A Study On High Efficiency Inhibitor In The Water Treatment Of Boiler

With the home-made water sample having a total hardness of 7mmol/L and analkalinity of 3, 4, 5, 6mmol/L respectively, which is made by combining the deionizedwater and chemicals( such as CaCI2,MgCl2,NaHCO3) according to the quality of thewater used in boiler in Tianjin area, this paper examines the inhibitory rate of sodiumcarbonate(Na2CO3), ethylenediamine tetraacetic acid disodium salt (EDTA-Na2) andaminotrimethylenephosphonic acid (ATMP) with the standard hanging piece method.By comparing the result with the inhibitory efficiency of hydrolyzed polymaleicanhydride(HPMA), 1-hydroxyethylidene-1,1-diphonic acid(HEDP) and sodiumpolyacrylate (PAAS), we can get a conclusion that organic inhibitor has an inhibitoryefficiency far better than inorganic inhibitor. Among all the organic inhibitors weused, however, ATMP has the best inhibitory performance. On the basis of theanalysis above, we choose the ATMP as the major body of a compound inhibitor.After experimenting with diverse compound inhibitors, we argue that the mostefficient compound in dealing with the boiler water of Tianjin area is ATMP/Na2CO3=20.3/100.Additionally, this paper examines various factors influencing inhibitoryperformance, including water hardness, alkalinity, pH and the dosage of ATMP, andwe analyze the variance of inhibitory mechanism under different dosage. We examinethe influence posed on the surface of calcium carbonate crystal by inhibitor by usingthe transmission electron microscope, and we discover that ATMP can transfer regularcrystal into loose residua and can adhere to the surface of the particle of Ca2CO3,resulting in the increase of Zeta potential and the cease of the growth of calciumcarbonate crystal.The paper provides good theoretical base and abundant experimental data for thedealing of boiler water in Tianjin area.