RU2434098C1 - Procedure for basin bottom anti-filter screening - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: water-colloidal suspension is prepared of micro-dispersed mud. It is supplied to a specified point through flexible pipeline (12). Further, specified amount of suspension is discharged through long-length tube to bottom (8) of basin (7). Long-length tube in its middle part (13) is conjugated with flexible pipeline (12) by means of inlet branch (14) through collar (37). Long-length tube (13) is equipped with discharge nozzles (15) and with plates (16) bent on ends. Discharge nozzles (15) are arranged along length of long-length tube (13). Plates (16) on ends of long-length tube (13) facilitate its sliding along bottom (8) of basin (7). Pressure level in flexible pipeline (12) ensures generation of specified force actuating transfer of long-length tube (13) in the direction of its motion along bottom (8) of basin (7) as well, as washout and stirring-up sediments (6) with jets of suspension (28). Washed out layer (36) of sediments is mixed with suspension of jets in specified volumes. In the process of settling these volumes form anti-filtration screen (29) on a strip of the basin bottom treated in such way.

EFFECT: reduced time for forming screen, raised uniformity of mud distribution in screen and of density of sediments in screen.

5 cl, 4 dwg

Description

The invention relates to hydraulic engineering construction and can be used in anti-filtering shielding in the area of increased filtration of the bottom of a reservoir at industrial waste dumps, ponds for various purposes, sewage treatment plants and other structures without shutting down and emptying them.

A known method of antifiltration screening of the bottom of the reservoir, which provides for pouring a layer of cohesive soil onto the surface of the ice cover in the peripheral zone of the reservoir cooler, moving the water of the ice cover together with the cohesive soil in parts in the form of ice maps to the intended non-freezing zone of increased filtration of the reservoir and destruction of ice maps in a natural or artificial way. As a result, the bottom of the reservoir in the designated zone of the reservoir is shielded by cohesive soil, and the ice intensively cools the water during melting [1].

The disadvantage of this method is as follows:

- the area of use is limited mainly to cooling reservoirs;

- insufficient shielding due to uneven stacking and increased friability of cohesive soil;

- high costs due to the use of a large number of cohesive soil and the complexity of the work;

- cohesive soil reduces reservoir capacity.

From the source [2] it is known that in 2004, under the conditions of permafrost, the intensive filtration of water through the coastal part of the reservoir was eliminated by creating an anti-filter screen using a polymer film in the Sytykan waterworks hydropower plant. At the same time, a film cloth with an area of 6000 m ^{2 was} laid on the bottom of the reservoir in winter by establishing a cloth through the lane using cables under the ice.

The disadvantage of this known method is the complexity of the work.

A known method of antifiltration shielding in the area of increased filtration of the bottom of a sludge pond of a liquid waste accumulator, according to which a water-colloidal suspension is prepared from a micro-dispersed colmatant, which is released together with a tail (slurry) pulp. When water moves from the place where the pulp is discharged to the water intake, the waste is deposited together with the Kolmatant to the bottom of the settling pond. As microdispersed colmatant, ultrafine (less than 0.1 μm) oxides of silicon, calcium and aluminum are used, the specific surface area of which is not less than 40 m ² / g [3].

The method is simple to implement. However, the effectiveness of the shielding method is small due to the uneven distribution of the Kolmatant over the area and thickness of the created screen and fractionation of the grain composition of the Kolmatant in the process of washing the waste, which reduces the quality of the screen and leads to unproductive expenditure of the Kolmatant.

The closest in technical essence and the achieved result to the proposed invention is a method of antifiltration shielding in the zone of increased filtration of the bottom of the reservoir, according to which a micro-dispersed colmatant is used to prepare a water-colloidal suspension, which is fed under pressure to the intended place and the suspension is discharged from the surface of the reservoir to its bottom in a given quantity. The suspension is discharged to the bottom of the reservoir in the cold season through the wells, which are carried out in ice at a distance of 5-15 m from one another, and in the warm season, by means of a floating flexible pipeline moving along the open surface of the reservoir [3].

The disadvantage of this known method is as follows:

- a long period of time the formation of the screen layer (hereinafter referred to as the screen), since time is needed to cover the suspension with “fresh” deposits, therefore the colmatant is unproductively scattered in a large volume of deposits during this time, i.e. in an excessively thick and slightly condensed screen;

- high non-uniformity of the distribution of the suspension along the bottom of the reservoir, which leads to uneven distribution of colmatant in the filter screen, the unevenness of the thickness of the screen and its discontinuity;

- low density of deposits in the screen, which reduces the anti-filter properties of the screen due to the high water permeability of deposits in the screen, and due to the poor implementation of the anti-filtration properties of unmatched deposits by the co-matting agent.

Indeed, as long as the suspension is located on the bottom surface, the involvement of the colmatant by the filtration stream in the deposits will be difficult. Therefore, the creation of the screen is slow, and the colmatant during this time is unevenly scattered in the thick screen. This does not ensure the occurrence of high filtration gradients within the resulting screen, and consequently, the high filtration forces necessary for force compaction in the sediment screen. All this reduces the effectiveness of anti-filter shielding.

The problem to which the invention is directed, is to increase the effectiveness of impervious shielding. The technical result achieved in this case is to accelerate the creation of the screen, to increase the uniformity of the distribution of colmatant in the screen and to increase the density of deposits in the screen.

This problem is solved, and the technical result is achieved by the fact that in the method of anti-filtration screening of the bottom of a reservoir, including the preparation of a micro-dispersed colmatant of a water-colloidal suspension, feeding the suspension through a flexible pipe under pressure to the place of release of the suspension to the bottom of the reservoir in a predetermined quantity, according to the invention, the release of the suspension produced through a tubular length meter. This tubular length meter through the inlet pipe is interfaced with the middle part of the flexible pipe and is equipped with exhaust nozzles located along the length of the tubular length meter in one plane and bent at the ends of the plates located on the ends of the tubular length meter in another plane and allowing the tubular length meter to slide along the bottom of the reservoir. In the cross section of the tubular length meter, the outlet nozzles form an acute angle with the inlet pipe, and a plane drawn through the top of this acute angle and parallel to the plane of the plates divides the acute angle into two parts. The flexible pipeline is equipped with a means for adjoining the flexible pipeline coaxially to the inlet pipe, and a means for controlling the direction and speed of movement of the tubular length meter along the bottom of the reservoir along a given strip. The pressure in the flexible conduit ensures the creation of a predetermined magnitude of force acting on the tubular length meter in the direction of its movement along the bottom of the reservoir, erosion and agitation by the jets of the suspension of sediments and mixing them with a suspension of jets in predetermined volumes. These volumes provide the formation in the process of sedimentation of an anti-filter screen on the thus treated strip of the bottom of the reservoir.

Additionally:

- ultrafine (less than 0.1 μm) oxides of silicon, calcium and aluminum, the specific surface area of which is not less than 40 m ² / g, are used as microdispersed colmatant;

- each end of the tubular length is equipped with an exhaust nozzle;

- the suspension is fed through a flexible pipe under a pressure of at least 0.5 MPa;

- the conditions are satisfied:

d _{te rm} and ≥2d

d _rm ≥2nd _about,

Where

d _te - the inner diameter of the tubular length meter;

d _gt - the inner diameter of the flexible pipe;

n is the number of exhaust nozzles in a tubular length meter, pcs .;

d _about - given the cross-sectional area of the diameter of the outlet of the exhaust nozzle.

Figure 1 shows a bulk drive with a filter-hazardous section of the bottom, plan; figure 2 - arrangement of equipment during shielding, plan; figure 3 is a section aa in figure 2; figure 4 is a section bB in figure 2.

Example. The capacity of the floodplain bulk accumulator (hereinafter referred to as the accumulator) 1 is created on three sides by a dirt dam 2, and on the fourth side by a terrace 3. Fine industrial waste is fed into the accumulator 1 in the form of pulp from the side of terrace 3 along the pulp line 4 with outlets 5. The peculiarity of the accumulator is the fact that it occupies a relatively small area, about 10-15 hectares. Therefore, solid waste particles settle and form deposits 6 without the formation of a surface beach, and clarified water forms a reservoir 7, the surface of which is open in the warm season.

During the operation of the reservoir 1 it was found that due to stricter environmental requirements, the amount of filtration from the reservoir 1 of polluted water towards the river (the river is not shown), i.e. in the opposite terrace 3 side exceeded the permissible value. Therefore, it was decided to impervious shielding relative to the horizontal bottom 8 of the reservoir 7 in the filtration-hazardous section 9 adjacent to the dam 2.

Shielding is carried out in the warm season. First, using a known technology and using known means [3 and 4], a water-colloidal suspension is prepared from a micro-dispersed colmatant on a suspension unit (unit not shown). As microdispersed colmatant, ultrafine (less than 0.1 μm) oxides of silicon, calcium and aluminum are usually used, the specific surface area of which is usually not less than 40 m ² / g. Then this suspension, for example, on a fire truck 10 along the ridge 11 of the dam 2, is delivered to the hazardous filtration section 9, through a flexible pipe 12, the suspension is supplied under pressure to the intended place and through the tubular length meter (hereinafter referred to as the pipe) 13 the suspension is released from the flexible pipe 12 to the bottom 8 of the reservoir 7.

This pipe 13 through the inlet pipe 14 is interfaced with the middle part of the flexible pipe 12 and is equipped with exhaust nozzles 15 located along the length of the pipe 13 in one plane and bent at the ends of the plates 16 located on the ends of the pipe 13 in another plane. In the cross section of the pipe 13, the outlet nozzles 15 form an acute angle α with the inlet 14, and a plane drawn through the top of this acute angle α and parallel to the plane of the plates 16 divides the acute angle α into two parts. In this case, the pipe 13 is connected to the pontoon 17 by means of two rigid connections 18 and four flat joints 19 at their ends.

The channel shape in the output nozzle 15 is flattened and expanded in plan, which increases the uniformity of erosion of deposits 6.

On the ridge 11 of the dam 2, on the continuation of the longitudinal axis 20, intended for processing by suspension of the strip 21 of the bottom 8 of the reservoir 7, a concrete slab 22 is installed. A wheel 24 is mounted on the vertical axis 23 attached to the slab 22, equipped with a circumferential groove for flexible conduit 12 and adjacent to it friction elements (gutter and friction elements not shown). Such a wheel 24 directs the movement of the flexible pipe 12 along the longitudinal axis 20 of the strip 21. This provides a coaxial abutment of the flexible pipe 12 to the inlet pipe 14 on the pipe 13, which prevents torsion of the flexible pipe 12 and the transmission of this torsion to the pipe 13. On the same plate 22 set a winch 25 with a manual drive, the rope 26 of which is fastened with a flexible conduit 12 and secured to the pontoon 17. By means of such a winch 25, a pontoon 17, an escort boat 27 and other manual means, for example poles, provide direction control and the speed of movement of the pipe 13 to the bottom 8 of the reservoir 7 along a given strip 18.

The pressure p in the flexible pipe 12 usually create at least 0.5 MPa. This pressure provides the creation of a predetermined force F acting on the pipe 13 in the direction of its movement along the bottom 8 of the reservoir 7, washing out and stirring up the suspension of sediments 6 by the jets 28 and mixing them with the suspension of the jets 28 in the given volumes.

The suspension at the exit of the nozzles 15 moves towards the suspension moving along the flexible pipe 12, i.e. with a rotation close to 180 °. Therefore, the effect of the suspension on the pipe 12 can be approximately considered as the pressure of the jet on a curved solid plate, and the force F can be approximately determined by the formula known from the hydraulic course [5]. Moreover, in accordance with the magnitude of the force F and the force necessary to slide the pipe 13 along the bottom 8, the negative buoyancy of the pipe 13 can be technically changed.

Mixing volumes are assigned from the conditions of formation during the sludge process on the thus treated strip 21 of the screen 29 with a thickness of 5-8 cm (figure 3). These mixing volumes are set and calculated in the project depending on local conditions. In this case, one volume of suspension usually accounts for from 3 to 6 volumes of sediment 6, and the concentration of colmatant in the suspension, based on practice, can be taken 2-4% [3 and 4]. Moreover, the formation of the screen 29 occurs with a uniform distribution in the screen 29 of the Kolmatant, and without its grain fractionation.

The slurry jets emerging from the end nozzles 30 prevent tearing in the screen 29 between the strips 21, the width of which is usually equal to the length of the pipe 13, and the plates 16 provide directional sliding of the pipe 13 along the bottom 8.

The dimensions of the cross sections of the elements forming the suspension path, are assigned from hydraulic conditions and can be previously characterized by the ratios:

d _{te rm} and ≥2d

d _rm ≥2nd _about,

where d _te - the inner diameter of the tubular length meter;

d _gt - the inner diameter of the flexible pipe;

n is the number of exhaust nozzles in a tubular length meter, pcs .;

d _about - given the cross-sectional area of the diameter of the outlet of the exhaust nozzle.

Processing the suspension of the bottom 8 is carried out by feeding the fire truck 10 suspension under pressure according to the scheme "from the dam". The force F arising due to the operation of the pump on the fire engine 10 moves the pipe 13 together with the flexible pipe 12 in the direction of the fixed pole 31 installed outside the section 9 along the axis 20 of the strip 21. The speed of the pipe 13 is regulated by braking by the winch 25 of the pontoon 17, and when necessary by increasing the speed of the pipe 13 through the escort boat and other manual means - poles. As the flexible conduit 12 enters the reservoir 7, it, together with the rope 26, is equipped with floats, which are usually made in the form of chamber tires 32 with cords 33 (Fig. 4).

The return of the pipe 13 to the dam 2 is carried out by means of a winch 25 in the absence of pressure in the flexible pipe 12 and with the raised pipe 13 above the waste 6 (lifting means not shown). In this case, the flexible conduit is freed from the chamber tires 32 and the rope 26 and placed on the crest 11 of the dam 2. After that, the concrete slab 22 together with the wheel 24 and the winch 25 are installed on the longitudinal axis 20 of the next strip 21.

In the drawings, other elements of the drive and method are indicated, namely:

34 - road, 35 - ditch, 36 - washable layer (deposits), 37 - cuff, l - strip length, δ - screen thickness.

In modern high-performance hydraulic monitors designed to destroy and flush rocks, the pressure in the barrel reaches 12 MPa. We believe that for the erosion and agitation of unhardened or weakly hardened deposits, the pressure of 1.0 MPa of the suspension in flexible conduit 12 can be considered preliminary as the limiting one, and the pressure of 0.5 MPa as sufficient.

A feature of the operation of the thus created thin and almost continuous screen 30 is as follows:

1. The screen almost immediately exhibits antifiltration properties, as a result of which in such a thin screen the filtration gradients I increase, which can quickly reach the value I = (H + δ) / δ, where H is the height of the water layer above the screen.

These high filtration gradients cause high filtration forces, which compact the screen material and thereby reduce its permeability, as well as prevent further unproductive dispersion of the mud over the screen.

2. As the waste is further stored, the water level in the drive increases, therefore, the filtration gradients I, therefore, and the density of the waste in the screen increase, and the quality of the screen also increases.

Other modifications and changes may be made to the present invention without departing from the scope of the invention. For example, you can avoid the formation of a loop from the flexible pipe 12 (figure 2) by placing the flexible pipe 12 on the other side of the wheel 24 and slow movement back and forth, respectively, of the fire engine 10. In this case, you can do without a winch 25 and a rope 26.

The capabilities of modern industry make it possible to obtain silicon dioxide with a specific surface area of 300-1000 m ² / g and form microgels based on them, which are used in the paper and pulp industry [6]. Under certain conditions, such gels can also find application in enhancing the waterproofing of water bodies for various purposes.

Information sources

1. Patent of the Russian Federation No. 2005841, cl. E02B 3/16, publ. 01/15/1994.

2. Patent of the Russian Federation No. 2267576, cl. E02B 3/00, publ. 01/10/2006.

3. Zubchenko G.V. Express method of enhancing the waterproofing of existing treatment facilities. // Non-ferrous metals. 2009. No7.

4. Zubchenko G.V. Strengthening the waterproofing of treatment facilities without shutting down and disrupting the operation. // Metallurgist. 2005. No5.

5. Handbook of hydraulic calculations. Ed. P.G. Kiseleva. Ed. 5th. M., Energy, 1974. P.28.

6. Patent of the Russian Federation No. 2363656, cl. C01B 33/143, publ. 08/10/2009.

Claims (5)

1. A method of antifiltration screening of the bottom of a reservoir, including the preparation of a micro-dispersed colmatant of a water-colloidal suspension, feeding the suspension through a flexible pipe under pressure to the place of release of the suspension to the bottom of the reservoir in a predetermined amount, characterized in that the suspension is discharged through a tubular length meter, which is through an inlet the nozzle is interfaced with the middle part with a flexible pipe and is equipped with exhaust nozzles located along the length of the tubular length meter in the same plane and bent to to the ends with plates located at the ends of the tubular length meter in a different plane and allowing the tubular length meter to slide along the bottom of the reservoir, and in the cross section of the tubular length meter the outlet nozzles form an acute angle with the inlet pipe, and the plane drawn through the top of this acute angle and parallel to the plane of the plates divides an acute angle into two parts, while the flexible pipe is equipped with a means for adjoining the flexible pipe coaxially to the inlet pipe, and a means for controlling the direction and speed of movement of the tubular length meter along the bottom of the reservoir along a given strip, and the pressure in the flexible pipe ensures the creation of a predetermined magnitude of force acting on the tubular range finder in the direction of its movement along the bottom of the reservoir, washing and stirring sediment with jets of the suspension and mixing them with the suspension jets in the volumes necessary for the formation of an anti-filtration screen in the process of sedimentation on the thus treated strip of the bottom of the reservoir. 2. The method according to claim 1, characterized in that ultrafine (less than 0.1 μm) oxides of silicon, calcium and aluminum, the specific surface area of which is not less than 40 m ² / g, are used as microdispersed colmatant. 3. The method according to claim 1, characterized in that each end of the tubular element is equipped with an exhaust nozzle. 4. The method according to claim 1, characterized in that the suspension is fed through a flexible pipe under a pressure of at least 0.5 MPa. 5. The method according to claim 1, characterized in that the conditions are satisfied:
d _{te rm} and ≥2d
d _gt > 2nd _o ,
where d _te - the inner diameter of the tubular length meter;
d _gt - the inner diameter of the flexible pipe;
n is the number of exhaust nozzles in a tubular length meter, pcs .;
d _o - given the cross-sectional area of the diameter of the outlet of the exhaust nozzle.

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