Fume Control Technology

The technology in the fume capture field Is not well developed, and performances of many capture systems are low and typically may be in the 30% to 60% range. There is a paucity of fundamental research and development in the fume capture field. In contrast, hundreds of million of dollars have iteen spent on research and development activities in the gas-cleaning area, which is mature and well developed. It is not uncommon to specify and to measure gas-cleaning equipment performances of over 99.9% colleaion efficiency. As shown in Eq. (13.75), the ovcTall fume control system performance is determined by the product of the capture efficiency and the gas-cleaning efficiency. This equation clearly shows the need to improve the efficiency of capture of the fume at the source in order to obtain significant improvements in the overall fume control system performance. 

Smoke from the factories was a constant element of the community s life. The aged zinc plant belched out prodigious amounts of fume and dust full of sulfur, zinc, lead, cadmium, and arsenic. Control technology existed—these emissions could be trapped in baghouses and electrostatic precipitators—but U.S. Steel, like its competitors, only installed these devices where it was profitable to do so. Thus the plant used the sulfur from its roasters to make acid and collected metallic fume from ore sintering. The sale of these by-products was vital to the economics of zinc making, a business whose personnel,... 

The proper management of dust collection follows a basic rule of any pollution control technology, namely that it is best to deal with a dust suspension as near to its source as possible, rather than after it has been diluted with gas from other sources. Thus, fume from a smelter should be treated in hoods immediately over the smelter, rather than in the general exhaust from the smelter building. 

The volatile organic components that are emitted in the gaseous effluent can be controlled by a variety of technologies including scrubbing techniques, granular-carbon adsorption and fume incineration. The specific technology is selected on a case-by-case basis. 

Sumitomo Chemical technology consists of a number of small changes to conventional Hall-Heroult electrolysis cells, which combine to cut power consumption to some 14,000 kWh/tonne from the normal experience of 16,000 to 18,000 kWh/tonne [16]. In addition to reduced power consumption, better emission control, extended cell life, and decreased labor requirements are also achieved by these changes. Better external cell insulation, changes in what is basically a Soderberg anode design, and better fume containment by cell skirt construction modifications provide these improvements. 

Figure 5.6 shows that pyrogenic manufacturing gives excellent control over particle size distribution and median particle size. These grades of fumed silica differ in properties and require a different technological approaches to their dispersion since small particle size filler is more difficult to disperse. At the same time, smaller particle sizes give more transparent products and better reinforcement. 

Fumed silica is widely used for the reinforcement of polydimethylsiloxane (PDMS) elastomers. The intermolecular interaction of the filler surface with the PDMS matrix controls this process [1, 2] so that understanding which factors influence the interaction at the filler/PDMS interface has become a crucial point for further development of the technology. Among the factors of interest there are the... 

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