The study on static bifurcation behavior of the immobilized yeast spherical beads for ethanol production

Abstract

运用变分原理和打靶法将分布参数系统的非线性边值问题转化为集总参数系统的初值问题,基于延拓算法,研究了固定床中球形固定化酵母粒子表面乙醇和葡萄糖浓度随参数的变化关系,得出了单颗粒固定化酵母生产乙醇的多定态特性。结果表明:随系统尺度L的变化,方程出现分岔点;方程的解与液相主体浓度有关。在某些条件下酵母粒子表面浓度有三个定态;在多定态区域,随L的增加,方程一个解支的乙醇浓度迅速增加,从而可以在固定床中通过控制粒径而使反应器达到较高的产率。研究结果为固定床反应器的开工及控制提供了重要的理论依据。 Based on the continuation method, the shooting method and variational method were used to investigate steady-state multiplicity characteristic of the distributed parameter system of the immobilized yeast spherical beads in packed-bed reactor. The results show that the bifurcation occurs with the variation of the parameter of the system scale L. The solutions are influenced by the concentration of substrate and ethanol in the liquid phase and three solutions of the concentration on the beads surface exist under some conditions. The concentration of ethanol in one of the branch of solutions increases sharply with L, which is beneficial to the productivity of the reactor by means of controlling the size of the yeast spherical beads in the packed-bed reactor. The results obtained in this paper provides important basis for the control and start-up of the packed-bed reactor.