【作者】 孙志春；

【导师】 杨勇平；

【作者基本信息】 华北电力大学（北京） ， 动力工程及工程热物理， 2010， 博士

【摘要】 50%以上的火力发电机组烟气湿法脱硫系统设置气气换热器(GGH)。实际运行中,GGH堵塞引起压差增大,严重时导致增压风机失速、锅炉跳闸,影响机组运行的安全性、经济性和环保效益。为了系统地解决GGH堵塞问题,本课题组在GGH堵塞机理、GGH结垢成分、除雾器性能、JBR控制特性等方面进行了深入研究。首先对GGH不同端的垢成分进行元素分析和物相分析,发现GGH结垢物主要来源于净烟气所携带的石膏浆液。通过对台山和定州二电厂整个脱硫系统速度场的数值模拟计算和实测验证,发现除雾器前速度场分布不均匀,烟气流速偏离了除雾器的最佳除雾效率区,导致烟气携带的石灰石浆液进入GGH,造成GGH堵塞；通过实验研究,得出除雾器的各个参数如板型、板间距、烟气流速等对除雾效率的影响关系如下：折形板及弧形板的高效除雾烟气流速范围为4m/s-8m/s;烟气流速大于8m／s后,除雾器发生二次携带导致效率急剧下降；两级布置方式弧-折26-20除雾器叶片组合平均除雾效率比台山电厂原有板型提高约8%,效果最为理想；三级除雾器组合与两级除雾器组合相比除雾效果并没有明显提高。除雾器的数值模拟表明：随着液滴直径的增大,除雾效率迅速增大；折线板除雾器适用于大液滴的分离；弧形板除雾器适用于小液滴的脱除；除雾器对粒径在20微米以下的液滴脱除效率较低。JBR反应器实验表明：随JBR运行液位增加,小液滴生成量明显减少；在液位下增加网栅可以有效降低小液滴浓度；鉴于实际运行中JBR液位主要以125mm为主,建议网栅的最佳安装位置是距离喷射孔50mm处。在机理研究的基础上,本课题组开发了微小液滴在线测试技术、脱硫塔小液滴控制技术、除雾器板型与除雾效率耦合技术、GGH换热元件清洗技术等关键技术,系统性地提出GGH堵塞解决方案,并且在台山、定州等多个大型火力发电厂进行了工程实践应用,取得了良好效果。更多还原

【Abstract】 More than 50% of wet flue gas desulphurization system thermal power generating units set gas gas heater (GGH). In practical operation, GGH plug causes pressure increasing, leading to serious boosting fan stall, boiler trip; and affecting the safety of plant operation, economy and environmental benefits. For solving the congestion problems of GGH, the blocking mechanism of GGH, GGH scale composition, mist eliminator performance, the jet bubble reacter (JBR) control features and so on have been studied.First of all, it has been found that GGH scale is derived from the gypsum slurry carried by the net flue gas by analyzing phase and elemental of the GGH different side of the scale composition. Based on the power plants in Taishan and Dingzhou velocity field throughout the desulfurization system numerical simulation and experimental verification, it has been found that the velocity field before demister uneven distribution of flue gas velocity deviation from the best defogging efficiency demister area limestone slurry flue gas carried by leading to the increas GGH jam.The experiment of various parameters demister such as plate type, plate spacing, gas flow rate, effects on the efficiency demister has been performed, with arc-shaped plate and folded plate flue gas flow rate range of high defogging 4m/s～8m/s. The second brought in demister accurs when the fluegas flow rate is higher than 8m/s, leading the efficiency to a rapid decline. Two layout arc-Pack 26-20 combinations of blade Taishan power plant is more efficient than the average fog removing the original plate by about 8%; and three combinations with two demister combination have no significant improvement. Numerical simulation of demister shows that as the droplet diameter increases, the defogging efficiency increases rapidly. Folded plate demister fits for the separation of large droplets. Arc-shaped plate demister fits for the removal of tiny droplets. Droplets on the particle size of 20 microns or less are in the low efficiency of removal. JBR reactor experiment shows that:with the JBR run liquid level increases, the generation of small droplets remarkablely reduces; and the concentration of small droplets can be reduced by increasing the level of grid. In view of the actual operation of JBR 125mm, it’s concluded that the best grid installation location is 50mm from the jet orifice department. On the basis of the mechanism, a technology of tiny droplets online test, desulfurization tower tiny droplets controling technology, demister plate coupled with the defogging efficiency technology, GGH heat exchanger cleaning technology and other key technology components have been developed. GGH plug of solution has been put forward, and the application in Taishan, Dingzhou and other large-scale thermal power plant engineering has got good results.更多还原