To produce

Since process design starts with the reactor, the first decisions are those which lead to the choice of reactor. These decisions are among the most important in the whole design. Good reactor performance is of paramount importance in determining the economic viability of the overall design and fundamentally important to the environmental impact of the process. In addition to the desired products, reactors produce unwanted byproducts. These unwanted byproducts create environmental problems. As we shall discuss later in Chap. 10, the best solution to environmental problems is not elaborate treatment methods but not to produce waste in the first place. 

The preference is for a process based on ethylene rather than the more expensive acetylene and chlorine rather than the more expensive hydrogen chloride. Electrolytic cells are a much more convenient and cheaper source of chlorine than hydrogen chloride. In addition, we prefer to produce no byproducts. 

The solid particles are fluidized by air and fuel, which are fed to the bed and burnt to produce the high temperatures necessary for the reaction. 

Figure 3.5 shows centrifuges in which a cylindrical bowl is rotated to produce the centrifugal force. In Fig. 3.5a, the cylindrical bowl is shown rotating with a feed consisting of a solid-liquid mixture admitted at the center. The feed is immediately thrown outward toward the walls of the container. The particles settle horizontally... 

Figure 3 A centrifuge uses a rotating bowl to produce centrifugal force.

The ability to produce high product purity. Many of the alternatives to distillation only carry out a partial separation and cannot produce pure products. 

Also, although there are no selectivity data for the reaction, the selectivity losses would be expected to increase with increasing conversion. Complete conversion would tend to produce unacceptable selectivity losses. Finally, the reactor volume required to give a complete conversion would be extremely large. 

An arrangement is to be chosen to inhibit the side reaction, i.e., give low selectivity losses. The side reaction is suppressed by starving the reactor of either monochlorodecane or chlorine. Since the reactor is designed to produce monochlorodecane, the former option is not practical. However, it is practical to use an excess of decane. 

Consider a three-product separation as in Fig. 5.11a in which the lightest and heaviest components are chosen to be the key separation in the first column. Two further columns are required to produce pure products (see Fig. 5.11a). However, note from Fig. 5.11a that the bottoms and overheads of the second and third columns are both pure B. Hence the second and third columns could simply be connected and product B taken as a sidestream (see Fig. 5.116). The arrangement in Fig. 5.116 is known as a prefractionator arrangement. Note that the first column in Fig. 5.116, the prefractionator, has a partial condenser to reduce the overall energy consumption. Comparing the prefractionator arrangement in Fig. 5.116 with the conventional... 

Within each temperature range the streams are combined to produce a composite hot stream. This composite hot stream has a CP... 

Impurities in the feed materials can undergo reaction to produce waste byproducts. 

The best solution to effluent problems is not to produce the waste in the first place, i.e., waste minimization. If waste can be minimized at the source, this brings the dual benefit of reducing waste treatment costs and reducing raw materials costs. 

The inability to produce high-quality effluents is one significant disadvantage. Another disadvantage is that anaerobic processes must be maintained at temperatures between 35 and 40°C to get the best performance. If low-temperature waste heat is available from the production process, then this is not a problem. 

One advantage of anaerobic reactions is that the methane produced can be a useful source of energy. This can be fed to steam boilers or burnt in a heat engine to produce power. 

Aerosol sprays consist of a material dissolved or suspended in a liquid which when pressure is released volatilizes to produce a fine spray. The spray carries the active material. Used in hair lacquers, paints, etc. the propellant should be inert and non-inflammable. Chlorofluorocarbons have been used extensively but are now being replaced. 

Me2NCH2) C2H5)(Me)C-OOC Ph-HCI. Colourless crystalline powder with a bitter taste, m.p. 177-179"C. Prepared by the action of ethyl magnesium bromide on dimethyl-aminoaceione. It is a local anaesthetic, mainly used to produce spinal anaesthesia. 

Arosolvan process A process for the extraction of benzene and toluene from a mixture of aromatic and saturated hydrocarbons using a mixture of water and N-methylpyrrolidone. The process is used when naphtha is cracked to produce alkenes. To prevent extraction of alkenes these are saturated by hydrogenation prior to extraction. 

If light nuclei can be induced to fuse together to produce heavier nuclei, energy will again be... 

Fuel cells involve use of gaseous reactants to produce electricity - most often H2-O2 within a porous electrode. Secondary cells are rechargeable. The most important systems are... 

This cement is very resistant to attack by sulphates, sea water and acid waters. It is also used with crushed firebrick to produce refractory concrete. 

Fischer-Tropsch reaction The catalytic reaction of hydrogen and carbon monoxide (synthesis gas ) to produce high-molecular weight hydrocarbons. 

Jahn-TeHer effect The Jahn-Teller theorem states that, when any degenerate electronic slate contains a number of electrons such that the degenerate orbitals are not completely filled, the geometry of the species will change so as to produce non-degenerate orbitals. Particularly applied to transition metal compounds where the state is Cu(II)... 

Morphine and its salts are very valuable analgesic drugs but are highly addictive. In addition to suppression of pain, morphine causes constipation, decreases pupillary size and depresses respiration. Only the (-l-)-stereoisoraer is biologically active. They appear to produce their effects on the brain by activating neuronal mechanisms normally activated by... 

KCl —NaCl —MgS04) and in many brines. Separated by fractional crystallization, soluble water and lower alcohols. Used in fertilizer production and to produce other potassium salts. 

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