| 摘要 |
<p>An acid gas is sepd. from a gas mixt. by means of an alkaline absorption soln.; the corrosion potential of a metal surface in contact with the absorption soln. (or a parameter which influences this potential) is measured and, when the measured value falls below a predetermined figure, ions capable of raising the redox potential in the absorption soln. are added in sufficient quantity to restore the measured value to the desired level. In the addn. a margin is introduced, i.e. the threshold value at which the introduction of ions commences is set at a potential considerably above, esp. 20 mV above, the value at which the metal surface becomes accessible to intergranular corrosion. The absorption soln. is pref. a potassium carbonate soln. contg. pref. 6-14 (0.1-1) wt.% arsenic ions. The process prevents stress corrosion, esp. a form of corrosion described as intergranular corrosion which takes plate due to dissolving out of the pearlite phase at the surface of the metal.</p> |
