Scale Inhibition Rate Research Articles

Synthesis of a copolymer with filter aid, dihydration, and scale inhibition abilities and its application to wet phosphoric acid

A new type of multifunction copolymer PAMA having filter aid, dihydration, and dynamic scale inhibition properties was synthesized using acrylamide (AM) and a homemade polyoxyethylene octylphenol ether acrylic ester (AOP) as the feedstock and persulfate as the initiator in an aqueous solution. The structure of the copolymer was characterized using FTIR and 1H NMR spectroscopy. Scanning electron microscopy and the software Matlab 7.0 were used to investigate the influence of the copolymer on filter aid and scale inhibition. The results indicated that the copolymer consists of AM and AOP. The filtration rates of the phosphogypsum slurry increased 3.8 times compared to the blank group, and the water content of the phosphogypsum cake was reduced by 10.42% with the addition of 10 ppm of PAMA. The dynamic scale inhibition rate of sodium fluorosilicate and potassium fluorosilicate can reach up to 53.5% when the experiment runs continuously for 12 h. The experiments related to mechanism indicate that PAMA has a strong adsorbability and high bridge effect on the phosphogypsum crystals. Concurrently, PAMA can efficiently improve the microstructure of a filter cake and remove the scale layer of sodium fluorosilicate and potassium fluorosilicate adhering to the wall of a stainless steel pipe, which is beneficial for increasing the filter rate, decreasing the moisture content of the filter cake, and preventing scale layer formation on the filter.

Effect of permanent magnetic field on scale inhibition property of circulating water.

Effect of a permanent magnet field on the scale inhibition property of circulating water was investigated. Orthogonal experiments of L16(45) were performed and analyzed using the range analysis method. The operating parameters included magnetic field intensity, initial concentration of Ca2+ and Mg2+, magnetic treatment time, temperature, and flow velocity. Scale inhibition rate, hardness, relative variation in the proportion of free water molecules, electrical conductivity, and relative variation of molecular energy were chosen as the objectives. In addition, the morphology and the composition of CaCO3 and MgCO3 scale were studied by X-ray diffraction analysis. The optimal conditions were initial concentration of 900 mg/L, magnetic field intensity of 0.5 T, temperature of 303 K, time of 54 h and flow velocity of 0.17 m/s. The nuclear magnetic resonance results demonstrated that the number of hydrogen bonds increased between water molecules and hydrated ions. The magnetic field can promote the increase in the number of hydrogen bonds, which can inhibit the formation of calcium and magnesium carbonate precipitation. Moreover, the ratio of calcite, aragonite and vaterite will be changed at different magnetic field intensities, and the aragonite ratio will reach the peak at the optimum conditions.

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.

Inhibition of calcium sulfate scale by poly (citric acid)

Condensation polymerization of citric acid successfully prepared Poly (citric acid). The polymerization product has characterized by FTIR and UV spectroscopy. The polymerization has confirmed to perform well and there are suspended carboxylic groups on the polymer molecules. Inhibition performance of new obtained poly (citric acid) for CaSO4 scale has evaluated by static scale inhibition method. When the dosage of polymer scale inhibitor is 2.5mg/L in initial simulated scaling aqueous solution in which the ion concentrations of Ca2+ and SO42− are both 2040mg/L, the scale inhibition rate exceeds to 90%. When the dosage of polymer scale inhibitor is 25mg/L, the scale inhibition rate is up to 98.8%. All of the results indicate that poly (citric acid) increase the Ca2+ ion concentration in heated simulated scaling water and decrease the deposit of CaSO4 crystals. The CaSO4 crystals collected from simulated scaling water observed by SEM and characterized by FTIR and XRD. The results illustrate that the polymer inhibitor evidently affects the procedure of scale crystal growing. Poly (citric acid) might absorb on the surface of CaSO4 scale crystals and distort the CaSO4 scale crystal polymorphs. Therefore, poly (citric acid) could use as a kind of potential CaSO4 scale inhibitor.

Preparation of scale inhibitor by using the waste of refined 2‐acrylamido‐2‐methylpropane sulfonic acid

Acrylic acid‐2‐acrylamido‐2‐methylpropane sulfonic acid (AA‐AMPS) is a kind of copolymer with good scale and corrosion inhibition performance. Refining of AMPS produces refined residue, which belongs to hazardous waste and must be properly treated and disposed. In this work, the refined residue was reused as the raw material to synthesize scale inhibition copolymer with the addition of AA. The chemical construction and thermal properties of copolymers were confirmed by NMR, FTIR, and thermogravimetry analysis (TGA). To achieve a comprehensive and systematic understanding of copolymers, the inhibition behavior of CaCO3, Ca3 (PO4)2, and CaSO4 were examined through static scale inhibition tests. The capability of ferric oxide dispersion was also determined. The results of structural analysis were consistent with the expected structures. Static experiments were observed that scale inhibition of Ca3 (PO4)2 and CaSO4 was excellent and the scale inhibition rate was close to 100% when the concentration of AA‐AMPS was 30 mg L−1. It was noticed that the performance of copolymers synthesized with AMPS residue appeared nearly no different than when AA‐AMPS was synthesized with normal materials. The results show that the refined AMPS residue could be reused as raw material to prepare scale inhibitor copolymer.Significance: Refined residue of AMPS was used to synthesize scale inhibition copolymer in this work. It would bring serious damage to society and environment if the hazardous waste refined residue cannot be properly treated and disposed. This study shows that the reuse of refined residue could achieve the goals of making use of waste and save the resources. This reuse technology develops a new way to reuse the hazardous waste and it would provide both economical and environmental benefits. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 833–839, 2016

Synthesis of polyaspartic acid derivative and evaluation of its corrosion and scale inhibition performance in seawater utilization

A polyaspartic acid derivative (PASP-SEA-ASP) was synthesized from polysuccinimide with 2-aminoethanesulfonic acid and aspartic acid. PASP-SEA-ASP achieved a better corrosion inhibition rate for A3 carbon steel in seawater compared with polyaspartic acid (49% cf. 45% at the dosage of 100mg/L). The development of a composite inhibitor (a mixture of PASP-SEA-ASP, zinc sulfate, 2-hydroxyphosphonoacetic acid (HPAA) and hexadecylldimethyl (2-sulfite) ethyl ammonium on a mass ratio of 15:3:6:1, respectively) led to a significantly enhanced corrosion inhibition effect, achieving an inhibition rate of 97%. The mass ratio of the composite inhibitor could be adjusted to achieve the desired corrosion inhibition rate for seawater with varying characteristics. PASP-SEA-ASP also showed excellent scale inhibition properties for seawater, with a scale inhibition rate of 100% achieved with a dosage of 14mg/L. This study demonstrated the potential of PASP-SEA-ASP to inhibit both corrosion and scale formation in domestic and industrial utilization of seawater such as cooling systems and thermal desalination processes.

Synthesis of itaconic acid—sodium allysulfonate—sodium hypophosphite copolymer and evaluation of its scale and corrosion inhibition performance

A novel biodegradable multifunctional scale and corrosion inhibitor containing carboxylic acid, sulpfonic acid, and phosphonic acid groups was synthesized from the monomers of itaconic acid (IA), sodium allysulfonate (SAS), and sodium hypophosphite (SHP) by oxidation–reduction initiator system. The optimum synthesis conditions were determined by orthogonal experiments. The performances of scale and corrosion inhibition, dispersion, and biodegradability of the IA/SAS/SHP copolymer were studied. The results showed that the IA/SAS/SHP copolymer has good performances of scale and corrosion inhibition, dispersion performance on ferric oxide, and biodegradability. When the concentration of IA/SAS/SHP copolymer was 20 mg/L, the scale inhibition rate was 95.1%. When the concentration of the IA/SAS/SHP copolymer was 60 mg/L, the corrosion rate was 0.02823 mm/a and the corrosion inhibition rate reaches above 90%. The CaCO3-scale samples and the corrosion testing pieces were observed and analyzed by SEM. The IA/SAS/SHP copolymer could destroy the growth habits of the crystal and lead to crystal distortion.

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.

Green Composite Scale Inhibitor in Central Air Conditioning Cooling Water

With the improvement of living standards, air conditioning becomes the requisite of people’s life; the central air conditioning has become each big building of major appliances[1]. In the whole air conditioning cooling water treatment system, such as scale and sludge which is formed by the metal corrosion phenomenon, will seriously affect the use efficiency of air conditioning. One of the effective solution is adding scale inhibitor to the circulating water. Calcium carbonate deposition method is used to evaluate the scale inhibition rate of PASP, PESA and poly glutamic acid. then evaluate the scale inhibition rate of two compound formula. Results show that PESA with the best scale inhibitor performance, on the basis of its, respectively, compound with PASP and poly glutamic acid. The compound repice can improve the efficiency of scale inhibition. The optimized prescription is that, the PASP is 4mg/L, the PESA is 6mg/L, at this time of scale inhibition efficiency can reach 93.43%.

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.

Synthesis and Properties of Environmentally Friendly Scale and Corrosion Inhibitor

Polyaspartic acid (PASP) and a copolymer (AA) of acrylic acid and acrylicester were synthesized. A ternary composite (PASP-AA-DTPMP) was made from PASP, AA and DTPMP. The performances of ternary composite were studied by using static scale inhibition and weight loss of rotating hung steel slices test. When the concentration of ternary composite was 6mg/L, the scale inhibition rate reached 95% and the corrosion inhibition rate reached 97.9%. The results showed that the ternary composite had good scale and corrosion inhibiton performance and was suitable for high temperature and hardness circulating cooling water system.

Investigation of influence of low phosphorous co-polymer antiscalant on calcium sulfate dihydrate crystal morphologies

Increasing environmental concerns and discharge limitations have imposed additional challenges in industrial cooling water treatment. Increasing research efforts have been directed towards finding economical and environmentally friendly inhibitors. In this study, a novel inhibitor of low phosphorus co-polymer was prepared. The inhibition performance of the novel low phosphorus co-polymer as calcium sulfate dihydrate scale inhibitors, the influence of phosphorus content and viscosity weighted average molecular weight on inhibition were evaluated in simulated cooling water. The results indicate that the optimal preparation conditions of the novel low phosphorus co-polymer for inhibiting calcium sulfate dihydrate were 2.103 of sodium ρ-styrene sulfonate/maleic anhydride ratio, 0.26 of the ratio of hypophosphorous to monomer, and 0.57 of the ratio of hydrogen peroxide to hypophosphorous. The novel low phosphorus co-polymer strongly affected the calcium sulfate dihydrate scale formation, the scale inhibition rate was 94%, and phosphorus content and viscosity weighted average molecular weight also evidently influence the scale inhibition rate to calcium sulfate dehydrate. Scanning electronic microscopy and powder X-ray diffraction investigations reveal that the crystal structure of the calcium sulfate dehydrate is highly modified in the presence of the novel low phosphorus co-polymer.

Development of anti-scale poly(aspartic acid–citric acid) dual polymer systems for water treatment

The formation of calcium sulphate and calcium carbonate scale poses major problems in heat exchangers and water cooling systems, thereby affecting the performance of these types of equipment. In order to inhibit these scale formations, new types of biodegradable water soluble single polymer and dual poly(aspartic acid–citric acid) polymers were developed and tested. The effectiveness of single polymer and four different compositions of poly aspartic acid and citric acid dual polymer systems as scale inhibitors were evaluated. Details of the synthesis, thermal stability, scale inhibition and the morphological characterization of single and dual polymers are presented in this scientific paper. It was found that the calcium sulphate scale inhibition rate was in the range 76.06–91.45%, while the calcium carbonate scale inhibition rate observed was in the range 23.37–30.0% at 65–70 °C. The finding suggests that the water soluble dual polymers are very effective in sulphate scale inhibition in comparison of calcium carbonate scale inhibition.

Study on Scale Inhibition Performance of Modified Polyaspartic Acid

Static and dynamic experiments were used to evaluate scale inhibition performance of modified polyaspartic acid (PASP-ASP). The static experiments showed that the PASP-ASP had good scale inhibition performance and the scale inhibition rate exceeded 98% when the PASP-ASP was 2 mg·L-1 and the solution temperature was 40 OC. In the dynamic experiments, almost no scale was formed on the heat transfer surface and the fouling thermal resistance decreases extraordinarily with PASP-ASP treatment experiment compared with the experiment without treatment. The PASP-ASP could be used in industrial cooling water systems.

Preparation of carboxymethyl-quaternized oligochitosan and its scale inhibition and antibacterial activity

Carboxymethyl-quaternized oligochitosan (CMQAOC) was prepared through carboxymethylization and N-quaternization of oligochitosan (OC) which was obtained from chitosan degradation. The structure was confirmed by Fourier transform infrared spectroscopy (FT-IR), 1H-NMR, and X-ray diffraction (XRD) analysis. The performances for both scale and microbial inhibition of CMQAOC were evaluated by static test and culture flask method, respectively. The results showed that the scale inhibition rate for calcium carbonate and calcium sulfate scale were both beyond 80% with a CMQAOC dosage of 20 mg/L. With a degree of substitution for quaternary ammonia of up to 0.74, the killing rate for saprophytic bacteria and sulfate-reducting bacteria was 98.9 and 100%, respectively. The ratio of biochemical oxygen demand/chemical oxygen demand (BOD5/COD) of CMQAOC was 0.45, showing that CMQAOC is as biodegradable as OC.

Research on Scale Inhibition of Green Scale Inhibitors Used in the Industrial Recycling Cooling System with Reclaimed Wastewater

The reclaimed water of domestic sewage reused in recycling cooling system has been widely spread and applied. Chemical scale inhibitors are the most economic and effective measures to prevent condensers and circulating pipes from scaling currently. Green scale inhibitor are highly regarded for their non-toxicity, phosphate-free, reproducibility and biodegradability. The paper selects two kinds of new green scale inhibitors used in the recycling cooling water of Beijing Thermoelectric Plant. By the measuring the scale inhibition rate, scaling amount, turbidity and SEM, it shows that Polyepoxysuccinic acid (PESA) is worth spreading and applying in the industrial recycling cooling system with reclaimed wastewater, for its high scale inhibition rate, good dispersion, low consumption, high economy and practicability.

Synthesis, Characterization and Properties of the IA / SAS Copolymer

A copolymer was prepared from itaconic acid (IA) and sodium allysulfonate (SAS). The structure of the IA/SAS copolymer was characterized by the means of FTIR. The performances of scale inhibition, dispersion and biodegradability of the IA/SAS copolymer were studied. The results showed that the IA/SAS copolymer had good scale inhibition and dispersing performance. The scale inhibition rate on calcium carbonate was 93% when the copolymer was 20 mg·L-1. The scale inhibition rate on calcium phosphate was 92% when the copolymer was 24 mg·L-1. The copolymer had good biodegradation performance and biodegradation rate could reach 69.5% after 28 days.

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.

Experimental Study on a New Corrosion and Scale Inhibitor

The mixture consisted of benzotriazole (BTA), chitosan (CTS), polyacrylic acid and zinc salt has been investigated as a corrosion and scale inhibitor of A3 carbon steel in cooling water. The scale and corrosion inhibition efficiency was evaluated by static anti-scaling teat together with rotary coupon test. Compared with the phosphorus corrosion and scale inhibitor, the corrosion inhibition rate and scale inhibition rate of it increased respectively by 2.51% and 1.16%. As the corrosion and scale inhibitor is phosphate-free, it won’t cause eutrophication, considering the product performance and environmental influence, the phosphate-free corrosion and scale inhibitor is superior to the traditional one.