【作者】 吴复忠；

【导师】 蔡九菊； 李军旗；

【作者基本信息】 东北大学 ， 热能工程， 2008， 博士

【摘要】 钢铁工业的烧结烟气和自备电厂的燃煤锅炉烟气是钢铁企业生产过程中SO2排放的主要来源,控制烧结工序和自备电厂的S02排放是我国钢铁企业控制污染的重点。电厂燃煤锅炉的S02排放控制措施和脱硫技术,国内外研究很多,有十几种脱硫技术(如石灰石—石膏法、活性炭法等)已得到商业化应用。国外钢铁联合企业烧结工序是通过源头控制原燃料的硫含量和末端烟气脱硫两个途径来控制S02的排放；国内烧结工序S02污染控制技术的研究和应用基本上还处于起步阶段。所以,选择投资少、运行成本低和资源化技术的烧结烟气脱硫工艺,是当前钢铁企业实现清洁生产亟待解决的问题。为此,本文在对国内外钢铁工业S02控制技术充分调研的基础上,对钢铁生产过程的硫素流进行了分析,揭示了烧结工序是S02排放的主要环节；提出了利用软锰矿吸收烧结烟气中的S02,菱锰矿作为添加剂调节矿浆pH值的新技术。该技术是将MnSO4的生产与S02烟气的治理结合起来,既能实现S02的无害化、减量化和资源化,又为贫锰矿资源的利用开拓了市场。论文主要研究内容如下：以工业代谢理论为基础,应用物质流分析方法,构建了硫素流分析模型,对钢铁企业内部的硫元素进行了工业代谢分析,为钢铁企业进行硫素流分析和合理治理SO2污染提供了分析方法和理论依据。以某钢铁联合企业为例,对生产流程及其重点工序的硫素流代谢过程、SO2生成及排放等问题进行了分析；编制了钢铁企业硫元素收支平衡表,绘制了钢铁生产硫素流图,理清了输入、输出的各股硫素流的来龙去脉。硫素流分析结果表明：生产主要工序的S02吨钢排放量为1.30kg/t钢,主要来源于烧结工序,生产每吨钢烧结工序SO2排放量是1.15kg/t钢。在我国废钢资源受限制和燃料质量下降的情况下,对烧结工序进行烟气脱硫,降低钢铁工业SO2的排放,是完全有必要的。对软锰矿烟气脱硫过程的热力学和反应机理进行了分析研究。确定了脱硫体系中存在两种脱硫途径：途径一是Mn02与S02直接发生氧化还原反应生成MnSO4,反应式为：MnO2+SO2=MnSO4,是脱硫体系的主要反应；途径二是S02被氧化成S03后,与H20生成H2SO4,反应式为：S02+1/2O2+H2O=H2SO4,是脱硫体系的副反应。副反应的存在尽管对脱硫能够起到一定的作用,但生成的H2SO4降低了脱硫体系的pH值,使S02在水中的溶解度下降,阻碍了S02向液相的传质,从而影响了软锰矿脱硫主反应的正常进行,最终脱硫率下降。在实验室对软锰矿烟气脱硫工艺进行了研究。对影响脱硫体系的吸收温度、液固比、锰矿粒度、烟气中的SO2含量等工艺条件进行考察,分析其对脱硫和浸锰过程的影响；对软锰矿烟气脱硫体系中加入添加剂菱锰矿调节矿浆pH值后的脱硫、浸锰效果进行了研究,确定添加剂菱锰矿的适宜比例。工艺影响实验研究结果表明：软锰矿、菱锰矿烟气脱硫较优工艺参数为：温度40-C、液固比5：1、锰矿平均粒径0.075mm、菱锰矿添加比例为20%,在此条件下进行连续实验操作时,可同时获得大于90%的脱硫率和80%的锰浸出率效果。实验室研究为该工艺的中试提供了技术支撑。对软锰矿、菱锰矿烟气脱硫副产品硫酸锰的进行了深度开发,对Fe3+、A13+的净化采用氨水中和法,重金属离子净化提出了用锰粉置换的新工艺,CaSO4、MgSO4等水的不溶物杂质采用静置的方法净化。通过对浸出液的净化,使其中铁和铝、重金属、水的不溶物等杂质含量达到痕量级。为进一步验证软锰矿、菱锰矿对烧结烟气脱硫的实验研究结果,加快其工业应用步伐,进行了中试研究。并对脱硫过程的环境影响、社会经济效益进行了分析。中试结果表明：整套脱硫设备连续运行稳定,中试工艺流程合理；脱硫率可长时间维持在92%以上,锰的最终浸出率在80%以上,硫酸锰产品可达到肥料级和饲料级添加剂标准(GB1622-86、GB5253—87)。软锰矿、菱锰矿烟气脱硫技术是一种符合我国国情,能够大力推广的循环经济烟气脱硫模式,对我国烧结烟气和燃煤锅炉烟气SO2的污染治理有重要的应用价值。更多还原

【Abstract】 The main source of SO2 in steel industry is from sinter process and the coal-burning boilers of self-equiped power plant. So how to control SO2 emission during sintering and electricity generating is the key to deal with the pollution in iron & steel factory. There has been a lot of desulfurization technologies that are used to control SO2 emission for coal-burning boilers of self-equiped power plant, and dozons of technologies has been applied at home and abroad. There are two methods to control SO2 emission during sintering in iron and steel complex in countries abroad:controlling the Sulfur content in the raw materials and desulfurizing fume in the end. At home, the research is still on the initial stage. Study on how to develop a desulfurizing technique with less investment, less operating costs and resource regeneration, is very important. Therefore, adopting the advanced technology to control and reduce the emission of SO2 is a task needing to resolve for the sake of clear production in iron & steel factory.In order to do so, some investigation is undertook to make sure wher the Sulfur comes and whers goes in iron and steel factory, and to know the progress in fume desulfurization at home and abroad. Based on the analysis on the Sulfur flows in steel production, this paper puts forward a new desulfurizing technology:pyrolusit as oxidant and rhodochrosite as additives are used to absorb the SO2 in the fume in sinter process, so as to adjust the pH value of the pulp to make MnSO4. It is actually a new technology. In this technology, the production of MnS04 is connected with the treatment of SO2, so as to remove the reduction roasting process in the production of MnS04, to save energy, and to produce the new resource of H2SO4. At the same time, SO2 is absorbed without harm, and become a new resource. The main research content is as follows:The analytic model of Sulphur flows for a process is established based on the theory of Industrial Metabolism and the method of Material Flow Analysis. It will provide theoretic reference to further research the reducing SO2 pollution letting for iron & steel factory.According to the practical data of an iron & steel factory, the model was used to analyze the Sulphur in the factory, draw the sketch of Sulphur flows, and dissolve the cause and effect. The analysis results are as follows:the SO2 emission is about 1.30kg per ton steel for the main processes, and 1.15kg per ton steel for sinter process.It is essential to FGD in sinter process in the lack of scrap and decline of fuel quality.The reaction thermodynamics and mechanism of desulfurization process with pyrolusite are analyzed. We make sure there are two process of desulfurization:the main reaction as(MnO2+SO2=MnSO4, and the minor reaction (SO2+1/2O2+H2O=H2SO4). Though the minor reaction can promote the desulfurizing process, H2SO4 produced in the reaction cut down the PH value so as to reduce the solubility of SO2 in water, and in this way hold back the operation of the main and reduce the desulfurization efficiency.The experimental study of desulfurization of fume with pyrolusite is done. The technique conditions that affects desulfurizating process and leaching Mn2+process in the system, such as absorbing temperature, ratio of liquid to solid, size of Manganese and content of SO2 in the fume is analyzed. The effect of desulfurization and leaching Mn2+ is studied when rhodochrosite as additives is put in the system to adjust the pH value, so as to make sure the quatity of the additives. Through the experimental study, the technique condtions under which the high desulfurization rate and the rate of leaching Mn2+ can be obtained is set up:the temperature is at 40℃, the ratio of liquid to solid 5:1, the size of Manganese 0.075mm and the ratio of rhodochrosite 20%, and in this way offer the technique support to the middle test.Some deep developing research on the by product of the desulfurization- MnSO4 as fertilizer and feed is done. In the research, Fe and Al is based on the method of Ammonia counteraction; the purification of heavy metal ions is repalced by the Manganese powder; and the insoluble things such as CaSO44 and MgSO can be purified by placing staticly. By the purification, the heavy metal such as Fe and Al, and the insoluble things will arrive the level of trace.The middle test is done to testify the experimental results and speed up the pace of industrial application. The impaction of the desulfurization process has on the environment and the economic benefits is analyzed. The middle test shows that:the whole set of devices runs smoothly; the process for the middle test is reasonable; the desulfurization rate can be above 92% for long time; the the rate of leaching Mn2+ can be over 80%; The product MnSO4 can arrive the fertilizer level (GB1622-86) and feed level (GB5252-876).The desulfurization technology of fume with pyrolusite and rhodochrosite is a technology which meets the current conditions in China, and can be promoted widely. It has practical significance for the treatment of the fume from the sinter process and the boiler that burns coal in China.更多还原