DE19917156B4 - Process for the preparation of a water-in-diesel oil emulsion as fuel and its uses - Google Patents

Abstract

Process for the preparation of a water-in-diesel oil emulsion as a fuel, comprising the following steps:
a) splitting a water-liquid stream into spatially separated water-fluid lamellae of width <100 μm,
b) directing the water-fluid lamellae into at least one diesel oil liquid stream, whereby fragmentation of the water-fluid lamellae into water droplets takes place.

Description

The The invention relates to a process for the preparation of a water-in-diesel oil emulsion as fuel and Uses of this method.

The Use of water-in-diesel emulsions as a fuel to reduce the combustion temperature and thus to reduce the soot and nitrogen oxide content in the exhaust is known. Furthermore, it is known that the rapid evaporation of water droplets in the combustion chamber to increase the surface of the Diesel droplets and thus an increase the specific performance leads. Such water-in-diesel emulsions have the finest water droplets in a continuous phase in diesel oil. Desired are possible fine dispersed systems, d. H. the smallest possible size distribution the water droplet.

In the prior art, various methods for producing such emulsions are mentioned. Thus, an injection of water into a rotationally symmetric vortex chamber in the DE 44 08 392 A1 . DE 44 14 488 C1 as well as the EP 0 392 545 A1 described. In the DE 43 41 038 A1 the use of an emulsion turbine is proposed. However, these methods require feeding at least the high pressure water and / or moving parts subject to wear.

task The invention is the provision of a method for the production a water-in-diesel emulsion as a fuel that does not require any structurally complex devices, In particular, no moving parts, needs, with a quick change the composition of the emulsion and a narrow water droplet size distribution can be achieved. Furthermore, it is an object of the invention uses of the procedure.

The Task is solved by that in the first step a water-liquid flow in spatial separated water-fluid slats of a width <100 microns is split. Then be these water-fluid fins in at least one diesel oil fluid stream directed, wherein a fragmentation of the water-fluid lamellae takes place in water droplets.

at the splitting of the water-liquid stream No moving parts are required. For this example, are suitable miniaturized static mixers with capillary channels of a Width <100 μm, like her for example in V. Hessel, et al., Gas / Liquid Dispersion Processes in Micromixers: The Hexagonal Flow, in Process Miniaturization: 2nd International Conference on Microreaction Technology, New Orleans, 1998 and W. Ehrfeld et al., application potentials of chemical and biological Microreactors, in Yearbook 1997 - Process Engineering and Chemical Engineering, VDI-GVC 1997 described. By means of such miniaturized Mixers were also able to get stable framed emulsions specially made from silicone oil with water or an aqueous dye solution Hessel, et al., Multiphase Processes in Microreactors - Concept, Systems and Characterization, in Chemie Ingenieur Technik 1998, 9, 1074 and W. Ehrfeld, et al., Microreactors - A Challenge for the Process engineering in chemistry and biotechnology, in GIT Labor-Fachzeitschrift 1998, 4, 346-350). Here, the principle of multilamination was exploited, in the the fluid streams each split into a plurality of sub-streams and which are arranged alternately next to each other. The use of the Principle of multilamination or of miniaturized static mixers for the production of fuel emulsions, in particular of water-in-diesel oil emulsions, is not known.

In In the known experiments with micromixers, water-silicone oil emulsions were prepared in volume ratios from 1: 1 to 35: 1 exactly characterized. The reason for the restriction volume ratios greater than 1: 1 was that at an excess of silicone oil in comparison no desired water finely dispersed systems were obtained. Rather, silicone oil droplets were obtained one very undesirable wide size distribution, which were in a continuous phase of water. In all In these experiments no finely dispersed system of water droplets was observed a continuous silicone oil phase receive.

In addition, the experiments for the preparation of silicone oil-water emulsions under static conditions. A rapid change in the composition of the resulting emulsions did not sought.

outgoing from this experimental experience would be at a transmission On a system of water and diesel an emulsion of diesel droplets in a continuous water phase has been expected, the one very wide size distribution having. That would be the use of micromixers for the production of fuel suitable water-in-diesel emulsions completely unsuitable.

From this It was now completely unexpected and completely surprising, with known micromixers an emulsion of water droplets in a continuous phase of diesel oil even at a volume ratio of Water to diesel oil of less than 1: 1. In addition, the preserved Emulsion as finely dispersed, d. H. it was in contrast to the silicone oil-water systems a much narrower size distribution receive. About that In addition, it has been shown that with such micromixers a rapid change of the emulsion composition in water-in-diesel emulsions can be achieved, which is a use in the field of internal combustion engines with changing load is required.

Around a clogging of capillary-like channels in miniaturized static To avoid mixers, it may be beneficial to have a pre-cleaned, For example, to use filtered diesel oil. Here can it may also be advantageous to temper the emulsifier, especially at outdoor temperatures from below 0 ° C, for example, to prevent flocculation of components of the diesel oil.

through the method according to the invention can Water-in-diesel emulsions easy, d. H. without elaborate devices and without moving parts obtained become. The method can thus be in close proximity to the place of use, For example, an internal combustion engine or an oil burner used become. Therefor it is still of great importance Advantage that the Composition of the emulsion by this method quickly, d. H. with no significant time delay to which in the respective Load state optimal composition can be adjusted. This is simply the volume flow of the water-liquid flow in relation to Diesel-liquid flow adjust. Therefore, there is no need for this method Vorspeichers in which the emulsion cached prior to combustion becomes.

To A preferred variant is also the diesel oil liquid stream before the introduction the water-fluid lamella split into fluid lamella width <1 mm, wherein in each case a water-fluid lamella each having at least one Diesel oil fluid lamella together becomes. this makes possible For example, a specific merging of individual water and Diesel oil fluid lamellae. So It may be advantageous, in each case a water-fluid blade as well at least one diesel oil fluid blade to lead into a common channel. Here, in each case a water-in-diesel oil emulsion partial stream educated. The emulsion partial streams are combined to form an emulsion stream.

Advantageously, a plurality of water-fluid lamellae and a plurality of diesel oil-fluid lamellae are jointly conducted into a space such that in each case a water-fluid lamella emerges adjacent to at least one diesel oil-fluid lamella in this space. The fluid fins can be routed to each other in a checkered manner in the space such that each water-fluid fin is surrounded by, for example, four diesel oil-fluid fins and vice versa. The resulting emulsion is continuously drained from the room. For this purpose, suitable miniaturized mixer, for example, in the EP 0 758 918 B1 described for carrying out chemical reactions.

The flow direction a water-fluid blade may be substantially rectified with or opposite to the flow direction of the diesel oil fluid stream or the diesel oil-fluid lamella be, in which or the water-fluid lamella is passed. It However, it is also conceivable, a water-fluid blade at an angle of 0 ° to 180 ° the diesel oil liquid stream or the diesel oil-fluid lamella be forwarded.

are the flow directions essentially opposite one another, the resulting Water-in-oil emulsion diesel power preferably substantially perpendicular to the two flow directions derived. Therefor Particularly suitable micromixers are described, for example in: V. Hessel et al., Potentials and Realization of Microreactors, Proc. of boarding school. Symposium 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.

Preferably, widths of the diesel oil-fluid lamella <500 microns, preferably <100 microns. The smaller the Widths of the diesel oil-fluid fins, the closer the water-fluid fins, each spaced by at least one diesel oil-fluid lamella, can be introduced. This makes it possible to achieve a large volume ratio of water to diesel oil while maintaining small water droplet sizes.

Prefers is obtained by the method, a water-in-diesel emulsion containing a mean size of water droplets in the Range of 0.1 μm up to 50 μm, particularly preferably in the range of 0.5 .mu.m to 15 .mu.m. Such emulsions advantageously have a standard deviation of the water droplet sizes <10 .mu.m, in particular <5 .mu.m. Especially is advantageous the standard deviation is less than or equal to the mean size of the water droplets in μm.

For such Emulsions, the width of the water-fluid lamellae is preferably <50 microns, especially preferably <10 μm, chosen.

While one preferably small width of the water-fluid blades is preferred is a preferred height the water or / and diesel oil fluid fins greater or equal the width of the water or diesel oil fluid fins, especially preferably> 250 μm. by virtue of which can be larger in height compared to the width at substantially the same droplet size distribution a larger substance throughput be achieved.

to Generation of water-in-diesel emulsions as fuel is the volume ratio of the water-liquid flow to the diesel oil fluid stream according to the water-to-diesel ratio to be achieved adjust. Preferably, the range is from 1: 1000 to 1: 1, more preferably in the range of 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 specifically influenced become. To achieve a uniform fragmentation of the Volume flow one Water-fluid lamella preferably in the range of 150 to 0.1 ml / h, especially preferably in the range of 75 to 15 ml / h.

The Preparation of the emulsion is preferably carried out in a temperature range from 0 ° C up to 100 ° C, more preferably from 0 ° C up to 60 ° C. The pressure of the water and / or Diesel-liquid stream is preferably in the range of 0 to 30 bar, particularly preferred from 1 to 15 bar.

The Fragmentation of the water-fluid lamellae to water droplets can supported by different methods.

According to one method, mechanical vibrations, in particular ultrasound, are used for this purpose. The general idea to use ultrasonic waves in an emulsifying device for emulsifying hydrocarbons with water for combustion purposes is from the DE 195 44 554 A1 known, however, does not contain any information about the structural design of the device or to carry out the method.

So may be the entire device in which the water liquid flow with the diesel oil fluid stream is brought together, be subjected to ultrasound.

To a variant of the method, at least portions of the diesel oil liquid stream, the water-fluid lamellae and / or the diesel oil-fluid lamellae and / or the water-in-diesel oil emulsion mechanically vibrated. Particularly preferred the part of a micromixer vibrated, in the formation of the fluid fins takes place and / or in which the water-fluid lamellae with the diesel oil fluid stream or the diesel fluid fins together become.

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

The Frequency of mechanical vibration is at given flow velocity the water-liquid stream and / or diesel oil fluid stream chosen with regard to the particle size to be achieved. This is possible to the effect that the mechanical vibration of the process of fragmentation targeted is initiated. This is the one for a given vibration frequency a close distribution of water droplet sizes, on the other hand can with increase or lowering the oscillation frequency the maximum of the droplet size distribution towards smaller or larger values be moved. This is of particular advantage in the rapid Adjustment of the emulsion to the changing requirements of internal combustion engines.

Prefers are mechanical vibrations in the frequency range from 1 kHz to 100 kHz, more preferably in the range of 10 kHz to 50 kHz.

To a second method is the fragmentation of the water-fluid lamellae supported by the application of an electric field. For this For example, at the area receiving the emulsion stream as an electrode opposite the area forming the fluid fins as a counter electrode a Voltage to be applied. Here are known techniques for electrostatic atomization of liquids (H. Wiggers and P. Walzel, Chemie Ingenieur Technik 1997, (69) 8, 1066-1073.

To In a third method, fragmentation is initiated by introducing a Gas supported. The gas can do this the water fluid stream, the diesel oil fluid stream, the corresponding Fluid lamellae and / or the water-in-diesel oil emulsion are fed. In the simplest case, the gas is possibly purified air. The resulting dispersion of water, diesel oil and gas can be used as fuel be used. However, it is also possible before the gas again at least partially separate. For supplying a gas, so to Production of gas-liquid dispersions can known miniaturized static mixers and known methods Hessel, et al., Gas / Liquid Dispersion Processes in Micromixers: The Hexagonal Flow, in Process Miniaturization: 2nd International Conference on Microreaction Technology, 1998, New Orleans).

One However, gas can be within the water or / and diesel oil fluid stream be generated by that in the Range of the mixer, the temperature is increased so that a volatile component to boil the liquid streams begins and thus gas bubbles are generated in the liquid. It is also conceivable this a liquid flow a volatile one Liquid, For example, a short-chain hydrocarbon to add. The admixed liquid or their gas can be used as part of the fuel for combustion contribute. However, it can also be an inert substance which is separated, for example, after the production of the emulsion.

to Stabilization of the emulsion to be produced may be advantageous the water or diesel oil stream Add at least one emulsion stabilizing substance. This is preferably volume ratio Emulsifier to emulsion up to 1:10, particularly preferably 1 to 5000 to 1: 20. Suitable emulsifiers are, for example, polyethylene oxides and their derivatives, for example, monoethers, polyethylene-propylene copolymers, naphthenic acid and their salts, fatty acids and their salts, fatty alcohols, alkyl sulfates, alkyl sulfonates, alkyl sulfites or their combinations.

at Temperatures below 0 ° C there is a risk that a Supply of water is prevented by crystal formation. in this connection it may be advantageous to at least one of the water-liquid flow the crystallization temperature of the water-reducing substance add. Suitable substances are, for example, mono- or polyvalent ones Alcohols, such as methanol, ethanol or ethylene glycol.

Of Further, it may be advantageous to the water and / or the diesel oil liquid stream at least one fuel property improving substance, such as additives against deposits, add.

To a use is the inventive method for the preparation an emulsion as fuel from diesel oil and one or not with diesel oil miscible liquid or liquid mixture used. For this purpose, instead of a water-liquid flow, a liquid flow the or not with diesel miscible liquid or liquid mixture, for example, one or more monohydric or polyhydric alcohols, such as ethanol or butanol.

To Another use is the process according to the invention for the preparation an emulsion used as a fuel, wherein instead of diesel oil on or several other liquid ones Fuels, such as hydrocarbons, such as gasoline, kerosene, Petroleum ether, LPG, aliphatic or aromatic nitro compounds.

Especially Advantageously, the method is directly in the field of fuel supply an internal combustion engine, for example a motor vehicle diesel engine, used. The water to diesel volume ratio can in this case, for example using an electronic Control, with regard to the current load and / or exhaust emissions the internal combustion engine are adjusted.

variants the method according to the invention will be explained in more detail with reference to schematic drawings. It demonstrate:

1 the known principle of splitting two fluid streams in fluid fins,

2 the principle of splitting a fluid flow in fluid fins and merging with a fluid flow,

3 the housing bottom, the mixing element and the housing cover of a known micromixer separated from each other in a perspective view,

4a after the micromixer 3 cut through the plane of the inlets and outlets,

4b a section representing the element with a gap 4a .

5 the transition from parallel fluid lamellae over fragmenting fluid lamellae to fluid droplets after the micromixer 3 .

6a a micromixer with mixing element movable longitudinally of the gap and coupled to an ultrasound generator, cut from the side,

6b after the micromixer 6a with removed housing cover in plan view,

6c the transition from parallel fluid lamellae over fragmenting fluid lamellae to fluid droplets after the micromixer 6a .

7a a micromixer with a mixing element movable transversely to the gap and coupled to an ultrasound generator, cut from the side,

7b after the micromixer 7a with removed housing cover in plan view,

7c the transition from parallel fluid lamellae over fragmenting fluid lamellae to fluid droplets after the micromixer 7a .

8th a micromixer with electrodes cut to support the fragmentation from the side,

9 Diagram of using the micromixer 3 obtained water droplet size distribution in diesel oil.

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

at the well-known system silicone oil-water was found that the Silicone oil fluid lamellae when merging fragment with the water-fluid lamellae to silicone oil droplets and a Emulsion of silicone oil droplets in a continuous water phase is obtained. These emulsions were at volume ratios from water to diesel from greater than 1: 1 finely dispersed, but with very small volume ratios Distribution of the sizes of the Silicone oil droplets.

opposite Surprisingly, new experiences with water-diesel oil systems have resulted from these known experiences finely dispersed emulsions of water droplets in a continuous Diesel oil phase, in particular at the for Desired fuels volume ratios from water to diesel less than 1: 1.

According to another variant of the method, only the water-liquid stream is split into fluid lamellae and these are introduced into a diesel oil fluid stream, fragmentation of the individual water-fluid lamellae into water droplets taking place. Three corresponding elements 41 . 42 . 51 of a micromixer are in 2 schematically separated and shown in perspective view. In the mixing element 42 there is a feeder 46 for the water-liquid flow, the element 42 is supplied from below by a bore, not shown here. The feeder 46 is in the right area in channels 49a . 49b , ... to split fluid lamellae. On this element 42 is an element 51 with a gap 52 arranged such that the gap 52 over a range of channels 49a . 49b , ... extends. On the element 51 in turn is an element 41 with a feeder 47 for the diesel oil fluid stream, a mixing area 48 and a discharge 43 arranged such that the mixing area 48 above the gap 52 located. For the sake of clarity, the elements 41 . 42 . 51 not on each other, but separated from each other. The feeder 47 and the mixing area 48 are as by the element 41 formed recesses. Only by the arrangement of the element 41 on the element 51 and by a not shown here, through openings for the supply and discharge having cover plate on the element 41 is to be located, are from the feeder area 47 and the mixing area 48 formed chamber-like channels. To achieve one over all channels 49a . 49b , ... same flow are microchannels sufficient pressure loss and a gap 52 provided. To a union of those in the channels 49a . 49b ... to avoid generated water-fluid fins is the element 51 with the gap 52 in the smallest possible thickness, for example, as a slotted foil formed. It is also conceivable, instead of one across all channels 49a . 49b , ... running gap 52 Provide individual column so that they each exactly over a channel 49a . 49b , ... come to rest and cover the adjacent land areas. The element 51 can also be integral part of the element 41 be.

A well-known micromixer 1 who after that too 1 explained principle works is in 3 shown, with the sake of clarity, three parts, the housing bottom 10a , the mixing element 12 and the housing cover 10b , are shown separated from each other in perspective.

The mixing element 12 has two feeders 16 and 17 and an interdigital structure arranged between the two 13 for the formation of fluid fins on. The mixing element 12 is in a corresponding recess 11 in the case back 10a used. The housing cover 10b has two inlets 14 . 15 on, in the bores for supply and discharge 16 . 17 override the corresponding inflow and outflow 16 . 17 of the mixing element 12 are opposite. In the bottom of the housing cover 10b is an element 21 with a gap 22 arranged such that the gap 22 over the interdigital structure 13 of the mixing element 12 to come to rest. In the housing cover 10b and above the gap 22 and connected to this is a dashed line indicated mixing area 18 arranged in which the fragmentation of the water-fluid lamellae to water droplets takes place in a diesel oil phase. The mixing area 18 goes into a likewise dashed lines indicated discharge 23 over, with the outlet 24 connected is. For sealing to the housing bottom 10a is in the bottom of the housing cover 10b an annular groove 27 incorporated for receiving an O-ring seal. For positioning of housing cover 10b and ground 10a to each other, the housing bottom 10a on his top two dowels 28a on that into corresponding holes 28b in the bottom of the housing cover 10b fit. By means of four screws not shown here, the housing cover 10b against the case back 10a be tense, what in the ground 10a four threaded holes 29 and in the housing cover 10b corresponding four through holes 30 are provided.

In 4a is the micromixer 1 to 3 cut through the inlets 14 . 15 and the outlet 24 capturing level. For a better overview, the presentation of details as well as a dotted line of the cut surfaces was omitted. In contrast to 3 are the housing cover 10b and the case back 10a with inserted mixing element 12 shown connected to each other. In 4b is a gap 22 and the subsequent mixing area 18 comprehensive section shown.

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

The process of fragmentation can be specifically supported by the application of mechanical vibrations, such as ultrasound. For this purpose, suitable micromixers and the associated processes of fragmentation are in the 6a -C and 7a -C shown.

In the 6a is a micromixer 60 with a mechanical vibration transmitter in the form of an ultrasonic transducer 65 shown cut from the side. The sectional plane is perpendicular to that in the 4a shown section plane and passes through the outlet 64 and parallel through the gap 63 , The mixing element 62 is in a recess 61 of the case bottom 60a movably arranged, wherein the possible direction of movement is indicated by the double arrow. The mixing element 62 is about a pen 66 with the here only schematically indicated ultrasonic generator 65 connected, wherein the pin through a through hole 67 through the case back 60a is guided. Except for the mobility of the mixing element 62 Connected features, this micromixer 60 the same structure as the micromixer previously shown 1 ,

The micromixer 60 is in 6b with the housing cover removed 60b shown in plan view from above. The interdigital structure can be seen 68 in the mixing element 62 to form the fluid fins. The mixing element 62 is so over the pen 66 with the ultrasound generator 65 connected and so in the recess 61 arranged that the mixing element 62 perpendicular to the interdigital structure 68 predetermined flow direction of the fluid fins and thus parallel to the orientation of the gap 63 is movable.

Like the formation of water droplets 72a . 72b , ... in a continuous diesel oil phase 73 in such a micromixer 60 is done in the two drawings of 6c shown in simplified form. Due to the periodic movement of the mixing element 62 the fluid lamellae of the water run 70a . 70b , ... and diesel 71a . 71b , ... not straightforward, but wavy. By this wave-shaped course, ie by the regular displacement of the fluid lamellae against each other, the process of fragmentation is already deliberately predetermined. From the laterally shifted slats eventually water droplets form 72a . 72b , ... in a continuous diesel oil phase 73 ,

Another micromixer 80 with movable mixing element 62 is in 7a shown cut from the side. The sectional plane is perpendicular to the in 6a shown sectional plane and both through the two inlets 81 and 82 as well as perpendicular to the gap 63 , For easier comparison were in the 7a -C for elements having the same function the same reference numerals as in 6a -C used. As well as from the 7b in which the micromixer 80 is shown with removed housing cover in plan view, it can be seen, is the mixing element 62 in a recess 61 in the case back 60a parallel to that through the interdigital structure 68 predetermined flow direction of the fluid fins arranged movable and correspondingly via a pin 66 with an ultrasound generator 65 connected. The pencil 66 is in a through hole in the housing bottom 60a guided. The mixing element 62 can thus with a periodic movement parallel to the flow direction and thus perpendicular to the orientation of the gap 63 be charged.

The process of fragmentation towards water droplets 72a . 72b , ... is in the two drawings of the 7c shown schematically simplified. The movement of the mixing element 62 takes place parallel to the flow direction of the fluid fins, ie the interdigital structure 68 will be below the gap 63 periodically reciprocated in the direction of the supply of water and diesel oil. Due to the channels in the interdigital structure 68 prevailing pressure difference is at the deflection of the mixing element 62 in the direction of water supply a larger volume flow of water fluid slats 70a . 70b , ... and, when deflected in the direction of the diesel oil supply, a larger volume flow of diesel oil fluid fins 71a . 71b , ... through gap 63 directed. The resulting shape of the fluid fins is shown in the lower drawing in FIG 7c shown. The specifically predetermined by a constriction of areas of the fluid fins fragmentation leads to the formation of water droplets 72a . 72b , ... in a diesel oil phase 73 ,

Another micromixer according to the invention 90 , in which the fragmentation of the water-fluid lamellae is supported by applying an electric field, shows 8th on average from the side. This micromixer 90 has the same structure as the micromixer 1 after the 3 . 4a and 4b on. The mixing element 93 and the outlet 94 , highlighted here by cross-hatching, are over electrical supply lines 95a . 95b with a voltage source 96 connected. The mixing element 93 is to the housing cover 92 and to the case back 91 as well as the outlet 94 to the housing cover 92 electrically isolated. By applying a sufficiently high voltage difference between the outlet 94 and the mixing element 93 Depending on the geometry of the micromixer as well as on the fluids used, fragmentation can be specifically supported. This can be achieved in particular small droplet sizes.

Ausführungsbeisgiel

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

The Emulsions were carried out at a temperature of 22 ° C and without the use of a Emulsifier made.

At the 1:20 mix ratio, a mean water droplet size of about 5 microns was achieved with a standard deviation of 2.5 microns, ie 68.3% of the droplets had a size in the range of 5 microns ± 2.5 microns. The 9 shows the obtained with this example, determined by light microscopy size distribution of the water droplets in the diesel oil phase. The maximum is at a droplet diameter of 5 microns. About 90% of the water droplets have a diameter in the range of 1 μm to 8 μm.

1

micromixer

2

Water liquid stream

3a, 3b, ...

Water fluid lamella

4

Diesel-liquid flow

5a, 5b, ...

Diesel oil fluid lamella

6a, 6b, ...

Water Droplets

7

continuous Phase diesel oil

10a

caseback

10b

housing cover

11

recess

12

mixing element

13

Interdigital structure

14

Inlet for water-liquid flow

15

Inlet for diesel fluid flow

16

Feed for water-liquid flow

17

Feed for diesel oil-liquid stream

18

mixing area

19a, 19b, ...

channel for water-fluid lamella

20a, 20b, ...

channel for diesel oil-fluid lamella

21

element with gap

22

gap

23

removal

24

outlet

27

O-ring groove

28a

dowel

28b

drilling

29

drilling with thread

30

drilling

41

element with mixing area

42

mixing element

43

removal

46

Feed for water-liquid flow

47

Feed for diesel oil-liquid stream

48

mixing area

49a, 49b, ...

Channels for water-fluid louvers

51

element with gap

52

gap

60

micromixer

60a

caseback

60b

housing cover

61

recess

62

mixing element

63

gap

64

outlet

65

ultrasonic generator

66

pen

67

Through opening

68

Interdigital structure

70a, 70b, ...

Water fluid lamella

71a, 71b, ...

Diesel oil fluid lamella

72a, 72b, ...

water droplets

73

continuous Diesel oil phase

80

micromixer

81

Inlet for water-liquid flow

82

Inlet for diesel fluid flow

90

micromixer

91

caseback

92

housing cover

93

mixing element

94

outlet

95a, 95b, ...

electrical leads

96

voltage source

Claims (19)

Process for the preparation of a water-in-diesel oil emulsion as a fuel, comprising the following steps: a) splitting one Water liquid stream in spatial separate water-fluid lamellae of width <100 μm, b) passing the water-fluid lamellae in at least one diesel oil fluid stream, wherein a fragmentation of the water-fluid lamellae takes place in water droplets. Method according to claim 1, characterized in that that before introducing the water-fluid fins the diesel oil fluid stream in fluid lamellae of width <1 mm is split, wherein in each case a water-fluid lamella with in each case at least one diesel oil fluid blade together becomes. Method according to claim 2, characterized in that that several Water-fluid fins and a plurality of diesel oil fluid fins in common be directed into a room, each adjacent to a water-fluid fin with at least one diesel oil fluid blade exit into this room. Method according to one of the preceding claims, characterized characterized in that Width of the water-fluid lamella <50 microns, preferably <10 microns, is. Method according to one of the preceding claims, characterized characterized in that Width of the diesel oil fluid blade <500 microns, preferably <100 microns, is. Method according to one of the preceding claims, characterized characterized in that height of Water or / and diesel oil fluid fins greater than or equal the width of the corresponding fluid fins, preferably> 250 microns, is. Method according to one of the preceding claims, characterized characterized in that Volume ratio of Water liquid stream to the diesel oil fluid stream in the range of 1: 1000 to 1: 1, preferably 1: 500 to 1: 3, is. Method according to one of the preceding claims, characterized characterized in that Water-fluid lamella has a volume flow in the range of 150 to 0.1 ml / h, preferably from 75 to 15 ml / h. Method according to one of the preceding claims, characterized characterized in that Fragmentation of water-fluid lamellae in water droplets Application of mechanical vibrations is supported. Method according to claim 9, characterized in that that the Fragmentation is supported by mechanical vibrations in such a way that at least Areas of diesel oil fluid flow and / or the water-fluid lamellae and / or the diesel oil-fluid lamellae and / or the water-in-diesel emulsion mechanically with vibration be charged. Method according to claim 9 or 10, characterized that the mechanical vibration is such that a periodic deflection parallel or perpendicular to the flow direction the water-fluid lamellae and / or the diesel oil fluid fins is effected. Method according to one of claims 9 to 11, characterized that the Frequency of mechanical vibrations at a given flow velocity the water-liquid stream and / or the diesel oil fluid stream is chosen with regard to the size of the water droplets to be achieved. Method according to 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. Method according to one of the preceding claims, characterized characterized in that Fragmentation of the water-fluid lamellae by applying an electrical Fields supported becomes. Method according to one of the preceding claims, characterized characterized in that Fragmentation of the water-fluid lamellae by a gas in the water-liquid stream, in the diesel oil stream, in the corresponding fluid lamellae and / or in the water-in-diesel emulsion thereby supported will that for this the gas is introduced and / or a low-boiling, upon evaporation the gas-forming liquid above their boiling point is used. Method according to one of the preceding claims, characterized characterized in that Water or / and diesel oil liquid stream at least one emulsion stabilizing, improving the fuel properties or / and the crystallization temperature of the water is lower Substance is added. Use of the method according to one of claims 1 to 16 for preparing an emulsion as a fuel, wherein instead from water another liquid or another liquid mixture, the or not with diesel oil is miscible, is used. Use of the method according to one of claims 1 to 17 for producing an emulsion as a fuel, wherein instead of diesel oil one or more other liquid Fuels are used. Use of the method according to one of claims 1 to 18 in the region of the fuel supply device of an internal combustion engine.