【作者】 陶从喜；

【导师】 赵林； 俞为民；

【作者基本信息】 天津大学 ， 环境科学， 2011， 博士

【摘要】 预分解技术是目前国际上最先进的水泥制造技术。尽管近年来我国水泥预分解技术取得了较快的发展,但在热耗、电耗及污染物如氮氧化物排放等方面同国际最先进水平仍存在一定的差距。对水泥预分解系统进行优化是实现水泥生产线节能、降耗、减少污染物排放的重要途径之一。因此开展水泥窑预分解系统节能减排技术的优化研究并将之应用于实际工程项目中,对实现水泥工业的低碳经济以及与资源环境的协调发展具有重大的现实意义。本文采用实验室实验、理论分析、计算机模拟研究及工程实际检测等方法对环保型水泥预分解系统进行了优化研究。主要内容如下:(1)采用撒料装置实验平台研究了不同结构的撒料装置及不同撒料板角度、插入深度等情况下的物料分散状况。通过数学分析的方法得知,撒料板角度为5°、插入深度为200 mm时,物料的分散性最佳。通过工程实践应用证明改进型的撒料装置能使预热器出口温度降低15~20℃。(2)通过旋风筒冷模实验的数据修正了计算流体动力学(CFD)计算模型中的湍流模型参数,采用雷诺应力模型(RSM)和离散相模型(DPM)对天津水泥工业设计研究院有限公司开发的六级预热器优化前后的流场、热交换效率和分离效率进行了研究。改进后的六级预热器系统总体压损降低了13.8%,系统换热效果降低1.7%,说明优化后的六级预热器系统节能减排效果更好。(3)通过理论分析推导得到了旋风筒阻力特性的计算公式,提出了旋风筒能量利用效率的有效能及无效能的概念,指出旋风筒开发既要考虑降低其阻力同时又要尽可能提高旋风筒的有效能量利用率。(4)通过实验和CFD模拟研究了燃料燃烧特性与分解炉开发设计的相关性。合理有效的分解炉既要能满足各种燃料的充分安全着火燃烧并燃尽的要求,同时又需阻力低、结构简单且运行可靠。(5)研究了不同煤焦还原NO的动力学,将得到的动力学参数用于分解炉模拟计算。在分解炉计算机辅助试验平台上了模拟了TTF三喷腾型分解炉采用三次风分风措施降低氮氧化物排放浓度的研究。水泥厂实际检测数据显示,三次风分风方式可降低氮氧化物排放10~36%。更多还原

【Abstract】 The most advanced technology in modern cement industry so far is the precalcining technique in the world. Although China’s cement industry has achieved great development in recent years, there still exists a gap with the international most advanced level in heat consumption, power consumption, pollutants such as NOx emission etc. The optimization of cement precalcining system is one of the main approaches to realize energy saving, consumption reducing, and pollutant emission decreasing. As a result, research on the technology of energy saving and emission reduction of the precalcining system in cement industry and applying these technologies in practical projects are of practical significance for the cement industry to realize low-carbon economy and harmonious development with resources and environment.Based on the laboratory experiments, theoretical analysis, computer simulation and practical measurement in cement industry, environmentally-friendly cement precalcining system were studied thoroughly. Major contents include:(1) The dispersing performance of splash boxes with various structures, with dispersion plates with different angle and insertion depth and so on was carried out using the experimental platform of splash box. From the mathematical analysis results, the optimum dispersion can be obtained for the material when the dispersion plate has an angle measuring 5 degrees and the insertion depth of 200 mm. Engineering application confirms that preheater exit gas temperature is 15~20oC lower after the optimization of splash box.(2) The parameters for the turbulence model in the computational fluid dynamics were corrected with the data from cold condition test of cyclone. The flow field, heat exchange efficiency and separation efficiency of the six-stage preheater system developed by Tianjin Cement Industry Design and Research Institute Company Limited (TCDRI) before and after optimization were simulated and analyzed with Reynolds stress model (RSM) and discrete phase model (DPM). The computational results indicate that the pressure loss of the optimized six-stage preheater system drops by 13.8% when compared with that of the previous one, while the heat exchange efficiency decreases by 1.7%, indicating that the optimized six-stage preheater system exhibits a better energy-saving result.(3) Based on the theoretical analysis and derivation, a formula to calculate the pressure loss of a cyclone used for cement production has been put into forward. This paper presents concepts of effective energy and non-effective energy, dictating the energy utilization efficiency for cyclones. Both reducing the pressure loss and raising utilization efficiency of effective energy should be considered for the cyclone development.(4) The correlation between the combustion characteristics of fuel and the design of calciner was studied with the lab tests and CFD modeling. The requirement for a reasonable and efficient calciner is to guarantee the ignition and complete combustion for various fuels and a high burnout rate. Meanwhile low pressure loss, simple structure and high operation reliability should be compatibly considered for the calciner.(5) The kinetic study of NO reduction over coal chars was carried out and kinetic parameters obtained were introduced into the numerical simulation in the calciner. The NOx emission concentration for tri-spouted TTF calciner, introducing the staged tertiary air to reduce NOx emission, was simulated through the computer auxiliary test platform for calciner. The practical measuring data in cement plants show that the method of staged tertiary air can decrease NOx emission by 10~36%.更多还原