A circulating gradient fly ash washing system and method

Abstract

An embodiment of the present invention discloses a circulating gradient fly ash water washing system, which includes a fresh water tank and a premixing tank. The premixing tank is connected to a first beating tank, and the fresh water tank is connected to a second beating tank. The liquid outlet end of the first beating tank is connected to a first pressure filtration device. The first pressure filtration device includes a plurality of filtrate outlets and a filter cake outlet. The plurality of filtrate outlets are respectively connected to corresponding liquid storage devices. The outlet of the liquid storage device is connected to a water treatment system. The filter cake outlet is connected to the second beating tank. The outlet of the second beating tank is connected to a second pressure filtration device. The filter cake outlet of the second pressure filtration device is connected to a drying system. Through the effective cooperation between the equipment systems, after repeated water washing processes, the salts in the fly ash are thoroughly washed. The filtrates with different concentrations after single water washing are respectively retained, and circular water washing is carried out. Finally, a salt solution with a certain concentration that can be recycled is obtained for separation and extraction.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of fly ash treatment and separation, and in particular to a circulating gradient fly ash water washing system and method. Background Art

[0002] Incineration fly ash is generated during the incineration of municipal domestic waste. During the incineration of waste, the organic matter in the waste is mainly discharged in the form of gaseous substances; while the inorganic matter mainly forms solid particles. Among them, the larger solid particles are deposited at the bottom of the incinerator and on the grate, which is called bottom ash, and those fine particles float in the flue gas and enter the flue gas purification system together with the flue gas. These particles account for 50% of the incineration fly ash. The remaining incineration fly ash comes from the limestone or activated carbon added during the flue gas purification process. They are jointly captured in the dust collector (electrostatic precipitator, bag filter, etc.), and at the same time, some fine particles settle at the bottom of the flue and chimney. The fly ash contains a large amount of toxic, harmful and reusable industrial raw materials. Direct discharge will cause environmental pollution and waste of energy.

[0003] In the existing fly ash treatment methods, the water washing system uses a stirring tank + a horizontal screw centrifuge to realize the two functions of water washing and separation. The disadvantages are large floor area, large installed power, high operating cost, many auxiliary equipment and high investment cost. Summary of the Invention

[0004] Therefore, the embodiments of the present invention provide a circulating gradient fly ash water washing system and method to solve the problems in the prior art, such as long overall process, long time, high operating cost, and high solid content in the filtrate, which requires passing through a sand filter and a precision filter to meet the evaporation inlet water quality requirements due to incomplete water washing filtration and difficult recycling of the returned water.

[0005] In order to achieve the above object, the following technical solutions are provided in the embodiments of the present invention:

[0006] In the first aspect of the embodiments of the present invention, a circulating gradient fly ash water washing system is provided, including a fresh water tank and a premixing tank. The premixing tank is connected to a first beating tank. The liquid outlet end of the first beating tank is connected to a first pressure filtering device. The first pressure filtering device includes a plurality of filtrate outlets and a filter cake outlet. The plurality of filtrate outlets are respectively connected to corresponding liquid storage devices. The outlet of the liquid storage device is connected to the first pressure filtering device, a water treatment system, and the premixing tank through a circulating device. The filter cake outlet of the first pressure filtering device is connected to a second beating tank. The outlet of the second beating tank is connected to a second pressure filtering device. The second pressure filtering device includes a filtrate outlet and a filter cake outlet. The filtrate outlet is connected to a corresponding liquid storage device. The outlet of the filtrate tank is connected to the first pressure filtering device through a circulating device. The filter cake outlet is connected to a drying system;

[0007] The liquid storage device includes a pretreatment filtrate tank, a primary water washing filtrate tank, a secondary water washing filtrate tank, and a tertiary water washing filtrate tank. The pretreatment filtrate tank, the primary water washing filtrate tank, the secondary water washing filtrate tank, and the tertiary water washing filtrate tank are respectively connected to a filtrate pump, a first water washing pump, a second water washing pump, and a third water washing pump. The filtrate pump is connected to the water treatment system. The first water washing pump, the second water washing pump, and the third water washing pump are all connected to the liquid inlet end of the first pressure filtration device;

[0008] Separate control valves are provided at the multiple filtrate outlets of the first pressure filtration device, and the control valves are independent of each other.

[0009] Further, the liquid outlet end of the first pressure filtration device is also connected to a lime slaking water tank. The lime slaking water tank is also connected to a premixing tank through a lime slaking water pump, and the premixing tank is connected to the first beating tank.

[0010] Further, the clean water tank is also connected to a second beating tank through a clean water pump, and the second beating tank and the second pressure filtration device are connected through a second beating pump.

[0011] Further, the filtrate outlet of the second pressure filtration device is also connected to a quaternary water washing filtrate tank, and the quaternary water washing filtrate tank is connected to the liquid inlet end of the first pressure filtration device through a fourth water washing pump.

[0012] Further, both the first pressure filtration device and the second pressure filtration device include a base. Two groups of support bodies are correspondingly arranged on the base. A top frame is installed on the upper part of the support body. A pressure filtration assembly driven by a hydraulic device is arranged on the support body. The front and rear sides of the pressure filtration assembly are provided with a feed end, a water inlet end, and a filtrate outlet. The left and right sides of the pressure filtration assembly are provided with the filter cake outlets.

[0013] Further, the pressure filtration assembly is composed of multiple plate-frame groups. The sides between the multiple plate-frame groups are connected by link rods. A driving rod connected to the hydraulic device is provided at the bottom of the plate-frame group;

[0014] The plate-frame group includes a top pressing plate and a bottom pressing plate. Filter cavities are provided on the relative inner sides of the top pressing plate and the bottom pressing plate. A filter plate is provided between the top pressing plate and the bottom pressing plate. A drawable filter cloth is provided on the filter plate. A liquid inlet communicating with the inner filter cavity is provided on one side of the top pressing plate. A liquid outlet communicating with the inner filter cavity is provided on one side of the bottom pressing plate. The filter plate is embedded in the bottom pressing plate, so that the contact surface between the bottom pressing plate and the filter cloth is a plane.

[0015] Further, an isolation membrane is also provided in the filter cavity of the top pressing plate. An extrusion chamber is formed between the isolation membrane and the filter cloth. A pressure chamber is formed between the isolation membrane and the inner wall of the top pressing plate. The liquid inlet is communicated with the extrusion chamber. A pressurizing port communicated with the pressure chamber is also provided on the side of the top pressing plate;

[0016] A distribution pipe interface communicating with the extrusion chamber is further provided on the side surface of the top pressing plate.

[0017] Further, a filter cloth traction mechanism is provided on the base. The filter cloth traction mechanism includes a driving roller and a pressing roller. The filter cloth is arranged between the driving roller and the pressing roller. A rotating shaft is provided at the front and rear ends of two adjacent sets of plate frame groups, and the rotating shaft is arranged at both ends in the pulling direction of the filter cloth. The filter cloth is laid on the rotating shaft and forms a circulating closed structure.

[0018] Further, a displacement sensor and an adjusting wheel are provided at the end of the pressing roller. Columns are also provided on the base. Pulleys are provided on both the upper and lower sides of the columns. A dragging device is provided on the base. The connecting rod in the dragging device is connected to the adjusting wheel through the pulley.

[0019] A fly ash washing and filtering method includes the following operating steps:

[0020] Ⅰ. Primary washing of fly ash

[0021] Put a certain volume of ash slurry in the premixing tank into the first beating tank through an electric valve. The first beating tank is injected into the first pressure filtering device through a beating pump 1. The first pressure filtering device is tightly closed. At the same time, open the control valve connecting to the pretreatment filtrate tank, and the filtrate enters the pretreatment filtrate tank and is stored. The filter cake remains in the filter chamber.

[0022] Inject the clear water in the clear water tank into the pressure filtering device through a clear water pump. At the same time, open the control valve connecting to the first-stage washing filtrate tank, and the filtrate enters the first-stage washing filtrate tank and is stored. The filter cake remains in the filter chamber.

[0023] Inject the clear water in the clear water tank into the pressure filtering device again, so that the filter cake is rinsed with clear water. The pressure filtering device is tightly closed. At the same time, open the control valve connecting to the second-stage washing filtrate tank, and the filtrate enters the second-stage washing filtrate tank and is stored. The filter cake remains in the filter chamber.

[0024] Inject the clear water in the clear water tank into the pressure filtering device again, so that the filter cake is rinsed with clear water. The pressure filtering device is tightly closed. At the same time, open the control valve connecting to the third-stage washing filtrate tank, and the filtrate enters the third-stage washing filtrate tank and is stored. The filter cake is sent to the second beating tank.

[0025] Inject the clear water in the clear water tank into the second beating tank, stir for 30 minutes, and send it to the second pressure filtering device through a second beating pump. The second pressure filtering device is tightly closed. At the same time, open the control valve connecting to the fourth-stage washing filtrate tank, and the filtrate enters the fourth-stage washing filtrate tank and is stored. The filter cake remains in the filter chamber.

[0026] At this time, the salt content concentration of the filter cake is the lowest and can reach the reuse standard, and the filter cake is discharged.

[0027] Ⅱ. Circulating washing

[0028] The filtrate in the primary water-washing filtrate tank is introduced into the ash-dissolving water tank through the first water-washing pump, and is mixed evenly with dry ash to form ash slurry. The ash slurry enters the pressure filtration equipment through the beating pump, and the filtrate enters the pre-treatment filtrate tank. Then, the filtrate in the secondary water-washing filtrate tank enters the pressure filtration equipment through the second water-washing pump, and the control valve connecting to the primary water-washing filtrate tank is opened, and the filtrate enters the primary water-washing filtrate tank; then, the filtrate in the tertiary water-washing filtrate tank is sent to the pressure filtration equipment through the third water-washing pump, and the control valve connecting to the secondary water-washing filtrate tank is opened, and the filtrate enters the secondary water-washing tank; then, the filtrate in the quaternary water-washing filtrate tank is sent to the pressure filtration equipment through the fourth water-washing pump, and the control valve connecting to the tertiary water-washing filtrate tank is opened, and the filtrate enters the tertiary water-washing tank; then, the filter cake is sent into the second beating tank, the clear water in the clear water tank is sent into the second beating tank through the clear water pump, stirred for 30 minutes, sent to the second pressure filtration equipment through the second beating pump, and the control valve connecting to the quaternary water-washing filtrate tank is opened, and the filtrate enters the quaternary water-washing filtrate tank, and the filter cake is sent to the drying system;

[0029] Among them, the working process of the first pressure filtration equipment is as follows: the ash slurry is injected into the pressure filtration equipment, the filtrate is discharged from the filtrate outlet through the filter cloth, and the filter cake remains in the filter cavity for rinsing;

[0030] After the filter cake after repeated rinsing meets the standard, high-pressure water is pumped into the pressure chamber through the pressure inlet. Under the action of the high-pressure water, the isolation membrane approaches the filter plate, forcing the filter cake in the extrusion chamber to drain the water and form lumps, and the high-pressure water is stopped;

[0031] Air is blown into the extrusion chamber through the distribution pipe, the air bulges the isolation membrane and discharges all the high-pressure water. At the same time, through air exchange, the remaining water is discharged through the drain port, and the filter cake is further dried;

[0032] Among them, the working process of the second pressure filtration equipment is as follows: the ash slurry is injected into the pressure filtration equipment, the filtrate is discharged from the filtrate outlet through the filter cloth, and the filter cake remains in the filter cavity;

[0033] High-pressure water is pumped into the pressure chamber through the pressure inlet. Under the action of the high-pressure water, the isolation membrane approaches the filter plate, forcing the filter cake in the extrusion chamber to drain the water and form lumps, and the high-pressure water is stopped;

[0034] Air is blown into the extrusion chamber through the distribution pipe, the air bulges the isolation membrane and discharges all the high-pressure water. At the same time, through air exchange, the remaining water is discharged through the drain port, and the filter cake is further dried;

[0035] Start the hydraulic device, the driving rod opens the top pressure plate and the bottom pressure plate of the plate-frame group, start the driving roller, and the filter cloth runs in a cycle, and the filter cake is discharged from both ends of the filter cloth plate-frame group.

[0036] According to an embodiment of the present invention, the circulating gradient fly ash washing system and method of the present invention have the following advantages:

[0037] 1. Through the effective cooperation between equipment systems, after repeated washing processes, the salts in the fly ash are thoroughly washed. The filtrates with different concentrations after single washing are respectively retained, and washed cyclically. Finally, a salt solution with a certain concentration that can be recycled again is obtained for separation and extraction;

[0038] 2. During the fly ash washing process, through the cooperation between the filter press equipment components, not only can the salts in the washed filter cake be cleaned, but also the filter cake can be fully dried and extruded into shape, which is convenient for later transportation, collection, and reuse;

[0039] 3. For the washing and filtering method of the present invention, first, the fly ash is diluted for the initial cycle. During the washing process, through the automatic control elements, effectively according to the concentration of the filtrate, timely control of how many washing procedures the filtrate needs to go through can more precisely and effectively increase the reuse concentration value of the filtrate, avoiding the possibility that the high-concentration filtrate is recycled again and the filter cake cannot be cleaned, as well as the non-compliance of the low-concentration filtrate, and improving the washing work efficiency;

[0040] 4. For the washing and filtering method of the present invention, under the action of automatic monitoring and adjustment, the water body recycling is more accurate, saving water usage while improving the thoroughness of washing, increasing the washing efficiency, and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0042] The structures, ratios, sizes, etc. depicted in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have technical substantive significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention.

[0043] Figure 1 It is a process flow chart of a circulating gradient fly ash washing system provided for an embodiment of the present invention;

[0044] Figure 2 It is a structural diagram of a filter press equipment in a circulating gradient fly ash washing system provided for an embodiment of the present invention;

[0045] Figure 3 Schematic cross-sectional structure diagram of a plate and frame group in a circulating gradient fly ash water washing system provided by an embodiment of the present invention;

[0046] Figure 4 Partial top view of a plate and frame group in a circulating gradient fly ash water washing system provided by an embodiment of the present invention;

[0047] Figure 5 Flow chart of a circulating gradient fly ash water washing system and method provided by another embodiment of the present invention.

[0048] In the figure:

[0049] 1, fresh water tank; 2, premixing tank; 3-1, first beating tank; 3-2, second beating tank;

[0050] 4-1, first pressure filtration device; 4-2, second pressure filtration device;

[0051] 41, base; 42, support; 43, top frame; 44, hydraulic device;

[0052] 45, pressure filtration assembly;

[0053] 451, plate and frame group;

[0054] 4511, top pressing plate; 4512, bottom pressing plate; 4513, filter plate; 4514, filter cloth; 4515, liquid inlet; 4516, liquid outlet; 4517, isolation membrane; 4518, extrusion chamber; 4519, pressure chamber; 4520, pressure application port; 4521, distribution pipe interface;

[0055] 452, link rod;

[0056] 453, driving rod;

[0057] 46, filter cloth traction mechanism;

[0058] 461, driving roller; 462, pressing roller; 463, rotating shaft; 464, displacement sensor; 465, deviation rectifier; 466, column; 467, pulley; 468, dragging device; 469, steel wire rope;

[0059] 5, water treatment system; 6, drying system; 7, pretreatment filtrate tank; 8, primary water washing filtrate tank; 9, secondary water washing filtrate tank; 10, tertiary water washing filtrate tank; 11, filtrate pump; 12, first water washing pump; 13, second water washing pump; 14, third water washing pump; 15, fresh water pump; 16-1, first beating pump; 16-2, second beating pump; 17, quaternary water washing filtrate tank; 18, fourth water washing pump; 19, ash dissolving water tank; 20, ash dissolving water pump. Detailed Implementation Modes

[0060] The following specific embodiments illustrate the implementation modes of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0061] Terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of clear narration, rather than to limit the scope of implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in technical content, should also be regarded as the scope of implementation of the present invention.

[0062] Embodiment 1:

[0063] As Figure 1 shown, in the first aspect of the implementation mode of the present invention, a circulating gradient fly ash water washing system is provided, including a fresh water tank 1 and a premixing tank 2. The premixing tank 2 is connected to a first pulping tank 3-1. The liquid outlet end of the first pulping tank 3-1 is connected to a first pressure filtration device 4-1. The first pressure filtration device 4-1 includes a plurality of filtrate outlets and a filter cake outlet. The plurality of filtrate outlets are respectively connected to corresponding liquid storage devices. The outlet of the liquid storage device is connected to the first pressure filtration device 4-1, a water treatment system 5, and the premixing tank 2 through a circulation device. The filter cake outlet of the first pressure filtration device 4-1 is connected to a second pulping tank 3-2. The outlet of the second pulping tank 3-2 is connected to a second pressure filtration device 4-2. The second pressure filtration device 4-2 includes a filtrate outlet and a filter cake outlet. The filtrate outlet is connected to a corresponding liquid storage device. The outlet of the filtrate tank is connected to the first pressure filtration device 4-1 through a circulation device. The filter cake outlet is connected to a drying system 6;

[0064] The liquid storage devices are multiple temporary kitchen equipment, specifically including a pretreatment filtrate tank 7, a primary water washing filtrate tank 8, a secondary water washing filtrate tank 9, and a tertiary water washing filtrate tank 10. The pretreatment filtrate tank 7, the primary water washing filtrate tank 8, the secondary water washing filtrate tank 9, and the tertiary water washing filtrate tank 10 are respectively connected to a filtrate pump 11, a first water washing pump 12, a second water washing pump 13, and a third water washing pump 14. The filtrate pump 11 is connected to the water treatment system 5. The first water washing pump 12, the second water washing pump 13, and the third water washing pump 14 are all connected to the liquid inlet end of the first pressure filtration device 4-1;

[0065] Separate control valves are respectively provided at the multiple filtrate outlets of the first pressure filtration device 4-1, and the control valves are independent of each other.

[0066] The liquid outlet end of the first filter press device 4-1 is also connected to the ash dissolving water tank 19. The ash dissolving water tank 19 is connected to the premixing tank 2 through the ash dissolving water pump 20, and the premixing tank 2 is connected to the first pulping tank 3-1.

[0067] The clear water tank 1 is also connected to the second pulping tank 3-2 through the clear water pump 15. The second pulping tank 3-2 and the second filter press device 4-2 are connected through the second pulping pump 16-2.

[0068] Among them, the filtrate outlet of the second filter press device 4-2 is also connected to the four-stage water washing filtrate tank 17. The four-stage water washing filtrate tank 17 is connected to the liquid inlet end of the first filter press device 4-1 through the fourth water washing pump 18.

[0069] Separate control valves are respectively provided at the multiple filtrate outlets of the first filter press device 4-1, and the control valves are independent of each other.

[0070] The liquid outlet end of the first filter press device 4-1 is also connected to the ash dissolving water tank 19. The ash dissolving water tank 19 is also connected to the premixing tank 2 through the ash dissolving water pump 20, and the premixing tank 2 is connected to the first pulping tank 3-1.

[0071] The clear water tank 1 is also connected to the second pulping tank 3-2 through the clear water pump 15. The second pulping tank 3-2 and the second filter press device 4-2 are connected through the second pulping pump 16-2.

[0072] In a more specific structure, the filtrate outlet of the second filter press device 4-2 is also connected to the four-stage water washing filtrate tank 17. The four-stage water washing filtrate tank 17 is connected to the liquid inlet end of the first filter press device 4-1 through the fourth water washing pump 18.

[0073] As Figure 2 shown, the first filter press device 4-1 and the second filter press device 4-2 have the same structure, and both include a base 41. Two groups of support bodies 42 are correspondingly arranged on the base 41. A top frame 43 is installed on the upper part of the support bodies 42. A filter press assembly 45 driven by a hydraulic device 44 is arranged on the support bodies 42. The top of the filter press assembly 45 is provided with a feed end and a water inlet end, and the bottom of the filter press assembly 45 is provided with a filtrate outlet and a filter cake outlet (not shown).

[0074] Furthermore, the filter press assembly 45 is composed of multiple plate and frame groups 451. The sides between the multiple plate and frame groups 451 are connected by link rods 452, and a driving rod 453 connected to the hydraulic device 44 is provided on each plate and frame group 451.

[0075] As Figure 3As shown, the plate and frame group 451 includes a top pressure plate 4511 and a bottom pressure plate 4512, filter chambers are provided on the opposite inner sides of the top pressure plate 4511 and the bottom pressure plate 4512, a filter plate 4513 is provided between the top pressure plate 4511 and the bottom pressure plate 4512, a pull-out filter cloth 4514 is provided on the filter plate 4513, a side surface of the top pressure plate 4511 is provided with a liquid inlet 4515 communicating with the filter chamber inside the top pressure plate 4511, a side surface of the bottom pressure plate 4512 is provided with a liquid outlet 4516 communicating with the filter chamber inside the bottom pressure plate 4512, and the filter plate 4513 is embedded in the bottom pressure plate 4512 so that the contact surface between the bottom pressure plate 4512 and the filter cloth 4514 is a plane.

[0076] During the working process, the mixed liquid enters the filter chamber in the top pressure plate 4511 through the liquid inlet 4515. Under the action of pressure, the filtrate enters the filter chamber in the bottom pressure plate 4512 through the filter cloth 4515 and is discharged through the liquid outlet 4516. The filter cake stays in the filter chamber in the top pressure plate 4511. Both ends of the filter cloth 4514 are filter cake outlets. A filter cake collecting bucket is set at its vertical bottom, which can collect the filter cake in time and transport it outward. The filtrate outlet is the total discharge outlet after the liquid outlets 4516 of all the plate and frame groups 451 are gathered.

[0077] In the specific structure, an isolation membrane 4517 is further provided in the filter cavity of the top pressure plate 4511, an extrusion chamber 4518 is formed between the isolation membrane 4517 and the filter cloth 4514, a pressure chamber 4519 is formed between the isolation membrane 4517 and the inner wall of the top pressure plate 4511, a liquid inlet 4515 is connected to the extrusion chamber 4518, and a pressurizing port 4520 connected to the pressure chamber 4519 is further provided on the side of the top pressure plate 4511;

[0078] During the operation of the filter press equipment 4, the mixed liquid is first squeezed in the filter chamber by its own pressure, but it is completely unable to remove the filtrate with higher removal rate. The pressure chamber 4519 formed on the isolation membrane 4517 is connected to the high-pressure water system at the pressurizing port 4520, and the high-pressure water is pumped into the pressure chamber 4519. At the same time, the stop valve at the liquid inlet 4515 is closed. The high-pressure water in the pressure chamber 4519 applies pressure to the isolation membrane 4517, and squeezes out the filtrate in the filter cake in the squeezing chamber 4518 as much as possible, so that the filter cake is completely agglomerated.

[0079] On the side of the top pressing plate 4511, there is also a distribution pipe interface 4521 communicating with the extrusion chamber 4518. Among them, the distribution pipe interface 4521 is used to dock with an external compressed air device. During the separation of the mixed liquid, the distribution pipe interface 4521 is in a closed state. When the filter cake is completely extruded and formed, the distribution pipe interface 4521 is opened, and compressed air enters the extrusion wall. On the one hand, it can bulge the isolation film 4517 and discharge the extrusion water. On the other hand, while the air flows in the extrusion chamber 4518, it further dries the surface of the filter cake and the moisture inside the extrusion chamber 4518, playing a role in further drying the filter cake and reducing the drying cost of the filter cake during later use.

[0080] See again Figure 2 And Figure 4 As shown, a filter cloth traction mechanism 46 is provided on the base 41. The filter cloth traction mechanism 46 includes a driving roller 461 and a pressing roller 462. The filter cloth 4514 is placed between the driving roller 461 and the pressing roller 462. A rotating shaft 463 is installed on the side walls between two adjacent groups of plate frame groups 451, and the rotating shaft 463 is arranged on both sides in the pulling direction of the filter cloth 4514. According to whether the number of the plate frame groups 451 is odd or even, the filter cloth 4514 is laid on the rotating shaft 463 and forms a circular closed structure.

[0081] The closed-loop structure formed by the filter cloth 4514 circulating and laying on the rotating shaft 463 runs to one side during operation, thereby taking out the filter cake. The filter cake is put into the filter cake collector, and the filter cloth performs the next filtration procedure. When the filter cloth 4514 returns to its original position, first, the filter cloth is rinsed with clean water, and then filtration is carried out to avoid incomplete filtration caused by the blockage of the filter cloth.

[0082] Among them, a displacement sensor 464 and a deviation rectifier 465 are provided at the end of the pressing roller 462. There is also a column 466 on the base 41. Pulleys 467 are provided on both the upper and lower sides of the column 466. A dragging device 468 is provided on the base 41. The steel wire rope 469 in the dragging device 468 is connected to the deviation rectifier 465 through the pulley 467;

[0083] The displacement sensor 464 is used to detect the deviation state of the filter cloth 4514 during operation. If it deviates to a certain side of the rotating shaft 463, the dragging device 468 can make the filter cloth 4514 return to the right track by tightening or loosening the steel wire rope 469, ensuring that the filter cloth 4514 can completely cover the filter cavity.

[0084] Embodiment 2:

[0085] As Figure 5 shown, in another embodiment of the present invention, a fly ash water washing and filtering method includes the following operation steps:

[0086] Ⅰ. Primary fly ash water washing

[0087] The dry ash in the raw material ash bin 21 is introduced into the premixing pipe 2, and a fixed proportion of clear water in the clear water tank 1 is injected into the premixing tank 2 through the clear water pump 15 for mixing. A certain volume of mortar in the premixing tank 2 is discharged into the first beating tank 3-1 through the electric valve. The first beating tank 3-1 is injected into the first pressure filtration device 4-1 through the first beating pump 16-1. The first pressure filtration device 4-1 is tightly closed. At the same time, the control valve connecting to the pretreatment filtrate tank 7 is opened, and the filtrate enters the pretreatment filtrate tank 7 and is stored, while the filter cake remains in the filter chamber;

[0088] The clear water in the clear water tank 1 is injected into the first pressure filtration device 4-1 through the clear water pump 15. At the same time, the control valve connecting to the primary water washing filtrate tank 8 is opened, and the filtrate enters the primary water washing filtrate tank 8 and is stored, while the filter cake remains in the filter chamber;

[0089] The clear water in the clear water tank 1 is again injected into the first pressure filtration device 4-1 through the clear water pump 15 to rinse the filter cake with clear water. The first pressure filtration device 4-1 is tightly closed. At the same time, the control valve connecting to the secondary water washing filtrate tank 9 is opened, and the filtrate enters the secondary water washing filtrate tank 9 and is stored, while the filter cake remains in the filter chamber;

[0090] The clear water in the clear water tank 1 is again injected into the first pressure filtration device 4-1 through the clear water pump 15 to rinse the filter cake with clean water. The first pressure filtration device 4-1 is tightly closed. At the same time, the control valve connecting to the tertiary water washing filtrate tank 10 is opened, and the filtrate enters the tertiary water washing filtrate tank 10 and is stored, while the filter cake is sent to the second beating tank 3-2;

[0091] The clear water in the clear water tank 1 is injected into the second beating tank 3-2 through the clear water pump 15, stirred for 30 minutes, and then sent to the second pressure filtration device 4-2 through the second beating pump 16-2. The second pressure filtration device 4-2 is tightly closed. At the same time, the control valve connecting to the quaternary water washing filtrate tank 17 is opened, and the filtrate enters the quaternary water washing filtrate tank 17 and is stored, while the filter cake remains in the filter chamber;

[0092] At this time, the salt content concentration of the filter cake is the lowest and can reach the reuse standard, and the filter cake is discharged;

[0093] Ⅱ. Circulating water washing

[0094] The first-stage water-washing filtrate tank 8 is led into the ash-dissolving water tank 19 through the first water-washing pump 12, and is mixed evenly with dry ash to form ash slurry. The ash-dissolving water pump 20 injects the ash slurry into the premixing tank 2, and it enters the first pressure filtration device 4-1 through the first beating tank 3-1. After pressure filtration, the filtrate enters the pretreatment filtrate tank 7. Then, the filtrate in the second-stage water-washing filtrate tank 9 enters the first pressure filtration device 4-1 through the second water-washing pump 13, and the control valve connecting the first-stage water-washing filtrate tank 8 is opened, and the filtrate enters the first-stage water-washing filtrate tank 8. Then, the filtrate in the third-stage water-washing filtrate tank 10 is sent to the first pressure filtration device 4-1 through the third water-washing pump 14, and the control valve connecting the second-stage water-washing filtrate tank 9 is opened, and the filtrate enters the second-stage water-washing tank 9. Then, the filtrate in the fourth-stage water-washing filtrate tank 17 is sent to the first pressure filtration device 4-1 through the fourth water-washing pump 18, and the control valve connecting the third-stage water-washing filtrate tank 10 is opened, and the filtrate enters the third-stage water-washing tank 10. Then, the filter cake is sent into the second beating tank 3-2, and the clear water in the clear water tank 1 is sent into the second beating tank 3-2 through the clear water pump 15, stirred for 30 minutes, and sent to the second pressure filtration device 4-2 through the second beating pump 16-2, and the control valve connecting the fourth-stage water-washing filtrate tank 17 is opened, and the filtrate enters the fourth-stage water-washing filtrate tank 17, and the filter cake is sent to the drying system 6;

[0095] Among them, the working processes of the first pressure filtration device 4-1 and the second pressure filtration device 4-2 are the same. Taking the first pressure filtration device 4-1 as an example, the working process of the first pressure filtration device 4-1 is to inject the ash slurry into the first pressure filtration device 4-1, and the filtrate is discharged from the filtrate outlet through the filter cloth 4514, and the filter cake remains in the filter cavity for rinsing;

[0096] After the filter cake after repeated rinsing meets the standard, high-pressure water is pumped into the pressure chamber 4519 through the pressure port 4520. Under the action of the high-pressure water, the isolation membrane 4517 approaches the filter plate 4514, forcing the filter cake in the extrusion chamber 4518 to drain the water and form lumps, and the high-pressure water is stopped;

[0097] Air is blown into the extrusion chamber 4518 through the distribution pipe. The air bulges the isolation membrane 4517 and discharges all the high-pressure water. At the same time, through air exchange, the remaining water is discharged through the drain port, and the filter cake is further dried;

[0098] The hydraulic device 44 is started, the driving rod 453 opens the top pressing plate 4511 and the bottom pressing plate 4512 of the plate frame group 451, the driving roller is started, and the filter cloth 4514 runs in a cycle, and the filter cake is discharged from both ends of the filter cloth 4514 of the plate frame group 451.

[0099] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it on the basis of the present invention, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A circulating gradient fly ash water washing system, comprising a fresh water tank and a premixing tank, characterized in that, The pre-mixing tanks are all connected to the first beating tank. The liquid outlet end of the first beating tank is connected to the first pressure filtration device. The first pressure filtration device includes a plurality of filtrate outlets and a filter cake outlet. The plurality of filtrate outlets are respectively connected to corresponding liquid storage devices. The outlet of the liquid storage device is connected to the first pressure filtration device, the water treatment system, and the pre-mixing tank through a circulation device. The filter cake outlet of the first pressure filtration device is connected to the second beating tank. The outlet of the second beating tank is connected to the second pressure filtration device. The second pressure filtration device includes a filtrate outlet and a filter cake outlet. The filtrate outlet is connected to the corresponding liquid storage device. The outlet of the filtrate tank is connected to the first pressure filtration device through a circulation device. The filter cake outlet is connected to the drying system; The liquid storage devices include a pretreatment filtrate tank, a primary water washing filtrate tank, a secondary water washing filtrate tank, and a tertiary water washing filtrate tank. The pretreatment filtrate tank, the primary water washing filtrate tank, the secondary water washing filtrate tank, and the tertiary water washing filtrate tank are respectively connected to a filtrate pump, a first water washing pump, a second water washing pump, and a third water washing pump. The filtrate pump is connected to the water treatment system. The first water washing pump, the second water washing pump, and the third water washing pump are all connected to the liquid inlet end of the first pressure filtration device; Separate control valves are respectively provided at the multiple filtrate outlets of the first pressure filtration device, and the control valves are independent of each other; Inject the clear water in the clear water tank into the first pressure filtration device through a clear water pump. The liquid outlet end of the first pressure filtration device is connected to a lime dissolving water tank. The lime dissolving water tank is also connected to the pre-mixing tank through a lime dissolving water pump. The pre-mixing tank is connected to the first beating tank; the clear water tank is also connected to the second beating tank through a clear water pump. The second beating tank and the second pressure filtration device are connected through a second beating pump; the filtrate outlet of the second pressure filtration device is also connected to a fourth water washing filtrate tank. The fourth water washing filtrate tank is connected to the liquid inlet end of the first pressure filtration device through a fourth water washing pump.

2. The circulating gradient fly ash water washing system according to claim 1, characterized in that, Both the first pressure filtration device and the second pressure filtration device include a base. Two groups of support bodies are correspondingly arranged on the base. A top frame is installed on the upper part of the support body. A pressure filtration component driven by a hydraulic device is arranged on the support body. The front and rear sides of the pressure filtration component are provided with a feed end, a water inlet end, and a filtrate outlet. The filter cake outlet is arranged on the left and right sides of the pressure filtration component.

3. The circulating gradient fly ash water washing system according to claim 2, characterized in that, The pressure filtration component is composed of a plurality of plate-frame groups. The sides between the plurality of plate-frame groups are connected by link rods. A driving rod connected to the hydraulic device is arranged at the bottom of the plate-frame group; The plate-frame group includes a top pressing plate and a bottom pressing plate. Filter cavities are provided on the relative inner sides of the top pressing plate and the bottom pressing plate. A filter plate is arranged between the top pressing plate and the bottom pressing plate. A drawable filter cloth is arranged on the filter plate. A liquid inlet communicating with the inner filter cavity is arranged on one side of the top pressing plate. A liquid outlet communicating with the inner filter cavity is arranged on one side of the bottom pressing plate. The filter plate is embedded in the bottom pressing plate, so that the contact surface between the bottom pressing plate and the filter cloth is a plane.

4. The circulating gradient fly ash water washing system according to claim 3, characterized in that, An isolation membrane is further arranged in the filter cavity of the top pressing plate. An extrusion chamber is formed between the isolation membrane and the filter cloth. A pressure chamber is formed between the isolation membrane and the inner wall of the top pressing plate. The liquid inlet is communicated with the extrusion chamber. A pressure adding port communicated with the pressure chamber is further arranged on the side of the top pressing plate; A distribution pipe interface communicating with the extrusion chamber is further provided on the side surface of the top pressing plate.

5. The circulating gradient fly ash water washing system according to claim 3, characterized in that, A filter cloth traction mechanism is provided on the base. The filter cloth traction mechanism includes a driving roller and a pressing roller. The filter cloth is disposed between the driving roller and the pressing roller. Rotating shafts are installed at the front and rear ends between adjacent two groups of plate frame groups, and the rotating shafts are arranged at both ends in the drawing direction of the filter cloth. The filter cloth is laid on the rotating shafts to form a circulating closed structure.

6. The circulating gradient fly ash water washing system according to claim 5, characterized in that, A displacement sensor and an adjusting wheel are provided at the end of the pressing roller. Columns are further provided on the base. Pulleys are provided on both the upper and lower sides of the columns. A dragging device is provided on the base. The connecting rod in the dragging device is connected to the adjusting wheel through the pulleys.

7. A circulating gradient fly ash water washing method, characterized in that, It includes the following operation steps: Ⅰ. Primary washing of fly ash A certain volume of mortar in the premixing tank is put into the first beating tank through an electric valve. The first beating tank is injected into the first pressure filtering device through a beating pump. The first pressure filtering device is tightly closed. At the same time, the control valve connecting to the pretreatment filtrate tank is opened, and the filtrate enters the pretreatment filtrate tank and is stored. The filter cake remains in the filter cavity. Clear water in the clear water tank is injected into the pressure filtering device through a clear water pump. At the same time, the control valve connecting to the first-stage washing filtrate tank is opened, and the filtrate enters the first-stage washing filtrate tank and is stored. The filter cake remains in the filter cavity. Again, clear water in the clear water tank is injected into the pressure filtering device through a clear water pump, so that the filter cake is rinsed with clear water. The pressure filtering device is tightly closed. At the same time, the control valve connecting to the second-stage washing filtrate tank is opened, and the filtrate enters the second-stage washing filtrate tank and is stored. The filter cake remains in the filter cavity. Again, clear water in the clear water tank is injected into the pressure filtering device through a clear water pump, so that the filter cake is rinsed with clear water. The pressure filtering device is tightly closed. At the same time, the control valve connecting to the third-stage washing filtrate tank is opened, and the filtrate enters the third-stage washing filtrate tank and is stored. The filter cake is sent to the second beating tank. Clear water in the clear water tank is injected into the second beating tank through a clear water pump, stirred for 30 minutes, and sent to the second pressure filtering device through a second beating pump. The second pressure filtering device is tightly closed. At the same time, the control valve connecting to the fourth-stage washing filtrate tank is opened, and the filtrate enters the fourth-stage washing filtrate tank and is stored. The filter cake remains in the filter cavity. At this time, the salt content concentration of the filter cake is the lowest and can reach the reuse standard, and the filter cake is discharged. Ⅱ. Circulating washing The first-stage water-washing filtrate tank is introduced into the lime slaking water tank through the first water-washing pump, and is mixed evenly with dry lime to form lime slurry. The lime slurry enters the pressure filtration equipment through the beating pump, and the filtrate enters the pre-treatment filtrate tank. Then, the filtrate in the second-stage water-washing filtrate tank enters the pressure filtration equipment through the second water-washing pump, and the control valve connecting the first-stage water-washing filtrate tank is opened, and the filtrate enters the first-stage water-washing filtrate tank. Then, the filtrate in the third-stage water-washing filtrate tank is sent to the pressure filtration equipment through the third water-washing pump, and the control valve connecting the second-stage water-washing filtrate tank is opened, and the filtrate enters the second-stage water-washing tank. Then, the filtrate in the fourth-stage water-washing filtrate tank is sent to the pressure filtration equipment through the fourth water-washing pump, and the control valve connecting the third-stage water-washing filtrate tank is opened, and the filtrate enters the third-stage water-washing tank. Then, the filter cake is sent into the second beating tank, and the clear water in the clear water tank is sent into the second beating tank through the clear water pump, stirred for 30 minutes, sent to the second pressure filtration equipment through the second beating pump, and the control valve connecting the fourth-stage water-washing filtrate tank is opened, and the filtrate enters the fourth-stage water-washing filtrate tank, and the filter cake is sent to the drying system; Among them, the working process of the first pressure filtration equipment is as follows: the lime slurry is injected into the pressure filtration equipment, the filtrate is discharged from the filtrate outlet through the filter cloth, and the filter cake remains in the filter chamber for rinsing; After the filter cake after repeated rinsing meets the standard, high-pressure water is pumped into the pressure chamber through the pressure inlet. Under the action of the high-pressure water, the isolation membrane approaches the filter plate, forcing the filter cake in the extrusion chamber to drain the water and form lumps, and the high-pressure water is stopped; Air is blown into the extrusion chamber through the distribution pipe, the air bulges the isolation membrane and discharges all the high-pressure water. At the same time, through air exchange, the residual water is discharged through the drain port, and the filter cake is further dried; Among them, the working process of the second pressure filtration equipment is as follows: the lime slurry is injected into the pressure filtration equipment, the filtrate is discharged from the filtrate outlet through the filter cloth, and the filter cake remains in the filter chamber; High-pressure water is pumped into the pressure chamber through the pressure inlet. Under the action of the high-pressure water, the isolation membrane approaches the filter plate, forcing the filter cake in the extrusion chamber to drain the water and form lumps, and the high-pressure water is stopped; Air is blown into the extrusion chamber through the distribution pipe, the air bulges the isolation membrane and discharges all the high-pressure water. At the same time, through air exchange, the residual water is discharged through the drain port, and the filter cake is further dried; The hydraulic device is started, the driving rod opens the top pressing plate and the bottom pressing plate of the plate-frame group, the driving roller is started, the filter cloth runs in a cycle, and the filter cake is discharged from both ends of the filter cloth plate-frame group.

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