Paraffins liquid-phase extraction

The liquid-phase extraction process operates at 177°C and 24.6 kg/cm (g), whereas the vapor-phase extraction process operates at 310-350°C and 2.2 kg/cm (a). Most importantly, the n-paraffin product from either process can surpass 99% purity and attain paraffin recoveries exceeding 95%. 

The role of a second liquid phase in photochemical sulphoxidation of paraffins with SO2 and O2 mixtures may also be cited, where water is used to extract sulphonic acid to prevent formation of di- and poly-sulphonic acids (Fischer, 1978). 

Since the Sorbex process is a liquid-phase fixed-bed process, the selection of particle size is an important consideration for pressure drop and process hydraulics. The exact particle size is optimized for each particular Molex process to balance the liquid phase diffusion rates and adsorbent bed frictional pressure drop. The Sorbex process consists of a finite number of interconnected adsorbent beds. These beds are allocated between the following four Sorbex zones zone 1 is identified as the adsorption zone, zone 2 is identified as the purification zone, zone 3 is identified as the desorption and zone 4 is identified as the buffer zone. The total number of beds and their allocation between the different Sorbex zones is dependent on the desired performance of the particular Molex process. Molex process performance is defined by two parameters extract normal paraffin purity and degree of normal paraffin recovery from the corresponding feedstock. Details about the zone and the bed allocations for each Molex process are covered in subsequent discussions about each process. 

Dissociation of tren NaBr. Solid tren NaBr (12.5 grams) was loaded in an Alundum extraction thimble which was then placed in a Soxhlet extractor. After extraction with 250 ml Isopar G (Enjay iso-paraffinic solvent, bp 159°-177°C) for 2-8 hours, the solution was cooled to room temperature a phase separation resulted. The lower liquid phase (containing pure tren and 1-3 wt % Isopar G) was removed. Solvent recycle gave quantitative recoveries of NaBr and polyamine. 

In both the liquid- and vapor-phase extraction processes, the kerosene feed is typically prefractionated to narrow the feed to the desired four-carbon number range (either Cjo-Cu or C11-C14). This heartcut is hydrotreated to remove the majority of kerosene contaminants that may compromise the performance of life of the adsorbent or subsequent quality of the LAB or LAS properties. In some process flow schemes, the fractionation into the discrete n-paraffin cuts may be deferred until after the extraction process. 

The linear paraffins used for LAB production are obtained by liquid- or vapor-phase extraction from kerosene followed by fractionation to obtain the C10-C13 cut or narrower C-chain... 

Fan et al. (312) report the alkylation on Y-type zeolite catalysts of two olefin/paraffin systems (a) isobutene with isopentane and (b) isobutene with isobutane. The isopentane and isobutane, respectively, were also used as the solvents in this work, and results were compared for gas-, liquid-, and SCF-phase conditions. Alkylations conducted in the SCF phase were reported to exhibit higher activity and longer catalyst lifetimes in comparison with reactions conducted in the gas and liquid phases. Catalyst deactivation observed in the gas-and liquid-phase results was attributed to deposition of high-molecular-weight olefinic oligomers on the Lewis acidic sites that were determined to be active for the alkylation reactions. Operation under SCF-phase conditions resulted in successful extraction of these oligomers in situ and extended the catalyst life. Additional aspects of this report are discussed in a subsequent commentary (313) and rebuttal (314). 

Because of the negative enthalpy of reaction the liquid is recirculated. In a 95-m3 separator (2) the upper paraffin phase is removed from the extract phase,... 

Description Hydrocarbon feed is pumped to the liquid-liquid extraction column (1) where the aromatics are dissolved selectively in the sulfolane water-based solvent and separated from the insoluble non-aromatics (paraffins, olefins and naphthenes). The non-aromatic raffinate phase exits at the top of the column and is sent to the wash tower (2). The wash tower recovers dissolved and entrained sulfolane by water extraction and the raffinate is sent to storage. Water containing sulfolane is sent to the water stripper. 

Solvent extraction Solvent extraction is a method of separating compounds based on their solubility in different immiscible liquids. In industrial processes, solvents are typically transferred from an aqueous phase to an organic phase. Viscosity index Viscosity index is a measure of the change of kinematic viscosity with temperature and indicates an oil s ability to lubricate with a change in temperature. The VI scale set by the Society of Automotive Engineers (SAE) is 0 (worst) to 100 (best). VI = 0 is naphthenic oil and VI = 100 is paraffinic oil. 

For separations not now possible by other methods In distillation, where the vapor phase is created from the liquid by addition of heat, the vapor and liquid are necessarily composed of the same substances and are therefore chemically very similar. The separations produced then depend upon the vapor pressures of the substances. In liquid extraction, in contrast, the major constituents of the two phases are chemically very different, and this makes separations according to chemical type possible. For example, aromatic and paraffinic hydrocarbons... 

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