Photographic Analysis and Optical Diagnosis of Kilowatt Microwave Plasma Torch with Air Carrier Gas

The spatiotemporal motion characteristics of the kilowatt argon microwave plasma torch with the air carrier gas(kW-AC-ArMPT)and the behavior of the plasma filaments are investigated with a digital single-lens reflex(SLR)camera and a high-speed camera.Along with the introduction of the air,both the volume of the central channel and the rotational frequency of the plasma filament are increased.Besides,the excitation temperature(Texc),rotational temperature(Trot),and density of electron number(ne)of the kW-AC-ArMPT are measured with optical diagnosis.It is clearly shown that the introduction of air contributed to the rise of Trot and ne of the plasma,which is beneficial to improving the analytical performance of the plasma.Then the detection limits of some heavy metal elements are measured by kW-AC-ArMPT,which are in the ppb range.The experimental results show that the kW-ArMPT has a high tolerance to air injection at least 1.0 L/min,which allows the direct extraction of air from the environment for analysis and therefore has the potential for online and in-situ detection of ambient air quality and industrial exhaust gases.

提高锅炉等离子体火炬燃弧稳定性的参数调整方法研究

等离子体点火(也称等离子体火炬)已广泛应用于火力发电厂的锅炉点火,但由于系统复杂,工作环境恶劣,运行一段时间后容易出现起弧困难、频繁熄弧等问题。以某次点火过程中出现频繁熄弧问题为切入点,对等离子体火炬熄弧现象的数据进行了统计分析,研究提高燃弧稳定性的方法。结合简易电弧理论模型和试验数据,明确了电弧电压与轴向气压的强相关性,提出了定量评价燃弧质量的统计指标,并结合历史数据和正常设备数据对熄弧现象进行对比分析。研究发现,此次点火过程中火炬状态发生变化,在轴向气压未调整的情况下,出现电弧电压超过额定值的现象,导致了电源电压裕量不足,进而降低了燃弧稳定性。利用电弧电压与轴向气压的强相关性,通过拟合其线性关系可对电弧电压定量调整,调整后实现稳定燃弧。火炬的状态存在动态变化的现象,运行参数宜根据当前电弧特性动态调整,避免电压过高引发熄弧。研究结果可以为相关设备故障分析、提高点火装置运行管理水平和相关技术改造提供理论和方法参考。

小功率空气冷却ICP-AES研究(III)——IIIA,IB和IIB族元素在空气冷却ICP中的行为

用商品仪器,在与全氩电感耦合等离子体(ICP)类似的条件下,测定了ⅢA,ⅠB和ⅡB族元素的77条谱线在小功率空气冷却ICP中的信背比和检测限,并测绘了其中的30条杰出谱线和9种常见共存元素的光谱重叠扫描图,估计了可能存在的光谱干扰。