300MW机组除氧器水位检测控制系统教程.doc

300MW机组除氧器水位检测控制系统 毕业设计（论文）  PAGE III 摘 要 除氧器的水箱是为保证锅炉有一定的给水储备而设置的，其容量一般不应小于锅炉额定负荷下连续运行15~20min所需的给水量。除氧器水位过低，储水量不足有可能危及锅炉的安全运行，此外还有可能造成给水泵入口汽化。除氧器水位过高，则妨碍除氧器除氧。因此，除氧器水位应维持在容许范围内。由于热力循环中不断有工质损失，因此要向热力系统不断补充水。补充水来自化学水处理装置。补充水可直接进入除氧器，也可以送凝汽器进行真空除氧后在送至除氧器。 火力发电厂的热力除氧器利用汽轮机的抽气加热锅炉给水，使得锅炉的给水达到该压力下相应的饱和温度，以除去溶于水中的氧气等气体，防止锅炉、汽轮机和管道等热力设备遭到腐蚀，另一方面除氧器是汽水直接接触式的加热器，它是给水加热系统中的一环，利用汽轮机的抽气加热锅炉给水，可以提高电厂效率，节省燃料。除氧器是电厂重要的辅助设备之一，是电厂热力系统中不可缺少的环节。所以说除氧器的水位控制对锅炉的安全稳定运行至关重要。 关键字 除氧器，水位调节，单冲量，串级三冲量  PAGE IV Abstract Deaerator water tank is to ensure that the boiler has a water reserve and settings, its capacity should generally not be less than rated boiler load continuous operation for 15 ~ 20min to water.?Deaerator water level too low, insufficient storage capacity may endanger the safe operation of the boiler, in addition to may resulting in water pump inlet vaporization. Deaeratorwater level is too high, obstructs the deaerating. Therefore, the deaerator water level should be maintained within ?the ?allowable range. The?thermodynamic cycle of ??constantly?refrigerantloss,?therefore to thermal system continuously add?water. The chemical water treatment from water supplement device. Water can be directly added ?to the deaerator, also can send condenser vacuum deaerator?after sent to the deaerator. Thermal power plant deaerator use steam turbine pumping gas heating boiler, the boiler feed water the pressure corresponding saturation temperature is reached, to remove dissolved in the water of oxygen and other gases, to prevent the boiler, turbine and pipeline by thermal equipment corrosion and the other side surface of the deaerator is steam water direct contact of the heater, it is water heating system in a ring, the use of steam turbine pumping gas heating boiler feedwater, can improve the efficiency of power plants and fuel saving.?The deaerator?is one of the important auxiliary?equipment of power plant,?is an indispensable?link in the?power plant thermal system.?So the deaerat