Problems in Insuring Maintenance of Transport Systems of Fluid Hydrocarbons Through Metal Pipes

Abstract The structural continuity of the and the integrity of the metallic materials specific of pipelines guarantees their exploitation under proper technical conditions and with the minimum reduction of environmental risks, representing a permanent preoccupation and essential condition in the maintenance of the transport systems of fluid hydrocarbons through metallic pipes. Metallic and non-metallic materials coming in contact with a certain environment suffer gradual degradation due to reciprocal interaction. The nature of this interaction can be chemical or electrochemical and this, in time, makes the material unusable due to the structural, dimensional or continuity changes. The resistance to corrosion of a metallic material is closely related to the composition and its structure, to its degree of purity, to the nature and characteristic of the corrosive environment, to the conditions in which the corrosion takes place. When there is uniform corrosion, the behavior of the material is evaluated by the gravimetric index, the penetration index and the volumetric index. The protection against corrosion represents the total measures taken to diminish the destructive action of the environment on materials in working concrete conditions, at the lowest possible cost and by meeting safety conditions. The main means of protection or reduction of the corrosion intensity are the following: treatment of the environment (with the purpose of reducing its aggressivity), coating of the surfaces exposed to the corrosion, application of surface treatments, moving the electrochemical potential of the metal in the field of immunity or passaging and draining of dispersion currents. The displacement of the potential of the metallic material protected in the field of immunity can be ensured by the realization of a galvanic pile with an active anode or by current injection, which opens, as an engineering practice, the way to ensuring the cathodic protection applied to the equipments in contact with an electrolyte (water, oil etc.), as the most modern method of preventing the loss of metallic material and of structural damage of the pipes destined for the transport of fluid hydrocarbons.