摘 要:石灰石/石膏湿法烟气脱硫技术是火电厂二氧化硫减排最有效、最成熟的方法，其主要优点是：适用的煤种范围广、脱硫效率高、吸收剂利用率高（可大于90％）、设备运转率高（可达90％以上）、工作的可靠性高、脱硫剂石灰石来源丰富且廉价。
该技术工艺流程：锅炉引风机排出的原烟气由增压风机导入脱硫系统，通过GGH（气体加热器）进行热交换后烟气进入吸收塔。在吸收塔内，原烟气自下而上通过塔身，遇喷淋系统喷出的雾状石灰石浆液逆流混合，脱硫后的净烟气经喷淋系统上部的除雾器除去烟气所携带的雾滴后排除吸收塔进入GGH，经过GGH换热升温后经烟囱排出。吸收塔SO2的浆液落入吸收塔底部反应槽，通过脱硫循环泵与补充的石灰石浆液再次从吸收塔上的喷淋系统喷出，洗涤烟气中的SO2。混合浆液在反应槽内由外置的氧化风机供给空气使亚硫酸根氧化成石膏。
本文旨在通过对300MW级火电机组的脱硫处理工艺设计，了解并逐渐掌握主要的湿法脱硫工艺设计技术，获得足够的工程设计经验。
本文对300MW级火电机组石灰石/石膏湿法脱硫处理技术进行了设计规划，完成了烟气和脱硫剂的物料平衡计算，按照应达到的脱硫率要求，计算需要投入消耗的原料和产出的物料之间的关系；进行系统设备的主要性能参数设定，完成系统设备的选型，着重分析了石灰石，石膏湿法烟气脱硫(FGD)系统中的吸收塔、浆液循环泵、烟气换热器、增压风机、除雾器等运行情况；进行相关辅助系统的设计计算，完成相关的物料平衡设计，完成脱硫系统工艺设计。本文还对脱硫设计过程中的一些关键问题(如吸收塔浆液循环量与烟气含硫量的关系等)进行了探讨，为最终掌握石灰石/石膏法脱硫处理技术、优化设计以及主要设备国产化打下基础。
关键词：脱硫，吸收塔，石灰石，石膏，脱硫率
Abstract:Limestone-gypsum FGD technology is the most effective and ripest method of sulfur dioxide emission reduction in thermal power generating plant. The main advantages of the technology are as follows. First, it can applies to a wide range of coal. Second, the efficiency of desulfurization is high. Third, it can be also take full advantage of absorbent( ＞90%). Fourthly, the equipment operating rate is effective. Finally, the origin of limestone is rich and low price.
The common process of the technology is that, the gas from boiler will be guide into gas desulfurization system by blower fan, before the tower, the gas through the GGH for heat exchange. During the tower, the gas flow from bottom to top, and mix with the limestone grout which from spray system. The net flu gas will remove droplets through defrost and then enter into the GGH, after heat exchanging discharge the gas from stack. The sulfur dioxide is absorbed through a series of chemical reactions will finally generate the gypsum.
In my thesis, by means of designing the FGD disposal process for 300MW thermal power generating units, I have realized and mastered the wet desulfurization process design technology gradually, and obtained enough experience of engineering design.
Based on planning the limestone-gypsum FGD technology for 300MW thermal power generating units, I have calculated the mass balance of the flue gas and desulphurizer as per the required desulfurization rate, calculate the relationship between consumed materials and produced mass, setup the main performance parameters of system devices, completed selection of the system equipment, calculated the relevant assistant system equipped for desulfurization, finished related mass balance design, and fulfilled overall FGD system process design. What’s more, I have further discussed about the key sections in desulfurization design process, such as the relation between absorber slurry recirculation flow and sulfur contents in gas, to establish the foundation of ultimately mastering limestone-gypsum FGD disposal optimized technology and nationalize FGD major equipment.
Keyword: Desulperization, Absorber, Limestone, Gypsum, Desulperized rate
