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Device and method for a bioreactor, catalysis reactor or crystallizer without internals
The present invention relates to a device and method for a bioreactor, catalysis reactor or crystallizer without internals, comprising at least one first cilindrical or rectangular fluid channel with a fluid inlet and a fluid outlet, at least a second and preferably also a third fluid 5 side channel both connected to the first cilindrical or rectangular fluid channel, acoustic wave generating means that are connected to at least the second and preferably also the third fluid side channels and that are capable to produce wave interference in at least the first cilindrical or rectangular fluid channel, control means for controlling the wave generating means capable to achieve a structure with the generated waves such that at 10 least two node lines are formed in the first cilindrical or rectangular fluid channel whereby a significant angle of at least 5 degrees exists between at least two node lines and the axial direction of the first cilindrical or rectangular fluid channel. With the device and method according to the present invention, microorganisms and / or catalyst particles and / or crystals are immobilized in the first cilindrical fluid channel without using any internals and / 15 or adsorption media in the first cilindrical fluid channel. As a result, a very effective bioreactor and / or catalysis reactor and / or crystallizer is obtained since mass transfer limitation is suppressed in such a reactor.
Introduction 20 In the (bio)chemical process industry and the water purification industry, most chemical and biochemical reactions are heteregeneous i.e., the reaction takes place at a solid - liquid interface, a liquid - liquid interface, a solid - gas interface or a liquid - gas interface. Some examples of heterogeneous reactions are crystallization reactions, biochemical conversions by microorganisms and catalytic conversions in fluids by the use of a solid catalyst. An 25 important process design parameter in heteregenous reactors is the total surface area of the interface at which the reaction takes place per volume unit of the reactor. For catalysts, the specific surface area [m2/g] is an important parameter defining the efficiency of the catalyst. Both the reaction rate and often also the selectivity of heterogeneous reactions comprising liquid - solid or liquid - liquid reaction interfaces are usually limited by mass 30 transfer limitation for both transport of reactants from the bulk of the liquid phase to the reaction surface and by mass transfer limitation for transport of reaction product from the reaction surface to the bulk of the liquid phase. In those cases, the diffusion coefficient of the different components in the liquid phase(s) determine mass transfer. A small diffusion coefficient of a reactant will result in a low concentration of that reactant at the reaction 35 surface and hence in a low reaction rate. For these reasons, the performance of heterogeneous reactors can be improved considerably by increasing the surface area of the reaction surface and / or by increasing the diffusion rate of reactants from the bulk of the 1039053 , f 2 liquid phase(s) to the reaction surface and reaction product from the reaction surface to the bulk of the liquid phase(s).
The present invention relates to a device and method to improve the efficiency, rate and / or selectivity of heterogeneous reactions in general. More specifically, the present invention 5 relates to a device and method for a bioreactor and / or a catalysis reactor and / or a crystallizer.
Description of the technology according to the present invention
According to a first aspect, the present invention relates to at least one first cilindrical or 10 rectangular fluid channel with a fluid inlet and a fluid outlet. This first cilindrical or rectangular fluid channel is preferably equipped with at least an inlet and an outlet to enable a continuous fluid flow through the channel.
According to a second aspect, the present invention relates to at least a second and preferably also a third fluid side channel, both connected to the first cilindrical or rectangular 15 fluid channel. Preferably, at least one fluid side channel is connected to acoustic wave generating means. More preferably two fluid side channels are connected to acoustic wave generating means. Most preferably more than two fluid side channels are connected to acoustic wave generating means.
According to a third aspect, the present invention relates to control means for controlling the 20 acoustic wave generating means of at least a second cilindrical fluid side channel.
Preferably more than one cilindrical fluid side channels are equipped with controlling means for controlling the acoustic wave generating means. Most preferably, the controlling means for controlling the acoustic wave generating means are controlled by the use of at least a microprocessor and software.
25 According to a fourth aspect, the present invention relates to at least one sensor for sensing properties of the fluid present in the first cilindrical or rectangular fluid channel. Preferably the sensing principle of at least one sensor for sensing the fluid properties in the first cilindrical or rectangular channel is based upon at least one of the following sensing techniques: acoustic measurements, light scattering measurements, light reflection 30 measurements, conductivity measurements, pH measurements, temperature measurements. In case temperature measurements are applied, these measurements preferably comprise temperature measurements using infrared technology and / or PTCs and / or NTCs and / or Pt100 sensing elements preferably placed in the fluid of the first cilindrical or rectangular fluid channel and / or connected to the inner wall and / or outer wall 35 of the first cilindrical or rectangular fluid channel.
The signal(s) produced by the sensor(s) for sensing the fluid properties are preferably fed to a microprocessor, preferably to a microcontroller, preferably by the use of an analog to
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3 digital converter.
According to a fifth aspect, the present invention relates to software for controlling the acoustic wave generating means. Preferably the software contains a feed back loop from the sensor to the acoustic wave generating means.
5 According to a sixth aspect, the present invention relates to software for controlling the acoustic wave generating means in such a manner that wave interference occurs so that node lines and / or node regions are produced in the first cilindrlcal or rectangular fluid channel. In these node lines and / or node regions solids will collect, resulting in a heterogeneous system of solids that are suspended in fluid.
10 Figure 1 gives a schematic overview of the technology according to the present invention. It is noted that figure 1 is one of the many possible embodiments of the technology according to the present invention and the present invention is by no means limited to figure 1.
The arrows 1 and 2 in figure 1 show the flow direction of the fluid. C1 relates to the first cilindrical or rectangular fluid channel. It is noted that the cilindrical or rectangular shape of 15 the first fluid channel is a preferred embodiment. It is stressed that a large number of other geometrical shapes of the first fluid channel are technically feasible and part of the technology according to the present invention. Fluid channels C2 and C3 relate to the second and third fluid side channel respectively. A1 and A2 relate to the first and second acoustic sound generating means respectively. The angle p relates to the angle between 20 the first cilindrical or rectangular fluid side channel and the second fluid side channel. According to the present invention, this angle is at least 5 degrees. It is noted that the angles between the different fluid side channels and the first cilindrical or rectangular fluid channel may be different. It is also noted that the location at which each fluid side channel is connected to the first cilindrical or rectangular fluid channel is a design parameter. Further, it 25 is noted that other shapes of the fluid side channels than cilindrical or rectangular, such as, but not limited to, polygonic channels and / or intersections are possible and part of the present invention.
Now the basics aspects of the technology according to the present invention have been explained, a number of preferred embodiments will be discussed.
30 A first preferred embodiment of the present invention comprises application of the technology according to the present invention as a crystallizer. For this purpose, seed crystals and / or a supersaturated solution are fed into the first cilindrical or rectangular fluid channel that performs as a crystallizer. Preferably, the first cilindrical fluid channel is a flow through reactor with a fluid inlet and outlet as shown in figure 1. The crystallizer can be 35 operated in a recirculation loop in such a way that a CSTR (continuously operated stirred tank reactor) is formed. Alternatively, the crystallizer can be operated as a plug flow reactor or as a fed batch reactor. In the latter case, reactants are preferably fed into the reactor at a 4 desired rate, thereby increasing the reaction volume.
A crystallizer according to the technology of the present invention has following advantages as compared to prior art crystallizers: 1. Since the crystals are captured in node lines and / or in node regions, they are 5 suspended in the reaction mixture without introducing a high collision rate and / or shear rate near the crystal surface. At these conditions, it is possible to produce very pure crystals with a very low concentration of defects near the crystal surface.
2. Because of the acoustic waves in the solution, the apparent diffusion coefficient of the molecules in the solution is increased. This is even the case in the node lines 10 and / or node regions in which or near which the pressure fluctuations are never perfectly reduced to zero. As a result of the increased apparent diffusion coefficient, mass transfer of the reactants to the crystal surface is enhanced, resulting in a higher crystallization rate as compared to the situation that acoustic waves would be absent.
15 3. The volume fraction of crystals in the node lines and / or node regions can be set at a desired level by proper design of the first fluid channel and the fluid side channel(s). Fine tuning can be realized by adjusting the frequency and / or amplitude of the acoustic waves.
4. Once the crystals exceed a predefined size, they cannot retained anymore by the 20 node lines and / or node regions and can be tapped from the crystallizer. In this way a very narrow crystal size distribution can be realized.
It is clear to a person skilled in the art that the technology according to the present invention opens possibilities to improve the product quality of crystallization products in chemical and pharmaceutical industry and to improve the performance of water purification processes 25 comprising crystallization of inorganic salts. Since the technology according to the present invention makes it possible to retain very small crystals in the crystallizer, high crystallization rates can be achieved with only a limited total crystal mass. It is noted that the crystallizer according to the present invention can be applied as a crystal nucleator and / or to destroy crystals or crystal aggregates by the use of ultrasound.
30 A second preferred embodiment of the present invention comprises application of the technology according to the present invention as a reactor for biomass such as bacteria.
For this purpose a suspension of desired micro-organisms is added to the first cilindrical or rectangular fluid channel. In analogy with the crystallizer application, the biomass reactor can be operated as a CSTR, a plug flow reactor or as a (fed) batch reactor.
35 A biomass reactor according to the present invention has following advantages above prior art biomass reactors: 1. The reactor can be made selective for the desired biomass i.e., for the size and 5 shape of the micro-organisms that should be retained in the node lines and / or node regions. This means that other biomass or particles will leave the reactor after only a very limited residence time. Hence, the reactor will mainly contain the desired microorganism. This desired situation can be achieved with even higher precision in case 5 the technology according to the present invention is combined with other specific selective process conditions such as temperature, (ultra)sound frequency, alternating electric field, fluid composition.
2. In analogy with the crystallizer according to the present invention, the apparent diffusion coefficient of dissolved components in the fluid is increased, thereby 10 increasing mass transfer to and from the micro-organisms.
3. Formation of a biofilm is suppressed and micro-organisms are suspended as single cells or small aggregates. Also this enhances the conversion rate that can be achieved per gram of biomass.
A third preferred embodiment of the present invention comprises the application of the 15 technology according to the present invention as a catalysis reactor. In analogy with the crystallizer application, the catalysis reactor can be operated as a CSTR, a plug flow reactor or as a (fed) batch reactor.
A catalysis reactor according to the technology of the present invention has following advantages above prior art catalysis reactors: 20 1. Since the catalyst particles are captured in node lines and / or in node regions, they are suspended in the reaction mixture without introducing a high collision rate and / or shear rate near the catalyst surface. This will increase the performance and life time of the catalyst and opens possibilities to successfully apply catalyst particles with only limited mechanical stability.
25 2. Because of the acoustic waves in the solution, the apparent diffusion coefficient of the molecules in the solution is increased. This is even the case in the node lines and / or node regions in which or near which the pressure fluctuations are never perfectly reduced to zero. As a result of the increased apparent diffusion coefficient, mass transfer of the reactants to the catalyst surface is enhanced, resulting in a 30 higher reaction rate as compared to the situation that acoustic waves would be absent.
3. The volume fraction of catalyst particles in the node lines and / or node regions can be set at a desired level by proper design of the first fluid channel and the fluid side channels. Fine tuning can be realized by adjusting the frequency and / or amplitude 35 of the acoustic waves.
4. In case the reaction product is a solid, reaction conditions can be chosen such that the reaction product is not captured in the node lines and / or node regions because 6 of the characteristic particle size of the product. As a result, the reaction product will leave the catalyst reactor whereas the catalyst remains suspended in the catalyst reactor. Hence, a separation step between catalyst and reaction product can already be achieved in the catalyst reactor without introducing additional separation steps.
5 A third preferred embodiment comprises application of the technology according to the present invention in combination with a so-called coax sensor. In this particular case the sensor is applied as a preconcentration system and sensor at the same time. An example of a coax sensor is an open ended quarter wave length coaxial stub. Such a sensor can be applied as in line flowthrough sensor with fluid inlet and fluid outlet. Depending of the 10 dielectric properties of the fluid pumped through the coaxial stub, the resonant frequency and quality factor of the filter will change. By equipping the coaxial stub with fluid side channels and acoustic wave generating means according to the present invention, a coax sensor with integrated particle concentration system is obtained. In fact, the coaxial stub is in this case applied as first cilindrical or rectangular fluid channel according to the present 15 invention. It is noted that the particle concentrator can be switched off easily by switching off the acoustic sound generating means. In this way, the concentrator is flushed. Preferably, the diameter of the side channels, connected to the first cilindrical or rectangular fluid channel according to the present invention, is sufficiently small to avoid undesired interaction of the side channel with the electromagnetic waves fed to the coaxial stub.
20 The coax sensor can be applied as a sensor to monitor the conversion and performance of a bioreactor, catalysis reactor or crystallizer.
A fourth preferred embodiment of the present invention comprises application of the technology according to the present invention with a first cilindrical or rectangular channel that is equipped with internals i.e., geometrical structures, in order to optimize the 25 effectiveness of the node lines inside of the first cilindrical or rectangular channel.
The frequency of the acoustic waves applied in the technology according to the present invention is in the range of 100 Hz to 1 GHz. Preferably ultrasound is applied. More preferably ultrasound in the frequency range between 20 kHz and 100 MHz is applied. Finally, it is noted that the technology according to the present invention brings along 30 following advantages as compared to prior art reactors: 1. Absence or at least strong reduction of reactor fouling because of the acoustic vibrations in the reactor 2. Increase of the apparent diffusion coefficient of components present in the fluid, resulting in higher reaction rates and / or higher selectivity of the desired reactions.
35 3. Absence of undesired particle shear and / or particle collisions normally inevitably resulting from stirring the reactor.
4. Possibilities to separate reaction products and immobilized particles in the reactor 7 without introducing additinai separation steps.
5. Absence of internals in the filter / concentrator or at least possibilities for a very low volume fraction of internals in the filter concentrator Additionally, it is noted that the technology according to the present invention will result in a 5 lattice of volume elements containing high particle concentrations (node lines and / or node regions) and volume elements containing low particle concentrations.
Also, it is noted that an increase of the number of fluid side channels equipped with acoustic sound generating means is equivalent to applying a lower number of fluid side channels equipped with acoustic sound generating means at a higher acoustic sound frequency.
10 Hence, a design parameter is obtained to realize the desired reactor performance at any desired frequency of the acoustic waves. This may be important since some particles (e.g., bacteria) or particle aggregates are destroyed at their resonant frequency. From this reasoning, it is concluded that, if desired, the technology according to the present invention can be designed such that the particles are destroyed. Also, it can be ensured that no 15 particles are destroyed in the first cilindrical or rectangular fluid channel.
Finally it is noted that the lattice of node regions results in a much better distribution of the particles over the fluid volume in the first cilindrical or rectangular fluid channel. This may be an important advantage above prior art technology in case the first cilindrical or rectangular fluid channel is used as a sensor at the same time. A non limiting example of such 20 advantage is the application of a first cilindrical or rectangular fluid channel as a particle suspension device and coax sensor at the same time. In this particular case, homegeneously distributed particles over the fluid within the first cilindrical fluid channel will result in an effective dielectric permittivity of the particle suspension that hardly changes as a function of the length coordinate of the first cilindrical or rectangular fluid channel. As a 25 result, the properties and / or volume fraction of particles within the coax sensor can be determined from the resonant frequency of the coaxial stub.
Based upon these advantages above prior art, a person skilled in the art will recognize that the technology according to the present invention is very feasible for realizing reliable and fully automated catalysis reactors, crystallizers or bioreactors. Also, a person skilled in the 30 art will recognize that the technology according to the present invention can be applied to other active particles suspended in a fluid.
The present invention is not limited to the above described example embodiments thereof; the rights sought are defined by the following claims, within the scope of which many modifications can be envisaged.
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Clauses 1. Device for a heterogeneous reactor without internals comprising • at least one first fluid channel with a fluid inlet and a fluid outlet 5 «at least a second fluid side channel both connected to the first cilindrical or rectangular fluid channel whereby the angle between the first fluid channel and the second fluid side channel is more than 5 degrees.
• acoustic wave generating means connected to at least the second fluid side channel, the acoustic wave generating means being capable to produce 10 wave interference in at least the first fluid channel • control means for controlling the wave generating means capable to achieve a structure with the generated waves such that at least two node lines or node regions are formed in the first fluid channel as a result of wave interference whereby a significant angle of at least 5 degrees exists between 15 at least two node lines or node regions and the axial direction of the first cilindrical or rectangular fluid channel, resulting in particle being trapped in and / or near the node lines or node regions.
2. Device according to clause 1 further comprising at least a microprocessor and software to control the acoustic wave generating means thereby steering the particle 20 concentration and / or filtration process.
3. Device according to clauses 1 or 2 further comprising at least one sensor for sensing the fluid properties of the first cilindrical or rectangular fluid channel and a control loop to tune the acoustic sound generating means in order to achieve a desired particle filtration and / or concentration performance.
25 4. Crystallizer according to one of the previous clauses 1-3.
5. Bioreactor according to one of the previous clauses 1-3.
6. Catalysis reactor according to one of the previous clauses 1-3.
7. Method for a heterogeneous reactor characterized by a device described by one of the previous clauses 1-6.
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