实用化微型近红外光谱分析仪的设计与性能测试

Design and Performance Test of Practical Near Infrared Micro-Spectrometer

近红外光谱分析作为石油勘探过程中油品成分鉴别的一种重要手段,多年来引起人们的广泛关注和深入研究。针对石油勘探过程中油藏井温度高、空间局促等苛刻环境条件,研制了一种能够在高温环境中连续稳定工作的实用化微型近红外光谱分析仪,其体积为154mm×66.5mm×38mm。该微型近红外光谱分析仪采用凹面光栅作为分光元件,针对油气特征波段进行理论计算和Zemax软件仿真,设计出通量高、杂散光少、成像优质的全息凹面光栅。探测器选用Hamamatsu公司二级半导体制冷线阵电荷耦合器件(CCD),通过合理的光路设计和紧凑的结构布局,实现了在70℃的高温环境下稳定工作。通过标定及相关性能测试,结果表明:该微型近红外光谱分析仪光谱范围达到1550~1890nm,分辨率优于4.8nm,波长准确性±1.1nm,信噪比1202…1;利用该光谱分析仪对0#柴油和水的吸光度进行了应用实验,结果充分证明该系统的实用化水平。

In recent years, near infrared （NIR） spectroscopic analysis has attracted wide attention and it has been researched deeply as an important method of the identification of oil components in the process of petroleum exploration. The environmental conditions in the process of petroleum exploration are severe because of high temperature and cramped space in reservoirs. In view of the above technical problems, this paper develops a practical NIR micro spectrometer with the volume of 154 mm×66.5 mm × 38 mm, which can continuously and stably work in high temperature condition. The NIR micro spectrometer selects concave grating as splitting element. The holographic concave grating with high throughput, few stray light and high quality imaging is designed by theoretical calculation and Zemax software simulation for characteristic band of oil gas. The detector adopts two stage semiconductor refrigeration linear charge-coupled device （CCD） of Hamamatsu. Through reasonable optical design and compact structure layout, it can stably work in high temperature condition of 70 ℃. Then we calibrate and test performance of the spectrometer. The results show that spectral region of the NIR micro spectrometer ranges from 1550 nm to 1890 nm, the resolution is better than 4.8 nm, the accuracy of wavelength is ±1.1 nm, and the signal-to-noise ratio is 120211. Finally, we conduct the application experiment of absorbance for 0 # diesel oil and water, which fully demonstrates the practical level of the system.