WO2016097045A1

WO2016097045A1 - Flow distributor for numbering-up micro- and milli- channel reactors

Info

Publication number: WO2016097045A1
Application number: PCT/EP2015/080084
Authority: WO
Inventors: Ma'moun Ibrahim Mohammad AL-RAWASHDEH; Dipnarain BINDRABAN; Tjeerd Alexander NIJHUIS; Jacob Cornelis Schouten
Original assignee: Technische Universiteit Eindhoven
Priority date: 2014-12-17
Filing date: 2015-12-16
Publication date: 2016-06-23

Abstract

Numbering-up for micro- and milli- scale fluidic reactors is provided for liquid-liquid and gas-liquid operation. The flow distributor is configured as an array of modular blocks having barrier plates removably clamped to them. The barrier plates include the barrier channels that are used to control fluid flow. The present approach is also applicable for regulating flows from a single fluid input.

Description

Flow distributor for numbering-up micro- and milli- channel reactors

by

FIELD OF THE INVENTION

This invention relates to fluidic reactors.

BACKGROUND

For some applications it is desirable to have two- phase flow (i.e., both liquid flow and gas flow) in

reactors for carrying out chemical reactions. However, conventional approaches for providing two-phase reactors for such applications tend to suffer from significant disadvantages, such as inability to scale effectively for industrial production. This scaling difficulty is

especially acute in cases where the individual flow

channels need to be relatively small, thereby requiring numerous small channels for scaling to industrial

production (as opposed to scaling to production levels by simply increasing the channel size) .

SUMMARY

In this work, scalable two-phase reactors are

provided. The basic design concept is to make use of a modular block architecture combined with easily removable barrier plates to control flow and/or mixing. Although a significant motivation for this work is to address the two- phase mixing problem identified above, the resulting reactor architectures are also suitable for liquid-liquid reactions, and for single phase reaction.

In an exemplary embodiment, the reactor includes two or more modular blocks. Each modular block includes a first fluid distribution volume within the modular block, a second fluid distribution volume within the modular block, and at least one barrier plate having fluidic channels disposed in the barrier plate. The barrier plate is configured to be removably clamped to the modular block to make fluidic connections between the fluidic channels and the first fluid distribution volume, and between the fluidic channels and the second fluid distribution volume. The fluidic channels of the barrier plate can be configured to provide a combined fluidic output when the barrier plate is clamped to the modular block. Alternatively, the fluidic channels of the barrier plate can be configured to provide regulated fluidic outputs when the barrier plate is clamped to the modular block. In this second case, a separate mixer unit can be employed to combine the first and second fluids.

The reactor also includes a first fluid distribution network having a single first fluid input and providing first fluid to the first fluid distribution volume of each of the modular blocks and a second fluid distribution network having a single second fluid input and providing second fluid to the second fluid distribution volume of each of the modular blocks . The modular blocks are configured as a close packed array of rectangular modular blocks. Here a first surface of the array includes all fluidic outputs from the array, and a second surface of the array opposite the first surface is where the modular blocks are mechanically supported.

The first fluid can be a gas and the second fluid can be a liquid (or vice versa) . Alternatively, the first and second fluids can both be liquids.

In preferred embodiments, the barrier plates are clamped to the modular blocks using clamp plates, one clamp plate corresponding to each barrier plate. The area of such clamping is preferably substantially less than the area of the barrier plate. This clamping area is the sealing area that includes all the inlet and outlet holes from the fluidic channels in the barrier plate and the fluidic channels in the modular block. The remaining area in the barrier plate has the remaining length of the fluidic channels in the barrier plate, but need not be clamped to the modular block because no fluidic inputs or outputs are disposed there. Having a relatively small sealing area facilitates sealing with a simple clamp arrangement and can ensure 100% sealing. The alternative and less preferred approach would be a large mechanical sealing block to clamp over the entire area of the barrier plates .

Preferably, as described in greater detail below, the design is such that dead zones within the reactor are minimized. More specifically, it is preferred that distances between the first surface (i.e., the fluid output surface) and the clamp areas of the barrier plates are each 20 mm or less. This ensures that the channels between the barrier plates and the fluid output surface are relatively short, as desired. Fluidic seals can be used to control fluidic

connections made by clamping the barrier plates to the rectangular modular blocks. These fluidic seals can include O-rings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGs. 1A-B is a schematic representation of a barrier- based flow distributor for four parallel microchannels .

FIG. 2A is a side view of several rectangular modular distribution units in a first embodiment of the invention.

FIG. 2B is an enlarged view of the elements of one of the rectangular distributor units of FIG. 2A.

FIG. 2C is a further enlarged view of FIG. 2B showing fluid flows .

FIG. 2D is a further enlarged view of FIG. 2C showing fluidic seals .

FIG. 3 is a top view of the embodiment of FIGs. 2A-D.

FIGs . 4A-B show stacked modular units for the

embodiment of FIGs . 2A-D.

FIG. 5A is a side view of several rectangular modular distribution units in a second embodiment of the invention.

FIG. 5B is an enlarged view of the elements of one of the rectangular distributor units of FIG. 5A.

FIG. 5C is a further enlarged view of FIG. 5B showing fluid flows.

FIG. 5D is a further enlarged view of FIG. 5C showing fluidic seals.

FIG. 6 is a top view of the embodiment of FIGs . 5A-D . FIGs . 7A-B show stacked modular units for the embodiment of FIGs . 5A-D .

FIG . 8A is a side view of several rectangular modular distribution units in a third embodiment of the invention.

FIG . 8B is an enlarged view of the elements of one of the rectangular distributor units of FIG . 8A.

FIG . 8C is a further enlarged view of FIG . 8B showing fluid flows.

DETAILED DESCRIPTION

The flow capacity of micro- and milli- reactor technology is determined by the concept used for scale-up and the phases involved in the reaction. For single gas phase reaction, micro- and milli- reactor technology used the concept of numbering-up to thousands of parallel channels that made it possible to reach flow capacity larger than 1000 ton/year and in the range of 10000 ton- year which is relevant for wide range of industrial applications. Numbering-up increases the flow capacity by placing multiple reactor channels in parallel, this can ranges from few channels up to thousands of channels like in the single gas phase reaction.

In conventional liquid phase and two-phase flow applications, numbering-up is usually minimal and flow capacity is increased instead by scaling-up the single channel cross section dimensions. This is compensated by: (1) enhancing the mixing and heating by passive mixers created by the microstructure geometry made in the micro and milli channel reactor and (2) increasing the flow rate to enhance mixing and heating in the microchannel . This approach works but it has limitations. First, it has a limit to its flow capacity to a range of 1000 to 5000 ton/year or less. Second, it does not always work because some applications require the micro- and milli- scale dimensions. For example, the generation of small stabilised gas droplets, mono dispersed emulsion and mono sized nano particle synthesis is one such application. Thus, the micro and milli channel dimensions can be essential for the product functionality.

Thus the concept of numbering-up has not

conventionally been utilized as much for liquid phase flow and for multiphase flow as for gas flow. Furthermore, the micro- and milli- reactor technology for multiphase and liquid flow has limited flow capacity due to the challenge of flow distribution in these cases.

For micro- and milli- channel reactors, there are six important conditions to impose on a liquid phase or multiphase flow distributor.

1) Provide the required flow uniformity.

The desired flow uniformity should be reached because it is crucial for product quality. Additionally, flow channelling should be prevented.

2) Manifolds volume with respect to reactor channels volume .

The micro- and milli- channel reactor is a very compact reactor with small reaction channel volume. The main advantage of the micro- and milli- channel reactor is the low liquid retention which is important for safety to handle highly exothermic, toxic and/or aggressive chemical reactions. That is why the distributor needs to be compact and the volume of the manifold in the distributor needs to be similar or smaller than the volume of the reaction channels .

3) No dead zone in the distributor and easy to clean.

The micro- and milli- channels reactors are a type of reactor that should be made modular and multipurpose as it competes with batch reactors. Thus, the distributor needs to be easy to clean and have no dead zones . Otherwise complications arise when switching from one product to another since the new product will contain traces of the previous product.

4) Flow leak tight.

Typically, micro- and milli- channel reactors are

subdivided into parts that need to be assembled together. This division allows reactor modularity and increases its flexibility to handle a variety of reaction conditions . For numbering-up, one of these modular parts is the distributor which can then be combined to different types of reaction channels. The sealing for assembling these modular parts is important and in many cases decides the operating window of the reactor. Some conventional designs have mechanical size dominated by the features used to provide leak-tight fluidic seals, which is clearly undesirable.

5) Material resistance to aggressive chemicals and

thermally stable The multipurpose use of the reactor and the range of its operating window depend on the choice of material of construction. Thus, a distributor which can be fabricated from a variety of materials is a very attractive solution. Additionally, the distributor needs to be stable when applying high temperatures and pressure. So it should accommodate thermal expansion.

6) Manufacturing cost, flexibility, and modularity.

Since the distributor should be suited for large scale manufacturing, the manufacturing cost is of crucial importance for the commercial viability of the distributor.

The present approach provides uniform mixed gas-liquid or liquid-liquid output flow streams. This approach makes it possible to number-up two-phase or liquid-liquid flow to reach flow capacity larger than 1000 ton/year.

The concept of the flow distribution of this apparatus is the insertion of micro scale channels named barrier channels between the reaction channels and the manifold of the distributor. FIGs . 1Ά-Β show an example. Here 102 is the first fluid distribution network, 104 is the second fluid distribution network, 106 is a T-mixer (one for each channel) , and 108 is a reaction channel (one for each channel) . Barrier channels 110 control flow between 102 and 106 and barrier channels 112 control flow between 104 and 106

The dimensions of the barrier channels and the fabrication accuracy regulate the flow distribution and determine its flow uniformity in a passive way without a need for sensors and active control valves . It is modular and can be assembled to varied reaction channel geometries, material of constructions and dimensions. This is a significant advantage compared to typical flow distributors which are designed for specific reactor design and

dimensions .

Significant further aspects of the present approach relate to implementation details. The system assembly of the following description fulfils all of the above- identified six conditions for a multiphase or liquid-liquid flow distributor or for single phase flow distributor for micro- and milli- channel reactors. Functional elements of the apparatus combine together to create a synergistic effect that provides an optimal flow distributor for solving the numbering-up challenge for multi-phase and liquid-liquid and single phase flow applications.

The implementation of the reactor can be summarized as a modular block approach having clampable barrier plates to provide the barrier channels. Fig. 2A-D show an example. In this example, 202 and 204 are the first and second fluid distribution networks, respectively, and are shown

schematically for simplicity. The reactor includes several modular blocks, one of which is referenced as 206. The outputs 208 from each modular block in this example are combined from the inputs. For example, if one of the inputs is a gas and the other input is a liquid, the output is two-phase gas-liquid, as schematically shown by the dash-dotted lines. As shown on FIG. 2B, barrier plates 210a and 210b are clamped to the top and bottom of modular block 206 by clamping plates 212a and 212b respectively. Modular block 206 includes first fluid distribution volume 214 and second fluid distribution volume 216. Fluid in first fluid distribution volume 214 is provided by first fluid distribution network 202. Fluid in second fluid distribution volume 216 is provided by second fluid distribution network 204.

FIG. 2C schematically shows the fluid flows for this example. Barrier plates 210a and 210b are configured to provide combined outputs from their inputs, as shown.

FIG. 2D shows further detail, where barrier channel 218 in barrier plate 210a is configured as a T-mixer to provide a combined output. In this example, fluidic seals 220 (e.g., O-rings) are shown between barrier plate 210a and modular block 206. The barrier plate is where the barrier channels are fabricated. These barrier channels are the one that regulate the flow distribution. The barrier plates are segmented into separate plates that are connected to the modular blocks. The barrier plates are preferably connected to the top and bottom of each modular block as shown. The barrier plates are preferably clamped individually to the modular block using individual clamping surface plates. 0- rings are placed on the opening of the fluidic channels to and from the modular block. Each clamping plate presses its own barrier plate to the modular block which seals the fluidic channels. Fluidic channel openings to and from the modular block and barrier plate are preferably localized on a rectangular sealing area lower than surface area of the barrier plate, as shown.

The sealing area and clamping plate are preferably located in the direction of the edge of the outlet streams from the modular block within a distance less than 20 mm. The sealing of the all the inlet and outlet channels openings from the barrier plate occurred on a small and compact sealing area near to the outlet streams from the modular block within a distance of less than 20 mm. This distance is important for minimizing the volume of transport channels, the compactness of the distributor, manufacturing accuracy and fabrication cost.

The barrier channels are fabricated on individual and separated barrier plates . Barrier plates are individually clamped and sealed on the modular block. The fabrication of the barrier channels on separate barrier plates allows significant improvement in the local fabrication accuracy of the barrier channels which are crucial for flow

uniformity. This fulfils reaching uniform flow and prevents channelling. For example, the fabrication precision in the barrier channels might need to be ±1μπι that requires strict and advanced fabrication technologies like wet chemical etching. This strict fabrication precision can be reached much more easily in a small barrier plate surface area that is rectangular with a dimension of 35 mm x 85 mm, more preferably to 25mm x 65mm, and more preferably to 15 mm x to 45 mm. Additionally, fabricating the barrier channels into separate plates allows using components made from different materials. Such segmentation leads to a reduced fabrication cost of the final distributor and more

importantly the possibility to reach the target fabrication precision and flow distribution.

The localized closing of barrier plates using clamping plate on its flow inlet and outlet streams allows equal distribution of the sealing force over the O-rings assuring the connection is leak-tight over a broad range of

operating conditions of temperature and pressure. So the barrier plate will be leak tight and will not break because of unbalanced closing force. The small dimensions of the sealing area allow using a flat clamping system which is small and does not occupy space thereby providing

compactness of the distributor which is important for micro- and milli- reactor design. Tightening the barrier plate from one side of the barrier plate only makes it easy for the barrier plate to thermally expand with minimum stresses. Different materials can be used to fabricate the modular distributor blocks and the barrier plates making this design suitable for aggressive chemicals. The barrier plates can be replaced easily which is desirable for example to replace a defective channel and/or to provide additional flow distribution capacity. Furthermore, the barrier plates can be fabricated relatively easily due to the small barrier plate dimensions.

FIG. 3 shows a top view of a modular block 206 having several barrier plates (one of which is referenced as 210a) and several clamp plates, one of which is referenced as 212a.

FIGs . 4A-B show two side views of several modular blocks as on FIG. 3 stacked on top of each other. These blocks are referenced as 206a, 206b and 206c. An important feature of this arrangement is that all of the fluid outputs come from surface 406 of the array of modular blocks. This means that the opposite surface (i.e., surface 404) can be used to provide mechanical support for the array of modular blocks. In this example, the array is shown affixed to mechanical support member 402.

In this first example, mixing of the two inputs is provided by the barrier plates. It is also possible for the barrier plates to not provide mixing. Instead they can be used exclusively to control flow, and mixing, if desired, can take place in an optional separate unit.

FIGs. 5A-7B show an example of this embodiment. In this example, 202 and 204 are the first and second fluid distribution networks, respectively, and are shown

schematically for simplicity. The reactor includes several modular blocks, one of which is referenced as 206. The outputs 502 from each modular block in this example are regulated outputs that are separate for each input. For example, if one of the inputs is a gas and the other input is a liquid, the outputs are separate gas and liquid outputs, as schematically shown by the solid and dashed lines. As shown on FIG. 5B, barrier plates 510a and 510b are clamped to the top and bottom of modular block 206 by clamping plates 212a and 212b respectively. Modular block 206 includes first fluid distribution volume 214 and second fluid distribution volume 216. Fluid in first fluid distribution volume 214 is provided by first fluid

distribution network 202. Fluid in second fluid

distribution volume 216 is provided by second fluid distribution network 204.

FIG. 5C schematically shows the fluid flows for this example. Barrier plates 510a and 510b are configured to provide separate regulated outputs from their inputs, as shown. FIG. 5D shows further detail, where barrier channels 518 and 520 in barrier plate 510a are configured to provide separate outputs. In this example, fluidic seals 522 (e.g., O-rings) are shown between barrier plate 510a and modular block 206. Preferred embodiments for this example are as indicated above in connection with

FIGs . 2A-D .

FIG. 6 shows a top view of a modular block 206 having several barrier plates (one of which is referenced as 510a) and several clamp plates, one of which is referenced as 212a. Here 602 is an optional mixer to receive the regulated outputs and mix them.

FIGs. 7A-B show two side views of several modular blocks as on FIG. 6 stacked on top of each other. These blocks are referenced as 206a, 206b and 206c. An important feature of this arrangement is that all of the fluid outputs come from surface 406 of the array of modular blocks. This means that the opposite surface (i.e., surface 404) can be used to provide mechanical support for the array of modular blocks. In this example, the array is shown affixed to support member 402.

As indicated above, the reactor is configured as an array of modular blocks. These blocks are stacked on top of each other (e.g., as on FIGs . 4A-B) . The modular block contains two fluid distribution volumes which are

fabricated inside the modular block. Each distribution volume distributes its contents to a number of outlet streams with equal uniform flow rates, as regulated by the barrier channels in the barrier plates. These outlet streams can be separate or combined. The outlet flows leave via one side of the modular block only. This is the modular block side which can be used to connect the distributor to parallel reaction channels with varied design dimensions and materials. The opposite side of the distributor can be used to mechanically hold all the rectangular modular blocks (e.g., as shown on FIG. 4B) . The other two sides of the distributor can be used to feed the rectangular modular blocks (single phase distributing manifolds) and for cleaning and circulation of the flow in these modular blocks. The top and bottom part of each rectangular modular block can be used to connect the barrier chips where the barrier channels are fabricated.

The inputs can be mixed in the fluidic channels disposed in the barrier plate or in a mixing modular block (e.g., 602 on FIG. 6) . This mixing unit can be disposed on the first surface of the modular block array which includes all regulated outputs. In cases where mixing is not done in the barrier plates, the barrier plates are used to regulate the flow distribution so that required flow uniformity is provided.

The geometrical assembly of the apparatus allow easy replacement of different micro and milli reaction channel geometries, dimensions and material of constructions using the same inlet flow distributor. The flow range of the distributor can vary significantly depending on the dimensions of the internal barrier channels in the barrier plate. The flow capacity of the distributor can be easily increased by stacking the modular blocks on top of each to form an array of blocks (e.g., as shown on FIGs. 4A-B) while all channels experience the same flow and pressure. The main limitation foreseen on how many modules can be stacked is how many barrier plates can be fabricated with the required fabrication precision.

Each modular block combines different components in a way that produces modular, compact, and minimized manifold distribution volumes. This can be made possible by

arranging the single phase manifold distribution volumes to be enclosed in each other via 3D printing technique. This made the network of inlet and outlet transport channels in the modular block easily fabricated and connected to the barrier plates in a compact and smaller volume space. The modular block has two inlet/outlet tubes connected to each manifold distribution volume to quickly empty the

distributor and clean it and as well eliminate any flow dead zones.

The present approach enables the micro- and milli- reactor for multi phase reactions to reach industrial flow capacity larger than 1000 tons-year and to a capacity like 10000 tons/year. The preceding examples have considered reactors having two inputs whose flow is to be controlled and optionally mixed. This modular reactor approach is also applicable to reactors having a single input whose flow is to be

controlled.

FIGs . 8A-C show an example of this embodiment. In this example, there is only one fluid distribution network, referenced as 204. The reactor includes several modular blocks, one of which is referenced as 806. The outputs 802 from each modular block in this example are regulated outputs. As shown on FIG . 8B, barrier plates 810a and 810b are clamped to the top and bottom of modular block 806 by clamping plates 212a and 212b respectively. Modular block 806 includes a fluid distribution volume 216. Fluid in fluid distribution volume 216 is provided by fluid

distribution network 204. FIG . 5C schematically shows the fluid flows for this example. Barrier plates 810a and 810b are configured to provide regulated outputs from their inputs, as shown.

Claims

1. Apparatus for providing a mixed fluid output, the apparatus comprising:

a) a plurality of rectangular modular blocks, wherein each rectangular modular block includes:

a first fluid distribution volume within the

rectangular modular block;

a second fluid distribution volume within the

rectangular modular block; and

one or more barrier plates having fluidic channels disposed in the barrier plate;

wherein the barrier plates are configured to be removably clamped to the rectangular modular block to make fluidic connections between the fluidic channels and the first fluid distribution volume, and between the fluidic channels and the second fluid distribution volume, and

wherein the fluidic channels of the barrier plates are configured to provide a mixed fluidic output when the barrier plates are clamped to the modular block;

b) a first fluid distribution network having a single first fluid input and providing first fluid to the first fluid distribution volume of each of the rectangular modular blocks; and

c) a second fluid distribution network having a single second fluid input and providing second fluid to the second fluid distribution volume of each of the rectangular modular blocks;

wherein the rectangular modular blocks are configured as a close packed array of rectangular modular blocks, wherein a first surface of the array includes all mixed outputs from the array, and wherein the array is configured to be mechanically supported at a second surface of the array opposite the first surface.

2. The apparatus of claim 1, further comprising a clamp plate corresponding to each barrier plate, wherein each clamp plate is configured to individually clamp its corresponding barrier plate to the rectangular modular block.

3. The apparatus of claim 2, wherein each barrier plate is clamped to the rectangular modular block in a clamp area that is substantially less than an area of the barrier plate.

4. The apparatus of claim 3, wherein distances between the first surface and the clamp areas of the barrier plates are each 20 mm or less.

5. The apparatus of claim 1, further comprising fluidic seals to control fluidic connections made by clamping the barrier plates to the rectangular modular blocks.

6. The apparatus of claim 5, wherein the fluidic seals comprise O-rings.

7. The apparatus of claim 1, wherein one of the first fluid and the second fluid is a gas and the other of the first fluid and the second fluid is a liquid, whereby two-phase mixing is provided.

8. Apparatus for providing a regulated fluid output, the apparatus comprising:

a) a plurality of rectangular modular blocks, wherein each modular block includes:

a first fluid distribution volume within the

rectangular modular block; and

wherein the barrier plates are configured to be removably clamped to the rectangular modular block to make fluidic connections between the fluidic channels and the first fluid distribution volume, and

wherein the fluidic channels of the barrier plates are configured to provide regulated fluidic outputs when the barrier plates are clamped to the rectangular modular block;

b) a first fluid distribution network having a single first fluid input and providing first fluid to the first fluid distribution volume of each of the rectangular modular blocks;

wherein the rectangular modular blocks are configured as a close packed array of rectangular modular blocks, wherein a first surface of the array includes all regulated fluidic outputs from the array, and wherein the array is configured to be mechanically supported at a second surface of the array opposite the first surface.

9. The apparatus of claim 8,

wherein each of the modular blocks further includes a second fluid distribution volume within the rectangular modular block,

wherein the barrier plates are configured to make fluidic connections between the fluidic channels and the second fluid distribution volume, and further comprising: c) a second fluid distribution network having a single second fluid input and providing second fluid to the second fluid distribution volume of each of the rectangular modular blocks .

10. The apparatus of claim 9, further comprising a mixing unit configured to receive the regulated fluidic outputs and configured to provide a mixed fluidic output by combining the regulated fluidic outputs .

11. The apparatus of claim 9, wherein one of the first fluid and the second fluid is a gas and the other of the first fluid and the second fluid is a liquid.

12. The apparatus of claim 8, further comprising a clamp plate corresponding to each barrier plate, wherein each clamp plate is configured to individually clamp its corresponding barrier plate to the rectangular modular block .

13. The apparatus of claim 12, wherein each barrier plate is clamped to the rectangular modular block in a clamp area that is substantially less than an area of the barrier plate .

14. The apparatus of claim 13, wherein distances between the first surface and the clamp areas of the barrier plates are each 20 mm or less.

15. The apparatus of claim 8, further comprising fluidic seals to control fluidic connections made by clamping the barrier plates to the rectangular modular blocks.

16. The apparatus of claim 15, wherein the fluidic seals comprise O-rings.