Kinetic Study on Continuous Sampling of Coal Char from a Micro Fluidized Bed

Area of Science:

• Chemical Engineering
• Combustion Science
• Reaction Kinetics

Background:

• Understanding coal char combustion and gasification kinetics is crucial for optimizing energy processes.
• Existing methods often lack the ability to track dynamic changes in char properties during reactions.
• Micro fluidized bed reactors (MFBs) offer controlled environments for studying these phenomena.

Purpose of the Study:

• To design and implement a novel micro fluidized bed reactor (MFB) integrated with an online char particle sampling system.
• To investigate the evolving kinetics of coal char combustion and gasification.
• To analyze the changes in kinetic parameters (pre-exponential factor A and activation energy E) of coal char over time.

Main Methods:

• Self-design of a micro fluidized bed reactor (MFB) coupled with a vacuum online sampling system.
• Continuous sampling of Vientiane coal char from the MFB during reactions.
• Thermogravimetric analysis (TGA) to determine combustion and gasification reactivities of sampled chars.
• Kinetic parameter analysis of the sampled char.

Main Results:

• Char reactivity in oxy-fuel combustion exhibited a decrease-increase-decrease pattern with sampling time.
• Both the pre-exponential factor (A) and activation energy (E) of the sampled char increased over time.
• Gasification reactivity generally increased with sampling time, with a slight initial decrease observed.

Conclusions:

• The developed MFB with online sampling system enables real-time investigation of gas-solid reaction evolution.
• The study provides insights into the dynamic changes in coal char reactivity during combustion and gasification.
• This innovative system is poised to advance future research on reaction kinetics in similar processes.