Regeneration frequency

At times, the process stream flow must be increased after the initial installation to satisfy production demands. Depending on the magnitude of the increase, the existing system may or may not be able to handle the added flow. If it can, regeneration frequency must increase. Adding more resin to the column is often considered an alternative to installing another column. Resin addition lessens the space for backwash and may be a cause for poor column performance. 

The design frequency of regeneration is normally from three to six months for semi-regenerative units, and one reactor every 24 hours in cyclic units. For either case, an increase in regeneration frequency would result in a reduction in average catalyst coke level. Thus, gasoline yields would increase and catalyst requirements decrease. 

The feed is vaporized by reactor effluent heat-exchange and enters into the dehydration reactor. The dehydration reactor effluent is mixed with preheated recycle gas and enters the conversion reactors. Although Figure 10 shows four parallel or "swing conversion reactors, a lesser or greater number of reactors may be used depending upon the feed rate and regeneration frequency desired. 

Fig. 10. Effect of agitation speed on cell concentration (A) and regeneration frequency (B) of rice calli in TBR without (o, ) and with (a, ) supports. Dotted lines show the results of the control culture...

Isolate Collection origin and year Explants CaUus induction frequency (%) Plant regeneration frequency (%) Reference... 

Table 2. Summary of callus induction and plant regeneration frequencies in tissue culture systems using different genotypes. — means undefined or unverified in the relevant reference, w means wild-type plants in its collection origin...

Liu, G.S. Li, X.F. Su, M. Qi, D.M. (2006). A protocol for enhancing plant regeneration frequency of Leymus chinensis and the appropriatioe tissue culture media. State... 

Point-of-use (POU) filters have been developed as well (Gurian et ah, 2002). The replacement or regeneration frequency of the adsorbents can be nhnirnized if the filtrate is only used for drinking water purposes (Petrusevski et ah, 2002). However, the synthesis of most adsorbents, especially efficient adsorbents, are complex, and their performance of re-use is poor, and this process will produce large amounts ofAs sludge or As containing solid wastes, and other treatment methods are still much desired. 

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