Modelación de la gasificación de biomasa en un reactor de lecho fijo

Abstract

Se realiza la modelación matemática de un reactor de lecho fijo de calentamiento indirecto que tiene en cuenta los procesos de transferencia de calor y de masa y las reacciones químicas que ocurren durante la transformación termoquímica de biomasa a través de los procesos de pirólisis y gasificación. Mediante este modelo se puede predecir la composición de los gases obtenidos y la distribución de temperaturas en el interior del reactor, en cualquier instante de tiempo. El modelo se desarrolla a partir del planteamiento de las ecuaciones de balance de energía y de masa para un sistema heterogéneo compuesto por una fase sólida, correspondiente a la biomasa y el carbonizado y una fase gaseosa, que corresponde al agente de gasificación y la fase volátil generada. No se consideran gradientes ni de concentración ni de temperatura al interior de las partículas que componen la fase sólida. Para la solución del modelo se desarrolla un programa computacional en el lenguaje C++. La discretización de las ecuaciones planteadas se realiza mediante el método de volúmenes finitos. Los resultados obtenidos con el modelo se comparan con resultados experimentales determinados por otros autores en reactores de prueba, obteniéndose resultados aceptables. / Abstract. A mathematical modeling of a fixed bed reactor with indirect heating is performed taking into account the heat and mass transfer processes and the chemical reactions that occur during the thermochemical processing of biomass through pyrolysis and gasification. By means of this model can be predicted the gas composition obtained and the temperature distribution inside the reactor at any time. The model is developed from the approach of the mass and energy balances to a heterogeneous system composed of a solid phase, corresponding to the biomass and char, and a fluid phase, corresponding to the gasification agent and the volatile phase generated. Concentration or temperature gradients within the solid-phase particles are not considered.A computer program in C++ is developed to solve the model. The discretization of the balance equations is performed through the finite volume method. The results obtained with the model fit very well with experimental data determined by other authors in test reactors.

A mathematical modeling of a fixed bed reactor with indirect heating is performed taking in- to account the heat and mass transfer processes and the chemical reactions that occur during the thermochemical processing of biomass through pyrolysis and gasification. By means of this model can be predicted the gas composition obtained and the temperature distribution inside the reactor at any time. The model is developed from the approach of the mass and energy balances to a heteroge- neous system composed of a solid phase, corresponding to the biomass and char, and a fluid phase, corresponding to the gasification agent and the volatile phase generated. Concentra- tion or temperature gradients within the solid-phase particles are not considered. A computer program in C++ is developed to solve the model. The discretization of the balance equations is performed through the finite volume method. The results obtained with the model fit very well with experimental data determined by other authors in test reactors. (Texto tomado de la fuente)