Static capital cost

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. 

Static extraction columns Spray column Baffle column Packed column (random and structured packing) Sieve tray column Deliver low to medium mass-transfer efficiency, simple construction (no internal moving parts), low capital cost, low operating and maintenance costs, best suited to systems with low to moderate interfacial tension, can handle high production rates Petrochemical Chemical Food... 

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... 

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. 

While fabric filters have relatively low capital coats, their operating costs are high. Well maintained fabric filters can reliably reduce dust concentrations to below 50mg/Nm. Where incompletely combusted fuels are likely to be present the bags should be earthed, to prevent build-up of static electricity, and the filter housing should incorporate a suitably designed explosion vent. 

The installation of a Norelco recondensing system was estimated at 65, 000 with approximately 4,000 calculated as the annual cost of operating the recovery system. Based on annual fixed charges of 28 per cent of capital investment, the net profit to the storage facility is calculated at 37, 000 annually on an incremental investment of 20,000, Thus, in special applications where the static heat leak to the tank is not the only loss factor, the combined use of a tank with less effective insulation and a vapor recovery system could effect large savings for the installation. 

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