DE3334420A1 - Process and apparatus for separating thermally sensitive multi-component mixtures in vacuum - Google Patents

Abstract

The invention relates to a process and an apparatus for separating degassed and dewatered thermally sensitive multi-component mixtures in vacuum. The aim and object of the invention are to ensure the attainment of high yields of a colour-stable main fraction of good quality with complete separation of residue and first runnings and with low consumption of energy and low expenditure in terms of apparatus. The object is achieved according to the invention in that the multi-component mixture is divided into two fractions at 300 to 500 Pa, from which, at 100-200 Pa, by evaporation and condensation and circulation of the vapours containing non-condensing first runnings, a first main fraction, the residue, a second main fraction and, if present in the multi-component mixture, first runnings are successively condensed. The separation of this multi-component mixture is carried out in only one column which is furnished with external and internal heat exchanger surfaces and is subdivided by chambers into a plurality of functional spaces. The vapour velocities in counter-current flow are 30 to 50 m/s. The first runnings fractions can be removed to a level lower than 0.1%, for which purpose only small reflux rates are required.

Description

Method and device for the separation of thermal

sensitive multicomponent mixtures in a vacuum The invention relates to a method and a device for the separation of thermally sensitive multicomponent mixtures in vacuum, especially for the flow, main run and residue separation from thermal sensitive split fats of vegetable and animal origin.

In addition, the procedure can be applied where the forerun and test residue separations must be subjected to rectification conditions, how to. during the distillation of caprolactam, essential oils, synthetic Fatty acids, tall oil, amines, fatty alcohols, etc. Die by splitting vegetable oils Crude fatty acids obtained from animal fats contain water as well as water dissolved air and in the subsequent thermal work-up as a result of thermal cleavage or / and auto-oxidation resulting, non-condensable at normal pressure low-boiling organic compounds. Autoxydatiora can result in storage and through hydrolytic cleavage of the fats form further cleavage products, which to a large extent the smell, the color, the flit resistance and the chemical parameters of the fission fatty acids influence.

The thermal processing of the degassed and dehydrated fatty acids must be done in such a way that the distillation takes place under conditions under which a thermal or autoxidative damage with renewed formation easier and heavier fission products as far as possible to avoid. the today everywhere required high yield of distillable fatty acids with best Quality leads, especially when processing inferior raw materials as a result the high-boiling color carriers and other organic substances contained in the residues Impurities, to additional equipment and process engineering effort.

Fission fatty acids are worked up on an industrial scale by distillation in the processing stages of degassing / dewatering, flow separation, main flow and tail separation. It is used for degassing / dewatering and flow separation Usually, an apparatus consisting of an 8 m long continuous falling film evaporator as a stripping section and a 5 m long packed column or tray column with 10 To use bell bottoms as a reinforcement part. There is one at the top of the column Separation device in which the water is separated from the fatty acids and the majority of the light fatty acid phase as reflux to the column is given. The distillation pressure is 13,300 Pa and the temperature in the stripping section is between 180 and 220 OC. The reflux ratio will range from 40 to 200 regulated. (Stage, H.

Fats, soaps, paints 82, Volume No. 9, pp. 338 - 339) DE-OS 2352859) The main and trailing lines are separated in straight stages that are passed through one after the other. In the main stage, up to 90% of the distillable components are evaporated and converted into the final stage is about 40% distillate. (Stage, H .: Fats, soaps, paints, Jg. 76, 197 1974 p. 250) To avoid unwanted entrained passing over Components such as paint carriers and unsaponifiable components are these columns provided with separators and the effective steam velocities are kept in the range from 3 to max. 6 m / s. It is also customary to use that from the degassing / dewatering stage draining product in a relaxation room, in which the steam speed kept slightly below 1 m / s comparable air speed to guide the not- evaporated part in the lower left part of the relaxation room arranged main film evaporator subjected to a further evaporation and here non-evaporated portion to a falling-film evaporator located on the right of the expansion space is supplied for residual evaporation. To avoid mechanical entrainment of non-evaporated Liquid particles or the more concentrated in residue drain through the fatty acid vapors flowing upwards from the relaxation room to the condensation zone, is a droplet separator in addition to maintaining low steam speeds Euroform separator "provided.

(Stage, H .: Fette, Seifen, Anstrichmittel 82, Volume 9 1980 S 345 - 346) (DE-OS 2736357) is also known a method with a device according to DD-PS 91 800, where the degassing / dewatering in a single or multi-stage falling film countercurrent device is carried out and the main and tailings separation in a downstream Device expires. In this system, steam speeds of up to 6 m / s natural fatty acids are distilled with high yield, with no additional separation devices color-stable distillates are obtained.

(Gutwasser, H.:; Voss, B .: Chem. Technik November 1981) As far as necessary, the stripped distillates are then rectified in the main run frees unwanted first and low-boiling fatty acids. With the well-known Process for main and tail separation, an energy requirement of 100% based on the one-time evaporation.

For the flow separation, the energy requirement increases as a function of the raw mixture properties and the separation process used by 20 to 30 %, based on the one-time evaporation.

The separation of transferred color bodies and other impurities as well as the low steam speed in the column space are essential in all of these processes complex equipment and fixtures.

The desired high yield, especially with qualitative bad Raw products can only be achieved by reducing the quality of the end products.

The aim of the invention is the separation of thermally sensitive multicomponent mixtures in the forerun, main run and residue with little energy and equipment expenditure.

The invention is based on the object of a method and a device for the separation of dehydrated and degassed thermally sensitive multicomponent mixtures to develop in the forerun, main run and residue, resulting in a high yield of color-stable Main run of good quality with complete separation of the residue and the forerun can be guaranteed.

According to the invention, the object is achieved in that degassed from a and dewatered raw mixture to which the condensate from a first condensation phase is added as a circulation amount, in a first partial evaporation via the phase equilibrium in addition, full flow portions as well as in a second partial evaporation with less Pressure can be evaporated in a first main run and in a third partial evaporation a follow-up evaporation and residue separation takes place, whereupon the vapors of the first and third partial evaporation are merged and these vapors in the first condensation phase on outer surfaces is the rectifying evaporation the flow portions and separation of a second main run from the condensate a second condensation phase of these vapors by partial re-evaporation twice causes on inner surfaces and the second condensation phase, which in turn occurs on outer surfaces Areas takes place, the evaporation of the first main run from the raw mixture, so causes the second partial evaporation on inner surfaces, with a portion of the Flow and the light product from the second re-evaporation running down below be added to the condensate of the second condensation phase as a circulating amount.

According to the invention this is done in that from the raw mixture, the the lead-free, originating from a first condensation phase described later Condensate is mixed in as a circulation amount, in one or more Fall film or thin-film evaporators with external heat input in a first partial evaporation Beyond the phase equilibrium, all flow components under a pressure of 380 evaporate up to 420 Pa and are fed to a special column at the bottom. The unevaporated Raw mixture is fed to the inner surfaces of a downstream heat exchanger, in which, in a second partial evaporation, which is followed by a described second condensation phase is effected, the evaporation of a first Main run under a pressure of 100 to 200 Pa and a steam speed of 20 to 40 m / s takes place, which is condensed and discharged. The remaining raw mixture now gets into another or more falling film heated with external energy or thin-film evaporators at 380 to 420 Pa for the third partial or follow-up evaporation and is evaporated down to the residue. The vapor of the third partial evaporation is also fed to the bottom of the special column and the residue runs off.

The vapors from the first and third partial evaporation are in the special column in a first condensation phase with high flow rate guided upwards in the range of 30 to 50 m / s on outer heat exchanger surfaces, above from the special column and also above the outer surfaces of the Heat exchanger supplied. The first condensation phase provides the energy for the double rectification described later. The draining flow-free condensate is added as a circulation amount to the first partial evaporation. In the outside Heat exchanger takes place the already mentioned second condensation phase of the steam on outer surfaces, the second partial evaporation on the inner surfaces of the Heat exchanger causes. The steam-condensate mixture is taken from the bottom of the heat exchanger withdrawn and totally condensed. This condensate is now at the head of the special Column abandoned on the inner surfaces of a first partial re-evaporation, in which the flow at a high steam speed of 30 to 50 m / s rectifying about the Phase equilibrium is evaporated out and the unevaporated Condensate as a flow-free second main run at the bottom of the first re-evaporation expires. The vapor from the first re-evaporation is condensed and on top abandoned the second partial re-evaporation on inner surfaces. In the second re-evaporation, rectifying, evaporates the flow enriched, is condensed and to a part that corresponds to the amount of light parts in the raw mixture and possibly newly formed lighter parts from the third partial evaporation, discharged and on the other hand the condensate from the second ondensationsphase supplied as a circulation amount.

The condensate resulting from the second re-evaporation below becomes also mixed with the condensate of the second condensation phase as a circulating quantity. The rectification on the inner surfaces takes place in countercurrent phase contact, whereby from the first inner area at an effective steam velocity of 30 to 50 m / s the flow is evaporated beyond the phase equilibrium and the second inner surface as the actual rectification stage - as a result of the circulation - serves.

The most advantageous pressure and speed ratios of the Steam in the first and second condensation phases and in the first and second Re-evaporation have become with PDal = PDa4 Pod5 400 Pa and VDa1 C V0a3 = VDa5 45 m / s exposed.

The pressure and speed conditions in the second partial evaporation of the raw mixture are preferably PgXa2 113 Pa and VDa2 30 m / s.

Those from the residual separation from the second falling film or thin film evaporator Possibly new light-sealing ankle caused by thermal rearrangements The condensate flows through the condensate from the outside of the Column arranged outer surfaces on the first inner surface in the column for separation of the first runnings and consequently do not lead to a reduction in the quality of the main distillates. the from the residual evaporation with the steam passing over high-boiling paint and ong. Impurities such as I3. unsaponifiable constituents, are attached to the exterior Areas with little rectification effect held back It corresponds to the essence of the invention if no Vorlaut parts are available or not removed should that then the condensates from the first partial evaporation and residual evaporation discharged outside the column after the heat exchanger as end products as well as the Vapors from the inner surface of the heat exchanger outside the column condensed separately and be discharged.

An advantageous procedure is that the crude product in a trickle heater with the heating medium drain from the falling film or thin film evaporator preheated to boiling temperature and at a pressure of 3990 to 13,300 Pa, preferably 5320 Pa, ontgast and dehydrateda The solution according to the invention has the advantage that 20 2t saves up to 30% energy compared to conventional methods, the apparatus Effort reduced by 50% and a high yield with very good quality too inferior input products is achieved.

According to the invention the object is achieved in that in a per se known column with outer and inner heat exchanger surfaces, preferably Rchrbündei, the inner surfaces on the head and on the bottom are separated into two by chambers so-called re-evaporation are divided and the outer surfaces with the jacket the column forms the condensation space of a so-called first condensation phase, which in the upper part via a product steam line with a conventional heat exchanger, the outer heat exchanger surfaces, preferably tube bundle, with the jacket Represents the condensation space of a so-called second condensation phase, and below via product steam lines with a so-called first and a so-called third Partial evaporation fung, each consisting of one or more Falling-film or thin-film evaporators are connected to the condensation chamber the column still has a condensate return line for the first partial evaporation. The evaporator or evaporators of the first partial evaporation is over on the liquid product side a liquid product line with the inner surfaces of the heat exchanger made in such a way represents the so-called second partial evaporation, and the evaporator or evaporators the third partial evaporation, so to speak, connected in series. The liquid product line are after the first evaporation device a floating reservoir, a conveying device and a regulating device interposed. Behind the regulator integrates a lockable short-circuit line, which leads to the evaporator of the third Partial evaporation leads. The raw product feed is advantageous with a preheater connected and the bottom of the evaporator device of the third partial evaporation has a discharge line for the residue.

At the top of the heat exchanger, i.e. the second partial evaporation connected a line leading to a total capacitor on the liquid side the discharge line for the first main run is connected.

There is also a total condenser at the bottom of the condensation chamber of the heat exchanger connected, which condensate side with the upper chamber of the first partial re-evaporation is connected. This adjustable condensate line is also available with the Condensate drain of the second re-evaporation and described with a second Discharge line connected for the flow and thus acts as a circulation line for the light fraction. An intermediate conveyor and floating template cause the media flow. In the event that there is no lead or none The flow is to be removed, a shut-off device is in front of the conveyor and a discharge line with a shut-off valve. The upper chamber of the first Re-evaporation is with the interposition of a total condenser with the upper one chamber the second re-evaporation is also a total condenser downstream, on the condensate side of which the aforementioned controllable discharge line is connected for the flow.

There is a discharge line in the lower chamber of the first re-evaporation connected for the second start-up.

On the float template, that of the raw product line after the first Partial evaporation is interposed, a vacuum line is connected, the vapors appropriate to the vapors lying between the column and the heat exchanger management leads. This vacuum line can also be a vacuum line for the trickle heater be connected.

The condensate side of all total capacitors is with a vacuum line connected to which the float template between the heat exchanger and the first re-evaporation lying condensate line is connected.

Between the evaporator device of the first partial evaporation and A heating medium circuit line can be connected to the trickle heater.

The solution according to the invention has the advantage that 20% to 30% energy saved compared to conventional methods, the expenditure on equipment reduced by 50% and a high yield with more good quality even with inferior input products is achieved.

The 8 m high exchange surface required in known processes reduced to 3 m.

Embodiments The method and apparatus are as follows explained in more detail. The drawings show: FIG. 1 a schematic representation of FIG Apparatus for separating multicomponent mixtures FIG. 2 is a schematic representation the flow of substances in the separation of a multicomponent mixture of main stream and residue 3 shows a schematic representation of the material flows during the separation of a multicomponent mixture in lead, main run and backlog.

Example 1 (see Fig. 3) From a drained and degassed fatty acids with a free fatty acid content of 96% should be a Pre-run portion of 2% and a main run of 94% are separated. The raw mix F11 is fed to a trickle heater 1, which is connected to the heating medium drain heated from the thin film evaporator 2, and continues into the thin film evaporator 2, where about 50% of the feed product is evaporated at about 400 Pa. The exiting Steam Da1 flows with an effective steam velocity of 45 rnZs on the outer Area 3, which has a height of 3 m, in column I at 400 Pa upwards and becomes on top of the outer surface of the heat exchanger disposed outside of the column 1 4 supplied. The portion x1 not evaporated in the thin film evaporator 2 becomes the inner surface, of the heat exchanger 4, which is under a pressure of 133 Pa, supplied. As a result of the heat exchange in the apparatus 4, they evaporate at an effective steam speed from 30 m / s about 35%, based on the raw mixture feed rate. This steam becomes Da2 condensed in the condenser 5 and removed as the finished product F12 (first main run).

The portion that has not evaporated from the inner surface of the heat exchanger 4 x, becomes a second falling film evaporator located on the lower part of the KO10nne 1 6 supplied. The portion of about 4 hours that has not evaporated here, based on the raw mixture feed quantity, is discharged as residue F13. The evaporated in the thin film evaporator 6 Follow-up Da3 with a narrow of about 11% based on the raw mixture feed quantity, flows together with the steam Da1 on the outer surface 3 in the column 1 and is fed to the outer surface in the heat exchanger 4 above the column I. Of the on the outer surface of the heat exchanger 4 not yet condensed steam Da1, Da, is condensed in the condenser 7 and this entire condensate 4 on the first re-evaporation on inner surfaces 8, which acts as a pure output column, and in it a pressure of 400 Pa is maintained. Due to the temperature difference on the outer area 3 and the inner surface 8, there is partial evaporation Da4 of about 20% of the abandoned Quantity F14.

This vapor Da4 is condensed in the condenser 9 and transferred to a second Re-evaporation on inner surfaces 10, which mainly acts as an amplifier column, abandoned Here about 10% evaporate. The amount Da, we <1 is condensed in the condenser 11 and the condensate F1 is partially up to approx. Taken as a highly enriched preliminary product F16 and partly as a light circulating quantity F17 mixed with the condensate F14.

That from the second inner surface 10 has not evaporated and partially F18, which is reduced to about 10% of the flow components, is also included in the condensates F14 and F17 mixed in and now together on the first inner surface 8 of the column 1 abandoned.

That which has not evaporated from the first inner surface 8 and of first run components Free portion F19 of around 59% occurs as a finished product (2nd main run).

Due to the amount of liquid applied to the inner surfaces 8 and 10 there is partial condensation of the vapors Da1 + Da3 on the outer surfaces of about 30%, based on the mixed feed quantity. This condensate F110 is called the circulating amount mixed with the raw mixture and the thin-film evaporator 2 for re-evaporation given up. The energy consumption based on a one-time evaporation is in this case about 95%.

When processing inferior raw products with a free fatty acid content from about 59% end products of about F12 = 23, F16 = 2%, 1.3 G 41 °, F19 = 34%, based on the amount of mixed feed. The energy consumption, related for a single evaporation, in this case is about 107%.

Example 2 (see FIG. 2) From a dehydrated and degassed split fatty acid with free fatty acid content = 96%, a main run of 96 8 should be separated.

After the raw mixture F11 has been heated to the boiling point in the trickle heater 1, about 62% of the feed product is evaporated at 400 Pa in the thin-film evaporator 2. This steam Da1 flows at an effective steam speed of 30 m / s im Column space I and is above the column a heat exchanger arranged outside 4 supplied to the outer surfaces. The non-evaporated portion x1 from the fill film or Dünnschichtver evaporator 2 is the inner surfaces, which are under a pressure of about 133 Pa are supplied to the heat exchanger 4.

Due to the temperature gradient on the outer and inner surfaces Im Heat exchanger 4 results in partial evaporation Da2 of that which is given up on the inner surfaces Liquid quantities. This vapor condenses in the condenser 5 and falls as a finished product F12 on. The portion x2 not evaporated in the heat exchanger 4 is one below the Column arranged second falling film or thin film evaporator 6 supplied. In this, about 11, based on the amount of mixture inflow, evaporate. The steam DQ, comes together with Dal to the outer surfaces of the heat exchanger 4 is im Condenser 7 is condensed and discharged as a finished product F1.

The portion of about 4 not evaporated in the thin film evaporator 6 % F13 (residue) is also obtained as the end product.

The energy requirement, based on a one-time evaporation, is about 73 23.

Are products with a free proportion of fatty acids of about 59 % processed, the quantities are roughly: Da1 = 38%, Da2 = F12 = 15%, Da3 = 6%, Da1 Da3 = F19 = 44 and F13 (coarseness) = 4% here energy requirement, based on a single evaporation is about &> 5 35%.

Example 3 (Fig. 1) II of the column I shown in Fig. 1 are 3 in long tubes with an outer tube spacing of preferably 20 cm above and below in one each to the column boss sealed bottom 12, 13 welded in and form the outer surfaces 3 for the first condensation phase and the inner ones Areas 8,10 for the first and second t * 9-'iew derverdmapfung. Are at the top of the column the tube is provided with the usual liquid distributors and that as a stripping column acting tubes 8 through the chamber 14 of the acting as an amplifier column tubes 10 separated. The same chambering 15 takes place in the lower part of the column.

To a trickle heater 1, which with the heating medium blue? from the falling film thin film evaporator 2 is heated via the line 16, the Rchproduktzufuhr takes place by means of a line 17 and then through line 18 to falling film thin film evaporator 2, where the first partial evaporation takes place. The evaporator of the first partial evaporation The condensate of the outer surfaces 3 also flows via the return line 59 as Circulation volume to.

The product that has not evaporated in the falling film Dünschichtver arrives through the line 25 to the float template 26, which via the vacuum line 27 as also via the vacuum line 25 of the trickle heater 1 with vacuum from the steam line 20 is applied, the pump 30 sucks out the crude product via the line 29 the float template and presses it regulated by control valve 31 on the inner Areas of the heat exchanger for the second partial evaporation. The line 32 is with Shut-off valves 33, 34 provided so that a liquid supply to the inner Surfaces 35 of the heat exchanger 4 as well as on the falling-film thin-film evaporator 6 is guaranteed. Below the heat exchanger 4, a line 39 leads to the falling film or thin film evaporator 6 via which the remaining crude product for the third partial evaporation got. The residue flows off via the discharge line 40.

The heat exchanger 4 is above a vapor line 36 to the condenser 5, in which the steam from the first main run condenses, downstream via the Discharge line 38, in which the vacuum line 37 is also incorporated, is the Finished product deducted. The evaporated portion from the third partial evaporation passes through the steam line 41 together with the steam from the first partial evaporation from the line 19 after the first condensation phase on the outer surfaces 3 the column 1 to the steam line 20 and further to the outer surfaces 21 of the heat exchanger 4 to the second phase of condensation and then via line 22 to the condenser 7. The condensate line 24 from the partial condenser 7 is a float reservoir 42 downstream, to which the vacuum line 43 is also connected, and to the vacuum line 23 leads. Through the shut-off valves 44, 45 the product can optionally - if no Flow is removed - discharged or - if the flow is discharged - to Pump 46 are discharged. The product is fed to the line 48 inner surfaces 8 of the first re-evaporation, so the stripping column. The ascending one Product vapor is fed through line 49 to the condenser 9, which also the vacuum line 50 connects.

The condensate is by means of line 51 on the inner surfaces 10, which act as an amplifier column, given up for the second re-evaporation.

The non-evaporated portion is used as the second main run through the line 52 discharged.

The product vapor emerging from the intensifier column of the inner surfaces 10 is enriched flow and passes through line 53 to condenser 11, to which the vacuum line 54 and the finished product line 55 are also connected. In the line 55 there is a control valve 56 above which a connecting line 57 leads to the product line 24 for the slight circulation volume.

The product line 58 from the drain also binds into this line 24 of the amplifier column 10. The entire system is evacuated by the Line 60. The pressure difference required to operate the system is determined by a corresponding Line dimensions of lines 49, 53, 20 for the higher pressure ranges and through lines 22 and condenser 7 for the low pressure range without additional control devices guaranteed. The application of heat to the thin-film falling film evaporator take place through the inlet lines 61, 62 and the outlet lines 16j 63.

L e r s e i t e

Claims (11)

P a t e n t a n s p r ü c h 1. Process for the separation of thermal sensitive multicomponent mixtures in a vacuum, after their degassing and dewatering by distillation, evaporation and condensation, characterized in that the Multi-substance mixture at a pressure of 300 - 500 Pa in one containing the flow Main run and a main run containing the residue is separated, which the Main run containing residue then rectifying at 100 - 200 Pa in a 1 a first main run representing an end product and in a subsequent run? separated and this after-run is evaporated down to the separable residue, the resulting Nachlaufdarnpf together with the flow containing main steam of the first Evaporation in countercurrent at a rate of 30 to 50 n / s with forward flow containing condensates are contacted at 300 - 500 Pa, with simultaneous Rectification a forerun that evaporates beyond phase equilibrium, which does not evaporated portion is obtained as a second main run representing an end product, containing the vapors that have evaporated beyond phase equilibrium condensed, circulated and re-evaporated at 100-200 Pa and subsequently as highly concentrated first runnings are separated. 2. Device for separating thermally sensitive multicomponent mixtures with little, narrow, low-boiling and high-boiling impurities in their column space Heat exchange devices are accommodated, characterized in that the heat exchange devices (8, 10) are pipes with an outer pipe spacing of 10 to 30 cm, preferably 20 cm, the pipes a first condensation and relaxation room with return line (59) form, the up and down through usual floors (12,13) of a steam room and a space for liquid product is limited and the inner surfaces (8,0) through Chamber in the steam space (14) and in the liquid product room (15) are separated so that the first inner surfaces (8) have a first low evaporation or form a stripping column, which in the lower part is connected to a finished product line (52) is provided and in the upper part with a damping line (49) with subsequent Condenser (9) and product line (51) on the inner surfaces (10), which have a second Form re-evaporation or booster column (10) opens out and the booster column (10) in the lower part a connecting line (58) to a condensate line (24) and in the upper part a capacitor (11) is connected via a damping line (53) A finished product line (55) is integrated into the condensate side, which is a control valve (56), in front of which a connecting element (57) leads to the condensate line (24) and evaporation devices on both sides at the lower I column space (1), preferably Thin-film or falling-film evaporators (2,6) are arranged, their damping lines (19,41) open into the first condensation space (3) at the bottom and at the top of the first condensation space (3) via a damping casing (20), the outer surfaces (21) of a conventional heat exchanger (4) is also connected as a second condensation space at the top, the one at the bottom conventional total capacitor (7) is arranged downstream via line (22), the condensate line of which (24) with the interposition of floating template (42), conveyor (46) and Control device (47) on top of the first re-evaporation leads and the inner ones Areas (35) via a line (39) with the evaporator device (6) to one line for the residue is downstream and in the upper part on the one hand via a damping line (36) with a capacitor (s) to which a finished product line (38) is connected and on the other hand via the raw product lines (32,25), which float feed (26) Pump (30) and control device (31) are interposed, with the falling-film thin-film evaporator (2) the first partial evaporation in the lower part is connected and the condensers (9, 11, 5, 7) separate vacuum lines 3. The method according to claim 1, characterized in that in the distillation of a multicomponent mixture without Lead portions after the extraction of the first main sound and the residue remaining vapors are fully condensed as the second main run. 4. The method according to claims 1 and 3, characterized in that that the main run containing the residue of the first evaporation immediately one Residual evaporation at 300 to 500 Pa is subjected, as a result of which the residue is separated. 5. Vorr il rectification according to claim 2, characterized in that a Short-circuit line (29) with shut-off valve (34) between the product line (32) with shut-off valve (33) upstream and the product line (39) downstream of the heat exchanger (4) lies. 6. Device according to claims 2 and 5, characterized in that that the raw mixture in a trickle heater (1), which is made with the Heiznsedienvorgang the case film or thin film evaporator (2) is heated to boiling temperature is preheated and connected to this a vacuum line 628) to the steam line (20) is, 7. Device according to claims 2.5 and 6, characterized in that a or several falling film or thin film evaporators (2,6) in the lower part of the column are arranged one below the other. 8. Device according to claims 2,5,6 and 7, characterized in that that pressure-retaining damping lines (49,53,36,22) and capacitors (9,11,5,7) are installed are. 9. Vorscichtuny according to claims 2,5,6,7 and 8, characterized in that the system is evacuated with a main line (50), this a vapor wash with a downstream recipient is connected. 10. Device according to claims 2,5,6,7,8 and 9, characterized in that the finished product lines (38,52) and / or the finished product lines (4, 52) or the finished product lines (38, 48, 52) lead into a collecting line. 11. Device according to claims 2.5.6.7.8.9 and 10, characterized in that the trickle heater (1) via the vacuum line (28) to a separate Recipient is connected.