A mass-temperature decoupled discretization strategy for large-scale molecular-level kinetic model

The molecular conversion of complex mixture involves a large number of species and reactions. The corresponding kinetic model consists of a series of ordinary differential equations with severe stiffness, leading to an exponentially growing computational time. To reduce the computational time, we proposed a mass-temperature decoupled discretization strategy for a large-scale molecular-level kinetic model. The method separates the mass balance and heat balance calculations in the rigorous adiabatic reactor model and divided the reactor into several isothermal segments. After discretization, the differential equations for heat balance can be replaced by algebraic equations between nodes. We used a molecular-level diesel hydrotreating kinetic model as the case to validate the proposed method. A good agreement between the discretization model and rigorous model was observed while the computational time was significantly shortened. Moreover, the method was also extended to heavy oil fluid catalytic cracking and accurately calculated the product composition and temperature distribution. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study proposes a mass-temperature decoupled discretization strategy for large-scale molecular-level kinetic models, aiming to reduce computational time. The method divides the reactor into isothermal segments and replaces the heat balance differential equations with algebraic equations, separating the calculations of mass balance and heat balance.