Energy recovery industrial processes

Kenney (1984) reviews the application of thermodynamic principles to energy recovery in the process industries. 

In an industrial process there will be many hot and cold streams and there will be an optimum arrangement of the streams for energy recovery by heat exchange. The problem of synthesising a network of heat exchangers has been studied by many workers,... 

Figure 3.12. Reformed gas waste-heat boiler arrangement of vertical U-tube water-tube boiler (Reprinted by permission of the Council of the Institution of Mechanical Engineers from the Proceedings of the Conference on Energy Recovery in the Process Industries, London, 1975.)...

Barlow, J. A. (1975) Inst. Mech. Eng. Conference on Energy Recovery in the Process Industries, London. 

Industrially, the silver is recovered from either the wash water, or the bleach fix separately or from a mixture of the two using electrolysis employing a stainless steel cathode cylinder and an anode of stainless steel mesh. A typical wash solution composition contains silver (4 g L ), sodium thiosulphate (220 g L ), sodium bisulphite (22 g L ) and sodium ferric EDTA (4 g L ). At Coventry we have used a scaled down version of the industrial process employing 250 mL samples [46]. Electrolysis experiments were performed at ambient temperature with both wash and bleach fix solutions and in which the potential applied to the cathode and the speed of rotation of the cathode were varied. The sonic energy (30 W) was supplied by a 38 kHz bath. The results are given in Tab. 6.9. The table shows that the recovery of silver on sonication of the wash or bleach fix solutions is much improved especially if the electrode is rotated while ultrasound is applied. Yields with bleach fix (which contains ferric ions) are less since Fe and Ag compete for discharge (Eqs. 6.13 and 6.14). 

The prototype industrial process based on this concept is the Ruhrchemie-Rhone Poulenc process for the hydroformylation of propylene to butanal94,219,220 (see Section 7.3.1). Because of the use of appropriately modified water-soluble ligands, the catalyst resides and operates in the aqueous phase. The particular features of this process are the positive energy balance and easy catalyst recovery, namely, the simply circulation of the aqueous catalyst solution. New types of water-soluble Ir and Rh complexes with tris(hydroxymethyl)phosphine222 were described, and the biphasic hydroformylation of 1-hexene was accomplished in ionic liquids.223 A cationic sugar-substituted Rh complex displays high regioselectivity to branched aldehydes.224... 

CMCs are used in the manufacture of preheaters and recuperators in heat recovery equipment. They are used for indirect heating and energy-intensive industrial internal processes such as glass melters, steel reheaters and aluminium remelters. 

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