Scale Inhibition Effect Research Articles

Effect of electric field and Mg2+ doping on calcium carbonate scaling shown in experiments and first principle calculations

Abstract The effect of an applied electric field and Mg2+ doping on the formation of calcium carbonate scale in circulating cooling water was investigated by using a home-made experimental device, which can simulate the formation of scale in a local power plant. The results show that high-voltage electrostatic fields and magnesium ions can inhibit scale growth in circulating cooling water. When the magnesium ion concentration is 4 mmol/L, the scale inhibition effect is the best under the action of the electric field (6 kV), and its scale inhibition rate can reach 44.56%. Meanwhile, some phenomena are explained and confirmed by the results of first principle calculations. The calculated shear modulus of aragonite is greater than that of calcite. This might explain why aragonite adheres more easily to the heat exchange surface. This is in good agreement with experimental results. Calcite has better anti-scaling properties than aragonite. The crystal structure after physical water treatment is blunt, and the untreated crystal structure is sharp.

Synthesis and property study of ter-copolymer P(MA-AMPS-HPA) scale inhibitor

The purpose of this study is to construct a scale inhibitor with high efficiency for calcium carbonate scale, calcium sulfate scale and barium sulfate scale. For this purpose, the ter-copolymer P(MA-AMPS-HPA) was synthesized by aqueous solution polymerization method using maleic anhydride (MA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and hydroxypropyl acrylate (HPA) as raw materials and ammonium persulfate as initiator. The optimum synthesis conditions of ter-copolymer P(MA-AMPS-HPA) were discussed by single factor method. The relationship between the scale inhibition performance and the molecular weight of ter-copolymer P(MA-AMPS-HPA) was discussed. The structure of ter-copolymer P(MA-AMPS-HPA) was characterized by FTIR. TGA showed that ter-copolymer P(MA-AMPS-HPA) had excellent thermal stability. The scale inhibition mechanism for different scale samples was preliminarily investigated by SEM and EDS analysis. The scale inhibition performance of ter-copolymer P(MA-AMPS-HPA) was evaluated by changing the concentration of ter-copolymer P(MA-AMPS-HPA) in aqueous solution, the experimental temperature and pH of the solution. It was found from the tests results that the scale inhibition rate of ter-copolymer P(MA-AMPS-HPA) for calcium carbonate scale, calcium sulfate scale and barium sulfate scale reached 100%, 98% and 72%, respectively. By comparison, the synthesized ter-polymer had better scale inhibition effect than the bicopolymer.

Evaluation of Scale and Corrosion Inhibition of Modified Polyaspartic Acid

AbstractAmino acid modified polyaspartic acids were evaluated as calcium‐scale inhibitors. Feasibility of scale inhibition experiments was analyzed by molecular dynamics simulation and Gaussian optimization, and the scale inhibition mechanism was theoretically analyzed. Scale inhibition performance was studied by scanning electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, static scale inhibition experiments, and electrochemical performance testing, which provided an experimental basis for the molecular dynamics simulation. The experimental results showed that Arg‐SA‐PASP has better scale inhibition and corrosion inhibition performance than His‐SA‐PASP. The scale inhibition effect increased with increasing concentration. Electrochemical tests indicated that Arg‐SA‐PASP is an excellent scale and corrosion inhibitor.

Computational Simulation about the Impact of High Voltage Electrostatic Field on Crystallization of Calcium Carbonate Aqueous Solution

Computational simulation method was used in two models of calcium carbonate aqueous solution to explore the mechanism of anti-scaling under electrostatic field on the molecular level. The binding energy between the surface and ions indicated that the surface (104) was more favorable for the growth of the new crystal, while it was much easier to decompose under field strength 1300 V/m. The diffusion coefficients of Ca2+ and CO32- revealed that the chemical reaction of Ca2+ and CO32- ions in Model-II was much difficult to form calcium carbonate crystal under electrostatic field. The hydration degree of Ca2+ with O atoms from water molecules showed that the electric field could enhance the hydration degree of Ca2+ under certain field length, hence preventing the chemical reaction with CO32- to produce crystal. In short, the scale inhibition effect under electrostatic field in Model-II was much better.

Scale inhibition effect of Hylocereus undatus solution on calcium carbonate formation

In this paper, the inhibiting properties of an aqueous solution containing Hylocereus undatus towards CaCO3 formation were studied by using fast controlled precipitation and chronoamperometric methods, in order to study the calcium carbonate formation in solution and on a metallic surface, respectively. As a purpose of comparison, the antiscaling properties of citric acid were studied in the same experimental conditions. The results obtained by fast controlled precipitation method showed that Hylocereus undatus solution was more efficient than citric acid to inhibit CaCO3 formation in solution (optimal concentrations of 20 and 24 mg L−1, respectively). By using the chronoamperometric method, a concentration of citric acid at 160 mg L−1 was required to totally prevent the precipitation of CaCO3 whereas it was 180 mg L−1 for Hylocereus undatus solution. The morphology analysis by scanning electronic microscopy and X-ray diffraction revealed that vaterite was favored in the presence of Hylocereus undatus solution, whereas a mixture of calcite and vaterite was obtained with citric acid.

Effect of alternating electromagnetic field and ultrasonic on CaCO3 scale inhibitive performance of EDTMPS

Abstract In this study, the influence of Ethylene Diamine Tetra Methylene Phosphonic Acid Sodium (EDTMPS) on the precipitation of CaCO3 under alternating electromagnetic field (AEMF) and ultrasonic (US) treatment were investigated. The variations of pH value and the Ca2+ concentration of hard water solution were monitored, and the crystalline phase and morphology of precipitated CaCO3 crystals were characterized by XRD and SEM. The experimental results show that the presence of EDTMPS can inhibit the precipitation of CaCO3. In the 30 mmol/L Ca(HCO3)2 solution, when the EDTMPS concentration were 2.5 mg/L, 5 mg/L, 7.5 mg/L and 10 mg/L, the antiscale efficiencies were 34.08%, 63.67%, 70.79% and 71.16%, respectively. Thus, the antiscale efficiency correlates positively with EDTMPS concentration. The presence of EDTMPS can also inhibit the CaCO3 conversion from vaterite to calcite. The AEMF has the effect of hindering the precipitation of CaCO3 and inducing CaCO3 precipitates as vaterite crystals. Furthermore, it is significant that the AEMF can effectively improve the scale inhibition effect of EDTMPS, which means the EDTMPS used in combination with AEMF could be a good method to improve the scale inhibition. On the other hand, the US promotes the CaCO3 precipitation as calcite crystals with smaller size. Under the action of US, the EDTMPS loses its inhibition effect after a certain period of time, possibly due to the US destroys the connection between Ca and EDTMP and free the Ca2+ in the solution.

Effect of Carbon Nanoparticles on the Crystallization of Calcium Carbonate in Aqueous Solution.

Nanofluids have great application prospects in industrial heat exchange systems because they can significantly improve the heat and mass transfer efficiency. However, the presence of nanoparticles in the fluid might also affect the formation and attachment of inorganic scales, such as calcium carbonate, on the heat exchange surface. The effects of carbon nanoparticles on the crystallization of calcium carbonate in aqueous solution were studied by the scale inhibition test, solution analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The results showed that carbon nanoparticles had an excellent surface scale inhibition performance for calcium carbonate, which could effectively prevent the adhesion of scale on the heat exchange surface. The carbon nanoparticles did not affect the solubility of calcium carbonate in water, but changed the crystal form of the precipitated calcium carbonate, making it difficult to adsorb on the heat exchange surface and achieving a surface scale inhibition effect. Carbon nanofluids effectively inhibit the adhesion of calcium carbonate to heat exchange surfaces.

Synthesis of MA/AA/MA-β-CD/SHP Quadripolymer and Its Performance Evaluation as Scale Inhibitor

A new scale inhibitor MA/AA/MA-β-CD/SHP was prepared from maleic anhydride, acrylic acid, sodium hypophosphite, and MA-β-CD via the method of free radical polymerization in aqueous solution. The MA-β-CD was obtained through the modification of β-cyclodextrin (β-CD) with maleic anhydride (MA). Results of performance evaluation showed that the synthesized copolymer has excellent scale inhibition effect for the calcium scale, and the resistance rate of silicon scale up to 79.81%. The structure, thermal property, and morphology of the copolymer were characterized by FTIR, TGA, and SEM. From crystallization data and morphology of the scale crystals it was found that the copolymer scale inhibitor can make the crystal lattice distortion, and has a good dispersing ability after addition of the scale inhibitor.

Evaluation of the structural morphology of starch-graft-poly(acrylic acid) on its scale-inhibition efficiency

The development of phosphorus-free and biodegradable scale inhibitors has been paid considerable attention. Two series of starch-graft-poly(acrylic acid) (St-g-PAA) samples with different grafting ratios and grafted-chain distributions, that is, the number and length of grafted PAA chains on the starch backbone, were designed and prepared in this study. Fourier transform infrared and 1H nuclear magnetic resonance spectra were used to further characterize the molecular structures of the St-g-PAAs. In addition to dose, the effects of the structural morphologies of St-g-PAA, namely, grafting ratio and grafted-chain distribution, on the scale-inhibition performance against calcium carbonate were investigated systematically. Structural morphology significantly influenced the scale-inhibition performance of St-g-PAA. St-g-PAA with relatively low grafting ratio (≤97%) displayed better scale-inhibition effect than samples with similar grafted-chain distributions. Meanwhile, under the similar grafting ratios, samples with higher number of branched chains with shorter grafted chains displayed better antiscaling performance. Thus, higher scale-inhibition rate and lower corresponding optimal dose were obtained. Different scale-inhibition mechanisms were involved in the effects of the structural morphology. These mechanisms were investigated in detail from the molecular levels using scanning electron microscopy and X-ray diffraction.

Study on Alkaline Flooding System with Antiscaling Effect

For scaling problem in the alkaline flooding, the alkali with anti scaling effect was researched. The results show that scale inhibition effect of PAPEMP alkaline system (containing polyamino polyether methylene phosphonae, NaOH, NaBO2) is better than PASP alkaline system (containing sodium of polyaspartic acid, NaOH, NaBO2), When the concentration of the PAPEMP alkaline system is larger than 4%, it could tolerate the solution with calcium ion concentration of 500mg/L without scaling; both NaBO2 and PAPEMP alkaline system have good displacement efficiency. During the displacement process, a large differential pressure response appears when alkali concentration is high, and the incremental oil recovery increases with the increase of alkaline concentration. Microscopic mechanisms show that the alkaline solution penetrates into the crude oil and water drops are formed inside the oil phase, subsequently, to turn into the W/O emulsion, which could block the water channel and inhibit the viscous fingering, leading to the improvement of sweep efficiency.

Preparation of fluorescent polyaspartic acid and evaluation of its scale inhibition for CaCO3 and CaSO4

Polysuccinimide was synthesized from maleic anhydride and urea. A polyaspartic acid derivative (PASP‐Try‐SEA) was synthesized from the polysuccinimide with 2‐aminoethanesulfonic acid and tryptophan. The products were characterized by UV, FTIR,1H NMR, TGA and PL, respectively. The results showed that the fluorescent chromophore‐indolyl groups were successfully incorporated into PASP. The relationship between the fluorescence intensity and the concentration of fluorescent polyaspartic acid (FPASP) is linear with the excitation wavelength of 366 nm and 422 nm. FPASP also showed excellent scale inhibition properties with a scale inhibition rate of 78% achieved for CaCO3 with a dosage of 9 mg/L and a significantly enhanced scale inhibition effect for CaSO4, achieving an inhibition rate of 98%, which were determined using the static scale inhibition method. When FPASP was added to the solution, CaCO3 and CaSO4 deposits showed flower patterns with floppy accumulation by scanning electron microscopy. Copyright © 2016 John Wiley & Sons, Ltd.

Dynamic synergistic scale inhibition performance of IA/SAS/SHP copolymer with magnetic field and electrostatic field

An IA/SAS/SHP copolymer was synthesized by itaconic acid (IA), sodium allysulfonate (SAS) and sodium hypophosphite (SHP). This IA/SAS/SHP copolymer was characterized by Fourier transform infrared spectrometry (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The dynamic synergistic scale inhibition performance of the IA/SAS/SHP copolymer against CaCO3 in the presence of magnetic field and electrostatic field was studied using dynamic scale inhibition experiments. The results showed that there existed synergistic scale inhibition effect of IA/SAS/SHP copolymer against CaCO3 with magnetic field and electrostatic field. Comparing with single IA/SAS/SHP copolymer, the synergistic scale inhibition efficiency of IA/SAS/SHP copolymer against CaCO3 increased by 9.76% in the presence of magnetic field and 16.65% in the presence of electrostatic field. The scale inhibition efficiency of IA/SAS/SHP copolymer against CaCO3 in the presence of the magnetic field and electrostatic field as high as 100% was reached when IA/SAS/SHP copolymer concentration was 0.5mg/L, pH was 7.3, and temperature was 40°C. Morphology and crystal phase of calcium carbonate were characterized by SEM and XRD.

Effect of six kinds of scale inhibitors on calcium carbonate precipitation in high salinity wastewater at high temperatures

Precipitation of calcium carbonate (CaCO3) scale on heat transfer surfaces is a serious and expensive problem widely occurring in numerous industrial processes. In this study, we compared the scale inhibition effect of six kinds of commercial scale inhibitors and screened out the best one (scale inhibitor SQ-1211) to investigate its scale inhibition performance in highly saline conditions at high temperature through static scale inhibition tests. The influences of scale inhibitor dosage, temperature, heating time and pH on the inhibition efficiency of the optimal scale inhibitor were investigated. The morphologies and crystal structures of the precipitates were characterized by Scanning Electron Microscopy and X-ray Diffraction analysis. Results showed that the scale inhibition efficiency of the optimal scale inhibitor decreased with the increase of the reaction temperature. When the concentration of Ca2+ was 1600mg/L, the scale inhibition rate could reach 90.7% at 80°C at pH8. The optimal scale inhibitor could effectively retard scaling at high temperature. In the presence of the optimal scale inhibitor, the main crystal structure of CaCO3 changed from calcite to aragonite.

Electromagnetic Field Acting on the Scale Inhibition Experiment and Mechanism on Circulating Cooling Water of Power Plant

The scale-inhibition effect of electromagnetic field was tested on circulating cooling water of power plant, and then the scale sample was analyzed by SEM and XRD. The results showed that, under optimum scale-inhibition conditions, aragonite content increased and calcite content decreased, and scale-inhibition rate was up to 78.2%; under the poorest conditions, both aragonite and calcite crystals existed, and the scale-inhibition rate was-201.0%; after treating with electromagnetic field, size of both calcite and aragonite particles decreased, making them more easily flown away and thus showing better overall scale-inhibition effect; when energy provided by the electromagnetic field was more than the decrease in free energy of the system, extra energy turns the calcite CaCO3 into other forms of metastable crystalline phases, then content of different crystalline phases is changed in favor of scale inhibition.

Dynamic Simulation Test on Scale Inhibition of Secondary Effluent of Sewage Treatment Plant Directly Reused in Power Plant Circulating Cooling Water System

Secondary effluent of sewage treatment plant directly reused in power plant circulating cooling water system was the main cause of scale inhibition in the system.Facing this serious scaling problem,static scale inhibition experiment was carried out to filter out the efficient compound formulation.Corrosion inhibition performance by rotary coupon experiment was studied.Scale and corrosion inhibition effect under the field condition by homemade dynamic simulation experiment and the environment toxicity were tested. The result showed that this water treatment agent gain the high scale and corrosion inhibition effect, with low phosphorus,non-toxic,friendly to environment.

Dynamic Laboratory Research on Synergistic Scale Inhibition Effect of Composite Scale Inhibitor and Efficient Electromagnetic Anti-Scaling Instrument

This study studied the synergistic anti-scaling performance of composite scale inhibitor and efficient electromagnetic anti-scaling instrument. And experiments were conducted to investigate the anti-scaling performance of composite scale inhibitor and anti-scaling performance and mechanism of efficient electromagnetic anti-scaling instrument, respectively. The crystallization of CaCO₃ was characterized by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The experimental results showed that the highest anti-scaling rate of composite scale inhibitor (1#) was 80.68% and highest anti-scaling rate of composite scale inhibitor (2#) was 76.53%, average anti-scaling rate of efficient electromagnetic anti-scaling instrument was 51.46%. Efficient electromagnetic anti-scaling instrument promoted CaCO₃ crystallization process and promoted calcite into aragonite. When efficient electromagnetic anti-scaling instrument worked with composite scale inhibitor, synergistic anti-scaling rate of composite scale inhibitor (1#) had a 15% higher than composite scale inhibitor (1#) and synergistic anti-scaling rate of composite scale inhibitor (2#) had a 20% higher than composite scale inhibitor (2#).

Scale Inhibition of the ESA / AMPS Copolymer with Magnetic Field or Electrostatic Field

The scale inhibition of the ESA/AMPS copolymer under the magnetic field or electrostatic field was researched by using static scale inhibition experiments. The result showed that there were synergistic scale inhibition effect between magnetic field and ESA/AMPS copolymer, and the electrostatic field and ESA/AMPS copolymer also had synergistic scale inhibition. The scale inhibition rate of both magnetic field and ESA/AMPS copolymer on CaCO3 increased by 12% as compared with that of ESA/AMPS copolymer alone. And the synergistic scale inhibition rate on Ca3(PO4)2 increased by 42.4% .The increased scale inhibition rate of the ESA / AMPS copolymer on CaCO3 with electrostatic field was 19%,and the scale inhibition rate on Ca3(PO4)2 could increace 73.3%.

Application of 1-hydroxyethylidene-1, 1-diphosphonic acid in boiler water for industrial boilers

The primary method used for boiler water treatment is the addition of chemicals to industrial boilers to prevent corrosion and scaling. The static scale inhibition method was used to evaluate the scale inhibition performance of 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP). Autoclave static experiments were used to study the corrosion inhibition properties of the main material for industrial boilers (20# carbon steel) with an HEDP additive in the industrial boiler water medium. The electrochemical behavior of HEDP on carbon steel corrosion control was investigated using electrochemical impedance spectroscopy and Tafel polarization techniques. Experimental results indicate that HEDP can have a good scale inhibition effect when added at a quantity of 5 to 7 mg/L at a test temperature of not more than 100 °C. To achieve a high scale inhibition rate, the HEDP dosage must be increased when the test temperature exceeds 100 °C. Electrochemical and autoclave static experimental results suggest that HEDP has a good corrosion inhibition effect on 20# carbon steel at a concentration of 25 mg/L. HEDP is an excellent water treatment agent.

Synthesis and Scale Inhibition of a Polyether-typed Non-phosphorus Copolymer

A new type of polyether copolymer—allyloxy polyether carboxylic acid sodium/acrylic acid(APEX/AA) was synthesized using water as solvent and APEX and AA as monomers.Polymer APEX/AA was characterized by infrared spectroscopy,thermogravimetric analysis and gel permeation chromatography.The dosage of APEX/AA,calcium ion concentration in solution,pH and temperature were evaluated on phosphate calcium scale inhibition efficiency through static method.The results show that the polymer APEX/AA has good thermal stability at temperature above 350 ℃,and its relative molecular mass distribution is controllable(PDI=1.41~1.88).The phosphate calcium scale inhibition efficiency of APEX/AA reached 100% when a concentration of 6 mg/L aqueous system was used.The results show that APEX/AA is suitable for water with a high calcium ion concentration(200~2000 mg/L),high pH(7.5~11.0) and high temperature(75~95 ℃).The scale inhibition effect of APEX/AA is superior to that of commercial calcium phosphate scale inhibitors such as 1-hydroxyethylidine-1,1-diphosphonic acid(HEDP),hydroxypropyl acrylate/acrylic acid(T-225) and 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA),indicating that APEX/AA is an excellent non-phosphorus phosphate calcium scale inhibitor in the industrial circulating water systems.

Study on scale inhibition performances and interaction mechanism of modified collagen

The modified collagens with rich carboxyls were prepared by chemically modifying collagen, which was firstly extracted by hydrolyzing chrome shavings, using the multi-aldehyde acid compounds (MACs) as the modifiers. Then those modified collagens and the blank collagen were used as scale inhibitors to implement scale inhibition tests. Scanning electron microscope (SEM) and XRD analyses were utilized to characterize morphology and crystal form of calcium carbonate scale. Results showed that the Ca2+ concentration and pH were the main influencing factors within the scale inhibition system, specifically the scale inhibition efficiency would be reduced with the increase of Ca2+ concentration and pH. Both the two types of scale inhibitors were more sensitive to the temperature, i.e., the scale inhibition rates were in a downward trend with augment of the temperature. The crystal form of calcium carbonate could be completely distorted to form a vaterite crystal through the action of modified collagens, thus the scale inhibition effect is achieved.