Flocculation-dehydration-solidification integrated sludge treatment device and method

Abstract

The invention belongs to the technical field of high-water-content sludge resource utilization, and particularly relates to a flocculation-dehydration-solidification integrated sludge treatment device and method.The device comprises a flocculation conditioning assembly used for conducting a flocculation reaction to obtain flocculation conditioning sludge; the mixing and conveying assembly is arranged at the outlet end of the flocculation conditioning assembly; the dewatering and carbon pre-sequestration assembly is arranged at the discharging end of the mixing and conveying assembly, and the dewatering and carbon pre-sequestration assembly is used for receiving the mixed sludge, dewatering the mixed sludge and mixing CO2 foam to obtain a mixed dewatered sludge cake; and the carbon sequestration curing assembly is arranged at the discharging end of the dehydration and carbon sequestration pre-assembly, and the carbon sequestration curing assembly is used for receiving the mixed dehydrated sludge cakes and introducing CO2 to obtain cured sludge. The invention aims to solve the problems of technical flow splitting, easy initiation of alkaline pollution, insufficient mud cake resource utilization and the like, and has the functions of high-water-content sludge chemical flocculation, rapid dehydration, sludge solidification, green carbon sequestration and the like.

Description

Technical Field

[0001] This invention belongs to the field of high water content sludge resource utilization technology, and particularly relates to an integrated sludge treatment device and method for flocculation-dewatering-solidification. Background Technology

[0002] Dredged sludge is widely generated in port and waterway engineering, water conservancy projects, and river dredging. Because dredging operations often employ hydraulic suction, the resulting sludge is characterized by high water content, poor physical and mechanical properties, and high concentration of pollutants, making its treatment extremely difficult. Direct dumping not only wastes land resources but also poses a risk of pollution spread. Existing sludge treatment technologies separate dewatering and solidification processes, resulting in high costs and energy consumption, and the potential for leakage and secondary pollution during transport. These technologies suffer from process fragmentation and insufficient coordination. Furthermore, traditional solidification processes often use cement as a solidifying agent, which generates large amounts of carbon dioxide during production, resulting in highly alkaline solidified soil unsuitable for vegetation growth, thus contradicting environmental protection principles.

[0003] Therefore, it is necessary to design an integrated flocculation-dewatering-solidification sludge treatment device and method to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide an integrated flocculation-dehydration-solidification sludge treatment device and method, which aims to solve problems such as fragmented technical processes, easy alkaline pollution, and insufficient utilization of sludge cake resources. This device has functions such as chemical flocculation, rapid dehydration, sludge solidification, and green carbon fixation for sludge with high water content. It can perform integrated treatment of sludge with high water content throughout the entire process to achieve synergistic benefits of sludge resource utilization and low-carbon environmental protection.

[0005] To achieve the above objectives, the present invention provides the following solution: an integrated flocculation-dewatering-solidification sludge treatment device, comprising: a flocculation conditioning component for performing a flocculation reaction to obtain flocculated and conditioned sludge; a mixing and conveying component disposed at the outlet end of the flocculation conditioning component, wherein the mixing and conveying component is used to receive the flocculated and conditioned sludge and add solidifying material to the flocculated and conditioned sludge to obtain mixed sludge; a dewatering and pre-carbonization component disposed at the discharge end of the mixing and conveying component, wherein the dewatering and pre-carbonization component is used to receive the mixed sludge and dewater it and mix it with CO2 foam to obtain mixed dewatered sludge cake; and a carbonization and solidification component disposed at the discharge end of the dewatering and pre-carbonization component, wherein the carbonization and solidification component is used to receive the mixed dewatered sludge cake and introduce CO2 to obtain solidified sludge.

[0006] According to the present invention, an integrated sludge treatment device for flocculation-dehydration-solidification is provided. The flocculation conditioning component includes a flocculation stirring mechanism. The inlet end of the flocculation stirring mechanism is connected to a sludge conveying mechanism, and the outlet end of the flocculation stirring mechanism is connected to a flocculation conditioning sludge conveying mechanism. The mixing and conveying component is disposed at the outlet end of the flocculation conditioning sludge conveying mechanism, and the top end of the flocculation stirring mechanism is connected to a first flocculant conveying mechanism and a second flocculant conveying mechanism.

[0007] According to the present invention, an integrated flocculation-dehydration-solidification sludge treatment device is provided, wherein the mixing and conveying component includes a first spiral conveying mechanism, the feed end of the first spiral conveying mechanism is correspondingly provided with the outlet end of the flocculation and conditioning sludge conveying mechanism, the feed end of the first spiral conveying mechanism is also correspondingly provided with a solidification material conveying mechanism, and the dehydration and pre-carbonization component is provided at the discharge end of the first spiral conveying mechanism.

[0008] According to the present invention, an integrated sludge treatment device for flocculation-dewatering-solidification is provided. The dewatering and pre-carbonization component includes a screw press. The feed end of the screw press is correspondingly arranged with the discharge end of the first screw conveyor mechanism. The discharge end of the screw press is correspondingly arranged with the feed end of the second screw conveyor mechanism. The feed end of the second screw conveyor mechanism is also correspondingly arranged with a CO2 foam conveying mechanism. The feed end of the carbonization and solidification component is correspondingly arranged with the discharge end of the second screw conveyor mechanism.

[0009] According to the present invention, an integrated sludge treatment device for flocculation-dehydration-solidification is provided, wherein the carbon solidification component includes a layered stockpile, the layered stockpile is correspondingly arranged with the discharge end of the second screw conveyor mechanism, and the layered stockpile is connected to a CO2 conveying mechanism.

[0010] According to the present invention, an integrated flocculation-dehydration-solidification sludge treatment device is provided. The flocculation mixing mechanism includes a flocculation mixing tank. The first flocculant conveying mechanism includes a first flocculant mixing tank and a first pipeline. The second flocculant conveying mechanism includes a first screw feeder and a second pipeline. The sludge conveying mechanism includes a third pipeline. The flocculation-conditioning sludge conveying mechanism includes a fourth pipeline. The third pipeline is connected to the inlet end of the flocculation mixing tank, and the fourth pipeline is connected to the outlet end of the flocculation mixing tank. The first flocculant mixing tank is connected to the flocculation mixing tank through the first pipeline, and the first screw feeder is connected to the flocculation mixing tank through the second pipeline.

[0011] According to the present invention, an integrated flocculation-dewatering-solidification sludge treatment device is provided. The first spiral conveying mechanism includes a first double spiral conveyor, which is provided with a first double spiral conveyor inlet, a second double spiral conveyor inlet, and a first double spiral conveyor outlet. The solidification material conveying mechanism includes a second spiral feeder and a fifth pipe. The first double spiral conveyor inlet is correspondingly provided with the outlet end of the flocculation and conditioning sludge conveying mechanism, the second double spiral conveyor inlet is correspondingly provided with the fifth pipe, and the first double spiral conveyor outlet is correspondingly provided with the inlet end of the screw press.

[0012] According to the present invention, an integrated flocculation-dewatering-solidification sludge treatment device is provided. The screw press includes a screw press inlet and a screw press outlet. The second screw conveyor mechanism includes a second double screw conveyor with a first inlet, a second inlet, and an outlet. The CO2 foam conveying mechanism includes a CO2 foam storage tank and a sixth pipe. The screw press inlet corresponds to the outlet of the first screw conveyor mechanism, the screw press outlet corresponds to the first inlet of the second double screw conveyor, the sixth pipe corresponds to the second inlet of the second double screw conveyor, and the second double screw conveyor outlet corresponds to the stratified storage area.

[0013] According to the present invention, an integrated flocculation-dehydration-solidification sludge treatment device is provided, wherein the CO2 conveying mechanism includes a CO2 storage tank and a CO2 conveying pipeline, and the CO2 conveying pipeline is connected to the stratified stockpile.

[0014] A method for treating sludge using an integrated flocculation-dewatering-solidification sludge treatment device includes the following steps: adding sludge, a first flocculant, and a second flocculant into a flocculation conditioning component to undergo a flocculation reaction, resulting in flocculated and conditioned sludge; the flocculated and conditioned sludge enters a mixing and conveying component, where a solidifying material is simultaneously added to the mixing and conveying component, resulting in mixed sludge; the mixed sludge enters a dewatering and pre-carbonization component for dewatering, where CO2 foam is simultaneously added to the dewatering and pre-carbonization component, resulting in mixed dewatered sludge cake; the mixed dewatered sludge cake enters a carbonization and solidification component, where CO2 is simultaneously added to the carbonization and solidification component, resulting in solidified sludge.

[0015] Compared with existing technologies, this invention has the following advantages and technical effects: 1. The flocculation conditioning component fully mixes the polymeric flocculant and inorganic coagulant aid with the high-moisture sludge, causing a flocculation reaction to obtain flocculated and conditioned sludge, which is then transported to the mixing and conveying component. The addition of the polymeric flocculant acts as a bridge, enabling sludge particles to quickly settle, which helps improve the efficiency of subsequent mud-water separation; the addition of the inorganic coagulant aid plays a role in ion exchange and double-layer compression, making the formed floc structure more compact and further promoting flocculation efficiency; the flocculated and conditioned sludge obtained by thorough stirring can prevent pipe blockage and significantly improve the subsequent dewatering efficiency.

[0016] 2. The mixing and conveying assembly uses an MgO-based solidifying material to uniformly mix with the flocculated and conditioned sludge during the conveying process, resulting in mixed sludge which is then conveyed to the dewatering and pre-carbonization assembly. Using MgO as a base material, and compounded with one or more of blast furnace slag, metakaolin, and fly ash, the solid waste solidifying agent avoids the risk of alkali pollution during the solidification process, does not reduce the flocculation and dewatering effect, and is not only more environmentally friendly than traditional cement solidifying agents but also significantly reduces production costs. The mixing and conveying assembly prevents the solidifying material from agglomerating, ensuring uniform dispersion of the solidifying material in the mixed sludge, which facilitates subsequent thorough carbonization and solidification.

[0017] 3. The mixed sludge is transported to the dewatering and pre-carbonization assembly for rapid dewatering, resulting in a dewatered sludge cake. This cake is then mixed with CO2 foam to obtain a pre-carbonized mixed sludge cake, which is then transported to the carbon fixation and solidification assembly. The highly efficient dewatering of the dewatering and pre-carbonization assembly significantly shortens the dewatering time and improves dewatering efficiency. It also prevents sludge blockage and ensures the continuity of the entire process. Pre-carbonizing the dewatered sludge cake with CO2 foam not only optimizes the cake structure and significantly improves the strength of the subsequently solidified soil, enhancing the resource value of the sludge cake, but also allows for pre-alkali neutralization, avoiding alkali contamination.

[0018] 4. The mixed dewatered sludge cake undergoes a carbon fixation reaction within the carbon fixation and solidification component, which both retains CO2 and produces solidified sludge. The carbon fixation and solidification component increases the contact area between the mixed sludge cake and CO2, making the carbon fixation reaction more complete and improving carbon fixation efficiency. Passing CO2 into the mixed dewatered sludge cake generates crystals with high hardness and stability, such as magnesium carbonate and calcium carbonate, thereby further improving the strength of the solidified sludge. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall invention.

[0021] Figure 2 This is a schematic diagram of the top of the first spiral feeder of the present invention.

[0022] Figure 3 This is a schematic diagram of the bottom of the first spiral feeder of the present invention.

[0023] Figure 4 This is a schematic diagram of the top of the first double-helix conveyor of the present invention.

[0024] Figure 5 This is a schematic diagram of the bottom of the first double-helix conveyor of the present invention.

[0025] Figure 6 This is a schematic diagram of the pipeline used to transport CO2 according to the present invention.

[0026] The components include: 1. Flocculation conditioning component; 2. Mixing and conveying component; 3. Dehydration and pre-carbonization component; 4. Carbonization and solidification component; 11. Flocculation mixing mechanism; 111. Flocculation mixing tank; 12. First flocculant conveying mechanism; 121. First flocculant mixing tank; 122. First pipeline; 13. Second flocculant conveying mechanism; 131. First screw feeder; 1311. Screw shaft of first screw feeder; 132. Feed inlet of first screw conveyor; 133. Discharge outlet of first screw conveyor; 134. Second pipeline; 14. Sludge conveying mechanism; 141. Third pipeline; 15. Flocculation conditioning sludge conveying mechanism; 151. Fourth pipeline; 21. First screw conveying mechanism; 211. First double screw conveyor; 212. First feed inlet of first double screw conveyor; 213. Second feed inlet of first double screw conveyor; 214. 1. First double-helix conveyor outlet; 22. Solidified material conveying mechanism; 221. Second helical feeder; 224. Fifth pipeline; 31. Screw press; 311. Screw press inlet; 312. Screw press outlet; 32. Second helical conveying mechanism; 321. Second double-helix conveyor; 322. First inlet of second double-helix conveyor; 323. Second inlet of second double-helix conveyor; 324. Discharge outlet of second double-helix conveyor; 33. CO2 foam conveying mechanism; 331. CO2 foam storage tank; 332. Sixth pipeline; 41. Layered storage yard; 42. CO2 conveying mechanism; 421. CO2 storage tank; 422. Pipeline for conveying CO2; 4221. Main pipeline; 4222. Porous exhaust pipes for each layer; 42221. Exhaust port; 4223. Main pipeline of porous exhaust pipes for each layer. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figures 1 to 6 As shown, the present invention provides an integrated flocculation-dewatering-solidification sludge treatment device, comprising: a flocculation conditioning component 1, used for performing flocculation reaction to obtain flocculated and conditioned sludge; a mixing and conveying component 2, disposed at the outlet end of the flocculation conditioning component 1, used to receive the flocculated and conditioned sludge and add solidifying material to the flocculated and conditioned sludge to obtain mixed sludge; a dewatering and pre-carbonization component 3, disposed at the discharge end of the mixing and conveying component 2, used to receive the mixed sludge and dewater it and mix it with CO2 foam to obtain mixed dewatered sludge cake; and a carbonization and solidification component 4, disposed at the discharge end of the dewatering and pre-carbonization component 3, used to receive the mixed dewatered sludge cake and introduce CO2 to obtain solidified sludge.

[0030] Furthermore, the flocculation conditioning component 1 includes a flocculation stirring mechanism 11, the inlet end of which is connected to a sludge conveying mechanism 14, the outlet end of which is connected to a flocculation conditioning sludge conveying mechanism 15, the mixing and conveying component 2 is disposed at the outlet end of the flocculation conditioning sludge conveying mechanism 15, and the top end of the flocculation stirring mechanism 11 is connected to a first flocculant conveying mechanism 12 and a second flocculant conveying mechanism 13.

[0031] High-moisture-content dredged sludge is transported to the flocculation and mixing mechanism 11 via the sludge conveying mechanism 14. Simultaneously, the first flocculant is quantitatively transported to the flocculation and mixing mechanism 11 via the first flocculant conveying mechanism 12 and the second flocculant via the second flocculant conveying mechanism 13. The high-moisture-content dredged sludge, the first flocculant, and the second flocculant are stirred and mixed inside the flocculation and mixing mechanism 11 to obtain flocculated and conditioned sludge. The first flocculant is a polymeric flocculant that can make sludge particles settle quickly, while the second flocculant is an inorganic flocculant that can make the formed floc structure more compact. The addition of the two flocculants can improve the flocculation efficiency and significantly improve the dewatering efficiency of the subsequent dewatering mechanism.

[0032] Furthermore, the mixing and conveying assembly 2 includes a first spiral conveying mechanism 21, the feed end of the first spiral conveying mechanism 21 is correspondingly set with the outlet end of the flocculation and conditioning sludge conveying mechanism 15, the feed end of the first spiral conveying mechanism 21 is also correspondingly set with a solidification material conveying mechanism 22, and the dewatering and pre-carbonizing assembly 3 is set at the discharge end of the first spiral conveying mechanism 21.

[0033] Flocculated and conditioned sludge is conveyed to the first spiral conveyor 21 via the flocculated and conditioned sludge conveying mechanism 15. Simultaneously, MgO-based solidification material is conveyed to the first spiral conveyor 21 via the solidification material conveying mechanism 22. The first spiral conveyor 21 conveys and mixes the material to the next component while simultaneously agitating it to obtain mixed sludge. The MgO-based solidification material avoids the risk of alkali contamination during the solidification process and is not only more environmentally friendly but also less expensive than traditional solidification agents. The twin spiral conveyor prevents the solidification material from agglomerating, which is beneficial for subsequent carbon fixation and solidification, and also ensures the continuity of the entire process.

[0034] Furthermore, the dehydration and pre-carbonization component 3 includes a screw press 31, the feed end of which is correspondingly set to the discharge end of the first screw conveyor 21, the discharge end of which is correspondingly set to the feed end of the second screw conveyor 32, the feed end of which is also correspondingly set to the CO2 foam conveying mechanism 33, and the feed end of the carbonization and solidification component 4 is correspondingly set to the discharge end of the second screw conveyor 32.

[0035] The mixed sludge is conveyed to the inlet of the screw press 31 via the first screw conveyor 21, where it undergoes rapid dewatering to obtain a dewatered cake. This dewatered cake is then conveyed through the screw press 31 to the second screw conveyor 32. Simultaneously, CO2 foam is conveyed to the second screw conveyor 32 via the CO2 foam conveyor 33. The second screw conveyor 32 simultaneously stirs and conveys the sludge, resulting in a dewatered cake mixed with CO2 foam. The screw press's high-efficiency dewatering significantly improves dewatering efficiency, prevents sludge blockage, and ensures process continuity. Mixing CO2 foam into the dewatered cake not only improves curing efficiency and strength but also allows for pre-neutralization with alkali, preventing alkali contamination.

[0036] Furthermore, the carbon solidification component 4 includes a layered storage area 41, which is correspondingly arranged with the discharge end of the second spiral conveyor mechanism 32, and the layered storage area 41 is connected to the CO2 conveyor mechanism 42.

[0037] The mixed dewatered sludge cake is conveyed to the stratified storage area 41 via the second spiral conveyor mechanism 32. Simultaneously, CO2 is conveyed between the layers of the stratified storage area 41 via a CO2 conveying mechanism. Multiple porous exhaust pipes are arranged between the layers of the stratified storage area 41 for uniform CO2 delivery. The stratified stacking method increases the contact area between the sludge cake and CO2, improving carbon fixation efficiency. The introduction of CO2 between the layers can generate crystals with higher hardness, rapidly increasing the strength of the solidified sludge.

[0038] Furthermore, the flocculation mixing mechanism 11 includes a flocculation mixing tank 111, the first flocculant conveying mechanism 12 includes a first flocculant mixing tank 121 and a first pipe 122, the second flocculant conveying mechanism 13 includes a first screw feeder 131 and a second pipe 134, the sludge conveying mechanism 14 includes a third pipe 141, and the flocculation conditioning sludge conveying mechanism 15 includes a fourth pipe 151. The third pipe 141 is connected to the feed end of the flocculation mixing tank 111, and the fourth pipe 151 is connected to the discharge end of the flocculation mixing tank 111. The first flocculant mixing tank 121 is connected to the flocculation mixing tank 111 through the first pipe 122, and the first screw feeder 131 is connected to the flocculation mixing tank 111 through the second pipe 134.

[0039] The first screw feeder 131 has a first screw conveyor inlet 132 at its upper end; the first screw feeder 131 has a first screw conveyor outlet 133 at its lower end, and a second pipe 134 for conveying the second flocculant is provided at the first screw conveyor outlet 133; the first screw feeder screw shaft 1311 of the first screw feeder 131 is located at the central axis position; the first screw conveyor inlet 132 is funnel-shaped and located at the front section, with the large opening being the feed end; the first screw conveyor outlet 133 is funnel-shaped and located at the rear section, with the large opening being the feed end.

[0040] Furthermore, the first spiral conveying mechanism 21 includes a first double spiral conveyor 211, which is provided with a first double spiral conveyor inlet 212, a second double spiral conveyor inlet 213, and a first double spiral conveyor outlet 214. The solidified material conveying mechanism 22 includes a second spiral feeder 221 and a fifth pipe 224. The first double spiral conveyor inlet 212 is correspondingly provided with the outlet end of the flocculation and conditioning sludge conveying mechanism 15, the second double spiral conveyor inlet 213 is correspondingly provided with the fifth pipe 224, and the first double spiral conveyor outlet 214 is correspondingly provided with the feed end of the screw press 31.

[0041] The first twin-helix conveyor 211 is placed at an angle. The first feed inlet 212 of the first twin-helix conveyor is located below the fourth pipe 151, and the second feed inlet 213 of the first twin-helix conveyor is located below the fifth pipe 224. The first feed inlet 212 of the first twin-helix conveyor is funnel-shaped, with the larger opening being the feed end. The second feed inlet 213 of the first twin-helix conveyor is slightly smaller than the first feed inlet 212 of the first twin-helix conveyor, and is also funnel-shaped, with the larger opening being the feed end. The discharge outlet 214 of the first twin-helix conveyor is funnel-shaped, with the larger opening being the feed end.

[0042] Furthermore, the screw press 31 includes a screw press inlet 311 and a screw press outlet 312. The second spiral conveyor mechanism 32 includes a second double spiral conveyor 321, which is provided with a second double spiral conveyor first inlet 322, a second double spiral conveyor second inlet 323, and a second double spiral conveyor outlet 324. The CO2 foam conveying mechanism 33 includes a CO2 foam storage tank 331 and a sixth pipe 332. The screw press inlet 311 is corresponding to the outlet end of the first spiral conveyor mechanism 21, the screw press outlet 312 is corresponding to the first inlet 322 of the second double spiral conveyor, the sixth pipe 332 is corresponding to the second inlet 323 of the second double spiral conveyor, and the second double spiral conveyor outlet 324 is corresponding to the layered storage yard 41.

[0043] CO2 foam is prepared using a low-pressure foam generator with "water-based + trace amount of environmentally friendly foaming agent"; the bubble diameter is controlled at 50-200μm and does not collapse for 3-5 minutes when left to stand.

[0044] The feed inlet 311 of the screw press is funnel-shaped, with the large opening being the feed end, located below the discharge outlet 214 of the first double screw conveyor; the discharge end is bucket-shaped.

[0045] The first feed inlet 322 of the second twin-helix conveyor is located below the discharge outlet 312 of the screw press, and the second feed inlet 323 of the second twin-helix conveyor is located below the sixth pipe 332.

[0046] Furthermore, the CO2 conveying mechanism 42 includes a CO2 storage tank 421 and a CO2 conveying pipe 422, which is connected to the stratified storage yard 41.

[0047] The CO2 transport pipeline 422 includes a main pipeline 4221, multi-layer perforated exhaust pipelines 4222, and a main pipeline 4223 for multi-layer perforated exhaust pipelines.

[0048] The single-layer height of the stratified storage yard 41 is 30-50cm.

[0049] The bottom of the CO2 storage tank 421 is connected to the main pipeline 4221; the main pipeline 4223 of each layer of porous exhaust pipeline is connected to the pipeline 422 for conveying CO2; the porous exhaust pipeline 4222 of each layer is located between each layer of the layered storage yard 41, and the porous exhaust pipeline 4222 of each layer is connected to the main pipeline 4223 of the porous exhaust pipeline of each layer; each layer of porous exhaust pipeline 4222 is provided with multiple exhaust holes 42221, each exhaust hole 42221 is spaced 2-3cm apart and is evenly distributed, and the porous exhaust pipeline 4222 of each layer is spaced 5-10cm apart and is evenly distributed.

[0050] A method for treating sludge using an integrated flocculation-dewatering-solidification sludge treatment device includes the following steps: adding sludge, a first flocculant, and a second flocculant into a flocculation conditioning component 1 to undergo a flocculation reaction, resulting in flocculated and conditioned sludge; the flocculated and conditioned sludge enters a mixing and conveying component 2, while simultaneously adding a solidifying material to the mixing and conveying component 2, resulting in mixed sludge; the mixed sludge enters a dewatering and pre-carbonization component 3 for dewatering, while simultaneously adding CO2 foam to the dewatering and pre-carbonization component 3, resulting in mixed dewatered sludge cake; the mixed dewatered sludge cake enters a carbonization and solidification component 4, while simultaneously adding CO2 to the carbonization and solidification component 4, resulting in solidified sludge.

[0051] Example: River silt with an initial moisture content of 380% was used as the experimental mud. APAM flocculant powder was first diluted with water and stirred to prepare a first flocculant solution with a mass fraction of 0.3%. After adding 200 ml of the first flocculant solution and 0.5 g of quicklime powder per liter of sludge, stir for 10 min and let stand for 5 min to obtain flocculated and conditioned sludge. Add the flocculation conditioning solution to the prepared solidification material at a dosage of 100 kg / m³ of solidifying agent, stir for 10 min, and let stand for 5 min to obtain mixed sludge. The proportions of the solidification material are shown in Table 1. The mixed sludge is dehydrated by pressure filtration to obtain dehydrated sludge cake, which is then made into cylindrical specimens with a diameter of 50 mm and a height of 100 mm. If CO2 is introduced, the specimen is placed in a container filled with CO2 gas and cured to the corresponding age. If CO2 is not introduced, the specimen is placed in a standard curing chamber (temperature 20±1℃, relative humidity ≥95%) and cured to the corresponding age. After curing, the compressive strength of the specimen is determined according to GB / T 50123-2019 "Standard for Geotechnical Testing Methods", and the pH value of the specimen is tested at 28 days of curing. The test results are shown in Table 2.

[0052] Table 1 Table 2 As shown in Table 2, Groups 4, 6, and 7 have good curing effects. Their unconfined compressive strength at 7 days all exceeded 0.6 MPa, and their unconfined compressive strength at 28 days all exceeded 1.2 MPa. In addition, the alkali content is low, and the pH value does not exceed 8.0.

[0053] Comparing the data from Group 1 and Group 3, it can be seen that when cement is used as the curing agent, although the strength is slightly higher than that of the composite curing agent, the pH value at 28 days is higher, which may cause alkaline pollution and is not suitable for vegetation growth.

[0054] Comparing the data from Group 1 and Group 2, it can be seen that introducing CO2 into the sample using only cement as a curing agent will reduce the unconfined compressive strength at 7 days and 28 days. This is because the continuous introduction of CO2 will cause carbonization reaction with the hydration products of cement, leading to the destruction of the structure of the hydration products and thus the decrease in strength.

[0055] Comparing the data from Group 3 and Group 4, it can be seen that when CO2 gas was introduced into the samples, the unconfined compressive strength of the samples at 7 days and 28 days was significantly improved, by 124.45% and 101.42% respectively. This proves that introducing CO2 into the dewatered cake can effectively improve the curing effect. As for the pH value at 28 days, Group 4 was 1.8 lower than Group 3, which proves that introducing CO2 into the dewatered cake can also effectively reduce the pH value and reduce the risk of alkali contamination.

[0056] Comparing the data from groups 4 and 5, it can be seen that if only MgO is used as the curing agent, the unconfined compressive strength of the samples at 7 days and 28 days is only 0.286 MPa and 0.495 MPa, respectively, which is 150.35% and 186.06% lower than the strength of the samples with the composite curing agent. This proves that the curing effect of using MgO alone as the curing agent is far inferior to that of the composite curing agent. As for the pH value at 28 days, the pH value of group 4 is 0.8 lower than that of group 5, which proves that the composite curing agent can also effectively reduce the risk of alkali contamination.

[0057] Comparing the data from groups 4, 6, and 7, it can be seen that as the MgO content increases, the pH value at 28 days also increases slightly, and the unconfined compressive strength at 7 days also increases. However, the unconfined compressive strength at 28 days when the MgO content is 60% is slightly higher than that when the MgO content is 70%. This proves that the MgO content in the compound curing agent should be selected according to the requirements of the project. However, in the process of compound application, it is necessary to meet both the alkalinity requirements and the strength requirements.

[0058] As can be seen from the above, in the flocculation conditioning component of this invention, polymeric flocculants and inorganic flocculants work synergistically. The polymeric flocculants can enable sludge particles to quickly form and settle, while the inorganic flocculants can enhance the density and rigidity of the floc structure. The flocs formed by the combination are well-suited for subsequent dewatering processes. The polymeric flocculants are easily degraded when exposed to high salt, while the inorganic flocculants are difficult to agglomerate when exposed to organic matter. The combination of the two is suitable for sludge with high organic matter, salt, and pollutant content. The addition of polymeric flocculants and inorganic flocculants will not affect the subsequent solidification reaction.

[0059] In this invention, the solidification material used in the mixing and conveying assembly is a solidification agent based on MgO and compounded with one or more of blast furnace slag, metakaolin, and fly ash. Compared with traditional solidification agents, this composite solidification agent is less alkaline, thus avoiding soil alkali pollution and significantly reducing corrosion of pipes and interfaces in the device. Traditional solidification agents often use cement, which is not only expensive but also generates a large amount of CO2 during production, making it environmentally unfriendly. In contrast, the compound solidification agent often uses industrial waste, reducing costs while meeting green and low-carbon requirements. Cement as a solidification agent may cause alkali pollution during the solidification of sludge, making it difficult to support vegetation growth. The solidification agent used in this invention can synergistically solidify and restore the ecosystem.

[0060] This invention significantly improves carbon fixation efficiency and shortens the carbon fixation cycle by pre-mixing CO2 foam into the dehydrated mud cake within the dewatering pre-carbonization component. Single-phase gaseous CO2 can only contact the surface layer of the mixed mud cake, resulting in insufficient contact with the inner layer. The stable CO2 foam structure increases the contact time and area between CO2 and the various components in the mixed mud cake, thereby improving pre-carbon fixation efficiency. Traditional solidification measures do not involve a pre-carbonization stage, leading to insufficient strength of the final solidified soil, requiring only simple treatments such as burial. The addition of this stage significantly improves the early strength of the mud cake, accelerates the subsequent solidification reaction, and enables the resource utilization of the mud cake. CO2 foam generates numerous uniform micropores in the mixed mud cake, facilitating the penetration of CO2 gas in the subsequent solidification stage.

[0061] In this invention, the layered stacking of the carbon fixation and solidification component allows for more uniform and thorough mixing of the mixed mud cake with CO2 compared to traditional stacking methods, greatly improving carbon fixation efficiency. Introducing CO2 into the mixed mud cake further enhances the solidification effect, rapidly solidifies the mud cake, and enables the resource utilization of sludge. CO2 can neutralize the alkali in the mud cake, further preventing alkali pollution, thus perfectly combining environmental and engineering benefits.

[0062] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0063] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope of the present invention.

Claims

1. An integrated flocculation-dewatering-solidification sludge treatment device, characterized in that, include: Flocculation conditioning component (1) is used to carry out flocculation reaction to obtain flocculated and conditioned sludge; A mixing and conveying assembly (2) is provided at the outlet end of the flocculation conditioning assembly (1). The mixing and conveying assembly (2) is used to receive flocculated and conditioned sludge and add solidifying material to the flocculated and conditioned sludge to obtain mixed sludge. A dewatering pre-carbon fixation component (3) is provided at the discharge end of the mixing and conveying component (2). The dewatering pre-carbon fixation component (3) is used to receive mixed sludge and dewater and mix it with CO2 foam to obtain mixed dewatered sludge cake. Carbon solidification component (4) is disposed at the discharge end of the dewatering pre-carbon solidification component (3). The carbon solidification component (4) is used to receive the mixed dewatering cake and introduce CO2 to obtain solidified sludge.

2. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 1, characterized in that, The flocculation conditioning component (1) includes a flocculation stirring mechanism (11), the inlet end of which is connected to a sludge conveying mechanism (14), the outlet end of which is connected to a flocculation conditioning sludge conveying mechanism (15), the mixing and conveying component (2) is located at the outlet end of the flocculation conditioning sludge conveying mechanism (15), and the top end of the flocculation stirring mechanism (11) is connected to a first flocculant conveying mechanism (12) and a second flocculant conveying mechanism (13).

3. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 2, characterized in that, The mixing and conveying assembly (2) includes a first spiral conveying mechanism (21), the feed end of the first spiral conveying mechanism (21) is correspondingly provided with the outlet end of the flocculation and conditioning sludge conveying mechanism (15), the feed end of the first spiral conveying mechanism (21) is also correspondingly provided with a solidification material conveying mechanism (22), and the dehydration and pre-carbonization assembly (3) is provided at the discharge end of the first spiral conveying mechanism (21).

4. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 3, characterized in that, The dehydration and pre-carbonization component (3) includes a screw press (31), the feed end of the screw press (31) is correspondingly set to the discharge end of the first screw conveyor (21), the discharge end of the screw press (31) is correspondingly set to the feed end of the second screw conveyor (32), the feed end of the second screw conveyor (32) is also correspondingly set to the CO2 foam conveyor (33), and the feed end of the carbon solidification component (4) is correspondingly set to the discharge end of the second screw conveyor (32).

5. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 4, characterized in that, The carbon solidification component (4) includes a layered storage area (41), which is correspondingly arranged with the discharge end of the second spiral conveyor (32), and the layered storage area (41) is connected to the CO2 conveyor (42).

6. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 2, characterized in that, The flocculation mixing mechanism (11) includes a flocculation mixing tank (111), the first flocculant conveying mechanism (12) includes a first flocculant mixing tank (121) and a first pipe (122), the second flocculant conveying mechanism (13) includes a first screw feeder (131) and a second pipe (134), the sludge conveying mechanism (14) includes a third pipe (141), and the flocculation conditioning sludge conveying mechanism (15) includes a fourth pipe (151). The third pipe (141) is connected to the feed end of the flocculation mixing tank (111), and the fourth pipe (151) is connected to the discharge end of the flocculation mixing tank (111). The first flocculant mixing tank (121) is connected to the flocculation mixing tank (111) through the first pipe (122), and the first screw feeder (131) is connected to the flocculation mixing tank (111) through the second pipe (134).

7. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 4, characterized in that, The first spiral conveying mechanism (21) includes a first double spiral conveyor (211), which is provided with a first double spiral conveyor inlet (212), a second double spiral conveyor inlet (213), and a first double spiral conveyor outlet (214). The solidified material conveying mechanism (22) includes a second spiral feeder (221) and a fifth pipe (224). The first double spiral conveyor inlet (212) is correspondingly provided with the outlet end of the flocculation conditioning sludge conveying mechanism (15), the second double spiral conveyor inlet (213) is correspondingly provided with the fifth pipe (224), and the first double spiral conveyor outlet (214) is correspondingly provided with the feed end of the screw press (31).

8. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 5, characterized in that, The screw press (31) includes a screw press inlet (311) and a screw press outlet (312). The second screw conveyor (32) includes a second double screw conveyor (321). The second double screw conveyor (321) is provided with a second double screw conveyor first inlet (322), a second double screw conveyor second inlet (323), and a second double screw conveyor outlet (324). The CO2 foam conveying mechanism (33) includes a CO2 foam storage tank (331) and a sixth pipe (332). The screw press inlet (311) is corresponding to the outlet end of the first screw conveyor (21). The screw press outlet (312) is corresponding to the first inlet (322) of the second double screw conveyor. The sixth pipe (332) is corresponding to the second inlet (323) of the second double screw conveyor. The second double screw conveyor outlet (324) is corresponding to the layered storage yard (41).

9. The integrated flocculation-dewatering-solidification sludge treatment device according to claim 5, characterized in that, The CO2 conveying mechanism (42) includes a CO2 storage tank (421) and a CO2 conveying pipeline (422), which is connected to the stratified storage yard (41).

10. A method for treating sludge by integrating flocculation, dewatering, and solidification, using the integrated flocculation, dewatering, and solidification sludge treatment device according to any one of claims 1-9, characterized in that, Includes the following steps: Sludge, first flocculant, and second flocculant are added into flocculation conditioning component (1) to carry out flocculation reaction and obtain flocculated conditioning sludge; The flocculated and conditioned sludge enters the mixing and conveying component (2), and at the same time, solidification material is added to the mixing and conveying component (2) to obtain mixed sludge; The mixed sludge enters the dewatering pre-carbonization component (3) for dewatering, and CO2 foam is added to the dewatering pre-carbonization component (3) to obtain mixed dewatered sludge cake; The mixed dewatering cake is fed into the carbon solidification component (4), and CO2 is added into the carbon solidification component (4) to obtain solidified sludge.

Images