FR3069173A1 - METHOD AND INSTALLATION FOR TREATING A LIQUID - Google Patents

Abstract

A method of treating a crude liquid (LB) containing dissolved solvents and non-volatile impurities, said method comprising providing a liquid treatment plant (1) comprising: - a first distillation column (10), - a second distillation column (20), - a device (30) for generating transport vapor (VT), in which process the solvents are extracted from the raw liquid (LB) in the first distillation column (10) by by means of the transport vapor (VT), the solvent-purified liquid comprising non-volatile impurities dropping in the lower part of the first distillation column (10) at the end of this stage being removed permanently from the installation (1), without entering the second distillation column (20) or the device (30) for generating transport vapor (VT).

Description

DESCRIPTION

The invention relates to a method and an installation for the treatment of liquids.

This method and this installation will find a particular application for the treatment of effluents containing dissolved solvents, such as for example ammonia, or else the treatment of petroleum liquids, and non-volatile impurities, such as salts or fouling substances.

In the field of effluent treatment, it is known to extract ammonia from water by carrying out a distillation.

The soiled product is introduced continuously into the upper part of a distillation column (also called a stripping column) and spreads under the effect of gravity by flowing on a support, such as for example a straw type filling. metallic, or a series of overlapping trays.

A transport stream, such as clean water vapor, is introduced at the bottom of the column. As it rises, this transport vapor exchanges and becomes charged with volatile solvent contained in the product, which therefore purifies.

The treated product is purified and recovered in the lower part of the column, while the outgoing transport vapor is condensed into a condensate highly charged with solvent.

The defect of such distillation column installations is their excessive energy consumption.

In order to overcome this drawback and propose a treatment installation whose energy efficiency is improved, it was proposed in patent application FR 2 939 051, filed by the Applicant, an installation for treating liquids, such as in particular effluents, containing dissolved solvents or petroleum products, comprising at least one distillation column, a device for generating a transport steam intended to supply said distillation column, and means for condensing the transport vapor leaving the condensate into a condensate said distillation column, and in which said distillation column forms at least one vertical treatment chamber, said installation having:

- means for introducing transport steam, at the bottom of the distillation column,

- means for introducing a liquid to be treated, in height, into said distillation column,

means for trickling support inside said at least one vertical treatment chamber to slow down the fall of liquid and increase the gas / liquid exchange surface in said chamber,

means for recovering the treated liquid which has dropped in the lower part of the distillation column,

Such an installation being remarkable in that the device for generating said transport steam has means for recovering the heat from the transport steam leaving said distillation column in order to vaporize a liquid to be vaporized, the device comprising:

an exchanger-evaporator comprising an inlet for the liquid to be vaporized, an inlet for a hot stream consisting of said transport steam leaving the distillation column and an outlet for the generated steam intended to feed said distillation column,

- Compressor means in order to compress either the vapor generated by the exchanger-evaporator, downstream from said exchanger-evaporator, or the transport vapor leaving said distillation column, upstream from said exchanger-evaporator.

Despite certain advantages, such an installation and the methods for treating liquids implemented using such an installation still have the disadvantage that, in the case where the liquid to be treated contains non-volatile impurities, such as salts, for example Sodium Chloride (NaCl) or also Potassium Chloride (KC1), in particular with a high concentration, typically greater than 30%, or even fouling materials, for example when it is leachate or phases liquids from anaerobic digestion, these salts or these fouling substances will be found at the base of the distillation column, because they will not be carried away by steam like dissolved solvents. Thus, the purified liquid loaded with nonvolatile impurities will be used as liquid to be vaporized in the exchanger-evaporator, which causes numerous inconveniences, including two major inconveniences:

- an ebullioscopic delay occurs in the exchanger-evaporator, because the salt concentration of the liquid increases the point of evaporation in the exchanger-evaporator,

- greater corrosion and fouling of the walls of the evaporator exchanger and / or the distillation column occurs due to the salt concentration and / or the presence of fouling materials.

These major inconveniences affect the proper functioning of such an installation, and degrade its energy efficiency, as well as its operating cost, in particular in that it may be necessary to increase the compression power in order to compensate for the ebullioscopic delay which intervenes in the exchanger, or also because it is necessary to increase the frequency of maintenance operations.

Thus, the present invention proposes to overcome the aforementioned drawbacks by proposing a treatment installation preventing any ebullioscopic delay in the exchanger and reducing the fouling and corrosion of the walls of the various elements of the installation, and in particular the exchanger, even when the raw liquid to be treated comprises salts (NaCl, or KC1) in high concentration.

The present invention relates to a method for treating a raw liquid, such as in particular effluents, containing dissolved solvents and non-volatile impurities, said method comprising the supply of a liquid treatment installation comprising:

- a first distillation column, known as the distillation column for raw liquids

- a second distillation column, known as the condensate distillation column

- a device for generating transport steam, comprising an evaporator-exchanger provided with a primary and a secondary, generating transport steam

The continuous treatment process comprising the simultaneous steps:

(a) Supply of the first distillation column of the installation with the raw liquid containing dissolved solvents and non-volatile impurities, said raw liquid not supplying the second distillation column, (b) Extraction of the solvents from the liquid crude in the first distillation column by means of the transport vapor, the liquid purified from the solvents and comprising non-volatile impurities dropping in the lower part of the first distillation column at the end of this step being permanently removed from the installation, (c) Supply of the exchanger-evaporator primary with transporting vapor charged with solvents from the first distillation column, in order to supply the heat necessary for the vaporization of a liquid in the secondary of the evaporator exchanger provided to form the transport vapor, (d) Vaporization in the secondary of the exchanger-evaporator of the liquid intended to form the transport vapor, the transport vapor loaded with solvents partially condensing into a condensate loaded with solvents in the primary of the evaporative exchanger, the vapor loaded with non-condensed solvents remaining in the primary of the exchanger-evaporator ( 30) being purged in order to be condensed, (e) Supply of the second distillation column with the condensate loaded with solvents from step (d) of vaporization in the exchanger-evaporator, (f) Solvent extraction condensate loaded with solvents in the second distillation column, the purified condensate being in recovery means in the lower part of the distillation column at the end of this step being transmitted to the exchanger-evaporator in order to constitute, at at least partially, the liquid to vaporize to form the transport vapor, (g) Supply of the primary exchanger-evaporator with the charged vapor e of solvents at the outlet of the second distillation column, in order to supply the heat necessary for the vaporization of the liquid intended to form the transport vapor, (h) Compression of the transport vapor upstream or downstream of the evaporator exchanger, by means of compressors in order to increase the enthalpy of the transport vapor used during steps (c) and (g), (i) Supply of the first distillation column and the second distillation column with the transport vapor produced in step (d).

According to optional characteristics, said method may have all or part of the following characteristics:

- the transport vapor and / or the liquid intended to be vaporized are purged from the exchanger-evaporator by means of a purge system during a step (J),

- the non-volatile impurities in the raw liquid with which the installation is fed during step (b) include a salt, such as sodium chloride or potassium chloride,

- the non-volatile impurities in the raw liquid with which the installation is supplied during step (b) include a fouling material.

The invention also relates to an installation for treating liquids, such as in particular effluents, containing dissolved solvents and non-volatile impurities, comprising:

- a device for generating transport steam,

- means for conveying liquids in the installation, provided for transporting raw liquids, not treated in the installation, containing non-volatile impurities,

a first distillation column, called a distillation column for raw liquids, forming at least one vertical treatment chamber,

- means for introducing a liquid to be treated, in height, into said first distillation column,

means for trickling support inside said at least one vertical treatment chamber to slow down the fall of liquid and increase the gas / liquid exchange surface in said chamber,

- means for introducing transport steam, at the bottom of the first distillation column,

means for recovering the treated liquid which has dropped in the lower part of the first distillation column,

- means for discharging the treated liquid which has dropped in the lower part of the first distillation column, said installation further comprising:

a second distillation column, known as the condensate distillation column, forming at least one vertical treatment chamber,

- means for introducing a liquid to be treated, in height, into said second distillation column,

- trickle support means inside said at least one vertical treatment chamber to slow down the fall of liquid and increase the gas / liquid exchange surface in said chamber,

- means for introducing transport steam, at the bottom of the second distillation column,

- Means for recovering the treated liquid which has fallen in the lower part of the second distillation column, installation in which said device for generating the transport steam has means for recovering the heat from the transport vapor leaving said first column distillation and said second distillation column in order to vaporize a liquid to be vaporized, said device comprising:

an exchanger-evaporator provided with a primary and a secondary, comprising an inlet for the liquid to be vaporized, an inlet for a hot stream consisting of said transport vapor charged with the solvents leaving the first distillation column and the second distillation column, an outlet for the transport vapor generated in the secondary of Γ exchanger-evaporator supplying said first distillation column and said second distillation column, and an outlet for the condensate loaded with solvents resulting from the condensation of the vapor transport leaving the first distillation column and the second distillation column in the primary of Γ exchanger-evaporator,

- compressor means in order to compress either the transport vapor generated in the secondary of Γ exchanger-evaporator, downstream of said exchanger-evaporator, or the transport vapor leaving said first distillation column and said second distillation column, upstream of said exchanger-evaporator, installation in which:

- Only said first distillation column receives the raw liquids, via the means for conveying the raw liquids into the installation, the raw liquids being supplied in the upper part of the first distillation column via the means of introduction of a liquid to be treated, and the purified liquids of solvents recovered in the lower part of the first distillation column, containing non-volatile impurities being evacuated via the evacuation means, without being transmitted to the second distillation column,

- Said second distillation column receives the condensate formed in the primary of the exchanger-evaporator, containing the solvents, the condensate being supplied in the upper part of the second distillation column by means of the introduction of a liquid to be treated .

According to optional characteristics, said installation may have all or part of the following characteristics:

- The evaporator-evaporator also has a dewatering outlet for the transport vapor which has supplied its heat to said evaporator-evaporator, and which is heavily loaded with solvents, and in which a condensation device, distinct from said evaporator-exchanger, makes it possible to condense the steam from said dewatering outlet,

- the secondary of the exchanger-evaporator is supplied with liquid to be vaporized, at the inlet, for the liquid to be vaporized by the liquid recovered in the lower part of the second distillation column by means of recovery means. liquid to spray,

the exchanger-evaporator takes the form of substantially vertical evaporation tubes arranged in a heating chamber, and has means ensuring the introduction of the transport vapor recovered in the chamber and heating the external wall of said evaporation tubes , means for introducing the liquid to be vaporized into the evaporation tubes at their upper part, as well as means for recovering the liquid having passed through the evaporation tubes, the primary of the exchanger being defined by the volume of the heating outside the tubes, the secondary defined inside the tubes.

Other purposes and advantages will appear in the description which follows which is given for information only and which is not intended to limit it.

The invention will be better understood on reading the following description accompanied by the attached drawings, among which:

FIG. 1 is a schematic view of a liquid processing installation according to the invention according to a first embodiment and capable of implementing the method according to the invention,

- Figure 2 is a schematic view of an installation according to a second embodiment and capable of implementing the method according to the invention.

The invention relates to a method for treating a raw liquid, such as in particular effluents, containing dissolved solvents and non-volatile impurities, said method comprising the supply of a liquid treatment plant 1 comprising:

a first distillation column 10, called the distillation column for raw liquids,

a second distillation column 20, called the condensate distillation column,

a device 30 for generating transport vapor VT, comprising an evaporator exchanger 30 provided with a primary 30P and a secondary 30S, generating a transport vapor VT.

According to the invention, the continuous treatment process comprises the simultaneous steps:

(a) Supply of the first distillation column 10 of the installation 1 with a raw liquid LB containing dissolved solvents and non-volatile impurities, the raw liquid not feeding the second distillation column 20, (b) Extraction of the solvents from the raw liquid LB in the first distillation column 10 by means of the transport vapor VT, the liquid purified from the solvents and containing the non-volatile impurities falling at the bottom of the first distillation column 10 to 1 'after this step being permanently removed from the installation 1, (c) Supply of the primary 30P of the exchanger-evaporator 30 with transport steam charged with VTS solvents from the first distillation column 10, in order to provide the heat necessary for the vaporization of an LV liquid intended to form the transport vapor LV, (d) Vaporization in the secondary 30S of the exchanger-evaporator 30 of the liquid e LV intended to form the transport vapor VT, the vapor charged with the solvents VTS partially condensing into a condensate CS charged with solvents forming in the primary 30P of the exchanger-evaporator 30, the vapor VTCS charged with solvents not condensed remaining in the primary 30P of the evaporator-exchanger 30 being purged with a view to being condensed, (e) Supply of the second distillation column 20 with the condensate CS charged with solvents from step (d) of vaporization in the exchanger-evaporator 30, (f) Extraction of the solvents from the condensate loaded with solvents CS in the second distillation column 20, the purified condensate CP being in recovery means 24 at the bottom of the distillation column 20 at the resulting from this step being transmitted to the exchanger-evaporator 30 in order to constitute, at least partially, the liquid to be vaporized LV to form the transport vapor VT, (g) Supply of the primary 30P of the exchanger-evaporator 30 with the vapor charged with solvents VTS at the outlet of the second distillation column 20, in order to supply the heat necessary for the vaporization of the liquid LV intended to form the transport vapor VT, (h ) Compression of the transport vapor VT upstream (vapor charged with solvents) or downstream (clean vapor) of the exchanger-evaporator 30, by means of compressing means 40 in order to increase the enthalpy of the vapor of VT transport used during steps (c) and (g), (i) Supply of the first distillation column 10 and the second distillation column 20 with the transport vapor VT produced in step (d).

Such a process with these steps carried out simultaneously, allows said installation 1, shown in the exemplary embodiments of FIGS. 1 and 2, to treat a raw liquid containing solvents and non-volatile impurities continuously.

Advantageously, and since the non-volatile impurities are removed definitively from the installation 1 during step (b), which takes place in the first distillation column 10, these will not be found at any time in the other elements. of said installation 1, and in particular in the second distillation column 20, and especially the exchanger-vaporizer 30.

The operation of these elements 20, 30 is therefore not disturbed by the presence of these non-volatile impurities and said installation will not suffer from the problems identified with the installations of the state of the art, namely:

an ebullioscopic delay occurring in the exchanger-evaporator 30, because the concentration of non-volatile impurities, in particular salts, of the liquid to be treated increases the point of evaporation in the exchanger-evaporator 30: the invention makes it possible to s ensuring that the liquid purified from the solvents and containing the salts recovered at the base of the first distillation column 20 does not reach the exchanger-evaporator 30,

- greater corrosion and fouling of the walls of the evaporator exchanger 30 and / or of the second distillation column 20 occurs due to the salt concentration and / or the presence of fouling materials.

Thus, the energy efficiency of the process and of the installation will be significantly improved compared to the state of the art, and the operating cost of the installation will be reduced.

In fact, it will not be necessary to increase the quantity of vapor to be supplied to the exchanger-evaporator to counter the ebullioscopic delay caused by the presence of non-volatile impurities in order to obtain satisfactory evaporation of the LV liquid vaporized in the exchanger-evaporator 30.

In addition, the walls of the secondary 30S, by the exchanger-evaporator 30, as well as those of the second distillation column 20 or even compressor means 40, will not be clogged with non-volatile impurities, which decreases the maintenance needs of these elements and therefore the operating cost of said installation 1.

The stage (h) of compressing the transport vapor VT, VTS advantageously makes it possible to limit the steam requirements of the installation 1 for implementing the method according to the invention. Indeed, thanks to this compression step (h), the enthalpy of the vapor is increased, and therefore its temperature and its pressure, which makes it possible to be able to reuse it during steps (b) and (f) of extraction of the solvents, intervening respectively in the first distillation column 10 and in the second distillation column 20, and therefore to limit injecting new vapor into the installation 1 to implement the process.

According to a first embodiment, represented for example in FIG. 1, step (h) of compression of the transport vapor VT can be carried out by compressor means 40, comprising for example a mechanical compressor, arranged downstream of the exchanger-evaporator 30 and upstream of the first distillation column 10 and the second distillation column 20. In such an embodiment, the compressor means 40 will perform compression on transport vapor VT, purified from solvents .

According to a second embodiment, shown for example in FIG. 2, step (h) of compressing the transport steam VTS can be carried out by compressor means 40, comprising for example a mechanical compressor, arranged upstream of the exchanger-evaporator 30, and downstream of the first distillation column 10 and the second distillation column 20. In such an embodiment, the compressor means 40 will carry out a compression on transport vapor VTS, charged with solvents.

According to one embodiment, the transport vapor VT and / or the liquid LV intended to be vaporized are purged from the exchanger-evaporator 30 by means of a purge system 60 during a step (j) .

As can be seen in the exemplary embodiments of FIGS. 1 and 2, the transport vapor VT can be purged at an outlet 35 for transport vapor VT from the exchanger-evaporator 30, in particular an outlet 35 for transport vapor VT purified, ie not containing solvents, for example upstream of the second distillation column 20 and the first distillation column 10.

The transport steam VT thus purged can optionally be used to supply a steam supply network separate from said installation L

As can be seen in the exemplary embodiments of FIGS. 1 and 2, the LV liquid to be vaporized can be purged at an outlet for the LV liquid to be vaporized from the exchanger-evaporator 30, in particular an outlet for the purified LV liquid to be vaporized, ie not containing solvents, for example downstream of the second distillation column 20 and upstream of the exchanger-evaporator 30.

The liquid LV sprayed in this way can optionally be used to supply a liquid supply network separate from said installation L

Such a step (j) of purging the transport vapor VT and / or the liquid LV intended to be vaporized advantageously makes it possible to adjust the supply of transport vapor VT and / or in liquid to be vaporized LV of the installation 1 implementing the method according to the invention, for example in order to avoid overheating of the first 10 and / or of the second distillation column, because of too great a quantity of transport vapor VT received.

According to one embodiment, the non-volatile impurities of the raw liquid LB with which the installation 1 is supplied during step (b) comprise a salt, such as sodium chloride or potassium chloride.

As explained above, the salts contained in the raw LB liquids to be treated can degrade the operation of an installation implementing a liquid treatment process. Indeed, such salts, will tend to create an ebulioscopic delay at the level of the steam generator device, the LV liquid intended to be vaporized, although no longer containing solvents, still contains the salts, which are not volatile particles , and which cannot be extracted from a liquid via a distillation column.

Furthermore, such salts can generate fouling or corrosion of the various elements of the installation implementing a liquid treatment process.

Thanks to the process according to the invention, the salts are definitively removed from the installation 1 at the end of step (b), which occurs in the first distillation column 10, which becomes the only element of the installation to come into contact with the salts during the process according to the invention, thus having a "buffering effect" for the rest of the installation 1, the elements of which, in particular the second distillation column 20, or even the exchanger-evaporator 30, will not come into contact with said salts.

According to one embodiment, the non-volatile impurities of the raw liquid LB with which the installation 1 is supplied during step (b) comprise a fouling material.

As explained above, such a fouling material can consist of a leachate, or even a liquid phase of an anaerobic digestion.

Such fouling materials have harmful effects for an installation making it possible to implement a process for treating a liquid, similar to those of the salts described above.

Thus, thanks to the method according to the invention, the fouling material will only come into contact with the first distillation column 10 of the installation 1, and will be permanently removed from the installation 1 at the end of the step. (b), preventing it in particular from fouling the other elements 20, 30 of the installation 1.

The invention also relates to an installation for treating liquids 1, such as in particular effluents, containing dissolved solvents and non-volatile impurities, comprising and suitable for carrying out the process described above:

- a device for generating a transport vapor 30,

means for conveying liquids 11 in installation 1, provided for transporting raw LB liquids, not treated in installation 1, containing non-volatile impurities,

a first distillation column 10, known as the distillation column for raw liquids, forming at least one vertical treatment chamber,

means for introducing 11 an LB liquid to be treated, in height, into said first distillation column 10,

runoff support means 12 inside said at least one vertical treatment chamber to slow down the fall of liquid and increase the gas / liquid exchange surface in said chamber,

- means 13 for introducing transport vapor VT, in the lower part of the first distillation column 10,

means 14 for recovering the treated liquid which has dropped in the lower part of the first distillation column 10,

- means 15 for evacuating the treated liquid which has dropped in the lower part of the first distillation column 10, said installation further comprising:

a second distillation column 20, called the condensate distillation column, forming at least one vertical treatment chamber,

means 21 for introducing a liquid to be treated, in height, into said second distillation column 20,

- trickle support means 22 inside said at least one vertical treatment chamber to slow down the fall of liquid and increase the gas / liquid exchange surface in said chamber,

- means 23 for introducing the transport vapor VT, in the lower part of the second distillation column,

means 24 for recovering the treated liquid which has dropped at the bottom of the second distillation column 20.

According to the invention, said device 30 for generating the transport vapor VT has means 33 for recovering the heat from the transport vapor VTS leaving said first distillation column 10 and said second distillation column 20 in order to vaporize a liquid to be vaporized, said device 30 comprising:

an exchanger-evaporator 30 provided with a primary 30P and a secondary 30S, comprising an inlet 31 for the LV liquid to be vaporized, an inlet 33 for a hot stream consisting of said transport vapor VTS leaving the first column of distillation 10 and from the second distillation column 20, an outlet for the transport vapor VT generated in the secondary 30S of the exchanger-evaporator 30 supplying said first distillation column 10 and said second distillation column 20, and an outlet 34 for the condensate charged with solvents CS resulting from the condensation of the transport vapor VTS leaving the first distillation column 10 and the second distillation column 20 in the primary 30P of the exchanger-evaporator 30,

- compressor means 40 in order to compress either the transport vapor VT generated in the secondary 30S of the exchanger-evaporator 30, downstream of said exchanger-evaporator 30, or the transport vapor VTS leaving said first distillation column 10 and said second distillation column 20, upstream of said exchanger-evaporator 30.

According to the invention:

- Only said first distillation column 10 receives the raw liquids LB, via the means 11 for conveying the raw liquids LB in the installation 1, the raw liquids LB being supplied at the top of the first distillation column 10 via the means 11 for introducing a liquid to be treated LB, and the liquids purified from the solvents (LI) recovered in the lower part of the first distillation column 10, containing non-volatile impurities, being discharged by l 'intermediate the discharge means 15, without being transmitted to the second distillation column 20,

- Said second distillation column 20 receives the condensate CS formed in the primary 30P of the exchanger-evaporator 30, containing the solvents, the condensate CS being supplied in the upper part of the second distillation column 20 via the means d introduction 21 of a liquid to be treated.

Such an installation 1 can advantageously implement the method for treating a liquid according to the invention described above.

Such an installation 1 also has the advantage that non-volatile impurities, such as salts, for example NaCl or KC1, or fouling materials, such as leachate or methanization digestates, by being removed at the first distillation column 10 of said installation 1 does not come into contact with the other elements of the installation, in particular the second distillation column, the exchanger-evaporator 30 or even the compressor means 40.

Thus, an ebullioscopic delay is not generated by these volatile impurities in the evaporator exchanger and the walls of the elements of the installation, other than those of the first distillation column 10 are not fouled or corroded by these impurities.

Said means 12, 22 runoff support can be, in a manner known per se, in the form of superimposed trays or also in the form of a metal straw type lining.

We describe below the two exemplary embodiments illustrated respectively in FIG. 1 and in FIG. 2. These two embodiments are distinguished substantially by the position of the compressor means 40 in the installation 1.

Each of the distillation columns 10, 20 forms a treatment chamber.

The raw liquid LB to be treated, comprising solvents and non-volatile impurities, is continuously conveyed to installation 1 by means 11 of conveying liquids in installation 1.

The raw liquid LB to be treated is then introduced by the introduction means 11, in height, at the top of the first distillation column 10, while the transport vapor VT is introduced by the introduction means 13 to the lower part of the first distillation column 10.

Going back up in the first distillation column 10, the transport vapor VT exchanges with the raw liquid LB to be treated and is loaded with solvents.

The non-volatile impurities are not carried by the transport vapor VT in the first distillation column 10 to the upper part of said first distillation column 10, but are recovered in a condensate L1 containing the non-volatile impurities, in the lower part of said first distillation column 10 by means of recovery 14 before being evacuated by means of evacuation 15, while the transport vapor VTS, loaded with solvents, is evacuated, in the upper part, of the first distillation column 10, by means 16 of evacuation of the transport steam VTS.

Thus, the non-volatile impurities will be definitively removed from installation 1 and will not interact with the other elements of installation 1.

The transport vapor VTS charged with solvents, recovered in the upper part of the first distillation column is then chimney towards the steam generation device 30.

As can be seen in the exemplary embodiments of FIGS. 1 and 2, the steam generation device 30 comprises an exchanger-evaporator 30 comprising an inlet for the liquid to be vaporized LV, an inlet 33 for a hot stream constituted by the transport steam VTS leaving the first distillation column 10 and leaving

39s for the vapor VT generated by said exchanger-evaporator 30 and intended to supply the first distillation column.

Said exchanger-evaporator is advantageously provided with a primary 30P, intended to receive the transport vapor VTS charged with solvents, which will bring the heat to the liquid to be vaporized LV, and a secondary 30S intended to receive the liquid LV to be vaporized.

Means 39i for recovering the transport vapor VT make it possible to recover the transport vapor VT, purified at the outlet of the secondary 30S of the exchanger-evaporator 30, in order to supply the first distillation column 10 and the second distillation column 20. An outlet 35 for transport vapor VT is provided at the bottom of the exchanger-evaporator and communicates with the means 13, 23 for introducing the transport vapor VT at the bottom of the first distillation column 10 and the second distillation column 20.

An outlet 34 is provided for extracting the condensate CS charged with solvents recovered in the lower part of the primary 30P of the exchanger-evaporator 30 and supplying the second distillation column 20, in the upper part, via the supply means 21 of the second distillation column 20 in LT liquid to be treated, said liquid not comprising non-volatile impurities.

The second distillation column 20 comprises means 23 for introducing the transport vapor VT to the lower part of the second distillation column 20.

Going back up in the second distillation column 20, the transport vapor VT exchanges with the liquid LT to be treated and is loaded with solvents coming from the condensate CS coming from the exchanger-evaporator 30.

The second distillation column 20 also comprises means 25 for evacuation of the transport vapor VTS, loaded with solvents, in the upper part of the second distillation column 20 in order to supply the primary 30P of the evaporator exchanger 30 by l 'intermediate means 33 for recovering the heat of the transport steam VTS.

It should be noted that according to these exemplary embodiments, part of the condensation of the VTS transport vapors loaded with solvents takes place in said evaporator exchanger 30 which has means for recovering the condensate produced in said exchanger-evaporator 30, and means 34 for conveying it to the upper part the second distillation column 20 in order to carry out a new extraction of the solvents.

According to the embodiment of FIG. 1, the compressor means 40, which for example comprise a mechanical compressor, or even a thermocompressor, are provided for compressing the transport vapor VT, purified of solvents, generated by the exchanger-evaporator 30, which is conveyed to the means 13, 23 for introducing the first distillation column 10 and the second distillation column 20.

According to a second embodiment, visible in the embodiment of FIG. 2, the compressor means 40, which can also include a mechanical compressor, or even a thermocompressor, are provided for compressing the transport vapor VTS, loaded with solvents , between the means 16, 25 for recovering the transport vapor VTS, loaded with solvents, in the upper part of the first distillation column 10 and the second distillation column and the inlet for the transport vapor VTS, charged with solvents, exchanger-evaporator 30.

According to this second embodiment, the compressor means 40 do not compress the clean transport vapor VT (ie purified from solvents), as illustrated in the embodiment of FIG. 1, but the transport vapor VTS, charged solvents.

Advantageously, as can be seen in the exemplary embodiments of FIGS. 1 and 2, a purge system 60 may be provided in said installation 1 in order to purge the liquid to be vaporized LV, for example upstream of the exchanger-evaporator 30, and / or the transport vapor VT, for example downstream of the evaporator-evaporator 30.

According to one embodiment, the exchanger-evaporator 30 has, in addition, a dewatering outlet 36 for the VTCS transport vapor having supplied its heat to said exchanger-evaporator, and heavily loaded with solvents, and in which a device for condensation 50, distinct from said exchanger-evaporator 30, makes it possible to condense the VTCS vapor coming from said dewatering outlet 36.

Said condensing device 50 can for example be a condensing air heater.

In this device 50, the condensates, highly enriched in solvent, are wholly or partly recycled or extracted from said installation 1, in particular by undergoing fractional condensation.

According to the embodiment of FIGS. 1 and 2, the liquid to be vaporized LV in said exchanger 30 is the purified liquid LV recovered in the lower part of the second distillation column 20 and which is conveyed by means 26 to 1 entry 31 of said exchanger-evaporator 30.

According to one embodiment, the secondary 30S of the exchanger-evaporator 30 is supplied with liquid to be vaporized LV, at the level of the inlet 31 for the liquid to be vaporized, by the liquid LV recovered in the lower part of the second column of distillation 20 via the means 24 for recovering liquid to be vaporized LV.

As can be seen in the exemplary embodiments of FIGS. 1 and 2, said second distillation column 20 also includes means 24 for recovering the LV treated liquid having fallen in the lower part of the second distillation column 20, said LV liquid being purified from solvents , and being intended to supply the secondary 30S of the exchanger-evaporator 30, at the level of the inlet 31, by means of supply means 26. This LV liquid is obviously purified of any non-volatile impurity, because it has already passed through the first distillation column 10.

According to one embodiment, the secondary 30S of the exchanger-evaporator 30 takes the form of substantially vertical evaporating tubes 37 arranged in a heating chamber 38 constituting the primary 30P of the exchanger-evaporator 30, and has means 33 ensuring the introduction of the VTS transport vapor recovered in the chamber 38 and heating the external wall of said evaporation tubes 37, means

39s for introducing the LV liquid to be vaporized into the evaporation tubes 37 at their upper part, as well as means 39i for recovering the LV liquid having passed through the evaporation tubes, the primary 30P of the exchanger being defined by the volume heating chamber 38 outside the tubes 37, the secondary 30S defined inside the tubes 37.

This exchanger-evaporator, visible in the exemplary embodiments of FIGS. 1 and 2, operates in the following manner.

The purified water LV having dropped at the bottom of the second distillation column 20 is recovered and introduced by the means 39s into the evaporation tubes 37 of the secondary 30S at their upper part. This water, under the combined action of capillarity and gravity trickles inside the evaporation tubes, and is partially vaporized thanks to the heat transmitted by the wall of the tubes 37.

The vapor VT produced descends in the tubes 37 and is evacuated by the outlet 35 while a part of the liquid LV crosses the tubes 37 and is evacuated at their lower part to be recovered in the means 39i; this is LV treated water, purified from solvents. The clean vapor VT generated by the exchanger-evaporator 30 is conveyed to the said introduction means 13, 23 of the first 10 and of the second distillation column, possibly being compressed by the compressor means 40.

The method and the installation in accordance with the invention will find a particular application in particular for:

- the treatment of animal manure (which contains, in addition to the dry matter, water and ammonia),

- the treatment of discharge leachate (which contains, in addition to the dry matter, water and ammonia),

- the treatment of petroleum liquid (which contains different solvents at different boiling points) including the refining of gasolines.

Other embodiments could have been envisaged by the skilled person without departing from the scope of the invention defined by the claims below.

NOMENCLATURE

I. Installation

LB. Raw liquid

LT. Liquid to be treated

LV. Liquid spray

Ll. Liquid loaded with non-volatile impurities

CS. Solvent-laden condensate

VT. Transport steam

VTS. Transport steam loaded with solvents

VTCS. Transport vapor heavily loaded with solvents

10. First distillation column

20. Second distillation column

II, 21. Means for introducing liquid

12, 22. Runoff support means

13, 23. Means for introducing transport steam

14, 24. Means to recover treated

15, Means of evacuation of non-volatile impurities

16, 25. Means for removing solvent-laden steam

26. Means for supplying liquid

30. Steam generation device / Evaporator-evaporator

0L. Primary

3os. Secondary

31. Input for the liquid to be vaporized

33. Input for hot flow

34. Outlet for condensate loaded with solvents

35. Outlet for transport steam

36. Exit of dewatering

37. Tubes

38. Heating chamber

39i. Means for recovering the liquid to be vaporized

39s. Means for introducing the liquid to be vaporized

40. Compressor means

50. Condensing device

60. Purge system

Claims (8)

1. Method for treating a raw liquid, such as in particular effluents, containing dissolved solvents and non-volatile impurities, said method comprising the supply of a liquid treatment installation (1) comprising: - a first distillation column (10), called the distillation column for raw liquids - a second distillation column (20), called the condensate distillation column - a device (30) for generating transport vapor (VT), comprising an exchanger-evaporator (30) provided with a primary (30P) and a secondary (30S), generating transport vapor (VT) The continuous treatment process comprising the simultaneous steps: (a) Supply of the first distillation column (10) of the installation (1) with the raw liquid (LB) containing dissolved solvents and non-volatile impurities, said raw liquid (LB) not supplying the second distillation column (20), (b) Extraction of the solvents from the raw liquid (LB) in the first distillation column (10) by means of the transport vapor (VT), the liquid purified from the solvents and comprising the impurities non-volatiles falling in the lower part of the first distillation column (10) at the end of this step being permanently removed from the installation (D, (c) Primary supply (30P) of the exchanger-evaporator (30 ) with solvent-laden transport steam (VTS) from the first distillation column (10), in order to provide the heat necessary for the vaporization of a liquid (LV) in the secondary (30S) of the exchanger -evaporator (30) provided to form the steam of tran sport (LV), (d) Vaporization in the secondary (30S) of the exchanger-evaporator (30) of the liquid (LV) intended to form the transport vapor (VT), the transport vapor loaded with solvents partially condensing in a condensate (CS) charged with solvents in the primary (30P) of the exchanger-evaporator (30), the vapor (VTCS) charged with non-condensed solvents remaining in the primary (30P) of the exchanger-evaporator (30 ) being purged in order to be condensed, (e) Supply of the second distillation column (20) with the condensate (CS) loaded with solvents from step (d) of vaporization in the exchanger-evaporator (30 ), (f) Extraction of the solvents from the solvent-laden condensate (CS) in the second distillation column (20), the purified condensate (CP) being in recovery means (24) at the bottom of the distillation column (20) at the end of this step being transmitted to the exchanger-evaporator ( 30) in order to constitute, at least partially, the liquid to be vaporized (LV) to form the transport vapor (VT), (g) Supply of the primary (30P) the exchanger-evaporator (30) with the vapor charged with solvents (VTS) at the outlet of the second distillation column (20), in order to provide the heat necessary for the vaporization of the liquid (LV) intended to form the transport vapor (VT), (h) Compression of the transport vapor ( VT) upstream or downstream of the evaporator exchanger (30), by means of compressor means (40) in order to increase the enthalpy of the transport vapor (VT) used during steps (c) and ( g), (i) Supply of the first distillation column (10) and the second distillation column (20) with the transport vapor (VT) produced in step (d). 2. Method according to claim 1, in which the transport vapor (VT) and / or the liquid (LV) intended to be vaporized are purged from the exchanger-evaporator (30) via a system of purge (60) during a step (k). 3. Method according to claim 1 wherein the non-volatile impurities of the raw liquid (LB) with which the installation is fed (1) during step (b) comprise a salt, such as sodium chloride or potassium chloride. 4. Method according to claim 1 or 2, wherein the non-volatile impurities of the raw liquid (LB) with which the installation is fed (1) during step (b) comprise a fouling material. 5. Installation for treating liquids (1), such as in particular effluents, containing dissolved solvents and non-volatile impurities, comprising: - a device for generating a transport vapor (30), - means for conveying (11) liquids in the installation (1), intended to convey raw liquids (LB), not treated in the installation (1), containing non-volatile impurities, a first distillation column (10), known as the distillation column for raw liquids, forming at least one vertical treatment chamber, - means for introducing (11) a liquid to be treated, in height, into said first distillation column (10), runoff support means (12) inside said at least one vertical treatment chamber to slow down the fall of liquid and increase the gas / liquid exchange surface in said chamber, - means (13) for introducing transport steam (VT), in the lower part of the first distillation column (10), means (14) for recovering the treated liquid which has dropped in the lower part of the first distillation column (10), - Means (15) for evacuating the treated liquid which has dropped in the lower part of the first distillation column (10), said installation further comprising: a second distillation column (20), called the condensate distillation column, forming at least one vertical treatment chamber, - means (21) for introducing a liquid to be treated, in height, into said second distillation column (20), - trickle support means (22) inside said at least one vertical treatment chamber to slow down the fall of liquid and increase the gas / liquid exchange surface in said chamber, - means (23) for introducing transport steam (VT), in the lower part of the second distillation column, - Means (24) for recovering the treated liquid which has dropped in the lower part of the second distillation column (20), installation in which said device (30) for generating transport steam (VT) has means (33) for recovering the heat of the transport vapor (VTS) leaving said first distillation column (10) and said second distillation column (20) in order to vaporize a liquid to be vaporized, said device (30) comprising: - An exchanger-evaporator (30) provided with a primary (30P) and a secondary (30S), comprising an inlet (31) for the liquid to be vaporized, an inlet (33) for a hot flow made up of said vapor transport (VTS) loaded with solvents leaving the first distillation column (10) and the second distillation column (20), an outlet for the transport vapor (VT) generated in the secondary (30S) of the exchanger -evaporator (30) supplying said first distillation column (10) and said second distillation column (20), and an outlet (34) for the condensate loaded with solvents (CS) resulting from the condensation of the transport vapor ( VTS) leaving the first distillation column (10) and the second distillation column (20) in the primary (30P) of the exchanger-evaporator, - compressor means (40) in order to compress either the transport vapor (VT) generated in the secondary (30S) of the exchanger-evaporator (30), downstream of said exchanger-evaporator (30), or the transport vapor (VTS) leaving said first distillation column (10) and said second distillation column (20), upstream from said exchanger-evaporator (30), installation in which: - Only said first distillation column (10) receives the raw liquids (LB), via the means (11) for routing the raw liquids (LB) in the installation (1), the raw liquids (LB) being supplied in the upper part of the first distillation column (10) by means (11) of introducing a liquid to be treated (LB), and the purified liquids of the solvents (L1) recovered in the lower part of the first distillation column (10), containing non-volatile impurities being discharged via the evacuation means (15), without being transmitted to the second distillation column (20), - Said second distillation column (20) receives the condensate (CS) formed in the primary (30P) of the exchanger-evaporator (30), containing the solvents, the condensate (CS) being supplied at the top of the second column distillation (20) by means of introduction (21) of a liquid to be treated. 6. Installation (1) according to claim 5, wherein the exchanger-evaporator (30) has, in addition, a dewatering outlet (36) for the transport vapor (VTCS) having supplied its heat to said exchanger-evaporator , and heavily loaded with solvents, and in which a condensing device (50), distinct from said exchanger-evaporator (30), makes it possible to condense the vapor (VTCS) coming from said dewatering outlet (36). 7. Installation (1) according to claim 5 or 6, wherein the secondary (30S) of the exchanger-evaporator (30) is supplied with liquid to be vaporized (LV) at the inlet (31) for the liquid to be vaporized by the liquid (LV) recovered in the lower part of the second distillation column (20) via the means (24) for recovering liquid to be vaporized (LV). 8. Installation (1) according to one of claims 5 to 7, wherein the evaporator exchanger (30) takes the form of substantially vertical evaporating tubes (37) disposed in a heating chamber (38) and has means (33) ensuring the introduction of the transport vapor (VTS) recovered in the chamber (38) and heating the external wall of said evaporation tubes (37), means (39s) for introducing the liquid to be vaporized (LV) in the evaporation tubes (37) at their upper part, as well as means (39i) for recovering the liquid (LV) having passed through the evaporation tubes, the primary (30P) of the exchanger being defined by the volume 5 heating chamber (38) outside the tubes (37), the secondary (30S) defined inside the tubes (37).