Research On The Electric Dehydration Characters Under Different Electric Field Forms And Non-uniform Coefficients

With the depletion of onshore crude oil resources,the amount of offshore crude oil production has increased year by year,the moisture content of crude oil recovery is increasing gradually.The addition of alkali,surfactant and polymer in the three oil recovery techniques has further enhanced the stability of the extraction liquid,reduced the efficiency of dehydration,reduced the stability of electric field,and increased the difficulty of electric dehydration.In order to improve the efficiency of electric dehydration and the stability of dehydration,the article carried out the electric dehydration experiments under different electric field forms and non-uniform coefficients.In order to study the electric dehydration characters of emulsion under different electric field forms,the researches carried out the experiments under DC electric field,high frequency AC pulse electric field,and superposed electric field.The results show that DC electric field is more suitable for dealing with low moisture content emulsion for deep dehydration,high frequency AC electric field is more suitable for high moisture content emulsion,but not for deep dehydration.In order to increase the dehydration efficiency under pulse electric field,we can properly increase the frequency and decrease the duty ratio when the electric field is high,and decrease the frequency and increase the duty ratio when electric field is low;dipole coalescence,vibration coalescence and electrophoresis coalescence all exist,the droplets vibrate when they swim,which increase the coalescence opportunity,be good for dissipation of water chain,and make the electric dehydration more stable.The superposed electric field has the advantages of two type electric fields,it can widen the range of emulsion dealt and increase the electric dehydration stability and efficiency.In order to study the electric dehydration characters of emulsion under different electric field distribution,the researches carried out the experiments under plate electrodes,cylindrical electrodes,and different radius cylindrical electrodes.The results show that the uniform electric field don’t have deep dehydration ability,it is more suitable for low moisture content emulsion;droplets can coalesce by dielectrophoresis force under non-uniform electric field,so it has deep dehydration ability;the electric field is higher on the top and the electric field is lower on the bottom in the structure of different radius cylindrical electrodes,which is more suitable for the droplets distribution that the moisture content is higher,water droplets radius is bigger,and the electric dispersion electric field is higher on the top of the dehydrator.This kind of electric field distribution is better for increasing dehydration efficiency.