(743d) Experimental Study of Solid Fuel Agglomeration and De-Agglomeration Behaviors in the Reactions With Metal Oxide Particles

The present work studies the solid fuel agglomeration and de-agglomeration behaviors in the context of chemical looping combustion. A Thermal Gravimetric Analysis (TGA) apparatus is used in this study. PRB coal, Pittsburgh #8 coal, Alabama metallurgic coke, and biomass are used as solid fuels, whereas pure Fe₂O₃ and supported Fe₂O₃ are used as oxygen carrier particles, respectively. In each test, four types of samples are tested: 1) solid fuel powder only; 2) solid fuel powder + 30 wt% oxygen carrier powder; 3) solid fuel powder + 1-2 mm oxygen carrier balls; 4) solid fuel powder + 30 wt% oxygen carrier powder + 1-2 mm oxygen carrier balls. At reducing environment, each sample is heated to 1000 ^oC at 50 ^oC/min, maintained for 10 minutes, and then cooled down to the room temperature. It is found that PRB coal powder and Alabama coke powder form no agglomeration, whereas the biomass powder forms a loose and soft agglomeration only when heated alone. Pittsburgh #8 coal powder forms agglomeration when heated alone or with 1-2 mm oxygen carrier “balls”. However, when mixed with the oxygen carrier “powder”, no agglomeration forms for Pittsburgh #8 coal powder. To prevent the agglomeration of Pittsburgh #8 coal, two anti-agglomeration approaches are tested: 1) low-temperature devolatization (below caking temperature), and 2) high-temperature devolatization (above caking temperature) and subsequent pulverization. Both approaches are found to be able to effectively prevent/mitigate agglomeration of Pittsburgh #8 coal.