EP3418352A1 - Method and arrangement for mixing viscosity index improvers in basic oils - Google Patents

Abstract

The process according to the invention serves to incorporate viscosity index improvers (VIV) into suitable base oils. Furthermore, arrangements for carrying out the method are claimed.

The object of the invention is to perform mixing operations of viscosity index improvers in base oils so that a further processing of the mixtures can follow immediately. It is also an object of the invention to develop an arrangement for carrying out the method.

The inventive method allows in a liquefaction chamber mixing a batch of at least 70 wt% viscosity index improver in highly pasty form and at most 30 wt% base oil by introducing heat under inert gas at overpressure and by a fluidic circulation of the liquid components in a secondary circuit. Thereafter, the admixing of the resulting dissolved concentrate into a main stream of base oil of suitable mass corresponding to a target mixture. The method is realized with corresponding arrangements.

Description

The process according to the invention serves to incorporate viscosity index improvers (VIV) into suitable base oils. Furthermore, arrangements for carrying out the method are claimed.

So-called viscosity index improvers (VIV) made of high molecular weight polymers are generally present as granules, highlypaste polymer bales (mixed with a few percent by mass of a base oil) or as a highly viscous, but flowable fluid (mixed with a higher mass percentage of a base oil). Examples of typical VI improvers are polyisobutylenes, polymethacrylates (PMA) and olefin copolymers (OCP), in particular olefinic ethylene-propylene copolymers.

The aim of the incorporation of VIV into base oils is to reduce the viscosity drop in mixtures when the temperature increases. This is achieved by the macromolecules being present as balls at low temperatures, which develop more and more at higher temperatures. Intermolecular interactions in the vicinity of the elongated macromolecules maintain the viscous properties there. The resulting lubricant mixtures can thus be used over wide temperature ranges (multigrade oils) and ensure the required lubricant film thickness even at higher temperatures.

In general, according to the target mixture, suitable amounts of VIV and base oil (eg, 10 wt% VIV and 90 wt% base oil, with the VIV possibly broken up) are placed in a sufficiently large container combined with built-in stirrer, heated sufficiently and mixed under ambient pressure and in the presence of oxygen for a sufficiently long time. Depending on the respective mixing partners, temperatures above 130 ° C may be required. In the literature, the value of the process temperature is left little room for maneuver, because at too low temperatures, no completely homogeneous mixture is formed, or at too high temperatures, the base oil content is damaged. It is helpful to heat the high-viscosity components to a suitable temperature before they are introduced into the mixing vessel in order to increase their flowability. Corresponding to the lowered viscosity, mechanical mixing by means of stirrers improves. The temperatures during the mixing process should be chosen to avoid significant thermal decomposition or undesired chemical reactions.

DE 2932459 C2 presents a method and an apparatus for mixing VIV as a granulate or as a powder in base oil. Here, in contrast to the conventional manner, in a trained as an input sluice metering funnel, the wall is constantly flushed with base oil, the VIV granulate or VIV powder weighed into it and fed the forming VIV base oil mixture in a loop of a colloid mill recycled , Due to the cyclic grinding process, the VIV content in the base oil is better pre-dissolved and the time for the mixing process, which is followed by another agitator tank, is significantly reduced. However, this method is unsuitable for high paste viscosity improvers in bale form.

CN 205127860 U discloses a processing of base oils with a VIV already liquefied in advance by a base oil mixture. First, a partial flow of the base oil and the liquefied and therefore also pumpable VIV is introduced separately into a first boiler and mixed with a stirrer. The thus enriched with VIV premix is then over a mixer line in a second boiler combined with another partial stream of base oil, mixed with another agitator and so diluted to the final mixture. In the blending process shown here, a protective gas is used for overpressure. The individual components, the pre- and the final mixture have sufficiently low viscosity, so that the mixing process takes place at moderate temperatures. The number of revolutions of the agitator motors are sufficiently low that no aging processes with regard to temperature or shear occur. However, this method fails with not yet liquefied, highly pasty VIV in bale shape.

Following the admixture of an already liquefied VIV in base oil, further additives (additives, such as corrosion inhibitors, friction modifiers, antioxidants, etc.) are generally added to the mixture in order to significantly improve the lubricant properties. In EP 519760 B1 For example, such oil additives and lubricants having improved properties are disclosed. In the preparation of the lubricant compositions, the oil additives are placed in a suitable container using a dry inert atmosphere, with stirring and at slightly elevated temperatures (at about 40 ° C - 60 ° C and preferably not higher than about 40 ° C) Base oil introduced. In this way, the oil additives dissolve more easily in the oil and the lubricant is more homogeneous.

In US 20080085847 A1 For example, VIV liquefaction of highly-viscous polymer bales and granules has reportedly commonly used a high-speed shredder or high-speed agitator for liquids to shorten the mixing process between VIV and base oil by rapidly increasing the interfacial area. Furthermore, at temperatures above 100 ° C, a protective gas atmosphere (nitrogen or carbon dioxide) can be used.

1. 1) Durch Temperaturen oberhalb von 130 °C, bei hinreichend langer Prozessdauer und unter Anwesenheit von Sauerstoff und Luftfeuchtigkeit, wird das Grundöl irreparabel geschädigt. Oxydation und Hydrolyse verringern die Polymerkettenlänge und verändern somit die Viskositätseigenschaften negativ. Die ausgebildete Schmierfilmdicke bei bestimmten Temperaturen und bestimmter Scherung ist deutlich verringert oder kann im ungünstigsten Fall nicht mehr aufrechterhalten werden.
2. 2) Zu große Scherraten, etwa durch Schreddern, bewirken eine Polymerdegradation, die ebenso die Schmierstoffeigenschaften negativ beeinträchtigen.
3. 3) Energieverschwendung im Prozess und nachweisliche Alterungsprozesse im Grundöl bei der notwendig hohen Energiezufuhr unter atmosphärischen Bedingungen.

Mischanlagen mit Rührwerksbehältern von 5 m³ bis 10 m³ Volumen, werden mit Wandstärken von 30 mm betrieben, um die mechanischen Belastungen beim VIV-Schreddern und Mischen abzusichern. Die benötigte Wärmeenergie, um solche herkömmlichen Anlagen bei 130 °C zu temperieren, sowie das anschließende Herausbringen der überschüssigen Wärme aus dem System (Ölgemisch und Behälter) stellen sich als doppelt ineffizient dar. Um z.B. idealerweise eine Stahlhohlkugel als inerten Behälter von 10 m³ Volumen mit 30 mm Wandstärke von 10 °C auf 130 °C zu erwärmen, sind ca. 92 kWh nötig. Um 8000 I Grundöl ebenso zu erwärmen, benötigt man ca. 500 kWh. Das Gemisch wird üblicherweise bei 90 °C weiterverarbeitet, d.h. eine Wärmenergie von ca. 197 kWh muss aus dem System Behälter und Ölgemisch abgeleitet werden.Criticisms of the conventional agitator and shredder processes for mixing VIV as granules or high-paste polymer bales in base oils:

1. 1) Due to temperatures above 130 ° C, with a sufficiently long process duration and in the presence of oxygen and humidity, the base oil is irreparably damaged. Oxidation and hydrolysis reduce the polymer chain length and thus negatively change the viscosity properties. The formed lubricant film thickness at certain temperatures and certain shear is significantly reduced or can not be maintained in the worst case.
2. 2) Too high shear rates, such as by shredding, cause a polymer degradation, which also adversely affect the lubricant properties.
3. 3) Energy wastage in the process and proven aging processes in the base oil with the necessary high energy input under atmospheric conditions.

Mixers with stirrer containers from 5 m ³ to 10 m ³ volume are operated with wall thicknesses of 30 mm to protect the mechanical loads during VIV shredding and mixing. The heat energy required to heat such conventional systems at 130 ° C, and the subsequent removal of the excess heat from the system (oil mixture and container) are doubly inefficient dar. For example, ideally a hollow steel ball as an inert container of 10 m ³ volume With a wall thickness of 30 mm, heating from 10 ° C to 130 ° C requires approx. 92 kWh. To heat 8000 l base oil as well, you need about 500 kWh. The mixture is usually further processed at 90 ° C, ie a heat energy of about 197 kWh must be derived from the system tank and oil mixture.

Presentation of the invention

The object of the invention is to develop a process for the incorporation of viscosity index improvers, which are present as a high-paste polymer bales, in base oils. This makes it possible to carry out the mixing operations in such a way that further processing of the mixtures can follow immediately. It is also an object of the invention to develop an arrangement for carrying out the method.

The solution of this object is achieved by the features listed in the claims.

The inventive method allows in a liquefaction chamber mixing a batch of at least 70 wt% viscosity index improver and at most 30 wt% base oil by introducing heat under inert gas at overpressure and by a fluidic circulation of the liquid components in a secondary circuit. Thereafter, the admixing of the resulting dissolved concentrate into a main stream of base oil of suitable mass corresponding to a target mixture. Liquefaction of highly viscous viscosity index improvers tends to be far more difficult as the viscosity of high viscosity VIV is several orders of magnitude higher than for VIV already liquefied with base oil. It is in the invention to a gentle solution mechanism in which only the absolutely necessary heat is introduced into VIV and base oil, and in which the protective gas with overpressure prevents outgassing important components, such as ethylene and propylene from the olefinic copolymers. In the case of OCP, just bound ethylene and propylene provide increased miscibility with base oils.

1. a) Befüllen eines Kessels mit Grundöl (dies erfolgt unter atmosphärischen Bedingungen und Labortemperatur) danach Schutzgasspülen eines Gasraums des Kessels durch abwechselndes Erzeugen eines Grobvakuums mittels einer Absaugvorrichtung und Auffüllen des Gasraums mit Schutzgas mittels einer Schutzgaszufuhr;
2. b) Befüllen einer von einem Hauptkreislauf abgesperrten Verflüssigungskammer mit einer definierten Masse eines Viskositätsindex-Verbesserers, beispielsweise in Form eines Polymerballens, und einer definierten Masse an Grundöl entsprechend der Zusammensetzung eines angestrebten Konzentrats unter atmosphärischen Bedingungen und Labortemperatur;
3. c) mehrfaches Schutzgasspülen aus einem Gasraum der Verflüssigungskammer durch abwechselndes Erzeugen eines Grobvakuums mittels einer Absaugvorrichtung und Auffüllen des Gasraums mit Schutzgas mittels einer Schutzgaszufuhr;
4. d) anschließendes Befüllen des Gasraums der Verflüssigungskammer mit Schutzgas bis zu einem definierten Überdruck;
5. e) Verflüssigen des Viskositätsindex-Verbesserers in der Verflüssigungskammer und gleichzeitiges Überspülen mit dem in die Verflüssigungskammer eingebrachten Grundöl in einem ständigen Umlauf des Grundöls über einen Nebenkreislauf bei einer Temperatur oberhalb einer Löslichkeitstemperatur bis das angestrebte Konzentrat erreicht ist;
6. f) Einmischung des Konzentrats in das Grundöl aus dem Kessel über den Hauptkreislauf bis eine Zielmischung erreicht ist,
7. g) Rückführung der Anordnung auf Normaldruck ohne Sauerstoffzufuhr und Entgasung der Zielmischung im Kessel durch Applizierung eines geeigneten Grobvakuums.

The method according to the invention follows the steps:

1. a) Fill a boiler with base oil (this is done under atmospheric conditions and laboratory temperature) thereafter Schutzgasspülen a gas space of the boiler by alternately generating a rough vacuum by means of a suction device and filling the gas space with inert gas by means of a protective gas supply;
2. b) filling a liquefaction chamber shut off from a main circuit with a defined mass of a viscosity index improver, for example in the form of a polymer ball, and a defined mass of base oil corresponding to the composition of a desired concentrate under atmospheric conditions and laboratory temperature;
3. c) multiple Schutzgasspülen from a gas space of the liquefaction chamber by alternately generating a rough vacuum by means of a suction device and filling the gas space with inert gas by means of a protective gas supply;
4. d) subsequent filling of the gas space of the liquefaction chamber with inert gas up to a defined overpressure;
5. e) liquefying the viscosity index improver in the liquefaction chamber and simultaneously flushing with the introduced into the liquefaction chamber base oil in a continuous circulation of the base oil through a secondary circuit at a temperature above a solubility temperature until the desired concentrate is reached;
6. f) mixing the concentrate into the base oil from the boiler via the main circuit until a target mixture is reached,
7. g) return of the assembly to normal pressure without oxygen supply and degassing of the target mixture in the boiler by applying a suitable rough vacuum.

The dissolved concentrate (m ₁ ) consists of at least 70 wt% viscosity index improver and at most 30 wt% base oil.

What is essential is a combination of low-shear liquefaction by means of controlled, controllable heating of the substances and of a suitable protective gas, such as, for example, nitrogen or butane or carbon dioxide. The temperature is chosen between 90 ° C and 100 ° C and the defined overpressure in the liquefaction chamber is chosen between 100 mbar and 50 bar to prevent outgassing during the mixing of viscosity index improver in the base oil. For further embodiments, the overpressure is preferably chosen to be less than 24 bar, more preferably the overpressure is less than 10 bar. The defined overpressure prevents outgassing during the mixing of viscosity index improvers in base oil and minimizes the solubility time. The pressure in the boiler is less than or equal to half the pressure in the liquefaction chamber in this embodiment.

The arrangement according to the invention for carrying out the method for incorporating viscosity index improvers into base oils for the production of a target mixture consists of a boiler for a base oil and a liquefaction chamber for a viscosity index improver. For this purpose, a main circuit and a secondary circuit for a separate conditioning of mixing partners of the target mixture are arranged. The main circuit is arranged for filling and conditioning the base oil and the secondary circuit for liquefying and conditioning a concentrate of viscosity index improver and base oil.

For one embodiment, the main circuit connects the boiler, at least one pump, at least one heater, and a plurality of static mixers in series via a main line. The liquefaction chamber is connected via a branch line to the main circuit and via a secondary line to the secondary circuit, which leads via a pump back into the liquefaction chamber. A first suction device is connected to the liquefaction chamber and a second suction device to the boiler, wherein the Suction devices are operated via a common vacuum pump. A first protective gas supply is connected to the liquefaction chamber and a second protective gas supply to the boiler, wherein the protective gas feeds are connected to a common inert gas pressure vessel.

The first suction device of the liquefaction chamber is defined by the vacuum pump, a suction line, a three-way cock and a connection to the liquefaction chamber and the second suction device of the boiler is defined by the vacuum pump, another suction line, a three-way tap and a connection to the boiler.

The first protective gas supply to the liquefaction chamber via the protective gas pressure vessel, several line sections of a protective gas line, a metering valve, a three-way valve and a connection to the liquefaction chamber and the second inert gas supply of the boiler via the inert gas pressure vessel, several line sections of a protective gas line, a metering valve, a three-way cock and a connection to Boiler.

The pumps of the arrangement are low-shear rotary lobe pumps in this embodiment; other possible pumps are not excluded. The heater is in this embodiment a Einschraubheizkörper, with other heaters are conceivable.

For one embodiment, the main line in the boiler ends in a dive with freely rotatable tail. For a further embodiment, the main pipe in the boiler ends in a mixing nozzle.

The stub line below the liquefaction chamber opens into the main line and into a Venturi nozzle, which is located near the point of connection to the main line in the branch line.

In the liquefaction chamber, a melting grid is arranged, wherein the secondary line above it opens into the liquefaction chamber.

The main pipe, the secondary pipe, the sting pipe and the boiler are thermally insulated.

Due to the use of inert gases, in particular nitrogen, the solubility temperature for the mixture of viscosity index improvers with base oils is lowered. Thus, the output temperatures of the mixing partners can be reduced and saved about 50% to 60% of the electrical energy for the thermal conditioning of the substances. Under the conditions of inert gas at lower pressure and lower temperature, the otherwise observed outgassing of ethylene and propylene, which are components of VIV based on olefinic copolymers, are avoided, thus maintaining miscibility with base oil.

In addition to the improved solubility properties of VIV macromolecules, the use of shielding gases, including the conditioning of the base oil, avoids aging processes such as oxidation and hydrolysis in the mixing partners.

Embodiment of the invention

Figur 1

Löslichkeitstemperatur ϑ_L eines hochpastösen Viskositätsindex-Verbesserers auf Basis olefiner Copolymere in einem Grundöl in Abhängigkeit des Viskositätsindex-Verbesserer-Anteils der Mischung,

Figur 2

die erfindungsgemäße Vorrichtung zur Einmischung von Viskositätsindex-Verbesserern in geeignete Grundöle und

Figur 3

die erfindungsgemäße Vorrichtung zur Einmischung von Viskositätsindex-Verbesserern in geeignete Grundöle in einer weiteren Ausführungsform.

The invention will be explained in more detail with reference to an embodiment. Show this

FIG. 1

Solubility temperature θ _{L of} a high viscosity viscosity index improver based on olefinic copolymers in a base oil depending on the viscosity index improver content of Mixture,

FIG. 2

the inventive device for incorporation of viscosity index improvers in suitable base oils and

FIG. 3

the inventive device for incorporation of viscosity index improvers in suitable base oils in a further embodiment.

FIG. 1 shows a diagram in which the dependence of the solubility temperature θ _L of a mixture of x wt% of a viscosity index improver (OCP base) and 100 wt% on olefin based - x wt% of a base oil at varying VIV fraction under atmospheric conditions in Warming cabinet (course with circles and Strichpunktlinienzug) and under N ₂ atmosphere and with overpressure (with approx. 5 bar with star, with approx. 9 bar with diamond marked) is represented. When exceeding the solubility temperature θ _L under Duck- and inert gas conditions described is a homogeneous mixture.

Investigations were carried out in the laboratory for oven tests, in which mixtures between viscosity index improvers (VIV) based on OCP and base oil with 4 wt% VIV fraction to 70 wt% VIV fraction were prepared under normal pressure. Under atmospheric conditions, in the mixing process, proportions of outgassing of ethylene and propylene occurred in proportion to the VIV fraction, which in the olefinic copolymers of the VIV used should, however, just help to improve the miscibility with the base oil. The gas phase formed led to cooling of the liquid mixture, which resulted in an increase in viscosity and deterioration of the mixing conditions. The solubility temperature θ _L increased sharply with increasing VIV content in the mixture. For mixtures with 8 wt% VIV content, the solubility temperature θ _L was 145 ° C, for mixtures with a VIV fraction above 20 wt%, the solubility temperature θ _L was 185 ° C ( FIG. 1 , Gradient with circles and dash-dot line).

The arrangement according to the invention ( FIG. 2 ) for incorporation of viscosity index improvers into suitable base oils prevents these side effects. Another embodiment is shown in FIG FIG. 3 shown.

The low-shear, without participation of oxygen and moisture functioning mixing plant consists of a main circuit I and a secondary circuit II for the separate conditioning of the mixing partners.

The arrangement consists of a boiler 7, which can be opened under atmospheric conditions and is first filled with the base oil. In the main line 14 are for the circulation of the base oil, a pump 10, for example, a low-shear rotary lobe pump, and a heater 9, for example, a screw-in, arranged. In the main line 14 are at regular intervals static mixers 11, which support the mixing process. About the main line 14 of the main circuit I is led by the boiler 7 via the pump 10 back to the boiler 7. The main line 14 terminates in the boiler 7 in a dip tube 12 with freely rotatable tail to support the distribution of the incoming fluid into the boiler 7. The rotatably mounted end of the dip nozzle 12 is rotated by the inflow into the boiler 7 in rotation and realized a Spiral mixing of the mixture flowing from the main line with the liquid in the boiler 7. Via a sting line 16 is an interference of a dissolved concentrate m ₁ , at least 70 wt% viscosity index improver and at most 30 wt% base oil, from the secondary circuit II in the Base oil, which flows through the main line 14 of the main circuit I. A liquefaction chamber 1, which serves the liquefaction of VIV bales, is connected at its lower end via the stub line 16, in which a Venturi nozzle 6 is arranged, and via a shut-off and metering valve 5 to the main line 14. A secondary line 15 branches off below the liquefaction chamber 1 from the branch line 16 and leads over a further pump 4, which is also a rotary piston pump in this embodiment, back into the liquefaction chamber 1 above a melting grate 3, which is arranged in the liquefaction chamber 1. The sub-line 15 forms together with the branch line 16 the secondary circuit II (bordered with a dashed line). The arrows on main line 14, sub-line 15 and stub line 16, horizontal and vertical, indicate the flow direction of the fluids in main circuit I and secondary circuit II. All pipe sections and the boiler 7 are thermally insulated.

The liquefaction of VIV bales in the liquefaction chamber 1 takes place by heating on a melting grid 3. The melting grid 3 has a grid support with a triangular cross-section and serves for inhomogeneous temperature field generation, whereby the concentrate m _{1 is} heated to an average temperature T _m1 during the conditioning phase. In accordance with the concentrate m _{1 to be produced} in the conditioning phase, the melt grid 3, with the VIV bales applied, is constantly flushed with the introduced base oil. The pump 4 provides for a circulation of the liquid components in the liquefaction of the concentrate m ₁ in the secondary circuit II.

For protective gas purging and inert gas filling, the following system components are arranged accordingly. A vacuum pump 21, together with a suction line 22, a three-way valve 23 and a connection to the liquefaction chamber 1, a first suction device 2a of the liquefaction chamber 1. The second suction device 2b of the boiler 7 by the vacuum pump 21, a suction line 24, a three-way cock 25 and through a Connection to the boiler 7 defined. The first protective gas supply 8a of the liquefaction chamber 1 takes place via an inert gas pressure container 81, a protective gas line 821 and a protective gas line 823, a metering valve 822, the three-way valve 23 and the connection to the liquefaction chamber 1. The second protective gas supply 8b of the boiler 7 takes place via the protective gas pressure container 81, a Inert gas line 831 and a protective gas line 833, a metering valve 832, the three-way valve 25 and the connection to the boiler 7. The arrows, horizontal and vertical, indicate the flow direction of the protective gas in the suction and filling mode.

The liquefaction chamber 1 is thus connected to the shielding gas pressure vessel 81 via the suction device 2a and the protective gas supply 8a and the boiler 7 via the suction device 2b and protective gas supply 8b. The suction devices 2a, 2b and the protective gas supplies 8a, 8b are used in addition to the protective gas purging and protective gas filling the gas space of the liquefaction chamber 1 and the boiler 7 and the setting of a suitable, defined overpressure, the overpressure in the liquefaction chamber 1 is designated by p _m1 and the overpressure in the boiler 7 with p ₂ .

With the suction devices 2a, 2b and the protective gas supplies 8a, 8b, the pressure control of the mixing plant, which causes the lowering of the solubility temperature for concentrate m ₁ and target mixture m ₂ . Thermally induced aging processes are excluded and at the same time 50% to 60% thermal energy is saved compared to atmospherically operated mixing plants.

The shut-off and metering valve 5 of the secondary circuit II remains closed during filling and during the conditioning phase and is only opened during the mixing process between the concentrate m ₁ and the base oil in such a way that the partial flow of the concentrate m ₁ from the secondary circuit II to the main flow of the base oil from the main circuit I at most stoichiometrically, according to the target mixture m ₂ , is set.

In the branch line 16, a veturizing nozzle 6 is arranged near the connection point to the main line 14. With the Veturidüse 6 is for mixing the concentrate m ₁ from the secondary circuit II in the base oil, which flows through the main circuit I, at the point of Meeting the stitch line 16 with the main line 14 of the partial flow of the secondary circuit II sucked into the partial flow of the main circuit I.

In the main line 14 between the pump 10 and the connection point to the branch line 16 is a Einschraubheizkörper 9 is arranged for heating the base oil to an average temperature T ₂ of 60 ° C to 90 ° C during the conditioning phase.

In the branch line 16, between the liquefaction chamber 1 and the branch to the sub-line 15 is a sight glass and in the liquefaction chamber 1 itself, a sight glass is also arranged. Both sight glasses are used to control the Schlierenfreiheit of the concentrate m ₁ and the control of mass transfer from the liquefaction chamber. 1

FIG. 3 shows the inventive device for incorporation of viscosity index improvers in suitable base oils in another embodiment. Across from FIG. 2 the dip tube 12 is replaced by a mixing nozzle 13. The flowing from the main line 14 via the mixing nozzle 13 in the boiler 7 liquid simultaneously sucks through lateral openings of the mixing nozzle 13, according to the ejector principle, liquid from the boiler 7 in the mixing nozzle 13 and mixes both liquid streams in the mixing nozzle 13th to a liquid free jet, which emerges from the mixing nozzle 13 below the liquid level in the boiler 7.

Conditioning of the concentrate m ₁ in the secondary circuit II:

The liquefaction chamber 1 shut off from the main circuit I becomes at least 70 wt% viscosity index improver and at most 30 wt% base oil with a suitable mass of base oil and a suitable number of 25 kg bales of the viscosity index improver according to the composition of the desired concentrate ml (macromolecular copolymers) under atmospheric conditions and laboratory temperature equipped and sealed. First, a rough vacuum is generated in the gas space of the liquefaction chamber 1 via the suction device 2a. Then the gas space of the liquefaction chamber 1 is filled with inert gas via the protective gas supply 8a. This process of inert gas purging is repeated several times. This is followed by the filling of the gas space of the liquefaction chamber 1 with protective gas, up to a defined overpressure p _m1 . The overpressure p _m1 in the liquefaction chamber 1 can be between 100 mbar and 50 bar. For the exemplary embodiment, the overpressure p _{m1 is} preferably less than 24 bar, in which case it is less than 10 bar in the specific case. The deposited over the heated grate 3 VIV bales are flushed by the constant circulation of the introduced base oil on the pump 4 in the secondary circuit II. During the conditioning phase, more and more liquefied constituents dissolve out of the VIV bales until the batch is present as concentrate m ₁ at a temperature T _m1 above the solubility temperature (for example about 100 ° C. or 337 K at 9 bar overpressure). For visual control of the transport of a striae-free concentrate m ₁ from the liquefaction chamber 1, the built-in sight glasses made of borosilicate glass are provided.

Conditioning of the base oil in the main circuit I:

At the same time, a mass of base oil suitable for the target mixture m ₂ at room temperature is filled into the vessel 7. Above the gas space above it in the boiler 7, a coarse vacuum is also generated several times alternately by means of the suction device 2b and then filled with inert gas via the protective gas supply 8b. Following the protective gas purging, the gas space of the boiler 7 is filled with protective gas up to an overpressure p ₂ of p ₂ < p _m1 . Finally, the base oil is pumped by the pump 10 through the main circuit I and temperature controlled by a heater 9 to the temperature T ₂ (of approx. 90 ° C or 363 K). The base oil from the boiler 7 passes through the static mixer 11 introduced at regular intervals in the main line 14 of the main circuit I and finally reaches the boiler 7 via the dip tube 12.

While in the liquefaction chamber 1 of the secondary circuit II, the protective gas is used with an overpressure p _m1 , takes place in the boiler 7 of the main circuit II, the application of the inert gas with a lower pressure p ₂ . The static pressure difference p _m1- p _{2 is} distributed essentially as a fluid mechanical energy loss via the static mixer 11 mounted in the main circuit I at regular intervals. The static mixers 11 mounted in the main line 14 ensure a low-shear mixing of the fluid flow by generating swirl and transverse components in the velocity field. Shear-induced aging processes are avoided.

Mixing of the concentrate into the main stream of the base oil:

If both mixing partners (concentrate m ₁ in the liquefaction chamber 1 of the secondary circuit II and base oil in the boiler 7 of the main circuit I) are conditioned, the mixing process takes place. The shut-off and metering valve 5 of the liquefaction chamber 1 is opened, so that the partial flow of the concentrate is brought together in a suitable manner with the main flow of the base oil via the Venturi nozzle 6. In this case, the pressure p _m1 in the liquefaction chamber 1, the pressure p ₂ ( p _m1 > p ₂ ) in the boiler 7 and the delivery pressure p _{P of} the pump 10 in the main circuit I, before the confluence of the partial flows, are selected such that, on the one hand Outflow of the concentrate m ₁ is ensured from the liquefaction chamber 1, and on the other hand, the pressure difference p _m1 - p _{2 is} realized via the pressure drop of the total flow at a mixing temperature T _m via the static mixer 11. For locally lowering the static pressure of the partial flow from the Liquefaction chamber 1 and to produce a suction effect in the main flow, is coming from the secondary circuit II and projecting into the main circuit I, the Venturi nozzle 6 with bevelled end of the nozzle in the main flow direction.

nach Konditionierung und während des Mischungsvorgangs sei p _m1 ≈ p _P und mithin gilt V̇ _m1+V̇ ₂ =V̇ _m ;
daraus folgt für die Mischungstemperatur T _m, welche oberhalb der Löslichkeitstemperatur des VIV liegen muss: $$T_{\mathrm{m}}\cong \frac{{\rho }_{\mathrm{m}1}\left(T_{\mathrm{m}1}\right){\dot{V}}_{\mathrm{m}1}{c}_{p,{\mathrm{m}}_1}\left(T_{\mathrm{m}1}\right)}{{\rho }_{\mathrm{m}}\left(T_{\mathrm{m}}\right){\dot{V}}_{\mathrm{m}}{c}_{p,\mathrm{m}}\left(T_{\mathrm{m}}\right)}{T}_{\mathrm{m}1}+\frac{{\rho }_2\left(T_2\right){\dot{V}}_2{c}_{p,2}\left(T_2\right)}{{\rho }_{\mathrm{m}}\left(T_{\mathrm{m}}\right){\dot{V}}_{\mathrm{m}}{c}_{p,\mathrm{m}}\left(T_{\mathrm{m}}\right)}{T}_2$$

In order to quantify the mass flows Ṁ ₂ , Ṁ _m1, Ṁ _m from the main and secondary flow, the volume flows V̇ ₂ , V̇ _m are to be measured before and after the confluence. With the aid of the previously determined temperature-dependent densities and specific heat capacities of the mixing partners ρ ₂ ( T ₂ ) , ρ _m1 ( T m ₁ ), c _{p, 2} ( T ₂ ) , c _{p, m1} ( T _m1 ), in addition to the mass flows ( Ṁ _m1 = ρ ( T _m ) _m V̇ _m - ρ ( T ₂ ) ₂ V̇ ₂ ) as well as the enthalpy flows
Ḣ ₂ = ρ ₂ ( T ₂ ) V̇ ₂ c _{p, 2} ( T ₂ ) T ₂ , Ḣ _m1 = ρ _m1 ( T _m1 ) V̇ _m1 c _{p, m1} ( T _m1 ) T _m1 determinable. In this case, any heat flows between pipeline and liquids after the conditioning phase are neglected as loss terms by radiation. The mixture temperature can be estimated on the basis of the enthalpy flow balance before and after the mixing process: $${\dot{\mathrm{<figure-callout\; id="1"\; label="H\; ̇\; m"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">H\; </figure-callout>}}}_{\mathrm{m}}+{\dot{H}}_2={\dot{H}}_{\mathrm{m}}$$

after conditioning and during the mixing process let p _m1 ≈ p _P and therefore V̇ _m1 + V̇ ₂ = V̇ _m ;
from this follows for the mixing temperature T _m , which must be above the solubility temperature of the VIV: $$T_{\mathrm{m}}\cong \frac{{\rho }_{\mathrm{m}1}\left(T_{\mathrm{m}1}\right){\dot{V}}_{\mathrm{m}1}{c}_{p.{\mathrm{m}}_1}\left({\mathrm{<figure-callout\; id="1"\; label="T\; m"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">T\; </figure-callout>}}_{\mathrm{m}}\right)}{{\rho }_{\mathrm{m}}\left(T_{\mathrm{m}}\right){\dot{V}}_{\mathrm{m}}{c}_{p.\mathrm{m}}\left(T_{\mathrm{<figure-callout\; id="1"\; label="m\; T\; m"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">m\; </figure-callout>}},\right)}{T}_{\mathrm{m}}{\mathrm{}1}_{}+\frac{{\rho }_2\left(T_2\right){\dot{V}}_2{c}_{p.2}\left(T_2\right)}{{\rho }_{\mathrm{m}}\left(T_{\mathrm{m}}\right){\dot{V}}_{\mathrm{m}}{c}_{p.\mathrm{m}}\left(T_{\mathrm{m}}\right)}{T}_2$$

Return of the system to normal pressure and degassing of the target mixture m ₂ :

At the end of the mixing process, the target mixture m ₂ in the boiler 7 (respectively main line 14) under the overpressure p ₂ with p ₂ = p _m2 ≈ p _m1 and the mixture temperature T _m with T _m = T _m2 before. The system is carefully returned to normal pressure, but without Oxygen supply. Due to the significantly lower viscosity of the target mixture m ₂ at the mixture temperature T _m over the concentrate, the degassing of the additional inert gas succeeds within a very short time. In order to evaporate any excess ethylene or propylene molecule constituents which are no longer bound to the olefinic copolymers of the blended viscosity index improver, a rough vacuum can optionally be applied (eg p ₂ ≈-0.5 bar). For this purpose, the suction device 2b can be used.

Pressure reactor experiments in which the same mixing partners as in the atmospheric solubility were combined in the same mixing ratio, but under protective gas at overpressure and brought into solution, however, even at 70 wt% VIV share a solubility temperature θ _L of only about 100 ° C ( FIG. 1 , Stars and diamond) These pressure reactor experiments thus show an energy saving potential of at least 50% compared to conventional mixing plants with stirrers and shredders.

In the process of the invention, the mixing operations are carried out at a temperature (about 100 ° C) at which a further processing of the mixtures can follow immediately, without having to dissipate excess heat energy.

reference numeral

I

Main circuit

II

Secondary circuit

1

liquefaction chamber

2a

first suction device
21 vacuum pump
22 suction line
23 three-way stopcock

2 B

second suction device
24 suction line
25 three-way cock

3

melting grid

4

Pump in the sub-line 15

5

metering valve

6

venturi

7

boiler

8a

first protective gas supply
81 inert gas pressure vessel
821 inert gas line
822 dosing valve
823 inert gas line

8b

second inert gas supply
831 inert gas line
832 dosing valve
833 inert gas line

9

heater

10

Pump in the main line 14

11

mixer

12

dip pipe

13

mixing nozzle

14

Main line

15

Next line

16

Stitch line

θ _L

Solubility temperature of a mixture of a formulation of x wt% of a viscosity index improver component and of (100 wt% - x wt%) of a base oil with varying VIV content under atmospheric conditions in the heating cabinet

m ₁

Concentrate of at least 70 wt% viscosity index improver and at most 30 wt% base oil

m ₂

target mixture

T _m1

average temperature of the concentrate m ₁ during the conditioning phase

T _m2

Mixture temperature of the target mixture m ₂ in the boiler 7

T _m

Mixing temperature of the total flow

T ₂

mean temperature of the base oil

p _m1

Overpressure in the liquefaction chamber 1

p _m

Overpressure at the measuring point of the mixing temperature T _{m of} the total flow

p ₂

Overpressure in the boiler 7

p _P

Delivery pressure of the pump 10

Ṁ ₂

Mass flow from the boiler 7, in the main flow, between boiler and branch to the branch line 16

Ṁ _m

Total mass flow after the confluence of the partial flows from boiler 7 and liquefaction chamber 1

Ṁ _m1

Mass flow from the liquefaction chamber 1, via the branch line 16 into the main flow, with Ṁ _m1 = Ṁ _m - Ṁ ₂

V ₂

Volume flow from the boiler 7, in the main flow, between the boiler and branch to the branch line 16

V _m

Total volume flow after the confluence of the partial flows from boiler 7 and liquefaction chamber 1

V _m1

Volume flow from the liquefaction chamber 1, via the branch line 16 into the main flow , with V̇ _m1 = V̇ _m - V̇ ₂

H ₂

Enthalpy flow from the boiler 7, in the main stream, between the boiler and branch to the branch line 16

H _m1

Enthalpy flow from the liquefaction chamber 1, via the branch line 16 into the main flow

Claims (15)

Method for incorporating viscosity index improvers (VIV) into base oils in an assembly for mixing viscosity index improvers in base oils, comprising the steps of: a) filling a boiler (7) with base oil and multiple Schutzgasspülen a gas space of the boiler (7) by alternately generating a rough vacuum by means of a suction device (2b) and filling the gas space with inert gas by means of a protective gas supply (8b); b) filling a liquefaction chamber (1) shut off from a main circuit (I) with a defined mass of a viscosity index improver and a defined mass of base oil corresponding to the composition of a desired concentrate (m ₁ ) under atmospheric conditions and laboratory temperature; c) multiple Schutzgasspülen from a gas space of the liquefaction chamber (1) by alternately generating a rough vacuum by means of a suction device (2a) and filling the gas space with inert gas by means of a protective gas supply (8a); d) subsequent filling of the gas space of the liquefaction chamber (1) with inert gas up to a defined overpressure ( p _m1 ); e) liquefying the viscosity index improver in the liquefaction chamber (1) and simultaneous flushing with the introduced into the liquefaction chamber (1) base oil in a continuous circulation of the base oil over a secondary circuit (II) at a temperature ( T _m1 ) above a solubility temperature until desired concentrate (m ₁ ) is reached; f) mixing the concentrate (m ₁ ) into the base oil from the boiler (7) via the main circuit (I) until a target mixture (m ₂ ) is reached, g) return of the assembly to normal pressure without oxygen supply and degassing of the target mixture (m ₂ ) in the boiler (7) by applying a suitable rough vacuum. A method according to claim 1, characterized in that
the dissolved concentrate (m ₁ ) consists of at least 70 wt% viscosity index improver and at most 30 wt% base oil. A method according to claim 1, characterized in that
as protective gas nitrogen or butane or carbon dioxide is used. A method according to claim 1, characterized in that
the temperature ( T _m1 ) of the concentrate in the liquefaction chamber is below 120 ° C and that the overpressure ( p _m1 ) in the liquefaction chamber (1) is between 100 mbar and 50 bar, preferably less than 24 bar, even more preferably less than 10 bar, that the temperature ( T _m2 ) of the target mixture in the boiler is less than 100 ° C and that the overpressure ( p ₂ ) in the boiler is p ₂ <= p _m1 / 2. Arrangement for carrying out the method for incorporation of viscosity index improvers into base oils consisting of a boiler (7) for a base oil and a liquefaction chamber (1) for a viscosity index improver for producing a target mixture (m ₂ ), characterized in that
a main circuit (I) and a secondary circuit (II) for separate conditioning of mixing partners of the target mixture (m ₂ ) is arranged. Arrangement according to claim 5, characterized in that
the main circuit (I) is arranged for a filling and conditioning of the base oil and the secondary circuit (II) for a liquefaction and conditioning of a concentrate (m ₁ ) of viscosity index improver and base oil. Arrangement according to claim 5 or 6, characterized
that the main circuit (I) the boiler (7) via a main line (14), in which at least one pump (10), at least one heater (9) and a plurality of static mixers (11) are arranged, connects to itself, that the liquefaction chamber (1) via a branch line (16) with the main circuit (I) and via a secondary line (15) with the secondary circuit (II), which via a pump (4) leads back into the liquefaction chamber (1) is connected, and
that a first suction device (2a) with the condensing chamber (1) and a second suction device (2b) with the boiler (7) are connected, wherein the suction devices (2a, 2b) via a common vacuum pump (21) are operated, and
in that a first protective gas feed (8a) is connected to the liquefaction chamber (1) and a second protective gas feed (8b) is connected to the boiler (7), the protective gas feeds (8a, 8b) being connected to a common protective gas pressure container (81). Arrangement according to claim 7, characterized in that
the first suction device (2a) of the liquefaction chamber (1) by the vacuum pump (21), a suction line (22), a three-way cock (23) and a connection to the liquefaction chamber (1) and
the second suction device (2b) of the boiler (7) is defined by the vacuum pump (21), a suction pipe (24), a three-way cock (25) and a connection to the boiler (7). Arrangement according to claim 7, characterized in that
the first protective gas supply (8a) of the liquefaction chamber (1) via the inert gas pressure vessel (81), a protective gas line (821) and a protective gas line (823), a metering valve (822), a three-way cock (23) and a connection to the liquefaction chamber (1) and
the second protective gas supply (8b) of the boiler (7) via the protective gas pressure vessel (81), a protective gas line (831) and a protective gas line (833), a metering valve (832), a three-way cock (25) and a connection to the boiler (7) , Arrangement according to one of the preceding claims 7 to 9, characterized in that
the pumps (4; 10) are low-shear rotary lobe pumps. Arrangement according to one of the preceding claims 7 to 9, characterized in that
the heater (9) is a screw-in heater. Arrangement according to one of the preceding claims 7 to 9, characterized in that
the main line (14) in the boiler (7) ends in a dip tube (12) with freely rotatable end piece or in a mixing nozzle (13). Arrangement according to one of the preceding claims 7 to 9, characterized in that
the stub line (16) below the liquefaction chamber (1) opens into the main line (14) and that a Venturi nozzle (6) is arranged near the connection point to the main line (14) in the stub line (16). Arrangement according to one of the preceding claims 7 to 13, characterized in that
in the liquefaction chamber (1) a melting grid (3) is arranged and the secondary line (15) above it in the liquefaction chamber (1) opens. Arrangement according to one of the preceding claims 7 to 14, characterized in that
the main pipe (14), the secondary pipe (15) and the sting pipe (16) and the boiler (7) are thermally insulated.

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