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Petrochemical Processing crystallization

For example, when we consider the design of specialty chemical, polymer, biological, electronic materials, etc. processes, the separation units are usually described by transport-limited models, rather than the thermodynamically limited models encountered in petrochemical processes (flash drums, plate distillations, plate absorbers, extractions, etc.). Thus, from a design perspective, we need to estimate vapor-liquid-solid equilibria, as well as transport coefficients. Similarly, we need to estimate reaction kinetic models for all kinds of reactors, for example, chemical, polymer, biological, and electronic materials reactors, as well as crystallization kinetics, based on the molecular structures of the components present. Furthermore, it will be necessary to estimate constitutive equations for the complex materials we will encounter in new processes. [Pg.537]

Ammonium sulfate is produced as a caprolactam by-product from the petrochemical industry, as a coke by-product, and synthetically through reaction of ammonia with sulfuric acid. Only the third process is covered in our discussion. The reaction between anunonia and sulfuric acid produces an ammonium sulfate solution that is continuously circulated through an evaporator to thicken the solution and to produce ammonium sulfate crystals. The crystals are separated from the liquor in a centrifuge, and the liquor is returned to the evaporator. The crystals are fed either to a fluidized bed or to a rotary drum dryer and are screened before bagging or bulk loading. [Pg.64]

Since the early 1970s p-xylene has grown to become a large volume petrochemical. It is used primarily for the production of polyester fibers, films and resins, such as PET (polyethylene terephthalate) [7]. Demand for p-xylene has increased tenfold since 1970 to about 26xl0 t/year. Almost all of this additional production has been by the UOP Parex process as shown in Figure 7.1. A baseline production ofp-xylene is maintained by crystallization based sites that existed before the SMB adsorptive separation technology was established [8]. [Pg.231]

CRYSTALLIZATION PROCESSES addressed in this discussion are used in the chemical, petrochemical, pharmaceutical, food, metals, agricultural, electronics, and other industries. Moreover, the principles of crystallization are important in all circumstances in which a solid crystalline phase is produced from a fluid, even when the solid is not a product of the process. Much has been done... [Pg.194]

Separation processes are not only of great importance in refineries, but also in the chemical, petrochemical, gas processing, and pharmaceutical industries. Although the reactor can be regarded as the heart of a chemical plant, in most cases, 60-80% of the total cost is taken up by the separation step. This step involves one or more thermal separation processes such as distillation, extraction, absorption, crystallization, adsorption, membrane processes, c/c., which are used to obtain the products at the required purity. [Pg.76]

Various processes have been developed by Chevron, Shell, Sinclair, Southern Petrochemical, etc., and particularly by IC1 (Imperial Chemical Industries), Maruxen (XIS process), which operates in the presence of steam at a ratio of 0.03 to 0.13 mol/ mol of xylenes feedstock, and ARCO, which proposes the permanent regeneration of its catalyst by using the moving bed technology. These processes are usually combined with a p-xylene recovery technique, generally by crystallization. The isomerization yield depends on the ethylbenzene content at the reactor inlet and on the desired target product, either p-xylene alone or o- and p-xy]enes simultaneously. [Pg.282]

Paraxylene - ExxonMobil Chemical Technology Licensing LLC Paraxylene - UOP LLC, A Honeywell Company Paraxylene - UOP LLC, A Honeywell Company Paraxylene (PX-Plus XP Process) - UOP LLC, A Honeywell Company Paraxylene, crystallization - GTC Technology Petroleum coke, naphtha, gasoil and gas - China Petrochemical Technology Co., Ltd. [Pg.4]

Large-scale crystallization by freezing has been practised commercially since the 1950s when the first successful continuous column crystallizers were developed for use in the petrochemicals industry, particularly for -xylene. Some of these processes have already been discussed in section 8.2.2. The present section will be devoted to the freezing of aqueous systems and the removal of water, as ice, either as the required product or as the unwanted component of the mixture. [Pg.398]

Conventional chemical plants can usually be divided into a preparation, reaction, and separation step (see Figure 5.1). Although the reactor can be considered as the heart or the central unit of the chemical plant, of ten 60-80% of the total costs are caused by the separation step, where the various thermal separation processes are applied to obtain the products with the desired purity, to recycle the unconverted reactants and to remove the undesired by-products. Because of the many advantages (energy used as separating agent, high-density differences between the two fluid phases (liquid, vapor)) in 90% of the cases distillation processes are applied in the chemical or the petrochemical industry, whereas in the pharmaceutical industry crystallization processes are far more important (1). [Pg.177]

Aromatics [benzene, toluene, and xylene (BTX)] are obtained from refinery and petrochemical light naphtha streams. Aromatics are produced in the reforming process and in steam cracking. Extraction or various extractive distillation processes are used to isolate and separate aromatics from the naphtha streams. Typical extraction processes are based on tetraethylene glycol, sulfolane, N,N -methylpyrolidene, or morpholine. They produce a mixture of aromatics that are subsequently separated by distillation, extractive distillation, or—in the case of xylene isomers—differential adsorption or fractional crystallization. [Pg.718]

Membrane processes are very important in our everyday life, but also in industry, for example, for water and waste water treatment, in medical applications, or separation of petrochemicals. Membrane processes are an energy saving method for the separation of mixtures, which occur in nearly all production processes in the chemical industry. Membrane-based devices are much smaller and work at lower temperatures compared to conventional separation facilities with distillation, extraction, or adsorption processes. Classical separation methods used for purification of chemical products, notably distillation, extraction, and crystallization are energy and cost intensive. Over 50% of the energy costs in the chemical industry are used for the separation of gaseous or liquid mixtures. With membrane technology, the costs for difficult separations, for example, of azeotropic mixtures. [Pg.403]


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