Ease of separation

Selectivity is a relative term that means a desorbent must have balanced strength or selectivity for the adsorbent relative to the desired feed normal paraffins. A desorbent that is more strongly held by the adsorbent than the feed normal paraffins will be difficult for the desired feed normal paraffins to displace from the adsorbent This results in poor adsorbent utihzation due to a loss in selective volume. At the same time, a desorbent carmot be too weakly attracted to the selective volume (relative to the feed normal paraffins) or excessive desorbent circulation is needed to displace the feed component from the adsorbent. In this situation, excessively high desorbent rates are needed to recover feed normal paraffins from the adsorbent These high desorbent flush rates result in non-economical process conditions due to excessively high utility consumption in post-Sorbex product fractionation. 

The second desorbent characteristic is that the desorbent material must be compatible with both the particular adsorbent and the feed mixture. Specifically, the desorbent must not reduce the capacity of the adsorbent or normal paraffin selectivity with respect to the raffinate components. Additionally, desorbent materials must not react with any feed component Both the extract stream and the raffinate streams consist of a mixture of feed components with desorbent and any chemical reaction prevent product recovery. 

The third desorbent characteristic is that the desorbent material must be easily separated from the two Sorbex process products extract and raffinate. The adsorbent chamber s composition profile produces extract and raffinate streams comin-gled with desorbent. In order for the process to be economical, the separation of the feed components from the desorbent (achieved through fractionation) is set by the boiling point differences between the species. Depending on the selectivity possessed by the desorbent over that of the feed normals, the subsequent desorbent rates needed to flush feed normal paraffins from the adsorbent s selective volume and the resulting extract or raffinate streams from the Sorbex chambers could contain in some cases more than 50% desorbent. High concentration of desorbent demonstrates the importance of the desorbent characteristics when selecting a desorbent. 

The fourth desorbent characteristic is that the desorbent material should be readily available (at a sustainable cost). It is important that the desorbent be readily available and not cost-prohibitive because desorbent is gradually lost during operations. Since the desorbent is separated from both the extract and raffinate components by fractionation, trace quantities (parts per million) of desorbent are present in the respective product streams due to fractionation tray efficiencies and fractionation control optimization of reflux to feed ratio. Ultimately, each n-paraffn separation facility must balance the operating expenses (utilities consumed during fractionation) to minimize desorbent loss against the replacement value of desorbent to maintain inventory. 

The fifth and final desorbent characteristic is that the desorbent must not react with any feed components that would impart any negative characteristics on either the final extract and raffinate streams. This is important not only for the desired paraffin product purity but also for retaining the desorbent inventory. Therefore, a desorbent s reactivity must be quantified early in the desorbent selection process. 

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If inert material is to be added, then ease of separation is an important consideration. For example, steam is added as an inert to hydrocarbon cracking reactions and is an attractive material in this respect because it is easily separated from the hydrocarbon components by condensation. If the reaction does not involve any change in the number of moles, inert material has no effect on equilibrium conversion. 

Increased agitation of a given acid—hydrocarbon dispersion results in an increase in interfacial areas owing to a decrease in the average diameter of the dispersed droplets. In addition, the diameters of the droplets also decrease to relatively low and nearly constant values as the volume % acid in the dispersions approaches either 0 or 100%. As the droplets decrease in si2e, the ease of separation of the two phases, following completion of nitration, also decreases. 

Liquefied petroleum gases precipitate asphaltic and resinous materials from cmde residues while the lubricating oil constituents remain in solution. Although all Hquefied gases possess this property to some extent, propane and butane are used to deasphalt residual lubricating oils because of their relative low cost and their ease of separation from lubricating oils. 

The relative volatility, a, is a direct measure of the ease of separation by distillation. If a = 1, then component separation is impossible, because the hquid-and vapor-phase compositions are identical. Separation by distillation becomes easier as the value of the relative volatihty becomes increasingly greater than unity. Distillation separations having a values less than 1.2 ate relatively difficult those which have values above 2 are relatively easy. 

Separation by distillation is dependent on the fact that when a Hquid is partially vaporized the vapor and Hquid compositions differ. The vapor phase becomes enriched ia the more volatile components and depleted ia the less volatile components with respect to its equiUbrium Hquid phase. By segregating the phases and repeating the partial vaporization, it is often possible to achieve the desired degree of separation. One measure of the degree of enrichment or the ease of separation is the relative volatiHty defined as ... 

The recovery of cyclopentadiene is based on the rapid dimerization rate of this compound to dicyclopentadiene, and the ease of separating heavy dimer from the feedstock. 

The difference in pH 1/2 values of two metal ions in a specific system is a measure of the ease of separation of the two ions. If the pH1/2 values are sufficiently far... 

Both trans-l amino-2,3-diphenylaziridine and l-amino-2-phenylazi-ridine give a,/S-epoxyhydrazones that fragment in the desired manner between 100° and 200°, the choice of reagent being dictated by the ease of separation of the alkynone from the by-products, (F/)-stilbene and styrene, respectively. The diphenylaziridine is especially useful when the alkynone is relatively volatile and easily separable by distillation from (E)-stilbene, as is the case in the present example. The phenylaziridine... 

Physical form and properties are directly linked to and impact other aspects of a process that is, reactor type, type of mixing, throughput that is, how quickly a chemical will dissolve in a solvent or precipitate out, the ease of separation of two liquids, and so on. 

The amoimt of lipid applied to the plate varies depending on the ease of separation of individual lipid components in the sample. Usually 25 to 50 mg of the neutral lipid sample can be applied to a 20 X 20 cm preparative plate with the silica gel G layer thickness of 0.5 mm, whereas only about 4 mg of phospholipids can be applied on these plates. 

All separations are based on a difference in some property. The separation of the compounds given in Table 4-1 is done by distillation. It is based on the fact that compounds with different vapor pressures will have different compositions in the vapor and liquid phases. The magnitude of this difference, and hence the ease of separation, is directly related to the difference in the vapor pressures. This can be determined from the boiling-point differences. Among the six groups of compounds... 

Considering the characteristics of polymeric materials as supports for catalysts and/or reagents, the key factors that have made their application increasingly popular are ease of separation after the reaction, recyclability, and the possibility of reinstating the catalytic activity post-reaction. 

Ease of separation of tritiated products from a reaction medium is an important feature in the choice of labeling procedure. Sometime ago we used polymer-sup-ported acid and base catalysts [12, 13] to good effect and with the current interest in Green Chemistry one can expect to see more studies where the rate accelerations observed under microwave-enhanced conditions are combined with the use of solid catalysts such as Nafion, or zeolites. 

Despite this selectivity advantage of homogeneous catalysts, almost all of the industrial catalytic processes use heterogeneous catalysts, because of their one major advantage, their ease of separation form the reaction product. Being insoluble in the reaction... 

One of the most studied technologies is supercritical fluid extraction with SC-CO2. The advantages of SC-CO2 include its low processing temperature, which minimizes thermal degradation the ease of separation with no solvent residue left in the final product and minimization of undesirable oxidation reactions. 

Immobilized enzymes are attached to a solid support by adsorption or chemical binding or mechanical entrapment in the pores of a gel structure but retain their catalytic power. Their merit is ease of separation from the finished reaction product. 

Using a fluidized bed electrode, this process was studied by Jircny 1985 [118]. Jircny [119] worked with a laboratory scale cell and subsequently a pilot plant. The pilot plant was designed to produce one ton of D-arabinose per year. The electrochemical reactor was 0.3 x 0.6 x 0.6 m and contained five 225 A cells in series. A major advantage of the electrooxidation over the usual chemical route (oxidation with sodium perchlorate) was the ease of separation of D-arabinose from the reactor outflow. In chemical routes, the separation is made difficult by the presence of large amounts of sodium chloride. 

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