DE19917156A1 - Production of water-in-oil fuel emulsions, especially for use in internal combustion engines, comprises splitting a water stream into separate lamellae and introducing the lamellae into a diesel oil stream - Google Patents

Abstract

Process (I) for producing an emulsion of water in diesel oil for use as a fuel, comprises splitting a liquid water stream into separate fluid lamellae with a thickness of less than 100 mu m and introducing the lamellae into a diesel oil stream so that the lamellae fragment into droplets. Independent claims are also included for the following: (1) use of process (I) to produce a fuel emulsion using a liquid other than water, the liquid being immiscible with diesel oil; (2) use of process (I) to produce a fuel emulsion using a liquid fuel other than diesel oil.

Description

The invention relates to a method for producing a water-in-diesel oil Emulsion as a fuel and uses of this process.

The use of water-in-diesel emulsions as fuel Lowering the combustion temperature and thus reducing the soot and nitrogen oxide content in the exhaust gas is known. It is also known that the rapid evaporation of water droplets in the combustion chamber into one Increasing the surface area of the diesel oil droplets and thus increasing them performance. Such water-in-diesel oil emulsions exhibit finest water droplets in a continuous phase in diesel oil. Systems that are as finely dispersed as possible are desired, i. H. one if possible narrow size distribution of the water droplets.

Different methods of production are used in the prior art of such emulsions. This is how an injection of water into a rotationally symmetrical swirl chamber in DE 44 08 392 A1, DE 44 14 488 C1 and EP 0 392 545 A1. DE 43 41 038 A1 describes the Proposed use of an emulsion turbine. These procedures require however a supply of at least the water with high pressure and / or moving parts that are subject to wear.

The object of the invention is to provide a method for manufacturing a water-in-diesel emulsion as a fuel that is not constructive complex devices, in particular no moving parts, with a rapid change in the composition of the emulsion and a narrow water droplet size distribution can be achieved. Furthermore it is Object of the invention to show uses of the method.  

The task is solved in that in the first step a water Liquid flow in spatially separated water-fluid lamellae of one width <100 µm is split. Then these water-fluid fins passed into at least one diesel oil liquid stream, one Fragmentation of the water-fluid lamella takes place in water droplets.

When splitting the water-liquid flow there are no moving ones Parts required. Miniaturized static, for example, are suitable for this Mixers with capillary-like channels with a width of <100 µm, as they do for example in V. Hessel, et al., Gas / Liquid Dispersion Processes in Micromixers: The Nexagonal Flow, in Process Miniaturization: 2nd International Conference on Microreacfion Technology, New Orleans, 1998 and W. Ehrfeld et al., Potential applications of chemical and biological microreactors, in Yearbook 1997 - Process engineering and chemical engineering, VDI-GVC 1997 are described. Using such miniaturized mixers also stable framed emulsions especially made of silicone oil with water or a aqueous dye solution are generated (V. Hessel, et al., multiphases processes in microreactors - concept, systems and characterization, in Chemical engineer technology 1998, 9, 1074 and W. Ehrfeld, et al., Microreactors - a challenge for chemical and chemical engineering Biotechnology, in GIT Labor-Fachzeitschrift 1998, 4, 346-350). Here was exploited the principle of multilamination, in which the fluid flows in each case a large number of partial streams are split up and the alternating be arranged side by side. The use of the principle of Multilamination or miniaturized static mixers for production fuel emulsions, in particular water-in-diesel oil emulsions, is not known, however.

In the known experiments with micromixers, water-silicone oil Emulsions in volume ratios from 1: 1 to 35: 1 are precisely characterized. The reason for the limitation to volume ratios was greater than 1: 1 in that with an excess of silicone oil compared to water none  desired finely dispersed systems were obtained. Rather you got Silicone oil droplets with an undesirably very wide size distribution, which in a continuous phase of water. In all of these experiments was not a finely dispersed system of water droplets in a continuous Preserve silicone oil phase.

In addition, the experiments for the production of silicone oil Water emulsions under static conditions. A quick change in the The composition of the emulsions obtained was not sought.

Based on this experimental experience, one would Transfer to a system of water and diesel oil an emulsion of Diesel oil droplets can be expected in a continuous water phase been, which has a very wide size distribution. That would be it Use of micromixers for the production of fuels Water-in-diesel emulsions have been completely unsuitable.

From this it was now completely unexpected and completely surprising with known ones Micromixers an emulsion of water droplets in a continuous Phase of diesel oil even with a volume ratio of water to diesel oil received less than 1: 1. In addition, the emulsion obtained proved to be finely dispersed, d. H. it was in contrast to the silicone oil-water systems get a much narrower size distribution. Beyond that are shown that with such micromixers a rapid change of Emulsion composition can be achieved with water-in-diesel oil emulsions can what with an application in the field of internal combustion engines changing load is required.

To clog capillary-like channels in miniaturized static Avoiding mixers, it can be advantageous to use a pre-cleaned, for example to use filtered diesel oil. Here it can also from Be advantageous to temper the emulsifying device, especially at  Outside temperatures below 0 ° C, for example to prevent flocculation Prevent constituents of the diesel oil.

Using the method according to the invention, water-in-diesel oil Simple emulsions, d. H. without complex devices and without moving Parts. The process can thus be in the immediate vicinity of Place of use, for example an internal combustion engine or one Oil burner. For this it is of great advantage that the composition of the emulsion by this method rapidly, i. H. without any significant time delay, to those in the respective load state optimal composition can be adjusted. This is simply the Volume flow of the water-liquid flow in relation to the diesel oil Adjust liquid flow. Therefore, this procedure is also required no pre-storage in which the emulsion before combustion is cached.

According to a preferred variant, the diesel oil liquid flow is also provided the introduction of the water-fluid lamellae into fluid lamellae of a width <1 mm split, each with a water-fluid lamella each with at least a diesel oil fluid lamella is brought together. this makes possible For example, a targeted merging of individual water and diesel oil Fluid fins. So it can be advantageous to have a water-fluid lamella each and at least one diesel oil fluid lamella in a common channel conduct. A partial water-in-diesel oil emulsion stream is formed in each case. The partial emulsion streams are combined to form an emulsion stream.

Several water-fluid lamellae and several diesel oil Fluid lamellae passed together in such a way that one at a time Water fluid lamella adjacent to at least one diesel oil fluid lamella in exits this room. The fluid lamellae can be checkered like this staggered in the room so that each water Fluid lamella is surrounded by, for example, four diesel oil fluid lamellae and  vice versa. The resulting emulsion is continuously removed from the room derived. Suitable miniaturized mixers are, for example, in EP 0 758 918 B1 for carrying out chemical reactions.

The direction of flow of a water-fluid lamella can essentially rectified with or opposite to the flow direction of the diesel oil Liquid flow or the Dieselöl-Fluidlamelle, in which or Water-fluid lamella is passed. However, it is also conceivable to use a water Fluid lamella at an angle of 0 ° to 180 ° to the diesel oil liquid flow or to the Dieselöl-Fluidlamelle.

If the flow directions are essentially opposite to each other, so the resulting water-in-diesel oil emulsion stream is preferred in derived substantially perpendicular to the two flow directions. Therefor Particularly suitable micromixers are described, for example, in: V. Hessel et al., Potentials and Realization of Microreactors, Proc. of boarding school. Symposiom of Microsystems, Intelligent Materials and Robots, Sendai, Japan, Sept. 1995 and V. Hessel, et al., Characterization of mixing in micromixers by a test reaction: Single mixing units and mixer arrays, Industrial and Engineering Chemistry Research 1999, (38) 3, 1075-1082.

Widths of the diesel oil fluid lamellae <500 μm are preferred, preferably <100 µm. The smaller the widths of the diesel oil fluid fins, the narrower the water-fluid lamellae can be adjacent, each spaced apart by at least one diesel oil fluid lamella. This enables a large one while maintaining small water droplet sizes To achieve volume ratio of water to diesel oil.

A water-in-diesel oil emulsion is preferably obtained by the process, which have an average size of the water droplets in the range from 0.1 μm to 50 μm, particularly preferably in the range from 0.5 μm to 15 μm. Such Emulsions advantageously have a standard deviation of  Water droplet sizes of <10 µm, in particular <5 µm. Especially the standard deviation is advantageously less than or equal to the mean size the water droplets in µm.

The width of the water-fluid lamellae is preferred for such emulsions <50 µm, particularly preferably <10 µm.

While the smallest possible width of the water-fluid lamellae is preferred, a preferred height of the water and / or diesel oil fluid fins is greater equal to the width of the water or diesel oil fluid lamellae, particularly preferred <250 µm. Due to the greater height compared to the width, the im essentially the same droplet size distribution, a larger material throughput be achieved.

That is for the production of water-in-diesel oil emulsions as fuel Volume ratio of water-liquid flow to diesel oil Liquid flow according to the water-to-diesel to be achieved Ratio. The range from 1: 1000 to 1: 1 is preferred. particularly preferably in the range from 1: 500 to 1: 3.

The fragmentation and thus the droplet size distribution can be determined by the Choice of the total volume flow and the volume flows of the diesel oil and Water-liquid flow can be influenced in a targeted manner. To achieve a uniform fragmentation becomes the volume flow of a water-fluid lamella preferably in the range from 150 to 0.1 ml / h, particularly preferably in the range from 75 to 15 ml / h.

The emulsion is preferably produced in a temperature range of 0 ° C to 100 ° C, particularly preferably from 0 ° C to 60 ° C. The pressure of the water or / and diesel oil liquid flow is preferably in the range from 0 to 30 bar, particularly preferably from 1 to 15 bar.  

The fragmentation of the water-fluid lamella into water droplets can be caused by different methods are supported.

According to one method, mechanical vibrations are used, in particular Ultrasound applied. The general idea in an emulsifying device for emulsifying hydrocarbons with water DE 195 44 554 A1 uses ultrasonic waves for combustion purposes known, but no information on the constructive design of the Contains device or to carry out the method.

So the entire device in which the water liquid flow with the Diesel fluid flow is brought together using ultrasound be charged.

According to a process variant, at least areas of the diesel oil Liquid flow, the water-fluid lamellae and / or the diesel oil Fluid blades or / and the water-in-diesel oil emulsion mechanically Vibration applied. The part of a Micro-mixer vibrated, in which the formation of the Fluid lamellae takes place and / or in which the water-fluid lamellae with the Diesel oil-liquid flow or the Dieselöl-Fluidlamellen brought together become.

The mechanical deflection preferably takes place as a periodic deflection parallel or perpendicular to the flow direction of the fluid lamella of the water or / and the diesel oil.

The frequency of the mechanical vibrations is given Flow rate of water-liquid flow and / or diesel oil Liquid flow selected in view of the particle size to be achieved. This is possible in that the mechanical vibration of the  The process of fragmentation is initiated. This will, on the one hand for a given oscillation frequency a narrow distribution of the Water droplet sizes achieved, on the other hand with increasing or Lowering the oscillation frequency the maximum of the droplet sizes distribution can be shifted towards smaller or larger values. This is of particular advantage in the rapid adjustment of the emulsion to the changing requirements for internal combustion engines.

Mechanical vibrations in the frequency range from 1 kHz to are preferred 100 kHz, particularly preferably in the range from 10 kHz to 50 kHz.

A second method is the fragmentation of the water-fluid lamellae supported by the application of an electrical field. This can for example to the area receiving the emulsion stream as Electrode opposite the area forming the fluid lamellae A voltage can be applied to the counter electrode. Here are known Techniques for the electrostatic atomization of liquids can be used (H. Wiggers and P. Walzel, Chemical Engineer Technology 1997, (69) 8, 1066-1073.

According to a third method, the fragmentation is carried out by introducing a gas supported. For this purpose, the gas can flow through the water-fluid flow, the diesel oil Fluid flow, the corresponding fluid lamellae and / or the water-in Diesel oil emulsion are supplied. In the simplest case, the gas if necessary, cleaned air. The water dispersion thus obtained, Diesel oil and gas can be used as fuel. However, it is also possible to separate the gas at least partially beforehand. To the Supply of a gas, i.e. for the production of gas-liquid dispersions can known miniaturized static mixers and known methods can be used (V. Hessel, et al., Gas / Liquid Dispersion Processes in Micromixers: The Hexagonal Flow, in Process Miniaturization: 2nd International Conference on Microreaction Technology, 1998, New Orleans).  

However, a gas can flow within the water or / and diesel oil Liquid flow are generated in that in the area of the mixer Temperature is increased so that a volatile component of the Liquid flows begin to boil and with it gas bubbles in the liquid be generated. It is also conceivable that a liquid flow is easy volatile liquid, for example a short chain hydrocarbon, to add. The admixed liquid or its gas can be used as Part of the fuel contributes to the combustion. However, it can also act as an inert substance, for example after generation the emulsion is separated.

To stabilize the emulsion to be produced, it can be advantageous to Water or diesel oil liquid flow at least one the emulsion add stabilizing substance. This is preferably Volume ratio of emulsifier to emulsion up to 1:10, particularly preferred 1: 5000 to 1: 20. Suitable emulsifiers are, for example, polyethylene oxides and their derivatives, for example monoethers, polyethylene propylene Copolymers, naphthenic acid and its salts, fatty acids and their salts, Fatty alcohols, alkyl sulfates, alkyl sulfonates, alkyl sulfites or combinations thereof.

At temperatures below 0 ° C there is a risk that a supply of Water is prevented by crystal formation. It can be an advantage the water-liquid flow at least one the crystallization temperature add water-reducing substance. Suitable substances are for example monohydric or polyhydric alcohols, such as methanol, ethanol or Ethylene glycol.

Furthermore, it can be advantageous to add water or / and diesel oil. Liquid flow at least one improving the fuel properties Add substance such as additives against deposits.  

After use, the process according to the invention is used for the production an emulsion as a fuel from diesel oil and one not with diesel oil miscible liquid or liquid mixture used. This will take place a water-liquid flow, a liquid flow or not with Diesel oil miscible liquid or liquid mixture, for example one or more mono- or polyhydric alcohols, such as ethanol or butanol, used.

After a further use, the method according to the invention is used for Production of an emulsion used as a fuel, instead of diesel oil one or more other liquid fuels, for example Hydrocarbons such as gasoline, kerosene, petroleum ether, liquid gas, aliphatic or aromatic nitro compounds can be used.

The method is particularly advantageous in the area of Fuel supply device of an internal combustion engine, for example a motor vehicle diesel engine used. The water-to-diesel oil Volume ratio can be, for example, using a electronic control, with regard to the current load and / or Emission values of the internal combustion engine can be set.

Variants of the method according to the invention are described below with the aid of schematic drawings explained in more detail. Show it:

Fig. 1 the known principle of splitting of two fluid streams into fluid lamellae,

Fig. 2 shows the principle of splitting a fluid flow into fluid lamellae and merging with a fluid stream,

Fig. 3 shows the housing base, the mixing element and the housing cover of a known micromixer separated from each other, in a perspective view

FIG. 4a the Micromixer of Fig. 3 cut by the plane of the inlets and the outlet,

FIG. 4b shows a the element performing with split section of Fig. 4a,

Fig. 5 the transition from parallel fluid lamellae about fragmenting fluid lamellae to fluid droplets after the micromixer according to Fig. 3,

FIG. 6a is a micromixer with longitudinally movable to the gap and coupled to an ultrasonic transducer mixing element cut from the side,

Fig. 6b the micromixer according to Fig. 6a with the housing cover removed, in plan view,

Fig. 6c the transition from parallel fluid lamellae about fragmenting fluid lamellae to fluid droplets after the micro-mixer of FIG. 6a,

Fig. 7a is a micromixer with movable transversely to the slot and coupled to an ultrasonic transducer mixing element cut from the side,

Fig. 7b the micromixer according to Fig. 7a with the housing cover removed, in plan view,

Fig. 7c the transition from parallel fluid lamellae about fragmenting fluid lamellae to fluid droplets after the micromixer according to Fig. 7a,

Fig. 8 is a micromixer with electrodes to support fragmentation cut from the side,

FIG. 9 diagram of the water droplet size distribution in diesel oil obtained with the micromixer according to FIG. 3.

In Fig. 1 is a known principle for splitting two fluid streams 2 , 4 of the fluids A, B in fluid lamellae 3 a, 3 b ,. . . or 5 a, 5 b ,. . . shown. For this purpose, a region of the supply 16 of the fluid A in channels 19 a, 19 b, is in a mixing element 12 . . . divided to form fluid lamellae. An opposite area of the feed 17 of the fluid B is also in channels 20 a, 20 b ,. . . divided to form fluid lamellae, the channels 20 a, 20 b ,. . . between the channels 19 a, 19 b ,. . . are arranged and together form a so-called interdigital structure 13 . A further element, not shown here, is arranged above the interdigital structure 13 of the mixing element 12 and covers all areas of the mixing element 12 except for a gap 22 lying above the interdigital structure 13 , indicated here by dashed lines. The slats 3 a, 3 b ,. . ., 5 a, 5 b ,. . . the fluids A and B flow adjacent to one another through the gap into an overlying mixing region, not shown here.

In the known silicone oil-water system, it was found that the Silicone oil fluid fins when merging with the water fluid fins Silicone oil droplets fragment and an emulsion of silicone oil droplets in a continuous water phase is obtained. These were emulsions with volume ratios of water to diesel oil greater than 1: 1 finely dispersed, with smaller volume ratios, however, with a very broad distribution of the Sizes of silicone oil droplets.  

Contrary to these known experiences, new experiments resulted Water-diesel oil systems surprisingly finely dispersed emulsions of Water droplets in a continuous diesel oil phase, especially at the volume ratios of water desired for fuels Diesel oil less than 1: 1.

According to another variant of the method, only the water-liquid flow is split into fluid lamellae and this is introduced into a diesel oil fluid flow, whereby the individual water-fluid lamellae are fragmented in water droplets. Three corresponding elements 41 , 42 , 51 of a micromixer are schematically separated from one another in FIG. 2 and shown in perspective. In the mixing element 42 there is a feed 46 for the water-liquid flow, which is fed to the element 42 from below through a bore, not shown here. The feed 46 is in the right area in channels 49 a, 49 b ,. . . divided to form fluid lamellae. On this element 42 , an element 51 is arranged with a gap 52 such that the gap 52 extends over a region of the channels 49 a, 49 b ,. . . extends. An element 41 with a feed 47 for the diesel oil fluid flow, a mixing area 48 and a discharge 43 is arranged on the element 51 in such a way that the mixing area 48 is located above the gap 52 . For the sake of clarity, the elements 41 , 42 , 51 are not shown on top of each other, but separately from one another. The feed 47 and the mixing area 48 are designed as recesses passing through the element 41 . Only through the arrangement of the element 41 on the element 51 and through a cover plate (not shown here), which has openings for the supply and discharge and which is to be arranged on the element 41 , are chamber-like channels formed from the feed region 47 and the mixing region 48 . To achieve a through all channels 49 a, 49 b ,. . . Microchannels of sufficient pressure loss and a gap 52 must be provided in the same flow. To unite the channels 49 a, 49 b ,. . . To avoid generated water-fluid lamellae, the element 51 with the gap 52 is made as thin as possible, for example as a slotted film. It is also conceivable to use one instead of one across all channels 49 a, 49 b. . . running column 52 to provide individual columns such that these each exactly over a channel 49 a, 49 b ,. . . come to rest and cover the adjacent land areas. The element 51 can also be an integral part of the element 41 .

A known micromixer 1 , which operates according to the principle explained in relation to FIG. 1, is shown in FIG. 3, three parts, the housing base 10 a, the mixing element 12 and the housing cover 10 b, being shown in perspective separately for the sake of clarity.

The mixing element 12 has two feeds 16 and 17 and an interdigital structure 13 arranged between the two for forming fluid lamellae. The mixing element 12 can be inserted into a corresponding recess 11 in the housing base 10 a. The housing cover 10 b has two inlets 14 , 15 which merge into bores for supply and discharge 16 , 17 , which are opposite the corresponding supply and discharge 16 , 17 of the mixing element 12 . In the bottom of the housing cover 10 b, an element 21 is arranged with a gap 22 such that the gap 22 comes to lie over the interdigital structure 13 of the mixing element 12 . In the housing cover 10 b and above the gap 22 and connected thereto a dashed line, indicated here mixing region 18 is arranged, in which the fragmentation of the water-fluid lamellae to water droplets in a held diesel oil phase. The mixing area 18 merges into an outlet 23 , likewise indicated by dashed lines, which is connected to the outlet 24 . For sealing to the housing bottom 10 a, an annular groove 27 is incorporated in the bottom of the housing cover 10 b for receiving an O-ring seal. To position the housing cover 10 b and bottom 10 a to each other, the housing base 10 a has two dowel pins 28 a on its top, which fit into corresponding bores 28 b in the underside of the housing cover 10 b. By means of four screws, not shown here, the housing cover 10 b can be braced against the housing base 10 a, for which purpose four threaded holes 29 are provided in the base 10 a and corresponding four through holes 30 are provided in the housing cover 10 b.

In FIG. 4a the micromixer 1 according to FIG. 3 is shown cut through the plane covering the inlets 14 , 15 and the outlet 24 . For a better overview, details and a dashed line of the cut surfaces have been omitted. In contrast to FIG. 3, the housing cover 10 b and the housing base 10 a are shown connected to one another with the mixing element 12 inserted. FIG. 4b shows a section that includes the gap 22 and the subsequent mixing region 18 .

The formation of water droplets 6 a, 6 b ,. . . in a continuous diesel oil phase 7 is shown schematically simplified in the three drawings of FIG. 5. Immediately behind the shown in the previous figures gap and in the mixing area are water-fluid lamellae 3 a, 3 b ,. . . in a diesel oil liquid flow before, here also in the form of fluid lamellae 5 a, 5 b ,. . .. In a process called fragmentation, 3 a, 3 b,. . ., 5 a, 5 b ,. . . Areas with a varying thickness in the direction of flow, which is shown in the middle drawing. This process is finally concluded in the formation of water droplets 6 a, 6 b ,. . . in a continuous diesel oil phase 7 (upper drawing).

The process of fragmentation can be specifically supported by the use of mechanical vibrations, such as ultrasound. Micromixers suitable for this purpose and the associated fragmentation processes are shown in FIGS. 6a-c and 7a-c.

In Fig. 6a, a micromixer 60 is cut by a mechanical vibrator in the form of an ultrasonic sensor 65 shown from the side. The cutting plane runs perpendicular to the cutting plane shown in FIG. 4a and runs through the outlet 64 and parallel through the gap 63 . The mixing element 62 is movably arranged in a recess 61 of the housing base 60 a, the possible direction of movement being indicated by the double arrow. The mixing element 62 is connected via a pin 66 to the ultrasound transmitter 65 , which is only indicated schematically here, the pin being guided through a through opening 67 through the housing base 60 a. Except for the features associated with the mobility of the mixing element 62 , this micromixer 60 has the same structure as the micromixer 1 shown above.

The micromixer 60 is shown in Fig. 6b b with housing cover removed 60 in plan view from above. The interdigital structure 68 can be seen in the mixing element 62 for forming the fluid lamellae. The mixing element 62 is connected to the ultrasound transmitter 65 via the pin 66 and arranged in the recess 61 in such a way that the mixing element 62 can be moved perpendicularly to the flow direction of the fluid lamellae predetermined by the interdigital structure 68 and thus parallel to the alignment of the gap 63 .

How the formation of water droplets 72 a, 72 b ,. . . in a continuous diesel oil phase 73 in such a micro-mixer 60 is shown in simplified form in the two drawings of FIG. 6c. Due to the periodic movement of the mixing element 62 , the fluid lamellae of the water 70 a, 70 b,. . . and the diesel oil 71 a, 71 b ,. . . not straight, but wavy. The process of fragmentation is already specifically determined by this wave-shaped course, ie by the regular displacement of the fluid lamellae relative to one another. Water droplets 72 a, 72 b, are finally formed from the slats laterally displaced relative to one another. . . in a continuous diesel oil phase 73 .

Another micro-mixer 80 with movable mixing element 62 is shown in section in FIG. 7a from the side. The sectional plane runs perpendicular to the sectional plane shown in FIG. 6a and both through the two inlets 81 and 82 and perpendicular to the gap 63 . For easier comparison, the same reference numerals as in FIGS. 6a-c have been used in FIGS. 7a-c for elements with the same function. As can also be seen from FIG. 7 b, in which the micro-mixer 80 is shown in a top view with the housing cover removed, the mixing element 62 is arranged in a recess 61 in the housing base 60 a so as to be movable parallel to the flow direction of the fluid lamellae predetermined by the interdigital structure 68 and correspondingly connected to an ultrasound transmitter 65 via a pin 66 . The pin 66 is guided in a through opening in the housing base 60 a. The mixing element 62 can therefore be subjected to a periodic movement parallel to the direction of flow and thus perpendicular to the alignment of the gap 63 .

The process of fragmentation into water droplets 72 a, 72 b ,. . . is shown schematically simplified in the two drawings of FIG. 7c. The movement of the mixing element 62 takes place parallel to the direction of flow of the fluid lamellae, ie the interdigital structure 68 is periodically moved back and forth below the gap 63 in the direction of the supply of the water and the diesel oil. Due to the pressure prevailing in the channels of the interdigital structure 68 pressure difference of the mixing element 62 in the direction of water supply, in the deflection of a larger volume flow of water fluid lamellae 70 a, 70 b ,. . . and when deflecting in the direction of the diesel oil supply, a larger volume flow of diesel oil fluid lamella 71 a, 71 b ,. . . passed through gap 63 . The resulting shape of the fluid lamellae is shown in the lower drawing in FIG. 7c. The fragmentation which is deliberately predetermined by constricting areas of the fluid lamellae leads to the formation of water droplets 72 a, 72 b ,. . . in a diesel oil phase 73 .

The invention furthermore micromixer 90, wherein the fragmentation of the water-fluid lamellae is assisted by applying an electric field, Fig. 8 shows in section from the side. This micromixer 90 has the same structure as the micromixer 1 according to FIGS. 3, 4a and 4b. The mixing element 93 and the outlet 94 , here highlighted by cross-hatching, are connected to a voltage source 96 via electrical leads 95 a, 95 b. The mixing element 93 is electrically insulated from the housing cover 92 and the housing base 91 and the outlet 94 to the housing cover 92 . By applying a sufficiently high voltage difference between the outlet 94 and the mixing element 93 , which depends both on the geometry of the micromixer and on the fluids used, the fragmentation can be specifically supported. In particular, small droplet sizes can be achieved with this.

Embodiment

Water-in-diesel oil emulsions were produced by the method according to the invention using the micromixer 1 shown in FIG. 3. In the interdigital structure 13 of the mixing element 12 , the 18 channels 19 a, 19 b,. . ., 20 a, 20 b ,. . . a width of 25 µm and a depth of 300 µm. The element 21 arranged above the interdigital structure 13 had a gap with a width of 60 μm and a length of 2 mm. The volume flow of the diesel oil liquid flow was kept constant at 600 ml / h. The volume flow of the water-liquid flow was adjusted to the values listed in the following table.

The emulsions were at a temperature of 22 ° C and without the Made using an emulsifier.

With the mixing ratio 1:20, an average water droplet size of about 5 µm was achieved with a standard deviation of 2.5 µm, ie 68.3% of the droplets had a size in the range of 5 µm ± 2.5 µm. FIG. 9 shows the size distribution of the water droplets in the diesel oil phase obtained for this example and determined with a light microscope. The maximum is a droplet diameter of 5 µm. About 90% of the water droplets have a diameter in the range from 1 µm to 8 µm.

Reference list

1

Micromixer

2nd

Water-liquid flow

3rd

a,

3rd

b,. . . Water-fluid lamella

4th

Diesel fluid flow

5

a,

5

b,. . . Diesel fluid lamella

6

a,

6

b,. . . Water droplets

7

continuous phase diesel oil

10th

a case back

10th

b Housing cover

11

Recess

12th

Mixing element

13

Interdigital structure

14

Inlet for water-liquid flow

15

Diesel fluid flow inlet

16

Inlet for water-liquid flow

17th

Inlet for diesel oil liquid flow

18th

Mixing area

19th

a,

19th

b,. . . Channel for water-fluid lamella

20th

a,

20th

b,. . . Channel for diesel oil fluid lamella

21

Element with gap

22

gap

23

Exhaustion

24th

Outlet

27

O-ring groove

28

a dowel pin

28

b hole

29

Threaded hole

30th

drilling

41

Element with mixing area

42

Mixing element

43

Exhaustion

46

Inlet for water-liquid flow

47

Inlet for diesel oil liquid flow

48

Mixing area

49

a,

49

b,. . . Channels for water-fluid lamellas

51

Element with gap

52

gap

60

Micromixer

60

a case back

60

b Housing cover

61

Recess

62

Mixing element

63

gap

64

Outlet

65

Ultrasound transmitter

66

pen

67

Through opening

68

Interdigital structure

70

a,

70

b,. . . Water-fluid lamella

71

a,

71

b,. . . Diesel fluid lamella

72

a,

72

b,. . . Water droplets

73

continuous diesel oil phase

80

Micromixer

81

Inlet for water-liquid flow

82

Diesel fluid flow inlet

90

Micromixer

91

Case back

92

Housing cover

93

Mixing element

94

Outlet

95

a,

95

b,. . . electrical leads

96

Voltage source

Claims (19)

1. A process for producing a water-in-diesel oil emulsion as a fuel, comprising the following steps:

• a) splitting a water-liquid flow into spatially separated water-fluid lamellae with a width of <100 µm,
• b) directing the water-fluid lamellae into at least one diesel oil-liquid stream, the water-fluid lamellae being fragmented in water droplets.

2. The method according to claim 1, characterized in that before Introducing the water-fluid fins into the diesel-oil flow Fluid lamellae of a width <1 mm is split, one each Water-fluid lamella with at least one diesel oil fluid lamella is merged. 3. The method according to claim 2, characterized in that several Water-fluid lamellae and several diesel oil-fluid lamellae be led together into a room that one water Fluid lamella adjacent to at least one diesel oil fluid lamella in exits this room. 4. The method according to any one of the preceding claims, characterized characterized in that the width of the water-fluid lamellae <50 µm, preferably <10 microns.   5. The method according to any one of the preceding claims, characterized characterized in that the width of the diesel oil fluid lamella is <500 µm, preferably <100 microns. 6. The method according to any one of the preceding claims, characterized characterized in that the amount of water or / and diesel oil Fluid lamellae greater than or equal to the width of the corresponding fluid lamellae, preferably <250 microns. 7. The method according to any one of the preceding claims, characterized characterized in that the volume ratio of the water Liquid flow to diesel oil liquid flow in the range of 1: 1000 to 1: 1, preferably from 1: 500 to 1: 3. 8. The method according to any one of the preceding claims, characterized characterized in that the water-fluid lamella has a volume flow in Range from 150 to 0.1 ml / h, preferably from 75 to 15 ml / h, having. 9. The method according to any one of the preceding claims, characterized characterized in that the fragmentation of the water-fluid lamellae in Water droplets through the use of mechanical vibrations is supported.   10. The method according to claim 9, characterized in that the Fragmentation is supported by mechanical vibrations in such a way that at least areas of the diesel oil liquid flow and / or the Water-fluid lamellae and / or the Dieselöl-Fluidlamellen or / and the Water-in-diesel emulsion subjected to mechanical vibrations become. 11. The method according to claim 9 or 10, characterized in that the mechanical vibration takes place in such a way that a periodic Deflection parallel or perpendicular to the flow direction of the water Fluid lamellae and / or the Dieselöl-Fluidlamellen is effected. 12. The method according to any one of claims 9 to 11, characterized in that the frequency of the mechanical vibrations at a given Flow rate of the water-liquid flow and / or Diesel fluid flow in terms of the size to be achieved Water droplet is chosen. 13. The method according to any one of claims 9 to 12, characterized by mechanical vibrations in the frequency range from 1 kHz to 100 kHz, preferably from 10 kHz to 50 kHz. 14. The method according to any one of the preceding claims, characterized characterized in that the fragmentation of the water-fluid lamellae Application of an electrical field is supported.   15. The method according to any one of the preceding claims, characterized characterized in that the fragmentation of the water-fluid lamellae a gas in the water-liquid stream in which diesel oil Liquid flow, in the corresponding fluid lamellae and / or in the Water-in-diesel emulsion is supported by the fact that the gas initiated and / or a low-boiling, the gas when evaporating forming liquid is used above its boiling point. 16. The method according to any one of the preceding claims, characterized characterized in that the water or / and diesel oil liquid flow at least one stabilizing the emulsion, the fuel properties improving or / and the crystallization temperature of the water reducing substance is added. 17. Use of the method according to one of claims 1 to 16 for Production of an emulsion as a fuel, using a instead of water another liquid or liquid mixture, the is not miscible with diesel oil. 18. Use of the method according to one of claims 1 to 17 for Production of an emulsion as a fuel, using instead of diesel oil or several other liquid fuels can be used. 19. Use of the method according to one of claims 1 to 18 in Area of the fuel supply device of an internal combustion engine.