High flow rate for

Mutton, I. M. Use of short columns and high flow rates for rapid gradient reversed-phase chromatography. Chromatographia 1998, 47, 291-298. 

To overcome thermal entry effects, the segments may be virtually stacked with the outlet conditions from one segment that becomes the inlet conditions for the next downstream section. In this approach, axial conduction cannot be included, as there is no mechanism for energy to transport from a downstream section back to an upstream section. Thus, this method is limited to reasonably high flow rates for which axial conduction is negligible compared to the convective flow of enthalpy. At the industrial flow rates simulated, it is a common practice to neglect axial conduction entirely. The objective, however, is not to simulate a longer section of bed, but to provide a developed inlet temperature profile to the test section. 

Reproducibility of monolithic columns has also been cited as a major concern because the monoliths are manufactured individually.34-35 An extensive study by Kele and Guiochon indicates that the reproducibility results of Chromolith columns were almost comparable to those from different batches of particle-packed columns.37 Other drawbacks of monolithic columns include weak reten-tivity for polar analytes,38 efficiency loss at high flow rates for larger (800 MW) molecules,39 and peak tailing, even for neutral non-ionizable compounds.36-38-40 Furthermore, silica-based monolithic... 

Overall, the most effective factor in Equation 5.20 is the particle size. The smaller the particle size, the higher the column efficiency. Equations 5.13, 5.15, and 5.18 are depicted in Figure 5.6 against flow velocity as A, B, and C, respectively. The band spreading is thus influenced by Equation 5.15 at a low flow rate. The band spreading is influenced by Equations 5.18 and 5.19 at a high flow rate. For gas chromatography curve D is obtained. 

The present method recommended by this major industrial account is to disconnect the center-voided column, grasp it in one hand, and rap the counter with it twice, reverse the column, and do the same with the other end. Obviously, not hard enough to bend the column Hook it up backwards and run it at high flow rate for a minute or two. Then run the four-standard mixture. The column is run reversed from then on. It is possible that an end void may be formed yielding rabbit-eared split peaks, and must be repacked, but the column bed should be restored. 

CSTR for most reactions. These conditions are best met for short residence times where velocity profiles in the tubes can be maintained in the turbulent flow regime. In an empty tube this requires high flow rates for packed columns the flow rates need not be as high. Noncatalytic reactions performed in PFRs include high-pressure polymerization of ethylene and naphtha conversion to ethylene. A gas-liquid noncatalytic PFR is used for adipinic nitrile production. A gas-solid PFR is a packed-bed reactor (Section IV). An example of a noncatalytic gas-solid PFR is the convertor for steel production. Catalytic PFRs are used for sulfur dioxide combustion and ammonia synthesis. 

Monolithic reactors, similar to many other structured reactors, offer high precision combined with a high efficiency. They are a valuable tool for process intensification. Most practical applications of these reactors are found in environmental catalysis, motivated by the ambition to realize low-pressure drops at high flow rates for gas-phase reactants. Monoliths are the state-of-the-art reactors in these applications. 

The effect of a very high flow rate for the investigation of a polydisperse mfarture is illustrated in Fig. 15, where J = 15 mL s was selected for the above flow experiment. In this case the concentration of the Cs ions in the effluent solution is nearly the same as that in the influent and... 

Mutton, I.M. Use of Short Columns and High Flow Rates for Rapid Gradient Reversed-Phase Chromatography, Chromatographia 47,291-298 (1998). 

C. Safety Systems. The cell room hydrogen header should be automatically purged with nitrogen at high flow rate for a fixed time whenever the rectifiers shut down (Fig. 11.40). This ensures that condensation of water vapor does not lower the header... 

Moreover, reattachment of the segments probably beeomes more difficult for large moleeules. The effect of shear rate nicely illustrates that a polymer can adsorb with high affinity, even if the interaction energy of a single segment with the surface is relatively low. In Fig. 16 the effect of molar mass on the rate of detachment is shown for the ease of high flow rate. For the lowest molar mass, eomplete desorption occurs after about 2 h. For low flow rates (not shown) the polymer is only partially desorbed. 

Although perfectly usable on the scale, and in the sizes of, liquid bag filters, the corresponding units for gas filtration are usually much larger, and are used in the multiple element installations, because they usually have to deal with very high flow rates. For the small-scale treatment of gas streams, the pad and panel filters of Section 3J are most commonly employed. 

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