Efficient Viscosity Reduction of Polyacrylamide-Containing Wastewater Through Nonequilibrium Plasma Treatment

Polyacrylamide (HPAM) is the most commonly used polymer in polymer flooding technology, which can effectively improve oilfield recovery efficiency. But simultaneously, a large amount of wastewater will be generated. HPAM can make oil production wastewater highly emulsifying and viscous, increasing the difficulty of treating oil production wastewater. Therefore, finding a method to treat polyacrylamide-containing wastewater quickly and efficiently is necessary. This article designs a nonequilibrium plasma flow reactor. We used this equipment to treat partially hydrolyzed HPAM solution and studied the effects of discharge gas, discharge voltage, discharge time, and solution concentration on the viscosity reduction of HPAM solution. The experimental results show that the viscosity reduction effect of different discharge gases ranges from high to low for air, oxygen, nitrogen, and argon. The viscosity of the polymer containing wastewater will reduce by 99.87% when the discharge gas is air, the discharge voltage is 50 kV, the discharge time is 6 s, and the initial concentration of the solution is 0.5 g/L. At the same time, we measured the changes of the main related substances in the solution before and after the treatment and further analyzed the mechanism of the decrease in solution viscosity. The research results of this article indicate that nonequilibrium plasma treatment is a promising alternative method for treating oilfield wastewater containing HPAM.