Study on Hydrogen Fluoride at High Temperature Detection Method with Temperature Correction Based on Laser Technology.

ABSTRACT

Hydrogen fluoride(HF) is one of the important character gases for fault diagnosis of gas insulation switch (GIS) in the system of substation equipment. The high-accuracy, fast- response and real-time detection method of HF is a focus in industrial and environmental fields. In this research, the HF detection experiment system was set up at first based on laser absorption spectroscopy technology combined with anti-corrosion multiple reflection cell made by monel steel. Moreover, the laser absorption spectral characteristics of HF at different temperature were analyzed, then the coefficient partition function curve and absorption linestrength curve according to the distribution function coefficient in HITRAN database were studied. As the most important work, the concentration inversion algorithm was designed here with HF character spectrum analysis and temperature parameter correction method for accurate concentration inversion after the basic study. At last, the continuous experimental results were obtained by HF sample gases of different concentration considerating the temperature characteristic of the multiple reflection cell. When the multiple reflection cell was heat and stay stably, the biggest detection error of concentration inversion was 5.33% and 5.87% at 313 and 323 K respectively without temperature correction, and that was 1.20% and 1.47% respectively after temperature correction. By continuous detection and culculation, the detection limit is 8.7×10-5 mmol·mol-1 at 323 K which is a little higher than 6.3×10-5 mmol·mol-1 at 290 K(20 m optical length). Although the detection error with temperature correction at high temperature was higher than it at room temperature, the results show that it was lower than that without correction at the same temperature. It was verified that the this spectrum detection method and concentration inversion algorithm works stably and reliably, so this technology could realize HF real-time monitoring demand in chemical production field and it will provide the effective technical support in gas emission regulation in safety and environment protection for our country.