Absorption fluid

Absorption recovers valuable light components such as propane/propylene and butane/ butylene as vapors from fractionating columns. These vapors are bubbled through an absorption fluid, such as kerosene or heavy naphtha, in a fractionating-like column to dissolve in the oil while gases, such as hydrogen, methane, ethane, and ethylene, pass through. Absorption is effectively performed at 100 to 150 psi with absorber heated and distilled. The gas fraction is condensed as liquefied petroleum gas (LPG). The liquid fraction is reused in the absorption tower. 

Blood and plasma samples are taken on cones for combustion, weighed, dried at room temperature, combusted and the 14C02 formed is directed into an absorption fluid. The subsequent radioactivity measurements are carried out after addition of scintillator to the samples. 

Venturi scrubbers are designed on the basis of the venturi flow-metering device. The flow channel is narrowed down so that the velocity will greatly increase at the throat. Then, as in the flow-metering device the flow channel widens ouf. For ease of fabricalion venturi scrubbers are designed with a rectangular cross section. The absorption fluid is injected into the Venturi at the throat where the velocity is the greatest. For particulate removal plain water could be used. As in the plate columns discussed above, for the simultaneous removal of particulate matter and sulfur dioxide, soda ash or caustic soda slurries could be used for absorption of the gas. Venturis are frequently used in conjunction with plate towers. They also serve as stand-alone removal devices in some cases. 

After the air is completely displaced from the apparatus by the NHg (air bubbles cease to emerge from the second Erlenmeyer flask), the Mg is heated at 800 to 850 C for four hours. The onset of nitride formation is recognized by incandescence of the Mg and the evolution of Hg. A high NHg flow must be maintained at the peak of the reaction to avoid sucking the absorption fluid into the reactor. Since the finished material always contains adsorbed NHg, heating in a Ng stream should be continued at the same temperature for 90 minutes. Because of the high moisture sensitivity of the material, bottling must be carried out with the usual precautions. 

Alloy 400 (NiCu30Fe, 2.4360) was used in three stages of the evaporator/crystallisa-tion unit for waste water from the absorption fluid of a flue gas desulphurisation plant at 364 K (91 °C) and a pH value of 8-10. A corrosion rate of 0.04 mm/a (1.57 mpy) was measured after an operating time of 4 years. The alloy was used because the previously fitted rubber-coated steel components required frequent repairs [74]. 

A unit operation represents a basic physical operation in a chemical process plant. Examples are distillation, absorption, fluid flow, heat transfer operations, evaporation, extraction, drying, crystallization, and filtration. Fundamentals pertaining to a given unit operation are the same regardless of its industrial applications. This is how pioneers came up with the term unit operation. 

It is a stand-alone unit with no circulating absorption fluid. 

Foams are used industrially and are important in rubber preparations (foamed-latex) and in fire fighting. The foam floats as a continuous layer across the burning surface, so preventing the evolution of inflammable vapours. Foams are also used in gas absorption and in the separation of proteins from biological fluids. See anti-foaming agents. 

Absorption Systems. Absorption refrigeration cycles employ a secondary fluid, the absorbent, to absorb the primary fluid, refrigerant vapor, which has been vaporized in the evaporator. The two materials that serve as the refrigerant—absorbent pair must meet a number of requirements however, only two have found extensive commercial use ammonia—water and water—Hthium bromide. 

The induction of systemic toxicity may involve a variety of complex interrelationships between the absorbed parent material, any conversion products, and their concentration and distribution in body tissues and fluids. The general pathway that a material may foUow after its absorption is shown schematically in Eigure 2. 

Diatomite has only weak adsorption (qv) powers but shows excellent absorption (qv) because of its stmcture and high surface area. Acids, Hquid fertilisers (qv), alcohol, water, oils, and other fluids are absorbed by diatomite. 

Ordinary diffusion involves molecular mixing caused by the random motion of molecules. It is much more pronounced in gases and Hquids than in soHds. The effects of diffusion in fluids are also greatly affected by convection or turbulence. These phenomena are involved in mass-transfer processes, and therefore in separation processes (see Mass transfer Separation systems synthesis). In chemical engineering, the term diffusional unit operations normally refers to the separation processes in which mass is transferred from one phase to another, often across a fluid interface, and in which diffusion is considered to be the rate-controlling mechanism. Thus, the standard unit operations such as distillation (qv), drying (qv), and the sorption processes, as well as the less conventional separation processes, are usually classified under this heading (see Absorption Adsorption Adsorption, gas separation Adsorption, liquid separation). 

The realization of sensitive bioanalytical methods for measuring dmg and metaboUte concentrations in plasma and other biological fluids (see Automatic INSTRUMENTATION BlosENSORs) and the development of biocompatible polymers that can be tailor made with a wide range of predictable physical properties (see Prosthetic and biomedical devices) have revolutionized the development of pharmaceuticals (qv). Such bioanalytical techniques permit the characterization of pharmacokinetics, ie, the fate of a dmg in the plasma and body as a function of time. The pharmacokinetics of a dmg encompass absorption from the physiological site, distribution to the various compartments of the body, metaboHsm (if any), and excretion from the body (ADME). Clearance is the rate of removal of a dmg from the body and is the sum of all rates of clearance including metaboHsm, elimination, and excretion. 

Drying is an operation in which volatile Hquids are separated by vaporization from soHds, slurries, and solutions to yield soHd products. In dehydration, vegetable and animal materials are dried to less than their natural moisture contents, or water of crystallization is removed from hydrates. In freeze drying (lyophilization), wet material is cooled to freeze the Hquid vaporization occurs by sublimation. Gas drying is the separation of condensable vapors from noncondensable gases by cooling, adsorption (qv), or absorption (qv) (see also Adsorption, gas separation). Evaporation (qv) differs from drying in that feed and product are both pumpable fluids. 

In most processes involving the absorption of a gaseous pollutant from an effluent gas stream, the gas stream is the processed fluid hence, its inlet condition (flow rate, composition, and temperature) are usually known. The temperature and composition of the inlet liq-... 

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