Hydrocarbon coolant

Cooling is routinely appHed, either with ambient process water if THF is the solvent or with chilled brine if diethyl ether is used. Since Grignard reagents are particularly reactive with water, Hquid hydrocarbon coolants may be preferred, to eliminate the risk that could arise from a cooling-system leak. 

Optimization As stated previously, optimization studies should include the entire system. Such a study was made by Fair and BoUes [Chem. Eng., 75(9), 156 (1968)], using a hght-hydrocarbon system and with the objective of defining optimum reflux ratio. Coolants used were at —87, —40, and +30°C (—125, —40, and +85°F), corresponding to different pressures of operation and associated different condens-... 

Whenever a hydrocarbon backbone has two hydroxyl radicals attached to it, it becomes a special type of alcohol known as a glycol. The simplest of the glycols, and the most important, is ethylene glycol, whose molecular formula C2H4(OH)2. The molecular formula can also be written CHjOHCHjOH and may be printed as such on some labels. Ethylene glycol is a colorless, thick liquid with a sweet taste, is toxic by ingestion and by inhalation, and among its many uses is a permanent antifreeze and coolant for automobiles. It is a combustible liquid with a flash point of 240"F. 

Condensation of only part of a multicomponent vapour mixture, all components of which are theoretically condensable. This situation will occur where the dew point of some of the lighter components is above the coolant temperature. The uncondensed component may be soluble in the condensed liquid such as in the condensation of some hydrocarbons mixtures containing light gaseous components. 

These grades have been developed to give improved chemical resistance to automotive fluids such as gear lubricants, transmission and power steering fluids, engine oils, and rust inhibited engine coolants. Resistance to aromatic hydrocarbons is reduced. 

The fuel cell coolant system uses a liquid fluorinated hydrocarbon and transfers the waste heat from the cell stack through the fuel cell heat exchanger of the fuel cell power plant to the Freon-21 coolant loop system in the midfuselage. Internal control of the circulating fluid keeps the cell stack at an operating temperature of approximately 200°F. 

Since nitramine pyrolants are fuel-rich materials, the flame temperature decreases with increasing hydrocarbon polymer content The polymers act as coolants and generate thermally decomposed fragments as a result of the exothermic heat of the nitramine particles. The major decomposition products of the polymers are H2, HCHO, CH4, and When AP particles are incorporated into nitramine pyrolants, AP-nitramine composite pyrolants are formed. AP particles produce excess oxidizer fragments that oxidize the fuel fragments of the polymers that surround them. Thus, the addition of AP particles to nitramine pyrolants forms stoichiometricaUy balanced products and the combustion temperature increases. 

Single base" smokeless powder, developed mainly in the United States, uses only nitrocellulose. "Double base" smokeless powder, developed in Europe, is a blend of nitrocellulose and nitroglycerine. "Cordite," a British development, consists of 65% NC, 30% NG, and 5% mineral jelly. The mineral jelly (a hydrocarbon material) functions as a coolant and produces substantial amounts of CO 2, CO, and H 2O gas to improve the propellant characteristics. "Triple base" smokeless powder, containing nitroguanidine as a third component with nitroglycerine and nitrocellulose is also manufactured. 

Three processes are used commercially to make linear polyethylene-solution, slurry, and gas phase. All are called low-pressure processes (< 50 atm) to distinguish them from the free radical or high-pressure process that makes highly branched polyethylene. In the solution mode a hydrocarbon solvent at 125-170°C dissolves the polymer as it forms. The reaction usually slows as the solution becomes viscous because it becomes difficult to stir ethylene into the liquid phase. In contrast, The slurry process uses a poor solvent and low temperature (60-110°C) to prevent dissolving or even swelling of the polymer. Each catalyst particle creates a polymer particle several thousand times larger than itself. There is no viscosity limitation in the slurry method the diluent serves to transfer heat and to keep the catalyst in contact with ethylene and other reactants. Finally, the gas-phase process is much like the slurry method in that polymer particles are formed at similar temperatures. A bed of catalyst/polymer is fluidized by circulating ethylene, which also serves as a coolant. 

Fluorocarbons (FCs) Organic compounds analogous to hydrocarbons in which one or more hydrogen atoms are replaced by fluorine. FCs were once used in the United States as a propellant for domestic aerosols and are now found mainly in coolants and some industrial processes. FCs containing chlorine are called chlorofluorocarbons (CFCs). These are believed to be modifying the ozone layer in the stratosphere and are responsible for allowing more harmful solar radiation to reach the Earth s surface. 

A slush bath can be described as a low-melting-point liquid (typically a hydrocarbon solvent) that is being kept in a partially frozen state by either liquid nitrogen or dry ice. The temperature will remain constant as long as you continue to add liquid nitrogen, or dry ice, to the bath to maintain its slushy state. Table 6-3 is a comprehensive list of slush baths made of dry ice (C02) and liquid nitrogen (N2). Duplicate temperatures indicate a choice of solvent or coolant. 

Polychlorinated biphenyls (PCBs) are mixtures of biphenyls with 1 to 10 chlorine atoms per molecule. They are oily fluids with high boiling points, great chemical resistance, and low electrical conductivity, and have been used as plasticizers in polyvinyl polymers, insulators and coolants in transformers and heat exchange fluids. Dioxins and furans (see Section 9.1) are not produced intentionally but are derived from combustion processes of chlorinated aromatic hydrocarbons, pesticides and chlorinated solvents. 

A condensed version of the ERDL alkylation pilot plant flow plan is shown in Figure 4. Olefin and isobutane feed streams are separately pumped to the unit from large feed storage vessels with Lapp Pulsafeeder diaphragm pumps and metered with turbine flow meters. The streams are then combined, caustic scrubbed, water washed and dried with molecular sieves before being sent to the reactor. The combined feed stream is then injected into the acid-hydrocarbon emulsion in the stirred reactor vessel. In order to maintain a constant temperature environment both reactor and settler are coolant jacketed. 

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