CN112604314B

CN112604314B - Vacuum evaporation unit for oil-containing solvent, oil-containing solvent recovery system and oil-containing solvent recovery method

Info

Publication number: CN112604314B
Application number: CN202011455506.3A
Authority: CN
Inventors: 阳光军; 高伟军; 唐学文; 周林辉; 李友廷
Original assignee: Hunan Changke Chengxiang Petrochemical Technology Co ltd
Current assignee: Hunan Changke Chengxiang Petrochemical Technology Co ltd
Priority date: 2020-12-10
Filing date: 2020-12-10
Publication date: 2022-12-23
Anticipated expiration: 2040-12-10
Also published as: CN112604314A

Abstract

The disclosure relates to an oily solvent vacuum evaporation unit, an oily solvent recovery system and an oily solvent recovery method. The oily solvent vacuum evaporation unit comprises a shell (1), a heat exchange element (2), and an oily solvent first inlet (3), a solvent steam first outlet (5), a solvent hot steam first inlet (6) and a liquid phase solvent first outlet (7) which are arranged on the shell (1). The oil-containing solvent recovery system comprises a vapor compression unit and the oil-containing solvent vacuum evaporation unit. The oily solvent recovery system provided by the disclosure reduces the energy consumption of solvent evaporation recovery.

Description

Vacuum evaporation unit for oil-containing solvent, oil-containing solvent recovery system and oil-containing solvent recovery method

Technical Field

The disclosure relates to the field of recovery of an oil-containing solvent, in particular to a vacuum evaporation unit of the oil-containing solvent, a recovery system of the oil-containing solvent and a recovery method of the oil-containing solvent.

Background

In the treatment process of the oily sludge, a solvent extraction process may be used to treat the oily sludge. After the oily sludge is extracted by the solvent, oil in the oily sludge is transferred into the extraction solvent, and the oil and the solvent are mixed together and are not easy to separate, so that the solvent is changed into an oily solvent mixture. The solvent is a high-value chemical and must be recycled.

In the existing extraction process of oil-containing sludge, the adopted solvent generally has larger difference with the property of oil in the sludge. Firstly, the difference between the volatile points of the solvent and the oil is large, the volatile point of the selected solvent is generally between 80 and 150 ℃, and the volatile point of the oil in the sludge is generally more than 150 ℃; secondly, the solvent has a narrow volatilization temperature range, generally within 20 ℃, while the oil has a wide volatilization temperature range, some of which are as high as 500 ℃. Thus, the solvent can be separated from the oil-containing solvent mixture by a thermal evaporation process, taking advantage of the difference in properties of the solvent and the oil.

The common solvent heating evaporation method is as follows: heating the oil-containing solvent mixture to a temperature above the volatilization point of the solvent by using steam or heat conduction oil, controlling the temperature below the volatilization point of the oil, so that the solvent is changed into a gas phase to be evaporated, and simultaneously, the oil is kept in a liquid phase state and is left at the bottom of an evaporation tank; then the evaporated solvent is condensed into liquid phase solvent by using circulating water. The prior art has the defects that: the evaporation of the solvent requires the absorption of a large amount of latent heat of evaporation, and the condensation of the solvent from the gas phase to the liquid phase requires the release of a large amount of latent heat, which results in a large energy consumption for heating and condensation. Furthermore, since the temperature during condensation is not high, it is difficult to recover latent heat released by solvent condensation. Thus resulting in high overall energy consumption for the solvent evaporation process.

Disclosure of Invention

The purpose of the present disclosure is to provide an oily solvent vacuum evaporation unit, an oily solvent recovery system and an oily solvent recovery method. The oil-containing solvent recovery system takes the oil-containing solvent vacuum evaporation unit as a core, thereby realizing the recovery and utilization of latent heat released by solvent condensation and reducing the energy consumption of solvent recovery.

In order to achieve the above object, a first aspect of the present disclosure provides an oily solvent vacuum evaporation unit, which includes a casing, a heat exchange element, and an oily solvent first inlet, a solvent vapor first outlet, a solvent hot vapor first inlet, and a liquid phase solvent first outlet, which are disposed on the casing;

the heat exchange element is arranged in the shell, is close to the upper wall of the shell and is arranged at intervals with the upper wall of the shell;

the heat exchange element comprises a heating channel, a condensing channel, a second inlet of the oil-containing solvent, a gas-liquid mixture outlet, a second inlet of solvent hot steam and a second outlet of the liquid-phase solvent;

wherein the heating channel and the condensing channel are arranged side by side so that substances in the heating channel and the condensing channel can perform partition wall heat exchange;

the bottom end of the heating channel is provided with the second oily solvent inlet which is communicated with the first oily solvent inlet of the shell through a sealing pipeline; the gas-liquid mixture outlet is arranged at the top end of the first heating channel, and the interior of the first heating channel is communicated with the interior of the shell only through the gas-liquid mixture outlet;

the top end of the condensation channel is provided with a second solvent hot steam inlet which is communicated with a first solvent hot steam outlet of the shell through a sealing pipeline; the second outlet of the liquid phase solvent is arranged at the bottom end of the condensation channel and is communicated with the first outlet of the liquid phase solvent of the shell through a sealed pipeline;

the first solvent vapor outlet is used for being communicated with an inlet of a vapor compression device; the first inlet of the solvent hot vapor is used for communicating with the outlet of the vapor compression device.

Optionally, the heat exchange element includes two heating channels, the two heating channels are respectively arranged on two sides of the condensing channel side by side, and the heat exchange element further includes a first heat exchange plate, a second heat exchange plate, a third heat exchange plate and a fourth heat exchange plate;

the first heat exchange plate, the second heat exchange plate, the third heat exchange plate and the fourth heat exchange plate are sequentially arranged in parallel at intervals;

a bottom plate is connected between the bottom ends of the first heat exchange plate and the second heat exchange plate so as to form a first heating channel between the two heat exchange plates, a bottom plate is connected between the bottom ends of the third heat exchange plate and the fourth heat exchange plate so as to form a second heating channel between the two heat exchange plates, and a second inlet of the oil-containing solvent is respectively arranged on the bottom plate of each heating channel;

the top ends and the bottom ends of the second heat exchange plate and the third heat exchange plate are respectively connected with a top plate and a bottom plate so as to form the condensation channel between the two heat exchange plates; the solvent hot steam second inlet is arranged on the top plate of the condensation channel; the second outlet of the liquid phase solvent is arranged on the bottom plate of the condensation channel;

optionally, the first heat exchange plate, the second heat exchange plate, the third heat exchange plate and the fourth heat exchange plate are respectively and independently selected from one or more of a stainless steel plate, a carbon steel plate, a titanium steel plate, a polytetrafluoroethylene plate, a copper plate, a graphite plate and a polyvinyl chloride plate;

optionally, the first heat exchange plate, the second heat exchange plate, the third heat exchange plate and the fourth heat exchange plate are each independently provided with a fluid passage on at least one side plate.

Optionally, the heat exchange element further comprises at least one secondary evaporation panel, and the secondary evaporation panel is arranged outside the heating channel and parallel to the side wall of the heating channel at an interval; optionally, the interval between the secondary evaporation panel and the heating channel is 0-5 cm;

optionally, the secondary evaporation panel is selected from one or more of a steel plate, a punched steel plate, a steel wire woven mesh, a steel wire pressed block, a polytetrafluoroethylene woven mesh and a polytetrafluoroethylene wire mesh pressed block.

Optionally, the oily solvent vacuum evaporation unit comprises a plurality of heat exchange elements in the shell; a plurality of heat exchange elements are arranged in the shell at intervals along the axial direction; the heating channel of each heat exchange element extends along the direction perpendicular to the axial direction of the shell and is spaced from the bottom of the shell.

Optionally, a start-up steam inlet is further arranged on the shell, and the start-up steam inlet is communicated with a second solvent hot steam inlet of the heat exchange element through a sealed pipeline;

optionally, a concentrated solution circulating outlet is further arranged on the shell, and the concentrated solution circulating outlet is communicated with the heating channel of the heating element; optionally, the concentrate recycling outlet is communicated with the first inlet of the oil-containing solvent of the shell;

the shell is provided with a concentrated solution outlet, and the concentrated solution outlet is communicated with an oil-containing concentrated solution collecting device.

Optionally, a liquid level meter is arranged in the shell, and the liquid level meter is close to the bottom of the shell and is spaced from the bottom;

optionally, a maintenance mounting opening is formed in the first side wall of the shell;

optionally, a pressure measuring device is disposed in the housing, and the pressure measuring device is close to a second side wall of the housing, and the second side wall is opposite to the first side wall;

optionally, the solvent hot vapor first inlet is disposed on the second sidewall.

A second aspect of the present disclosure provides an oil-laden solvent recovery system, the recovery system comprising a vapor compression unit and the oil-laden solvent vacuum evaporation unit provided by the first aspect of the present disclosure;

the vapor compression unit comprises a vapor compression device; the inlet of the vapor compression device is communicated with the first solvent vapor outlet of the vacuum evaporation unit, and the outlet of the vapor compression device is communicated with the first solvent hot vapor inlet of the vacuum evaporation unit.

Optionally, the vapour compression unit further comprises a second control means; the second control device is respectively in signal connection with the vapor compression device and the pressure measuring device of the oil-containing solvent vacuum evaporation unit so as to control the rotating speed of the vapor compression device according to the pressure signal detected by the pressure measuring device.

Optionally, the oil-containing solvent recovery system further comprises a concentrate output unit and a concentrate circulation unit;

the concentrated solution output unit comprises a concentrated solution output device and a first control device, wherein an inlet of the concentrated solution output device is communicated with a concentrated solution output port of the oily solvent vacuum evaporation unit, and an outlet of the concentrated solution output device is communicated with an oily concentrated solution collecting device; the first control device is respectively in signal connection with the concentrated solution output device and a liquid level meter in the oily solvent vacuum evaporation unit so as to control the rotating speed of the concentrated solution output device according to a liquid level signal detected by the liquid level meter;

the concentrate circulating unit comprises a concentrate circulating device, a flow measuring device and a third control device; an inlet of the concentrated solution circulating device is communicated with a concentrated solution circulating outlet of the oily solvent vacuum evaporation unit, and an outlet of the concentrated solution circulating device is communicated with a first oily solvent inlet of the oily solvent vacuum evaporation unit; the flow measuring device is arranged between the outlet of the concentrated solution circulating device and the first inlet of the oil-containing solvent; and the third control device is respectively connected with the flow measuring device and the concentrated solution circulating device in a signal mode so as to control the rotating speed of the concentrated solution circulating device according to the flow signals detected by the flow measuring device.

Optionally, the concentrate circulation unit further comprises a first valve and a second valve; the first valve is arranged between an inlet of the concentrated solution circulating device and a concentrated solution circulating outlet; the second valve is arranged between the outlet of the concentrated solution circulating device and the first inlet of the oil-containing solvent;

the concentrated solution output unit further comprises a third valve and a fourth valve; wherein the third valve is arranged between the inlet of the concentrated solution output device and the first concentrated solution outlet; the fourth valve is arranged between the outlet of the concentrated solution output device and the concentrated solution collecting device;

and, the oil-laden solvent recovery system has one of a concentrate circulation operation state, a concentrate discharge operation state, and a concentrate circulation-discharge operation state:

in a concentrated solution circulating working state, the first valve and the second valve are opened, the third valve and the fourth valve are closed, so that the inlet of the concentrated solution circulating device is communicated with the concentrated solution circulating outlet, and the outlet of the concentrated solution circulating device is communicated with the first inlet of the oil-containing solvent;

in the working state of concentrated solution discharge, the first valve and the second valve are closed, the third valve and the fourth valve are opened, so that the inlet of the concentrated solution output device is communicated with the first concentrated solution outlet, and the outlet of the concentrated solution output device is communicated with the concentrated solution collecting device;

in the working state of circulating and discharging the concentrated solution, the first valve, the second valve, the third valve and the fourth valve are opened, the inlet of the concentrated solution circulating device is communicated with the concentrated solution circulating outlet, the outlet of the concentrated solution circulating device is communicated with the first inlet of the oil-containing solvent, the inlet of the concentrated solution output device is communicated with the first outlet of the concentrated solution, and the outlet of the concentrated solution output device is communicated with the concentrated solution collecting device.

Optionally, the oil-containing solvent recovery system further comprises a start-up steam gas source, and the start-up steam gas source is communicated with the start-up steam inlet of the shell; a fifth valve is arranged between the start-up steam source and the start-up steam inlet;

the oil-containing solvent recovery system has a start-up steam working state and a solvent hot steam working state;

in the working state of the start-up steam, the fifth valve is opened, the start-up steam air source is communicated with the start-up steam inlet, the outlet of the steam compression device is communicated with the first solvent hot steam inlet, and the inlet of the steam compression device is communicated with the first solvent steam outlet;

in the solvent hot vapor state, the fifth valve is closed, only the outlet of the vapor compression device is communicated with the first solvent hot vapor inlet, and the inlet of the vapor compression device is communicated with the first solvent vapor outlet;

optionally, the opening and closing of the fifth valve is determined according to the rotation speed of the vapor compression device and the detection data of the pressure measurement device.

The third aspect of the present disclosure provides a method for recovering an oily solvent, using the system for recovering an oily solvent provided by the second aspect, the method comprising the steps of:

-the oily solvent to be recovered enters the heating channel of the heat exchange element through the first oily solvent inlet, the solvent hot steam enters the condensation channel of the heat exchange element through the first solvent hot steam inlet, and the solvent hot steam and the oily solvent to be recovered undergo partition wall heat exchange to obtain an oily concentrate, solvent steam and a liquid phase solvent;

-passing the solvent vapor into the vapor compression unit through a solvent vapor first outlet.

Through the technical scheme, the oily solvent vacuum evaporation unit that this disclosure provided, utilize the heat of solvent heat steam self to carry out the heat transfer to the oily solvent of treating the recovery, in the heating channel solvent is by heating evaporation, solvent heat steam self in the condensing channel is also by the condensation, this oily solvent vacuum evaporation unit can recycle the heat of solvent heat steam condensation release, greatly reduced the evaporation energy consumption of system, solvent heat steam does not need the plus circulating water cooling just can condense into liquid phase solvent simultaneously, the energy consumption of condensation has also been reduced.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure, but do not constitute a limitation of the disclosure. In the drawings:

FIG. 1 is a schematic structural diagram of an oily solvent vacuum evaporation unit provided by one embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a heat exchange element provided in one embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of an oil-containing solvent recovery system according to an embodiment of the present disclosure.

Description of the reference numerals

1-housing, 2-heat exchange element, 3-first inlet for solvent-laden vapor, 4-outlet for concentrate, 5-first outlet for solvent vapor, 6-first inlet for solvent-laden vapor, 7-first outlet for liquid-phase solvent, 8-first heat exchange plate, 9-second heat exchange plate, 10-third heat exchange plate, 11-fourth heat exchange plate, 12-second inlet for solvent-laden vapor, 14-outlet for gas-liquid mixture, 16-second inlet for solvent-laden vapor, 17-second outlet for liquid-phase solvent, 18-heating channel, 20-condensing channel, 21-secondary evaporation panel, 22-inlet for start-up vapor, 23-outlet for circulation of concentrate, 24-level gauge, 25-first side wall, 26-service mounting port, 27-second side wall, 29-vacuum evaporation unit for solvent-laden vapor, 31-outlet unit for concentrate, 32 vapor compression unit, 33-outlet unit for concentrate, 34-first control device, 35-source for concentrate collection device, 36-vapor compression device, 37-second control device, 38-pressure measurement device, 38-valve device, 39-pressure measurement device, 40-third valve, 43-flow measurement device, 43-third valve, 40-third valve, 46-third control device, 40-third valve, 40-flow measurement device, 40-fourth valve, 40-third control device, 40-fourth valve, and fourth valve

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

In the present disclosure, unless otherwise specified, the terms "first", "second", "third", and the like are used only for distinguishing different members and do not have actual meanings such as the order of connection before and after the present disclosure. In the present disclosure, the use of directional words such as "upper, lower, top and bottom" generally refers to upper and lower, top and bottom, respectively, of the device in its normal use condition. "inner and outer" are with respect to the device profile. For example, the phrase "the secondary evaporation panel is disposed outside the heating passage" means that the heating element is used as the whole device, and the secondary evaporation panel is disposed outside the heating passage of the device.

As shown in fig. 1, a first aspect of the present disclosure provides an oil-containing solvent vacuum evaporation unit, where the oil-containing solvent vacuum evaporation unit 29 includes a housing 1, a heat exchange element 2, and a first inlet 3 for oil-containing solvent, a first outlet 5 for solvent vapor, a first inlet 6 for solvent hot vapor, and a first outlet 7 for liquid phase solvent, which are disposed on the housing;

the heat exchange element 2 is arranged in the shell 1, is close to the upper wall of the shell 1 and is arranged at intervals with the upper wall of the shell 1;

the heating channel and the condensing channel are arranged side by side, so that substances in the heating channel and the condensing channel can perform partition wall heat exchange;

the bottom end of the heating channel is provided with a second oily solvent inlet which is communicated with the first oily solvent inlet 3 of the shell through a sealing pipeline; the gas-liquid mixture outlet is arranged at the top end of the first heating channel, and the interior of the first heating channel is communicated with the interior of the shell 1 only through the gas-liquid mixture outlet;

the top end of the condensing channel is provided with a second solvent hot steam inlet which is communicated with the first solvent hot steam inlet 6 of the shell through a sealing pipeline; the second outlet of the liquid phase solvent is arranged at the bottom end of the condensing channel and is communicated with the first outlet 7 of the liquid phase solvent of the shell through a sealed pipeline;

a first outlet 5 for solvent vapour for communication with the inlet of the vapour compression device; the first inlet 6 for solvent hot vapour is adapted to communicate with the outlet of the vapour compression device.

The utility model provides an oily solvent vacuum evaporation unit, utilize the heat of solvent heat steam self to treat the oily solvent of recovery and carry out the heat transfer, in the heating channel while solvent is heated evaporation, solvent heat steam self in the condensing channel is also by the condensation, this oily solvent vacuum evaporation unit can recycle the heat of solvent heat steam condensation release, greatly reduced the evaporation energy consumption of system, solvent heat steam does not need the cooling of extra circulating water just can condense into liquid phase solvent simultaneously, the energy consumption of condensation has also been reduced.

The term "solvent heat vapor" as used herein refers to solvent heat vapor obtained by the oily solvent vacuum evaporation unit after being drawn out from the evaporation unit, the temperature of the solvent vapor being raised, and then being reintroduced into the oily solvent vacuum evaporation unit for the purpose of partition wall heat exchange.

The working principle of the heat exchange element in the oily solvent vacuum evaporation unit provided by the disclosure is as follows:

in the heating channel, the oil-containing solvent enters the heating channel from a second oil-containing solvent inlet at the bottom end of the heating channel and moves upwards, and meanwhile, the oil-containing solvent and solvent hot steam in the condensing channel perform partition wall heat exchange, so that the temperature of the oil-containing solvent is higher and higher; when the temperature reaches the evaporation temperature of the solvent, the solvent in the oil-containing solvent is evaporated, the steam also moves upwards and enters the shell from the gas-liquid mixture outlet, meanwhile, the oil-containing solvent is continuously concentrated, the oil content is higher and higher, and oil-containing concentrated solution is obtained; when the oil-containing concentrated solution moves to the gas-liquid mixture outlet at the top end of the heating channel, the oil-containing concentrated solution overflows from the gas-liquid mixture outlet and enters the shell, and the oil-containing concentrated solution is subjected to flash evaporation, so that the residual unevaporated solvent in the oil-containing concentrated solution is further volatilized into a gas phase, and the evaporation capacity of solvent steam is improved; the oil-containing concentrate then flows to the bottom of the housing.

In the condensation channel, the solvent hot steam enters the condensation channel through the second solvent hot steam inlet at the top end of the condensation channel and exchanges wall heat with the oil-containing solvent in the heating channel, and the solvent hot steam is condensed into the liquid-phase solvent while transferring heat to the oil-containing solvent, flows downwards in the condensation channel and flows out of the heat exchange element from the second liquid-phase solvent outlet. The inlet and the outlet of the condensation channel are communicated with the outside of the vacuum evaporation unit through a sealed pipeline, the air pressure in the condensation channel can keep positive pressure, the condensation of the solvent is facilitated, and the yield of the liquid phase solvent is improved.

In one embodiment, referring to fig. 2, the heat exchange element 2 of the oil-containing solvent vacuum evaporation unit 29 comprises two heating channels 18, the two heating channels 18 are respectively arranged on two sides of the condensing channel 20 side by side, and the condensing channel can be used for simultaneously performing partition wall heat exchange on the two heating channels, so that the heat exchange efficiency is improved. In the present embodiment, the heat exchange element 2 further comprises a first heat exchange plate 8, a second heat exchange plate 9, a third heat exchange plate 10 and a fourth heat exchange plate 11; the first heat exchange plate 8, the second heat exchange plate 9, the third heat exchange plate 10 and the fourth heat exchange plate 11 are sequentially arranged in parallel at intervals;

a bottom plate is connected between the bottom ends of the first heat exchange plate 8 and the second heat exchange plate 9 to form a first heating channel 18 between the two heat exchange plates, and a bottom plate is connected between the bottom ends of the third heat exchange plate 10 and the fourth heat exchange plate 11 to form a second heating channel 18 between the two heat exchange plates; the second inlets 12 of the oil-containing solvent are respectively arranged on the bottom plate of each heating channel;

the top ends and the bottom ends of the second heat exchange plate 9 and the third heat exchange plate 10 are respectively connected with a top plate and a bottom plate to form a condensation channel 20 between the two heat exchange plates; the solvent hot vapor second inlet 16 is disposed on the ceiling of the condensing passage 20; the second outlet 17 for the liquid-phase solvent is provided on the bottom plate of the condensing passage 20.

In this embodiment, the bottom plates of the two heating channels are provided with the second inlets of the oil-containing solvent, the housing may be provided with a common first inlet of the oil-containing solvent, the first inlet of the oil-containing solvent introduces a plurality of branch sealing pipelines into the housing, the branch sealing pipelines are respectively communicated with the second inlets of the oil-containing solvent of each heating channel, and the oil-containing solvent is introduced into each heating channel. The shell is only provided with the first inlet of the oil-containing solvent, and the branch sealing pipeline is led out from the interior of the shell, so that the risk of leakage of substances in the whole evaporation unit can be reduced, and the safety of the device is improved.

In a specific embodiment, the first heat exchange plate, the second heat exchange plate, the third heat exchange plate and the fourth heat exchange plate are respectively and independently selected from one or more of a stainless steel plate, a carbon steel plate, a titanium steel plate, a polytetrafluoroethylene plate, a copper plate, a graphite plate and a polyvinyl chloride plate.

In a preferred embodiment, at least one side of the first heat exchange plate 8, the second heat exchange plate 9, the third heat exchange plate 10 and the fourth heat exchange plate 11 is provided with a fluid channel independently. The fluid channel refers to a channel for guiding the circulation of liquid on the heat exchange plate in the heating channel or the condensing channel. The oil solvent in the heating channel of the heat exchange element flows from bottom to top, the liquid phase solvent obtained after the solvent steam in the condensing channel is condensed flows from the heat exchange plates to bottom, and the heating plate is provided with the fluid channel, for example, a corrugated fluid channel can be arranged on each heat exchange plate, so that the liquid in the heating channel or the condensing channel can uniformly flow through all areas of the heat exchange plates, and dead angles are avoided.

In one embodiment, the single heat exchange plate may be a rectangular thin plate, and the heat exchange plate may be one or more selected from a stainless steel plate, a carbon steel plate, a titanium steel plate, a teflon plate, a copper plate, a graphite plate, and a polyvinyl chloride plate.

In one embodiment, referring to fig. 2, the heat exchange element 2 further comprises at least one secondary evaporation panel 21, the secondary evaporation panel 21 is disposed outside the heating channel 18 and is parallel to and spaced apart from the side wall of the heating channel 18; optionally, the interval between the secondary evaporation panel 21 and the heating channel 18 is 0 to 5cm.

This embodiment sets up the secondary evaporation panel in the outside of heating channel for on the oily concentrate that overflows from gas-liquid mixture outlet 14 was guided the secondary evaporation panel, the liquid stream becomes liquid film, greatly increased the evaporation area of liquid phase, make the solvent that is carried by oily concentrate produce the secondary evaporation, further improve solvent steam content, improve solvent recovery rate.

In a preferred embodiment, as shown in fig. 2, the heat exchange element comprises two heating channels 18, and a secondary evaporation panel 21 is provided on the outer side of each heating channel 18. Specifically, a secondary evaporation panel is arranged on the outer side of a first heat exchange plate of the first heating channel at intervals in parallel, and a secondary evaporation panel is arranged on the outer side of a fourth heat exchange plate of the second heating channel at intervals in parallel, so that the solvent evaporation recovery is further improved.

In one embodiment, the height of the top edge of the secondary evaporation panel 21 is lower than the height of the top end of the heating channel 18, so that the oil-containing concentrated solution has enough space to overflow to the secondary evaporation panel; optionally, the bottom edge of the secondary evaporation panel 21 extends downward to enable the secondary evaporation panel 21 to guide the oil-containing concentrate to the bottom of the housing and provide a larger surface area for further evaporation of the solvent in the concentrate.

In one embodiment, the secondary evaporation panel 21 is selected from one or more of steel plate, punched steel plate, woven wire mesh, pressed steel wire block, woven polytetrafluoroethylene mesh, and pressed polytetrafluoroethylene mesh block. The secondary evaporation panel is made of corrosion-resistant material with a larger specific surface, so that the durability of the secondary evaporation panel is improved.

In a preferred embodiment, referring to fig. 1, a plurality of heat exchange elements 2 are included in a housing 1 of an oil-containing solvent vacuum evaporation unit 29; alternatively, a plurality of heat exchange elements 2 are arranged at intervals in the axial direction of the shell in the shell 1; wherein, a plurality of heat exchange elements are arranged at intervals along the axial direction of the shell 1; and the heating passage 18 of each heat exchange member 2 extends in a direction perpendicular to the axial direction of the housing 1 with a space from the bottom of the housing 1. In the oily solvent vacuum evaporation unit, the number of the heat exchange units can be determined according to the total amount of the oily solvent to be recovered and treated. The evaporation and concentration efficiency of the vacuum evaporation unit can be improved by adopting the combined application of a plurality of heat exchange elements.

In the preferred embodiment, the second inlet of the oily solvent at the bottom end of the heating channel of each heat exchange element is communicated with the first inlet of the oily solvent on the shell of the oily solvent vacuum evaporation unit by adopting a sealed pipeline, and the top end of each heating channel is communicated with the inside of the shell through a gas-liquid mixture outlet; and a second solvent hot steam inlet at the top end of the condensation channel of each heat exchange element is communicated with a first solvent hot steam inlet on the shell of the oily solvent vacuum evaporation unit by adopting a sealed pipeline, and a second liquid phase solvent outlet at the bottom end of each condensation channel is also communicated with a first liquid phase solvent outlet on the shell of the oily solvent vacuum evaporation unit by adopting a sealed pipeline.

In the above preferred embodiment, there is a space between every two heat exchange elements 2, and a secondary evaporation panel 21 may be disposed in the space near the heating channel 18 to promote secondary evaporation of the solvent carried by the oil-containing concentrate.

In another preferred embodiment, a plurality of heat exchange elements 2 can be arranged side by side without a gap in the housing 1 of the vacuum evaporation unit. In the preferred embodiment, the heating channel of one heat exchange element can be directly arranged side by side with the condensing channel of another heat exchange element without a space, and in this arrangement, a plurality of heat exchange elements arranged side by side without space can be used as a larger heat exchange element, wherein the heating channel and the condensing channel are alternately arranged. The arrangement mode of the heat exchange elements provided by the preferred embodiment enables the heat exchange elements to have higher heat exchange efficiency and save space.

In the above preferred embodiment, the arrangement of the heat exchange elements is a condensing channel, a heating channel, another condensing channel, and another heating channel, which are sequentially arranged. Then N condensation channels can be matched with N heating channels, and 2N +1 heat exchange plates are used; optionally, the 2n +1 heat exchange plates are mounted on a frame side by side and can be fixed by bolts, and the bolts also provide sealing pressing force between the heat exchange plates. The heat exchange plates 2N +1 which are arranged side by side form an integral heat exchange element.

In both preferred embodiments of the heat exchange element described above, there are a plurality of heating channels and a plurality of condensing channels. The oil-containing solvent recovery device comprises a plurality of heating channels, a plurality of oil-containing solvent recovery inlets and a plurality of oil-containing solvent recovery inlets, wherein the plurality of heating channels adopt a plurality of branch sealing pipelines for uniformly distributing the oil-containing solvent to be recovered, which is introduced from the oil-containing solvent first inlet, to each heating channel; for the first inlet of the solvent hot steam, a plurality of branch sealing pipelines can also be led out to uniformly distribute the solvent hot steam into each condensation channel, and the liquid phase solvent flowing out from the second outlets of the liquid phase solvents of all condensation channels is gathered to the first outlet of the liquid phase solvent by adopting the plurality of branch sealing pipelines.

In a specific embodiment, the shell of the oil-containing solvent vacuum evaporation unit provided by the present disclosure is a sealed horizontal container, for example, a horizontal pressure container resistant to negative pressure of-98 KPa, and the use of the container resistant to negative pressure as the shell is beneficial to the negative pressure state inside the evaporation unit after solvent vapor is extracted during the application process, so as to improve the service life of the evaporation unit. Specifically, the heat exchange element in the embodiment is arranged at the upper part of the horizontal container, and has a gap with the top end of the container; the lower part of the horizontal container is a storage space for the oil-containing concentrated solution obtained after the solvent is evaporated.

In one embodiment, in the vacuum evaporation unit, the first side wall of the casing is further provided with an inspection mounting opening 26, so that the vacuum evaporation unit can be inspected conveniently.

In one embodiment, the first inlet 3 of the oil-containing solvent and the first outlet 5 of the solvent vapor of the vacuum evaporation unit 29 are both disposed on the upper wall of the housing with a space therebetween, wherein the first inlet of the oil-containing solvent is close to the first sidewall of the housing, and the first outlet 5 of the solvent vapor is close to the second sidewall of the housing; the first outlet 7 for the liquid phase solvent may be provided in the lower wall of the housing. Alternatively, the first inlet 6 for solvent hot vapor may be provided on a second sidewall of the housing, wherein the second sidewall is provided corresponding to the first sidewall. By adopting the position of each inlet or outlet on the shell in the embodiment, the overall working efficiency of the oily solvent vacuum evaporation unit can be improved on the basis of fully utilizing the properties of different materials.

In one embodiment, a pressure measuring device 38 is disposed within the housing 1, and the pressure measuring device 38 is disposed adjacent to the second side wall of the housing for detecting the internal pressure of the housing.

In one embodiment, the housing of the vacuum evaporation unit is further provided with a concentrate circulation outlet 23, and the concentrate circulation outlet 23 is communicated with the heating channel of the heating element; optionally, the concentrate recycling outlet 23 is in communication with the first inlet 3 for the oil-laden solvent. Optionally, the concentrate recycling outlet is provided at the bottom of the housing. The oil-containing concentrated solution obtained from the heating channel of the heating element falls into the bottom of the shell, but part of solvent which is not evaporated can still be carried in the oil-containing concentrated solution, the concentrated solution circulating outlet is arranged on the shell, the concentrated solution at the bottom of the shell can be pumped out and then returns to the first inlet of the oil-containing solvent on the shell, and the oil-containing concentrated solution and the original oil-containing solvent to be recovered enter the heating channel of the heat exchange element together, so that the evaporation concentration is further performed, the solvent content in the oil-containing concentrated solution is reduced, and the solvent recovery rate is improved.

In one embodiment, the housing of the oily solvent vacuum evaporation unit is further provided with a concentrated solution output port 4, and the concentrated solution output port 4 is used for communicating with an oily concentrated solution collecting device.

In one embodiment, a liquid level meter 24 is further disposed inside the casing 1 of the oily solvent vacuum evaporation unit 29, and the liquid level meter 24 is close to and spaced from the bottom of the casing 1 for detecting the level of the oily concentrate stored in the lower part of the casing.

In one embodiment, the casing of the oil-containing solvent vacuum evaporation unit 29 is further provided with a start-up steam inlet 22, and the start-up steam inlet 22 is communicated with the solvent hot steam second inlet 16 of the heat exchange element 2 through a sealed pipeline. The start-up steam represents water vapor introduced from the outside in order to supply heat required for solvent evaporation to the heat exchange element, while solvent vapor is not generated inside the housing yet in the start-up phase of the vacuum heat exchange unit. In this embodiment, the start-up steam introduced from the start-up steam inlet enters the condensation channel of the heat exchange element, and the start-up steam is used as a heat source to heat the oil-containing solvent to be recovered in the heating channel, so that the solvent is evaporated to obtain the solvent steam.

Referring to fig. 3, a second aspect of the present disclosure provides an oily solvent recovery system, the recovery system comprising a vapor compression unit and an oily solvent vacuum evaporation unit provided by the first aspect of the present disclosure;

wherein the vapor compression unit 32 includes a vapor compression device 36; the outlet of the vapor compression device is communicated with the first inlet 6 of the solvent hot vapor of the oil-containing solvent vacuum evaporation unit 29, and the inlet of the vapor compression device is communicated with the first outlet 5 of the solvent vapor of the oil-containing solvent vacuum evaporation unit 29.

The oily solvent recovery system further compresses the solvent steam obtained by the oily solvent vacuum evaporation unit, improves the temperature of the solvent steam to obtain the solvent hot steam, introduces the solvent hot steam into the evaporation unit to be used as a heating source to exchange heat with the oily solvent to be recovered, condenses the solvent hot steam, recovers the latent heat of evaporation of the solvent hot steam, greatly reduces the evaporation energy consumption, does not need circulating water for cooling the solvent hot steam, and reduces the energy consumption of cooling.

Specifically, the process flow of the vapor compression unit and the oily solvent vacuum evaporation unit combined is as follows: extracting the solvent vapor evaporated from the vacuum evaporation unit through a first solvent vapor outlet by using a vapor compression device, compressing the extracted solvent vapor by using the vapor compression device, and increasing the temperature and pressure of the vapor to increase the enthalpy value so that the temperature and enthalpy value of the compressed vapor are higher than the temperature of the oil-containing solvent mixture in the heating channel of the heat exchange element to obtain solvent hot vapor; the vapor compression device continuously extracts gas-phase substances in the oil-containing solvent vacuum evaporation unit in the operation process, so that the interior of the vacuum evaporation unit is in a negative pressure state, and the solvent evaporation effect is further enhanced; and then, the compressed solvent hot steam is introduced into a condensation channel of the heat exchange element through a first solvent hot steam inlet by using a steam compression device, the heat of the high-temperature solvent hot steam is conducted to the low-temperature oil-containing solvent to be recovered, the temperature of the oil-containing solvent rises, the solvent is evaporated, the temperature of the solvent hot steam in the condensation channel drops, and the solvent is condensed into a liquid-phase solvent.

In one embodiment, the vapour compression unit 32 further comprises second control means 37; the second control device is respectively in signal connection with the vapor compression device and the pressure measuring device 38 of the vacuum evaporation unit 29, so as to control the rotating speed of the vapor compression device according to the pressure signal detected by the pressure measuring device, thus the pressure in the vacuum evaporation unit can be kept stable, and the energy consumption of the vapor compression device is prevented from being too high; alternatively, the pressure measuring device may be a pressure gauge, which may be mounted on the second secondary sidewall of the vacuum evaporation unit.

In particular, the vapour compression device may be a vapour compressor. Alternatively, the vapor compressor may be selected from a screw compressor, a centrifugal compressor, a reciprocating compressor, a roots compressor, and preferably a centrifugal compressor. The centrifugal compressor can keep the flow of the oil-containing solvent recovery system stable, high in efficiency and large in flow.

Alternatively, the controlling of the rotation speed of the vapor compression device may be controlling an inverter of the vapor compressor, and adjusting the output frequency of the inverter, thereby adjusting the rotation speed of the motor of the vapor compressor.

In one embodiment, the oil-laden solvent recovery system further includes a concentrate output unit 31 and a concentrate circulation unit 39.

In the present embodiment, the concentrate output unit 31 includes a concentrate output device 33 and a first control device 34, an inlet of the concentrate output device is communicated with the concentrate output port 4 of the vacuum evaporation unit 29, and an outlet of the concentrate output device is communicated with the oil-containing concentrate collection device 35; and the first control system device is respectively connected with the concentrated solution output device and the liquid level meter 24 of the vacuum evaporation unit 29 by signals so as to control the rotating speed of the concentrated solution output device according to the liquid level signals detected by the liquid level meter 24.

Specifically, the process flow of the concentrated solution output unit adopted in the embodiment is as follows: the oil-containing concentrated solution is stored at the bottom of the vacuum evaporation unit, is extracted through a concentrated solution output port by a concentrated solution output device and can be collected by an oil-containing concentrated solution collecting device; in the process, a liquid level meter in the vacuum evaporation unit detects the liquid level of the oily concentrated solution at the bottom of the shell, a liquid level signal is converted into a control signal in the first control device, the control signal is input into a frequency converter of the concentrated solution output device, the frequency of the frequency converter is adjusted according to the control signal, the frequency signal of the frequency converter adjusts the rotating speed of a motor of the concentrated solution output device, and the rotating speed of the motor controls the outlet flow of the concentrated solution output device, so that the liquid level at the bottom of the evaporator is controlled, the liquid level of the oily solvent in the vacuum evaporation unit can be maintained stable, the stability of the whole solvent recovery system is further maintained, and the reduction of the recovery efficiency caused by the large fluctuation of the system is avoided.

Alternatively, the concentrate output device may be a concentrate discharge pump. The concentrate discharge pump may be one of a centrifugal pump, a progressive cavity pump, a vane pump, and a reciprocating pump, and preferably a progressive cavity pump.

In the present embodiment, the concentrate circulation unit includes a concentrate circulation device 40, a flow rate measurement device 41, and a third control device 42, an inlet of the concentrate circulation device communicates with the concentrate circulation outlet 23 of the oil-containing solvent vacuum evaporation unit 29, an outlet of the concentrate circulation device communicates with the oil-containing solvent first inlet 3 of the oil-containing solvent vacuum evaporation unit 29, and the flow rate measurement device 41 is provided between the outlet of the concentrate circulation device and the oil-containing solvent first inlet 3; and a third control device is in signal connection with the flow measuring device and the concentrate circulating device, respectively, for controlling the rotational speed of the concentrate circulating device by means of the flow signal detected by the flow measuring device.

Specifically, the process flow of the concentrated solution circulation unit adopted in the embodiment is as follows:

the oil-containing solvent at the bottom of the vacuum evaporation unit is pumped out through a concentrated solution circulating outlet by utilizing a concentrated solution circulating device, then the pumped oil-containing concentrated solution is returned to a first inlet of the oil-containing solvent by utilizing the concentrated solution circulating device, and the oil-containing concentrated solution and the originally input oil-containing solvent are input into a heat exchange element for evaporation and concentration, so that the concentration of the oil-containing concentrated solution is further improved; and in the process, the flow measuring device measures the outlet flow of the concentrated solution circulating device, the flow signal is converted into a control signal in the third control device, the control signal is input into a frequency converter of the concentrated solution circulating device, the frequency of the frequency converter is adjusted according to the control signal, the frequency signal of the frequency converter is used for adjusting the rotating speed of a motor of the concentrated solution circulating device, and the rotating speed of the motor controls the outlet flow, so that the circulating flow of the concentrated solution is controlled.

Alternatively, the concentrate circulation pump may be one of a centrifugal pump, a progressive cavity pump, a vane pump, a reciprocating pump, preferably a progressive cavity pump.

In one embodiment, the first control device, the second control device, and the third control device may be a variable frequency motor controller.

In one embodiment, the concentrate circulation unit further comprises a first valve 43 disposed between the inlet of the concentrate circulation means and the concentrate circulation outlet 23 of the vacuum evaporation unit 29, and a second valve 44 disposed between the outlet of the concentrate circulation means and the first inlet 3 of the oily solvent vacuum evaporation unit 29;

the concentrated solution output unit 31 further comprises a third valve 45 and a fourth valve 46, the third valve is arranged between the inlet of the concentrated solution output device and the first concentrated solution outlet 4 of the vacuum evaporation unit 29, and the fourth valve is arranged between the outlet of the concentrated solution output device and the concentrated solution collecting device;

the oily solvent recovery system has one of a concentrate circulation operating state, a concentrate discharge operating state or a concentrate circulation-discharge operating state:

in the circulating working state of the concentrated solution, the first valve and the second valve are opened, the third valve and the fourth valve are closed, so that the inlet of the concentrated solution circulating device is communicated with the concentrated solution circulating outlet 23, and the outlet of the concentrated solution circulating device is communicated with the first oily solvent inlet 3 of the oily solvent vacuum evaporation unit 29;

in the working state of concentrated solution discharge, the first valve and the second valve are closed, the third valve and the fourth valve are opened, so that the inlet of the concentrated solution output device is communicated with the first concentrated solution outlet 4 of the vacuum evaporation unit 29, and the outlet of the concentrated solution output device is communicated with the concentrated solution collecting device;

in the concentrate circulation-discharge operation state, the first and second valves 43 and 44, the third and

fourth valves

45 and 46 are opened to communicate the inlet of the concentrate circulation device 40 with the concentrate circulation outlet 23, the outlet of the concentrate circulation device 40 with the oily solvent first inlet 3, and the inlet of the concentrate discharge device 33 with the concentrate first outlet 4, and the outlet of the concentrate discharge device 33 with the concentrate collection device 35.

In a specific embodiment, an off-line detection device for the oil-containing concentrated solution may be separately disposed outside the oil-containing solvent recovery system, and is configured to detect the content of the solvent in the oil-containing concentrated solution obtained by the vacuum evaporation unit of the oil-containing solvent, and determine the operating state of the oil-containing solvent recovery system according to the detection result.

In this embodiment, the solvent content in the oil-containing concentrated solution at the bottom of the vacuum evaporation unit is continuously reduced through the circulating working state of the concentrated solution, after the oil-containing concentrated solution detected by the concentrated solution analysis device reaches the discharge standard, the circulating unit of the concentrated solution can be closed, the discharge unit of the concentrated solution is opened, the system is in the working state of discharging the concentrated solution, and the oil-containing concentrated solution enters the concentrated solution collection device.

In one embodiment, the oil-laden solvent recovery system further comprises a start-up vapor gas source 47, the start-up vapor gas source 47 being in communication with the start-up vapor inlet 22 of the housing; a fifth valve 48 is arranged between the start-up steam source and the start-up steam inlet 22.

In the present embodiment, the oil-containing solvent recovery system has an operation state of steam and an operation state of compressed steam;

in the working state of the start-up steam, the fifth valve 48 is opened, the start-up steam source 47 is communicated with the start-up steam inlet 22, the outlet of the steam compression device is communicated with the first solvent hot steam inlet and outlet 6 of the vacuum evaporation unit 29, and the inlet of the steam compression device is communicated with the first solvent steam outlet 5;

in the compressed vapor operating state, the fifth valve 48 is closed, and only the outlet of the vapor compression device is communicated with the first inlet 6 of the solvent hot vapor of the vacuum evaporation unit 29, and the inlet of the vapor compression device is communicated with the first outlet 5 of the solvent vapor;

alternatively, the opening and closing of the fifth valve 48 is determined based on the rotational speed of the vapor compression device 36 and the detection data of the pressure measuring device 38.

In this embodiment, in the start-up stage of the system, the system is in a start-up steam operating state, water vapor is introduced from the outside as a heat source to heat the oil-containing solvent mixture, so that the solvent in the oil-containing solvent mixture is evaporated to form solvent vapor, and then the vapor compression device is slowly started to compress the solvent vapor to obtain solvent hot vapor, and the solvent hot vapor is sent to the heat exchange element condensation channel. And gradually reducing the flow of the start-up water vapor along with the increase of the flow of the outlet of the vapor compression device, and closing the fifth valve when the flow of the solvent hot vapor at the outlet of the vapor compression device reaches the normal flow, so that the system enters a compression working state.

The third aspect of the present disclosure provides an oily solvent recovery method, which employs the oily solvent recovery system provided by the second aspect of the present disclosure and the oily solvent vacuum evaporation unit provided by the first aspect, and which includes the steps of:

-the oily solvent to be recovered enters the heating channel of the heat exchange element 2 through the oily solvent first inlet 3, the solvent hot steam enters the condensation channel of the heat exchange element 2 through the solvent hot steam first inlet 6, and the solvent hot steam and the oily solvent to be recovered undergo partition wall heat exchange to obtain an oily concentrated solution, solvent steam and a liquid phase solvent;

-the solvent vapour is compressed in a vapour compression unit 32 via a first solvent vapour outlet 5 to obtain hot solvent vapour.

In one embodiment, the pressure in the oily solvent vacuum evaporation unit 29 is controlled at-98 KPa to-0.1 KPa, preferably-40 KPa to-10 KPa.

In one embodiment, the oily solvent recovery method is implemented by using the oily solvent vacuum evaporation unit shown in fig. 1, the heat exchange element shown in fig. 2 and the oily solvent recovery system shown in fig. 3, and comprises the following steps:

the oily solvent to be recovered is introduced into the oily solvent first inlet 3 on the shell 1 of the oily solvent vacuum evaporation unit 29 through a sealed pipeline, and then the oily solvent enters the oily solvent second inlet 12 on the bottom end of the heating channel 18 of the heat exchange element 2 and enters the heating channel 18; the heat exchange element 2 is shown in fig. 2 and comprises two heating channels 18; for example, as shown in fig. 1, the oily solvent vacuum evaporation unit 29 comprises 13 heat exchange elements 2, namely, 26 heating channels, and in the process, the oily solvent is uniformly introduced into each heating channel;

opening a fifth valve 48, introducing a start-up steam source 47 into the start-up steam inlet 22 on the shell, and then making the start-up steam enter the start-up steam inlet 22 at the top end of the condensation channel 20 of each heat exchange element 2 of the oil-containing solvent vacuum evaporation unit 29 and enter the condensation channels (13 condensation channels are known according to the foregoing steps), in each heat exchange element, the substance in the condensation channel transfers heat to the substance in the heating channel for heat exchange, the steam in the condensation channel is condensed into liquid and flows out from the liquid-phase solvent second outlet at the lower end, and the liquid flowing out from all the condensation channels 20 in the shell flows out from the liquid-phase solvent first outlet 7 on the shell through a sealed pipeline for collection; after the oil-containing solvent in the heating channel is heated to the solvent evaporation temperature, the solvent is evaporated, the oil-containing solvent is concentrated, the solvent steam and the oil-containing concentrated solution flow out from a gas-liquid mixture outlet 14 at the top end of the heating channel, a secondary evaporation panel 21 is arranged on the outer side of each heating channel, the oil-containing concentrated solution is guided to the secondary evaporation panels for secondary evaporation, and then the oil-containing concentrated solution falls into the bottom of the shell;

the vapor compression device 36 in the vacuum evaporation unit 29 is turned on, the vapor compression device extracts the evaporated solvent vapor from the first solvent vapor outlet 5 of the casing 1, compresses and heats the solvent vapor to obtain solvent hot vapor, then inputs the solvent hot vapor to the first solvent hot vapor inlet 6 on the casing 1, and then inputs the solvent hot vapor to the heat exchange element condensation channel, when the flow detection device 41 of the compressed vapor at the outlet of the vapor compression device 36 detects that the flow signal reaches the normal working flow, the fifth valve 48 is closed, only the compressed solvent hot vapor is introduced into the condensation channel, and during the operation of the vapor compression device, the rotation speed of the vapor compression device is controlled by the second control device 37 according to the pressure signal detected by the pressure measurement device 38 in the casing, in the present embodiment, the pressure in the casing is controlled to be maintained at about-25 KPa;

opening the first valve 43 and the second valve 44, opening, closing the third valve 45 and the fourth valve 46, connecting the inlet of the concentrated solution circulating device 40 with the concentrated solution circulating outlet 23, connecting the outlet of the concentrated solution circulating device 40 with the first inlet 3 of the oily solvent vacuum evaporation unit 29, extracting the oily concentrated solution stored at the lower part of the shell from the concentrated solution circulating outlet 23 on the shell by the concentrated solution circulating device 40, inputting the oily concentrated solution again to the first inlet 3 of the oily solvent on the shell 1, and entering the heat exchange element heating channel together with other oily solvent to be recovered to heat and evaporate the solvent, so that the oily concentrated solution is further concentrated;

after the oil-containing concentrated solution off-line detection device detects that the concentration of the oil-containing concentrated solution in the vacuum evaporation unit reaches the recovery standard, the first valve 43 and the second valve 44 are closed, the third valve 45 and the fourth valve 46 are opened, the inlet of the concentrated solution output device 33 is communicated with the concentrated solution first outlet 4 of the vacuum evaporation unit 29, the outlet of the concentrated solution output device 33 is communicated with the concentrated solution collection device 35, and the oil-containing concentrated solution in the casing is extracted through the concentrated solution output device and is conveyed to the concentrated solution collection device. When the concentrated solution circulating device or the concentrated solution output device works, the output rotating speed is adjusted by the corresponding first control device or the third control device according to the liquid level signal of the oil-containing concentrated solution detected by the liquid level meter in the shell.

The specific components and working principles of the oily solvent vacuum evaporation unit and the oily solvent recovery system adopted in the oily solvent recovery method provided by the present disclosure have been described in detail in the foregoing content, and thus are not described again.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that the various features described in the foregoing embodiments may be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure as long as it does not depart from the gist of the present disclosure.

Claims

1. The vacuum evaporation unit for the oil-containing solvent is characterized in that the vacuum evaporation unit (29) for the oil-containing solvent comprises a shell (1), a heat exchange element (2), and a first inlet (3) for the oil-containing solvent, a first outlet (5) for solvent steam, a first inlet (6) for solvent hot steam and a first outlet (7) for liquid phase solvent, which are arranged on the shell (1);

the heat exchange element (2) is arranged in the shell (1), is close to the upper wall of the shell (1) and is arranged at a distance from the upper wall of the shell (1);

the heat exchange element (2) comprises a heating channel, a condensing channel, a second inlet of the oil-containing solvent, a gas-liquid mixture outlet, a second inlet of solvent hot steam and a second outlet of the liquid-phase solvent;

the bottom end of the heating channel is provided with the second inlet of the oil-containing solvent, and the second inlet of the oil-containing solvent is communicated with the first inlet of the oil-containing solvent of the shell through a sealed pipeline; the gas-liquid mixture outlet is formed in the top end of the heating channel, and the interior of the heating channel is communicated with the interior of the shell (1) only through the gas-liquid mixture outlet;

the top end of the condensation channel is provided with a second solvent hot steam inlet which is communicated with the first solvent hot steam inlet (6) of the shell (1) through a sealed pipeline; the second outlet of the liquid phase solvent is arranged at the bottom end of the condensation channel and is communicated with the first outlet (7) of the liquid phase solvent of the shell through a sealed pipeline;

the first solvent vapor outlet (5) is used for communicating with an inlet of a vapor compression device; the first solvent hot vapour inlet (6) is adapted to communicate with the outlet of a vapour compression device.

2. The oily solvent vacuum evaporation unit of claim 1, wherein said heat exchange element (2) comprises two said heating channels, two said heating channels (18) are respectively arranged side by side on both sides of said condensing channel (20), said heat exchange element (2) further comprises a first heat exchange plate (8), a second heat exchange plate (9), a third heat exchange plate (10) and a fourth heat exchange plate (11);

the heat exchanger comprises a first heat exchange plate (8), a second heat exchange plate (9), a third heat exchange plate (10) and a fourth heat exchange plate (11), wherein the first heat exchange plate, the second heat exchange plate, the third heat exchange plate and the fourth heat exchange plate are sequentially arranged in parallel at intervals;

a bottom plate is connected between the bottom ends of the first heat exchange plate (8) and the second heat exchange plate (9) to form a first heating channel (18) between the two heat exchange plates, a bottom plate is connected between the bottom ends of the third heat exchange plate (10) and the fourth heat exchange plate (11) to form a second heating channel (18) between the two heat exchange plates, and the second oil-containing solvent inlet (12) is respectively arranged on the bottom plate of each heating channel (18);

the top ends and the bottom ends of the second heat exchange plate (9) and the third heat exchange plate (10) are respectively connected with a top plate and a bottom plate so as to form the condensation channel (20) between the two heat exchange plates; the solvent hot vapor second inlet (16) is arranged on the top plate of the condensation channel (20); the second outlet (17) of the liquid phase solvent is arranged on the bottom plate of the condensation channel (20).

3. The oleaginous solvent vacuum evaporation unit of claim 2, wherein the first, second, third and fourth heat exchange plates are each independently selected from one or more of stainless steel plates, carbon steel plates, titanium steel plates, polytetrafluoroethylene plates, copper plates, graphite plates and polyvinyl chloride plates.

4. The oleaginous solvent vacuum evaporation unit of claim 2, wherein the first, second, third and fourth heat exchange plates are each independently provided with a fluid passage on at least one side plate face.

5. The oily solvent vacuum evaporation unit of claim 1, wherein the heat exchange element (2) further comprises at least one secondary evaporation panel (21), and the secondary evaporation panel (21) is arranged outside the heating channel (18) and is parallel to and spaced apart from the side wall of the heating channel (18).

6. The oily solvent vacuum evaporation unit of claim 5, wherein the interval between the secondary evaporation panel (21) and the heating channel (18) is 0-5 cm.

7. The oleaginous solvent vacuum evaporation unit of claim 5, wherein the secondary evaporation panel is selected from one or more of steel plate, perforated steel plate, steel wire mesh grid, steel wire pressed block, polytetrafluoroethylene mesh grid and polytetrafluoroethylene wire pressed block.

8. The vacuum evaporation unit of claim 1, wherein the oily solvent vacuum evaporation unit (29) comprises a plurality of heat exchange elements (2) within the housing (1); a plurality of heat exchange elements (2) are arranged in the shell (1) at intervals along the axial direction; the heating channel of each heat exchange element (2) extends along the direction perpendicular to the axial direction of the shell and is spaced from the bottom of the shell.

9. The vacuum evaporation unit of claim 1, wherein the casing (1) is further provided with a start-up steam inlet (22), and the start-up steam inlet (22) is communicated with the second solvent hot steam inlet (16) of the heat exchange element (2) through a sealed pipeline.

10. Vacuum evaporation unit according to claim 9, wherein the housing (1) is further provided with a concentrate circulation outlet (23), the concentrate circulation outlet (23) being in communication with the heating channel (18) of the heat exchange element (2).

11. The vacuum evaporation unit of claim 10, wherein the concentrate circulation outlet (23) is in communication with the oily solvent first inlet (3) of the housing (1);

be equipped with concentrate delivery outlet (4) on casing (1), concentrate delivery outlet (4) are used for with the concentrated solution collection device intercommunication that contains oil.

12. The vacuum evaporation unit of claim 1, wherein a liquid level meter (24) is provided in the housing (1), the liquid level meter (24) being located close to and spaced from the bottom of the housing (1).

13. Vacuum evaporation unit according to claim 12, wherein the first side wall (25) of the housing (1) is provided with an access mounting opening (26).

14. Vacuum evaporation unit according to claim 13, wherein a pressure measurement device (38) is provided in the housing (1), the pressure measurement device (38) being adjacent to a second side wall (27) of the housing, the second side wall being located opposite to the first side wall.

15. The vacuum evaporation unit of claim 14, wherein the first inlet (6) for solvent-heated vapour is provided on the second side wall (27).

16. An oil-laden solvent recovery system, characterized in that the recovery system comprises a vapor compression unit (32) and an oil-laden solvent vacuum evaporation unit (29) of any one of claims 1 to 15;

wherein the vapour compression unit (32) comprises a vapour compression device (36); the outlet of the vapor compression device (36) is communicated with the first solvent vapor inlet (6) of the oil-containing solvent vacuum evaporation unit (29), and the inlet of the vapor compression device is communicated with the first solvent vapor outlet (5) of the oil-containing solvent vacuum evaporation unit (29).

17. An oleaginous solvent recovery system according to claim 16 characterized in that a pressure measuring device (38) is provided inside the casing (1); the vapour compression unit (32) further comprises second control means (37); the second control device (37) is respectively connected with the vapor compression device (36) and a pressure measuring device (38) of the oil-containing solvent vacuum evaporation unit (29) in a signal mode, so that the rotating speed of the vapor compression device (36) is controlled according to the pressure signal detected by the pressure measuring device (38).

18. An oleaginous solvent recovery system according to claim 16 wherein the casing (1) is provided with a concentrate outlet (4) and a concentrate recycle outlet (23); the oil-containing solvent recovery system also comprises a concentrated solution output unit (31) and a concentrated solution circulating unit (39);

wherein the concentrated solution output unit (31) comprises a concentrated solution output device (33) and a first control device (34), the inlet of the concentrated solution output device (33) is communicated with the concentrated solution output port (4) of the oily solvent vacuum evaporation unit (29), and the outlet of the concentrated solution output device (33) is communicated with an oily concentrated solution collecting device (35); the first control device (34) is in signal connection with the concentrated solution output device (33) and a liquid level meter (24) in the oily solvent vacuum evaporation unit (29) respectively, so as to control the rotating speed of the concentrated solution output device (33) according to a liquid level signal detected by the liquid level meter (24);

the concentrate circulating unit (39) comprises a concentrate circulating means (40), a flow measuring means (41) and a third control means (42); the inlet of the concentrated solution circulating device (40) is communicated with the concentrated solution circulating outlet (23) of the oily solvent vacuum evaporation unit (29), and the outlet of the concentrated solution circulating device (40) is communicated with the oily solvent first inlet (3) of the oily solvent vacuum evaporation unit (29); the flow measuring device (41) is arranged between the outlet of the concentrated solution circulating device (40) and the first inlet (3) of the oil-containing solvent; and the third control means (42) are in signal connection with the flow measuring means (41) and the concentrate circulating means (40), respectively, for controlling the rotational speed of the concentrate circulating means (40) in dependence of the flow signal detected by the flow measuring means (41).

19. An oleaginous solvent recovery system according to claim 18 wherein the concentrate recycle unit (39) further comprises a first valve (43) and a second valve (44); wherein the first valve (43) is arranged between the inlet of the concentrate circulating device (40) and the concentrate circulating outlet (23); the second valve (44) is arranged between the outlet of the concentrated solution circulating device (40) and the first inlet (3) of the oil-containing solvent;

the concentrated solution output unit (31) further comprises a third valve (45) and a fourth valve (46); wherein the third valve (45) is arranged between the inlet of the concentrated liquid output device (33) and the concentrated liquid output port (4); the fourth valve (46) is arranged between the outlet of the concentrated liquid output device (33) and the concentrated liquid collecting device (35);

in a concentrate circulating working state, the first valve (43) and the second valve (44) are opened, the third valve (45) and the fourth valve (46) are closed, the inlet of the concentrate circulating device (40) is communicated with the concentrate circulating outlet (23), and the outlet of the concentrate circulating device (40) is communicated with the first oily solvent inlet (3);

in the concentrated liquid discharging working state, the first valve (43) and the second valve (44) are closed, the third valve (45) and the fourth valve (46) are opened, the inlet of the concentrated liquid output device (33) is communicated with the concentrated liquid output port (4), and the outlet of the concentrated liquid output device (33) is communicated with the concentrated liquid collecting device (35);

in the concentrate circulation-discharge operation state, the first valve (43) and the second valve (44), the third valve (45) and the fourth valve (46) are opened, the inlet of the concentrate circulation device (40) is communicated with the concentrate circulation outlet (23), the outlet of the concentrate circulation device (40) is communicated with the oily solvent first inlet (3), the inlet of the concentrate output device (33) is communicated with the concentrate output port (4), and the outlet of the concentrate output device (33) is communicated with the concentrate collection device (35).

20. The system according to claim 16, further comprising a source of start-up vapor (47), wherein the source of start-up vapor (47) is in communication with the start-up vapor inlet (22) of the housing (1); a fifth valve (48) is arranged between the start-up steam source (47) and the start-up steam inlet (22);

in the start-up vapour operating state, the fifth valve (48) is open, the start-up vapour gas source is in communication with the start-up vapour inlet (22), and the outlet of the vapour compression device (36) is in communication with the first solvent vapour inlet (6), and the inlet of the vapour compression device (36) is in communication with the first solvent vapour outlet (5);

in the solvent hot vapour state, the fifth valve (48) is closed, placing only the outlet of the vapour compression device (36) in communication with the first inlet (6) of solvent hot vapour, and the inlet of the vapour compression device in communication with the first outlet (5) of solvent vapour.

21. An oil-contaminated solvent recovery system according to claim 20, characterized in that a pressure measuring device (38) is provided inside said casing (1); the opening and closing of the fifth valve (48) is determined on the basis of the rotational speed of the vapor compression device (36) and the detection data of the pressure measuring device (38).

22. A method for recovering an oily solvent, which comprises the steps of using the oily solvent recovery system according to any one of claims 16 to 21:

-letting the oily solvent to be recovered enter the heating channel of the heat exchange element (2) through the oily solvent first inlet (3), letting the solvent hot steam enter the condensing channel of the heat exchange element (2) through the solvent hot steam first inlet (6), and performing partition wall heat exchange with the oily solvent to be recovered to obtain an oily concentrated solution, solvent steam and a liquid phase solvent;

-passing said solvent vapour through a first solvent vapour outlet (5) into said vapour compression unit (32) for compression to obtain said hot solvent vapour.