NO151379B - PROCEDURE FOR THE MANUFACTURING OF INSULATING CURTAIN CONSTRUCTION, AND CURTAIN CONSTRUCTIONS MADE IN ACCORDANCE WITH THE PROCEDURE - Google Patents

Abstract

Method for manufacturing insulating curtain construction, as well as curtain constructions, manufactured according to the method.

Description

Method and apparatus for fractionating a liquid mixture of organic substances.

The present invention relates to an improved method and apparatus for the distillation and rectification of high-boiling and heat-sensitive material and, in particular, to a method and an apparatus for the fractional distillation of such material on

in such a way that any thermal decomposition, polymerization of, or other significant thermal damage to the obtained distillates or residues is prevented.

In particular, the present invention relates to an improved method and an apparatus for producing rosin from crude tall oil, so that the rosin is essentially free of fatty acids and unsaponifiable compounds, and while fatty acids are essentially free of rosin and unsaponifiable compounds. The invention also relates to an improved method and an apparatus for the production of a palmitic acid fraction from raw cotton seed fatty acids, which fraction essentially lacks olefinic

isic fatty acids and unsaponifiable matter and an olefinic fatty acid fraction, which mainly lacks palmitic acid and unsaponifiable components. It also relates to an apparatus which is particularly intended for use under high vacuum for the rectification of fatty acid-containing material for the production of fatty acids, which are essentially free from unsaponifiable materials, and an essentially unpolymerized residual fraction.

In order to show the applicability of and the advantages of the method and the apparatus to which the present invention relates, the methods for producing rosin and fatty acids from crude tallow oil and the invention's advantages over previous methods are dealt with below. This treatment is provided for information purposes and the person skilled in the art will easily realize that the same advantages can be transferred to the rectification of other fatty acid-containing materials and the fractional distillation of other heat-sensitive and high-boiling materials.

Tall oil in this form has a limited applicability. Dependent

of its origin, the tall oil contains 35-65% resin acids, 25-6o% fatty acids and 3-3o% unsaponifiable compounds. In a method for acid refining, part of the unsaponifiable compounds can be removed and the recovered fraction's color and odor in

is greatly improved, which results in a more valuable product, which is generally marketed as refined tallow oil. In recent years, however, the main industrial interest in tallow oil has been its value as a raw material for the manufacture of rosin and fatty acids. Fractional distillation is almost universally used commercially to separate tallow oil into its individual components. Because the material is sensitive to heat, it must be distilled at a temperature well below its boiling point at atmospheric pressure. It is therefore used commercially

generally vacuum distillation. As the boiling points of the individual components are close, however, a high temperature with several bottoms is required

ner supplied (or equivalent), conventional rectification columns for carrying out the separation. In operation, such columns have a pressure drop from the bottom to the top corresponding to 4o or 5o mm Hg, so that the pressure at the bottom of the column and in the distillation flask or reboiler will be 4o or 5o mm Hg, even if a very high vacuum is maintained at the top of the column, (eg an absolute pressure of 1 mm Hg). In order to avoid a resulting increase in the boiling point, it is usually practiced to feed water vapor into the flask, which produces the necessary lowering of the boiling points of the tall oil components according to the law of partial pressure, as 0.4-2 kg of water vapor is constantly fed in for every kg of tall oil added. This addition of water vapor greatly increases the costs of the device and its operation, e.g. is the required heat for evaporation of o.454 kg of fatty acid approx. 3o kcal, while, on the other hand, the evaporation of water requires approx. 25o kcal/0.454 kg. Thus, the addition of water vapor increases the heat requirement for distillation 3-15 times. Furthermore, the injected water vapor must be taken care of in the vacuum-generating system, whereby its size and operating costs increase to a great extent. With regard to the size and price of the distillation apparatus, the regulating factor is more the distillation vapor volume than the weight, and the larger this volume becomes, the larger the distillation apparatus must be. The volume of 1 kg of water vapor is approx. 15 times the volume of 1 kg of fatty acid or rosin vapor at any given pressure. It thus appears that the addition of steam greatly increases the volume of steam and consequently the size and price of the appliance. As the size and complexity of a system under vacuum increases, it becomes more and more difficult to construct and maintain such a system. It is thus realized that a method for anhydrous rectification has great potential advantages.

In the past, however, attempts at vacuum rectification of tallow oil in an anhydrous state have not been particularly successful or commercially appealing. Because of the difficulty in separating the components, conventional rectification columns are required of such a height that the pressure drop through the column precludes maintaining sufficient vacuum throughout the system to produce the necessary boiling point reduction. In the past, attempts to avoid this difficulty quickly resulted in complicated and unmanageable equipment with colossal investment costs. A simple, compact apparatus which is relatively cheap to construct, which is flexible in operation and easy to maintain and yet is capable of fractionally distilling tallow oil in the anhydrous state so that essentially complete separation of the fatty acids, resin acids and the unsaponifiables is achieved constituents, would be very beneficial for the industry, and such an apparatus is to the very highest degree desirable.

The present invention generally aims to provide a simple method and a relatively cheap, compact apparatus, which is flexible and easy to fit and easy to maintain, as this apparatus has a very low pressure drop between any two points within the apparatus, so that the maximum pressure in each area exposed to high temperatures can be maintained at an equal value which is of the order of 5 mm Hg or less, this apparatus also having sufficient heat exchange surfaces which are arranged in such a way as to produce sufficient successive or alternating evaporation and condensation to enable it here described procedure, and by means of which one

can achieve the degree of fractionation and rectification necessary for each desired degree of separation of two fractions with close boiling points, e.g. the resin acid component and the fatty acid component in tallow oil.

The invention also aims to provide a continuous flask still, in which the liquid in the flask, when a binary or polar mixture is distilled, never reaches a uniform equilibrium composition as in ordinary or conventional flask stills. According to the present invention, the flask is an elongated, essentially horizontal vessel, in which little or no mixing of the flask's liquid takes place in the longitudinal direction of the vessel. I.e. during the operation of the apparatus, the composition of the flask's liquid will vary from one end of the horizontal elongated vessel to the other depending on the differential distillation that occurs when the remaining liquid is made to flow from the point of inflow to the point of outflow. The composition of the remaining liquid at each point is a function of the growth of the liquid that evaporates per unit length of the horizontal elongated still, and can be determined from the isolable liquid-vapor composition curves that can be obtained from Raoul's law. During planning and operation, the composition of the remaining liquid at the point of outflow from the vessel can be made to vary over a certain range regardless of the combined composition of the distillate vapors and regardless of the ratio between the amount of distillate and the amount of residue removed. While, on the other hand, up to now with continuous distillation apparatus and methods, all the liquid in the flask or kettle inevitably attains a uniform, constant composition under equilibrium conditions and is essentially in equilibrium with the vapor leaving the surface, and consequently the extracted residue has the same composition as the residue in the flask, and its composition is directly proportional to that of the distillate vapors according to Raoult's law.

The invention further aims to provide a continuous flask distillation apparatus which consists of an elongated, essentially horizontal heat exchanger and a vapor space which is enclosed by an elongated mantle connected to the horizontal heat exchanger, the mantle providing condensation surfaces for the vapors rising from the elongated horizontal heat exchanger. During the operation of the apparatus, the compositions of the vapors will vary from one end of the horizontal, elongated vessel to the other, continuous differential condensation is produced as the vapors are partially condensed,

and the condensed portion returns to the flat-bottomed heat exchanger for further differential evaporation, whereby the desired degree of rectification is achieved by continuous repetition of evaporation and condensation.

The invention also aims to produce an apparatus in which rectification is carried out by simultaneous continuous differential distillation and differential condensation without filling chambers or bells in the vapor space, and which thus produces separation of the component volatile compounds to the desired degree of purity with a very small pressure difference in the apparatus.

The invention further aims to produce an apparatus in which the higher-boiling component is finally purified to the desired purity in an elongated, flat-bottomed, differential evaporator-condenser, whereby the high-boiling component withdrawn as a liquid and the high-boiling component's purity is varied as desired, as the extracted liquid is never in equilibrium with the combined vapors, therefore its composition is independent of the vapors above it and the amount of liquid to the amount of vapors, which enables a higher purity of the high-boiling component than was previously possible.

The invention also aims to produce a mainly horizontal, flat-bottomed, continuous, differential evaporator with upper surfaces that produce continuous, differential condensation, with steam outlet for the rectified, low-boiling steam fraction and the rectified, high-boiling steam fraction and residual outlet for the non- volatile residue.

The invention also aims to produce an elongated, horizontal, flat-bottomed, continuous, differential evaporator and differential condenser, which can be used with one or more columns provided with a small filling, columns provided with glass beads or condensers with falling film, since the pressure drop through the apparatus is such that the boiling temperature is lower than the decomposition temperature of the mixture.

The invention further aims to produce an apparatus with two zones, where one zone produces separation of the fractions by rectification, the other zone ends the separation by simple or differential distillation. Zone 1 is a short rectification zone, preferably of the filled type, so that there is a minimal pressure drop in it. The zone 2 can be a flat-bottomed heat exchanger, on which the material is lined as a film and purified by simple distillation or differential distillation. Zone 1 and zone 2 are in a certain relationship to each other, i.e. that the construction of zone 2 is determined by the degree of rectification achieved in zone 1.

The present invention also intends to produce an apparatus which is a continuous flask distillation apparatus with a rectification tower for its upper section, preferably of the packed type, for rectification of the lower boiling fraction to the desired degree of purity and with a horizontal, flat-bottomed heat exchanger for its lower section or flask and which, by differential distillation of a film of the higher boiling fraction emitted from the upper section, purifies the higher boiling fraction to the desired degree of purity.

The invention also relates to an apparatus consisting of several continuous flask distillation apparatuses. The number of stills is a function of the desired purity of the lower boiling fraction and the desired pressure to be maintained in the flask or horizontal sections of the apparatus.

The invention also aims to produce an apparatus in which the saturated material, which is to be fractionated, is first driven off the desired volatile components on a horizontal heat exchanger equipped with a flat bottom under high vacuum with a very short residence time for the residual fraction in the heat exchanger, of the order of magnitude 3 minutes, so that minimal polymerization of or minimal thermal damage to the residual fraction occurs.

The invention also intends, by stripping, to make the crude tall oil more free of its fatty acids and its resin acids than has hitherto been common and to produce a residual material which is essentially free of rosin, fatty acids and polymerized material, so that further separation of the residue into valuable compounds are not complicated by the presence of significant amounts of fatty acids, rosin and polymerized material.

The invention further intends to produce an apparatus in which, after stripping off rosin, fatty acids and some unsaponifiable

compounds in vapor form from the crude tall oil, the vapors are sent into a rectification zone where the lower-boiling, unsaponifiable compounds that have color and odor are removed as distillate and the return stream is sent through a rectification zone on a horizontal, flat-bottomed heat exchanger, where the differential is distilled and a small, colored rosin fraction is removed. The main part of the product immediately condenses below the lower boiling colored fraction.

The invention further relates to providing an apparatus in which the lower-boiling, colored and odor-provided fraction and the higher-boiling, colored fraction and the rest of crude tall oil are removed, before the fatty acid-rosin mixture is sent to the sections for final rectification and differential distillation for separation into fatty acids with the desired degree of purity and into resin acids with the desired degree of purity and with a desired degree of light color. E.g. is it common in commercial operations to redistill the fatty acid fraction in order to obtain a product with great color lightness and a high acid number, which is a measure of its purity, since the redistillation of the rosin to remove the colored fraction and increase its purity is not a rational approach. The apparatus and the method according to the invention remove the low-boiling, color- and odor-provided fractions and the high-boiling, color-provided fractions from the main mass of vapor before the mixture is condensed. The evaporation of the condensed mixture of rosin and fatty acid and rectification and the differential distillation lead to a rosin product of high purity and lighter colour. It is both detailed and advantageous with the apparatus according to the invention to produce a rosin product that is single, double, triple, etc. distilled, whereby the rosin end product is mainly free of unsaponifiable compounds and has a lighter color than that commercially classified in the trade.

The invention also aims to produce a distillation apparatus, where the condenser produces separation by partial condensation and at the same time produces reflux to the horizontal differential-evaporator-differential-condenser to maintain the desired film layer thickness and the desired composition for the film in the flask.

The invention also intends to produce an apparatus which consists of an elongated, horizontal evaporator with upper surfaces, which produces continuous differential condensation, whereby the ratio of differential condensation is varied so that as the vapors are sent in countercurrent upwards towards the feed, the condensation becomes smaller and smaller, whereby it is achieved without the desired

quantity of steam with the desired purity.

The invention also aims to provide an apparatus which consists of an elongated horizontal evaporator with upper surfaces which cause differential condensation, and in which apparatus the heating medium is a liquid, e.g. Dowtherm, and the heating liquid is made to flow countercurrently to the film in the evaporator, which causes the heating liquid to differentially heat the film in the flask.

The invention also provides an apparatus in which distillation methods of (1) partial condensation, (2) rectification, (3) differential distillation are combined as advantageously as possible in order to obtain a compact apparatus, which is simple in construction and economical to carry out , and which nevertheless has the correct rectification capacity to produce a separation between two fractions with close boiling points. An apparatus which is constructed in such a way that the pressure drop through it is such that the boiling point of the material to be fractionated is lower than its decomposition temperature at the greatest pressure within the apparatus.

The invention also aims to produce an apparatus in which the residence time on all heat exchange surfaces is of the order of magnitude 1-3 minutes rather than 15-60 minutes, and evaporation takes place from films flowing along planar heat exchange surfaces.

The invention therefore aims to produce a method and an apparatus which works under water-free conditions and at a lower temperature than hitherto commercially used apparatus, as the corrosion which originates from moisture at high temperature in the presence of acidic materials is reduced.

The invention further relates to producing a method and

a device, in which it is not necessary to blow in superheated steam, whereby the erosion effect is excluded.

The invention also aims to produce arrangements of devices and methods for fractionating different components of starting material of the type described above into a significant number of different component fractions, each of these fractions being taken out individually at a special point or place in the device or during the processing , where the concentration of a selected component is brought to a maximum in the particular fraction of several components.

The invention further aims to produce devices by apparatus and method for fractionating different components of the starting material of the described kind into a significant number of different component fractions in several individual units for differential evaporation and condensation, the smallest parts of the individual units being essentially identical for the modular device and their mutual relationship with a view to both liquid and vapor flow through the devices through the apparatus.

The invention further aims to produce devices by apparatus and method for fractionating starting material of the kind described here into several different component fractions in a processing stage, whereby each fraction has a separate concentration of a specially selected component in it, and then easy re-introduction of such fractions in another processing stage for further rectification and fractionation of individual components in such multi-component fractions.

The invention also relates to producing devices by apparatus and method for fractionating starting material of the kind described here into several different multi-component fractions in one stage of the processing and then re-introducing at least some of such fractions in a subsequent processing stage for rectification and fractionation of components, such fractions is introduced in the subsequent processing step at different points according to the special component construction in the individual component fractions.

The aforementioned purposes and other purposes and advantages of the invention will be clear to those skilled in the art from the following description and drawings.

In order to get a better picture of the method and the apparatus according to the invention, the preferred embodiment of the invention will first be elucidated and described in detail and then the method steps will be described taking into account the particular apparatus described, although it is naturally considered that the method can be carried out in a device other than that specifically described and discussed. Reference is made to the attached drawings, where

fig. 1 schematically shows the preferred embodiment of the apparatus according to the invention, and which also shows how the method according to the invention can be carried out,

fig. 2 shows one end of one in fig. 1 shown, differential evaporator-condenser lo,

fig. 3 shows from the side in cross-section the one in fig. 1 shown, differential evaporator-condenser lo,

fig. 4 shows from the side. in cross section one in fig. 1 shown differential evaporator-condenser 11,

fig. 5 schematically shows a flow chart that illustrates one form of the device at the apparatus and processing during adaptation of the present invention when treating tallow oil for its fractionation into several rosin, fatty acid fractions and other intermediate fractions or other combined or rectified component fractions, and

fig. 6 shows somewhat schematically a to fig. 1 corresponding form of the device at the apparatus and rectification components under adaptation of the present invention, e.g. in use in a device for processing, which is shown in fig. 5.

The same reference designations are used in the different drawings to indicate the same kind of parts.

With reference to fig. 1 showing two differential evaporator condensers 10 and 11, which are connected to each other by a condenser 12 and a steam line 13 and connected to a common vacuum header 14 by means of steam lines 15, 16 and condensers 17, 18 and 19 and lines 2o and 21 for non-condensable vapors. A vacuum can be created in the vacuum collecting rudder 14 with any suitable evacuating means 22, e.g. a vacuum pump, which works over a line 23.

Reference is now made to fig. 2 and 3 for further details. The differential evaporator-condenser lo is an elongated, horizontal vessel whose bottom is a long, flat, rectangular heating plate 24, which contains several parallel hollow channels 25,

which runs lengthwise through the plate between rudders 26 at each end which are connected to collection rudders 27, for circulation of a heating medium with a desired temperature through the plate. The walls and upper part of the differential evaporator-condenser 10 consist of a sheet metal shell, part of which is enclosed in a jacket 28 with inlet 29 and outlet 30, by means of which a coolant with a desired temperature can be circulated through the jacket, whereby this jacket part part of the shell can be used as a condenser surface 31. The length and area of this condenser surface is a matter of calculation. In this embodiment, this extends from the outermost upstream long setter approx. 2/3 of the vessel's length, whereby the area of the condenser surface gradually changes from the upstream end to the downstream end. Remaining external surfaces 32 are insulated to prevent condensation and heat loss. A feed inlet 33 is provided, which enables fed material to be introduced directly onto the heating plate at a point located 1/3 (more or less) of the distance from the steam outlet 15 to the downstream end of the condenser surface. An outlet 34 for non-evaporated material is arranged at the extreme opposite end in the downstream direction from the inlet of the feed. The upper part of the Utlbpsrbret sticks into the tub approx. 1 mm above the upper level of the heating plate. At a short distance above the plate, elongated holders 35 are arranged to hold a countercurrent separator 36 which may or may not be necessary, depending on the nature of the raw material. A removable manhole 37 is arranged at the end for inspection or cleaning of the vessel.

Reference is now made to fig. 4 for further details. A differential evaporator-condenser 11 is an elongated horizontal vessel, the bottom of which is a long, flat rectangular heating plate 38 containing several parallel hollow channels 39, which run longitudinally through the plate to paddles 4o at each end and then to a manifold 41 for circulation of heating medium with a desired temperature through the plate. The walls and upper part of the .

a differential evaporator 11 consists of a shell of metal plates, part of which is enclosed in a shell 42 with an inlet 43 and an outlet 44, through which the refrigerant at a desired temperature can be circulated through the shell, whereby this sheathed part of the shell is used as a condenser surface 45. This condenser surface extends from the upstream end of the vessel to a point approx. 3/4 down the length of the tub. The vessel's remaining external surfaces 46 are insulated. A steam inlet 13 is inserted into the vessel through its upper part after a distance of approx. 1/3 of the vessel's length from the downstream end. An outlet 47 for non-evaporated material is arranged at the outermost downstream opposite to the steam outlet port 16. The upper part of the outlet 47 protrudes approx. 1 mm above the upper level of the heating plate.

The condensers 12, 17, 18 and 19 may be of any conventional construction as long as each condenser is of a size and construction which precludes any significant pressure drop through it.

In the following, a description of the method to which the present invention relates is given together with and in connection with a description of the working process for the previously described embodiment of the device. The material to be processed, e.g. raw tallow oil is fed in via a rudder 48 to a vacuum user 49 which can be of conventional construction and have a high vacuum maintained by means of an evacuation system 5o. In the tuber 49, essentially all the water and much of the non-condensable materials are removed. The resulting dried and deaerated raw material is made to flow through a pipe 51 and a pump 52 to a bleaching tank 53 which may be of conventional construction and have suitable means for heating and conversion. Here, the raw material is treated with a suitable bleaching agent. The bleached crude is then sent by a pump 54 through a rudder 55 and a filter 56, which may be of conventional construction, and then over a line 57 to a feed storage tank 58. The crude tall oil is then fed by a pump 59 through a rudder 6o to a feed preheater 61.

In this preheater, the raw material can be heated to a desired temperature, but for processing tall oil it is preferred to heat the tall oil to a slightly lower temperature than the temperature maintained in a differential evaporator-condenser. From the preheater, the feed stream is fed by means of a rudder 62 with a predetermined quantity per time unit into the differential evaporator-condenser lo and is emptied onto the heating plate. The exact emptying point is a matter of calculation and depends on the nature of the material fed and the degree of fractionation of the desired components. For crude tallow oil, where maximum fractionation is desired, the optimal point for inflow in the described embodiment has proven to be at a distance of approx. 1/3 L downstream from the upstream end (where L is the vessel's total length).

Immediately, the feed spreads on the heating plate in a film with approx. 1 mm's layer thickness, which is determined by the level of the liquid outlet tube 34, and begins to flow downwards towards the outlet.

Because the feed is close to the inflow vaporization temperature, vaporization begins almost immediately and is maintained at a steady rate as the film continues to flow down. For calculations, the input quantity is regulated per unit of time and the temperature of the plate so that only a small part of the feed is evaporated for each unit of length of the plate over which the feed is sent. The plate's length and total area are calculated so that the total desired evaporation is achieved. At each successive point in the downstream direction, the distillate vapors and the liquid stream become continuously richer in high-boiling components as a result of differential distillations at the points in the forward direction, and conversely at each successive point in the upstream direction, the distillate vapors and the liquid stream continuously become poorer in high-boiling components.

The condenser surface arranged on the upstream part of the differential evaporator condenser works to further increase this concentration of components in the following way. Steam formed within this area is prone to flow upwards towards the upstream steam outlet 15, and because it hits the condenser surface it is differentially condensed, whereby the condensate falls back onto the plate in the upstream direction from the point of original evaporation, and the treatment is repeated again. The condenser's area and temperature can be regulated to achieve the desired quantity per time unit condensation, which in each case must be less than the plate's evaporation capacity. In the illustrated case, the amount of condensate is maintained per time unit preferably at approx. 1/2 of the evaporation quantity per time unit at the downstream end of the condenser and changes slowly to approx. l/lo of the amount of evaporation per time unit near the upstream end of the capacitor. Under such conditions, essentially all of the vapors formed on the plate below the condenser flow towards the upstream outlet 15 for low-boiling steam, and the vapors formed under the insulated part flow to the downstream outlet 13 for high-boiling vapours.

With these simultaneous, complementary methods for differential evaporation and differential condensation, a high degree of fractionation of the feed's components is achieved. E.g. when processing an average crude tallow oil containing 48% rosin, under the conditions and steps of the method described above, approx. 40% by weight of the feed into the steam line 15 as fatty acid containing at most 1-2% rosin, something over 40% is sent into the steam line 13 as rosin vapor containing approx. 15% fatty acids, while less than 20% is sent out through the liquid outlet 34 which is essentially free of fatty acids or products of thermal decomposition. The fatty acid vapors that flow into the condenser 17 are condensed with the exception of a small fraction that contains most of the substances endowed with color and smell, which, when they have a lower boiling point, are sent to the condenser 18 where they are condensed, whereby the temperatures of the two condensers is adapted in such a way that the desired condensation ratio can be achieved in each of them. The condensates are taken out through pipes 63 and 65.

If so 6nsk.es, e.g. when a raw material with a higher rosin content is processed, the drain valve in the condenser outlet tube 65 can be set so that part of the condenser 17 condensate can be sent back to the differential evaporator-condenser lo, whereby the fractionation can be improved by further differential evaporation-condensation effects and the desired amount liquid can be produced so that the upstream film with the desired layer flow and composition can be maintained. The steam, which contains approx. 85% rosin and which is sent out through the steam outlet 13, flows into the condenser 12 which operates at a regulated temperature in such a way that partial condensation of lo-2o% of the entering steam is achieved, whereby the condensate is approx. 95% rosin content and it is taken out. It has been shown that the colored substances in rosin can be concentrated and removed in this way in the higher boiling component. Ds vapors sent through the condenser 12 are fed by means of the steam pipe 13 to the upper part of the differential evaporator condenser 11, where they flow towards the steam outlet 16, while they are sent along the condenser surface 45 and differentially condensed on this.

The condensate falls to the heating plate and flows towards the liquid outlet 47, and the procedures for repeated, differential evaporation and differential condensation proceed as previously described. All vapors enter the vapor outlet 16 and are sent into the condenser 19, where they are condensed and the condensate is taken out through a line 67, a valve 66 being set so that part of the condensate is sent back through the vapor line 16 to the differential evaporator condenser so that the fractionation must be increased and the film must be maintained. The liquid film on the plate thus becomes more and more rich in the high-boiling component (rosin) and is taken out through the liquid outlet 47. In the method thus described, approx. 8o% of those in the differential evaporator -condensate or an 11 inflowing vapor as liquid through the liquid outlet 47, and the liquid contains approx. 97% rosin, which is mainly free of unsaponifiable and colored substances, while approx. 20% is withdrawn as liquid from the condenser 19 as tallow oil distillate containing 25% resin.

If one wants to produce a product for emulsion polymerization of butadiene and styrene, the fatty acids drained through line 65 are hydrogenated so that the linoleic acids are preferably converted into oleic acids, after which the fatty acids are converted into either a sodium or potassium soap, which is to be used as an emulsifier for emulsion the ion polymerization reaction, whereby this becomes a rational economic method for obtaining a source of low-titer soap for low-temperature polymerization in the manufacture of rubber. The low-titer soaps from other oleic fatty acid materials are so expensive that their use in the rubber process becomes almost prohibitive.

When the apparatus is in operation for the production of refined fatty acids from cotton seed oil refining residues, the evaporator 11 and the condenser 19 work as total condensers, whereby no heat is supplied to the vessel 11, and the lower boiling palmitic acid fraction is withdrawn at lines 63 and 65, the high boiling olefinic fraction at outlet 47 and the rest at outlet 34.

From the foregoing it appears that devices and methods according to the invention provide completely satisfactory rectification with minimal heat-induced cleavage, resin formation, polymerization and similar uneconomical or undesired reactions. Such benefits are largely believed to be primarily a consequence

of the differential evaporation and the differential condensation, whereby the liquid and vapor streams run counter-currently, so that a concentration gradient is obtained along the apparatus with regard to both the liquid stream and the vapor stream in counter-current. The liquid phase that is heated thus does not reach an equilibrium concentration as in the usual method for distillation, and the constant enrichment of this during its passage through the apparatus results in a selective return to the liquid stream of vapor fractions that are condensed at special points where fractionation of the components in these can be brought to a maximum most quickly with a minimum operating content of heat-sensitive components in the liquid phase.

Further advantages along these lines are further believed to be due to the fact that, according to the invention, relatively thin liquid films are used which are heated on the heated plates. Especially under high vacuum in the device according to the invention, there is thus a pronounced sloshing effect while the thin liquid film evaporates, which leads to a powerful jet or a powerful cloud of small liquid droplets which are constantly thrown directly over the heated surfaces and perhaps reach 2o or 25 cm up in the steam room. These small droplets provide a large surface area of liquid, perhaps 1500 times the liquid area of the original film in intimate contact with steam, thus promoting high rates of thermal diffusion and mass transfer, leading to high rectification efficiency.

Apart from the fact that the invention makes it possible for components of a liquid mixture to be separated into fractions at a theoretical bottom, it brings even more effects in separation and fractionation by the fact that vapor fractions are released by differential condenser means.

When such different vapor fractions are returned or added to an evaporating and moving liquid film by differential condensation and countercurrent flow, the rectification is further increased as the fractions are again fed into the moving and evaporating liquid film at a point in the flow, where the composition of the liquid film corresponds to the composition of the returning or previously evaporated fraction. Thus, the differential removal of components from the starting mixture is carried out together with subsequent separation or rectification of individual components in the vaporized fractions and with continuous division of a liquid mixture into several different fractions by means of the apparatus and then collection of such divided fractions for further rectification at different points along the system according to each individual faction's particular composition.

Either such collection and division according to the invention is carried out

in a single unit, e.g. the differential evaporator-condenser lo or in several of the interconnected individual units is a matter that primarily concerns the special material being processed, the compositions and the purity of the desired special fractions that are finally to be separated and similar factors. Either separated vapors are taken out and condensed by such condensers as 12 or 17 at the extreme end of the apparatus, or by other or additional condenser means arranged at

other points along the apparatus, factors are also largely determined by the particular materials being processed and the particular results desired. Partly as a result of an effect of sloshing and strong expansion felt during evaporation of the very thin liquid films, and perhaps partly as a result of the presence of a high vacuum provided on the system, vaporized materials rising from the heated plate have sufficient vapor velocity to proceed to the nearest condensing surface with a minimum of diffusion with vapors into adjacent parts of the apparatus, and such rate factors are likewise suitable to ensure that a stream of vapors is separately directed into the nearest accessible condensing device, whether this is only the cooled condenser surface 45 or such an extraction condenser as 12 or 17. Similarly, either a separation or a change in the direction of the steam flow is achieved by the condensation being interrupted at the upper part of the device (such as in the case of insulation 32) or alternatively by the path of the steam flow being physically is caused to be interrupted by arranging individual units with continuous v box strbm in between, the desired high degree of separation and rectification is still achieved according to the invention.

In order to particularly illustrate the foregoing, fig. 5 and 6 an adaptation of the present invention to a plant for treating tall oil, where several more or less modular differential evaporation-condensation or division and collection units are used for the fractionation of tall oil components into a significant number of fractions, each of which further rectified and collected in such a way that two or three highly concentrated, purified rosin, fatty acid fractions and intermediate fractions are finally obtained.

With regard to such a system and the results to be achieved with it, it can reasonably be stated that the treatment of tall oil according to the invention for the extraction from it of mainly waste products of commercially usable or valuable purified fractions or components, may involve fractionation of the tall oil starting material into the following fractions of commercial usable materials, or the removal of unwanted impurities, such as (a) a colored fraction, (b) low-boiling, unsaponifiable components, (c) palmitic acid components, (d) oleic, linoleic, etc. fatty acid components, (e ) rosin components,

(f) sterol components and (g) trimers.

The color problem, which can be of significant importance when marketing the products obtained, is related to the presence in the crude tallow oil of small amounts of material that is prone to undergo thermal decomposition under the conditions of high vacuum distillation. Preferably, this is provided for the main fractionation by heating the raw material for a few hours under high vacuum and at a temperature just below the boiling point range of the fatty acid components (e.g. approx. lo5-15o°c depending on the vacuum), which treatment either removes the coloring materials and/or stabilizes or "shapes" the unstable materials so that they are no longer volatile and therefore leave a minimal contamination in the later rectified usable fractions of rosin or fatty acid materials to be separated.

The specified palmitic acid, resin acid fractions and the olefinic fatty acid fractions are then separated from the residues and sterols in a series of stages of differential evaporation and differential condensation in preferably several individual, but in series interconnected units, in which the various stages of differential evaporation and differential condensation is carried out for rectification of several fractions with different composition, collection of related fractions and reintroduction of these in subsequent stages of rectification at different points where the composition of the intermediate fraction corresponds to the composition of the liquid phase at the particular point of reintroduction. Final rectification is thus carried out by differential or simple distillation by the bent intimate contact between vapor and jet from the liquid phase film, by differential or simple condensation, by the bent intimate contact between vapor and condensate and by collecting the different fractions and simple re-introduction of these by points along the apparatus where the vapors formed by evaporation from the liquid film are essentially in equilibrium with the particular increment of the liquid phase film from which the vapors originate.

The ultimately desired composition for each particular final fraction can be regulated or dictated to a great extent by varying market conditions for a particular material at a particular degree of purity, and the particular composition or purity for a finally separated fraction is easily regulated according to the point in the system, by from which such a fraction is completely separated in a product. From a tall oil raw material that originally contains approx. 3% palmitic acid, twelve theoretical bottoms in the various processing stages according to the invention (including both differential evaporation stages and differential and rectifying or fractionating condensations) will produce a palmitic acid fraction with approx. 9o%'s purity, which is a known article on the market, and which can be marketed as such and/or further purified or rectified as desired.

Instead of carrying out a complete rectification or fractionation in a single unit (e.g. lo in Fig. 1), one also prefers to utilize a number of individual units (e.g. those in Figs. 5 and 6 described below) so that the part of the liquid material entering the units, in which the largest part of the rosin and the olefinic fatty acid is fractionated, has already become essentially free of unsaponifiable, low-boiling light final fractions and a palmitic acid fraction of the desired purity.

A further fraction rich in resin acids (making up perhaps about 1/3 of the original raw feed) can easily be fractionated so that it contains perhaps 15% rosin mixed with olefinic fatty acids. Such a mixture can be marketed directly as a low rosin distilled product, which is commercially recognized, or further rectified for further fractionation of rosin and fatty acid components.

In any case, after substantially complete removal of palmitic acid components and low-boiling, light final components, rosin and fatty acid components are evaporated until the acid number of the residue is brought down to 5o - loo, depending on the original composition of the raw material and the emerging degree of reflux for the production of the desired commercial products with the desired purity. E.g. gives 14 theoretical bottoms (after fractionation of palmitic acid and light final fractions) fractionation of rosin and fatty acid fractions with approx. 98% purity in each, and satisfactory results according to the invention have been achieved with a substantially pure fatty acid final fraction and a 95% ready-made rosin product of a salable, commercial grade (eg "WO" or "N" rosin). Residues with an acid value of 5o-loo are further rectified and give as distillate a soft dark rosin material and a final residue with an acid value of approx. 4.

The preceding work processes then provide a truly acid-free pitch for steroid fractionation in e.g. a molecular distillation apparatus for the removal of unpolymerized, non-esterified steroid materials to be sold as a known crude steroid material, while the residue obtained is then satisfactorily saponified, slightly acidified, washed, neutralized so that further refined steroid material can be removed by further molecular stripping. Alternatively, the stream can at approx. 5o-loo acid number is sold as such but as a recognizable commercial product, and each of the first or other steroid fractions has its commercial applicability.

To further elucidate the adaptation of the invention to such processing of tallow oil, reference is made to the flowchart in fig. 5, i

which shows an arrangement of an apparatus according to the invention and a working sequence of processing steps. In fig. 5, there are thus several divider or differential-evaporator-condenser units I0I-I06, each of which has one or more deflegating condensers and is generally constructed according to the description below, which refers in particular to fig. 6, and all the units are connected in the desired series or sequence for the sake of a liquid phase flow through all six units. In the line with treatment material flow, a pre-treatment unit lo7 is arranged for drying or dehydration, deaeration and thermal decomposition of the coloring materials in a raw tallow oil material from a raw material source lo.

In the flowchart in fig. 5, lines for the flow of tall oil jemates in the ale, which are processed in the system, and the products produced from them are indicated with solid lines, while the vacuum flow device on the system is indicated with double lines, and the heating fluid flow to the various specified elements of the apparatus is indicated with dashed lines, the directions of flow of the respective materials through the respective lines are indicated by arrows on the lines.

Although the operation of the entire schematically reproduced system is essentially to be continuous, one still wishes to keep the material to be processed for perhaps 8 hours at a temperature (below the fatty acid boiling range) of approx. lo5-15o°C under the very high vacuum (pressure down to 2 mm Hg or less) to stabilize the thermal decomposition, which can be expected, of coloring material for dehydration and preheating, as previously described for the vacuum dryer 61 in the device according to fig.

1. To accomplish this, the preheating unit 107 is allowed to contain an evacuated atomization chamber 100 which is connected to the vacuum system by means of a line 111, and which has an atomization head 112 for receiving and finely distributing or heating and expanding raw tall oil material from the inlet loo and at the desired flow rate for the entire system's processing capacity per unit of time (e.g. 1400 kg/hour) for introducing the material as a jet into the evacuated atomization chamber 110 and a vacuum column 113 connected to it. However, in order to keep the material in the pretreatment unit 107 for as long as 8 hours before feeding into the pre-treated crude tallow oil in subsequent units in the system, a recirculation system has been arranged which comprises a heat exchange column 114 with a recirculation pump 115 and a recirculation atomization head 116, which is designed and dimensioned for a recirculation throughput capacity of 8 times that of the atomization head 112. Valves 117 and 118 are arranged for regulating the material flow through the unit lo7 which is to be recirculated either through the heat exchanger 114 or through a parallel heat exchanger 119, from which the liquid supply is introduced into a first differential-evaporator-condenser unit loi by means of a led-

ning 12o.

A main system is arranged for heating the various elements of the apparatus shown schematically with a heating liquid and is generally indicated as a conventional, known "Dowtherm" heating system with a heat source 125, from or over which heating liquid is circulated through a certain branching device for supply and return of liquid by lines 126

and 127 with a pump 128 for feeding various elements in those in fig. 5 with dashed lines for current devices.

Part of this heating system is used for heating the heat exchangers 114 and 119 (such as with the supply lines 129 and 13o and return lines 131 and 132 for the heating liquid). The different return lines for heating fluids from the different elements of the device are collected in a header 135

for regulation of these, and the flow of heating fluid for the entire system is regulated by the various valves indicated as group 136 with respective flow meters 137 for regulation of all "Dowtherm" return lines with return flow, which is sent back to header 127.

Tall oil to be treated is introduced at loo into unit lo7, where it is preheated and dried and held for approx. 5-8 hours at a high altitude

0 temperature (but below the temperature range for boiling or thermal decomposition of the desired, usable components, which will later be fractionated) and while maintaining a high vacuum in the system. From the pre-treatment unit lo7, the material to be treated is introduced via line 12o to the liquid inflow inlet for the differential-evaporator-condenser-fractionation unit loi , which comprises (which is more clearly shown in Fig. 6)

a substantially horizontal, elongate evaporator-condenser zone or equivalent portion (mainly as described in connection with the device in Figs. 1-4) with a heated plate 14o, along which a thin liquid film flows and from which differential evaporation is achieved, and an upper, elongated differential condenser surface 141 above the heated plate 14o for differential condensation of the material evaporated from the plate 14o. At the upstream end of the liquid flow through the unit loi, a deflegating condenser 145 is arranged with several condenser outlets 146 and 147 at many different levels for con-

densat removal, as described below. The plate 14o of the unit loi is heated by circulation of heating fluid from the "DowtherrfJ system, which is shown by a feed line 148 and a return line 149 - although this system is omitted in Fig. 6 for simplicity, and the system is arranged with the heating plate 14o on substantially the same manner as previously described in connection with fig 2.

Each and every one of further units lo2 -lo6 likewise contains mainly horizontal and elongate differential evaporation plates (respectively 15o-154) and condenser surfaces lying above them (respectively 155-166) and one or more rectification condensers (I60-I66), which are arranged at the upstream ends of the liquid stream along the respective horizontal plates (except for the additional condensers 162 and 163 in the unit lo3) with several condensate outlets in each condenser.

All differential evaporation plates 15o-154 are heated by circulation of heating liquid from the "Dowtherm" system, which is shown by dashed lines in fig. 5, although special reference and explanation of each wire is not considered necessary here, as the processes are completely clear from the drawing. Those in fig. 5 and fig. 6 schematically shown units are generally constructed according to the previous explanation for fig. 1-4, and no further reference to the details is made here. The top of each of the capacitors 145 and I60-I66 is connected (as with respective vacuum lines 170-177) to the main vacuum circuit board 178 for maintaining the desired vacuum on the system and/or to an auxiliary vacuum line 179, which maintains the desired ratio for reduced pressure in the pretreatment unit lo7.

Satisfactory results have been obtained in such an arrangement of the apparatus for setting a tall oil processing capacity of approx. 14oo kg/hour with the units lol-lo4, where respective heated plates have a length of approx. 5.5 m and a width of 1.2 m, and with the respective horizontal condenser surfaces approx. o.9 m above the plates. Comparable appropriate dimensions for units lo5 and lo6 are 9.1 m length and 1.2 m width and o.9 m height. Satisfactory results are also obtained with the dephlegmating condensers 145 and 16o, which are approximately 6.4 m high and 0.9 m in diameter, with the various condensate outlets at suitable heights, as described below for the intended purpose, and with catch rings for. condensate around the inside of the condensers and vertically arranged with approx. o.5 m's space. The dimensions for the capacitors 161-163 are likewise 5.5 m high and 1.2 m in diameter with the same ring arrangement, while the capacitor 164 is appropriately 6.4 m high and 1.2 m in diameter and the capacitors 165 and 166 are fully sufficient with a height of 7 ,3 m and diameter 1.2, as each one has a water jacket 185 and 186 in a known manner and for the circulation of coolant through this to cover the desired condensation effect, and these water jackets are located in the upper half of the condenser,

however, below its peak.

With regard to the volume of material in fig. 5, two condensate fractions are removed from the condenser 145 of the fractionation unit loi through the outlets 146 and 147. The lowest boiling of these fractions is introduced into the condenser 16o of the unit lo2 at 19o, while the highest boiling fraction from the unit loi is introduced as liquid feed into the upstream liquid inlet end of the unit lo2 and forms a liquid phase film over the heated plate 15o in the unit lo2. Condensate is withdrawn from the condenser 16o at 192, which condensate mainly contains low-boiling and unsaponifiable light final fractions, which are introduced together with other low-boiling distillate materials from units lo5 and lo6 or collected elsewhere in a distillate collector tube 193 to a storage tank 194 for light final fractions, preferably through a liquid lock 195 and a flow regulator 196 in a completely known manner.

Flowing liquid from the unit loi is sent out at its downstream end 199 for the liquid flow and introduced into the unit lo3 upstream end 2oo for the liquid flow. If the units lo3 and loi are completely separated, this does not have any decisive significance in this connection, provided that the flow of liquid phase through the units loi and lo3 etc. is continuous, while the flow of vapor is countercurrent to the liquid flow in the aforementioned parts of reaction or the rectification steps in sequence. As previously mentioned in connection with fig. 1, an essentially continuous flow of liquid is maintained from left to right in the differential evaporator lo, when counter-flowing steam flows in this are caused to split up. I.e. insulation that prevents condensation at the right part of the unit means that the vapors to the left of the isolated part (by means of the vacuum system or other conditions of partial pressure) are drawn to the condenser 17 when the vapors in the isolated part take the opposite direction towards the condenser 12. Some simplification of installation and perhaps operation can be achieved by arranging individual, separate modular units, such as loi and lo3, to contain and regulate the oppositely directed vapor flow, while continuous liquid phase flow is maintained through these. Control of the direction of the vapor flow etc can be achieved by taking into account the thermodynamic laws or the gas laws and by actually physically interrupting or separating the vapor phases above the continuous, flowing and evaporating liquid film through the units loi and lo3.

At this particular point in the fractionation and rectification in sequence of the aforementioned different components of tallow oil, the primarily desired function for the unit lo3 is to collect several fractions with varying compositions. F61-like, it is primarily the fractionation or rectification obtainable in the unit's lo3 respective capacitors 161-163 (and also the unit's lo4 capacitor 164) that is desired here. It is thus preferred to have all horizontal outer surfaces of the unit lo3 so insulated (or otherwise temperature-controlled) that the condensation on the horizontal surface 156 of the components evaporated from the heated plate 151 in the unit lo3 is really brought down to a minimum with the result that the vaporized components are condensed in the condensers 161-163 and form a limited and separable number of fractions instead of that with continuous differential condensation in the other units with uninsulated or cooled, upper, horizontal condenser surfaces attainable, infinite composition gradient. Several outlets are arranged at different heights in the respective capacitors 161-163 (and also in the unit's lo4 capacitor 164) that a number of intermediate fractions or partially rectified fractions are separated, as each one has a special composition and has more or less of the desired special rosin and fatty acid materials, which must finally be completely rectified and separated from each other.

In the specified embodiment, each one of the capacitors 161-164 has two condensate outlets 201-208 according to fig. 6. Since none of the fractions separated at the condensate outlets 2ol-2o8 is (or is considered to be) a final rectification of a particular desired final component of the original mixture, it is the particular composition for each. fraction (or even the particular number of individual fractions) not particularly decisive according to the invention. The desired first result is the separation of condensable vapor phases at this point in the process into a significant number of different fractions with different amounts or compositions of the respective, particularly desired rosin fatty acid products, nor is it essential that such fractions be separated in units lo3 and lo4 at points of vapor conditions which bring the concentration of the particular desired product to a maximum. The main purpose here is to produce a plurality of differently structured intermediate fractions, each of which can then be re-introduced into the unit lo5 at a special point along the dough, where the composition of the vapors that evaporate from the liquid phase in the unit lo5 essentially exactly corresponds to the composition of the separated fraction from the units lo3 and lo4 which are reintroduced in this point. The increased rectification efficiency or closeness, which according to the invention is achieved by the units lo3, lo4 and lo5 united' collection or separation results or steps, is believed to have been achieved more by the second stage rectification of several fractions, which are introduced into the liquid vapor system in the unit lo5 at the very right point, than by such advantages as relate in another way to the accuracy or efficiency of a particular separation or rectification in the units lo3 and lo4.

The respective separated fractions 2o2-2o8 from the units lo3 and lo4 condensers 161-164 are thus introduced into the elongated, horizontal, differential condensation and evaporation unit

lo5, such as through the upper differential capacitor surface 158 at the various separated or horizontally spaced points, indicated in fig. 6, each of the condensate fractions from units lo3 and lo4 being introduced into unit lo5 by

the particular point along this, where the composition of the fraction corresponds to the vapor phase atmosphere along this point along the unit lo5, where each one of the fractions 2o2-2o8 is introduced. The lowest boiling fraction 2ol, which is shown in fig. 6, may preferably be introduced into the device lo5 condenser 165 rather than into its evaporation zone.

There is also a continuous liquid phase flow between the units lo3 and lo4, as the liquid outlet flow from the unit lo3 is led over a line 21o to the unit lo4's upstream inlet for liquid flow. As previously explained with regard to the units loi and lo3, it is primarily a measure of expediency to arrange the separate units lo3 and lo4 compared to the expedient, if necessary, to arrange vapor flow which is interrupted by a number of different bodies, while the liquid phase flow is continuously maintained through all the units loi , lo3 and lo4.

Regarding the liquid flow through the units lol-lo4, the evaporative separation (though perhaps not complete rectification) of volatile components from the original, liquid raw material has been completed in the unit lo4, that the liquid outflow from this, which is caused to flow out by downflow -end through conduit 215, may be considered the above-mentioned concentrate, whether or not this concentrate may or may not be further separated or refined or processed to produce sterol fractions etc., and this liquid stream is made to flow into a pitch tank 216, preferably through a liquid lock 217 and a valve and flow regulating device 218, The liquid outflow from the unit lo2 (in which the final fractionation or rectification of light final fractions is achieved) is similarly sent from the unit lo2 downstream to the upstream liquid phase stream along the unit lo5 by means of a line 22o for to leave a part of the liquid phase film in the unit lo5 for differential evaporation in this at different points along this and at different steam compositions, in which the corresponding condensate fractions 2o2-2o8 are introduced. The liquid outflow from the unit lo5 is the desired final rosin fraction which is sent out from the unit lo5 downstream through a conduit 225 to a rosin tank 226, preferably with a liquid trap 227 and a flow regulating or recording device 228. Further rectification and fractionation of what one can be considered to be mainly a binary mixture of fatty acid components and resin acid components which are introduced into the unit lo5 from a number of different points in the process, is mainly achieved by this, as a fatty acid-enriched, condensable fraction is taken out from the unit lo5 condenser 165 through a condensate outlet line 23o, and a further light final fraction is taken out upwards from the condenser 165 through a line 231, which fraction is to be combined with other light final fractions in a collecting tube 193.

Depending on the desired final rectification (as above is

mentioned with regard to fatty acid components or fractions rich in them) the fraction withdrawn from the condenser 165 or the unit lo5 through the line 23o can be further fractionated, rectified or purified by introducing it again into the unit lo6, e.g. in that it is introduced into the condenser 166 and forms back-flowing and condensable fractions in such a way that a further liquid phase film appears along the heated plate 154 of the unit lo6, which film flows downwards in this from the place of the condenser 166 and forms a further liquid-shaped, rosin-containing outflow fraction which is collected in a tank 235 by means of a line 236 from the unit lo6 downstream, the aforementioned preferred device with a liquid lock 237 and a flow device 238 being present. Optionally, shown as optional with dashed lines, additional reactants,

e.g. phthalic anhydride and/or maleic anhydride, etc. are introduced into the horizontal differential evaporator and condenser section of the unit lo6 for reaction in this in the anhydrous vapor phase with the components of the unit lo6 in such a way that, according to the invention, a further improvement of the end product is produced, such

such as by the formation of adducts, which help with further fractionation of the various components and/or raise the acid number, react with phenols in the system, etc. as described below.

The final fraction enriched in fatty acids is separated

off from the condenser 166 in the unit lo6 at a suitable point along it through a line 24o and is led from this to a fatty acid tank 241, again over a liquid lock 242 and a flow mechanism 243. A distillate fraction of light final fractions is also removed, if so is necessary, from the upper part of the condenser 166 through a line 245 and is collected with other light final fractions in the collection pipe 193. In fig. 3 shows a drip line 25o, which is preferably arranged to collect condensate from the vacuum system's collection tube 178 and to feed such droplets to a tank 251 through a liquid lock 25 2 and a flow regulator 25 3.

The following example will further illustrate methods for commercial operation according to the invention, whereby the device described above is used. Rectification and fractionation are generally carried out as follows using a commercial tall oil material at processing capacities of

about. 14oo kg/hour. The tall oil raw material (after it has been subjected to the pre-treatment in unit lo7, where it was kept for approx. 8 hours in a high vacuum and at 163°C for color stabilization etc.) can thus be considered to contain (in parts by weight) approx. 156o parts rosin, 8ol parts fatty acids, 9o parts light final fractions, 12o parts palmitic acid fraction and 429 parts pitch,

when the pre-treated material was fed into the unit loi through the supply line 12o. At the stated treatment capacity of 1400 kg/hour, there was a liquid outflow in the unit loi through line 199, which was fed into the division unit lo3 as a mixture containing approx. 138o parts rosin, 441 parts fatty acids and 429 parts pitch, while the steam mixture which quickly entered the condenser 145 of the unit loi contained approx. 18o parts rosin, 36o parts fatty acids, 9o parts light final fractions and 12o parts palmitic acid fraction.

These vapors were condensed in the condenser 145 and gave at outlet 147 a mixture containing 25 parts rosin, 167 parts fatty acids, 25 parts light final fractions and 33 parts palmitic acid fraction. The later fractions were fed into unit lo2 where they were further divided into a light end fraction at outlet 192, which fraction contained 6 parts rosin, 84 parts fatty acids, 9o parts light end fractions and 12o parts palmitic acid fraction (which mixture showed an acid number of 145), while the liquid outflow from the unit lo2 (which was led through the line 220 to the unit lo5) contained approx. 174 parts rosin and 276 parts fatty acids.

The mixture of rosin, fatty acids and pitch which was introduced into the liquid inlet 2oo of the unit lo3 was separated in this into six condensed fractions and a liquid outflow. When the liquid moved along the heated plate 151 of the unit 103, the vapor mixture that was introduced into the condensers 161-163 was as follows: into the condenser 161 was introduced 135 parts of rosin and 165 parts of fatty acids, into the condenser 162 was introduced 216 parts rosin and 84 parts fatty acids and in the condenser 163 231 parts rosin and 69 parts fatty acids were introduced. The. condensate mixtures that were separated and removed at the various condensate outlets 2ol-2o6 were as follows: at 2ol: 30 parts rosin and 70 parts fatty acids; at 2o2: 55 parts rosin and 45 parts fatty acids; at 2o3: 63 parts rosin and 37 parts fatty acids; at 2o4: lo5 parts rosin and 95 parts fatty acids; at 2o5: 151 parts rosin and 39 parts fatty acids and at 2o6: 168 parts rosin and 32 parts fatty acids. The liquid discharge from unit lo3, which was introduced into unit lo4's waste supply inlet through line 21o, contained approx. 798 parts rosin, 123 parts fatty acids and 429 parts pitch.

The treatment of differential evaporation and condensation in the unit lo4 forte to a vapor mixture which was introduced into the condenser 164, with approx. 777 parts of rosin and 123 parts of fatty acids, while 45o parts of pitch (at an acid value of about lo) were taken out through the liquid outlet 215 from unit lo4. The condensate mixtures removed from the condenser 164 contained the wood outlet 2o7 approx. lo8 parts rosin and 42 parts fatty acids and at the outlet 2o8 approx. 669 parts rosin and 81 parts fatty acids. The preceding condensed vapor fractions 2ol-2o8 from units lo3 and lo4 together with the liquid outflow from unit lo2 were introduced at the various points shown along the collection unit lo5 to produce a liquid resin acid fraction at unit lo5 outlet 225, which fraction contained approx. 14ol parts rosin and esters, 29 parts fatty acids and 2o parts unsaponifiable components, while the fatty acid fraction condensate removed from the condenser 165 at outlet 23o contained approx. 716 parts fatty acids, 80 parts resin acids and 4 parts unsaponifiable components.

For explanatory purposes, special points of view are given below on how, according to the invention, the approximate location of the inputs for the fractions 2ol-2o8 in the collection unit lo5 is determined. It is desired that each one of these fractions is introduced into the differential-evaporator-condenser part or phase of the unit lo5

at a point along this, where the particular entering mixture is essentially the same as the liquid phase at this point the unit lo5 and in particular with regard to the rosin content of the different entering fractions. The condensate from the outlet 2ol has the lowest rosin content (approx. 3o%) and is thus introduced directly into the condenser 165 together with the steam mixture produced in the differential evaporator 15 3 by the unit lo5 (e.g. approx. o.9 m above the horizontal condenser surface 158). The liquid outflow from the unit lo2, which is introduced into the unit lo5 via the line 22o, contains approx. 38.7% rosin and is thus introduced for practically immediate evaporation in the condenser 165.

The rosin amounts for the remaining condensate efforts 2o2-2o8 are approximately and in descending order 5 2.5% for 2o4, 55% for 2o2, 63.o% for 2o3, 72.o% for 2o7 8o.o% for 2o5, 84.o % for 2o6

and 89.o% for 2o8. These different mixtures are respectively introduced along the unit lo5's horizontal evaporation condenser 158, 15 3 in the preceding arrangement, whereby one reads from the condenser 165 towards the opposite end of the unit lo5 and one considers the unit's horizontal extent of approx. 9.1 m to be completely sufficient (though only for illustrative purposes) for de-xvarious with

Space extends this arranged inlet. Wire 2o4 is connected approx. 2.1 m from the condenser 165, inlet 2o8 approx. 3.4 m from the lo5 opposite end of the unit and the remaining wires are arranged in between in accordance with the rosin content of the mixtures. Thus, a 0.6 m space between the units 2o6-2o8, 2o5-2o6 and 2o2-2o4 is fully sufficient, while approx. 1.2

m is preferred between 2o2 and 2o3 and only approx. o.3 m between 2o3-

2o7 and 2o5-2o7.

In the fatty acid purification unit lo6, the aforementioned fatty acid fraction was introduced from the condensate outlet 23o of the unit lo5 (and containing approx. 89.5% fatty acids) to the condenser 166 of the unit lo6, while a reactant, containing approx. 80% maleic anhydride and 20% phthalic anhydride, were preferably introduced at line 238 for reaction therein. A fatty acid fraction withdrawn for final division at line 24o actually contained all the fatty acids with a purity of 99.9%, while a liquid rosin-containing fraction was removed at liquid outlet 236, and this fraction contained approx. 84 parts material, including 95.6% concentrated resin acids and the rest unsaponifiable material and esters.

There are a number of different end products (of which each

and one of course is mainly a mixture), which can be produced from tallow oil according to the invention, depending on operating conditions, additives, etc. For this reason, the special designations used here for the product fractions are not considered to be limiting. Within the tall oil trade, there are a number of well-known classes or designations for different end product fractions that can be obtained from the distillation of tall oil. E.g. "tall oil rosin", as a commercial quality or product, is generally considered to be a mixture of rosin containing at most 5% fatty acids, while "tall oil fatty acids" can generally be considered a commercial product mixture of olefinic fatty acids, including at most 5% rosin and the designation " distilled tall oil" generally refers to a third product from tall oil distillation which contains a mixture of olefinic fatty acids and rosin, which mixture has more than 5% rosin but is otherwise predominantly fatty acids.

Generally speaking, the rosin (or resin acid) fraction can be commercially utilized as a source of rosin for purposes where fatty acid contamination of at most 5% is not a nuisance, while the fatty acid product can likewise be utilized as a source of olefinic fatty acids for purposes where contamination with a heavier rosin material of at most 5% is not embarrassing. The third fraction or intermediate fraction has its own commercial application under conditions where relatively pure fatty acids or relatively pure rosin are not required. In commercial terms, it is generally economic considerations that determine how much effort or cost can be allowed to reduce the production (or in fact further rectify or fractionate) of such a third distilled product to a minimum, which product in reality is a mixture containing far too much rosin to be "fatty acid" and far too much fatty acid to be considered "rosin".

There is such a third product which is removed from the unit lo6 liquid outlet at line 236, Whether such a product meets the specifications for "distilled oil" or "concentrated rosin", etc. depends on the composition of the mixture at this point, and thus in primarily of the operation of the units lo5 and lo6 and in particular of the utilization of a reactant in the unit lo6 through line 238. Under certain market conditions or for certain operational purposes one can sell the intermediate fraction distillate,

which is withdrawn at unit lo5 line 23o, as "intermediate fatty acid" or "distilled tallow oil", and sell the waste effluent from unit lo5 as commercial "rosin". Alternatively, a further rectification of such fatty acid mixture is achieved in the unit lo6, whereby a purer fatty acid product becomes available at outlet 24o and a third product of commercial value as a liquid outflow through line 236.

The special compositions of these products from the unit

lo6 can be changed in a number of different important ways, such as e.g. utilization of a reacting agent. I.e. material such as phthalic anhydride, phthalic acid or other materials which react with phenolic components in the mixture, improve the final color properties of the fat extracted through line 24o

acid materials (several of which coloring materials are phenolic and lie within the boiling range of the fatty acids) by forming higher boiling products, which are thus removed from the fatty acid fraction extracted through line 24o. In a similar way, maleic anhydride, maleic acid and similar known reactive agents, which have a reactive double bond in a similar structure, react with ease in the anhydrous vapor phase in the unit lo6 for the production of higher boiling . materials from the components therein, whereby the fatty acid content in the distillate withdrawn through line 24o is further purified.

To the extent that the products of such reactions in the unit lo6 produce heavier or higher boiling products that must be included

in the liquid effluent through line 236, they increase not only the purity of the fatty acid distillate, but also the heavier (or at least non-fatty acid) content of the liquid effluent and yield, if desired, from line 236 a commercial product known as "concentrated rosin", with increased commercial value for any application purposes. A number of other chemical reactions with the various material components introduced in the unit lo6 are carried out easily and sufficiently in anhydrous vapor phase form to further change the special composition of the end products finally separated at the unit lo6, each of which can of course be further rectified or fractionated in subsequent steps, if desired, and in a known manner.

The various illuminating dimensions and devices indicated here relate to the tall oil distillation example and must not be considered to be limiting or of general adaptation to all organic, liquid mixtures with which satisfactory results can be obtained according to the invention. More generally, the processing capacity of the entire system is limited primarily by the ability of the first units to essentially completely remove all species of light final fractions and unsaponifiable materials found in the first feed. The length and width of the various units in each particular distillation are then determined with ease according to the invention and of course with regard to factors known in the art. E.g. with each given L-shaped unit, the width is primarily important (in addition, of course, for structural considerations for the supply of a unit in the preferred cross-sectional shape according to Fig. 2) to ensure sufficient heating area for vaporization of all components that one wishes to vaporize in this unit, while the length of each individual unit relates more to the differential evaporation and differential condensation required to produce at least one pure component from a binary mixture feed.

Such width dimensions can generally be varied equally from o.3 to 2.5 m, although for a number of different reasons 1.2-1.8 m is preferred. With these mixtures of materials with close boiling points a length of 5.5 is generally considered -6.1 m (for described apparatus) to be necessary for the removal of a clean component in each unit, although longer or shorter units may be used, as conditions dictate. With regard to such a separator purity as the unit lo3, the most important calculation norms revolve around the trace goal of making the unit long enough to get all volatile components in it appropriately vaporized and having on hand enough capacitors (or capacitor outlets) to achieve as many fractions as desired . As with the unit lo3 one primarily desires evaporation and division of vapor fractions (instead of continuous differential condensation along its horizontal surfaces), it may be preferable to insulate the upper horizontal parts of the unit in order to prevent condensation in it, which is desired in the other units.

The maintained real temperature conditions at the heated plates can be varied over wide limits. With regard to the various tall oil components in the illustrative example, the olefinic fatty acid fractions can be considered to have a boiling range of approx. 19o°C level under these vacuum conditions, while rosin boils around 2oo°C. Under such

circumstances give temperature ranges that lie in the area approx. 2oo-32o°C and preferably 265-28o°C satisfactory result, provided that sufficient condenser surface is available at the unit. The amount of added heat per unit of time (and/or the temperature difference between the heated plate and the boiling point of the different liquid mixtures that evaporate, on the other hand) can naturally have a significant impact on the amount of evaporation per time unit (and perhaps the above-mentioned sloshing effect), but satisfactory operating results have been achieved for tall oil using the described device type primarily in the above-mentioned temperature ranges.

The increased rectification and fractionation can be attributed to a large extent

the conditions for partial evaporation and partial condensation and creating

maintenance of concentration gradients along the different horizons

say condenser surfaces and/or in the horizontal flowing vapours.

At the same time and even at extremely high vacuum it maintains

the described device such concentration gradients in steam flow

mean and without unwanted diffusion or re-mixing of the vapor stream sent horizontally, while also maintaining advantageous inter-phase transfer conditions perpendicular to the condenser surface. Although the described embodiment is shown for operation at high vacuum, improved results are also achieved at high pressure, perhaps primarily on

due to the contribution of interphase mass transfer to the total effect. IN

in any case, the partial evaporation and partial condensation produce

tion according to the invention continued enrichment of the respective phases,

either at extremely high vacuum or even at atmospheric el-

produces higher pressures, as the vapor stream flows parallel to the liquid stream and perpendicular to the direction of evaporation from liquid to vapor phase.

Claims (20)

1. Procedure for fractionating a liquid mixture of organic substances, e.g. tall oil, rosin and the like, with close boiling points in at least a higher fraction, by which method the mixture is fed along an elongated path in a horizontal evaporation zone to gradually increase the temperature of non-evaporated components of the mixture, and where lower boiling components are evaporated at one end of the zone and the lower boiling components are separated from higher boiling components, characterized in that the mixture is continuously fed into a first unit (103) with an elongated horizontal evaporation zone (151) and is evaporated in this so that a stream of steam is formed, that the stream of steam is separated into several steam fractions with different contents of the components of the mixture, that the steam fractions are condensed, that the obtained condensate fractions (201 - 206) are fed into a distance from each other in another unit (105) with an elongated, horizontal evaporation zone (153), that the condensate fractions are continuously brought to flow along the evaporation zone (153), that the flowing condensate fractions are continuously heated for differential evaporation of their components at successive points along the evaporation zone (153) in such a way that one essentially continuously currents of other vapors are formed, that these other vapors continuously bring es to flow through an elongate, horizontal condensation zone (158) above and substantially parallel to the evaporation zone (153), that successive condensation of the components of these other vapors is carried out at successive points along the condensation zone (158), according as the flow of other vapors is made to flow through this, as the flow of other vapors is directed in a countercurrent direction the liquid flow inside the evaporation zone (153), that the condensed components from the condensation zone (158) are fed back to the evaporation zone (153) at points in the counterflow direction of the points at which the condensed components were evaporated, that those rich in lower boiling components vaporize continuously' is taken out from the condensation zone (158) and that high-boiling components rich, non-evaporated residue (225) is continuously taken out from the evaporation zone (153) at its downstream end. 2. Method according to claim 1, characterized in that all zones are kept under high vacuum (up to 2 Torr) during the entire course of the steps for evaporation, condensation and withdrawal. 3. Method according to claims 1 and 2, characterized in that the vapors (fractions) rich in lower boiling components are taken from the condensation zone (158) at points upstream in relation to the points where the condensate fractions (201 - 206) are introduced. 4. Method according to claims 1-3, characterized in that the condensate fractions (201 - 206) are introduced into the second unit (105) in a predetermined order, with the condensate fraction richest in higher boiling components being fed to the downstream stream of the steam stream in such a way that the lower boiling fractions is introduced closest to the upstream end of the zone and that the remaining fractions are introduced further downstream in the zone, the higher their boiling point. 5. Method according to the preceding claims, characterized in that at least one of the vapor fractions is differentially condensed in the first unit (103) in such a way that at least two subcomponents (201, 204) are formed, one of the subcomponents being richer in lower boiling matter than the second and the sub-components are introduced into the second unit (105) in the respective sequence for reducing the high content of higher boiling components. 6. Method according to claim 5, characterized in that all steam fractions are differentially condensed in such a way that at least two subcomponents (201, 204$ 202, 205; 203, 206) are formed. 7. Method according to claim 6, characterized in that the mixture from the unit (105) consists of a condensate fraction of the vapors rich in lower boiling components. 8. Method according to claim 7, characterized in that the non-evaporated component (210) of the mixture in the unit (103) is taken out at the downstream end of the evaporation zone (151), that this component is further evaporated in a third unit (104) connected to the unit (103) ) with a horizontal, elongated evaporation zone (152), that at least one vapor fraction is formed in this zone (152), that the vapor fraction is condensed and that the condensate fraction (207, 208) is introduced into the unit (105). 9. Method according to claims 1-8, characterized in that the mixture consists of a non-evaporated residue (199) rich in high-boiling components which is taken out from a fourth unit (101) arranged in front of the first unit (103) with an elongated, horizontal evaporation zone (140) and an elongated, horizontal condensation zone (141) above and substantially parallel to the evaporation zone (140). 10. Method according to claim 9, characterized in that vapors are continuously taken from the upstream part of the evaporation zone (140) and that the vapors are condensed into condensate fractions (146, 147) which, after condensation, are further separated into their higher boiling and lower boiling components in one unit (101) connected to fifth unit (10 2) with an elongated horizontal evaporation zone (150). 11. Method according to claim 10, characterized in that a residue (220) rich in higher boiling components from the unit (102) is introduced into the upstream part of the evaporation zone (153). 12. Method according to claim 1, where the vapors rich in lower boiling components, taken from the condensation zone, are fatty acid vapors, characterized in that these vapors are condensed in a sixth unit (106) arranged after the unit (105) with an elongated, horizontal evaporation zone (154 ) and an elongated, horizontal condensation zone (159). 13. Method according to claims 1 - 9 and 12, characterized in that the mixture is preheated before it is fed into the unit (103 or 101). 14. Device for carrying out the method according to any of the preceding claims, characterized in that the device comprises a) a first unit (103) for steam fractionation, which unit comprises an elongated, horizontally arranged, closed evaporation and condensation vessel, liquid inlet means (200) for continuous feeding into the vessel of a liquid mixture which is to flow along its bottom, means (151) for heating the liquid in the vessel to produce continuous, differential evaporation of volatile components in the vessel to form an essentially continuous stream of vapors, several condensing means (161, 162, 163) in open flow connection with the vessel for extracting and condensing vapor fractions from the vessel; b) a second unit (105) for collecting the fractions, which unit contains an elongated, horizontally arranged, closed evaporation and condensing vessel for liquid, flowing through it, means (202, 203, 204, 205, 206) for feeding each of the condensate fractions from the condensing means (161, 162, 163) to the unit (105) and for feeding the condensate fractions at spaced different points in the vessel of the unit (105), means (153) for heating the condensate fractions in the unit (105) for carrying out successive evaporation of their components at successive points along the vessel of the unit (105) , organ which in the vessel of the unit (105) forms a condensation surface (158) above the liquid therein, for successive condensation of the components vaporized by the heating, the interior of the vessel being essentially unobstructed for horizontal flow of the liquid and the vaporized components and for returning the condensed components from the condensing surface to the liquid stream, member (165), which is located at a point in the upstream direction for feeding condensate tfractions, for extracting and condensing vapors from the unit (105) and in the downstream direction from the input point arranged outlet means (225) for removing non-evaporated liquid from the unit (105). 15. Device according to claim 14, characterized in that the units (103, 105) are connected to evacuation means for maintaining a high vacuum in the entire device. 16. Device according to claim 14 or 15, characterized in that the liquid inlet means (200) is connected to an outlet means (199) for extracting a non-evaporated residue rich in higher boiling components from a fourth unit (101), which contains an elongated, mainly horizontal vessel for differential evaporation and condensation of liquid components. 17. Device according to claim 16, characterized in that the unit (101) has a steam outlet device, located in the upstream direction from the vessel's liquid stream, for extracting steam, which is rich in lower boiling components, and a device (145) connected to the steam outlet device for condensation of the vapors. 18. Device according to claims 14-17, characterized in that the unit (103) has an outlet means (210) for removing at the downstream end of the vessel's liquid flow of a non-evaporated residue rich in higher boiling components and that this outlet means (210) is connected to an inlet means to a third unit (104), which contains an elongate, horizontally arranged, closed evaporation and condensation vessel, vapor outlet means, located near the upstream end of the liquid stream of the vessel, in flow communication with means (164) for condensing vapors, means ( 207, 208) in connection with the condensing device (164) to feed the condensed vapors to the unit (105) and outlet device (215) at the downstream end of the vessel's liquid flow for removing a non-evaporated residue rich in higher components. 19. Device according to claims 16-18, characterized in that the units (101, 104) are also connected to the evacuation device for maintaining the vacuum in the device. 20. Device according to claims 14-19, characterized in that the vessels in the units (101, 104) also contain means for heating the liquid flow of the vessels.