A loop seal which can separatedly supply particles to the EHE and Riser was designed and its performance was evaluated at room temperature. The operational parameters such as solid aeration gas rate, rate of particle introduction to the loop seal, and slit height to the flow characteristics of particle were investigated. As gas velocity increases in reactor, separation and transportation of particles were stabilized due to adequate fluidization condition and the quantitative supply of the particle was available. However, the separation and supply characteristics of particle is not influenced by slit height. When fluidization condition within loop seal is stable, amount of supplied particles into the EHE or Riser were controlled linearly.