Photonics Laboratory, Munich University of Applied Sciences, Lothstrasse 34, 80335 Munich, Germany.
MAN Energy Solutions SE, Werftstrasse 17, 94469 Deggendorf, Germany.
Sensors (Basel). 2019 Dec 12;19(24):5476. doi: 10.3390/s19245476.
A low-drift fiber-optic sensor system, consisting of 24 regenerated fiber Bragg gratings (RFBG), equally distributed over a length of 2.3 m, is presented here. The sensor system can monitor spatially extended temperature profiles with a time resolution of 1 Hz at temperatures of up to 500 °C. The system is intended to be used in chemical reactors for both the control of the production ramp-up, where a fast time response is needed, as well as for production surveillance, where low sensor drifts over several years are required. The fiber-optic sensor system was installed in a pilot test reactor and was exposed to a constant temperature profile, with temperatures in the range of 150-500 °C for more than two years. During this period, the temperature profile was measured every three to five months and the fiber-optic temperature data were compared with data from a three-point thermocouple array and a calibrated single-point thermocouple. A very good agreement between all temperature measurements was found. The drift rates of the 24 RFBG sensor elements were determined by comparing the Bragg wavelengths at a precisely defined reference temperature near room temperature before and after the two-year deployment. They were found to be in the range of 0.0 K/a to 2.3 K/a, with an average value of 1.0 K/a. These low drift rates were achieved by a dedicated temperature treatment of the RFBGs during fabrication. Here, the demonstrated robustness, accuracy, and low drift characteristics show the potential of fiber-optic sensors for future industrial applications.
一种低漂移光纤传感器系统，由 24 个再生光纤布拉格光栅（RFBG）组成，均匀分布在 2.3 米的长度上，这里介绍一下。该传感器系统可以在高达 500°C 的温度下以 1Hz 的时间分辨率监测空间扩展的温度分布。该系统旨在用于化学反应器中，既用于生产爬坡的控制，需要快速的时间响应，也用于生产监测，需要多年的低传感器漂移。光纤传感器系统安装在一个中试规模的反应堆中，并暴露在恒定的温度分布中，温度范围为 150-500°C，超过两年。在此期间，每隔三到五个月测量一次温度分布，并将光纤温度数据与三点热电偶阵列和校准的单点热电偶的数据进行比较。所有温度测量之间都发现非常好的一致性。通过在两年部署前后在接近室温的精确定义的参考温度下比较布拉格波长，确定了 24 个 RFBG 传感器元件的漂移率。它们的范围在 0.0 K/a 到 2.3 K/a 之间，平均值为 1.0 K/a。通过在制造过程中对 RFBG 进行专门的温度处理，实现了这种低漂移率。这里，展示的鲁棒性、准确性和低漂移特性表明光纤传感器具有未来工业应用的潜力。
