Maturity-related variation in the bulk-transformation kinetics of a suite of compositionally related New Zealand coals

A novel procedure to detect low molecular weight compounds released by alkaline ester cleavage from low maturity coals to assess its feedstock potential for deep microbial life

“…The North and South Island of New Zealand are home to coals covering a broad maturity range of almost continuous maturity (R 0 : 0.25 -3.0%) from Cretaceous to Tertiary age in freshly exposed coal facies, coal mines and drill cores (Figure 1) forming the so called New Zealand Coal Band (Suggate, 2000;Killops et al, 2002;Sykes and Snowdon, 2002). Therefore, the New Zealand Coal Band provides one of the best maturity rank series in the world to examine natural maturation processes in coals.…”

“…To improve the understanding of the molecular composition of kerogen various analytical techniques were used such as nuclear magnetic resonance spectroscopy (NMR) (Derbyshire et al, 1989;Burgess and Schobert, 1998;Suggate and Dickinson, 2004;Werner-Zwanziger et al, 2005), infrared spectroscopy (IR) (Robin, 1975;Rullkötter and Michaelis, 1990;Lis et al, 2005) pyrolysis gas chromatography-mass spectrometry (Pyrolysis GC-MS) (Larter and Douglas, 1982;Horsfield and Larter, 1993;Khaddor et al, 2002;Killops et al, 2002;Sykes and Snowdon, 2002) and selective chemical degradation reactions (Schouten et al, 1993;Schaeffer et al, 1995;Höld et al, 1998;Putschew et al, 1998;Schaeffer-Reiss et al, 1998). These powerful analytic tools provided various information about the compositional structure of kerogen and its maturation history (Vandenbroucke and Largeau, 2007).…”

Artificial maturation of a high volatile bituminous coal from Asturias (NW Spain) in a confined pyrolysis system

“…In general, the kinetic models used for maturation assessment assume that the reactions are controlled by time and temperature but it ignores the effect of pressure on endothermic volume expansion reactions, e.g., maturation and hydrocarbon generation [20]. In addition, the modeling of the petroleum generation from coals presents some additional problems to those found with marine source rocks, apparently related to structural rearrangements of the macromolecular network [21]. Therefore, the structural rearrangements have significant implications for the kinetic modeling of the petroleum generation from coals [22,23,21], and they may be taken into account in the results.…”

“…In addition, the modeling of the petroleum generation from coals presents some additional problems to those found with marine source rocks, apparently related to structural rearrangements of the macromolecular network [21]. Therefore, the structural rearrangements have significant implications for the kinetic modeling of the petroleum generation from coals [22,23,21], and they may be taken into account in the results.…”

“…According to Schenk and Horsfield [22], and Killops et al [21], for maturation of solid residues of the same composition, the aromatisation reactions will have the greatest influence on gas generation and the transformation and degradation of aliphatics and polars (Fig. 4).…”