Background
The dredging of river, lake and drainage pipe networks is a necessary step for solving the water body treatment, but the slurry produced by the traditional dredging construction mode is treated nearby in landfill to become a secondary pollution source, and the slurry centralized treatment mode without secondary pollution has the defects of high slurry transportation cost, low speed and large land occupation, and becomes a bottleneck factor for restricting the water body treatment.
At present, most dredging construction enterprises adopt a dredging construction mode without secondary pollution as follows: firstly, dam building and flow cutting operation is carried out, then, a water gun is used for scattering bottom sludge, then, the sludge is pumped to a tank truck to be transported to a treatment field for storage, and finally, sedimentation concentration and filter pressing dewatering are carried out in the treatment field to form sludge cakes for external transportation and landfill. This traditional mode of operation is time-consuming and labor-consuming, and in particular the slurry transport link takes up more than half of the processing cost.
The ability to dewater the slurry in situ at the dredging site remains a bottleneck in dredging operations. At present, a new technology such as a spiral shell stacking machine dewatering method does not appear, but compared with the existing slurry dewatering production, the traditional dewatering technology with high energy consumption, centrifugal force separation and the like and low treatment speed is the main flow.
1. Conventional slurry dewatering method
At present, a high-pressure plate frame filtering method, a horizontal screw centrifugal separation method, a belt type filter pressing method and the like are widely used in the slurry dehydration method.
1. High-pressure plate frame filtering method
The high-pressure plate frame filtering is an intermittent filtering dehydration method, is generally used for dehydrating a small amount of slurry, and has the advantages of large plate frame filtering device, high installation power and stable bearing foundation. High pressure plate frame filtration is generally suitable for use in stationary mud treatment plants, and is less suitable for use in the crude environment of dredging mud producing sites.
2. Horizontal spiral centrifugal separation method
The horizontal spiral centrifugal separation method is a continuous filtering dehydration method, is generally used for dehydrating mud with small density and small quantity, and a large-sized centrifugal machine has huge volume and high installation power, needs a particularly stable foundation and is not suitable for being used in places where frequent movement is performed. The decanter centrifuge is generally suitable for use in a stationary mud processing plant and is generally not suitable for use in a crude environment at the site of the dredging mud producing site.
3. Belt press filtration method
The belt press method is a continuous filtration and dehydration method, and is generally used for slurry dehydration treatment which is easier to filter. Large belt filter presses are large in size, high in installation accuracy, high in technical requirements for maintenance and the need for a stable bearing foundation. Belt filter presses are generally suitable for use in stationary mud treatment plants and are less suitable for use in the crude environment of dredging mud producing areas.
2. New method for dewatering mud
The slurry dehydration method is the most widely used main stream method in China at present. In recent years, new slurry dewatering methods are also emerging, and a lap screw press dewatering method is typical.
The main body of the spiral pressing dehydrator is formed by mutually laminating a fixed ring and a movable ring, a spiral shaft penetrates through a filtering device formed in the fixed ring and the movable ring, the front section is a concentrating part, the rear section is a dehydrating part, and a filtering seam formed between the fixed ring and the movable ring and the pitch of the spiral shaft gradually become smaller from the concentrating part to the dehydrating part. After the mud is flocculated and concentrated in the concentrating part, the mud is pushed to the dewatering part by the screw shaft, and the mud is gradually reduced along with the filter seam and the screw pitch in the advancing process and under the blocking action of the back pressure plate, so that the volume is continuously reduced, and the aim of full dewatering is fulfilled.
The spiral shell press dehydrator has smaller power and small device volume, and gradually becomes the first choice for dehydrating the residual activated sludge of the sewage plant, but because the dehydration depends on the dehydration of the filter gap formed between the fixed ring and the movable ring, when sand exists in slurry, the fine sand can be extruded into the filter gap, so that the filter gap is enlarged, the slurry and the water directly come out of the filter gap, and the spiral shell press dehydration cannot be performed; in addition, after sand enters the filter gap, grooves are milled on the fixed ring, the movable ring and the screw shaft, and the fixed ring, the movable ring and the screw shaft are scrapped and need to be replaced. Because a large amount of sand is commonly existed in the dredging slurry, and the removal of the sand is basically impractical, the dewatering effect of the dredging slurry of the spiral shell stacking machine is very unstable, and the service life of main components is very short due to the abrasion of the sand, so that the spiral shell stacking machine is still difficult to adapt to mass production application at present.
Disclosure of Invention
The invention aims to solve the technical problem of realizing rapid, low-energy-consumption and stable dehydration of a large amount of dredging slurry on a production site.
In order to solve the technical problems, the technical scheme of the invention is to provide a system for on-site dehydration of slurry, which is characterized in that: the device comprises a screening device for removing slag from slurry, wherein a slurry outlet of the screening device is connected with a flocculation concentrator, a sewage outlet of the flocculation concentrator is connected with a water collecting tank, a concentrated slurry outlet of the flocculation concentrator is connected with a mixer inlet through a slurry pump, a dispensing tank for configuring slurry tackifier is connected with the mixer inlet, the mixer outlet is connected with a slurry feeding pipe of a slurry dewatering device, a mud ball outlet of the slurry dewatering device is connected with a mud inlet of a mud-water separation device, a water outlet of the slurry dewatering device is connected with the water collecting tank and the dispensing tank, and a mud outlet of the mud-water separation device is connected with a screw extrusion conveyor;
the mud dewatering device comprises a rotary drum and a driving device for driving the rotary drum to rotate; the rotary drum is formed by connecting a rotary drum straight pipe section and a rotary drum taper pipe section, the other end of the rotary drum straight pipe section is provided with a water outlet overflow port, and the other end of the rotary drum taper pipe section is provided with a mud ball outlet; spiral plates are arranged on the inner walls of the straight tube section of the rotary drum and the conical tube section of the rotary drum, and a spiral channel with a through center is formed in the rotary drum from the overflow outlet of the water to the mud ball outlet; the mud feeding pipe is inserted into the straight pipe section of the rotary drum from the water outlet overflow port;
the mud-water separation device comprises a screen drum and a driving device for driving the screen drum to rotate; the two ends of the screen cylinder are provided with baffle plates, the baffle plate at one end is provided with a mud inlet, and the baffle plate at the other end is provided with a mud outlet; the screen surface of the screen cylinder is formed by winding stainless steel wires into a spiral shape.
Preferably, the driving device for driving the rotary drum to roll comprises a roller arranged at the bottom of the rotary drum, a rotating track is arranged on the outer wall of the rotary drum along the circumferential direction, the rotary drum is supported on the roller through the rotating track, and the roller is connected with a driving motor. The roller drives the rotary drum to rotate along the rotating track through friction force with the rotating track.
Preferably, the rotation speed of the rotary drum ranges from 0 to 10rpm.
Preferably, the cone angle of the cone tube section of the rotary drum is 10-90 degrees.
Preferably, the central through spiral channel formed by the spiral plate in the straight tube section of the rotary drum extends to the overflow water outlet, and the central through spiral channel formed by the spiral plate in the conical tube section of the rotary drum extends to the mud ball outlet.
Preferably, in the cone pipe section of the rotary drum, the spiral channel gradually contracts and becomes smaller from one end connected with the straight pipe section of the rotary drum to the mud ball outlet.
Preferably, the inserted mud feed pipe is inserted into the straight tube section of the rotary drum to a depth of 20% -100% of the length of the straight tube section of the rotary drum; and a space is kept between the outer wall of the inserted mud feeding pipe and the water outlet overflow port.
Preferably, a countercurrent inner cylinder for gathering and guiding the flow of the dewatering water to the overflow port is arranged in the cone pipe section of the rotary drum.
Preferably, the countercurrent inner cylinder is funnel-shaped and is one-section continuously contracted or is contracted in multiple sections; holes for water to enter are densely distributed on the peripheral wall of the countercurrent inner cylinder.
More preferably, the maximum diameter of the countercurrent inner cylinder is smaller than or equal to the diameter d of the inner opening of the spiral plate of the straight tube section of the rotary cylinder, the diameter of the straight tube section of the rotary cylinder is 1.1 d-10 d, the minimum diameter of the countercurrent inner cylinder is 0.05 d-0.5 d, the length of the countercurrent inner cylinder is 0.2-2 times of the length of the conical tube section of the rotary cylinder, the diameter ratio of the length of the straight tube section of the rotary cylinder to the length of the straight tube section of the rotary cylinder is 1-10, and the pitch of the spiral plate is 0.05 d-0.5 d.
Preferably, the driving device for driving the screen cylinder to rotate comprises a roller wheel arranged at the bottom of the screen cylinder, a guide rail groove is formed in the outer wall of the screen cylinder along the circumferential direction, the screen cylinder is supported on the roller wheel through the guide rail groove, and the roller wheel is connected with a driving motor; the roller drives the screen cylinder to rotate along the guide rail groove through friction force with the guide rail groove;
preferably, one or more rows of backflushing cleaning spray heads are distributed outside the screen cylinder along the axial direction, and the backflushing cleaning spray heads are connected with an air inlet pipe for supplying compressed air and/or a water inlet pipe for supplying cleaning water with pressure, so that non-filtering parts of the screen cylinder are dredged from outside to inside.
Preferably, a mud bucket is arranged at the bottom of the mud outlet.
Preferably, the rotation speed of the screen drum ranges from 0rpm to 10rpm.
Preferably, the section of the stainless steel wire is trapezoidal.
Preferably, the strip-shaped sieve holes formed between the stainless steel wires of adjacent circles are of an inner narrow and outer wide structure.
Preferably, the screen surface is externally provided with axial support ribs.
Preferably, the aspect ratio of the screen drum is 1-10.
The invention also provides a method for on-site dehydration of the slurry, which is characterized by comprising the following steps:
step 1: adding flocculant into the slurry after deslagging by a sieving device, uniformly mixing and flowing into a flocculation concentrator, discharging sewage separated by the flocculation concentrator into a water collecting tank, and discharging concentrated slurry separated by the flocculation concentrator into a mixer by a slurry pump;
step 2: adding tackifier arranged in a dispensing tank into a mixer, and uniformly mixing to form viscous slurry;
step 3: the viscous slurry enters a slurry dehydration device, and as the surfaces of particles in the slurry are viscous, the particles in the slurry are mutually bonded and rolled and kneaded to grow into mud balls in the rotation process of the slurry carried by a rotary drum, and the mud balls are wrapped with water and extruded through a mud ball outlet at the end part of a conical pipe section of the rotary drum to enter a mud inlet of a mud-water separation device; meanwhile, in the rotation process of the mud ball, the water squeezed by the mud ball flows out from a water outlet overflow port at the end part of the straight pipe section of the rotary drum; delivering a part of the discharged water to a dispensing tank, discharging the rest of the discharged water to a water collecting tank, and discharging the water in the water collecting tank on site or using the water as sludge flushing water;
step 4: in the mud-water separation device, a screen drum rotates, water wrapped by mud clusters is screened out and flows into a water collecting tank, the mud clusters roll along a screen surface and move towards a mud outlet by utilizing thrust provided by a spiral stainless steel wire, and finally dehydrated mud is discharged from the mud outlet;
step 5: and finally dehydrating the mud balls discharged from the mud-water separation device into mud blocks through a screw extrusion conveyor, and loading and transporting the mud blocks.
Preferably, in the step 2, the tackifier is one or a mixture of several of polyacrylonitrile, polyacrylamide and glycan.
The system provided by the invention overcomes the defects of the prior art, can realize on-site massive and rapid dehydration of slurry, has the processing speed of more than 5 times and the processing speed of more than 2.5 times compared with the conventional plate-frame filtering processing system with the same installed power, occupies the floor area which is only 50% of that of the conventional plate-frame filtering processing method, and has the advantages of low energy consumption, continuous operation, simplicity, reliability, long service life and good stability.
Detailed Description
The invention will be further illustrated with reference to specific examples. It is to be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. Further, it is understood that various changes and modifications may be made by those skilled in the art after reading the teachings of the present invention, and such equivalents are intended to fall within the scope of the claims appended hereto.
Fig. 1 is a schematic diagram of a system for on-site dehydration of slurry, which consists of a sieving device 1, a flocculation concentrator 2, a water collecting tank 3, a slurry pump 4, a mixer 5, a tempering agent dispensing tank 6, a slurry dehydration device 7, a slurry-water separation device 8, a screw extrusion conveyor 9 and the like.
The screening device 1 is used for deslagging to mud, the mud outlet of screening device 1 is connected with flocculation concentrator 2, the sewage outlet of flocculation concentrator 2 is connected with water catch bowl 3, the concentrated mud outlet of flocculation concentrator 2 is connected with the blender 5 entry through slush pump 4, dispense jar 6 and connect blender 5 entry, blender 5 exit is connected with the mud inlet pipe of mud dewatering device 7, mud ball exit linkage mud water separator 8 of mud dewatering device 7 goes into mud mouth, the water outlet of deviating from of mud dewatering device 7 is connected with water catch bowl 5 and dispense jar 6, screw extrusion conveyer 9 is connected to mud separator 8's play mud mouth.
The flocculation concentrator 2 is provided with a mixing chamber at the inlet, a stirrer 21 is arranged in the mixing chamber, and a flocculant adding inlet is also arranged in the mixing chamber. The top of the outlet of the flocculation concentrator 2 is provided with an overflow port 22, and the bottom of the flocculation concentrator 2 is provided with a concentrated slurry outlet 23.
The dispensing tank 6 is used for dispensing a viscosity increasing agent for increasing viscosity of the slurry.
Referring to fig. 2, the slurry dewatering apparatus 7 is composed of an insert-type slurry feed pipe 71, a water-out overflow port 72, a straight tube section 73 of a drum, a first driven roller 74, a first driving roller 75, a rotation rail 76, a cone tube section 77 of the drum, a mud ball outlet 78, a countercurrent inner tube 79, and the like.
The rotary drum is formed by connecting a rotary drum straight pipe section 73 and a rotary drum cone pipe section 77, a water outlet overflow port 72 is formed at the other end of the rotary drum straight pipe section 73, and a mud ball outlet 78 is formed at the other end of the rotary drum cone pipe section 77. The cone angle of the cone section 77 of the drum is 10 deg. to 90 deg.. The inner walls of the straight tube section 73 and the conical tube section 77 of the rotating tube are respectively provided with a spiral plate, a central through spiral channel formed by the spiral plates in the straight tube section 73 of the rotating tube is communicated and extends to the overflow water outlet 72, a central through spiral channel formed by the spiral plates in the conical tube section 77 of the rotating tube is communicated and extends to the mud ball outlet 78, and a central through spiral channel is formed in the rotating tube from the overflow outlet 72 of the water to the mud ball outlet 78.
The bottom of the rotary drum is provided with a first driven roller 74 and a first driving roller 75, the outer wall of the rotary drum is provided with a rotating rail 76, and the rotating rail 76 of the rotary drum is supported on the first driven roller 74 and the first driving roller 75. The rollers rotate the drum by friction with the rotation rail 76, and the first driving roller 75 provides power required for rotation, and the first driven roller 74 passively rotates and supports the drum together with the first driving roller 75. The rotational speed of the drum is controlled by adjusting the rotational speed of the first driving roller 75 in the range of 0 to 10rpm.
The inserted mud feeding pipe 11 is inserted into the straight tube section 73 of the rotary drum from the water outlet overflow port 72, and the insertion depth is 20% -100% of the straight tube section 73 of the rotary drum. The plug-in feed pipe 71 is used for feeding slurry into the rotary drum, particles in the slurry are mutually bonded and rolled and kneaded to grow into mud clusters through a spiral channel, the mud clusters roll to grow and are deposited in a deposition tank at the underwater part, and when the rotary drum rotates, the spiral channel forms a pushing force from the straight tube section 73 of the rotary drum to the direction of the conical tube section 77 of the rotary drum to push the mud clusters to move towards the mud cluster outlet 78. After the mud pit moves to the cone section 77 of the rotary drum, the internal channel gradually contracts and becomes smaller, and finally the mud pit extends to the mud pit outlet 78, the mud pit presses the rotary drum to dewater, and finally the mud pit is discharged out of the rotary drum from the mud pit outlet 78.
The countercurrent inner cylinder 79 is arranged in the cone section 77 of the rotary cylinder, the countercurrent inner cylinder 79 is funnel-shaped (the opening of one end close to the mud ball outlet 78 is smaller), small holes are densely distributed on the countercurrent inner cylinder 79, and countercurrent water enters the countercurrent inner cylinder 79 from the small holes and flows towards the direction of the water outlet overflow port 72. The outer wall of the inserted mud feeding pipe 71 and the overflow outlet 72 are kept at a certain interval, so that the water can smoothly flow out from the overflow outlet 72.
The inner diameter of the countercurrent inner cylinder 79 can be one section of continuous shrinkage or multi-section shrinkage, the diameter of the largest part of the countercurrent inner cylinder 79 is smaller than or equal to the diameter d of the opening in the spiral plate of the straight tube section 73 of the rotary cylinder, the diameter of the straight tube section 73 of the rotary cylinder is 1.1 d-10 d, the diameter of the smallest part of the countercurrent inner cylinder 79 is 0.05 d-0.5 d, the length of the countercurrent inner cylinder 79 is 0.2-2 times of the length of the conical tube section 77 of the rotary cylinder, the diameter ratio of the length of the straight tube section of the rotary cylinder to the diameter of the straight tube section of the rotary cylinder is 1-10, and the pitch of the spiral plate is 0.05 d-0.5 d.
When the slurry dewatering device is used, the first driving roller 75 drives the rotary drum to rotate at a low speed along the rotating track 76, and the first driven roller 74 for supporting the rotary drum in an auxiliary manner also rotates synchronously; after the slurry is regulated by the viscosity-adding agent, the slurry enters a straight tube section 73 of the rotary drum through an inserted slurry feed tube 71, the rotation of the rotary drum drives the slurry to rotate together, and the slurry is constrained by a spiral channel formed by a spiral plate in the rotary drum and is pushed to the direction of a mud ball outlet 78; in the rotating process, sand in the slurry is taken as cores, sticky floccules in the slurry are increasingly adsorbed on the cores to form mud balls, the mud balls grow like snowballs, and the water in the mud balls is extruded by the self weight of the mud balls; after the mud ball moves to the cone pipe section 77 of the rotary drum, the channel formed by the spiral plate in the mud ball gradually contracts and becomes smaller, the mud ball is extruded and further dehydrated, and finally the mud ball is discharged out of the cone pipe section 77 from the mud ball outlet 78; while the mud water moves to the mud ball outlet 78 from the cone pipe section 77 of the rotary drum, the mud water level is raised to a backward countercurrent beyond the height of the spiral plate, the countercurrent inner cylinder 79 is in a funnel shape, small holes are densely distributed on the countercurrent inner cylinder 79, and countercurrent water flows from the small holes into the countercurrent inner cylinder 79 to the direction of the water outlet overflow port 72; in the straight tube section 73 of the rotary drum, the de-watering water flows reversely through the spiral plate in the straight tube section step by step, and flows out of the rotary drum from the de-watering water overflow port 72, so that the de-watering water is discharged in an unpowered manner.
Under the dehydration mode, along with the continuous growth of the mud ball, the surface area of the mud ball is multiplied, the speed of the mud ball adhering to particles in mud is higher, and the mud ball is accelerated like a snowball, so that the device can easily treat mud in a rapid and large scale, and the dehydration process is finished mainly by means of gravity extrusion of the mud ball, so that the energy consumption of dehydration is low.
Referring to fig. 3, the mud-water separator 8 is composed of a mud inlet 81, a baffle 82, a screen cylinder 83, a guide rail groove 84, a second driving roller 85, a second driven roller 86, a mud outlet 87, a mud bucket 88, a screen surface 89, a backflushing cleaning nozzle 810, an air inlet/water inlet pipe 811, and the like.
The two ends of the screen cylinder 83 are provided with baffle plates 82, the baffle plate 82 at one end is provided with a mud inlet 81, and the baffle plate 82 at the other end is provided with a mud outlet 87. A mud bucket 88 is arranged at the bottom of the mud outlet 87.
Two circles of guide rail grooves 84 are formed in the periphery of the screen surface 89 of the screen cylinder 83, the second driving roller 85 and the second driven roller 86 are arranged at the bottom of the screen cylinder 83, and the screen cylinder 83 is supported on the second driving roller 85 and the second driven roller 86 through the guide rail grooves 84. The roller drives the screen cylinder 3 to rotate by friction with the track groove 84, and the rotation speed of the screen cylinder 83 is controlled by adjusting the rotation speed of the second driving roller 85, and the rotation speed range of the screen cylinder 83 is 0-10 rpm.
Referring to fig. 4, the screen surface 89 is formed by winding stainless steel wires 812 having a trapezoidal cross section in a spiral shape, and strip-shaped mesh openings 814 formed between the stainless steel wires of adjacent turns have a structure with a narrow inner portion and a wide outer portion. When the direction of movement of the mud pit is the same as the direction of the spiral around which the stainless steel wire is wound, the spiral stainless steel wire on the screen surface 89 provides the motive force to propel the mud pit to move in the direction of the mud outlet 87 when rotated.
The screen surface 89 is externally provided with axial support ribs 813 to ensure the strength of the screen surface.
The aspect ratio of the screen cylinder 83 is 1 to 10.
When the mud-water separation device is used, the second driving roller 85 drives the screen cylinder 83 to rotate along the guide rail groove 84, and the driven roller 86 with auxiliary supporting function is also driven to synchronously rotate; after the cement clusters enter the rotary screen cylinder 83 from the mud inlet 81, the screen cylinder 83 rotates with the cement clusters, and water carried by the cement clusters is filtered out through the screen holes on the screen surface 89; the thrust action generated by the spiral rotation of the baffle 82 and the screen surface 89 causes the mud ball to move towards the mud outlet 87 and roll out from the mud outlet 87 to the mud bucket 88 for output.
In order to prevent the silt from blocking the sieve holes on the screen surface 89 and affecting the water filtering capacity of the screen cylinder 83, one or more rows of backflushing and cleaning nozzles 810 are distributed outside the screen cylinder 83 along the axial direction, and the backflushing and cleaning nozzles 810 supply compressed air/cleaning water with pressure through an air inlet/water inlet pipe 811 to dredge the sieve holes from outside to inside at the non-filtering part of the screen cylinder 83.
The invention is further illustrated by the following examples.
Example 1
A system for in situ dewatering of a slurry is shown in figure 1.
a) Will be 60m 3 The dredging slurry with 98.0% of water content of H enters a screening device to screen out residues which may block or damage pipeline equipment, the slurry flows into a stirring tank and is added with flocculating agent polyferric chloride, the flocculating agent and the slurry are uniformly mixed by the stirring device and are subjected to flocculation reaction, and overflow water is discharged for 30m 3 H, the water content of the slurry concentrated at the bottom reaches 96.0%;
b)30m 3 lifting/H concentrated slurry by a pump, adding polyacrylonitrile solution, mixing, feeding into a slurry dewatering device, and overflowing water for 18.6m in the rotating process 3 A small part of overflow water returns to the dispensing tank for conditioning and thickening agents, and mud clusters enter a mud-water separation device;
c) In the mud-water separation device, a rotary screen drum screens out water wrapped in mud clusters to obtain mud clusters with water content of 75.5% of 4.9m 3 /H。
d) Finally, a small amount of water is removed by a screw extrusion conveyor to obtain 4.4m mud blocks with the water content of 72.7 percent 3 /H。
Example 2
A system for in situ dewatering of a slurry is shown in figure 1.
a) Will be 60m 3 The dredging slurry with 96.0% water content of/H enters a screening device to screen out residues which may block or damage pipeline equipment, the slurry flows into a stirring tank and is added with flocculating agent polyferric chloride, the flocculating agent and the slurry are uniformly mixed by the stirring device and are subjected to flocculation reaction, and overflow water is discharged for 12m 3 H, the water content of the slurry concentrated at the bottom reaches 95.0%;
b)48m 3 lifting/H concentrated slurry by a pump, adding polyacrylamide solution, mixing, feeding into a slurry dewatering device, and overflowing water for 30m in the rotating process 3 A small part of overflow water returns to the dispensing tank for conditioning and thickening agents, and mud clusters enter a mud-water separation device;
c) In the mud-water separation device, a rotary screen drum screens out water wrapped in mud clusters to obtain mud clusters 9.6m with water content of 75.0% 3 /H。
d) Finally, a small amount of water is removed by a screw extrusion conveyor to obtain 8.7m mud blocks with water content of 72.4 percent 3 /H。
Example 3
A system for in situ dewatering of a slurry is shown in figure 1.
a) Will be 60m 3 The dredging slurry with 94.0% of water content of/H enters a screening device to screen out residues which may block or damage pipeline equipment, the slurry flows into a stirring tank and is added with flocculating agent polyferric chloride, the flocculating agent and the slurry are uniformly mixed by the stirring device and are subjected to flocculation reaction, and overflow water is discharged for 4m 3 H, the water content of the slurry concentrated at the bottom reaches 93.6%;
b)56m 3 lifting/H concentrated slurry by a pump, adding solution of polysaccharide, mixing, feeding into a slurry dewatering device, and overflowing water for 35m in the rotating process 3 A small part of overflow water returns to the dispensing tank for conditioning and thickening agents, and mud clusters enter a mud-water separation device;
c) In the mud-water separation device, the water and the water are separated,the water wrapped in the mud ball is removed by a rotary screen drum, and the mud ball with water content of 74.3% is obtained by 14m 3 /H。
d) Finally, a small amount of water is removed by a screw extrusion conveyor to obtain 13m mud blocks with water content of 72.3% 3 /H。
In step a) of the above embodiments, the screen device uses a vibration classifying screen, and the screened slag includes crushed plastic pieces, crushed fibers, small stones, small bricks, cement blocks and the like; the overflow water is influenced by unstable inflow and solid content of dredging slurry, the mentioned flow is rated treatment capacity of a specific system, the average flow is 8 hours, and the mentioned slurry water content is average value in 8 hours.
In the step b) of each embodiment, the recovery amount of the overflow water is set according to the demand amount of the dispensing tank, and the components of the slurry substance are required to be matched with the specific variety and the addition amount of the conditioning agent, and are usually determined specifically through a compatibility test.
In the above examples, in step d), the water content of the finally obtained dehydrated cake is related to the organic matter content of the raw slurry, and the lower the organic matter content is, the lower the water content of the obtained dehydrated cake is.
The system of the invention realizes the on-site rapid dehydration of slurry, and compared with the conventional plate-frame filtering treatment system with the same installed power, the system has the treatment speed of more than 5 times (more than 2.5 times relative to a spiral shell dehydrator), and the occupied area is only 50 percent of that of the conventional plate-frame filtering treatment method, thus obtaining better technical effect.