Continuous-flow wet desulfurization liquid of fly ash and coupling acid-activated cementitious material preparation device and method

Abstract

The application discloses a kind of continuous flow fly ash wet desulfurization liquid and coupling acid excitation cementing material preparation device and method, utilize fly ash-based filling paste and dust removal flue gas synergistic desulfurization and carbon reduction, carry out hydration and mixing of fly ash containing free calcium oxide, then inject into absorption tower.In tower and reverse flow dust removal flue gas realize gas-liquid efficient mass transfer, complete sulfur dioxide removal and carbon dioxide mineralization fixation simultaneously, generate gypsum and calcium carbonate precipitate.After reaction, desulfurization slurry is collected by tank backflow to strengthen reaction efficiency, and can be dehydrated by liquid cementing material concentration device to obtain liquid carbon-negative cementing material.The application realizes three-dimensional coupling of coal-fired solid waste resource utilization, flue gas multi-pollutant synergistic treatment and filling material preparation, significantly reduces the marginal cost of solid waste disposal and flue gas purification system, and has engineering applicability and environmental and economic advantage.

Description

TECHNICAL FIELD

[0001] The application 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 preparation device and method of coupling acid-activated cementitious materials. BACKGROUND

[0002] The trend of in-situ conversion and efficient utilization of coal resources promotes the development of coal-electricity integration projects. However, with the expansion of coal-fired power plant capacity, the problems of fly ash and flue gas containing SO2 and CO2 emissions are increasingly prominent. Although the existing flue gas desulfurization technology can achieve the goal of SO2 emission reduction, it generally has defects such as lack of carbon fixation function and high process energy consumption, resulting in an increase in indirect CO2 emissions. This paradoxical effect of environmental governance shows that building a full life cycle pollution prevention and control system covering coal mining, conversion, and emission treatment has become a core scientific proposition to resolve the contradiction between resource development and ecological protection and promote the green transformation of energy structure.

[0003] At the same time, the existing limestone-wet desulfurization technology has certain drawbacks, and in its utilization process, not only a large amount of calcium oxide is consumed, but also carbon dioxide is generated in the decomposition process of limestone, thereby increasing carbon emissions, and the desulfurization gypsum generated in the reaction is also difficult to effectively utilize, thereby an urgent need exists for a desulfurization and carbon reduction system device to solve the above problems. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a continuous flow fly ash wet desulfurization liquid and a preparation device and method of coupling acid-activated cementitious materials, which realizes continuous flow fly ash wet desulfurization coupling acid-activated preparation of cementitious materials.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application 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 cylindrical lower part and a gradually expanding upper part, and its inside is divided into an exchange reaction zone, a solid-liquid separation zone and a clear water zone from bottom to top, wherein the solid-liquid separation zone at least contains a part of the gradually expanding upper part, and the flow cross section is gradually expanded;

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

[0008] In one embodiment, the fly ash wet feeding port penetrates into the exchange reaction zone and is away from the bottom surface of the fly ash carbon fixation modification reactor, and the desulfurization slurry backflow port is located below the fly ash wet feeding port; the fly ash carbon fixation modification reactor is internally provided with a spiral ribbon agitator, and the spiral ribbon agitator is arranged at least in the exchange reaction zone.

[0009] In one embodiment, the height of the spiral ribbon agitator accounts for 1 / 2 of the overall height of the fly ash carbon fixation modification reactor, the diameter of the spiral ribbon agitator is 1 / 2 of the diameter of the lower cylindrical part, the rotating speed is 10-20 rad / min, and the slurry interface of the solid-liquid separation zone is controlled to be not more than 1 / 2 of the height of the gradually widened upper part.

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

[0011] The application also provides a continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation device, which comprises a fly ash slurry preparation device, an additive feeding 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 for preparing fly ash slurry and is connected with the fly ash wet feeding port; the additive feeding device is internally provided with a medicament for strengthening carbon dioxide absorption and is connected with the additive feeding port; the absorption tower is connected with the desulfurization liquid flow outlet and the desulfurization slurry backflow port and is used for converting desulfurization liquid into desulfurization slurry by using dust removal flue gas to absorb sulfur dioxide and backflowing; the liquid cementitious material concentration device is internally provided with a flow guide cylinder, the top of the flow guide cylinder is an inlet and is communicated with the desulfurization slurry discharge outlet, and the bottom of the flow guide cylinder is in the shape of a gradually widened shape along the flow direction, the desulfurization slurry is subjected to solid-liquid separation at the bottom of the liquid cementitious material concentration device, and liquid negative carbon cementitious material is obtained by concentration.

[0013] In one embodiment, the absorption tower is provided with a water distributor, a splash plate and a flue gas diffusion plate from top to bottom, and the bottom of the absorption tower is a collection tank; the flue gas diffusion plate is connected to the dust removal flue gas, the desulfurization liquid outlet is connected to the water distributor, and the collection tank is connected to the desulfurization slurry backflow port.

[0014] In one embodiment, a water collecting weir is arranged in the liquid gel 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 carbon-negative gel material is discharged from the bottom.

[0015] The application further provides a continuous flow fly ash wet desulfurization coupled acid-activated gel material preparation method, which is realized based on the continuous flow fly ash wet desulfurization liquid preparation device and includes the following steps:

[0016] Fly ash and water are added to the fly ash slurry preparation device to prepare fly ash slurry, which is input into the fly ash carbon fixation modification reactor through the fly ash wet addition port; and the medicament for strengthening carbon dioxide absorption is input.

[0017] The liquid in the clean water zone is transported to the absorption tower as desulfurization liquid, and dust removal flue gas is input into the absorption tower, mass transfer and reaction are performed between the desulfurization liquid and the dust removal flue gas to realize desulfurization and carbon fixation, and sulfur dioxide is absorbed to be converted into desulfurization slurry; the desulfurization slurry is backflowed to the fly ash carbon fixation modification reactor, a part of which is mixed with fly ash slurry again under the action of stirring, and the other part is directly discharged to the liquid gel material concentration device to separate and concentrate, so that the slurry with reduced water content is the liquid carbon-negative gel material.

[0018] In one embodiment, the medicament for strengthening carbon dioxide absorption is an alcohol amine organic substance, and the addition amount is 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 min; in the absorption tower, the effective countercurrent contact time of the dust removal flue gas and the desulfurization liquid is 8-12 s, and the liquid-gas ratio is 6-15 L / m 3 ; the descending flow rate of the draft tube is 0.2-0.3 m / s, the surface load is 20-50 m 3 / m 2 ·h, the residence time is 10-30 min, and the solid mass concentration of the obtained liquid carbon-negative gel material is 50-60%.

[0019] In one embodiment, the fly ash carbon sequestration modification reactor is provided with a sludge interface instrument, which monitors the sludge liquid level of the solid-liquid separation zone in real time, and when the sludge surface has a rising trend, the discharge amount of the desulfurization slurry to the liquid cementitious material concentration device is increased to control the sludge surface in the fly ash carbon sequestration modification reactor to decrease, and when the sludge surface has a decreasing trend, the discharge amount of the desulfurization slurry to the liquid cementitious material concentration device is reduced to control the sludge surface in the fly ash carbon sequestration modification reactor to increase, so as to balance the exchange reaction effect and the cleaning degree of the desulfurization liquid.

[0020] Compared with the prior art, the beneficial effects of the present application are:

[0021] The present application utilizes fly ash rich in free calcium oxide, which is uniformly and quantitatively fed into a fly ash slurry preparation device and mixed with water, and then the prepared fly ash slurry is sequentially fed into a fly ash carbon sequestration modification reactor, an absorption tower, 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, achieving the goal of flue gas emission desulfurization and carbon reduction. The desulfurization liquid reacts with the boiler dust removal flue gas to obtain desulfurization slurry, which falls into the collection tank at the bottom of the tower and is returned to the fly ash carbon sequestration modification reactor for repeated use; then it is discharged into the liquid cementitious material concentration device, treated to reduce the water content, and then prepared into finished liquid negative carbon cementitious material. The system effectively solves the problem of boiler flue gas emission while greatly saving the comprehensive operation cost of coal-based solid waste and flue gas treatment. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0023] Figure 1 The structure schematic diagram of the continuous flow fly ash cementitious material preparation system of the present application.

[0024] 1. fly ash bucket 2. screw conveying quantitative dosing device 3. tap water meter 4. fly ash slurry preparation device 5. speed reducer motor 6. straight-blade stirring paddle 7. fly ash slurry conveying pipe 8. fly ash carbon fixation modification reactor 9. additive dosing device 10. screw belt stirrer 11. speed reducer motor 2 12. mechanical seal 13. desulfurization liquid spraying pump 14. flue gas induced draft fan 15. flue gas diffusion plate 16. air distribution head 17. water distributor 18. splash plate 19. backflow water pipe 20. absorption tower 21. base 22. collection tank 23. demister 24. liquid cementitious material concentration device 25. flow guide cylinder 26. slurry pump 1 27. water collecting weir 28. backflow pump 29. fly ash wet dosing port 30. additive dosing port 31. desulfurization slurry backflow port 32. desulfurization slurry discharge port 33. desulfurization liquid flow outlet 34. sludge interface instrument 35. slurry pump 2 DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

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

[0027] In order to make the above-mentioned purposes, characteristics and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0028] As shown in Figure 1 The present application first provides a continuous flow fly ash wet desulfurization liquid preparation device, which aims to continuously prepare desulfurization liquid that can be used for flue gas desulfurization and carbon fixation by using fly ash as raw material. The main body of the device is a fly ash carbon fixation modification reactor 8, which is composed of a columnar lower part and a gradually expanding upper part. The inside of the fly ash carbon fixation modification reactor 8 is divided into an exchange reaction zone, a solid-liquid separation zone and a clear water zone from bottom to top. The solid-liquid separation zone at least includes a part of the gradually expanding upper part to realize the gradual expansion of the flow cross section. Therefore, the clear water zone is necessarily in the gradually expanding upper part. The exchange reaction zone can be only in the columnar lower part, or can include a part of the gradually expanding upper part while covering the whole columnar lower part. Exemplarily, the maximum diameter of the gradually expanding upper part of the present application is expanded to 1.8-2.2 times of the diameter of the columnar lower part, and the distance from the bottom of the solid-liquid separation zone to the top of the clear water zone is 2-3 times of the diameter of the columnar lower part.

[0029] The fly ash carbon fixation and modification reactor 8 has three material inlets and two material outlets. The three material inlets are a wet fly ash inlet 29, a desulfurization slurry return inlet 31, and an additive inlet 30. The wet fly ash inlet 29 can be located at the top and directly connected to the exchange reaction zone, meaning that the added fly ash material is directly fed into the exchange reaction zone. The desulfurization slurry return inlet 31 is located at the bottom and directly connected to the exchange reaction zone, meaning that the returned desulfurization slurry is directly fed into the exchange reaction zone. The additive inlet 30 can be located at the top and directly connected to the solid-liquid separation zone, meaning that the added additive is directly fed into the solid-liquid separation zone.

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

[0031] In this invention, the additive generally refers to a reagent that enhances carbon dioxide absorption. The desulfurization liquid refers to the liquid substance used for desulfurization and carbon fixation of flue gas; it is the supernatant after the exchange reaction between fly ash and desulfurization slurry and subsequent solid-liquid separation. The desulfurization slurry is obtained by absorbing sulfur dioxide from the desulfurization liquid; this absorption process is also the process of desulfurization and carbon fixation of flue gas, and it is performed outside the fly ash carbon fixation modification reactor 8. The desulfurization liquid and desulfurization slurry form a cycle, and together with the added fly ash, realize the preparation of continuous-flow wet fly ash desulfurization liquid as described in this invention.

[0032] Continue to refer to Figure 1 In a further embodiment of the present invention, the wet fly ash inlet 29 extends into the exchange reaction zone, meaning that its "outlet" should be at a certain distance from the bottom surface of the fly ash carbonization modification reactor 8. Correspondingly, the desulfurization slurry return outlet 31 is located below the wet fly ash inlet 29, meaning the returned desulfurization slurry should be below the "outlet" of the wet fly ash inlet 29. This allows a portion of the desulfurization slurry to rise and exchange with the fly ash, while the other portion is discharged from the desulfurization slurry outlet 32. For example, the distance between the wet fly ash inlet 29 and the bottom surface of the fly ash carbonization 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 admixture inlet 30 deep into the solid-liquid separation interface of the solid-liquid separation zone; that is, its "outlet" is preferably located at the solid-liquid separation interface, so as to directly add the admixture to the solid-liquid separation interface. In fact, better results can be obtained when the addition point is not lower than the mud-water interface at the upper part of the solid-liquid separation zone.

[0034] Continue to refer to Figure 1In a further embodiment of the present application, a screw stirrer 10 is arranged in the fly ash carbon sequestration modification reactor 8, and a speed reducer 11 and a mechanical seal 12 are arranged at the bottom of the fly ash carbon sequestration modification reactor 8. The screw stirrer 10 penetrates the bottom of the fly ash carbon sequestration modification reactor 8 and is connected to the speed reducer 11, and the mechanical seal 12 seals the penetration. The screw stirrer 10 is arranged in the exchange reaction zone, which has the functions of stirring to enhance the exchange reaction between the fly ash and the desulfurization slurry, and driving a part of the desulfurization slurry fed from the bottom to flow upward. Preferably, the height of the screw stirrer 10 accounts for 1 / 2 of the overall height of the fly ash carbon sequestration modification reactor 8, the diameter of the screw stirrer 10 is 1 / 2 of the diameter of the lower cylindrical part, and the rotation speed is 10-20 rad / min. The specific rotation speed is preferably controlled to make the sludge-water interface of the solid-liquid separation zone not exceed 1 / 2 of the height of the gradually widened upper part.

[0035] Referring again to Figure 1 Based on the continuous flow fly ash wet desulfurization liquid preparation device, the present application further provides a continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation device. The device comprises a fly ash slurry preparation device 4, an additive feeding 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] The fly ash slurry preparation device 4 is used to prepare fly ash slurry, which is connected to a fly ash wet feeding port 29 to feed the fly ash slurry into the fly ash carbon sequestration modification reactor 8, thereby realizing wet feeding of fly ash. The additive feeding device 9 is internally provided with a medicament for strengthening carbon dioxide absorption, which is connected to an additive feeding port 30 to feed the additive into the fly ash carbon sequestration modification reactor 8. The absorption tower 20 is connected to a desulfurization liquid outlet 33 and a desulfurization slurry reflux port 31, which uses the dedusting flue gas to convert the desulfurization liquid into desulfurization slurry and make it flow back, and also uses the desulfurization liquid to realize desulfurization and carbon sequestration of the dedusting flue gas. The liquid cementitious material concentration device 24 is used to concentrate the obtained desulfurization slurry to obtain the final product. A flow guide cylinder 25 is arranged in the liquid cementitious material concentration device 24, the top of the flow guide cylinder 25 is an inlet connected to a desulfurization slurry discharge port 32, the bottom is in the shape of a gradually widening shape along the flow direction, and has a certain spacing from the bottom surface of the liquid cementitious material concentration device 24. The desulfurization slurry flows into the flow guide cylinder 25 from the top and flows out from the bottom, and the solid-liquid separation is completed at the bottom of the liquid cementitious material concentration device 24, and the final product, i.e., the liquid carbon-negative cementitious material, is obtained by concentration. Obviously, the flow guide cylinder 25 is preferably arranged at the central position of the liquid cementitious material concentration device 24.

[0037] Referring again to Figure 1In a further embodiment of the present application, a fly ash feeding port and a water feeding port are arranged at the top of the fly ash slurry preparation device 4, and a fly ash slurry outlet is arranged at the bottom of the fly ash slurry preparation device 4. The fly ash feeding port is connected to the outlet of the spiral conveying and quantitative feeding device 2, and the fly ash stored in the fly ash hopper 1 is sent into the fly ash slurry preparation device 4 through the spiral conveying and quantitative feeding device 2. The water feeding port is communicated with a water feeding pipe, and obviously, a water meter 3 should be arranged on the water feeding pipe to control the water quantity. The fly ash slurry outlet is communicated with the fly ash wet feeding port 29 through a fly ash slurry conveying pipe 7, and the prepared fly ash slurry is fed into the exchange reaction zone of the fly ash carbon sequestration modification reactor 8.

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

[0039] With reference to the foregoing Figure 1 In a further embodiment of the present application, a water distributor 17, a splash plate 18 and a flue gas diffusion plate 15 are arranged in the absorption tower 20 from top to bottom. The bottom of the absorption tower 20 is in the shape of a funnel, which 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 is connected to the dedusted flue gas, and a plurality of air distribution heads 16 can be arranged on the flue gas diffusion plate 15 to uniformly release the dedusted flue gas. A flue gas induced draft fan 14 is arranged on the dedusted flue gas pipeline to provide power for sending the dedusted flue gas to the flue gas diffusion plate 15. The desulfurization liquid outlet 33 is connected to the water distributor 17 through a desulfurization liquid conveying pipeline, and a desulfurization liquid spraying pump 13 is arranged on the desulfurization liquid conveying pipeline to provide conveying power. The collection tank 22 is connected back to the desulfurization slurry backflow port 31 to realize the backflow of the desulfurization slurry to the fly ash carbon sequestration modification reactor 8. The absorption tower 20 is installed on the base 21, and a demister 23 is arranged inside the absorption tower 20 above the water distributor 17, so as to demist the reacted flue gas and discharge it from the top in an organized manner.

[0040] With reference to the foregoing Figure 1In further embodiments of the present application, a water collecting weir 27 is arranged in the liquid cementitious material concentration device 24, and the water collecting weir 27 is arranged at an upper position. The desulfurization slurry discharged from the desulfurization slurry discharge port 32 enters the flow guide cylinder 25 from the desulfurization slurry pipeline, and a slurry pump two 35 is arranged on the desulfurization slurry pipeline to provide discharge power. The desulfurization slurry flows out from the bottom of the flow guide cylinder 25, is gradually concentrated, and the upward flowing separated water is collected by the water collecting weir 27 and is transported to the fly ash slurry preparation device 4 through the backflow pipeline 19 as water for preparing the fly ash slurry. A backflow pump 28 is arranged on the backflow pipeline 19 to provide backflow power. The concentrated liquid negative carbon cementitious material is discharged from the bottom of the liquid cementitious material concentration device 24, and is collected and used, and the discharge port thereof can be provided with a slurry pump one 26 due to the high concentration.

[0041] According to the above device, the present application provides a preparation method of fly ash wet desulfurization coupled with acid-activated cementitious material by continuous flow, and mainly includes the following steps:

[0042] Step 1, fly ash and water are added 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 introduced into the fly ash carbon sequestration modification reactor 8 through the fly ash wet addition port 29, and a medicament for strengthening carbon dioxide absorption is introduced into the fly ash carbon sequestration modification reactor 8 through the additive addition port. For example, the medicament is an alcohol amine organic substance, which is used to strengthen 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 zone is transported to the absorption tower 20 as desulfurization liquid, and the dedusting flue gas is introduced into the absorption tower 20. In the absorption tower 20, the desulfurization liquid and the dedusting flue gas perform mass transfer and reaction to realize desulfurization and carbon sequestration, and absorb sulfur dioxide to convert into desulfurization slurry. The desulfurization slurry is backflowed to the fly ash carbon sequestration modification reactor 8, a part of which is upwardly mixed with the fly ash slurry under the stirring action, and the other part is directly discharged to the liquid cementitious material concentration device 24 to separate and concentrate, and the slurry with reduced water content is the liquid negative carbon cementitious material.

[0044] Further, when the specific structure of the absorption tower 20 is adopted, the desulfurization and carbon sequestration process in it is as follows: the clear liquid in the clear water area is delivered to the water distributor 17 by the desulfurization liquid spraying pump 13 as the desulfurization liquid at the required flow rate, the dust removal flue gas is delivered to the flue gas diffusion plate 15 and the air distribution head 16 by the flue gas induced draft fan 14, so that the flue gas to be desulfurized is uniformly distributed. The desulfurization liquid is uniformly dispersed by the water distributor 17 and falls to the bottom of the tower, and flows through the three layers of splash plates 18 in turn, and in the process, it is countercurrently contacted with the dust removal flue gas, so that the sulfur dioxide and carbon dioxide in the flue gas are diffused, mass transferred, absorbed and fixed with the desulfurization liquid drops, and the desulfurization and carbon sequestration of the flue gas is realized, the sulfur dioxide and carbon dioxide in the flue gas are removed, and the desulfurized flue gas discharged from the flue gas is discharged in an organized manner after removing water vapor by the demister 23. The desulfurized slurry obtained after absorbing sulfur dioxide finally falls into the collection tank 22, and then is returned to the fly ash carbon sequestration modification reactor 8 through the pipeline. In the exchange reaction area, part of the fly ash slurry is mixed and reacted again with the fly ash slurry under the action of the screw stirrer 10, and the other part of the desulfurized slurry is 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. For example, the effective countercurrent contact time of the dust removal flue gas and the desulfurization liquid is 8-12 s, and the liquid-gas ratio is 6-15 L / m 3 .

[0045] Specifically, in the fly ash carbon sequestration modification reactor 8, the fly ash slurry from the fly ash slurry preparation device 4 is directly mixed with the desulfurized slurry returned from the absorption tower 24 at the bottom. The desulfurized 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 is adsorbed on the surface of the fly ash particles, completing the interphase migration and fixation of carbon dioxide and sulfur dioxide in the desulfurized slurry. At the same time, the unreacted calcium oxide and magnesium oxide in the fly ash slurry are further dissolved in the desulfurized slurry, finally realizing the regeneration of the desulfurization liquid, and realizing the separation of the desulfurization liquid and the fly ash slurry in the process of flowing upward through the gradually expanded solid-liquid separation area. For example, the solid mass concentration of fly ash in the exchange reaction area is 10-20%, and the reaction time is 5-10 min.

[0046] Specifically, in the liquid cementitious material concentration device 24, the desulfurized slurry flows from top to bottom under the action of the draft tube 25, and separates and concentrates under the action of the draft 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 in the slurry concentration process is collected by the water collecting weir 27 at the upper part of the device and is lifted to the fly ash slurry preparation device 4 by the return pump 28. The slurry concentrated to an appropriate water content at the bottom is the finished liquid negative carbon cementitious material, which is delivered to the use point by the slurry pump 26. For example, the downward flow velocity of the desulfurized slurry in the draft tube 25 is 0.2-0.3 m / s, and the surface load is 20-50 m 3 / m 2h, the residence time is 10-30 min, and the solid mass concentration of the final obtained liquid carbon-negative cementitious material is 50-60%.

[0047] Further, the present application is provided with a sludge interface instrument 34 in the fly ash carbon fixation modification reactor 8, which can be installed at the top of the reactor and can monitor the sludge liquid level of the solid-liquid separation zone in real time. When the sludge surface has a rising trend, the discharge amount of the desulfurization slurry to the liquid cementitious material concentration device 24 is increased to control the sludge surface in the fly ash carbon fixation modification reactor 8 to decrease. Specifically, the rotation speed of the screw belt stirrer 10 can be increased, the power of the slurry pump two 35 can be increased, and the like. When the sludge surface has a decreasing trend, the discharge amount of the desulfurization slurry to the liquid cementitious material concentration device 24 is decreased to control the sludge surface in the fly ash carbon fixation modification reactor 8 to increase. Specifically, the rotation speed of the screw belt stirrer 10 can be decreased, the power of the slurry pump two 35 can be decreased, and the like. Thus, the balance between the exchange reaction effect and the cleaning degree of the desulfurization liquid can be achieved.

[0048] In one specific embodiment of the present application, the fly ash carbon fixation modification reactor 8 has a bottom diameter of 8 meters and a height of 10 meters, the clear water area has a diameter of 16 meters and a height of 8 meters, and 210-260 tons of fly ash are consumed per hour. The absorption tower 20 has a diameter of 8 meters and a total height of 35 meters, and 1.3-1.7 x 10 7 m 3 Coal-fired flue gas. The liquid cementitious material concentration device 24 has a diameter of 8 meters and a height of 12 meters, and 400-500 tons of gel materials are produced per hour.

[0049] In this embodiment, the dust removal flue gas from the Fu County power plant and the fly ash of the power plant are used for experiments. The conversion concentration of SO2 in the flue gas before desulfurization is about 1500 mg / m 3 The main components of the fly ash are CaO and SiO2. After the present application, the desulfurized flue gas discharged from the absorption tower is detected, in which the conversion concentration of SO2 is 33 mg / m 3 , less than 35 mg / m 3 , which meets the ultra-clean emission requirements, and the desulfurization efficiency reaches 97.8%. At the same time, the carbon fixation amount of the fly ash slurry is calculated to be about 56.16 kg / t.

[0050] In summary, the present application realizes the integration of fly ash and dust removal flue gas for simultaneous desulfurization and carbon reduction. Fly ash containing free calcium oxide is quantitatively transported to a fly ash slurry preparation device for hydration and slurry preparation by using a precise metering feeding system. Then, the slurry is injected into the absorption tower through a multi-stage mixing intensification system and a pressurized conveying unit in the fly ash carbon fixation modification reactor 8. In the tower, the slurry and the boiler flue gas flowing in the opposite direction realize efficient gas-liquid mass transfer in the stepped multi-hole distribution plate system formed by the splash plate 18, and simultaneously complete SO2 removal and CO2 mineralization and fixation to generate gypsum and calcium carbonate precipitates. The desulfurized slurry after reaction is collected by the bottom collecting tank to strengthen the reaction efficiency, and can be transported to the paste filling station and other places for use after dehydration by the liquid cementitious material concentration device 24, and the overflow liquid is closed-loop returned to the fly ash slurry preparation process. The process innovation realizes the three-dimensional coupling of coal combustion solid waste resource utilization, flue gas multi-pollutant simultaneous treatment and filling material preparation, significantly reduces the marginal cost of solid waste disposal and flue gas purification system, and has the advantages of engineering applicability and environmental economy.

[0051] It should be noted that for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, and any reference signs in the claims should not be considered as limiting the claims involved.

[0052] The above disclosed preferred embodiments of the present application are only used to help explain the present application. The preferred embodiments do not describe all the details and do not limit the present application to specific embodiments. Obviously, many modifications and changes can be made according to the content of the present application. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited only by the claims and their entire scope and equivalents.

Claims

1. A continuous flow fly ash wet desulfurization liquid preparation device, characterized in that, The reactor includes a fly ash carbon fixation and modification reactor (8), which consists of a columnar lower part and a gradually expanding upper part. Its interior is divided into an exchange reaction zone, a solid-liquid separation zone and a clear water zone from bottom to top. The solid-liquid separation zone includes at least a part of the gradually expanding upper part to achieve a gradually expanding flow cross section. The fly ash carbon fixation and modification reactor (8) is equipped with three material inlets and two material outlets. The three material inlets are the fly ash wet dosing port (29) directly connected to the exchange reaction zone, the desulfurization slurry return port (31), and the admixture dosing port (30) directly connected to the solid-liquid separation zone. The two material outlets are the desulfurization liquid outlet (33) directly connected to the clear water zone and the desulfurization slurry discharge port (32) directly connected to the exchange reaction zone. The admixture dosing port (30) is used to add the agent to enhance carbon dioxide absorption. The desulfurization slurry is obtained by the desulfurization liquid absorbing sulfur dioxide outside the fly ash carbon fixation and modification reactor (8). The desulfurization liquid is the supernatant after the fly ash and desulfurization slurry exchange reaction and solid-liquid separation. The wet feed port (29) for fly ash extends into the exchange reaction zone and is at a distance from the bottom surface of the fly ash carbon fixation and modification reactor (8). The desulfurization slurry return port (31) is located below the wet feed port (29) for fly ash. The fly ash carbon fixation and modification reactor (8) has a built-in ribbon agitator (10), which is at least located in the exchange reaction zone. The maximum diameter of the gradually expanding upper part is increased 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 wet fly ash inlet (29) and the bottom surface of the fly ash carbon fixation and modification reactor (8) is equal to 1 / 3 to 1 / 2 of the diameter of the lower part of the column. The additive inlet (30) is located deep in the solid-liquid separation interface of the solid-liquid separation zone.

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

3. A continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation device, characterized in that, 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 a continuous flow fly ash wet desulfurization liquid preparation device as described in claim 1 or 2; The fly ash slurry preparation device (4) is used to prepare fly ash slurry and is connected to the fly ash wet dosing port (29); the admixture dosing device (9) is equipped with an agent to enhance carbon dioxide absorption and is connected to the admixture dosing port (30); the absorption tower (20) is connected to the desulfurization liquid outlet (33) and the desulfurization slurry return port (31) and is used to use the dust removal flue gas to absorb sulfur dioxide in the desulfurization liquid and convert it into desulfurization slurry and return it; the liquid cementitious material concentration device (24) is equipped with a guide tube (25), the top of the guide tube (25) is the inlet and is connected to the desulfurization slurry outlet (32), and the bottom is gradually widening along the flow direction. The desulfurization slurry completes solid-liquid separation at the bottom of the liquid cementitious material concentration device (24) and is concentrated to obtain liquid negative carbon cementitious material.

4. The apparatus for preparing continuous flow fly ash wet desulfurization coupled with acid-activated cementitious materials according to claim 3, characterized in that, The absorption tower (20) is equipped with a water distributor (17), a splash plate (18) and a flue gas diffuser (15) from top to bottom. The bottom of the absorption tower (20) is a collection tank (22). The flue gas diffuser (15) is connected to the dust removal flue gas, the desulfurization liquid outlet (33) is connected to the water distributor (17), and the collection tank (22) is connected to the desulfurization slurry return port (31).

5. The apparatus for preparing continuous flow fly ash wet desulfurization coupled with acid-activated cementitious materials according to claim 3, characterized in that, The liquid cementitious material concentration device (24) is equipped with a water collection weir (27). The separated water is collected through the water collection weir (27) and then transported to the fly ash slurry preparation device (4). The concentrated liquid negative carbon cementitious material is discharged from the bottom.

6. A method for preparing a continuous flow fly ash wet desulfurization coupled acid-activated cementitious material, implemented based on the continuous flow fly ash wet desulfurization coupled acid-activated cementitious material preparation apparatus according to any one of claims 3 to 5, characterized in that, Includes the following steps: Fly ash and water are added to the fly ash slurry preparation device (4) to prepare fly ash slurry, which is then fed into the fly ash carbon fixation and modification reactor (8) through the fly ash wet feeding port (29); and the agent for enhancing carbon dioxide absorption is added. The liquid from the clear water zone is transported to the absorption tower (20) as desulfurization liquid, and dust removal flue gas is introduced into the absorption tower (20). The desulfurization liquid and the dust removal flue gas undergo mass transfer and reaction to achieve desulfurization and carbon fixation, and absorb sulfur dioxide to transform into desulfurization slurry. The desulfurization slurry is returned to the fly ash carbon fixation modification reactor (8). Part of it rises under the action of stirring and mixes with the fly ash slurry again, while the other part is directly discharged to the liquid cementitious material concentration device (24), where separation and concentration occur. The slurry with reduced water content is the liquid negative carbon cementitious material.

7. The method for preparing continuous flow fly ash wet desulfurization coupled with acid-activated cementitious material according to claim 6, characterized in that, The agent for enhancing carbon dioxide absorption is an alcohol amine organic compound, with a dosage of 1-10 mg / L. The solid mass concentration of fly ash in the fly ash slurry is 50-60%, and the solid mass concentration of fly ash in the exchange reaction zone is 10-20%, with a reaction time of 5-10 min. In the absorption tower (20), the effective countercurrent contact time between the dust removal flue gas and the desulfurization liquid is 8-12 s, and the liquid-to-gas ratio is 6-15 L / m³. 3 The downward flow velocity of the guide tube (25) is 0.2~0.3m / s, and the surface load is 20~50m. 3 / m 2 The solid mass concentration of the resulting liquid negative carbon cementitious material is 50-60% after a residence time of 10-30 min.

8. The method for preparing continuous flow fly ash wet desulfurization coupled with acid-activated cementitious material according to claim 7, characterized in that, The fly ash carbon fixation and modification reactor (8) is equipped with a sludge interface meter (34). The sludge interface meter (34) monitors the sludge level in the solid-liquid separation zone in real time. When the sludge level tends to rise, the discharge of desulfurization slurry to the liquid cementitious material concentration device (24) is increased to control the sludge level in the fly ash carbon fixation and modification reactor (8) to drop. When the sludge level tends to drop, the discharge of desulfurization slurry to the liquid cementitious material concentration device (24) is reduced to control the sludge level in the fly ash carbon fixation and modification reactor (8) to rise, so as to balance the exchange reaction effect and the cleanliness of the desulfurization liquid.

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