CN117654786A - Liquid-liquid horizontal screw machine and use method thereof - Google Patents

Abstract

The invention belongs to the technical field of oil-containing waste treatment, and particularly relates to a liquid-liquid horizontal screw machine and a use method thereof. The liquid-liquid horizontal screw machine comprises: a rotary drum, a pushing screw; a separation channel is formed between the inner wall of the rotary drum and the outer wall of the pushing spiral; the rear end of the separation channel is provided with a liquid outlet, and the front end of the separation channel is provided with a slag outlet; a liquid baffle is arranged in the liquid outlet, and a baffle is arranged at the front end of the liquid baffle; the space between the inner end part of the liquid baffle and the inner wall of the liquid outlet forms a first liquid outlet, the space between the outer end part of the baffle and the outer wall of the liquid outlet forms a second liquid outlet, and the first liquid outlet and the second liquid outlet are in fluid communication to form a baffling channel. According to the invention, a baffling channel is formed at the liquid outlet of the horizontal screw machine, and a proper liquid baffle plate size and a proper centrifugal machine rotating speed are configured according to the components of materials, so that the separation of an oil-water emulsifying layer in an oil sludge mixture from sludge or the separation of the oil-water emulsifying layer in dirty oil from oil is realized.

Description

Liquid-liquid horizontal screw machine and use method thereof

Technical Field

The invention belongs to the technical field of oil-containing waste treatment, and particularly relates to a liquid-liquid horizontal screw machine and a use method thereof.

Background

The oily sludge, which is commonly referred to as oil sludge for short, refers to oily solid waste generated in various links of petroleum exploitation, processing, storage and transportation and refining. Such as waste oil-based mud and rock debris generated in the oil exploitation link, ground oil sludge generated by crude oil gathering, breaking, leaking and leaking, aged oil and clear tank oil sludge generated in the crude oil storage link, scum oil sludge generated in the sewage treatment link and the like. Because the oil sludge contains some toxic and harmful substances, the oil sludge is classified into hazardous wastes of the classes of waste mineral oil and mineral oil-containing wastes in HW08 of the national hazardous waste directory. According to measurement and calculation, the oil content in the oil-containing sludge is up to about 5% -45%, the non-compliance treatment can pollute the environment, and the direct incineration and landfill treatment can cause the waste of petroleum resources, so that the oil-containing sludge is subjected to harmless treatment and residual oil recovery by adopting a proper technical means, and certain economic benefits can be generated, and obvious environmental benefits and social benefits can be brought.

The chemical heat washing process is a conventional process in the field of oil sludge treatment and disposal, generally, water is mixed with the oil sludge according to a certain proportion for tempering, a special chemical heat washing agent is added after the mixture is heated to a certain temperature, an oil phase and a solid are peeled off by utilizing the action mechanisms of wetting inversion, emulsification cleaning and the like of the agent, and then the oil phase and the solid are mechanically separated by a centrifugal machine, so that the aim of three-phase separation of oil, water and sludge is fulfilled, and the solid phase oil content after cleaning is reduced to a certain index, so that the aim of harmless disposal is fulfilled; and recycling petroleum in the oil sludge. As the oil field is mined into the middle and later stages, a large amount of chemical agents such as polymers are often added in the mining process to improve the recovery ratio, so that the generated oily sludge also contains polymers, and oil molecules are adhered to the branched chains of the macromolecular polymers to form oily polymers, and the density of the oily polymers is close to that of water. The oil sludge also contains clay-like fine sludge with the density close to that of water, and the clay-like fine sludge is adsorbed with oil molecules under the stratum to form oil-containing fine sludge with the density close to that of water. Thus, the direction of these oily polymers and oily sludge determines the treatment effect of the separation process.

The above-mentioned mechanical separation using a centrifuge is generally separation using a conventional decanter centrifuge, but the inventors found that the following problems exist:

(1) The components of the oily sludge from different batches and different sources are greatly different, the thicknesses of annular layers formed by the components in the centrifugal machine are different, and the liquid discharge port and the slag discharge port of the conventional horizontal decanter centrifuge are in a straight-line form and are difficult to adjust, so that the separation of solid and oil phases is difficult to realize thoroughly.

(2) The macromolecular polymer with the density close to that of water and the fine mud are formed between the solid annular layer and the water annular layer or between the water annular layer and the oil annular layer in the conventional horizontal decanter centrifuge. The solid-liquid separation process of the conventional horizontal decanter centrifuge can lead to the discharge of part of oily polymer and oily fine mud from a slag discharge port, so that the oil content in the separated solid phase is higher. And meanwhile, part of fine mud is discharged from a liquid outlet, so that the ash content in the recovered oil phase is higher.

The dirty oil consists of an oil phase, a water phase, solids and a part of polymers which are extracted with oil, and the direct added value of the dirty oil is low. The aim of the dirty oil purification is to lower the water content and ash content of the oil product to a certain index, thereby obtaining purer oil product and improving the added value of the purer oil product. The common centrifugal machine for purifying dirty oil is a disk centrifugal machine, and the delamination of solids, water and oil phases in the dirty oil is realized under the high centrifugal force generated by high rotation speed, and the dirty oil is discharged from a different outlet. The disc centrifuge adopted for the dirty oil with larger viscosity or smaller oil-water density difference and the dirty oil with higher solid content and polymer content has certain problems: the channels among discs in the disc centrifugal machine are relatively narrow, and when the disc centrifugal machine is used for treating dirty oil with high viscosity or high solid content or aggregation, the channels are often easy to be blocked, so that the operation stability is poor, and the disc centrifugal machine is stopped for clearing blockage once about three days.

The present invention has been made to solve the above problems.

Disclosure of Invention

The first aspect of the invention provides a liquid-liquid horizontal screw machine, comprising: a rotary drum 1, a pushing spiral positioned in the rotary drum 1; the power system is used for controlling the rotary drum 1 and the pushing spiral to rotate;

the drum 1 comprises: a cylindrical section at the rear end, a conical section at the front end;

a separation channel is formed between the inner wall of the rotary drum 1 and the outer wall of the pushing spiral;

the rear end of the separation channel is provided with a liquid outlet 5, and the front end of the separation channel is provided with a slag discharging port 6;

a liquid baffle plate 8 is arranged in the liquid outlet 5, and a baffle plate 9 is arranged at the front end of the liquid baffle plate 8;

the liquid baffle 8 has an inner end close to the central axis of the pushing screw and an outer end far from the central axis of the pushing screw, and the baffle 9 has an inner end close to the central axis of the pushing screw and an outer end far from the central axis of the pushing screw;

the liquid outlet 5 is provided with an inner wall close to the central axis of the pushing screw and an outer wall far away from the central axis of the pushing screw;

the space between the inner end part of the liquid baffle 8 and the inner wall of the liquid outlet 5 forms a first liquid outlet 5-1, the space between the outer end part of the baffle 9 and the outer wall of the liquid outlet 5 forms a second liquid outlet 5-2, and the first liquid outlet 5-1 and the second liquid outlet 5-2 are in fluid communication to form a baffling channel.

The terms "front end" and "rear end" are relative terms and do not constitute a limitation on the structure of the present invention.

Preferably, the inner end of the liquid baffle 8 is in a circular arc shape, and the circle where the circular arc is located takes the central axis of the pushing spiral as the center of a circle.

Preferably, the number of the liquid baffle plates 8 is several, and the liquid baffle plates are circumferentially and uniformly distributed in the liquid outlet 5;

the number of baffles 9 is the same as the number of baffles 8.

Preferably, the liquid baffle 8 and the baffle 9 are arranged in parallel.

Preferably, the liquid baffle 8 and the baffle 9 are perpendicular to the central axis of the pushing screw.

Preferably, the liquid baffle 8 is a circular plate with a flow hole, and the baffle 9 is a hoof-shaped plate with an inner notch.

Of course, the liquid blocking plate 8 and the baffle 9 may have other shapes, as long as the first liquid discharge port 5-1 and the second liquid discharge port 5-2 are formed at the liquid discharge port 5.

Preferably, the pushing screw comprises: the device comprises a spiral core tube 2, a plurality of spiral blades 3 arranged on the outer wall of the spiral core tube 3 and a material distributing opening 4 positioned on the spiral core tube 2.

Preferably, a drum end cover 7 is arranged at the rear end of the drum 1, and the liquid drain port 5 is arranged on the drum end cover 7.

A second aspect of the present invention provides a method for using the liquid-liquid horizontal screw machine according to any one of the first aspect, wherein the method for using the liquid-liquid horizontal screw machine includes one of the following modes:

mode one:

the liquid-liquid horizontal screw machine is used for separating oil-containing sludge slurry after tempering:

the oil-containing sludge slurry after tempering contains mud, water, oil-water emulsifying substances and oil, the height of the first liquid outlet 5-1 is regulated and controlled by adjusting the liquid baffle 8, the liquid-liquid horizontal screw machine is started, the power system is regulated and controlled, the oil-containing sludge slurry after tempering is added into the pushing screw, so that mud and part of water in the oil-containing sludge slurry after tempering are discharged from the slag outlet 6, and the oil, the oil-water emulsifying substances and the rest of water in the oil-containing sludge are discharged from the liquid outlet 5;

mode two:

the liquid-liquid horizontal screw machine is used for purifying the modified dirty oil:

the modified dirty oil contains water, oil and oil-water emulsified substances, the height of the first liquid outlet 5-1 is regulated and controlled by adjusting the liquid baffle plate 8, the liquid-liquid horizontal screw machine is started, the power system is regulated and controlled, the modified dirty oil is added into the pushing screw, so that the oil in the dirty oil is discharged from the liquid outlet 5, and the water and oil-water emulsified substances in the dirty oil are discharged from the slag discharge port 6;

wherein the height of the first liquid outlet 5-1 in the first mode is larger than the height of the first liquid outlet 5-1 in the second mode;

the rotating speed of the rotary drum 1 in the first mode is smaller than that of the rotary drum 1 in the second mode;

the rotating speed of the pushing spiral in the first mode is smaller than that of the pushing spiral in the second mode.

Preferably, the power system comprises: a main motor for controlling the rotating speed of the rotary drum 1 and a secondary motor for controlling the rotating speed of the pushing spiral;

the mode of regulating the power system is as follows: regulating and controlling the rotating speed of the main motor and the differential rotating speed of the main motor and the auxiliary motor.

The power system of the invention comprises a centrifuge, and the using process is as follows: the centrifuge was started before feeding. The centrifugal machine has three key parameters, namely the rotation speed of a main motor, the rotation speed of an auxiliary motor and the differential speed. Two of these three parameters need to be set, the third being auto-association. The main motor rotating speed and differential speed are generally set, then after the centrifuge is started to reach a preset value, feeding is performed, namely no-load stable operation is performed firstly, feeding is performed at low flow rate, and the flow rate is regulated to a required value.

The above oil-water emulsion layer comprises: an oleaginous polymer and oleaginous puree.

The technical proposal can be freely combined on the premise of no contradiction.

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

1. the innovation point of the invention is that: a baffling channel is formed at the liquid outlet 5 of the horizontal screw machine through a liquid baffle plate 8 and a baffle plate 9, so that the separation of an oil-water emulsion layer in the oil sludge mixture from sludge or the separation of the oil-water emulsion layer in dirty oil from oil is realized.

In the invention, the separated components overflow out through the second liquid outlet 5-2 due to the baffling channel formed by the shielding of the liquid baffle plate 8, so that the retention time of materials in the separation channel, especially the retention time of liquid, is greatly prolonged, and the good separation of the oil-water emulsion layer and the target product can be controlled.

When the baffle channel is not arranged, the liquid outlet is in a straight-line mode, liquid in the separation channel is directly sprayed out from the liquid outlet 5 under the action of centrifugal force in the horizontal screw machine, and a target product cannot be well separated from the oil-water emulsion layer.

2. Specifically, the key point of the invention is that: according to the material components to be separated, the separation of the oil-water emulsion layer and the mud in the oil-mud mixture or the separation of the oil-water emulsion layer and the oil in the dirty oil can be realized by adjusting the height of the first liquid outlet 5-1 formed by the liquid baffle plate 8 and matching with the rotating speed and the differential rotating speed of the centrifugal machine in the horizontal screw machine.

Drawings

Fig. 1 is a schematic diagram of a liquid-liquid horizontal screw machine according to an embodiment.

Fig. 2 is a schematic diagram showing the distribution of the liquid drain ports 5 on the drum end cover 7.

Fig. 3 is a schematic view of the structure of the liquid baffle 8 when it is a circular plate having a flow hole.

Fig. 4 is a schematic view of the structure of the baffle plate 9 when it is a shoe plate with an inner notch.

Fig. 5 is a schematic illustration of sizing of the baffle 8.

FIG. 6 is a photograph of the separated material of comparative example 1.

List of reference numerals:

1. the device comprises a rotary drum, a spiral core tube, a spiral blade, a material distributing port, a liquid discharging port, a first liquid discharging port, a second liquid discharging port, a slag discharging port, a rotary drum end cover, a liquid blocking plate and a baffle.

Detailed Description

The present invention will be described in further detail with reference to examples.

It will be appreciated by those skilled in the art that the following examples are illustrative of the present invention and should not be construed as limiting the scope of the invention. The specific techniques or conditions are not identified in the examples and are performed according to techniques or conditions described in the literature in this field or according to the product specifications. The materials or equipment used are conventional products available from commercial sources, not identified to the manufacturer.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless expressly stated otherwise, as understood by those skilled in the art. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "coupled" to another element, it can be directly coupled to the other element or intervening elements may also be present. Further, "coupled" as used herein may include wirelessly coupled.

In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more. The orientation or state relationship indicated by the terms "inner", "upper", "lower", etc. are orientation or state relationship based on the drawings, are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the invention.

In the description of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "mounted," "coupled," and "provided" are to be construed broadly, and may be, for example, fixedly coupled, detachably coupled, or integrally coupled; can be mechanically or electrically coupled; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present invention is understood by those of ordinary skill in the art according to the specific circumstances.

It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The working principle of the horizontal screw machine is as follows:

the front end of the spiral core tube is provided with a feed inlet, and the rear end is closed. Of course, some horizontal screws feed from the rear end and the front end is closed. When the slurry to be separated is conveyed into the spiral core pipe, the slurry enters a separation channel between the rotary drum and the pushing spiral through evenly distributed material distributing openings 4, solid phase particles with higher density than liquid phase rapidly settle to the inner wall of the rotary drum 1 under the action of centrifugal force, the spiral blades 3 of the pushing spiral push the solid phase deposited on the inner wall of the rotary drum 1 to the front end of the separation channel to be discharged through a slag discharging opening 6, and separated clear liquid flows out from a liquid discharging opening 5 at the rear end of the separation channel.

A liquid-liquid horizontal screw machine for innocuous cleaning of oily sludge and purification of dirty oil comprises:

the inside of the rotary drum 1 is coaxially provided with a pushing spiral, the rear part of the rotary drum 1 is connected with a rotary drum end cover 7, and the rotary drum 1 comprises a cylindrical section positioned at the rear end and a conical section positioned at the front end;

the pushing screw comprises: the spiral core tube 2 is provided with a plurality of spiral blades on the outer wall of the spiral core tube 3, and a material distributing opening 4 positioned on the spiral core tube 2;

the material distribution opening 4 enables the materials in the spiral core tube 2 of the pushing spiral to be uniformly distributed in the separation channel;

a separation channel is formed between the inner wall of the rotary drum 1 and the outer wall of the pushing spiral;

the front end of the separation channel is provided with a slag discharge port 6, and components with higher density in the separated medium are discharged from the slag discharge port 6;

the rear end of the separation channel is provided with a liquid outlet 5, and the components with smaller density in the separated medium are discharged from the liquid outlet 5;

the number of the liquid outlets 5 is four, and the liquid outlets are circumferentially and uniformly distributed on the rotary drum end cover 7;

inside the liquid discharge port 5, a liquid blocking plate 8 and a baffle 9 are provided. The space between the inner end part of the liquid baffle 8 and the inner wall of the liquid outlet 5 forms a first liquid outlet 5-1, the space between the outer end part of the baffle 9 and the outer wall of the liquid outlet 5 forms a second liquid outlet 5-2, and the first liquid outlet 5-1 and the second liquid outlet 5-2 are in fluid communication to form a baffling channel.

Preferably, the liquid baffle 8 is a circular plate having a flow hole. The first liquid outlet 5-1 is arranged at the position of the flow hole of the liquid baffle plate 8 and is close to the central axis of the pushing screw, so that the components with smaller inner layer density in the separation channel are discharged from the first liquid outlet 5-1.

Preferably, the baffle 9 is a shoe plate with an internal notch.

The inner notch is a second liquid outlet 5-2 which is far away from the central axis of the pushing spiral, so that the first liquid outlet 5-1 and the second liquid outlet 5-2 are in fluid communication to form a baffling channel.

Specifically, the liquid baffle 8 and the baffle 9 are coaxially installed (i.e. when the liquid baffle 8 is installed, two circle centers of the circumscribed circle of the liquid baffle 8 and the circumscribed circle of the baffle 9 are coaxial), the shared screw holes are fixed, the baffle 9 is installed close to the front end and is separated from the liquid baffle 8 by a certain distance, and the two functions form an L-shaped liquid baffling channel.

Fig. 1 is a schematic structural diagram of a liquid-liquid horizontal screw machine according to an embodiment.

Fig. 2 is a schematic distribution view of the liquid drain ports 5 on the drum end cover 7.

Fig. 3 is a schematic view of the structure of the liquid baffle 8 when it is a circular plate having flow holes.

Fig. 4 is a schematic view of the structure of the baffle plate 9 when it is a shoe plate with an inner notch. The shoe plate includes: a circular plate body and a semicircular notch thereon. The semicircular part is left on the circular plate main body to serve as a flow blocking part. The semicircular notch part is a second liquid outlet 5-2.

Fig. 5 is a schematic illustration of sizing of the baffle 8.

The flow rate of the light liquid phase discharged from the liquid outlet 5 is regulated by changing the liquid baffle plates with different flow areas, and the light liquid phase is discharged through a baffling channel between the liquid baffle plate 8 and the baffle plate 9. The other components are discharged from the slag discharging port 6. According to the characteristics of the components of the separated materials, the liquid baffle plate 8 with proper size is configured, so that the selective separation of the components of the annular layers with different densities is realized.

The liquid baffle plates 8 are replaceable, and the areas of through holes (namely the areas of the first liquid drain holes 5-1) of different liquid baffle plates 8 are different. According to the invention, the liquid baffle plate 8 with proper through-flow hole area can be configured according to the characteristics of the components of the separated materials, so that the purpose of selectively separating the components with different densities is realized. The through holes of the liquid baffle plate 8 are as follows: and the intersection part of the round liquid baffle plate and a circle taking the central axis of the pushing spiral as the center of a circle and R as the radius. The size of R determines the size of the through-flow hole area of the liquid baffle 8 (as shown in fig. 4). I.e. different R values characterize the baffles 8 with different through-flow aperture areas.

When the horizontal screw machine is used for harmless cleaning of oil-containing sludge, the liquid baffle 8 with larger R is adopted, so that the first liquid outlet 5-1 is larger in height, and proper centrifugal machine rotating speed (the phenomenon that oil-containing polymer and oil-containing fine sludge enter a solid-phase ring layer due to excessive centrifugal force) and differential rotating speed are set, so that the mud water is discharged from a slag outlet, and the oil water is discharged from the liquid outlet. The muddy water enters a secondary cleaning flow and is subjected to solid-liquid separation by adopting a conventional centrifuge; oil-water separation is carried out on the oil water, and the oil phase is recycled.

When the horizontal decanter centrifuge is used for purifying dirty oil, the liquid baffle 8 with smaller R is adopted, so that the first liquid outlet 5-1 is smaller in height, and proper rotational speed (the phenomenon that oil-containing polymer and oil-containing fine mud enter an oil phase annular layer due to too small centrifugal force) and differential rotational speed are set, so that the innermost oil phase annular layer is discharged from the liquid outlet 5, and the residual liquid phase is discharged from the slag outlet 6.

The using method of the horizontal liquid screw machine comprises the following steps:

mode one:

the liquid-liquid horizontal screw machine is used for separating oil-containing sludge slurry after tempering:

the oil-containing sludge after tempering contains mud, oil-water emulsified materials, water and oil, the height of the first liquid outlet 5-1) is regulated and controlled by adjusting the liquid baffle 8, the liquid-liquid horizontal screw machine is started, the power system is regulated and controlled, the oil-containing sludge after tempering is conveyed into the pushing screw, enters a separation channel between the rotary drum 1 and the pushing screw through the material distributing port 4, forms annular layers with different densities under the action of centrifugal force, the component mud with higher density is settled to the inner wall of the rotary drum 1 to form an outermost annular layer, and the water, the oil-water emulsified materials and the oil sequentially form an inner annular layer (the inner annular layer is from outside to inside and is respectively: a water layer, an oil-water emulsion layer and an oil layer), wherein sludge and part of water in the oil-containing sludge are discharged from the slag discharge port 6, and oil-water emulsion substances in the oil-containing sludge and the rest of water are discharged from the liquid discharge port 5;

mode two:

the liquid-liquid horizontal screw machine is used for purifying the modified dirty oil:

the modified dirty oil contains water, oil and oil-water emulsified substances, the height of the first liquid outlet 5-1 is regulated and controlled by regulating the liquid baffle plate 8, the power system is regulated and controlled, the modified dirty oil is conveyed into the pushing screw, enters a separation channel between the rotary drum 1 and the pushing screw through the material distributing port 4, forms annular layers with different densities under the action of centrifugal force, and sequentially comprises a water layer, an oil-water emulsified layer and an oil layer from the outer layer to the inner layer, then the oil layer is discharged from the liquid outlet 5, and the water layer and the oil-water emulsified layer are discharged from the slag discharging port 6;

wherein the height of the first liquid outlet 5-1 in the first mode is larger than the height of the first liquid outlet 5-1 in the second mode;

the rotating speed of the rotary drum 1 in the first mode is smaller than that of the rotary drum 1 in the second mode;

the rotating speed of the pushing spiral in the first mode is smaller than that of the pushing spiral in the second mode.

The above oil-water emulsion layer comprises: an oleaginous polymer and oleaginous puree.

The oil-containing sludge after tempering is the oil-containing sludge after chemical heat washing agent treatment, and is characterized by containing oil-water emulsifying substances.

The modified dirty oil is treated by a chemical heat washing agent and is characterized by containing oil-water emulsifying substances.

Example 1

Taking scum oil sludge generated by a sewage treatment system of a certain oil field joint station of Liaoning brocade, wherein the scum oil sludge is gel-like sticky substance with brownish black color, the oil content is measured to be 12wt% on average, and the water content is measured to be 80wt% on average; and (3) carrying out quenching and tempering treatment at 60 ℃ by using a chemical hot washing process, wherein the moisture content after quenching and tempering is about 95%, and mixing and stirring after adding a certain amount of chemical cleaning agent. All the treated oil-water-sludge mixture enters a liquid-liquid horizontal decanter centrifuge for separation, wherein the diameter of a centrifuge drum is 420mm, a liquid baffle plate is of a type with R=130mm, the rotating speed of a main motor of the centrifuge is 1550 rpm, and the differential rotating speed is 10 rpm. After the stable operation, the flow ratio of the mud-water mixture discharged from the slag discharge port to the oil-water mixture discharged from the liquid discharge port is about 2:3. The mud water mixture enters a secondary cleaning flow for tempering and dosing treatment (water tempering and dosing mixing according to the proportion of 1:1), then enters an LW420 two-phase horizontal screw centrifuge for solid-liquid separation, the rotational speed of a main motor of the centrifuge is set to be not less than 2000 revolutions per minute, the differential rotational speed is 12 revolutions per minute, the residual oil content of the separated mud is measured to be 1.1wt%, and the separated mud accords with the national standard of less than 2 wt%. And (3) carrying out subsequent oil-water separation and dirty oil purification processes on the oil-water mixture discharged from the liquid outlet of the liquid-liquid horizontal screw machine to recycle oil.

Example 2

Taking dirty oil in an oil separation tank of a sewage treatment system of a middle petrochemical plant, wherein the dirty oil is a brown-black sticky substance, the measured average value of the oil content is 55wt%, and the measured average value of the water content is 40wt%; the dirty oil is pretreated by adopting a chemical demulsification method, namely 80ppm demulsifier is added at the temperature of 75 ℃, the rotation speed of a mixing stirring paddle is set to 20 revolutions per minute, and the mixture is stirred for 5 minutes. All the treated oil-water-sludge mixture enters a liquid-liquid horizontal decanter centrifuge for separation, the diameter of a centrifuge drum is 420mm, a liquid baffle plate is of a type with R=120mm, the rotating speed of a main motor of the centrifuge is 2500 rpm, and the differential rotating speed is 8 rpm. The flow ratio of the mixture discharged from the slag discharge port to the mixture discharged from the liquid discharge port after the stable operation is about 3:2. The mixture discharged from the slag discharging port is subjected to oil-water separation, the sewage at the lower layer enters a sewage treatment system, and the sewage oil at the upper layer returns to a sewage oil pool for further treatment; the mixture discharged from the liquid outlet is the purified oil, the residual water phase quantity in the oil phase is 1.5% and the residual ash quantity is 0.8% as measured by sampling analysis, so that the index requirement that the water content of the recovered oil is less than 2% and the ash content is less than 1% is satisfied.

Comparative example 1

The same treated oil-water-mud mixture materials in the embodiment 1 are used, an LW420 two-phase horizontal decanter centrifuge is adopted, a secondary cleaning process is adopted, in order to ensure the effect of solid-liquid separation, the primary horizontal decanter centrifuge is provided with a main motor rotating speed of not less than 2000 revolutions per minute (the main motor rotating speed is the same as that in the embodiment 1), the differential rotating speed is 12 revolutions per minute, separated mud is discharged from a slag discharging port to enter a secondary dosing mixing unit, water is added for tempering according to the proportion of 1:1, dosing is carried out, mixed slurry enters the secondary horizontal decanter centrifuge, the parameters of the mixed slurry are set to be the same as the primary horizontal decanter centrifuge, and the separated mud is conveyed to the outside of equipment through a spiral mud conveyer from the slag discharging port. Oil and water mixtures at liquid discharge ports of the primary horizontal decanter centrifuges and the secondary horizontal decanter centrifuges are used for recovering oil products through an oil-water separation unit, and the residual sewage enters a sewage treatment system. The mud separated from the second-stage horizontal screw was black and its residual oil content was measured to be 4wt%.

FIG. 6 is a photograph of the separated material of comparative example 1. The results show that: the separated mud was solid black and its residual oil content was measured to be 4wt% with oil content exceeding the standard.

Claims (10)

1. A liquid-liquid horizontal screw machine, characterized in that it comprises: the rotary drum (1) is positioned in the rotary drum (1) and is provided with a pushing spiral, and a power system for controlling the rotary drum (1) and the pushing spiral to rotate is arranged;

wherein the drum (1) comprises: a cylindrical section at the rear end, a conical section at the front end;

a separation channel is formed between the inner wall of the rotary drum (1) and the outer wall of the pushing spiral;

the rear end of the separation channel is provided with a liquid outlet (5), and the front end of the separation channel is provided with a slag outlet (6);

a liquid baffle (8) is arranged in the liquid outlet (5), and a baffle (9) is arranged at the rear end of the liquid baffle (8);

the liquid baffle (8) is provided with an inner end part close to the central axis of the pushing spiral and an outer end part far away from the central axis of the pushing spiral, and the baffle (9) is provided with an inner end part close to the central axis of the pushing spiral and an outer end part far away from the central axis of the pushing spiral;

the liquid outlet (5) is provided with an inner wall close to the central axis of the pushing spiral and an outer wall far away from the central axis of the pushing spiral;

the space between the inner end part of the liquid baffle (8) and the inner wall of the liquid outlet (5) forms a first liquid outlet (5-1), the space between the outer end part of the baffle (9) and the outer wall of the liquid outlet (5) forms a second liquid outlet (5-2), and the first liquid outlet (5-1) and the second liquid outlet (5-2) are in fluid communication to form a baffling channel.

2. The liquid-liquid horizontal screw machine according to claim 1, wherein the inner end of the liquid baffle (8) is in a circular arc shape, and the circle where the circular arc is located takes the central axis of the pushing screw as the center of a circle.

3. The liquid-liquid horizontal screw machine according to claim 1, wherein the number of the liquid baffle plates (8) is a plurality, and the liquid baffle plates are circumferentially and uniformly distributed in the liquid outlet (5);

the number of the baffles (9) is the same as the number of the liquid baffle plates (8).

4. The liquid-liquid horizontal screw machine according to claim 1, characterized in that the liquid baffle (8) and the baffle (9) are arranged in parallel.

5. The liquid-liquid horizontal screw machine according to claim 1, characterized in that the liquid baffle (8) and the baffle (9) are perpendicular to the pushing screw central axis.

6. The liquid horizontal screw machine according to claim 1, characterized in that the liquid baffle (8) is a circular plate with flow holes, and the baffle (9) is a hoof-shaped plate with internal notches.

7. The liquid horizontal screw machine of claim 1, wherein the pushing screw comprises: the device comprises a spiral core tube (2), a plurality of spiral blades (3) arranged on the outer wall of the spiral core tube (3) and a material distributing opening (4) arranged on the spiral core tube (2).

8. The liquid-liquid horizontal screw machine according to claim 1, characterized in that a drum end cover (7) is arranged at the rear end of the drum (1), and the liquid drain port (5) is arranged on the drum end cover (7).

9. A method of using a liquid-liquid horizontal screw machine according to any one of claims 1 to 8, comprising one of the following:

mode one:

the liquid-liquid horizontal screw machine is used for separating oil-containing sludge slurry after tempering:

the oil-containing sludge slurry after tempering contains sludge, water, oil-water emulsifying substances and oil, the height of the first liquid outlet (5-1) is regulated and controlled by adjusting the liquid baffle (8), the liquid-liquid horizontal screw machine is started, the power system is regulated and controlled, the oil-containing sludge slurry after tempering is added into the pushing screw, so that the sludge and part of water in the oil-containing sludge slurry after tempering are discharged from the slag outlet (6), and the oil, the oil-water emulsifying substances and the rest of water in the oil-containing sludge are discharged from the liquid outlet (5);

mode two:

the liquid-liquid horizontal screw machine is used for purifying the modified dirty oil:

the modified dirty oil contains water, oil and oil-water emulsified substances, the height of the first liquid outlet (5-1) is regulated and controlled by adjusting the liquid baffle (8), the liquid-liquid horizontal screw machine is started, the power system is regulated and controlled, the modified dirty oil is added into the pushing screw, so that the oil in the dirty oil is discharged from the liquid outlet (5), and the water and oil-water emulsified substances are discharged from the slag outlet (6);

wherein the height of the first liquid outlet (5-1) in the first mode is larger than the height of the first liquid outlet (5-1) in the second mode;

the rotating speed of the middle rotary drum (1) in the first mode is smaller than that of the middle rotary drum (1) in the second mode;

the rotating speed of the pushing spiral in the first mode is smaller than that of the pushing spiral in the second mode.

10. The method of using a liquid-liquid horizontal screw machine according to claim 9, wherein the power system comprises: a main motor for controlling the rotating speed of the rotary drum (1) and a secondary motor for controlling the rotating speed of the pushing spiral;

the mode of regulating the power system is as follows: regulating and controlling the rotating speed of the main motor and regulating and controlling the differential rotating speed of the main motor and the auxiliary motor.