The corrosion of metal equipment in unified oil processing units is under the influence of an unstable oil, light organic acids of bottom and condensed water containing emulsified hydrocarbons, dissolved salts and corrosive gases such as hydrogen chloride (HCl), carbon dioxide (CO2) and hydrogen sulfide (H2S). Corrosion destruction of the metal equipment at of unified oil processing units is the most severe to condensation cooling equipment of the units.
Another complex problem that accompanies the preparation of unstable oil in the unified oil processing unit, is deposits in the metal equipment of the unified oil processing units, which accumulate on the trays of distillation columns and which cannot be removed by periodic flushing with water. Deposits on metallic equipment in the unified oil processing units, are a mixture of clay minerals and fine sand, "cemented" hardness salts - carbonates and sulfates of calcium and magnesium. Despite the fact that the deposition of metal equipment in the unified oil processing unit are very tightly bound to the metal surface, they are very porous and does not impede access to the metal equipment at the facilities of the unified oil processing unit produced water contained in the unstable oil, where dissolved corrosive salts and gases: CO2 and H2S. The result is a rapid growth of the local types of corrosion under a layer of sediment (pitting, ulcers, through-holes).
To protect against corrosion of metal equipment in the installations of complex preparation of oil, the most simple, effective and economical method is the combined use of acid gas scavengers and corrosion inhibitors.
To prevent the formation of deposits in the metal equipment at unified oil processing unit are used fine filters to remove mechanical impurities in the unstable oil supply line in the unified oil processing unit. The use of filters has disadvantages. This needs for frequent replacement due to clogging by fine sand and clay sediments.
To provide the most effective protection against corrosion of metal equipment in the unified oil processing units, as corrosion inhibitors should be used polyfunctional corrosion inhibitors, film type, soluble in oil and hydrocarbons. Multifunctional corrosion inhibitors must be supplied to head lines of columns. Such corrosion inhibitors form on the metal surface of condensation and cooling equipment the protective resistant film of "sandwich" type, and prevents access to the metal condensation water with dissolved in it gases HCl, CO2 and H2S. Besides reliable protection of metallic equipment for unified oil processing units, feeding of polyfunctional inhibitor into column head leads to the removal of organic and mechanical deposits, including the products of corrosion from internal surfaces of the column and bottom column plates and the column bottom. To protect the metal equipment of unified oil processing unit form the mineral and clay-sand deposits, a very efficient purification method is a method of feeding into unstable oil, which comes to the unified oil processing units, of the same multifunctional corrosion inhibitor, as in column head. Sorbing onto the metal surface of columns in the unified oil processing units, polyfunctional corrosion inhibitor on the one hand, reduces the adhesion of clay-sand minerals on its equipment, and on the other hand, the sorbing directly on the clay surface and sand, polyfunctional corrosion inhibitor prevents their deposition and "cementation" on the metal surface of the column of the unified oil processing units with hardness salts (sulphates, carbonates).