Protection of petroleum gas pipes from corrosion - by flushing with petroleum gas contg. a 1,2,3-triazole

摘要

The inside of pipes used for the distribution of petroleum gas is protected against corrosion by passing petroleum gas contg. 5 x 10-6 (and pref. 150 x 10-6) g/l of a 1,2,3-triazole (I) in the vapour phase through the pipes at a flow rate of 60 (pref. 500) g/hr., the temp. of the pipes being kept at 50 degrees C (pref. 25 degrees C) during and after passage of the gas. This method is esp. useful for protecting copper piping in domestic and industrial heating systems fueled by liquid petroleum gas (LPG). The additive (I) is pref. a triazole contg. =1 benzene ring, esp. benzotriazole. In a prefd. embodiment, continuous protection is afforded by dissolving (I) in the LPG in an amt. (pref. 5-30 ppm) such that when the LPG evaporates at a rate of 60 g/hr., the (I) concn. in the vapour phase is =5 x 10-6 g/l.