Oxygen ingression

The second most common problem in HW heating systems after oxygen ingress probably is that of uncontrolled or excessive water loss. 

Under these conditions, because the neutralizing amine has no effect on oxygen ingress, it is common to supplement the neutralizing amine blend with a filming amine. Thefilmer may be applied separately (usually to a steam header) or blended with the neutralizers and added to the FW, or sometimes directly to the boiler. Care should be exercised when filmers are employed in previously corroded systems because it is very likely that old corrosion debris will be transported away to cause severe blockages in steam traps and valves. 

Similar considerations are relevant to protection of products that are labile to oxidative degradation. The permeability of plastic containers to oxygen ingress has also been evaluated, and is summarised in Table 2.9 [102]. 

Kontoudakis, N., Biosca, P., Canals, R., Fort, F., Canals, J., and Zamora, F. (2008). Impact of stopper type on oxygen ingress during wine bottling when using an inert gas cover. Aust. J. Grape Wine Res. 14,116-122. 

Lopes, P., Saucier, C., Teissedre, P.-L., and Glories, Y. (2006). Impact of storage position on oxygen ingress through different closures into wine bottles. /. Agric. Food Ghem. 54, 6741-6746. 

The long-shelf-life packs for aseptic products are often made of a board, foil, plastic (polyethylene) laminate which gives protection from oxygen ingress and... 

Inert system design The dryer atmosphere is commonly inerted with nitrogen, but superheated steam or self-inertized systems are also possible. Self-inertized systems are not feasible for flammable solvent systems. These systems must be operated with a small overpressure to ensure no oxygen ingress. And continuous on-line oxygen concentration monitoring is required to ensure that oxygen levels remain well below the explosion hazard limit. 

Assume that there is a pipeline whose age is 5 years with a downtime of 1 week. Biocide is routinely used in this pipeline. The pigging frequency in this pipe is 13 weeks. The fluid is stagnant, its temperature is 30°C, and both field and laboratory tests have confirmed the existence of mesophilic SRB. There is debris on the bottom of the pipe. Chemical analysis results are as follows Total dissolved solid (TDS) > 60 g/L, sulfate < 10 mg/L, total carbon from fatty acids < 20 mg/L, nitrogen (as utilizable N) < 5 mg/L, C-N ratio < 10, and prolonged oxygen ingress > 50 ppb. 

Basically, a high barrier to oxygen ingress in PET containers is needed not only to prevent the nticrobial growth and spoilage of the food, but also to preserve the quality of taste, aroma, color, and nutritimial values such as Vitamin C, all of which are... 

Fig. 19. 23 Schematics of typical O2 permeability rates top) and the net oxygen ingress in bottles made from PET-O2 scavenger blends...

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