A new method is reported to protect carbon steel pipelines for wet transport of sweet and sour gases from internal corrosion up to the top-of-the line (TOL) by using corrosion inhibitors. The method functions not only at turbulent gas flow but also at stratified flow and even under stagnant conditions. According to the TOL spreading inhibitor concept inhibitor molecules are transported with a spreading liquid film (produced by spreading-active compounds) against the gravity from the bottom-of-the-line (BOL) along the pipe wall to the TOL. The paper describes the universal applicability of this concept which works under all surface conditions encountered in sweet or sour wet gas transport lines. The surface can be metallic clean, covered with mill scale, rust or corrosion product scales. These surfaces can be dry, water wet or
hydrophobic. Careful tuning of the spreading system, composed of the 1- or 2-phase BOL liquid, the spreading agent and the corrosion inhibitor,
yields optimum corrosion protection on the entire pipeline surface also at high water condensation rates.
Keywords: Pipeline, corrosion, , inhibitors, surfactants, spreading films, stratified flow, top-of-the-line,carbon dioxide, hydrogen sulfide, sour gas