DE3334277T1 - Apparatus and method for continuously producing aqueous polymer solutions - Google Patents

Description

The invention relates to an apparatus and a method for producing aqueous polymer solutions, and in particular to one Apparatus and method for the continuous on-site manufacture of such solutions for use in US Pat secondary and tertiary extraction of oil from underground, oil-bearing formations.

Apparatus and methods for continuously polymerizing water soluble polymers are the subject of a number of US patents. For example, US Pat. No. 2,820,777 discloses a continuous process for polymerizing and hydrolyzing acrylamide. The patent contains no reference to an apparatus for performing this method. U.S. Patent 3,732,193 discloses a continuous polymerization process in which an aqueous solution of a water-soluble unsaturated monomer, such as acrylamide, is polymerized on a heated moving belt to form a polymer in the form of a dry, thin film. U.S. Patent 4,110,521 discloses an apparatus for the continuous polymerization of water soluble Polymeric. The apparatus comprises a jacketed tubular reactor with static mixers and a jacketed reactor The wide reactor also has static mixers and a dilution arrangement containing the static mixers for mixing of the polymer and the supplied water. A jacketed tank is used to hold back the implementation participants, which are added to the second reactor. According to this patent, the final product from the dilution device can be bulk stored or used directly will.

The apparatus described in US Pat. No. 3,732,193 is useful for all practical purposes in preparing aqueous polymer solutions of the kind used locally in secondary and tertiary oil extraction from underground, oil-bearing formations useless. The device disclosed in US Pat. No. 4,110,521, although obvious over the apparatus disclosed in US Pat. No. 3,732,193 Advantages for preparing aqueous polymer solutions for use in secondary and tertiary

Oil production has a number of disadvantages and will therefore for the on-site production of such solutions not applied. In particular, this device is characterized by their intensive use of static mixers. Static mixers are expensive and their use in the patent provided scope makes the device too expensive. In addition, the device of this patent requires temperature control arrangements not only in every reactor, but also in every tank or vessel that is used for the reactants will. The uses of cooling or heating devices increased in size and type as suggested in the patent the complexity and cost of the device. Another important disadvantage of the device, which is not referred to in the patent Reference is made to the properties of the polymer solutions produced in the device. Although this patent includes as one of its objects the provision of an apparatus in which the reaction conditions can be subjected to the formation of polymers with uniform molecular weight and uniform molecular weight distribution discloses the same no arrangement for preparing polymer solutions in a manner that prevents degradation of the polymer containing the solutions or reduced to a low level. The degradation or dilution of the polymer adversely affects the indentation and mobility properties of the polymer solution, thereby reducing its Ability to meet the requirements of oil-bearing formations is particularly adversely affected.

The device according to the invention and the method are unique for the continuous production of aqueous polymer solutions laid out on site, especially aqueous, partially hydrolyzed Polyacrylamide solutions for use as propellants and / or mobility buffers in secondary or tertiary extraction of oil from underground, oil-bearing formations or reservoirs. The device is cheap too and easy to install and use. Furthermore, the same enables the formation of polymer solutions under closely controlling all stages of manufacture, resulting in an end product with predictable properties

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its ability to meet the requirements of practically all oil-bearing formations or reservoirs. The inventive The device is further characterized by the fact that there are no pumps for handling concentrated polymer solutions are required and that - where they are used - the pumps advantageously only on the inlet side of the device are provided for the feed stream.

According to a preferred embodiment of the invention, the device has a polymerization reactor, a hydrolysis reactor and a thinner. The polymerization and hydrolyzing reactors are preferably in the form of a elongated hose or pipe with a length and cross-sectional area such that the residence time of the reaction mixture in the hose or tube with a predetermined The flow rate is sufficient to complete the reaction in the hose or pipe. The dimensions the reactors can preferably be scaled to optimum size by incorporating liquid flow controls or delay arrangements in the reactors so as to reduce the flow rate of the reaction mixtures in a manner to reduce that a> iCompletion of the intended implementations is ensured. The thinner used in the device is characterized in that it is a thinner the polymer solution in such a way that the solution, such as a partially hydrolyzed polyacrylamide solution, a predetermined concentration without any adverse effects on the integrity of the polymer containing the solution results.

An embodiment of the invention is shown in the drawings and is described in more detail below. It shows

Fig. 1 is a schematic view of an embodiment according to the invention the device;

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Figure 2 is a schematic cross-sectional view showing embodiments of the liquid flow control or delay assembly in the reactor shows and

3, 4 and 5 are schematic cross-sectional views at right angles with respect to the view of FIG.

The embodiment of the device shown in FIG. 1 has a polymerization reactor 10, a hydrolysis reactor 12 and a thinner 14. The reactors 10 and 14 and the diluent 14 are preferably made of hoses or tubes made of stainless steel and each is provided with an inlet and an outlet. The ends of reactors 10 and 12 are advantageously rounded or cap-shaped in order to improve the flow pattern of the entering and exiting liquids. The dimensions of reactors 10 and 12 and the diluent 14 vary and, in the case of reactors 10 and 12, are determined by the residence time, a preselected flow rate, Desired completion of the reaction taking place in the reactors, and in the case of the diluent 14 by the residence time determined at a preselected flow rate so as to obtain a polymer solution of the desired concentration. So indicates, for example, when using the device for the continuous production of a dilute aqueous solution of a partially hydrolyzed polyacrylamide, the polymerization reactor 10 advantageously has a length to diameter ratio from about 6i 1 to about 10: 1 during the hydrolysis reactor 12 preferably has a length to diameter ratio of about 4: 1 to about 6: 1. The thinner 14 can on the other hand, have a length to diameter ratio of about 30: 1 to about 10: 1.

As indicated above, the dimensions, in particular the volume of the reactors 10 and 12 can be adjusted to an optimal capacity can be reduced by providing flow control or delay arrangements in the reactors. Such arrangements can

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Have sieves that are practically perpendicular to the flow of liquids are present in the reactors, as well as plates parallel to the flow, plates in the form of a grid parallel to the flow or bars parallel to the river. Figures 2 to 5 show an arrangement that has a plurality of plates 16 in the form of a Has grid 18 in the .Reaktor 10. More than one grid can be applied as shown, and the grids can be used in the There are spacing ratios from each other and each grille or grate can be at a different angle with respect to the other Lattice oriented in the reactor. By this spacing the grid and rotating the same so that the Plates of each grid are in different planes with respect to the plates of the other grid, a more uniform one becomes Overall flow pattern preserved. In those cases where there is a need to control the temperature of the reaction mixture in the reactors It is desirable to use coils for both heating and cooling the conversion mixture in place of the towing arrangements are built into the reactors, we

The diluent 14 of the device, as shown in Figure 1, is expediently provided inside with a plurality of dispersing stations 14a for the polymer solution. The stations can be perforated Have plates or screens or a combination of perforated plates and screens. One as thinner 14 a suitable unit is described in pending U.S. patent application (Serial No. 279,027). The thinner 14 is unique, since it is used to achieve a dilution of the polymer solutions, such as aqueous solutions or partially hydrolyzed polyacrylamide serves without any noticeable degradation or dilution of the polymer, whereby the production of an end product with indentation and mobility properties is enabled that meet the requirements correspond to an oil-bearing formation or reservoir.

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With particular reference to Figure 1, that is in the drawing Device shown in particular for the continuous production of polymer solutions for use in the secondary and tertiary oil extraction on site. At the end of the stream tanks and auxiliary equipment are provided for reactors 10 and 12, which are necessary for the production of a polymer solution, which are necessary for pressing into a borehole of an oil-bearing Formation or reservoir are suitable. As shown, a water tank 20 is connected to a water source, and a storage tank is for keeping a supply ■ of an aqueous solution of a monomer, such as acrylamide, provided. Before withdrawing the monomer solution from the tank 22 into the water stream, the monomer solution can be through a Ion exchanger 24 are guided in order to remove metallic ions, such as copper, which could intervene in the polymerization reaction. The water flow itself can be passed through a heater 26 to raise the temperature of the water sufficiently so that the To facilitate the start of the polymerization reaction. After the monomer solution is added to the viasser stream from the water source it is conveniently passed through a static mixer 28 for thorough distribution of the monomer solution to achieve in the conversion mixture. The aqueous monomer solution is fed from the mixer 28 to an oxygen stripper 30. It is in communication with a nitrogen gas source 32. Nitrogen gas is bubbled through the monomer solution in stripper 30 to remove dissolved oxygen from the solution.

As shown, the monomer solution is upon exiting the scraper 30 a first catalyst from the tank 34 is added. The catalyst can be selected from a number of organic and inorganic compounds be selected as they are used in the polymerization of monomers. Mixtures of such catalysts can be used are applied and they can be added separately, as shown in Figure 1. The monomer solution can be in the presence of the first catalyst in a! your tank or a large diameter pipe 36 for a short period of time. The monomer-catalyst solution is then made up the tank 36 and a second catalyst from the tank

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added. In the embodiment of the device shown are Pumps 40, 44 and 44, 46 are assigned to the water tank 20, the storage tank 22 for the monomer and the catalyst tanks 34 and 38. After the addition of the second catalyst, the monomer solution can then be passed through a static mixer 48 together with the catalysts and fed into the polymerization reactor 10.

The residence time of the reaction mixture in the reactor 10 can vary from about 7 to about 10 hours and then the resulting polymer solution is discharged from reactor 10 and to a point brought, where a hydrolyzing agent from a storage tank 50 by means of a pump 52 is incorporated into the polymer solution. The reaction mixture thus formed is then advantageously passed through a static mixer 54, from where it is fed to a Hydrolysis reactor 12 is performed.

The residence time of the reaction mixture in the reactor 12 can vary to about 4 to about 6 hours, whereafter the hydrolyzed polymer solution is fed to the diluent 14. Water out a source will hydrolyze the diluent 14 along with that Polymer solution fed from the reactor 12. The diluted solution exits the diluent and enters a static mixer 56 where additional water is introduced from a source. The diluted solution exits the mixer 56 and can directly be guided to an inlet bore or the same can be fed to a storage level, v / o it further before use is diluted.

In order to explain the specific application of the apparatus for preparing a dilute aqueous solution of a partially hydrolyzed Polyacrylamide becomes a monomer solution containing 50% by weight of acrylamide through an ion exchanger at one speed at about 313.8 g / min, to remove any copper ions from the solution. The solution is then in a Introduced to a temperature of about 4 3 ° C heated water stream. The heated solution is passed through a static mixer and then through an oxygen stripper in which it is purged of any dissolved oxygen by means of nitrogen gas will. When the purified solution comes out of the peeler,

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a 25 wt.% ige solution of sodium bisulfite in the solution is weighed in at a rate of about 0.11 g / min. The catalyzed solution is then introduced into a small (22 L) holding tank where it remains for 15 minutes. If the Solution leaking from the tank becomes a 25% strength by weight aqueous Ammonium persulfate solution into the monomer solution at one rate of about 0.23 g / min. The monomer-catalyst solution is then passed through the static mixer and a polymerization reactor at a rate of about 4.60 kg / min, and a temperature of 41 ° <i and under a pressure at 7 bar. The reactor is about 3 m long and has has a diameter of 0.7 m and has a capacity of approximately 1417.5 1. The polymerization of the monomer extends in the Reactor over a period of about 9 hours. The polymer solution is subjected to a temperature increase of about 57 ° C. Which resulting 6% by weight polyacrylamide solution formed in the reactor leaves the reactor at a rate of 4.60 kg / min under a pressure of 6.3 bar. It becomes a 50% strength by weight Aqueous solution of sodium hydroxide by means of a pump into the polymer solution at a rate of about 50 g / min, and introduced under a pressure of 6.3 bar. The temperature of the hydroxide solution is about 24 ° C, the caustic polymer solution is first passed through a static mixer and then into a hydrolysis reactor. The reactor is about 3.1 m long and has a diameter of about 0.7 m and still has a capacity of 888.3 1.

The polymer is allowed to hydrolyze in the reactor for a period of time of 6 hours. The percentage hydrolysis in the reactor is approximately 30%. The concentration The partially hydrolyzed polyacrylamide in the solution amounts to about 6.6% by weight. The hydrolyzed polymer solution has a temperature of about 57 ° C. The solution is then at a rate of 4.6 3 kg / min, and a pressure of 5.4 bar fed to a sieve thinner, which has a pipe -r \ it iron diameter of about 10.1 and a length of about 3.1 m.

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The diluent preferably has six polymer dispersing stations, each of which has screens of different particle sizes, the particle size of the screens progressively decreasing from the inlet end of the diluent to the outlet end thereof. It is supplied to water having a temperature of about 21 ⁰ C at a rate of about "2'4,7O kg / min under a pressure of 5.3 bar the diluent simultaneously with the hydrolyzed polymer solution. The solution is further in the diluent diluted to give a solution with about 1% by weight of partially hydrolyzed polyacrylamide. The residence time of the solution in the diluent is about 2 minutes. ;. 4 kg and fed under a pressure of 1.4 bar and a temperature of about 27 ° C to a point where water at a temperature of about 21 C into the solution at a rate of 135 kg / min under a pressure of The solution to which the water has been added is then passed through a static mixer to obtain a 0.1% solution of the partially hydrolyzed polyacrylamide, thus making the diluted solution suitable for injection into a borehole or as mobility p To be used as a buffer or as a propellant.

Claims (22)

Device and method for the continuous production of aqueous polymer solutions Patent claims 1. Apparatus for preparing dilute solutions more water-soluble A polymer, characterized by an arrangement for providing a reaction mixture forming polymer which has at least one monomer; a conversion device having an inlet end for receiving the conversion mixture and a Outlet end for discharging the polymer solution formed from the reaction mixture, the reaction device having a length and Has cross-sectional area, such that the residence time of the Qmsetzlösung in the conversion arrangement at a predetermined The flow rate is sufficient to cause virtually complete polymerization of at least one of the monomers Achieve the flow rate controlling arrangement associated with the conversion arrangement for the purpose of controlling the flow rate of the reaction mixture from the egg eel to the outlet of the reaction vessel, the reaction mixture being in the reaction device a period of time is retained which is sufficient for at least one monomer to be substantially completely consumed polymerize. 2. Device according to claim 1, characterized in that that the reaction vessel is cylindrical and the ratio the length of the reaction vessel to its diameter is from about 6: 1 to about 10: 1. 3. Device according to claim 1, characterized in that that the outlet of the reaction vessel is in communication with a second reaction vessel, the second reaction vessel having a Having an inlet at one end and an outlet at the other end and characterized in that it has a length and a cross-sectional area such that the residence time of the polymer solution in the second reaction vessel with a continuous The flow rate is sufficient to modify the polymer solution from the first conversion vessel. 4. Apparatus according to claim 3, characterized in that that the second reaction vessel is cylindrical and the ratio of length to diameter is from about 4: 1 to about 6: 1. 5. Apparatus according to claim 1, characterized in that the conversion vessel with a flow-retarding arrangement is provided to control the flow of the reaction mixture in the reaction vessel. 5. Apparatus according to claim 5, characterized in that the flow-delaying arrangement is one formed from plates Has grid, wherein the plates are transverse to the direction of flow of the conversion mixture in the conversion vessel. 7. Apparatus according to claim 5, characterized in that that the flow retarding device comprises at least two grids formed from plates, the grids in the spaced relationship are arranged from each other, and the plates at least one grid present in a plane different from that in which the plates have the other grid. 8. Apparatus according to claim 5, characterized in that that the flow retarding device comprises a plurality of hollow tubes, the longitudinal axis of which is practically parallel is aligned with the longitudinal axis of the conversion vessel. 9. Device according to claim 8, characterized in that the hollow tubes contain a liquid for heating or cooling the Have reaction mixture in the reaction vessel. tt> 10. The device according to claim 3, characterized in that the second reaction vessel in connection with the arrangement that dissolves the polymer solution, this solution arrangement has a plurality of polymer dispersing stations has, which are in the distance ratio to each other along a horizontal Axis are present in the solution arrangement. 11. The device according to claim 10, characterized in that the stations dissolving the polymer are sieves which have a particle size such that the surface of the polymer passes through the sieves as it passes through is enlarged. 12. The device according to claim 1, characterized in that an ion exchanger for removing troublesome Metal ions of which the reaction mixture forming the polymer is present. 13. The device according to claim 1, characterized in that an arrangement for removal is released Oxygen from the conversion mixture is provided. 14. The device according to claim 3, characterized in that a second reaction vessel with a Flow retardation arrangement Zuiti controlling the flow rate of the polymer solution by means of the same is provided. 15. Device for the continuous production of dilute solutions from water-soluble polymers, characterized by a closed system which includes an arrangement for providing a reaction mixture which forms the polymer containing at least one polymerizable monomer; a first conversion vessel in communication with the assembly for receiving the reaction mixture, the first reaction vessel has a length and a cross-sectional area of this type possesses that the residence time of the reaction mixture therein is sufficient at a predetermined flow rate, - 4 - . 7th in order to completely polymerize at least one monomer, a second reaction vessel with the first reaction vessel in For the purpose of modifying the reaction product from the first reaction vessel, there is a connection to the second reaction vessel has a length and cross-sectional area such that the residence time of the reaction mixture therein is sufficient to the reaction product from the first reaction vessel in a to modify in a predetermined manner an arrangement for introducing a chemical reaction agent into the reaction product from the first reaction vessel for the purpose of modifying the same is present, as well as a dilution arrangement in connection with the second reaction vessel for the purpose of incorporating a predetermined Amount of a diluent is provided in the reaction product from the second reaction vessel. 16. The device according to claim 15, characterized that the first and second reaction vessels have flow retardation arrangements are provided in order to increase the residence time of the reaction mixtures in the reaction vessels. 17. The device according to claim 15, characterized in that that the dilution assembly has first and second dilution devices the first dilution device comprises an elongated cylindrical part with a chamber, in which a plurality of dispersing stations in spaced relationship are arranged, at least one of these stations Sieves with a predetermined one. Particle size, the second dilution device downstream of the first dilution device is present and serves to add additional diluent in the diluted reaction product from the first dilution device to disperse. 18. A method for the continuous production of dilute solutions of water-soluble polymers, characterized in that a the in a closed system Polymer-forming reaction mixture is present, the at least contains a polymerizable monomer, the reaction mixture -y - introduced into the first reaction vessel at a predetermined flow rate and in the same for a period of time sufficient to effect the polymerization of the polymer in the reaction mixture, a chemical Modifying agent is introduced into the reaction product from the first reaction vessel and the resulting reaction mixture is fed at a predetermined flow rate into the second reaction vessel, the resulting The reaction mixture is kept in the second reaction vessel until the reaction product from the first reaction vessel passes through the chemical modifier has been modified, the modified reaction product from the second reaction vessel a dilution device is fed, which with a multi-t number of dispersing stations is equipped, as well as the modified one Reaction product is passed through each of the dispersing stations of the dilution device at a predetermined flow rate in order to dilute the modified Implementation product to accomplish. 19. The method according to claim 18, characterized e t that the reaction mixture forming the polymer contains acrylamide. 20. The method according to claim 18, characterized in that the residence time of the reaction mixture in the first reaction vessel is from about 7 to about 12 hours. 21. The method according to claim 18, characterized in that g e k e η η -. It is noted that the residence time of the reaction mixture in the second reaction vessel is from about 4 to about 6 hours. 22. The method according to claim 19, characterized in that that an alkali metal hydroxide is used as a chemical modifier, which can hydrolyze the polymer formed in the first reaction vessel, as well as the hydroxide is present in an amount sufficient to effect 25 to about 45 percent hydrolysis of the polymer. 2 & «. Method according to claim 18, characterized in that that the reaction mixture forming the polymer is passed through a mixer before it enters the first reaction vessel reached and the reaction product from the first reaction vessel premixed before entering the second reaction vessel will.