Assessment and kinetic study of the upfront nitrogen removal using lithium cycle

Abstract

This research work aims to investigate the feasibility of lithium cycle (Li-Cy) as an upfront removal technology (UNR) to remove nitrogen (N2) from the natural gas (NG). Nitridation experiments conducted at 60, 80 and 100 °C showed the middle temperature to be the optimal condition for operation, yielding lithium conversion and nitrogen uptake rate of up to 80 % and 19 mmol/g, respectively. The optimum reaction and Li-moisture treatment times were found to be 0.5 and 2 hours (F: 0.1 L/min, P: 1 atm). Meanwhile, hydrolysis trials proved using steam as a water source to react with lithium nitride (Li3N) quickly and convert 98 % of solid particles into lithium hydroxide (LiOH) after 2 hours of reaction time. Kinetic model fitting led to an areic reactivities of growth of approximately 0.202 and 125 mol.m−2.min for the nitridation and hydrolysis reactions, respectively. Experimental results proven that high nitrogen uptake rates could be achieved under practical experimental setting. The consumed sorbent’s regeneration is not only possible but also potentially economically attractive. This could be a crucial step in commercialization of UNR technologies in baseload LNG plants in Qatar.