanical seal 12 are adaptively arranged at the bottom. The ribbon agitator 10 passes through the bottom of the fly ash carbon fixation modification reactor 8, is connected to the reduction motor 11, and the mechanical seal 12 seals the through-passing portion. The ribbon agitator 10 is arranged in the exchange reaction zone, and its function is, on the one hand, to achieve stirring to enhance the exchange reaction between fly ash and desulfurization slurry, and on the other hand, to drive a part of the desulfurization slurry fed from the bottom to move upward. Preferably, the height of the ribbon agitator 10 accounts for 1 / 2 of the overall height of the fly ash carbon fixation modification reactor 8, its diameter is 1 / 2 of the diameter of the lower part of the column, and the rotation speed is 10 to 20 rad / min. The specific rotation speed is preferably to control the mud-water interface in the solid-liquid separation zone not to exceed 1 / 2 of the height of the gradually expanding upper part.

[0035] Reference again Figure 1 Based on the continuous flow fly ash wet desulfurization liquid preparation device, the present invention further provides a continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation device. It includes a fly ash slurry preparation device 4, an admixture dosing device 9, an absorption tower 20, a liquid cementitious material concentration device 24 and the aforementioned continuous flow fly ash wet desulfurization liquid preparation device.

[0036] Among them, the fly ash slurry preparation device 4 is used to prepare fly ash slurry, which is connected to the fly ash wet feeding port 29, and the fly ash slurry is fed into the fly ash carbon fixation modification reactor 8 to achieve wet feeding of fly ash. The admixture feeding device 9 has a built-in agent for enhancing carbon dioxide absorption, and is connected to the admixture feeding port 30, and the admixture is fed into the fly ash carbon fixation modification reactor 8. The absorption tower 20 is connected to the desulfurization liquid outflow port 33 and the desulfurization slurry reflux port 31, and uses the dust removal flue gas to make the desulfurization liquid absorb sulfur dioxide and convert it into desulfurization slurry and reflux, and also uses the desulfurization liquid to achieve desulfurization and carbon fixation of the dust removal flue gas. The liquid gelling material concentration device 24 is used to concentrate the obtained desulfurization slurry to obtain the final product. A guide tube 25 is arranged inside, and the top of the guide tube 25 is an inlet, which is connected to the desulfurization slurry discharge port 32, and the bottom is in a gradually widening shape along the flow direction, and has a certain distance from the bottom surface of the liquid gelling material concentration device 24. The desulfurized slurry flows in from the top of the guide tube 25 and flows out from the bottom, and completes solid-liquid separation at the bottom of the liquid gelling material concentration device 24, and is concentrated to obtain the final product - liquid negative carbon gelling material. Obviously, the guide tube 25 is preferably arranged at the central position of the liquid gelling material concentration device 24.

[0037] Continue to refer Figure 1In a further embodiment of the present invention, a fly ash feeding port and a water feeding port are provided at the top of the fly ash slurry preparation device 4, and a fly ash slurry outlet is provided at the bottom. The fly ash feeding port is connected to the outlet of the screw conveying quantitative feeding device 2, and the fly ash stored in the fly ash hopper 1 is fed into the fly ash slurry preparation device 4 through the screw conveying quantitative feeding device 2. The water feeding port is connected to the water delivery pipe. Obviously, in order to control the water volume, a water meter 3 should be provided on the water delivery pipe. The fly ash slurry outlet is connected to the fly ash wet feeding port 29 through the fly ash slurry delivery pipe 7, and the prepared fly ash slurry is fed into the exchange reaction zone of the fly ash carbon fixation modification reactor 8.

[0038] In order to achieve a good fly ash slurry preparation effect, a straight-blade stirring paddle 6 is also provided in the fly ash slurry preparation device 4. The straight-blade stirring paddle 6 is driven by a reduction motor 5 on the top of the fly ash slurry preparation device 4 to stir the mixed fly ash hopper 1 and water to continuously prepare fly ash slurry. For example, the blade diameter of the straight-blade stirring paddle 6 is 2 / 3 to 3 / 4 of the inner diameter of the fly ash slurry preparation device 4, and the stirring speed is 20 to 50 rad / min. Under this parameter, a qualified fly ash slurry with uniform composition can be obtained, and the energy consumption is low.

[0039] Continue to refer Figure 1 In a further embodiment of the present invention, a water distributor 17, a splash plate 18 and a flue gas diffusion plate 15 are arranged from top to bottom in the absorption tower 20. The bottom of the absorption tower 20 is funnel-shaped and can be used as a collection tank 22. The splash plate 18 can be multi-layered, and three layers are shown in the figure. The flue gas diffusion plate 15 receives the dust removal flue gas, and a plurality of air distribution heads 16 can be arranged thereon to evenly release the dust removal flue gas. A flue gas induced draft fan 14 is arranged on the dust removal flue gas pipeline to provide power for delivering the dust removal flue gas to the flue gas diffusion plate 15. The desulfurization liquid outflow port 33 is connected to the water distributor 17 through the desulfurization liquid delivery pipeline, and a desulfurization liquid spray pump 13 is arranged on the desulfurization liquid delivery pipeline to provide delivery power. The collection tank 22 is then connected back to the desulfurization slurry reflux port 31 to realize the reflux of the desulfurization slurry to the fly ash carbon fixation modification reactor 8. The present invention installs the absorption tower 20 on a base 21, and provides a demister 23 inside the absorption tower 20 above the water distributor 17, so as to demister the flue gas after the reaction and then discharge it in an organized manner from the top.

[0040] Continue to refer Figure 1In a further embodiment of the present invention, a water collecting weir 27 is provided in the liquid cementitious material concentration device 24, and the water collecting weir 27 is located at an upper position. The desulfurized slurry discharged from the desulfurized slurry discharge port 32 enters the guide tube 25 from the desulfurized slurry pipeline, and a mud pump 2 35 is provided on the desulfurized slurry pipeline to provide discharge power. The desulfurized slurry flows out from the bottom of the guide tube 25 and is gradually concentrated. The upward separated water is collected by the water collecting weir 27 and transported to the fly ash slurry preparation device 4 through the return water pipeline 19 as water for preparing the fly ash slurry. A return water pump 28 is provided on the return water pipeline 19 to provide return power. The concentrated liquid negative carbon cementitious material is discharged from the bottom of the liquid cementitious material concentration device 24 and collected for use. Due to the high concentration, a mud pump 26 can be provided at its discharge port.

[0041] According to the above device, the method for preparing a continuous flow fly ash wet desulfurization coupled with acid-activated cementitious material of the present invention mainly comprises the following steps:

[0042] Step 1, add fly ash and water to the fly ash slurry preparation device 4 to prepare fly ash slurry. For example, the solid mass concentration of fly ash in the fly ash slurry is 50-60%. The fly ash slurry is added to the fly ash carbon fixation modification reactor 8 through the fly ash wet addition port 29, and the agent for enhancing carbon dioxide absorption is added through the additive addition port. For example, the agent is an alcohol amine organic matter, which is used to enhance the carbon dioxide mass transfer and absorption efficiency of the desulfurization liquid, such as triethanolamine, and the addition amount is 1-10 mg / L.

[0043] Step 2, the clear liquid in the clear water area is transported to the absorption tower 20 as a desulfurization liquid, and the dust removal flue gas is introduced into the absorption tower 20. In the absorption tower 20, the desulfurization liquid and the dust removal flue gas are subjected to mass transfer and reaction to achieve desulfurization and carbon fixation, and sulfur dioxide is absorbed to be converted into a desulfurization slurry. The desulfurization slurry is returned to the fly ash carbon fixation modification reactor 8, a part of which is stirred and moved upward to mix with the fly ash slurry again, and the other part is directly discharged to the liquid cementitious material concentration device 24, where separation and concentration occur, and the slurry with reduced water content is the liquid negative carbon cementitious material.

[0044] Furthermore, when the specific structure of the aforementioned absorption tower 20 is adopted, the desulfurization and carbon fixation process therein is as follows: the clear liquid in the clear water area is transported to the water distributor 17 as the desulfurization liquid at the required flow rate through the desulfurization liquid spray pump 13, and the dust-removed flue gas is transported to the flue gas diffusion plate 15 and the air distribution head 16 through the flue gas induced draft fan 14, so that the flue gas to be desulfurized is evenly distributed. The desulfurization liquid is evenly dispersed by the water distributor 17 and falls to the bottom of the tower, and flows through the three-layer splash plate 18 in sequence. During the process, it contacts the dust-removed flue gas in countercurrent, so that the sulfur dioxide, carbon dioxide and other gases in the flue gas diffuse, transfer, absorb and fix with the desulfurization liquid droplets, and then the flue gas is desulfurized and carbon fixed, and the sulfur dioxide and carbon dioxide in the flue gas are removed, so that the desulfurized flue gas discharged continues to move upward and passes through the demister 23 to remove water vapor and then is discharged in an organized manner. The desulfurized slurry obtained after absorbing sulfur dioxide finally falls into the collection tank 22, and then flows back to the fly ash carbon fixation modification reactor 8 through the pipeline. In the exchange reaction zone, a portion of the desulfurized slurry is mixed with the fly ash slurry again under the action of the ribbon agitator 10, and the other portion of the desulfurized slurry is discharged to the liquid gelling material concentration device 24, where it is separated and concentrated, and the slurry with reduced water content is the liquid negative carbon gelling material. For example, the effective countercurrent contact time between the dust removal flue gas and the desulfurized liquid is 8 to 12 seconds, and the liquid-gas ratio is 6 to 15 L / m 3 .

[0045] Specifically, in the fly ash carbon fixation modification reactor 8, the fly ash slurry input from the fly ash slurry preparation device 4 and the desulfurization slurry refluxed from the absorption tower 24 are directly mixed at the bottom, and the desulfurization slurry obtained after the desulfurization liquid absorbs sulfur dioxide and carbon dioxide reacts with the calcium oxide and magnesium oxide particles in the fly ash slurry and adsorbs on the surface of the fly ash particles, completing the phase migration and fixation of carbon dioxide and sulfur dioxide in the desulfurization slurry. At the same time, the calcium oxide and magnesium oxide that have not reacted completely in the fly ash slurry are further dissolved in the desulfurization slurry, and finally the desulfurization liquid is regenerated, and the separation of the desulfurization liquid and the fly ash slurry is realized through the solid-liquid separation zone with a gradually expanding flow area during the upward flow. For example, the solid mass concentration of the fly ash in the exchange reaction zone is 10-20%, and the reaction time is 5-10 minutes.

[0046] Specifically, in the liquid cementitious material concentration device 24, the desulfurized slurry flows from top to bottom in the guide tube 25, and is separated and concentrated under the action of the guide tube 25. The slurry with reduced water content is concentrated at the bottom, and the solid-liquid separation is completed at the bottom of the device. The separated water generated during the slurry concentration process is collected by the water collecting weir 27 at the top of the device and then lifted to the fly ash slurry preparation device 4 by the reflux pump 28. The slurry concentrated to an appropriate water content at the bottom is the finished liquid negative carbon cementitious material, which is transported to the use point by the mud pump 26. For example, the downward flow rate of the desulfurized slurry in the guide tube 25 is 0.2-0.3 m / s, and the surface load is 20-50 m 3 / m 2h, the residence time is 10 to 30 min, and the solid mass concentration of the liquid negative carbon gelling material finally obtained is 50 to 60%.

[0047] Furthermore, the present invention sets a sludge interface meter 34 in the fly ash carbon fixation modification reactor 8. The sludge interface meter 34 can be installed on the top of the reactor, and it can monitor the sludge level in the solid-liquid separation zone in real time. When the mud surface tends to rise, the discharge amount of the desulfurization slurry to the liquid gelling material concentration device 24 is increased to control the mud surface in the fly ash carbon fixation modification reactor 8 to drop. Specifically, it can be achieved by increasing the rotation speed of the ribbon agitator 10, increasing the power of the mud pump 2 35, and other methods. When the mud surface tends to drop, the discharge amount of the desulfurization slurry to the liquid gelling material concentration device 24 is reduced to control the mud surface in the fly ash carbon fixation modification reactor 8 to rise, which can be achieved by reducing the rotation speed of the ribbon agitator 10, reducing the power of the mud pump 2 35, and other methods. In this way, a balance between the exchange reaction effect and the cleanliness of the desulfurization liquid can be achieved.

[0048] In a specific embodiment of the present invention, the fly ash carbon fixation modification reactor 8 has a bottom diameter of 8 meters and a height of 10 meters, a clear water zone diameter of 16 meters and a height of 8 meters, and consumes 210 to 260 tons of fly ash per hour. The absorption tower 20 has a diameter of 8 meters and a total height of 35 meters, and can process 1.3 to 1.7×10 7 m 3 Coal combustion flue gas. The liquid gelling material concentration device 24 has a diameter of 8 meters and a height of 12 meters, and produces 400 to 500 tons of gelling material per hour.

[0049] In this example, the dust-removed flue gas from Fuxian Power Plant and the fly ash from the power plant were used for the experiment. The SO 2 The converted concentration is about 1500mg / m 3 The main components of fly ash are CaO, SiO 2 According to the present invention, the desulfurized flue gas discharged from the absorption tower is tested, wherein SO 2 The converted concentration is 33 mg / m 3 , less than 35mg / m 3 , meeting the ultra-clean emission requirements, the desulfurization efficiency reaches 97.8%, and at the same time it can be calculated that the carbon fixation capacity of the fly ash slurry is approximately 56.16kg / t.

[0050] In summary, the present invention realizes the integration of fly ash and dust removal flue gas for synergistic desulfurization and carbon reduction. The fly ash containing free calcium oxide is quantitatively transported to the fly ash slurry preparation device for hydration and slurry adjustment by a precise metering feeding system, and then injected into the absorption tower through the multi-stage mixing intensification system and the pressurized conveying unit in the fly ash carbon fixation modification reactor 8. In the stepped porous distribution plate system formed by the splash plate 18 in the tower, the slurry and the counter-flowing boiler flue gas realize efficient gas-liquid mass transfer, and SO2 Removal and CO 2 Mineralization fixation generates gypsum and calcium carbonate precipitates. The desulfurized slurry after the reaction is collected and refluxed through the bottom collection tank to enhance the reaction efficiency, and can be dehydrated by the liquid gelling material concentration device 24 and transported to the paste filling station and other places for use. The overflow liquid is closed-loop recycled for the fly ash slurry preparation process. This process innovation realizes the three-dimensional coupling of coal-fired solid waste resource utilization, coordinated treatment of multiple pollutants in flue gas, and preparation of filling materials, significantly reducing the marginal cost of solid waste disposal and flue gas purification systems, and has both engineering applicability and environmental economic advantages.

[0051] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0052] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A continuous flow fly ash wet desulfurization liquid preparation device, characterized in that: The fly ash carbon fixation modification reactor (8) comprises a columnar lower part and a gradually expanding upper part, wherein the interior of the fly ash carbon fixation modification reactor (8) is divided from bottom to top into an exchange reaction zone, a solid-liquid separation zone and a clear water zone, wherein the solid-liquid separation zone at least includes a part of the gradually expanding upper part, so as to realize a gradually expanding flow cross section; The fly ash carbon fixation modification reactor (8) is provided with three material inlets and two material outlets. The three material inlets are respectively a fly ash wet addition port (29) and a desulfurization slurry return port (31) for the direct exchange reaction zone and an additive addition port (30) for the direct solid-liquid separation zone. The two material outlets are respectively a desulfurization liquid outflow port (33) for the direct clear water zone and a desulfurization slurry discharge port (32) for the direct exchange reaction zone. The additive addition port (30) is used for adding a reagent for enhancing carbon dioxide absorption. The desulfurization slurry is obtained by the desulfurization liquid absorbing sulfur dioxide outside the fly ash carbon fixation modification reactor (8). The desulfurization liquid is the supernatant after the fly ash and the desulfurization slurry exchange reaction and solid-liquid separation.

2. The continuous flow fly ash wet desulfurization liquid preparation device according to claim 1 is characterized in that: The fly ash wet addition port (29) extends deep into the exchange reaction zone and is at a distance from the bottom surface of the fly ash carbon fixation modification reactor (8); the desulfurization slurry reflux port (31) is located below the fly ash wet addition port (29); the fly ash carbon fixation modification reactor (8) has a built-in ribbon agitator (10), and the ribbon agitator (10) is at least arranged in the exchange reaction zone.

3. The continuous flow fly ash wet desulfurization liquid preparation device according to claim 2 is characterized in that: The height of the ribbon agitator (10) is 1 / 2 of the overall height of the fly ash carbon fixation modification reactor (8), and its diameter is 1 / 2 of the diameter of the cylindrical lower part. The rotation speed is 10-20 rad / min, and the mud-water interface in the solid-liquid separation zone is controlled not to exceed 1 / 2 of the height of the gradually expanding upper part.

4. The continuous flow fly ash wet desulfurization liquid preparation device according to claim 1, 2 or 3, characterized in that: The maximum diameter of the gradually expanding upper part is expanded to 1.8 to 2.2 times the diameter of the lower part of the column, the distance from the bottom of the solid-liquid separation zone to the top of the clear water zone is 2 to 3 times the diameter of the lower part of the column, the distance between the fly ash wet addition port (29) and the bottom surface of the fly ash carbon fixation modification reactor (8) is equal to 1 / 3 to 1 / 2 of the diameter of the lower part of the column, and the additive addition port (30) is deep into the solid-liquid separation interface position of the solid-liquid separation zone.

5. A continuous flow fly ash wet desulfurization coupled with acid-activated cementitious material preparation device, characterized in that: It comprises a fly ash slurry preparation device (4), an admixture dosing device (9), an absorption tower (20), a liquid gelling material concentration device (24), and a continuous flow fly ash wet desulfurization liquid preparation device as claimed in any one of claims 1 to 4; The fly ash slurry preparation device (4) is used to prepare fly ash slurry and is connected to the fly ash wet addition port (29); the admixture addition device (9) has a built-in agent for enhancing carbon dioxide absorption and is connected to the admixture addition port (30); the absorption tower (20) is connected to the desulfurization liquid outflow port (33) and the desulfurization slurry return port (31) and is used to utilize the dust removal flue gas to make the desulfurization liquid absorb sulfur dioxide and convert it into desulfurization slurry and return it; A guide tube (25) is arranged in the liquid gelling material concentrating device (24). The top of the guide tube (25) is an inlet, which is connected to the desulfurized slurry discharge port (32), and the bottom is gradually widened along the flow direction. The desulfurized slurry completes solid-liquid separation at the bottom of the liquid gelling material concentrating device (24) and is concentrated to obtain liquid negative carbon gelling material.

6. The continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation device according to claim 5 is characterized in that: A water distributor (17), a water splash plate (18) and a flue gas diffusion plate (15) are arranged from top to bottom in the absorption tower (20), and the bottom of the absorption tower (20) is a collecting tank (22); the flue gas diffusion plate (15) is connected to the dust removal flue gas, the desulfurization liquid outflow port (33) is connected to the water distributor (17), and the collecting tank (22) is connected to the desulfurization slurry reflux port (31).

7. The continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation device according to claim 5 is characterized in that: A water collecting weir (27) is arranged in the liquid cementitious material concentration device (24), and the separated water is collected by the water collecting weir (27) and then transported to the fly ash slurry preparation device (4), and the concentrated liquid negative carbon cementitious material is discharged from the bottom.

8. A method for preparing a continuous-flow fly ash wet desulfurization coupled with acid-activated cementitious material, which is realized based on the continuous-flow fly ash wet desulfurization liquid preparation device according to any one of claims 5 to 7, characterized in that: The steps include: Adding fly ash and water to the fly ash slurry preparation device (4) to prepare fly ash slurry, and injecting the fly ash carbon fixation modification reactor (8) through the fly ash wet injection port (29); and injecting the agent for enhancing carbon dioxide absorption; The liquid in the clear water zone is transported to the absorption tower (20) as a desulfurization liquid, and the dust removal flue gas is introduced into the absorption tower (20). The desulfurization liquid and the dust removal flue gas are subjected to mass transfer and reaction to achieve desulfurization and carbon fixation, and sulfur dioxide is absorbed to be converted into a desulfurization slurry; the desulfurization slurry is refluxed to the fly ash carbon fixation modification reactor (8), a part of which is upwardly moved under stirring to be mixed with the fly ash slurry again, and the other part is directly discharged to the liquid cementitious material concentration device (24), where separation and concentration occur, and the slurry with reduced water content is the liquid negative carbon cementitious material.

9. The method for preparing continuous flow fly ash wet desulfurization coupled acid-activated cementitious material according to claim 8, characterized in that: The agent for enhancing carbon dioxide absorption is an alcohol amine organic matter, with a dosage of 1-10 mg / L. In the fly ash slurry, the solid mass concentration of fly ash is 50-60%, in the exchange reaction zone, the solid mass concentration of fly ash is 10-20%, and the reaction time is 5-10 minutes; in the absorption tower (20), the effective countercurrent contact time between the dust removal flue gas and the desulfurization liquid is 8-12 seconds, and the liquid-gas ratio is 6-15 L / m 3 The downward flow rate of the guide tube (25) is 0.2 to 0.3 m / s, and the surface load is 20 to 50 m 3 / m 2 ·h, the residence time is 10 to 30 min, and the solid mass concentration of the obtained liquid negative carbon gelling material is 50 to 60%.

10. The method for preparing continuous flow fly ash wet desulfurization coupled acid-activated cementitious material according to claim 8, characterized in that: The fly ash carbon fixation modification reactor (8) is provided with a sludge interface meter (34), and the sludge interface meter (34) monitors the sludge liquid level in the solid-liquid separation zone in real time. When the sludge surface tends to rise, the discharge amount of the desulfurization slurry to the liquid gelling material concentration device (24) is increased to control the sludge surface in the fly ash carbon fixation modification reactor (8) to drop. When the sludge surface tends to drop, the discharge amount of the desulfurization slurry to the liquid gelling material concentration device (24) is reduced to control the sludge surface in the fly ash carbon fixation modification reactor (8) to rise, so as to balance the exchange reaction effect and the cleanliness of the desulfurization liquid.

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