CN112090168A

CN112090168A - Long-period continuous operation precoating filtering system

Info

Publication number: CN112090168A
Application number: CN202010973386.XA
Authority: CN
Inventors: 宋永飞; 张建龙; 陈涛
Original assignee: Beijing Zhongke Yongyi Technology Co ltd
Current assignee: Beijing Zhongke Yongyi Technology Co ltd
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2020-12-18

Abstract

The invention discloses a precoating filtering system capable of continuously operating for a long period, and relates to the technical field of filtering devices. The device comprises a pre-coating unit, an auxiliary agent unit and a filtering unit, wherein the pre-coating unit comprises a pre-coating feeding device, a pre-coating tank and a pre-coating circulating pump, the auxiliary agent unit comprises an auxiliary agent feeding device, an auxiliary agent tank and an auxiliary agent pump, and the filtering unit comprises a blade type filter, a slag discharging trolley and a filtrate tank; the precoating filtering system is also provided with an oil slurry raw material valve, the blade type filter is provided with a filter shell and filter blades, and the filter blades are provided with a plurality of groups and are arranged in the filter shell. The invention has good filtering effect on catalytic cracking slurry oil, can realize full automation, automatically switches the filter, avoids solid impurities from blocking the filter medium in a pre-coating mode before filtering, greatly prolongs the service life of the filter medium, and can realize long-period continuous operation.

Description

Long-period continuous operation precoating filtering system

Technical Field

The invention relates to the technical field of filtering devices, in particular to a precoating filtering system capable of continuously operating for a long period.

Background

The solid catalyst powder in the slurry oil is mainly fine crystal particles formed by abrasion or thermal stress cracking of the catalyst under the high temperature and fluidization conditions of the catalytic cracking unit. The solid powder is highly dispersed in the oil slurry, and the solid content is about 3000-20000 ppm. The separation of the catalyst fines from the slurry is difficult because of the promotion and stabilization of the dispersion of suspended particles by the presence of colloids, asphaltenes, and impurities such as sulfur, nitrogen, and metal compounds in the slurry. As solid impurities exist in the slurry oil, more solid matters not only aggravate the erosion of pipelines and equipment, but also have the danger of blocking a furnace nozzle, and seriously affect the quality of fuel oil. Therefore, if the solid in the slurry oil can be filtered out, the quality of the slurry oil can be improved, and the slurry oil which can only be used as fuel oil or delayed coking raw material can be used for producing carbon black, needle coke, even carbon fiber and the like, thereby increasing the added value of the slurry oil product.

The slurry filter is a continuously operated solid-liquid separation apparatus capable of filtering solids of 5 μ or more in slurry. At present, the catalytic cracking slurry oil is mainly separated from the catalyst powder by adopting a metal powder sintered filter element filter and a metal wire mesh sintered filter element filter worldwide, and industrialized devices with different scales are operated worldwide. However, the devices and techniques introduced abroad or existing domestically have a short industrial operating time, the maximum continuous operating period is only about 1 year, and most devices are abandoned. These filters have the problem that solid particles can easily enter the filter element, so that the blockage is difficult to clean and regenerate and even is permanently blocked. And this type filter core is not stand wear and tear, blocks up the damage easily, needs frequent change, greatly increased later maintenance cost and operating cost. In the process, the filter needs to be frequently switched to be cleaned and regenerated, and the regeneration time is long. Frequent switching operation is required between the filters, and the quality requirement of a switching valve is high under the conditions of high temperature and solid particle content. Moreover, because the particles in the oil slurry are fine and the particles below 1 micron account for 0.5-5%, the existing filtering technology is difficult to realize higher filtering precision requirement.

Disclosure of Invention

The invention aims at the technical problems in the prior art and provides a precoating filtering system which can continuously run for a long period.

In order to solve the technical problem, the invention comprises a pre-coating unit, an auxiliary agent unit and a filtering unit, wherein the pre-coating unit comprises a pre-coating feeding device, a pre-coating tank and a pre-coating circulating pump, the auxiliary agent unit comprises an auxiliary agent feeding device, an auxiliary agent tank and an auxiliary agent pump, and the filtering unit comprises a blade type filter, a slag discharging trolley and a filtrate tank; the precoating filtering system is also provided with an oil slurry raw material valve, the blade type filter is provided with a filter shell and filter blades, and the filter blades are provided with a plurality of groups and are arranged in the filter shell.

Preferably, the lower part of the blade type filter is connected with a filter feed valve and a filter outlet valve, the precoating feeding device is connected with the upper end of the precoating tank, the lower part of the precoating tank is connected with the filter feed valve through a precoating circulating pump and a precoating pipeline, the precoating pipeline is connected with a precoating valve, and the filter outlet valve is connected with the precoating tank through a connecting pipeline and a precoating circulating valve; the auxiliary agent feeding device is connected with the upper end of the auxiliary agent tank, the lower part of the auxiliary agent tank is connected with the auxiliary agent pump, the auxiliary agent pump is connected with the oil slurry raw material valve through an auxiliary agent valve and a connecting pipeline, the oil slurry raw material valve is connected with the filter feeding valve through a connecting pipeline, the filter outlet valve is connected with the filtrate tank through a connecting pipeline and a filtrate valve, and the residue discharge trolley is arranged at the bottom of the blade type filter.

Preferably, the precoating filtering system is further provided with a nitrogen valve and a gas vent valve, the upper part of the blade type filter is connected with a filter air inlet valve, the nitrogen valve is connected with the filter air inlet valve through a connecting pipeline, and the filter outlet valve is connected with the gas vent valve through a connecting pipeline.

Preferably, a plurality of groups of filter blades are vertically arranged in the filter shell, spaces are formed between the adjacent filter blades, filter screens cover the filtering surfaces of the filter blades, each filter screen is composed of a plurality of layers of stainless steel wire meshes, and pre-coating layers are connected to the filter screens in a supporting manner; the bottom of the filter blade is connected with a liquid collecting pipe, the center of the bottom of the filter blade is provided with a nozzle, and the nozzle is inserted into the liquid collecting pipe arranged below the nozzle.

Preferably, the distance between adjacent filter blades is 30-100mm, the blade type filter is also connected with a spraying device, the spraying device is provided with a spraying valve, a filter spraying inlet valve and a spraying head, the spraying valve is connected with the filter spraying inlet valve through a spraying pipeline, the spraying head is arranged in the filter shell and arranged at the upper end of the filter blades, and the spraying heads are arranged in parallel.

Preferably, the filter feeding valve is connected with a filter feeding hole arranged at the bottom of the blade type filter, and a feeding baffle is arranged at the filter feeding hole; the upper end of the blade type filter is connected with an oscillator assembly, the oscillator assembly is provided with an oscillator and an oscillator transmission shaft, the oscillator is arranged on the outer side of the filter shell, and the oscillator is connected with the upper end of the filter blade through the oscillator transmission shaft.

Preferably, the bottom of the blade filter is of an inverted frustum structure, and the intersection angle of the oblique edge of the bottom of the blade filter and the horizontal plane is 60 degrees.

Preferably, a bag filter is connected to the leaf filter, and two leaf filters are arranged in the filter unit, namely a first leaf filter and a second leaf filter.

Preferably, the precoating powder used in the precoating unit is diatomite, cellulose powder or bleaching earth, and the auxiliary agent powder used in the auxiliary agent unit is the same material and grade as the precoating powder.

Preferably, the precoating feeding device and the auxiliary agent feeding device are both provided with a dust removal device, the inside of the precoating tank and the inside of the auxiliary agent tank are both provided with a stirring device, the tops of the precoating tank and the auxiliary agent tank are both provided with a feeding orifice, and the precoating circulating pump and the auxiliary agent pump are both provided with at least one.

Compared with the prior art, the invention has the following beneficial effects:

1) the invention has compact structure, small floor area, large filtering area and less investment for users in earlier stage; the blade type filter can realize full-automatic operation, all the processes can be automatically completed in a linkage manner, the operation is simple, the performance is safe and reliable, and the later maintenance cost is low.

2) The invention sets two blade type filters, one is opened and the other is prepared, and the filters are automatically switched; when one filter is precoated or subjected to other non-filtration processes, the other filter is put into use, so that continuous filtration of the oil slurry can be ensured.

3) According to the invention, the filter medium is precoated, so that solid impurities can be effectively prevented from directly contacting with the filter medium and being not blocked; the liquid to be filtered can obtain satisfactory clarity from the beginning; the filter medium is beneficial to cleaning after the filtering period is finished, the long-period operation of the oil slurry filtering device can be ensured, and the service life of the filter medium is greatly prolonged.

4) According to the invention, each filter blade is provided with the nozzle, and the nozzle structure can improve the flow of the drying air flow and ensure that the filter cake of the filter is dry and has the minimum liquid loss. Through laboratory test and experience of industrial operation devices, the oil slurry filtering device has excellent filtering effect on oil slurry, the solid content in the filtered oil slurry is low, and the oil slurry can continuously run for a long period.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a leaf filter according to the present invention;

FIG. 3 is a schematic view of the construction of a filter blade according to the present invention.

The symbols in the figures indicate:

1. a leaf filter; a first leaf filter; a second leaf filter; 101. a filter housing; 102. a filter blade; 103. filtering with a screen; 104. a liquid collecting pipe; 105. a nozzle; 106. a spraying device; 107. a shower pipe; 108. a shower head; 109. an oscillator assembly; 110. an oscillator; 111. an oscillator drive shaft; 112. a feed baffle; 2. a slag discharge trolley; 3. an auxiliary agent tank; 4. a precoating tank; 5. a filtrate tank; 6. an auxiliary agent pump; 7. a pre-coating circulating pump; 8. an auxiliary agent feeding device; 9. a precoating feeding device; 10. a precoating valve; a first filter feed valve; a second filter feed valve; 12a. a first filter outlet valve; a second filter outlet valve; 13. a pre-coating circulating valve; 20. an oil slurry stock valve; 21. an auxiliary valve; 22. a filtrate valve; 23. an additive circulating valve; 30. a nitrogen gas valve; 31a first filter inlet valve; 31b. a second filter inlet valve; 32. a raffinate discharge valve; 40. a gas release valve; 50. a spray valve; 51a first filter spray inlet valve; 51b. second filter spray inlet valve.

Detailed Description

The invention is further described below in conjunction with the drawings and the specific embodiments to assist in understanding the contents of the invention. Terms used in the present invention are all terms that are conventional in the industry, unless otherwise specified.

The precoating filtering system not only can be applied to oil slurry filtration, but also can be applied to other raw materials to be filtered, such as paraffin filtration, coal tar filtration, dilute ammonium sulfate liquid filtration and the like.

Referring to fig. 1 to 3, the present invention provides a long-period continuous operation precoating filtration system comprising a precoating unit including a precoating feeding device 9, a precoating tank 4 and a precoating circulating pump 7, an auxiliary unit including an auxiliary feeding device 8, an auxiliary tank 3 and an auxiliary pump 6, and a filtration unit including a first vane filter 1a, a second vane filter 1b, a slag discharge cart 2 and a filtrate tank 5.

In this embodiment, two leaf filters 1 are provided, one is provided, and when one of the leaf filters is precoated or otherwise non-filtering, the other is used to perform the filtering process, the first leaf filter 1a and the second leaf filter 1b have the same structure, and the complete process is described only with the second leaf filter 1b.

As shown in fig. 1, a first filter inlet valve 11a and a first filter outlet valve 12a are connected to a lower portion of the first leaf filter 1a, and a second filter inlet valve 11b and a second filter outlet valve 12b are connected to a lower portion of the second leaf filter 1 b; the precoating feeding device 9 is connected with the upper end of the precoating tank 4, the lower part of the precoating tank 4 is connected with a precoating circulating pump 7, the precoating circulating pump 7 is connected with a first filter feed valve 11a and a second filter feed valve 11b through a precoating pipeline, the precoating pipeline is connected with a precoating valve 10, and a first filter outlet valve 12a and a second filter outlet valve 12b are respectively connected with the precoating tank 4 through connecting pipelines and a precoating circulating valve 13. The auxiliary agent feeding device 8 is connected with the upper end of the auxiliary agent tank 4, the lower part of the auxiliary agent tank 4 is connected with the auxiliary agent pump 6, and the outside of the auxiliary agent pump 6 is connected with an auxiliary agent valve 21; the auxiliary agent valve 21 is connected with the oil slurry raw material valve 20 through a connecting pipeline, the oil slurry raw material valve 20 is connected with the first filter feeding valve 11a and the second filter feeding valve 11b through connecting pipelines, and oil slurry enters the vane type filter through the oil slurry raw material valve 20. The second leaf filter 1b is provided with a filter housing 101 and a filter vane 102, and the filter vane 102 is provided in the filter housing 101.

Furthermore, in this embodiment, the precoating feeding device 9 and the auxiliary agent feeding device 8 are both provided with dust removing devices for absorbing dust generated during feeding; the top of the precoating tank 4 and the top of the auxiliary agent tank 3 are both provided with feeding orifices for adding precoating powder and auxiliary agent respectively, and the auxiliary agent tank 3 and the precoating tank 4 are both internally provided with stirring devices, so that the auxiliary agent in the auxiliary agent tank 3 and the precoating liquid in the precoating tank 4 are uniformly stirred by the stirring devices respectively.

In this embodiment, at least one precoating circulating pump 7 and at least one auxiliary pump 6 should be provided.

In this embodiment, the precoating unit mainly performs preparation of the precoating liquid and precoating of the filter blade 102, and first, precoating powder enters the precoating tank 4 filled with clear liquid through the precoating feeding device 9 and the feeding orifice at the top of the precoating tank 4, and the stirring device is started to stir the precoating liquid uniformly until the precoating liquid is fully mixed. While stirring and mixing, the volume and concentration of the precoating liquid are determined according to the total volume of the pipe connected with the filter and the precoating tank 4. The clear liquid in the precoat tank 4 may be the filtrate from the filter, and any permissible light oil or the like may be used.

After being prepared as required, the precoating liquid is subjected to a precoating filter blade 102, and after coming out of the precoating tank 4, the precoating liquid sequentially passes through a precoating circulating pump 7, a precoating pipeline, a precoating valve 10, a second filter feed valve 11b, a second filter outlet valve 12b and a precoating circulating valve 13; the precoat liquid enters the second leaf filter 1b through the second filter feed valve 11b, passes through the filter vanes 102, and then returns to the precoat tank 4 through the filter discharge port via the precoat circulation valve 13. Thereby cyclically driving the precoat liquid into the second leaf filter 1b to cyclically coat the filter leaf 102 with a precoat layer. During precoating, when the liquid in the filter becomes relatively clear, indicating that the precoating layer is precoated in place, the precoating process is complete.

Furthermore, during the precoating process, the precoating rate is maintained at a relatively stable level to prevent the precoating layer from being uneven or falling off. The precoating rate is primarily dependent on the viscosity of the liquid, and should be sufficient to keep all of the precoating powder in suspension, but not so fast as to cause erosion of the precoating layer within the filter. For oil slurry, the precoating rate is 1.5-2 times of the filtration rate, and the precoating liquid is circulated from the filter filtrate outlet to the precoating tank 4 by feeding to improve the suspension state. The precoating aims to uniformly mix precoating powder with clean filtrate or other clear liquid, and then the precoating powder forms a porous and loose filter cake on the filter medium through circulating filtration, so that the blockage of impurities on the pores of the filter medium can be effectively prevented, the blockage of the filter medium is avoided, the filtration period is prolonged, the service life is prolonged, and the filtration precision is improved. The most important characteristic is that the solid catalyst is prevented from polluting the filter medium, and filter cake removal and filter medium cleaning are facilitated.

Furthermore, in this embodiment, the material of the precoating unit may be diatomaceous earth, cellulose powder, fuller's earth, etc. of high porosity, and a diatomaceous earth filter aid may be selected in order to obtain a clarified slurry product and require a high filtration rate.

Further, in this embodiment, the volume of the precoat liquid should be 1.25 times the sum of the filter cavity and the corresponding line volume.

In this embodiment, the auxiliary agent unit is mainly used to add the auxiliary agent powder to the vane filter 1, the solid particles in the slurry do not penetrate through the precoat layer and remain on the precoat layer, and the solid particles form a cake layer on the precoat layer, which will cause the filtration flow to decrease at a later stage if not treated, so that the filtration flow can be increased and the filtration cycle can be prolonged by adding the auxiliary agent system on the precoat layer, and the use amount of precoat material can be reduced and the cost can be saved. The auxiliary agent powder enters the auxiliary agent tank 3 through the auxiliary agent feeding device 8 and a feeding hole at the top of the auxiliary agent tank 3, and the auxiliary agent liquid is uniformly stirred through a stirring device arranged in the auxiliary agent tank 3. When the precoating operation is finished, the filter unit starts to work, the auxiliary agent pump 6 and the filter feeding pipeline are opened, and the precoating circulating pump 7 and the related pipelines are closed, so that the materials entering the filter are continuous, and sudden fluctuation of pressure cannot exist. As the filtration is carried out, the auxiliary agent powder is mixed with suspended solid impurities in the oil slurry and is deposited on the precoating layer, so that a new filter cake layer is continuously formed, fine filter aid particles have countless micro-channels and can block the suspended impurities but can not prevent clean liquid from passing through, and the addition of the auxiliary agent can improve the permeability of a filter cake and greatly prolong the filtration time of a single filter.

Furthermore, the selection of the auxiliary agent is mainly determined by the filtration purpose, the characteristics of the material to be filtered, the used filter medium and the like, the type, the particle size and the addition amount of the filter aid are determined so as to achieve the ideal filter aid effect, and the auxiliary agent powder is usually the same material and the same grade as the precoating powder.

Furthermore, the addition amount of the auxiliary agent is in direct proportion to the solid content in the oil slurry, the ratio of the addition amount of the auxiliary agent to the solid content in the oil slurry is 1: 2-1: 1, and the mass concentration of the auxiliary agent liquid is 3% -4%.

In the embodiment, the filtering unit filters the oil slurry to filter out solid particle impurities in the oil slurry; the filter unit is first precoated and formed into a precoat layer on the filter vanes 102 by the precoating unit, and then the passage of the liquid product through the filter media is achieved by applying a pressure differential across the filter media and the precoat layer. The filter is precoated prior to filtration and a suspension containing fine particulate material susceptible to clogging of the filter media pores can be filtered to a lower level by using an inert or porous filter aid material. As the material to be filtered passes through the precoat and filter vanes 102, the solid particles in the slurry are trapped, and a layer of solid particles deposits on and covers the precoat. The precoat layer thickens to become a "filter cake" with intricate channels, which allows for the filtration of finer particles.

Furthermore, a plurality of groups of filter blades 102 are arranged inside the second vane filter 1b, and are vertically arranged in the filter housing 101, and the filter blades 102 are used as a filter medium; the adjacent filter blades 102 are spaced apart from each other, and the distance between the adjacent filter blades 102 is 30-100mm according to the field requirement. The filtering surface of the filter blade 102 is covered with a filter screen 103, the filter screen 103 is composed of a plurality of layers of stainless steel wire meshes, and the filter screen 103 is used for supporting and keeping a precoat layer; the inner layer of the sieve 103 is provided with a coarse mesh for filtrate drainage and support to the outer layer. The bottom of the filter blade 102 is connected with a liquid collecting pipe 104, a nozzle 105 is arranged at the center of the bottom of the filter blade, the nozzle 105 is used as a filtrate discharge port, the nozzle 105 is inserted into the liquid collecting pipe 104 arranged below, and the nozzle 105 and the liquid collecting pipe 104 are sealed by adopting an O-shaped ring. Moreover, each filter vane 102 of the present invention is provided with a nozzle 105, and the provision of the nozzle 105 can increase the drying air flow rate, ensuring that the filter cake is dry and the minimum amount of liquid lost.

In this embodiment, filter blade 102 adopts two-sided filterable design, can obtain great filter area in the jar body less relatively, and filter screen 103 is firm to the support of precoating moreover, and the dismouting clearance is very convenient. The precoat formed on the filter vane 102 provides countless microscopic channels that allow only clear liquid to pass through and the suspended solid particles to be intercepted. During the filtration process, a new filter cake layer is formed by continuously adding the auxiliary agent liquid, so that the materials are substantially filtered through the filter cake layer. The filtrate flows along the framework at the two sides of the filter blade 102 to the nozzle 105 arranged at the bottom, and then the clear liquid flows out through the liquid collecting pipe 104 arranged at the lower part. A new filter cake formed by solid particles in the filtered slurry is maintained on the filter blade 102, and the filtrate enters the filtrate tank 5 through the second filter outlet valve 12b and the filtrate valve 22, wherein the filtrate tank 5 is used for receiving the filtrate of the blade filter; the auxiliary agent pump 6 and the auxiliary agent valve 21 are opened while filtering, and the auxiliary agent is continuously added into the raw material of the filtered pulp.

Furthermore, in order to further ensure the filtering quality of the filtrate, a bag filter is connected to the leaf filter 1.

Furthermore, in the present embodiment, the vane filter 1 is further connected with a spraying device 106, and the spraying device 106 is used for cleaning the filter vane 102; the spraying device 106 is provided with a spraying valve 50, a filter spraying inlet valve and a spraying pipe 107, the spraying pipe 107 is arranged at the upper side inside the filter shell 101 and is arranged at the upper end of the filter blade 102, and the spraying pipe 107 is provided with a plurality of spraying heads 108 in parallel for flushing residual filter cakes on the filter blade 102. The spray valve 50 is connected with a filter spray inlet valve through a spray pipeline, the first vane type filter 1a is connected with a first filter spray inlet valve 51a, and the second vane type filter 1b is connected with a second filter spray inlet valve 51b.

Further, the precoating filter system is provided with a nitrogen valve 30 and a gas release valve 40, and a first filter intake valve 31a is connected to the upper portion of the first vane filter 1a, and a second filter intake valve 31b is connected to the upper portion of the second vane filter 1b. The nitrogen gas valve 30 is connected to the first and second

filter inlet valves

31a and 31b via connecting pipes, and the first and second

filter outlet valves

12a and 12b are connected to the gas release valve 40 via connecting pipes.

In this embodiment, after the filtration is completed, the residual liquid needs to be discharged, and at this time, nitrogen is blown into the second leaf filter 1b through the nitrogen valve 30 and the second filter air inlet valve 31 b; under gas pressure, liquid around the filter blade 102 is forced into the blade until it reaches the bottom of the filter blade 102, and the qualified liquid passes through the second filter outlet valve 12b and the filtrate valve 22 into the filtrate tank 5. The precoating filtering system is also provided with a residual liquid discharge valve 32, and the residual liquid discharge valve 32 is connected with a first filter feed valve 11a and a second filter feed valve 11 b; the residual liquid filtered by the filter vane 102 is discharged into the residual liquid discharge tank or into the raw material tank through the second filter feed valve 11b and the residual liquid discharge valve 32.

In this embodiment, after the completion of the discharge of the residual liquid and before the removal of the filter cake, the filter cake needs to be dried. When the pressure difference in the filter reaches a set pressure difference, oil slurry in the filter is discharged, then nitrogen enters the second vane filter 1b through the nitrogen valve 30 and the second filter air inlet valve 31b, filter cakes on the filter vanes 102 are dried, and the dried nitrogen is discharged through the second filter outlet valve 12b and the gas vent valve 40.

As the filtering time increases, the solid impurities trapped on the blades are increased, the thickness of the filter cake is increased continuously, the filtering resistance of the precoat layer is increased, the pressure in the filter is increased, and the filter cake needs to be removed when the pressure is increased to a certain value. And (3) after ensuring that no pressure exists in the filter and fully drying the filter cake, removing the filter cake. The filter cake, which contains the precoat established before filtration, can usually be removed from the filter blades 102 by means of a rotating, shaking, beating or hammering action. And after the filter cake removing process is finished, the precoating work is carried out again.

Further, in this embodiment, an oscillator assembly 109 is connected to the upper end of the vane filter 1, the oscillator assembly 109 is provided with an oscillator 110 and an oscillator transmission shaft 111, the oscillator 110 is installed outside the filter housing 101, and the oscillator 110 is connected to the upper end of the filter blades 102 through the oscillator transmission shaft 111 and also connected to the gasket between the filter blades 102. For the colloid or asphaltene which is not easy to strip in the filter cake generated after the oil slurry is filtered, the oscillator assembly 109 is used as a filter cake discharging mechanism, and the whole blade combination part is vibrated by the vibrator 110 in the embodiment, so that the filter cake is released under the assistance of gravity. The shaker drive shaft 111 passes through a rubber membrane on the filter blade 102 and then makes an "O" seal to ensure that the called-up vibration energy is fully applied to the filter cake unloading.

In this embodiment, the slag discharge cart 2 is disposed at the bottom of the vane filter, and after the filter cake is discharged, the filter cake is discharged through a slag discharge valve at the bottom of the container with an inverted circular truncated cone structure at the bottom of the filter, and enters the slag discharge cart 2 for treatment or recovery.

Further, in this embodiment, the second filter feeding valve 11b is connected to a filter feeding port provided at the bottom of the second vane filter 1b, and a feeding baffle 112 is provided at the filter feeding port. The feed baffle 112 acts as a buffer for the material, preventing the feed from directly eroding the filter vanes 102 and allowing the feed to rise gradually from the bottom of the filter upwards, thereby ensuring that the solids in the feed remain suspended and are not disturbed in the formation of a filter cake on the filter vanes 102.

Furthermore, in the present embodiment, the bottom of the leaf filter 1 is of an inverted truncated cone structure, the intersection angle of the oblique edge of the bottom of the leaf filter and the horizontal plane is 60 °, and the optimal discharging effect can be maintained by setting the bottom of the inverted truncated cone structure to 60 °.

In this embodiment, before the precoating operation is performed again after the filter cake is removed, the filter vane 102 needs to be cleaned to remove the filter cake residues adhered to the filter vane 102, the filter vane 102 is cleaned by the spraying device 106, and the spraying device 106 uses a special high impact force to spray the whole medium surface. The rinsing liquid required by the spray device 106 may be filtered cleaning liquid from the precoat tank 4 for blade cleaning by turning on the precoat circulating pump 7, the spray valve 50 and the second filter spray inlet valve 51b.

Furthermore, the automatic switching time interval of the blade type filter is not less than 5 hours.

Furthermore, the present embodiment is described in detail by taking oil slurry filtration as an example, but the precoating filtration system of the present invention is not limited to be applied to the field of oil slurry filtration, and can also be applied to the fields of coal indirect liquefaction Fischer-Tropsch wax (paraffin) filtration, coal tar filtration, and dilute ammonium sulfate (acrylonitrile) filtration. When the precoat filter system is applied to the filtration of other filter media, the corresponding process parameters can be changed according to the actual needs in the field, for example, the pitch and the number of the settings of the corresponding filter blades are modified.

The working principle of the invention is as follows: the precoating filtering system of the invention sequentially carries out preparation of a precoating agent, precoating of filter blades, oil slurry filtering, residual liquid discharging, filter cake drying, filter cake discharging and filter blade cleaning, thereby carrying out long-period continuous operation of oil slurry filtering. The invention has compact structure, small floor area, large filtration area and less solid content in the filtered oil slurry. The blade type filter can realize full-automatic operation, the processes can be automatically completed in a linkage manner, the performance is safe and reliable, and the later maintenance cost is low.

It is to be understood that in the description of the present invention, the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Further, in the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

However, the above description is only exemplary of the present invention, and the scope of the present invention should not be limited thereby, and the replacement of the equivalent components or the equivalent changes and modifications made according to the protection scope of the present invention should be covered by the claims of the present invention.

Claims

1. The precoating filtering system capable of continuously running in a long period comprises a precoating unit, an auxiliary agent unit and a filtering unit, and is characterized in that the precoating unit comprises a precoating feeding device, a precoating tank and a precoating circulating pump, the auxiliary agent unit comprises an auxiliary agent feeding device, an auxiliary agent tank and an auxiliary agent pump, and the filtering unit comprises a blade type filter, a slag discharge trolley and a filtrate tank; the precoating filtering system is also provided with an oil slurry raw material valve, the blade type filter is provided with a filter shell and filter blades, and the filter blades are provided with a plurality of groups and are arranged in the filter shell.

2. The system of claim 1, wherein a filter feed valve and a filter outlet valve are connected to the lower part of the vane filter, the precoating feed device is connected to the upper end of the precoating tank, the lower part of the precoating tank is connected to the filter feed valve through the precoating circulating pump and a precoating pipe, the precoating pipe is connected to the precoating valve, and the filter outlet valve is connected to the precoating tank through a connecting pipe and a precoating circulating valve; the auxiliary agent feeding device is connected with the upper end of the auxiliary agent tank, the lower portion of the auxiliary agent tank is connected with the auxiliary agent pump, the auxiliary agent pump is connected with the oil slurry raw material valve through an auxiliary agent valve and a connecting pipeline, the oil slurry raw material valve is connected with the filter feeding valve through a connecting pipeline, the filter outlet valve is connected with the filtrate tank through a connecting pipeline and a filtrate valve, and the residue discharge trolley is arranged at the bottom of the blade type filter.

3. A long period continuous operation precoating filter system according to claim 2, wherein said precoating filter system is further provided with a nitrogen valve and a gas release valve, the upper part of said leaf filter is connected with a filter inlet valve, said nitrogen valve is connected with said filter inlet valve through a connecting pipe, and said filter outlet valve is connected with said gas release valve through a connecting pipe.

4. The precoating filter system capable of long-period continuous operation according to claim 3, wherein a plurality of groups of filter blades are vertically arranged in the filter housing, a space is arranged between adjacent filter blades, a filter screen is covered on the filtering surface of each filter blade and consists of a plurality of layers of stainless steel wire meshes, and a precoating layer is supported and connected on each filter screen; the bottom of the filter blade is connected with a liquid collecting pipe, a nozzle is arranged at the center of the bottom of the filter blade, and the nozzle is inserted into the liquid collecting pipe arranged below the nozzle.

5. The system of claim 4, wherein the distance between adjacent filter blades is 30-100mm, the blade filter is further connected with a spray device, the spray device is provided with a spray valve, a filter spray inlet valve and a spray header, the spray valve is connected with the filter spray inlet valve through a spray pipeline, the spray header is arranged in the filter shell and arranged at the upper end of the filter blades, and a plurality of spray headers are arranged in parallel.

6. A long cycle continuous precoated filter system according to claim 5, wherein said filter feed valve is connected to a filter feed provided at the bottom of said leaf filter, said filter feed being provided with feed baffles; the upper end of the blade type filter is connected with an oscillator assembly, the oscillator assembly is provided with an oscillator and an oscillator transmission shaft, the oscillator is installed on the outer side of the filter shell, and the oscillator is connected with the upper end of the filter blade through the oscillator transmission shaft.

7. The long term continuous service precoated filter system according to claim 6, wherein the base of the leaf filter is of a rounded truncated configuration, and the angle of the oblique edge of the leaf filter base to the horizontal is 60 °.

8. A long cycle continuous precoated filter system according to claim 7, wherein there are two leaf filters in the filtration unit, a first leaf filter and a second leaf filter, respectively, to which there are attached bag filters.

9. A long term continuous operation precoated filtration system according to claim 8, wherein the material of the precoated powder used in the precoating unit is diatomaceous earth, cellulose powder or fuller's earth, and the auxiliary powder used in the auxiliary unit is the same material, same grade, as the precoated powder.

10. The system of claim 1 or 9, wherein the precoating feeding device and the auxiliary feeding device are both provided with dust removing devices, the inside of the precoating tank and the inside of the auxiliary tank are both provided with stirring devices, the tops of the precoating tank and the auxiliary tank are both provided with feeding orifices, and at least one precoating circulating pump and at least one auxiliary pump are both provided.