Study On High Efficiency Clarifier Of Sewage For Thermal Recovery Wastewater Of Heavy Oil

At present, steam injection heat was the most important method for heavy oil recovery inthe world. With the gradual and further study of oil and gas field development, steaminjection heavy oil development would produce large amounts of heavy oil sewage.According to the characteristics of heavy oil thermal recovery sewage, this paper researchedsystematically the factor of oil-water separation from the aspect of components of heavy oil,conditions of water quality and external environment on the basis of comprehensive analysisof the composition and properties of heavy oil thermal recovery sewage; we prepared a metalsalt flocculants Polysilicate-poly silicon zinc sulfate (PSZS) in the lab, and discussed bysingle factor experiment that the concentration of SiO₂, molar ratio of Zn/Si, molar ratio ofB/Si, pH, polymerization time influenced product performance and stability of PSZS,optimum preparation conditions were determined, the structure of the product characterizedby IR spectra, synthetic product was consisitent with the target product; evaluated theflocculation of PSZS on heavy oil thermal recovery sewage in gudong oilfield, when thedosage of PSZS was 400mg/L,the temperature was 70℃,setting time was 0.5h, the sewagetransmittance reached 94.2%, the oil content decreased from 150mg/L to 30mg/L, and 80.0%oil removal rate could be attainted, it indicated that PSZS had good flocculation ability and scertain degree of oil removal capacity; this paper researched high efficient composite waterpurifying agent HQG with strong oil removal capacity and efficient flocculation for heavy oilthermal recovery sewage in gudong oilfield, the formulation of HQG was the ratio ofThg-A2:Thg-9603A:high–purity PAC equal to 2:1:8:4, and optimum applicable conditionswere studied through orthogonal experiment, it was that HQG dosage was 300mg/L,temperature was 80℃, pH was 7, sedimentation time was 20min, oil content in sewagedecreased from 1144.45mg/L to 19.44mg/L, removal rate of oil reached 98.3%, the content ofsuspended matter in sewage decreased from 135.6mg/L to 10.2mg/L, removal rate of SS was 92.5%, the sewage transmittance was 94.2%, the water quality became clear; the actionmechanism of purifying agent for heavy oil sewage was discussed, which mainly containedsurfactant destroyed interfacial film and charge neutralization of polynuclear of Zn²⁺ or Al³⁺and adsorption bridging of layered or chain reticular formation in PSZS, synergistic effect ofthese mechanisms contributed to have good purification effectiveness.