【作者】 王鹏；

【导师】 李永华；

【作者基本信息】 华北电力大学 ， 热能工程， 2011， 硕士

【摘要】 目前,燃煤污染是我国环境污染的重要方面,其中减少含硫污染物的排放是治理燃煤污染的一项重要内容。电石渣是一种氢氧化钙含量很高的工业废渣,电石渣的大量堆积严重污染周边环境,如果能够利用其脱硫,不仅可以减少环境污染,而且能达到以废制废的目的。本文采用热分析法,在热天平上进行电石渣脱硫的热重实验研究。实验结果显示,电石渣脱硫反应分为煅烧和吸收两阶段。在实验工况下,温度越高,钙的转化率越高;SO₂浓度越高,反应在化学反应控制阶段持续的时间越短,反应更容易进入到产物层扩散控制阶段。通过对实验数据的分析,确定了电石渣的脱硫过程,并且讨论了其脱硫机理。利用数学模型研究电石渣脱硫反应动力学特性,计算并分析了动力学参数——活化能E、表面化学反应速率常数ks和产物层扩散系数Ds。结果表明,模型能够很好的描述化学反应控制阶段和产物层扩散控制阶段的脱硫反应过程。对反应过程做出合理假设,结合未反应收缩核模型和孔分布模型,并采用质量守恒定律和扩散方程建立CaO吸收SO₂的颗粒—孔分布模型。模型计算结果跟实验结果吻合的较好,模型能够较好的描述电石渣的脱硫过程。最后,利用某电厂的实际运行数据再一次验证了模型的准确性。现场运行数据还表明,电石渣的加入对锅炉运行的影响很小。本研究为开发废弃物型脱硫剂提供理论基础,对促进脱硫技术发展具有重要的理论价值和工程应用指导作用。更多还原

【Abstract】 At present, coal-fired pollution is the focus of Chinese environmental pollution, in which controlling emissions of sulfur dioxide is a very important element. Carbide slag is industrial waste which includes high sulfur, the bulk deposition of it make heavy-polluted of the envirement around, if we can use it to do desulfurization, not only can decrease the pollution, but also makes good waste utilization.This article uses the thermal annlysis, makes the thermal analysis research of the carbide slag desulfurization in the thermobalance. The results of the experiment show carbide slag desulfurization reaction is divided into two stages: Calcination and Absorption. In the experimental condition, the higher the temperature is, the higher the conversion of calcium; the higher SO₂ concentration is, the shorter the reaction in chemical reaction control stage continuous time is, reaction easier to enter the product layer controlling stage.Based on the analysis of the experimental data, we determine the desulfurization process and discuss the desulfurization mechanism. Using the mathematicl models to study the carbide slag desulfuration reaction dynamical characteristic, we calculate and analyze their dynamic parameter—activation energy E, chemical reaction rate constant ks, product layer diffusion coefficient Ds. The results indicate that the mathematical model can describe the desulfurization reaction process well at the chemical reaction controlling stage and at the product layer diffusion controlling stage.Make reasonable hypothesis of the reaction process, combing unreacted shrinking core model and pore distribution model and use conservation of mass and the diffusion equation to establish CaO absorb the SO₂ particle-pore distribution model. Calculation results of the model and the experimental results are well matched. The model can describe carbide slag desulfurization process well. Finally, using a power plant actual data also proved the accuracy of the model once again. The site operation data also shows that, adding the calcium carbide slag make little effect for the boiler operation.This study provides theoretical basis for developing the waste type desulfurizer, meanwhile, it has very important theoretical value for promoting the development of desulfurization technology and directive function for engineering application.更多还原