Oxygen in-service concentrations

Table 7-1 Experimental In-Service Oxygen Concentrations (ISOCs) and Out-Of-Service Fuel Concentrations (OSFCs)1...

ISOC is the in-service oxygen concentration in volume % oxygen, z is the stoichiometric coefficient for oxygen given in Equation 6-9, and LFL is the fuel concentration at the lower flammability limit, in volume percent of fuel in air. 

If the test is to be a guide for the selection of a material for a particular purpose, the limits of controlhng factors in service must be determined. These factors include oxygen concentration, temperature, rate of flow, pH value, and other important characteristics. 

It is often difficult to conduct laboratory tests in which both the environmental and stressing conditions approximate to those encountered in service. This applies particularly to the corrosive conditions, since it is necessary to find a means of applying cyclic stresses that will also permit maintenance around the stressed areas of a corrosive environment in which the factors that influence the initiation and growth of corrosion fatigue cracks may be controlled. Among these factors are electrolyte species and concentration, temperature, pressure, pH, flow rate, dissolved oxygen content and potential (free corrosion potential or applied). 

Draw a flammability diagram for n-butane. The experimentally reported LOC for n-bu-tane is 12%. What must the oxygen concentration be reduced to before pumping in butane What butane concentration must the vapor be reduced to before pumping air into the vessel before taking it out of service ... 

Oxygen control. In order to make measurements of oxygen activity in sodium the electrochemical control technique based on galvanic cell has been mastered with sodium flowing over electrolytic pellet of thorium and yttrium sealed into the metal tube. Reference electrode is located inside the tube. E.m. F. generated depends on the temperature and oxygen concentration e.m. F. = f (T, Co2). Service life of such device is over 10" hours. 

The employershall ensure that oxygen concentrations greater than 23.5% are used only in equipment designed for oxygen service or distribution. 

For aluminum, pitting corrosion is most commonly produced by halide ions, of which chloride (Cl ) is the most frequently encountered in service. The effect of chloride ion concentration on the pitting potential of aluminum 1199 (99.99-i-% Al) is shown in Fig. 6. Pitting of aluminum in halide solutions open to the air occurs because, in the presence of oxygen, the metal is readily polarized to its pitting potential. In the absence of dissolved oxygen or other cathodic reactant, aluminum will not corrode by pitting because it is not polar-... 

---