Article pubs.acs.org/IECR
Steady and Transient Characteristics of Catalytic Flow Reverse Reactor Integrated with Central Heat Exchanger Sheng Wang,* Diannan Gao, and Shudong Wang* Dalian National Laboratory for Clean Energy (DNL), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China ABSTRACT: A Pd/Al2O3 monolith catalyst was prepared by wet impregnation. Its excellent performance was demonstrated in the removal of lean methane. After 1000 h of operation, a higher catalytic activity can be sustained. On this basis, a pilot-scale catalytic flow reversal reactor (CFRR) coupled with a central heat exchanger was designed for catalytic removal of ventilation air methane. Experiments showed high methane destruction ratios were achieved at elevated reactor temperatures maintained by reverse flow operations. Transient and steady characteristics of the reactor were also studied experimentally and analyzed under various operating parameters involving methane concentration, cycle period, and heat transfer flux. The coupling of central heat exchanger caused the complex quasi-periodic states and the significant divergences on the reactor behaviors compared with the results in the literature. To further verify the robustness of the heat recovery method, the experimental unit was operated in a long-time course. The lean methane can be efficiently eliminated and utilized.
1. INTRODUCTION Global warming caused by excessive green house gases (GHGs) emission has a negative effect on human life.1 Because of a higher global warming potential (GWP) for methane, its contribution to global warming is next only to carbon dioxide. The methane emission source is more centralized than carbon dioxide. So from this point of view there is an inherent advantage in transforming methane into carbon dioxide. As a relatively concentrated emission source of anthropogenic methane, the utilization and mitigation of coal mine methane is even more important.2 However, a majority of methane is vented from the ventilation shaft, which is called the ventilation air methane (VAM). Because of lower methane concentration (
