Features of a Power System Incorporating Large AC Motors/Captive Transformers

Both synchronous and induction motors driving fans, pumps, and compressors (variable torque types of loads) may prove to be more economical and reliable when utilizing a lower voltage motor plus a captive transformer rather than a 13.8-kV motor. The economic factors, matching motor capabilities to load requirements, power system considerations, relaying and grounding systems possibilities, and operating experience with installed drives in Atlantic Richfield's Philadelphia Refinery are covered.     

Electrostatic Precipitators on Clinker Coolers

The art of using electrofilters on clinker cooler gases has now progressed sufficiently, and enough operating data are available to offer electrofilters as a highly efficient collector capable of meeting the most rigid emission codes.     

Corrosion inhibition of steel by hydrazine

The corrosion inhibition of steel in a closed system containing hydrazine at room temperature has been established. The steady-state potential measurements as well as weight loss measurements agree in indicating that hydrazine was found to behave in a similar manner to anodic inhibitors. A sharp ennoblement of potential occurs at concentration of 10^?2M accompanied by complete protection. The mechanism of inhibition by hydrazine is assumed to be due to its preferential adsorption on the local anodes inducing anodic polarization. After a certain critical concentration of hydrazine is reached complete blocking of the pores occurs which causes complete inhibition. For hydrazine-sulphate or hydrazine-chloride mixtures, a linear relationship is found between log hydrazine concentration and log maximum tolerated concentration of the aggressive ion. For hydrazine-sulphide mixtures, a concentration of 5 × 10^?2M hydrazine could tolerate a wide range of concentrations of sulphide ions.     

Korrosion von silber in neutralen alkalisulfatschmelzen

The corrosion of silver in the ternary eutectic of (mole %) 78 Li₂SO₄, 13·5 K₂SO₄ and 8·5 Na₂SO₄ at 625°C is proportional to the oxygen pressure above the melt. The corrosion current density of completely immersed specimens is 1·4 × 16^?6 A cm^?2 in the unstirred melt under a 100% oxygen atmosphere. The corrosion rate is increased by stirring.Specimens incompletely immersed in the melt are corroded at a much higher rate than fully immersed specimens. The specimen surface protruding from the melt is covered by a thin film of the molten material. Local cells are formed where O₂ is preferentially reduced on the surface above the melt, and silver is preferentially dissolved from the immersed portion of the surface. The corrosion current density is controlled by the ratio of areas inside and outside the melt.