Study On Gas Entrained By Regenerated Catalyst For FCC

This study use a small-scale fluidized bed circulation device and two kinds of catalyst with different sizes to explore the law of entrained gas when catalyst is flowing in the inclined pipe. Aerating gas and aerating taps' influence to flowing tone has been researched, and especially, rising gas, catalyst inventory of the fluidized bed, fluidizing gas' influence to catalyst circulating rate and amount of entrained gas has been studied, too. Besides, factors and ways that affect amount of entrained gas of catalyst has been discussed.By measuring the axial pressure of the inclined pipe, it has showed: fluidizability of the catalyst with small size is well, when the particle flowed in the pipe, it permeated the whole pipe and take on a dense-phase flowing tone, however, fluidizability of the catalyst with big size is not as well as the small's, when it flowed in the pipe, it took on a rare-dense phases flowing tone, flowing character of the dense phase in the bottom of the inclined pipe is non-fluidized. After aerating gas entered, the non-fluidized flowing disappeared. The aerating way determined by the experiment is: for the small particles, aerating gas should not enter, but for the big particles, aerating gas should enter from the bottom of the inclined pipe, amount of aerating gas is 37ml/min when amount of rising gas is 5L/min, 75ml/min when amount of rising gas is 25L/min.It has showed by study of catalyst circulate rate: circulate rate increased when amount of rising gas and inventory increased, but it doesn't change with amount of fluidizing gas.In study of the law of entrained gas, value of entrained gas has been determined by meterage of pressure difference of the two ends of the inclined pipe. The experiment results has showed: for the small particles, when amount of the rising gas, inventory and fluidizing gas increased, amount of entrained gas increased, too; for the big particles, amount of the entrained gas increased when amount of the rising gas and inventory increased, but it doesn't change with amount of fluidizing gas.In the course of foundation of the model, firstly the catalyst in the bottom of the fluidized bed has been simplified and analyzed properly to build the physical model, then it has been calculated by law of conservation of mass and momentum to build the mathematic model, lastly the parameters of the model has been regressed and the equation of amount of entrained gas has been put forward according to the experiment results. The forecast values have been compared with the experiment values, and the maximal error is less than 20 %, so the equation is suitable to calculate amount of entrained gas.