Figure 8 . The mean and standard deviation of the expanded bed height with varying fluidization gas velocity.

3.2. Effect of wood pellets on the fluidization behavior

In this section, fluidization with the addition of 100 wood pellets in the bed relative to case 1 was investigated and compared to the baseline. Note, the static bed height provided in Table 2 corresponds to the LDPE particle bed height for all cases. With the addition of 100 wood pellets, the actual bed is around 2.5 cm higher than the LDPE only case, yet is referred to using the LDPE bed height. Figure 9 shows the snapshots of the binary fluidization of wood and LDPE particles with superficial gas velocity ranging from 1.5 – 3.7 Umf. At 1.5 Umf (Figure 9a), the particle mixture remain segregated, with wood particles sitting at the bottom of the bed due to its larger density. At 2.0Umf (Figure 9b), particle mixture begins to mix, even though at higher elevations only LDPE particles are observed. Different from the LDPE only case that forms spouts with the further increase of superficial gas velocity to 3.0 Umf, at 3.0 Umf and 3.7 Umf, the bed stays in the slugging region with wood particles well mixed with the LDPE particles.