Name
Oxygen carrier explosions in chemical looping processes
Description

As fluidized bed chemical looping processes develop at the pilot scale, the challenge of oxygen carrier attrition remains. Small fragments produced by chemical, thermal, and mechanical stresses can accumulate in ducting, windboxes, and filters, and if disrupted by transient operation (startup, shutdown, process changes) can form a dust cloud in a vessel. These materials, under standard test conditions, are generally considered non-explosible for metallurgical applications. However, the elevated temperatures and pressures in chemical looping processes, in addition to the small particle sizes from fragmentation and potential additives to promote reactivity, all create an environment where traditional barriers to dust explosions are reduced or removed. Beyond traditional metal dust explosions, whereby a metal is oxidized in an exothermic process to create an overpressure, chemical looping creates a new explosible condition. This condition is an explosible mixture of metals oxides and reducing gases, which on ignition we term a metal oxide reducing environment (MORE) explosion. This case is unique to chemical looping with exothermically reduced oxygen carriers, particularly by methane (CH4), which exhibit a rise in temperature in addition to an increased gas concentration due to their unique reaction. The severity of this case may be increased by CLOU behaviour, in which case homogeneous combustion kinetics apply. The effect of temperature and pressure, in addition to oxygen carrier and gas composition are discussed from a thermodynamic perspective for explosion severity and safe design requirements. Strategies for particulate management, explosion prevention and mitigation, and downstream equipment management to protect operations are discussed.

Location Name
Max Bell 251
Full Address
Banff Centre for Arts and Creativity
107 Tunnel Mountain Dr
Banff AB T1L 1H5
Canada
Session Type
Poster
Abstract ID
1044