Synthesis And Scale Inhibition Performance Of Polyaspartic Acid Derivatives

In the process of oil and gas exploitation,formation and pipes were blocked by scaling,resulting in serious economic loss,the most effective method to improve economic benefits is using scale inhibitor to inhibit scaling.PASP as a representative "green" scale inhibitor has attracted intensive interest since it has nontoxicity and good biodegradability,In addition,PASP molecule contains carboxylic group with good chelating ability and dispersability,Nevertheless,as it only contains carboxylic group,the comprehensive scale inhibition performance of PASP is poor,which limits its use?In order to improve its comprehensive performance,in this article,we choosed 3-Amino-4-hydroxybenzenesulfonic acid,2-amino-2-(hydroxymethyl)-3-propanediol,o-cmc to modified PSI.sulfonic group?hydroxyl,three hydroxyl,carboxyl?hydroxyl was introduced into the molecular structure of PASP?Through the single factor experiment and orthogonal experiment to get the best synthetic conditions for PSI is MA:NH3H2O=1:1.4,polymerization temperature is 160?,polymerization time is 5h,the PSI production rate is 98.4%.Set scale inhibition ability of barium sulfate scale as index.the best synthetic conditions for PASP/3A4HBSA is PSI:3A4HBSA=1:0.9,reaction temperature is 80?,reaction time is 4h,reaction pH is 12,at this condition the scale inhibition rate is 97.4%;the best synthetic conditions for PASP/TRIS is PSI:TRIS=1:1,reaction temperature is 60?,reaction time is 5h,reaction pH is 11,at this condition the scale inhibition rate is 96.9%;the best synthetic conditions for PASP/O-CMC is PSI:O-CMC=1:0.8,reaction temperature is 70?,reaction time is 6h,reaction pH is 12,at this condition the scale inhibition rate is 98.2%;the best synthetic conditions for PASP/3A4HBSA/TRIS is PSI:3A4HBSA:TRIS=1:0.4:0.6,reaction temperature is 80?,reaction time is 4h,reaction pH is 10,at this condition the scale inhibition rate is 99.2%;The synthesized graft copolymer was characterized by FTIR and 1H NMR.Which proved that the characteristic groups and structure of PSI?PASP/3A4HBSA?PASP/O-CMC?PASP/3A4HBSA/TRIS?PASP/TRIS are in conform with the design.Study the performance of synthetic product,the influence factors of the scale inhibitor concentration,Ba2+(Ca2+)concentration,temperature,time,and pH on the scale inhibition performance for BaSO4 and CaCO3 were investigated.Compared with PASP.The scale inhibition rate and corrosion inhibition have been improved because of the introduction of sulfonic group?carboxyl and hydroxyl groups.Under the same conditions,the order of scale inhibition performance for BaSO4 are PASP/TRIS/3A4HBSA>PASP/O-CMC>PASP/3A4HBSA>PASP/TRIS>PASP,the order of scale inhibition performance for CaCO3 are PASP/TRIS/3A4HBSA>PASP/O-CMC>PASP/TRIS>PASP/3A4HBSA>PASP.The scale inhibition mechanism of the scale inhibitor was analyzed by means of environmental scanning electron microscopy(SEM)?X-ray diffraction(XRD)?Electrical conductivity measurement techniques and the dispersion capacity for BaSO4 and CaCO3.it was found that the mechanism of the inhibitor includes lattice distortion of BaSO4(CaCO3),adsorption dispersion,double layer interaction and complexation of the scale inhibitor and Ba2+(Ca2+).