The Influence Factors Of Pipeline Scaling And Selection Of Scale Inhibitors

The aim of this study was to solve the serious scaling problem of injection water and brine pipline in Jianghan Oilfield General Salt Chemical Plant.In view of each kind of construction crystal ion and the material characteristic of injection water and brine in the plant,the scaling tendency of calcium carbonate and calcium sulfate was explored.In addition,the thesis discussed the measures and conditions of antiscaling-descaling technology to the pipelines of the plant.This result was also applicable to other similar production systems.The analyzed results by the X-ray diffraction:?1?The scale of injection water pipline contains calcite,halite,gypsum,few silicate and barite,?2?The scale of brine is gypsum,which is difficult to move.The water samples's characteristics and components were studied by means of chemical analysis and instrumental analysis.The results showed that there was a possibility to produce calcium carbonate scale and calcium sulfate scale.The Davis-Stiff saturation index method and Ryznar stability index method of calcium carbonate scale prediction showed that the injection water had the CaCO₃ scaling tendency.The Saturated coefficient method of calcium sulfate scale prediction showed that the injection water and brine had the CaSO₄?2H₂O scaling tendency.According to the practice problem of scaling in the plant's brine pipes,the thesis systemic researches the effect of NaCl concentration,temperature and other factors on the calcium carbonate solubility?Ksp?and the calcium sulfate solubility?Ksp?.According to the result of the analysis and the literature^[12],The system's pH value below and close to 7.00,calcium carbonate scale will not generate.ZC-1 inhibitor has high anti-scaling rate of calcium sulfate scale.The optimal conditions of ZC-1 use:Calcium ion concentration is0.01442mol?L^-1,the dosage of scale inhibitor is 20 mg?L^-1,higher holding temperature,the soaking time is 25 hours,pH is not necessary to be adjusted for it has little changes with or without scale inhibitor.Finally the scale inhibition efficiency of calcium sulfate in brine was explored.