Stone Dust Looping for Ventilation Air Methane Abatement: A 1 m³/s Pilot-Scale Study

Abstract

Ventilation air methane (VAM) emissions are a significant contributor to fugitive greenhouse gas emissions at underground coal mines. The stone dust looping (SDL) process is a novel technology developed at The University of Newcastle, Australia, for VAM abatement. The SDL process is a cyclic process in which calcium oxide (CaO) is first obtained from the calcination of limestone (CaCO 3 ). CaO is then used to simultaneously oxidize VAM (methane concentrations of 0.1− 1 vol % in air) and capture carbon dioxide (CO 2 ) produced to form CaCO 3 . The two cycles can be performed in a single reactor, or the process can be performed continuously in dual interconnected reactors. Preliminary experiments on the SDL process have previously been performed at laboratory scale. In this study, further laboratory-scale studies were conducted in conjunction with pilot-scale SDL investigations in a single 1 m 3 /s fluidized bed reactor. The effect of inventory size (1−2 tonnes of CaCO 3 ), operating temperature (565−700 °C), and flow rate (1−1.7 m 3 /s) on methane conversion was investigated. At temperatures of 600 °C and above, >99.5% methane conversion was achieved for all inventory sizes and flow rates examined. At temperatures of 565 and 575 °C, 41 and 70% methane conversions were achieved, respectively. VAM fluctuation experiments were performed, and it was shown that a fluid bed can act as a thermal mass to reduce fluctuations in the bed temperature as the VAM concentration changes.

Methane separation from diluted mixtures by fixed bed adsorption using MOFs: Model validation and parametric studies

“…The main features of the VAM emissions are their low methane concentration (0.1-1%) and high flow rates (up to 600 m 3 /s), a direct upgrading of these streams being strongly hindered [6]. The most feasible and environmentally friendly solution is to pre-concentrate methane in these streams.…”

Will It Be Possible to Put into Practice the Mitigation of Ventilation Air Methane Emissions? Review on the State-of-the-Art and Emerging Materials and Technologies

“…It was shown that the measured values were different between the examined objects, but also depended on the currently conducted mining works (see Table 1). As reported by other sources, the VAM flow rate can achieve even 600 m 3 /s [19,20] and daily dust loading can reach 232 kg [21]. It should be considered that all mentioned parameters generate huge technical problems in the implementation of any known and available technology or currently being developed technology to an industrial scale.…”

Overview and Outlook on Utilization Technologies of Low-Concentration Coal Mine Methane

“…CaCO 3 is then heated to regenerate CaO by burning the drainage gas, forming the calcium looping process. 164 Recently, Tremain et al 165 performed the 1 m 3 /s pilot-scale SDL research for VAM abatement. Over 99.5% methane conversion was achieved under 600 °C, and it was found that inventory size and VAM residence time are the key factors influencing the methane conversion.…”