TGA基点漂移量的测试与分析  

Measuring-testing and Analysis of TGA Base-point Drift Magnitude

作　　者：余娜[1] 傅培舫[1] 周怀春[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,湖北武汉430074

出　　处：《热能动力工程》2006年第6期618-622,共5页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金资助项目(50576025)

摘　　要：基点漂移量与煤的低温吸氧量属同一数量级，严重影响实验结果的精度．实验中发现精度很高的STA409C热重分析仪的基点漂移量选3％-7％，绝对量为0．2～0．5mg。通过理论计算和TGA空白实验的方法发现，影响STA409C基点漂移的主要因素为升温引起的与重力方向相同的浮力增量、气流向上流动引起的绕流升力和粘性牵引力；通过选择合适的气体流量、降低升温速率、改变炉内气体的组分以减小密度、增加气体的发射和吸收能力均有利于减少基点漂移量。当基点漂移量为7％时，活化能的偏差为0．28％。The base-point drift magnitude pertains to the same order of magnitude as the low-temperature oxygen absorption quantity of coal and can seriously affect the accuracy of experimental results. It has been found during experiments that the base-point drift magnitude of a high-precision STA 409C thermogravimetric analyzer could reach 3% to 7% with its absolute value being 0.2 to 0.5 mg. Through a theoretical calculation and the use of TGA blank experiment method, the main factors affecting STA 409C base-point drift magnitude are identified as the temperature-rise caused buoyancy increment assuming the same direction as gravity, the lifting forces of streaming and a viscid tractive force sparked by an upward gas flow. To choose an appropriate gas flow rate, slow down the speed of temperature rise, change the constituent of gases inside the furnace to decrease density and enhance the emission and absorption capacity of gases can all contribute to decreasing the base-point drift magnitude. When the base-point drift magnitude reaches 7%, the deviation of activation energy will be 0.28%.

关 键 词：TGA 基点漂移 浮力变化量 升力变化量 

分 类 号：TK16[动力工程及工程热物理—热能工程]