Loss of Fines

Loss of fine solids from the bed reduces the quality of fluidization and reduces the area of contact between the solids and the gas in the process. In a catalytic process this means lower conversion. 

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One practical aspect of the procedure for monitoring carbon flow following C labeling is the need to separate roots from the soil for analysis. Incomplete removal of roots can lead to an overestimation of rhizodeposition, but overzealous washing of soil may lead to leaching of " C or loss of fine roots. This problem has been examined in detail for wheat and barley, and procedures to correct for these errors have been developed (69). 

MIP are often generated as simple bulk polymers to be ground into fine particles, which are subsequently sieved and sedimented - admittedly a time-consuming process, which requires large amounts of solvents. The loss of fine polymer particles in the sedimentation procedure is also not negligible. The result usually is a polymer powder with particle sizes of a relative broad size distribution. After the template has been extracted, this material can be packed into LC-columns [17,29,30], CE-capillaries, or be used directly in the batch mode. 

The oil has to be removed from the SSP product by extraction or flushing with appropriate solvents such as acetone. The degree of swelling influences abrasion and the loss of fines, as well as a certain tendency to a form of sticking or adhesion. At present, this method does not appear to have been fully commercialized. 

A substituent at C(l) of hexahelicene 22) and heptahelicene 20) results in a batho-chromic shift of the a- and p-band and a loss of fine structure. A bridge over the terminal rings of heptahelicene (57) has the same effect. The spectra of the double helicenes are more structured than the carbohelicenes with the same number of benzene rings (see Fig. 6,). 

The effect of water cosolvent on the emission of 2-naphthol is shown in Figure 2. There is some loss of fine structure but no detectable peak in the 400-500 nm range indicative of the anion species. This lack of anion emission is likely due to the low concentration of water in the solution, and since the concentration is limited by the water/CC>2 phase equilibria (18), there is a need for a more sensitive probe. 

The effect of water (0.003 mole fraction) and methanol (0.02 mole fraction) cosolvents on the emission of 5CN2N is shown in Figure 4. For this probe there is complete loss of fine structure, a significant red shift in the neutral emission with methanol cosolvent, but again, no detectable anion emission. 

Deactivation of catalysts for hydrocarbon reactions can thus involve the loss of active sites by poisoning (by P or V or carbonaceous species), sintering, attrition (with loss of fines) or fouling. 

Then attrition and loss of fines will simply reduce all S values proportionately, while fouling will reduce diffusion coefficients to and from the available sites [3]. However, the formation of carbonaceous deposits can reduce the total number of sites available for reaction at zero time S-r= + S4l + Sa + Sh at time t ST= v + S, + + h + Sc... 

The steam distillation residue contains heavy oils and asphaltenes. These were separated by solubility differentiation. Both of these materials were sufficiently soluble in CCl, to permit examination by both IR and NMR. Principal featuris of the IR and NMR spectra are shown in Table VI. The possibility of colloidal dispersion of the asphaltenes instead of true solubility may have caused some loss of fine structure for the aromatic absorption regions. 

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