Effects of PAA and PBTCA on CaCO_3 Scaling in Pool Boiling System  

作　　者：杨庆峰 顾安忠 丁洁 沈自求 

机构地区：[1]Institute of Refrigeration and Cryogenic Engineering, Shanghai Jiaotong University, Shanghai 200030, China [2]Institute of Chemical Engineering, Dalian University of Technology, Dalian 116012, China

出　　处：《Chinese Journal of Chemical Engineering》2002年第2期190-197,共8页中国化学工程学报（英文版）

摘　　要：Formation of mineral scales on heat exchangers is a persistent and expensive problem. In the presentpaper, 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 abetter 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. Themetastable crystal forms of vaterite and aragonite are stabilized kinetically in the presence of inhibitors. Therelationship between the inhibition effect and the fractal dimension has also been investigated. The result showsthat the fractal dimension is higher in the presence of inhibitors. The better the inhibition effect, the higher thefractal dimension. The step morphology was observed by atomic force microscopy (AFM) images. It is shown thatthe step space on the calcium carbonate surface increases in the presence of inhibitors. Moreover, with the increaseof inhibition effect, both the step space and the fractal dimension increase. The step bunching is found on thecalcium carbonate by AFM. The better the inhibition effect of the inhibitor, the slower the step velocity in theunbunched location. As a result, the step space becomes wider in the presence of PBTCA than that in the presenceof PAA.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 forms 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 effect, 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 PBTCA than that in the presence of PAA.

关 键 词：calcium carbonate SCALING INHIBITOR atomic force microscopy FRACTAL 

分 类 号：TQ021[化学工程]