Investigation of the combustion of methane using CuO for radiocarbon dating
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Date
2019-09-15
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
For the combustion of methane (CH4) gas to carbon dioxide (CO2), we investigated the use of copper oxide (CuO) as the source of oxygen, using our type 2 Micro Conventional Furnaces (MCF-II), traditionally used for the reduction of CO2 to graphite for AMS measurement Yang and Smith, 2017 [1]. Experiments showed that both graphite and CH4 can be oxidised to CO2 rapidly at a temperature at 780 °C. The reaction is complete within just a few minutes for graphite and within about one hour for CH4 gas. However, this method is only suitable for combustion of CH4 when the concentration >3% due to the small internal volume of MCF-II. To combust gases of lower CH4 concentration, we installed a gas circulation loop with additional components including 1) a novel, newly designed MCF-III with a dual tube furnace for heating 6 mm OD quartz tubes up to 850 °C; 2) a gas circulating unit comprising a miniature diaphragm pump and flow meter along with a needle valve for adjusting gas flow rate; 3) differently sized gas storage tubes and bags, permitting optimisation of the carbon sample size; 4) a water trap and miniature CO2 gas traps −65 °C and −150 °C respectively Yang et al., 2013 [2]. This system is also suitable for collecting CO2 from air at atmospheric concentrations. It also has the flexibility to assemble a specific gas trapping/combustion system to suit the composition of individual gas samples. We report on the early performance with some samples and our evaluation of the cross contamination between CO2 and CH4 based AMS measurement of a set of mixing gas CO2/CH4/N2 samples. Crown Copyright © 2018 Published by Elsevier B.V.
Description
Keywords
Accelerators, Mass spectroscopy, Carbon 14, Methane, Carbon dioxide, Combustion, Bosch process, Copper oxides, ANSTO, Australian organizations, Stable isotopes, Graphite, Temperature range
Citation
Yang, B., & Smith, A. M. (2019). Investigation of the combustion of methane using CuO for radiocarbon dating. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 455, 165-170. doi:10.1016/j.nimb.2018.12.018