Preparation Of A New Kind Of Poly (MA-AA-AMD) Scale Inhibitor Containing The Phosphonyl Group And Its Application Research

The scale effect on the industrial circulating coolin~water has always been a problem for many industries,e.g.,petroleum refining,chemical engineering,and electric power etc.The scale inhibitors now have been used in the circulating cooling water to smooth away the scale effect.The increasing stringent limits for the cooling water and discharge make it necessary to develop the high·-performance green scale inhibitors. A novel scale inhibitor,denoted as PMAA,was prepared by solution polymerization with monomers.i.e.,maleic anhydride(MA),acrylic acid(AA)and acrylamide derivative containing the phosphonyl group(AMD).The optimum preparation conditions were obtained by the orthogonal and single—factor experiments.The PMAA with the excellent scale inhibition performances could be obtained under the optimum preparation conditions,i.e.,n(MA):n(AM)。4.2:1,n(MA):n(AA)。2.0:1,m(HCHO):m(AM)=4.7:1,o)(H202):10.5%,m(PCI3):m(HCH0)。1.5:1,96。C of the reaction temperature and 3.0 h of the reaction time.The PMAA prepared under the condition shows great performances,i.e.the percent of monomer conversion is 98.76%,the scale inhibition rate for CaC03 is 9 1.6 1%,for CaS04 is 83.08%,for Ca3(P04)2 is 90.70%,the molecular weight is 5547.The IR spectrum analyses indicated that the PMAA contained such functional groups as carboxyl group,tertiary amido group and phosphonyl groups etc. The application research results on the PMAA are summarized as follows:(1)The crystal growth of the CaC03 and CaS04 is disturbed by the addition of PMAA.Then the external shapes of the crystals change.And the crystals'volume decreases and their shapes deform.As a result,the scale is loose and can be removed easily.(2)The PMAA can achieve high scale inhibition efficiency of CaC03 with low dosage.Moreover,PMAA Can be used under the conditions of high temperature,high pH value and high concentrates of Ca2'.It can act as a high—performance scale inhibitor at a high temperature for a relatively long time.(3)The performance of PMAA is influenced more greatly by the concentration of Ca2+ in the CaC03 aqueous solution. However,for the other factors,e.g.,temperature,time an.d solution pH showed less influence.(4)For the Ca3(P04)2 scale,PMAA can be applied in a wide range ofconcentrations of Ca2+,even in a concentrated solution,and the inhibitionperformances almost remain constant under various temperature,time and pHconditions.(5)Compared with other popular commercial scale inhibitors,PMAA hasmany better scale inhibition performances.(6)PMAA shows an excellent di~persi-bility for the Fe203,especially at the low concentrations.Furthermore,it also can be used under the critic conditions of high pH and high concentrations of Fe".(7)PMAA maintains excellent performance of scale inhibition in the concentratedsolutions of MgC03.And it is also adaptable tO a high pH circumstance.(8)In theneutral or alkali solutions of the scales,PMAA also has the excellent efficiency for the corrosion inhibition.Moreover.it also acts well in the concentrated solutions. Consequently,the exploitation of PMAA will show a wide application prospectin the circulating cooling water field in industries.