Regenerators high efficiency

The overall benefits of this high efficiency combustor over a conventional bubbling- or turbulent-bed regenerator are enhanced and controlled carbon-bum kinetics (carbon on regenerated catalyst at less than 0.05 wt %) ease of start-up and routiae operabiUty uniform radial carbon and temperature profiles limited afterbum ia the upper regenerator section and uniform cyclone temperatures and reduced catalyst iaventory and air-blower horsepower. By 1990, this design was well estabUshed. More than 30 units are ia commercial operation. 

FIG. 17-24 Modem FCC unit configured for high-efficiency regeneration and extra catalyst cooling. (Reptinted with peimission of UOF. RCC is a service ma7k of Ashland Oil Inc.)... 

Feedstock A higher fraction of 1,050°F+ (565°C+) in the feed. For many refiners, the regenerator temperature is the limit on addition of heavy ends to the feed. High-efficiency feed nozzles can be used. Naphtha quench can be added. 

The last reaction cited above as shown is very effectively catalyzed by bacterial action but is very slow chemically by recycling the spent ferrous liquors and regenerating ferric iron bacterially, the amount of iron which must be derived from pyrite oxidation is limited to that needed to make up losses from the system, principally in the uranium product stream. This is important if the slow step in the overall process is the oxidation of pyrite. The situation is different in the case of bacterial leaching of copper sulfides where all the sulfide must be attacked to obtain copper with a high efficiency. A fourth reaction which may occur is the hydrolysis of ferric sulfate in solution, thus regenerating more sulfuric acid the ferrous-ferric oxidation consumes acid. 

The reduced form of diphosphopyridine nucleotide (DPNH), which is used in the reduction of di-O-phosphoglyceronic acid to O-phosphoglycerose, could be regenerated with high efficiency from the oxidized form (DPN ) by the reduced form of 6-thioctic acid, thus supplying the necessary re-... 

Filtration is an efficient and inexpensive method for removing dust, particulates and bioaerosols from indoor air. High efficiency filters can remove up to 95 % of airborne particles as small as 0.3 microns. However, odor associated with gaseous VOCs cannot be removed by simple filtration and must be captured using adsorbents such as activated carbon and charcoal. Frequent replacement is needed since these adsorbents have finite capacity and cannot be regenerated. The aim of this project is to develop an effective remediation technology for common airborne VOCs found indoor. 

The physical solvents shown in Table I operate by dissolving the acid gases in the absorbing medium at elevated pressures and low temperatures. Regeneration of the solvent is principally by reduction of pressure, although heating is often necessary in high-efficiency applications, where H2S is to be removed to a few ppmv (3). 

Until very recently, high-efficiency chloroplast transformations have been limited to Chlamydomonas and the higher plant Tobaccum. Arabidopsis chloroplasts have been successfully transformed, but none of the regenerated transformed plants were fertile. Chloroplasts from potato leaf cells and rice suspension cells have also been transformed but with poor efficiency as well, and no fertile plants were recovered (Khan et al., 1999 Hibbard et al., 1998). Therefore, a major hurdle is the development of fertile, transgenic, economically important plants. 

Y. Ichikawa, J. L.-C. Liu, G.-J. Shen, and C.-H. Wong, A highly efficient multienzyme system for the one-step synthesis of sialyl trisaccharide In situ generation of sialic acid and TV-acetyllactosamine coupled with regeneration of UDP-glucose, UDP-galactose, and CMP-sialic acid, J. Am. Chem. Soc. 113 6300 (1991). 

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