Record Types
Records with Type: Thesis
Hydrodynamics in Recirculating Fluidized Bed Mimicking the Stripper Section of the Fluid Coker
Francisco Sanchez Careaga
October 30, 2018 (v1)
Keywords: Agglomerates Drying Model, Baffles, Fluid Cokers, Fouling, Radioactive Particle Tracking, Recirculating Fluidized Beds, Sheds
The stripper section of a Fluid CokerTM consists of a system of baffles (sheds) that enhances the removal of interstitial and adsorbed hydrocarbon vapors from the fluidized coke-particles. Most of the hydrocarbon-vapors released below a stripper shed flow up to the stripper shed, where they may crack and form coke deposits that foul the shed. Extensive fouling changes the shapes of the sheds, makes them thicker and reduces the free-space between the adjacent sheds until downward solids flow is so impaired that the Coker has to be shut down. The Radioactive Particle Tracking (RPT) technique allows the determination of a radioactive tracer-particle location within a certain space inside a fluidized bed and has been the main tool used to study the motion of agglomerates and their interactions with internals. The research presents an innovative use of the RPT system, as a tool to measure the growth of internals fouling in time without the need of stopping the process. Moreover, the techniq... [more]
Un Nuevo Método de Identificación de Procesos Continuos no Oscilatorios de Alto Orden
Francisco Sanchez Careaga
October 30, 2018 (v1)
Keywords: Dynamic System Analysis, Process Control, Process Intensification, Process Modelling
Continuous processes with time delay, in general, have been represented by using first order models with time delay (FOMTD). For this models, the parameter can be graphically estimated by plotting the process response when a step is applied to the manipulated variable. For higher order process, the FOMTD have poor results and the second order models with time delay (SOMTD) are more suitable for identifying the process. Nevertheless there is no simple graphic method for estimating the parameters of the SOMTD.

This research presents a simple graphic method for estimating the second order model with time delay parameter. The method requires to read four point of the process response when a step change in the manipulated variable is applied. From these readings the values of the time delay, gain and time constants of the SOMTD model are estimated.

Moreover, in this research, and alternative approximation of the time delay is proposed, this to avoid unstable zeros on the controller e... [more]
Los procesos continuos con tiempo muerto, generalmente han sido representados utilizando modelos de primer orden con tiempo muerto (FOPDT). Para este modelo, los parámetros pueden ser estimados gráficamente utilizando la gráfica de la respuesta del proceso, al aplicársele un escalón en la manipulación del mismo. Para procesos de alto orden, los modelos FOPDT dan pobres resultados y los modelos de segundo orden con tiempo muerto (SOPDT) son los más indicados para responder a las necesidades de identificación. Sin embargo no existe un método gráfico sencillo para estimar los parámetros del modelo SOPDT.

En esta investigación se presenta un método gráfico sencillo para estimar los parámetros del modelo de segundo orden con tiempo muerto. El método consiste en la lectura de cuatro puntos de la gráfica de respuesta del proceso real al aplicársele un cambio tipo escalón en la manipulación. De esas lecturas se estiman los valores del tiempo muerto, de la ganancia, y de las constantes de t... [more]
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