Antiscale Technology Research On Thereuse Of Advanced Softening Heavy Oil Wastewater Without Desilication In Boiler

Most of the heavy oil was explored by steam stimulation and steam flooding in Liaohe Oilfield, which generated large volumes of heavy oil wastewater. The volumes of heavy oil wastewater were increased with changing the way of thermal recovery of heavy oil and prolonging production period. The components of heavy oil wastewater are complex, and the wastewater has a higher temperature and viscosity, in addition, the density difference of oil and water is small and the emulsification is serious. Thus, the heavy oil wastewater is nonbiodegradable and is difficult to be disposed. However, the reasonable method for disposing the heavy oil wastewater is one of the stubborn problems in oilfields.Reusing the heavy oil wastewater as boiler feedwater was implemented in Liaohe Oilfield by advanced treatment. The removal of oil and suspended solids, desilication, and softening were the main treatment process. Oil and suspended solids processing technology have been mature and the processing cost is low. However, lots of desilication agents were added in the desilication process resulting in a mass of silicon sludge and high cost, which could enormously pollute the environment. To reduce the environmental pollution and save water resources, based on the research of pilot test, reusing the advanced softening heavy oil wastewater without desilication as boiler feedwater was conducted via a pilot-scale test.As is well known, the wastewater quality would make very large changes due to the advanced softening and desilication. In this paper, according to the mechanism of antiscale in boiler the characteristics of scale were discussed after the 10000 m3 injection volume in the pilot-scale test. Most of the two and three valence metal cations are removed by advanced softening, which could react with silicates to form scales. By comparing the effect of the advanced softening with traditional technology which is general softening with desilication on the characteristics of scales, it further demonstrates that it is feasible for controlling scales to reusing the advanced softening heavy oil wastewater without desilication as boiler feedwater. In addition, controlling the corrosion of tube could reduce the scale according to the results. However, it is important for disposing large volumes of heavy oil wastewater, protecting environment and saving water resources. It also offers an important reference for engineering applications.