Measurement of methane Ccontent in upgraded biogas using pulse-echo ultrasound

Abstract

In this paper we present an ultrasonic pulseecho technique for estimating the methane (CH 4 ) content in binary mixtures of CH 4 and carbon dioxide (CO 2 ). The method is based on parametric estimation of phase velocity and frequency dependent attenuation in combination with Partial Least-Squares Regression (PLSR). The technique is verified using experiments on mixtures with a volume fraction of CO 2 in the range of 0 % -10 %. The experiments show that the CH 4 content can be accurately estimated with high repeatability.

Combined physical and statistical modeling of laser induced ultrasound signals from thin light absorbing films

“…This interval was simulated based on the assumption of an uncertainty in the voltage measurement of 5% (of the maximum measured voltage). The details of the simulation are described in [17]. This is to test how sensitive the multivariate calibration is to experimental noise, and it is clear from these simulation that the estimation is very robust.…”