Chemical process industries separation equipment

Distillation Columns. Distillation is by far the most common separation technique in the chemical process industries. Tray and packed columns are employed as strippers, absorbers, and their combinations in a wide range of diverse appHcations. Although the components to be separated and distillation equipment may be different, the mathematical model of the material and energy balances and of the vapor—Hquid equiUbria are similar and equally appHcable to all distillation operations. Computation of multicomponent systems are extremely complex. Computers, right from their eadiest avadabihties, have been used for making plate-to-plate calculations. 

Tanks are used in innumerable ways in the chemical process industry, not only to store every conceivable liquid, vapor, or solid, but also in a number of processing applications. For example, as well as reactors, tanks have served as the vessels for various unit operations such as settling, mixing, crystallization (qv), phase separation, and heat exchange. Herein the main focus is on the use of tanks as liquid storage vessels. The principles outlined, however, can generally be applied to tanks in other applications as well as to other pressure-containing equipment. 

The solids are thrown outwards against the wall of the vessel and then move away from the gas inlet and are collected in the conical base of the equipment. This separation process is very effective unless the gas contains a large proportion of solid particles less than 10 p in diameter and is equally effective when used with dust or mist-laden gases. The cyclone separators are obviously rubber lined to withstand wear at the velocity of gas and corrosion and are the most commonly used general purpose separator in the chemical process industry. 

So far the discussion has been specific to systems at constant temperature equivalently, pressure could be fixed and temperature and liquid phase composition taken as the variables. Although much experimental vapor-liquid equilibrium data are obtained in constant-temperature experiments, distillation columns and other vapor-liquid separations equipment in the chemical process industry are operated more nearly at constant pressure. Therefore, it is important that chemical engineers be familiar with both types of calculations. 

Solvents are extremely important to the chemical processing industries both as an enabler and as a major contributor to large waste volumes. Solvents are used in many different industries to process, manufacture, and formulate products. They are also used in various unit operations Hke separations (gas/Hquid, Hquid/Hquid, soHd/Hquid), in situations where the solvent facditates the reaction medium, or is only there to dissolve the reactants so each may come into intimate contact with the other and the reaction may proceed more rapidly to completion. Solvents are used to control reactivity through moderating heat transfer, to clean equipment Hke reactors and overheads, and as part of product formulations such as in paints, textiles, rubber, adhesives, and many other products. In fact, it is quite hard to imagine chemistry and chemical processing without solvents in one part of a process or another. 

The development of membrane ultrafiltration for the chemical process industry was described by Michaels (131), who reviewed the basic principles, equipment, and types of applications. The useful ranges of available separation processes for molecules and particles of different sizes were compared by Porter and Michaels (132). Available membranes were described with pores of uniform sizes of selected diameters over the range 1-20 nm (10-200 A). A bibliography of applications has been compiled (133). Equipment and information are available from a number of manufacturers, representing a wide range of apparatus design and membrane construction. 

Distillation is the most widespread separation method in chemical process industry. Since the equipment and utility costs are very high the synthesis of distillation columns and distillation sequences is important task. Whereas it is very difficult due to the complexity of structures and equilibrium models. 

In general, in industrial processes, the necessity of a separation operation occurs after the mixing/reaction operations. Therefore, the separation operation is an indispensable process for chemical engineering. The purpose of the separation process is different from that of the mixing process, and the purpose of separation is only to separate substances depending on the requirements. However, identical to the mixing phenomenon, the separation phenomenon is definitely a function of space and time. The separation equipment is classified into two groups ... 

The development and application of membrane separation processes is one of the most significant advances in chemical and biological process engineering in recent years. Membrane processes are advanced filtration processes which utilise the separation properties of finely porous polymeric or inorganic films [1,2]. Membrane separations are used in a wide range of industrial processes to separate biological macromolecules, colloids, ions, solvents and gases. They also have important medical uses, especially in renal dialysis. The world-wide annual sales of membranes and membrane equipment are worth in excess of 1 billion. 

Solvent Crystallization. Two processes, one utilizing acetone (Armour) and the other employing methanol (Emery), are well known. Using the latter, fatty acid is dissolved in 90 percent aqueous methanol in a 1 2 acid/ solvent ratio by the application of heat. The resulting solution is then cooled to H 5°C in a multi-tubular crystallization chamber equipped with scrapers for efficient heat transfer. The crystallized fatty acids are removed by filtration. The filter cake is melted and stripped of any residual solvent to yield the refined stearin fraction, and then the liquid stearin is converted to flakes or powder by a variety of processes, for example, chill roller, and the like. The mother liquor from the filtration is stripped to obtain the olein fraction. The separated stearin and olein fractions have a variety of commercial applications in both the chemical and food processing industries. 

In filtration processes the solids are separated from the liquid by passing (filtering) the slurry through some form of porous filter medium. Filtration is a widely used separation process in the chemical and other process industries. Many types of equipment and filter media are used, designed to meet the needs of particular applications. Descriptions of the filtration equipment used in the process industries and their fields of application can be found in various handbooks Perry et al. (1997), Dickenson... 

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