Gasification characteristics of rapid thermal pyrolyzer residue in a fluidized bed reactor

A novel process has been developed at KIER (Korea Institute of Energy Research) for upgrading extra-heavy oil fractions. This process uses a rapid thermal pyrolysis (RTP) of extra-heavy oil with a gasifier/combustor of RTP residue to produce syngas as well as to supply heat to the pyrolyzer. Unreacted carbon in RTP residues from the pyrolyzer are used as a feedstock to the gasifier/combustor. The RTP residue is mostly sand with 1 wt % of petroleum coke.The possibility that product gas from the gasifier/combustor can supply heat to the pyrolyzer is examined. A continuous fluidized bed reactor with the maximum capacity of 10 kg/h (0.05 m I.D. × 1.2 m high) was designed and constructed for RTP residue gasification/combustion. Air, oxygen, and steam were used as gasifying agents. The results of gasification are evaluated, including product gas composition, carbon conversion, gas yield, and heating value of the product gases. In air-blown gasification, the HHV (higher heating value) of the product gas ranges from 72.3 to 303.2 kcal/m³, which is lower than that of typical gasification. The carbon conversion is below 0.37, due to the low reactivity of petroleum coke and the diluting effects of nitrogen. In contrast, carbon conversion was greater than 0.93 with a higher equivalence ratio (ER = 1.0) in the O₂-blown gasification mode. Product calorific values of up to 3739 kcal/m³ can be obtained, with the steam serving as a gasifying agent.