Coppers steam heated

Fluorine cannot be prepared directly by chemical methods. It is prepared in the laboratory and on an industrial scale by electrolysis. Two methods are employed (a) using fused potassium hydrogen-fluoride, KHFj, ill a cell heated electrically to 520-570 K or (b) using fused electrolyte, of composition KF HF = 1 2, in a cell at 340-370 K which can be electrically or steam heated. Moissan, who first isolated fluorine in 1886, used a method very similar to (b) and it is this process which is commonly used in the laboratory and on an industrial scale today. There have been many cell designs but the cell is usually made from steel, or a copper-nickel alloy ( Monel metal). Steel or copper cathodes and specially made amorphous carbon anodes (to minimise attack by fluorine) are used. Hydrogen is formed at the cathode and fluorine at the anode, and the hydrogen fluoride content of the fused electrolyte is maintained by passing in... 

Lead—copper alloys are also used as tank linings, tubes for acid mist precipitators, steam heating pipes for sulfuric acid or chromate plating baths, and flashing and sheeting (see Tanks AND pressure vessels). 

The discovery of aqua regia by the Arab alchemist Jabir Ibn Hayyan (ad 720—813) provided a new extraction technology. Amalgamation of silver in ores with mercury was extensively used during the late fifteenth century by the Spaniards in Mexico and BoLvia. In 1861 the complex ores of the Comstock Lode, Nevada, were ground together with mercury, salt, copper sulfate, and sulfuric acid, and then steam-heated to recover the silver. 

The copolymers have been used in the manufacture of extruded pipe, moulded fittings and for other items of chemical plant. They are, however, rarely used in Europe for this purpose because of cost and the low maximum service temperature. Processing conditions are adjusted to give a high amount of crystallinity, for example by the use of moulds at about 90°C. Heated parts of injection cylinders and extruder barrels which come into contact with the molten polymer should be made of special materials which do not cause decomposition of the polymer. Iron, steel and copper must be avoided. The danger of thermal decomposition may be reduced by streamlining the interior of the cylinder or barrel to avoid dead-spots and by careful temperature control. Steam heating is frequently employed. 

Figure 2.12 The sound of boiling methanol on a case Vs-in., horizontal, steam-heated copper tube at 1 atm. (From Westwater et al., 1955. Copyright 1955 by American Association for the Advancement of Science, Washington, DC. Reprinted with permission.)...

Fig. 3. Boiling curve for methanol. The liquid was outside a %-in., steam-heated, horizontal copper tube, at 1 atm. The letters represent the conditions for the photographs, Figs. 4 to 9 (W3).

Fig. 35. Effect of agitation. Methanol was agitated with a three-blade propeller while boiling at 1 atm. on a %-in. horizontal, steam-heated, copper tube. The shaft speed is indicated (P5).

Copper electric heating rods 1.0 in diameter are used to produce steam at 5-lb/in2-gauge pressure in a nucleate-pool-boiling arrangement where AT, = 4°C. Estimate the length of rod necessary to produce 2000 lb ,/h of saturated vapor steam. 

Water at 15 C is heated by passing it through 2-cm-inlemal-diametcr thin-walled copper tubes. Heat is supplied to the water by steam that condenses outside the copper tubes at 120 C. If water is to be healed to 65°C at a rate of 0.2 kg/s, detennine (a) the length of the copper tube that needs to be used and (b) the pumping power required to nvercomc pressure losses. Assume the entire copper tube to be at the steam temperature ofI20 C. 

To study the transition region, one must employ a hot fluid or a condensing vapor as the source of heat. Drew and Mueller (D3) obtained transition boiling data for six liquids boiling on a steam-heated copper... 

Fig. 3. Nucleate and transition boiling. Six liquids were boiled on a J-4-inch steam-heated, copper coil, at one atmosphere (D3).

Fig. 6. Effect of surface-active agent on transition boiling. Rohm and Haas Hyamine 1622 (benzyldimethyl 2-[2(p-l,l,3,3-tetramethylbutylphenoxy)ethoxy]-ethyl ammonium chloride mol. wgt. = 466) was added to methanol boiling on a Ji-inch, horizontal steam-heated, copper tube at one atmosphere (LI).

Fio. 7. Effect of surface texture on transition boiling. Methanol was boiled at one atmosphere on a %-inch, horizontal, steam-heated, copper tube (D2). 

A 40-liter tank full of water at 15 °C is to be heated to 50 4 C by means of a 1-cm-OD copper steam coil having 10 turns of 30 cm diameter. The steam is at atmospheric pressure and its thermal resistance is negligibly small Neglecting the heat losses from the tank, estimate the heating time required. Hint Assume the coil as a horizontal cylinder.)... 

Commercial acetic acid is principally manufactured on the large scale from acetate of soda, which yields a sufficiently strong and pnro acid for commercial purposes, without the trouble of rectification. In this process, shallow copper vessels formed without rivets or solder in those parts exposed to the action of the acid, are employed for the purpose of the di.stillatiou. A coil of drawn copper pipe, heated by steam, having a pressure of UO to I5 pound s to the inch, traverses the bottom of the apparatus. The refrigeratory consists of well cooled earthenware vessels, and the adopter or pipe connecting the still with the receivers is also of the same materials. Stills... 

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