Maximizing methane production in adsorptive nitrogen removal from natural gas: The impact of dehydration temperature on Ba-ETS-4 separation performance

Abstract

Ba-ETS-4 is a promising adsorbent for nitrogen removal from low-grade natural gas. However, the Ba-ETS-4 adsorption characteristics, i.e., both adsorption kinetics and equilibrium capacity, change by dehydration temperature owing to structural shrinkage and pore contraction which finally impact the separation performance of the adsorption bed. In this paper, experimental breakthrough data are provided for N₂/CH₄ separation at various Ba-ETS-4 dehydration temperatures (250°C-450 °C) followed by a separation performance analysis in generating methane as the main product. Additionally, isotherm data at different temperatures (20 °C, 40 °C, 60 °C and 80 °C) are presented for selected dehydration temperatures (250 °C, 350 °C, 400 °C and 440 °C). The results revealed that an increase in dehydration temperature leads to a decrease in adsorption capacity but a better separation by providing more hindrance for CH₄ diffusion, while not affecting the N₂ breakthrough wavefront. At a dehydration temperature of 250 °C, the N₂ breakthrough time is the highest, indicating the ability to process a larger feed. However, this also leads to the least CH₄ production (0.037 mmol/g), as most of the fed CH₄ is adsorbed onto the bed. Interestingly, an increase in dehydration temperature leads to an increase in CH₄ production up to 420 °C (0.140 mmol/g), after which the CH₄ production decreases sharply.