Fluidized bed agglomeration is an important and challenging problem for thermal cracking in fluid cokers. A low coker temperature can be problematic because the bitumen is injected into the fluidized bed with a differ...Fluidized bed agglomeration is an important and challenging problem for thermal cracking in fluid cokers. A low coker temperature can be problematic because the bitumen is injected into the fluidized bed with a different viscosity, resulting in formation of agglomerates of varying sizes, which slows the cracking reactions. In the present study, the bed material agglomeration process during nozzle injection of multi- viscosity liquid was investigated in a fluidized bed operated at different mass ratios of the atomization gas to the liquid jets （GLR= 1%-3.5%） and gas velocities （3.9Umf and 5,9Umf） based on a conductance method using a water-sand system to simulate the hot bitumen-coke system at room temperature. During the tests of liquid-jet dispersion throughout the bed, different agglomeration stages are observed at both gas velocities. The critical amount oftert-butanol in the liquid jets that could lead to severe agglomeration of the bed materials （poor fluidization） at GLR = 1% is about 10 wt% at the low fluidizing gas velocity （3.9Umf） and 18wt% at the high gas velocity （5,9Umf）. This study provides a new approach for on-line monitoring of bed agglomeration during liquid injection to guarantee perfect contact between the atomized liquid and the bed particles.展开更多
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 51276033 and 51541608）.
文摘Fluidized bed agglomeration is an important and challenging problem for thermal cracking in fluid cokers. A low coker temperature can be problematic because the bitumen is injected into the fluidized bed with a different viscosity, resulting in formation of agglomerates of varying sizes, which slows the cracking reactions. In the present study, the bed material agglomeration process during nozzle injection of multi- viscosity liquid was investigated in a fluidized bed operated at different mass ratios of the atomization gas to the liquid jets （GLR= 1%-3.5%） and gas velocities （3.9Umf and 5,9Umf） based on a conductance method using a water-sand system to simulate the hot bitumen-coke system at room temperature. During the tests of liquid-jet dispersion throughout the bed, different agglomeration stages are observed at both gas velocities. The critical amount oftert-butanol in the liquid jets that could lead to severe agglomeration of the bed materials （poor fluidization） at GLR = 1% is about 10 wt% at the low fluidizing gas velocity （3.9Umf） and 18wt% at the high gas velocity （5,9Umf）. This study provides a new approach for on-line monitoring of bed agglomeration during liquid injection to guarantee perfect contact between the atomized liquid and the bed particles.
