C-H-O Systems in the Presence of an Iron Catalyst

Abstract

Experiments were conducted to measure carbon deposition from gas mixtures containing CO, C02, H2, H20, and CH4. The temperature was 823 K and the pressure 1 atm. An iron catalyst was employed. It was concluded that two conditions have to be satisfied before carbon deposition occurs, viz. the thermodynamics must be favorable for carbon deposition and the gas phase composition must not lie in ranges where the iron oxidizes or carbides as neither of these appear to be a catalyst for carbon deposition reactions. The formation of an oxide or carbide may be treated as a restraint to the attainment of reaction equilibria in the carbon deposition process.It is not uncommon to find high-temperature gas mixtures containing CO, C02, H2, H20, and CH4 in contact with iron or steel. Carbon deposition may occur and simultaneous

Understanding the variability in freshwater radiocarbon reservoir offsets: a cautionary tale

“…These and CO 2 gas from water samples were then graphitised in the presence of an iron catalyst at 560 C for a maximum of 4 h according to the BoscheManning Hydrogen Reduction Method (Manning and Reid, 1977;Vogel et al, 1984) and 14 C, 13 C and 12 C were analysed on a 0.5 MV National Electrostatics Corporation compact accelerator. The sample 14 C/ 12 C ratio was background corrected and normalised to the HOXII standard (SRM 4990C; National Institute of Standards and Technology).…”

Optimization of the Graphitization Process at Age-1

“…Unfortunately, these articles are not focused directly on carbon production. Useful information for graphitization processes can be found in the literature (Pichler and Merkel 1949;Walker et al 1959a,b;Manning and Reid 1977;Sacco and Reid 1979;Liaw and Davis 2000;van der Laan and Beenackers 2000;Gudenau et al 2005;Oeters et al 2009). …”

Illumination of a Black Box: Analysis of Gas Composition During Graphite Target Preparation

“…The methods currently in use at 14C AMS labs around the world include reduction with H2 over a transition metal catalyst (Vogel, Southon & Nelson 1987), and reduction with Zn over a transition metal catalyst (Slota et al 1987). The reactions involved in these two methods have been well studied and reviewed (Boudouard 1901;Manning & Reid 1977;Turkdogan & Vinters 1974;Jull et al 1986;Slota et al 1987;Vogel, Nelson & Southon 1987); important reactions are listed in Table 1. Most studies of these reactions were conducted at constant pressures (Boudouard 1901;Manning & Reid 1977;Turkdogan & Vinters 1974), usually around one atmosphere, conditions that do not represent those used during the formation of AMS targets.…”