池式沸腾下PAA与PBTCA对CaCO3结垢的影响

Formation of mineral scales on heat exchangers is a persistent and expensive problem.In the present paper,the calcium carbonate scale inhibition by two inhibitors,polyacrylic acid(PAA) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) has been studied in a pool boiling system.It is found that PBTCA has a better inhibition effect than PAA under the identical conditions.X-ray diffraction (XRD) and Fourier transform-infrared(FTIR) analyses demonstrate that the content of vaterite increases as inhibition effects increase.The metastable crystal froms of vaterite and aragonite are stabilized kinetically in the presence of inhibitors.The relationship between the inhibition effect and the fractal dimension has also been investigated.The result shows that the fractal dimension is higher in the presence of inhibitors.The better the inhibition efect,the higher the fractal dimension.The step morphology was observed by atomic force microscopy(AFM) images.It is shown that the step space on the calcium carbonate surface increases in the presence of inhibitors.Moreover,with the increase of inhibition effect,both the step space and the fractal dimension increase.The step bunching is found on the calcium carbonate by AFM.The better the inhibition effect of the inhibitor,the slower the step velocity in the unbunched location.As a result,the step space becomes wider in the presence of PBCA than that in the presence of PAA.     

换热面上碳酸钙的结垢行为及垢形

研究了循环冷却水及池式沸腾系统中换热面上碳酸钙的结垢行为 ,对垢形进行了分析 .考察了分子自组装膜 (SAM)低能表面循环冷却水系统中碳酸钙结垢诱导期及过诱导期特性 ,研究了污垢的脱除现象 .结果表明 ,在诱导期内进行脱除可减少污垢的发生 ,在诱导期后进行脱除会增加污垢的发生 .扫描电镜 (SEM )表明 ,在阻垢剂存在下 ,循环冷却水系统中形成的碳酸钙垢形发生了变化 .利用扫描电镜与原子力显微镜 (AFM)对池式沸腾系统中生成的碳酸钙形貌进行了研究 ,发现在阻垢剂存在下以方解石为主的垢形变成了以文石和球霰石为主的垢型 ,同时碳酸钙表面的台阶发生了聚并现象 .垢形分维分析表明 ,在阻垢剂存在下两种系统中生成的碳酸钙垢形的分维值都增大了 .     

聚羧酸类阻垢剂对碳酸钙的沉淀及溶解过程的影响研究

利用VB语言自编的计算机程序对不同形态CaCO3在各种条件下的溶解度 进行了计算,并对过饱和体系进行了分析,在此基础上研究了PAA1、PAA2、PMA－AA,PPMA四种聚羧酸类阻垢剂对CaCO3的再溶解和沉淀过程的影响,从阻垢剂对CaCO3沉淀形态影响的角度,解释了阻垢剂对CaCO3过饱和溶液亚稳态的影响和阻垢剂的阻垢作用。     

Effect of Organic Additives on Electrochemical Surface Precipitation and Polymorphism of CaCO3

The inhibition effect of three organic additives on the precipitation and polymorphism of CaCO₃ deposited on gold surfaces was investigated using electrochemical and microscopic techniques. Additives, two polyacrylic acid (PAA) polymers with different molecular weights (Mw 2100, Mw 30,000), and 1,2,4,5‐benzenetetracarboxylic acid (BTCA), were either added to the solution before or during deposition. In the presence of 100 ppm of one of the three additives in solution, almost no scale was observed on the surface for at least 24 hours. In the presence of lower concentrations of PAA Mw 2100, only distorted calcite crystals were obtained while with PAA Mw 30,000 the polymorph was spherical vaterite. A mixture of calcite and vaterite was observed with the BTCA additive. Addition of the polymers inhibits further nucleation and growth even if added after partial deposition of CaCO₃ while BTCA has no effect once nucleation has started. The results indicate that the inhibit ion effect of the PAA polymers is due to adsorption on the electrode surface while the effect of BTCA is related to chelation of calcium ions in solution.     

模拟高矿化度矿井水阻垢缓蚀剂的研究

采用碳酸钙沉积法测定5种单一阻垢剂对CaCO3的阻垢效果,聚环氧琥珀酸（PESA）的最佳使用质量浓度为15mg／L时,其阻垢率达到75．3％;在含磷类阻垢剂中,2-膦酸基-1,2,4-三羧基丁烷（PBTCA）的最佳使用质量浓度为20mg／L时,其阻垢率达到76．1％。PESA与PBTCA的浓度比为10：15时,阻垢率可达94．2％。通过正交实验和平行实验,确定三元阻垢剂的最佳配比,即ρ（PESA）：ρ（PBTCA）：ρ（TS-623）（丙烯酸-AMPS三元共聚物）=8：12：8,阻垢率达到96．5％,阻垢效果最佳,且磷含量较低,价格合理,是较为理想的复配型阻垢剂。静态阻垢实验和中试规模的动态试验结果表明,本实验研究的阻垢缓蚀剂能完全适用于工业循环冷却水系统。     

流动过冷沸腾传热强化及阻垢

在流动沸腾传热实验中,考察了CaCO3污垢溶液的形成过程及各种工艺条件对流动过冷沸腾传热的影响. 研究条件包括流体速度、溶液温度、CaCO3溶液浓度及热通量,实验中发现了一些规律. 同时还考察了不同阻垢剂[聚天冬氨酸(PASP)、2-膦酸丁烷-1,2,4-三羧酸(PBTCA)及氨基三甲叉膦酸(ATMP)]对流动过冷沸腾传热的影响. 结果表明,所选阻垢剂均能抑制污垢的生成并降低了污垢热阻,而且存在最佳浓度范围. 但不同阻垢剂的阻垢效果不尽相同,在本实验条件下,ATMP的阻垢效果最好,PBTCA次之,PASP的阻垢效果较差.     

聚天冬氨酸复配物及其阻垢缓蚀性能

通过合成丙烯酸-丙烯酸乙酯-衣康酸（AA-AE-IA）三元共聚物阻垢分散剂，开发出一种具有优良阻垢分散和缓蚀性能的新型聚天冬氨酸复配物（PASP＋AA-AE-IA＋PBTCA），考察了不同条件下聚天冬氨酸复配物对碳酸钙和硫酸钙的阻垢性能。利用扫描电子显微镜对碳酸钙晶型进行了分析，结果表明：聚天冬氨酸复配物可使碳酸钙晶体发生明显的扭曲现象，碳酸钙结晶更加细小分散。     

反应-萃取-结晶过程制备碳酸钙的晶型转变与结晶机理

氨碱法制碱过程中产生的大量蒸氨废液制约了纯碱工业的发展。本文对反应-萃取-结晶耦合工艺产物碳酸钙的晶型转变和结晶机理进行了研究。结果表明,在此耦合过程中,二氧化碳优先被有机相吸收,然后传递到水相进行反应,首先生成的是碳酸氢钙,之后迅速分解为无定形碳酸钙。温度对碳酸钙晶型影响显著,温度较高时,无定形碳酸钙优先转变为针状文石;温度较低时,无定形碳酸钙优先转变为球状球霰石。随后文石和球霰石均会通过溶解-重结晶作用逐渐转变为稳定的菱形方解石。常温下,反应过程中同时进行着新的球霰石的生成和球霰石转变为方解石两个过程,参与反应的二氧化碳浓度越高,晶体中球霰石的含量越高。     

三氯异氰尿酸对有机磷缓蚀阻垢剂性能的影响

试验研究了三氯异氰尿酸(TCCA)对羟基亚乙基二膦酸(HEDP)、2-膦酰基丁烷-1,2,4-三羧酸(PBTCA)、羟基膦乙酸(HPAA)和多氨基多醚基亚甲基膦酸(PAPEMP)四种有机磷缓蚀阻垢剂的分解作用和对它们缓蚀、阻垢性能的影响.结果表明,三氯异氰尿酸对有机磷类缓蚀阻垢剂有分解作用,其分解程度为PAPEMP＞HPAA＞HEDP＞PBTCA;三氯异氰尿酸可使水的pH降低,造成碳钢迅速腐蚀;随着水中三氯异氰尿酸浓度的增加,HEDP、PBTCA和HPAA的阻CaCO3垢率先增加而后降低,PAPEMP的阻CaCO3垢率则持续降低.     

阻垢剂协同效应及阻垢复配方案的研究

对羟基乙叉二膦酸(HEDP)、2-膦酸基丁烷-1,2,4-三羧酸(PBTCA)、聚马来酸酐(HPMA)和2-丙烯酰胺-2-甲基丙基磺酸(AMPS)进行复配,研究药剂间的阻碳酸钙垢协同效应.结果表明,HPMA与HEDP、AMPS与PBTCA、HPMA与PBTCA两两之间存在明显的协同效应;PBTCA与HEDP之间存在一定的协同效应;AMPS与HEDP、AMPS与HPMA两两之间不存在协同效应.HEDP、HPMA和PBTCA按1∶1∶1复配,阻垢率高达98.4％.     

极限碳酸盐硬度法评定阻垢剂的阻垢性能

着重介绍了极限碳酸盐硬度法及其在阻垢剂评价筛选中的应用,并对PAPEMP,HPMA(水溶出)．HPMA(油溶出),T-225,HEDP,PBTCA,HPAA等阻垢剂的阻垢性能进行了评定。由实验的结果来看．极限碳酸盐硬度法简便、快捷、重现性好,可信度高。     

Calcium carbonate inhibition by a phosphonate-terminated poly(maleic-co-sulfonate) polymeric inhibitor

The precipitation of calcium carbonate scale on heat transfer surfaces widely occurs in numerous industrial processes. For the control of calcium carbonate scale and in response to environmental guidelines, the new low phosphonic copolymer was prepared through reaction of maleic anhydride with sodium p-styrene sulfonate in water with redox system of hypophosphorous and hydrogen peroxide as initiator. The anti-scale property of the low phosphonic copolymer towards CaCO₃ in the artificial cooling water was studied through static scale inhibition tests, and the effect on formation of CaCO₃ was investigated with combination of scanning electronic microscopy (SEM), X-ray powder diffraction (XRD) analysis and Fourier transform infrared spectrometer, respectively. The results showed that the low phosphonic copolymer was excellent calcium carbonate scale inhibitor in artificial cooling water. The crystallization of CaCO₃ in the absence of inhibitor was rhombohedral calcite crystal, whereas a mixture of calcite with vaterite crystals was found in the presence of the low phosphonic copolymer. For actions of carboxyl and phosphonic acid groups, the calcite was inhibited and the metastable vaterite was stabilized in the presence of the low phosphonic copolymer during the CaCO₃ formation process.     

Nonenzymatic Transformation of Amorphous CaCO3 into Calcium Phosphate Mineral after Exposure to Sodium Phosphate in Vitro: Implications for in Vivo Hydroxyapatite Bone Formation

Studies indicate that mammalian bone formation is initiated at calcium carbonate bioseeds, a process that is driven enzymatically by carbonic anhydrase (CA). We show that amorphous calcium carbonate (ACC) and bicarbonate (HCO₃^?) cause induction of expression of the CA in human osteogenic SaOS‐2 cells. The mineral deposits formed on the surface of the cells are rich in C, Ca and P. FTIR analysis revealed that ACC, vaterite, and aragonite, after exposure to phosphate, undergo transformation into calcium phosphate. This exchange was not seen for calcite. The changes to ACC, vaterite, and aragonite depended on the concentration of phosphate. The rate of incorporation of phosphate into ACC, vaterite, and aragonite, is significantly accelerated in the presence of a peptide rich in aspartic acid and glutamic acid. We propose that the initial CaCO₃ bioseed formation is driven by CA, and that the subsequent conversion to calcium phosphate/calcium hydroxyapatite (exchange of carbonate by phosphate) is a non‐enzymatic exchange process.     

2,4,6-三(4-羧基-1-羧丙氨基)-1,3,5-三嗪的合成及阻垢性能

用三聚氯氰和谷氨酸为原料,合成2,4,6-三(4-羧基-1-羧丙氨基)-1,3,5-三嗪(TGAT)。讨论了反应物配比、反应时间、反应温度对产率的影响。FTIR及1HNMR表征了衍生物的结构。通过对产物进行阻垢实验发现,该类型阻垢剂对碳酸钙有良好的阻垢效果。通过扫描电镜考察了阻垢剂碳酸钙垢晶形的变化,结果表明,TGAT可使碳酸钙垢晶形完全扭曲,形成球霰石晶体,从而达到阻垢目的。     

Growing Innovative Calcium Carbonate Morphologies by Utilizing the Colloidal Gas Aphron System as a Surfactant-Based Template Method

Many studies have been conducted to study the various polymorphs and morphologies of calcium carbonate crystals in nature and living organisms. In this experimental work, a novel method has been employed to crystallize calcium carbonate by using colloidal gas aphron dispersion. The polymorph and morphology of prepared particles were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectrometry techniques. SEM and XRD analyses demonstrated that the morphology of synthesized CaCO₃ can be changed from spherical (vaterite phase) to novel rod and plate-like shapes (mixture of vaterite and calcite phases) with changes in the surfactant concentration. The quantitative examination results of different calcium carbonate polymorph orientations showed that the precursor concentrations had no significant effect on the orientation of calcite phase, but rather they affected the orientation development of vaterite phase at a higher surfactant concentration.     

Investigation of induction period and morphology of CaCO3 fouling on heated surface

The accumulation of unwanted crystalline deposits (fouling) reduces the efficiency of heat exchanger considerably. In order to mitigate fouling, many measures have been taken including the use of low-energy surface and antifoulant. In this investigation, the CaCO₃ fouling experiments in both cooling water and pool-boiling systems were performed, the induction period as well as the removal of fouling was studied, and the fouling morphology was also investigated by scanning electron microscopy and atomic force microscopy (AFM). Compared with the copper surface, the self-assembled monolayers low-energy surface can prolong the induction period of fouling in the cooling water system. The induction period increases with decreasing initial surface temperature and fluid velocity. When the heat flux is fixed in different experiments, an increase in the fluid velocity will result in a decrease in the initial surface temperature. Under this condition, owing to the interactional effects between surface temperature and fluid velocity, the induction period increases with increasing fluid velocity. The removal experiments were carried out both in the induction period and in the post-induction period. The results show that only in the induction period can the fouling resistance be reduced owing to the weaker adhesion strength of fouling. In the presence of antifoulant polyacrylic acid (PAA), the crystal forms are changed and the fractal dimensions of CaCO₃ morphologies increase for both the cooling water and the pool-boiling systems. AFM images show that the steps are bunched for CaCO₃ formed in the pool-boiling system, and in the presence of PAA, the step spacing is widened compared to the case in the absence of PAA.     

Low‐phosphorus maleic acid and sodium ρ‐styrenesulfonate copolymer as calcium carbonate scale inhibitor

In this article, a multifunctional and environment‐friendly agent for industry circulation cooling water, maleic acid and sodium ρ‐styrenesulfonate copolymer containing low‐phosphorus was synthesized in aqueous solution with hypophosphorous acid/hydrogen peroxide as redox initiators. The effects of monomer feed ratio, temperature, dose of hypophosphorous acid, and drop speed of hydrogen peroxide on calcium carbonate inhibition were investigated, and the experimental conditions were optimized using orthogonal method. The composition and structure of the copolymer were analyzed by enery‐dispersive X‐ray analysis, fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The results of the static scale inhibition tests showed that the copolymer was effective in inhibiting the formation of calcium carbonate scale. The calcium carbonate precipitates formed in the static tests were examined by scanning electronic microscopy and X‐ray diffraction spectra. The results indicate that in the presence of the copolymer the calcium carbonate precipitate is the mixture of calcite and vaterite that could be stabilized kinetically in the presence of the copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

含膦酰基聚天冬氨酸的阻垢性能研究

自行制备了含膦酰基聚天冬氨酸。与PBTCA、HPA相比,含膦酰基聚天冬氨酸的阻CaCO3垢性能相当,具有比较突出的阻Ca3(PO4)2垢以及稳定水中Zn^2 的能力。含膦酰基聚天冬氨酸与PBTCA、HPA等药剂复配得到的低磷药剂性能达到常用有机磷药剂的水平。     

羧甲基葡聚糖的快速沉降法阻垢特性研究

工业循环冷却水中的碳酸钙污垢一直是困扰工业生产者的重要问题,使用快速沉降法（FCP）研究了不同浓度的羧甲基葡聚糖对于碳酸钙污垢的抑制作用。控制溶液中的钙离子浓度为200 mg/L,羧甲基葡聚糖的浓度分别为0.5、1、2和4 mg/L时,对羧甲基葡聚糖的阻垢性能进行分析。结果表明,羧甲基葡聚糖对于减缓碳酸钙的成核过程有明显效果,此外,它也显著降低了碳酸钙成核后晶体的生长速率。当羧甲基葡聚糖的浓度为4 mg/L时,羧甲基葡聚糖对于碳酸钙的成核及晶面生长起到了完全抑制的作用,对于工业应用中碳酸钙的防垢处理,提升换热效率具有借鉴意义。     

阻垢剂阻垢性能比较

文章通过碳酸钙沉积法对PBTCA、ATMT、HEDP、PAPE、HPMA、AA/AMPS、HPMA、PESA、PSAP的阻垢性能进行测定,分别用螯合阻垢性能及非粘附阻垢性能表示各阻垢剂的阻垢能力。并提出非粘附阻垢性能比螯合阻垢性能更能反映阻垢剂的阻垢能力。