On transfer function formalism for chemical reactor monitoring by continuous flow techniques

Mathematical expressions for the response of a flow-through system for reactor monitoring have been obtained considering the transfer function formalism, where the output of a linear system to an arbitrary input signal could be known by means of the transfer function of this linear system. A transfer function without and with a pseudo-first order chemical reaction based on an axial dispersion model is proposed. These transfer functions allow the description of a great variety of situations as the dynamic response of the system equations against impulse, step and pulse perturbations. Two empirical parameters related with the diffusion coefficient of the solute and geometrical magnitudes of the flowing system are proposed. The model has been checked experimentally studying the dispersion of different non-reacting dye solutions and the kinetics of phenolphthalein decolouration in alkaline media.