Inline mixer

Motionless inline mixers obtain energy for mixing and dispersion from the pressure drops developed as the phases flow at high velocity through an array of baffles or packing in a tube. Performance data on the Kenics (132) and Sul2er (133) types of motionless mixer have been reported. 

Fig. 16. Two-hquid flotation flow sheet (39). The original ROM is kaolin (white clay) that contains 11% impurity in the form of mica, anatase, and siUca. Treatment produces high purity kaolin and a Ti02-rich fraction. A, Kaolin stockpile D, dispersant (sodium siUcate plus alkah) W, water K, kerosene C, collector (sodium oleate) RK, recycled kerosene S, screen M, inline mixer SPR, separator CFG, centrifuge P, product and T, to waste.

Three basic fluid contacting patterns describe the majority of gas-liquid mixing operations. These are (1) mixed gas/mixed liquid - a stirred tank with continuous in and out gas and liquid flow (2) mixed gas/batch mixed liquid - a stirred tank with continuous in and out gas flow only (3) concurrent plug flow of gas and liquid - an inline mixer with continuous in and out flow. For these cases the material balance/rate expressions and resulting performance equations can be formalized as ... 

For the continuous mixing of low viscosity fluids inline mixers can be used. For other mixing operations stirred vessels or proprietary mixing equipment will be required. 

The static inline mixer shown in Figure 10.53 is effective in both laminar and turbulent flow, and can be used to mix viscous mixtures. The division and rotation of the fluid at each element causes rapid radical mixing see Rosenzweig (1977) and Baker (1991). The... 

Centrifugal pumps are effective inline mixers for blending and dispersing liquids. Various proprietary motor-driven inline mixers are also used for special applications see Perry et al. (1997). 

Motionless mixers (and inline mixers in general) present an alternative to the more traditional agitated vessel. These devices are particularly useful for the continuous processing of chemicals but are also incorporated as part of a batch system in pump-around loops. 

MIXING PERFORMANCE OF INLINE MIXERS 4.1. Macromixing (or Blending) Performance... 

A static inline mixer is essentially a device that provides transverse uniformity and not longitudinal or time-interval blending. Hence, if a particle in Fig. 35 is ever to catch up with another particle behind it, there must be a tank volume such that the first particle can remain until the latter one catches up with it. 

Mechanical inline mixers have a relatively high-speed impeller, rotating in a small volume, usually on the order of gal to perhaps 50 or 60 gal. Obviously, with a big enough tank, you then have a system that really does not fit in the pipe-line itself. Usually, the flow is directed through two stages, the flow comes in the bottom of the container, flows up through a hole in a static plate into a stage divider, and then flows in the second impeller. The power is such that... 

Equipment that is used to make emulsions can, in many cases, be used to break API particles suspended in liquid. Examples include toothed high-shear inline mixers and cone or colloid mills. Important parameters... 

It is clear that by bringing the contents of beakers 1 and 2 together, the concentration of the mixture has changed. Continuous mixing is also possible. Consider a simplified inline mixer obtained by connecting two process streams with a tee piece. One of the lines (line 1) contains a concentration equivalent to that found in beaker 1, whereas the other line is filled with a concentration equal to the concentration in beaker 2. On the other end of the tee, the combined contents from streams 1 and 2 join as stream 3. This arrangement is shown in Figure 2.10. 

An in-line pH control system is installed when the brine is to be acidified. HCl is added upstream of an inline mixer, with measurement downstream of the mixer. This is a simple case of pH control, the end point being fairly low. The process gain is also low in this case, and control is easier than in the first stage of the pH adjustment, described in the previous section. The acid valve should be a fail-closed globe valve of equal percentage characteristic with full PTFE lining and FIFE bellows. An interlock should close the acid feed valve whenever there is no brine flow or no current on the cells. 

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