I.e A 30 537-FC FIL~ ~ 2 1 8 9 7 8 3
A ~ devi~P f^~ . ' rP~ With "- r~ f
re ~ ~
In order to carry out a chemical reaction in continuous fashion, it is necessary to
supply the reaction partners ~ y to a chemical reactor and to bring them
into intimate contact, i.e. to mix them thoroughly, with the aid of a mixing elemerlt
10 (mixer). A simple reactor is, for example, a receptacle with an agitator as a mixing
element. A plurality of reactions, so-called main and secondar,v reactions, usually
take place in the reactor when the reactants come into contact. In this respect, it is
the aim of the process engineer to conduct the reactions amd therefore also the
mixing in such a manner that maximum yield of the desired products is selectively
15 achieved.
The quality of the mixing and the infiuence of the mixing element upon the yield of
the desired products depends to a large degree upon the ratio of the chemical
reaction velocity determined by the reaction kinetics and the mixing velocity. If the
20 chemical reactions are slow, then the chemical reaction is usually considerably
slower than the mixing. The gross reaction velocity and the yield of desired
products is then determined by the slowest step, namely the kinetics of the chemical
reactions which take place, and in addition by the overall mixing behaviour (dwell
time distribution, macro mixing) of the chemical reactor which is used. If the
25 chemical reaction velocities arld the mixing velocity are in the same order of
magnitude, this results in complex intPr~tir~ni between the kinetics of the reactions
amd the local mixing behaviours determined by the turbulence in the employed
reactor and at the mixing element (micro mixing). In the event of the chemical
reaction velocities being substantially faster than the mixing velocity, then the gross
30 velocities of the reactions and the yields are essentially determined by the mixing,
i.e. by the local, time-dependent velocity feld and concentration field of the
reactants, i.e. the turbulence structure in the reactor or at the mixing element [1].
. , . ,, . ... , .. , . ... _ .... . ... . .. . . .
LeA30537-FC 2 ~ 89783
The influence of the mixing upon the course of a chemical reaction is ~ uly
great in the case of reactions with concurrent secondary reactions. This state of
affairs can be explained in further detail by way of example of the following reaction
5 pattern (cf Fig. 1):
A + B ~ R .
B + R ~ S
10 In a first reaction step, the two reactants A and B react to produce the desired
product R. A second reaction step follows, in which the desired product R reactsfurther with further starting component B to produce the undesired secondary product
S. Important in the reaction process is tl1at the desired i- Ilr~ product R doesnot come into contact with the as yet urlreacted B and that the reactor is operated as
15 far as possible without repeat mixing.
Schematically simplified in the chemical reactor this means: At the point in time tl,
the starting substances are supplied adjacent one another in fluid balls. S~lb~uutillLly
(t2 > tl), the desired product R forms at the site at which the fluid balls mix
20 together. If the mixing is slower than the reaction velocity of the secondaryreactions, then the undesired seconda~y product S forms as the desired; ., ~l . " l~ r
product R comes into contact with as yet unreacted educt B. This means that it is
necessary to mix the starting ~ c A ~nd B with one another as quickly as
possible in order to prevent the production of the undesired secondary product S.
25 This problem intensifies as tlle reaction velocity increases relative to the mixing
velocity.
According to the state of the art, a series of mixing elements are used for carrying
out rapid reactions in continuous fashion. In this respect, it is possible to distinguish
30 between dynamic mixers, such as agitators, turbines or rotor-stator
systems, static mixers, such as Kenics mixers, Schaschlik mixers or SMV mixers and
jet mixers, such as nozzle mixers or T-mixers [2-4].
.
LeA30537-FC 3 2t 8q783
Nozzle mixers are preferred for the rapid mixing of starting substances in rapidreactions with ull:l~silahlc secondary or auxiliary reâctions.
In the case of jet or nozzle mixers, one of the two starting L~UIIIIJO~ iS sprayed
S at a high flow velocity into the other component (cf Fig. 2). In this case, the kinetic
energy of the sprayed jet (B) is essentially dissipated downstream of the nozzle, i.e.
is converted into heat by the turbulent ~ ;"t~ . of the jet into vortices and bythe further turbulent ~ ;llt~l~lLiull of the vortices into il..,~ ,ly smaller vortices.
The starting ..,,,,1,-,,.. .,~, which are supplied adjacent to one another in the fluid
10 balls (macro mixing, cf schematic illustration in Fig. 1), are contained in the vortices.
Whilst a slight degree of mixing occurs as a result of diffusion at the edges of these
initially large structures as the turbulent vortex ~ r~ ,, begins, complete
mixing is only achieved once the vortex (licintP~rati~-n has advanced to such a degree
that, with the attainment of vortex sizes in the order of magnitude ûf the
15 conrPntrAtirln micrûmass (Batchelor length) [5, 6], the diffusion is rapid enough for
the starting .~"1ll,.", ,~ to mix fully in the vortices. The mixing time required for
complete mixing depends, in addition to the material data and geometry of the
apparatus, essentially upon the specific energy dissipation rate.
20 The mixing processes in the frequently used mixers according to the state of the art
are essentially the same (in dynamic mixers and static mixers the vortices are
additionally mPrh~irRlly distributed, although the specific energy dissipation rates
are cllhctRntiRlly lower in this case). This means that the time taken for the vortex
11icintPgrRtir,n always lapses before complete mixing by diffusion has occurred. For
25 very rapid reactions, this either means that very high energy dissipation rates need
to be employed in order to prevent LLu~U~le secondary or auxiliary reactions, or,
in the case of even greater reaction velocities, the .,ullc~ulldillg reactions are not
optimally carried out, i.e. only with the forrnation of by-products or secondaryproducts.
.
Furthermore, the mixing of two ~ in a ~,i.,lU~LIu~ llc reactor is described
in the state of the art [7]. In a micro reactor for carrying out chemical reactions with
. .. , . . _ .. . . . .
.. ... . .. .. .. . ...
LeA30537-FC 4 2 1 89783
a high thermal effect, the educt currents are ~ ly mixed together within a
;clu~lu~,lul~i. The mixing is effected Yia ll.~ ly extending grooves, which
connect the two material currents together. In this respect, the grooves provided
within the Illh,lui~llu~,lul~ æt as mixing chambers. This mixer offers the advantage
S that the individual material currents are already divided into fine volume elements
within the I~ lu:~llu~lul~, without the material currents thereby coming into contact
with one another. ~s a result, part of the mixing time, which is required for the
turbulent ll~ of the vortices in conventional mixers, is saved and the
mixing is effected more rapidly. However, because the grooves have different
10 lengths, this type of mixing has the d;~advall~ that different pressure losses occur
in the individual channels. This means that the UUUIP(JII~ ; enter the mixing
chamber at different flow velocities at different sites. This results in locallyhct~,.u~ cuu~ mixing within the structure, which in the case of rapid reactions can
lead to ulld~,~ilalJlc secondary and auxiliary reactions. A mixing ~ ,g~ in a
15 column is known from [I l] with mixing, catalyst or channel elements, which can be
arranged in layers. Adjacent elements of a layer and successive elements of adjacent
layers are arranged inclined relative to one another or alternately relative to Ihe main
direction of flow. The elements can be constructed in plate or IIUII~Y~,UI111J fashion
and comprise channels extending parallel to one another. This reduces the flow
20 resistarlce; in the region of the transition from the channel elements to the column
chamber the mixing action is stimulated by turbulence and the joining of the
different partial flows. The mixing elements or the channels thereof can be
constructed entirely or partially as catalysts in order to improve catalytic reactions.
25 Proceeding from this state of the art, the invention is based on the following object.
It is the object of the invention to effect the mixing as quickly as possible in order
to prevent tlle formation of by-products or secondary products. In this respect, it is
necessary to ensure that the educts are h..",~ ." u~ly mixed with one another, so
that no local or temporal excess ..""~ ;.)...s of the educts can be formed within
30 a short period of time. In the case of fluids which react with one another
chemically, the object is to attain a complete reaction of tlle fluids. Where
LeA30537-FC 5 2189783
necessary, it should also be possible to extract o} supply tbe reaction heat effectively
and as quickly as possible.
This object is attained according to the invention in that at least two educts A, B are
5 divided by their respective groups of ~ ,lvullauul~ls in a ~ va~lu~,lul~ mixer into
spatially separated fluid filaments, which then enter a mixing/reaction chamber as
free jets at the same flow velocity for each educt, each free jet of am educt A being
led into the ~ a~,Lion chamber i~ cdi_.~,ly adjacent to a free jet of a different
educt B and the adjacent free jets mixing with one another by diffusion andlor
10 turbulence. Laminar flow conditions are preferably maintained in the llli~,lu~ alul~
for the educts A, B. However, it is also possible to operate with turbulen~ flows in
the Illi~,lul,llalulcls.
An emho~l: n~nt which has proved to be particular expedient is one in which the
15 fluid filatnents of tbe educts A, B enter the Ill;~ g/l~,a~li()ll chamber in alternately
aulJ~I;lll~)uS~v. or adjacent layers.
By way of a ~,ullc;a~ul~vi~ of the Illil,lv.,llallll~ls, it is possible for &e
fluid filatnents of the educts A, B to enter the Ill;~illg/l~a~,~iull chamber in a
20 chessboard pattern.
The geometry of the lllil.lui~lu~Luu._ mixer is ddvallLa~,cuualy designed in such a
manner that the diameter or thickness of the free jets at the entrance to the
a~,Lion chamber can be adjusted to a value between 20 ,um and 250 ~m,
25 preferably between S0 ,um and IS0 ,um. In this respect, the ratio of the centre-to-
centre distance of adjacent free jets and the diameter of the free jets lies in the
region of 1.1 to 2, preferably 1.3 to l.S.
A further dcvclv,ull~cllL of the method according to the invention consists in that a
30 free jet of a tempered, inert fluid is additionally fed into the ..i;~ .,a~,~ion chamber
in the vicinity of a free jet of an educt, for exarnple for heating or cooling purposes.
LeA30537-FC 6 21 89783
The method according to the inYention is therefore based upon the fact that the educt
flows A, B are firstly uu~ ly divided by means ofthe Illi.,l~Llu~,luuc; mixer into
fine volume elements or fluid filaments having a lattice distance d, which filaments
then mix together by diffusion and/or turbulence after entering the mixing/reaction
5 chamber.
It is the task of the llliulu~lu~Lul~ mixer to divide the educt flows Uull~c~ y and
to produce fine fluid filaments having a ~1, . Irl ;~ density d, without allowing the
starting ..., . ,1,, .l-.., l i to contact one another. By way of like geometric .1;1, ,... ,~;~ " ,; "~
10 (like cross section and like length) for the Illi~ lllcls associated with each educt,
it is ensured that the fluid filaments emerge from all channels associated with each
educt at the same flow velocity. In the case of two educts A, B, the flow velocities
in the Illi.,l.l.,lldllll.,ls of each educt are therefore the same. However, the flow
velocities of the two educts (in relationship to one another) can also be entirely
IS different.
In this manner, local educt ~i~trihlllilm is achieved which is as hom~nPoll~ as
possible. A density d is preferably adjusted which lies in the order of magnitude of
the con~Pntr~fiflr micromass, so that the Illi~,lUlllihil~g of the ~,ulll~oll~llb can be
20 effected rapidly by diffusion downstream of the l~ o-LIu~,luu~ mixer, without the
need for any further vortex ~licinfP~r~tion
As a result of the method according to the invention, it is possible the save a
cull~id~lal,L, amount of time for the turbulence ~ r~ ll during mi~ing and
25 therefore to considerably accelerate the mixing process. As a result of the division
of the educt flows into extremely fine volume elements within the microstructure,
without the educt flows coming into contact with one another, and as a result of the
o~ vuj distribution of the educts as they leave the mic..~LIuu~uu~, it is
possible to closely reproduce the mixing behaviour of an ideal pipe reactor. In the
30 case of rapid reactions, ulll~,.,;labl~ by-products or secondary products occur to a
considerably reduced degree as compared with state of the art mixers A main
application is therefore rapid reactions having ,ll~ld~ Lic reaction times <lOs and
.
_, .. . .. .. . .. . .. . .. . . .
Le~30537-FC 7 2 1 89783
in particular <Is. "Reaction time" is usually understood to be the half-life, i.e. the
time following start of the reaction after the educt r~nr~ntrAtil)n has fallen to the half
va~ue.
In order to carry out the method according to the invention, a static ~
having at least one mixing chamber and an upstream guide component for the supply
of mixing or reaction fluids (educts) has proved expedient. In this respect, the guide .
component is formed by a plurality of plate-like elements which are ~ "l--~s- ~lin layers and which are penetrated by channels extending at an angle to the
0 lnn~itl~flinAl axis of the ~ lul~ , the channels of adjacent elements illlrwithout contact and opening into the mixing chamber. This device is . l,,. ~ f
according to the invention by the following features:
a) The plate-like elements are made of thin films, in which a group of closelyadjacent grooves extending at alternate angles to the l-n~itll~1inAI axis ofthe
u,i~,.ù...;~-~, is formed, so that when the films are ~ ,.l,n~c~l in layers a
row of closed channels is formed for conducting the fluids (educts A, B)
which are to be mixed.
20 b) The grooves have widths and depths of <250 llm with wall thicknesses of the
i~f~ webs and groove bases of <70 llm.
c) The rows formed by the films of channel openings adjoining the mixing
chamber are ~u~ OSf ~ in alignment, the rows of channels of adjacent
films diverging towards the fluid entry side of the ll~ lh~l, so that the
fluids (educts A, B) which are to be mixed can be supplied separately.
Alternatively, an illt~ ' film can be provided in each case between two films
having the inclined grooves diverging towards the fluid entty side, the i.,lr",.f~
film comprising grooves extending pe"~ lar to the Illi-,ll~lll;X~Ci Inn~itllrlinAl axis
and being used for conducting a cooling or heating agent
LeA30537~FC 8 2 1 89783
According to a further alternative, a micro heat exchanger is connected to the mixing
chamber. However, the mixing chamber per se can be constructed as a micro heat
exchanger, which is directly connected to the guide component.
5 Using the device according to the invention, the fluids which are to be mixed are
divided in rows and in "staggered" fashion into a plurality of extremely fine,
extremely closely adjacent flow filaments (fluid filaments), which, wllen brought
together at the entrance to the mixing chamber, fill a common, Coll~DI.u~ ly
narrowly defined volume and can therefore irltermix with maximum speed and over
10 the shortest possible distance. The density of the channel openings and therefore of
the flow filaments at the entrance to the mixing chamber is several thousand
openings or flow filaments per cm2.
The device according to the invention allows for the mixing of two or more fluids.
15 When chemically reacting fluids (educts) are mixed together, the reaction heat which
is thereby produced (exothermic reactions) or required (r~lill.ll....",;~ reactions) can
be drawn off or suppiied through the connected micro heat exchanger.
Using the method and device according to the invention, the following further
advantages can be achieved:
luv~ of the yield, selectivity and product quality in known reactions
- Production of products with new property profiles (e.g. higher purity)
2~
- M;~ m of reactors and mixers, optional~y in combination with heat
exchangers
- Improvement of the safety standard irl exothermic reactions by reduction of
hold-ups and optionally by reduction of the dimensions of the I~ ,lu~ dn
to below the quenching distanco (improved ignition backfiring safety!).
LeA30s37-~c 9 2 1 89783
The invention will be described in further detail in the following with the aid of
bodilll~ and drawings. In the drawings:
Fig. I is a schematic illustration of the mixing and reaction of two reactantsS in the form of fluid balls A, B (state of the art),
Fig. 2 shows the mixing of two reactants A, B (educts) in a jet/no7~1e mixer
(state of the art),
Fig. 3 show3 the basic structure of a IlliClUllliA~::l for two educts A, B with
~yllu~l~,.fi~,al flow paths,
Fig. 4 shows the mixing of the free jets associated with the educts A, B
entering the mixing or reaction chamber from the llli~,lu.,ll~uulcl mixer,
Fig. 5 shows an ~,lllbodilll~ L in which the spatial ~ of the fluid
filaments associated with the educts A, B upon entry into the
mixinglreaction chamber is characterised by alternately :.U~)C~lilll~JO:~,d
layers,
Fig. 6 shows an alternative ~."I.~,.I;l". ,l to Fig. 5, in which the fluid
filaments of the educts A, B enter the mixing/reaction chamber in a
chessboard pattern,
Fig. 7 is a circuit diagram for an apparatus for testing chemical reactions
ta~ing place according to the method of the invention, arld
Fig. 8 shows the kst results obtained using the apparatus according to Fig.
7 in the ca3e of the azo coupling reactiûn of a-naphthol with 4-
sulfonic acid benzol dia onium salt,
LeA30537-FC lo 2~ 89783
Fig. 9a shows a plurality of films which are to be stacked as CU~ Ul~ for
the l-lh,lu~ auulel mixer,
Figs. 9b and 9c, are two views of a guide component made of films according to
S Fig. 9a,
Fig. 9d is a schematic illustration of the fiow behaviour in a Illiwo~ uu
mixer,
10 Figs. IOa and lOb are schematic illllctr~tionc of a Ill;~,~u~,llauul~,l mixer with a
coolable or heatable guide rr~mrrnrnt
Fig. I la is a section through a I~ ,lu~.lla~ cl mixer, to whose mixing chamber a heat exchanger is connected, and
Fig. I Ib shows a IlFi~,lu~ alulel mixer with a mixing chamber constructed as
a heat exchanger.
Fig. 3 is a schematic illustration of a ll~;I,lU:~ilUl,~UlG mixer (Ill;~lu~,llalul~.l mixer)
20 suitable for carrying out the method according to the invention. The structural
principle of this mixer is based on the fact that different layers of plates with
inclined grooves or furrows are stacked vertically in sandwich fashion. A structure
of this type is described, for example, in DE 3 926 466, in particular in association
with Fig. 1. Express reference is made to this description.
A plate with ~ lu~,llalulcls Ib follows each plate having furrows or Illh,lu~,llalul~,ls
la, i.e. two plates stacked one on top of the other are provided in each case with a
group of mi- IO~,llalulcls la, Ib, the Illh,lU~,IlaUUlCl groups of successive plates forming
an angle a with one another and being arranged ~yllullGII;cdl to the horizontal axis
3û in Fig. 3, i.e. in mirror-inverted fashion relative to one another. The plates have a
thickness of, for example, 100 llm. The clear width of the l~ lu~hdlulcls lies
typically in the order of magnitude of 70 llm.
.. . . . ......... . _ ... . . . _
LeA30537-FC ll 2 1 89783
t he groups of microchannels I a, which extend upwards at an angle from the centre
of the drawing in Fig. 3, open on the lefl into a distribution charnber 3a, to which
a reactant or educt A can be supplied. In analogous fashion, the groups of
l";~lo~ ull.~,ls lb, which extend downwards at an angle, open on the lefl into a5 ~liqtrihllti~n chamber 3b, to which an educt B (reactant) can be supplied. Both
groups of ~ ,lul,llauul~,13 open on the right, without i-~t~ " into a common
mixing/reaction chamber 4. The mirror-inverted <ulaul~,C~ of the Illi~,lul,lla~.~ls
la, Ib is not essential. The I~ ,lUCl~L.~ Ib can, for example, have a different
angle of inclination relative to the horizontal axis than the ~ "u~ uulcl~ la.
However, it is important that the Il;u~uul-~uul~,ls of a group are all alike from the
point of view of flow technology, i.e. that the Ill;~,lu~,Lal~ ,ls la all have the same
flow resistance. The same condition applies for the flow resistance of the
ll~iulù~,llal~l~,ls Ib, although the flow resistance3 of the two l~ ,lu~,llallll..l groups la,
15 Ib can differ (in l~.la~;ullalli~ to one another). Like flow resistance can be attained
by providing a like length and like cross section for all l~ ,luulla ll~el~ la.
The educt which is supplied to a ~lic~rihlltir~n chamber 3a, 3b, e.g. a gaseou3 reactant,
is distributed in each ca3e irto the ~lu~,lu~,llallllcl~ la, Ib. The two reactants are
20 brought together upon entry into the mixing/reaction chamber, as is described in
detail below with reference to Figs. 4 to 6. The cross section of opening of themicrochannel mixer is shown in Fig. 4.
In the uppermost layer or plate, the mi.ilu.,ll~u,llels la a3sociated with the educt A,
25 for example, open into the ~ dllg/.ca~,~ion chamber and in the underlying layer or
plate the Illi~,lu~llallll~,ls Ib of the educt B open into said chalnber. This is again
followed by layer or plate with the Illh,lu~llallll~l~ belonging to the educt A, etc..
Fig. 4 also 5f h~m~til ~11y illustrates how the fluid filaments conducted in themi-,-u~,ha-~ ls enter the ll-;~i,.~/l.,~, ~ion chamber as fine jets 6a, 6b and mix together
30 with increasing distance from the opening. The mixing is effected by diffusion
and/or turbulence, whilst laminar flow conditions u3ually prevail in the
mi.,lucl~al..l~ls. At the same time as the mixing, the reaction of the educts A, B
., ... ,,, .. . ... _ , , ,
Le A 30 537-FC 12 2 ~ 8 9 7 ~3 3
takes place. The reaction product is extracted at the end of the Illi;~ a~ ~iUIIchamber (cf Fig. 3). Fig. 5 again shows the spatial sequence in which the educts A,
B enter the mixing/reaction chamber at the opening cross section. A layer of fluid
filaments of the educt A thus adjoins a layer of the fluid filaments of the educt B.
S The ~ can, of course, also be rotated through 90, so that the layers are
adjacent one another. One variation, in which the fluid filaments of the educts A,
B enter the Illi~ g/l. a~ Lion chamber in a chessboard pattern, is illustrated in Fig. 6.
An " ~ ,f ~ 'l of this type can be practically realised when plates with
,l~ul~ l~ la, Ib are stacked in the direction of the arrow (cf Fig. 6) and the
10 ~, ....g~.. "... ,t is such that the channel openings of one layer are offset relative to the
openings of the following layer.
The Illi~ ,hdlU~'_I mixer according to Fig. 3 can also be modified in such a manner
that three or more educts are divided into separate groups of ll~ ll~ul~ ls in each
15 case, which are then brought together in the Illi~ iOn chamber. An interesting
variant from the point of view of method technology is where the third educt is
formed by a tempered, inert fluid. The fluid filaments are then conducted in theiCI~u llalulcl mixer in such a manner that a free jet of the tempered, inert fluid is
fed into the ~ dllg/lca.,tion chamber in the vicinity of a free jet of an educt for
20 heating or cooling purposes.
A practical design of the Illi~ llalll.. l mixer which has proved palli~ lllallyexpedient is described in the following with reference to Figs. 9a to I Ib.
The films I and 2 according to Fig. 9a have a thickness of 100 llm and a length and
width in the millimetre range. The film type I is penetrated by a group of
preferably para~lel, closely adjacent grooves or mi~lu.llalulcls which extend at an
angle to the mixer longitudinal axis 3 and, proceeding from the rear lefl, form an
acute angle +a with said axis 3 and open in the central region of the front
I.~ ,l.l;";\l side of the film. The film type 2 is penetrâted in the same manner by
grooves or l~ llalùl~l~ Ib, but in this case the angle between the groove
lon~itll-linAI axis and the mixer lnn~itll-iinAI axis is -o, i.e. the grooves Ib extend
., . _ . . . . .... .. . ... . . . . . _, . _ .. .
21 89783
Le A 30 537-FC 13
from the rear right to the central region of the front 11"".;~.,.1;"~1 side of the film.
The size of the angle does not need to be the same in each case. The grooves la,Ib can be formed by profile diamonds and preferably have a width of <100 llm, a
depth of 70 ~Lm and a thickness of the jllt~ ; /t~ webs Sa, Sb of 15 llm. The
S thickness of the groove bases 6a, 6b is 30 llm.
The tools and devices required for the Illallura,~ of micro grooves of widely
ranging cross sections are illustrated and described, for example, in DE 37 09 278
C2. The arrows A and B symbolise the flow directions of the fluids A and B whichiO are to be mixed.
For the Ill~lura~L~ , of a guide component 6, the film types I and 2 are arlanged in
altemate layers, are provided with an upper and a lower cover plate 7a, 7b and are
connected, for example by means of diffusion welding, to fomm a l.."".~g..,~
15 vacuum-proof and pressure-proof lui~,luaLIu-,L ue element. As shown in Fig. 9b, the
rows 8a, 8b fommed by the films I and 2 of openings of the channels la, Ib
adjoining the mixing chamber 4 are arranged above one another in alignment (cf also
Fig. 9d).
20 These rows 8a, 8b fomm a common, e.g. square cross section having a density of
approx. five thousand openings per cm~, which adjoin the common mixing chamber
4. Fig. 9c shows the guide component 6, viewed from the inflow side of the fluids
A and B. As shown here and in the plan view of Fig. 9d, the channels la, Ib
extending at am angle to the lon~ in~l axis 3 diverge from the mixing chamber 4
25 altemately towards the fluid supply side, so that the fluids A and B can be supplied
separately to the fluid component 6 via an inlet chamber or distribution chamber 3a
and 3b respectively. Afler emerging from the guide component 6, the fine flow
filaments (free jets) 6a, 6b of the fluids A and B are intimately mixed and form a
common flow C in the mixing chamber 4 (cf also Fig. 4).
Figs. IOa and IOb show a variation, in which i,,~ . ",~ ^ films 8 are fitted between
two film types I and 2 or between the fi~ms and the cover plates 7a, 7b, the
_ _ .. . .. . . .. ... . ... .... . . _ . .. .
LeA30537~FC 14 21 89783
int~rm~ films comprising grooves 9 extending perpendicular to the longitudinal
axis 3 for corlducting a cooling or heating agent. In this manner, the mixing~ timc
and the reaction velocity of the fluids ~ and B can be influenced.
5 Fig. I la is a section through a fluid component 6 according to Figs. 9a and 9d with
an adjoining mixing chamber ~. Cormected to this mixing ehamber is a heat
exchanger 10, whieh similar to the variant according to Figs. lOa and lOb is
penetrated by ehannels I la extending Ll~ls~ ,ly to the flow direetion C for theextraetion or supply of the reaetion heat from or to the ehannels I Ib.
In Fig. I l b, the heat exchanger 12 is directly cormeeted to the guide eomponent 13.
In this ease, the ~ ." ,l is corlstructed with spacing films 1~ in such a mannerthat two ~up~,.;lllpo~J ehannels 13a, 13b for the fluids ~, B open in each case into
a eommon partial mixing ehamber 12a of the heat exchanger, the said partial mixing
1~ chambers 12a adjoining films 12b, which comprise channels 12c extending
transversely to the flow direction C. These ehannels 12e eonduet a eooling or
heating agent, by means of which heat ean be extraeted from or supplied to the
mixing and reaetion zones 12a.
LeA30537-FC 15 2 1 89783
Irl order to assess the mixing behaviour of widely varving types of apparatus, the azo
coupling reaction of alpha-naphthol with 4-sulfonic acid benzol diazonium salt is
5 used in the literature [2, 8, 9]. These reactions cortespond to the above-described
reaction pattern of a reaction with secondary reactions, it being possible to analyse
the secondary product in a simple manner with the aid of absorption spectra. Thequality of the mixing process is assessed by the selectivity of secondary products S,
Xl3. The more S which is formed, the poorer the mixing.
The method for carrying out rapid chemical reactions using III;UIO~IlU._~Ull_ mixing
was examined in the apparatus shown in Fig. 7. This apparatus comprises the
storage receptacles 15 for the starting ~ A and B, the metering and control
devices 16, filters 17 for protecting the Illi~ lU~Ull~ mixer from blockages, the
5 Illi.~ lU~ mixer 18 and the collection receptacle 19 for the product mixtute.
The ~ u~,~ul~ mixer which was used generated fine jets having a width of lO0
m and a height of 70 llm. The jets were arranged in such a manner that the
~ Olll~)oll~ A and B emerged from the mixer in alternate su~J~,l;lllpo~J layers.
20 Volume flow ratios o = VA/VB of 10 and 20 were adjusted. In this respect, themethod was carried out with l~ ,. ",~ " ~ characteristics ~ greater than 105. The
reaction-kinetic data and the ~ ' ' for the use of model reactions can be
derived from the litetatute [2, 8, 9, I0].
25 The method was carried out with a ~ tl;c ratio of l.05 and a constant
naphthol initial ~on~ntrAtion of 1.37 mol/m3. The L~.,.rullll~ulu~ ~hArArt~ricti~ ~ is
calculated as follows:
V = ~Pn~ph --V=ph. ~ ~P~ul~. V5UIf) / {k2 C~o 11 ~V=Ph. -t VSUIE)}
with
LeA30537-FC 16 2 1 89783
~PUlph shock loss naphthol solution in mixer
~r5~1s sllock loss sulfanilic acid solution in mixer
Vn~ph volume flow naphthol solution
VSUIL volulne flow sulfanilic acid solution
kl reaction velocity constant secondary reaction
c~O initial concentration naphthol
dyn. viscosity
In Fig. 8, the selectivity of ~ secondary product X~ is plotted against the
10 performance~
It was found that for the volume flow ratio of 10 and 20 with the same
performance i.l.,.,~. ~. .;~lic in the metllod according to the invention (curves O and
[1) r~nci~iP~hly less "".1i-~;.,.l.l~ secondary product was formed than with the use of
15 nozzle mixers according to the state of the art (nozzle mixer with smooth jet nozzle,
nozzle mixer with smooth jet nozzle and fltting to prevent repeat mixing) (broken-
line curves). The data ~ ~olldil~ to the broken-line curves is derived from the
literature [2, 8, 9, 1 l. This finding is completely surprising, if we proceed from the
existing hypothesis that the mixing intensity is determined solely by the ~lrOI~l!all.
20 ~,llalal L~ lic and the material data.
LeA~0537-FC 17 2 1 89783
L~
[I] Brodkey, R.S. (ed)
Turbulence in Mixing Operations
Theory and Application to Mixing and Reaction
Academic Press, Inc., New York, San Francisco, London, 1975
[2] Tebel, K.H.; May, H.-O.
Der I Iti~llahl~ llcahLul - Ein effektives R~ ,Id~ ll zur U~ ,ldlu.,kuulg
vonScl~ivil~b~ lu,t~,ldurchschnelle,ul~l~.ull~ Fo4~
Chem.-Ing.-Tech. MS 1708/88, Synopse in Chem.-Ing.-Tech. ~, 1988
[3] Zehner, P.; Bittins, K.
Du~ t~oltll
Fortschr. Verf. Techrlik ~, 1985, 373
[4] Tosun, G.
A Study of Micromixing in Tee Mixers
Ind. Eng. Chem. Res. ~i, 1987, 1184
[5] Batchelor, G.K.
Small-scale Variaeion of Convected Quantities Like Temperature in Turbulent
Fluid
J. Fluid Mech. 5, 1959, 113
[6] Baldyga, J.; Bourne, J.R.
Micromixing in Tnh~-mon~nPol-c Turbulence
Chem. Eng. Sci. ~, 1988, 107
LeA30537-FC 18 2 1 89783
[7] Schmidt, P.; Caesar, C.
Mikroreaktor zur Durchfuhrung chemischer Reaktionen mit starker
W.1""rl;;",.,~ und Offi nl~ ";n DE 39 26 466 A I
5 [8] Brodkey, R.S.
Fun~l~mrnt~ of Turbulent Motion, Mixing and Kinetics
Chem. Eng. Commun. ~, 1981, ~
[9] Bourne, J.R., Hilber, C.; Tovstiga, G.
Kinetics of the Azo Coupling Reactions Between l-Naphthol and Diazotized
Sulfanilic Acid
Chem Eng. Commun. ~Z 1985, 293
[101 Bourne, J.R.; Kozicki, F.; Rys, P.
Mixing and Fast Chemical Reaction 1:
Test Reactions to Determine Segregation
Chem. Eng. Sci. ~, 1981, 1643
[I l] WO 91/16970 Al
