The Efficiency of Pd Addition and Sr Substitution on La1−xSrxMnO3 to Remove Ventilation Air Methane in a Catalytic Flow Reversal Reactor

Yanxia Wang,Tao Zhu

doi:10.3390/atmos13010054

Abstract

Ventilation air methane (VAM) is the main cause of greenhouse gas emissions in coal mining. Catalytic flow reverse reactor (CFRR) is widely used in VAM to mitigate methane emissions. In this study, palladium (Pd) and La1−xSrxMnO3 were used as catalysts in a CFRR. Different types of catalysts were prepared by loading La0.8Sr0.2MnO3, La0.9Sr0.1MnO3, and 0.1%Pd-La0.9Sr0.1MnO3 on a cordierite honeycomb reactor coated with γ-Al2O3 to compare their performances. In addition, this study compared the performance of the three catalysts in an 800 °C reactor based on different methane inlet concentrations, inlet speeds, and conversion times. The results showed: (1) 0.1% addition of Pd increased methane conversion. (2) La0.8Sr0.2MnO3 had higher efficiency at lower methane inlet concentrations, whereas La0.9Sr0.1MnO3 was more efficient at higher methane concentrations. This study demonstrates that a higher Sr loading is worth implementing only when the methane concentration of VAM is lower than 0.6%. (3) To achieve a higher methane conversion efficiency, the inlet velocity of methane should also be considered.

Highlights

Substitution on La1−x Srx MnO3 to Remove Ventilation Air Methane in a Catalytic Flow Reversal Reactor
This study demonstrates that a higher Sr loading is worth implementing only when the methane concentration of ventilation air methane (VAM) is lower than 0.6%. (3) To achieve a higher methane conversion efficiency, the inlet velocity of methane should be considered
Air ventilated from coal shafts contains methane in low concentrations (0.1–1 vol.%) called ventilation air methane (VAM)

Summary

Introduction

Substitution on La1−x Srx MnO3 to Remove Ventilation Air Methane in a Catalytic Flow Reversal Reactor. Compared to traditional flame combustion, catalytic flameless combustion has a clear advantage. It features a lower temperature, higher conversion, no energy loss by flame [4], and negligible formation of noxious by-products such as NOx [5]. One of the most promising utilization technologies of VAM is the use of a reverse flow reactor (RFR). RFR consists of a catalytic fixed-bed reactor in which the feed flow direction is periodically reversed [6]. The use of the catalyst in CFRR significantly decreases the reactor temperature and allows better control of reaction over a wider fuel/air ratio without affecting the flammability [9,10]

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Results