【作者】 杨剑；

【导师】 刘清才；

【作者基本信息】 重庆大学 ， 冶金工程， 2005， 硕士

【摘要】 我国电力生产以燃煤发电为主,由于中国煤炭资源的特点是高灰分、高硫,因此,近年来,燃煤电厂SO2的污染问题日益突出。烟气脱硫是控制燃煤电厂SO2排放的有效方法。湿式石灰石烟气脱硫工艺是当今燃煤电厂应用最为广泛的烟气脱硫技术。石灰石作为湿法脱硫的吸收剂,对烟气脱硫的过程和效果有着重要影响。石灰石-石膏湿法脱硫系统中,石灰石的消溶速度制约着整个系统对二氧化硫的吸收速度,而衡量石灰石消溶性能的一个重要参数就是石灰石的活性。石灰石的活性越高,越利于二氧化硫的吸收。本论文从石灰石的基本物理性质着手,研究了石灰石成分、粒径、石灰石浆液粘度对石灰石活性的影响。研究和分析了不同条件下石灰石浆液粘度的变化规律。实验结果表明,当石灰石浆液配比在15%~25%范围内时,石灰石饱和溶解度的变化对石灰石浆液的粘度影响不大;对浆液粘度影响最大的因素为浆液配比,反应温度次之,石灰石粒径对其影响最小。研究和分析了石灰石吸收SO2 的反应机理,建立了石灰石消溶的动力学数学模型,并利用实验数据对消溶模型进行了验证,经程序计算,预测值与实验值符合较好。定义了石灰石反应的特征常数,并用其代表石灰石的活性,认为其反映了石灰石反应速率变化的总趋势。其值越小,说明石灰石活性越大,即石灰石与SO2烟气的反应速率越快,反之则说明石灰石活性越小。通过实验研究,证明当石灰石浆液配比在15%~25%范围内时,石灰石饱和溶解度的变化对石灰石浆液的粘度影响不大;并证明当石灰石中CaCO3含量在84.81%~97.14%范围内、石灰石粒径在45~75μm 范围内时,石灰石活性受其成分、粒径的影响不明显,而pH 值、反应温度、浆液配比对石灰石的活性影响最为显著,并据此建立了石灰石活性的经验模型。更多还原

【Abstract】 The power generation in China is mostly generated by coal-fired plant. As the coal resources of high quantity of ash and sulfur, the pollution of sulfur dioxide, which produced by coal-fired power plant, becomes severe nowadays. The flue gas desulfurization (FGD) is an effective way to control the emitted sulfur dioxide. The wet FGD process is the most extensively used technology for desulfurization. As the absorbent in the FGD process, the limestone is of significance to the FGD process. In the limestone-gypsum wet FGD system, the absorption rate of sulfur dioxide is restricted by the melting rate of limestone. The melting rate is judged by the activity of limestone. The more active the limestone is, the easier the sulfur dioxide is absorbed. The basic physical properties such as the component, the particle size and the solubility have been studied. The influencing factors of limestone slurry viscosity also have been discussed. The experiment results indicated that the solubility of limestone influenced the slurry viscosity little when the mixture ratio of slurry was between 15% and 25%. Considering the impact extents on the viscosity, the mixture ratio of slurry affected the viscosity most, the reaction temperature took the second place, and the particle size ranked the third. The reaction mechanism of limestone absorbing sulfur dioxide has been analyzed. The mathematical model of the absorbing process has been built. It’s been tested and verified by the experimental results. The activity of limestone has been defined. It reflected the changing tendency of reaction rate of limestone. The larger the value of the activity was, the more activate the limestone was. That meant the limestone reacted with sulfur dioxide faster. The experiments showed that the component and the particle size of limestone rarely impacted on the activity of limestone, when the percentage composition of calcium carbonate in the limestone varied from 84.81% to 97.14% and the particle size of limestone was between 45 and 75μm. The activity was influenced significantly by the pH, reaction temperature and the mixture ratio of slurry. By virtues of the results, the empirical model has been built.更多还原