Synthesis And Performance Study Of MA/AMPS/APEG Scale Inhibitor

The addition of scale inhibitors is one of the main ways the most economical measure to reduce scaling in oil and gas field piping systems or industrial cooling water circulation systems.Researchers have developed a variety of scale inhibitors for high-ionic water in pipelines,such as polysulfonic acid scale inhibitors,polycarboxylic acid scale inhibitors,natural polymer scale inhibitors,or modified natural polymer scale inhibitors and so on,but they all have some drawbacks,cannot effectively solve the problem of the scale deposition under high-ionic concentration conditions.Therefore,there is an urgent need to develop an efficient,environmentally friendly scale inhibitor to meet the needs of oil and gas field piping systems.In this work,according to the effect of scale inhibitors,three functional monomers of maleic anhydride(MA),2-acrylamido-2-methylpropanesulfonic acid(AMPS)and allyl alcohol polyoxyethylene ether(APEG-1000)were used to synthesize a new scale inhibitor.The single-factor experiment was used to optimize the optimal synthesis conditions:the initiator dosage was 3.5%and the monomer molar ratio was n(MA):n(AMPS):n(APEG)=2:1:0.002,the reaction time is 6h,the reaction temperature is 85?,the total mass concentration of the monomers is 20%,and the pH of the solution after reacting is adjusted to pH=7.The crude polymer sample was synthesized under optimal conditions,firstly,using ethanol to purify,and then dissolved in deionized water,and then added with ethanol,repeated three times.The scale inhibitor sample was precipitated,dried,and crushed,obtained a light yellow solid.Fourier transform infrared spectrometer and 1H-NMR were used to characterize the molecular structure.The results showed that the synthesized sample was consistent with the target product structure.The molecular weight of the polymer was measured by GPC.The results showed that the polymer was oligomeric polymer,Mw=3145,Mn=9243,and the distribution was broad,meeting the design of molecular weight.In addition,allyl alcohol polyoxyethylene ethers(APEG-700,APEG-2400)with different ether chain lengths are used to synthesize polymer scale inhibitors MAA-700 and MAA-2400.The inhibition performance of scale inhibitors MAA,MAA-700,MAA-1000 and MAA-2400 at different dosages,different calcium ion concentrations and different time points were evaluated by static experiments.Inhibition performance of MAAs at different dosages:MAA-1000>MAA-2400>MAA-700>MAA,at the dosage of 20mg/L?40mg/L.60mg/L?150mg/L,MAA-1000>MAA-700>MAA>MAA-2400.In the solution with different calcium ion concentration,with the increase of calcium ion concentration,the scaling inhibition performance of MAA,MAA-700,MAA-1000,MAA-2400 will gradually decrease;and in the same calcium ion concentration solution,inhibition performance is MAA-1000>MAA-700>MAA>MAA-2400.What's more with the increase of the same anti-scaling agent,with the increase of time,the concentration of calcium ions added with MAA-1000 in the solution is the highest,and the inhibition efficiency is the best.In addition,the solution property with MAA-1000 maintaining was the best over time.In order to explore the path and mechanism of scale inhibitor.Using scanning electron microscopy(SEM)to observe the change of crystal morphology and X-ray diffraction to analysis(XRD)the change of crystal lattice.As a result,it found the scale inhibitor can disrupt the growth order of calcium carbonate crystal or calcium sulfate,impede the growth rate of the horizontal or vertical direction.UV-vis spectroscopy characterization to discussed the working path of scale inhibitor,it found the maximum absorption peak occur 'red-shift' phenomenon,demonstrated the chealte ability of scale inhibitor.Turbidity analysis shows that ether chains have the ability to disperse microcrystals,similarly,the ether chains of suitable lengths will perform better.The delay time of the precipitation showed that the delayed efficiency of the addition MAA-1000 was better,indicating that calcium carbonate can be effectively inhibited from depositing in the solution as precipitate-like adherent to the bottle body.Subsequently,the sheet-like floats can be easily crushed and separated and the bottle washed away directly by water.