Influence Of Polyacrylates Pour Point Depressant On Shape Properties Of Wax And Rheological Properties Of Crude Oil

Today the petroleum is becoming more and more important,but as the exploration quantity increasing there are higher wax content and high asphaltene crude oil appear at the oil field.Those crude oils have high solidifying point(SP)and viscosity so the exploration and transportation of them are difficult.Adding pour point depressant(PPD)is a simple and economic way to solve the problem.Octadecyl acrylate-maleic anhydride(OM)and octadecyl acrylate-maleic anhydride-styrene(OMS)were synthesized and the better experimental conditions were determined by orthogonal experiment.Then the alcoholysates,including PPD OMO-22?OMSO-16?OMSO-18?OMSO-22 were synthesized by using OM/OMS and alcohols with different chain lengths.FTIR results confirmed the products were the target molecules.The PPD OM and its alcoholysates OMO-22 were used to deal with Liaohe crude oil and OMS?OMSO-16?OMSO-18?OMSO-22 were used in Jilin crude oil.Then the SP,the shape properties of wax,the rheological properties of crude oil before and after adding PPD were investigated.The results showed that PPD could reduce the SP and yield value effectively and broke down the gel structure of crude oil.The shape of wax turned into spheroid aggregates after PPD were added.The better PPD for Jilin crude oil OMS was selected to evaluate the compound methods.The PPD compounded with EVA or surfactants had better effects than single PPD in some cases.The model oil was used to study the interaction between PPD and components in crude oil and the performance mechanism was also speculated.According to the results,crystalline solids such as paraffin wax and naphthalene were detrimental to the SP depression.The resin and asphaltene could adsorb on the surface of waxes which lead to dispersion of them.PPD with aromatic rings had a better effect in model oil contained resin.The liquid components with lower molecular weight such as toluene,alcohols with short chains acted as thinners for paraffin wax.The long chains components could disperse or solubilize the PPD because of their high surface activity.From the polarized microscopy images it can be seen the wax became spheroid aggregates from sheet-shape.The rheological curves showed that PPD reduced the viscosity of crude oil in non-Newtonian range and improve the fluidity at lower temperature.