Treatment Of Oily Wastewater And Its Resources Utilization

Most of oilfields have been in the mid-late period of development at domestic and there are some problems such as the bigger producing fluid volume, the higher water content, higher oil concentration and so on. So the polymer flooding of EOR (partially hydrolyzed polyacry la m -inde, PHP A) has been widely used in our country. At present, on one hand, polymer solution is prepared by fresh water then diluted by wastewater bringing about the wastement of water resources; meanwhile the wastewater may reduce the viscosity and has a bad influence on the flooding effect, on the other hand outword emission of large number of oily wastewater produced from the this process causes environmental pollution. Therefore the oily wastewater after treatment can be used to prepare polymer solution instead of fresh water in order to realize the resources utilization, decrescing environmental pollution because of outword emission of oily wastewater. In addition, abundant waste residue can be produced in case of water treatment by chemical methods. However the main component of such waste residue is calcium carbonate which can be used as industrial additive after been modified by modifier for example rubbler, plastic, drilling fluid. This valuable subject is preliminary explored in this thesis which can realize its resources utilization and lessen its harm on the environment.The research content and results of this thesis as follows:(1) The factors such as the inorganic ions, suspended particles and pH which have effects on the viscosity of polymer solution are systematically studied in order to find the main infulencing factors limitting the preparation of polymer solutrion by oily wastewater.(2) Treatment efficiency of oily wastewater by nano -microbubble technology, coagulation and coagulation/nano-microbubble is studied and the change of viscosity of polymer solution is also investicated systematically. The research aim is to study the the feasibility of nano -microbubble technology used to treat oily wastewater. The results shows that the mineralization, concentration of oil and suspended substance are reduced effectively after treatment, meanwhile, the viscosity of polymer solution prepared by treated water are increased significantly. Therefore nano-microbubble technology possesses tremendous development potential for oilfield wastewater recycling utilization. However the higher Treatment efficiency can be obtained when coagulation/nano-microbubble combined technology are employed to treat the oily wastewater treated.(3) In accordance with the high concentration of Ca2+,HCO3-, calcium carbonate is produced from wastewater. Then calcium carbonate produced from wastewater is modified by sodium stearate and titanate coupling agent. The results shows that activity of calcium carbonate is increased obviously and expected to be used as industrial additive.All the work and results of research will provide the basis for comprehensive treatment and resources utilization of oily wastewater.