Chemical
looping combustion (CLC) has been one of the most attractive
topics for the clean utilization of coal. Based on the staged-gasification
of the solid fuel, a separated-gasification CLC apparatus for coal
was established, which mainly consisted of a gasifier (GR), a reduction
reactor (RR), and an air reactor (AR). This design separated the gasification
of the coal avoiding the direct solid–solid contact between
oxygen carriers and coal which was beneficial to lengthen the life
cycle of the oxygen carriers. The established system was tested under
both cold and hot conditions. The variable conditions of different
amounts of fluidized gas and the air into AR were carried out to verify
the feasibility and the stability of this system. Results indicated
that the system could be operated stably under the variable conditions,
showing acceptable pressure distributions in the reactor system. In
the hot operation, the concentration of CO2 at the outlet
of RR reached a relatively high level (92.7%–93.2%) while the
CO2 concentration at the outlet of AR was 0.93%–1.12%
during the stable durations. However, there was still a problematic
condition, unstable operation of coal screw feeder, which needed further
improvement.