【作者】 覃海华；

【导师】 李彩亭；

【作者基本信息】 湖南大学 ， 环境工程， 2010， 硕士

【摘要】 本文介绍了二氧化硫的来源与危害,并对脱硫技术的研究进展进行了概述,分析了湿法石灰／石灰石脱硫技术中存在的问题,指出向脱硫系统中添加阻垢剂是解决结垢堵塞问题的可行办法。综述了现在较为常用的湿法脱硫系统用阻垢剂,并详细介绍了聚天冬氨酸(PASP)的合成、性能及应用。本文采用静态阻垢法研究了聚天冬氨酸的阻垢性能,与聚丙烯酸(PAA)及2-膦酸基丁烷-1,2,4-三羧酸(PBTCA)进行比较,并采用旋转挂片法在模拟脱硫浆液中研究了聚天冬氨酸的阻垢过程。静态阻垢性能实验结果表明：对碳酸钙垢,随着阻垢剂质量浓度增加,三种阻垢剂的阻垢性能都表现出溶限效应；随着Ca2+浓度升高、HC03-浓度增大、pH上升、恒温温度升高、反应时间延长,阻垢剂的阻垢率都表现出下降趋势；三种阻垢剂的静态阻垢性能为PBTCA>PAA>PASP。对硫酸钙垢,随着阻垢剂质量浓度增加,三种阻垢剂的阻垢性能也都表现出溶限效应；随着Ca2+浓度、SO42-浓度的增加,阻垢剂的阻垢率表现出下降趋势；随着恒温温度升高、反应时间延长,三种阻垢剂的阻垢率表现出先增大后减小的阻垢效应；在实验pH的范围内,pH变化对PAA、PASP的阻CaSO4垢性能影响很小。pH>7.0时,pH对PBTCA阻垢率的影响较小,在pH为6和5时,PBTCA的阻垢率较小。模拟湿法石灰脱硫浆液系统中,在阻垢剂作用下,在一定的浆液恒温温度、恒温时间以及搅拌转速条件下,挂片上的结垢量随阻垢剂浓度的增大先增大后减小；恒温温度、恒温时间以及搅拌转速对单位面积挂片上的结垢量有很大影响,单位面积挂片上结垢量随恒温温度的增大而增加,随恒温时间的延长而增加,随搅拌速度的增加而减少,阻垢效果是阻垢剂作用与恒温温度、恒温时间以及搅拌转速共同作用的结果；在相同的实验条件下,PASP与PAA、PBTCA表现出了相似的阻垢效应变化规律。单位面积麻石片上的结垢量大于不锈钢挂片上的结垢量；扫描电镜图片及X射线衍射分析结果表明加阻垢剂后颗粒状晶体易形成团块状聚集在一起,不易粘附在挂片材料表面。考虑到阻垢效应及环境效益,可优先考虑使用PASP作阻垢剂。更多还原

【Abstract】 This article summarizes the sources and hazards of sulfur dioxide, and desulfurization technology overview on the research progress. Problems existing in wet flue gas desulfurization (FGD) with lime/limestone technology are analyzed. It is thought to be a feasible solution to scaling and blocking problem to add inhibitors into wet FGD system. Scaling inhibitors in wet FGD system are introduced. We also introduce polyaspartic acid, about its synthesis, properties and applications. In this paper, we studied the scale-inhibiting properties of polyaspartic acid, and we made the comparison of those of polyacrylic acid (PAA) and 2-phosphonobutane-1,2, 4-tricarboxylic acid (PBTCA). In slurry of wet FGD system, the scaling laws under these inhibitors and the scale inhibiting process of PASP were analyzed.By means of Static Scale-inhibiting method, the scale-inhibiting properties of PASP, PAA and PBTCA were detected. Simultaneously, scaling laws under these inhibitors were analyzed by means of rotation specimen method. Results showed that these inhibitors had threshold effect as the dosage of inhibitors increasing. The order of scale inhibition effects against CaCO3 of three inhibitors was as follows: PBTCA>PAA>PASP. As water-bath temperature increased and reaction time extended, scale inhibition effects against CaSO4 of these inhibitors increased at first, and then decreased. pH had little impact on scale inhibition effects against CaSO4 of PAA and PBTCA. When pH>7.0, the influence of pH on scale inhibition effects against CaSO4 of PBTCA can be negligible. When pH6.0 and 5.0, that can be visible.The effect of several factors on scale inhibition effect of polyaspartic acid in wet flue gas desulphurization system with lime is discussed in this paper. Experimental data demonstrated that when water-bath temperature, reaction time and stirring speed increased, the mass of hanging on-chip scaling increased at the began, and then decreased as the dosage of inhibitors increasing. Water-bath temperature, reaction time and rotating speed played an important role on scaling; scale inhibition effect of polyaspartic acid in wet flue gas desulphurization system with lime was the combined action of water-bath temperature, reaction time, rotating speed and scale inhibitor. Under the same experimental conditions (60℃,5h,100 r/min), PASP, PAA and PBTCA showed the similar variation of inhibition effect. Under the same conditions (60℃,5h,100 r/min), the mass of stainless hanging on-chip scaling was bigger than that of granite hanging on-chip. The structures and properties of scale samples crystals were investigated by SEM (scanning electron microscopy) and xrd (X-ray diffraction), the analyses showed that the structure of scale samples crystals may vary with or without PASP. With PASP, it was easy to form granular crystals and agglomerate together, not easy to adhere to slide surface. So it came to scale inhibition. The scale inhibiting process of PASP was analyzed.更多还原