Dynamic characteristics of a shell and plate particle‐SCO 2 moving packed bed heat exchanger with various SCO 2 channel configurations

Abstract

This article proposes a dynamic analysis framework for a shell and plate particle-SCO2 moving packed bed heat exchanger (MPBE) with straight SCO2 channel and four fins-modified SCO2 channels, which contains a static model and a dynamic model. 13 cases covering an initial temperature deviation range of +50 ~ −100 K from design-point case in solids inlet, an initial temperature deviation range of +50 ~ −100 K from design-point case in SCO2 inlet, and a SCO2 inlet velocity range of 1.5 times to 0.05 times are introduced to measure the dynamic characteristics. Dynamic responses of five MPBE configurations to two types of inputs (step-change perturbations and linear-change perturbations) under 13 cases are analyzed. Relaxation times at each case are summarized and compared. A low threshold temperature exists for all five MPBE configurations to avoid oscillations in solids outlet temperature under step-change perturbations in solids inlet temperature, and a low threshold SCO2 inlet temperature just appears in MPBE with straight SCO2 channels under step-change perturbations in SCO2 inlet temperature. Improved MPBE configurations show apparent less relaxation time than MPBE with straight SCO2 channel. Among four fins-modified MPBE configurations, MPBE channels modified with offset rectangular fins on SCO2 side exert the fastest dynamic characteristic in most cases.