2026-09-21T13:25:40Zhttps://repository.unam.edu.na/server/oai/request

oai:repository.unam.edu.na:11070/42752026-07-04T22:01:10Zcom_11070_3408com_11070_3311com_11070_3304col_11070_642

Chiguvare, Zivayi Shilongo, Rosamunde P. 2026-06-24T12:08:20Z 2026-06-24T12:08:20Z 2025 http://hdl.handle.net/11070/4275 A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Renewable energy Hydrogen purity assessment is a critical concern in energy applications, especially in fields involving hydrogen injection into natural gas pipelines and fuel cell research. This study addresses the limitations of current hydrogen measurement techniques by developing a novel hydrogen spectrometer (𝐻2-Spectrometer) based on direct Tunable Diode Laser Absorption Spectroscopy (d-TDLAS). The goal is to establish a traceable and accurate methodology for hydrogen purity and concentration measurement without relying on calibration gases. The main objective of this research is to develop and evaluate the performance of the 𝐻2-Spectrometer, specifically investigating its suitability for measuring hydrogen purity and hydrogen concentration in methane hydrogen mixtures. The study also aims to support hydrogen injection into natural gas pipelines by providing precise hydrogen concentration measurements. An experimental design was employed, utilizing the 𝐻2-Spectrometer to measure hydrogen line intensity and concentration. The measurements were taken for 99.999% pure hydrogen and hydrogen-methane gas mixtures to test the spectrometer’s accuracy and reliability. The obtained data were compared against reference values from the HITRAN database and the certificate from the reference gas mix to evaluate performance. The findings revealed that the 𝐻2-Spectrometer demonstrated a significantly lower uncertainty of 1.6% in hydrogen line intensity measurements, compared to the 10% uncertainty reported in the HITRAN database. The measured line intensity obtained was 3.22 × 10−26 cm/molecule, which is slightly higher than the HITRAN value of 3.189 × 10−26 cm/molecule. In terms of hydrogen concentration, the spectrometer achieved an average mole fraction of 0.858 with a 1% uncertainty, closely aligning with the expected value of 0.900 as per the certificate from the reference gas mix with a 2% uncertainty. The 𝐻2 Spectrometer proved to be highly accurate and reliable, with potential applications in hydrogen quality control from electrolysis, fuel cell research, process control, and environmental monitoring. Its ability to provide traceable and precise measurements makes it a valuable tool for hydrogen-related research, optimizing system performance and ensuring compliance with regulatory standards en University of Namibia Direct Tunable Diode Laser Absorption Spectroscopy Hydrogen spectrometer Purity assessment Traceable Infrared Laser Spectrometric Amount Fraction Measurement (TILSAM) Namibia University of Namibia Hydrogen purity assessment using laser absorption Spectroscopy Thesisopen.access