Modelling and numerical analysis on residence time distribution characteristics in continuous high-pressure hydrothermal reactor

Abstract

Residence time distribution (RTD) is significant for reflecting fluid mixing and materials dispersion inside continuous high-pressure hydrothermal reactor. In this work, a model is proposed to precisely fit RTD data in continuous hydrothermal reactor, and the model parameters can be used to analyze the characteristics of RTD. A series of RTD data under different working conditions are obtained by numerical simulation and analyzed by the proposed model to investigate the effects of natural convection, momentum ratio and forced flow on RTD. It is found that appropriate natural convection and momentum ratio are beneficial to fluid mixing and materials dispersion. On the other hand, excessive natural convection and too high or too low branch inflow may lead to the extension of average residence time and materials delay or stagnation. Forced flow is negatively correlated with average residence time but has little influence on materials dispersion and delay.