Also Energy efficiency

Apart from the coulometers described, there are also instruments in which products of electrolyses are determined by titration. The iodine coulometer is based upon the anodic liberation of iodine from solutions of potassium iodide, the iodine being determined by titration with thiosulphate. Besides current efficiency also energy efficiency /) is very important in technical practice. This is the ratio of theoretically required quantity of energy Wt to the quantity of energy Wt actually consumed for the electrochemical preparation of a given product (expressed as a percentage) ... 

Plastics are also energy-efficient compared with traditional materials [1]. It takes twice the weight of paper to effectively protect goods than in the case of polyethylene and if all the plastics currently used in packaging were to be replaced by paper, the effect on the environment would be catastrophic in terms of forest depletion, increased energy utilisation and damage to the environment [2,3]. This ecologically important characteristic of the polyolefins will be discussed in more detail in Section 4. 

It is also interesting to use Figure 6 to make a comparison of different aeration devices on the basis of energy-efficiency. From equation 6 and assuming a constant driving force... 

The principal producers of aluminum trifluoride in North America are Alcan, Alcoa, and AUiedSignal. It is also produced in other countries, eg, France, Mexico, Norway, Italy, Tunisia, and Japan. Total worldwide production of aluminum trifluoride in 1990 was 400,000 metric tons and the price was 1100/t. In 1993, because of excess recovery of fluorine values, use of energy efficient smelters, and the worldwide economic climate, the price was down to 750/t. 

The hquid-phase processes are more energy efficient than the vapor-phase processes, however, they iacur costiy high pressure equipment investment and also produce waste streams containing used catalyst (213). Both methods produce substantial quantities of by-products which cause refining difficulties. The by-products consist primarily of mesitylene [108-67-8] phorone [504-20-17, and the foUowiag xyUtone isomers (215) ... 

The second law can also suggest appropriate corrective action. Eor example, in combustion, preheating the air or firing at high pressure in a gas turbine, as is done for an ethylene (qv) cracking furnace, improves energy efficiency by reducing the lost work of combustion (Eig. 4). 

Two-fluid (see Fig. 14-87h). Gas impinges coaxially and supplies energy for breakup. High velocities can he achieved at lower pressures because the gas is the high-velocity stream. Liquid-flow passages can he large, and hence plugging can he minimized. Because gas is also accelerated, efficiency is inherently lower than pressure nozzles. 

A novel comminution device, the roll press, has achieved commercial success [Schoenert, International J. Mineral Processing, 22, 401-412 (1988)]. It is used for fine crushing, replacing the function of a coarse-baU mill or of tertiary crushers. Unlike ordinary roll crushers which crush individual particles, the roll press is choke fed and acts on a thick stream or ribbon of feed. Particles are crushed mostly against other particles, so wear is veiy low. Energy efficiency is also greater than in ball mills. 

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