Study On Synthesis And Properties Of A Copolymer Type Scale Inhibitor

At present, amount of alkali is used in crude oil to enhance oil recovery, so scaling is serious in the pipeline. Therefore inhibitors play an important role in the process of oil extraction, inhibitors are effective to CaCO3,CaSO4,BaSO4 et al, whereas the silicon inhibitors are less. oxiranemethane sulfonic acid sodium salt/acrylamide copolymer has the performance in inhibiting the silica scale wich was synthesized in this paper.Firstly the detection method of silicon content (GB/T16633-1996) was improved, for ascorbic acid solution was used as a reductant in this paper.Silicon content was determined with spectrophotometer when the most suitable wavelength was 810nm, the optimal dosages of hydrochloric acid, ammonium molybdate, oxalic acid and ascorbic acid standard solution were 0.8mL, 1.0mL and double 1.5mL in 50 mL testing solution, respectively. With wich that the standard curve of silicon content (silicon content x/mg, absorbance y/L·(g·cm)^-1) x=(y-0.0258)/8.0079 was obtained. The relationship between silicon content (x₂/ppm) and extinction (x₁/L·(g·cm)^-1) is x2=832.5112×(x₁-0.0258) in solution with 500ppm silicon content.Oxiranemethane sulfonic acid sodium salt/acrylamide copolymer was designed and synthesized. The structure of the product was confirmed by IR. The relationship between its synthetic conditions and the performance of the silica scale inhibitior was explored. The results showed that when at the same addition amount the mol ration of oxiranemethane sulfonic acid sodium salt and acrylamide copolymer was 1:3, the reaction time was 2h, the polymerization temperature was 75℃and the amount of the initiator was 1% of the monomer quality, the performances in inhibiting the silica scale were superior to other conditions in 72h, and the silicon content could maintaine at about 85ppm when the addition amount was 20ppm from 24h to 72h. At the same polymerization condition, the former performance in inhibiting the silica scale and the viscosity of the polymer were increased with the increase of proportion of acrylamide in polymer. When at the same addition amounts the mol ration of oxiranemethane sulfonic acid sodium salt and acrylamide was 1:7, respectively, at the former 6h the performance in inhibiting the silica scale were superior to other conditions. And the silicon could maintaine at 146ppm when the addition amount was 20ppm at 6h, the performance in inhibiting the silica scale was improved.Also the performance of oxiranemethane sulfonic acid sodium salt/acrylamide copolymer in inhibiting the calcium and magnesium scale was detected, only when the mol ration of oxiranemethane sulfonic acid sodium salt and acrylamide was 1:3 and the addition amount was 40ppm, the magnesium scale inhibition rate was 63%, when other conditions the addition amount was 20ppm, 30ppm, 40ppm and 50ppm, respectively. There was no performance in inhibiting the calcium and magnesium scale. Compared with the conventional scale inhibitors, the performance of oxiranemethane sulfonic acid sodium salt/acrylamide copolymer in inhibiting the calcium and magnesium scale was worse and the addition amount was larger. However, compounded it with the conventional scale inhibitors reasonable would have better performance in inhibiting the complex scale.