Abstract

HERNANDEZ-BARAJAS, José R  and  VAZQUEZ-ROMAN, Richart. Severe Operating Conditions in Catalytic Cracking Units and Multiplicity of Steady-States. Inf. tecnol. [online]. 2007, vol.18, n.1, pp.31-40. ISSN 0718-0764.  http://dx.doi.org/10.4067/S0718-07642007000100006.

This paper studies an analyzes the effect of severe operating conditions in catalytic cracking units on multiplicity of steady-states. The model proposed here is based on mass and energy conservative equations and has been able to demonstrate the existence of one to five steady states for both partial and complete combustion regimes. The most common multiplicity is the existence of three steady states that occurs at typical operating conditions. The existence of a unique steady state is produced by an abrupt decrease in both fluidization effectiveness and air distribution inside the regenerator. Attraction domains and dynamic trajectories of each steady state have been determined for this scenario and  is suggested that this phenomenon must be taken into account in the design of a robust control strategy. Finally, it is shown that the existence of five steady states is related to a decreasing of the heterogeneous oxidation rate of carbon monoxide

Keywords : catalytic cracking; multiplicity; dynamics; simulation; combustion.

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