Abstract

This paper presents the design and application of a near-infrared laser absorption-based sensor for methane measurements during anaerobic digestion using an optical probe inserted into an anaerobic tank reactor. The wavelength of the laser was scanned across the absorption lines of methane near 1.65 µm to provide the real-time concentration. A probe was designed for optical measurement. This technique was validated by measuring methane in the laboratory and anaerobic digestion tank reactor. A set of reference values spanning from 30 to 52%, covering the typical concentrations during anaerobic digestion, were measured to validate the reliability of the system. The spectrometrically derived methane concentrations showed high consistency with the reference values, and an R² of 0.999 revealed that the system was reliable. In addition, the detection limit was estimated by the uncertainty of the intercept to be 0.27% with an accuracy of 0.1% and a temporal resolution of 1 s.

摘要

本文介绍了一种基于近红外激光吸收的传感器的设计和应用，该传感器使用插入厌氧罐反应器的光学探针来测量厌氧消化过程中的甲烷。激光波长扫描 1.65 µm 附近的甲烷吸收线，以提供实时浓度。探针被设计用于光学测量。通过在实验室和厌氧消化罐反应器中测量甲烷来验证该技术。测量了一组从 30% 到 52% 的参考值，涵盖了厌氧消化过程中的典型浓度，以验证系统的可靠性。光谱法得出的甲烷浓度与参考值高度一致，R ²0.999表明系统是可靠的。此外，通过截距不确定度估计检测限为0.27%，准确度为0.1%，时间分辨率为1 s。