Inhibitors continued volatile

Gas wells corrode mostly in the reflux zone, which is an area of the well somewhere between the bottom and the wellhead, where condensation occurs. As the gas flows up the well, its temperature drops due to expansion, and this causes condensation when the temperature reaches the dew point of the gas. Volatile inhibitors such as formaldehyde and ammonia, injected into gas wells have been used successfully to inhibit corrosion. Many gas weUs today are protected by injecting amine inhibitors continuously, in batches, or by squeezing, which means they coat the well when injected and also enter the gas stream partially by vaporization and partially by entrainment. 

Reliable analytical methods are available for determination of many volatile nitrosamines at concentrations of 0.1 to 10 ppb in a variety of environmental and biological samples. Most methods employ distillation, extraction, an optional cleanup step, concentration, and final separation by gas chromatography (GC). Use of the highly specific Thermal Energy Analyzer (TEA) as a GC detector affords simplification of sample handling and cleanup without sacrifice of selectivity or sensitivity. Mass spectrometry (MS) is usually employed to confirm the identity of nitrosamines. Utilization of the mass spectrometer s capability to provide quantitative data affords additional confirmatory evidence and quantitative confirmation should be a required criterion of environmental sample analysis. Artifactual formation of nitrosamines continues to be a problem, especially at low levels (0.1 to 1 ppb), and precautions must be taken, such as addition of sulfamic acid or other nitrosation inhibitors. The efficacy of measures for prevention of artifactual nitrosamine formation should be evaluated in each type of sample examined. 

An important aspect of the efficiency of inhibited plastics is the stock of Cl in the polymer matrix. If the anticorrosion system is designated for longterm operation, a moment when the Cl stock appears to be fully exhausted inevitably arrives. Naturally, this substantially lowers the effectiveness of the anticorrosion system, although does not necessarily lead to failure. Types of rust-inhibiting plastics such as coatings and preserving films retain their barrier properties even after volatilization or wash-out of the inhibitors and continue to insulate metal goods from the hostile environment. 

The condition of sporostasis, where spores fail to germinate on account of inhibitors produced by the parent culture or cultures of another species, has been described by Robinson and Park (1966). This condition is sometimes found to depend upon the continuous production of a volatile substance by mycelium. 

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