Aromatic products recovery

The process consists of a reactor section, continuous catalyst regeneration unit (CCR), and product recovery section. Stacked radial-flow reactors are used to minimize pressure drop and to facilitate catalyst recirculation to and from the CCR. The reactor feed consists solely of LPG plus the recycle of unconverted feed components no hydrogen is recycled. The liquid product contains about 92 wt% benzene, toluene, and xylenes (BTX) (Figure 6-7), with a balance of Cg aromatics and a low nonaromatic content. Therefore, the product could be used directly for the recovery of benzene by fractional distillation (without the extraction step needed in catalytic reforming). 

Toluene, Benzene, and BTX Recovery. The composition of aromatics centers on the C - and Cg-fraction, depending somewhat on the boiling range of the feedstock used. Most catalytic reformate is used direcdy in gasoline. That part which is converted to benzene, toluene, and xylenes for commercial sale is separated from the unreacted paraffins and cycloparaffins or naphthenes by liquid—liquid extraction or by extractive distillation. It is impossible to separate commercial purity aromatic products from reformates by distillation only because of the presence of azeotropes, although complicated further by the closeness in boiling points of the aromatics, /o-paraffin, and unreacted C6, C -, and Cg-paraffins. 

Description The technology encompasses three main processing areas splitter, reactor and stabilizer sections. The heavy-aromatics stream (C9+s feed) is fed to the splitter. The overhead C9 aromatic product is the feed to the transalkylation reactor section. The splitter bottoms is exchanged with other streams for heat recovery before leaving the system. 

The bottoms stream from the stripper, substantially free of nonaromatic impurities, is sent to the recovery column (3) where the aromatic product is separated from the solvent. Because of the large difference in boiling point between the solvent and the heaviest aromatic component, this separation is accomplished easily, with minimal energy input. 

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. 

Description The process consists of a reactor section, continuous catalyst regeneration (CCR) section and product-recovery section. Stacked radial-flow reactors (1) facilitate catalyst transfer to and from the CCR catalyst regeneration section (2). A charge heater and interheaters (3) achieve optimum conversion and selectivity for the endothermic reaction. Reactor effluent is separated into liquid and vapor products (4). The liquid product is sent to a stripper column (5) to remove light saturates from the C6 aromatic product. Vapor from the separator is compressed and sent to a gas recovery unit (6). The compressed vapor is then separated into a 95% pure hydrogen coproduct, a fuel-gas stream containing light byproducts and a recycled stream of unconverted LPG. 

Description A typical SED unit mainly consists of an extractive distillation column and a solvent recovery column. The hydrocarbon feed is separated into non-aromatics and aromatics products through extractive distillation with the solvent. For the benzene-recovery case, benzene is directly produced from the SED unit. For the benzene and toluene recovery case, pure benzene and pure toluene are produced from the aromatics product of the SED unit through downstream fractionation. 

When the diacid chloride component has relatively high hydrolytic stability, completely or partially water-miscible solvents are particularly useful in the preparation of those aromatic polyamides which are frequently obtaii only in low molecular weight when water-immiscible solvents are used. Water miscible solvents accelerate the reaction rate, enhance polymer swelling and cilitate product recovery. Typical examples are cyclohexanone, 2,4-dimethyltetra-methylenesulphone, methylethylketone, tetramethylenesulphone, acetone, THF and isopropanol [20]. 

The effluent from the last reactor is cooled and sent to a separator. Part of the vapor is compressed and recycled to the reactors. The rest is compressed, combined with separator liquids, and sent to the product recovery section. Liquids from the recovery section go to a stabilizer, where light saturates are removed from the C6-plus aromatic products. 

A simplified flow diagram of a COSORB unit is shown in Figure 16-24. The overall pnKess generally includes (1) feed gas preparation, (2) carbon monoxide absorption (com-plexing), (3) carbon monoxide desorption (decomplexing), (4) aromatic solvent recovery from effluent gas streams, and (5) compression of CO product stream. Steps (1) and (5) are not shown on the flow sheet. 

In practice superheated steam is generally employed for substances with a low vapour pressure (< 5-1 mm.) at 100°. Thus in the recovery of the products of nitration or aromatic compounds, the ortho derivative e.g., o-nitrophenol) can be removed by ordinary steam distillation the... 

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