Preparation And Performance Evaluation Of Flotation Agents Based On Turbulent Flow

At present,most of the offshore oilfield oily water treatment needs to be reinjected to the formation to achieve the purpose of increasing production and emission reduction,so the sewage treatment effect and treatment capacity are higher.However,due to the limited space of offshore platforms,most of the sewage treatment facilities are installed on ships around the platform.Under the influence of the large output of oily sewage,the small space of treatment equipment and the large sea wind and wave,the sewage flows in the turbulent state,which increases the difficulty for the treatment of oil particles and suspended particulate matter.In the treatment process of impeller air floatation,it is necessary to add supporting flotation agent to improve the treatment rate,but at present there is no finished product in our country,most of them are imported from abroad,and the price is expensive and the supply is poor.According to previous research,impeller flotation agent is mainly composed of polymer and surfactant.Among them,the polymer has the very strong flocculation ability and increases the oil particle diameter,can make the colloid particle demulsifying stability in the oily waste water,is advantageous to improve the oily water treatment efficiency;Surfactant can change the surface wettability of suspended particulate matter in water,enhance the adhesion ability of bubbles to floc,and the surfactant should form a strong and stable foam layer in water.In order to effectively prevent the phenomenon of flocs with gas down.Based on the analysis of the action mechanism of the flotation agent for impeller air flotation,a kind of emulsion flotation agent was prepared under turbulent conditions.The synthesis of cationic polymers with both a certain degree of cation and a suitable molecular weight is the key to the successful preparation of available flotation agents in turbulent state.Polymers with different molecular weights were prepared by adjusting monomer ratio(DMC:AM)and fixing monomer ratio by changing monomer mass fraction and adding amount of crosslinker and chain transfer agent.A series of synthetic polymers were used to evaluate the floatation treatment of oily wastewater.The results showed that the treatment effect of oily wastewater was the best when the cationic degree of polymer was about 20%and the molecular weight was about 1.6 million.However,although cationic polymer can improve the efficiency of air flotation treatment to a certain extent,due to the weak ability of floc to carry bubbles and the failure to form a stable foam layer on the surface of sewage,the transmittance of the treated wastewater is still not high.Therefore,the polymer with appropriate molecular weight,cationic degree and calcium stearate,which can change the wettability of the floc surface,can improve the hydrophobicity of the floc and the foaming AES.Preparation of emulsion type flotation agent.However,the stability of the emulsion has a great effect on the product performance and the practical application effect,and the stability of the emulsion is improved by adding ethyl acrylate and adjusting the compound surfactant formula to the oil phase.The self-made emulsion flotation agent was evaluated by observing the floc production during air flotation and measuring the transmittance of oily water simulated in laboratory before and after treatment.It was found that the self-made emulsion flotation agent had better treatment effect on simulated oily wastewater in laboratory under different turbulence degree,pH value,salt content and so on.When the dosage of flotation agent is 40 mg/L,the transmittance of oily wastewater can be increased from 1.4%to 90.3%.The self-made emulsion flotation agent has the characteristics of making colloid demulsification stable,changing the surface wettability of particulate matter and forming stable foam layer on the water surface,and can effectively solve the problem of poor air flotation treatment efficiency of oily wastewater in oil field under turbulent state.It also provides a theoretical basis for the further study of relevant flotation agents in the future.