Static mixers costs

Static mixers are typically less effective in turbulent flow than an open tube when the comparison is made on the basis of constant pressure drop or capital cost. Whether laminar or turbulent, design correlations are generally lacking or else are vendor-proprietary and are rarely been subject to peer review. 

Cost for reactor 50,000 (50-gal reactor) and of reactants and products is critical reverse quenches tight temperature controls efficient mixing of heterogeneous streams localization of catalysts and physical effects Under 1000 for static mixer for pilot... 

It is possible to improve the mixing performance of single-screw machines by the use of additional mixing heads or by the use of in-line static mixers described earlier. Several such devices are available commercially and mixing will be improved in comparison with the single screw alone. However, additional capital cost and power requirement will be incurred. Figure 7.18... 

The static mixer can reduce the contact time required for any particular process at the cost of increased energy consumption. In some cases, e.g. heat transfer, the increase in energy requirements is very large but, equally, mixing energy is not a large cost for many of these processes in the context of overall plant energy requirements. 

The static mixer has particular advantages it is particularly suited to continuous operation it is potentially of small size it has no moving parts there is considerable freedom in the choice of materials of construction. For these reasons alone there must be many operations where a static mixer is the best choice. However, at the moment, the only way a buyer can judge what is the best choice for his process is to balance the cost of the quotation and the reputation of the manufacturer. 

Static mixers consistency, high quality and cost savings for extmded parts, industry web fact sheet (www.omnexus.com). SpecialChem-Omnexus 2008 (downloaded 10 July 2008). 

Static mixers Easy to operate Satisfactory performance at lower cost Performance completely dependent on packing/internals Good performance only in a limited range of flow rates... 

Kenics-type static mixers have been used as inserts in tubular reactors. Compared to an open tube operated at the same pressure drop, the static mixer gives about 40% more heat transfer. Stand-alone mixer reactors of the Koch or Sultzer SMR type have been used as post-reactors and devolatilization preheaters. The polymer flows through the shell side of the SMR and the heat transfer fluid flows inside tubes that have been strategically placed to promote radial mixing of the polymer. One bulk polystyrene process used the SMR as in a recycle loop as the first reactor, but the capital cost is high compared to alternatives such as a boiling CSTR or a proprietary stirred-tube reactor. 

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