Fractionation Processes

A complete fractionation process to obtain a purified raffinate product and a concentrated extract product may be obtained by coupling together a 

FIGURE 12.5. McCabe-Thiele diagram for complete fractionation process made up of stripping and enrichment sections. (From ref. 1, reprinted with permission of Martinus Nijhoff Publishers.) 

As in distillation, a given separation with defined feed, top, and bottom products may be achieved in different ways a reduction in the number of theoretical stages may be compensated for by increased reflux and vice versa. In any section of the column there is, however, a minimum reflux, defined by Eq. (12.23), below which the required separation cannot be achieved. At this minimum reflux condition, an infinite number of stages would be required. This condition corresponds to the intersection or tangency of equilibrium and 

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Plasma fractionation is unusual in pharmaceutical manufacturing because it involves the processing of proteins and the preparation of multiple products from a single feedstock. A wide range of unit operations are utilized to accompHsh these tasks. They are Hsted in Table 3 some are common to a number of products and all must be closely integrated. The overall manufacturing operation can be represented as a set of individual product streams, each based on the processing of an intermediate product derived from a mainstream fractionation process (Fig. 1). 

Precipitation was the principal protein separation technology initially chosen for the development of an industrially suitable fractionation process. Ethanol [64-17-5] (qv) was selected as the precipitation reagent because of its volatility. It can be subsequently removed using available drying technology... 

The lanthanides readily form double salts, eg, Lri2(SO NajS04 2H2O Lu2(SO MgSO 24H20, which were used historically in the fractionation process. 

Purification Processes. Separation of neutral and polar Hpids, so-called deoiling, is the most important fractionation process in lecithin technology (Fig. 3). Lecithin is fluidized by adding 15—30% acetone under intensive agitation with acetone (fluidized lecithin acetone, 1 5) at 5°C. The mixture goes to a separator where it is agitated for 30 minutes. The agitator is then stopped and the lecithin separates. The oil micella is removed and the acetone evaporated. After condensation the acetone is returned into the process. 

Propane Asphalt. As noted above, cmde oils contain different quantities of residuum (Fig. 2) and, hence, asphalt. Asphalt is also a product of the propane deasphalting and fractionation process (5,6,21,22) which involves the precipitation of asphalt from a residuum stock by treatment with propane under controlled conditions. The petroleum charge stock is usually atmospheric-reduced residue from a primary distillation tower. 

Fig. 3. Schematic representation of propane deasphalting and fractionation process.

The feed to a liquid-liquid extraction process is the solution that contains the components to be separated. The major liquid component in the feed can be referred to as the feed solvent. Minor components in solution are often referred to as solutes. The extraction solvent, or just plain solvent, is the immiscible liquid added to a process for the purpose of extracting a solute or solutes from the feed. The extraction-solvent phase leaving a liquid-liquid contactor is called the extract. The raffinate is the liquid phase left from the feed after being contacted by the second phase. A wash solvent is a hquid added to a liquid-liquid fractionation process to wash or enrich the purity of a solute in the extract phase. 

Product separation for main fractionators is also often called black oil separation. Main fractionators are typically used for such operations as preflash separation, atmospheric crude, gas oil crude, vacuum preflash crude, vacuum crude, visbreaking, coking, and fluid catalytic cracking. In all these services the object is to recover clean, boiling range components from a black multicomponent mixture. But main fractionators are also used in hydrocracker downstream processing. This operation has a clean feed. Nevertheless, whenever you hear the term black oil, understand that what is really meant is main fractionator processing. 

It is basically a fractionation process that depends not only on molecular size, but also on chemical composition, stereo-configuration, branching, and crosslinking. For multicomponent systems, fractionation with different ion polymolecularity, chemical heterogeneity and sequence length distribution, solubility or elution fractionation is of primary importance. Therefore, gel permeation chromatography or size exclusion chromatography is used as an important tool for the characterization of PBAs. 

The most abundant isotope is which constitutes almost 99% of the carbon in nature. About 1% of the carbon atoms are There are, however, small but significant differences in the relative abundance of the carbon isotopes in different carbon reservoirs. The differences in isotopic composition have proven to be an important tool when estimating exchange rates between the reservoirs. Isotopic variations are caused by fractionation processes (discussed below) and, for C, radioactive decay. Formation of takes place only in the upper atmosphere where neutrons generated by cosmic radiation react with nitrogen ... 

Two possibilities for the observed enriched values for many of the grazers, and the often concomitant but slight enrichment of browsers (Fig. 5.6), present themselves. Either these shifts represent atmospheric CO2 enrichment shifts at particular periods during the last -lOOKa represented (the Late Pleistocene), or a hitherto unknown or unrecognized fractionation process has taken place during burial and fossilization. The former hypothesis could be tested by comparison of observations from a larger sample set from the site, with CO2 concentration and carbon isotope data from Antarctic ice-core records or high resolution marine isotope records. 

Thermal polymerization, in which polymerization of cracked gases is implemented at specified temperature and pressure the product is a mixture of gasoline and gas oil. A subsequent fractionation process accomplishes separation between the two. 

MRI has been used as a non-invasive quantitative visualization technique to investigate a class of complex Taylor-Couette-Poiseuille (TCP) flows, which constitute a prototype of many mixing or fractionation processes. Here we focused on the vicinity of the Stationary Helical Vortex (SHV) regime characterized by a... 

Edmister, W. C. (1947) Hydrocarbon absorption and fractionation process design methods, a series of articles published in the Petroleum Engineer from May 1947 to March 1949 (19 parts). Reproduced in A Sourcebook of Technical Literature on Distillation (Gulf). 

In order to overcome these problems, the flow schemes as shown in Figures 1 and 2 were developed. These incorporate the use of Kerr-McGee Corporation s Critical Solvent Deashing and Fractionation Process (CSD) for recovery of the SRC. The Kerr-McGee Process adds extra flexibility since this process can recover heavy solvent for recycle, which is not recoverable by vacuum distillation. EPRI contracted with Conoco Coal Development Company (CCDC) and Kerr-McGee Corporation in 1977-1978 to test these process concepts on continuous bench-scale units. A complementary effort would be made at the Wilsonville Pilot Plant under joint sponsorship by EPRI, DOE, and Kerr-McGee Corporation. This paper presents some of the initial findings. 

Paralleling the work at CCDC were the critical solvent deashing and fractionation studies done on a continuous bench-scale unit at Kerr-McGee Technical Center, Oklahoma City, Oklahoma, Figure 3. The Kerr-McGee Critical Solvent Deashing and Fractionation Process has been previously discussed (3). 

Sulfoxidation and sulfochlorination of of hydrocarbons for the production of detergents. Starting from kerosene fractions, processing rates in the United States and the former U.S.S.R. reached several thousand tons per year. 

Rieley, G. (1994) Derivatization of organic compounds prior to gas chromatographic combustion isotope ratio mass spectrometric analysis identification of isotope fractionation processes. Analyst 119, 915 919. 

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