| Some saponified humic acids can serve as scale remover and scale inhibitor amid water treatment as they have two properties of removing and inhibiting scale as well as low corrosion rate. Using them in the cooling system of boiler and pipe network of oilfield flooding can save costs. In addition, by synthesizing some saponified humic acids, researchers hope that the application range and application value of humic acids can be broadened. In this paper, alkali liquor was atomized to spray on humic acid powder, so as to control the contact surface and reaction ratio, and enable the carboxyl in humic acid molecules to transform into sodium carboxylate group, thus achieving the goal of making humic acid dissolve in water and preserve more acidic group in humic acid. Moreover, the performance of some saponified humic acids for removing and inhibiting calcium scale was evaluated, and then the onsite scale sample and water sample were tested to evaluate the total scale removal rate and calcium scale inhibiting rate of some saponified humic acids. According to the experiment for removing and inhibiting calcium carbonate scale, the scale inhibiting rate is 77% when the saponification extent is 75.3%, the concentration is 60mg/L, and the temperature is 60℃; and the scale dissolving rate is over 90% within 4h when the saponification extent is 57.2%, the temperature is 60℃ and the concentration is 250mg/L. According to experiment for removing and inhibiting calcium sulfate scale, the scale inhibiting rate is 74% when the saponification extent is 75.3%, the concentration is 60mg/L, and the temperature is 60℃; and the scale dissolving rate is over 90% within 4h when the saponification extent is 57.2%, the temperature is 60℃ and the concentration is 200mg/L. Moreover, it has excellent anti-hardness as well as anti-interference performance against Ca2+, HCO3- and SO42-. According to the evaluation on the scale removal and inhibiting effect in the cooling system of boiler, the scale inhibiting rate is 72% and the total scale removal rate is 63.7% in 8h when the saponification extent is 75.3%, the concentration is 80mg/L, and the temperature is 60℃. According to the evaluation on the scale removal and inhibiting effect in the pipe network of oilfield flooding, the scale inhibiting rate is 65% and the total scale removal rate is 54% in 8h when the saponification extent is 75.3%, the concentration is 100mg/L, and the temperature is 60℃. The scale removal and inhibiting effect in the pipe network of oilfield flooding is not so good as in the cooling system of boiler, but the performance is stable in both of them. Moreover, scale removal and inhibiting rate can be adjusted by changing saponification extent, so as to adapt to production. |
