Study On Corrosion Inhibition Of Hydrogenating Reactor Effluent Air Coolers

The corrosion mechanism of hydrogenating reactor effluent air coolers (REAC) system was systematically discussed. The paper mainly researched the effect of various technologcial conditions on the corrosive system of air coolers, the investigated conditions include concentration of corrosion inhibitor, corrosion factor (K_p), temperature, pH value and synergistic effect. on the base of which organic corrosion inhibitor of benzotriazole (BTA) was synthesized, and seeing about inhibition efficiency of BTA and its compounds. Results show that BTA and its compounds are excellent inhibitors for corrosive system of hydrogenating reactor effluent air coolers. The main research is as follows:1,With examining main parameter of corrosion factor (K_p) that resulted in the corrosion of air coolers, simulating hydrocracking corrosive system for reactor effluent air coolers, the effect of various technical parameters on corrosion of REAC was examined by means of CMB-1510B portable instantaneous corrosion rate meterage. Researchs indicate that there exists good synergistic effect between (NaPO₃)₆ and ZnSO₄ compounds in NH₄Cl corrosion solution; at the same time, also indicate that annual corrosion rate rises obviously with increase of corrosion factor, annual corrosion rate rises obviously with decrease of it when pH value changes in lower range, effect of high pH value on annual corrosion rate lessens on the whole.2,With o-phenylenediamine and NaNO₂ as materials, and acetic acid and water solution as solvent, by several processes such as diazotization, closed loop reaction, extraction and separation, repeated crystal and vacuum torrefaction, corrosion inhibitor of BTA was synthesized, and the infra-red analytic test was carried out for the product synthesized on above condition, the characteristic peaks indicate that the product is BTA.3,The paper evaluated inhibition efficiency of organic corrosion inhibitor of BTA by means of indoor static tole dispersion and CMB-1510B portable instantaneous corrosion rate meterage. Results show that BTA corrosion inhibitor don't fit high-temperature by itself, but have good inhibition efficiency, high-temperature or low-temperature, after compounding with Na₂MoO₄. BTA have attained excellent inhibition effect at little dosage; when its concentration was 9 mg/L, the values of inhibition efficiency of 316L and 20 steels were respectively up to 94.5% and 81.6%. Moreover, the analytic results of AES and SEM indicate that BTA could form protective film on metal surface which prevented depolarizing substances to transfer toward metal surface, and reduced corrosion rate of metal.4,By using online corrosion testing experimental equipment and simulating practical running conditions, inhibition efficiency of five kinds of corrosion inhibitors of BTA, Na₂MoO₄, Na₂CrO₄, ZnSO₄ and PBTCA was investigated under different simulative corrosion solution, different temperature and pH value. Results show that there exists good synergistic effect between corrosion inhibitor of BTA and its compounds, reduced effectively corrosion rate of metal surface, and offered scientific decision-making gists for reasonable solution of corrosion problem of reactor effluent air coolers for hydrocracking system.