Aromatic feed

A schematic of the MGCC process is shown in Figure 9. The mixed Cg aromatic feed is sent to an extractor (unit A) where it is in contact with HF—BF and hexane. The MX—HF—BF complex is sent to the decomposer (unit B) or the isomerization section (unit D). In the decomposer, BF is stripped and taken overhead from a condensor—separator (unit C), whereas HF in hexane is recycled from the bottom of C. Recovered MX is sent to column E for further purification. The remaining Cg aromatic compounds and hexane are sent to raffinate column E where residual BE and HE are separated, as well as hexane for recycle. Higher boiling materials are rejected in column H, and EB and OX are recovered in columns I and J. The overhead from J is fed to unit K for PX separation. The raffinate or mother Hquor is then recycled for isomerization. 

Srivastava [434,435], The process can be carried out under aerobic (KSARC56) or anaerobic conditions (Mic-1). The identified products include methane, lower alcohols, volatile fatty acids, and/or humic acid. For aromatic feeds the main products are phenols (and derivatives), methane and carbon dioxide. The process is carried out in a slurry phase, at pH of 7.8, under moderate stirring using a bacteria concentration less than 20%. The feed concentration could not exceed more than 50%, as stated in the patent document. In the aerobic operation, the thermophilic consortium KSARC56 is operated for 48 hours at a temperature of up to about 60°C. For the anaerobic operation a mixture of N2 C02 of about 80 20 was used. 

Among the classes of feedstock processed in the hydrocracker the most highly aromatics feed are light cycle oils produced in the FCC unit Once formed by cyclization and the hydrogen transfer mechanism discussed above, they accumulate in the product due to the absence of a metal function in the FCC catalyst and adequate hydrogen in the process environment. They are typically sold as low-value fuel oil, or hydrotreated to reduce sulfur content and improve their quality as diesel blend stocks. Another approach to upgrade their value even further... 

BETA were axso run using a moderately aromatic feed (52.8% C, 26.9% and 20.3% C ) Detailed feed propertiis are given in Table II. 

Pilot Plant Results at 72 vol% Conversion Aromatic Feed, "A"... 

The coefficient of determination, R, of the dry gas yield model is 0.86 for catalyst A and 0.82 for the catalyst B. Based on the model, under the same operating conditions and for the same feed, catalyst B always makes more dry gas than catalyst A. Figure 12.16a and b shows dry gas yield predicted from H-NMR spectra versus dry gas yield measured by gas chromatography. For heavy aromatic feeds, shown by triangles, and feeds with high level of nickel and vanadium, indicated by squares, the model underpredicts dry gas yield. 

As the feed concentrations of aromatic contaminants are increased, low concentrations of gas-phase intermediate products are occasionally reported. During the photocatalytic oxidation of aromatic contaminants in the 25-500-ppm range, some researchers have observed up to several ppm of gas-phase intermediate products. For example, Ibusuki and Takeuchi [8] detected 1-2 ppm of benzaldehyde in the gas phase following photocatalytic oxidation of 80 ppm of toluene in a batch-reactor system. Even at moderate aromatic feed concentrations, gas-phase intermediate concentrations may be too low to be detected reliably. 

It should be kept in mind that, for this simple case, three coordination positions must be available on the Co for the mechanisms to proceed. If one or more of these coordination sites are occupied by a nonparticipating molecule such as an aromatic feed component or H2S, the rate of progress through this sequence will be reduced. Similarly, the DBT and H2 must be adsorbed to enter the sequence, and if competing molecules occupy coordination sites on Co, the rate of progress through the sequence will also be reduced. 

This relationship will vary with the aromatic content of the feedstock. With a highly aromatic feed, the catalyst with the higher hydrogenation activity may give a higher isobutane/n-butane ratio, although with the pentanes and hexanes the effect is reversed. 

Description Extractive distillation is used to separate close-boiling components using a solvent that alters the volatility between the components. An ED Sulfolane unit consists of two primary columns they are the ED column and the solvent recovery column. Aromatic feed is preheated with lean solvent and enters a central stage of the ED column (1). The lean solvent is introduced near the top of the ED column. Nonaromatics are separated from the top of this column and sent to storage. The ED column bottoms contain solvent and highly purified aromatics that are sent to the solvent recovery column (2). In this column, aromatics are separated from solvent under vacuum with steam stripping. The overhead aromatics product is sent to the BT fractionation section. Lean solvent is separated from the bottom of the column and recirculated back to the ED column. 

Catalysts Cyclic Metals Impregnation and steaming (CPS). Test Conditions MAT, fixed-bed, 527°C Reactor Temperature, 30 s Contact Time, Aromatic feed, 0.948 g/cc 15"C, R.I. 

Variables High temperature Low H20/CnHm No enhanced H20 adsorption Low activity Aromatic feed Low temperature Low H20/C Hm Low H2/C Hm Aromatic feed High temperature High void fraction Low H20/C Hm High pressure Acidity of catalyst... 

The greatest problem during thermal cracking arises from reactions involving aromatic feed. Aromatic compounds in the feed have a very high tendency to undergo polycondensation reactions that lead to coke formation. Coke formation decreases the yields of the desired gasoline and diesel fractions. One example of a polycondensation reaction is shown in reaction (6.7). 

Cfi Aromatic Reactions Without Hydrogen. In the present study, tire aluminophosphate molecular sieves have been used alone and with added platinum and hydrogen to isomerize Cs aromatic feeds. In an initial screening study, a series of large to medium pore size molecular sieves were evaluated for catalytic activity for m-xylene rearrangements at 1000° F without added metal and hydrogen. 

Octafining is a highly selective process which can efficiently process C8 aromatic feeds with high ethylbenzene contents. Prefractionation for... 

However, tetraethylene glycol is the best of the glycols studied (Figure 11). The solvent contains 3.9% water so that it also has a boiling point of about 140 °C. Benzene distributes quite favorably in tetraethylene glycol. The tie lines are rather flat. The data are at 100 °C only. Highly aromatic feeds can be treated also. 

Description The feed, either paraffinic or olefinic C -Cg fraction, is heated through heat exchangers and a furnace to the desired temperature. The vaporized feed is fed to the top of the aromatization reactor. There are two reactors in series are in operation, and the other two reactors are in regeneration or standby. The effluent from the bottom of the second reactor is fed to the aromatization feed/effluent heat exchanger. After the feed/effluent heat exchanger, the reactor effluent is further cooled by air coolers and trim coolers with cooling water and chilled water. This cold effluent is then sent to the aromatization effluent separator (low pressure) where the rich net gas stream is separated from the aromatic-rich liquid. 

Description The technology encompasses two main processing areas reactor section and product distillation section. In this process, Cg aromatics feed stream is first mixed with hydrogen. The mixed stream is then heated against reactor effluent and sent through a process furnace. The heated mixture is fed into the DX reaction unit, where EB is de-alkylated at very high conversion,k and xylenes are isomerized to equilibrium. 

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