CN111330731A

CN111330731A - Sorting device and sorting process for wet-method sorting of petroleum fracturing sand

Info

Publication number: CN111330731A
Application number: CN202010368375.9A
Authority: CN
Inventors: 李继余; 刘建华; 王海会; 张超
Original assignee: Tongliao Silica Sand In Building Materials Industry Co ltd
Current assignee: Tongliao Silica Sand In Building Materials Industry Co ltd
Priority date: 2020-04-30
Filing date: 2020-04-30
Publication date: 2020-06-26
Anticipated expiration: 2040-04-30
Also published as: CN111330731B

Abstract

The invention relates to the technical field of wet-method solid-solid separation equipment and methods, in particular to a separation device and a separation process for separating petroleum fracturing sand by a wet method. The conventional hydraulic classifier has poor classification effect, serious thickness mixing in classification products and low granularity concentration rate. The sorting device comprises a feeding system, a pretreatment system, a primary sorting system and a secondary sorting system, wherein the pretreatment system is used for dehydrating, concentrating, removing impurities, wiping and lifting the mortar; the primary and secondary sorting systems are provided with two sets of parallel classifiers. According to the invention, silica sand with different specifications is rapidly screened at one time by one set of production line, so that the screening efficiency of hydraulic classification of the silica sand is greatly improved; the circular arc-shaped water filtering net can also maximize the contact area, distribute more water filtering holes and construct a more stable mobile phase.

Description

Sorting device and sorting process for wet-method sorting of petroleum fracturing sand

Technical Field

The invention relates to the technical field of wet-method solid-solid separation equipment and methods, in particular to a separation device and a separation process for separating petroleum fracturing sand by a wet method.

Background

Silica sand (quartz sand) has found widespread use in the glass, foundry and other industrial sectors in recent years, but it is generally classified or deslimed prior to use. Quartz sand is an important industrial mineral raw material and is widely applied to the industrial fields of glass, casting, metallurgy, chemical industry, grinding materials and the like. Most of the quartz sand is produced by crushing quartz rock ores and grading, and a sand source can be directly mined in areas with abundant natural sand resources. The production process of the quartz sand comprises a wet production process and a dry production process. The quartz sand used as the glass raw material is mainly produced by a wet process. The wet process production has the following advantages: the production rate is high; the material grading and conveying are convenient; preventing the flying of dust in the production process, environmental pollution and harm to human body. Under the conditions of continuous enlargement of the production scale of quartz sand and great improvement of yield, the requirement on quality is stricter, and the particle size classification in the production process is a key process. The classification method and the classification machine have great influence on the investment cost, the product quality, the operation cost and the like of the quartz sand production device. Therefore, the deep research on the grading mechanical equipment in the quartz sand production has very important practical significance for improving the product quality and reducing the production cost. Silica sand for glass needs to be removed with +0.8 mm coarse particles and-0. l milli-fine fraction; before the foundry sand is sold to users, various specifications such as 45/75 meshes, 55/100 meshes, 75/150 meshes, 100/200 meshes and the like need to be sorted in a concentrating mill, and the granularity concentration rate (precision) of each grade of silica sand is required to be more than 75-80%. Therefore, the quality of the silica sand grading effect directly influences the product quality.

Currently, there are two main domestic silica sand classification methods: one is classification by using a sieve (flat shaking sieve, high square sieve, drum sieve, vibrating sieve, etc.), and the other is classification by using hydraulic power (including desliming). When the silica sand with the granularity of 0.1-1 mm (particularly thinner) is screened and sorted, the screen is easy to block, the grading efficiency is not high, and the screen is seriously abraded. In China, a lot of silica sand sorting plants adopt hydraulic classification, and a desliming bucket or a conical (or cylindrical) hydraulic classifier with ascending water flow improved by the desliming bucket is mainly used for desliming or classification. The hydraulic classification equipment has no moving parts, can not be abraded, and can meet the requirements of various industrial departments (especially glass industry) on the granularity of silica sand to a certain extent; however, for the departments with strict requirements on the granularity (such as precision casting), the quality is sometimes difficult to ensure, and the spiral classifier and the hydrocyclone are only adopted by individual silica sand concentrating mills. The granularity of the spiral grading overflow is not easy to control, and rotating parts are easy to wear; hydrocyclones are sensitive to operating conditions such as water pressure and feed.

Most of the foundry sand production enterprises in China adopt a series of conical hydraulic classifiers (including a cylindrical hydraulic classifier with a smaller lower cone and a cylinder with a certain height at the upper part) to carry out continuous desliming-grading operation on natural silica sand through a washing tower. Although the classifier has simple structure, low manufacturing cost and convenient operation, when the classifier is used for classifying coarse particles (0.3-1 mm), due to the limitation of the structure, the classification effect is poor, the coarse and fine mixed in classified products is serious, the particle size concentration rate is low, and unqualified products are easy to appear.

In foreign countries, silica sand classification also mainly adopts screening and hydraulic classification. The natural sand desliming generally takes a cyclone as a main part, and when the raw sand contains few impurities, the main operation of mineral separation is classification. In order to improve the grading effect and improve the grading efficiency, many foreign companies pay attention to research and develop high-efficiency grading equipment, such as arc screens, jet classifiers, siphon classifiers and various ascending water flow classifiers. Among them, the ones with better grading effect are automatic interference settlement grader, Rheax type grader, etc. The Rhemax fractionation method is widely used in Australian, Fin, Sweden, Olympic, Germany, Japan, etc., because of its high fractionation accuracy.

Silica sand is widely applied, the requirements on the granularity (mesh number and particle size) of the sand are different in different application occasions, the requirement on the granularity concentration rate of each mark of silica sand is different, and particularly in the process of large-scale mass production, the requirement on the quantity is possibly greater than the requirement on the precision. Therefore, how to realize the production requirement of sorting various specifications and various particle size precisions by using a set of equipment (production line) is a technical problem mainly solved by the invention. Of course, the above-mentioned equipment is not necessarily required to meet both the requirements of specification and precision, and it is also possible to achieve the above-mentioned requirements by designing and improving the process method.

In the process of separating sand by a hydraulic classification method, firstly, the sand in a water separation device is divided into 3 types, namely a floating layer, a suspended layer and a sinking layer, which occupy an upper layer, a middle layer and a lower layer in a separation container. In actual production, hydraulic classification is carried out in a hindered settling tank, and due to the characteristics of hydraulic classification, the requirements on classification precision and productivity are met, high dispersion degree among particle sizes is required, and the section size of certain equipment is ensured. From theoretical analysis, under the condition of a certain water flow velocity, the circulating water quantity is in direct proportion to the square of the diameter of the equipment, the larger the treatment capacity of the equipment is, the higher the grading precision is, the larger the section size of the required equipment is, and the larger the circulating water quantity and the power consumption corresponding to the section size are. Therefore, the diameter of the hindered settling tank is designed to be reduced as much as possible, and the problem of dispersion among particle sizes and productivity is solved by increasing the height of equipment, wherein the height of the hindered settling tank is more than 3 m. Due to the structural characteristics of the hindered settling tank, the equipment investment cost is high and the building capital cost of a factory is high compared with screening and grading under the condition of the same grading treatment capacity.

The hydraulic classification has the advantages that: the hydraulic classification is to separate particles with different particle sizes through the buoyancy of water flow, compared with a screening method, the hydraulic classification has no screen in equipment, the screen does not need to be replaced, the maintenance cost of the equipment is reduced, the labor intensity of workers and the auxiliary time of production are reduced, and meanwhile, the continuity and the stability of production are ensured. The disadvantages are that: the hydraulic classification is to separate particles with different particle sizes according to the characteristics of water flow, so that the density, shape and sedimentation conditions of the particles have influence on the sedimentation velocity, and the cross-sectional size of equipment is limited by factors such as power consumption in design, so that the particle group mixing phenomenon is serious during classification, and the problems of high power consumption, low separation precision, low unit volume processing capacity and the like exist. In addition, the hydraulic classification operation control is strict, and the control process is easy to fluctuate. When all the control factors change in the production process, the classification is easy to fail.

Therefore, as can be seen from the above description, the state of the dispersion formed between the water and the sand in the sorting device has a significant influence on the sorting effect, i.e., a uniform and stable dispersion can output sand with a single particle size (a certain mesh range) to a certain extent, and the precision of the sorted product (the proportion of sand with a specified particle size in sand of a certain specification) is high. However, in the currently known sorting device, the mortar feeding pipe and the water feeding pipe in the single classifier (referring to the barrel body of a single sorting device) have no matching relationship, so that the fed mortar continuously destroys the dispersion system balance established and maintained in the barrel body, and the classification effect is influenced.

The petroleum fracturing sand belongs to a fracturing propping agent, has high fracturing strength, and is mainly used for underground support of an oil field so as to increase the yield of petroleum and natural gas. The fracturing propping agent is prepared by sintering various raw materials such as high-quality bauxite and the like by using ceramics, is a substitute of medium and low strength propping agents such as natural quartz sand, glass balls, metal balls and the like, and has good effect on increasing the yield of petroleum and natural gas. When the petroleum and natural gas deep well is exploited, the high-closure-pressure low-permeability deposit is fractured to crack the oil-gas-containing rock stratum, and the oil gas is collected from a channel formed by the fracture. The ceramsite supporting material enters the stratum along with the high-pressure solution and is filled in the cracks of the rock stratum, and the effect of supporting the cracks not to be closed due to stress release is achieved, so that the high flow conductivity is kept, oil and gas are smooth, and the yield is increased. Practice proves that the oil well fractured by the ceramsite proppant can improve the yield by 30-50% and can prolong the service life of the oil and gas well.

The fracturing propping agent can be widely used for the fracturing reformation of deep wells and high-pressure oil-gas layers. Classification of fracturing proppant products:

1. according to the crushing resistance degree, respectively: four series of 52MPa (7500 psi), 69MPa (10000 psi) and 86MPa (12500 psi), 102MPa (15000 psi);

2. the volume density is divided into: low, medium, high density;

3. according to the specification, the method comprises the following steps: 12-20 meshes, 16-30 meshes, 20-40 meshes, 30-50 meshes, 40-60 meshes, 40-70 meshes, 70-100 meshes and the like. In order to meet the requirements of oil and gas wells at home and abroad, users can select products with different strengths and specifications according to the depth of the oil well. Of course, the product classification is based on standard fracturing propping agents, and indexes such as classification specification and crushing strength are different when natural silica sand is used as the fracturing propping agent.

Silica sand resources in northern China are abundant, and the silica sand can be widely used for hydraulic classification operation, wherein the sand collecting device is generally a sand collecting ship, a sand collecting pump and the like, and for example, documents such as a multi-purpose sand collecting ship in the Chinese patent CN106492975B, a double-side sand collecting ship in the CN203753299U, a CN203583545U, a water flushing sand collecting ship and the like all disclose the sand collecting device and/or the sand collecting method.

Disclosure of Invention

The invention mainly aims to: a set of hydraulic classification device is provided, namely a production line for performing hydraulic classification on silica sand with various specifications by adopting the set of hydraulic classification device.

Another object of the invention is mainly: provides a set of production process and method for hydraulic classification by adopting the hydraulic classification device.

The above purpose is realized by the following technical scheme:

[ A ] to

The utility model provides a sorting unit for wet process is selected separately oil fracturing sand which characterized in that:

the sorting device comprises a feeding system, a pretreatment system, a primary sorting system and a secondary sorting system, wherein the feeding system is used for continuously supplying mortar raw materials to the sorting device from a mortar source place, the pretreatment system is used for carrying out operations including but not limited to dehydration, concentration, impurity removal, wiping and lifting on the mortar raw materials supplied by the feeding system, the primary sorting system is used for carrying out coarse product sorting on the mortar processed by the pretreatment system, and the secondary sorting system is used for carrying out fine product sorting on the mortar sorted by the primary sorting system;

the feeding system comprises a sand extraction ship, the sand extraction ship is provided with a conveying pipeline, the conveying pipeline is connected with the pretreatment system, and mortar collected by the sand extraction ship is supplied to the pretreatment system through the conveying pipeline;

the pretreatment system comprises a first cyclone, a first impurity sieve, a zero classifier, a first scrubbing machine, a first hoister, a second cyclone and a second impurity sieve;

the first cyclone is used for dehydrating and concentrating the mortar;

the first impurity screen is used for removing impurities except water, sand and mud in the mortar;

the zero classifier is used for concentrating, dehydrating and desliming the mortar;

the first scrubbing machine is used for scrubbing mortar;

the first lifting machine is used for lifting the mortar to a high place;

the second cyclone is used for dehydrating and concentrating the mortar;

the second impurity screen is used for removing impurities except water and sand in the mortar;

the primary sorting system comprises four primary classifiers which are respectively a primary classifier, a secondary classifier, a tertiary classifier and a quartering classifier;

the primary sorting system comprises two primary finished product pools, namely a first finished product pool and a second finished product pool;

the primary classifier is in a barrel shape and is provided with a sand supply pipe, a water inlet pipe, an overflow trough and a discharge port; the water inlet pipe is arranged at the bottom of the primary classifier and is used for supplying water to the primary classifier; the sand supply pipe is arranged above or at the side part of the primary classifier and is used for supplying mortar to the primary classifier; the overflow groove is arranged on the outer side of the upper edge of the barrel wall of the primary classifier and is used for receiving the materials overflowed from the upper edge of the primary classifier; the discharge port is arranged at the bottom of the primary classifier;

the discharge port of the first sub-machine is connected with the sand supply pipe of the second sub-machine, and the overflow trough of the first sub-machine is connected with the sand supply pipe of the third sub-machine;

the discharge port of the second branch machine is connected with the first finished product pool, and the overflow groove of the second branch machine is connected with the second finished product pool;

the discharge ports of the three-branch machine are connected with the sand supply pipes of the four-branch machine, and overflow chutes of the three-branch machine are connected to a secondary sorting system through pipelines;

the discharge ports of the four sub-machines are connected with the second finished product pool, and overflow chutes of the four sub-machines are connected to the secondary sorting system through pipelines;

the secondary sorting system comprises two secondary classifiers which are respectively a five-branch classifier and a six-branch classifier;

the secondary sorting system comprises two secondary finished product pools, namely a third finished product pool and a fourth finished product pool;

the secondary classifier adopts the same structure as the primary classifier;

the overflow chutes of the three-branch machine and the four-branch machine are connected with the sand supply pipes of the five-branch machine through pipeline confluence;

the discharge ports of the five-branch machine are connected with the sand supply pipes of the six-branch machine, and overflow chutes of the five-branch machine are emptied through pipelines extending outwards;

the discharge port of the six-branch machine is connected with the third finished product pool, and the overflow groove of the six-branch machine is connected with the fourth finished product pool.

The sand extraction ship, the first cyclone, the first impurity sieve, the zero classifier, the first scrubbing machine, the first hoister, the second cyclone, the second impurity sieve and the sorter are sequentially connected;

and a water pump is arranged between the sand extraction ship and the first cyclone, and is used for pumping mortar to the first cyclone by the sand extraction ship.

The first cyclone, the first impurity screen, the zero classifier and the first scrubbing machine convey mortar from top to bottom through gravity;

the second impurity sieve is connected with a sand supply pipe of the separator;

the second cyclone, the second impurity screen, the first separator, the second separator, the third separator and the fourth separator convey mortar from top to bottom through gravity;

the mortar is conveyed from top to bottom among the three-branch machine, the four-man machine and the five-branch machine and among the five-branch machine and the six-branch machine through gravity;

the water inlet pipes of the primary classifier and the secondary classifier are respectively connected with an external water source.

A secondary treatment system is arranged between the primary sorting system and the secondary sorting system;

the secondary treatment system comprises a concentration tank, a stabilized ore classifier, a second scrubbing machine, a second hoister and a third swirler;

the concentration tank is funnel-shaped, overflow groove confluence mortar output pipelines of a third sub-machine and a fourth sub-machine in the primary separation system are connected above the concentration tank, and a stabilized ore classifier is connected below the concentration tank;

the stabilized ore classifier adopts the same structure as the primary classifier, the overflow groove of the stabilized ore classifier is emptied outwards through a pipeline, and the discharge port is connected with a second scrubbing machine;

the second scrubbing machine has the same structure as the first scrubbing machine, the size specification of the second scrubbing machine is smaller than that of the first scrubbing machine, and the outlet of the second scrubbing machine is connected with a second hoisting machine;

the second hoister adopts the same structure as the first hoister, lifts the mortar to a high place and is connected into the third swirler;

the third cyclone adopts the same structure as the second cyclone, and the outlet of the third cyclone is connected with five sand supply pipes.

The primary classifier comprises a barrel body, a conical or bowl-shaped bottom sieve part is arranged in the barrel body, the bottom sieve part is inverted at the bottom of the barrel, the upper edge of the bottom sieve part is connected with the side wall of the primary classifier barrel, the bottom of the bottom sieve part is abutted to the middle position of the bottom surface of the primary classifier barrel, and a discharge port of the bottom surface of the primary classifier barrel is communicated with the bottom of the bottom sieve part.

The zero classifier adopts the same structure as the primary classifier;

the zero classifier is provided with a sand feeding pipe, a water inlet pipe, an overflow groove and a discharge port, the sand feeding pipe of the zero classifier is connected with the first impurity sieve, the water inlet pipe of the zero classifier is connected with an external water source, the overflow groove of the zero classifier is emptied through a pipeline extending outwards, and the discharge port of the zero classifier is connected with the first scrubbing machine.

[ II ] A

The primary sorting system is provided with two sets of parallel primary classifiers, and the primary classifier, the secondary classifier, the tertiary classifier and the quartering classifier are respectively provided with two sets;

a first distributor is arranged between the two first extension machines and the second impurity sieve, the first distributor has a three-way structure, a mixing cavity is arranged at the intersection of the three-way structure, and the mixing cavity is used for uniformly mixing mortar entering the two first extension machines from the first impurity sieve;

the discharge ports of the two secondary separating machines share the first finished product pool, the overflow ports share the second finished product pool, and the discharge ports of the two four separating machines share the second finished product pool.

The secondary sorting system is provided with two sets of parallel secondary classifiers, and the five-branch classifier and the six-branch classifier are respectively provided with two sets of parallel secondary classifiers;

a second distributor is arranged between the two five-branch machines and the second hoisting machine, the second distributor has a three-way structure, a mixing cavity is arranged at the intersection of the three-way structure, and the mixing cavity is used for uniformly mixing mortar entering the two five-branch machines from the second hoisting machine;

the discharge ports of the two six sub-machines share a third finished product pool, and the overflow ports share a fourth finished product pool.

[ III ] A

The bottom screen part of the primary classifier is a water filter screen with a circular hemispherical surface, and the water filter screen is provided with a plurality of water filter holes;

the sand supply pipe comprises a sand inlet pipe and a mixing cavity, the mixing cavity is cylindrical or spherical, and a pair of impellers is arranged in the mixing cavity; one side of the mixing cavity is opened and communicated with the side wall of the barrel body, and the other side of the mixing cavity is communicated with the sand inlet pipe;

the outlet is arranged at the center of the bottom of the barrel body, penetrates through the water filter screen and the water supply cavity and extends downwards.

Give the sand pipe and be equipped with 2~4, and all give the sand pipe and all install on the position of staving outer wall same height, respectively give the star type distribution that the sand pipe is central symmetry.

The sand feeding pipe is arranged at a half height position between the top end of the barrel body and the upper edge of the water filtering net.

The impeller is provided with an impeller shaft, an impeller body and a plurality of impeller blades, the impeller shaft is transversely arranged, two ends of the impeller shaft are fixedly assembled in the mixing cavity, the impeller body is sleeved outside the impeller shaft, and the impeller blades are all fixedly arranged on the impeller body.

The impeller shafts are horizontally arranged, the two impeller shafts are longitudinally arranged, and the impeller blades are mutually inserted.

The sand inlet pipe is obliquely arranged, and one end of the sand inlet pipe, which is far away from the barrel body, is upwards inclined.

[ IV ] A composition for treating diabetes

A separation process for wet separation of petroleum fracturing sand is characterized in that:

the sorting process comprises the following steps:

(1) the method comprises the following steps that mortar is pumped out by a mortar pump of a sand dredger and conveyed to a pretreatment system through a pipeline, desliming concentration is carried out through a first swirler, a first impurity screen is supplied for impurity removal after concentration, the material after impurity removal is supplied to a zero classifier for concentration and then supplied to a first scrubber for scrubbing, the scrubbed material is discharged to a desliming mortar pool for desliming lifting, the material is lifted to a second swirler for desliming concentration through a first lifter, and classification is waited;

(2) the mortar obtained in the last step enters a primary separation system, is supplied to a first-order separator with 40/70 meshes for primary separation, the ore discharged by the first-order separator enters a second-order separator with 40/70 meshes for secondary separation, the ore discharged by the second-order separator is a finished product with 40/70 meshes, and the overflow enters a finished product with 50/100 meshes;

the overflow of the separator enters a three-branch separator with 50/100 meshes for primary separation, the ore discharge of the three-branch separator enters a four-branch separator with 50/100 meshes for fine separation, the ore discharge of the four-branch separator is 50/100 meshes of finished products, and the overflow confluence of the three-branch separator and the four-branch separator enters a secondary separation system after being reprocessed by a secondary treatment system;

(3) conveying the mortar entering the secondary separation system from the primary separation system to a stabilized ore classifier of the secondary treatment system for concentration and dehydration, scrubbing, desliming and lifting by a second scrubbing machine, and then performing secondary separation;

(4) the mortar treated by the secondary treatment system enters a five-branch machine with 70/140 meshes, ore discharge of the five-branch machine enters a six-branch machine with 70/140 meshes for ore dressing, the ore discharge of the six-branch machine is a finished product with 70/140 meshes, and the overflow is a finished product with 100/200 meshes.

The beneficial effects are as follows:

(1) by adopting a sinking-floating separation technology with non-centrifugal force or without centrifugal force as a main factor, through a multi-stage hydraulic classification production line and a production process, silica sand with different specifications can be rapidly screened at one time through one set of production line, and the screening efficiency of hydraulic classification of the silica sand is greatly improved;

(2) two sets of parallel classifiers are adopted, which has the functions of improving the classification efficiency, balancing the mortar supply amount of the feeding system, the pretreatment system and the secondary treatment system, and enabling the supplied mortar to dispersedly enter the parallel separation system so as to control the flow, the flow velocity and relevant process parameters of each classifier, thereby achieving the purpose of adjusting the classification level;

(3) the bottom of the sorting equipment with the hemispherical barrel bottom is arc-shaped, and the entering water flow is uniform and stable, so that a mobile phase medium with stable ascending water flow is formed, the mortar at the bottom of the barrel body is fully dispersed, and is effectively separated in the ascending flow process. The circular arc-shaped water filtering net can also maximize the contact area, distribute more water filtering holes and construct a more stable mobile phase.

Drawings

The attached drawings are as follows:

FIG. 1 is a schematic diagram of the overall structure and layout of a sorting device according to an embodiment of the present invention, which is shown in a vertical view, and a part of the structure and the connection relationship are hidden by overlapping or not specifically shown;

FIG. 2 is a schematic flow chart of a sorting device and a sorting process according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a primary classifier according to a first embodiment of the present invention, in which:

a is the position of the sand supply pipe and the material flow direction,

b is the position of the water inlet pipe and the material flow direction,

c is the position of the overflow groove (and the matched pipeline) and the material flow direction,

d is the position of the discharge port and the material flow direction;

FIG. 4 is a schematic structural diagram of a primary classifier according to a third embodiment of the present invention;

FIG. 5 is a schematic top view of a primary classifier according to a third embodiment of the present invention, which mainly shows a star-shaped distribution structure of a plurality of sand feeding pipes;

FIG. 6 is a schematic structural view of a sand feed pipe in the third embodiment of the present invention;

fig. 7 is a schematic structural view of the sand feeding pipe in the third embodiment of the present invention, which is obliquely arranged.

As can be seen from the figure:

1 barrel 10 bottom sieve part 11 water filter screen 12 water filter hole

2 sand feeding pipe 21, sand feeding pipe 22, mixing cavity 23, impeller 24, impeller shaft 25, impeller shaft 26 and impeller blades

3 water inlet pipe 4 overflow trough 5 outlet.

Detailed Description

The invention relates to a wet-type separation device and a method, which are used for separating silica sand by using a fluid material, namely water, and adopts the principle that a sinking-floating separation technology without centrifugal force or the main factor of which is not the centrifugal force is adopted, and silica sand with different specifications can be rapidly screened at one time through a set of production line through a multi-stage hydraulic classification production line and a production process, so that the screening efficiency of hydraulic classification of the silica sand is greatly improved. The one-time operation in the primary rapid screening means a production line type production mode through the production line, that is, the mortar raw material is continuously supplied by the feeding system, and various processing devices and devices in the pretreatment system also perform operations such as filtering, concentrating, dehydrating, scrubbing, lifting and the like on the mortar in a flowing manner, so that the mortar mainly composed of water sand is continuously supplied to the primary sorting system and the secondary sorting system. The primary and secondary sorting system includes several classifiers, such as one, two and five classifiers, which are arranged from top to bottom and communicated via pipelines with different functions, and the mortar may flow via gravity to form one linkage system. The following mainly takes four specifications of silica sand with 40/70, 50/100, 70/140 and 100/200 meshes produced by the applicant as an example to illustrate the specific structure, connection relationship, use method, process conditions and the like of the sorting device.

The application the working principle of the technical scheme of the sorting device and the sorting process is as follows:

as shown in fig. 1 and 2, raw sand (mortar) is pumped out by a mortar pump of a sand dredger, is conveyed to a swirler (a first swirler) of a washing workshop (a pretreatment system) through a pipeline for desliming and concentration, is supplied to an impurity screen (the first impurity screen) for impurity removal after concentration, is supplied to a raw ore classifier (namely a zero classifier) for concentration after impurity removal, is then supplied to a scrubber (the first scrubber) for scrubbing, is discharged to a desliming mortar pool for desliming and lifting, and is lifted to the swirler (a second swirler) by a lifter (the first lifter) for desliming and concentration to wait for classifying the mortar.

The mortar to be classified enters a primary sorting system and is supplied to a primary sorting classifier (a primary classifier) of 40/70 meshes for primary sorting. The ore discharged by the primary sorting grader of 40/70 meshes enters a fine sorting grader (secondary sorting machine) of 40/70 meshes for secondary ore dressing, the ore discharged by the fine sorting grader of 40/70 meshes is a finished product of 40/70 meshes, and the finished product overflows into a finished product pulp pool of 50/100 meshes.

The overflow of the 40/70-mesh primary separation classifier enters a 50/100-mesh primary separation classifier (a three-branch machine) for primary separation, the ore discharge of the 50/100-mesh primary separation classifier enters a 50/100-mesh fine separation classifier (a four-branch machine) for fine separation, the ore discharge of the 50/100-mesh fine separation classifier is 50/100-mesh finished products, and the overflow combined flow of the 50/100-mesh primary separation classifier and the fine separation classifier enters a secondary separation system after being reprocessed.

The mortar entering the secondary sorting system from the primary sorting system is obtained by overflowing the primary sorting system, the secondary sorting system and the quartering machine, so that the proportion of silica sand in water in the mortar is small, the secondary sorting system is not beneficial to screening, the mortar contains more fine sand of 70-200 meshes, the sand grains are fine, and the secondary sorting is beneficial to the secondary sorting after the secondary sorting is needed to be processed again.

Therefore, the mortar sand entering the secondary separation system is fine, and needs to be conveyed to a fine ore classifier for concentration and dehydration, and then scrubbed, deslimed and lifted to perform secondary separation. The retreated mortar enters an 70/140-mesh primary classifier (five-stage classifier), ore discharge of the 70/140-mesh primary classifier enters a 70/140-mesh fine selection classifier (six-stage classifier) for mineral separation, the ore discharge of the 70/140-mesh fine selection classifier is 70/140-mesh finished products, and overflow of the 70/140-mesh fine selection classifier is 100/200-mesh finished products. And the ore discharge of all the classifiers is controlled by automatic discharging. And lifting the finished product to a finished product swirler through a pipeline for concentration and stacking.

[ EXAMPLES one ]

As shown in fig. 1, 2 and 3, the sorting device for wet sorting the oil fracturing sand is characterized in that:

the sorting device comprises a feeding system, a pretreatment system, a primary sorting system and a secondary sorting system, wherein the feeding system is used for continuously supplying mortar raw materials to the sorting device from a mortar source place, the pretreatment system is used for carrying out operations including but not limited to dehydration, concentration, impurity removal, wiping and lifting on the mortar raw materials supplied by the feeding system, the primary sorting system is used for carrying out coarse product sorting on the mortar processed by the pretreatment system, and the secondary sorting system is used for carrying out fine product sorting on the mortar sorted by the primary sorting system; the coarse product is a silica sand product with the mesh number within the range of 40-100, and the fine product is a silica sand product with the mesh number within the range of 70-200. The mortar is a mixture which takes water and sand as main components and possibly contains a small amount of impurities such as mud, dirt, garbage and the like, and the types and the contents of the impurities in the mortar are different according to different operation positions of sand extraction ships and different sand sources.

the first cyclone is used for dehydrating and concentrating the mortar;

the first scrubbing machine is used for scrubbing mortar, namely mud on the surface of sand grains is removed through friction, impact, collision and blocking among the sand grains and between the sand grains and the scrubbing machine; the scouring machine can adopt any prior known technology, such as Chinese patent CN209287846U silica sand scouring machine;

the first lifting machine is used for lifting the mortar to a high place; the elevator can adopt any existing known technology, such as Chinese patent CN104454621B differential pressure type evacuation-proof mortar pump, and commercially available pumping devices with various specifications and materials can be used, and are described again and again;

the second cyclone is used for dehydrating and concentrating the mortar;

the second impurity sieve is used for removing impurities except water and sand in the mortar.

The first cyclone and the second cyclone have the same function, are dehydrated and concentrated, but the processed materials are different, the first cyclone is mortar with cement sand impurities, and the second cyclone is a water-sand-mud mixture filtered by the first impurity screen; the cyclone can adopt any prior known technology, such as a hydraulic cyclone for preparing kaolin in Chinese patent CN210207250U, a mining cyclone in CN210207254U and the like.

The concentration is to control the water content of the mortar, so that the water content in the mortar is relatively low, and the production efficiency of the subsequent treatment steps is improved.

The first impurity sieve and the second impurity sieve have the same function and are both filtering functions, but the processed materials are different; the first impurity is a coarse sieve and is mainly used for filtering impurities except water, sand and mud, such as large impurities of branches, leaves, aquatic plants, garbage and the like, and the filtering passing property is high; the materials treated by the second impurity are the mortar after being filtered, scrubbed by a scrubbing machine, dehydrated, concentrated and deslimed, the main components of the mortar are water and sand, the sand material can also play a certain crushing role when being scrubbed by the scrubbing machine, and the large sand grains in the mortar are relatively less, so the second impurity is preferably screened by a fine screen, and the sand grains with larger grain sizes are mainly screened, namely the maximum grain size of the mortar passing through the second impurity basically meets the requirements of maximum specification products (the mesh number is minimum and the grain size is maximum). The impurity sieve can adopt any prior known technology, such as a Chinese patent CN208743002U rolling sieve machine, a CN201524655U rolling sieve and the like.

as shown in fig. 3, the primary classifier is in a cylindrical shape and is provided with a sand supply pipe (a position and material flow direction), a water inlet pipe (B position and material flow direction), an overflow groove (C position and material flow direction), and a discharge port (D position and material flow direction); the water inlet pipe is arranged at the bottom of the primary classifier and is used for supplying water to the primary classifier; the sand supply pipe is arranged above the primary classifier and extends into the primary classifier to supply mortar to the primary classifier; the overflow groove is arranged on the outer side of the upper edge of the barrel wall of the primary classifier and is used for receiving the materials overflowed from the upper edge of the primary classifier; the discharge port is arranged at the bottom of the primary classifier;

and the discharge ports of the four sub-machines are connected with the second finished product pool, and overflow chutes of the four sub-machines are connected into a secondary sorting system through pipelines.

the secondary classifier adopts the same structure as the primary classifier;

The sand extraction ship, the first cyclone, the first impurity sieve, the zero classifier, the first scrubbing machine, the first hoister, the second cyclone, the second impurity sieve and the sorter are sequentially connected; the devices are connected in sequence, namely the devices are connected end to end and connected in series according to the sequence, and materials (namely mortar) flow through the devices in sequence and are conveyed and processed;

the second scrubbing machine has the same structure as the first scrubbing machine, the size specification of the second scrubbing machine is smaller than that of the first scrubbing machine, and the outlet of the second scrubbing machine is connected with a second hoisting machine; the scouring machine can adopt any prior known technology, such as Chinese patent CN209287846U silica sand scouring machine;

The primary classifier comprises a barrel body, a bottom sieve part is arranged in the barrel body, the bottom sieve part is inverted at the bottom of the barrel, the upper edge of the bottom sieve part is connected with the side wall of the primary classifier barrel, the tip of the lower part of the bottom sieve part abuts against the middle position of the bottom surface of the primary classifier barrel, and a discharge port of the bottom surface of the primary classifier barrel is communicated with the bottom of the bottom sieve part.

The zero classifier adopts the same structure as the primary classifier;

[ example two ]

As shown in fig. 2, on the basis of the above embodiment, the primary sorting system of the present embodiment is provided with two sets of parallel primary classifiers, each of the primary classifier, the secondary classifier, the tertiary classifier and the quartering classifier is provided with two sets;

The first distributor and the second distributor (hereinafter collectively referred to as distributors) have the same structure; the distributor is provided with a tee joint structure, the inlet end of the tee joint is connected with an upstream sand inlet pipeline, the mortar conveyed in the sand inlet pipeline is usually unevenly dispersed, namely, sand is mostly concentrated on the pipe wall, and if the mortar is directly fed into a classifier (such as a classifier and a classifier with five classifiers) of a sorting system, excessive heterogeneity of a water-sand dispersion system in the classifier is easily caused, so that the classification effect is influenced. On the basis, a mixing cavity is arranged at the intersection of the three ways of the distributor, the mixing cavity is a large-space cavity body in the shape of a box or a sphere and the like, mortar conveyed from the inlet end of the distributor reaches the mixing cavity, the mortar is rolled and stirred in the mixing cavity to be uniformly mixed, and the mortar entering the classifier from the outlet end of the mixing cavity is beneficial to being quickly dispersed into the classifier.

In addition, the primary sorting system and/or the secondary sorting system adopts two sets of parallel classifiers, and the functions of the primary sorting system and/or the secondary sorting system are to improve the classification efficiency, balance the mortar supply amount of the feeding system, the pretreatment system and the secondary treatment system, and enable the supplied mortar to dispersedly enter the parallel sorting system so as to control the flow, the flow velocity and relevant process parameters of each classifier, thereby achieving the purpose of adjusting the classification level.

[ EXAMPLE III ]

As shown in fig. 4 to 7, on the basis of the above embodiments, the bottom screen portion of the primary classifier of the present embodiment is a water filtering net with a circular hemispherical surface, and the water filtering net is provided with a plurality of water filtering holes;

The primary classifier comprises a barrel body, a sand supply pipe, a water inlet pipe, an overflow trough and a discharge port;

the barrel body is in a cylindrical shape, the upper end of the barrel body is opened, the bottom of the barrel body is provided with a water filtering net, the water filtering net is in a circular hemispherical surface, and the water filtering net is provided with a plurality of water filtering holes; the water filter screen is a plate-shaped component with a plurality of through holes, and is arranged at the bottom of the barrel body and seals the bottom of the barrel body, so that the barrel body is in a structure of an upper barrel and a bottom semi-spherical surface; the upper edge of the semispherical water filtering net is fixedly connected with the side wall of the bottom of the barrel body or is connected into a whole.

The general silica sand hydraulic separation equipment generally adopts a conical bottom, the outline of the conical bottom is linear, the sand with large particle size at the bottom of a barrel body can be conveniently collected to the conical top end (the conical top end is inverted and downwards), and the sand with large particle size can be quickly discharged; however, the conventional conical bottom sorting equipment is not beneficial to fully separating mortar at the bottom of the barrel body, the interference is serious in the screening process, and the separation precision is not good. The bottom of the sorting equipment with the hemispherical barrel bottom is arc-shaped, and the entering water flow is uniform and stable, so that a mobile phase medium with stable ascending water flow is formed, the mortar at the bottom of the barrel body is fully dispersed, and is effectively separated in the ascending flow process. The circular arc-shaped water filtering net can also maximize the contact area, distribute more water filtering holes and construct a more stable mobile phase.

The sand supply pipe comprises a sand inlet pipe and a mixing cavity, the mixing cavity is cylindrical or spherical, and a pair of impellers is arranged in the mixing cavity; one side of the mixing cavity is opened and communicated with the side wall of the barrel body, and the other side of the mixing cavity is communicated with the sand inlet pipe; the mixing cavity is a cavity structure with a cavity, one side of the cavity (cavity wall) close to the barrel body is fixedly connected or connected with the side wall of the barrel body into a whole, and an opening on the side of the mixing cavity is communicated with the barrel body, so that mortar conveyed by the sand inlet pipe enters the barrel body. The pair of impellers in the mixing cavity is used for mixing the mortar from the sand inlet pipe again to ensure that the sand and the water are fully and uniformly mixed and enter the barrel body at a constant flow rate with a certain threshold value, so that the mortar entering the barrel body is uniformly and quickly dispersed into a flowing phase of the barrel body on the one hand, and on the other hand, the pipeline pressure in the sand inlet pipe can be fully offset through the action of the impellers, and the damage of the mortar in the sand inlet pipe to the well-balanced flowing phase state established by the barrel body is reduced.

The water inlet pipe supplies continuous clear water to the barrel body, and the water enters the barrel body from the water filtering holes on the water filtering net, so that upward water flow is formed; due to the driving of water flow, mortar at the bottom of the barrel body can be separated through hydraulic sinking and floating, the light sand is on the upper part and the heavy sand is on the lower part, the arc-shaped water filtering net is in gentle transition, sand is not gathered to the bottom rapidly in a large amount, but is gathered to the upper edge of the discharge port slowly along the edge of the water filtering net during scouring, and the separation effect is good.

Furthermore, give the sand pipe and be equipped with 2~4, and all give the sand pipe and all install on the position of staving outer wall same height, each is the star type distribution of central symmetry for the sand pipe. The conventional silica sand separation equipment mostly adopts a middle sand inlet pipe, namely, one pipe extends into the middle of the barrel body, mortar is directly discharged into the barrel body, the sand inlet mode seriously damages an established balanced (dynamic balance) mobile phase dispersion system in the barrel body, sand and water and sand with different particle sizes are always in a diffusion process (continuously fed due to the sand inlet pipe), namely, the process of density uniformity is realized, or the separation is carried out while dispersion is carried out in the diffusion process, the interference among sand grains in the separation process is serious, and the separation precision is not high. The embodiment will advance the sand pipe branch and be a plurality ofly to carry the mortar from staving lateral wall middle part, the speed that the mortar got into the staving reduces, the dispersion is even, reduces to interfere, does benefit to the separation.

The sand feeding pipe is arranged at a half height position between the top end of the barrel body and the upper edge of the water filtering net. The water filter screen is arc-shaped, the upper edge of the water filter screen extends upwards further, so that water flow at the edge position of the barrel body can flow, and the mortar entering from the sand supply pipe is promoted to diffuse quickly.

The impeller is provided with an impeller shaft, an impeller body and a plurality of impeller blades, the impeller shaft is transversely arranged, two ends of the impeller shaft are fixedly assembled in the mixing cavity, the impeller body is sleeved outside the impeller shaft, and the impeller blades are all fixedly arranged on the impeller body. The impeller shafts are horizontally arranged, the two impeller shafts are longitudinally arranged, and the impeller blades are mutually inserted. The sand inlet pipe is vertical to the plane of the two impeller shafts of the impeller. From the design and manufacture point of view, the sand inlet pipe is vertically arranged with the plane where the two impeller shafts are located, which is beneficial to saving the cost, but from the practical efficacy point of view of the sorting equipment, a certain angle is preferably formed between the sand inlet pipe and the plane where the two impeller shafts are located, so that the mortar in the sand inlet pipe is prevented from directly rushing into the barrel body. In addition, a pair of impellers rotate in a power mode, namely the impellers rotate only by the impact of mortar, and the two impellers are close to each other, so that impeller blades are mutually overlapped in a staggered mode and mutually restricted, and unilateral rotation and over-high flow speed are avoided.

Further, as shown in fig. 7, the sand inlet pipe is obliquely arranged, and one end of the sand inlet pipe, which is far away from the barrel body, is inclined upwards, so that impact of mortar in the sand inlet pipe on a dispersion system (water-sand mixture) in the barrel body is avoided, and the hydraulic classification effect is not affected.

Claims

1. The utility model provides a sorting unit for wet process is selected separately oil fracturing sand which characterized in that:

the first cyclone is used for dehydrating and concentrating the mortar;

the first scrubbing machine is used for scrubbing mortar;

the first lifting machine is used for lifting the mortar to a high place;

the second cyclone is used for dehydrating and concentrating the mortar;

the secondary classifier adopts the same structure as the primary classifier;

2. The sorting device for wet sorting petroleum frac sand according to claim 1, wherein:

3. The sorting device for wet sorting petroleum frac sand according to claim 2, wherein:

4. A sorting apparatus for wet sorting petroleum frac sand according to claim 1, 2 or 3, wherein:

5. The sorting device for wet sorting petroleum frac sand according to claim 4, wherein:

6. The sorting device for wet sorting petroleum frac sand according to claim 5, wherein:

the zero classifier adopts the same structure as the primary classifier;

7. The sorting device for wet sorting oil frac sand according to claim 1, 2, 3, 5 or 6, wherein:

8. The sorting device for wet sorting oil frac sand according to claim 1, 2, 3, 5 or 6, wherein:

9. The sorting device for wet sorting oil frac sand according to claim 1, 2, 3, 5 or 6, wherein:

the discharge port is arranged in the center of the bottom of the barrel body, penetrates through the water filter screen and the water supply cavity and extends downwards;

2-4 sand supply pipes are arranged, all the sand supply pipes are arranged at the same height on the outer wall of the barrel body, and the sand supply pipes are distributed in a centrosymmetric star shape;

the sand supply pipe is arranged at a half height position between the top end of the barrel body and the upper edge of the water filtering net;

the impeller is provided with an impeller shaft, an impeller body and a plurality of impeller blades, the impeller shaft is transversely arranged, two ends of the impeller shaft are fixedly assembled in the mixing cavity, the impeller body is sleeved outside the impeller shaft, and the impeller blades are all fixedly arranged on the impeller body;

the impeller shafts are horizontally arranged, the two impeller shafts are longitudinally arranged, and the impeller blades are mutually inserted;

10. A sorting process for wet sorting petroleum frac sand using the sorting device of claim 1 or 2 or 3 or 5 or 6 for silica sand classification, wherein:

the sorting process comprises the following steps: