6.1 Mixing Equipment. Fig. 6.1 A standard tank with a working volume of 100 M 3 and used for penicillin production

Size: px
Start display at page:

Download "6.1 Mixing Equipment. Fig. 6.1 A standard tank with a working volume of 100 M 3 and used for penicillin production"

Transcription

1 Chapter 6 Mixing Mixing, a physical process which aims at reducing non-uniformities in fluids by eliminating gradients of concentration, temperature, and other properties, is happening within every bioreactor. It is so important that, in a very large extend, decides the performance of a bioreactor. When mixing is beneficial to bioprocesses, for example, the contact of substrate and other nutrients to cells during cell culture, we should try to improve the mixing performance of a bioreactor through all kinds of means. Otherwise, we should avoid its negative effects. 1

2 6.1 Mixing Equipment Fig. 6.1 A standard tank with a working volume of 100 M 3 and used for penicillin production 2

3 Fig. 6.2 Typical configuration of a stirred tank 3

4 Fig. 6.3 Baffle arrangements 4

5 Fig. 6.4 Impeller designs 5

6 Impeller type Fig. 6.5 Viscosity ranges for different impellers 6 Viscosity (centipoise) Anchors propellers Flat-blade turbines paddles Gate anchors Helical screws Helical ribbons 1

7 6.2 Flow Patterns Developed in Agitated Tanks Fig. 6.6 Circular flow in a unbaffled stirred tank 7

8 6.2.1 Radial-flow impeller Fig. 6.7 Flow pattern produced by a radial-flow impeller in a baffled tank 8

9 6.2.2 Axial-flow impeller Fig. 6.8 Pitched-blade turbine 9

10 Fig 6.9 Flow pattern produced by an axial-flow impeller in a baffled tank 10

11 6.3 Mechanism of Mixing As illustrated before, large liquid-circulation loops developed in stirred vessels make mixing performance poor. For mixing to be effective, fluid circulated by the impeller must sweep the entire vessel in a reasonable time. In addition, the velocity of fluid leaving the impeller must be sufficient to carry material into the most remote parts of the tank. Turbulence must also be developed in the fluid; mixing is certain to be poor unless flow in the tank is turbulent. All these factors are important in mixing, which can be described as a combination of three physical processes: distribution, dispersion and diffusion. 11

12 Fig 6.10 Flow pattern developed by a radial-flow impeller 12

13 The process whereby materials are transported to all regions of the vessel by bulk circulation currents is called distribution. Distribution is an important process in mixing, but can be relatively slow. In large tank, the size of the circulation paths is also large and the time taken to traverse them is long; this, together with the regularity of liquid pumping at the impeller, inhibits rapid mixing. Accordingly, distribution is often the slowest step in the mixing process. However, if the rotational speed of the impeller is sufficiently high, superimposed on the distribution process is turbulence. Turbulence flow occurs when fluid no longer travels along streamlines but moves erratically in the form of cross-currents. 13

14 The kinetic energy of turbulent fluid is directed into regions of rotational flow called eddies; masses of eddies of various size coexist during turbulent flow. Large eddies are continuously formed by action of the stirrer; these break down into small eddies which produce even smaller eddies. Eddies, like spinning tops, posses kinetic energy. When the eddies become so small that they can no longer sustain rotational motion, their kinetic energy is dissipated as heat. The process of breaking up bulk flow into smaller and smaller eddies is called dispersion; dispersion facilitates rapid transfer of material throughout the vessel. The degree of homogeneity as a result of dispersion is limited by the size of the smallest eddies which may be formed in a particular fluid. 14

15 This size is given approximately as the Kolmogorov scale of mixing, or scale of turbulence, λ. λ = ( 3 ν ) 1/4 p m (6.1) Within eddies there is little mixing because rotating flow occurs in streamlines. Therefore, to achieve mixing on a scale smaller than the Kolmogorov scale, we must rely on diffusion. Molecular diffusion is generally regarded as a slow process, however, over small distances it can be accomplished quite rapidly. Within eddies of 30~100 μm diameter, homogeneity is achieved in about 1 s for low-viscosity fluids. Consequently, if power input to a stirred vessel produces eddies of this dimension, mixing on a molecular scale is accomplished virtually simultaneously.. 15

16 6.4 Assessing Mixing Effectiveness Mixing time is a useful parameter for assessing mixing efficiency and is applied to characterize bulk flow in fermenters. The mixing time t m is the time required to achieve a given degree of homogeneity starting from the completely segregated state. It can be measured by injecting a tracer into the vessel and following its concentration at a fixed point in the tank. Tracers in common use include acids, bases and concentrated salt solutions; corresponding detectors are ph probes and conductivity cells. Mixing time can also be determined by measuring the temperature response after addition of a small quantity of heated liquid. 16

17 Let us assume a small pulse of tracer is added to fluid in a stirred tank already containing tracer material at concentration C i. When flow in the system is circulation, the tracer concentration measured at some fixed point in the tank will follow a pattern similar to that shown in Figure Before mixing is complete, a relatively high concentration will be detected every time the bulk flow brings tracer to the measurement point. The peaks in concentration will be separated by a period approximately equal to the average time taken for fluid to traverse one bulk circulation loop. In stirred tank this period is called the circulation time t c. After several circulations the desired degree of homogeneity is reached. 17

18 C t c Tracer concentration C f 0.1(C - C ) f i C i Time t m t Fig Concentration response after tracer is injected into a stirred tank 18

19 Definition of the mixing time t m depends on the degree of homogeneity required. Usually, mixing time is defined as the time after which the concentration of tracer differs from the finial concentration C f by less than 10% of the total concentration difference (C f C i ). At t m the tracer concentration is relatively steady and the fluid composition approaches uniformity. For a single-phase liquid in a stirred tank with several baffles and small impeller, there is an approximate relationship between mixing time and circulation time t m = 4t c (6.2) 19

20 We can predict that mixing time in stirred tanks will depend on variables such as the size of the tank and impeller, fluid properties such as viscosity, and stirred speed. The relationship between mixing time and several of these variables has been determined experimentally for different impellers; results for a Rushton turbine in a baffled tank are shown in Fig The dimensionless number N i t m is plotted as a function of the impeller Reynolds number (Re) i. t m is the mixing time based on a 10% deviation from final conditions, and N i is rotational speed of the stirrer. N i t m represents the number of stirrer rotations required to homogenize the liquid. 20

21 Fig 6.12 Variation of mixing time with Reynolds number for a six-blade Rushton turbine in a baffled tank 21

22 At low Reynolds number, N i t m increases significantly with decrease of (Re) i. However, as Reynolds number is increased above about , N i t m approaches a constant value which persists at high (Re) i. For Rushton turbines, this constant value can be estimated using the following relationship. N i t m = (Re) i = 1. 54V 3 D i 2 N i D i ρ μ (6.3) (6.4) 22

23 Example 6.1 Estimation of mixing time A fermentation broth with viscosity 10 2 Pa s and density 1000 kg m 3 is agitated in a 2.7 m 3 baffled tank using a Rushton turbine with diameter 0.5 m and stirred speed 1 s 1. Estimate the mixing time. Solution: From Eq.(6.4): (Re) i = (Re) i > , therefore N i t m is constant and can be calculated from Eq.(6.3): N i t m = 33.3 Therefore: t m = 33.3/1 = 33.3 s 23

24 6.5 Power Requirements for Mixing Usually, electrical power is used to drive impellers in stirred tanks. For a given stirred speed, the power required depends on the resistance offered by the fluid to rotation of the impeller. Average power consumption per unit volume for industrial bioreactors ranges from 10 kw m 3 for small vessels to 1~2 kw m 3 for large vessels. Friction in the stirrer motor gearbox and seals reduces the energy transmitted to the fluid; therefore, the electrical power consumed by stirrer motors is always greater than the mixing power by an amount depending on the efficiency of the drive. Energy costs for operation of stirrers in bioreactors are an important consideration in process economics. 24

25 6.5.1 Ungassed Newtonian Fluids Mixing power for non-aerated fluids depends on the stirrer speed, the impeller diameter and geometry, and properties of the fluid such as density and viscosity. The relationship between these variables is usually expressed in terms of dimensionless numbers such as the impeller Reynolds number (Re) i and the power number N p. N p is defined as: and N p = P 3 ρn i D i 5 (6.5) P = N p ρn i 3 D i 5 (6.6) 25

26 Fig Correlation between power number and Reynolds number for Rushton turbine, paddle and marine propeller without sparging 26

27 Fig 6.14 Correlation between power number and Reynolds number for anchor and helical-ribbon impeller without sparging 27

28 Laminar region: The laminar regime corresponds to (Re) i < 10 for many impellers; for stirrers with very small wall-clearance such as the anchor and helical-ribbon mixer, laminar flow persists until (Re) i = 100 or greater. In the laminar regime: or N p 1/(Re) i P = k 1 μn i2 D i 3 (6.7) Turbulent regime: Power number is independent of Reynolds number in turbulent flow. Therefore: P = N p ρn i3 D i 5 (6.8) 28

29 Table 6.1 Constants in Eq.(6.7) and (6.8) Impeller type k 1, (Re) i = 1 N p, (Re) i = 10 5 Rushton turbine 70 5~6 Paddle 35 2 Marine propeller Anchor Helical ribbon

30 N p for turbines is significantly higher than for most other impellers, indicating that turbines transmit more power to the fluid than other designs. Power required for turbulent flow is independent of the viscosity of the fluid but proportional to fluid density. The turbulent regime is fully developed at (Re) i > 10 3 or 10 4 for most small impellers in baffled vessels. Transition regime: Between laminar and turbulent flow lies the transition regime. Both density and viscosity affect power requirements in this regime. There is usually a gradual transition from laminar to fully-developed turbulent flow in stirred tanks; the flow pattern and Reynolds-number range for transition depend on system geometry. 30

31 Eqs.(6.7) and (6.8) express the strong dependence of power consumption on stirrer diameter and, to a lesser extent, stirrer speed. Small changes in impeller size have a large effect on power requirements, as would be expected from dependency on impeller diameter raised to the third or fifth power. In the turbulent regime, a 10% increase in impeller diameter increases the power required by more than 60%; a 10% increase in stirrer speed rasies the power required by over 30%. 31

32 Example 6.2 Calculation of power requirements A fermentation broth with viscosity 10 2 Pa s and density 1000 kg m 3 is agitated in a 50 m 3 baffled tank using a marine propeller 1.3 m in diameter. The tank geometry is as specified in Figure Calculate the power required for a stirred speed of 4 s 1. Solution: From Eq.(6.4): (Re) i = = From Figure 6.13, flow at this (Re) i is fully turbulent and N p = 0.35 Therefore: P = = kgm 2 s 3 = 83 kw 32

33 6.5.2 Ungassed Non-Newtonian Fluids Impeller Reynolds number based on the apparent viscosity μ a : (Re) i = N i D i μ a 2 For stirred tanks, an approximate relation for pseudoplastic fluids is often used: Substituting Eq.(6.11) into (6.10) gives: ρ (6.9) For power-law fluids: 2 N i D i ρ (Re) i = n K γ r 1 (6.10) γ = kn (6.11) i (Re) i = N 2 n i K k 2 i n-1 D ρ (6.12) 33

34 N P P = ρn 3 5 i D i 50 Newtonian Non-Newtonian (Re) i = ρn i D i μ 2 or ρn i D i μ a 2 Fig Correlation between power number and Renolds number for a Rushton turbine in unaerated fluids 34

35 6.5.3 Gassed Fluids All of the changes in hydrodynamic behavior duo to gassing are not completely understood. Power consumption is strongly controlled by gas-cavities formation; because this process is discontinuous and appears somewhat randomly, reduction in power consumption is typically non-uniform. The random nature of gas dispersion in agitated tanks means that it is difficult to obtain an accurate prediction of power requirements. However, an expression for the ratio of gassed to ungassed power as a function of operating conditions has been obtained. 35

36 p P g 0 = Fg 0.10( N V i ) i N D ( gw V i 4 i 2 / 3 ) 0.20 (6.13) Fig Gas cavities formed behind the blades of a 7.6 cm nine-blade fat-disc turbine in water sparged with air 36

37 6.6 Scale-up of Mixing Systems Design of industrial-scale bioprocess is usually based on the performance of small-scale prototypes. Determining optimum operating conditions at production scale is expensive and timeconsuming; accordingly, it is always better to know whether a particular process will work properly before it is constructed in full size. Ideally, scale-up should be carried out so that conditions in the large vessels are as close as possible to those producing good results in the small vessels. As mixing is an important function of bioreactors, it would seem desirable to keep the mixing time constant on scale-up. Unfortunately, as explained below, the relationship between mixing time and power consumption makes 37

38 this rarely possible in practice. As the volume of mixing vessels is increased, so too are the lengths of the flow paths for bulk circulation. To keep the mixing time constant, the velocity of fluid in the tank must be increased in proportion to the size. As a rough guide, under turbulent conditions the power per unit volume is proportional to the fluid velocity squared: P/V v 2 (6.14) Suppose a cylindrical 1 m 3 pilot-scale stirred tank is scaled up to 100 m 3. If the tanks are geometrically similar, the length of the flow path in the large tank is about 4.5 times that in the small one. Therefore, to keep the same mixing time, fluid velocity in the large tank must be approximately 4.5 times faster. From Eq.(6.14) this would entail a or 20-fold increase in power 38

39 per unit volume. So, if the power input to the 1 m 3 pilot-scale vessel is P, the power required for the same mixing time in the 100 m 3 tank is about 2000 P. This represents an extremely large increase in power, much greater than is economically or technically feasible with most equipment used for stirring. Because the criterion of constant mixing time can hardly ever be applied for scale-up, it is inevitable that mixing time increase with scale. If instead of mixing time, P/V is kept constant during scaleup, mixing time can be expressed to increase in proportion to vessel diameter raised to the power Reduced productivity and performance often accompany scale-up of bioreactors as a result of lower mixing efficiency and subsequent alteration of the physical environment. One way of improving the design procedure is to use scale-down methods. 39

40 The general idea behind scale-down is that small-scale experiments to determine operating parameters are carried out under conditions that can actually be realized, physical and economically, at production scale. For example, if we decide that power input to a large-scale vessel cannot exceed a certain limit, we can calculate the corresponding mixing time and use an appropriate power input to a small-scale bioreactor to stimulate mixing conditions in the large-scale system. With this approach, as long as the flow regime is the same in the small- and large-scale fermenters, there is a better chance that results achieved in the small-scale unit will be reproducible in the larger system. 40

41 6.7 Improving Mixing in Fermenters Sometimes, it is impossible to reduce mixing time by simply raising the power input. So, while increasing the stirrer speed is an obvious way of improving fluid circulation, other techniques may be required. Mixing can be improved by changing the configuration of bioreactors. Baffles should be installed; this is routine for stirrer fermenters and produces greater turbulence. For efficient mixing the impeller should be mounted below the geometric center of the vessel. In standard designs the impeller is located about one impeller diameter, or one-third the tank diameter, above the bottom of the tank. 41

42 Mixing is facilitated when circulation currents below the impeller are smaller than those above; fluid particles leaving the impeller at the same time instant then take different periods of time to return and exchange material. Rate of distribution throughout the vessel is increased when upper and lower circulation loops are asynchronous. Another device for improving mixing is multiple impellers, although this requires an increase in power input. Typical bioreactors used for aerobic culture are tall cylindrical vessels with liquid depths significantly greater than the tank diameter. This design produces a higher hydrostatic pressure at the bottom of the vessel, and gives rising air bubbles a longer contact time with liquid. Effective mixing in tall fermenters requires more than one impeller. 42

43 Fig Multiple impellers in a tall fermenter 43

44 In ungassed systems with spacing between impellers of at least one impeller diameter, the power dissipated by multiple impellers is approximated by the following relationship: P n = np s (6.15) Additional mixing problems can appear in fermenters when material is fed into system during operation. If bulk distribution is slow, fermenters operated continuously or in fed-batch mode may develop highly localized concentrations of substrate or other added material near the feed point. 44

45 This has been observed particularly in large-scale processes for production of SCP (single-cell-protein) from methanol. Because high levels of methanol are toxic to cell growth, biomass yields decrease significantly when mixing of feed material into the broth is slow. Also observed was that during animal cell culture when alkali such as NaOH was used to control ph, high local ph value seriously affected the growth of the cells, although experiment was carried out within a small fermenter. Problems like this can be alleviated by using multiple injection points to aid distribution of added material. It is much less expensive to do this than to increase the fluid velocity and power input (grad). 45

46 6.8 Effect of Rheological Properties on Mixing For effective mixing there must be turbulent conditions in the mixing vessel. Intensity of turbulence is represented by the impeller s Reynolds number. As discussed before for a baffled tank with turbine impeller, once (Re) i falls below criteria turbulence is damped and mixing time increases significantly. (Re) i decreases in direct proportion to increase in viscosity. Accordingly, non-turbulent conditions and poor mixing are likely to occur during agitation of highly viscous fluids. Increasing the impeller speed is an obvious solution, but this requires considerable increase in power consumption and therefore may not be feasible. 46

47 Most non-newtonian fluids in bioprocessing are pseudoplastic. Because the apparent viscosity of these fluids depends on the shear rate, the rheological behavior of many culture broths depends on shear conditions in the fermenters. Pseoduplastic fluids are shear thinning, i.e. their apparent viscosity decreases with increasing shear. Accordingly, in stirred vessels, pseudoplastic fluids have relatively low apparent viscosity in the high-shear zone near the impeller, and relatively high apparent viscosity when the fluid is away from the impeller. As a result, flow patterns similar to that illustrated below can develop. 47

48 Stagnant zones Fig Mixing pattern for pseudoplastic in a stirred tank 48

49 The effects of local fluid thinning in pseudoplastic fluids can be countered by modifying the geometry of the system or impeller design. Stirrers of large diameter are recommended. For turbine impellers, instead of the usual tank-to-impeller diameter ratio of 3:1 used with low viscosity fluids, this ratio is reduced to between 1.6 ~ 2.0. Different impeller designs which sweep the entire volume of the vessel are also recommended. The most common types used for viscous mixing are helical impellers and gate- and paddle-anchors mounted with small clearance between the impeller and tank wall. Mixing with these stirrers is accomplished at low speed without highvelocity streams. Helical agitators have been successfully used to reduce shear damage and improve mixing in viscous cell suspensions. 49

50 Alternative impeller designs such as the helical ribbon and anchor improve mixing in viscous fluids; however their application in fermentaters is only possible when oxygen demand in culture is relatively low. Although large-diameter impellers operating at relatively slow speed give superior bulk mixing, high-shear systems with small, high-speed impellers are preferable for breaking up gas bubbles and promoting oxygen transfer to the liquid. in design of fermenters for viscous cultures, a compromise is usually required between mixing effectiveness and adequate mass transfer (undergrad). 50

51 6.9 Role of Shear in Stirred Tank Mixing in bioreactors must provide the shear conditions necessary to disperse bubbles, droplets and cell flocs. Dispersion of gas bubbles by agitation involves a balance between opposing forces. Shear forces in turbulent eddies stretch and distort the bubbles and break them into small sizes; at the same time, surface tension at the gas-liquid interface tends to restore the bubbles to their spherical shape. In the case of solid material such as cell flocs or aggregates, shear forces in turbulent flow are resisted by the mechanical strength of the particles. While bubbles break-up is required in fermenters to facilitate 51

52 oxygen transfer, disruption of cell is undesirable. Different cell types display different levels of shear sensitivity; insect, mammalian, and plant cells are known to be particularly sensitive to mechanical forces. Bioreacters used for culture for those cells must limit the intensity of shear while still providing adequate mixing and mass transfer. At the present time, the effects of shear on cells are not well understood. Cell disruption is an obvious outcome of high shear forces; however more subtle changes such as retardation of growth and product synthesis, denaturation of extracellular proteins, change in morphology, and thinning of the cell wall, may also occur. Because there is significant spatial variation in shear 52

53 intensity in stirred vessels, the precise shear conditions experienced by cells are poorly defined. There have been many publications addressing the problem of shear damage, especially in insect- and mammalian-cell cultures. Several mechanisms have been considered in terms of their contribution to cell damage: Interaction between cells and turbulent eddies; Collision between cells, collision of cells with the impeller, and collision of cells with stationary surfaces in the vessel; Generation of shear forces in the boundary layers and wakes near solid objects in the reactor, especially the impeller; 53

54 Generation of shear forces as bubbles rise through liquid; and Bursting of bubbles at the liquid surface. In general, when gas bubbles are not present in the liquid, interactions between cells and turbulent eddies are considered most likely to damage cells. However, if the vessel is sparged with air, shear damage can occur at much lower impeller speeds due to shear effects associated with bubbles. 54

55 6.9.1 Interaction Between Cells and Eddies Hydrodynamic effects have been studied mainly with animal cells because shear damage is a significant problem in large-scale culture. Many animal cells used in bioprocessing are anchoragedependent; this means that the cells must be attached to a solid surface for survial. In bioreactors, the surface area required for cell attachment is provided very effectively by microcarrier beads, which range in diameter from 80 ~ 200 μm. Cells cover the surface of the beads which are then suspended in nutrient medium. 55

56 Fig Chinese hamster ovary (CHO) cells attached to microcarriers 56

57 There are many benefits associated with the use of microcarriers; however, a disadvantage is that cells attached to microcarriers cannot easily change position or rotate in response to shear forces in the fluid. This, coulped with the lack of a protective cell wall, make animal cells on microcarriers especially susceptible to shear damage. Interactions between microcarriers and eddies in turbulent flow have the potential to cause mechanical damage to cells. The intensity of shear associated with these interactions is dependent on the relative sizes of the eddies and microcarriers. If the particles are small relative to the eddies, they tend to be captured or entrained in the eddies as shown below. 57

58 (a) (b) Eddy streamlines Microcarrier paths Microcarrier Microcarrier Eddy streamlines High shear zone Fig Eddy-microcarrier interactions 58

59 As fluid motion within eddies is laminar, if the density of the microcarriers is about the same as the suspending fluid, there is little relative motion of the particles. Accordingly, the velocity difference between the fluid streamlines and the microcarriers is small, except for brief periods of acceleration when the bead enters a new eddy. On average, therefore, if the particles are smaller than the eddies, the shear effects of eddy-cell interactions are minimal. If the stirred speed is increased and the average eddy size reduced, interactions between eddies and microcarriers can occur in two possible ways. A single eddy that cannot fully engulf the particle will act on part of its surface and cause the particle to rotate in the fluid; 59

60 this will result in a relatively small level of shear at the surface of the bead. However, much higher shear stress result when several eddies with opposing rotation interact with the particle simultaneously. It has been found experimentally that detrimental effects start to occur when the Kolmogorov scale for eddy size drops below 2/3 ~ 1/2 the diameter of the microcarrier beads. Excessive agitation leads to formation of eddies with size small enough and of sufficient energy to cause damage to the cells. These findings for cell on microcarroers apply also to freely suspended cells; however, because cells are smaller than microcarriers, eddy size causing shear damage are also small. 60

61 Example 6.3 Operating conditions for turbulent shear damage Microcarrier beads 120 μm in diameter are used to culture recombinant CHO cells for hormone production. It is proposed to use a 6-cm turbine impeller to mix the culture in a 3.5 liter stirred tank. Air and carbon dioxide are supplied by flow through the bioreactor headspace. The microcarrier suspension has a density of approximately 1010 kg m 3 and a viscosity of Pa s. Estimate the maximum allowable stirrer speed which avoids turbulent shear damage of the cells. 61

62 Solution: Damage due to eddies is avoided if the Kolmogorov scale remains greater than 2/3 ~ 1/2 the diameter of the beads. Let us determine the stirrer speed required to create eddies with size λ = 2/3 120 = 80 μm = m. The stirrer power producing eddies of this dimension can be calculated: p m = ν λ 3 4 = ( ( ) 4 ) 3 = m 2 s -3 where ν = μ ρ = = m s 62

63 Fluid mass in the impeller zone is roughly equal to ρd i3 where ρ is fluid density and D i is impeller diameter. Therefore, the stirrer power P is equal to p m multiplied by ρd i3 : P = ( ) 3 = kg m 2 s 3 = W N p is about 5 for a turbine impeller operating in the turbulent regime, depending on the geometry of the tank. The stirrer speed corresponding to these conditions can be calculated: N i 3 = P ' N p ρd i 5 = ( ) 5 = 2.89 s -3 63

64 N i = 1.42 s 1 = 85.5 rpm Flow is just turbulent with (Re) i = This analysis indicates that shear damage from turbulent eddies is not expected until the stirrer speed exceeds about 85 rpm. If the culture were sparged with gas, it is possible that shear damage would happen due to other mechanisms, e.g. bursting bubbles. If the viscosity of the liquid is increased, the size of the smallest eddies also increases. Increasing the fluid viscosity should, therefore, reduce shear damage in bioreactors. This effect has been demonstrated by addition of thickening agents to animal-cell growth medium; moderate increase in viscosity have been shown to significantly reduce turbulent cell death. 64

65 6.9.2 Bubble Shear When liquid containing shear-sensitive cells is sparged with air, other damaging mechanisms come into play. From experiments conducted so far, these appear to be associated primarily with bubbles bursting at the surface of the liquid, breakage of the thin bubble film and rapid flow from the bubble rim back into the liquid generate high shear forces capable of damaging certain types of cell. 65

66 Summary After the study of this chapter, you should be: familiar with equipment used for mixing in stirred tanks; able to describe the mechanisms of mixing and their effect on mixing time; able to understand the effects of scale-up on mixing; able to know how liquid properties, gas sparging, impeller size and stirrer speed affect power consumption in stirred vessels; and able to understand how cells can be damaged by shear in stirred fermenters. 66

CHAPTER 2 CULTURE TYPE

CHAPTER 2 CULTURE TYPE CHAPTER 2 CULTURE TYPE All types of micro-organisms are grown in suspension with the exception of cell culture, in which cells can also be anchorage dependent. Suspension the micro-organism can grow successfully

More information

DEVELOPMENTS IN IMPELLER TECHNOLOGY FOR MIXING VISCOUS, NON-NEWTONIAN FLUIDS. Richard K. Grenville Director of Mixing Technology

DEVELOPMENTS IN IMPELLER TECHNOLOGY FOR MIXING VISCOUS, NON-NEWTONIAN FLUIDS. Richard K. Grenville Director of Mixing Technology DEVELOPMENTS IN IMPELLER TECHNOLOGY FOR MIXING VISCOUS, NON-NEWTONIAN FLUIDS Richard K. Grenville Director of Mixing Technology ASC Convention Atlanta Marriott Marquis, Atlanta GA 5 th April 2017 TOPICS

More information

Scale-up & scale-down between the two. worlds of shaken and stirred bioreactors

Scale-up & scale-down between the two. worlds of shaken and stirred bioreactors Scale-up & scale-down between the two worlds of shaken and stirred bioreactors Prof. Dr.-Ing. Jochen Büchs AVT - Biochemical Engineering, RWTH Aachen University Sammelbau Biologie, D - 52074 Aachen, Germany

More information

Chapter 7 Mass Transfer

Chapter 7 Mass Transfer Chapter 7 Mass Transfer Mass transfer occurs in mixtures containing local concentration variation. For example, when dye is dropped into a cup of water, mass-transfer processes are responsible for the

More information

MIXING IMPACT ON ANTISOLVENT CRYSTALLIZATIONS. Dr. Wayne Genck Genck International

MIXING IMPACT ON ANTISOLVENT CRYSTALLIZATIONS. Dr. Wayne Genck Genck International MIXING IMPACT ON ANTISOLVENT CRYSTALLIZATIONS Dr. Wayne Genck Genck International Agitator Parameters Table 1. Agitator Parameters Agitator Type N P N Q (Q/P) R PBT Hydrofoil Rushton GL Retreat Blade*

More information

Romanian Biotechnological Letters Vol. 14, No. 5, 2009, pp Romanian Society of Biological Sciences ORIGINAL PAPER

Romanian Biotechnological Letters Vol. 14, No. 5, 2009, pp Romanian Society of Biological Sciences ORIGINAL PAPER Romanian Biotechnological Letters Vol. 14, No. 5, 9, pp. 4681-4693 Copyright 9 University of Bucharest Printed in Romania. All rights reserved Romanian Society of Biological Sciences ORIGINAL PAPER Comparative

More information

Scalability of the Mobius CellReady Single-use Bioreactor Systems

Scalability of the Mobius CellReady Single-use Bioreactor Systems Application Note Scalability of the Mobius CellReady Single-use Bioreactor Systems Abstract The Mobius CellReady single-use bioreactor systems are designed for mammalian cell growth and recombinant protein

More information

BIOREACTOR ENGINEERING Chapter 8. Faculty of Chemical & Natural Resources Engineering Bioreactor/Fermenter Systems by Chew Few Ne

BIOREACTOR ENGINEERING Chapter 8. Faculty of Chemical & Natural Resources Engineering Bioreactor/Fermenter Systems by Chew Few Ne BIOREACTOR ENGINEERING Chapter 8 Bioreactor/Fermenter Systems by Chew Few Ne Faculty of Chemical & Natural Resources Engineering cfne@ump.edu.my Chapter Description Topic Outcome Classify types of bioreactor/fermenter

More information

Bioreactor System ERT 314. Sidang /2012

Bioreactor System ERT 314. Sidang /2012 Bioreactor System ERT 314 Sidang 1 2011/2012 Chapter 3:Types of Bioreactors Week 4-5 Handouts : Chapter 13 in Doran, Bioprocess Engineering Principles Background to Bioreactors The bioreactor is the heart

More information

BCT Loop Reactor Technology

BCT Loop Reactor Technology BCT Loop Reactor Technology By BUSS ChemTech AG www.buss-ct.com Hohenrainstrasse 10 CH-4133 Pratteln 1, Switzerland Tel. + 41 (0) 618 256 462 Fax. +41 (0) 618 256 737 Abstract This paper highlights the

More information

GENERAL PROCESS CONSIDERATIONS IN THE SELECTION OF AGITATORS FOR SIMPLE APPLICATIONS AND IMPELLER DESIGN.

GENERAL PROCESS CONSIDERATIONS IN THE SELECTION OF AGITATORS FOR SIMPLE APPLICATIONS AND IMPELLER DESIGN. GENERAL PROCESS CONSIDERATIONS IN THE SELECTION OF AGITATORS FOR SIMPLE APPLICATIONS AND IMPELLER DESIGN. The first thing to keep in mind is proper positioning of the agitator with respect to the vessel

More information

Comparison of Impeller-Baffle Interactions in Alumina Precipitators

Comparison of Impeller-Baffle Interactions in Alumina Precipitators Comparison of Impeller-Baffle Interactions in Alumina Precipitators Abstract René Rödenbeck, Detlef Klatt, Janin Klatt-Eberle Project Engineer Managing Director General Manager STC-Engineering GmbH, Waldenburg,

More information

3.2: MIXING OF SOLIDS NOOR MUHAMMAD SYAHRIN BIN YAHYA

3.2: MIXING OF SOLIDS NOOR MUHAMMAD SYAHRIN BIN YAHYA 3.2: MIXING OF SOLIDS NOOR MUHAMMAD SYAHRIN BIN YAHYA The mixing of solids, whether free flowing or cohesive resembles to some extent the mixing of low-viscosity liquids. Both processes inter-mingle two

More information

VISIMIX TURBULENT. LIQUID - LIQUID MIXING. DROP SIZE. SCALING UP.

VISIMIX TURBULENT. LIQUID - LIQUID MIXING. DROP SIZE. SCALING UP. VISIMIX TURBULENT. LIQUID - LIQUID MIXING. DROP SIZE. SCALING UP. In mixing of immiscible liquids, two rivaling processes of break-up and coalescence of drops occur simultaneously. The intensity of both

More information

Scale-up in Bioprocess Sandip Bankar and Tero Eerikainen

Scale-up in Bioprocess Sandip Bankar and Tero Eerikainen Scale-up in Bioprocess and Tero Eerikainen sandip.bankar@aalto.fi CONTROL OF BIOPROCESS SANDIP BANKAR AND TERO EERIKAINEN sandip.bankar@aalto.fi https://www.sartorius.com/en/products/bioreactors-fermentors/single-use/biostat-str/

More information

Contents. Preface XI Nomenclature XIII. Part I Basic Concepts and Principles 1

Contents. Preface XI Nomenclature XIII. Part I Basic Concepts and Principles 1 V Preface XI Nomenclature XIII Part I Basic Concepts and Principles 1 1 Introduction 3 1.1 Background and Scope 3 1.2 Dimensions and Units 4 1.3 Intensive and Extensive Properties 6 1.4 Equilibria and

More information

Modern Dispersion Technology (cover)

Modern Dispersion Technology (cover) Morehouse Cowles Disperser Basics Proudly Represented by: Divtech Equipment Co PO Box 58468 Cincinnati, OH 45258 513-941-0483 info@divtechequipment.com Modern Dispersion Technology (cover) Primary Forces

More information

Presenter: Suprvisor: Selection, Scale up and Operation of Bioreactors

Presenter: Suprvisor: Selection, Scale up and Operation of Bioreactors In the Name of God Presenter: Maryam Shahmansouri Suprvisor: Dr.Reza Gheshlaghi Selection, Scale up and Operation of Bioreactors (Chapter 10 Shuler) 1 Outline types of Bioreactors problems in large reactors

More information

PREPARED BY: DR. RAHIMAH OTHMAN FOOD ENGINEERING (ERT 426) SEMESTER 1 ACADEMIC SESSION 2016/17

PREPARED BY: DR. RAHIMAH OTHMAN FOOD ENGINEERING (ERT 426) SEMESTER 1 ACADEMIC SESSION 2016/17 1 PREPARED BY: DR. RAHIMAH OTHMAN FOOD ENGINEERING (ERT 426) SEMESTER 1 ACADEMIC SESSION 2016/17 SUBTOPICS 2 1. Introduction 2. Basic Principles of Extrusion 3. Extrusion System 3.1 Cold Extrusion 3.2

More information

Dr. J. Wolters. FZJ-ZAT-379 January Forschungszentrum Jülich GmbH, FZJ

Dr. J. Wolters. FZJ-ZAT-379 January Forschungszentrum Jülich GmbH, FZJ Forschungszentrum Jülich GmbH, FZJ ZAT-Report FZJ-ZAT-379 January 2003 Benchmark Activity on Natural Convection Heat Transfer Enhancement in Mercury with Gas Injection authors Dr. J. Wolters abstract A

More information

MANGANESE REMOVAL FROM COBALT SOLUTIONS WITH DILUTE SULPHUR DIOXIDE GAS MIXTURES

MANGANESE REMOVAL FROM COBALT SOLUTIONS WITH DILUTE SULPHUR DIOXIDE GAS MIXTURES MANGANESE REMOVAL FROM COBALT SOLUTIONS WITH DILUTE SULPHUR DIOXIDE GAS MIXTURES J van Rooyen, S. Archer and M. Fox Senior Process Engineer TWP Matomo Process Plant P.O. Box 5100 Rivonia, 2128 Senior Process

More information

TECHNICAL PAPER. Stirred Bioreactor Engineering for Production Scale, Low Viscosity Aerobic Fermentations: Part 1. By: Dr.

TECHNICAL PAPER. Stirred Bioreactor Engineering for Production Scale, Low Viscosity Aerobic Fermentations: Part 1. By: Dr. TECHNICAL PAPER Stirred Bioreactor Engineering for Production Scale, Low Viscosity Aerobic Fermentations: Part 1 By: Dr. Alvin Nienow Senior Technical Consultant The Merrick Consultancy Merrick & Company

More information

PROVISIONAL PATENT APPLICATION NS306. Method for Establishing Self-Lubricated Flow of Bitumen Froth or Heavy Oil in a Pipeline

PROVISIONAL PATENT APPLICATION NS306. Method for Establishing Self-Lubricated Flow of Bitumen Froth or Heavy Oil in a Pipeline PROVISIONAL PATENT APPLICATION NS306 Method for Establishing Self-Lubricated Flow of Bitumen Froth or Heavy Oil in a Pipeline D.D. Joseph *, R. Bai *, O. Neiman à, K. Sury à, C. Grant à Background When

More information

2.4 TYPES OF MICROBIAL CULTURE

2.4 TYPES OF MICROBIAL CULTURE 2.4 TYPES OF MICROBIAL CULTURE Microbial culture processes can be carried out in different ways. There are three models of fermentation used in industrial applications: batch, continuous and fed batch

More information

Tribology Module4: Lubricants & Lubrication

Tribology Module4: Lubricants & Lubrication Tribology Module4: Lubricants & Lubrication Q.1. What is fluid film lubrication? What is the difference between hydrostatic and hydrodynamic lubrication? Ans: Fluid film lubrication is a generic term used

More information

1. Overview of Fermentation Technology

1. Overview of Fermentation Technology 1. Overview of Fermentation Technology The word fermentation comes from the LATIN term ferver which means to boil. It is actually referred as the physical state of boiling process. The bubbling appearance

More information

Laboratory Testing of Safety Relief Valves

Laboratory Testing of Safety Relief Valves Laboratory Testing of Safety Relief Valves Thomas Kegel (tkegel@ceesi.com) and William Johansen (bjohansen@ceesi.com) Colorado Engineering Experiment Station, Inc. (CEESI) 5443 WCR 37, Nunn, Colorado 8648

More information

Design optimization of a bioreactor for ethanol production using CFD simulation and genetic algorithms

Design optimization of a bioreactor for ethanol production using CFD simulation and genetic algorithms Computational Methods and Experimental Measurements XV 67 Design optimization of a bioreactor for ethanol production using CFD simulation and genetic algorithms E. R. C. Góis & P. Seleghim Jr. Thermal

More information

CFD simulations of RTD of a strawberry pulp in a continuous ohmic heater

CFD simulations of RTD of a strawberry pulp in a continuous ohmic heater CFD simulations of RTD of a strawberry pulp in a continuous ohmic heater I. Castro, N. Reis, J.A. Teixeira, A. A. Vicente 1 Centro de Engenharia Biológica, Universidade do Minho, Campus de Gualtar, 4710-057

More information

Evaluation and Modeling of the Aerobic Stirred Bioreactor Performances for Fungus Broths

Evaluation and Modeling of the Aerobic Stirred Bioreactor Performances for Fungus Broths A.-I. GALACTION et al., Evaluation and Modeling of the Aerobic Stirred, Chem. Biochem. Eng. Q. 19 (1) 87 97 (2005) 87 Evaluation and Modeling of the Aerobic Stirred Bioreactor Performances for Fungus Broths

More information

Improving the performance of mechanical stirring in biogas plant by computational fluid dynamics (CFD)

Improving the performance of mechanical stirring in biogas plant by computational fluid dynamics (CFD) December, 2017 AgricEngInt: CIGR Journal Open access at http://www.cigrjournal.org Vol. 19, No. 4 91 Improving the performance of mechanical stirring in biogas plant by computational fluid dynamics (CFD)

More information

Effect of Impeller Clearance and Liquid Level on Critical Impeller Speed in an Agitated Vessel using Different Axial and Radial Impellers

Effect of Impeller Clearance and Liquid Level on Critical Impeller Speed in an Agitated Vessel using Different Axial and Radial Impellers Journal of Applied Fluid Mechanics, Vol. 9, No. 6, pp. 2753-2761, 2016. Available online at www.jafmonline.net, ISSN 1735-3572, EISSN 1735-3645. Effect of Impeller Clearance and Liquid Level on Critical

More information

Pfenex : A Fermentation Platform based on Pseudomonas fluorescens

Pfenex : A Fermentation Platform based on Pseudomonas fluorescens Pfenex : A Fermentation Platform based on Pseudomonas fluorescens Deisy Corredor, PhD. Upstream Group Leader Global Bio-Production Summit Feb 6 th - 2018 Outline Fermentation Process Development Scale-Up

More information

MEASUREMENT OF CAVERN SIZES AND SHAPE IN AGITATED YIELD STRESS AQUEOUS SOLUTIONS WITH AN ELECTROCHEMICAL PROBE

MEASUREMENT OF CAVERN SIZES AND SHAPE IN AGITATED YIELD STRESS AQUEOUS SOLUTIONS WITH AN ELECTROCHEMICAL PROBE 14 th European Conference on Mixing Warszawa, 1-13 September 212 MEASUREMENT OF CAVERN SIZES AND SHAPE IN AGITATED YIELD STRESS AQUEOUS SOLUTIONS WITH AN ELECTROCHEMICAL PROBE Takaya Nagafune a, Yushi

More information

Bioreactors and Fermenters. Biometrix Corporation (800)

Bioreactors and Fermenters. Biometrix Corporation (800) Bioreactors and Fermenters Biometrix Corporation (800)-890-89 1 Course Objectives This lesson will discuss bioreactors including basic operations, typical instrumentation configurations and calibration

More information

DETERMINATION OF DROP BREAKAGE MECHANISMS BY EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF SINGLE DROP BREAKAGES

DETERMINATION OF DROP BREAKAGE MECHANISMS BY EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF SINGLE DROP BREAKAGES 14 th European Conference on Mixing Warszawa, 1-13 September 212 DETERMINATION OF DROP BREAKAGE MECHANISMS BY EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF SINGLE DROP BREAKAGES S. Nachtigall a, D. Zedel

More information

Kelly B. Fox, Drilling Specialties Company; Carl E. Stouffer, Drilling Specialties Company and Beau Utley, Drilling Specialties Company

Kelly B. Fox, Drilling Specialties Company; Carl E. Stouffer, Drilling Specialties Company and Beau Utley, Drilling Specialties Company AADE-8-DF-HO-3 Evaluation Of A New Friction Reducer for Brines Kelly B. Fox, Drilling Specialties Company; Carl E. Stouffer, Drilling Specialties Company and Beau Utley, Drilling Specialties Company Copyright

More information

DEVELOPMENT OF NOVEL DROP DIAMETER MEASURING METHOD IN THE MANUFACTURING PROCESS OF FUNCTIONAL O/W MICROCAPSULES

DEVELOPMENT OF NOVEL DROP DIAMETER MEASURING METHOD IN THE MANUFACTURING PROCESS OF FUNCTIONAL O/W MICROCAPSULES 14 th European Conference on Mixing Warszawa, 10-13 September 2012 DEVELOPMENT OF NOVEL DROP DIAMETER MEASURING METHOD IN THE MANUFACTURING PROCESS OF FUNCTIONAL O/W MICROCAPSULES K. Kanaya a, S. Akao

More information

AN EFFECT OF BLADE GEOMETRY ON HEAT TRANSFER PERFORMANCE IN STIRRED VESSEL COAL WATER SLURRY SYSTEM USING COAL GASIFICATION

AN EFFECT OF BLADE GEOMETRY ON HEAT TRANSFER PERFORMANCE IN STIRRED VESSEL COAL WATER SLURRY SYSTEM USING COAL GASIFICATION AN EFFECT OF BLADE GEOMETRY ON HEAT TRANSFER PERFORMANCE IN STIRRED VESSEL COAL WATER SLURRY SYSTEM USING COAL GASIFICATION C.M.Raguraman 1, A. Ragupathy 2, R. Ramkumar 3, L. Sivakumar 4 1,2 and 3 Department

More information

CHAPTER 1 INTRODUCTION

CHAPTER 1 INTRODUCTION CHAPTER 1 INTRODUCTION Study of combustion process in all combustion systems is one of the most important and complex problems. Generally, the main objective is to achieve a stable combustion proves that

More information

Efficient operation of the HyPerforma 5:1 Single-Use Bioreactor at low working volume

Efficient operation of the HyPerforma 5:1 Single-Use Bioreactor at low working volume APPLICATION NOTE HyPerforma : Single-Use Bioreactor Efficient operation of the HyPerforma : Single-Use Bioreactor at low working volume Introduction The Thermo Scientific HyPerforma : Single-Use Bioreactor

More information

Outline. Upstream Processing: Development & Optimization

Outline. Upstream Processing: Development & Optimization Upstream Processing: Development & Optimization Kamal Rashid, Ph.D., Director Biomanufacturing Education & Training Center Worcester Polytechnic Institute Outline Introduction to Upstream processing Microbial

More information

HKICEAS-660 Liquid-Liquid Dispersion: Effects of Dispersed Phase Viscosity on Mean Drop Size and Distribution in Stirred Vessel

HKICEAS-660 Liquid-Liquid Dispersion: Effects of Dispersed Phase Viscosity on Mean Drop Size and Distribution in Stirred Vessel HKICEAS- Liquid-Liquid Dispersion: Effects of Dispersed Phase Viscosity on Mean Drop Size and Distribution in Stirred Vessel Z. A. Mohd Izzudin Izzat, A. R. Abdul Aziz, M. N. Mohamad Nor Chemical Engineering

More information

a. Sulfite Oxidation (Cooper, Ind. Eng. Chem. 336, 504, 1944)

a. Sulfite Oxidation (Cooper, Ind. Eng. Chem. 336, 504, 1944) 7. Measurement of k L a and OUR a. Sulfite Oxidation (Cooper, Ind. Eng. Chem. 336, 504, 1944) Relies on the rate of conversion of 0.5 M sodium sulfite to sodium sulfate in the presence of cobalt ion catalyst:

More information

EFFECT OF SOLIDS CONCENTRATION ON SOLID-LIQUID MASS TRANSFER IN AN AGITATED DISSOLUTION SYSTEM

EFFECT OF SOLIDS CONCENTRATION ON SOLID-LIQUID MASS TRANSFER IN AN AGITATED DISSOLUTION SYSTEM EFFECT OF SOLIDS CONCENTRATION ON SOLID-LIQUID MASS TRANSFER IN AN AGITATED DISSOLUTION SYSTEM Chongguang Yu¹, Rajarathinam Parthasarathy 1 *, Jie Wu 2 and Dr. Nicky Eshtiaghi 1 1 School of Civil, Environmental

More information

oe4625 Dredge Pumps and Slurry Transport Vaclav Matousek October 13, 2004

oe4625 Dredge Pumps and Slurry Transport Vaclav Matousek October 13, 2004 oe4625 Vaclav Matousek October 13, 2004 1 Dredge Vermelding Pumps onderdeel and Slurry organisatie Transport 3. FLOW OF SOIL-WATER MIXTURE FLOW REGIMES FLOW PATTERNS FLOW QUANTITIES/PARAMETERS October

More information

Evaluating the Use of Airlift Pumps for Bioreactor Applications

Evaluating the Use of Airlift Pumps for Bioreactor Applications Proceedings of the 4 th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'17) Toronto, Canada August 21 23, 2017 Paper No. 134 DOI: 10.11159/ffhmt17.134 Evaluating the Use of Airlift

More information

STRATCO Contactor Reactor. Economic Analysis

STRATCO Contactor Reactor. Economic Analysis No. 0202 STRATCO Contactor Reactor Economic Analysis Presented at the 2002 NLGI Annual Meeting San Diego, California By John Kay and Richard Burkhalter STRATCO, Inc. and Covenant Engineering Services,

More information

Professor Wei-Shou Hu Spring 2007 ChEn 5751

Professor Wei-Shou Hu Spring 2007 ChEn 5751 Professor Wei-Shou Hu Spring 2007 ChEn 5751 Cell Culture Bioreactors Basic Types of Bioreactors................................................... 1 Segregated Bioreactors (Dead Zone Present)\Compartmentalized

More information

AN INTRODUCTION TO FLUIDIZATION BY MILAN CARSKY UNIVERSITY OF KWAZULU-NATAL

AN INTRODUCTION TO FLUIDIZATION BY MILAN CARSKY UNIVERSITY OF KWAZULU-NATAL AN INTRODUCTION TO FLUIDIZATION BY MILAN CARSKY UNIVERSITY OF KWAZULU-NATAL AN INTRODUCTION TO FLUIDIZATION SUMMARY Principle of fluidization (gas-solid fluidization, liquid-solid fluidization, properties

More information

Cells and Cell Cultures

Cells and Cell Cultures Cells and Cell Cultures Beyond pure enzymes, whole cells are used and grown in biotechnological applications for a variety of reasons: cells may perform a desired transformation of a substrate, the cells

More information

INVESTIGATION OF FLUID DYNAMICS IN AN UNBAFFLED STIRRED VESSEL WITH AN ECCENTRICALLY LOCATED RUSHTON TURBINE

INVESTIGATION OF FLUID DYNAMICS IN AN UNBAFFLED STIRRED VESSEL WITH AN ECCENTRICALLY LOCATED RUSHTON TURBINE MATEUSZ MUSIK, JAN TALAGA INVESTIGATION OF FLUID DYNAMICS IN AN UNBAFFLED STIRRED VESSEL WITH AN ECCENTRICALLY LOCATED RUSHTON TURBINE BADANIA HYDRODYNAMIKI MIESZANIA W MIESZALNIKU BEZ PRZEGRÓD Z NIECENTRYCZNIE

More information

CFD: A New Challenge in Bioprocess Engineering

CFD: A New Challenge in Bioprocess Engineering CFD: A New Challenge in Bioprocess Engineering 1 Lilibeth Niño, 1 Mariana Peñuela, 2 Germán Gelves 1 Department of Chemical Engineering, University of Antioquia, Carrera 53 No. 61-30. Medellin, Colombia.

More information

Choice of Test Machines

Choice of Test Machines Choice of Test Machines 2003 George Plint Wear & Failure Mechanisms The more we can characterize the full scale problem the easier it becomes to ensure that the bench tests we run will provide useful information.

More information

Characterization of agitation environments in 250 ml spinner vessel, 3 L, and 20 L reactor vessels used for animal cell microcarrier culture

Characterization of agitation environments in 250 ml spinner vessel, 3 L, and 20 L reactor vessels used for animal cell microcarrier culture Cytotechnology 22: 95??, 1996. 95 c 1996 Kluwer Academic Publishers. Printed in the Netherlands. Special Issue Characterization of agitation environments in 250 ml spinner vessel, 3 L, and 20 L reactor

More information

Oxygen Transfer Performance of Unbaffled Stirred Vessels in View of Their Use as Biochemical Reactors for Animal Cell Growth

Oxygen Transfer Performance of Unbaffled Stirred Vessels in View of Their Use as Biochemical Reactors for Animal Cell Growth A publication of CHEMICA ENGINEERING TRANSACTIONS VO. 27, 2012 Guest Editors: Enrico Bardone, Alberto Brucato, Tajalli Keshavarz Copyright 2012, AIDIC Servizi S.r.l., ISBN 978-88-95608-18-1; ISSN 1974-9791

More information

A MATHEMATICAL MODEL OF META-ARAMID FIBRID FORMATION

A MATHEMATICAL MODEL OF META-ARAMID FIBRID FORMATION THERMAL SCIENCE, Year 2017, Vol. 21, No. 4, pp. 1651-1655 1651 A MATHEMATICAL MODEL OF META-ARAMID FIBRID FORMATION by Li-Rong YAO *, Xiao-Juan LI, Ye-Qun JIANG, and Shan-Qing XU School of Textile and

More information

Fundamentals and Applications of Biofilms Bacterial Biofilm Formation and Culture

Fundamentals and Applications of Biofilms Bacterial Biofilm Formation and Culture 1 Fundamentals and Applications of Biofilms Bacterial Biofilm Formation and Culture Ching-Tsan Huang ( 黃慶璨 ) Office: Agronomy Building, Room 111 Tel: (02) 33664454 E-mail: cthuang@ntu.edu.tw 2 Introduction

More information

Continuous Xylose Fermentation by Candida shehatae in a Two-Stage Reactor

Continuous Xylose Fermentation by Candida shehatae in a Two-Stage Reactor In: Scott, Charles D., ed. Proceedings of the 9th symposium on biotechnology for fuels and chemicals; 1987 May 5-8; Boulder, CO. In: Applied Biochemistry and Biotechnology. Clifton, NJ: Humana Press; 1988:

More information

Precipitation Crystallisation of Poorly Soluble Materials

Precipitation Crystallisation of Poorly Soluble Materials Precipitation Crystallisation of Poorly Soluble Materials Precipitation of Poorly Soluble Materials Kali Umwelttechnik GmbH (K-UTEC) Am Petersenschacht 7 99706 Sondershausen Germany Phone: ++ 49 3632 610-0

More information

Mixing theory for culture and harvest in bioreactors of human mesenchymal stem cells on microcarriers

Mixing theory for culture and harvest in bioreactors of human mesenchymal stem cells on microcarriers Loughborough University Institutional Repository Mixing theory for culture and harvest in bioreactors of human mesenchymal stem cells on microcarriers his item was submitted to Loughborough University's

More information

Bioreactor System ERT 314. Sidang /2011

Bioreactor System ERT 314. Sidang /2011 Bioreactor System ERT 314 Sidang 1 2010/2011 Chapter 2:Types of Bioreactors Week 2 Choosing the Cultivation Method The Choice of Bioreactor Affects Many Aspects of Bioprocessing. Product concentration

More information

CFD Modelling of an Aerosol Exposure Chamber for Medical Studies G. Manenti, M. Derudi, G. Nano, R. Rota

CFD Modelling of an Aerosol Exposure Chamber for Medical Studies G. Manenti, M. Derudi, G. Nano, R. Rota CFD Modelling of an Aerosol Exposure Chamber for Medical Studies G. Manenti, M. Derudi, G. Nano, R. Rota Dip. di Chimica, Materiali e Ingegneria Chimica G. Natta, Politecnico di Milano, via Mancinelli

More information

FLUID-DYNAMICS CHARACTERISTICS OF A VORTEX INGESTING STIRRED TANK FOR THE PRODUCTION OF HYDROGEN FROM ORGANIC WASTES FERMENTATION

FLUID-DYNAMICS CHARACTERISTICS OF A VORTEX INGESTING STIRRED TANK FOR THE PRODUCTION OF HYDROGEN FROM ORGANIC WASTES FERMENTATION 14 th European Conference on Mixing Warszawa, 10-13 September 2012 FLUID-DYNAMICS CHARACTERISTICS OF A VORTEX INGESTING STIRRED TANK FOR THE PRODUCTION OF HYDROGEN FROM ORGANIC WASTES FERMENTATION Alessandro

More information

EFFECT OF INCLINATION ANGLE, DIMENSIONS OF IMPELLER BLADES, AND VELOCITY GRADIENT ON THE EFFICIENCY OF WATER FLOCCULATION

EFFECT OF INCLINATION ANGLE, DIMENSIONS OF IMPELLER BLADES, AND VELOCITY GRADIENT ON THE EFFICIENCY OF WATER FLOCCULATION International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 5, May 2018, pp. 969 977, Article ID: IJCIET_09_05_107 Available online at http://www.iaeme.com/ijciet/issues.asp?jtype=ijciet&vtype=9&itype=5

More information

3.5.7 Flow Through Simple Dies

3.5.7 Flow Through Simple Dies 152 3 Fundamentals of Polymers isothermal spinning of a Newtonian fluid and predicted the critical draw ratio of 20.210. Below the critical draw ratio, any disturbance along the filament is dampened out

More information

Power Consumption in Mixing and Aerating of Shear Thinning Fluid in a Stirred Vessel

Power Consumption in Mixing and Aerating of Shear Thinning Fluid in a Stirred Vessel A. BOMBAÈ et al., Power Consumption in Mixing and Aerating of Shear Thinning, Chem. Biochem. Eng. Q. 21 (2) 131 138 (2007) 131 Power Consumption in Mixing and Aerating of Shear Thinning Fluid in a Stirred

More information

New Developments in BioWin 5.3

New Developments in BioWin 5.3 New Developments in BioWin 5.3 December 6, 2017 BioWin 5.3 contains a new Granular Sludge Sequencing Tank element to model this process, which is gaining acceptance worldwide as an effective wastewater

More information

A Numerical Investigation on bubble formation in Coolant channel with various Ethylene Glycol and water compositions and change in contact angle

A Numerical Investigation on bubble formation in Coolant channel with various Ethylene Glycol and water compositions and change in contact angle 2016 IEEE 23rd International Conference on High Performance Computing Workshops A Numerical Investigation on bubble formation in Coolant channel with various Ethylene Glycol and water compositions and

More information

CTB3365x Introduction to Water Treatment

CTB3365x Introduction to Water Treatment CTB3365x Introduction to Water Treatment W2c Primary sedimentation Jules van Lier The screened and de-gritted sewage is further conveyed towards the biological treatment step. Can we remove some part of

More information

Large scale backfill technology and equipment

Large scale backfill technology and equipment Mine Fill 2014 Y Potvin and AG Grice (eds) 2014 Australian Centre for Geomechanics, Perth, ISBN 978-0-9870937-8-3 https://papers.acg.uwa.edu.au/p/1404_04_zhang/ P Zhang China ENFI Engineering Corp., China

More information

ME 239: Rocket Propulsion. Real Nozzles. J. M. Meyers, PhD

ME 239: Rocket Propulsion. Real Nozzles. J. M. Meyers, PhD ME 239: Rocket Propulsion Real Nozzles J. M. Meyers, PhD 1 Most Typical Real Nozzle Effects 1) Divergence of the flow 2) Low nozzle contraction ratios ( / ) 3) Boundary Layer Flow 4) Multiphase Flow 5)

More information

Sustainable agitator and reactor design for demanding applications in hydrometallurgy

Sustainable agitator and reactor design for demanding applications in hydrometallurgy Sustainable agitator and reactor design for demanding applications in hydrometallurgy Marko Latva-Kokko, Tuomas Hirsi and Teemu Ritasalo Outotec, Finland ABSTRACT Reactor design plays a very important

More information

Trouble-shooting Fermentation and Primary recovery manufacturing issues in order to optimize antigen expression for the Vaccine business

Trouble-shooting Fermentation and Primary recovery manufacturing issues in order to optimize antigen expression for the Vaccine business Trouble-shooting Fermentation and Primary recovery manufacturing issues in order to optimize antigen expression for the Vaccine business Tim Lee, Ph.D. 1 Agenda Fermentation manufacturing issues in antigen

More information

Stirrer design optimization for improving efficiency of a lead refinery

Stirrer design optimization for improving efficiency of a lead refinery Computational fluid dynamics in metallurgy Stirrer design optimization for improving efficiency of a lead refinery Summary Lead refinery processes typically occur in heated kettles, in which stirrers ensure

More information

New Brunswick fermentors and bioreactors for research through production

New Brunswick fermentors and bioreactors for research through production Culture success New Brunswick fermentors and bioreactors for research through production New Brunswick fermentors & bioreactors for all your culture needs New Brunswick fermentors and bioreactors by Eppendorf

More information

2008 International ANSYS Conference

2008 International ANSYS Conference 2008 International ANSYS Conference Computational Modeling of Industrial Biofuel Reactors Jaydeep Kulkarni Presenter: Genong Li Technical Account Manager ANSYS, Inc. 2008 ANSYS, Inc. All rights reserved.

More information

SCHOOL OF COMPUTING, ENGINEERING AND MATHEMATICS SEMESTER 1 EXAMINATIONS 2015/2016 ME257. Fluid Dynamics

SCHOOL OF COMPUTING, ENGINEERING AND MATHEMATICS SEMESTER 1 EXAMINATIONS 2015/2016 ME257. Fluid Dynamics s SCHOOL OF COMPUTING, ENGINEERING AND MATHEMATICS SEMESTER 1 EXAMINATIONS 2015/2016 ME257 Fluid Dynamics Time allowed: TWO hours Answer: Answer TWO from THREE questions in section A and TWO from THREE

More information

Physical Simulation of a CZ-Process of Semiconductor Single Crystal Growth

Physical Simulation of a CZ-Process of Semiconductor Single Crystal Growth International Scientific Colloquium Modeling for Saving Resources Riga, May 17-18, 2001 Physical Simulation of a CZ-Process of Semiconductor Single Crystal Growth L. Gorbunov, A. Klyukin, A. Pedchenko,

More information

SCALE-DOWN STUDIES FOR ASSESSING THE IMPACT OF DIFFERENT STRESS PARAMETERS ON GROWTH AND PRODUCT QUALITY DURING MAMMALIAN CELL CULTURE

SCALE-DOWN STUDIES FOR ASSESSING THE IMPACT OF DIFFERENT STRESS PARAMETERS ON GROWTH AND PRODUCT QUALITY DURING MAMMALIAN CELL CULTURE 14 th European Conference on Mixing Warszawa, 1-13 September 12 SCALE-DOWN STUDIES FOR ASSESSING THE IMPACT OF DIFFERENT STRESS PARAMETERS ON GROWTH AND PRODUCT QUALITY DURING MAMMALIAN CELL CULTURE William

More information

SCREW DESIGN BASICS The Processor Point Of View. Andrew W. Christie Optex Process Solutions, LLC

SCREW DESIGN BASICS The Processor Point Of View. Andrew W. Christie Optex Process Solutions, LLC SCREW DESIGN BASICS The Processor Point Of View Andrew W. Christie Optex Process Solutions, LLC www.optexprocesssolutions.com Outline Define the goal Review basic extruder components Discuss process elements

More information

MODULE 3 - BEARINGS LECTURE 1- SLIDING CONTACT BEARINGS INTRODUCTION

MODULE 3 - BEARINGS LECTURE 1- SLIDING CONTACT BEARINGS INTRODUCTION MODULE 3 - BEARINGS CONTENTS LECTURE 1- SLIDING CONTACT BEARINGS INTRODUCTION 1. Sliding contact bearings - introduction. 2. Sliding contact bearings - advantages and disadvantages. 3. Classification of

More information

NUMERICAL SIMULATION AND OPTIMIZATION OF SOLID-LIQUID TWO-PHASE FLOW IN A BACK-SWEPT AXIAL FLOW PUMP

NUMERICAL SIMULATION AND OPTIMIZATION OF SOLID-LIQUID TWO-PHASE FLOW IN A BACK-SWEPT AXIAL FLOW PUMP THERMAL SCIENCE, Year 2017, Vol. 21, No. 4, pp. 1751-1757 1751 NUMERICAL SIMULATION AND OPTIMIZATION OF SOLID-LIQUID TWO-PHASE FLOW IN A BACK-SWEPT AXIAL FLOW PUMP by De-Sheng ZHANG *, Qiang PAN, Hu ZHANG,

More information

Available online Research Article. Reactor design strategy: Production of xanthan from sugarcane broth

Available online  Research Article. Reactor design strategy: Production of xanthan from sugarcane broth Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2015, 7(5):323-329 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 Reactor design strategy: Production of xanthan from

More information

Processing emulsions and suspensions. Lecture 8

Processing emulsions and suspensions. Lecture 8 Processing emulsions and suspensions Lecture 8 High Speed Mixers Typical speed are 3,000 to 4,000 RPM, the cavitation limit. Shear rate 3,000 RPM 1 meter circumference 0.5 M from blade to wall -1 = 100

More information

Static Mixers Applications Working Principle Sizing your Static Mixer Overview Production

Static Mixers Applications Working Principle Sizing your Static Mixer Overview Production VERDERMI STATIC static mixers MIERS Static Mixers Applications Working Principle Sizing your Static Mixer Overview Production Verdermix Static Mixers The Verdermix series Static Mixers is a well balanced

More information

Disposable rocking bioreactors for recombinant. protein production in Escherichia coli: Physical. expression

Disposable rocking bioreactors for recombinant. protein production in Escherichia coli: Physical. expression Disposable rocking bioreactors for recombinant protein production in Escherichia coli: Physical characterization and assessment of therapeutic protein expression by Adam Westbrook A thesis presented to

More information

Solid-liquid Mass Transfer in an Agitated Dissolution System with High Slurry Concentration

Solid-liquid Mass Transfer in an Agitated Dissolution System with High Slurry Concentration Solid-liquid Mass Transfer in an Agitated Dissolution System with High Slurry Concentration A thesis submitted for the degree of MASTER OF ENGINEERING by Chongguang (Charles) Yu School of Civil, Environmental

More information

Basic design of laboratory bioreactor

Basic design of laboratory bioreactor Basic design of laboratory bioreactor In terms of the construction, the following variants of the laboratory bioreactor can be made: 1. Glass bioreactor (without a jacket) with an upper stainless steel

More information

version BROCHURE Laboratory Bioreactor / Fermentor

version BROCHURE Laboratory Bioreactor / Fermentor version 1.0 2018 BROCHURE Laboratory Bioreactor / Fermentor Laboratory Winpact Benchtop SIP (FS-05S / FS-07S) Semi-automatic sterilization-in-place for stainless steel vessels Stainless steel vessel compatible

More information

1433/06/28. Reactor Design

1433/06/28. Reactor Design Reactor Design 1 2 1 Algae Microalgae Macroalgae Algae cultivation can be achieved in two ways: Open ponds Photobioreactors (PBR) 3 Open ponds Easier to construct and operate than most closed systems Contamination

More information

BT6502 BIOPROCESS ENGINEERING

BT6502 BIOPROCESS ENGINEERING 1 COURSE OUTCOMES On completion of this course, the students will be able to CO No Course Outcomes C302.1 Select appropriate bioreactor configurations and operation modes based upon the nature of bioproducts

More information

Outline. Introduction Case Studies. Anoxic Zone Mixing Channel Mixing. Theory and Criteria. Mixing Theory Design Criteria.

Outline. Introduction Case Studies. Anoxic Zone Mixing Channel Mixing. Theory and Criteria. Mixing Theory Design Criteria. Outline Introduction Case Studies Anoxic Zone Mixing Channel Mixing Theory and Criteria Mixing Theory Design Criteria Recommendations Where Do We Mix at WWTPs? Introduction Flow Equalization Tanks Headworks

More information

EFFECT OF BAFFLES ON SOLID-LIQUID MASS TRANSFER COEFFICIENT IN HIGH SOLID CONCENTRATION MIXING

EFFECT OF BAFFLES ON SOLID-LIQUID MASS TRANSFER COEFFICIENT IN HIGH SOLID CONCENTRATION MIXING EFFECT OF BAFFLES ON SOLID-LIQUID MASS TRANSFER COEFFICIENT IN HIGH SOLID CONCENTRATION MIXING Eng Ying Bong 1, Rajarathinam Parthasarathy 1 *, Jie Wu 2 and Nicky Eshtiaghi 1 1 School of Civil, Environmental

More information

Bio Reactor Systems. Contact for further information, or call +44 (0)

Bio Reactor Systems. Contact for further information, or call +44 (0) Bio Reactor Systems The bench mark for R+D Bio-reactors Single and parallel fully automated, modular systems Aerobic, anaerobic plus microbial, cell cultures and bio-fuels Range of interchangeable size

More information

The importance of optimising sump design for the reliable operation of rotodynamic pumps

The importance of optimising sump design for the reliable operation of rotodynamic pumps The importance of optimising sump design for the reliable operation of rotodynamic pumps Richard Brewis Project Engineer BHR Group Steve Graham Sales Director Bedford Pumps Ltd 02 Why is it important to

More information

Sanitary and Environmental Engineering I (4 th Year Civil)

Sanitary and Environmental Engineering I (4 th Year Civil) Sanitary and Environmental Engineering I (4 th Year Civil) Prepared by Dr.Khaled Zaher Assistant Professor, Public Works Engineering Department, Faculty of Engineering, Cairo University Wastewater Flow

More information

Convective heat transfer and flow characteristics of Cu-water nanofluid

Convective heat transfer and flow characteristics of Cu-water nanofluid Vol. 45 No. 4 SCIENCE IN CHINA (Series E) August 2002 Convective heat transfer and flow characteristics of Cu-water nanofluid LI Qiang XUAN Yimin School of Power Engineering, Nanjing University of Science

More information

UNIT I FLUID PROPERTIES AND FLUID STATICS

UNIT I FLUID PROPERTIES AND FLUID STATICS SIDDHARTH GROUP OF INSTITUTIONS :: PUTTUR Siddharth Nagar, Narayanavanam Road 517583 QUESTION BANK (DESCRIPTIVE) Subject with Code : FM & HM (16CE112) Year & Sem: II-B.Tech & I-Sem Course & Branch: B.Tech

More information

Twin Screw Extruder and Continuous Mixer Rate Limitations

Twin Screw Extruder and Continuous Mixer Rate Limitations MPC Materials Processing Consultants LLC Twin Screw Extruder and Continuous Mixer Rate Limitations Anthony C. Neubauer SPE Fellow; Dow Fellow (retired) Materials Processing Consultants LLC Why Extruders?

More information