# US 10,441,938 B2 · Fluid flow continuous physical or chemical processes using dean vortices

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- Number: US 10,441,938 B2
- Document ID: US10441938B2
- Status: Granted
- Kind: B2
- Application number: 14/434,689
- Filed: 2013-10-11
- Published: 2015-10-01
- Granted: 2019-10-15
- Earliest claimed: 2012-10-12
- Assignees: Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO
- Applicants: Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO
- Inventors: Cornelis Petrus Marcus Roelands; Axel Sebastiaan Lexmond; Earl Lawrence Vincent Goetheer; Leonard Ferdinand Gerard Geers
- Web page: https://patentgrep.com/patent/US10441938B2

## CPC

- B01J 19/2405: {provoking a turbulent flow of the reactants, such as in cyclones, or having a high Reynolds-number}
- B01F 25/4331: {Mixers with bended, curved, coiled, wounded mixing tubes or comprising elements for bending the flow}
- B01J 19/1831: {spirally, concentrically or zigzag wound}
- B01J 19/185: {of the pulsating type}
- B01J 19/241: {of the pulsating type}
- B01J 19/243: {spirally, concentrically or zigzag wound}
- B01J 2219/00162: controlling the pressure
- B01J 2219/00164: controlling the flow
- B01J 2219/00166: controlling the residence time inside the reactor vessel
- B01J 2219/24: Stationary reactors without moving elements inside
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06)

## Abstract

The invention is directed to a method for carrying out a continuous physical or chemical process, in particular crystallization. The method of the invention comprises: comprising—flowing a fluid through a channel comprising an inlet and an outlet for said fluid, wherein said channel is at least in part curved and comprises at least two curvatures,—allowing said process to occur at least in part in said fluid in the presence of Dean vortices in said fluid, while—reversing the direction of the flow of said fluid in said channel multiple times, wherein Dean vortices in the fluid in the channel are maintained while the flow is reversed.

## Claims

### Claim 1

Method for carrying out a continuous physical or chemical process comprising the steps of:
i) flowing a fluid through a channel comprising an inlet and an outlet for said fluid, wherein said channel is at least in part curved and comprises at least two curvatures,
ii) allowing said process to occur at least in part in said fluid in the presence of Dean vortices in said fluid, while
iii) reversing the direction of the flow of said fluid in said channel multiple times, wherein Dean vortices in the fluid in the channel are maintained while the flow is reversed, and
repeating step iii) at least once in the continuous process,
wherein during reversal,
relaxation time as defined by Tν is greater than reversal time as defined by Tf, both measured in seconds, whereby (fd2/ν)>1,
f=1/Tf where Tf is a period in seconds where the fluid has a volumetric flow rate of less than 25% of a mean volumetric flow rate of the fluid, and the mean volumetric flow rate is per time period between two reversals of the direction of the flow,
d is the internal diameter of the channel measured in meters, and
ν is the kinematic viscosity of the fluid in meters2/second.

### Claim 2 (depends on 1)

Method according to claim 1, wherein the Dean vortices in the fluid are maintained by reversing the direction of the flow of said fluid in said channel such that that the Dean number De of the flow of the fluid is 10 or more for 90% or more of the time.

### Claim 3 (depends on 1)

Method according to claim 1, wherein a step of reversing the direction of the flow comprises the consecutive steps of: reducing the flow rate, reversing the flow and increasing the flow rate of said fluid in said channel, such that the fraction of the time wherein the fluid has a volumetric flow rate of less than 25% of the mean volumetric flow rate of the fluid per time period between two reversals of the direction of the flow is less than 10%.

### Claim 4 (depends on 3)

Method according to claim 3, wherein the time period between two reversals of the direction of the flow comprises a step wherein the flow rate is essentially constant, and the ratio of the duration of a step wherein the flow rate is essentially constant and the duration of a step of reversing the direction of the flow is 5:1 or more.

### Claim 5 (depends on 1)

Method according to claim 1, wherein said process comprises a multiphase reaction.

### Claim 6 (depends on 1)

Method according to claim 1, wherein said process comprises crystallization of a liquid compound or of a compound dissolved in said fluid.

### Claim 7 (depends on 1)

Method according to claim 1, wherein said reversing the direction of the flow of said fluid in said channel comprises changing the direction of the flow along the channel pathway whereby said fluid is flown through the channel by a combination of a first constant flow and a second oscillatory flow.

### Claim 8 (depends on 1)

Method according to claim 1, wherein the direction of the flow is reversed each 60 seconds or less.

### Claim 9 (depends on 1)

Method according to claim 1, wherein the direction of the flow is reversed by applying high pressure at one end of the channel or low pressure at another end of the channel.

### Claim 10 (depends on 1)

Method according to claim 1, wherein said fluid is flowed alternately in the backward and forward direction in the channel, wherein a period wherein said fluid is flowed in the axial direction of the channel from inlet to outlet for the fluid in the channel is a forward flow step and a period wherein said fluid is flowed in the axial direction of the channel from outlet to inlet for the fluid in the channel is a backward flow step, wherein the channel comprises a helical tubular channel with a plurality of turns, and wherein the fluid flows forward through 0.1-100 turns in a forward flow step.

### Claim 11 (depends on 10)

Method according to claim 10, wherein the fluid flows forward through 1-25 turns in a forward flow step and wherein the ratio between displaced fluid volume in a forward flow step and the displaced fluid volume in a backward flow step is more than 1.

### Claim 12 (depends on 1)

Method according to claim 1, wherein the distance obtained by dividing the displaced fluid volume of a forward flow step by the cross-sectional area of the channel, moved by the fluid in the channel in a forward flow step is 10 times or more the inner diameter of the channel, wherein the channel has a constant cross-sectional area and inner diameter.

### Claim 13 (depends on 1)

Method according to claim 1, wherein the flow of the fluid has a Dean number De of less than 3000.

### Claim 14 (depends on 1)

Method according to claim 1 carried out in an apparatus, comprising
a channel for flowing a fluid through said channel, wherein said channel is at least in part curved and comprises at least two curvatures, and
one or more pulsating units for reversing the flow of said fluid in said channel, wherein said channel comprises a helical tube with a plurality of turns, wherein said plurality of turns is 2-10,000 turns, wherein said helical tube is a circular helix tube,
wherein said channel is axially curved over 50% or more by length of the channel, and
wherein Di/D is 0.01 or more, wherein Di is the inner diameter of said channel and D is the diameter of curvature of said channel.

### Claim 15 (depends on 1)

Method according to claim 1, wherein the fluid has a laminar flow field with laminar mixing.

### Claim 16 (depends on 1)

Method according to claim 1, wherein the fluid is flowed with a shear rate of 1-100 s−1.

### Claim 17 (depends on 1)

Method according to claim 1, wherein the physical or chemical process comprises crystallization or recrystallization of a fat compound.

### Claim 18 (depends on 5)

Method according to claim 5, wherein said multiphase reaction involves one or more selected from the group consisting of crystallization, heterogeneous catalysis, phase transfer catalysis, emulsion polymerization, hydrogenation, oxidation and hydroformylation.

### Claim 19 (depends on 6)

Method according of claim 6, wherein the direction of the flow is reversed 10 or more times during passage of fluid through the channel or during the physical or chemical process.

### Claim 20 (depends on 19)

Method according of claim 19, wherein the direction of the flow is reversed 50 or more times during passage of fluid through the channel or during the physical or chemical process.

### Claim 21 (depends on 20)

Method according of claim 20 wherein the direction of the flow is reversed 100-10,000 times during passage of fluid through the channel or during the physical or chemical process.

### Claim 22 (depends on 8)

Method according to claim 8, wherein the direction of the flow is reversed each 30 seconds or less.

### Claim 23 (depends on 22)

Method according to claim 22, wherein the direction of the flow is reversed each 0.1-10 seconds.