METHOD OF PREVENTING CORROSION OF METAL SURFACES OF APPARATUSES IN ACID MEDIA Russian patent published in 1998 - IPC

FIELD: corrosion protection. SUBSTANCE: method consists in adding passivating inhibitor to corrosive medium after preliminarily determining, under laboratory conditions, dependence of metal corrosion rate a_t on concentration of inhibitor in medium (C); representing this dependence graphically in the form of two rectangular regions; determining, from point of intersection of these regions, critical values of concentration of inhibitor (C_S) and metal corrosion rate a_is; and calculating permissible concentration of inhibitor (C₀) from the following formula: , where β is mass- transfer coefficient of inhibitor in direction from medium to metal surface, cm/s; L largest intrinsic parameter of an element of dead space (slot depth, pipe length, etc.), cm; d_e equivalent diameter of dead space element, cm; k coefficient of proportionality determined from equation for metal-medium chemical interaction; D diffusion coefficient of inhibitor in given medium, sq.cm/s. Application of this method provides reliable and economic protection of equipment in acid media, primarily against local forms of corrosion, which earlier could not be prevented effectively because of lack of necessary consideration of mass transfer of inhibitor in dead zones of medium. EFFECT: increased reliability of corrosion protection. 1 dwg