NOVEL CORRELATIONS FOR THE RESIDENCE TIME OF FLUID-SOLID REACTIONS INVOLVING UNIFORMLY SIZED PARTICLES

Abstract

The estimation of the residence time required to achieve a desired conversion in a fluid-solid reaction is computationally demanding. To overcome this problem, there are correlations that allow estimating the residence time with less effort. In this paper, those correlations are reviewed for the case of heterogeneous reactions that can be represented with the shrinking core model, with controlling resistance in mass transfer through the film, in the chemical reaction or in diffusion through the ash. For a single particle size, new correlations are proposed to solve the problem of inaccuracy and lack of analytical solution of traditionally used correlations. The proposed correlations were developed for piston flow reactors and for continuous perfectly mixed reactors. Moreover, it was studied how to use the proposed correlations when the particle size is not uniform. Experimental size distributions available in the literature were used for this purpose. The accuracy of the obtained results is sufficient for a fast reactor design or for the first steps of an optimization algorithm.