Mass fluid catalytic cracking

Fluid catalytic cracking is one of the most important conversion processes in a petroleum refinery. The process incorporates most phases of chemical engineering fundamentals, such as fluidization, heat/mass transfer, and distillation. The heart of the process is the reactor-regenerator, where most of the innovations have occurred since 1942. 

Characterization of Fluid Catalytic Cracking Catalyst Coke by C NMR and Mass Spectrometry... 

Example 9.1. Three students measured the mass of three powders—sand, fluid catalytic cracking catalyst (FCC), and Cas (P04)2—10 times successively in a Scott Volumeter. The data is summarized in Table E9.1. Calculate the Scott density, uncertainty, and repeatability. The volume and uncertainty of the cylinder is 25.00 0.03 cm. ... 

On the industrial scale, some of the ongoing trends in fluid catalytic cracking are shortening of the gas residence time and increasing reaction temperature [2]. These trends together with more active cracking catalysts have led to higher reaction rates, which in turn may cause external mass and heat transfer limitations. 

A series of experiments varying temperature, micro-sphere size and time on stream have been performed in a fixed fluidised bed microactivity reactor to study the role of intraparticle diffusion in commercial fluid catalytic cracking (FCC) catalysts, particularly on gasoline yield and catalyst deactivation by coke deposition, for the cracking of a vacuum gas oil. Additionally, a mechanistic model that describes interface and intrapartide mass transfer interactions with the cracking reactions, has been used to study the combined influence of pore size and intraparticle mass diffusion on the deactivation of FCC catalysts and the gasoline yield. 

D Eulerian-Eulerian simulation of fluid catalytic cracking of gas oil. Snapshot of fluctuations around the statistically stationary species field. Mass fraction in the gas phase (a) gasoil fraction of the feed, (b) gasoline fraction in the product, (c) Transient calculation of the meso-scale fluctuations around a statistically stationary state solids volume fraction and axial velocity at 0.1 m from the wall and 0.25 m from the bottom. 

We further mention that at low values of the Reynolds number (that is at very low fluid velocities or for very small particles) for flow through packed beds the Sherwood number for the mass transfer can become lower than Sh = 2, found for a single particle stagnant relative to the fluid [5]. We refer to the relevant papers. For the practice of catalytic reactors this is not of interest at too low velocities the danger of particle runaway (see Section 4.3) becomes too large and this should be avoided, for very small particles suspension or fluid bed reactors have to be applied instead of packed beds. For small particles in large packed beds the pressure drop become prohibitive. Only for fluid bed reactors, like in catalytic cracking, may Sh approach a value of 2. 

In catalytic cracking the gas oil feed reacts to much lighter compounds, which causes a high convective flux from the catalyst surface to the bulk of the fluid. Therefore Fick s diffusion law is not applicable (assumes equimolar counter-diffusion) in the mass transfer calculations and as a result rigorous Maxwell-Stefan equations must be used. Due to the... 

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